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Fuentes C.A.,Catholic University of Leuven | Tran L.Q.N.,Catholic University of Leuven | Van Hellemont M.,GROUP T Leuven Engineering College | Janssens V.,Catholic University of Leuven | And 3 more authors.
Colloids and Surfaces A: Physicochemical and Engineering Aspects | Year: 2013

Systematic experimental results describing the dynamic wetting properties of bamboo fibres were analysed by applying the molecular-kinetic theory of wetting. Results suggest that the bamboo fibre surface represents a well-defined system for wetting analysis. The surface free energy components were calculated according to the acid-base theory. These values were then used to calculate the theoretical work of adhesion, spreading coefficient, wetting tension, and interfacial energy. The wetting behaviour of various thermoplastic matrices (polypropylene, maleic anhydride-grafted polypropylene, polyvinylidene-fluoride, and polyethylene-terephthalate) was characterized. Surface chemical components were identified using XPS. Additionally, transverse 3-point bending tests and single fibre pull-out tests were performed. This integrated physical-chemical-mechanical approach was used to study the effect of adhesion on the mechanical strength of thermoplastic composites reinforced with bamboo, showing that increase in physical adhesion can explain the improved interfacial and longitudinal strength in bamboo polyvinylidene-fluoride (PVDF) composites compared to the other thermoplastic matrices used in this study. Surface energy components of bamboo fibres and PVDF were matched, resulting in an improvement of the physical adhesion. © 2012 Elsevier B.V.


Kellens K.,Catholic University of Leuven | Renaldi,Group T Leuven Engineering College | Dewulf W.,Catholic University of Leuven | Dewulf W.,Group T Leuven Engineering College | Duflou J.R.,Catholic University of Leuven
Glocalized Solutions for Sustainability in Manufacturing - Proceedings of the 18th CIRP International Conference on Life Cycle Engineering | Year: 2011

Manufacturing processes, as used for discrete part manufacturing, are responsible for a substantial part of the environmental impact of products, but are still poorly documented in terms of environmental footprint. This paper presents the first results of a data collection effort, allowing to assess the overall environmental impact of three types of Electrical Discharge Machining (EDM) processes: die sinking EDM, wire EDM and micro EDM. After the inventorisation of all process flows using the CO2PE!-methodology, a subsequent impact assessment analysis allows indentifying the most important contributors to the environmental impact of EDM. Finally some improvement potential is sketched.


Kellens K.,Catholic University of Leuven | Renaldi R.,Catholic University of Leuven | Dewulf W.,Catholic University of Leuven | Dewulf W.,Group T Leuven Engineering College | Duflou J.R.,Catholic University of Leuven
Leveraging Technology for a Sustainable World - Proceedings of the 19th CIRP Conference on Life Cycle Engineering | Year: 2012

Environmental analyses of standalone unit manufacturing processes as well as full process chains indicate improvement potential at machine tool architecture, process control as well as production planning level leading to lower environmental footprints of discrete part manufacturing processes. This paper presents a framework, illustrated by a case-study for laser cutting, to establish parametric environmental process models, for example to be used in simulation tools. Furthermore, the framework supports the development of generic LCI-datasets based on comparing and aggregating environmental analyses of a range of similar machine tools (several suppliers and machine tool capacities).


Zaman B.,Catholic University of Leuven | Vanden Abeele V.,GROUP T Leuven Engineering College
Proceedings of IDC2010: The 9th International Conference on Interaction Design and Children | Year: 2010

In this paper, we investigate the usefulness and feasibility of Laddering with young children in User eXperience evaluations. We start with a revision of theoretical literature and guidelines. Developmental literature suggests that children aged two to seven years old have the cognitive capabilities to perform as Laddering interviewees. Next, we put these findings to the test via a practical case. The results of our case study demonstrate that only the older children, aged five years and older, were able to construct meaningful ladders. As for the type of ladders created, our results are in line with literature; children are inclined to attribute external reasons to product preferences rather than internal reasons, and consequently create ladders of attributes and consequences, not reaching for values. Copyright 2010 ACM.


Geurts L.,Group T Leuven Engineering College | Geurts L.,Catholic University of Leuven | Abeele V.V.,Group T Leuven Engineering College | Abeele V.V.,Catholic University of Leuven | And 5 more authors.
Proceedings of the 5th International Conference on Tangible Embedded and Embodied Interaction, TEI'11 | Year: 2011

With the advent of computer games involving the movement of the player's whole body or body parts, an opportunity arises to develop games for people with motor disabilities. In this paper we present four minigames developed for people suffering from spasticity and loss of motor control. We thereby focus on the input devices, sensor signal processing and mapping of players' actions on events in the game. In order to adapt the game to the player's motor skills and goals, specific attention should be paid to calibration procedures and adjustable parameters. We illustrate how this can be done and simultaneously, we demonstrate the feasibility for the development of digital games for physical therapy with currently available commercial input devices. © 2011 ACM.


