1,098 research outputs found
Quantifying Structural Response in a Through-fall Drought Experiment Using Terrestrial Laser Scanning
No full textTerrestrial ecosystems provide a very wide range of essential ecosystem services, but these services are under increased levels of stress due to climate change. Ecosystem structure and climate are closely-linked: changes in climate lead directly to physical changes in ecosystem structure and vice versa. To improve our understanding of this relation and ecosystem resilience, we require information of the fine-scale structural heterogeneity between individual trees. This will be key for effective forest management and to support climate mitigation actions appropriately. Drought experiments, which simulate drought conditions by excluding rainfall from a given zone, bring highly valuable information on the mechanisms involved in the response of ecosystems to drought (Bonal et al., 2016). Novel techniques using 3D laser scanning (LiDAR – Light Detection and Ranging) can provide us with a new way to estimate the structure of individual trees. Terrestrial laser scanning (TLS) can measure the canopy structure in 3D with high detail, and several algorithms have recently been developed to produce full 3D models of trees down to fine (cm) scale. Terryn et al. (2020) calculated 17 different structural tree metrics in the context of tree species identification. Within this study we explore the same structural metrics to determine if induced drought affects tropical tree structure on a time-span of 3 years using TLS. For this purpose we will extract 59 individual trees from TLS data from a through-fall drought experiment in Australia. Quantitative Structural Models (QSMs) will be built with TreeQSM to obtain the individual tree structures. Tree structure from the control trees will be compared with the tree structure of the drought induced trees using structural metrics obtained from the QSMs
Recyclable and Self-Healing Stretchable Strain Sensor Based on Liquid Metal and Diels-Alder Polymer for Smart Wearable Applications
No full textThe vulnerability of smart wearables necessitates stretchable sensors capable of recovering their functionality after sustaining damage. Recent research on liquid metal (LM)-based sensors demonstrates the potential of these highly stretchable, conductive, and reliable sensors. Unlike previous studies using silicone-based substrates, this article proposes a self-healing (SH), biocompatible strain sensor based on Galinstan embedded in a Diels-Alder (DA) polymer encapsulant. The novelty of this sensor lies in its ability to restore sensing and mechanical functionalities through numerous damage-healing cycles. This research outlines the fabrication and quasi-static and dynamic characterization of the strain sensor, enabling analysis of its strength, sensitivity, hysteresis, response time, drift, and healing performance. Healing is investigated by repeatedly rupturing the sensor in half, then healing it at 60 (degrees) C for 4 h before recharacterization. On a mechanical level, healing efficiencies of 80% are achieved based on recovered strain, while on a sensor level, the gauge factor (GF) is recovered with 105% efficiency. The degree of hysteresis (DH) for resistance-strain is less than 1%, and the sensing behavior is independent of strain rate. The sensor has a response time of 220 ms with an acceptable drift of 5% over 800 cycles. This article demonstrates the feasibility of recycling the sensor by outlining a method to separate the substrate from the LM and reprocess it. In addition, the sensitivity and biocompatibility of both pristine and healed sensors are validated through case studies, such as tracking finger and knee joint angle bending, highlighting their potential for smart wearable applications. Supplementary video material can be found at https://www.youtube.com/watch?v=SeLYJ6_qT_kRathul Nengminza Sangma, Kevin Langlois, Ehsan Mirabdollah, and Bram Vanderborght are with BruBotics, Vrije Universiteit Brussel and imec, 1050 Ixelles, Belgium (e-mail: [email protected]). Seppe Terryn is with BruBotics, Vrije Universiteit Brussel and imec, 1050 Ixelles, Belgium, and also with the Department of Materials and Chemistry, Sustainable Materials Engineering, Vrije Universiteit Brussel, 1050 Ixelles, Belgium.
Maximilian Krack, Lennert Purnal, Michael Daenen, and Wim Deferme are with the Institute for Materials Research, Hasselt University, 3590 Diepenbeek, Belgium. Fatemeh Sahraeeazartamar, Parth Vinayakrao Sewlikar,
Iris De Graeve, Joost Brancart, and Guy Van Assche are with the Department of Materials and Chemistry, Sustainable Materials Engineering, Vrije Universiteit Brussel, 1050 Ixelles, Belgium
Floating WIM Threshold Concept for Truck Weight Enforcement
No full textWeigh stations are the primary weight compliance checkpoints for commercial trucks. In the past several decades, states have used weigh-in-motion (WIM) technology to reduce delay and increase enforcement on overweight vehicles. This study offers a detailed analysis of weigh station systems and presents floating-threshold algorithms to improve the efficiency of WIM equipped weigh stations.
This research evaluates weigh station design and operational parameters using queueing theory and found that WIM technology not only enhances the effectiveness and efficiency of weigh station operations but also largely reduces travel delay for trucking companies. The effects of truck demand, truck weight distribution, static scale service time, WIM accuracy, and sorting threshold on weigh station operations have been analyzed. The author shows the importance of transponders in a WIM mainline weigh station operation. The author also proves that the increase of storage spaces within a weigh station may largely increase truck travel delay and does not significantly improve weigh station operations.
