124 research outputs found
Hoogwater 2021: Feiten en Duiding
No full textIn juli 2021 zijn grote delen van Limburg getroffen door hevige regenval en overstromingen. Ook delen van België en Duitsland overstroomden met zeer veel schade en verlies aan mensenlevens tot gevolg. Dit betrof een extreme en ongeëvenaarde gebeurtenis met enorme impact. Daarom is naar aanleiding van de overstromingen deze verkenning uitgevoerd om een eerste stap te maken om beschikbare informatie over deze gebeurtenis te verzamelen en analyseren. Het onderzoek is uitgevoerd door een breed consortium (TU Delft, Deltares, HKV Lijn in Water, VU Amsterdam, Universiteit Utrecht, KNMI, WUR, Erasmus MC en Universiteit Twente) in opdracht van het Expertise Netwerk Waterveiligheid (ENW). Een overstroming heeft effect op de hele maatschappij. Daarom zijn niet alleen hydrologische en civieltechnische onderwerpen beschouwd, maar ook de maatschappelijke gevolgen van overstromingen, de crisisrespons en de gezondheidseffecten.Contributors (in alphabetical order): Nathalie Asselman (Deltares), Hermjan Barneveld (HKV / Wageningen UR), Jules Beersma (KNMI), Eline Boelee (Deltares), Wouter Botzen (VU Amsterdam), Eefke Copper (TU Delft), Dim Coumou (KNMI), Karin de Bruijn (Deltares), Anniek de Jong (Deltares), Jurjen de Jong (Deltares), Hans de Moel (VU Amsterdam), Ferdinand Diermanse (Deltares), Astrid Fischer (Evides) , Gert-Jan Geerling (Deltares), Marie-Louise Geurts (WML), Rob Groenland (KNMI), Mark Hegnauer (Deltares), Bas Jonkman (TU Delft), Nicole Jungermann (KNMI), Frans Klijn (Deltares), Andre Koelewijn (Deltares), Matthijs Kok (HKV / TU Delft), Elco Koks (VU Amsterdam), Bas Kolen (HKV / TU Delft), Marion Koopmans (Erasmus MC), Laurens Leunge (Deltares), Hans Middelkoop (Utrecht University), Roelof Moll (TU Delft), Jaap Mos (Dunea), Sjoukje Philip (KNMI), Gerbert Pleijter (HKV), Joost Pol (HKV / TU Delft), Stephan Rikkert (TU Delft), Guus Rongen (TU Delft), Rinus Scheele (KNMI), Julius Schlumberger (TU Delft), Peter Siegmund (KNMI), Kymo Slager (Deltares), Frederiek Sperna Weiland (Deltares), Bart Strijker (HKV / TU Delft), Henk v.d. Brink (KNMI), Janko van Beek (Erasmus MC), Marion van den Bulk (TU Delft), Bart van den Hurk (Deltares), Tim van Emmerik (Wageningen UR), Kees van Ginkel (VU Amsterdam / Deltares), Mick van Haren (TU Delft), Margreet van Marle (Deltares), Malou van Schaijk (TU Delft), Dennis Wagenaar (Nanyang TU), Davide Wüthrich (TU Delft)Hydraulic Structures and Flood RiskSafety and Security ScienceCoastal Engineerin
Evaluation of Candidate Genes in Case-Control Studies: A Statistical Method to Account for Related Subjects
No full textTraditional case-control studies provide a powerful and efficient method for evaluation of association between candidate genes and disease. The sampling of cases from multiplex pedigrees, rather than from a catchment area, can increase the likelihood that genetic cases are selected. However, use of all the related cases without accounting for their biological relationship can increase the type I error rate of the statistical test. To overcome this problem, we present an analysis method that is used to compare genotype frequencies between cases and controls, according to a trend in proportions as the dosage of the risk allele increases. This method uses the appropriate variance to account for the correlated family data, thus maintaining the correct type I error rate. The magnitude of the association is estimated by the odds ratio, with the variance of the odds ratio also accounting for the correlated data. Our method makes efficient use of data collected from multiplex families and should prove useful for the analysis of candidate genes among families sampled for linkage studies. An application of our method, to family data from a prostate cancer study, is presented to illustrate the method's utility
Bereiding van acrylzuur
No full textDocument(en) uit de collectie Chemische Procestechnologie.DelftChemTechApplied Science
Santos, Rotterdam: From vacant to active monument, a creative office for Katendrecht
No full textSantos is a warehouse from the beginning of the 20th century, that has been vacant for most of its existence. Located on Katendrecht, it is placed right in the middle of a future high-density plan for 'de Pols', which focuses on attracting urban creators. By turning Santos into a creative office, the thesis builds upon these plans from the municipality, and attempts to once again turn Santos into a building that houses activity, instead of vacancy. The main design challenge concerns maintaining the industrial spirit of place, and the important clue that Santos provides towards Katendrecht's harbour history, all while creating the pleasant working conditions that an office requires (daylight being the most prominent one)
