759 research outputs found
Laser Interference Structuring Of A-gen For The Production Of Optical Diffraction Gratings
No full textIn this work, we study the pulsed laser crystallization of hydrogen-free amorphous germanium-nitrogen alloys (a-GeN). We discuss the role of nitrogen during phase transitions and the possible application of the resulting structure as an optical diffraction grating. The crystallized region results of pure microcrystalline germanium (μc-Ge). An indication that Ge-N bonds have broken and nitrogen outdiffused of the film is obtained from infrared spectroscopy and confirmed by Raman spectra. A pattern of alternating a-GeN and μc-Ge lines with a period of about 4 μm acts as an optical diffraction grating due to the difference in optical properties between the two materials, and the three dimensional surface profile, caused by N2 effusion, that is formed on the sample.762717722Lin, C.W., Tseng, C.H., Chang, T.K., Lin, C.W., Wang, W.T., Cheng, H.C., (2002) IEEE Electron Device Letters, 23, p. 133Hatanaka, Y., Niraula, M., Nakamura, A., Aoki, T., (2001) Applied Surface Science, 175, p. 462Toet, D., Smith, P.M., Sigmon, T.W., Thompson, M.O., (2000) Applied Physics Letters, 77, p. 307Lu, J.P., Mei, P., Fulks, R.T., Rahn, J., Ho, J., Wang, Y., Boyce, J.B., Street, R.A., (2000) Journal of Vaccum Science and Technology A- Vacuum Surfaces and Films, 18, p. 1823Sposili, R.S., Im, J.S., (1998) Applied Physics A- Materials Science and Processing, 67, p. 273Im, J.S., Sposili, R.S., Crowder, M.A., (1997) Applied Physics Letters, 70, p. 3434Sposili, R.S., Im, J.S., (1996) Applied Physics Letters, 69, p. 2864Sameshima, T., (1996) Applied Surface Science, 96 (8), p. 352Gosain, D.P., Machida, A., Usui, S., Arai, M., (2001) Polycrystalline Semiconductors IV Materials, Technologies and Large Area Electronics, 80-81, p. 169Gosain, D.P., Noguchi, T., Usui, S., (2000) Japanese Journal of Applied Physics Part 2 - Letters, 39, pp. L179Carey, P.G., Smith, P.M., Theiss, S.D., Wickboldt, P., (1999) Journal of Vacuum Science and Technology A - Vacuum Surfaces and Films, 17, p. 1946Mulato, M., Toet, D., Aichmayr, G., Santos, P.V., Chambouleyron, I., (1997) Appl. Phys. Lett., 70, p. 3570Aichmayr, G., Toet, D., Mulato, M., Santos, P.V., Spangenberg, A., Christiansen, S., Albrecht, M., Strunk, H.P., (1998) Phys. Stat. Sol. (a), 166, p. 659Aichmayr, G., Toet, D., Mulato, M., Santos, P.V., Spangenberg, A., Bergman, R.B., (1998) J. of Non-cryst. Solids, 227-230, p. 921Mulato, M., Toet, D., Aichmayr, G., Spangenberg, A., Santos, P.V., Chambouleyron, I., (1998) J. of Non-cryst. Solids, 227-230, p. 930Aichmayr, G., Toet, D., Mulato, M., Santos, P.V., Spangenberg, A., Christiansen, S., Albrecht, M., (1999) J. Appl. Phys., 85, p. 4010Gupta, V.V., Song, H.J., Im, J.S., (1997) Applied Physics Letters, 71, p. 99Heintze, M., Santos, P.V., Nebel, C.E., Stutzmann, M., (1994) Appl Phys. Lett., 64, p. 3148Mulato, M., Toet, D., Aichmayr, G., Santos, P.V., Chambouleyron, I., (1997) J. Appl. Phys., 82, p. 5159Zanatta, A.R., Chambouleyron, I., (1993) Phys. Rev. B, 48, p. 4560Swanepoel, R., (1983) J. Phys. E: Sci Instrum, 16, p. 1214Marques, F.C., Chambouleyron, I., Evangelisti, F., (1989) J. of Non-cryst. Solids, 114, p. 561Guanchua, C., Fangqing, Z., (1990) This Solid Films, 185, p. 231Marques, F.C., Lacerda, R.G., Lima Jr., M.M., Vilcarromero, J., (1995) Phys. Stat. Sol(b), 192, p. 549Zanatta, A.R., Chambouleyron, I., Santos, P.V., (1996) J. Appl. Phys., 79, p.
