scholarly journals Caracterización mecánica de conchas amazónicas de Pomacea dolioides (Reeve, 1856)

2018 ◽  
Vol 34 (1) ◽  
pp. 1-11
Author(s):  
Ariana Freire Andrade ◽  
Rodrigo Bíscaro Nogueira
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Mechanical Behavior ◽  
Surface Hardness ◽  
Thickness Variation ◽  
Mollusk Shells ◽  
Low Level ◽  
Freshwater Mollusk ◽  
Floodplain Area

We investigated the mechanical behavior of freshwater mollusk shells, Pomacea dolioides, collected from a floodplain area located in Amazonas, Brazil. With the purpose of characterizing the mechanical properties of the shells, bending, hardness and roughness tests were carried out. To determine the shell flexural strength, a new methodology was proposed for the calculation of it, considering the curved geometry of the specimens taken from the shells. It was also described the mechanical properties as a function of shell position and thickness, variation of the surface hardness along the shell and the low level of superficial irregularity in the inner layer of the shells. Shell presented a mean flexural rupture modulus (MOR) of 128.0 MPa, Rockwell HR15N hardness = 50 ± 8.3 and a low level of irregularities in the inner layer, roughness Ra = 0.160 μm.

Basic Mechanical Properties Research of SAE Latex-Modified Mortar

2015 ◽  
Vol 1088 ◽  
pp. 621-625 ◽  
Author(s):  
Wei Meng
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Mechanical Behavior ◽  
Experimental Research ◽  
Steel Fiber ◽  
Change Trend ◽  
The Law

Through experimental research under the condition of different ratio of polymer and SAE of modified mortar, compressive and flexural strength of change trend, also studied the 1% content of steel fiber on the mechanical behavior of the SAE modified mortar, for in both cases, examined the mortar specimens respectively than the law of the change of compressive and flexural strength, and the conclusion is given.

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.

scholarly journals Polytetrafluorethylene added to acrylic resins: mechanical properties

2010 ◽  
Vol 21 (1) ◽  
pp. 55-59 ◽  
Author(s):  
Fabiana Gouveia Straioto ◽  
Antonio Pedro Ricomini Filho ◽  
Alfredo Júlio Fernandes Neto ◽  
Altair Antoninha Del Bel Cury
Keyword(s):  
Mechanical Properties ◽  
Impact Strength ◽  
Flexural Strength ◽  
Flexural Modulus ◽  
Peak Load ◽  
Surface Hardness ◽  
Acrylic Resin ◽  
Denture Base ◽  
Standard Data ◽  
Acrylic Resins

The addition of different polymers, such as polytetrafluorethylene (PTFE), to denture base resins could be an option to modify acrylic resin mechanical properties. This study evaluated the surface hardness, impact and flexural strength, flexural modulus and peak load of 2 acrylic resins, one subjected to a long and another subjected to a short polymerization cycle, which were prepared with or without the addition of 2% PTFE. Four groups were formed according to the polymerization cycle and addition or not of PTFE. Forty specimens were prepared for each test (10 per group) with the following dimensions: hardness (30 mm diameter x 5 mm thick), impact strength (50 x 6 x 4 mm) and flexural strength (64 x 10 x 3.3 mm) test. The results of the flexural strength test allowed calculating flexural modulus and peak of load values. All tests were performed in accordance with the ISO 1567:1999 standard. Data were analyzed statistically by ANOVA and Tukey's test with the level of significance set at 5%. No statistically significant differences (p>0.05) were found for surface hardness. Flexural strength, impact strength and peak load were significantly higher (p<0.05) for resins without added PTFE. The flexural modulus of the acrylic resin with incorporated 2% PTFE polymerized by long cycle was significantly higher (p<0.05) than that of the other resins. Within the limits of this study, it may be concluded that the addition of PTFE did not improve the mechanical properties of the evaluated acrylic resins.

scholarly journals On the effects of build orientation, strain rate sensitivity and sample thickness on the mechanical behavior of 316l Stainless Steel manufactured by Selective Laser Melting

2021 ◽  
Vol 250 ◽  
pp. 05009
Author(s):  
Hugo Carassus ◽  
Hervé Morvan ◽  
Gregory Haugou ◽  
Jean-Dominique Guerin ◽  
Tarik Sadat ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Strain Rate ◽  
Mechanical Behavior ◽  
Selective Laser Melting ◽  
Strain Rate Sensitivity ◽  
316L Stainless Steel ◽  
Rate Sensitivity ◽  
Thickness Variation ◽  
Laser Melting