This research focuses on the development of floating-threshold algorithms. Since the number of trucks, particularly heavy trucks, has increased rapidly in recent decades, many weigh stations cannot meet the demand even when equipped with WIM systems. This problem is complicated by the fact that truck demands, truck weight distribution, and static scale service time vary by time of day and day of week. The author designed floating-threshold algorithms to automatically adapt to high truck demand and the varying of truck demand, truck weight distribution, and static scale service time, over time. When the queue at the weigh station is long, the threshold value is increased so as to avoid the closure of the weigh station while still catching the worst weight limit offenders. When the queue is short, the threshold value is lowered to increase the number of trucks inspected. Both the traditional fixed-threshold strategy and two floating-threshold strategies were modeled and tested using a microscopic simulation model. The results show that floating-threshold strategies are both more effective in weight enforcement and more efficient for heavy traffic flow and high-variance environments. The finding that different floating-threshold strategies have different effects indicates that it is necessary to make a further study on floating-threshold algorithms
M & L Jaargang 34/6
No full textDanny Keijers, Bert Tops en Wim De Baere De verdwenen kerk van Zelem. [The \u27lost \u27 church of Zelem.]Tot in de 17de eeuw bevond zich net voorbij het Limburgse dorpje Zelem, langsheen de huidige E314 autostrade, een mysterieus middeleeuws kerkje. Op vraag van de Vlaamse overheid startte studiebureau RAAP er een waarderend archeologisch onderzoek in combinatie met een zoektocht in verschillende archieven. Een schat aan nieuwe informatie was het resultaat. Op 6 november 2014 werd deze voormalige gewijde grond zelfs wettelijk beschermd. Danny Keijers, Bert Tops en Wim De Baere schetsen het ontstaan en het verval van deze oudste dorpsparochie van Zelem, nu een beschermde archeologische site.Caroline Terryn De Lievebermen in Damme. Getuigen van de grootschalige onteigening voor het Lievekanaal in de 13de eeuw. [The banks of the Lieve in Damme. Relics of a large-scale expropriation for the Lieve-canal during the 13th century.]In de 13de eeuw floreerde Gent als handelsstad. Het Lievekanaal, een grootschalig project dat gepaard ging met enorme infrastructuurwerken, vormde een 46,5 km lange tolvrije uitweg naar zee die eindigde in de overslaghaven Damme. Dat slechts de helft van het kanaal binnen de Gentse Oudburg lag en de andere helft buiten haar invloedssfeer, in het Brugse Vrije, doet vermoeden dat ook politieke motieven een rol speelden bij de aanleg. In het huidige landschap zijn de jaagpaden en een deel van de Lievebermen nog zichtbare en unieke getuigen van dit middeleeuwse kanaal. In deze bijdrage pleit Caroline Terryn dan ook voor verder onderzoek, waardering en bescherming.Dieter Nuytten Bouwgeschiedenis en restauratie van het Leuvense jezuïetencollege, later het veteranencollege. [Building history and restoration of the Leuven Jesuit College, the Collegium Veteranorum.]Elke bezoeker aan de Leuvense universiteitsstad wordt onmiddellijk geconfronteerd met de veelheid aan collegegebouwen. Minder bekend is het Collegium Veteranorum, oorspronkelijk gebouwd als het oudste jezuïetencollege in de voormalige Nederlanden. Dieter Nuytten beschrijft de woelige gebruiksgeschiedenis van de gebouwen, met talrijke afbraken en verbouwingen, tot aan de huidige restauratie en (alweer) herbestemming van de gebouwenvleugels van het Collegium Veteranorum, het enige overblijfsel van een eertijds veel groter complex. Vooral de constructieve elementen zoals voor- en achtergevels en enkele latere interieurelementen kregen tijdens deze restauratiecampagne hun noodzakelijke herwaardering.Edith Willekens Eclectische monumenten op papier vereeuwigd: de publicatie Parallèle des maisons de Bruxelles van Auguste Castermans. [Eclectic paper monuments perpetuated: the publication Parallèle des maisons de Bruxelles by Auguste Castermans.]De Luikse architect Auguste Castermans publiceerde in het midden van de 19de eeuw een platenalbum met voorbeelden van eclectische architectuur, bedoeld als inspiratiebron voor ontwerpers en opdrachtgevers, die de platen onderling konden vergelijken. Omdat deze publicatie nooit eerder uitvoerig onderzocht werd, nam Edith Willekens deze taak op zich en kon ze aantonen dat de Parrallèle des maisons de Bruxelles et des principales villes de la Belgique niet minder dan Castermans levenswerk was, zijn persoonlijk pleidooi voor het gebruik van deze eclectische bouwstijl in een periode van voortschrijdende commercialisering.Summar
The Impact of Tourism on Curacao's Economy: A Scenario Approach
No full textCuraçao is an autonomous countrywithin the Kingdom of the Netherlands. The governmentwants to support tourism development. However,various development strategies are possible. This articlepresents four scenarios of marketing and investmentstrategies that will affect the number of tourists fromThe Netherlands and North America (USA and Canada)in different ways. A multiplier model was used to calculatethe economic impacts of the four scenarios. Bydoing so, this article shows how the government’s decisionto support particular marketing and investmentstrategies may have certain outcomes for the number ofjobs in Curaçao’s tourism industry
Model Validation and New Water Control Strategies in Drinking Water Treatment Plant Wim Mensink
