Straight versus modular nail: Analysis of mechanical properties two knee arthrodesis methods.

2020 ◽  
Author(s):  
Jerzy Białecki ◽  
Marcin Para ◽  
Andrzej Sobolewski ◽  
Maciej Kogut ◽  
Paweł Bartosz
Keyword(s):  
Mechanical Properties ◽  
Comparative Analysis ◽  
Mechanical Strength ◽  
Weight Bearing ◽  
Mechanical Tests ◽  
Bending Test ◽  
Implant Design ◽  
Knee Arthrodesis ◽  
Femoral Nail ◽  
Clinical Cases

Abstract Background Complications after arthroplasty often result in irreversible disability. In some cases for the extremity to be salvaged, the permanent knee joint arthrodesis is the last-chance procedure. Modular implant design simplifies surgical technique but modularity may potentially compromise mechanical strength of an implant. Mechanical properties of the implant are particularly important in case of knee arthrodesis without bone-on-bone contact where forces during gait and weight bearing are transmitted directly through the nail. The aim of this article was to perform comparative analysis of the mechanical properties of modular nail CHARFIX2 FN, when compared to the femoral nail, used for knee arthrodesis; and to analyze the effectiveness of treatment with use of this nail based on the observations of clinical cases. Methods Comparative analysis of: the static 4-point bending test, dynamic 4-point bending test and static torsion test. All tests were performed in accordance with requirements of ASTM F 1264. A clinical analysis of 5 cases, in which CHARFIX2 FN nails were used, was also performed. Results Based on the results of mechanical tests, the strength characteristics of CHARFIX2 FN nail have been found superior and more advantageous than corresponding features of the standard femoral nail. For CHARFIX2 FN nail, the median for flexural stiffness was almost 4 times higher and for maximum torque value was almost 2 times higher when compared to the femoral nail. Observations of the clinical cases gave satisfactory results. Conclusions The obtained mechanical tests present significant differences between CHARFIX2 FN and the femoral nail in mechanical strength and, therefore, its improved stability and safety for patients during walking. It can be used for permanent knee immobilization with satisfactory clinical results. The functional outcomes and subjective measurements of pain in patients treated with CHARFIX2 FN group are satisfying.

scholarly journals Processing of Al2O3-AlN Ceramics and Their Structural, Mechanical, and Tribological Characterization

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6055
Author(s):  
Dheeraj Varanasi ◽  
Monika Furkó ◽  
Katalin Balázsi ◽  
Csaba Balázsi
Keyword(s):  
Mechanical Properties ◽  
Aluminum Nitride ◽  
Hot Isostatic Pressing ◽  
Xrd Analysis ◽  
Mechanical Tests ◽  
Oxidation Time ◽  
Bending Test ◽  
Coarse Powder ◽  
Powder Particles ◽  
Tribological Characterization

The aim of this study is to present a novel, lower sintering temperature preparation, processing, structural, mechanical, and tribological testing of the AlN-Al2O3 ceramics. The precursor powder of AlN was subjected to oxidation in ambient environment at 900 °C for 3, 10, and 20 h, respectively. These oxidized powders were characterized by SEM and XRD to reveal their morphology, phase, and crystal structure. The SEM results showed coarse powder particles and the presence of aluminum oxide (Al2O3) phase at the surface of aluminum nitride (AlN). The XRD analysis has shown increasing aluminum-oxy-nitride conversion of aluminum nitride as the holding time of oxidation increased. The highest percentage of conversion of AlN powder to AlN-Al2O3 was observed after 10 h. Simultaneously the powders were compacted and sintered using the hot isostatic pressing (HIP) under inert environment (N2 gas) at 1700 °C, 20 MPa for 5 h. This led to the compaction and increase in density of the final samples. Mechanical tests, such as bending test and tribology tests, were carried out on the samples. The mechanical properties of the samples were observed to improve in the oxidized samples compared to the precursor AlN. Moreover, applying longer oxidation time, the mechanical properties of the sintered samples enhanced significantly. Optimum qualitative (microstructure, oxide percentage) and quantitative (tribology, hardness, and bending tests) properties were observed in samples with 10-h oxidation time.

