Bioresorbable Composites and Implant

2021 ◽  
pp. 443-456
Author(s):  
Divya Zindani
Keyword(s):  
Mechanical Properties ◽  
Surface Modification ◽  
Degradation Rate ◽  
Clinical Applications ◽  
The Body ◽  
Metal Alloys ◽  
Medical Sciences ◽  
Intended Function ◽  
Wide Range ◽  
Modification Rate

Different biomaterials in the form of ceramics, metal alloys, composites, glasses, polymers, etc. have gained wide-range acceptance in the realm of medical sciences. Bioimplants from such biomaterials have been constructed and used widely for different clinical applications. With the continual progress, biomaterials that may be resorbed inside the body have been developed. These have done away with the major challenge of removal of an implant after it has served its intended function. Important factors are taken into consideration in design and development of implants from such biomaterials are mechanical properties, degradation rate, surface modification, rate of corrosion, biocompatibility, and non-toxicity. Given the importance of such materials in clinical applications, the chapter presents an overview of the bioresorable composites and their implants. The related properties and the functions served have been outlined briefly. Further, the challenges associated and the remedies to overcome them have also been delineated.

Bioresorbable Composites and Implant

2019 ◽  
pp. 57-76
Author(s):  
Divya Zindani
Keyword(s):  
Mechanical Properties ◽  
Surface Modification ◽  
Degradation Rate ◽  
Clinical Applications ◽  
The Body ◽  
Metal Alloys ◽  
Medical Sciences ◽  
Intended Function ◽  
Wide Range ◽  
Modification Rate

Different biomaterials in the form of ceramics, metal alloys, composites, glasses, polymers, etc. have gained wide-range acceptance in the realm of medical sciences. Bioimplants from such biomaterials have been constructed and used widely for different clinical applications. With the continual progress, biomaterials that may be resorbed inside the body have been developed. These have done away with the major challenge of removal of an implant after it has served its intended function. Important factors are taken into consideration in design and development of implants from such biomaterials are mechanical properties, degradation rate, surface modification, rate of corrosion, biocompatibility, and non-toxicity. Given the importance of such materials in clinical applications, the chapter presents an overview of the bioresorable composites and their implants. The related properties and the functions served have been outlined briefly. Further, the challenges associated and the remedies to overcome them have also been delineated.

Hydroxyapatite Coating Improves Bone Integration and Interface Strength of Polymer Implants in Bone

2008 ◽  
Vol 396-398 ◽  
pp. 331-335
Author(s):  
Joerg Brandt ◽  
M. Pfennig ◽  
Christian Bieroegel ◽  
Wolfgang Grellmann ◽  
Anke Bernstein
Keyword(s):  
Mechanical Properties ◽  
Hip Joint ◽  
Femoral Stem ◽  
The Body ◽  
Polymer Materials ◽  
Metal Alloys ◽  
Load Bearing ◽  
Natural Bone ◽  
Wide Range ◽  
Joint Prostheses

Many attempts had been made to improve the durability of artificial joint replacement and other orthopaedic implants by approaching the mechanical properties of bone and artificial material. The most joint prostheses used today are manufactured of metal alloys based on cobalt, chromium or titanium. The mechanical stiffness of these materials is much higher than that of natural bone resulting in adverse effects such as local overloading on one hand or stress shielding phenomena with the lack of adequate mechanical load on the other. Both mechanisms contribute to earl loosening and failure of implants. Polymer materials may deliver mechanical properties very similar to bone and their mechanical behaviour may be modified in a wide range during the process of manufacturing. First attempts to lower the stiffness of the implant material and to gain the stiffness range of natural bone were made in the seventies by R. Matthys with his concept of “isoelastic hip prosthesis”. In this prosthesis the femoral stem was manufactured of polyacetal, a thermoplastic polymer with very good biocompatibility and elastic properties which are much nearer to bone than common metal alloys. While the prosthesis showed good results during the mechanical testing the clinical use in vivo became a disaster. Shortly after implantation polyacetal was degraded in the body and broke down under the immense loading of the human hip joint. Later attempts to use polymer materials alone for load bearing implants also failed in clinical practice over a long time because the mechanical interlocking between bone and implant was not sufficient for the biological demand. To make the outstanding properties of polymer materials useable for load bearing implants they are backed with metal alloys (as polyethylene for hip joint cups) until the presence. Only recent developments of polymer science succeeded in the use of polymers for loaded implants. One of the most interesting materials seems to be the polyetheretherketone (PEEK) which is successfully used for spinal fusion cages [2] and computerdesigned individual implants for defect reconstruction in the skull [4] meanwhile. A pre-clinical study of a new anatomically shaped flexible acetabular cup reported satisfactory results recently [3].

