1,006 research outputs found
Manual Hydraulic Structures
No full textThis manual is the result of group work and origins in Dutch lecture notes that have been used since long time. Amongst the employees of the Hydraulic Engineering Department that contributed to this work are dr.ir. S. van Baars, ir.K.G.Bezuijen, ir.G.P.Bourguignon, prof.ir.A.Glerum, dr.ir.P.A.Kolkman, ir. H.K.T. Kuijper, ir. H.G. Voortman and prof.drs.ir. J.K. Vrijling. The latest years, this manual has been clarified, revised and expanded by ir. W.F. Molenaar and ing. M.Z. Voorendt. We have received much feedback from students and got good input from our student-assistants, which is highly appreciated and has been taken taken into account for this new edition. In the 2016 edition, some minor corrections were made throughout the Manual, most noticeably the equation for the spring stiffness of a combined system in Section 29.2. Section 11.1 has been updated with more generic weir discharge equations. Furthermore, serviceability requirements have been added to the chapter on wave-overtopping (Chapter 17) and the Blum theory for laterally loaded piles has been better explained in Chapter 44. The largest change is the addition of Chapter 49, about the determination of the height of flood defences
The Creation of Synthetic Digital Ground-Truth Images of Historic Cosmic Ray Data Recordings
No full textThe aim of this paper is to develop a set of algorithms for the automated construction of synthetic digital ground truth images from historic cosmic ray recordings. These images can subsequently be used to test data extraction algorithms. This takes place in a larger research context of an effort to retrieve and digitize the data contained within more than 20 years (1934–1956) of historic cosmic ray data from around the world. The creation of synthetic ground truth images can logically be broken down into component tasks, which can be approached individually. These tasks include: binarization, segmentation, as well as generation of optical artefacts and distortions. The approach and details of the algorithm are describe
An Investigation of Consumer Loyalty to Stores
No full textTitle: An Investigation of Consumer Loyalty to Stores, Author: Gordon W.F. Parsons, Location: ThodeIn recent years there has been growing commercial and academic interest into the question of consumer purchasing behaviour at stores, and a great deal of research has been done on this topic using aggregate consumer data. The main study objective of this investigation was to ascertain the nature of consumer store loyalty across different product
fields, consumer characteristics, and shopping trip characteristics, based on an analysis of consumer purchasing sequences carried out by the 'run test'. The analysis of data extracted from the Cardiff Consumer Panel, a data set which includes continuous records of the grocery shopping
behaviour using the this approach revealed a number observations on the nature of consumer purchasing behaviour, including a link between car ownership and store loyalty.ThesisBachelor of Arts (BA
De invloed van de atmosfeer en de warmtebehandeling bij het electrisch lasschen
No full textMechanical, Maritime and Materials Engineerin
Global buckling mechanism of sheet piles: The influence of soil to the global buckling behaviour of sheet piles
No full textFor the design of a steel sheet pile, verification checks should be done on multiple failure mechanisms. One of the failure mechanisms which should be checked is the check on global buckling. This is a mechanism in which the deformation of the pile is enlarged due to the normal or vertical force. With the enlargement of the sheet pile, the soil must be displaced as well, which results in extra resistance against global buckling. However, the check to this mechanism stated by the Eurocode is based on the so called critical global buckling load, which is currently based on the stiffness of the sheet pile. The resistance delivered by the soil is fully neglected in the check on global buckling, which gives that it is thought that this check is too conservative. It is studied how the influence of the soil can be taken into account to the global buckling mechanism. This is done by describing the background of the current check, followed by stating possible methods to determine the influence of the soil. By the use of calculation program’s D-sheet pilling and Plaxis 2D, some examples are calculated in which the proposed methods are compared with the current method. From those examples, it was found that the check on global buckling might be significant lower if the influence of the soil is taken into account.Civil Engineering | Hydraulic Engineering | Hydraulic Structures and Flood Ris