Security Evaluation of GoQuorum-based Smart Contracts: A Case Study of Malfunctioning Access Control and Double-Spending
No full textGoQuorum is an enterprise blockchain platform that supports smart contracts and allows for private transactions. Smart contracts enable automated payment while eliminating the need for third-party involvement. Previous attacks on smart contracts have already shown that existing vulnerabilities can lead to great financial losses. Yet, a study focusing specifically and exclusively on the security of GoQuorum-based smart contracts does not yet exist. This work evaluates two vulnerabilities: faulty use of tx.origin in authentication and private state divergence. Three attacks are demonstrated, leading to draining a contract's ether balance and double-spending. MythX is recommended to detect vulnerable code, while replacing tx.origin with msg.sender eliminates the vulnerability. It is concluded that Zero-Knowledge Proofs are a promising solution to validate transactions while maintaining privacy, although applying them to GoQuorum requires more research and development.CSE3000 Research ProjectComputer Science and Engineerin
Process Status Evaluating Tool: How can the pump process be evaluated pumping water?
No full textDamen Dredging Equipment (DDE) has a quest to make their cutter suction dredger (CSD) and their DOP pump operable by everyone for every slurry type at the correct working point every time. To complete this quest, first a process status evaluating tool has to be developed which replaces the visual wear inspection. This thesis is the first step in developing this tool, its research question hence is "How can the pump process status be evaluated pumping water?" To answer this question, first a literature study about a centrifugal pumpis done (chapter 1) to understand the working principle of a centrifugal dredge pump. Next, the wear locations in a centrifugal dredge pump are going to be examined (chapter 3) after a small wear definition introduction (chapter 2). From the wear locations found, the ones that are expected to have the most influence on the pump performance (head H and efficiency ´) are further researched in this thesis. These locations are: the axial gap and the inner impeller diameter. For the axial gap, data was already available due to previous research at DDE [1]. The data for the influence of the inner impeller diameter change is created by own experiments on the sediment transport circuit at DDE, these experiments are explained in chapter 5. Also another conditionmonitoring option (not only the influence of the pump parameters) is researched after different possibilities were investigated (chapter 4). This method is the vibration analysis of the pump and is used to see whether or not the influence of wear on the pump can bemonitored. This wear is created by pumping a slurry (sand-water) mixture through the sediment transport circuit while using casted steel for the impeller and wear plate (it would take a lot of time to create wear on the original nihard impeller and wear plate). The data for the axial gap, inner impeller diameter and vibrational analysis is explained in chapter 6. The research question can be answered in two parts: the influence on the pump parameters and the vibration analysis of the pump. The data analysis of the influence of the axial gap on the pump parameters (section 6.1) shows that it is possible to indicate whether the axial gap is small or large (2mm vs 11mm) by using a trialand- error method proposed in this study. The data analysis of the inner impeller diameter (section 6.2) shows two methods to calculate the inner diameter increase from the data obtained during the own experiments. Both methods are based on the change of the velocity triangles resulting in an extended version of the pump affinity law for head. The NPSH could not be measured decent, so no model is obtained for this. The last part to answer the research question is the vibrational analysis (in radial, axial and tangential direction). The BEP point can be found using the vibrational analysis (lower vibration level). Also cavitation in the pump is detected by the vibrational analysis (high scattering of vibrational data points). A last thing that can be seen is when the pump operates left from the BEP, the axial vibration level increases a lot. All the findings in chapter 6 should be tested for not only the DOP250, but for a various range of pumps and settings. This to conclude if the findings are applicable for every pump, or only for the DOP250 in setting used in the sediment transport circuit.Mechanical, Maritime and Materials EngineeringOffshore & dredging engineerin
Relatie korreldiameter en K-waarde voor sterk gegradeerde mengsels
