A brief review on nano phase change material-based polymer encapsulation for thermal energy storage systems

© The Author(s) 2021. This chapter is licensed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/).In recent years, considerable attention has been given to phase change materials (PCMs) that is suggested as a possible medium for thermal energy storage. PCM encapsulation technology is an efficient method of enhancing thermal conductivity and solving problems of corrosion and leakage during a charging process. Moreover, nanoencapsulation of phase change materials with polymer has several benefits as a thermal energy storage media, such as small-scale, high heat transfer efficiency and large specific surface area. However, the lower thermal conductivity (TC) of PCMs hinders the thermal efficiency of the polymer based nano-capsules. This review covers the effect of polymer encapsulation on PCMs while concentrating on providing solutions related to improving the thermal efficiency of system.Peer reviewe

An Efficient Synthesis and Photoelectric Properties of Green Carbon Quantum Dots with High Fluorescent Quantum Yield

© 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/)To greatly improve the production quality and efficiency of carbon quantum dots (CQDs), and provide a new approach for the large-scale production of high-quality CQDs, green carbon quantum dots (g-CQDs) with high product yield (PY) and high fluorescent quantum yield (QY) were synthesized by an efficient one-step solvothermal method with 2,7-dihydroxynaphthalene as the carbon source and ethylenediamine as the nitrogen dopant in this study. The PY and QY of g-CQDs were optimised by adjusting reaction parameters such as an amount of added ethylenediamine, reaction temperature, and reaction duration. The results showed that the maximum PY and QY values of g-CQDs were achieved, which were 70.90% and 62.98%, respectively when the amount of added ethylenediamine, reaction temperature, and reaction duration were 4 mL, 180 °C, and 12 h, respectively. With the optimised QY value of g-CQDs, white light emitting diodes (white LEDs) were prepared by combining g-CQDs and blue chip. The colour rendering index of white LEDs reached 87, and the correlated colour temperature was 2520 K, which belongs to the warm white light area and is suitable for indoor lighting. These results indicate that g-CQDs have potential and wide application prospects in the field of white LEDs.Peer reviewedFinal Published versio

Preparation and thermophysical characterisation analysis of potential nano-phase transition materials for thermal energy storage applications

© 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).The efficacious use of phase change materials (PCMs) is mainly confined by their poor thermal conductivity (TC). In this study, multiwalled carbon nanotubes (MWCNTs), graphene nanoplatelets (GNP) and titanium oxide (TiO2) based single, and novel hybrid nano additives were incorporated into paraffin, a typical PCM, to find the optimal composite which could not only enhance the thermal conductivity but also limit the latent heat. Both unitary and hybrid nanoparticles at five different concentrations (0.2, 0.4, 0.6, 0.8 & 1.0 wt.%) were investigated using various characterisation techniques, including FT-IR, XRD, DSC, TGA, and TC apparatus. The results depicted good intermolecular interactions between the PCM and the nanoparticles and showed that the dispersion of nanoparticles within the PCM did not affect the chemical structure of pristine paraffin but enhanced its thermal and chemical stability. Novel hybrid nanocomposites were found to be more stable and exhibit better thermal performance than single nanocomposites. The highest value of thermal conductivity was observed at 1.0 wt.% of GNP+MWCNTs hybrid particles based PCM with a maximum enhancement of 170% at 25 °C. However, compared with single and hybrid carbon-based nanofillers, TiO2 based mono and hybrid nano-PCM showed a minimum reduction in the latent heat with a maximum decrease of -3.7%, -5.2%, and -5.5% at 1 wt.% of TiO2, TiO2+GNP and TiO2+MWCNTs, respectively. The significant improvement in the thermal properties of PCMs with the inclusion of these nanofillers indicates that they have the potential to be employed in thermal energy storage applications.Peer reviewe

Enhancing Thermal Energy Storage in Buildings with Novel Functionalised MWCNTs-Enhanced Phase Change Materials: Towards Efficient and Stable Solutions