scholarly journals Mechanical Response of Ni-Based CU5MCuC Alloy to Different Stabilization Thermal Treatments

2020 ◽  
Author(s):  
Andrea Gruttadauria ◽  
Silvia Barella ◽  
Claudia Fiocchi
Keyword(s):  
Mechanical Properties ◽  
Corrosion Resistance ◽  
Mechanical Strength ◽  
Intergranular Corrosion ◽  
Mechanical Response ◽  
Annealing Treatment ◽  
Mechanical Tests ◽  
Thermal Treatments ◽  
Stabilization Treatment ◽  
Cr System

Abstract The Ni–Fe–Cr system is the basis of a series of commercial alloys featuring chemical–physical characteristics that allow them to be used in a variety of fields where excellent resistance to aggressive environments is required. In this scenario, the CU5MCuC alloy, the foundry counterpart of Alloy 825, is proving successful in the petrochemical field thanks to its good corrosion resistance in acidic and highly oxidizing environments. Intergranular corrosion resistance, critical for this material, is ensured by the stabilization treatment that allows precipitation of Nb carbides. Strengthening of this alloy takes place only via a solid solution. Therefore, its mechanical properties depend on the solution annealing treatment: often this treatment alone does not make it possible to reach the UTS imposed by the ASTM-A494 standard. In this work, the possibility of using stabilization treatment to increase mechanical strength as well was considered. Treatments, with different combinations of time and temperature, were carried out in order to modify the material’s microstructure. After the thermal treatments, microstructural analyses, mechanical tests and (pitting and intergranular) corrosion and resistance tests were carried out to identify optimal treatment parameters in order to promote the evolution of microstructural constituents capable of improving mechanical strength without decreasing corrosion resistance. The treatment that achieves the best compromise between mechanical properties and corrosion resistance is stabilization at 970 °C for 4 h.

scholarly journals Effect of Camphorquinone Concentration in Physical-Mechanical Properties of Experimental Flowable Resin Composites

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Dayany da Silva Alves Maciel ◽  
Arnaldo Bonfim Caires-Filho ◽  
Marta Fernandez-Garcia ◽  
Camillo Anauate-Netto ◽  
Roberta Caroline Bruschi Alonso
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Flexural Strength ◽  
Mechanical Strength ◽  
Surface Hardness ◽  
Degree Of Conversion ◽  
Bending Test ◽  
Resin Matrix ◽  
Shrinkage Stress ◽  
Depth Of Cure

The aim of this study was to evaluate the effect of camphorquinone concentration in physical-mechanical properties of experimental flowable composites in order to find the concentration that results in maximum conversion, balanced mechanical strength, and minimum shrinkage stress. Model composites based on BISGMA/TEGDMA with 70% wt filler loading were prepared containing different concentrations of camphorquinone (CQ) on resin matrix (0.25%, 0.50%, 1%, 1.50%, and 2% by weight). Degree of conversion was determined by FTIR. Surface hardness was assessed before and after 24 h ethanol storage and softening rate was determined. Depth of cure was determined by Knoop hardness evaluation at different depths. Color was assessed by reflectance spectrophotometer, employing the CIE-Lab system. Flexural strength and elastic modulus were determined by a three-point bending test. Shrinkage stress was determined in a Universal Testing Machine in a high compliance system. Data were submitted to ANOVA and Tukey’s test (α = 0.05). The increase in CQ concentration caused a significant increase on flexural strength and luminosity of composites. Surface hardness was not affected by the concentration of CQ. Composite containing 0.25% wt CQ showed lower elastic modulus and shrinkage stress when compared to others. Depth of cure was 3 mm for composite containing 1% CQ and 2 mm for the other tested composites. Degree of conversion was inversely correlated with softening rate and directly correlated with elastic modulus and shrinkage stress. In conclusion, CQ concentration affects polymerization characteristics and mechanical strength of composites. The concentration of CQ in flowable composite for optimized polymerization and properties was 1% wt of the resin matrix, which allows adequate balance among degree of conversion, depth of cure, mechanical properties, and color characteristics of these materials.

