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Search Results: 1 - 10 of 13731 matches for " Mechanical properties "
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Elastic Properties of Clinopyroxene Based Glasses along Diopside (CaMgSi2O6)-Jadeite (NaAlSi2O6) Join  [PDF]
Rinkel Jindal, Widiya Jatmiko, Indra Vir Singh, R. Jayaganthan
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2012, DOI: 10.4236/jmmce.2012.113020
Abstract: The elastic properties of glasses along Diopside (CaMgSi2O6)-Jadeite (NaAlSi2O6) join (Dix - Jd1-x where x=20, 40, 60, 80, 100 mole %), were obtained by the ultrasonic echography technique, at room temperature. The correlation of elastic moduli with the atomic packing density of these glasses was discussed. The derived experimental values of Young’s modulus, bulk modulus, shear modulus and Poisson’s ratio for investigated glasses were compared with those theoretically calculated values in terms of the Makishima–Mackenzie model and the modified model presented by Rocherulle.
Effect of Ultrasound and Xylanase Treatment on the Physical-Mechanical Properties of Bleached Eucalyptus Kraft Pulp  [PDF]
Larisse A.R. Batalha, Juliana C. da Silva, Carolina M. Jardim, Rubens C. Oliveira, Jorge L. Colodette
Natural Resources (NR) , 2011, DOI: 10.4236/nr.2011.22017
Abstract: The modification on the fiber structure of bleached eucalyptus kraft pulp is a very attractive alternative for improve- ments in the properties of paper production. The enzymatic treatment by xylanases and ultrassonic treatments modify the characteristics of the fibers, has been reported. Therefore, the purpose of this study was to evaluate the influence of ultrasonic waves as a facilitator of the action of enzymes (hemicellulase) by modifying the physicochemical nature of fiber eucalyptus Kraft pulp, in order to improve the physical and mechanical properties of the paper. But it was observed the that idea of ultrasound acts as facilitator for action of enzymes can’t be affirmed, since in most properties XA-1 and XA-2 were equal statistically. It may be noted that the junction of ultrasound and xylanase provided improves on tensile index, specific elastic modulus and tensile energy absorption and a decrease of tear index on the mechanical properties of handsheet and it increased the opacity when the ultrasound was applied before xylanase.
Structural, Microstructral, Mechanical and Magnetic Characterization of Ball Milled Tungsten Heavy Alloys  [PDF]
H. Elshimy, Z. K. Heiba, Karimat El-Sayed
Advances in Materials Physics and Chemistry (AMPC) , 2014, DOI: 10.4236/ampc.2014.412027
Abstract: A homemade ball mill was constructed and optimized in order to prepare nano crystallite size of tungsten heavy alloys, with composition of 90W-7Ni-3Fe and 90W-7Ni-3Co in wt%. The samples were mechanically alloyed under high purity of argon atmosphere and were sintered under high vacuumat 1200°C, 1300°C and 1400°C. X-ray diffraction (XRD), Transmission Electron Microscope (TEM), Scanning Electron Microscope (SEM), Energy Dispersive X-ray (EDX), Vickers, ultrasonic techniques and SQUID magnetometer were all used to characterize the studied samples. The sintering temperature and the milling time at which the heavy tungsten alloys were obtained, are discussed in details. The results showed that the tungsten heavy alloys were synthesized and sintered at lower temperature than those prepared by the conventional techniques. Moreover, the strains and relative densities increased with milling time up to 100 hrs; then decreased with further milling. On the other hand, the elastic moduli and hardness increased with milling time up to 200 hrs; then decreased with further milling. The hardness calculated from ultrasonic and measured from Vickers exhibited a similar trend though with different values. The saturated magnetization decreased by increasing the milling time and decreasing the crystallite size.
A Study on Mechanical Properties of PMMA/Hydroxyapatite Nanocomposite  [PDF]
S. M. Zebarjad, S. A Sajjadi, T. Ebrahimi Sdrabadi, S. A Sajjadi, A Yaghmaei, B Naderi
Engineering (ENG) , 2011, DOI: 10.4236/eng.2011.38096
Abstract: This study is focused on the role of nano hydroxyapatite particles on the mechanical properties of PMMA/HA nanocomposites. In order to achieve a proper and homogeneous distribution of HA particles in the polymer matrix, mixer milling process was applied. Wear, compression and three-point bending tests were conducted. It was observed that wear rate decreased by increasing in HA content in both atmosphere and artificial saliva. The results of compression tests showed that the addition of 2.5 percent HA to PMMA promoted ultimate compressive strength, yield strength and modulus while caused to decrease elongation at break. Also it was elucidated that addition of HA more than 2.5 wt.% caused a decrease in both ultimate compressive strength and compression yield strength and an increase in elongation at break. The results of three-point bending tests on the PMMA cements containing 2.5 percent HA demonstrated the maximum bending strength value and modulus among all the HA containing formulations. However there was no direct proportionality between the results of bending tests and the HA content and the addition of HA to PMMA (up to 10 wt.%) did not change the bending properties significantly.
Mechanical and Morphological Properties of Polypropylene/Polyoxymethylene Blends  [PDF]
Sirirat Wacharawichanant, Tanakorn Siripattanasak
Advances in Chemical Engineering and Science (ACES) , 2013, DOI: 10.4236/aces.2013.33026

This work studies the mechanical and morphological properties of polypropylene (PP)/polyoxymethylene (POM) blends. The PP/POM blends were prepared by melting-blend with an internal mixer. The contents of PP were used at 10%, 20%, 30%, 70%, 80% and 90% by weight. The phase morphology of the blends was observed by scanning electron microscope (SEM) due to the mechanical properties depended on the phase morphology. The results show the decrease of the impact strength, Young’s modulus and tensile strength of POM/PP blends with increasing of PP content up to 30 wt% and then increase again with a high PP content. The percent strain at break of the blends increases after adding PP in a range of 70 - 90 wt%. SEM study reveals that the POM/PP blends clearly demonstrate a two-phase matrix-particle microstructure. The results also show that the domain size of dispersed PP or POM phase increases with increasing PP or POM content. The POM domain size is smaller than the PP domain size which leads to a little change of mechanical results of PP.

