Performance of phase change material boards under natural convection

The high thermal storage capacity of phase change material (PCM) can reduce energy consumption in buildings through energy storage and release when combined with renewable energy sources, night cooling, etc. PCM boards can be used to absorb heat gains during daytime and release heat at night. In this paper, the thermal performance of an environmental chamber fitted with phase change material boards has been investigated. During a full-cycle experiment, i.e. charging–releasing cycle, the PCM boards on a wall can reduce the interior wall surface temperature during the charging process, whereas the PCM wall surface temperature is higher than that of the other walls during the heat releasing process. It is found that the heat flux density of the PCM wall in the melting zone is almost twice as large as that of ordinary wall. Also, the heat-insulation performance of a PCM wall is better than that of an ordinary wall during the charging process, while during the heat discharging process, the PCM wall releases more heat energy. The convective heat transfer coefficient of PCM wall surface calculated using equations for a normal wall material produces an underestimation of this coefficient. The high convective heat transfer coefficient for a PCM wall is due to the increased energy exchange between the wall and indoor air.

Effects of chronic consumption of fruit and vegetable puree-based drinks on vasodilation, plasma oxidative stability and antioxidant status

Background: Fruit and vegetable-rich diets are associated with a reduced cardiovascular disease (CVD) risk. This protective effect may be a result of the phytochemicals present within fruits and vegetables (F&V). However, there can be considerable variation in the content of phytochemical composition of whole F&V depending on growing location, cultivar, season and agricultural practices, etc. Therefore, the present study investigated the effects of consuming fruits and vegetables as puree-based drinks (FVPD) daily on vasodilation, phytochemical bioavailability, antioxidant status and other CVD risk factors. FVPD was chosen to provide a standardised source of F&V material that could be delivered from the same batch to all subjects during each treatment arm of the study. Methods: Thirty-nine subjects completed the randomised, controlled, cross-over dietary intervention. Subjects were randomised to consume 200 mL of FVPD (or fruit-flavoured control), daily for 6 weeks with an 8-week washout period between treatments. Dietary intake was measured using two 5-day diet records during each cross-over arm of the study. Blood and urine samples were collected before and after each intervention and vasodilation assessed in 19 subjects using laser Doppler imaging with iontophoresis. Results: FVPD significantly increased dietary vitamin C and carotenoids (P < 0.001), and concomitantly increased plasma α- and β-carotene (P < 0.001) with a near-significant increase in endothelium-dependent vasodilation (P = 0.060). Conclusions: Overall, the findings obtained in the present study showed that FVPD were a useful vehicle to increase fruit and vegetable intake, significantly increasing dietary and plasma phytochemical concentrations with a trend towards increased endothelium-dependent vasodilation.

The mirror of consumption: celebritization, developmental consumption and the shifting cultural politics of fair trade

This paper explores the shifting cultural politics of development as expressed in the changing narratives and discursive transparencies of fair trade marketing tactics in the UK. Pursued through what I call ‘developmental consumption’ and the increasing celebritization of development, it is now through the global media mega-star that the subaltern speaks. After a more general discussion of the implications of the celebritization of development, specific analysis focuses on two parallel processes complicit in the ‘mainstreaming’ of fair trade markets and the desire to develop fair trade as a product of ‘quality’. The first involves improving the taste of fair trade commodities through alterations in their material supply chains while the second involves novel marketing narratives designed to invoke these conventions of quality through highly meaningful discursive and visual means. The later process is conceptualized through the theoretical device of the shifting ‘embodiments’ of fair trade which have moved from small farmers’ livelihoods, to landscapes of ‘quality’, to increasing congeries of celebrities such as Chris Martin from the UK band Coldplay. These shifts encapsulate what is referred to here as fair trade’s Faustian Bargain and its ambiguous results: the creation of increasing economic returns and, thus, more development through the movement of fair trade goods into mainstream retail markets at the same time there is a de-centering of the historical discursive transparency at the core of fair trade’s moral economy. Here, then, the celebritization of fair trade has the potential to create ‘the mirror of consumption’, whereby, our gaze is reflected back upon ourselves in the form of ‘the rich and famous’ Northern celebrity muddling the ethics of care developed by connecting consumers to fair trade farmers and their livelihoods. The paper concludes with a consideration of development and fair trade politics in the context of their growing aestheticization and celebritization.

‘Did Ronald McDonald also tend to scare you as a child?’: working to emplace consumption, commodities, and citizen-students in a large classroom setting

So-called ‘radical’ and ‘critical’ pedagogy seems to be everywhere these days on the landscapes of geographical teaching praxis and theory. Part of the remit of radical/critical pedagogy involves a de-centring of the traditional ‘banking’ method of pedagogical praxis. Yet, how do we challenge this ‘banking’ model of knowledge transmission in both a large-class setting and around the topic of commodity geographies where the banking model of information transfer still holds sway? This paper presents a theoretically and pedagogically driven argument, as well as a series of practical teaching ‘techniques’ and tools—mind-mapping and group work—designed to promote ‘deep learning’ and a progressive political potential in a first-year large-scale geography course centred around lectures on the Geographies of Consumption and Material Culture. Here students are not only asked to place themselves within and without the academic materials and other media but are urged to make intimate connections between themselves and their own consumptive acts and the commodity networks in which they are enmeshed. Thus, perhaps pedagogy needs to be emplaced firmly within the realms of research practice rather than as simply the transference of research findings.