scholarly journals Recent advances on the measurement and calculation of the elastic moduli of cortical and trabecular bone: A review

2011 ◽  
Vol 38 (3) ◽  
pp. 209-297 ◽  
Author(s):  
Ekaterina Novitskaya ◽  
Po-Yu Chen ◽  
Elham Hamed ◽  
Li Jun ◽  
Vlado Lubarda ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Trabecular Bone ◽  
Elastic Properties ◽  
Elastic Moduli ◽  
The Body ◽  
Multifunctional Material ◽  
Recent Advances ◽  
Wide Range ◽  
Experimental Approaches ◽  
Open Issues

In this review, recent advances on the measurement and modeling of elastic properties of cortical and trabecular bone are presented. Bone is a multifunctional material which among its other functions serves as a support for other tissues in the body. As a structural material it is stiff, strong, tough, lightweight and is adaptable. Its excellent mechanical properties are due to its complex, composite and hierarchical structure. In this paper, we outline the experimental approaches that have been used to characterize bone?s structure, composition and elastic properties at several different length scales. Then, we discuss different modeling approaches that have been employed to compute bone?s elastic moduli. We conclude by discussing the challenges and open issues in this area. Analysis of bone is of importance in orthopedics. Also, gained knowledge on bone can be used by engineers to design new bioinspired composite materials for a wide range of engineering applications.

Anatomy and mechanical properties of woods used in electric guitars

IAWA Journal ◽  
2019 ◽  
Vol 40 (1) ◽  
pp. 106-S6 ◽  
Author(s):  
Patrik Ahvenainen
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Wood Species ◽  
Principal Component ◽  
High Density ◽  
The Body ◽  
Electric Guitar ◽  
Wide Range ◽  
Acoustic Instruments ◽  
Electric Guitars

ABSTRACT Many endangered tropical hardwoods are commonly used in electric guitars. In order to find alternative woods, the current electric guitar woods need to be studied and classified as most research in this field has focused on acoustic instruments. Classification was done based on luthier literature, woods used in commercially available electric guitars, commercially available tonewoods and by interviewing Finnish luthiers. Here, the electric guitar woods are divided into three distinct classes based on how they are used in the guitar: low-density wood used in the body only (alder, poplar, basswood, ash), medium-density wood used in the body and neck (maple and mahogany), and high-density wood used in the fretboard only (rosewood and ebony). Together, these three classes span a wide range of anatomical and mechanical properties, but each class itself is limited to a relatively narrow parameter space. Statistically significant differences between these classes and the average hardwoods exist in the wood anatomy (size and organization of vessels, fibres, rays and axial parenchyma), in the mechanical properties (density, elastic modulus, Janka hardness, etc.) and in the average price per volume. In order to find substitute woods for a certain guitar wood class, density and elastic modulus can already be used to rule out most wood species. Based on principal component analysis of the elastomechanical and anatomical properties of commercially available hardwoods, few species are similar to the low- and high-density class woods. However, for all of the three electric guitar wood classes, non-endangered wood species are already commercially available from tonewood retailers that match the class characteristics presented here.

The effects of silk layer-by-layer surface modification on the mechanical and structural retention of extracellular matrix scaffolds

2020 ◽  
Vol 8 (14) ◽  
pp. 4026-4038 ◽  
Author(s):  
Xuewei Bi ◽  
Linhao Li ◽  
Zhinan Mao ◽  
Bo Liu ◽  
Lingbing Yang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Extracellular Matrix ◽  
Surface Modification ◽  
Degradation Rate ◽  
Layer By Layer ◽  
Layer Surface ◽  
Structural Retention ◽  
Tunable Mechanical Properties ◽  
Extracellular Matrix Scaffolds

The SF layer-by-layer surface functionalized SIS membrane exhibits tunable mechanical properties and degradation rate, satisfactory biocompatibility and good bioactivity.