The Additive Layer Manufacturing (ALM) for metallic materials has grown in the past few years. However, this process influences the mechanical properties of the constitutive material and consequently those of the finished product. The influence of the thickness and the building direction of 316L Stainless Steel (SS) specimens produced by Selective Laser Melting (SLM) on the quasi-static mechanical behavior has already been reported. Considering the strain rate effect, it has been only studied for tensile properties of vertical specimens up to 102s–1. The aim of this work is to study the influence of the thickness and the building orientation at higher strain rates up to 101s–1 and up to 103s–1 for vertical specimens. Compared to conventional material, 316L SS SLM achieves equal and even better mechanical properties due to a refinement of the microstructure. Anisotropy is observed at the macroscopic level, which is explained by the microstructure with different shapes, orientation and size of grains. A minimum thickness of 0.75mm is recommended to recover the mechanical properties of the conventional 316L SS. A positive strain rate sensitivity is observed in every case. The material anisotropy and the thickness variation do not affect the strain rate sensitivity.

scholarly journals Investigating the Mechanical Properties of ZrO2-Impregnated PMMA Nanocomposite for Denture-Based Applications

Materials ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1344 ◽  
Author(s):  
Saleh Zidan ◽  
Nikolaos Silikas ◽  
Abdulaziz Alhotan ◽  
Julfikar Haider ◽  
Julian Yates
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Impact Strength ◽  
Flexural Strength ◽  
Flexural Modulus ◽  
Surface Hardness ◽  
Bending Test ◽  
Zro2 Nanoparticles ◽  
Control Group ◽  
The Mean

Acrylic resin PMMA (poly-methyl methacrylate) is used in the manufacture of denture bases but its mechanical properties can be deficient in this role. This study investigated the mechanical properties (flexural strength, fracture toughness, impact strength, and hardness) and fracture behavior of a commercial, high impact (HI), heat-cured denture base acrylic resin impregnated with different concentrations of yttria-stabilized zirconia (ZrO2) nanoparticles. Six groups were prepared having different wt% concentrations of ZrO2 nanoparticles: 0% (control), 1.5%, 3%, 5%, 7%, and 10%, respectively. Flexural strength and flexural modulus were measured using a three-point bending test and surface hardness was evaluated using the Vickers hardness test. Fracture toughness and impact strength were evaluated using a single edge bending test and Charpy impact instrument. The fractured surfaces of impact test specimens were also observed using a scanning electron microscope (SEM). Statistical analyses were conducted on the data obtained from the experiments. The mean flexural strength of ZrO2/PMMA nanocomposites (84 ± 6 MPa) at 3 wt% zirconia was significantly greater than that of the control group (72 ± 9 MPa) (p < 0.05). The mean flexural modulus was also significantly improved with different concentrations of zirconia when compared to the control group, with 5 wt% zirconia demonstrating the largest (23%) improvement. The mean fracture toughness increased in the group containing 5 wt% zirconia compared to the control group, but it was not significant. However, the median impact strength for all groups containing zirconia generally decreased when compared to the control group. Vickers hardness (HV) values significantly increased with an increase in ZrO2 content, with the highest values obtained at 10 wt%, at 0 day (22.9 HV0.05) in dry conditions when compared to the values obtained after immersing the specimens for seven days (18.4 HV0.05) and 45 days (16.3 HV0.05) in distilled water. Incorporation of ZrO2 nanoparticles into high impact PMMA resin significantly improved flexural strength, flexural modulus, fracture toughness and surface hardness, with an optimum concentration of 3–5 wt% zirconia. However, the impact strength of the nanocomposites decreased, apart from the 5 wt% zirconia group.

scholarly journals Study of the mechanical behavior of light mortars produced by thermal treatment, with coal waste of Jerada mine (eastern Morocco)

2019 ◽  
Vol 286 ◽  
pp. 03006
Author(s):  
R. Addou ◽  
K. Hannawi Salmo ◽  
Z. Zenasni ◽  
W. P. Agbodjan ◽  
M. Zenasni
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Thermal Treatment ◽  
Flexural Strength ◽  
Mechanical Behavior ◽  
Large Deformations ◽  
Coal Waste ◽  
Acoustic Vibrations ◽  
Rigidity Modulus ◽  
Eastern Morocco

This paper investigates the mechanical properties of light mortars containing coal waste of Jerada mine, as a volume replacement for sand, with different percentages of substitution: 10%, 20% and 50%. The results revealed a decrease in the mechanical properties of composite mortars, including uniaxial compression and flexural strength as well as rigidity modulus. However, the heat treatment improves their ductility, and delays the propagation of cracks. Thus, the developed material is interesting for use in construction, serving as a basis for manufacturing prefabricated blocks treated at 600°C. These elements can be used for applications with large deformations, or with mechanical or acoustic vibrations.

scholarly journals Novel Poly(Methyl Methacrylate) Containing Nanodiamond to Improve the Mechanical Properties and Fungal Resistance

