Mechanical Properties of Hydroxyapatite Doped with Magnesium, Used in Bone Implants

2013 ◽  
Vol 430 ◽  
pp. 222-229 ◽  
Author(s):  
Oana Suciu ◽  
Teodora Ioanovici ◽  
Liviu Bereteu
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Modulus Of Elasticity ◽  
Mechanical Characteristics ◽  
Precipitation Method ◽  
Bone Implants ◽  
Wet Precipitation ◽  
Longitudinal Modulus

Hydroxyapatite is a biomaterial, more exactly a bioceramic, from a category of materials frequently used in bone implants. In order to improve mechanical properties, hydroxyapatite is doped with different chemical substitutes, among which the most used are: Mg2*, Zn 2*, La3*, Y3*, In3* Bi3* CO32-, Si and Mn. In the paper are presented the modality of obtaining hydroxyapatite doped with magnesium through wet precipitation method and also the determination of its main mechanical characteristics. There is also an analysis on the effects of magnesium on the following mechanical properties: density, hardness, longitudinal modulus of elasticity, conductibility and thermal stability.

scholarly journals Classification-Based Regression Models for Prediction of the Mechanical Properties of Roller-Compacted Concrete Pavement

2020 ◽  
Vol 10 (11) ◽  
pp. 3707 ◽  
Author(s):  
Ali Ashrafian ◽  
Mohammad Javad Taheri Amiri ◽  
Parisa Masoumi ◽  
Mahsa Asadi-shiadeh ◽  
Mojtaba Yaghoubi-chenari ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Regression Models ◽  
Mechanical Characteristics ◽  
Concrete Pavement ◽  
Supplementary Cementitious Materials ◽  
Fine Aggregate ◽  
Roller Compacted Concrete ◽  
Interaction Detection ◽  
Model Tree

In the field of pavement engineering, the determination of the mechanical characteristics is one of the essential processes for reliable material design and highway sustainability. Early determination of the mechanical characteristics of pavement is essential for road and highway construction and maintenance. Tensile strength (TS), compressive strength (CS), and flexural strength (FS) of roller-compacted concrete pavement (RCCP) are crucial characteristics. In this research, the classification-based regression models random forest (RF), M5rule model tree (M5rule), M5prime model tree (M5p), and chi-square automatic interaction detection (CHAID) are used for simulation of the mechanical characteristics of RCCP. A comprehensive and reliable dataset comprising 621, 326, and 290 data records for CS, TS, and FS experimental cases was extracted from several open sources in the literature. The mechanical properties are determined based on influential input combinations that are processed using principle component analysis (PCA). The PCA method specifies that volumetric/weighted content forms of experimental variables (e.g., coarse aggregate, fine aggregate, supplementary cementitious materials, water, and binder) and specimens’ age are the most effective inputs to generate better performance. Several statistical metrics were used to evaluate the proposed classification-based regression models. The RF model revealed an optimistic classification capacity of the CS, TS, and FS prediction of the RCCP in comparison with the CHAID, M5rule, and M5p models. Monte-Carlo simulation was used to verify the results in terms of the uncertainty and sensitivity of variables. Overall, the proposed methodology formed a reliable soft computing model that can be implemented for material engineering, construction, and design.

scholarly journals Polyimide-Based Nanocomposites with Binary CeO2/Nanocarbon Fillers: Conjointly Enhanced Thermal and Mechanical Properties

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1952
Author(s):  
Alexandra L. Nikolaeva ◽  
Iosif V. Gofman ◽  
Alexander V. Yakimansky ◽  
Elena M. Ivan’kova ◽  
Ivan V. Abalov ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Carbon Nanoparticles ◽  
Mechanical Characteristics ◽  
Functional Performance ◽  
Polymer Materials ◽  
Thermal And Mechanical Properties ◽  
Binary Blends ◽  
Working Temperature ◽  
The Matrix

