A facile synthesis method and fracture toughness evaluation of catfish bones-derived hydroxyapatite

MRS Advances ◽  
2020 ◽  
Vol 5 (26) ◽  
pp. 1357-1366
Author(s):  
E.S Akpan ◽  
M. Dauda ◽  
L.S Kuburi ◽  
D.O Obada

AbstractIn this study, biological hydroxyapatite (HAp) was synthesized from catfish (Pangasius hypophthalmus) bones. First, the as-received catfish bones were de-proteinized in open air, and then converted to HAp by a solid state heat treatment method at a temperature of 900 °C for a holding time of 2 h in a muffle furnace. X-ray diffraction (XRD) analysis confirmed that HAp with high crystallinity of 99.9% was formed matching the structural properties of flouro-apatite with crystallite sizes of approximately 37.1 nm. The morphology of the HAp prepared showed irregularly shaped particles and revealed the appearance of open pores with a less agglomerated structure and a Ca/P ratio of about 1.58. The specific mechanical properties: hardness, compressive strength and fracture toughness of the catfish derived scaffolds were recorded as 480 MPa, 1.92 MPa, and 5.72 Mpa.m1/2, respectively. The fracture toughness of the HAp derived scaffolds suggests that the produced biomaterial is promising for biomedical applications. These findings are useful for the production and application of the HAp powders prepared from catfish bones, and further suggests a possible low-cost route for producing inexpensive ceramics using natural catfish bones.

Author(s):  
Kunio Onizawa ◽  
Katsuyuki Shibata ◽  
Masahide Suzuki ◽  
Daisuke Kato ◽  
Yinsheng Li

Using the probabilistic fracture mechanics analysis code PASCAL, we studied the treatment method of an embedded crack and the fracture toughness evaluation methods on the probability of crack initiation and fracture of a reactor pressure vessel (RPV). For calculating the stress intensity factor (SIF) of an embedded crack, the ASME and CRIEPI procedures were introduced into the PASCAL code. The CRIEPI method enables us to calculate the SIF values at three points on the crack tip. Under a severe pressurized thermal shock (PTS) condition, the crack growth analysis methods with different SIF calculation points and crack growth directions are compared. To evaluate precisely the fracture toughness after neutron irradiation, the new fracture toughness curves based on the Weibull distribution were incorporated into the PASCAL code. The calculated results with these new curves showed little difference in the conditional probabilities of RPV fracture as compared to the curve currently used in the U.S.


2011 ◽  
Vol 186 ◽  
pp. 7-10 ◽  
Author(s):  
Gui Yang Liu ◽  
Jun Ming Guo ◽  
Bao Sen Wang ◽  
Ying He

Single phase Al3+ doped LiMn2O4 has been prepared by flameless solution combustion synthesis method at 600oC for 1h. X-ray diffraction (XRD) and scanning electric microscope (SEM) were used to determine the phase composition and micro morphology of the products. XRD analysis indicates that the purities increase and the lattice parameters of the products decrease with increasing Al3+ content. Electrochemical test indicates that the cycling performance of the products with Al3+ doping are better than that of the product without Al3+ doping. The product LiAl0.10Mn1.90O4 gets the best electrochemical performance. At the current density of 30mA/g, the initial discharge capacity of LiAl0.10Mn1.90O4 is 124.8mAh/g, and after 20 cycles, the capacity retention is more than 89%. SEM investigation indicates that the particles of LiAl0.10Mn1.90O4 are sub-micron in size and well dispersed.


2021 ◽  
Vol 1028 ◽  
pp. 62-67
Author(s):  
Yuyu R. Tayubi ◽  
Yati Maryati ◽  
Muhammad Abdan Syakuur ◽  
Diba G Auliya ◽  
Togar Saragi ◽  
...  

The samples of Eu2-xCexCuO4 (ECCO) with x = 0.10, 0.13, 0.17 and 0.20 have been synthesized by the solid reaction method without annealing process [1,2]. Each sample is covered by CuO powder to prevent excess oxygen entering the sample during heating process. The purpose of this research is to study the crystal structure and the level of phase purity in ECCO samples in the wide ranges of doping concentration of ECCO. The results of X-ray diffraction (XRD) characterization showed that the main peaks of T' tetragonal structure were observed in all samples. From the XRD analysis, it was found that the level of phase purity of ECCO was 100 % for x = 0.10, 100 % for x = 0.13, 79.5.% for x = 0.17, and 79.1 % for x = 0.20, respectively. For the lattice constant, it is found that both a and c-axis did not change significantly as the concentration increased. These results show that the synthesis method with CuO covering has succeeded in synthesizing materials with high phase purity although the constants do not change significantly when the concentration increased. However, there are some impurity phases found in high concentration of x that is probably due to the existence of excess oxygen, which was not fully absorbed by CuO Covering.


Sign in / Sign up

Export Citation Format

Share Document