A harsh, cold, and icy environment is of no surprise to the conditions of a winter climate, where the wide use of de-icing salts on roads and highways allows for the initiation of chloride-induced corrosion of the reinforcement of concrete structures; a reduced service life, loss of structural integrity, visible damages, and ultimately structural failure are among the many unwanted effects of rebar corrosion. Chloride ingress into concrete has been extensively studied for the last four decades; however, most of the relevant research to date does not take into account the effects of sustained loading on chloride transport properties. Therefore, the objectives of this study were to investigate the influence of sustained compressive and tensile stresses on chloride ingress into concrete, and ultimately to understand what the effect of sustained stress is on chloride penetration depth, on chloride concentration by % weight of concrete, and on apparent diffusion coefficients by comparing results to those of unloaded control specimens. To achieve these objectives, six post-tensioned and four non-reinforced control concrete beams were constructed with different water-to-cement (w/c) ratios and completely submerged in a 4-5% de-icing salt (NaCl) solution for 12 weeks, allowing chloride transfer to be completely governed by continuous diffusion. The effects of supplementary cementing material on chloride ingress are also studied. Concrete beams were post-tensioned to induce variable sustained compressive and tensile stresses along the beam. After 12 weeks of exposure, beams were fractured at specific locations and sprayed with a 0.1N silver nitrate (AgNO3) solution to determine average penetration depths; chloride concentration profiles were obtained from potentiometric titration of grinded powder samples. Apparent chloride diffusion coefficients were then obtained from the results of spraying AgNO3 and titration, the latter by non-linear regression curve-fitting to Fick’s second law of diffusion. A good agreement between results from both methods reveals that the use of AgNO3 in field is acceptable in predicting the rate of chloride ingress in concrete sustaining stress. The chloride diffusivity for each profile, relative to that of the unstressed section, was related to the compressive and tensile stresses in the concrete section. The experimental results indicate the dependence of chloride ingress and concentration on the type and level of sustained stress. An analysis of the results to study the effects of the w/c ratio using colourimetric (silver nitrate spray) and potentiometric titration methods was also completed.

Crushed or recycled concrete aggregates (CCA/RCA) is an increasingly popular material as a replacement for natural aggregates in concrete due to industry demands for more recycled, lower carbon and responsibly sourced materials. In the UK, the majority of CCA is utilised in non-structural applications such as: a general fill material, road base/subbase or in low-grade concrete. Recycled aggregate producers however, are seeking new ways to incorporate CCA into higher value applications such as structural concrete to increase profits. Opportunities to incorporate CCA into structural concrete may also arise because of project demands for sustainability or in situations where natural aggregates are in short supply. Limited research has been published regarding the effect of coarse CCA on the durability of structural concrete, particularly in respect to water and chloride ion ingress and possibility of corrosion initiation. The aim of this EngD research programme was to investigate the effect of coarse CCA and supplementary cementitious materials (SCMs) on the durability performance of structural concrete, with particular emphasis on the key liquid transport mechanisms within concrete, namely absorption by capillary action, diffusion and migration. This addressed an industry concern regarding the detrimental effect of coarse CCA which has resulted in a limit on replacement levels of coarse natural aggregates in structural concrete, as defined in Eurocodes and local national standards for concrete. In this study, structural concrete was produced with varying levels of coarse CCA replacement (up to 100%), from five different sources and/or structural elements across the UK, with various combinations of SCMs to replace in part the Portland cement. Petrographic analysis was used as an innovative technique to characterise the coarse CCA sources to determine suitability which yielded positive results. The durability performance of the resultant concrete was analysed by exposing the concrete to aggressive chloride environments. The results indicate that the inclusion of coarse CCA, even as low as 20%, had a detrimental effect on the durability performance of structural concrete, in relation to absorption by capillary action, diffusion and migration. This effect however, can be offset through the use of SCMs, which have been shown to outperform control Portland cement concrete with 100% natural aggregates in durability performance tests. The results also suggest that cementitious materials had a greater influence on durability performance than the type and source of coarse aggregates used. It is recommended that the replacement of natural aggregate with coarse CCA be limited to 30% in cases where compliance with the 28 day characteristic strength is of particular importance. If the criterion for compliance at 28 days can be relaxed and the compressive cube strength of concretes with SCMs tested at later ages for conformity (56 or 90 days), then higher quantities of coarse CCA may be incorporated up to 60% to produce a more sustainable structural concrete. It is recommended that Portland cement is partially replaced with 50% ground granulated blast-furnace slag (GGBS) to produce a CEM III/A concrete. This is a significant step towards the potential wider implementation of coarse CCA in structural concrete, provided a suitable quantity of SCM is adopted along with a reliable and consistent source of coarse CCA.