To design novel polymer materials with optimal properties relevant to industrial usage, it would seem logical to modify polymers with reportedly good functionality, such as polyimides (PIs). We have created a set of PI-based nanocomposites containing binary blends of CeO2 with carbon nanoparticles (nanocones/discs or nanofibres), to improve a number of functional characteristics of the PIs. The prime novelty of this study is in a search for a synergistic effect amidst the nanofiller moieties regarding the thermal and the mechanical properties of PIs. In this paper, we report on the structure, thermal, and mechanical characteristics of the PI-based nanocomposites with binary fillers. We have found that, with a certain composition, the functional performance of a material can be substantially improved. For example, a PI containing SO2-groups in its macrochains not only had its thermal stability enhanced (by ~20 °C, 10% weight loss up to 533 °C) but also had its stiffness increased by more than 10% (Young’s modulus as high as 2.9–3.0 GPa) in comparison with the matrix PI. In the case of a PI with no sulfonic groups, binary fillers increased stiffness of the polymer above its glass transition temperature, thereby widening its working temperature range. The mechanisms of these phenomena are discussed. Thus, this study could contribute to the design of new composite materials with controllable and improved functionality.

scholarly journals Comparative Study on Micromechanical Properties of ZnO:Ga and ZnO:In Luminiscent Ceramics

2021 ◽  
Vol 58 (1) ◽  
pp. 23-32
Author(s):  
F. Muktepavela ◽  
A. Zolotarjovs ◽  
R. Zabels ◽  
K. Kundzins ◽  
E. Gorokhova ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Modulus Of Elasticity ◽  
Mechanical Characteristics ◽  
X Ray ◽  
Micromechanical Properties ◽  
Doped Zno ◽  
Hardness Values ◽  
Zno Ceramics ◽  
Scanning Electron

Abstract Indium (0.038 at.%) and gallium (0.042 at.%) doped ZnO ceramics were prepared by hot pressing. Ceramics were investigated to determine their structural and mechanical characteristics for the prospective use in scintillators. Based on results of nanoindentation, atom force and scanning electron microscopy as well as energy dispersive X-ray spectra measurements, locations of gallium within grain, indium at grain boundaries (GBs) and their different effect on the mechanical properties of ZnO ceramics were detected. Doping of gallium led to the increased modulus of elasticity in grain, decreased hardness near GBs, stabilization of micropores and brittle intercrystalline fracture mode. ZnO:In ceramic has modulus of elasticity and hardness values close to ZnO characteristics, the increased fracture toughness and some plasticity near GBs. Differences in the micromechanical properties of the ceramics correlate with the location of dopants. Results demonstrate that the ZnO:In ceramic has a greater stress relaxation potential than the ZnO:Ga.

scholarly journals Properties of Biocomposites Produced with Thermoplastic Starch and Digestate: Physicochemical and Mechanical Characteristics

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6092
Author(s):  
Adam Ekielski ◽  
Tomasz Żelaziński ◽  
Pawan Kumar Mishra ◽  
Jacek Skudlarski
Keyword(s):  
Mechanical Properties ◽  
Mechanical Characteristics ◽  
Moisture Absorption ◽  
Thermoplastic Starch ◽  
Colour Difference ◽  
Strength Parameters ◽  
Basic Parameters ◽  
Superior Mechanical Properties ◽  
Advantageous Effect

This paper presents the results of a study on the influence of the addition of digestate (DG) sludge from an agricultural biogas plant on the mechanical properties of the coating obtained from thermoplastic starch (TPS). The dried, fragmented digestate, some of which had previously undergone ultrasound treatment, is used in the study. Biocomposites are produced by the pouring method using Teflon moulds as matrices. The physicomechanical study included the determination of the basic parameters of the materials obtained. Strength parameters, the contact angle, thermogravimetric properties (TGA), colour and colour difference and moisture absorption are determined. Photographs of the surface of the samples are taken with a scanning electron microscope (SEM) as well. It is found that the addition of the digestate has an advantageous effect on improving the physical and mechanical parameters. In general, samples with digestate also have a higher strength compared to the pure TPS material. The highest tensile strength and Young’s modulus are found in samples with the 14 wt.% addition of ultrasound-treated digestate. On the basis of this study, it can be concluded that the addition of digestate is a promising approach for the production of TPS biocomposites with superior mechanical properties.

scholarly journals Determination of the longitudinal modulus of elasticity in structural sawn wooden beams by the least squares method

