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1.
Sci Rep ; 14(1): 6313, 2024 03 15.
Artículo en Inglés | MEDLINE | ID: mdl-38491047

RESUMEN

The design cement mix of grade 350 was created in accordance with Egyptian Standards by partially substituting the fine aggregate with WPVC waste in various weight percentages (10, 20, 30, 40, 50, 75, and 100%). A control mix with 0% replacement was also prepared. The W/C ratio was about 0.5 for all mixes. Compressive, flexure strength, bulk density, and absorption tests were studied. For WPVC replacement, until 30%, compressive strength and flexure strength are acceptable with respect to standerds. Thermal treatment at 200 °C improves the compressive strength, flexure strength and water absorption for 20% WPVC only. The dielectric properties of all cement paste mixes before and after heat treatment, over a frequency range (0.1-106 Hz), were measured as a function of frequency. For dielectric properties and conductivity, an improvement was obtained until 30% WPVC. After this percentage, the dielectric properties and the conductivity got worse. So, cement paste with 30% WPVC as replacement of sand is the optimum ratio with conductivity in range of 10-12 S/cm, which is a good choice for antistatic cement paste applications (10-10-10-12 S/cm). The antimicrobial efficacy of the prepared cement samples of WPVC concentrations (0, 20 and 30) % were studied, the number of grown microbial colonies decreased for all the samples compared to control tap water and decreased by introducing WPVC into the cement paste sample. So, it is recommended to use these samples in places that should be carefully shielded from bacterial infections and static electric charge dangers.


Asunto(s)
Cementos para Huesos , Materiales de Construcción , Fuerza Compresiva , Resistencia Flexional , Agua
2.
Sci Rep ; 13(1): 13419, 2023 Aug 17.
Artículo en Inglés | MEDLINE | ID: mdl-37591919

RESUMEN

Currently, the conversion of biomass to produce high-valued biofuels such as biodiesel and bio-jet fuel has attached booming interests, when used for partial replacement of petroleum fuels in different ratios is a promising solution due to the problem of depleting petroleum reserves and environmental purposes. Non-edible Jatropha oil can be transformed to biofuel when subjected to were hydrocracking at hydrogen pressure using an activated natural clay as a catalyst in a high pressure batch reactor. The type of product and its quality and quantity depend on the process conditions such as reaction time, temperature, and catalyst type, form, and amount. The present work aims to study the hydrocracking process of Jatropha oil at different operating conditions. The catalyst is characterized using SEM, FTIR, XRF, and XRD. The effect of process conditions variation have been studied and discussed. The results showed the highest yield of 40% bio-jet fuel was achieved at a temperature of 350 °C, H2 pressure of 4 bar, and reaction time of 18 min. the bio-jet fuel products were tested and their specifications were conformed to ASTM D1655 specifications, viz the freezing point (-56 °C), the flash point (53 °C), and existent gum content (5.9 mg/100 ml).

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