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University of Twente Publications (51,436 recursos)
University of Twente Repository provides publications of UT scientific staff, in many cases full text and publicly available.

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Mostrando recursos 1 - 20 de 10,064

1. Antibacterial textiles - Bhaskara, Usha Rashmi

2. Influence of ground tyre rubber devulcanisates on morphology and properties of tread tyre formulation - Dayang Habibah, A.I.H.; Saiwari, Sitisayidah; Dierkes, Wilma; Noordermeer, Jacques W.M.
Extensive research on recycling processes, in particular for waste tyre material, is necessary due to increasing raw material costs, diminishing resources and growing awareness of environmental issues. One of the preferred methods is devulcanisation, in which only sulphur cross-links are broken, while the polymer chains remain intact. In this study, optimised processing conditions for the devulcanisation of whole passenger car tyres using diphenyldisulphide (DPDS) as a devulcanisation aid were applied. The devulcanised ground tyre rubber (D-GTR) obtained from the process was blended on top of the original tyre tread formulation at different concentrations. The cure characteristics and mechanical properties of...

3. The water footprint in Morocco - Schyns, J.F.; Hoekstra, A.Y.

4. Water footprint assessment for Latin America and the Caribbean - Mekonnen, M.M.; Pahlow, M.; Aldaya, M.M.; Zarate, E.; Hoekstra, A.Y.

5. Opening the "black-box" of place-based leadership. Deconstructing the role of university senior leadership in city/regional development - Karlsen, James; Benneworth, Paul; Pinheiro, Rómulo

6. The Development of an IT Governance Maturity Model for Hard and Soft Governance - Smits, Daniel; Hillegersberg, Jos van
To be able to advance in maturity, organizations should pay attention to both the hard and soft aspects of governance. Current literature on IT governance (ITG) is mostly directed at the hard part of governance, focusing on structures and processes. The soft part of governance is related to social aspects like human behavior and organizational culture. This part of governance receives much less attention in the literature. The goal of the study is to design a model which covers hard and soft governance and can be used as a basis for a maturity model (MM). We adopted a research method...

7. Individueel roosteren in de ploeg - Goudswaard, Anneke; Groen, Sam; Leede, Jan de; Vos, Peter

8. In situ ellipsometry studies on swelling of thin polymer films: A review - Ogieglo, W.; Wormeester, H.; Eichhorn, K.-J.; Wessling, M.; Benes, N.E.
The properties of a thin polymer film can be significantly affected by the presence of a penetrant. This can have potential implications for many technological applications, suchas protective and functional coatings, sensors, microelectronics, surface modification andmembrane separations. In situ ellipsometry is a powerful technique for the characteriza-tion of a film in contact with a penetrant. The main advantages of ellipsometry includethe very high precision and accuracy of this technique, combined with the fact that it isnon-intrusive. Recent advances in the speed and automation of the technique have furtherexpanded its application.This article provides an overview of the research that has been...

9. Optical anisotropy, molecular orientations, and internal stresses in thin sulfonated poly(ether ether ketone) films - Koziara, B.T.; Nijmeijer, D.C.; Benes, N.E.
The thickness, the refractive index, and the optical anisotropy of thin sulfonated poly(ether ether ketone) films, prepared by spin-coating or solvent deposition, have been investigated with spectroscopic ellipsometry. For not too high polymer concentrations (B5 wt%) and not too low spin speeds (C2000 rpm), the thicknesses of the films agree well with the scaling predicted by the model of Meyerhofer, when methanol or ethanol are used as solvent. The films exhibit uniaxial optical anisotropy with a higher in-plane refractive index, indicating a preferred orientation of the polymer chains in this in-plane direction. The radial shear forces that occur during the...

