Solar-Powered Photocatalytic Fiber-Optic Cable Reactor for Waste Stream Remediation

The design and testing of a solar-powered fiber-optic cable reactor prototype for the photocatalytic destruction of organic pollutants is presented. A concentrating collector directs sunlight into a fiber-optic cable which transmits light to a TiO_2 photocatalyst immobilized on the fibers and immersed in a reaction solution. The performance of the reactor using solar and artificial UV radiation are compared. The system is also compared to another fiber-optic cable reactor having a 50 percent higher photocatalytic surface area-to-reactor volume ratio to investigate mass transport limitations. Reaction rates for the oxidation of 4-chlorophenol of 25 and 12 μM min^(-1) were measured for solar and artificial UV sources, respectively. The faster reaction rate using solar radiation is due to a higher UV light flux compared to the artificial source. Both fiber-optic reactor systems were determined not to be mass transport limited. Relative quantum efficiencies of ⌽ = 0.014 and ⌽ = 0.020 were determined for the solar and artificial irradiations, respectively. In agreement with previous findings, enhanced quantum efficiencies are attributed to a lower absorbed light intensity-to-photocatalytic surface area ratio. The solar reactor prototype was found to degrade effectively 4-chlorophenol and may prove useful for the in situ passive decontamination of subsurface and other remote environments

Reusable photocatalytic optical fibers for underground, deep-sea, and turbid water remediation

An approach for underground, deep, and turbid water remediation is presented based on optical fibers with a photocatalytic coating. Thus, photocatalytic TiO2 P25 nanoparticles immobilized in a poly(vinylidene difluoride) (PVDF) matrix are coated on polymeric optical fibers (POFs) and the photocatalytic performance of the system is assessed under artificial sunlight. To the best of our knowledge, poly(methyl methacrylate)-POF coated with TiO2/PVDF and the reusability of any type of POF for photocatalytic applications are not previously reported. The photocatalytic efficiency of the hybrid material in the degradation of ciprofloxacin (CIP) and its reusability are evaluated here. It is shown that 50 w/w% of TiO2 P25 achieves a degradation of 95% after 72 h under artificial sunlight and a reusability of three times leads to a loss of activity inferior to 11%. The efficient removal of ciprofloxacin and the stability of the POF coated with TiO2 P25 successfully demonstrate its suitability in the degradation of pollutants with potential application in regions with low light illumination, as in underground and deep water.Peer ReviewedPostprint (published version

Validation of the psychological insight scale: a new scale to assess psychological insight following a psychedelic experience

Introduction: As their name suggests, ‘psychedelic’ (mind-revealing) compounds are thought to catalyse processes of psychological insight; however, few satisfactory scales exist to sample this. This study sought to develop a new scale to measure psychological insight after a psychedelic experience: the Psychological Insight Scale (PIS). Methods: The PIS is a six- to seven-item questionnaire that enquires about psychological insight after a psychedelic experience (PIS-6) and accompanied behavioural changes (PIS item 7). In total, 886 participants took part in a study in which the PIS and other questionnaires were completed in a prospective fashion in relation to a planned psychedelic experience. For validation purposes, data from 279 participants were analysed from a non-specific ‘global psychedelic survey’ study. Results: Principal components analysis of PIS scores revealed a principal component explaining 73.57% of the variance, which displayed high internal consistency at multiple timepoints throughout the study (average Cronbach’s α = 0.94). Criterion validity was confirmed using the global psychedelic survey study, and convergent validity was confirmed via the Therapeutic-Realizations Scale. Furthermore, PIS scores significantly mediated the relationship between emotional breakthrough and long-term well-being. Conclusion: The PIS is complementary to current subjective measures used in psychedelic studies, most of which are completed in relation to the acute experience. Insight – as measured by the PIS – was found to be a key mediator of long-term psychological outcomes following a psychedelic experience. Future research may investigate how insight varies throughout a psychedelic process, its underlying neurobiology and how it impacts behaviour and mental health

Harmonization of accounting practices in the European Union

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The Pursuit of Happiness: Leadership Challenges of Recognising and Supporting Child Health and Wellbeing in the Early Years