No full textDe doorlatendheid van zand kunnen bepalen met één gegeven, de bepalende korreldiameter, is wegens het gemak in gebruik lange tijd een streven geweest, en is het nog steeds. De relatie tussen korreldiameter (d) en doorlatendheid (K-waarde) is door velen aangetoond, maar twijfel is er of deze relatie ook aanwezig is voor sterk gegradeerde zandmengsels. Uit een literatuurstudie volgt de kwadratische invloed van de korreldiameter op de K-waarde. Ook valt de dominantie van de formule van Kozeny-Carman over andere, vooral empirisch vastgestelde formules, op. De formule van Kozeny-Carman bevat een parameter S, het specifiek oppervlak. Deze parameter is gedefinieerd als de verhouding tussen het oppervlak en het volume van het zandmonster, gelijk aan 1/d. Volgens Kozeny-Carman is de invloed van deze parameter S op de K-waarde omgekeerd kwadratisch, wat neerkomt op een kwadratisch invloed van de korreldiameter. Door het specifiek oppervlak van het gehele monster te bepalen, wordt de invloed van elke korrel in het monster in rekening gebracht. Verschillende doorlatendheidsproeven zijn uitgevoerd met sterk gegradeerde mengsels, en de resultaten vergeleken met de voorspelling van Kozeny-Carman. Er kan geconcludeerd worden dat voor sterk gegradeerde mengsels de relatie tussen korreldiameter en K-waarde aanwezig is, en kwadratisch van aard. De beste manier om de invloed van verschillende korreldiameters in een monster weer te geven is door gebruik te maken van fracties met ieder een eigen gewichtspercentage en korreldiameter (zie rapport voor exacte formule).Hydraulic EngineeringHydraulic EngineeringCivil Engineering and Geoscience
Chimes: February 25, 2000
No full textTuition nears $19K by Nathan VanderKlippe
McCain wins Michigan, ensures long race by Melissa Slager
Racism summit faces past, forges future by Hillary Whitcomb
Crump gets reappointment despite controversial comments by Natasja VanderBerg
Students work as interns for McCain 2000, French embassy by Carolyn Davids
Professors form care group by Natasja VanderBerg
Project Neigborhood expands to second house by Barbara Pezet
Author Anne Lamott brings Christian voice to bestseller lists by Philip Christman
Men\u27s b-ball ties MIAA record by Leslie Pratt
Students Senate looks to eliminate appeals with budgeting changes by Nathan VanderKlippehttps://digitalcommons.calvin.edu/chimes/1435/thumbnail.jp
Unconventional surface state pairs in a high-symmetry lattice with anti-ferromagnetic band-folding
No full textMany complex magnetic structures in a high-symmetry lattice can arise from a superposition of well-defined magnetic wave vectors. These “multi-q” structures have garnered much attention because of interesting real-space spin textures such as skyrmions. However, the role multi-q structures play in the topology of electronic bands in momentum space has remained rather elusive. Here we show that the type-I anti-ferromagnetic 1q, 2q and 3q structures in an face-centered cubic sublattice with band inversion, such as NdBi, can induce unconventional surface state pairs inside the band-folding hybridization bulk gap. Our density functional theory calculations match well with the recent experimental observation of unconventional surface states with hole Fermi arc-like features and electron pockets below the Neel temperature. We further show that these multi-q structures have Dirac and Weyl nodes. Our work reveals the special role that band-folding from anti-ferromagnetism and multi-q structures can play in developing new types of surface states.This article is published as Wang, Lin-Lin, Junyeong Ahn, Robert-Jan Slager, Yevhen Kushnirenko, Benjamin G. Ueland, Aashish Sapkota, Benjamin Schrunk et al. "Unconventional surface state pairs in a high-symmetry lattice with anti-ferromagnetic band-folding." Communications Physics 6, no. 1 (2023): 78.
DOI: 10.1038/s42005-023-01180-6.
Copyright 2023 The Author(s).
Attribution 4.0 International (CC BY 4.0).
Posted with permission.
DOE Contract Number(s): AC02-07CH11358; 842901
Chimes: November 19, 1999
No full textRepublican candidates come to Calvin by Nathan VanderKlippe
CVN hosts award-winning author by Melissa Kruse
E-mail stations: PCs boot out Unix by Amy McGary
Wolterstorff speaks on justice in education by Nathan VanderKlippe
Festival of Faith and Writing features world-class lineup again by Beth Heinen
The cycle of recycling on campus by Tim Thompson
City lets off-campus students recycle with ease by Melissa Slager
Environmental issues elicit mixed responses by Melissa Kruse
Mens club volleyball wins home opener convincingly by Nate Fales
Forum gets new 6:30 a.m. spot on Michigan PAXTV by Nathan VanderKlippehttps://digitalcommons.calvin.edu/chimes/1428/thumbnail.jp
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