Weibull analysis of ceramics and related materials: A review.

It has been realized throughout the years that an ideal combination of high toughness, hardness and strength is required in many engineering applications that need load-bearing capabilities. Ceramics and related materials have significant constraints for structural and particular non-structural applications due to their low toughness and limited strength while having substantially superior hardness than typical metallic materials. For example, hydroxyapatite (HAp) has gained attention for applications in orthopaedic implants, dental materials, drug delivery, etc. Researchers have continued to strive to produce HAp materials with reliable properties within the acceptable Weibull modulus (m) for load bearing. The Weibull analysis (WA) is a statistical analysis adopted widely in reliability applications to detect failure periods. Researchers have confirmed it to be an effective technique to get results on the reliability of materials at a moderately low rate with assured reliability of the material or component. This review summarizes the WA and the steps in the Weibull method for its reliability analysis to predict the failure rate of ceramics like HAp and other related materials. Also, the applications of WA for these materials were reviewed. From the review, it was discovered that Weibull distribution is proven to confer to the feeblest-link concept. For brittle materials, it was revealed that the Weibull Modulus ranges from 2 to 40, and environment, production processes, and comparative factors are well-thought-out contributing factors for reliability. In addition, the confidence interval can be up to 95 %. The frequently used technique for reliability valuation is to syndicate the Weibull statistics. Also, a very narrow distribution is desirable to offer the expected likelihood. Furthermore, when paired with trials, Monte Carlo simulations prove to be a very helpful tool for forecasting the dependability of different estimate techniques and their optimization. Finally, if the equivalent m is anticipated to be high, it signifies that the material has a high degree of homogeneity of properties and high reliability. WA can find application in predicting the dependability and lifetime of materials, making it widely utilized in engineering and other disciplines. It is especially useful for analysing data in which the likelihood of failure per unit of time varies over time.

Hydroxyapatite nano-pillars on TI-6Al-4V: Enhancements in cell spreading and proliferation during cell/surface integration.

Despite the attractive combinations of cell/surface interactions, biocompatibility, and good mechanical properties of Ti-6Al-4V, there is still a need to enhance the early stages of cell/surface integration that are associated with the implantation of biomedical devices into the human body. This paper presents a novel, easy and reproducible method of nanoscale and nanostructured hydroxyapatite (HA) coatings on Ti-6Al-4V. The resulting nanoscale coatings/nanostructures are characterized using a combination of Raman spectroscopy, scanning electron microscopy equipped with energy dispersive x-ray spectroscopy. The nanostructured/nanoscale coatings are shown to enhance the early stages of cell spreading and integration of bone cells (hFOB cells) on Ti-6Al-4V surfaces. The improvements include the acceleration of extra-cellular matrix, cell spreading and proliferation by nanoscale HA structures on the coated surfaces. The implications of the results are discussed for the development of HA nanostructures for the improved osseointegration of Ti-6Al-4V in orthopedic and dental applications.

A pedagogical approach for the development and optimization of a novel mix of biowastes-derived hydroxyapatite using the Box-Behnken experimental design.

The current study details the creation of synthetic hydroxyapatite (HAp) using a combination of catfish and bovine bones (C&B). This is done to design the optimum processing parameters and consolidate instructional strategies to develop HAp scaffolds for biomedical engineering. The HAp produced from the novel mix of the biogenic materials (C&B) was through calcination and supported with the sol-gel technique, sintering, and low-cold compaction pressure. The ideal preparation conditions were identified with the aid of the Box-Behnken statistical design in response surface methodology. To understand the physicochemical and mechanical properties of the formulation, analytical studies on the synthesized HAp were carried out. To establish a substantial relation between the physicomechanical properties of the produced HAp scaffolds, three parameters- sintering temperature, compaction loads, and holding times were used. In the evaluation, the sintering temperature was found to have the greatest impact on the material's physicomechanical properties, with compressive strength (13 MPa), porosity (49.45 %), and elastic modulus (2.216 GPa) being the most enhanced properties in that order. The physicomechanical characteristics of the HAp scaffolds were at their optimal at 900 °C, 1 h 18 min of holding time, and 311.73 Pa of compaction pressure. X-ray diffraction (XRD) and Fourier transform infrared (FTIR) results showed that powders with a dominant HAp phase were produced at all runs, including the optimum run. Therefore, using a computationally effective methodology that is helpful for novelties in biomedical engineering education, this study demonstrates the optimal process for the synthesis of a novel matrix bone-derived HAp, showing the most significant relations liable for manufacturing medically suitable HAp scaffolds from the mixture of bovine and catfish bones.

Self-organized mycelium biocomposites: Effects of geometry and laterite composition on compressive behavior.

This study investigates the compressive deformation and the effect of structural architecture on the compressive strength of bioprocessed mycelium biocomposites reinforced with laterite particles. In the mycelium blocks, lignocellulosic hemp hurds function as reinforcing and nutritional substrates. The mycelium acts as a supportive matrix, binding the hemp hurds and the laterite particles which are integrated for further reinforcement to improve the compressive strength of the composite. The compressive behavior of the composites is elucidated using a combined approach of experimental and theoretical studies. The deformation mechanisms are investigated via in-situ observations of the specimens under uniaxial compressive loading. The experiments show that the compressive deformation results in progressive micro-buckling in slender specimens, whereas thicker samples exhibit a soft elastic response at small strain levels followed by continuous stiffening at larger strains. Based on the experimental observations and the morphological characterization, a column buckling analysis was developed for the mycelium-hemp composites to further explain the observed deformation phenomena.