Strength Characterization of E-glass Fiber Reinforced Epoxy Composites with Filler Materials  [PDF]
K. Devendra, T. Rangaswamy
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2013, DOI: 10.4236/jmmce.2013.16054
Abstract: In this research work, an investigation was made on the mechanical properties of E-glass fiber reinforced epoxy composites filled by various filler materials. Composites filled with varying concentrations of fly ash, aluminum oxide (Al2O3), magnesium hydroxide (Mg(OH)2) and hematite powder were fabricated by standard method and the mechanical properties such as ultimate tensile strength, impact strength and hardness of the fabricated composites were studied. The test results show that composites filled by 10% volume Mg(OH)2 exhibited maximum ultimate tensile strength and hardness. Fly ash filled composites exhibited maximum impact strength.
Effect of Pressure on the Superconducting and Mechanical Properties of Bi1.6Pb0.4Sr1.8Ba0.2Ca2Cu2.2Ni0.8O10+δ System  [PDF]
Ghazala Y. Hermiz, Bushra A. Aljurani, Hassan A. Thabit
Advances in Materials Physics and Chemistry (AMPC) , 2013, DOI: 10.4236/ampc.2013.31007

Solid state reaction method was used to prepare samples of Bi1.6Pb0.4Sr1.8Ba0.2Ca2Cu2.2Ni0.8O10+d. Superconducting and mechanical properties by Vickers microhardness measurements have been carried out to examine the effects of pressure. Electrical measurement demonstrates the best transition temperature was under 0.7 GPa. An improvement of mechanical properties was found when the pressure increases from 0.3 GPa to 0.9 GPa. On the other side an increases of the pressure to 1.1 GPa decrease in the micro hardness, Young modulus and yield strength.

Characterization and Evaluation of Bond Strength of Dental Polymer Systems Modified with Hydroxyapatite Nanoparticles  [PDF]
Vitor César Dumont, Rafael Menezes Silva, Luiz Edmundo Almeida-Júnior, Juan Pedro Bretas Roa, Adriana Maria Botelho, Maria Helena Santos
Journal of Materials Science and Chemical Engineering (MSCE) , 2013, DOI: 10.4236/msce.2013.17003
Abstract: The study modifies an adhesive system with hydroxyapatite nanoparticles as load, characterizing it and evaluate the effectiveness of its bond to dental structure. The middle thirds of healthy premolar tooth crowns were obtained, and each crown was sectioned vertically, resulting in two sections. The sections were divided into ten groups (n = 15), in which resin composite restorations were simulated: (G1E and G1D) conventional adhesive system (SAC); (G2E and G2D) SAC modified with HAP; (G3E and G3D) Primer modified with HAP; (G4E and G4D) monocomponent adhesive system; (G5E and G5D) self-etching adhesive system. The specimens were submitted to the microshear test and characterization technique. There was statistically significant difference (Kruskal-Wallis) between the groups (p < 0.01). G3 presented the highest bond strength to enamel (64.40 MPa, ±7.36) and dentin (39.59 MPa, ±21.46). The majority of specimens were found adhesive fractures. Bond strength to enamel and dentin of the primer modified with HAP of SAC showed higher values.
Mechanical Properties of Potassium Titanate Whisker Reinforced Epoxy Resin Composites  [PDF]
M. Sudheer, K. M. Subbaya, Dayananda Jawali, Thirumaleshwara Bhat
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2012, DOI: 10.4236/jmmce.2012.112016
Abstract: This paper deals with the study of mechanical properties of Potassium Titanate Whisker (PTW) reinforced epoxy based Polymer Matrix Composites (PMCs). Epoxy composites filled with PTW in various content of 0-20 wt% were prepared using the casting technique. Data on neat epoxy is also included for comparison. All tests were conducted at room temperature and as per ASTM standards. It was observed that inclusion of PTW affected most of the mechanical properties of neat epoxy. Density, hardness and heat deflection temperature of neat epoxy were found to increase with the PTW content. However tensile and flexural properties of the developed composites exhibited a varying trend with respect to PTW content. Epoxy filled with 10 wt% PTW showed good improvement in tensile strength and flexural strength of neat epoxy. It was observed that PTW is not beneficial in improving the impact strength of neat epoxy. Composites with 20 wt% PTW exhibited least impact strength. This paper also highlights the possible reasons for variation in the mechanical properties of developed polymer composites.
Molecular Dynamics Simulation of Mechanical Properties for α-SiO2 Crystal  [PDF]
Jierong Guo, Lei Ma
Journal of Modern Physics (JMP) , 2019, DOI: 10.4236/jmp.2019.106040
Abstract: The mechanical properties of the α-SiO2 crystal are studied by molecular dynamics method with Tersoff potential function. The results show that the α-SiO2 crystal goes through elastic deformation, plastic deformation and fracture deformation in the process of uniaxial loading at room temperature. The α-SiO2 is from crystal phase transformation to amorphous phase in plastic deformation. And also by studying the influence of temperature on the tensile mechanical properties of α-SiO2, it finds that the yield strength and elastic modulus of α-SiO2 decrease gradually as the temperature increases. Moreover, the higher the temperature, the lower the fracture stress and fracture strain; the α-SiO2 crystal is easy to be broke under high temperature uniaxial loading. And it also finds that the crack is able to decrease the mechanical properties of α-SiO2 crystal.
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