2,363 research outputs found
R.C. Farrell Store
No full textPhotograph - People standing in front of R.C. Farrell, General Merchant store, Athabasca, Alberta. Left to right: Lance Smith, Louis Menard, Romeo Farrell, Athela LaRue Farrell, and Ray Vari
A Review of: Biobloc Therapy, by John R.C. Mew
No full textThis text, written and published by its British author, John R.C. Mew, details an integrated orthodontic and orofacial myofunctional treatment approach entitled Biobloc Therapy [...
Automatic detection of buried channel deposits using high resolution laser altimetry data (FLI-MAP)
No full textThe formation of the current Rhine-Meuse delta has mainly taken place during the Holocene (the last 12,000 years). This period is characterised by avulsions that lead to sudden shifts in the location of river channels. The channel deposits left behind by abandoned rivers are often distinct sandy layers in the shallow sub-surface, called buried channel deposits. Knowledge of the location of buried channel deposits is interesting from a historical point of view and is essential for planning, constructing and maintaining structures that intersect these channels. Traditionally, buried channel deposits are traced using labour intensive soil drillings and visual interpretation. However, some buried channel deposits can also be detected by using local elevation differences (1 - 2 m) caused by differential compaction. Automating the detection process and using Digital Elevation Models could result in faster processing and a higher detailed, more objective map. This leads to the following research question: is it possible to automatically derive a detailed map of buried channel deposits from high resolution laser altimetry data? The dataset used for this purpose is a rasterized elevation model measured by the FLI-MAP system with the same specifications as AHN-2. First, two filtering methods are applied to remove infrastructure and other objects using existing topographical data (GBKN) and terrain characteristics (variability and density). If these objects are not removed they cause errors in the final result. In the detection procedure four structural attributes are calculated using the elevation dataset: slope, curvature, relative elevation (TPI) and smoothed TPI. This is done to use as much of the available information in the detection procedure. With these attributes a multi-band image is formed. Classification is then performed using a Maximum Likelihood classifier were each point is assigned to a predefined class. A majority filter is applied on the result and empty areas are interpolated using a conditional dilation to get a full coverage of the area. Processing speed is increased by downsampling datapatches that are used for computational intensive algorithms. Additional automation of the detection process is performed by developing a method to resolve edge effects on tiled datasets. Validation is performed by comparing the detection result to two independent datasets. A palaeogeographic map is used to make a numerical and visual comparison. An analysis using shallow drilling measurements is performed to determine the depth of the detected sand layers. The results indicate that buried channel deposits (between 4,620 and 1,700 years old) can be mapped roughly in a fully automatic way. The probability that these channels are within a certain depth can be calculated. Validation shows that this new method is strongly hampered due to human intervention in the landscape. Further research is recommended to improve the filtering and detection method.Mathematical Geodesy and PositioningAerospace Engineerin
Experimental Research and Numerical Analysis on the Law of Deteriorated Performance for R.C. Frame Structure with Seismic Damages under Elevated Temperature (part II)
No full textThe cracks were pre-settled to the R.C. frame structure caused by earthquake which was defined as the damage index ω during the modeling process with analysis software-ANASYS. The temperature field contour curve were calculated for the column and beam, the law of deteriorated bearing capacity with time for the R.C. frame structure under elevated temperature were brought forward，which can adapt to R.C. frame structure with different damage index ω caused by earthquake.The relationship between ω and deteriorated bearing capacity for R.C. frame structure was also given, which was proved to be effective and correct according to comparison with the data recorded from the elevated temperature experiment designed by author.</jats:p
Glacier Surface Analysis. Airborne Laser Scanning for monitoring glaciers and crevasses
No full textAerospace Engineerin
Internal Friction in The Region of The Grain Boundary Peaks in Pure Zirconium and Dilute Zirconium Alloys
No full textTitle: Internal Friction in The Region of The Grain Boundary Peaks in Pure Zirconium and Dilute Zirconium Alloys, Author: R.C. Robinson, Location: ThodeInternal friction, in the region of the
grain boundary peaks, has been examined in nominally
pure zirconium and dilute zirconium alloys. Experimental
observations were made using both torsion and
reed internal friction pendulums. The effect of various
heat treatments on the peaks were investigated. Strain