Effects of different exercise modes on mineralization, structure, and biomechanical properties of growing bone

2003 ◽  
Vol 95 (1) ◽  
pp. 300-307 ◽  
Author(s):  
T. H. Huang ◽  
S. C. Lin ◽  
F. L. Chang ◽  
S. S. Hsieh ◽  
S. H. Liu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Weight Bearing ◽  
Training Session ◽  
Exercise Group ◽  
Bending Test ◽  
Swimming Exercise ◽  
Control Group ◽  
Mineral Density ◽  
Bone Mechanical Properties ◽  
Content Ratio

Weight bearing during exercise plays an important role in improving the mechanical properties of bone. The effect on bone of non-weight-bearing exercise such as swimming remains controversial. To investigate the effects of exercise mode on growing bone, 29 male Wistar rats (7 wk old) were randomly assigned to a running exercise group (Run, n = 9), a swimming exercise group (Swim, n = 10), or a nonexercise control group (Con, n = 10). During an 8-wk training session (20–60 min/day, 5 days/wk), the Run rats were trained at progressively increasing running speeds (12–22 m/min), and weights attached to the tail of the Swim rats were progressively increased from 0 to 2% of their body weight. The bone mineral density of the proximal tibiae of the Run rats was significantly higher than in the Swim ( P < 0.05). Femoral wet weights of the two exercise groups were significantly higher than in the control group ( P < 0.05). Interestingly, the percent difference between the tissue wet weight and dry weight (water content ratio), which is related to bone mechanical properties, was significantly higher in the tibiae of the Swim rats and the femora of both exercise groups compared with controls ( P < 0.05). Extrinsic as well as intrinsic biomechanical material properties were measured in a three-point bending test. Bone mechanical properties of the tibiae and femora of rats in the Swim and Run groups were significantly greater than those in the control group ( P < 0.05). In summary, different modes of exercise may benefit bone mechanical properties in different ways. The specific effects of swimming exercise (non-weight-bearing exercise) on bone require further study.

scholarly journals Effect of Alteration on the Geochemistry and Mechanical Properties of Granite from Pingjiang, Hunan Province, China

2021 ◽  
Author(s):  
Minghao Ren ◽  
Wei Wang ◽  
Zhiquan Huang ◽  
Shanggao Li ◽  
Qi Wu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Strength ◽  
Hydrothermal Alteration ◽  
Trace Element Analysis ◽  
Mechanical Tests ◽  
Hydrothermal Fluids ◽  
Hunan Province ◽  
Element Analysis ◽  
Mineral Components ◽  
Low Degrees

Abstract The effect of alteration on the geochemistry and mechanical properties of granite from Pingjiang, Hunan Province, China was investigated. Six weathered and 14 hydrothermally altered samples in three footrills (PD2, PD3, and PD4) were collected for mechanical tests and major and trace element analysis. The results show that the relationship between mechanical strength and the degree of alteration, irrespective of whether this is due to weathering or hydrothermal alteration, can be described by an exponential equation. This implies that the mechanical strength decreases rapidly even at low degrees of alteration. Granite Na2O, CaO, K2O, and SiO2 contents were lowered due to weathering, whereas Fe2O3T contents increased significantly due to Fe2+ oxidation. Based on the hypothesis that Al and Zr are immobile during the hydrothermal alteration, the mobility indexes of various elements were calculated for the hydrothermally altered samples. In general, TiO2, K2O, Fe2O3T, Th, Hf, Co, Ni, and V contents were unaffected by hydrothermal alteration; Na2O, Sr, Nd, Sm, and Pb contents were lowered by hydrothermal alteration; and SiO2, Rb, Cr, U, Zn, Mn, and Cs contents were increased due to reactions with the hydrothermal fluids. Even immobile elements, such as Sm, Nd, V, and Cr, were mobilized by high-temperature hydrothermal fluids. To assess the degree of hydrothermal alteration, a new model is required that can account for the effects of the different mineral components.