Extracting the Ground Level Enhancement Event of February 1956 from Legacy Cosmic Ray Recordings
No full textEarly continuous recordings of cosmic rays, as measured with Carnegie Type C Ionization Chambers, were made on rolls of photographic paper. This paper describes the extraction of the ionization data of a ground level enhancement (GLE) event from the ionization chamber recordings of three stations, viz.: Godhavn, Cheltenham, and Christchurch. The extracted ionization data was then converted to percentage increase above background cosmic ray levels and compared to existing neutron monitor data. The recordings share common attributes, such as a sharp rise to a peak which tapers off more slowly. This trend, seen in all three data sets, is consistent with the neutron monitor dat
Fluorinated building blocks for next-generation polymer electrolyte membrane fuel cells
No full textThe purpose of this thesis is to design, create and study basic building blocks for the construction of self-assembled nanostructured electrodes and membranes for PEMFC. The research described deals with the synthesis of polymerizable fluorosurfactant (1) and its non-polymerizable analogue (2) and the study of their self-assembly properties. Similarly, the (co)polymerization behavior of 1 and the polymer properties are described. The design of the polymerizable fluorosurfactant, 1 and the synthetic routes to obtain the desired functionalities and molecules are discussed in Chapter 1. The reaction pathways to create –SO3¯ as well as styryl groups are described. The syntheses of compounds 1 and 2 are described in Chapter 3. The key reactions viz. the copper mediated cross-coupling reactions to attach fluorocarbon molecules to aromatic moieties and the Wittig reactions to obtain styryl functionalities are described. The micellization properties of 1 and 2 are deliberated in Chapter 4. Unlike, several fluorinated sulfonic acid salt surfactants, both surfactants were soluble in water at room temperature. This is due to their hybrid character and the presence of bulky aromatic moieties in the surfactant tails. Both compounds 1 and 2 display comparable cmc values ~30 mM, and form spherical shaped micelles. The Gibbs energy of micellization of 1 and 2 are in the range of -24 to -26 kJ mol-1. The micelles were characterized by low aggregation numbers, in the range of 25 to 35. Entropy driven micelle formation and a U-shaped relation was observed between the Gibbs energy of micellization and experiment temperatures were observed. The LLC phase behavior of 2-water mixtures is described in Chapter 5 and two lyotropic phases in the range of 63 to 84 wt% 2 were identified and investigated. An unprecedented supramolecular columnar (Cs) phase made up by self-assembly of “Leek” shaped aggregates was observed in the concentration regime between 63 and 70 wt% 2, and a lamellar (L?) phase was observed from 70 to 84 wt% 2. The “Leeks” were shown to be formed by wrapping up of the 2-water bilayers. An interdigitated and/or tilted assembly of 2 molecules was suggested for both LLC phases based on SAXS data analysis. Homo and copolymers of compound 1 with model the perfluorinated comonomer, 3 or styrene were prepared by free radical method, and are discussed in Chapter 6. The strong incompatability of ionic groups and fluorocarbon moieties of poly-1 severely hampered the molecular weight determination by GPC. Homopolymer of 3 is insoluble in most of the polar as well as nonpolar solvents. 19F NMR experiments revealed that there are inhomogeneities within the copolymer samples synthesized from 1 and 3 because of the large compositional drifts with respect to the comonomer feed ratios occurred during the polymerization. Thermal stabilities of all polymers were slightly better compared to the thermal stability of polystyrene. Cryo-TEM P1-water solution revealed the formation of elongated worm-like micelles with ~5 nm diameter and length of up to 400 nm. These micelles were suggested to be formed by the lateral self- assembly of 2-3 extended polymer chains of P1.Chemical EngineeringApplied Science
Extraction and Visualization of Dimensions from a Geometric Model on the basis of its Medial Axis
No full textComputer Graphics and CAD/CAM GroupElectrical Engineering, Mathematics and Computer Scienc
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