amplitude dependent damping in the region of the Low
Temperature Peak was observed. A qualitative model
is presented to explain the experimental observations.ThesisMaster of Engineering (ME
De Fast-Fourier Transform: Het gebruik van de routine van R.C. Singleton
No full textDoel van dit rapport is de lezer inzicht te verschaffen in het gebruik van de FFT-routine van R.C. Singleton zoals die in het rekencentrum van de T.H. - Delft in gebruik is. Voor een beschrijving van de werking van deze routine wordt verwezen naar het in de literatuurlijst vermelde artikel van Singleton (Lit. 1). Met nadruk wordt erop gewezen dat er meerdere FFT-routines in omloop zijn die alle anders werken en daarom in gebruik kunnen verschillen. Het onderhavige rapport beschrijft uitsluitend het gebruik van de routine van Singleton. Als laatste punt in deze inleiding wordt speciaal het boek van Brigham genoemd (Lit. 2) waarin zeer veel informatie te vinden is over het gebruik van de FFT-methodeHydraulic EngineeringCivil Engineering and Geoscience
Assessing the performance of the sonAIR aircraft noise model in predicting noise levels at Schiphol Airport
No full textAircraft noise is a significant problem for communities surrounding airports. Accurate prediction models are needed to estimate noise levels from aircraft operations. In this research, the accuracy of the sonAIR aircraft noise model is evaluated in predicting noise levels around Schiphol airport by comparison to measurement data from NOMOS and the current best-practice modelling approach Doc29. Results show a significant but consistent underestimation of noise levels by sonAIR, mainly due to a generalisation of emission models. The standard deviation of differences between model results and measurements is lower for sonAIR than for Doc29 by up to 1 dB. Differences between measurement and model results were found in the relation between N1 and noise levels, maximum noise levels and frequency spectra. These results demonstrate that sonAIR provides more reliable predictions of noise levels on the single flight event level than Doc29. Additionally, this study shows agreement with results from a previous validation study in Zürich, thereby confirming the applicability of sonAIR to another airport. This research contributes to better aircraft noise predictions, which will have implications ultimately leading to a better quality of life for communities affected by aircraft noise.Aerospace Engineerin
The Challenge of Reversing Theories to Hybridize Structures with Fiber Metal Laminate Design Concepts
No full textTo further optimize aeronautical structures, an increased level of material hybridization is required. Optimization efforts aim to identify optimal design solutions that satisfy prescribed requirements. However, this demands reversal of currently available knowledge on hybrid structural technologies, which are often formulated as theories predicting performance based on known load cases and selected material configurations. After briefly reviewing the available fundamental theories for strength, fatigue, and damage tolerance of hybrid structures, this paper discusses the challenges in reversing these theories. Solutions are proposed in which theories can be approximated to significantly reduce the computational time while maintaining the required level of accuracy.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.Structural Integrity & Composite
Validation of the Aircraft Noise and Performance Database Source Spectra
No full textAccurate modelling of aircraft noise in different weather conditions is crucial for the reliability of noise predictions and their application worldwide. In best-practice aircraft noise models, such as Doc.29, the change in expected sound level on the ground due to changing atmosphere is modelled with a simplified propagation calculation. The Aircraft Noise and Performance (ANP) database contains several standardised source spectra, known as spectral classes, which are used for these calculations to account for the frequency dependence of the atmospheric effects. The spectral classes consist of Pressure Band Levels (PBL) of 24 1/3rd octave bands. This research focuses on the agreement of these spectral classes with measurements, taken around Amsterdam Schiphol Airport, and quantifies the effect of differences in these spectra for the Doc.29 weather correction. The measurements, taken by an acoustic array close to the runway and by continuous single microphone noise measurement stations (NOMOS) at long range, are propagated to the standard distance of 1000 ft (for which the ANP spectral classes are given) taking into account the geometrical spreading and the actual atmospheric absorption. For the B737-800 and A330, differences in shape are found between the two measured spectra and the spectral class. This is partly due to the low signal-to-noise ratio for the high frequencies in case of large distances between the aircraft and the measurement system. The effect of the application of the measured spectra on the Doc.29 weather correction is found to be smaller than 0.5 dBA for the NOMOS positions, indicating the suitability of the current ANP spectral classes for the weather correction
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