Nature Nanocomposite Versus Man-Made Nanocomposites: Studies of Nanoscale Structural, Chemical and Mechanical Hierarchy of a Fish Scale in Contrast With Man-Made Polymer Nanocomposites

2013 ◽  
Author(s):  
D. Devaprakasam
Keyword(s):  
Mechanical Properties ◽  
Protective Layer ◽  
Living Organism ◽  
Sio2 Nanoparticles ◽  
Biological Properties ◽  
The Body ◽  
Dramatic Improvement ◽  
Fish Scale ◽  
Length Scales ◽  
Wide Range

Hierarchical designs of biological structures have remarkable physical, chemical mechanical and biological properties and functionalities over the wide range of length scales [1–4]. Man-made nanocomposites have dramatic improvement of the structural and mechanical properties but however they have very limited hierarchy [5]. Fish scales are bone-like tissues, which form a protective layer on the body of the fish and enable the fish to swim efficiently. Bones and bone-like parts in living organism are formed as tissues by self-assembly of bio-minerals and protein matrix. These tissues are bio-nanocomposites and have hierarchical structure ranging from nanoscale to macroscale [2–4]. Bio-hierarchy contains different bio-macromolecules, bio-minerals, interfacial bonds and porosity which result in gradient mechanical properties at multiple length scales [1–6]. Fish scale consists of inorganic bio-minerals and organic collagens [3,4]. Multilevel hierarchy influences elasticity, hardness and fracture toughness of fish scale. They have additional functions related to movement including reduction or increase of drag [7] and rapid manoeuvre while they are hunting or avoiding predators. In this article we report comparison studies of hierarchical nanocomposite of sardina pilchardus(sp) fish scale and man-made SiO2 nanoparticles filled nanocomposites.

Mechanical Properties and Dislocation Structure of Single Crystal Cdte Deformed in Compression at 300°C

1976 ◽  
Vol 34 ◽  
pp. 592-593
Author(s):  
Ernest L. Hall ◽  
J. B. Vander Sande
Keyword(s):  
Mechanical Properties ◽  
Single Crystal ◽  
Dislocation Structure ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Strain Curve ◽  
Optical Devices ◽  
Semiconductor Compound ◽  
Wide Range ◽  
Sample Orientation

The present paper describes research on the mechanical properties and related dislocation structure of CdTe, a II-VI semiconductor compound with a wide range of uses in electrical and optical devices. At room temperature CdTe exhibits little plasticity and at the same time relatively low strength and hardness. The mechanical behavior of CdTe was examined at elevated temperatures with the goal of understanding plastic flow in this material and eventually improving the room temperature properties. Several samples of single crystal CdTe of identical size and crystallographic orientation were deformed in compression at 300°C to various levels of total strain. A resolved shear stress vs. compressive glide strain curve (Figure la) was derived from the results of the tests and the knowledge of the sample orientation.

Creating the Wind

2020 ◽  
Vol 2 (4) ◽  
pp. 14-31
Author(s):  
Élodie Dupey García
Keyword(s):  
Indigenous Communities ◽  
The Body ◽  
Historical Sources ◽  
Natural Behavior ◽  
Sensory Experiences ◽  
Identity And Agency ◽  
Wide Range ◽  
Late Postclassic ◽  
Comparative Examination ◽  
Meteorological Phenomenon

This article explores how the Nahua of late Postclassic Mesoamerica (1200–1521 CE) created living and material embodiments of their wind god constructed on the basis of sensory experiences that shaped their conception of this divinized meteorological phenomenon. In this process, they employed chromatic and design devices, based on a wide range of natural elements, to add several layers of meaning to the human, painted, and sculpted supports dressed in the god’s insignia. Through a comparative examination of pre-Columbian visual production—especially codices and sculptures—historical sources mainly written in Nahuatl during the viceregal period, and ethnographic data on indigenous communities in modern Mexico, my analysis targets the body paint and shell jewelry of the anthropomorphic “images” of the wind god, along with the Feathered Serpent and the monkey-inspired embodiments of the deity. This study identifies the centrality of other human senses beyond sight in the conception of the wind god and the making of its earthly manifestations. Constructing these deity “images” was tantamount to creating the wind because they were intended to be visual replicas of the wind’s natural behavior. At the same time, they referred to the identity and agency of the wind god in myths and rituals.

