Arthur Francisco

Université de Poitiers | UP · DUT Qualité, Logistique Industrielle et Organisation (QLIO)

This study aims at improving dietary discrimination among primates through a new analytic approach of dental microwear texture analysis integrating a surface sampling on facets of both phase I and II of mastication. The surface sampling is applied on these two types of molar facets on 104 specimens belonging to four extant cercopithecids, and on 20...

This paper presents a numerical analysis of the hydrodynamic pressure build-up between parallel surfaces. According to the Reynolds theory, it is not possible to generate a pressure between flat parallel sliding surfaces. However, experimental results demonstrate that mechanical seal surfaces can be separated by a full fluid film if the sliding spe...

This paper presents a multiscale finite element method applied to the simulation of a lubricating film flowing between rough surfaces. The objective of this approach is to study flows between large rough surfaces needing very fine meshes while maintaining a reasonable computation time. For this purpose, the domain is split into a number of subdomai...

Modern surface acquisition devices, such as interferometers and confocal microscopes, make it possible to have accurate three-dimensional (3D) numerical representations of real surfaces. The numerical dental surfaces hold details that are related to the microwear that is caused by food processing. As there are numerous surface parameters that descr...

Here, we present a short review of the most recent results that have come out of the TRIDENT project. This project aims to model tooth wear by performing controlled food testing on sheep. This approach offers us the opportunity to test various scientific questions which colleagues, working exclusively on fossil and modern wild species, have been un...

Tooth wear and, more specifically, dental microwear texture is a dietary proxy that has been used for years in vertebrate paleoecology and ecology. DMTA, dental microwear texture analysis, relies on a few parameters related to the surface complexity, anisotropy and heterogeneity of the enamel facets at the micrometric scale. Working with few but ph...

Both dust and silica phytoliths have been shown to contribute to reducing tooth volume during chewing. However, the way and the extent to which they individually contribute to tooth wear in natural conditions is unknown. There is still debate as to whether dental microwear represents a dietary or an environmental signal, with far-reaching implicati...

Appendix S3. Asfc distribution according to specimen age and according to dietary group: clover (in green); chestnuts (in red); corn (in blue); barley (in black).

Appendix S2. Photosimulations of the enamel surfaces scanned with the Leica DCM8 surface profilometer for each of the 40 ewes.

Appendix S4. Canonical discriminant analysis. Posterior individual probabilities for the CDA comparing clover‐fed and seed‐fed ewes (a) and comparing the four dietary categories (b).

Appendix S1. List of ewes (specimen number and known age) clustered into their dietary groups with individuals raw dental microwear textural parameters.

While grazing as a selective factor towards hypsodont dentition on mammals has gained a lot of attention, the importance of fruits and seeds as fallback resources for many browsing ungulates has caught much less attention. Controlled-food experiments, by reducing the dietary range, allow for a direct quantification of the effect of each type of ite...

Both dust and silica phytoliths have been shown to contribute to reducing tooth volume during chewing. However, the way and the extent to which they individually contribute to tooth wear in natural conditions is unknown. There is still debate as to whether dental microwear represents a dietary or an environmental signal, with far reaching implicati...

Supplementary material

Since many years, the pioneering work of Hu and Tonder is used to generate rough surfaces with prescribed statistical moments (skewness and kurtosis) along with spatial properties (correlation lengths). The present work enlightens the drawbacks of this method and it proposes an original approach based on a hybrid analytical/numerical method. Simula...

From a very general point of view, optimization involves numerous calculations and therefore a high computational cost. In the fields where a single calculation is long and the optimization is crucial, specific techniques, devoted to this task, have been developed. First, the surrogate-based models are introduced and a short review of optimization...

The numerical optimization of the connecting rod big-end lubrication involves several main steps. The first, which can be considered as the most important one, is the identification of the main input factors and their varying range. In the same time, the meaningful resulting values have to be identified because the optimization will be performed on...

The background of the present study is the rolling contact fatigue (RCF) in a brittle polymer disk. The disk has been tested on a two disk machine, under controlled normal and tangential loads, with no global slip. After several million cycles and under different operating conditions, it has been observed that (1) the tangential load highly influen...

Despite the numerous experimental works on rolling contact fatigue, dealing with two-disk contacts, some phenomena still remain badly understood. Most of the test benches, used for that purpose, impose the rotational speeds to the disks: global slipping occurs and the tangential force is measured. Even if this configuration is found in some mechani...

Country-Specific Mortality and Growth Failure in Infancy and Yound Children and Association With Material Stature Use interactive graphics and maps to view and sort country-specific infant and early dhildhood mortality and growth failure data and their association with maternal

The present work aims to identify the most influent factor in the behavior of a connecting rod big-end bearing. Supposing that the structure and the operating conditions are given, ten input parameters (oil properties, shells geometry, [[ellipsis]]) have been kept for this study. If the parameters can vary between a low and a high value, it would a...

Ceramic materials are often used in tribological applications because of their good mechanical properties. Silicon carbide (SiC) has a low density, high Young's modulus, high corrosion resistance, and very low friction in water. It is a very good candidate for replacing waterproof oil-lubricated bearings in water pumps and for applications when wat...

The aim of this work is to obtain the numerical solution of the isothermal elastohydodynamic lubrication problem for the finite line contact using high modulus material and very low viscous lubricant (Silicon Carbide lubricated with water). Generally, the cylinder length is assumed to be infinite, so the results are obtained within the field of pla...

Reprenant l'idée d'une expérimentation de Kaneta et Murakami (1986), nous utilisons une machine bi-disques comportant un galet éprouvette fragile transparent, pour étudier le phénomène de fatigue de contact de roulement. Ce choix nous permet d'observer clairement les fissures aussi bien en surface, ce qui est traditionnel, qu'en profondeur dans la...