121 research outputs found
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
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
INTERACTIE VAN PARKINE MET AMBRA1 INDUCEERT MITOFAGIE
No full textPD is the second most prevalent neurodegenerative disorder, causing a va riety of disabling motor and non-motor problems. Mutations in PARK2, the gene encoding the cytosolic E3 ubiquitin ligase Parkin, are a major cau se of autosomal recessive PD, probably through a loss-of-function mechan ism. Recent work has shown that Parkin translocates from the cytosol to depolarized mitochondria and induces their autophagic removal (mitophagy ). Parkin may thus protect cells by mediating the selective removal of d ysfunctional mitochondria that would otherwise lead to enhanced oxidativ e stress and trigger apoptosis. However, the molecular mechanisms underl ying Parkin-mediated mitophagy are poorly understood. Here, we investiga ted whether Parkin interacts with autophagy-regulating proteins. We puri fied Parkin and associated proteins from HEK293 cells using tandem affin ity purification and identified the Parkin interactors using mass spectr ometry. We identified the autophagy-promoting protein Ambra1 as a Parkin interactor. Ambra1 activates autophagy in the central nervous system by stimulating the activity of the class III phosphatidylinositol 3-kinase (PI3K) complex that is essential for the formation of new phagophores.& nbsp;We found Ambra1, like Parkin, to be widely expressed in adult mouse brain, including midbrain dopaminergic neurons. Endogenous Parkin and A mbra1 co-immunoprecipitated from HEK293 cells, SH-SY5Y cells and adult m ouse brain. We found no evidence for ubiquitination of Ambra1 by Parkin. The interaction of endogenous Parkin and Ambra1 strongly increased upon prolonged mitochondrial depolarization. Ambra1 was not required for Par kin translocation to depolarized mitochondria, but was critically import ant for subsequent mitochondrial clearance. In particular, Ambra1 was re cruited to perinuclear clusters of depolarized mitochondria and activate d class III PI3K in their immediate vicinity. Our findings sugg est a novel mechanism that facilitates Parkin-induced engulfment of mito chondria by autophagosomes. Rather than merely attracting pre-existing p hagophores via ubiquitination of outer mitochondrial membrane proteins a nd recruitment of adaptors such as p62, Parkin actually stimulates the p erimitochondrial nucleation of new phagophores through recruitment of Am bra1. After incorporation of LC3, these locally formed new phagophores m ay then become tethered to ubiquitinated mitochondria via adaptors like p62. Ambra1 thus enhances the efficiency of Parkin-mediated mitophagy.<b r>In conclusion, these data identify interaction of Parkin with Ambra1 a s a key mechanism for induction of the final clearance step of Parkin-me diated mitophagy.status: Publishe
Comments on the interpretation of differential scanning calorimetry results for thermoelastic martensitic transformations: athermal versus thermally activated kinetics
No full textIn a previous article Van Humbeeck and Planes have made a number of criticisms of the authors` recent paper concerning the interpretation of the results obtained by Differential Scanning Calorimetry (DSC) from the Martensitic Transformation of Cu-Al-Ni-Mn-B alloys. Although the martensitic transformation of these shape memory alloys is generally classified as athermal, it has been confirmed that the capacity of the alloys to undergo a more complete thermoelastic transformation (i.e. better reversibility of the transformation) increased with the Mn content. This behavior has been explained by interpreting the DSC results obtained during thermal cycling in terms of a thermally activated mechanism controlling the direct and reverse transformations. When the heating rate increases during the reverse transformation the DSC curves shift towards higher temperatures while they shift towards the lower temperatures when the cooling rate was increased during the direct transformation. Since the starting transformation temperatures (As, Ms) do not shift, Van Humbeeck and Planes state that there is no real peak shift and assume that the DCS experiments were carried out without taking into account the thermal lag effect between sample and cell. On the following line they deduce a time constant, {tau}, of 60 seconds because the peak maximum shifts. In fact the assumption made by Van Humbeeck and Planes is false.Peer Reviewe
Influence of carbon nanoparticle addition (and impurities) on selective laser melting of pure copper
No full textThe addition of 0.1 wt % carbon nanoparticles significantly improved the optical absorption and flowability of gas-atomized copper powder. This facilitated selective laser melting (SLM) by reducing the required laser energy density to obtain 98% dense parts. Moreover, the carbon addition led to an in situ de-oxidation of the copper parts during the SLM process. The properties of the as-built copper parts were limited to a tensile strength of 125 MPa, a ductility of 3%, and an electrical conductivity of 22.7 × 106 S/m, despite the advantageous effect of carbon on the powder characteristics and SLM behavior. The modest mechanical properties were associated with the segregation of carbon nanoparticles and other impurities, such as phosphorus and oxygen along grain boundaries of epitaxially grown grains. Whereas, the low electrical conductivity was mainly attributed to the phosphorus impurity in solid-solution with copper
Kris Humbeeck: 'Animal garden for today's children: third series'. (Vertaling van 'Diergaarde voor kinderen van nu: derde reeks')
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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
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 calibration study of the dupont dsc 910 module
No full textIn this paper a calibration study of the Dupont 910 DSC module is presented. According to our view of the cell construction, this type of calorimeter combines the advantages and disadvantages of a DTA and DSC cell. It was found that the calibration constant E is independent of temperature (as it should be for any DSC cell) but is dependent on the heating rate and the mass or the total absolute heat exchange by the sample.status: Publishe
Stabilization and two-way shape memory effect in Cu-Al-Ni single crystals
No full textThe two-way shape memory effect (TWME) induced by stabilization of the martensite phase during aging has been studied in Cu-13.4 Al-4.0 Ni (mass pet) single crystals. The influence of the degree of long-range order on the transformation has been determined by using different heat treatments. The transformation temperatures are strongly influenced by the degree of order in the austenite: annealing from above or below the second neighbor L2(1) ordering temperature changes the M-s by more than 100 degrees C. It has been established that the diffusion in the austenite as well as in the martensite phase is considerably slower in this alloy than in other Cu-based ones, due to the presence of Ni. The obtained TWME has a similar efficiency as when other more complex thermomechanical trainings are made. In this alloy, the TWME by stabilization is not complete, in contrast to that in Cu-Zn-Al single crystals.status: Publishe
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