Materials ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3438 ◽  
Author(s):  
Utkarsh Mangal ◽  
Ji-Yeong Kim ◽  
Ji-Young Seo ◽  
Jae-Sung Kwon ◽  
Sung-Hwan Choi
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Flexural Strength ◽  
Methyl Methacrylate ◽  
Vickers Hardness ◽  
Surface Hardness ◽  
Fungal Resistance ◽  
Control Group ◽  
Poly Methyl Methacrylate ◽  
Fungal Adhesion

Herein we evaluate the effect of nanodiamond (ND) incorporation on the mechanical properties of poly(methyl methacrylate) (PMMA) nanocomposite. Three quantities of ND (0.1, 0.3, and 0.5 wt.%) were tested against the control and zirconium oxide nanoparticles (ZrO). Flexural strength and elastic modulus were measured using a three-point bending test, surface hardness was evaluated using the Vickers hardness test, and surface roughness was evaluated using atomic force microscopy (AFM), while fungal adhesion and viability were studied using Candida albicans. Samples were also analyzed for biofilm thickness and biomass in a saliva-derived biofilm model. All groups of ND-PMMA nanocomposites had significantly greater mean flexural strengths and statistically improved elastic modulus, compared to the control and ZrO groups (P < 0.001). The Vickers hardness values significantly increased compared to the control group (P < 0.001) with 0.3% and 0.5% ND. ND addition also gave significant reduction in fungal adhesion and viability (P < 0.001) compared to the control group. Finally, salivary biofilm formation was markedly reduced compared to the ZrO group. Hence, the incorporation of 0.1–0.5 wt.% ND with auto- polymerized PMMA resin significantly improved the flexural strength, elastic modulus, and surface hardness, and provided considerable fungal resistance.

scholarly journals PENGAWETAN KAYU SENGON MELALUI RENDAMAN DINGIN MENGGUNAKAN BAHAN PENGAWET ENBOR SP DITINJAU TERHADAP SIFAT MEKANIK

2016 ◽  
Vol 18 (1) ◽  
pp. 55-64
Author(s):  
Endah Kanti Pangestuti ◽  
Lashari Lashari ◽  
Agus Hardomo
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Large Scale ◽  
Wood Fiber ◽  
Surface Hardness ◽  
Wood Preservation ◽  
Fiber Direction ◽  
Preservation Method ◽  
Engineering State

The use of wood in construction world continues to increase both for the use of structural and non-structural. Needs a very large timber impact on the availability of wood shrinks every year as a result of exploitation by large scale. One attempt to extend the service life of wood is the wood preservation. This study aims to determine mechanical properties of wood by soaking sengon due to cold preservation with preservative EnborSP. The method used is the method of experiments carried out in the Laboratory of Materials of Civil Engineering, Faculty of Engineering, State University of Semarang. The preservation process used isa process with a cold soaking method, with a preservative solution EnborSP with a concentration of 0%, 3%, 6% and 9%. The response observed was the value-the value retention of preservatives, and mechanical properties (compressive strength of parallel fiber direction, flexural strength and surface hardness) of wood. Preservation method applied is cold soaking (for 5 days or 120 hours). Average retention value-average increase of 2.57kg/m3 (3%), 4.89kg/m3 (6%), and 6.74kg/m3 (9%). Value - average compressive strength of parallel to the direction of the wood fiber sengon increase of 149.39kg/cm2 (0%), 156.35kg/cm2 (3%), 187.80kg/cm2 (6%), and 216, 44kg/cm2 (9%). Value average flexural strength sengon increase of 175.36kg/cm2 (0%), 202.55kg/cm2 (3%), 272.64kg/cm2 (6%), and 362.81kg/cm2 (9%). Value average penetration sengon wood decreased from 0.93cm (0%), 0.67cm (3%), 0.57cm (6%), and 0.43cm (9%). This decrease shows that there is an increase in the value of the wood sengon surface hardness.Salah satu usaha untuk memperpanjang umur pemakaian kayu adalah dengan pengawetan kayu. Penelitian ini bertujuan untuk mengetahuisifat mekanik kayu sengon akibat pengawetan secara rendaman dingin dengan bahan pengawet Enbor SP. Metode penelitian yang digunakan adalah metode eksperimen yang dilakukan di Laboratorium Bahandan Laboratorium Kerja KayuTeknik Sipil Fakultas Teknik UniversitasNegeriSemarang.Proses pengawetan yang digunakan adalah proses dengan metode rendaman dingin, dengan larutan bahan pengawet Enbor SP dengan konsentrasi 0 %, 3 %, 6 %, dan 9 %. Respon yang diamati adalah nilai nilai retensi bahan pengawet dan serta sifat mekanis (kuat tekan tekan sejajar arah serat, kuatlentur dan kekerasan permukaan) kayu. Metode pengawetan yang diterapkan adalah rendaman dingin (selama 5 hari atau 120 jam). Nilai retensi rata rata mengalami kenaikan dari 2,57 kg/m3(3 %), 4,89 kg/m3(6 %), dan 6,74 kg/m3(9 %). Nilai rata rata kekuatan tekan sejajar arah serat kayu sengon mengalami kenaikan dari149,39 kg/cm2(0 %), 156,35 kg/cm2(3 %), 187,80 kg/cm2(6 %), dan 216,44 kg/cm2(9 %). Nilai rata rata kekuatan lentur kayu sengon mengalami kenaikan dari 175,36 kg/cm2(0 %), 202,55 kg/cm2(3 %), 272,64 kg/cm2(6 %), dan 362,81 kg/cm2(9%).Nilai rata rata penembusan kayu sengon menurun dari 0,93 cm (0 %), 0,67 cm (3 %), 0,57 cm (6 %), dan 0,43 cm (9 %). Penurunan ini memperlihatkan bahwa ada peningkatan nilai kekerasan permukaan kayu sengon.

