scholarly journals Wear biomechanics in the slicing dentition of the giant horned dinosaurTriceratops

2015 ◽  
Vol 1 (5) ◽  
pp. e1500055 ◽  
Author(s):  
Gregory M. Erickson ◽  
Mark A. Sidebottom ◽  
David I. Kay ◽  
Kevin T. Turner ◽  
Nathan Ip ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Dental Morphology ◽  
Wear Properties ◽  
Wear Model ◽  
Ecological Diversification ◽  
Dental Tissues ◽  
Plant Matter ◽  
Central Regions ◽  
Processing Plants ◽  
Ceratopsian Dinosaurs

Herbivorous reptiles rarely evolve occluding dentitions that allow for the mastication (chewing) of plant matter. Conversely, most herbivorous mammals have occluding teeth with complex tissue architectures that self-wear to complex morphologies for orally processing plants. Dinosaurs stand out among reptiles in that several lineages acquired the capacity to masticate. In particular, the horned ceratopsian dinosaurs, among the most successful Late Cretaceous dinosaurian lineages, evolved slicing dentitions for the exploitation of tough, bulky plant matter. We show howTriceratops, a 9-m-long ceratopsian, and its relatives evolved teeth that wore during feeding to create fullers (recessed central regions on cutting blades) on the chewing surfaces. This unique morphology served to reduce friction during feeding. It was achieved through the evolution of a complex suite of osseous dental tissues rivaling the complexity of mammalian dentitions. Tribological (wear) properties of the tissues are preserved in ~66-million-year-old teeth, allowing the creation of a sophisticated three-dimensional biomechanical wear model that reveals how the complexes synergistically wore to create these implements. These findings, along with similar discoveries in hadrosaurids (duck-billed dinosaurs), suggest that tissue-mediated changes in dental morphology may have played a major role in the remarkable ecological diversification of these clades and perhaps other dinosaurian clades capable of mastication.

Internal reconstruction of elephantid molars: applications for functional anatomy and systematics

Paleobiology ◽  
1995 ◽  
Vol 21 (3) ◽  
pp. 379-392 ◽  
Author(s):  
David J. Froehlich ◽  
Jon E. Kalb
Keyword(s):  
Functional Anatomy ◽  
Three Dimensional ◽  
Dental Morphology ◽  
Systematic Analysis ◽  
Functional Studies ◽  
Three Dimensional Modeling ◽  
Dimensional Modeling ◽  
The Family ◽  
Replacement Pattern ◽  
Unique Manner

The unique manner in which molars from members of the family Elephantidae erupt in the jaw and wear obliquely and sequentially has profound effects upon dental function and phylogenetic change within the group. Three-dimensional modeling using a “molar matrix” of elephantid dentition, and application of such models to systematic and functional studies, allows a more refined description of dental morphology. A method of examining variation within elephantid teeth is presented based on successive staging of worn molars. Results indicate that individual plates exhibit increasingly derived features with wear (relative to the systematic analysis used here), while successively worn plates exhibit successively more plesiomorphic features apically and posteriorly. Further, results indicate that the patterns developed by wear on the surface of elephantid molars are conserved throughout life despite their unique successive replacement pattern. The cheek teeth in a molar series act as a single, continuous masticating unit, here termed a “cheek tooth battery.” Overall, the tools developed here, wear staging and molar matrices, allow for a more refined understanding of morphological variation within and between elephantids, with application to more conservative elephantoid taxa.

