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Barnacle-rich facies as a tool for palaeoenvironmental reconstructions
No full textPalaeoenvironmental data are fundamental in determining the manifold impacts of climate change. This paper argues that sessile barnacles are an excellent palaeoenvironmental proxy: they are present in nearly all nearshore environments, and their shell consists of diagenetically stable low-magnesium calcite and grows fast enough to record short-term variations. To demonstrate their utility, specimens from several Western Mediterranean Pliocene and Pleistocene barnacle-rich deposits are analysed herein, using for the first time a combination of sedimentology, taphonomy, stable isotope geochemistry and detailed comparisons with modern counterparts. Within shelf carbonate systems, barnacle diversity is highest in the shallow, nearshore waters and decreases moving offshore, thus providing a good proxy for the reconstruction of water depth and distance from the coastline. Barnacle taphonomy is also informative. Well-preserved complete specimens are characteristic of protected areas, whereas less well-preserved specimens occur in high-energy areas. The presence/absence of opercular plates is also particularly relevant for evaluating hydrodynamic conditions. As regards the C and O stable isotope ratios, due to the porous and coarse-grained nature of the deposits in which barnacle remains are usually found, the shells are often exposed to meteoric water percolation during diagenesis. Among the analysed specimens, only those collected from fine-grained deposits display no evidence of alteration and have isotopic ratios in line with those of their modern counterparts. These fossils display intra-shell variations that in modern barnacles have been related to short-term environmental changes (e.g., seasonal cycles). These results demonstrate that barnacles can always be useful for detailed palaeoenvironmental reconstructions based on skeletal assemblages. Furthermore, with further research aimed at gathering more data and assessing potentially interfering signals, they could become useful proxies for palaeoseasonality
Adsorption-solubilization controlled extraction of pyrene from surfactant solutions by graphene oxide
No full textGraphene and its derivatives such as graphene oxide (GO) has attracted increasing attention in water treatment because of its unique physical and chemical properties. Herein, the adsorption performance of GO for a typical polycyclic aromatic hydrocarbon (PAH), pyrene from solutions of either a non-ionic surfactant Tergitol 15-S-7 or an anionic surfactant sodium dodecyl benzene sulphonate (SDBS) is investigated. It demonstrates that the high affinity of GO to pyrene leads to multi-layer adsorption of pyrene, with an adsorption capacity 2 to 3 times of its own weight at a low GO concentration of 3.9 mg/L. Linear two-zone pyrene adsorption isotherms are identified, which should be due to competitive adsorption-solubilization processes of pyrene. Although Tergitol 15-S-7 has a considerably higher solubilization capacity (affinity) for pyrene compared to SDBS, faster adsorption kinetics, larger solid-liquid distribution coefficients, and higher recovery of pyrene from Tergitol 15-S-7 solutions are achieved. The higher affinity of SDBS to GO leads to its competitive adsorption that impairs the adsorption of pyrene by GO. Furthermore, the GO demonstrates excellent adsorption capacity for pyrene even after 5 recycling cycles
Study on the excitation effect and mechanism of coal gasification slag based on solid waste
No full textCoal gasification slag (CGS) has pozzolanic activity, and it could be used as a supplementary cementitious material after be activated by some solid waste, which will promote resource utilization of solid waste. In this paper, coal calcium carbide slag and desulfurization gypsum were chosen to activate CGS, the excitation effects were evaluated in different ways and compared with those of salt activators. The microscopic were measured by thermal gravimetry (TG), scanning electron microscopy (SEM) and X-ray diffractometer (XRD) to analyze the excitation mechanism of CGS. The results show that the excitation effects of calcium carbide slag and desulfurization gypsum on CGS are superior to those of salt activators; Through microscopic analysis, the activator promotes the dissolution of glassy state in CGS, accelerates the disaggregation of network structures such as silicon and oxygen, enhancing the activity of CGS. The results of this study can provide references for the excitation of CGS
Towards Sustainable Trust: A Practical SGX Aided Anonymous Reputation System
