Effect of base bitumen composition on asphalt rubber binder properties

The asphalt rubber blend properties are strongly related to its base components properties. The base bitumen composition is considered as a key factor influencing the final rheological properties of asphalt rubber binder. This paper describes results from a laboratory investigation of the interaction between crumb rubber and different composition bitumen according to the wet process. The bitumen composition is determined according to the SARA decomposition approach. The composition’s analyses are carried out on both base bitumen and residual bitumen extracted from the final asphalt rubber blend. The extraction process consists of a centrifuging procedure ensuring a reasonable aging and a minimum physical or chemical alteration of the phases. The evolution of the bitumen composition during the curing process indicates that aromatic fractions of bitumen are the major cause of rubber swelling through a migration phenomenon. Viscoelastic properties measurements demonstrate that base bitumen composition should be selected carefully to achieve a good compromise between a sufficient rubber swelling and a reasonable viscosity of the final binder

Budgeting Under-Specified Tasks for Weakly-Hard Real-Time Systems

In this paper, we present an extension of slack analysis for budgeting in the design of weakly-hard real-time systems. During design, it often happens that some parts of a task set are fully specified while other parameters, e.g. regarding recovery or monitoring tasks, will be available only much later. In such cases, slack analysis can help anticipate how these missing parameters can influence the behavior of the whole system so that a resource budget can be allocated to them. It is, however, sufficient in many application contexts to budget these tasks in order to preserve weakly-hard rather than hard guarantees. We thus present an extension of slack analysis for deriving task budgets for systems with hard and weakly-hard requirements. This work is motivated by and validated on a realistic case study inspired by industrial practice

New Method for Pavement Rutting Prediction

In recent years, pavement rutting rate has increased significantly due to constant traffic intensity increment. These solicitations affect the bituminous layers that can quickly attain their permanent deformation limit resistance. This phenomenon can lead to a pavement depression, located in the tyre-road contact surface. The purpose of this paper is to present a methodology to estimate the rutting of bituminous pavements and to predict the rutting risk considering the bituminous mix rutting resistance characteristics obtained with the LPC traffic simulator, and taking into account the traffic and environmental characteristics. The traffic characteristics are represented by the total heavy traffic expressed in equivalent single axle loads (ESAL) passed on the pavement during the service period, and the heavy vehicles speed on the considered section. The environmental characteristic is represented by the pavement temperature at 2 cm depth. The developed model starts from the widely used empirical rutting formula and its experimentally determined coefficients. The general concept of the model is to start from this generalised rutting formula and to apply it to the real rutting behaviour occurring in pavements. For this purpose, observations and material analysis of eleven in place pavements were made. The model was calibrated using eleven bituminous mixes and verified introducing the characteristics of four in place bituminous mixes not considered in the initial calibration phase. The developed model gives rut depth values after having determined material and site characteristics and presents a good correlation coefficient with very satisfactory results in its verification phase with additional materials

Elaboration d'un plan des classes de trafic pondéral du réseau routier de la ville de Lausanne

La présente étude vise à fournir une analyse du trafic lourd présent sur le réseau routier de la ville de Lausanne et établir la classe de trafic pondéral de chacune des routes du réseau principal. Le rapport établi donne les explications nécessaires à la compréhension de la démarche et à l’utilisation du fichier Excel « Détails de la détermination des CT » qui constitue l’élément principal de l’étude. Ce fichier contient toutes les étapes depuis le recensement des différents bus par tronçon de route jusqu’à la détermination de la classe de trafic, il reprend l’ensemble des données et donne les résultats obtenus

High modulus pavement design using accelerated loading testing (ALT)

In anticipation of the introduction of high modulus materials in the Swiss standards, a research project has been carried out for the evaluation of these bituminous mixtures. Three full-size test sections were built in a test hall for ALT named Halle-fosse: Two sections with two different high modulus bituminous mixtures (named EME, abbreviation of the French designation of the mixture: Enrobé à Module Elevé) as base layer, whereas the third section, used as reference, had a standard bituminous material base layer. The three structures were designed to have an equivalent fatigue resistance and were submitted to loading with a traffic simulator. This device, a truck axle, permits to simulate heavy traffic on roads. Strains were measured for different types of loading at different temperatures, in order to assess the response of the structure. Equivalency factors for both types of EME mixtures were established using, as a basis, the French design method

Flutter analysis of a morphing wing technology demonstrator : numerical simulation and wind tunnel testing

As part of a morphing wing technology project, the flutter analysis of two finite element models and the experimental results of a morphing wing demonstrator equipped with aileron are presented. The finite element models are representing a wing section situated at the tip of the wing; the first model corresponds to a traditional aluminium upper surface skin of constant thickness and the second model corresponds to a composite optimized upper surface skin for morphing capabilities. The two models were analyzed for flutter occurrence and effects on the aeroelastic behaviour of the wing were studied by replacing the aluminium upper surface skin of the wing with a specially developed composite version. The morphing wing model with composite upper surface was manufactured and fitted with three accelerometers to record the amplitudes and frequencies during tests at the subsonic wind tunnel facility at the National Research Council. The results presented showed that no aeroelastic phenomenon occurred at the speeds, angles of attack and aileron deflections studied in the wind tunnel and confirmed the prediction of the flutter analysis on the frequencies and modal displacements

