1,814 research outputs found
Pressure-less joining materials for SiC-based components for light water reactors
Get PDFSilicon carbide fiber-reinforced composites (SiC/SiC) are leading candidates to replace zirconium-based alloys as cladding in light water reactors (LWR), owing to their exceptional oxidation resistance and mechanical performance under accident conditions. However, pressure-less joining methods compatible with the extreme chemical and thermal environment of LWRs remain a major technological hurdle. This work evaluates two promising joining materials—Mo-wrap (a MoSi₂/Si composite) and SAY (a silica–alumina–yttria glass-ceramic)—under simulated LWR conditions. Joining was performed using both conventional furnaces and laser-assisted techniques. Joint integrity and microstructure were assessed by SEM/EDS and X-ray computed tomography. Hydrothermal stability was evaluated in static and flowing-water (loop) autoclaves up to 30 days at 330 °C and 150–155 bar. Mo-wrap joints showed partial degradation due to silicon dissolution, while SAY joints retained good structural integrity in static tests but suffered phase-selective corrosion under flowing conditions, with keivite emerging as the most stable crystalline phase. Laser-processed amorphous SAY joints exhibited improved corrosion resistance, though still limited under prolonged exposure. These findings advance the understanding of joining performance in nuclear-relevant environments and support the development of accident-tolerant fuel cladding.</p
Incluso: Social software for the social inclusion of marginalized youth
Get PDFINCLUSO: Social software for the social inclusion of marginalized youth
Can ICT, and more specifically social software, support welfare organizations in their work with marginalized young people? This was the main research question addressed in INCLUSO, a research project funded by the European Commission’s 7th Framework Programme. In this paper, the authors start by introducing the concepts of social exclusion, e-inclusion and the digital divide. They discuss the concept of social software, its use by youngsters and the potential of social software to contribute to social inclusion. The authors then report on the organizational challenges met as they guided four social welfare organizations from Austria, Belgium, Poland and the UK in their implementation of social software tools to support their interaction with marginalized young people. They identify these challenges and present tools to assist social work organizations in defining successful strategies for adopting ICT and social software within their organizations.
INCLUSO: Sociale software ten behoeve van sociale inclusie van gemarginaliseerde jongeren
In hoeverre kan ICT, en in het bijzonder het gebruik van sociale software, een bijdrage leveren aan de sociale inclusie van kansarme jongeren? Wat is de rol van welzijnsorganisaties in dit proces en wat zijn de voornaamste belemmeringen voor het gebruik van sociale software als middel om sociale inclusie te stimuleren? Deze vragen stonden centraal in het INCLUSOproject, een onderzoeksproject dat werd gefinancierd door de European Commission’s 7th Framework Programme. Dit artikel start met een toelichting op concepten als sociale uitsluiting, digitale inclusie en digital divide. Ook wordt ingegaan op het gebruik van social software door jongeren en de potentie ervan voor sociale inclusie. De auteurs doen vervolgens verslag van de organisatorische uitdagingen die ontstonden bij de begeleiding van vier welzijnsorganisaties, bij de implementatie van social software ten behoeve van sociale inclusie. Zij identificeren deze uitdagingen en presenteren hulpmiddelen die welzijnsorganisaties behulpzaam kunnen zijn bij het zoeken naar succesvolle strategieën om ICT en sociale software in hun organisatie toe te passen
Electrified Haber-Bosch Process: Green Ammonia Production
No full textThis report provides a design for a new process to make the ammonia-producing Haber-Bosch process more sustainable by reducing its CO2 emissions. It presents different elements of a process design with most importantly; process diagrams, mass and energy balances and a techno-economic analysis. The most important differences in this process is the use of water electrolysis and nitrogen production. This process emits approximately 50% less CO2 than regular Haber-Bosch methods. Nevertheless, the techno-economic analysis shows that this method is very expensive and that ammonia can only be sold at an acceptable price conform to the market with subsidies on electricity prices and can only become competitive if CO2 taxes are implemented for classic Haber-Bosch plants.Renewables Based Energy Conversion and StorageWB3595 Design ProjectMechanical Engineering | Process and Energy Technolog
Harmonic analysis of corroding systems considering diffusion phenomena
No full textDue to the nonlinear nature of a corroding system, a sinusoidal potential distortion results in an ac current response, which contains higher harmonics. These harmonics can be measured and evaluated to obtain kinetic information, for example the corrosion rate and Tafel parameters. A model was developed for the case that the anodic reaction was charge transfer controlled and the cathodic reaction was under mixed control, i.e., both the charge-transfer and diffusion determine the reaction rate. This model was used to obtain the corrosion rate and Tafel parameters for the corrosion of mild steel in an aerated sodium sulfate solution.status: Publishe
A theoretical study of AC-induced corrosion considering diffusion phenomena
No full textThe effect of AC-induced voltages on corrosion systems was investigated. Two cases were distinguished: the anodic and cathodic reactions were under activation control, the anodic reaction was under activation control and the cathodic reaction was under mixed control. For the first case simple relations could be derived that relate the AC-induced voltage with the corrosion potential and corrosion rate. For the second case numerical analysis was necessary to obtain these relations. It was shown that the influence of the AC-induced voltages on the corrosion behaviour strongly depended on the Tafel parameters. As the cathodic reaction was under mixed control the increase of the corrosion rate was limited to the diffusion-limited current density. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.status: Publishe