No full textReputation systems are widely used to provide a trustworthy environment and improve the sustainability of online discussions. They help users understand and evaluate the quality of information by collecting and counting feedback from different users. However, a common issue in most reputation systems is how to maintain users' reputation and protect their anonymity simultaneously. In this paper, we introduce a new practical anonymous reputation system based on SGX. The establishment of an anonymous reputation system has a positive effect on sustainable trust in reputation-based online applications. Our system achieves the combination of reputation and anonymity by utilizing Intel SGX and the Bloom filter. The Path ORAM algorithm is also implemented to resist side-channel attacks. The experiments demonstrate that our system achieves high performance in terms of computation and storage costs. When compared to two state-of-the-art anonymous reputation systems, our system has better computation performance with at least three orders of magnitude
Fat, oil and grease wastewater and dishwashers: Uncovering the link to FOG deposition
No full textFats, oils, and grease (FOG) in wastewater generated by commercial food establishments can cause severe environmental damage if not adequately treated. Grease interceptors (GIs) are an effective solution to limit FOG disposal into the sewer, but their efficiency greatly depends on the wastewater's characteristics. This laboratory study examined the physical and chemical properties of synthetic FOG wastewater from handwashing sinks and dishwashers using cooked animal fats and oils, some food solids and the same amount of detergent to explore the impact of dishwashers on key FOG components that contribute to FOG depositions. Results showed that dishwasher-generated wastewater had a significant influence on fatty acid (FA) transformations, particularly in producing very long chain saturated FAs. Relative proportions of FAs revealed a considerable proportion of very long chain FAs, such as palmitoleic (C16:1), linoleic (C18:2), α-linolenic (C18:3), arachidic (C20:0), paullinic (C20:1), behenic (C22:0), erucic (C22:1), lignoceric (C24:0) and nervonic (C24:1), among which most were not highlighted in the real field FOG wastewater. These FAs may play a significant role in FOG solidification if not sufficiently removed before disposal to sewer. The study also found that dishwashers were able to break down FOG particles, creating smaller particles (75 % being ≤68.8 μm and 50 % being ≤7 μm), while handwashing sinks produced larger particles (50 % being ≤118 μm and 10 % being ≤7 μm and). Samples containing cooked animal fats were more likely to be fragmented into smaller sizes than cooking oils due to the impact of the dishwasher. Confocal microscopy analysis results were consistent with the particle sizes measured by laser diffraction. These distinct properties could serve as criteria for updating GI designs, limiting the amount of FOG and FAs disposed of in the sewer system and controlling solidification and blockages, which pose significant threats to the environment
Robust and efficient non-singular boundary element method for scattering and vibration with elastic waves
No full textThe propagation and scattering phenomena of linear elastic waves are often very complex. A robust and efficient numerical tool is required to study such dynamic linear wave phenomena. In this work, a fully three dimensional desingularized boundary element method is presented. Special chosen singular integrals are subtracted from the original integrals, thereby eliminating their (hyper) singular behavior. Validation of the numerical results is done with known analytical results. Then several examples on scattering and manipulation of linear elastic waves are shown for a phased array of vibrating pillars and for waves scattering on a rigid bowl
Environmentally relevant concentrations of chemically complex shale gas wastewater led to reduced fitness of water fleas (Daphnia carinata): Multiple lines of evidence approach
No full textShale gas hydraulic fracturing generates flowback waters that pose a threat to aquatic organisms if released into the environment. In order to prevent adverse effects on aquatic ecosystems, multiple lines of evidence are needed to guide better decisions and management actions. This study employed a multi-disciplinary approach, combining direct toxicity assessment (DTA) on the water flea Daphnia carinata and LC-MS metabolomics analysis to determine the impact of a major ion salinity control (SC) and a cumulative flowback shale gas wastewater (SGW) from a well in the Beetaloo Sub-basin, Northern Territory, Australia. The exposures included a culture water control, simply further referred to as ‘control’, SC at 1% and 2% (v/v) and SGW at 0.125, 0.25, 0.5, 1% and 2% (v/v). The results showed that reproduction was significantly increased at SGW 0.5%, and significantly decreased when exposed to SC 2%. SGW 2% was found to be acutely toxic for the D. carinata (< 48-h). Second generation (F1) of D. carinata exposed to 0.125–1% SGW generally saw reduced activity in four oxidative biomarkers: glutathione S-transferase, lipid peroxidation, reactive oxygen species, and superoxide dismutase. At the metabolomics level, we observed significant changes in 103 metabolites in Daphnia exposed to both SGW and elevated salinity, in comparison to the control group. These changes indicate a range of metabolic disturbances induced by SGW and salinity, such as lipid metabolism, amino acid metabolism, nucleotide synthesis, energy production, and the biosynthesis of crucial molecules like hormones and pigments. These multiple lines of evidence approach not only highlights the complexities of SGW's impact on aquatic ecosystems but also underscores the importance of informed decision-making and management practices to safeguard the environment and its inhabitants