Ce travail de thèse vise à comprendre les effets des paramètres de conception de l'habitacle automobile tels que la hauteur de toit et la largeur du bavolet sur le mouvement d'entrée et de sortie et sur l'inconfort perçu. La méthode consiste à comparer expérimentalement des mouvements de moindre inconfort avec d'autres plus contraignants en modifiant la géométrie de l'habitacle. Grâce à un conformateur à géométrie variable, 5 configurations de postes de conduite sont définies sur 3 hauteurs d'assise représentant une sportive, une berline et un monospace. Le système optoélectronique Vicon et des capteurs d'efforts sont utilisés pour mesurer le mouvement et toutes les forces de contact, permettant une analyse fine des interactions entre les sujets et le conformateur. 26 sujets ont participé à l'expérimentation, dont la taille varie du 5ème percentile femme au 95ème homme. A l'aide d'un mannequin numérique, la cinématique (angles articulaires) et la dynamique (couples articulaires) du mouvement sont reconstruites. Les résultats montrent que l'exigence en hauteur de toit dépend peu de la stature et de la hauteur de siège. L'analyse biomécanique du mouvement révèle que les grandes statures présentent une plus forte flexion du tronc que les petites statures. Ceci peut s'expliquer par le fait que l'espace autour du siège est plus réduit pour les petites statures en raison de la position plus avancée du siège dans l'habitacle. Un abaissement de seulement 45mm du toit fait qu'un véhicule devient inacceptable pour le conducteur. Le volant joue un rôle essentiel pour l'accessibilité, pour produire le couple d'extension nécessaire au genou gauche pour s'extraire du véhicule / This PhD thesis aims at understanding the effects of the roof height and the sill width on the car ingress/egress motion and the perceived discomfort. The method consists in comparing experimentally the less constrained motion with more constrained ones by controlling design parameters. Thanks to an adjustable car mock-up, 3 configurations of roof height and sill width were tested by volunteers on three seat heights representing a small car, a medium-size car and a minivan. A Vicon motion capture system and 6-axes force sensors were used in order to measure the motion and all external contact forces and to allow an accurate analysis of the interactions between the driver and the car. 26 volunteers participated in the experiment, selected according to their stature in order to cover a large range of the French driver (from 5th percentile female to 95th percentile male). Using a Digital Human Model, the kinematics (joint angles) and the dynamics (joint torques) of the motion were reconstructed. The results show that the demand for the roof height is not influenced by the car configuration nor the volunteer‟s stature. A biomechanical analysis highlights that the short volunteers adopt a more upright trunk than the tall ones due to smaller space available between the seat and the steering wheel for short persons. In addition, a small change of 45 mm in roof height may lead to an unacceptable car configuration. Finally, the steering wheel is an essential car element helping drivers to produce the necessary extension torque at the left knee for getting up

This thesis describes searching for high-risk clusters of portals in the Ingress game by using data mining techniques. The work contains background for descibed problematics and methods and experiments used to search for theese information.

