Search results for "Environmental engineering"
showing 10 items of 2674 documents
Effect of Hydrogen and Absence of Passive Layer on Corrosive Properties of Aluminum Alloys
2020
This paper reports the results of research on the effect of hydrogen permeation and the absence of passive layers on the variations in the corrosive properties of aluminum alloys. The study demonstrated that such variations contribute to the deterioration of corrosive properties, which in turn contributes to shortening the reliability time associated with the operation of aluminum alloy structures. The analysis involved structural aluminum alloys: EN AW-1050A, EN AW-5754, and EN AW-6060. It was demonstrated that the absorption of hydrogen by the analyzed alloys led to the shift of the electrode potential to the negative side. The built hydrogen corrosion cells demonstrate in each case the f…
Advancements in Sustainable PVDF Copolymer Membrane Preparation Using Rhodiasolv® PolarClean As an Alternative Eco-Friendly Solvent
2021
In this work, Rhodiasolv® PolarClean was employed as a more sustainable solvent for the preparation of poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) flat sheet membranes via phase inversion technique by coupling vapour induced phase separation (VIPS) and non-solvent induced phase separation (NIPS) processes. Preliminary calculations based on Hansen solubility parameters well predicted the solubilization of the polymer in the selected solvent. The effect of exposure time on humidity and the influence of polyethylene glycol (PEG), polyvinyl pyrrolidone (PVP) and sulfonated polyether sulfone (S-PES) on membrane properties and performance, were evaluated. Three different coagulation …
The efficient mixed matrix antifouling membrane for surfactant stabilized oil-in-water nanoemulsion separation
2019
Abstract Membrane technology has raised considerable interest in sustainable water purification over the past decade. The development of antifouling membranes is always the basic approach to address the omnipresent bottlenecks of the membrane fouling. In this study, AlSi2O6 nanoparticles were synthesized using a coprecipitation technique and their influence was investigated on the permeation and antifouling properties of ultrafiltration (UF) membranes of polysulfone (PSF). A series of membranes were fabricated with various concentrations (such as 0.0, 2.5, 5 and 7.5 wt%) of AlSi2O6 nanoparticles through diffusion induced phase separation method. The prepared composite membranes demonstrate …
VALORISATION OF FOREST AND AGRICULTURAL BIOMASS FOR THE SPANISH CERAMIC TILE INDUSTRY
2015
Since ceramic tile industry is an energy intensive industry, European ceramic companies are challenged to reduce their CO2 emissions in the medium and long-term. According the Roadmap for moving to a low-carbon economy in 2050 (European Commission, 2011) the objective is to achieve a reduction in CO2 emissions of between 34 % and 40 % by 2030, and between 83 % and 87 % by 2050. In the present paper we present a study on the viability of the incorporation of biofuels in the energy mix of the Spanish ceramic industry with the objective of (1) identifying the potential use of biomass resources, with a special focus of forest and agricultural biomass, in the manufacturing process of ceramic til…
Service Life of Cementitious Photocatalytic Paints Newly Formulated
2013
The use of photocatalytic products for surface coating of buildings contributes to the sustainability of building interventions, due to the reduction of some atmospheric pollutants and self-cleaning attitude. The world market produces a wide range of coatings, applied in limited thickness, transparent and opaque, high initial performance, although data on their durability are still missing. The knowledge of the performance over time of such innovative products is necessary according to the new EU Regulation No. 305/2011, which introduced for construction works, the seventh requirement on their sustainability and particularly their durability. The study concerns the evaluation of the durabil…
Greenhouse gas emissions from integrated urban drainage systems: where do we stand?
2018
As sources of greenhouse gas (GHG) emissions, integrated urban drainage systems (IUDSs) (i.e., sewer systems, wastewater treatment plants and receiving water bodies) contribute to climate change. This paper, produced by the International Working Group on Data and Models, which works under the IWA/IAHR Joint Committee on Urban Drainage, reviews the state-of-the-art and modelling tools developed recently to understand and manage GHG emissions from IUDS. Further, open problems and research gaps are discussed and a framework for handling GHG emissions from IUDSs is presented. The literature review reveals that there is a need to strengthen already available mathematical models for IUDS to take …
Explicit equations for uniform flow depth
2017
Conventional approach in uniform open channel flow is to express the resistance coefficient in the Manning, Darcy-Weisbach or Chezy form. However, for practical cross-sections, including rectangular and trapezoidal ones, the governing equation is implicit in the uniform water depth. For these sections the water depth, corresponding to known values of the flow discharge, slope channel and resistance coefficient, is presently obtained by trial and error procedure. In this paper exact analytical solutions of uniform flow depth for rectangular and trapezoidal section have been obtained in the form of fast converging power series.
A simulation/optimization model for selecting infrastructure alternatives in complex water resource systems
2010
The paper introduces a simulation/optimization procedure for the assessment and the selection of infrastructure alternatives in a complex water resources system, i.e. in a multisource (reservoirs) multipurpose bulk water supply scheme. An infrastucture alternative is here a vector X of n decision variables describing the candidate expansions/new plants/water transfers etc. Each parameter may take on a discrete number of values, with its own investment cost attached. The procedure uses genetic algorithms for the search of the optimal vector X through operators mimicking the mechanisms of natural selection. For each X, the value of the objective function (O.F.) is assessed via a simulation mo…
Multi-scenario multi-objective robust optimization under deep uncertainty: A posteriori approach
2021
This paper proposes a novel optimization approach for multi-scenario multi-objective robust decision making, as well as an alternative way for scenario discovery and identifying vulnerable scenarios even before any solution generation. To demonstrate and test the novel approach, we use the classic shallow lake problem. We compare the results obtained with the novel approach to those obtained with previously used approaches. We show that the novel approach guarantees the feasibility and robust efficiency of the produced solutions under all selected scenarios, while decreasing computation cost, addresses the scenario-dependency issues, and enables the decision-makers to explore the trade-off …
An improved sampling strategy based on trajectory design for application of the Morris method to systems with many input factors
2012
[EN] In this paper, a revised version of the Morris approach, which includes an improved sampling strategy based on trajectory design, has been adapted to the screening of the most influential parameters of a fuzzy controller applied to WWTPs. Due to the high number of parameters, a systematic approach has been proposed to apply this improved sampling strategy with low computational demand. In order to find out the proper repetition number of elementary effects of each input factor on model output (EEi) calculations, an iterative and automatic procedure has been applied. The results show that the sampling strategy has a significant effect on the parameter significance ranking and that rando…