labyrinth spillway is an appropriate option to pass pmf discharge. the most advantages of this type of spillway are higher discharge capacity, easy aeration as well as low fluctuations of flow surface. it is essential to find the optimum geometry considering the maximum passing discharge under specific hydraulic conditions with minimum construction cost. in this study, fuzzy inference system (f...

In this paper the control problem of a hydraulic servo-system is addressed. The performance achievable by classical linear controllers, e.g. PD, are usually limited due to highly nonlinear behavior of the hydraulic dynamics. This paper adopts the backstepping design strategy to develop a Lyapunov-based nonlinear controller for a hydraulic servo-system. Load, hydraulic and valve dynamics are inc...

Editorial Board Eric Britton, Managing Director, EcoPlan International, The Centre for Technology & Systems Stud ies, 10 rue Joseph Bara, 75006 Paris, France. Paul Tra nter , Senior Lecturer, School of Geography & Oceanography, Un iversity College, Australian Defence Force Academy, Canberra ACT 2600, Australia. John Ho we, Professor of Transportation En gineering & Head of Infrastructural En gi...

A lysimeter station has been set up by AMRA for the study of the reactive transport of contaminants in soil at the field-scale. It consists of eight lysimeters that can operate individually and simultaneously. Each lysimeter is a steel cylinder (diameter 1.14m, height 2m) filled with an undisturbed soil monolith, whose upper surface is directly exposed to the external environmental agents. A se...

Recent increases in the use of hydraulic fracturing (HF) to aid extraction of oil and gas from black shales have raised concerns regarding potential environmental effects associated with predictions of upward migration of HF fluid and brine. Some recent studies have suggested that such upward migration can be large and that timescales for migration can be as short as a few years. In this articl...

Generic, ready-to-use preliminary design methodologies for aircraft utility systems, made available by means of a Computer Aided Engineering (CAE) tool do not exist. An attempt is made to apply principles used in preliminary aircraft design to preliminary design of utility systems. This is demonstrated for the flight control and hydraulic system. The Computer-Aided Engineering tool consists of ...

This paper reviews four critical mechanisms for successful applications of hydraulic fracturing that have emerged or grown in importance over the past 2 decades. These critical issues are managing height growth, decreasing near-wellbore tortuosity, predicting and engineering network versus localized growth geometry, and promoting simultaneous growth of multiple hydraulic fractures. Building on ...

Abstract In general two basic methods are used for controlling the velocity of a hydraulic cylinder. First by an axial variable-displacement pump for controls flow to the cylinder. This configuration is commonly known as a hydrostatic transmission. Second by proportional valve powered by a constant-pressure source, such as a pressure compensated pump, drives the hydraulic cylinder. In this stud...

This paper presents the design of a highly efficient pneumatic motor system. The air engine is currently the most generally used device to convert potential energy of compressed air into mechanical energy. However, the efficiency of the air engines is too low to provide sufficient operating range for the vehicle. In this study, the energy contained in compressed air/pressurized hydraulic oil is...