Kellens K.,Catholic University of Leuven | Renaldi R.,Catholic University of Leuven | Dewulf W.,Catholic University of Leuven | Dewulf W.,Group T Leuven Engineering College | And 2 more authors.
Rapid Prototyping Journal | Year: 2014

Purpose - This paper aims to present parametric models to estimate the environmental footprint of the selective laser sintering (SLS)' production phase, covering energy and resource consumption as well as process emissions. Additive manufacturing processes such as (SLS) are often considered to be more sustainable then conventional manufacturing methods. However, quantitative analyses of the environmental impact of these processes are still limited and mainly focus on energy consumption.Design/methodology/approach - The required Life Cycle Inventory data are collected using the CO2PE! - Methodology, including time, power, consumables and emission studies. Multiple linear regression analyses have been applied to investigate the interrelationships between product design features on the one hand and production time (energy and resource consumption) on the other hand.Findings - The proposed parametric process models provide accurate estimations of the environmental footprint of SLS processes based on two design features, build height and volume, and help to identify and quantify measures for significant impact reduction of both involved products and the supporting machine tools.Practical implications - The gained environmental insight can be used as input for ecodesign activities, as well as environmental comparison of alternative manufacturing process plans.Originality/value - This article aims to overcome the current lack of environmental impact models, covering energy and resource consumption as well as process emissions for SLS processes. © Emerald Group Publishing Limited.


Kellens K.,Catholic University of Leuven | Yasa E.,Catholic University of Leuven | Renaldi,Catholic University of Leuven | Dewulf W.,Group T Leuven Engineering College | And 2 more authors.
22nd Annual International Solid Freeform Fabrication Symposium - An Additive Manufacturing Conference, SFF 2011 | Year: 2011

Manufacturing processes, as used for discrete part manufacturing, are responsible for a substantial part of the environmental impact of products, but are still poorly documented in terms of their environmental footprint. The lack of thorough analysis of manufacturing processes has as consequence that optimization opportunities are often not recognized and that improved machine tool design in terms of ecological footprint has only been targeted for a few common processes. Additive manufacturing processes such as Selective Laser Sintering (SLS) and Selective Laser Melting (SLM) allow near-net shape manufacturing of complex work pieces. Consequently, they inherently offer opportunities for minimum-waste and sustainable manufacturing. Nevertheless, powder production, energy consumption as well as powder losses are important and not always optimized environmental impact drivers of SLS and SLM. This paper presents the results of a data collection effort, allowing to assess the overall environmental impact of these processes using the methodology of the CO 2PE! (Cooperative Effort on Process Emissions in Manufacturing) initiative. Based on the collected LCI data, a subsequent impact assessment analysis allows indentifying the most important contributors to the environmental impact of SLS/SLM. Next to the electricity consumption, the consumption of inert gasses proves to be an important cause of environmental impact. Finally, the paper sketches the improvement potential for SLS/SLM on machine tool as well as system level.


Duflou J.R.,Catholic University of Leuven | Kellens K.,Catholic University of Leuven | Renaldi,Catholic University of Leuven | Renaldi,Group T Leuven Engineering College | And 2 more authors.
Key Engineering Materials | Year: 2011

This paper presents a view on environmental improvement potential of sheet metal working processes at unit process as well as system level. First, results and impact reducing measures for two case studies at unit process level are included. Furthermore impact reduction opportunities at system level are sketched and exergy metrics are briefly discussed. © (2011) Trans Tech Publications.


Paraskevas D.,Catholic University of Leuven | Kellens K.,Catholic University of Leuven | Dewulf W.,Catholic University of Leuven | Dewulf W.,Group T Leuven Engineering College | Duflou J.R.,Catholic University of Leuven
Journal of Cleaner Production | Year: 2015

The uncontrolled mixing of metals and their alloys during the different life cycle phases, combined with the melt purification constraints during remelting, pose great challenges during their end-of-life (EoL) treatment. In practice, open-loop recycling is typical and more common for metals than closed-loop recycling; especially in the case of aluminium, the industry operates in a cascade recycling approach. Associated with open-loop recycling are various types of material losses; loss of original functional quality, dissipation of scarce resources and the final need for dilution of the resulting metal impurities with primary materials. Thus, an environmental assessment tool is presented within this paper, aiming to support decision making related to the sustainable management of metal resources during secondary aluminium production. A material blending model aims at the minimization of the above mentioned losses in order to meet the product quality requirements. The goal of the study is threefold: i) to assess the environmental impact calculation of aluminium recycling, ii) to express, quantify and integrate dilution and quality losses into Life Cycle Assessment (LCA) studies, and iii) to determine the optimum material input for the recycling process from an environmental perspective. Different recycling options or strategies can be evaluated and compared based on avoided environmental impact. Case studies focusing on major post-consumer scrap streams are used to illustrate application areas and highlight the importance of altering and optimizing the raw material input. Finally, policy issues and opportunities for environmentally conscious metal management are discussed. © 2014 Elsevier Ltd. All rights reserved.


Vanden Abeele V.,GROUP T Leuven Engineering College | De Schutter B.,GROUP T Leuven Engineering College
Personal and Ubiquitous Computing | Year: 2010

We report on the design process and the design rationales of a physical mini-game, to be played by seniors and youngsters. First, we explain that we seek enactive interaction, rather than physical action. Next, we elaborate on how competition correlates with social interaction, relying on FIRO theory. Then, we analyze how the sensor technology within the WiiMote affords acceleration. Via an evaluation of existing physical mini-games, seniors and youngsters empirically verify these three design rationales on enactive interaction, competition and acceleration. We conclude that these rationales result in ease-of-use, equality-in-ease-of-use and visibility-of-player-action, which in turn stimulate competition and consequently intergenerational play. Finally, we present the design and user evaluation of our physical mini-game, designed in accordance with these rationales. © 2009 Springer-Verlag London Limited.

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