EFFECT OF DIFFERENT GAMMA RADIATION DOSES ON THE MECHANICAL PROPERTIES OF ESTHETIC RESTORATIONS

2017 ◽  
Vol 63 (4) ◽  
pp. 3955-3964
Author(s):  
Ahmed Aziz
2019 ◽  
Vol 27 (4(136)) ◽  
pp. 88-93
Author(s):  
K.Z.M. Abdul Motaleb ◽  
Md Shariful Islam ◽  
Rimvydas Milašius

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.


2012 ◽  
Vol 11 (7) ◽  
pp. 1355-1360
Author(s):  
Clement Ionescu ◽  
Liana Simona Sbirna ◽  
Monica Daniela Mateescu ◽  
Clementina Sabina Moldovan ◽  
Sebastian Sbirna

2016 ◽  
Vol 3 (3) ◽  
pp. 209-214
Author(s):  
Rania Hindi ◽  
Hala Hazzaa ◽  
Doaa El-Sharkawy

2013 ◽  
Vol 443 (1-3) ◽  
pp. 417-423 ◽  
Author(s):  
E. Ordóñez-Regil ◽  
A. Contreras-Ramírez ◽  
S.M. Fernández-Valverde ◽  
P.R. González-Martínez ◽  
H. Carrasco-Ábrego

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1753
Author(s):  
Weixian Huo ◽  
Heng An ◽  
Shuquan Chang ◽  
Shengsheng Yang ◽  
Yin Huang ◽  
...  

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.


2014 ◽  
Vol 77 (10) ◽  
pp. 1768-1772 ◽  
Author(s):  
ANA CAROLINA B. REZENDE ◽  
MARIA CRYSTINA IGARASHI ◽  
MARIA TERESA DESTRO ◽  
BERNADETTE D. G. M. FRANCO ◽  
MARIZA LANDGRAF

This study evaluated the effects of irradiation on the reduction of Shiga toxin–producing Escherichia coli (STEC), Salmonella strains, and Listeria monocytogenes, as well as on the sensory characteristics of minimally processed spinach. Spinach samples were inoculated with a cocktail of three strains each of STEC, Salmonella strains, and L. monocytogenes, separately, and were exposed to gamma radiation doses of 0, 0.2, 0.4, 0.6, 0.8, and 1.0 kGy. Samples that were exposed to 0.0, 1.0, and 1.5 kGy and kept under refrigeration (4°C) for 12 days were submitted to sensory analysis. D10-values ranged from 0.19 to 0.20 kGy for Salmonella and from 0.20 to 0.21 for L. monocytogenes; for STEC, the value was 0.17 kGy. Spinach showed good acceptability, even after exposure to 1.5 kGy. Because gamma radiation reduced the selected pathogens without causing significant changes in the quality of spinach leaves, it may be a useful method to improve safety in the fresh produce industry.


2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Eduardo Sadot Herrera-Sosa ◽  
Gonzalo Martínez-Barrera ◽  
Carlos Barrera-Díaz ◽  
Epifanio Cruz-Zaragoza

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.


1964 ◽  
Vol 44 (2) ◽  
pp. 188-194 ◽  
Author(s):  
H. B. Heeney ◽  
W. M. Rutherford ◽  
K. F. MacQueen

The effects of gamma radiation doses of 110,000, 220,000, and 330,000 rad on the storage life and quality of two varieties of strawberries stored at 40°, 55°, and 70° F were studied. Results indicated that a dose of 330,000 rad prevented fungal development of the Redcoat variety stored for 26 days at 40° F. The fungal-free period was sharply reduced at lower radiation doses or at higher storage temperatures. Under the conditions of this trial there was no apparent effect of radiation on appearance or texture of fruit.In organoleptic tests in the first two weeks of storage observers were not able to differentiate between radiation treatments. There was some preference for treated berries as the storage period increased. After 20 days the flavor of the fruit deteriorated very rapidly and it soon became commercially unacceptable.


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