317 research outputs found

    Effects of Preparation Conditions on the Yield and Embedding Ratio of Vinyl Silicone Oil Microcapsules

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    Self-healing materials could repair themselves without external influences when they are damaged. In this paper, microcapsules are prepared by in-situ polymerization method, utilizing vinyl silicone oil as core material, polyurea formaldehyde as wall material and polyvinyl alcohol as dispersant. The morphology and structure of the microcapsules are tested with scanning electron microscopy, optical microscopy and laser particle analyzer. Effect of the reaction temperature, stirring speed and polyvinyl alcohol concentration on the yield, embedding ratio, particle size and its distribution are studied. Results show that the microcapsules can be successfully prepared by in-situ polymerization method. Under the reaction condition of temperature 60 °C, stirring speed 1000 r/min, dispersant concentration 0.1 wt.%, the yield and embedding ratio of the microcapsule are found to be 52.5 % and 50.1 %, respectively. The prepared microcapsules have smooth surface, good dispersibility, narrow particle size distribution and the average particle size is 13 μm

    Optimisation of wastewater treatment strategies in eco-industrial parks:Technology, location and transport

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    The expanding population and rapid urbanisation, in particular in the Global South, are leading to global challenges on resource supply stress and rising waste generation. A transformation to resource-circular systems and sustainable recovery of carbon-containing and nutrient-rich waste offers a way to tackle such challenges. Eco-industrial parks have the potential to capture symbioses across individual waste producers, leading to more effective waste-recovery schemes. With whole-system design, economically attractive approaches can be achieved, reducing the environmental impacts while increasing the recovery of high-value resources. In this paper, an optimisation framework is developed to enable such design, allowing for wide ranging treatment options to be considered capturing both technological and financial detail. As well as technology selection, the framework also accounts for spatial aspects, with the design of suitable transport networks playing a key role. A range of scenarios are investigated using the network, highlighting the multi-faceted nature of the problem. The need to incorporate the impact of resource recovery at the design stage is shown to be of particular importance

    Optimal control towards sustainable wastewater treatment plants based on multi-agent reinforcement learning

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    Wastewater treatment plants are designed to eliminate pollutants and alleviate environmental pollution. However, the construction and operation of WWTPs consume resources, emit greenhouse gases (GHGs) and produce residual sludge, thus require further optimization. WWTPs are complex to control and optimize because of high nonlinearity and variation. This study used a novel technique, multi-agent deep reinforcement learning, to simultaneously optimize dissolved oxygen and chemical dosage in a WWTP. The reward function was specially designed from life cycle perspective to achieve sustainable optimization. Five scenarios were considered: baseline, three different effluent quality and cost-oriented scenarios. The result shows that optimization based on LCA has lower environmental impacts compared to baseline scenario, as cost, energy consumption and greenhouse gas emissions reduce to 0.890 CNY/m3-ww, 0.530 kWh/m3-ww, 2.491 kg CO2-eq/m3-ww respectively. The cost-oriented control strategy exhibits comparable overall performance to the LCA driven strategy since it sacrifices environmental bene ts but has lower cost as 0.873 CNY/m3-ww. It is worth mentioning that the retrofitting of WWTPs based on resources should be implemented with the consideration of impact transfer. Specifically, LCA SW scenario decreases 10 kg PO4-eq in eutrophication potential compared to the baseline within 10 days, while significantly increases other indicators. The major contributors of each indicator are identified for future study and improvement. Last, the author discussed that novel dynamic control strategies required advanced sensors or a large amount of data, so the selection of control strategies should also consider economic and ecological conditions

    Having a monk in the family and all-cause mortality: a seven-year prospective cohort study

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    Religious celibate monks at the household level possibly reduce all-cause mortality risk among non-monk older Tibetans. This study aims to investigate the association between having a celibate monk in a family and the all-cause mortality of non-monk household members in a Tibetan population. Baseline interviews were conducted for 713 agropastoral Amdo Tibetans aged ≥50 years residing in the eastern Tibetan Plateau from 2016 to 2017. The Cox mixed-effects regression model was used to estimate the association between having a celibate monk in a household and the mortality risk of other non-monk household members. Potential confounders included age, sex, household size, educational attainment, household wealth (measured as the number of yaks), marital status, and annual expenditure. During a median follow-up of 7 years, 54 deaths were identified. The results showed that people living in households with celibate monks had a lower risk of all-cause mortality (hazard ratio: 0.31, 95% confidence interval: 0.14, 0.67) as compared with those living in households without celibate monks. The results remained robust after controlling for confounders, suggesting that religious celibate monks at the household level were associated with lower all-cause mortality among non-monk older household members

    Electron Fluxes in Biocathode Bioelectrochemical Systems Performing Dechlorination of Chlorinated Aliphatic Hydrocarbons

