2,355 research outputs found
A Transfer Report on the Development of a Framework to Evaluate Search Interfaces for their Support of Different User Types and Search Tactics
No full textAs the understanding of search systems, user needs and seeking strategies is developing, the design of search user interfaces is evolving to support more complicated and exploratory forms of search. With the design of new search features that enable these richer modes of exploration, comes the need to better understand the support they provide. In this report a new evaluation framework is presented that analyses search features for how they a) contribute to an overall interface, b) allow users to carry out different search tactics, and c) support different types of users and their needs. The novel contributions of the framework improve on some of the limitations of typical user studies, and allow search systems to be systematically analysed in much more detail and in much less time. The presented evaluation framework is then validated in three ways. First the validity of the models used as the building blocks of the framework are investigated through related work. Second the method of integrating these building-block models is validated and strengthened by consensus of expert opinion. Third, the overall approach is validated by comparing its analyses to the results of previously carried out user studies. The validation process has shown both the value of the framework and identified areas of future work that should be addressed for the framework to be completed. This report concludes with the set of contributions that the framework makes, and why the remaining work will be challenging, but critical to the final design
Molecular Dynamics Simulation Study of Interaction between Model Rough Hydrophobic Surfaces
No full textWe study some aspects of hydrophobic interaction between molecular rough and flexible model surfaces. The model we use in this work is based on a model we used previously (Eun, C.; Berkowitz, M. L. J. Phys. Chem. B 2009, 113, 13222-13228), when we studied the interaction between model patches of lipid membranes. Our original model consisted of two graphene plates with attached polar headgroups; the plates were immersed in a water bath. The interaction between such plates can be considered as an example of a hydrophilic interaction. In the present work we modify our previous model by removing the charge from the zwitterionic headgroups. As a result of this procedure, the plate character changes; it becomes hydrophobic. By separating the total interaction (or potential of mean force, PMF) between plates into the direct and the water-mediated interactions we observe that the latter changes from repulsive to attractive, clearly emphasizing the important role of water as a medium. We also investigate the effect of roughness and flexibility of the headgroups on the interaction between plates and observe that roughness enhances the character of the hydrophobic interaction. The presence of a dewetting transition in a confined space between charge-removed plates confirms that the interaction between plates is strongly hydrophobic. In addition, we notice that there is a shallow local minimum in the PMF in case of charge-removed plates. We find that this minimum is associated with the configurational changes that flexible headgroups undergo, as the two plates are brought together
A Validated Framework for Measuring Interface Support for Interactive Information Seeking
No full textIn this paper we present the validation of an evaluation framework that models the support provided by search systems for different types of user and their expected types of seeking behavior. Factors determining the types of users include previous knowledge and goals. After an overview is presented, the framework is validated in two ways. First, the novel integration of the two existing information-seeking models used in the framework is validated by the correlation of multiple expert and novice analysis. Second, the framework is validated against the results produced by two separated user studies. Further, the refinements made by the first validation technique are shown to increase the accuracy of the framework through the second technique. The successful validation process has shown that the framework can identify both strong and weak areas of search interface design in only a few hours. The results produced can be used to either revise and strengthen designs or inform the structure of a user study
Self Healing Alumina Composite with MAX-phase Particles
No full textThe use of Ti2AlC MAX-phase as healing particles to heal surface cracks in alumina is studied. Pure Ti2AlC and the alumina composite (Al2O3-20 vol. % Ti2AlC) were synthesised by Spark Plasma Sintering. The kinetics of the oxidation of MAX-phase into rutile and alumina, were studied via Thermo- Gravimetric Differential Thermal Analysis. The strength recovery after crack damage, by high temperature oxidation of the healing particles, was measured using 4-point bending. Through thermal analysis it was observed that healing can be achieved below 1000 °C with the formation of rutile at 800 °C and alumina at 900 °C. The strength recovered after healing was quantified systematically as function of temperature and time at 800, 900 and 1000 °C for 0.25, 1 and 4 and 16 hours. The strength of the composite was reduced by about 50 % from 402 MPa ±35 to 229 MPa ±14 when a crack of 100 μm long was introduced by indentation. After healing at 1000 °C for 15 minutes, the strength of the damaged material increased to about 95 % of the original non-cracked composite. After 1 hour at this same temperature the strength increased to about 98 % of the original material. When healing is performed at 900 and 800 °C, the time needed for full strength recovery increased to 4 and 16 hours respectively. Moreover, embedding Ti2AlC particles in alumina enhances alumina’s resistance to crack propagation. A model developed for filling of a crack gap revealed that: To fill a crack of 1 μm wide, the minimum required MAX-phase content is 5 % and the minimum MAX-phase particle diameter is 3.6 μm.Mechanical, Maritime and Materials EngineeringMaterials Science and Engineerin
Point contact abrasive wear behavior of MAX phase materials
No full textThe room temperature abrasive wear behavior of three selected MAX phases, Ti3SiC2, solution strengthened Ti2.7Zr0.3SiC2 and Cr2AlC, is investigated by low velocity scratch testing using a diamond conical indentor with a final radius of 100 μm and a cone angle of 120° and applied loads of up to 20 N. All three materials showed a relatively low wear resistance in comparison to most engineering ceramics such as Al2O3, Si3N4 and SiC. For all three materials, the wear rate scaled more or less linearly with the applied load. The softer Ti3SiC2 with a hardness of 2.8 GPa showed the lowest wear resistance with extensive ploughing and grain breakout damage, both within and outside the direct wear track, in particular at the highest load. The hardest material, Ti2.7Zr0.3SiC2, with a hardness of 7.3 GPa, showed a 5 times better wear resistance. The Cr2AlC with a hardness of 4.8 GPa showed a wear resistance equal to or even better than that of the Ti2.7Zr0.3SiC2. The wear mechanism depends on the applied load and the microstructure of the MAX phase materials tested. For the Ti3SiC2 sample, a quasi-plastic deformation behavior occurs below a point load of 10 N, resulting in grain bending, kink band formation and delamination, grain de-cohesion, as well as trans-and intra-granular fracture near the scratch groove. At this load, the Ti2.7Zr0.3SiC2 and Cr2AlC MAX samples display plastic ploughing, grain boundary cracks and material dislodgments.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.(OLD) MSE-1Delft Aerospace Structures and Materials LaboratoryNovel Aerospace Material
Correction: Pius et al. Effects of Aging on Osteosynthesis at Bone–Implant Interfaces. <i>Biomolecules</i> 2024, <i>14</i>, 52
No full textMax L. Lee was not included as an author in the original publication [...