Image dataset for testing search and detection models
No full textThe TNO Human Factors Searchû2 image dataset consists of: a set of 44 high-resolution digital color images of different complex natural scenes, the ground truth corresponding to each of these scenes, and the results of psychophysical experiments on each of these images. The images in the Searchû2 dataset are a subset of a larger set that has been used in a visual search and detection experiment. Each scene (image) contains a single military vehicle that serves as a search target. The image dataset, an Excel file with the ground truth and observer data, and an extensive report describing the dataset are available on CD-ROM (requests by email to the first author). The dataset can be used to develop and validate digital metrics that compute the visual distinctness (contrast, conspicuity, or saliency) of targets in complex scenes, and models of human visual search and detection. The dataset has already been used in more than ten different studies in the literature, ranging from studies evaluating target detectability metrics to eye movement studies and attempts to model the human visual system. In addition to this work, eight other articles in this special section address the Searchû2 dataset
Short-pulse Laser Crystallization And Structuring Of A-ge
No full textLaser pulses in the nanosecond range were used to crystallize and structure (lateral dimensions ≤ 1 μm) amorphous germanium thin films. The crystallized material consists of grains with sizes increasing from about 5 to more than 20 nm as a function of laser pulse energy. Arrays of polycrystalline Ge dots (diameter ∼ 1 μm, period ∼ 5 μm) were produced by bringing three laser beams to interference on the sample surface. These arrays can be used as seeds for solid-phase growth of polycrystalline areas by thermal annealing below 450°C. © 1998 Elsevier Science B.V. All rights reserved.227-230PART 2930933Heintze, M., Santos, P.V., Nebel, C.E., Stutzmann, M., (1994) Appl. Phys. Lett., 64, p. 3148Chapman, R.L., Fan, J.C.C., Zeiger, H.J., Gale, R.P., (1980) Appl. Phys. Lett., 37, p. 292Césari, C., Nihoul, G., Marfaing, J., Marine, W., Mutaftschiev, B., (1985) Surf. Sci., 162, p. 724Sharma, R.K., Bansal, S.K., Nath, R., Srivastava, G.P., (1982) Thin Solid Films, 97, p. 1Mulato, M., Toet, D., Aichmayr, G., Santos, P.V., Chambouleyron, I., (1997) Appl. Phys. Lett., 70, p. 3570Mulato, M., Toet, D., Aichmayr, G., Santos, P.V., Chambouleyron, I., in printToet, D., Koopmans, B., Richards, B., Santos, P.V., Bergman, R., (1996) Proc. of the 23rd ICPS, p. 1123. , M. Sheffer, R. Zimermann (Eds.), World Scientific, SingaporeJellison G.E., Jr., Lowndes, D.H., (1987) Appl. Phys. Lett., 51, p. 352Anastassakis, E., Liarokapis, E., (1987) J. Appl. Phys., 62, p. 3346Campbell, I.H., Fauchet, P.M., (1986) Solid State Commun., 58, p. 739Richter, H., Wang, Z.P., Ley, L., (1981) Solid State Commun., 39, p. 62
Ground effect aerodynamics of racing cars
No full textWe review the progress made during the last thirty years on ground effect aerodynamics associated with race cars, in particular open wheel race cars. Ground effect aerodynamics of race cars is concerned with generating downforce, principally via low pressure on the surfaces nearest to the ground. The “ground effected” parts of an open wheeled car's aerodynamics are the most aerodynamically efficient and contribute less drag than that associated with, for example, an upper rear wing. Whilst drag reduction is an important part of the research, downforce generation plays a greater role in lap time reduction. Aerodynamics plays a vital role in determining speed and acceleration (including longitudinal acceleration but principally cornering acceleration), thus performance. Attention is paid to wings and diffusers in ground effect and wheel aerodynamics. For the wings and diffusers in ground effect, major physical features are identified and force regimes classified, including the phenomena of downforce enhancement, maximum downforce and downforce reduction. In particular the role played by force enhancement edge vortices is demonstrated. Apart from model tests, advances and problems in numerical modeling of ground effect aerodynamics are also reviewed and discussed
Evaluation of a color fused dual-band NVG
No full textWe have tested a prototype dual-band NVG system consisting of two NVGs fitted with filters that split the NVG sensitive range into a short (visual) and a long wavelength (NIR) band. The Color-the-night technique (see Hogervorst & Toet, SPIE D&S ‘08) was used to fuse the images of the two sensors. We designed a color scheme especially optimized for the detection of camouflaged targets. The added value of this system was evaluated in an experiment in which observers had to detect targets (green and blue tubes). Daytime images were taken with a normal camera, and NVG images were recorded at night. Performance was tested for i) the visual band only, ii) the NIR-band only, iii) normal NVG, iv) daytime imagery and v) color fused dual-band NVG. The results show that some targets were detected in the individual bands, but most targets were detected in the dual-band system, with performance comparable to that of the band optimally presenting that particular target. Our evaluation shows the added value of dual-band over single band NVG for the detection of targets, and suggests better situational awareness and perceived depth
Transforming Airport Hubs into Future-Proof Multimodal Transport Hubs
No full textDevelopments in sustainability and digitisation outline a future of mobility, with multimodal transport becoming the new normal. Travel modalities will no longer be the focal point of mobility, but passenger experiences and the services that provide these will. In a mobility landscape where the passenger experience is key, and multi-leg trips are the norm, Multimodal Transport Hubs are essential players as they can facilitate high-quality intermodal transfers. However, this advanced application of Multimodal Transport Hubs does not yet exist in practice.By employing a scoping review, this research aims to investigate the position of airport hubs as Multimodal Transport Hubs in the future of mobility, as airport hubs physically unite several transport infrastructures but only offer transfers with high-quality services within air traffic and not – to, from and between other modalities. To become future-proof, airport hubs should transform into truly Multimodal Transport Hubs that provide transfers with high-quality services from at least ultra-long to long and medium-range modalities.However, airport hubs have features such as a complex stakeholder landscape, long development times, reliance on transport operators and uncertainty about the added value of integrating new travel modalities that make modality innovation at airport hubs a systemic design challenge. This research identified a lack of theoretical knowledge regarding harnessing and integrating alternative and new modalities at airport hubs to transform them into fully integrated Multimodal Transport Hubs. In particular, how to assess and select new and alternative modalities, how to determine the appropriate level of engagement in different stages, and how to integrate new modalities at airport hubs should be investigated in future research.Marketing and Consumer ResearchApplied Ergonomics and Desig