Effect of temperature on the mechanical properties of polypropylene–talc composites

2017 ◽  
Vol 31 (7) ◽  
pp. 896-912 ◽  
Author(s):  
AO Bouakkaz ◽  
A Albedah ◽  
B Bachir Bouiadjra ◽  
Sohail MA Khan ◽  
F Benyahia ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Strength ◽  
Temperature Variation ◽  
Temperature Increase ◽  
Mechanical Tests ◽  
Effect Of Temperature ◽  
Dynamic Mechanical ◽  
Tensile Impact ◽  
Negative Effect ◽  
Impact Bending

In this study, the effect of the temperature and talc concentration on the mechanical properties of the polypropylene (PP) + talc composite is analysed. Tensile, impact, bending and dynamic mechanical tests were carried out to evaluate the mechanical properties of PP + talc composite and to analyse the effect of temperature variation on these properties. The obtained results show that the temperature increase has a very negative effect on the mechanical strength of the PP–talc composite but it can be significantly reduced by the augmentation of the talc content.

Thermal and Mechanical Properties of Natural Rubber/Rice Starch Interpenetrating Network Hydrogel

2013 ◽  
Vol 844 ◽  
pp. 77-80
Author(s):  
Warisada Sila-On ◽  
Jatuporn Pratoomted ◽  
Utsana Puapermpoonsiri ◽  
Chaiwute Vudjung ◽  
Wiwat Pichayakorn
Keyword(s):  
Mechanical Properties ◽  
Natural Rubber ◽  
Mechanical Strength ◽  
Natural Rubber Latex ◽  
Amorphous Structure ◽  
Mechanical Tests ◽  
Rice Starch ◽  
Thermal And Mechanical Properties ◽  
Interpenetrating Networks ◽  
Scanning Calorimetry

Novel hydrogels based on natural rubber latex (NRL) and rice starch (RSt) (1:2 ratio) were prepared with various amount of N,N-methylenebisacrylamide (MBA) and 2.5 phr of maleic acid to form interpenetrating networks (IPN) using free-radical polymerization technique. The thermal and mechanical properties were performed by differential scanning calorimetry and mechanical tests. From data obtained, the change in Tg of rubber and melting point of RSt indicated that polymer-polymer interaction could be formed in IPN hydrogel. The higher amount addition of MBA created more mechanical strength of IPN hydrogels caused by the higher of interlacement formation. However, their mechanical strength of such hydrogels was lower than that of NRL alone due to the formation of amorphous structure in IPN hydrogel. These IPN hydrogels also improved the swelling property which will be utilized for wound healing application.

scholarly journals Thermal and Mechanical Assessment of PLA-SEBS and PLA-SEBS-CNT Biopolymer Blends for 3D Printing

2021 ◽  
Vol 11 (13) ◽  
pp. 6218
Author(s):  
Balázs Ádám ◽  
Zoltán Weltsch
Keyword(s):  
Mechanical Properties ◽  
3D Printing ◽  
Mechanical Tests ◽  
The Other ◽  
Raw Material ◽  
Bending Test ◽  
Thermal And Mechanical Properties ◽  
Scanning Calorimetry ◽  
Partial Fracture ◽  
The Impact

Polylactic acid (PLA) is one of the most promising biopolymers often used as a raw material in 3D printing in many industrial areas. It has good mechanical properties, is characterized by high strength and stiffness, but unfortunately, it has some disadvantages; one is brittleness, and the other is slow crystallization. Amounts of 1–5% SEBS (styrene-ethylene-butylene-styrene) thermoplastic elastomer were blended into the PLA and the thermal and mechanical properties were investigated. DSC (Differential Scanning Calorimetry) measurements on the filaments have shown that SEBS increases the initial temperature of crystallization, thereby acting as a nucleating agent. The cooling rate of 3D printing, on the other hand, is too fast for PLA, so printed specimens behave almost amorphously. The presence of SEBS increases the impact strength, neck formation appears during the tensile test, and in the bending test, the mixture either suffers partial fracture or only bends without fracture. Samples containing 1% SEBS were selected for further analysis, mixed with 0.06 and 0.1% carbon nanotubes (CNTs), and tested for thermal and mechanical properties. As a result of CNTs, another peak appeared on the DSC curve in addition to the original single-peak crystallization, and the specimens previously completely broken in the mechanical tests suffered partial fractures, and the partially fractured pieces almost completely regained their original shape at the end of the test.

