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...

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 ...

We propose a comprehensive nonlinear ODE-based thermo-hydraulic model of district heating system featuring several heat producers, consumers and storage devices which are interconnected through distribution network meshed topology whose temperature dynamics explicitly considered. Moreover, we analyze the conditions under hydraulic thermal subsystems exhibit shifted passivity properties. For sub...

Classical Geostatistics methods have been designed to use mainly statistical knowledge about natural variables and they lack the ability to incorporate important forms of knowledge like physical laws and scientific theories into the mapping process. On the other hand, the powerful and versatile Bayesian maximum entropy (BME) method of Modern Geostatistics can accomplish such a task, rigorously ...

Upscaled soil hydraulic properties are needed for many large-scale hydrologic applications such as regional and global climate studies and investigations of land–atmosphere interactions. Many larger scale subsurface flow and contaminant transport studies also require upscaled hydraulic property estimates. The objectives of this study were to develop a methodology for upscaling hydraulic propert...