Surface Modification and its Influence on the Microstructure and Creep Resistance of Nickel Based Superalloy René 77 / Modyfikacja Powierzchniowa Oraz Jej Wpływ Na Mikrostrukture I Wytrzymałosc Na Pełzanie Odlewów Z Nadstopu Niklu Ren´E 77

2013 ◽  
Vol 58 (1) ◽  
pp. 95-98 ◽  
Author(s):  
M. Zielinska ◽  
J. Sieniawski
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Surface Modification ◽  
Turbine Blades ◽  
Processing Parameters ◽  
Grain Structure ◽  
Creep Tests ◽  
Cobalt Aluminate ◽  
Nickel Based Superalloy ◽  
Average Grain Size

Superalloy René 77 is very wide used for turbine blades, turbine disks of aircraft engines which work up to 1050°C. These elements are generally produced by the investment casting method. Turbine blades produced by conventional precision casting methods have coarse and inhomogeneous grain structure. Such a material often does not fulfil basic requirements, which concern mechanical properties for the stuff used in aeronautical engineering. The incorporation of controlled grain size improved mechanical properties. This control of grain size in the casting operation was accomplished by the control of processing parameters such as casting temperature, mould preheating temperature, and the use of grain nucleates in the face of the mould. For nickel and cobalt based superalloys, it was found that cobalt aluminate (CoAl2O4) has the best nucleating effect. The objective of this work was to determine the influence of the inoculant’s content (cobalt aluminate) in the surface layer of the ceramic mould on the microstructure and mechanical properties at high temperature of nickel based superalloy René 77. For this purpose, the ceramic moulds were made with different concentration of cobalt aluminate in the primary slurry was from 0 to 10% mass. in zirconium flour. Stepped and cylindrical samples were casted for microstructure and mechanical examinations. The average grain size of the matrix ( phase), was determined on the stepped samples. The influence of surface modification on the grain size of up to section thickness was considered. The microstructure investigations with the use of light microscopy and scanning electron microscopy (SEM) enable to examine the influence of the surface modification on the morphology of ’ phase and carbides precipitations. Verification of the influence of CoAl2O4 on the mechanical properties of castings were investigated on the basis of results obtained form creep tests.

Structure and properties of compact articles from high-alloyed iron powder with adding of boron nitride

2020 ◽  
pp. 39-48
Author(s):  
B. O. Bolshakov ◽  
◽  
R. F. Galiakbarov ◽  
A. M. Smyslov ◽  
◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Boron Nitride ◽  
Grain Boundary ◽  
Bending Strength ◽  
Physical And Mechanical Properties ◽  
Operating Conditions ◽  
Structure And Properties ◽  
Steam Turbines ◽  
Friction Forces ◽  
Wide Range

The results of the research of structure and properties of a composite compact from 13 Cr – 2 Мо and BN powders depending on the concentration of boron nitride are provided. It is shown that adding boron nitride in an amount of more than 2% by weight of the charge mixture leads to the formation of extended grain boundary porosity and finely dispersed BN layers in the structure, which provides a high level of wearing properties of the material. The effect of boron nitride concentration on physical and mechanical properties is determined. It was found that the introduction of a small amount of BN (up to 2 % by weight) into the compacts leads to an increase in plasticity, bending strength, and toughness by reducing the friction forces between the metal powder particles during pressing and a more complete grain boundary diffusion process during sintering. The formation of a regulated structure-phase composition of powder compacts of 13 Cr – 2 Mо – BN when the content of boron nitride changes in them allows us to provide the specified physical and mechanical properties in a wide range. The obtained results of studies of the physical and mechanical characteristics of the developed material allow us to reasonably choose the necessary composition of the powder compact for sealing structures of the flow part of steam turbines, depending on their operating conditions.

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