2012 ◽  
Vol 14 (2) ◽  
pp. 61-70 ◽  
Author(s):  
André Luis Christoforo ◽  
Sérgio Luiz Moni Ribeiro Filho ◽  
Anderson Renato Vobornik Wolensky ◽  
Anelize Borges Monteiro ◽  
Francisco Antonio Rocco Lahr ◽  
...  
Keyword(s):  
Least Squares ◽  
Modulus Of Elasticity ◽  
Least Squares Method ◽  
Longitudinal Modulus

scholarly journals THERMOPHYSICAL AND PHYSICO-MECHANICAL CHARACTERISTICS OF EPOXYURETHANE COMPOSITES

2020 ◽  
Vol 86 (8) ◽  
pp. 134-143
Author(s):  
Larisa Yashenko
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Sodium Silicate ◽  
Modulus Of Elasticity ◽  
Relative Deformation ◽  
Scanning Calorimetry ◽  
Physicomechanical Characteristics ◽  
Relative Compression ◽  
Inorganic Constituents ◽  
The Eu

Epoxy urethane composites (EU) have been developed based on polyisocyanate (PIC), epoxy resin (ED-20), and sodium silicate (SS). The results of the study of the influence of the ratio of the components of the EU on their thermophysical and physicomechanical characteristics are presented. The method ofdifferential scanning calorimetry revealed thatthese systems do not have clear temperature transitions, which indicates a fairly homogeneous and rigid structure. Studies of thermal properties by the method of dynamic thermogravimetry have shown that as the amount of sodium silicate increases, the temperature of the onset of decomposition of the EU is shifted by 20 ° C towards lower temperatures. At the same time, there is a slowdown in the decomposition of epoxy urethanes (weight loss is 12-14%), due to the presence of heterocyclic isocyanurate fragments, which is inherent in its own high thermal stability. The mechanical properties of the EU, such as compressive strength, modulus of elasticity, relative compression deformation, flexural strength, and water absorption, are determined depending on the ratio of components. High mechanical properties are shown regardless of the inorganic component amount. The modulus of elasticity, strength, and relative deformation in compression is in the range of 1916.4 - 4187.6 MPa, 117.4 - 133.1 MPa, and 24.7-30.4%, respectively. The highest flexural strengths are characterized by the EC composition of the PIC / SS / ED-20 = 80/20/20, and the lowest - the EC composition of the PIC / SS / ED-20 = 70/30/20. The results of the studies show that, by changing the ratio of organic and inorganic constituents in the EC, it is possible to regulate the thermal stability and physicomechanical properties of epoxy urethane composites depending on their purpose.

scholarly journals The distribution regularities of structural, physical and mechanical characteristics of the fillings of shredded wood in the bunkers at the gravity movement

2016 ◽  
Vol 6 (3) ◽  
pp. 100-108
Author(s):  
Лозовецкий ◽  
Vyacheslav Lozovetskiy ◽  
Шадрин ◽  
Anatoliy Shadrin ◽  
Лебедев ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Characteristics ◽  
Structural Characteristics ◽  
External Friction ◽  
Experimental Setup ◽  
Analytical Studies ◽  
Physical And Mechanical Characteristics

Described the experimental setup and presents the results of theoretical and experimental analytical studies of structural characteristics (coefficient of fully wood - porosity or the porosity) and physico-mechanical properties (coefficients of internal and external friction) of the materials crushed wood, a generalization which allowed us to obtain the calculated dependences for determination of their size by volume of bunkers axisymmetric geometry.

scholarly journals Classification-Based Regression Models for Prediction of Mechanical Properties of Roller Compacted Concrete Pavement

2020 ◽  
Author(s):  
Ali Ashrafian ◽  
Mohammad Javad Taheri Amiri ◽  
Mahsa Asadi-shiadeh ◽  
Isa Yaghoobi-chenari ◽  
Amir Mosavi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Regression Models ◽  
Mechanical Characteristics ◽  
Concrete Pavement ◽  
Supplementary Cementitious Materials ◽  
Fine Aggregate ◽  
Roller Compacted Concrete ◽  
Interaction Detection ◽  
Model Tree

In the field of pavement engineering, the determination of the mechanical characteristics is one of the essential process for reliable material design and highway sustainability. Early determination of mechanical characteristics of pavement is highly essential for road and highway construction and maintenance. Tensile strength (TS), compressive strength (CS) and flexural strength (FS) of roller compacted concrete pavement (RCCP) are very crucial characteristics as they are necessitated for many data from mixture proportions as input variables. In this research, the classification-based regression models named Random Forest (RF), M5rule model tree (M5rule), M5prime model tree (M5p) and Chi-square Automatic Interaction Detection (CHAID) are developed for simulation of the mechanical characteristics of RCCP. A comprehensive and reliable dataset comprising 621, 326 and 290 data records for CS, TS and FS experimental cases extracted from several open sources over the literature. The mechanical properties are developed based on influential inputs combination that processed using Principle Component Analysis (PCA). The applied PCA method as feature selection is specified that volumetric/weighted content forms of experimental variables (e.g., coarse aggregate, fine aggregate, supplementary cementitious materials, water and binder) and specimens’ age are the most effective inputs to generate the better performances. Several statistical metrics are measured to evaluate proposed classification-based regression models. RF model revealed an optimistic classification capacity of the CS, TS and FS prediction of the RCCP in comparison with the CHAID, M5rule, and M5p models. The research is extended for the results verification using Monte-carlo model for the uncertainty and sensitivity of variables importance analysis. Overall, the proposed methodology indicated a reliable soft computing model that can be implemented for the material engineering construction and design.