An analytical inspection framework for evaluating the search tactics and user profiles supported by information seeking interfaces
No full textSearching is something we do everyday both in digital and physical environments. Whether we are searching for books in a library or information on the web, search is becoming increasingly important. For many years, however, the standard for search in software has been to provide a keyword search box that has, over time, been embellished with query suggestions, Boolean operators, and interactive feedback. More recent research has focused on designing search interfaces that better support exploration and learning. Consequently, the aim of this research has been to develop a framework that can reveal to designers how well their search interfaces support different styles of searching behaviour.The primary contribution of this research has been to develop a usability evaluation method, in the form of a lightweight analytical inspection framework, that can assess both search designs and fully implemented systems. The framework, called Sii, provides three types of analyses: 1) an analysis of the amount of support the different features of a design provide; 2) an analysis of the amount of support provided for 32 known search tactics; and 3) an analysis of the amount of support provided for 16 different searcher profiles, such as those who are finding, browsing, exploring, and learning. The design of the framework was validated by six independent judges, and the results were positively correlated against the results of empirical user studies. Further, early investigations showed that Sii has a learning curve that begins at around one and a half hours, and, when using identical analysis results, different evaluators produce similar design revisions.For Search experts, building interfaces for their systems, Sii provides a Human-Computer Interaction evaluation method that addresses searcher needs rather than system optimisation. For Human-Computer Interaction experts, designing novel interfaces that provide search functions, Sii provides the opportunity to assess designs using the knowledge and theories generated by the Information Seeking community. While the research reported here is under controlled environments, future work is planned that will investigate the use of Sii by independent practitioners on their own projects
Synthesis, crystal structure, microstructure and mechanical properties of (Ti1-Zr )3SiC2 MAX phase solid solutions
No full textAlmost pure (Ti1-xZrx)3SiC2 MAX phase solid solutions with x ranging up to 0.17 were synthesized at temperatures in the range of 1450–1750 °C with reactive Spark Plasma Sintering (SPS). The zirconium partially replaces the M-element titanium of the Ti3SiC2 MAX phase up to x equals 0.17. The lattice parameters of the hexagonal (Ti1-xZrx)3SiC2 MAX phase are determined with X-ray diffraction using Rietveld refinement and show an anisotropic lattice expansion upon Zr insertion into Ti3SiC2. This observation is in very good agreement with density functional theory calculations where the deviation between the measured and calculated lattice parameter is less than 1%. The predicted elastic modulus reduction is only 4%. This behavior can be rationalized by considering the electronic structure, where only minute changes are observable as Zr is incorporated into Ti3SiC2. The measured nanohardness of the synthesized (Ti1-xZrx)3SiC2 MAX phase increases from 12.7 ± 1 GPa for Ti3SiC2 to 16.3 ± 1.1 GPa when x is raised from 0 to 0.17 due to an increasing amount of accompanying Ti1-yZryC. The elastic moduli of (Ti1-xZrx)3SiC2 solid solutions measured by an ultrasonic pulse-echo method (325–354 GPa) are in good agreement with the predicted elastic moduli (357–342 GPa).Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.(OLD) MSE-1Novel Aerospace Material
On the approximation of the elastica functional in radial symmetry
No full textWe prove a result concerning the approximation of the elastica functional with a sequence of second order functionals, under radial symmetry assumptions. This theorem is strictly related to a conjecture of De Giorgi [8].
Received: 26 July 2004, Accepted: 19 October 2004, Published online: 22 December 2004
The first author is grateful to Maurizio Paolini for useful discussions.
The second author gratefully acknowledges the hospitality and the support of the Max Planck Institute for Gravitational Physics in Golm, where this paper was completed
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