BPNN-QSTR Models for Triazine Derivatives for Lubricant Additives

2019 ◽  
Vol 142 (1) ◽  
Author(s):  
Tingting Wang ◽  
Zhan Wang ◽  
Hao Chen ◽  
Kang Dai ◽  
Xinlei Gao
Keyword(s):  
Tribological Properties ◽  
Back Propagation ◽  
Three Dimensional ◽  
Predictive Ability ◽  
Quantitative Relationship ◽  
Molecular Structures ◽  
Lubricant Additives ◽  
Extreme Pressure ◽  
Wear Properties ◽  
Triazine Derivatives

Abstract Triazine derivatives are a kind of lubricant additives with excellent tribological properties. It is of great significance to study the quantitative relationship between their chemical structure and tribological properties. In the present study, the quantitative structure tribo-ability relationships (QSTR) between 20 triazine derivatives and their respective extreme-pressure properties as lubricant additives were analyzed by the back propagation neural network (BPNN) method. The BPNN-QSTR model had satisfactory stability and predictive ability (R2 = 0.9965, R2(LOO) = 0.9195, q2 = 0.8274). The anti-wear model also yielded good predictions (R2 = 0.9757, R2(LOO) = 0.6261, q2 = 0.8022). Two- and three-dimensional structural descriptors were used to analyze molecular structures that affected extreme-pressure and anti-wear properties. The results indicate that the three-dimensional molecular dimensions and the bonding modes of the skeleton atoms in the molecules were important factors. In addition, the effects of N, P, O, and other hetero-atoms on the tribological properties were reflected in their corresponding group types and electronic structures.

Modelling the Effects of Head Diameter and Cup Wall Thickness on Contact Mechanics and Wear of Cross-Linked UHMWPE Cups

2005 ◽  
Author(s):  
Lu Kang ◽  
Alison L. Galvin ◽  
Zhongmin Jin ◽  
John Fisher
Keyword(s):  
Wall Thickness ◽  
Three Dimensional ◽  
Volumetric Wear ◽  
Wear Model ◽  
Wear Factor ◽  
Head Diameter ◽  
Maximum Contact ◽  
Ultra High Molecular Weight ◽  
Outside Diameter

A three-dimensional contact-coupled wear model was developed and used to predict the long-term wear in both conventional and cross-linked ultra high molecular weight polyethylene (UHMWPE) cups, particular to examine the effect of the head diameter and the UHMWPE cup wall thickness. The wear factors were determined from the simulator testing of 28 mm diameter cups. The maximum contact pressure was found to decrease with the increase of head diameter up to 48 mm, corresponding to the decrease in the cup wall thickness for a fixed outside diameter of the cup. Volumetric wear rate was predicted to increase as the head size increased for the conventional UHMWPE, as well as the cross-linked UHMWPE, although at a much lower rate for the latter due to the smaller wear factor.

Friction and Wear Properties of Al-Based Hypereutectic Silicon Coatings Fabricated by Supersonic Particles Deposition on ZM5 Magnesium Alloy

2014 ◽  
Vol 952 ◽  
pp. 125-129
Author(s):  
Xiao Jun Shi ◽  
Hai Bo Jiang ◽  
Ju Kun Yao ◽  
Zhi Qian Wang ◽  
Chao Ji Zhou ◽  
...  
Keyword(s):  
Magnesium Alloy ◽  
Testing Machine ◽  
Three Dimensional ◽  
Micro Hardness ◽  
Wear Properties ◽  
Hardness Tester ◽  
Wear Protection ◽  
Resistant Layer ◽  
Mechanical Bonding ◽  
Abrasion Testing

To improve the anti-wear properties of Mg alloys, Al-13Si, Al-15Si and Al-19Si coatings were prepared by supersonic particles deposition on the surface of ZM5 magnesium alloy. Micro-structure and anti-wear properties of the coatings were examined by digital micro-hardness tester, XRD, friction and abrasion testing machine, three-dimensional microscope and SEM. The results show that the wear-resistant layer and the magnesium substrate can be well integrated as mechanical bonding and the main wear failure mechanism of the three coatings is adhesive wear. Moreover, the micro-hardness of Al-19Si coating is 141.47HV0.05, much higher than Al-13Si coating (134.97HV0.05) and Al-15Si coating (136.02HV0.05). Besides, the anti-wear properties of Al-19Si coating is optimal, superior to Al-15Si coating and Al-13Si coating. All of those indicate that Al-19Si coating can provide the most excellent anti-wear protection for ZM5 magnesium alloy.