The Effect of Porosity Type on the Mechanical Performance of Porous NiTi Bone Implants

2016 ◽  
Author(s):  
Amirhesam Amerinatanzi ◽  
Narges Shayesteh Moghaddam ◽  
Hamdy Ibrahim ◽  
Mohammad Elahinia
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Shape Memory ◽  
Modulus Of Elasticity ◽  
Geometrical Structure ◽  
Niti Alloy ◽  
Porous Structures ◽  
Bone Implants ◽  
Equivalent Modulus ◽  
Diamond Type

NiTi has been shown to be of great interest for bone implant applications. Introducing porosity to NiTi bone implants is an effective technique to tune their equivalent modulus of elasticity in order to acquire similar value to that of cortical bone. Moreover, such porous implants allow for better tissue ingrowth due to the interconnecting open pore structure. The effect of porosity percentage on the NiTi equivalent modulus of elasticity is well understood. However, the effect of porosity type on NiTi bone implant’s performance, in terms of the geometrical structure and other mechanical properties, has not yet been investigated. To this end, we simulated three porous structures made of shape memory Ti-rich Ni50.09Ti alloy. The effect of porosity type on the NiTi implant’s geometrical structure and mechanical properties was studied using numerical tests. The purpose is to compare three NiTi implants with different kinds of porosities, at a similar level of porosity (i.e., 69 %). The assigned porosity types in this study are Schwartz-type, Gyroid-type, and Diamond-type. Three triply periodic minimal surface (TPMS) models (9mm×9mm×9mm) with the assigned fixed level of porosity (69 %) were designed as CAD files using Solidworks. Each model was meshed, and the convergence study was conducted. The three models were then imported into a finite element package (ABAQUS). A UMAT code developed by IUT (Isfahan University of Technology) group was used to simulate the mechanical behavior of the shape memory NiTi alloy. All boundary conditions and loading conditions were applied to the models. Compressive mechanical tests were simulated in the finite element, and the resultant equivalent modulus of elasticity, elongations, stress, and strain was estimated. The results show anisotropic behavior within the three different porous structures. With the same level of porosity (i.e., 69 %), equivalent modulus of elasticity was observed to be 48.9, 34.8, and 30.2 GPa for Schwartz-type, Gyroid-type, and Diamond-type, respectively. Moreover, the Schwartz-type scaffold was seen to offer the highest stress at plateau start and the lowest residual strain after unloading, in comparison with the other two types of structure.

Determination of Mechanical Properties of Non-Conventional Reinforcement

2015 ◽  
Vol 662 ◽  
pp. 249-252
Author(s):  
Tomáš Bittner ◽  
Petr Bouška ◽  
Michaela Kostelecká ◽  
Šárka Nenadálová ◽  
Milan Rydval ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Reinforced Concrete ◽  
Modulus Of Elasticity ◽  
Mechanical Tests ◽  
Textile Reinforced Concrete ◽  
Research Project ◽  
Glass Reinforcement

Mechanical tests of samples of basalt and textile glass reinforcement were performed within the solution of the research project GAČR 13-12676S and SGS14/171/OHK1/2T/31. These tests were carried out because of the need to establish elementary mechanical quantities that are tensile strength and modulus of elasticity of non-conventional reinforcement. Both of these quantities are required for further modeling of structures and for designing of the elements made from textile reinforced concrete (TRC) as not being provided by reinforcement manufacturers. The tests were carried out on a total of 12 samples of reinforcement where the first 6 samples were made from textile glass reinforcement (AR-G = Alkali-Resistant Glass) and the remaining 6 samples were prepared from basalt reinforcement. The filament sheaf fibers called roving was used for the production of test specimens.

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