Der VHTR als Weiterentwicklung des HTR gilt als eines von sechs aussichtsreichen Reaktorkonzepten für Kernkraftwerkte der Generation IV. Im Rahmen dieser Arbeit wird ein CFD-Modell des HTR-Moduls entwickelt und durch die Simulation eines postulierten Lufteinbruchszenarios die Anwendbarkeit unter Beweis gestellt. Zunächst wird eine Bestandsaufnahme bestehender HTR-Rechenprogramme vorgestellt und die Methodik CFD in ihren Grundzügen erläutert. Anhand der Grundgleichungen werden die zur Berechnung des Störfalls zu modellierenden, HTR-spezifischen Parameter diskutiert, die verwendeten empirischen Korrelationen vorgestellt und die umfangreiche Validierung des entwickelten Modellansatzes zusammengefasst. Anschließend wird die Anwendbarkeit des HTR-Modells auf ein konkretes Lufteinbruchszenario eines HTR-Moduls gezeigt. Dabei werden die einzelnen Phasen des Szenarios anhand der Simulationsergebnisse intensiv diskutiert. Abschließend erfolgt eine Diskussion der Modellunsicherheiten und der numerischen Fehler.

A harsh, cold, and icy environment is of no surprise to the conditions of a winter climate, where the wide use of de-icing salts on roads and highways allows for the initiation of chloride-induced corrosion of the reinforcement of concrete structures; a reduced service life, loss of structural integrity, visible damages, and ultimately structural failure are among the many unwanted effects of rebar corrosion. Chloride ingress into concrete has been extensively studied for the last four decades; however, most of the relevant research to date does not take into account the effects of sustained loading on chloride transport properties. Therefore, the objectives of this study were to investigate the influence of sustained compressive and tensile stresses on chloride ingress into concrete, and ultimately to understand what the effect of sustained stress is on chloride penetration depth, on chloride concentration by % weight of concrete, and on apparent diffusion coefficients by comparing results to those of unloaded control specimens. To achieve these objectives, six post-tensioned and four non-reinforced control concrete beams were constructed with different water-to-cement (w/c) ratios and completely submerged in a 4-5% de-icing salt (NaCl) solution for 12 weeks, allowing chloride transfer to be completely governed by continuous diffusion. The effects of supplementary cementing material on chloride ingress are also studied. Concrete beams were post-tensioned to induce variable sustained compressive and tensile stresses along the beam. After 12 weeks of exposure, beams were fractured at specific locations and sprayed with a 0.1N silver nitrate (AgNO3) solution to determine average penetration depths; chloride concentration profiles were obtained from potentiometric titration of grinded powder samples. Apparent chloride diffusion coefficients were then obtained from the results of spraying AgNO3 and titration, the latter by non-linear regression curve-fitting to Fick’s second law of diffusion. A good agreement between results from both methods reveals that the use of AgNO3 in field is acceptable in predicting the rate of chloride ingress in concrete sustaining stress. The chloride diffusivity for each profile, relative to that of the unstressed section, was related to the compressive and tensile stresses in the concrete section. The experimental results indicate the dependence of chloride ingress and concentration on the type and level of sustained stress. An analysis of the results to study the effects of the w/c ratio using colourimetric (silver nitrate spray) and potentiometric titration methods was also completed.

This thesis describes searching for high-risk clusters of portals in the Ingress game by using data mining techniques. The work contains background for descibed problematics and methods and experiments used to search for theese information.

Dirt ingress in hydraulic cylinders is one of the sources that leads to pollution of hydraulic systems. There are already several test rigs to investigate external contamination mechanisms. However, until now only the behavior of the whole sealing system was analyzed. A new testing method to understand the dirt particle transport between a reciprocating motioned rod and a wiper is presented. The new approach aims to avoid known issues such as limited reproducibility and long duration. The paper describes the test rig design and operating principle. First measurement results are shown.

