Latent Heat Storage with Phase Change Materials (PCMs)

Latent heat thermal energy storage with phase change materials (PCMs) is attractive since providing a high energy density storage due to the phase change by solidification/melting at constant temperature. Relative to sensible heat energy storage systems, latent heat storage with PCMs requires a smaller weight and volume of material for a given amount of captured/stored energy, and has the capacity to store heat of fusion at a constant or nearly constant temperature, thus maintaining a high and constant temperature difference between the heat exchanging surface and the PCMs.The present review paper will summarize the required properties of PCMs, with their respective advantages and disadvantages; the current state of development and manufacturing; the development of PCM applications, including their incorporation into heat exchangers, insertion of a metal matrix into the PCM, the use of PCM dispersed with high conductivity particles. PCM uses will be illustrated through some case-studies

Effect of resistance training on muscle properties and function in women with generalized joint hypermobility: a single-blind pragmatic randomized controlled trial.

BACKGROUND Generalized joint hypermobility is defined as an excessive range of motion in several joints. Having joint hypermobility is not a pathology, but when associated with pain and other symptoms, it might affect health and function. Evidence for physiotherapy management is sparse and resistance training might be a possible intervention. Thus, the effects of 12-week resistance-training on muscle properties and function in women with generalized joint hypermobility were evaluated. METHODS In this single-blind randomized controlled trial women between 20 and 40 years with generalized joint hypermobility (Beighton score at least 6/9) were included. Participants were randomly allocated to 12-week resistance training twice weekly (experimental) or no lifestyle change (control). Resistance training focused on leg and trunk muscles. Primary outcome was muscle strength; additional outcomes included muscle properties, like muscle mass and density, functional activities, pain and disability. Training adherence and adverse events were recorded. RESULTS Of 51 participating women 27 were randomised to training and 24 into the control group. In each group 11 women had joint hypermobility syndrome, fulfilling the Brighton criteria, while 24 (89%) in the training group and 21 (88%) in the control group mentioned any pain. The mean strength of knee extensors varied in the training group from 0.63 (sd 0.16) N/bm before training to 0.64 (sd 0.17) N/bm after training and in the control group from 0.53 (sd 0.14) N/bm to 0.54 (sd 0.15) N/bm. For this and all other outcome measures, no significant differences between the groups due to the intervention were found, with many variables showing high standard deviations. Adherence to the training was good with 63% of participants performing more than 80% of sessions. One adverse event occurred during training, which was not clearly associated to the training. Four participants had to stop the training early. CONCLUSIONS No improvement in strength or muscle mass by self-guided resistance training was found. Low resistance levels, as well as the choice of outcome measures were possible reasons. A more individualized and better guided training might be important. However, program adherence was good with few side effects or problems triggered by the resistance training. TRIAL REGISTRATION This trial was prospectively registered in the ISRCTN registry ( www.isrctn.com , BMC, Springer Nature) on July 16, 2013 as ISRCTN90224545 . The first participant was enrolled at October 25, 2013

The impact of an interaction-based classroom program on executive function development in low-SES preschoolers: first support for effectiveness

Studies have shown that children from a low socioeconomic status (SES) family are likely to have lower academic scores, indicating an SES-achievement gap. This inequality already starts in preschool and persists throughout children’s lives. Since executive functions (EFs) have been put forward as contributing factors in this SES-achievement gap, it is crucial to target early EF development to remediate the adverse effects of poverty. In this quasi-experimental study, a classroom program delivered by teachers (i.e., “Put your EF glasses on”) was implemented to strengthen preschoolers’ EFs, consistent with the idea that well-developed EFs can foster school readiness and prevent school failure. The program aimed to boost children’s EFs through high-quality teacher-child interactions, EF-supporting activities (e.g., games), and a supportive classroom structure. Teachers (n = 24) and children (n = 224, Mage = 52.61 months) from 8 Belgian schools participated in this quasi-experimental pilot study and were divided into experimental and control groups. Teachers in the experimental group carried out the program (receiving materials and coaching to support implementation), whereas teachers in the control group practiced teaching as usual. Before and after the program, all teachers filled out the BRIEF-P, a questionnaire about daily executive problems in preschool children. We compared the effect of the classroom program in low-SES versus middle-to-high-SES children on EF problem scores. Results revealed that all low-SES children started with significantly higher EF problems (total problem score, working memory, inhibition, and planning and organizing) scores than middle-to-high-SES children. A positive effect of the program was found among low-SES children. More specifically, EF problems (total problem score, working memory, shifting, and planning and organizing) remained stable over time in the low-SES group in the experimental group, but there was no program effect on emotional control and inhibition. In the control group, these EF problems increased for low-SES children, expanding the gap between low and middle-to-high-SES children. There were no program effects for middle-to-high-SES children. These results show that a teacher-mediated classroom program can support EF development, especially in preschoolers at sociodemographic risk

Cultural universality and specificity of teacher-student relationship: a qualitative study in Belgian, Chinese, and Italian primary school teachers

Extensive evidence highlights the significant influence of dyadic, emotional teacher-student relationship (TSR) on students' cognitive functioning, socio-emotional development, and overall well-being. However, it remains unclear whether the TSR construct and its manifestations can be generalized across cultures. This qualitative study investigated TSR among 60 primary school teachers in Belgium, China, and Italy (i.e., countries with varying positions on the collectivistic-individualistic continuum of culture). Through semi-structured interviews and metatheme analysis, the study examined the similarities and differences in TSR across these countries, revealing a nuanced and diverse picture in various cultural contexts. The findings align with the existing TSR model by including dimensions of closeness, conflict, and dependency, while also extending the model to identify additional dimensions such as authority, balance, distance, fairness, increasing student motivation, patience, and strictness. Regarding cultural perspective, teachers from these three countries exhibited similar conceptualizations of closeness, conflict, fairness, increasing student motivation, patience, and strictness, whereas the conceptualization of dependency, authority, balance, and distance may be influenced by (collectivistic versus individualistic) culture. Moreover, the manifestations of TSR varied across countries, highlighting the influence of cultural factors such as cultural norms, collectivistic versus individualistic values, and the perceived legitimacy of teacher authority. These findings shed light on the complexities of TSR across countries and emphasize the significance of culturally sensitive approaches in fostering positive TSR in education