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A Predictive Model for Monolayer-Selective Metal-Mediated MoS2 Exfoliation Incorporating Electrostatics
No full textThe metal-mediated exfoliation (MME) method enables monolayer-selective exfoliation of van der Waals (vdW) crystals, improving the efficacy of large monolayer production. Previous physical models explaining monolayer-selective MME propose that the main contributors to monolayer-selectivity are vdW crystal/metal surface binding energy and/or vdW crystal layer strain resulting from lattice mismatch. However, the performance of some metals for MME is inconsistent with these models. Here, a new model is proposed using MoS2 as a representative vdW crystal. The model explains how the MoS2/metal interface electrostatics, in combination with strain, determines monolayer-selectivity of MME by modulating the MoS2 interlayer energy. Monolayer MoS2/metal interfaces are characterized using in situ Raman spectroscopy and density functional theory calculations to estimate the electrostatics and strain of MoS2 in contact with different metals. The model successfully demonstrates the dependence of MME monolayer-selectivity on the MoS2/metal interface electrostatics and highlights the significance of electrostatics in nanomaterial vdW interactions
Unravelling the atomistic-scale insights into tensile response of equiatomic cupronickel alloy with pre-existing faceted grain boundary interface
No full textThe aim of this research work is to investigate the effect of strain rates and temperatures on the mechanical properties of an equiatomic copper-nickel (Cu–Ni) alloy with a pre-existing faceted Σ3 [111] 60° {11 8 5} grain boundary. Molecular dynamics simulations conducted in this scrutiny focuses on understanding the tensile behaviour of bicrystalline equiatomic Cu–Ni alloys (denoted by Cu50Ni50) under various thermodynamic conditions. The uniaxial tensile deformation simulation was carried out at various strain rates (108, 109 and 1010 1/s) in conjunction with different conditions of cryogenic temperature (100 K), room temperature (300 K) and high temperature (500 K). The authors found that the yield stress and Young's modulus of the bicrystalline Cu50Ni50 alloy were highest at the cryogenic temperature, and decreased as the temperature increased. To add on, the yield stress of the bicrystalline Cu50Ni50 alloy increased with an increase in the strain rate value. From the microstructural and dislocation analysis point of view, it was observed that the formation of dislocations was lowest at the cryogenic temperature. Interestingly, at the yield point, the coherent twin boundary tip act as the nucleation site for the dislocations for cryogenic temperature condition. These findings shed light on the relationship between the temperatures, strain rates, and the mechanical properties of Cu–Ni alloys, which will aid in reporting the optimized conditions for their desired engineering applications. It is also proposed that tailoring of the tensile properties is achievable by exposing Cu–Ni alloys to various environmental conditions (cryogenic, ambient, and elevated temperatures with different applied strain rates)
Understanding knowledge leadership in improving team outcomes in the health sector: a Covid-19 study
No full textPurpose: This study seeks to examine the role of knowledge-oriented leadership in the health sector to achieve team outcomes in the Covid-19 context. Drawing from the leader–member exchange (LMX), social cognitive and social identity theory, the present study develops a model linking knowledge-oriented leadership and team performance through the underlying psychological mechanisms of team efficacy, team cohesion, team commitment and team collaboration. Design/methodology/approach: Utilizing quantitative data methodology, data were obtained from the pharmaceutical employees (health sector) of Pakistan during the pandemic. The partial least squares structural equation modeling was used to test the hypotheses. Findings: The findings support the hypothesis that knowledge-oriented leadership significantly influences team outcomes. The study also verified that team collaboration effectively mediates the relationship between knowledge-oriented leadership and team performance. Originality/value: The study is unique in the sense that it explores the newly established leader behavior (knowledge-oriented leadership) in understanding team outcomes in the health sector. The study concludes by making significant implications to overcome the challenges raised by Covid-19 pandemic
Silica supported biosynthesized silver nanoparticles as effective adsorbent and photocatalyst for removal of methylene blue from water
No full textThe silica supported silver nanoparticles (Ag@SG) were prepared by wet impregnation of silica gel (SG) using different concentrations of biogenic silver nanoparticles (AgNPs; 0.25–5 mM) solution, prepared from Cicer arientinum pod extract. Among them, the Ag@SG composite prepared by using 1.25 mM AgNPs solution (Ag1.25@SG) was found to contain only Ag0 species as nanoparticles, whereas the samples prepared by higher concentrations contained Ag0 as well as Ag+ (silver oxide) species. All the Ag@SG composites including SG, exhibited good adsorption capacity for a cationic dye (methylene blue; MB) in water. However, Ag1.25@SG having only Ag0 species exhibited higher photocatalytic activity for degradation of MB under visible light irradiation as compared to other composites. The study reveals that the plasmonic Ag0 species supported on silica are catalytically more active than Ag+ species. Furthermore, the AgNPs (Ag0) in supported form exhibits much higher (∼5-fold) photocatalytic activity than unsupported AgNPs. The synergistic effect of adsorption property of silica surface and plasmonic photocatalytic activity of AgNPs in the synthesized composites was found to be effective for the removal of MB. In addition, the fine dispersion of AgNPs on internal surface of silica provides better activity for photocatalysis. The study shows that this material is a promising adsorbent as well as photocatalyst for the removal of dyes from water
Effect of Protein Content on Heat Stability of Reconstituted Milk Protein Concentrate under Controlled Shearing
No full textMilk protein concentrates (MPCs) possess significant potential for diverse applications in the food industry. However, their heat stability may be a limitation to achieving optimal functional performance. Shearing, an inherent process in food manufacturing, can also influence the functionality of proteins. The aim of this research was to examine the heat stability of reconstituted MPCs prepared at two protein concentrations (4% and 8% w/w protein) when subjected to varying levels of shearing (100, 1000, or 1500 s−1) during heating at 90 °C for 5 min or 121 °C for 2.6 min. While the impact of shear was relatively minor at 4% protein, it was more pronounced in 8% protein MPC suspensions, leading to a considerable decline in heat stability. An increase in protein concentration to 8% amplified protein interactions, intensified by shearing. This, in turn, resulted in comparatively higher aggregation at elevated temperatures and subsequently reduced the heat stability of the reconstituted MPCs
