349 research outputs found
Double Bind: On Material Ethics
No full textGreen 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 Architectural Theor
The Delft intense slow positron beam 2D-ACAR facility for analysis of nanocavities and quantum dots
No full textPositron annihilation spectroscopy is a powerful method to study materials containing very small concentrations of atomic defects and embedded quantum dots. Depending on the method of producing positrons, there are bulk spectroscopies using fast positrons and depth profiling spectroscopies using slow positrons. Both types of spectroscopies are available at the Positron Centre Delft of the Interfaculty Reactor Institute and are applied in material science. This thesis describes the construction of and the first results obtained with a unique two-dimensional angular correlation of annihilation radiation (2D-ACAR) setup coupled to the continuous high intensity slow positron beam (POSH). This new setup allows for the first time high-resolution momentum distribution measurements of thin films, multilayers, interfaces and metallic quantum dots. Important new information con- cerning the geometric and electronic structure of these systems can be obtained with this setup. At this moment the facility is the only one of this kind in the world.Interfaculty Reactor Institut
Multiscale and probabilistic modelling of micro electromechanical systems
No full textMicro electromechanical systems (MEMS) are nowadays used in many applications, such as airbag accelerometers and inkjet printer heads. With the number of applications growing, the need for advanced numerical tools to aid in the design of MEMS increases. The development of such tools is far from trivial, since numerical modelling of MEMS poses various challenges, such as the simulation of multiphysical effects, multiscale effects and effects of microstructural randomness. In this dissertation, computational techniques have been developed to asses the reliability of MEMS. More specifically, a cohesive zone formulation has been used to mimic crack growth in piezoelectric continua. A multiphysical finite element model has been developed to correctly simulate the electromechanical coupling in such materials. A computational homogenisation method has been proposed to efficiently incorporate microstructural effects in a macroscale analysis. Stochastic finite element methods have been employed to include the effects of microstructural imperfections on the behaviour of MEMS.Aerospace Materials & ManufacturingAerospace Engineerin
Effect of N<sub>2</sub> and CO<sub>2</sub> bubbles on gas volume fraction and flow pattern in a quasi-2D bubble column by shadow imaging
No full textThis study reports the effect of N2 and CO2 bubbles on dilute to dense gas-liquid two-phase bubbly flow. A shadowgraph imaging technique captured bubble images at a high spatiotemporal resolution. The recordings of bubble images allow us to compute gas fraction distribution. It requires challenging segmentation and gas-liquid interface detection approaches in image processing. Hence a novel gas contour characterization technique has been introduced in this study that analyses light intensity per pixel for quantifying the effect of local gas volume fraction. The dominant gas structure and repetitive gas pattern have also been determined here using Fourier transform-based power spectral density and 2D cross-correlation functions, respectively. Gas-liquid flow regimes of dissolved CO2 bubbles are found quite different than that of N2 bubbles. The plausible reasons are that gas fraction distribution at the sparger region may inhibit bubble coalescence and the positive surface charge of CO2 bubbles acts as a barrier to the interface deformation.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.ChemE/Transport PhenomenaChemE/O&O groe
Second-round interlaboratory comparison of hepatic ethoxyresorufin-O-deethylase activity in white sucker (Catostomus commersoni) exposed to bleached-kraft pulp mill effluent
No full textLivers were collected from six male and six female white sucker (Catostomus commersoni) at both a bleached-kraft pulp mill effluent (BKME)-exposed site and a reference site during the 1992 spring spawning migration. A semistandardized methodology for 7-ethoxyresorufin-O-deethylase (EROD) analysis was proposed that featured similar physical and chemical conditions yet allowed for different instrumentation and techniques. Postmitochondrial supernatants (PMSs) were analyzed for EROD activity by 14 laboratories, and repeat EROD analyses were performed within one laboratory to estimate within-laboratory variability. All laboratories found significantly higher levels of EROD activity (approximately threefold) in males from the BKME-exposed site; only 5 of 14 laboratories found significantly higher levels in exposed females. Data from three labs were dropped from the analysis because of outlying values. The mean coefficient of variation (C.V.) for the remaining 11 laboratories was 34.7%, which was not significantly different from the C.V. determined for six analyses by one technician (28.4%). The mean C.V. for five analysts within one laboratory was significantly lower (16.4%) than either of the former values. There was no difference in absolute values or the variability of microplate and conventional EROD assay data. Analysis of Bradford and Lowry protein data showed that both assays have low variability (C.V.s = 16.8 and 17.4%, respectively); these two techniques produced very similar estimates of protein content. Immunochemical analysis demonstrated a significant correlation existed among microsomal P4501A concentration and EROD activity. Sources of commercially available resorufin standard were tested, and the mean molar extinction coefficient was 54.0 +- 1.1 cm-1 mM-1.PT: J; UT: BIOSIS:PREV199598459590Source type: Electronic(1
Agno casto flore albo, Agno casto flore ceruleo
No full text1-2. Nome scientifico: Vitex agnus-castus L. c.v.
(Verbenaceae)
Nome attuale: Agnocasto, Lagano, Vitic
Design, Development and Implementation of a Low Cost Weather Station for high mountains
No full textACKNOWLEDGMENT We thank the INAIGEM for accomplish the Project “Evaluación y estimación de la distribución espacio temporal de permafrost a nivel nacional como potencial de reserva hídrica - PERMAFROST” and CONCYTEC-FONDECYT for funding (call number E041-01, contract number N°23-2018-FONDECYT-BM-IADT-MU).This research is based on the need to have a measurement tool to carry out different studies that require meteorological information in high mountain areas, therefore, a low-cost weather station based on open source is designed and implemented. The design process considered the inclusion of the directives of the World Meteorological Organization and the place of installation. Then we continued with the assembly and installations in conjunction with a Campbell Scientific station (3800 m) and a HOBO station (5000 m), in order to compare their records. The Arduino Mega 2560 controller used as a datalogger responded adequately, the data captured when compared are very similar to those of the stations. The average difference between the low-cost station and the other two is in temperature 0.193 °C, humidity 1.3% RH, atmospheric pressure 0.14 mbar, solar radiation 5.8%, soil temperature 0.127 °C, wind speed 0.485 m/s and wind direction 1.33°. The cost benefit is 4 to 18 times compared to purchasing a commercial station and certified instrumentation. © 2021 IEEE.Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
Shanti 20
No full textOne of twenty in the series, found near the counter as we were settling up a large order of books. The finish of this version of FS is particularly strong, both in text and picture. The fox was very angry. But he could not show it since he had done the same to her. Moral: As you sow, so shall you reap. The last image of the fox expresses his anger wonderfully!Edited by C.V. Indir
Shanti 14
No full textOne of twenty in the series, found near the counter as we were settling up a large order of books. This version of WS is told in the poorer form. The travelller here is, in a good touch, wearing a shawl. 'Whosoever would make the traveller remove his shawl, would be the winner,' insisted the sun.' Intelligence is strength. Slick computer-generated art on sixteen pages of a pamphlet.Edited by C.V. Indir
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