Micrometric particles twodimensional self-assembly during drying of liquid film

We computed the self-organisation process of a monodisperse collection of spherical micrometric particles trapped in a two-dimensional (2D) thin liquid film isothermally dried on a chemically inert substrate. The substrate is either flat or indented to create linear stripes on its surface. The numerical results are illustrated and discussed in the light of experimental ones obtained from the drying of diamond particles water based suspension ($d_{50} = 10 \mu m$) on a glass substrate. The drying of the suspension on a flat substrate leads to the formation of linear patterns and small clusters of micrometric particles distributed over the whole surface of the substrate, whereas the drying of the suspension on a indented substrate leads to the aggregation of the particles along one side of the stripe which has a higher roughness than the other side of the stripe. This is an easy experimental way to obtain colloidal selforganized patterns.Comment: 16 pages 7 figure

Monte Carlo approach of the islanding of polycrystalline thin films

We computed by a Monte Carlo method derived from the Solid on Solid model, the evolution of a polycrystalline thin film deposited on a substrate during thermal treatment. Two types of substrates have been studied: a single crystalline substrate with no defects and a single crystalline substrate with defects. We obtain islands which are either flat (i.e. with a height which does not overcome a given value) or grow in height like narrow towers. A good agreement was found regarding the morphology of numerical nanoislands at equilibrium, deduced from our model, and experimental nanoislands resulting from the fragmentation of YSZ thin films after thermal treatment.Comment: 20 pages, 7 figure

Interface energies of (100)_{YSZ} and (111)_{YSZ} epitaxial islands on (0001)_{alpha-Al_2O_3} substrates from first principles

We present an ab initio study of the interface energies of cubic yttria-stabilized zirconia (YSZ) epitaxial layers on a (0001)_{alpha-Al_2O_3} substrate. The interfaces are modelled using a supercell geometry and the calculations are carried out in the framework of density-functional theory (DFT) and the local-density approximation (LDA) using the projector-augmented-wave (PAW) pseudopotential approach. Our calculations clearly demonstrate that the (111)_{YSZ} || (0001)_{alpha-Al_2O_3} interface energy is lower than that of (100)_{YSZ} || (0001)_{alpha-Al_2O_3}. This result is central to understanding the behaviour of YSZ thin solid film islanding on (0001)_{alpha-Al_2O_3} substrates, either flat or in presence of defects.Comment: 25 pages, 5 figures, 10 tables, submitted to Physical Review

Effect of the acrylic acid content on the permeability and water uptake of latex films

Acrylic acid (AA) is a monomer commonly employed in emulsion polymerization to provide electrostatic colloidal stability and improve specific film performance. The addition of AA not only modifies the kinetics of the polymerization, but also it takes part in the interaction between colloidal particles, which has a strong influence on their packing and consequent latex film properties. In this contribution a theoretical modeling of the latex film formation is presented and compared to experimental results: water vapor permeability and latex film capacitance are studied as a function of AA content. It has been shown that water uptake is mainly affected by film morphology which in turn is defined by intercolloidal interaction and drying rate.Comment: 16 pages, 7 figure

Quantitative fatigue fracture surface analysis on railway axles

International audienceFor passengers' safety and to improve railway axles maintenance, the French railway company, SNCF, studies the evolution of crack length in function of time in fatigue loading situations. To achieve this, it's necessary to know the in-service axle loading. As in-service measurements are very expensive and specific, authors decided to study fracture surfaces of components cracked or broken in service. So, the question is: how can we determine the loading history of a cracked component studying the fracture surfaces? This amounts to determining fracture mechanics parameters such as the maximum stress intensity factor Kmax along the crack path. Authors have ever transferred a quantitative fractographic analysis method from aluminium alloys to axle steel EA4T. This method is based on quantification of significant fractographic features such as striations. But, due to limits of this one, authors decided to add another technique based on X-ray diffraction measurements. In this paper, results of these methods are highlighted and discussed

Quantitative fatigue fracture surface analysis on railway axles

International audienceFor passengers' safety and to improve railway axles maintenance, the French railway company, SNCF, studies the evolution of crack length in function of time in fatigue loading situations. To achieve this, it's necessary to know the in-service axle loading. As in-service measurements are very expensive and specific, authors decided to study fracture surfaces of components cracked or broken in service. So, the question is: how can we determine the loading history of a cracked component studying the fracture surfaces? This amounts to determining fracture mechanics parameters such as the maximum stress intensity factor Kmax along the crack path. Authors have ever transferred a quantitative fractographic analysis method from aluminium alloys to axle steel EA4T. This method is based on quantification of significant fractographic features such as striations. But, due to limits of this one, authors decided to add another technique based on X-ray diffraction measurements. In this paper, results of these methods are highlighted and discussed

Experimental Study of the Rubber Cord Adhesion Inflation Test

An important property affecting the integrity of a tyre is the adhesion between rubber and reinforcements such as metal cords. Standard tests used to evaluate rubber-metal adhesion fail to predict the intrinsic interfacial behaviour. A novel test protocol, referred to as the Rubber Cord Adhesion Inflation Test (RCAIT), has therefore been developed. In this work, RCAIT is used to compare the performance of four different adhesive systems (two rubber types and two cord coatings). In addition, the effect of fluid injection rate on crack propagation pressure is evaluated and is correlated to the sensitivity of the tensile behaviour of the rubber to strain rate. Some improvements in the RCAIT analysis are also proposed here. A thick rubber tube inflation model is proposed in conjunction with the Ogden model for hyperelastic behaviour that can be applied to other elastomeric models as well. In conclusion, the relationship between crack propagation speed and Critical Strain Energy Release Rate (SERR) is discussed

Rubber Cord Adhesion Inflation Test: Effect of constitutive rubber model on evaluation of Gc

The Rubber Cord Adhesion Inflation Test (RCAIT) is a recently proposed test protocol to study tyre rubber-steel cord fracture (Kane et al., 2019). As in the traditional blister test, a pressurised fluid is injected between the two adherends to propagate fracture. The fracture energy, Gc, is directly related to the strain energy stored in the inflated rubber. It was shown that evaluation of Gc for RCAIT depends intimately on how well the hyperelastic model is capable of predicting the rubber inflation condition (Kane et al., 2020). Here, a thick tube inflation model is proposed for a generalised, phenomenological, hyperelastic material. It is subsequently applied to RCAIT in order to study which data processing technique is likely to be the most reliable to evaluate the critical strain energy release rate of the specimen