In Sweden, as in many other countries, preventive maintenance of structures andbridges is considered important. It provides several benefits such as prolonged lifespan or service life, less need for repair, and hopefully reduced costs and lowerenvironmental impact. A large part of Sweden’s bridge stock is getting quite old. The idea that small actionscan improve and/or prolong the status of the bridge and postpone needs for repairor prevent damage with a reduction in life cycle cost is generally in the owner’sinterest. One such preventive maintenance measure is the annual washing ofbridges. While clear positive effects have been observed on the expansion joints,drainage system, and the bridge’s visual appearance, an important question is howthe washing affects chloride ingress, mainly from de-icing salts, in reinforcedconcrete bridge members. The hypothesis is that the high-pressure washing cleansaway the contaminants on the surface and in the long run reduces the chloridecontent. While the practical experience has been positive in Sweden, no research hasyet been done concerning the effect of high-pressure washing on chloride ingress inconcrete bridges. A study has been conducted on the preventive bridge maintenance practice of theSwedish Transport Administration (STA) and Swedish municipalities. This work hasbeen based on a literature review, a survey of municipalities’ bridge maintenance,and practical participation with contractors during annual maintenance. Field andlaboratory tests were carried out on the effect of washing on chloride ingress in twotypes of concrete. A field station was installed on an edge beam of a bridge and wasfollowed over three years’ exposure including winter seasons, winter maintenance,and annual washing in June. Also, an accelerated test method was developed in thelaboratory to simulate the yearly exposure and test the effect of high- pressurewashing in a long-term simulation over just a few weeks. The practical aspects of bridge maintenance seem to be quite similar betweenSweden and in other countries. However, in terms of descriptions of and availablemeans for maintenance and repairs, there seem to be larger differences. For the fieldstation, the results after one year’s exposure do not show anything more than theanticipated difference in chloride ingress between the two concrete types understudy. For year two, a slight difference indicated that washed samples had a reducedchloride content. For year three, however, there was no distinct difference betweenivwashed and unwashed samples. The reasons for this need to be further investigatedand examined. This will be done in the continuous tests of field exposure. The laboratory test method has been developed and successively improved. The shape and levels of chloride ingress are reasonable and comparable with fieldsamples. However, there is a need to examine the effect of natural rain exposurewhich might have the same or greater effect of diluting the chloride content aswashing the surface once a year. Other factors also need to be considered, such aswhen and how often the maintenance is performed. A first step to be able to examinethis has been completed through the development of the accelerated test method. / I Sverige, som i många andra länder, anses förebyggande underhåll avkonstruktioner och broar vara viktigt. Det har flera fördelar, som att förlängalivslängden eller bruksskedet, minska behovet av reparationer och förhoppningsvisminska kostnader och miljöpåverkan. En stor del av Sveriges brobestånd börjar bli relativt gammalt. Det gör attförebyggande underhåll får mer uppmärksamhet och ges större vikt. Idén att mindreåtgärder kan förbättra och/eller förlänga standarden på bron och förskjuta behovetav reparationer eller förebygga skador med en minskning i livscykelkostnader ärgenerellt i ägarens intresse. En typ av förebyggande underhåll är den årligatvättningen av broar. Tydliga positiva effekter kan ses på fogar, dränering samt bronsvisuella intryck men en viktig fråga är hur tvättningen påverkar kloridinträngning från huvudsakligen tösalter i armerad betong. Hypotesen är att högtryckstvätt tarbort föroreningar på ytan, vilket på lång sikt minskar kloridmängden i betongen. Den praktiska erfarenheten ska ha varit positiv i Sverige, men ingen forskning har utförtspå vilken effekt högtryckstvättning har på kloridinträngningen i en bro av betong. En studie om det förebyggande brounderhållet hos Trafikverket och kommuner harutförts med hjälp av Trafikverkets och föregångarna Vägverkets dokument, annanlitteratur, en enkät till kommuner samt medverkan och observationer av detpraktiska vid utförandeentreprenaders årliga utförande av underhållet. Fält- ochlaboratorieprover för undersökning av tvättningens effekt på kloridinträngningenhar utförts. En fältstation på en kantbalk på en bro har installerats och följts undertre års exponering, med vinterklimat, vinterunderhåll samt årlig tvättning i juni. Enaccelererad provningsmetod har utvecklats för att simulera den årliga exponeringenoch undersöka effekterna av högtryckstvättning i en långtidssimulering på baranågra veckor. Ur praktisk synvinkel verkar brounderhåll vara ganska likt i Sverige och andraländer. Dock verkar beskrivningar och tillgängliga ekonomiska medel för underhålloch reparation visa större skillnader, vilket kan ha en stor påverkan på broarnasskadestatus. För fältstationen, är resultatet efter ett års exponering inte speciellttydligt förutom den förväntade skillnaden mellan de två undersökta betongtyperna(en äldre och en modern, mer beständig kvalitet). För år två syns en mindre skillnadmellan tvättade och otvättade prover. Skillnaden kan inte observeras i resultaten förår tre dock. Orsaken till detta måste undersökas vidare. Detta görs genom dekontinuerliga provningarna som fortsätter. Den accelererade provningsmetoden har utvecklats och kontinuerligt förbättrats.Formen och nivån på kloridinträngningen kan anses rimliga och jämförbara (påformen) med fältprover. Dock finns det ett behov av att undersöka påverkan avnaturligt regn vilket kanske har samma eller större effekt på att späda utkloridmängden som att högtryckstvätta ytorna en gång per år. Andra aspekterbehöver också undersökas, till exempel när och hur ofta underhållet ska utföras. Ettförsta steg att möjliggöra det har avslutats med utvecklingen av den accelereradeprovningsmetoden. / <p>QC 20220509</p> / Förebyggande Brounderhåll

