Wyniki wyszukiwania - BazTech

1

Studying the influence of waste glass and montmorillonite powders on the thermal conductivity and hardness of poly(methyl methacrylate) polymer matrix

Almansoori A., Ghadban R. A., Ali M. H., Sabri M. M.

Journal of Achievements in Materials and Manufacturing Engineering

|

2023

|

Vol. 118, nr 2

49--56

EN

Purpose: The present study aims to evaluate the effect of montmorillonite nanoclay (MMT) and waste glass powder (WGP) on the hardness and thermal conductivity of PMMA polymer composites. Thus, this study concentrates on the potential use of MMT and WGP as reinforcements, in different concentrations, in PMMA polymer matrix, with the expectation of improving the performance of PMMA polymer composites in various applications. Design/methodology/approach: There is a growing demand for PMMA with increased mechanical properties and thermal stability for applications where inorganic glass would fail. Montmorillonite (MMT) clay and Waste Glass Powder (WGP) have physical and chemical properties compatible with PMMA. Therefore, they could potentially enhance PMMA’s hardness and thermal conductivity. Silicon dioxide in glass silica and MMT and octahedral aluminium hydroxide sheet in MMT can strengthen both covalent and hydrogen bonding architecture in PMMA composite for better mechanical strength and thermal conductivity. Thus, PMMA composites were designed by combining MMT powder and WGP powder in different ratios before being incorporated into the PMMA polymer matrix and tested for hardness and thermal conductivity. Findings: The present study measured Brinell Hardness (HB) and electrical conductivity values of four PMMA composites containing different proportions of MMT and WGP. MMT/WGP filler mix had optimal hardiness (HB number = 74) when glass content was 1% (3MMT1G) or better still (HB number = 63) when an equal mix ratio was used (1MMT1G). PMMA composite with 3MMT1G also had the highest thermal conductivity (0.01899W/m.K-1). However, the higher the glass content, the lower the thermal conductivity of the PMMA composite. Thus, the present study has demonstrated that 3MMT1G filler was the best for enhancing the thermal and mechanical properties of PMMA composite. Research limitations/implications: The results of this study demonstrate the potential of this new composite material for a variety of applications. Further research is needed to explore the full potential of this material and to develop new and improved versions. Practical implications: Reusing waste glass as filler materials in composites requires minimal processing and therefore has lower environmental impacts than synthetic options. Originality/value: Experimental data from the present study has provided new insights into Glass/MMT mix design in PMMA composites. The PMMA composite containing 3MMT1G exhibited the best hardness and thermal conductivity characteristics. Thus, the present study has successfully optimised Glass/MMT mix design for PMMA composite for applications requiring these features.

2

Towards the optimization of process parameters for impact strength of natural fiber reinforced composites: Taguchi method

Yusuf S. S., Islam M. N., Ali M. H., Akram M. W., Siddique M. A.

Advances in Materials Science

|

2020

|

Vol. 20, nr 2(64)

54--70

EN

This paper presents an investigation of impact strength of sponge gourd, coir, and jute fibers reinforced epoxy resin-based composites. Impact strength of specimens, made of composites with various proportions of wt% ratio of resin and hardener, wt% of resin and hardener, wt% ratio of sponge gourd and jute, wt% ratio of sponge gourd and coir, was measured. Design of experiment was done by Taguchi method using four control factors with three levels. Effect of the above control factors on impact strength was examined and the best combinations of control factors are advised. Confirmation test was performed by using this combination and the percentage of contribution of the above factors on impact strength was investigated by Analysis of Variance (ANOVA). Contour and interaction plots provide helpfully examines to explore the combined influences of different control factors on output characteristics. The regression equation represents a mathematical model that relates control factors with impact strength.

3

Distribution and speciation of Fe, Mn, Zn, Cu, Pb and P in surface sediments of Lake Mariut, Egypt

Abdel-Satar A. M., Ali M. H., Goher M. E.