Water desalination by capacitive electrodialysis: Experiments and modelling
No full textElectrodialysis-related technologies keep spreading in multiple fields, among which water desalination still plays a major role. A new technology that has not yet been thoroughly investigated is capacitive electrodialysis (CED), which couples the standard ED with capacitive electrodes. CED has a number of advantages such as removal of toxic products and system simplification. Little mention is made of this technology in the literature and, to the best of our knowledge, no modelling works have ever been presented. In this work, the CED process has been studied through experiments and modelling. A CED model is presented for the first time. With a simple calibration based on macroscopic membrane properties and the characterisation of electrode behaviour, the model is able to simulate the dynamics of simple as well as more complex layouts. An original experimental characterisation of electrodes is presented, showing how the collected data can be implemented into the model. After a successful validation with experimental data, dynamic simulations of a single pass CED unit have been performed with the aim of assessing the effect of different capacitive electrode properties on process performance. Results show how the impact of these properties is different depending on the number of cell pairs
Onboarding opportunities for digital transformation: A design that quickly generates and shapes initiatives, and creates insight into their potential value
No full textThe European Airline is a big company that focuses on efficiency, sustainability and customer experience. Its department DS strives to make the company smarter and more efficient. They create value by experimenting with technologies and methodologies, delivering products into people’s hands, and transforming the way of working. My project was conducted as part of the Portfolio Management team within DS. The Portfolio Management team enables decision-making on priorities and guides delivery of value. On assignment for DS, my intent for the project was to design a concept that quickly generates and shapes initiatives, and creates insight into their potential value. The project started with framing the problem. During the literature study, I concluded that three studies were leading for this assignment. Elements of successful portfolio management are described by Cooper et al. (2001) as strategically aligned, maximum portfolio value and portfolio balance. This can be achieved by having a portfolio mindset, being agile, and focusing whilst generating and shaping initiatives (Kester et al., 2011). The elements of portfolio orientation and structuring proved to be essential for the assignment as well (Meskendahl, 2010). I conducted external interviews, during which elements from literature gained meaning within the assignment. I discovered how the elements of Cooper et al. (2001), Kester et al. (2011) and Meskendahl (2010) could be applied within the context of the problem. I concluded that all insights obtained could be divided between strategically aligned, maximum portfolio value, portfolio balance and portfolio mindset. The underlying drivers of these elements led me to define design criteria. Different combinations of ideas resulted in four concepts, including the frame toolbox concept. The frame toolbox aims to transform the Frame Creation method (Dorst, 2015) into a tangible product, where initiative owners feel supported in the rapid generation and shaping of initiatives with maximum value as output. I subsequently developed the frame toolbox concept within DS’ context by testing its assumptions, hypotheses and challenges. This testing resulted in finding a connection between the frame toolbox and DS’ resources. This iterative design process led to my final design of Blink. Blink is a digital toolbox that transforms all types of innovations into valuable focus points for product teams. It quickly exposes problems, themes, solutions, and opportunities to their core and maximizes their potential value. By implementing a simple step-by-step plan, new opportunities are shaped that align with DS’ strategy. Blink helps participants to reframe their mindset by discovering the drivers of initiatives to define where the “real” value lies. This value is assessed by the value check tool. Focus points are evaluated on desirability and viability; this clearly shows its potential value. A portfolio mindset among employees is ensured through Blink’s structure and transparency. Blink can be performed in small and large groups, both online and offline. It enables participants to act flexibly due to the short turnaround time. It prioritizes speed, as it focuses on rapid screening of the initiative’s potential value. This thesis describes the process I followed in developing Blink and concludes with an implementation plan, a final reflection, Blink’s limitations, and recommendations for future designs.Strategic Product Desig
De impedantie-transparante versterker met logarithmische vertragingslijnen.
No full textBeschreven is de bouw van en de metingen aan de impedantie-transparante versterker met logarithmische vertragingslijnen als echo-onderdrukker. Gebleken is dat de vervorming van spraak te groot is om de echo-onderdrukker continu in een telefooncircuit te plaatsen. Een mogelijke voortzetting van dit onderzoek is de spraakgestuurde echo-onderdrukker.Electrical Engineering, Mathematics and Computer ScienceTransmissie van Informati
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