scholarly journals Mechanical Properties of Experimental Composites with Different Photoinitiator

2021 ◽  
Author(s):  
Luis Felipe Marques de Resende ◽  
Anderson Catelan ◽  
Kusai Baroudi ◽  
Alan Rodrigo Muniz Palialol ◽  
Alexandre Marques de Resende ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Flexural Strength ◽  
Phosphine Oxide ◽  
Light Emitting Diode ◽  
Surface Hardness ◽  
Triethylene Glycol ◽  
Bottom Surface ◽  
Significance Level ◽  
Depth Of Cure

Abstract Objective The effect of different photoinitiators on mechanical properties of experimental composites was evaluated. Materials and Methods Resin composites were formulated by using a blend of bisphenol A-glycidyl and triethylene glycol (50/50 wt%) dimethacrylate monomers, and 65 wt% of barium aluminium silicate and silica filler particles. Photoinitiators used were 0.2% camphorquinone (CQ) and 0.8% co-initiator (DMAEMA); 0.2% phenyl-propanedione and 0.8% DMAEMA; 0.1% CQ + 0.1% phenyl propanedione and 0.8% DMAEMA; 0.42% mono(acyl)phosphine oxide (MAPO); and 0.5% bis(acyl)phosphine oxide (BAPO). Specimens (n = 10) were light cured by using a multiple-emission peak light-emitting diode for 20 seconds at 1,200 mW/cm2 of irradiance and Knoop hardness and plasticization, depth of cure, flexural strength, and elastic modulus were evaluated. Data were statiscally analyzed at significance level of α = 5%. Results Experimental composites containing MAPO and BAPO photoinitiators showed the highest values of flexural strength, elastic modulus, top surface hardness, and lower hardness reduction caused by alcohol compared with CQ. Composites containing CQ and PPD showed similar results, except for depth of cure and hardness of bottom surface. Conclusion BAPO and MAPO showed higher flexural strength, elastic modulus, hardness on top surface, and lower polymer plasticization to CQ.

scholarly journals Denture base adaptation, retention, and mechanical properties of BioHPP versus nano-alumina-modified polyamide resins

2021 ◽  
Vol 15 (4) ◽  
pp. 239-246
Author(s):  
Radwa Mohsen Kamal Emera ◽  
Reham Mohammed Abdallah
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Surface Hardness ◽  
Base Material ◽  
Alumina Nanoparticles ◽  
Control Group ◽  
Denture Base ◽  
Promising Alternative ◽  
Base Materials ◽  
Group I

Background. Continuous development of denture base materials has led to the introduction of innovative alternatives to polymethyl methacrylate. The present study aimed to evaluate the mechanical properties, adaptation, and retention of alumina nanoparticles (Al2 O3 NPs) modified polyamide resin versus BioHPP (high-performance polymer) denture base materials. Methods. Four groups of specimens, one control (group I) (unmodified polyamide) and two groups (groups II and III) (2.5 and 5 wt% Al2 O3 NP-modified polyamide, respectively) versus BioHPP specimen group (group IV), were tested for surface microhardness and flexural strength. Complete dentures fabricated from 5 wt% Al2 O3 NP-modified polyamide resin and BioHPP were used to evaluate denture base adaptation and retention. Results. The higher concentration in the alumina NP-modified polyamide group (5 wt%) demonstrated significantly higher flexural strength values and insignificantly higher hardness values than the lower concentration (2.5 wt%). There was a significant increase in the BioHPP group in both flexural strength and surface hardness compared to all polyamide groups. A statistically insignificant difference was observed between the two denture base materials regarding mean misfit values of the calculated total tissue surface area and four of the total seven evaluated areas. Satisfactory and comparable retention values were observed for both denture base materials. Conclusion. BioHPP and Al2 O3 NP-modified polyamide resin could be used as a promising alternative denture base material with good adaptation, retention, and mechanical properties.

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