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...

1 Hans Kleine Büning, Benno Stein ABSTRACT Configuration is a process of creating complex systems out of a finite set of predefined objects. This process may enclose the selection, the assemblage and the adaptation of these objects. In this paper we want to describe how the configuration of hydraulic plants can be supported. A hydraulic plant is a complex system that consists of electronic, mec...

In this study, a nonlinear sliding-mode controller is designed for force tracking of a piezoelectric-hydraulic pump (PHP)-based actuation system, which is developed to replace the current electro-hydraulic actuation systems for automatic transmission (AT) friction elements, such as band brakes or clutches. By utilizing the PHP, one can eliminate the various hydraulic components (oil pump, regul...

This paper presents the design and experimental evaluation of an explicit force controller for a hydraulic actuator in the presence of signi"cant system uncertainties and nonlinearities. The nonlinear version of quantitative feedback theory (QFT) is employed to design a robust time-invariant controller. Two approaches are developed to identify linear time-invariant equivalent model that can pre...

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...

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 ...

In order to improve the management and to better locate water losses, Water Distribution Networks can be physically divided into District Meter Areas (DMAs), inserting hydraulic devices on proper pipes and thus simplifying the control of water budget and pressure regime. Traditionally, the water network division is based on empirical suggestions and on ‘trial and error’ approaches, checking res...

Laboratory soil column experiments were conducted to study the distribution of preferential flow paths resulting from removal of fine-size clay particles. These experiments specifically studied the influence of clay (kaolinite) percentage in sand-clay mixtures and the effect of hydraulic gradients on pore evolution. Analysis of the effluent during the experiments indicated that clay particles w...