Searched for: subject%3A%22LUMEN%22
(1 - 11 of 11)
document
Rocchetta, Roberto (author), Zhan, Zhouzhao (author), van Driel, W.D. (author), Di Bucchianico, Alessandro (author)
Lifetime analyses are crucial for ensuring the durability of new Light-emitting Diodes (LEDs) and uncertainty quantification (UQ) is necessary to quantify a lack of usable failure and degradation data. This work presents a new framework for predicting the lifetime of LEDs in terms of lumen maintenance, effectively quantifying the natural...
journal article 2024
document
Trotta, Luca (author)
High-frequency combustion instabilities represent the main technical risk faced by design engineers when developing new chemical rocket propulsion systems. Such instabilities are driven by the coupling between the flames’ heat release rate and the combustion chamber’s acoustic field. As such, they can only be assessed during detailed design...
master thesis 2023
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Yazdan Mehr, M. (author), Bahrami, A. (author), van Driel, W.D. (author), Fan, X.J. (author), Davis, J.L. (author), Zhang, Kouchi (author)
In this paper, degradation mechanisms of optical materials, used in the light emitting diode (LED)-based products, are reviewed. The LED lighting is one of the fastest technology shifts in human history. Lighting accounts for almost 20% of the global electrical energy use, inferring that replacement of traditional lighting sources with LEDs...
journal article 2020
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van Driel, W.D. (author), Middelburg, L.M. (author), el Mansouri, B. (author), B.J.C., JAcobs (author)
Traditional lighting is focused on the prevention of hardware failures. With the trend towards controlled and connected systems, other components will start playing an equal role in the reliability of it. Here reliability needs to be replaced by availability and other modeling approaches are to be considered. System prognostics and health...
book chapter 2020
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Yazdan Mehr, M. (author), Toroghinejad, M.R. (author), Karimzadeh, F. (author), van Driel, W.D. (author), Zhang, Kouchi (author)
Reduction of intensity of light output is one of the most common degradation modes in light-emitting diode (LED) systems. It starts from the failure of the various components in the system, including the chip, the driver, and optical components (i.e. phosphorous layer). The kinetics of degradation in real life applications is relatively slow...
journal article 2018
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Sun, Bo (author), Fan, Xuejun (author), van Driel, W.D. (author), Cui, Chengqiang (author), Zhang, Kouchi (author)
In this study, we present a general methodology that combines the reliability theory with physics of failure for reliability prediction of an LED driver. More specifically, an integrated LED lamp, which includes an LED light source with statistical distribution of luminous flux, and a driver with a few critical components, is considered. The...
journal article 2018
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van Driel, W.D. (author), Schuld, M. (author), Jacobs, B. (author), Commissaris, F. (author), van der Eyden, J. (author), Hamon, B. (author)
Commercial claims for LED-based products in terms of lumen maintenance are fully based on TM-21 extrapolations using LM-80 data. This paper indicates that there may be a risk in doing this as TM-21 only relies on the behavior of the average LED degradation, instead of taking into account the degradation of all individual LEDs. Therefore, we...
journal article 2016
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Yazdan Mehr, M. (author), van Driel, W.D. (author), Zhang, Kouchi (author)
In this paper, progresses of color maintenance, also known as color shift, in solid-state lighting (SSL) systems are thoroughly reviewed. First, color shift is introduced and a few examples are given from different real-life industrial conditions. Different degradation mechanisms in different parts of the system are also explained. Different...
review 2015
document
Zuijdweg, J.M.A. (author)
Since a few decades, the use of Minimally Invasive Surgical (MIS) instruments has increased very fast. Minimally Invasive Surgery usesmuch smaller incisions compared to the traditional open surgery. The procedure is less invasive than open surgery and there is minimal damage to biological tissues at the point of entrance of the instrument. This...
master thesis 2014
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Carvalho, D.D.B. (author), Klein, S. (author), Akkus, Z. (author), Ten Kate, G.L. (author), Schinkel, A.F.L. (author), Bosch, J.G. (author), Van der Lugt, A. (author), Niessen, W.J. (author)
Purpose The purpose of this paper is to present a methodology to estimate the carotid artery lumen centerlines in ultrasound (US) images obtained in a free-hand examination. Challenging aspects here are speckle noise in US images, artifacts, and the lack of contrast in the direction orthogonal to the US beam direction. Method An algorithm based...
journal article 2011
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Tang, H. (author), Van Walsum, T. (author), Van Onkelen, R.S. (author), Klein, S. (author), Hameeteman, R. (author), Schaap, M. (author), Van den Bouwhuijsen, Q. (author), Witteman, J.C.M. (author), Van der Lugt, A. (author), Van Vliet, L.J. (author), Niessen, W.J. (author)
We propose a minimum cost path approach to track the centerlines of the internal and external carotid arteries in multispectral MR data. User interaction is limited to the annotation of three seed points. The cost image is based on both a measure of vessel medialness and lumen intensity similarity in two MRA image sequences: Black Blood MRA and...
conference paper 2011
Searched for: subject%3A%22LUMEN%22
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