© 2023 The Author(s). Published by Elsevier Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY), https://creativecommons.org/licenses/by/4.0/Phase change materials (PCMs) are a promising panacea to tackle the intermittency of renewable energy sources, but their thermal performance is limited by low thermal conductivity (TC). This pioneering work investigates the potential of organic PCM-enriched surface-modified and un-modified multi-walled carbon nanotubes (MWCNTs) for low-temperature thermal energy storage (TES) applications. The functionalised and un-functionalised MWCNTs enhanced PCM have demonstrated a TC enhancement of 158 % and 147 %, respectively, at 25 °C. However, the TC value of the unmodified MWCNTs-based PCM dropped by 52.5 % after 48 h at 25 °C, while that of the functionalised MWCNTs-based PCM remained stable. A DSC analysis of up to 200 thermal cycles confirmed that the surface-modified and un-modified MWCNTs had no major effect on the peak melting and cooling temperatures of the nano-enhanced PCMs although a minor decrease of 7.5 % and 7.7 % in the melting and crystallisation enthalpies, respectively, was noticed with the inclusion of functionalised MWCNTs. Moreover, functionalised MWCNTs incorporated PCMs have led to increases in specific heat capacity by 23 % with an optimal melting enthalpy value of 229.7 J/g. In addition, no super-cooling, no phase segregation, and a small phase change temperature were noticed with these nano-enhanced PCMs. Finally, no chemical interaction from nano-PCMs was seen in the FT-IR spectra with the incorporation of both functionalised and un-treated MWCNTs. It is evident that the functionalised MWCNT-based PCM has better thermal stability and it offers a promising alternative for improving thermal storage and management capabilities in buildings, contributing to a sustainable and energy-efficient building design.Peer reviewe

Mitigation measures of the electric field in the medium-voltage power module:Effect of voltage types and recommendations for designers

Abstract In the medium‐voltage silicon carbide device power module, the higher voltage level will induce higher electric field stress in critical internal points such as the edge of the conductor on the direct bonded copper (DBC) substrate. This can lead to partial discharge and subsequently accelerated ageing of the insulating medium in the module. Therefore, it is important to reduce the high electric field strength. Herein, the related technical methods of electric field control are reviewed and compared by combining the ease of implementation in real power module and the field control effect. In addition, systematic explanations of the electric field drift and influencing factors of the electric field strength under different voltage types within different module structures are presented. Finally, for half‐bridge power modules with different substrates structures, suggestions on how to implement non‐linear field‐dependent materials to reduce the electric field strength are given

Treatment with gelsolin reduces brain inflammation and apoptotic signaling in mice following thermal injury

<p>Abstract</p> <p>Background</p> <p>Burn survivors develop long-term cognitive impairment with increased inflammation and apoptosis in the brain. Gelsolin, an actin-binding protein with capping and severing activities, plays a crucial role in the septic response. We investigated if gelsolin infusion could attenuate neural damage in burned mice.</p> <p>Methods</p> <p>Mice with 15% total body surface area burns were injected intravenously with bovine serum albumin as placebo (2 mg/kg), or with low (2 mg/kg) or high doses (20 mg/kg) of gelsolin. Samples were harvested at 8, 24, 48 and 72 hours postburn. The immune function of splenic T cells was analyzed. Cerebral pathology was examined by hematoxylin/eosin staining, while activated glial cells and infiltrating leukocytes were detected by immunohistochemistry. Cerebral cytokine mRNAs were further assessed by quantitative real-time PCR, while apoptosis was evaluated by caspase-3. Neural damage was determined using enzyme-linked immunosorbent assay of neuron-specific enolase (NSE) and soluble protein-100 (S-100). Finally, cerebral phospho-ERK expression was measured by western blot.</p> <p>Results</p> <p>Gelsolin significantly improved the outcomes of mice following major burns in a dose-dependent manner. The survival rate was improved by high dose gelsolin treatment compared with the placebo group (56.67% vs. 30%). Although there was no significant improvement in outcome in mice receiving low dose gelsolin (30%), survival time was prolonged against the placebo control (43.1 ± 4.5 h vs. 35.5 ± 5.0 h; P < 0.05). Burn-induced T cell suppression was greatly alleviated by high dose gelsolin treatment. Concurrently, cerebral abnormalities were greatly ameliorated as shown by reduced NSE and S-100 content of brain, decreased cytokine mRNA expressions, suppressed microglial activation, and enhanced infiltration of CD11b+ and CD45+ cells into the brain. Furthermore, the elevated caspase-3 activity seen following burn injury was remarkably reduced by high dose gelsolin treatment along with down-regulation of phospho-ERK expression.</p> <p>Conclusion</p> <p>Exogenous gelsolin infusion improves survival of mice following major burn injury by partially attenuating inflammation and apoptosis in brain, and by enhancing peripheral T lymphocyte function as well. These data suggest a novel and effective strategy to combat excessive neuroinflammation and to preserve cognition in the setting of major burns.</p

[1,2-Bis(diphenyl­phosphino)ethane-κ2 P,P′](2-carboxyl­atothio­phenolato-κ2 O,S)nickel(II) methanol solvate

In the title complex, [Ni(C7H4O2S)(C26H24P2)]·CH3OH, the nickel(II) centre adopts an approximately square-planar geometry, with the Ni atom coordinating to the S and O atoms of the bidentate thio­salicylate ligand and the two P atoms of the chelating Ph2PCH2CH2PPh2 ligand. There is hydrogen bonding between the methanol solvent mol­ecule and the carbonyl O atom of the thio­salicylate ligand