Performance investigation and evaluation of a low-temperature solar thermal energy storage system under dynamic weather conditions
No full textDesigned and operational parameters matter greatly in how successful an energy storage system performs. However, a current challenge in matching suitable these parameters lies in the poor understanding of such systems’ performance under dynamic weather conditions. In this paper, we investigated a phase change material (PCM) storage unit that is particularly aimed for poor-solar areas, and connected the unit to a flat plate solar collector to establish a complete solar thermal energy storage system (STESS). To optimize the system performance, different grades of solar radiation and outdoor ambient temperatures are introduced, and the effects of heat transfer fluid (HTF) flow rates and solar collecting areas are investigated numerically through multiple performance evaluation parameters. The results indicate that the solar collecting area has a significant effect on the performance of the STESS compared to that of the water flow rate. And different collecting areas of 1 m2, 1.5 m2, and 3 m2 with an optimal water flow rate of 0.06 m3/h are matched to different average daily solar radiation of 203.4 W/m2, 155.2 W/m2, 92.7 W/m2, respectively. Further for the heat release process, different heat release efficiencies from 88.32 % to 97.12 % with different energy consumption of the fan from 0.003 kWh to 0.063 kWh are obtained when the air flow rate is increased from 30 m3/h to 90 m3/h. One of the air flow rates of 60 m3/h is superior for the STESS considering higher heat release efficiency and lower energy consumption of the fan. The findings of this paper will contribute to optimizing the performance of a STESS in practical applications
Diffusive transport phenomena of lactoferrin from gelatin gels crosslinked with genipin
No full textIn order to examine the effects of crosslinking and structure on the swelling and diffusive phenomena in a hydrogel, low-solid gelatin gels were crosslinked with a range of genipin proportions. The ninhydrin assay showed high levels of successful crosslinking within the gels whilst FTIR and WAXD showed successful entrapment of the bioactive molecule lactoferrin within the matrix. Rheological analysis further assessed the effects of crosslinking on the system with an increase in network strength at greater genipin additions. SEM illustrated the successful incorporation of lactoferrin and how the pronounced changes in gel morphology influences entrapment. Experimental evidence supported theoretical estimations of the gel morphology using the Flory-Rehner theory. Analysis of the diffusive transport of lactoferrin from each crosslinked system suggested that densely bound matrices hinder the free movement of molecules. Pairing aspects of the Flory-Rehner theory with the diffusion data allowed for the calculation of the critical molecular weight between crosslinks (M*c) for diffusion to occur and the coupling parameter (ξ) for the gelatin and lactoferrin chain segments
Visibility and invisibility in the aged care sector: Visual representation in Australian news from 2018–2021
No full textThe skyrocketing number and severity of issues in Australian aged care led to the establishment of the Royal Commission into Aged Care Quality and Safety in 2018. Yet, compared to other Royal Commissions, media coverage has been relatively muted, and public awareness and engagement with aged care issues has been uneven. Journalists bear a significant responsibility for shaping the national conversation about aged care, and ensuring this demographic is reflected in the news Australians consume. Due to their unique properties, images are especially important in giving visibility to this historically marginalised topic, and to emotionally engaging an often apathetic public. As such, this study focuses on the aged care visuals accompanying Australian news coverage during the period of the Royal Commission's announcement through to four weeks after the government's response. Drawing on the lens of symbolic annihilation, it does this through a visual analysis that examines who or what is represented and the role of news values in shaping the selection of images included with news reports over this period
Liquid waste management in the construction sector: a systematic literature review
No full textLiquid waste from construction sites can cause significant negative social, economic and environmental impacts. Generally, liquid waste from construction-related trades’ activities, such as product mixing, application and tool washing; stormwater run-off; and leaching of construction material, can pollute surface soil, water bodies and groundwater sources. Therefore, construction projects must have proper management of construction-related liquid waste. This study therefore undertook a systematic literature review (SLR) to analyse the literature on liquid waste management in construction projects. The study used the PRISMA (preferred reporting items for systematic reviews and meta-analyses (method)) framework, and the bibliometric tool, VOSviewer, to analyse and present its findings. The SLR process identified and analysed 49 papers, published between 1992 and 2022, and found that liquid waste management was an often-overlooked area within the construction sector. The review identified three liquid waste focus areas: sources and composition of construction liquid waste; construction liquid waste control methods; and construction liquid waste management. The study’s findings identified a lack of integration between research on liquid waste management and research studies on construction site water pollution. The study’s contribution highlights the current progress of construction liquid waste management research and identifies the need for future research on efficient and effective implementation of liquid waste management practices in construction projects
Care theft: Family impacts of employer control in Australia’s retail industry
No full textPaid work promises pathways to financial security and wellbeing for families, yet variable scheduling and low pay can interfere with the routines and rhythms of family life, and contribute to caregiving challenges and stress. Using qualitative data from a survey of retail workers, this article shows how Australian employment policies have enabled flexibility practices to be strongly oriented around the needs of employers, reducing employees' resources for care. We develop the concept of 'care theft' from employees' accounts of the ways flexible scheduling and low pay converge to transform and deplete their temporal, financial and ethical resources for care. As an extension of 'time theft' and alternative to individualised notions of 'work-family balance', care theft helps make visible the ways employment practices strip resources for care from working people, and shift risk to low-income families and communities