1,720,994 research outputs found
Laboratory and field investigation of grouted macadam for semi-flexible pavements
Full text linkGrouted macadam (GM) made of an open-graded asphalt skeleton whose air voids are filled with a cementitious grout, is used as wearing course in semi-flexible pavements. GM stands out for its high stiffness and rutting resistance, as well as for its chemical resistant and jointless surface. Although it could satisfy all the engineering properties requested by ports, airports and industrial pavements, there are still few applications worldwide and the mechanical characteristics have rarely been investigated in depth. The main objective of this paper is to compare the stiffness, fatigue resistance and the cracking propagation resistance of GM mixtures manufactured in the field and in the laboratory. The thermal susceptibility and the ravelling resistance of laboratory specimens were also evaluated. The findings show that the stiffening contribution of the grout improves the fatigue life especially at high deformation levels. However, due to the hardening of the asphalt skeleton caused by the ageing of the bitumen, GM mixture may exhibit a brittle behaviour. Considering the validation and correspondence between laboratory and field results, the data could be useful for establish some analytical pavement design criteria
Computational modeling of abdominal wall biomechanics in healthy, pathological and postsurgical conditions
No full textFinite element modeling of the abdominal wall biomechanics after hernia repair: the effects of muscle contraction
No full textRaveling Resistance of Grouted Macadam Compared to Conventional Asphalt Mixtures for Wearing Course
Full text linkGrouted macadam (GM), composed by a porous asphalt mixture whose air voids are filled with a cementitious grout, is efficiently used as wearing course in semi-flexible pavements subjected to heavy-load traffic and low speed. Since high steering angles, applied by vehicle load at low speed, induce high shear stresses on the surface, this research investigated the raveling resistance of GM in comparison with conventional asphalt mixtures usually employed in motorways and airports. Laboratory tests were carried out with the Darmstadt Scuffing Device, which simulates the actual in-field movement of a wheel during steering. Several environmental factors were simulated, varying the testing temperature and the conditioning of the specimens. Experimental results showed that GM ensures a satisfactory raveling resistance in the conditions of dry and wet surface, comparable with those of asphalt concretes. On the contrary, an outstanding behavior was registered for GM in the case of fuel spillage, thanks to its close structure which does not allow penetration and to the grout which guarantees chemical resistance
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Numerical modeling of the contractile behaviour of cardiomyocytes and their interaction with scaffolds
No full textFINITE ELEMENT MODELING OF ABDOMINAL WALL BIOMECHANICS AFTER HERNIA REPAIR: THE EFFECTS OF MUSCLE CONTRACTION
No full textUnderstanding the biomechanics of the abdominal wall is fundamental to address nonphysiological conditions like hernias. For this purpose, a computational approach is frequently proposed to assess how the abdominal wall interacts with surgical meshes, to support surgeons in the pre-operative planning. In this paper, numerical models of the abdominal wall are developed to evaluate the effect of muscle contraction on abdominal biomechanics after hernia repair. The geometry of the model is based on medical images from a healthy male subject. Fasciae, linea alba, and aponeuroses are modeled with hyperelastic fiber-reinforced constitutive models, while the contractile behavior of muscles is represented by a Hill-type three-element model. The effect of Intra-Abdominal Pressure (IAP) is simulated through a filled cavity. An epigastric hernia is modeled and virtually repaired with a surgical mesh. Numerical analyses are carried out at increasing IAP in both passive and active muscle states. The results show that surgical meshes reduce the compliance of the abdominal wall and this stiffening effect is more pronounced when considering abdominal contraction. This suggests that muscular contraction should be included in the computational models to mimic the effective mesh-abdomen interaction
- …