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    Bioelectrochemical systems (BESs) are regarded as a promising approach for the enhanced dechlorination of chlorinated aliphatic hydrocarbons (CAHs). However, the electron distribution and transfer considering dechlorination, methanogenesis, and other bioprocesses in these systems are little understood. This study investigated the electron fluxes in biocathode BES performing dechlorination of three typical CAHs, 1,1,2,2-tetrachloroethene (PCE), 1,1,2-trichloroethene (TCE) and 1,2-dichloroethane (1,2-DCA). Anaerobic sludge was inoculated to cathode and biocathode was acclimated by the direct acclimation and selection. The constructed biocathode at −0.26 V had significantly higher dechlorination efficiency (E24h > 99.0%) than the opened circuit (E24h of 17.2–27.5%) and abiotic cathode (E24h of 5.5–10.8%), respectively. Cyclic voltammetry analysis demonstrated the enhanced cathodic current and the positive shift of onset potential in the cathodic biofilm. Under autotrophic conditions with electrons from the cathode as sole energy source (columbic efficiencies of 80.4–90.0%) and bicarbonate as sole carbon source, CAHs dechlorination efficiencies were still maintained at 85.0 ± 2.0%, 91.4 ± 1.8%, and 84.9 ± 3.1% for PCE, TCE, and 1,2-DCA, respectively. Cis-1,2-dichloroethene was the final product for PCE and TCE, while 1,2-DCA went through a different dechlorination pathway with the non-toxic ethene as the final metabolite. Methane was the main by-product of the heterotrophic biocathode, and methane production could be enhanced to some extent by electrochemical stimulation. The various electron fluxes originating from the cathode and oxidation of organic substrates might be responsible for the enhanced CAHs dechlorination, while methane generation and bacterial growth would probably reduce the fraction of electrons provided for CAH dechlorination. The study deals with the dechlorination and competitive bioprocesses in CAH-dechlorinating biocathodes with a focus on electron fluxes

    Central nervous system toxicity of metallic nanoparticles

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    Nanomaterials (NMs) are increasingly used for the therapy, diagnosis, and monitoring of disease- or drug-induced mechanisms in the human biological system. In view of their small size, after certain modifications, NMs have the capacity to bypass or cross the blood–brain barrier. Nanotechnology is particularly advantageous in the field of neurology. Examples may include the utilization of nanoparticle (NP)-based drug carriers to readily cross the blood–brain barrier to treat central nervous system (CNS) diseases, nanoscaffolds for axonal regeneration, nanoelectromechanical systems in neurological operations, and NPs in molecular imaging and CNS imaging. However, NPs can also be potentially hazardous to the CNS in terms of nano-neurotoxicity via several possible mechanisms, such as oxidative stress, autophagy, and lysosome dysfunction, and the activation of certain signaling pathways. In this review, we discuss the dual effect of NMs on the CNS and the mechanisms involved. The limitations of the current research are also discussed

    Statistical Optimization of Operational Parameters for Enhanced Naphthalene Degradation by Photocatalyst

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    The optimization of operational parameters for enhanced naphthalene degradation by TiO2/Fe3O4-SiO2 (TFS) photocatalyst was conducted using statistical experimental design and analysis. Central composite design method of response surface methodology (RSM) was adopted to investigate the optimum value of the selected factors for achieving maximum naphthalene degradation. Experimental results showed that irradiation time, pH, and TFS photocatalyst loading had significant influence on naphthalene degradation and the maximum degradation rate of 97.39% was predicted when the operational parameters were irradiation time 97.1 min, pH 2.1, and catalyst loading 0.962 g/L, respectively. The results were further verified by repeated experiments under optimal conditions. The excellent correlation between predicted and measured values further confirmed the validity and practicability of this statistical optimum strategy

    In situ Carbon Modification of g-C3N4 from Urea Co-crystal with Enhanced Photocatalytic Activity Towards Degradation of Organic Dyes Under Visible Light

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    An in situ strategy was introduced for synthesizing carbon modified graphitic carbon nitride(g-C3N4) by using urea/4-aminobenzoic acid(PABA) co-crystal(PABA@Urea) as precursor materials. Via co-calcination of the PABA co-former and the urea in PABA@Urea co-crystals, C guest species were generated and compounded into g-C3N4 matrix in situ by replacing the lattice N of the carbon nitride and forming carbon dots onto its layer surface. The carbon modification dramatically enhanced visible-light harvesting and charge carrier separation. Therefore, visible light photo-catalytic oxidation of methylene blue(MB) pollution in water over the carbon modified g-C3N4 (C/g-C3N4) was notably improved. Up to 99% of methylene blue(MB) was eliminated within 60 min by the optimal sample prepared from the PABA@Urea co-crystal with a PABA content of 0.1%(mass ratio), faster than the degradation rate over bare g-C3N4. The present study demonstrates a new way to boost up the photocatalysis performance of g-C3N4, which holds great potential concerning the degradation of organic dyes from water
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