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Synthesis, performance and reaction mechanisms of Ag-modified multi-functional rice husk solvochar for removal of multi-heavy metals and water-borne bacteria from wastewater
No full textThis study introduces a new thermo-chemical conversion technique, solvothermal carbonization on rice husk with alcoholic solvents, ethanol, and isopropanol (IPA) at a low temperature, 280 ℃ with 2 h reaction time to produce innovative char, solvochar. Solvochars were hierarchically activated by potassium hydroxide (KOH), impregnated with silver nanoparticles (AgNPs), and stabilized through the calcination process at high temperatures and residence time. The functionalized solvochar was comprehensively characterized by FTIR, BET-BJH, XRD, XRF and XPS analyses. The maximum surface area, pore diameter and pore volume were obtained, 77.38 m2/g, 18.44 nm and 0.32 cm3/g by IPA-AgNPs. The active units in functionalized solvochars were enhanced surface area-porosity, sp2, and sp3-hybridized aromatic carbon compounds and oxygen-containing alcoholic groups for physio-chemisorption of heavy metal ions. Further, the functionalized solvochars were applied for the adsorption of multi-heavy metal ions, Cu2+, Fe3+, Pb2+, Zn2+, and Mn2+ through fixed-bed flow column adsorption till reaching the saturation stage of two consecutive cycles. The heavy metal ion adsorption uptake for experimented solvochars were ⁓100–230 mg/g Cu2+, ⁓513–569 mg/g Fe3+, ⁓3–9 mg/g Mn2+, ⁓164–190 mg/g Pb2+, ⁓64–100 mg/g Zn2+ for 1st cycle and ⁓2–57 mg/g Cu2+, ⁓6–132 mg/g Fe3+, ⁓3–5 mg/g Mn2+, ⁓3–30 mg/g Pb2+, ⁓2–19 mg/g Zn2+ for 2nd cycle. The adsorption kinetics have been analyzed by intra-particle diffusion (IPD) modelling. Among multi-heavy metal ions, Fe3+ was adsorbed continuously till the saturation stage and R2 was obtained, 0.67–80 through IPD modelling. The post-adsorption characterization of solvochars presented the possibility of recycling. The significant presence of sp3d-hybridized AgNPs in all adsorbents acted as a potent antimicrobial agent against the most common wastewater-relevant bacteria, Escherichia coli, and Staphylococcus aureus. 0.03 wt% loading rate of Ag-functionalized solvochars inhibited both bacteria growths completely. This phenomenon reinforces the potential of the Ag-modified solvochar composites to be applied as potential multi-functional adsorbents for realistic approach
Influence of MHz-order acoustic waves on bacterial suspensions
No full textThe development of alternative techniques to efficiently inactivate bacterial suspensions is crucial to prevent transmission of waterborne illness, particularly when commonly used techniques such as heating, filtration, chlorination, or ultraviolet treatment are not practical or feasible. We examine the effect of MHz-order acoustic wave irradiation in the form of surface acoustic waves (SAWs) on Gram-positive (Escherichia coli) and Gram-negative (Brevibacillus borstelensis and Staphylococcus aureus) bacteria suspended in water droplets. A significant increase in the relative bacterial load reduction of colony-forming units (up to 74%) can be achieved by either increasing (1) the excitation power, or, (2) the acoustic treatment duration, which we attributed to the effect of the acoustic radiation force exerted on the bacteria. Consequently, by increasing the maximum pressure amplitude via a hybrid modulation scheme involving a combination of amplitude and pulse-width modulation, we observe that the bacterial inactivation efficiency can be further increased by approximately 14%. By combining this scalable acoustic-based bacterial inactivation platform with plasma-activated water, a 100% reduction in E. coli is observed in less than 10 mins, therefore demonstrating the potential of the synergistic effects of MHz-order acoustic irradiation and plasma-activated water as an efficient strategy for water decontamination
Advanced Air Mobility: A comparative review of policies from around the world—lessons for Australia
No full textAdvanced Air Mobility (AAM), the use of drones for the delivery of goods and for transport of passengers, is an emerging mode of transportation. However, numerous challenges remain before AAM on a commercial scale will be a reality. AAM forces changes to the current air transportation system and governments globally are tasked with formulating new policies and regulations. In this work, we evaluate AAM policies from four different countries by utilising a case study approach and comparing those to emerging policies in Australia. We found that approaches differ between very comprehensive frameworks to simple, more general regulation. Results also
show that Australia can learn a lot from Dubai’s example. In summary, these findings suggest that AAM policy development globally is in its infancy and provide insights into possible future pathways for AAM policy development in Australia and beyond
The impact of contact and contactless interactions between the meta-atoms on terahertz bound states in the continuum