A modular continuous robot constructed by Miura-derived origami tubes
No full textFolding a flat sheet under a specific crease pattern can form a three-dimensional origami tube, which has been proven to exhibit unique mechanical properties and has wide engineering applications. In this study, a novel Miura-derived origami tube is designed, and its precise circular closing condition and mechanical properties are systematically analyzed, revealing that the proposed origami tube has programmable stiffness characteristics. Polyvinyl chloride (PVC) sheet enables the origami tube to have the characteristics of flexibility, bending, compression, and torsion resistance. Then, a modular design strategy for the novel continuous robot constructed with the Miura-derived origami tube as the backbone is proposed. A continuous robot with three origami tube modules in series is designed and fabricated as a representative case. Three steel wires drive each module to achieve independent contraction or bending movement. The unified installation of steel wire-driven motors on the base endows the robot with a lightweight, interconnected inner space, high scalability, and flexibility backbone. The kinematic relationships among the driving space, configuration space, and task space are investigated by geometric model and constant curvature assumption, with the circular trajectory tracking and reachable workspace revealed by numerical simulations. Further, the kinematic decoupling or the multi-driving model based on the stiffness difference of the origami tube between multi-segments is discussed. Finally, three prototype experiments demonstrate both the rationality of introducing origami tubes to design the continuous robot and the application potential
Lysozyme aggregation and unfolding in ionic liquid solvents: Insights from small angle X-ray scattering and high throughput screening
No full textUnderstanding protein behaviour is crucial for developing functional solvent systems. Ionic liquids (ILs) are designer salts with versatile ion combinations, where some suppress unfavourable protein behaviour. This work utilizes small angle X-ray scattering (SAXS) to investigate the size and shape changes of model protein hen egg white lysozyme (HEWL) in 137 IL and salt solutions. Guinier, Kratky, and pair distance distribution analysis were used to evaluate the protein size, shape, and aggregation changes in these solvents. At low IL and salt concentration (1 mol%), HEWL remained monodispersed and globular. Most ILs increased HEWL size compared to buffer, while the nitrate and mesylate anions induced the most significant size increases. IL cation branching, hydroxyl groups, and longer alkyl chains counteracted this size increase. Common salts exhibited specific ion effects, while the IL effect varied with concentration due to complex ion-pairing. Protein aggregation and unfolding occurred at 10 mol% IL, altering the protein shape, especially for ILs with multiple alkyl chains on the cation, or with a mesylate/nitrate anion. This study highlights the usefulness of adopting a high-throughput SAXS strategy for understanding IL effects on protein behaviour and provides insights on controlling protein aggregation and unfolding with ILs
Journey mapping long COVID: Agency and social support for long-hauling
No full textLong COVID, also known as Post COVID-19 condition, is defined by the WHO as the continuation or development of new symptoms three months after the initial SARS-CoV-2 infection, with these symptoms lasting for at least two months with no other explanation. Despite many studies examining the causes and mechanisms of this disease, fewer studies have sought to understand the experience of those suffering from long COVID, or “long-haulers,” This study contributes to the understanding of long-haulers (N = 14) by examining the role of agency and social support in shaping their journeys with long COVID. Drawing on a combination of interviews, questionnaires, and video diaries over a three-month period, journey mapping was used to document the participants' experiences, including symptoms, coping strategies, and lifestyle changes. Analysis of these journey maps resulted in a framework with four clusters demonstrating the importance of social support and patient agency shaping participants’ Long COVID trajectory; the study contributes valuable insights into the daily lives and challenges individuals face with long COVID, informing the development of targeted support programs