Flash-type barometric desalination plant powered by waste heat from electricity power stations in Cyprus

This paper describes and evaluates the results of a study into the problems of freshwater production and shortages on the island of Cyprus. The use of a novel barometric flash-type desalinator, driven by otherwise waste-heat from the island's power-stations, is proposed as a means of increasing freshwater supplies. Mathematical models are described and used to investigate the thermodynamic performance and economic viability of the proposed system. Although water and electricity-supply data for the island of Cyprus were used for the purposes of this investigation, the overall findings are thought to have a wider applicability.Desalination Solar energy Renewable energy Cogeneration Power station Water

Optimization of the photovoltaic thermal (PV/T) collector absorber

In an effort to reduce the cost of conventional fin and tube photovoltaic thermal (PV/T) collectors a novel mathematical analysis was developed which determines the optimum absorber plate configuration having the least material content and thus cost, whilst maintaining high collection efficiency. The analysis was based on the “low-flow” concept whose advantages include: improved system performance, smaller pump (less expensive with lower power consumption), smaller diameter tubes requiring lower thickness and thus cost of insulation, less construction power and time for the optimum absorber configuration. From the optimization methodology developed it was found that very thin fins (typically 50 μm) and small tubes (of 1.65 mm inside diameter for the risers, in the header and riser arrangement and 4.83 mm for the serpentine arrangement), with a tube spacing of 62 mm and 64 mm (both corresponding to 97% fin efficiency) and a mass of 1.185 kg/m2 and 2.140 kg/m2, respectively, can be used. This optimum serpentine absorber plate contains 40.50% less material content and mass, as compared to the serpentine prototype proposed by others. In one such design a mass of 3.596 kg/m2 was used (with 10 mm diameter tubes, 95 mm tube spacing and 200 μm thick absorber). To predict the performance of the determined optimum configurations, a steady-state model (using the EES code) was developed. To validate the steady-state model two prototypes, one in Header and Riser and the other in Serpentine configuration, were built and tested. It was found from the experiments that there is a good agreement between the computational and the experimental results. Moreover, it was found that optimum PV/T configurations do indeed have thermal and electrical performance comparable to non-optimum ones of greater mass and cos

Expanding flavone and flavonol production capabilities in Escherichia coli

Flavones and flavonols are important classes of flavonoids with nutraceutical and pharmacological value, and their production by fermentation with recombinant microorganisms promises to be a scalable and economically favorable alternative to extraction from plant sources. Flavones and flavonols have been produced recombinantly in a number of microorganisms, with Saccharomyces cerevisiae typically being a preferred production host for these compounds due to higher yields and titers of precursor compounds, as well as generally improved ability to functionally express cytochrome P450 enzymes without requiring modification to improve their solubility. Recently, a rapid prototyping platform has been developed for high-value compounds in E. coli, and a number of gatekeeper (2S)-flavanones, from which flavones and flavonols can be derived, have been produced to high titers in E. coli using this platform. In this study, we extended these metabolic pathways using the previously reported platform to produce apigenin, chrysin, luteolin and kaempferol from the gatekeeper flavonoids naringenin, pinocembrin and eriodictyol by the expression of either type-I flavone synthases (FNS-I) or type-II flavone synthases (FNS-II) for flavone biosynthesis, and by the expression of flavanone 3-dioxygenases (F3H) and flavonol synthases (FLS) for the production of the flavonol kaempferol. In our best-performing strains, titers of apigenin and kaempferol reached 128 mg L−1 and 151 mg L−1 in 96-DeepWell plates in cultures supplemented with an additional 3 mM tyrosine, though titers for chrysin (6.8 mg L−1) from phenylalanine, and luteolin (5.0 mg L−1) from caffeic acid were considerably lower. In strains with upregulated tyrosine production, apigenin and kaempferol titers reached 80.2 mg L−1 and 42.4 mg L−1 respectively, without the further supplementation of tyrosine beyond the amount present in the rich medium. Notably, the highest apigenin, chrysin and luteolin titers were achieved with FNS-II enzymes, suggesting that cytochrome P450s can show competitive performance compared with non-cytochrome P450 enzymes in prokaryotes for the production of flavones

Bioproduction of methylated phenylpropenes and isoeugenol in Escherichia coli

Phenylpropenes are a class of natural products that are synthesised by a vast range of plant species and hold considerable promise in the flavour and fragrance industries. Many in vitro studies have been carried out to elucidate and characterise the enzymes responsible for the production of these volatile compounds. However, there is a scarcity of studies demonstrating the in vivo production of phenylpropenes in microbial cell factories. In this study, we engineered Escherichia coli to produce methylchavicol, methyleugenol and isoeugenol from their respective phenylacrylic acid precursors. We achieved this by extending and modifying a previously optimised heterologous pathway for the biosynthesis of chavicol and eugenol. We explored the potential of six S-adenosyl L-methionine (SAM)-dependent O-methyltransferases to produce methylchavicol and methyleugenol from chavicol and eugenol, respectively. Additionally, we examined two isoeugenol synthases for the production of isoeugenol from coniferyl acetate. The best-performing strains in this study were able to achieve titres of 13 mg L−1 methylchavicol, 59 mg L−1 methyleugenol and 361 mg L−1  isoeugenol after feeding with their appropriate phenylacrylic acid substrates. We were able to further increase the methyleugenol titre to 117 mg L−1 by supplementation with methionine to facilitate SAM recycling. Moreover, we report the biosynthesis of methylchavicol and methyleugenol from L-tyrosine through pathways involving six and eight enzymatic steps, respectively

Translanguaging through the lens of drama and digital storytelling: shaping new language pedagogies in the classroom

This article investigates ‘translanguaging’ through the lens of drama and digital storytelling and the way it can impact on language pedagogy. The case-study focuses on the making of the digital story Irene – A refugee’s story. The research data was analysed under key questions relating to drama, transformative pedagogy and translanguaging spaces. Research findings revealed how bringing drama and digital storytelling together allowed these young children to view themselves and the world differently and experience themselves as bidialectal learners. Children’s translanguaging practices encouraged them to move beyond traditional pedagogic ideologies and to think more independently and creatively. These young children were able to think, discuss, explore and evaluate through both linguistic varieties of Cypriot Greek (CG) and Standard Modern Greek (SMG) and adopt translanguaging practices. The digital storytelling process was viewed as performative, self-reflective and transformative. The research study showed the importance of trying out new language pedagogies in the classroom