Search results for "Water science"

DORA algorithm for network flow models with improved stability and convergence properties

2001

A new methodology for the solution of shallow water equations is applied for the computation of the unsteady-state flow in an urban drainage network. The inertial terms are neglected in the momentum equations and the solution is decoupled into one kinematic and one diffusive component. After a short presentation of the DORA (Double ORder Approximation) methodology in the case of a single open channel, the new methodology is applied to the case of a sewer network. The transition from partial to full section and vice versa is treated without the help of the Preissmann approximation. The algorithm also allows the computation of the diffusive component in the case of vertical topographic discon…

Emulation of 2D Hydrodynamic Flood Simulations at Catchment Scale Using ANN and SVR

2021

Two-dimensional (2D) hydrodynamic models are one of the most widely used tools for flood modeling practices and risk estimation. The 2D models provide accurate results

The numerical simulation of microstructure

2002

Advanced Techniques for Design and Manufacturing in Marine Engineering

2022

Modern engineering design processes are driven by the extensive use of numerical simulations, and naval architecture as well as ocean engineering are no exception. Structural design or fluid dynamic performance evaluation can only be carried out by means of several dedicated pieces of software. Classical naval design methodology can take advantage of the integration of these pieces of software, giving rise to more robust design in terms of shape, structural and hydrodynamic performances, and manufacturing processes. This Special Issue (SI) on “Advanced Techniques for Design and Manufacturing in Marine Engineering”, published in the Journal of Marine Science and Engineering, aimed to invite …

Effects of temperature on post-methanation of digested dairy cow manure in a farm-scale biogas production system.

2003

A post-methanation process that could be adopted at farm-scale, operating at temperatures prevailing in farm manure digester post-storage tanks, was evaluated. Digested manure samples from a farm digester (35 degrees C) and post-storage tank (5-10 degrees C) were incubated in parallel batches at 5-20 degrees C and as reference at 35 and 55 degrees C. Specific methane yields (kg(-1) volatile solids (VS)(added waste)) were 0.20-0.26 m3 at 35-55 degrees C and 0.085-0.09 m3 at 10-20 degrees C for digester material (345 days of incubation) and 0.16-0.21 m3 at 35-55 degrees C, 0.053-0.087 kg(-1) VS(added waste) m3 at 15-20 degrees C and 0.026 m3 at 10 degrees C for post-storage tank material (250…

Economic effects of the consolidation of water utilities in Japan

2014

Water utilities are affected by economies of scale. However, in Japan most water utilities are small-scale water services. Therefore, they face enormous difficulties in terms of financial and personnel resources. To take advantage of economies of scale, the consolidation of water utilities has been promoted since 1965 by Japanese water authorities. The measure has been successful to some extent; nevertheless, consolidation has not progressed in recent years as was expected. This paper identifies the main barriers that hinder the consolidation of water utilities in Japan and describes the new promotion plan for the consolidation of water utilities developed by the Japan Water Works Associati…

Structure and Sensory Analyses of Tainting Substances in Finnish Freshwater Environments

1988

GC/MS/SNIFF/TASTE methods have been used in Finland to identify the causes of three tainting problems in water and one in fish nets. Structure determination was often verified by comparison with authentic compounds. Algal growth was implicated to be the source of geosmin and MIB in river water in Northern Finland and was associated with the appearance of tainting problems in raw water and reservoir water in Åland county. Terpenoids (e.g. camphor), degradation products of natural lipids (e.g. aldehydes, ketones and unsaturated aliphatic compounds) and volatile organohalogen compounds were frequently found in contaminated water but showed minor tainting effects compared to geosmin and MIB. Di…

Valuing water supply infrastructure improvements using life satisfaction data as a complement to contingent valuation

2019

Estimating willingness to pay for desalinated seawater: the case of Djerba Island, Tunisia

2017

AbstractWater scarcity can be a growth-limiting factor. Non-conventional water resources, such as desalinated water, represent an alternative means of guaranteeing access to water while reducing water stress. In this study, a contingent valuation survey carried out in Djerba Island, Tunisia, allows the joint modelling of two decisions: societal support for the construction of a desalination plant and households’ willingness to pay for desalinated water. To the best of the authors’ knowledge, no study to date has addressed this relationship. We find that although a clear majority of households are in favour of using desalinated water, far fewer are willing to pay for it. The article conclude…

State and parameter update in a coupled energy/hydrologic balance model using ensemble Kalman filtering

2012

Summary The capability to accurately monitor and describe daily evapotranspiration (ET) in a cost effective manner is generally attributed to hydrological models. However, continuous solution of energy and water balance provides precise estimations only when a detailed knowledge of sub-surface characteristics is available. On the other hand, residual surface energy balance models, based on remote observation of land surface temperature, are characterised by sufficient accuracy, but their applicability is limited by the lack of high frequency and high resolution thermal data. A compromise between these two methodologies is represented by the use of data assimilation scheme to include sparse …