254 research outputs found
[catalog] Catalogue des tableaux, aquarelles, dessins, objets d'art, porcelaines, faïences, bronzes, cuivres, objets divers dépendant de la succession de Henriette Van Humbeck : vente 19 Novembre 1908.
No full textGeannoteerd met prijzen; Naam van de eigenares van de collectie (oorspronkelijk : "Clémence Van Humbeeck") gecorrigeerd op de omslag en titelp. in "Henriette Van Humbeeck"Bijzondere collectie
Exercices de mathématique générale I: (relatifs au cours du Professeur J. Janssen)
No full textSYL-010761 = Fascicule 1 ;SYL-010760 = Fascicule 2 ;SYL-011641 = Fascicule 7 ;SYL-005191 = Techniques de dérivation et d'intégrationFascicule 2 :Structures algébriques et nombres. Eléments de logique et applications -- Fascicule 7 :IntégralesFascicules 1, 2 et 7 :Exercices rédigés par M. Anciaux, F. Quertainmont, J.M. Reinhard et F. Van Humbeeck ;Techniques de dérivation et d'intégration :exercices rédigés par M. Anciaux, F. Quertainmont, J.-M. Reinhard1e candidature en sciences économiques ;1e candidature école de commercePremière édition 1976-1977info:eu-repo/semantics/published
Mechanical and electrical properties of selective laser melted parts produced from surface oxidized copper powder
No full textSelective laser melting of pure copper is challenging because of its high optical reflectivity and thermal conductivity. Accordingly, the surface of pure copper powder was modified by oxidation to enhance the optical absorption. The powder with improved optical absorption facilitated the production of crack‐free and dense copper parts at relatively lower laser energy density in both argon and nitrogen atmosphere. The microstructural analysis demonstrated the presence of stable melt tracks without obvious porosity. A very high electrical conductivity of ~89% of the international annealed copper standard, the hardness of ~93 HV, a tensile strength of ~270 MPa, and ductility of ~28% were achieved in the as‐built condition.sponsorship: Agentschap Innoveren en Ondernemen (VLAIO)|150010status: Accepte
Humbeeck, Critical overview of Nitinol surfaces and their modifications for medical applications
No full textAbstract Nitinol, a group of nearly equiatomic shape memory and superelastic NiTi alloys, is being extensively explored for medical applications. Release of Ni in the human body, a potential problem with Nitinol implant devices, has stimulated a great deal of research on its surface modifications and coatings. In order to use any of the developed surfaces in implant designs, it is important to understand whether they really have advantages over bare Nitinol. This paper overviews the current situation, discusses the advantages and disadvantages of new surfaces as well as the limitations of the studies performed. It presents a comprehensive analysis of surface topography, chemistry, corrosion behavior, nickel release and biological responses to Nitinol surfaces modified mechanically or using such methods as etching in acids and alkaline solutions, electropolishing, heat and ion beam treatments, boiling in water and autoclaving, conventional and ion plasma implantations, laser melting and bioactive coating deposition. The analysis demonstrates that the presently developed surfaces vary in thickness from a few nanometers to micrometers, and that they can effectively prevent Ni release if the surface integrity is maintained under strain and if no Ni-enriched sub-layers are present. Whether it is appropriate to use various low temperature pretreatment protocols (6160°C) developed originally for pure titanium for Nitinol surface modifications and coatings is also discussed. The importance of selection of original Nitinol surfaces with regard to the performance of coatings and comparative performance of controls in the studies is emphasized. Considering the obvious advantages of bare Nitinol surfaces for superelastic implants, details of their preparation are also outlined
Drastic influence of minor Fe or Co additions on the glass forming ability, martensitic transformations and mechanical properties of shape memory Zr–Cu–Al bulk metallic glass composites
No full textThe microstructure and mechanical properties of Zr48Cu48 − x Al4M x (M ≡ Fe or Co, x = 0, 0.5, 1 at.%) metallic glass (MG) composites are highly dependent on the amount of Fe or Co added as microalloying elements in the parent Zr48Cu48Al4 material. Addition of Fe and Co promotes the transformation from austenite to martensite during the course of nanoindentation or compression experiments, resulting in an enhancement of plasticity. However, the presence of Fe or Co also reduces the glass forming ability, ultimately causing a worsening of the mechanical properties. Owing to the interplay between these two effects, the compressive plasticity for alloys with x = 0.5 (5.5% in Zr48Cu47.5Al4Co0.5 and 6.2% in Zr48Cu47.5Al4Fe0.5) is considerably larger than for Zr48Cu48Al4 or the alloys with x = 1. Slight variations in the Young's modulus (around 5–10%) and significant changes in the yield stress (up to 25%) are also observed depending on the composition. The different microstructural factors that have an influence on the mechanical behavior of these composites are investigated in detail: (i) co-existence of amorphous and crystalline phases in the as-cast state, (ii) nature of the crystalline phases (austenite versus martensite content), and (iii) propensity for the austenite to undergo a mechanically-driven martensitic transformation during plastic deformation. Evidence for intragranular nanotwins likely generated in the course of the austenite–martensite transformation is provided by transmission electron microscopy. Our results reveal that fine-tuning of the composition of the Zr–Cu–Al–(Fe,Co) system is crucial in order to optimize the mechanical performance of these bulk MG composites, to make them suitable materials for structural applications
