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Item type:Publication, Access status: without files , Tungsten band edge absorber/emitter based on a monolayer of ceramic microspheres(Soc., 2015-08-27); ; ; ; We report on a band edge absorber/emitter design for high temperature applications based on an unstructured tungsten substrate and a monolayer of ceramic microspheres. The absorber was fabricated as a monolayer of ZrO2 microparticles on a tungsten layer with a HfO2 nanocoating. The band edge of the absorption is based on critically coupled microsphere resonances. It can be tuned from visible to near-infrared range by varying the diameter of the microparticles. The absorption properties were found to be stable up to 1000°C.Publicationtype: Journal Article107 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Athermal and wavelength-trimmable photonic filters based on TiO2-cladded amorphous-SOILarge-scale integrated silicon photonic circuits suffer from two inevitable issues that boost the overall power consumption. First, fabrication imperfections even on sub-nm scale result in spectral device non-uniformity that require fine-tuning during device operation. Second, the photonic devices need to be actively corrected to compensate thermal drifts. As a result significant amount of power is wasted if no athermal and wavelength-trimmable solutions are utilized. Consequently, in order to minimize the total power requirement of photonic circuits in a passive way, trimming methods are required to correct the device inhomogeneities from manufacturing and athermal solutions are essential to oppose temperature fluctuations of the passive/active components during run-time. We present an approach to fabricate CMOS backend-compatible and athermal passive photonic filters that can be corrected for fabrication inhomogeneities by UV-trimming based on low-loss amorphous-SOI waveguides with TiO cladding. The trimming of highly confined 10 μm ring resonators is proven over a free spectral range retaining athermal operation. The athermal functionality of 2nd-order 5 μm add/drop microrings is demonstrated over 40.C covering a broad wavelength interval of 60 nm. 2Publicationtype: Journal Article34 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , An Analytical approach to evaluating nonmonotonic functions of fuzzy numbersThis paper presents a novel analytical approach to evaluating continuous, nonmonotonic functions of independent fuzzy numbers. The approach is based on a parametric α-cut representation of fuzzy numbers and allows for the inclusion of parameter uncertainties into mathematical models.Publicationtype: Journal Article692 342 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Characterization of the microstructure evolution in IF-Steel and AA6016 during plane-strain tension and Simple Shear(Multidisciplinary Digital Publishing Institute (MDPI), 2015-01-15); ; ; In the current work, the evolutions of grain and dislocation microstructures are investigated on the basis of plane strain tension and simple shear tests for an interstitial free steel (DC06) and a 6000 series aluminum alloy (AA6016-T4). Both materials are commonly-used materials in the automobile industry. The focus of this contribution is on the characterization and comparison of the microstructure formation in DC06 and AA6016-T4. Our observations shed light on the active mechanisms at the micro scale governing the macroscopic response. This knowledge is of great importance to understand the physical deformation mechanisms, allowing the control and design of new, tailor-made materials with the desired material behavior.Publicationtype: Journal ArticleScopus© Citations 2 485 437 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , TiO2 photocatalyst nanoparticle separation: flocculation in different matrices and use of powdered activated carbon as a precoat in low-cost fabric filtration(Hindawi Publishing Corporation, 2014-02-23); ; ; ; Separation of photocatalyst nanoparticles is a problem impeding widespread application of photocatalytic oxidation. As sedimentation of photocatalyst particles is facilitated by their flocculation, the influence of common constituents of biologically pretreated wastewaters (NaCl, NaHCO3, and their combination with humic acid sodium salt) on flocculation was tested by the pipetmethod. Results showed that the impact of these substances on TiO2 nanoparticle flocculation is rather complex and strongly affected by pH.When humic acid was present, TiO2 particles did not show efficient flocculation in the neutral and slightly basic pH range. As an alternative to photocatalyst separation by sedimentation, precoat vacuum filtration with powdered activated carbon (PAC) over low-cost spunbond polypropylene fabrics was tested in the presence of two PAC types in aqueous NaCl and NaHCO3 solutions as well as in biologically treated greywater and in secondary municipal effluent. PAC concentrations of ≥ 2g/L were required in order to achieve a retention of nearly 95% of the TiO2 nanoparticles on the fabric filter when TiO2 concentration was 1 g/L. Composition of the aqueous matrix and PAC type had a slight impact on precoat filtration. PAC precoat filtration represents a potential pretreatment for photocatalyst removal by micro- or ultrafiltration.Publicationtype: Journal ArticleScopus© Citations 13 474 556 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , An Extended analytical approach to evaluating monotonic functions of fuzzy numbersThis paper presents an extended analytical approach to evaluating continuous, monotonic functions of independent fuzzy numbers. The approach is based on a parametric α-cut representation of fuzzy numbers and allows for the inclusion of parameter uncertainties into mathematical models.Publicationtype: Journal ArticleScopus© Citations 3 568 348 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , A Tale of three cities : urban culture and social change in the Palestinian West BankBased on survey data of adolescents and parents from three major Palestinian cities, this article is a contribution to an ongoing debate on urban Arab culture and social change in the Middle East. Starting with a critical review of scholarly articles on the three West Bank cities of Hebron, Nablus, and Ramallah, we draw on evolutionary concepts of change from below, assuming varieties of urban modernization instead of global convergence of city cultures. In adopting a comparative approach, we argue that social transformation does not follow an overall pattern of global urbanization, but is locally configured by contradictions inherent to historically grown concepts of gender relations, patriarchal control, openness for difference, democratic liberties, secularism and Islamism. Our findings should help to understand how social and cultural change unfolds along varying paths of transition between tradition and modernity and is driven by intergenerational encounters and interurban exchange.Publicationtype: Journal Article1225 485 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Closed contour specular reflection segmentation in laparoscopic imagesSegmentation of specular reflections is an essential step in endoscopic image analysis; it affects all further processing steps including segmentation, classification, and registration tasks. The dichromatic reflectance model, which is often used for specular reflection modeling, is made for dielectric materials and not for human tissue. Hence, most recent segmentation approaches rely on thresholding techniques. In this work, we first demonstrate the limited accuracy that can be achieved by thresholding techniques and propose a hybrid method which is based on closed contours and thresholding. The method has been evaluated on 269 specular reflections in 49 images which were taken from 27 real laparoscopic interventions. Our method improves the average sensitivityby 16% compared to the state-of-the-art thresholding methods.Publicationtype: Journal ArticleScopus© Citations 17 628 380