ORCID Profile
0000-0002-3108-0467
Current Organisations
Hong Kong University of Science and Technology
,
Swinburne University of Technology
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Publisher: Springer Science and Business Media LLC
Date: 14-12-2019
Publisher: Springer International Publishing
Date: 2019
Publisher: MDPI AG
Date: 02-01-2020
DOI: 10.3390/MET10010078
Abstract: Ferrous-calcium-silicate (commonly known as FCS) slags are used in the valuable metal recycling from urban ores through both primary and secondary copper smelting processes. In the present study, the structure of selected FCS-MgO (FCSM) and FCS-MgO-Cu2O-PdO (FCSM-Cu2O-PdO) slags, relevant to the processes, were investigated using Fourier-transform infrared (FTIR) spectrometry. Deconvolution of the FTIR spectra was carried out to calculate the relative abundance of different silicate structural units (Qn), the overall degree of polymerization (DOP) of the slags and the oxygen speciation in the FCS slags. It was observed that, for the slag investigated, the relative intensity of both the high-frequency band ≈ 1100 cm−1 (Q3) and low-frequency band ≈ 850 cm−1 (Q0) were affected by Fe/SiO2 ratio, basicity, temperature (T) and oxygen partial pressure (pO2). The DOP and the average number of bridging oxygen (BO) were found to decrease with increasing both Fe/SiO2 ratio and basicity. Improved semi-empirical equations were developed to relate the DOP of the slags with chemistry, process parameters and partitioning ratio (i.e., the ratio of the amount of element in the slag phase to metal phase, also known as distribution ratio) of Pd and Ge. Possible reactions, expressed as reactions between metal cations and silicate species, as a way to evaluate thermodynamic properties, are presented herein.
Publisher: ASTM International
Date: 31-05-2013
DOI: 10.1520/MPC20130001
Publisher: Springer Science and Business Media LLC
Date: 02-04-2020
Publisher: Springer International Publishing
Date: 2020
Publisher: Elsevier BV
Date: 10-2022
Publisher: Springer Science and Business Media LLC
Date: 28-11-2020
Publisher: MDPI AG
Date: 20-05-2022
Abstract: Steel products are coated with Aluminum (Al) and Zinc (Zn) alloys to improve their corrosion properties. Bulk steel products are coated in batches however, steel sheets are coated by a continuous hot-dip galvanizing process. Steel sheets are guided into and out of the molten Al-Zn-Si (AZ) bath with the help of stainless-steel rolls, known as guiding, and sink rolls. These rolls are subjected to excessive surface corrosion with molten AZ bath and, hence, are replaced frequently. The surface deterioration of the immersed rolls has been a long-standing issue in the galvanizing industry. In this study, 316L stainless-steel (SS) rods are immersed in the AZ alloy at 600 °C. The immersion time varied from 1 day to 7 days under the static melt conditions in the iron (Fe)-saturated AZ bath. Microstructural analysis of the immersed SS s les revealed two distinct intermetallic compound (IMC) layers forming between the SS substrate and AZ alloy. The IMC layer 1 (AL-1) formed between the SS substrate and IMC layer 2 (AL-2), growing in thickness from 68 µm to 120 µm within 5 days of immersion. The AL-2, which formed between AL-1 and AZ alloy after 24 h of immersion, then grew in thickness up to 150 µm with an uneven trend. The AL-1 is composed of Fe2Al5 and that of AL-2 is composed of FeAl3 that were predicted by the FactSage thermodynamic analysis. Crack development between AL-1 and AL-2 layers, and disintegration of AL-2 into the AZ bath, are key findings of this study. A drastic hardness increase was observed because the IMC layers produce a hard and brittle sink roll surface.