An Abrasive Wear Model of Interpenetrating Composites

2008 ◽  
Vol 575-578 ◽  
pp. 1329-1334
Author(s):  
Shou Ren Wang ◽  
Pei Quan Guo ◽  
Hong Yan Wang ◽  
Min Wang
Keyword(s):  
Abrasive Wear ◽  
Volume Content ◽  
Functional Materials ◽  
Structure Characteristic ◽  
Mixing Rule ◽  
Wear Properties ◽  
Wear Model ◽  
Elastic Module ◽  
Attractive Candidate ◽  
Two Phases

Owing to two phases are continuous and penetrated each other, Interpenetrating composites exhibit good abrasive wear properties, can be an attractive candidate for structural and functional materials. Specifically, the abrasive wear model of IPCs is an important topic in the field of tribology. In present work, the model has been proposed according to the mixing rule. Many factors such as special topology structure characteristic of reinforcement, hardness and elastic module are discussed in this model. One kind of Al2O3/Mg composite with different volume content was fabricated and many test data of friction wear were obtained. These data validate the correctness and universality of model.

scholarly journals Wear Processes in a Mechanical Friction Clutch: Theoretical, Numerical, and Experimental Studies

2015 ◽  
Vol 2015 ◽  
pp. 1-28 ◽  
Author(s):  
Dariusz Grzelczyk ◽  
Jan Awrejcewicz
Keyword(s):  
Mathematical Modeling ◽  
Experimental Data ◽  
Numerical Analysis ◽  
Numerical Simulations ◽  
Experimental Studies ◽  
Friction Torque ◽  
Wear Properties ◽  
Wear Model ◽  
Differential Model ◽  
Friction Clutch

Mathematical modeling, theoretical/numerical analysis, and experimental verification of wear processes occurring on the contact surface of friction linings of a mechanical friction clutch are studied. In contrast to many earlier papers we take into consideration wear properties and flexibility of friction materials being in friction contact. During mathematical modeling and numerical simulations we consider a general nonlinear differential model of wear (differential wear model) and a model of wear in the integral form (integral wear model). Equations governing contact pressure and wear distributions of individual friction linings, decrease of distance between clutch shields, and friction torque transmitted by the clutch are derived and compared with experimental data. Both analytical and numerical analyses are carried out with the qualitative and quantitative theories of differential and integral equations, including the Laplace transform approach to ODEs. We show that theoretical results and numerical simulations agree with the experimental data. Finally, a numerical analysis of the proposed mathematical models was carried out in a wider range of parameters of the considered system.

The assembly of the synaptinemal complex

1977 ◽  
Vol 277 (955) ◽  
pp. 235-243 ◽  
Keyword(s):  
Central Region ◽  
Three Dimensional ◽  
Chiasma Formation ◽  
Central Component ◽  
Lateral Component ◽  
Late Zygotene ◽  
Homologous Chromosomes ◽  
Synaptinemal Complex ◽  
Central Regions ◽  
Dimensional Reconstruction

The assembly of the synaptinemal complex in the ascomycete Neottiella was studied by three-dimensional reconstruction of a late zygotene nucleus. A single banded lateral component is formed between the two sister chromatids of each homologous chromosome prior to their pairing. The central regions are pre-assembled in organized form in folds of the granular part of the nucleolus and then converted into an amorphous transport form. The latter appears to move through the nucleoplasm to sites between the lateral components of synapsing homologous chromosomes. The central region material is reorganized into blocks with a recognizable central component and attached to one lateral component. The last step in the completion of the synaptinemal complex is the association of the free surface of the organized central region with the corresponding segment of the homologous lateral component. The findings are discussed in relation to mechanisms of chromosome pairing and chiasma formation.

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