Effect of Pouring Temperature on Mechanical Properties and Microstructures of Aluminium Matrix Composite Strengthened by CNT with Stir Casting Method

2020 ◽  
Vol 988 ◽  
pp. 30-35
Author(s):  
Muhammad Syahid ◽  
Lukmanul H. Arma ◽  
Hairul Arsyad ◽  
Zulfikar A.R. Suwardi
Keyword(s):  
Mechanical Properties ◽  
Mechanical Strength ◽  
Matrix Composite ◽  
Hardness Test ◽  
Stir Casting ◽  
Mechanical Tests ◽  
Aluminium Matrix ◽  
Casting Method ◽  
Pouring Temperature ◽  
Aluminium Matrix Composite

Aluminium matrix composite reinforced Carbon nanoTubes are widely developed because it can increase mechanical strength without reducing its ductility. One of the AMC / CNT manufacturing processes is through the stir casting method. The challenge of the Al / CNT manufacturing process is the occurrence of agglomeration and CNT not homogeneous so that the right casting parameters are needed to obtain optimal results. The purpose of this study was to analyse the effect of pouring temperature on the mechanical strength and microstructure of AA6061 by adding Carbon Nanotube (CNT) through the stir casting method. The CNT is added by 0.1% wt and pouring temperature at 700 °C, 730 °C and 760 °C. Mechanical tests carried out were tensile test, hardness test, and impact test. The highest value of hardness and tensile strength was obtained at the pouring temperature of 700 °C are78 HV and 80.97 MPa. Lower pouring temperature causes smaller grain size so that it has higher strength. The distribution of hardness values ​​at the top, middle and bottom of the specimen is not evenly distributed, but does not differ greatly for all pouring temperatures. The highest value of impact strength is obtained at the pouring temperature of 760 °C which is 0.128 J/mm2. Microstructure was shown the addition of CNTs caused the size of primary silicon and aluminium grains to be small which would increase the mechanical properties.

Effect of silver nitrate on some mechanical properties of heat polymerizing acrylic resins

2019 ◽  
Vol 14 (1) ◽  
pp. 110
Author(s):  
Assiss. Prof. Dr. Sabiha Mahdi Mahdi ◽  
Dr. Firas Abd K. Abd K.
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Silver Nitrate ◽  
Surface Hardness ◽  
Mechanical Tests ◽  
Hardness Tester ◽  
Acrylic Resins ◽  
The Difference

Aim: The aimed study was to evaluate the influence of silver nitrate on surfacehardness and tensile strength of acrylic resins.Materials and methods: A total of 60 specimens were made from heat polymerizingresins. Two mechanical tests were utilized (surface hardness and tensile strength)and 4 experimental groups according to the concentration of silver nitrate used.The specimens without the use of silver nitrate were considered as control. Fortensile strength, all specimens were subjected to force till fracture. For surfacehardness, the specimens were tested via a durometer hardness tester. Allspecimens data were analyzed via ANOVA and Tukey tests.Results: The addition of silver nitrate to acrylic resins reduced significantly thetensile strength. Statistically, highly significant differences were found among allgroups (P≤0.001). Also, the difference between control and experimental groupswas highly significant (P≤0.001). For surface hardness, the silver nitrate improvedthe surface hardness of acrylics. Highly significant differences were statisticallyobserved between control and 900 ppm group (P≤0.001); and among all groups(P≤0.001)with exception that no significant differences between control and150ppm; and between 150ppm and 900ppm groups(P>0.05).Conclusion: The addition of silver nitrate to acrylics reduced significantly the tensilestrength and improved slightly the surface hardness.

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