No full textThe excitation and manipulation of symmetry-protected bound states in the continuum (SP-BIC) is significantly valuable for metasurface-based biosensors. The interactions between adjacent meta-atoms determine the fundamental properties of SP-BIC; however, this topic has not been profoundly explored. In this work, we experimentally and numerically investigate the effects of contactless and contact interactions between adjacent dual-gap split-ring resonators (DSRRs) on the SP-BIC. We demonstrate that there is only one SP-BIC at 0.9 THz when the incident radiation polarization is parallel to the gap in both contactless and contact coupling conditions. When the polarization is vertical to the gap, the individual SP-BIC shifts the frequency to 0.8 THz under contactless coupling. Under contact coupling, the SP-BIC degrades to be an electromagnetically induced transparency (EIT) windows at 0.8 THz. We calculated a 3.6 ps group delay of slow light for EIT. Numerical simulations indicate that the combination of one magnetic dipole (MD) in the inner arm and another electric dipole in the outer arm of DSRR results in quasi-BIC at 0.9 THz and 0.8 THz under contactless coupling. Under contact coupling conditions, the formation of quasi-BIC at 0.9 THz is similar to contactless coupling. However, two MDs of opposite polarity results in the EIT windows at 0.8 THz. Our results reveal excitation and manipulation of terahertz SP-BIC via contactless and contact coupling, which is significant for the innovation of terahertz biosensors
Assessing the Impact of Metrics on the Choice of Prognostic Methodologies
No full textOver the past years, advanced prognostic models and approaches have been developed. Most existing approaches are tailored to one specific system and cannot adaptively be used on different systems. This can lead to years of research and expertise being put into implementing prognostic models without the capacity to predict system failures, either because of a lack of data or data quality or because failure behavior cannot be captured by data-driven models. In addition, prognostic models are often evaluated using metrics only related to the correctness of predictions, preventing meaningful evaluation of operational performance. This paper makes use of a framework that can automatically choose prognostic settings based on specific system data. It simultaneously optimizes the choice of methodologies using metrics that capture multiple aspects of prediction quality. We apply this framework to both a simulated data set and a real aircraft data set to characterize the impact of metrics on the choice of prognostic methodologies. The results show that the choice of optimization metric greatly impacts the output of the generic prognostic framework and the overall performance. In addition, a definition for data suitability is provided and assessed on the aircraft system data sets
Measuring the Effect of Built Environment on Students’ School Trip Method Using Neighborhood Environment Walkability Scale
No full textSchool trips affect different aspects, such as air pollution and urban traffic, and of personal wellbeing, such as students’ physical and mental health. The increasing concern about environmental sustainability has prompted a reevaluation of daily activities, including school transportation. While different factors that affect students’ school trips have been investigated in the literature, the effect of the built environment has been evaluated only sporadically in previous studies. To fulfil this knowledge gap, this study aims to investigate the effect of the built environment on students’ school trips by adapting and extending the well-known Neighborhood Environment Walkability Scale (NEWS) questionnaire. The questionnaire survey was conducted with parents from 36 schools in Yazd, Iran, providing a sample of 1688 students aged 7–18 years. The items from the NEWS questionnaire were placed in nine factors by performing factor analysis. The Multinomial Logit Regression model was applied to check the predictive power of these nine factors. It was found that the variables of land use mix-diversity, land use mix-access, crime, age, gender, household income and car ownership had a significant effect on students’ school trips. The more easily students have access to different places, the less they use public services and cars compared with the active travel mode. The use of public services and cars increases with the increase in crime rate along the route to school. The findings indicate that built environment features may impact students’ shift from traditional transportation modes to active alternatives, such as walking and cycling, contributing to the attainment of broader sustainability objectives
Layout and geometry optimization design for 3D printing of self-supporting structures
No full textAs the demand for high-performance structures in various scenarios continues to rise, the complexity of engineering structures also increases, necessitating the development of advanced design methods and the additive manufacturing (AM) of sophisticated structures. While the layout optimization method based on the ground structure technique can produce optimized designs, the gravity-induced overhang effect during the printing process often requires additional support materials. The use of additional support materials during the printing process can result in higher material costs or the need for post-processing to remove the support structures, significantly hindering the adoption of AM in practice. This paper presents an optimization framework to obtain self-support optimization designs and provides a practical validation for the effectiveness of the proposed framework. Firstly, a self-support point-line structure is obtained via the layout and geometry optimization, considering overhang constraints. Secondly, the point-line structure is transformed into a physical model with nodal expansion considered (i.e., taking into account the overlapping of members at nodes). Finally, the physical models are sliced and printed using both a plastic Fused Deposition Modeling (FDM) printer and a metal Wire Arc Additive Manufacturing (WAAM) printer. The results confirm that the proposed process is effective for both plastic and metal printing, demonstrating its exceptional versatility