10. Creep behaviour of perovskite-type oxides Ba0.5Sr0.5(Co0.8Fe0.2)1−xZrxO3−δ - Stournari, V.; Donkelaar, S.F.P. ten; Malzbender, J.; Beck, T.; Singheiser, L.; Bouwmeester, H.J.M.
Compressive creep tests have been performed on perovskite-type oxides Ba0.5Sr0.5(Co0.8Fe0.2)1–xZrxO3−δ (BSCF-Z100·x), where x = 0.01, 0.03, 0.05 and 0.1, for the use as oxygen transport membrane, in air at 800–950 °C and at nominal stresses of 30 MPa and 63 MPa. X-ray diffraction and microstructural observations support a solid solubility limit of ZrO2 between 0.03 < x < 0.05. Evidence is found for the formation of (Ba,Sr)ZrO3 secondary phases in grain boundaries at compositions beyond this limit. Zr substitution of (Co,Fe) in BSCF is found to suppress grain growth significantly, which is attributed to a solute and/or particle drag (Zener...

11. Pt nanoparticle modified single walled carbon nanotube network electrodes for electrocatalysis: control of the specific surface area over three orders of magnitude - Miller, T.S.; Sansuk, S.; Lai, S.C.S.; Macpherson, J.V.; Unwin, P.R.
The electrodeposition of Pt nanoparticles (NPs) on two-dimensional single walled carbon nanotube (SWNT) network electrodes is investigated as a means of tailoring electrode surfaces with a well-defined amount of electrocatalytic material. Both Pt NP deposition and electrocatalytic studies are undertaken using the microcapillary electrochemical method (MCEM), enabling multiple microscale measurements to be performed quickly and easily on the same SWNT sample. Using this approach, Pt catalysts with high specific surface areas relative to the geometric electrode area (defined by the meniscus contact of the MCEM probe with the Si/SiO2 substrate bearing the SWNT network) can be controlled precisely over three...

12. Circulating tumor cells before and during follow-up after breast cancer surgery - Dalum, Guus van; Stam, Gert Jan; Tibbe, Arjan G.J.; Franken, Bas; Mastboom, Walter J.B.; Vermes, Ivan; Groot, Marco R. de; Terstappen, Leon W.M.M.
The presence of circulating tumor cells (CTC) is an independent prognostic factor for progression-free and overall survival for patients with metastatic and newly diagnosed breast cancer. The present study was undertaken to explore whether the presence of CTC before and during follow-up after surgery is associated with recurrence free survival (RFS) and overall survival (OS). In a prospective single center study, CTC were enumerated with the CellSearch system in 30 ml of peripheral blood of 403 stage I-III patients before undergoing surgery for breast cancer (A) and if available 1 week after surgery (B), after adjuvant chemo- and/or radiotherapy or...

13. Vesicular Amine Transporter VMAT2 in the Rat Ileum: from Principal Mechanism to Clinical Applications - Stoyanova, I.I.
Besides the role of a classical neurotransmitter, histamine plays a key role in the immune/inflammatory processes in the gastrointestinal tract. Specific transport proteins pack the amine neurotransmitters into vesicles so that their release can be regulated by neural activity. Recently, two vesicular amine transporters (VMAT1 and VMAT2), essential components of monoaminergic neurons and endocrine cells were identified. In our study we investigated VMAT2 distribution in the rat distal ileum using an immunocytochemical technique. VMAT2- immunreactivity was found in neurons of the submucosal and myentericplexuses, as well as in a dense network of nerve fibers.VMAT2-containing varicosities were numerous in the circular muscle...

14. What determines the impact of context on sequential action? - Ruitenberg, Marit F.L.; Verwey, Willem B.; Abrahamse, Elger L.
In the current study we build on earlier observations that memory-based sequential action is better in the original learning context than in other contexts. We examined whether changes in the perceptual context have differential impact across distinct processing phases (preparation versus execution of a motor chunk) within an ongoing movement sequence. Participants were trained on two discrete keying sequences, each of which was systematically presented in its own unique color during a practice session with either limited or extended practice. In a subsequent test session, sequences were performed with the same, with reversed, and with completely novel sequence-specific colors. The...