Vid tillverkning av skåp för elkapsling har skydd mot vatten och damm stor betydelse. Tillgång till testutrustning som prövar skydd mot vatten och damm ger, effektivitet, kvalité och kostnadsbesparingar vid framtagning av elkapsling. Med högre prestation från företag kan större framsteg tas, där vinning finns gällande utveckling och miljöbesparing. Detta projekt har initierats då företaget Elkapsling AB insett behovet av egen testutrustning gällande vatten och dammskydd. Syftet var att uppnå besparing av tid och kostnader gällande testning av egen produkt. Projektet är genomfört som ett examensarbete för Maskiningenjörutbildningen (TMPRG) på Mittuniversitet (Mid Sweden University) i Östersund. Målet var att framta underlag av konstruktion för utrustning åt Elkapsling AB som uppfyller de krav och önskemål de har givit. Utrustningen var framtagen med hjälp av produktutvecklingsmetodik i projektfaser där framstegen från milstolparna redovisades i form av avstämning med Elkapsling AB spontant efter behov under projektets gång. Projektets resultat kommer i form av konstruktionsunderlag av en dammkammare för testning av dammskydd, verktyg för testning av vattenskydd samt förslag på lösningar av återanvändning av vatten. Detta skapar förutsättningar av effektivitet långsiktig besparing av pengar. Detta kan bidra även till effektivare framtagning av förbättrade produkter från Elkapsling AB. Innan utrustning kan konstrueras krävs tester och mer standardiseringar av komponenter och andra anpassningar efter Elkapsling AB egna behov. Den ekonomiska uppskattningen borde utvecklas till en mer omfattande kalkyl för att ge en bättre uppskattning över projektet riktiga kostnad i helhet / Protection against water and dust is very important in the manufacture of enclosures for electrical enclosures. Access to testing equipment that tests for water and dust protection provides efficiency, quality and cost savings in the production of electrical enclosures. With higher performance from companies, greater progress can be made, with benefits in terms of development and environmental savings. This project has been initiated when the company Elkapsling AB realised the need for its own testing equipment regarding water and dust protection. The aim was to save time and costs for testing of own products. The project is carried out as a degree project for the Mechanical Engineering Program (TMPRG) at Mid Sweden University in Östersund. The goal was to produce a design for equipment for Elkapsling AB that meets the requirements and wishes they have given. The equipment was developed using product development methodology in project phases where progress from milestones was reported in the form of reconciliation with Elkapsling AB spontaneously as needed during the course of the project. The results of the project come in the form of design documentation of a dust chamber for testing dust protection, tools for testing water protection and proposed solutions of water reuse. This creates conditions of efficiency and long-term saving of money. This can also contribute to more efficient production of improved products from Elkapsling AB. Before equipment can be realized, tests and more standardization of components and other adaptations to Elkapsling AB's own needs are required. The financial estimate should be developed into a more comprehensive calculation to give a better estimate of the true cost of the project as a whole. / <p>2022-07-01</p>