Mechanical properties of fibre reinforced mortar exposed to gamma radiation

Environment-responsive hydrogel actuators have attracted tremendous attention due to their intriguing properties. Gamma radiation has been considered as a green cross-linking process for hydrogel synthesis, as toxic cross-linking agents and initiators were not required. In this work, chitosan/agar/P(N-isopropyl acrylamide-co-acrylamide) (CS/agar/P(NIPAM-co-AM)) and CS/agar/Montmorillonite (MMT)/PNIPAM temperature-sensitive hydrogel bilayers were synthesized via gamma radiation at room temperature. The mechanical properties and temperature sensitivity of hydrogels under different agar content and irradiation doses were explored. The enhancement of the mechanical properties of the composite hydrogel can be attributed to the presence of agar and MMT. Due to the different temperature sensitivities provided by the two layers of hydrogel, they can move autonomously and act as a flexible gripper as the temperature changes. Thanks to the antibacterial properties of the hydrogel, their storage time and service life may be improved. The as prepared hydrogel bilayers have potential applications in control devices, soft robots, artificial muscles and other fields.

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Waste Tire Particles and Gamma Radiation as Modifiers of the Mechanical Properties of Concrete

Advances in Materials Science and Engineering ◽

10.1155/2014/327856 ◽

2014 ◽

Vol 2014 ◽

pp. 1-7 ◽

Cited By ~ 4

Author(s):

Eduardo Sadot Herrera-Sosa ◽

Gonzalo Martínez-Barrera ◽

Carlos Barrera-Díaz ◽

Epifanio Cruz-Zaragoza

Keyword(s):

Mechanical Properties ◽

Gamma Radiation ◽

Chemical Properties ◽

Plain Concrete ◽

Cement Matrix ◽

Portland Cement Concrete ◽

High Concentration ◽

Good Tool ◽

Waste Tire ◽

Physical And Chemical

In polymer reinforced concrete, the Young’s modulus of both polymers and cement matrix is responsible for the detrimental properties of the concrete, including compressive and tensile strength, as well as stiffness. A novel methodology for solving such problems is based on use of ionizing radiation, which has proven to be a good tool for improvement on physical and chemical properties of several materials including polymers, ceramics, and composites. In this work, particles of 0.85 mm and 2.80 mm obtained from waste tire were submitted at 250 kGy of gamma radiation in order to modify their physicochemical properties and then used as reinforcement in Portland cement concrete for improving mechanical properties. The results show diminution on mechanical properties in both kinds of concrete without (or with) irradiated tire particles with respect to plain concrete. Nevertheless such diminutions (from 2 to 16%) are compensated with the use of high concentration of waste tire particles (30%), which ensures that the concrete will not significantly increase the cost.

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Effect of Gamma Radiation on the Mechanical Properties of Natural Fabric Reinforced Polyester Composites

Fibres and Textiles in Eastern Europe ◽

10.5604/01.3001.0013.1824 ◽

2019 ◽

Vol 27 (4(136)) ◽

pp. 88-93

Author(s):

K.Z.M. Abdul Motaleb ◽

Md Shariful Islam ◽

Rimvydas Milašius

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Impact Strength ◽

Gamma Radiation ◽

Bending Strength ◽

Polyester Resin ◽

Radiation Doses ◽

Elongation At Break ◽

Bending Modulus ◽

Polyester Composites

Two types of composites:(1) pineapple fabric reinforced polyester resin (Pineapple/PR) and (2) jute fabric reinforced polyester resin (Jute/PR) were prepared and the mechanical properties investigated for various gamma radiation doses ranging from 100-500 krad. Properties like tensile strength, Young’s modulus, elongation-at-break, bending strength, bending modulus and impact strength were increased significantly by 19%, 32%, 45%, 32%, 47% and 20%, respectively, at a dose of 300 krad for Pineapple/PR, and by 47%, 49%, 42%, 45%, 52% and 65%, respectively, at a dose of 200 krad for the Jute/PR composite in comparison to the non-irradiated composite. Gamma radiation improved the mechanical properties, but overdoses of radiation even caused a reduction in them.

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Effect of Gamma Radiation and Endodontic Treatment on Mechanical Properties of Human and Bovine Root Dentin

Brazilian Dental Journal ◽

10.1590/0103-6440201601267 ◽

2016 ◽

Vol 27 (6) ◽

pp. 670-674 ◽

Cited By ~ 6

Author(s):

Veridiana Resende Novais ◽

Priscilla Barbosa Ferreira Soares ◽

Carlla Martins Guimarães ◽

Laís Rani Sales Oliveira Schliebe ◽

Stella Sueli Lourenço Braga ◽

...

Keyword(s):

Mechanical Properties ◽

Flexural Strength ◽

Gamma Radiation ◽

Hardness Test ◽

Knoop Hardness ◽

Endodontic Treatment ◽

Bending Test ◽

Human Teeth ◽

Significant Difference ◽

Root Dentin

Abstract This study evaluated the effect of gamma radiation and endodontic treatment on the microhardness and flexural strength of human and bovine root dentin. Forty single-rooted human teeth and forty bovine incisor teeth were collected, cleaned and stored in distilled water at 4 °C. The human and bovine teeth were divided into 4 groups (n=10) resulting from the combination of two study factors: first, regarding the endodontic treatment in 2 levels: with or without endodontic treatment; and second, radiotherapy in two levels: with or without radiotherapy by 60 Gy of Co-60 gamma radiation fractioned into 2 Gy daily doses five days per week. Each tooth was longitudinally sectioned in two parts; one-half was used for the three-point bending test and the other for the Knoop hardness test (KHN). Data were analyzed by 3-way ANOVA and Tukey HSD test (α=0.05). No significant difference was found for flexural strength values. The human dentin had significantly higher KHN than the bovine. The endodontic treatment and radiotherapy resulted in significantly lower KHN irrespective of tooth origin. The results indicated that the radiotherapy had deleterious effects on the microhardness of human and bovine dentin and this effect is increased by the interaction with endodontic therapy. The endodontic treatment adds additional negative effect on the mechanical properties of radiated tooth dentin; the restorative protocols should be designed taking into account this effect.

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