Differentiation of SCC Susceptibility with EIS of Alloy 182 in High Temperature Water
No full textElectrochemical Impedance Spectroscopy (EIS) measurements were carried out in high temperature water with Ni-based Alloy-182. The aim was to correlate the EIS results with differences in Stress Corrosion Cracking (SCC) susceptibility that is present around the Ni-NiO transition. There was a clear difference between the EIS results at and away from the Ni-NiO transition. To make a more quantitative correlation a simple equivalent circuit was used to fit the experimental data. A clear correlation between the CPE exponent (n) and the SCC susceptibility could be obtained. Additionally, it was shown that the high frequency arc of the EIS data was related to the diffuse double laye
Supplemental material for Clinical prediction of thrombectomy eligibility: A systematic review and 4-item decision tree
No full textSupplemental material for Clinical prediction of thrombectomy eligibility: A systematic review and 4-item decision tree by Gaia T Koster, T Truc My Nguyen, Erik W van Zwet, Bjarty L Garcia, Hannah R Rowling, J Bosch, Wouter J Schonewille, Birgitta K Velthuis, Ido R van der Wijngaard, Heleen M den Hertog, Yvo BWEM Roos, Marianne AA van Walderveen, Marieke JH Wermer and Nyika D Kruyt in International Journal of Stroke</p
Green Haber-Bosch Process:A Small-Scale Ammonia Reactor System Design
No full textThe global energy transition from a fossil fuel base energy system to a renewable energy source base system is the key mission for a low-carbon future. The target of CO2 emission reduction by 2050, following the Paris Climate Agreement, is 90% compared to the CO2 level of 1990. Haber-Bosch process is the main industrial procedure for the production of ammonia today and about 80% of the global ammonia is consumed by the fertilizer industry. However, the century old Haber-Bosch process is normally energized by fossil fuel and itreleases about 3% of the global carbon footprint. In light of this fact, replacing the conventional fossil fueled Haber-Bosch process for manufacturing ammonia with renewable source powered ammonia production is the main goal of this study. Instead of obtaining H2 from steam-reformed CH4, H2 is produced from electrolyzed H2O. This transition enables the conventional ammonia manufacturing process transforming into a green Haber-Bosch production of ammonia. Two Dutch companies, TNO and Zero Emission Fuels, are cooperatingand developing a small scale of reactor system that can convert ammonia from air and water by using solar PV panels. In this work, a new design of ammonia reactor system is developed. Ammonia is typically formed at high pressure (150 - 250 bar) and high temperature (400 - 500oC) using a promoted iron base catalyst. High temperature ensures rapid reaction kinetics, and high pressure boosts the product yield. Here a reactor system, that is operated at lower pressure (≤100 bar) and uses condensation to remove ammonia, is kinetically simulated in ASPEN. The effect of different operation conditions - reaction temperature (300oC, 350oC and 400oC) , pressure (50, 75 and 100 bar) and feed gas (N2 : H2) ratio (1 : 3 and 1 : 5) - on the production rate in a small-scale ammonia reactor have been systematically computed. The mass flow rate of the single pass reactor is set to 50 g/h in this work. With a catalyst bed length of 15 cm and inner diameter of 3.6 cm, according to the simulation, reaction temperature of 400oC and operating pressure of 100 bar can lead to the highest conversion (40%) in a single pass reactor. The average heat transfer area of the reactor system is to a great extend less than 50 m2, therefore, the double pipe heat exchanger is a favorable heat exchange system for the proposed reactor system. In the reactor design validation section, the selected optimum operation conditions are tested in the same scale reactor laboratory setup. Experimental results show that the single pass conversion of nitrogen at 400oC and 100 bar in such a small-scale reactor can reach 15.4% which is in the range of the industrial one pass conversion level. For reaction operated at 50 bar, 6% of ammonia yield is obtained. It is clear that ammonia production in small-scale and in milder operation condition is possible and the results are promising. The techno-economic analysis has been performed based on above mentioned outcome. The reactor system is integrated with ZEF AEC, ZEF compressor system and a membrane nitrogen separation system. With current ammonia design production (350 g/day), the cost of ammonia per kilogram can be achieved in the range of €1.8 to €2 depending on the operation condition. This is about 5 times more than fossil ammonia prices, but it is very competitive with biomass ammonia. In accordance with the sensitivity analysis, increasing the capacity of feed gas production or reducing the cost in plant equipment can remarkably reduce the ammonia price to less than 1 €/kg NH3. Furthermore, recommendations in four categories are discussed in the last section of this work, which can lead to a further step towards a green ammonia plant in small-scale.Mechanical Engineering | Process and Energy Technolog
Ontologies, Different Reasoning Strategies, Different Logics, Different Kinds of Knowledge Representation: Working Together
Get PDFThe recent experiences in the building, maintenance and reuse of ontologies has shown that the most efficient approach is the collaborative one. However, communication between collaborators such as IT professionals, librarians, web designers and subject matter experts is difficult and time consuming. This is because there are different reasoning strategies, different logics and different kinds of knowledge representation in the applications of Semantic Web. This article intends to be a reference scheme. It uses concise and simple explanations that can be used in common by specialists of different backgrounds working together in an application of Semantic Web
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