Bounding Deadline Misses in Weakly-Hard Real-Time Systems with Task Dependencies

International audienceReal-time systems with functional dependencies between tasks often require end-to-end (as opposed to task-level) guarantees. For many of these systems, it is even possible to accept the possibility of longer end-to-end delays if one can bound their frequency. Such systems are called weakly-hard. In this paper we provide end-to-end deadline miss models for systems with task chains using Typical Worst-Case Analysis (TWCA). This bounds the number of potential deadline misses in a given sequence of activations of a task chain. To achieve this we exploit task chain properties which arise from the priority assignment of tasks in static-priority preemptive systems. This work is motivated by and validated on a realistic case study inspired by industrial practice and derived synthetic test cases

Regulation of Embryonic and Induced Pluripotency by Aurora Kinase-p53 Signaling

SummaryMany signals must be integrated to maintain self-renewal and pluripotency in embryonic stem cells (ESCs) and to enable induced pluripotent stem cell (iPSC) reprogramming. However, the exact molecular regulatory mechanisms remain elusive. To unravel the essential internal and external signals required for sustaining the ESC state, we conducted a short hairpin (sh) RNA screen of 104 ESC-associated phosphoregulators. Depletion of one such molecule, aurora kinase A (Aurka), resulted in compromised self-renewal and consequent differentiation. By integrating global gene expression and computational analyses, we discovered that loss of Aurka leads to upregulated p53 activity that triggers ESC differentiation. Specifically, Aurka regulates pluripotency through phosphorylation-mediated inhibition of p53-directed ectodermal and mesodermal gene expression. Phosphorylation of p53 not only impairs p53-induced ESC differentiation but also p53-mediated suppression of iPSC reprogramming. Our studies demonstrate an essential role for Aurka-p53 signaling in the regulation of self-renewal, differentiation, and somatic cell reprogramming

Improving PBL in Empowering Meta cognitive Skill of Students

Abstract Objective: Problem-Based Learning (PBL) is a potential constructivist learning strategy that empowers students’ Meta cognitive skill. PBL focuses on problem, involves thinking activity to solve problems, and correlates to cognitive function of students. Methods: The implementation of PBL reveals various benefits, but there are also some weaknesses in this learning strategy. Thus, it is necessary to implement a certain learning strategy that can cover the PBL weaknesses, such as Reading, Questioning, and Answering (RQA) learning strategy. RQA is a new learning strategy developed based on a fact that almost all students do not read the next lecture materials, causing failure of learning strategy planned and finally the students’ comprehension becomes low. RQA is also potential to empower students’ Meta cognitive skill. Findings: The integration of RQA and PBL learning strategy is called PBL-RQA learning strategy. This study was a quasi-experimental study designed to compare the effect of PBL, RQA, and PBL-RQA learning strategies on the students’ Meta cognitive skill of Faculty of Mathematics and Science, State University of Makassar. Application: The results of the study showed that the potency of PBL learning strategy in empowering the students’ Meta cognitive skill has been increased by integrating it to RQA learning strategy. The meta cognitive skill mean score of the students taught by PBL-RQA learning strategy was 21% higher than that of the students taught by PBL and 26.9% higher than that of the students taught by RQA learning strategy. Keywords: Answering, Meta Cognitive Skill, Problem-Based Learning, Questioning, Reading, PBL-RQ

VARIATIONS SPATIO-TEMPORELLES DE LA SECHERESSE CLIMATIQUE EN ALGERIE NORD-OCCIDENTALE

L’Algérie a connu, au cours de ces vingt dernières années, une sécheresse intense et persistante. Cette sécheresse, caractérisée par un important déficit pluviométrique, a touché l’ensemble de l’Algérie et plus particulièrement sa partie nord-occidentale. Des sécheresses analogues, aussi bien en amplitude qu’en intensité, ont déjà été observées au début du 20éme siècle, entre 1910 et 1940. Dans cette étude nous nous sommes intéressés à une analyse historique de la sécheresse climatique à l’échelle annuelle, afin de suivre son évolution par décennies, de 1920 à 1990. Nous essayerons de caractériser cette sécheresse, de la quantifier et enfin d’étudier sa variation spatio-temporelle. Ce travail a été réalisé à l’aide de deux approches : L’étude du déplacement du sud vers le nord de l’isohyète 400 mm, qui met en évidence l’ampleur de l’extension géographique du phénomène. L’analyse cartographique automatique de l’indice pluviométrique centré-réduit de sept décennies (de 1920 à 1990), mettant en évidence l’importance de l’évolution vers le nord de cet indice Algerian has witnessed during the last twenty years an intense and persistent drought. This drought which is characterized by an important rainfall deficit has affected the whole of Algeria particularly the north - west part.Similar droughts in amplitude and intensity have yet been noticed at the beginning of the century, between 1910 and 1940. In our study we devoted ourselves to historical analysis of drought on the annual scale. This has allowed us to follow its evolution decade by decade from 1920 to 1990. We tried in the first step to characterize this drought. Then to quantify it and at last to study its variability in space through two approach methods: calculation of the advance of the South to the North, the isohyet 400mm, which stresses the importance of the geographical extension of the phenomenon, and the automatic cartography of the rainfall indications per decade from 1920 to 199