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11 results on '"Zohdi, Nima"'

3. Evaluation on Material Anisotropy of Acrylonitrile Butadiene Styrene Printed via Fused Deposition Modelling.

Author

Zohdi, Nima, Nguyen, Phan Quoc Khang, and Yang, Richard

Subjects
FUSED deposition modeling, ACRYLONITRILE butadiene styrene resins, ACRYLONITRILE, BUTADIENE, ANISOTROPY, THERMOSETTING polymers
Abstract

Thermoplastic polymers are widely used in industry to generate parts with reasonable production costs, lightweight, chemical stability, sustainability, and recyclability compared to other materials such as metals, metalloids, or even thermoset polymers. The innovative additive manufacturing (AM) techniques, e.g., fused deposition modelling (FDM), can be used to fabricate thermoplastic products with complex geometries and specific properties. However, the mechanical integrity of those FDM-printed plastic parts can be greatly impacted by a phenomenon named material anisotropy. In this study, an experimental study on a popular 3D printing polymer material—acrylonitrile butadiene styrene (ABS)—is performed to determine how FDM process parameters affect the mechanical properties of the printed ABS parts. This study uniquely concentrates on investigating mechanical anisotropy in FDM-printed ABS, delving into a combination of key printing parameters for a comprehensive exploration. Meanwhile, a finite-element-based numerical analysis is also utilised to numerically evaluate the influences of infill percentage and build orientations on the mechanical properties of the 3D-printed ABS materials for comparison. It generates a better understanding of material anisotropy and helps to find the optimal FDM process parameters to print high-quality ABS parts and may attract industrial interests in transitioning from traditional ABS part production methods such as injection moulding or hot pressing to additive manufacturing. [ABSTRACT FROM AUTHOR]

Published
2024
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11. Adsorption of boron using modified multiwalled carbon nanotubes

Author

Zohdi, Nima and Zohdi, Nima

Abstract

Boron is mostly used in the form of boric acid and borates in various industries.However, due to its toxicity to animals and plants, discharge of boron contained waste must be controlled at sustainable and safe level. In order to remove boron from the water to a desirable level to meet the requirement set by the legislation, multi walled carbon nanotubes (MWCNT) was used and modified by using three different chemicals which are glucose, sorbitol and tartaric acid. Surface chemistry of modified-MWCNT (m-MWCNT) was studied through Boehm technique to evaluate the quantity of oxygen containing functional groups. The results showed that tartaric acid m-MWCNT contained the highest amount of oxygen containing functional groups. Also,Fourier Transform Infrared Spectroscopy (FTIR) confirmed that carboxylic groups were formed on the surface of the m-MWCNT. Brunire Emmett Teller (BET) results showed no significant increase in surface area after modification of MWCNTs with these three organic chemicals comparing to the unmodified-MWCNTs. Boron adsorption characteristic of m-MWCNT samples was investigated under different pH, dosage of m-MWCNT, initial boron concentration, contact time and temperature. The tartaric acid m-MWCNT adsorbed the maximum amount of 1.97 mg/g of boron from contaminated water at pH of 6, temperature of 25 C, contact time of 60 min and dosage adsorbent of 0.4 g/l. At the same condition glucose m-MWCNT and sorbitol m-MWCNT adsorbed around 1.53 and 1.14 mg/g of boron respectively. The isotherm study of the adsorption revealed that adsorption behavior was best described by Freundlich model for all three modified samples. Lagergren-first-order, Pseudo-second-order and Intraparticle diffusion models were applied to determine the kinetics of the adsorption process. Pseudo-second order results showed higher coefficient of determination (R2) values for all three modifications comparing to the Lagergren-first-order. Sample with the highest adsorption capacity from

Published
2013

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