Papers by Robert O Ritchie
Nature communications, Feb 16, 2024
Journal of Bone and Mineral Research, Feb 1, 2009
Biomaterials, Jul 1, 2010
Research Square (Research Square), May 16, 2023
Metallurgical transactions, Mar 1, 1988
Metallurgical transactions, Mar 1, 1988
Nature Communications
High-performance, fast-growing natural materials with sustainable and functional features current... more High-performance, fast-growing natural materials with sustainable and functional features currently arouse significant attention. Here, facile processing, involving delignification, in situ hydrothermal synthesis of TiO2 and pressure densification, is employed to transform natural bamboo into a high-performance structural material. The resulting TiO2-decorated densified bamboo exhibits high flexural strength and elastic stiffness, with both properties more than double that of natural bamboo. Real-time acoustic emission reveals the key role of the TiO2 nanoparticles in enhancing the flexural properties. The introduction of nanoscale TiO2 is found to markedly increase the degree of oxidation and the formation of hydrogen bonds in bamboo materials, leading to extensive interfacial failure between the microfibers, a micro-fibrillation process that results in substantial energy consumption and high fracture resistance. This work furthers the strategy of the synthetic reinforcement of fas...
arXiv (Cornell University), Oct 3, 2022
Research Square (Research Square), May 25, 2022
Materials Research Letters, 2020
Science, 2020
Strong and tough steel Ultrahard materials often do not have similarly impressive fracture toughn... more Strong and tough steel Ultrahard materials often do not have similarly impressive fracture toughness. Liu et al. discovered a processing route for medium manganese steel alloy in which ultrahigh strength accompanies high fracture toughness. The steel relies on both transformation-induced plasticity and delamination toughening to boost the fracture properties. The steel is composed of less expensive elements, making it a potentially inexpensive material attractive for structural applications. Science , this issue p. 1347
Advanced Functional Materials, 2019
Keratin is one of the most common structural biopolymers exhibiting high strength, toughness, and... more Keratin is one of the most common structural biopolymers exhibiting high strength, toughness, and low density. It is found in various tissues such as hairs, feathers, horns, and hooves with various functionalities. For instance, horn keratin absorbs a large amount of energy during intraspecific fights. Keratinized tissues are permanent tissues because of their basic composition consisting of dead keratinized cells that are not able to remodel or regrow once broken or damaged. The lack of a self‐healing mechanism presents a problem for horns, as they are under continued high risk from mechanical damage. In the present work, it is shown for the first time that a combination of material architecture and a water‐assisted recovery mechanism, in the horn of bighorn sheep, endows them with shape and mechanical property recoverability after being subjected to severe compressive loading. Moreover, the effect of hydration is unraveled, on the material molecular structure and mechanical behavi...
Composites Science and Technology, 2016
Osteoporosis international : a journal established as result of cooperation between the European Foundation for Osteoporosis and the National Osteoporosis Foundation of the USA, Jan 18, 2015
This study was to determine if antibody against sclerostin (Scl-Ab) could prevent glucocorticoid ... more This study was to determine if antibody against sclerostin (Scl-Ab) could prevent glucocorticoid (GC)-induced osteoporosis in mice. We found that Scl-Ab prevented GC-induced reduction in bone mass and bone strength and that the anabolic effects of Scl-Ab might be partially achieved through the preservation of osteoblast activity through autophagy. Glucocorticoids (GCs) inhibit bone formation by altering osteoblast and osteocyte cell activity and lifespan. A monoclonal antibody against sclerostin, Scl-Ab, increased bone mass in both preclinical animal and clinical studies in subjects with low bone mass. The objectives of this study were to determine if treatment with the Scl-Ab could prevent loss of bone mass and strength in a mouse model of GC excess and to elucidate if Scl-Ab modulated bone cell activity through autophagy. We generated reporter mice that globally expressed dsRed fused to LC3, a protein marker for autophagosomes, and evaluated the dose-dependent effects of GCs (0, 0...
Science Advances, 2024
Controlling the balance between strength and damage tolerance in high-entropy alloys (HEAs) is ce... more Controlling the balance between strength and damage tolerance in high-entropy alloys (HEAs) is central to their application as structural materials. Materials discovery efforts for HEAs are therefore impeded by an incomplete understanding of the chemical factors governing this balance. Through first-principles calculations, this study explores factors governing intrinsic ductility of a crucial subset of HEAs-those with a body-centered cubic (bcc) crystal structure. Analyses of three sets of bcc HEAs comprising nine different compositions reveal that alloy chemistry profoundly influences screw dislocation core structure, dislocation vibrational properties, and intrinsic ductility parameters derived from unstable stacking fault and surface energies. Key features in the electronic structure are identified that correlate with these properties: the fraction of occupied bonding states and bimodality of the d-orbital density of states. The findings enhance the fundamental understanding of the origins of intrinsic ductility and establish an electronic structure-based framework for computationally accelerated materials discovery and design.
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Papers by Robert O Ritchie