Oceanological and Hydrobiological Studies

|

2017

|

Vol. 46, No. 2

154--167

EN

Lake Mariut is suffering from pollution as it receives industrial effluents and a mix of sewage from different drains, often lacking treatment systems. Sequential extraction procedures were applied for the speciation of heavy metals (Fe, Mn, Zn, Cu and Pb) and P in the lake sediment to evaluate their potential bioavailability. Total concentrations of metals had low values compared with the sediment quality guidelines. The chemical speciation data for Mn and Zn indicate a potential pollution level since the non-residual fractions contain up to 77.6 and 64.9% (respectively) of the total metal content. However, Fe, Cu and Pb are mostly linked to the inert fraction. Risk assessment of metals was carried out using the mobility factor, the contamination factor, the risk assessment code and the enrichment factor. All the analytical approaches indicated the accumulation of pollutants exceeding the adsorptive capacity of Lake Mariut sediments. The organic phosphorus fractions dominated in the sediment accounting for 51.4%, while the most abundant form of inorganic phosphorus was Ca-bound phosphorus. The rank order of P fractions was HCl-P > NaOH-P > BD-P > NH4Cl-P > Res-P. The decrease both in the dissolved oxygen level in the lake water and the Fe:P ratio in the lake sediment resulted in the high contribution of the phosphorus fractions to the overlying water.

4

Design and development of a semi-active suspension system for a quarter car model using PI controller

Siswoyo H., Mir-Nasiri N., Ali M. H.

Journal of Automation Mobile Robotics and Intelligent Systems

|

2017

|

Vol. 11, No. 4

26--33

EN

This paper presents the design and development of a semi-active suspension system for a vehicle. The main idea is to develop a system that is able to damp vibration of the vehicle body while crossing the bumps on the road. This system is modeled for a single wheel assembly and then the laboratory prototype of the complete system has been manufactured. It is used to physically simulate the spring-mass-damper system in vehicle and observe the frequency response to the external disturbances. The developed low-cost smart experimental equipment consists of a motor with offset mass which works as an oscillator to induce vibration, a spring-mass-damper system where the variable damper works as a pneumatic cylinder that allows varying the damping constant (c). Proportional-Integral (PI) controller is used to control the damping properties of the semi-active suspension system automatically. The system is designed in contrast to the most of the available suspension systems in the market that have only passive damping properties. The results of this research demonstrate the efficiency of the developed variable damper-based control system for the vehicle suspension system.

5

Hand-arm vibration disorder among grass-cutter workers in Malaysia

Azmir N. A., Ghazali M. I., Yahya M. N., Ali M. H.

International Journal of Occupational Safety and Ergonomics

|

2016

|

Vol. 22, No. 3

433--438

EN

Introduction. Prolonged exposure to hand-transmitted vibration from grass-cutting machines has been associated with increasing occurrences of symptoms and signs of occupational diseases related to hand–arm vibration syndrome (HAVS). Methods. A cross-sectional study was carried out using an adopted HAVS questionnaire on hand–arm vibration exposure and symptoms distributed to 168 male workers from the grass and turf maintenance industry who use hand-held grass-cutting machines as part of their work. The prevalence ratio and symptom correlation to HAVS between high and low–moderate exposure risk groups were evaluated. Results. There were positive HAVS symptoms relationships between the low–moderate exposure group and the high exposure group among hand-held grass-cutting workers. The prevalence ratio was considered high because there were indicators that fingers turned white and felt numb, 3.63, 95% CI [1.41, 9.39] and 4.24, 95% CI [2.18, 8.27], respectively. Less than 14.3% of workers stated that they were aware of the occupational hand–arm vibration, and it seemed to be related to the finger blanching and numbness. Conclusion. The results suggest that HAVS is under-diagnosed in Malaysia, especially in the agricultural sectors. More information related to safety and health awareness programmes for HAVS exposure is required among hand-held grass-cutting workers.