Steel slag is a by-product of steelmaking which has emerged as a potential CO₂ sequestration material due to its high reactivity and abundance. This research investigates the use of steel slag waste for the direct capture of carbon from air and its storage through mineral carbonation. Two abundant wastes, blast-furnace slag (BFS) and ladle slag (LS), were tested for their carbon sequestration potential, and the effects of operational parameters such as reaction time between CO₂ and slag waste, temperature, liquid-solid ratio, and pressure on CO₂ sequestration were determined. Quantitative and qualitative results reveal that much higher CO₂ sequestration was achieved using LS compared to BFS after exposure to CO₂ for 1 day at room temperature. By increasing the exposure time to four days, levels of CO₂ sequestration increased gradually from 2.71% to 4.19% and 23.46%-28.21% for BFS and LS respectively. Increasing the temperature from 20 ± 2 °C to 90 ± 2 °C positively influenced CO₂ sequestration in BFS, resulting in an enhancement from 3.45% to 13.21%. However, the impact on LS was insignificant, with sequestration levels rising from 27.72% to 29.90%. Moreover, better CO₂ sequestration was observed for BFS than LS when the liquid-to-solid ratio increased from 3:1 to 4:1, whereupon the sequestration potential reached approximately 15% for BFS and 30% for LS at 90 ± 2 °C. Meanwhile, higher pressure reduced the sequestration potential of slag. The results of this study suggest that there is potential for scaling up the process to industrial applications and contributing to the reduction of CO₂ emissions in the steelmaking industry.

Reliability and mean-time-to-failure (MTTF) of crystalline silicon photovoltaic (c-Si PV) module operating at elevated temperature can be increased through in-depth understanding of the mechanics of thermo-mechanical deformation and degradation of the laminates bonded together in the system. The knowledge is critical to developing the next generation of robust c-Si PV modules. Deployment in elevated ambient temperature reduces the 25-year design life by inducing excessive deformation that results in significant laminate degradation. The research investigates the thermo-mechanical deformation of c-Si PV module. Analytical and simulation methods are employed in the investigation. The IEC 61215 test qualification is used. Ethylene vinyl acetate (EVA) and solder materials responses are modelled as temperature dependent with appropriate material models. Analytical technique for validating simulation results of the response of c-Si PV module to temperature load is presented. The laminate’s stiffness is found to be governed by the stiffness ratio magnitude of silicon which is the most stressed component. The deformation ratio of EVA is highest and significantly determines the degree of variation of gap between solar cells. The EVA exhibits the highest susceptibility to thermo-mechanical deformation followed by the solder which is found to accumulate the highest magnitude of strain energy density. The research presents an analytical method that can be used to validate the output of computer-simulation of the magnitude of strain energy density of solder in c-Si PV modules

This paper presents a case history of a geotextile reinforced highway embankment constructed on a soft estuarine deposit installed with prefabricated vertical drains. The case history documents the geotechnical site characterization, embankment construction, and monitoring program. The loading response of the soft estuarine soil was monitored during construction using hydrostatic profile gauges, settlement plates, pneumatic piezometers, and slope inclinometers. Settlements of up to 1.3 m were measured under the 4 m high embankment. The deformation behaviour was interpreted qualitatively from the monitoring data using the general framework of elastic-plastic soil models. The effectiveness of the monitoring program is also briefly discussed. The paper provides performance details that make this case history useful to researchers studying the loading response of soft soils under a geotextile reinforced embankment.Key words: case history, embankment, soft clay, vertical drainage, reinforcement.

This study utilises response surface methodology (RSM) to optimise the conditions under which CO₂ sequestration occurs during the pioneering use of steel slag in a mineral carbonation process. Crucial factors such as time, reaction temperature, pressure conditions and the liquid/solid ratio are systematically varied and analysed to determine if CO₂ sequestration is efficient. The results show that the amount of carbon captured was directly impacted by the relationship between time and temperature. For instance, when these variables increased from 20 °C to 90 °C and one day to four days respectively, carbon sequestration in ladle slag increased from 101.23 kg to 149.32 kg of CO₂ per tonne, a rise of approximately 48 %. Moreover, carbon sequestration was also enhanced when pressure and the liquid/solid ratio increased, although this effect declined once a certain level was reached. From the application of RSM for 120.46 kg of CO₂ per tonne of steel slag, the ideal reaction conditions were predicted to be 60.83 °C, a reaction time of one day, 15.63 bar pressure and a 90/30 liquid/solid ratio. These predictions were validated through experimentation, which generated a result of 118.03 kg of CO₂ per tonne of steel slag with a relative error of 2.04 %.