Publisher: Informing Science Institute
Date: 2020
DOI: 10.28945/4625
Abstract: Aim/Purpose: ICT integration into classroom pedagogical practices is considered an essential aspect of learning processes in developed countries but there are issues in developing countries regarding funding, infrastructure, access, and teacher skills and professional learning. This article presents some aspects of the findings of a study in one remote region within a developing country after the implementation of a widescale ICT initiative. This study investigates issues for implementing ICT in schools in relation to teacher and school leader attitudes, access and ICT use, and improvements needed in Papua which is one of the most remote regions of Indonesia. The paper frames these issues within the context of successful online learning initiatives in developing countries and foreign aid implementation literature, with these aspects being under-researched, especially in significantly remote developing country locations. Background: Developing countries like Indonesia have progressively introduced online learning into school management and classrooms within government planning frameworks and with initial support from foreign aid providers. While there is research available regarding ICT implementation in more urbanized contexts within developing countries, there is a gap in terms of large-scale research which is focused on more remote regions and is supported by foreign aid. Methodology: Mixed methods including surveys and interviews were used to investigate research questions concerning teachers’ and principals’ attitudes, ICT access and use, and perceptions about improvements needed. SPSS software was used for surveys and descriptive analysis, and interviews were analysed through manual coding processes. Contribution: ICT access and e-learning in schools are increasingly becoming relevant in developing country contexts, and this research paper is a preliminary large-scale study that makes a contribution through highlighting issues experienced in more remote locations. This includes specific internet and power issues and transport inaccessibility problems, which highlight the need for locally-based and ongoing coaching of teachers within schools and regions. The paper also draws on the literature about online learning in developing countries and foreign aid towards some possible success directions in isolated contexts, an under-researched area. The importance of education systems establishing ICT skills levels for students integrated across subjects, for well-coordinated planning involving partnerships with hardware and internet providers, as well as the need for school leaders being trained in establishing teacher peer support groups for ongoing coaching, are learnings for Papua and other remote locations from the comparative developing countries literature Findings: The findings highlight teachers’ and school leaders’ positive attitudes to ICT in education, although the results indicate that ICT was frequently applied for administrative purposes rather than for teaching and learning. Principals and teachers highlighted some improvements that were needed including systematic training in computer skills and professional learning about the integration of ICT with teaching and learning, especially in relation to pedagogical practices, as well as the need for improved infrastructure and equipment. Recommendations for Practitioners: The study highlights issues and potential success factors as evident in remote regions of developing countries that have achieved recognition for widescale ICT implementation in schools. This includes issues in relation to policy makers and education authorities working with foreign aid funders. Of significant importance is the need for coordinated and collaborative strategic planning including in relation to sustained professional learning towards student-oriented ICT pedagogies and skilling principals to establish a positive culture and teacher peer coaching. Particularly relevant to developing countries in remote locations is the importance of additionally addressing specific infrastructure and maintenance issues. Recommendation for Researchers: Regarding ICT and its use for student learning, more research is needed in developing countries and, in particular, in more remote locations where specific issues, differing from those encountered in capital cities, may be evident for teachers and principals. Impact on Society: Teachers and principals in remote locations of Indonesia such as Papua have generally positive attitudes about the benefits of online learning but need greater ICT access for students in the classroom and also professional development regarding pedagogical practices to support students in learning effectively through online processes. Future Research: Updated and more detailed comparative research with other developing countries, especially those with remote locations, would be beneficial to more comprehensively identify Papua’s current stage of development and to design appropriate future interventions.
Publisher: Springer Science and Business Media LLC
Date: 29-07-2022
DOI: 10.1007/S11663-022-02593-4
Abstract: Electronic waste (E-waste) is considered as a hazardous material, however, it also contains valuable elements, including gallium (Ga). E-waste can be processed through the black copper smelting to recover these valuable elements. However, the detailed thermodynamics behavior of many of the valuable elements during black copper smelting has not been studied comprehensively. This study aims to investigate the thermodynamics of Ga in copper and slag at black copper smelting conditions. High-temperature equilibrium experiments were carried out to measure the distribution ratio of Ga in Fe 2 O 3 –CaO–SiO 2 slag and copper at temperature range of 1300 °C to 1450 °C (1573 K to 1723 K) and partial pressure of oxygen ( p O2 ) of 10 –6 to 10 –11 atm. The effect of Fe T /SiO 2 ratio and basicity (measured as CaO/SiO 2 ) of the slag on the distribution ratio of Ga were also investigated. The partitioning of Ga into the copper phase was found to increase with decreasing oxygen partial pressure, and with increasing temperature, Fe T /SiO 2 ratio and basicity. The study revealed that a basic slag at higher temperature and at a reducing atmosphere was favorable to increase Ga partitioning to the copper.
No related grants have been discovered for Mohammad Mehedi Hasan.