15. Internet skill levels increase, but gaps widen: a longitudinal cross-sectional analysis (2010–2013) among the Dutch population - Deursen, Alexander J.A.M. van; Dijk, Jan A.G.M. van
In the current contribution, we investigated how (1) the levels of operational, formal, information, and strategic internet skills changed between 2010 and 2013, and how (2) the observed skill patterns differ across gender, age, and education. All internet skills are measured among representative samples of the Dutch population in 2010, 2011, 2012, and 2013. Cross-sectional data are repeated to consider patterns of change at the aggregate level. The levels of operational and formal internet skills increased most. Information internet skill remained more or less consistent, and strategic internet skills only revealed a very small increase. Policies related to internet skills...

16. The potential relevance of cognitive neuroscience for the development and use of technology-enhanced learning - Howard-Jones, Paul; Ott, Michela; Leeuwen, Theo H. van; Smedt, Bert
There is increasing interest in the application of cognitive neuroscience in educational thinking and practice, and here we review findings from neuroscience that demonstrate its potential relevance to technology-enhanced learning (TEL). First, we identify some of the issues in integrating neuroscientific concepts into TEL research. We caution against seeking prescriptive neuroscience solutions for TEL and emphasize the need, instead, to conceptualize TEL at several different levels of analysis (brain, mind and behaviour, including social behaviour). Our review emphasizes the possibility of combining TEL and neuroscience concepts in adaptive educational systems, and we consider instances of interdisciplinary technology-based interventions drawing on...

17. Attachment of β-cyclodextrin on cotton and influence of β-cyclodextrin on ester formation with BTCA on cotton - Bhaskara, U.R.; Tourrette, A.; Jocic, D.; Warmoeskerken, M.M.C.G.
Cotton was treated with β-cyclodextrin (BCD) and two derivatives of β-cyclodextrin (2-hydroxypropyl-β-cyclodextrin and monochlorotriazinyl-β-cyclodextrin) to assess the optimal type for fixation with cotton. The experimental results showed that treatment of cotton with BCD using the crosslinker BTCA resulted in higher fixation than the treatments with the other two derivatives. The concentration of BTCA used did not significantly influence the amount of fixation of BCD on cotton. FTIR-ATR spectroscopic analysis showed that the amount of ester formed on the fabric was influenced by the addition of BCD on cotton with BTCA in comparison to crosslinking of only BTCA with cotton. The...

18. Making operational strategies of asphalt teams explicit to reduce process variability - Bijleveld, F.R.; Miller, S.R.; Doree, A.G.
The on-site construction process undertaken by asphalt teams has a critical impact on pavement quality. Process improvement and learning require explicit information about the process. However, current on-site operational activities and key parameters are, in general, not systematically monitored and mapped. The lack of process information makes it difficult for contractors and asphalt teams to distinguish between good and poor practices and to improve. Although technologies to make the on-site process explicit are becoming widely available, their adoption has been slow. To overcome this knowledge gap regarding explicit information about the on-site construction process, this paper proposes a framework and...

19. Method-based learning: a case in the asphalt construction industry - Bijleveld, F.R.; Doree, A.G.
Traditional working practices in the construction industry rely heavily on the onsite experience and craftsmanship (the tacit knowledge) of operators and teams. This results in implicit learning and lengthy learning cycles. The aims of the research are to develop a deeper insight into construction processes and to instigate a change from current implicit learning to explicit method-based learning. To change to explicit method-based learning, Kolb’s experiential learning model was introduced into current practices and ‘explicating the process’ was added to this learning cycle. Further ‘reflective observation’ and ‘abstract conceptualization’ were incorporated explicitly during an actual road construction project using feedback...

20. Asset management perspective on the duration of public-private partnership contracts: cost-control trade-off? - Buiten, M. van; Hartmann, A.
The risk-incentive model of principal-agent relations and its extensions to infrastructural public-private partnerships outline the efficiency implications of parameters such as contract duration. The predominant focus on individual contracts is of limited use for public agencies that need to allocate their resources efficiently at the level of the entire asset network. This study therefore adopts an asset management perspective on the issue of contract duration in public-private partnership (PPP) contracts. In so doing, this research aims to add to the understanding of asset network level effects of important contractual parameters such as contract duration. Empirical material from the Netherlands illustrates...

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