No full textStimela is an environment for standardized mathematical models of drinking water treatment processes. It can be used to predict the future water treatment situation which may happen or change. In water treatment plant Wim Mensink, the Stimela model train was set up to compare with other alternative water control strategies. Before starting the work of developing new water control strategies with Stimela model, Stimela model for Wim Mensink must be validated so that the model can be seen as a reliable and stable tool for the next work. Before the validation work, the current water control strategy for the treatment process needs to be investigated clearly to fulfil all the input control information is correct. Besides this, an experiment for obtaining the measured results of pellet diameters over different layers was performed in Wim Mensink. The validation work starts with single pellet softening process for three different reactors over first month from January 20th to February 20th. The fluidized bed height, pressure drop over total height of reactor, pellet diameters and porosities are validated. After that, the validation work is integrated with whole water treatment system to prove the function of pellet softening reactor and the four important water quality parameters over two important locations (after weir aerator location and final RO mixing location). The validated results of softening process are analysed by the relative error way to prove the reliability of the model results compared with measured results. The final step of the thesis work is developing the new water control strategies to optimize the current control plans of Wim Mensink. Five different water control strategies are put forward. They can be either reached separately according to their own advantages and limitations or fulfil with a step by step order as a whole optimization process. Moreover, the other water control strategies developed by engineering consultancy company DHV are evaluated here with Stimela model so that they can be proved reliable and achievable. In the future, the application of Stimela model will be spread over all the drinking water treatment plants in the Netherlands and contributes to the central automated control as a drinking water treatment operator training simulator.Sanitary EngineeringWatermanagementCivil Engineering and Geoscience
Use of Axle Load Spectra (ALS) for Estimating Calibration Drift in Weigh-In-Motion (WIM) Systems
No full textThis analysis's main objective is to determine WIM system errors based on axle loading without physically performing WIM equipment performance validation using test trucks. The presented methodology can be used to estimate systematic errors (calibration drift) in the WIM system at any point in time after the equipment calibration. This approach can help highway agencies select optimum timings for routine maintenance and calibration of WIM equipment without compromising its accuracy. The results show that the WIM accuracy for the single axle (SA) and tandem axle (TA) can be estimated with SA and TA NALS shape factors with an acceptable degree of error for bending plate (BP) and quartz piezo QP) sensors. The application and significance of the developed models were explained with the help of an example. The use of NALS to estimate the WIM system accuracy can save a significant amount of time and resources required for field validation of WIM performance every year.The presentation of the authors' names and (or) special characters in the title of the pdf file of the accepted manuscript may differ slightly from what is displayed on the item page. The information in the pdf file of the accepted manuscript reflects the original submission by the author
Investigation of Truck Weights and Dimensions Using WIM Data
No full textAbstractThis paper presents a study carried out with extensive weigh-in-motion (WIM) data collected on the French main road network, involving 3 millions of trucks. The data were collected by three WIM stations located on highly trafficked highways and motorways, continuously over a whole year. The data were analyzed using statistical software developed by the US National Science Foundation.The trucks of the traffic flow were classified into almost 20 categories, depending on the silhouette, number and spacing of axles, body configuration (trailer/semi-trailer), type of axles (steering, driving or standard axle) and wheel or tire (single, twin, wide). The data were analyzed by category.The location of the centre of gravity of the payload was calculated and the variability of its abscissa along the vehicle was analyzed in each category. The loading patterns and behavior were analyzed and the results reported here for 5-axle articulated trucks and 2-axle rigid truck with 2-axle trailer.Then, the axle load distributions were analyzed by axle rank and truck category, and modeled with multimodal Gaussian probability distribution functions. The modes have been determined using a maximum of likelihood method. These modes are useful to design endurance tests of truck tires.These investigations provide a better knowledge about truck loading, overloads and truck aggressiveness on infrastructure, and may lead to optimization policies. In this case, the results are used directly in the domain of tyre optimization
Correction: Do chemistry and rheology follow the same laboratory ageing trends in bitumen?
No full text Correction to: Materials and Structures (2022) 55:146 https://doi.org/10.1617/s11527-022-01986-w The article “Do chemistry and rheology follow the same laboratory ageing trends in bitumen?”, written by Georgios Pipintakos, Caitlin Lommaert, Aikaterini Varveri and Wim Van den bergh, was originally published in volume 55, issue 5, ID 146 without open access. With the society's decision to grant Open Choice the copyright of the article changed in February 2023 to © The Author(s) 2022 and the article is forthwith distributed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0. Open access funding enabled and organized by RILEM.Pavement Engineerin
Front Matter, Table of Contents, Preface, Conference Organization, External Reviewers, List of Authors
No full textFront Matter, Table of Contents, Preface, Conference Organization, External Reviewers, List of Author
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