Search results for "Wear"
showing 10 items of 275 documents
Influence of friction stir processing conditions on the manufacturing of Al-Mg-Zn-Cu alloy/boron carbide surface composite
2018
Abstract Surface metal matrix composites were synthesized via friction stir processing (FSP) on the surface of aluminium alloy 7075 (AA 7075) sheets by incorporating B4C particles (B4CP). The influence of tool rotational speeds, powder particle sizes, and change in tool travel direction between FSP passes on particle distribution and resulting properties were studied in detail. Change in tool travel direction, decreased tool rotation speed and fine B4C particles enhanced B4CP distribution and wear properties thereof. Wear resistance of composites were doubled on account of the B4CP distribution and resultant several strengthening mechanisms.
Repeated exposure of acidic beverages on esthetic restorative materials: An in-vitro surface microhardness study.
2015
Background A manifold increase in the consumption of aerated beverages has witnessed a twin increase in tooth wear and raised demand for esthetic restorative materials. This study aimed to evaluate the surface microhardness changes of esthetic restorative materials following treatment with aerated beverages in an in-vitro situation. Material and Methods The initial surface microhardness of the restorative materials GC Fuji II LC, GC Fuji IX, Nano Glass ionomer, Resin and Nano composite was recorded. These materials were studied under 3 groups that included those exposed to the acidic beverages daily, weekly once in a month and those that had no exposures at all. The final surface microhardn…
Let the machine do the work: learning to reduce the energetic cost of walking on a split‐belt treadmill
2019
In everyday tasks such as walking and running, we often exploit the work performed by external sources to reduce effort. Recent research has focused on designing assistive devices capable of performing mechanical work to reduce the work performed by muscles and improve walking function. The success of these devices relies on the user learning to take advantage of this external assistance. Although adaptation is central to this process, the study of adaptation is often done using approaches that seem to have little in common with the use of external assistance. We show in 16 young, healthy participants that a common approach for studying adaptation, split-belt treadmill walking, can be under…
Effect of in situ aspartame mouthwash to prevent intrinsic and extrinsic erosive tooth wear
2020
Background The aim was to evaluate whether aspartame regular mouthwash prior to erosive challenges with citric or hydrochloric acids would be able to prevent erosive enamel wear. Material and methods This randomized, single blind in situ study was conducted with 3 crossover phases of 5 days. Polished bovine enamel blocks (n=252) were randomly divided among 6 groups/ 3 phases/ 21 volunteers. The groups under study were: aspartame solution (0.024% of aspartame in deionized water - experimental group), deionized water (negative-control) and stannous-containing solution (Elmex® Erosion Protection Dental Rinse; positive-control); subjected to erosion on citric acid or hydrochloric acid. Four tim…
Dental pulp calcifications in prehistoric and historical skeletal remains
2020
Abstract Background The prevalence of hard tissue formations in the dental pulp varies considerably. Beside ageing processes and irritations of the dental pulp, etiological associations with cardiovascular disease and dietary habits have been discussed, which are of particular research interest. The aim of this pilot study is to provide new insights on structural and etiological factors involved in the development of pulp calcifications by investigating skeletal remains from different (pre)historic periods. Methods The jaws of 46 skeletons excavated in central Germany, were examined for the presence of pulp stones using digital volume tomography (DVT). A total of 1122 teeth were examined wi…
Computational modeling of bicuspid aortopathy: Towards personalized risk strategies.
2019
This paper describes current advances on the application of in-silico for the understanding of bicuspid aortopathy and future perspectives of this technology on routine clinical care. This includes the impact that artificial intelligence can provide to develop computer-based clinical decision support system and that wearable sensors can offer to remotely monitor high-risk bicuspid aortic valve (BAV) patients. First, we discussed the benefit of computational modeling by providing tangible examples of in-silico software products based on computational fluid-dynamic (CFD) and finite-element method (FEM) that are currently transforming the way we diagnose and treat cardiovascular diseases. Then…
Microwear and isotopic analyses on cave bear remains from Toll Cave reveal both short-term and long-term dietary habits
2019
Dietary habits of the extinct Ursus spelaeus have always been a controversial topic in paleontological studies. In this work, we investigate carbon and nitrogen values in the bone collagen and dental microwear of U. spelaeus specimens recovered in Level 4 from Toll Cave (Moia, Catalonia, NE Iberian Peninsula). These remains have been dated to > 49,000 C-14 BP. The ability of both proxies to provide data on the diet of U. spelaeus at different times in the life-history (isotopes: average diet of life; microwear: last days/weeks before death), allows us to generate high-resolution and complementary data. Our results show lower values (delta C-13 & delta N-15) in cave bears than in strict herb…
Microwear textures associated with experimental near-natural diets suggest that seeds and hard insect body parts cause high enamel surface complexity…
2022
In mammals, complex dental microwear textures (DMT) representing differently sized and shaped enamel lesions overlaying each other have traditionally been associated with the seeds and kernels in frugivorous diets, as well as with sclerotized insect cuticles. Recently, this notion has been challenged by field observations as well as in vitro experimental data. It remains unclear to what extent each food item contributes to the complexity level and is reflected by the surface texture of the respective tooth position along the molar tooth row. To clarify the potential of seeds and other abrasive dietary items to cause complex microwear textures, we conducted a controlled feeding experiment wi…
Corrosion and wear resistance of coatings produced on AZ31 Mg alloy by plasma electrolytic oxidation in silicate-based K2TiF6 containing solution: Ef…
2022
Abstract In this research, plasma electrolytic oxidation coatings were prepared on AZ31 Mg alloy in a silicate-based solution containing K2TiF6 using bipolar and soft sparking waveforms with 10, 20, and 30% cathodic duty cycles. The coatings displayed a net-like surface morphology consisted of irregular micro-pores, micro-cracks, fused oxide particles, and a sintered structure. Due to the incorporation of TiO2 colloidal particles and the cathodic pulse repair effect, most of the micro-pores were sealed. Long-term corrosion performance of the coatings was investigated using electrochemical impedance spectroscopy during immersion in 3.5 wt.% NaCl solution up to 14 days. The coating grown by t…
Post-mortem alteration of diet-related enamel surface textures through artificial biostratinomy: A tumbling experiment using mammal teeth
2019
In the fossil record, teeth are often all that remains of a fossil organism. Dental microwear texture analysis (DMTA) is a common proxy for diet using dental wear features at the μm-scale, enabling comparative and quantitative assessments of various feeding traits in extant and extinct species. In extinct species, original diet-related dental wear features may be overprinted by post-mortem alteration including fluvial transport. Here we experimentally investigate the effects of mechanical alteration on diet-related 3D enamel surface texture (3DST) patterns of different mammal teeth. Post canine teeth of Equus sp., Capreolus capreolus and Otomys sp. are tumbled in sediment-water suspensio…