Time-lapse micro-CT analysis of fatigue microcrack propagation in cortical bone

2020 ◽  
Vol 15 (03) ◽  
pp. C03031-C03031 ◽  
Author(s):  
T. Fíla ◽  
P. Koudelka ◽  
I. Kumpová ◽  
M. Vopálenský ◽  
J. Šleichrt ◽  
...  
2007 ◽  
Vol 80 (3) ◽  
pp. 211-219 ◽  
Author(s):  
David Cooper ◽  
Andrei Turinsky ◽  
Christoph Sensen ◽  
Benedikt Hallgrimsson

Author(s):  
Mustafa Ozcan ◽  
Fariz Salimov ◽  
Andy Temmerman ◽  
Onur Ucak Turer ◽  
Bahar Alkaya ◽  
...  

The aim of this study was to measure the effect of drilling speed on heat generation in the cortical bone, on primary and secondary implant stability of implants and on early and late bone healing with micro-computed tomography (micro-CT). Sixty implants were placed in the iliac crest of six sheep in order to form 5 different drilling protocols: 50rpm without saline cooling, and 400rpm, 800rpm, 1200rpm and 2000rpm with saline cooling.  Simultaneous cortical bone temperature and primary stability at the time of placement; secondary stability and the ratio between relative bone and tissue volume (BV/TV) in 2D and 3D in micro-CT analysis were evaluated after 4 and 8 weeks. The 50rpm group had the highest cortical bone temperature and the longest operation duration with the highest primary stability. Slightly higher values of secondary stability (T2) and subsequent 2D and 3D BV/TV values were found in 1200 rpm with irrigation at 8 weeks. All groups had sufficient ISQ values at 8 weeks for loading although the micro-CT analysis showed varying percentages of bone tissue around implants. The influence of drill speed for implant osteotomy and its irrigation is minimal when it comes to changes in temperature of the cortical bone, primary and secondary implant stability and BV/TV.


Author(s):  
Melissa R. Requist ◽  
Yantarat Sripanich ◽  
Tim Rolvien ◽  
Amy L. Lenz ◽  
Alexej Barg

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1995
Author(s):  
Mirko Sinico ◽  
Suraj Dinkar Jadhav ◽  
Ann Witvrouw ◽  
Kim Vanmeensel ◽  
Wim Dewulf

Recently, the use of novel CuCr1 surface-modified powder for reliable laser powder-bed fusion (LPBF) manufacturing has been proposed, enabling a broader LPBF processing window and longer powder storage life. Nevertheless, virgin CuCr1 powder is also LPBF processable, on the condition that a high-energy density is employed. In this work, we compare two dense specimens produced from virgin and surface-modified CuCr1 powder. Furthermore, a third sample fabricated from surface-modified powder is characterized to understand an abnormal porosity content initially detected through Archimedes testing. Utilizing high-resolution micro-CT scans, the nature of the defects present in the different samples is revealed. Pores are analyzed in terms of size, morphology and spatial distribution. The micro-CT data reveal that the virgin CuCr1 dense specimen displays keyhole pores plus pit cavities spanning multiple layer thicknesses. On the other hand, the sample fabricated with the surface-modified CuCr1 powder mainly contains small and spherical equi-distributed metallurgical defects. Finally, the CT analysis of the third specimen reveals the presence of a W contamination, favoring lack-of-fusion pores between subsequent LPBF layers. The LPBF melting mode (keyhole or conductive), the properties of the material, and the potential presence of contaminants are connected to the different porosity types and discussed.


Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 408
Author(s):  
Anna Stepien

This paper describes the use of glass sand in the production of autoclaved bricks. Traditional autoclaved materials consist of SiO2, CaO, and H2O. The purpose of the tests is to analyze the possibility of using glass sand in autoclaved materials and to determine their properties and durability. Depending on the structure, building materials can have porosities ranging from 0% (glass, metals) to over 90% (thermal insulation materials such as aerated concrete). Porosity of materials is directly related to the strength of materials and their density, and further to the thermal and acoustic insulation properties of products used especially for external wall construction, i.e., bricks, concrete, and aerated concrete. This type of silicate brick is formed at a temperature of 203 °C, therefore the dominant phase forming the microstructure is tobermorite, in contrast to the C-S-H phase, which dominates in concretes and which is characterized by a larger specific surface. The nature of pores, their number, appearance and arrangement in the material can be studied using computer techniques (SEM, XRD, computed tomography, porosimetry). Computed tomography (micro-CT analysis) showed that the number of voids in the material modified by glass sand is about 20% in relation to the weight of the product. The density of the product with glass sand was determined to be 2.2 kg/dm3.


2018 ◽  
Vol 221 (4) ◽  
pp. 1831-1842 ◽  
Author(s):  
Adriano Losso ◽  
Andreas Bär ◽  
Birgit Dämon ◽  
Christian Dullin ◽  
Andrea Ganthaler ◽  
...  

2019 ◽  
Vol 31 (1) ◽  
pp. 29-36 ◽  
Author(s):  
Ken Nakahara ◽  
Maiko Haga‐Tsujimura ◽  
Kensuke Igarashi ◽  
Eizaburo Kobayashi ◽  
Benoit Schaller ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document