The MOFs/COFs-derivant decorating FeSiAl coupling magnetic and electrical losses for enhanced microwave absorption
No full textTraditional single-component microwave absorbers face the difficulties including the narrow absorption bandwidth and low absorption strength. Herein, we develop a novel dual-magnetic composite decorating with covalent-organic framework (COF of 1,3,5-triformylphloroglucinol and p-phenylenediamine: TpPa) and carbon hybrid to enhance microwave absorption performance. Namely, a dual-magnetic FeSiAl@(CoFe2O4/C)@TpPa core–shell structure with rich interfacial polarizations was prepared by the three main steps: firstly, the plate-like FeSiAl was decorated with the MOFs of ZIF-67. And then it was converted to FeSiAl@(CoFe2O4/C) after an annealing process under Ar. Lastly, the in-situ growth of COF (TpPa) was designed for enhanced microwave penetration into the interior of absorbers. The as-design dual-magnetic FeSiAl/CoFe2O4 effectively favors to magnetic domain resonance resulting in the dual-magnetic coupling effects. Meanwhile, the multi-level structure formed by ultra-fine carbon in FeSiAl@(CoFe2O4/C)@TpPa enables magnetic-dielectric synergies and enriches the attenuation path as well. Furthermore, the accumulation of transferred charge at multiple interfaces provides a stronger relaxation polarization loss. The above positive factors collectively promote the high-performance microwave absorption with the reflection loss (RL) value up to −51.3 dB and the effective absorption bandwidth (EAB) covers 3.2–17.7 GHz by adjusting the thickness of absorbers. Therefore, this dual-magnetic/dielectric coupling approach provides an innovative strategy for fabricating advanced microwave absorbers
Altered dietary behaviour during pregnancy impacts systemic metabolic phenotypes
No full textRationale: Evidence suggests consumption of a Mediterranean diet (MD) can positively impact both maternal and offspring health, potentially mediated by a beneficial effect on inflammatory pathways. We aimed to apply metabolic profiling of serum and urine samples to assess differences between women who were stratified into high and low alignment to a MD throughout pregnancy and investigate the relationship of the diet to inflammatory markers. Methods: From the ORIGINS cohort, 51 pregnant women were stratified for persistent high and low alignment to a MD, based on validated MD questionnaires. 1H Nuclear Magnetic Resonance (NMR) spectroscopy was used to investigate the urine and serum metabolite profiles of these women at 36 weeks of pregnancy. The relationship between diet, metabolite profile and inflammatory status was investigated. Results: There were clear differences in both the food choice and metabolic profiles of women who self-reported concordance to a high (HMDA) and low (LMDA) Mediterranean diet, indicating that alignment with the MD was associated with a specific metabolic phenotype during pregnancy. Reduced meat intake and higher vegetable intake in the HMDA group was supported by increased levels of urinary hippurate (p = 0.044) and lower creatine (p = 0.047) levels. Serum concentrations of the NMR spectroscopic inflammatory biomarkers GlycA (p = 0.020) and GlycB (p = 0.016) were significantly lower in the HDMA group and were negatively associated with serum acetate, histidine and isoleucine (p < 0.05) suggesting a greater level of plant-based nutrients in the diet. Serum branched chain and aromatic amino acids were positively associated with the HMDA group while both urinary and serum creatine, urine creatinine and dimethylamine were positively associated with the LMDA group. Conclusion: Metabolic phenotypes of pregnant women who had a high alignment with the MD were significantly different from pregnant women who had a poor alignment with the MD. The
Theoretical prediction on the stability, elastic, electronic and optical properties of MAB-phase M4AlB4 compounds (M = Cr, Mo, W)
No full textThis research employs first-principles calculations to address the challenges presented by processing complexity and low damage tolerance in transition metal borides. The study focuses on designing and investigating MAB phase compounds of M4AlB4 (M = Cr, Mo, W). We conduct a comprehensive assessment of the stability, phononic, electronic, elastic, and optical properties of Cr4AlB4, Mo4AlB4, and W4AlB4. The calculated results reveal formation enthalpies of −0.516, −0.490, and −0.336 eV per atom for Cr4AlB4, Mo4AlB4, and W4AlB4, respectively. Notably, W4AlB4 emerges as a promising precursor material for MABene synthesis, demonstrating exceptional thermal shock resistance. The dielectric constants ϵ1(0) were determined as 126.466, 80.277, and 136.267 for Cr4AlB4, Mo4AlB4, and W4AlB4, respectively. Significantly, W4AlB4 exhibits remarkably high reflectivity (>80%) within the wavelength range of 19.84-23.6 nm, making it an ideal candidate for extreme ultraviolet (EUV) reflective coatings. The insights gleaned from this study provide a strong research framework and theoretical guidance for advancing the synthesis of innovative MAB-phase compounds