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Effect of biochar on microplastics penetration treatment within soil porous medium under the wetting-drying cycles and optimisation of soil-biochar mixing format
No full textPlant-based biochar was demonstrated promising capability in adsorbing microplastic particles (MPs) within soil porous mediums. However, biochar’s function in mitigating MPs’ vertical penetration during wetting-drying cycles, typical of seasonal precipitation and evaporation, remains uncertain. Furthermore, few studies have investigated the structures of how biochar combines with soil. This study conducted column tests to assess the MPs retention capabilities of soil-biochar porous media under saturated and wetting-drying conditions. The water retention and hydrophilic properties were investigated to elucidate the impact of wetting-drying cycles. Additionally, different biochar-soil structures were compared to optimise the structural design. Without biochar, wetting-drying cycles resulted in 8.74% more MPs escaping from samples. However, incorporating 15% biochar led to only around 2% more MPs in effluent. Biochar significantly enhanced soil's MP absorption capacity and mitigated the negative effects of wetting-drying cycles. Biochar’s alveolate morphology provides ample adsorption sites and creates complex flow paths. The hydrophilic groups of biochar and capillarity by micropores facilitated slower water release during drying, preventing crack propagation and flush on MP particles. This effect was more pronounced with higher biochar content and lower porosity. Moreover, layer structure was found to improve MPs removal, benefiting the long-term performance and management of the biochar functional layer
“I still struggle to ensure that I am truly listening.” Understanding gender, sexuality, and sexual violence during the Holocaust. A conversation
No full textPerformance of an EBR CFRP-strengthened RC slab using 24-h and cyclic load tests : a real case study
No full textThis study investigates the performance of a case study reinforced concrete (RC) slab strengthened in flexure with Fibre Reinforced Polymer (FRP) sheets. The RC slab is at the top floor of a 17-storey building upon which three water tanks (of 1,000 l each) had to be built due to a change of use of the building's top floor. To assess the performance of the existing slab, site investigations and non-destructive testing (NDT) were carried out as per ACI 318 standards. To increase the load capacity of the slab, Externally Bonded Reinforcement (EBR) Carbon FRP sheets were bonded to the bottom of the RC slab. Following the strengthening intervention, the CFRP-strengthened slab was subjected to a 24-h load test (according to ACI 318) and to a Cyclic Load Test (following ACI 437) using an ad-hoc water pool built on top of the slab. The results from these tests (maximum and residual deflections of 0.92 mm and 0.34 mm, respectively) indicated that the CFRP-strengthened slab met satisfactorily the deflection criteria and performance indices of such tests. The CFRP-strengthened slab was then modelled and analysed in ANSYS® to calibrate and validate the experimental results. It is shown that the deflection and strains predicted by the finite element (FE) model match well the experimental measurements (errors < 15%), which confirms the suitability of the modelling approach adopted in ANSYS®. This article contributes towards the dissemination of real case studies of FRP-strengthened structures, which are scarce in the literature and thus can be useful to engineers and practitioners working in the field of structural strengthening
Rethinking energy geopolitics : towards a geopolitical economy of global energy transformation
Full text linkWe are in the midst of a global energy system transformation (GEST) which is rewiring the world economy, opening new axes of political contestation, and revolutionising the energetic basis of human civilisation. Energy geopolitics has not yet reconciled itself to this challenge. The field has traditionally been preoccupied with the dependence of Western states on cross-border flows of fossil fuels. More recently, efforts have been made to prospectively map out what the geopolitics of a fully renewable world might look like. What both literatures miss, however, is the very fact of the GEST: that we are living through a changing and contested process of global transformation, across interacting high- and low-emissions systems, whose contours are open and actively constructed over time. In this paper, we start to develop a provisional framework to make sense of the GEST, that is able to capture the full scale of the transformation, and its dynamic, contingent, constructed nature. We attend to three areas of geopolitical economy: the wide-ranging material dimensions of the transformation, its geographical space-making, and its conflict-ridden political economy. We then apply this framework to two case studies, one looking at the fraught role of fossil gas as a ‘transition fuel’, the other at lithium-ion batteries
Sensitisation instructions can reduce the misinformation effect and improve the eyewitness confidence-accuracy relationship
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A semi-analytic method for buoyancy-induced thermal stratification in hot water tanks during standby periods
No full textBuoyancy-induced thermal stratification is a spontaneous phenomenon arising from standby periods of hot water tanks. Accurate estimation of temperature levels is crucial for energy-efficient operations of hot water tanks and associated water heating systems. However, temperature estimation by numerical schemes requires sophisticated algorithms and considerable computation resources. This study proposes a novel semi-analytic method to address buoyancy-induced thermal stratification conveniently without iterative calculations. An explicit water temperature function to tank height and time is analytically derived from the modified energy balance equation where the heat convection term is disregarded. The convection effect is compensated for by artificial enhancement of heat conduction, which is indicated by a synthetic parameter, amplification factor. A comprehensive numerical study is carried out to investigate static and transient characteristics of buoyant flows and temperature distribution in a hot water tank during standby periods. The findings imply a strong analogy between buoyancy-induced thermal stratification and a bottom-initiated heat conduction process, which reinforces the physical rationale for the semi-analytic method. The experimental verification of the semi-analytic method is conducted against published experiment data, the proposed method shows excellent estimation accuracy with the rooted mean square error of less than 0.42 °C. Furthermore, suitable case-specific amplification factors are determined with numerical simulations, and a ready-for-use correlation equation of the amplification factor is formulated for a wide range of tank volumes and aspect ratios. This novel semi-analytic method substantially reduces computation time compared with numerical solvers, and the simple form of the water temperature function can help in formulating more detailed hot water tank models in energy system studies
Article 7(b)(i) of the 1970 UNESCO Convention : prohibition of import of inventoried cultural property
No full textDo differences in analyst quality matter for investors relying on consensus information?
Full text linkThis study investigates whether investors can reap economic benefits from analyzing differences in analyst quality. Although high-quality analysts’ average forecast is more accurate than the consensus forecast for firms with a large analyst following, the benefits of using high-quality analysts’ average forecasts are not economically significant. In contrast, the value of analyst quality differentiation exists in the second moment of forecasts. High-quality analysts’ forecast dispersion gives investors an advantage in dealing with uncertainty by predicting return volatility and providing opportunities for economically significant returns using option straddle and post-earnings announcement drift investment strategies