This study examined the leadership approach to child health and wellbeing within the early-years sector; it drew upon the evidence from thirty-two practitioners and ten nursery managers. Practitioners evidenced the challenges in recognising the signs and symptoms of low wellbeing and in monitoring progress. A constructivist paradigm enabled qualitative data to be collected from an interactive questionnaire and three focus groups of nursery managers. Analysis was supported by two wellbeing models: the PERMA model (Positive Emotion, Engagement, Relationships, Meaning, and Accomplishment) and the SHANARRI wheel (Safe, Healthy, Achieving, Nurtured, Active, Respected, Responsible, Included). The findings accentuated the lack of confidence of practitioners in identifying the precursors of health and wellbeing, and their ability to monitor the progress to support children. In conclusion, a clear definition of health and wellbeing should be adopted by managers; their leadership is vital to support the training of practitioners sharing their knowledge and experience to less-qualified staff. The main issues to transpire highlighted that clear mandatory guidance should be available for early-years practitioners, and the creation of a bespoke early-years model to measure child health and wellbeing

Fiber-optic bundled array cable reactors for heterogeneous photocatalysis and waste stream remediation

NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document. Application of semiconductor photocatalysis in a fixed-bed fiber-optic bundled array cable reactor (OFR) for the purification of contaminated water is investigated in this thesis. An optical fiber cable is employed as a means of light transmission and distribution to solid-supported TiO2. The system is designed for remote delivery of light to the photocatalyst, to allow for measurement of light fluxes for direct determination of quantum yields and for reuse of the reactor to test various coatings and light input angles, and to minimize possible heat build-up and delamination problems. Experiments are carried out to determine the operational factors affecting the chemical efficiency of the OFR system. The uniformity and extent of light propagation down the fiber, the degree of light absorption by the TiO2 coating, the fiber diameter, the input light intensity, and the ability of the chemical substrates to diffuse into the TiO2 coating are determined to be important parameters. In addition, a TiO2 coating that minimizes the interfacial surface area of the quartz core and TiO2 particles and operation with incident irradiation angles near 90° enhance light propagation down the fibers. Relative quantum efficiencies in the OFR are found to be comparable to slurry-phase photochemical reaction systems. The OFR is shown to effectively degrade several model chemical contaminants such as pentachlorophenol (PCP), 4-chlorophenol (4CP), dichloroacetate (DCA), and oxalate (OX) under varying reaction conditions. Relatively high quantum efficiencies of [...] = 0.010, 0.015, 0.08, and 0.17, respectively, and complete mineralization to CO2, H2O and HCl are observed. When iron(III)-doped quantum-sized (Q) TiO2 (Fe/Q-TiO2) is used as a photocatalytic coating, the extent of linear light transmission in a single fiber is doubled relative to Degussa P25. However, the Fe/Q-TiO2 coating is found to have inferior light absorption properties and chemical reactivity leading to lower relative quantum efficiencies. A concentrating, solar powered prototype OFR is designed and tested. Photoefficiencies with sunlight were comparable to that achieved with a Xe-arc source. Lower light intensity-to-photocatalytic surface area ratios result in increased relative quantum efficiencies. A mathematical model of a fiber-optic bundled array reactor system is developed using Langmuir-Hinshelwood kinetics and compared to experimental data. A global quantum efficiency, [...], is defined and used as a model fitting parameter. It incorporates reaction parameters such as the absorbed light intensity, the intrinsic rate constant, and the effects of other adsorbed reactants and reaction intermediates. An empirical term to describe the radiation field within the coated fiber is derived and normalized by the coating photocatalyst particle concentration to account for the inverse relationship between the absorbed light intensity and the reaction quantum efficiency. The [...] is determined to be independent of the absorbed light intensity and calculated values are in excellent agreement with experimental values. An analysis of conventional and advanced remediation technologies is performed (Appendix). The chemistry and engineering behind advanced oxidation systems is reviewed, and a means of technical evaluation and comparison is presented. The "electrical energy per order," or EEO is defined as the electrical energy required to reduce the concentration of a given pollutant by one order of magnitude in 1000 gal of water. The EEO can be used to compare the efficacy of remediation technologies with other AOT's and conventional systems for a particular cleanup application