Precipitation and austenite reversion behavior of a maraging steel produced by selective laser melting
No full textMaterials produced by selective laser melting (SLM) experience a thermal history that is markedly different from that encountered by conventionally produced materials. In particular, a very high cooling rate from the melt is combined with cyclical reheating upon deposition of subsequent layers. Using atom-probe tomography (APT), we investigated how this nonconventional thermal history influences the phase-transformation behavior of maraging steels (Fe–18Ni–9Co–3.4Mo–1.2Ti) produced by SLM. We found that despite the “intrinsic heat treatment” and the known propensity of maraging steels for rapid clustering and precipitation, the material does not show any sign of phase transformation in the as-produced state. Upon aging, three different types of precipitates, namely (Fe,Ni,Co)3(Ti,Mo), (Fe,Ni,Co)3(Mo,Ti), and (Fe,Ni,Co)7Mo6 (µ phase), were observed as well as martensite-to-austenite reversion around regions of the retained austenite. The concentration of the newly formed phases as quantified by APT closely matches thermodynamic equilibrium calculations.status: Publishe
Building intelligent credit-risk evaluation systems using neural network rule extraction and decision tables
No full textTable of contentsNeo-classical reengineering: Returning to the promise of process in the post-Internet economyM. De Kegel and M. McDonaldTowards an integrative framework for software architectureR. Maes and G. DedeneComponent based development. From dinosaurs to small, adaptive, co-operating, replaceable creaturesG. Van Humbeeck, J. MerckxSeparating Business Process Aspects from Business Object behaviourM. SnoeckCOSMIC-FFP and MERODE: Applying the Next Generation Function Points to Object Oriented Enterprise ModelsG. PoelsOn the use of Jackson Structured Programming (JSP) for the structured design of XSL TransformationsG. DedeneRuling the business: about Business Rules, decision tables and Intelligent AgentsJ. VanthienenBuilding intelligent credit-risk evaluation systems using neural network rule extraction and decision tablesB. Baesens, R. Setiono, C. Mues, S. Viaene and J. VanthienenWeb service description, advertising and discovery: WSDL and beyondW. LemahieuDeveloping enterprise architecture: the case of KBC InsuranceF. Pieck, S. Viaene and G. Deden
A probabilistic model for martensitic avalanches
No full textWe present a probabilistic model for the description of martensitic avalanches. Our approach to the analysis of the model is based on an associated general branching random walk process. Comparisons are reported for numerical and analytical solutions and experimental observations
Shape memory materials: State of the art and requirements for future applications
No full textNiTi is only one of many alloy systems that exhibit the shape memory effect. The reason of his success is only the fact that it is the best in many aspects. His large market share created a significant price reduction so that in combination with its good properties, it became a preferential alloy even when compared with Cu-based alloys. Moreover NiTi alloys can be easily tuned to optimal performance by applying the proper combination of deformation and heat treatments. Its most successful applications are related to medical devices.status: Publishe
Damping Properties of Shape Memory Alloys During Phase Transformation
No full textA high damping capacity is considered as one of the important functional properties of shape memory alloys. Those properties are related to a thermoelastic martensitic transformation. As a consequence of this transformation, the internal friction or damping can be investigated for three different states : 1. during thermal transformation cycling, 2. during martensite induced strain cycling at constant temperature, 3. in the martensitic state. The difficulty of formulating a unified theory to those three approaches is related to the complexity of the microstructure. Phase boundaries, dislocations, precipitates, impurities and point-defects interact strongly with each other, thereby influencing the macroscopic observation. However, improved models have been recently formulated to describe the observed internal friction during transformation, taking into account the change in defect mobility. This has also lead to a new approach of analyzing the observed damping in an amplitude dependent and amplitude independent part. Special attention is also given to superelastic damping with the aim of improving earthquake resistance of constructions, concentrating reversible hysteretic behaviour in detailed regions of the structure. Moreover, new relations between other functional properties and the internal friction of the martensite have been established. This paper will describe the recent findings, the importance of the results, fundamentally and practically, concurrently pointing to some interesting topics for further research
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