Novel silica filled deep eutectic solvent based nanofluids for energy transportation

Liquid range of nanofluids is a crucial parameter as it intensively determines their application temperature scope. Meanwhile, improved thermal conductivity and stability are of great significances and comprise the main fundamental research topics of nanofluids. In this work, 2- butoxy-3,4-dihydropyran (DP), produced from a convenient one-pot three-component reaction in water, was employed as dual lipophilic brusher and metal nanoparticle anchor. It was found that DP was able to enhance the dispersing ability and thermal conductivity of SiO2 nanoparticle filled deep eutectic solvent (DES) based nanofluids simultaneously. The key to the success of this protocol mainly relies on the electrophilic property and acetylacetonate moiety of DP, which ensures the formation of DP surficial modified and copper nanoparticle coated silica. Molecular dynamics simulation revealed that the hydrogen bonding effect between base solvent and alkane chain of nanoparticle was responsible for the enhanced affinity, which thus resulted in an improved stability. Viscosities of the nanofluids dropped within a certain range owing to the ruin of hydrogen bonding association among solvent molecules resulted by the hydrogen bonding effect between nanoparticle and solvent. Thermal conductivity of the copper modified silica filled DES nanofluids exhibits a maximum 13.6% enhancement, which demonstrated the advantages of this chemical covalent protocol. Additionally, study upon viscosity and convective heat transfer coefficient of the nanofluids with varies types of silica nanoparticle and DES base solvents indicated that a 24.9% heat transfer coefficient enhancement was gained that further revealed the superiority of this protocol

Novel Silica Filled Deep Eutectic Solvent Based Nanofluids for Energy Transportation

Liquid range of nanofluids is a crucial parameter as it intensively determines their application temperature scope. Meanwhile, improved thermal conductivity and stability are of great significances and comprise the main fundamental research topics of nanofluids. In this work, 2-butoxy-3,4-dihydropyran (DP), produced from a convenient one-pot three-component reaction in water, was employed as dual lipophilic brusher and metal nanoparticle anchor. It was found that DP was able to enhance the dispersing ability and thermal conductivity of SiO2 nanoparticle filled deep eutectic solvent (DES) based nanofluids simultaneously. The key to the success of this protocol mainly relies on the electrophilic property and acetylacetonate moiety of DP, which ensures the formation of DP surficial modified and copper nanoparticle coated silica. Molecular dynamics simulation revealed that the hydrogen bonding effect between base solvent and alkane chain of nanoparticle was responsible for the enhanced affinity, which thus resulted in an improved stability. Viscosities of the nanofluids dropped within a certain range owing to the ruin of hydrogen bonding association among solvent molecules resulted by the hydrogen bonding effect between nanoparticle and solvent. Thermal conductivity of the copper modified silica filled DES nanofluids exhibits a maximum 13.6% enhancement, which demonstrated the advantages of this chemical covalent protocol. Additionally, study upon viscosity and convective heat transfer coefficient of the nanofluids with varies types of silica nanoparticle and DES base solvents indicated that a 24.9% heat transfer coefficient enhancement was gained that further revealed the superiority of this protocol

Improvement of Printing Quality for Laser-induced Forward Transfer based Laser-Assisted Bioprinting Process using a CFD-based numerical model

As one of the three-dimensional (3D) bioprinting techniques with great application potential, laser-induced-forward-transfer (LIFT) based laser assisted bioprinting (LAB) transfers the bioink through a developed jet flow, and the printing quality highly depends on the stability of jet flow regime. To understand the connection between the jet flow and printing outcomes, a Computational Fluid Dynamic (CFD) model was developed for the first time to accurately describe the jet flow regime and provide a guidance for optimal printing process planning. By adopting the printing parameters recommended by the CFD model, the printing quality was greatly improved by forming stable jet regime and organized printing patterns on the substrate, and the size of printed droplet can also be accurately predicted through a static equilibrium model. The ultimate goal of this research is to direct the LIFT-based LAB process and eventually improve the quality of bioprinting

Experimental investigation of the flame retardant and form-stable composite phase change materials for a power battery thermal management system

© 2020 Elsevier Ltd. All rights reserved. This manuscript is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International Licence http://creativecommons.org/licenses/by-nc-nd/4.0/.An efficient battery thermal management system (BTMS) will undoubtedlypromote the performance and lifespan of battery packs. In this study, a novelflame-retarded composite PCMs composed by paraffin (PA), expanded graphite (EG), ammonium polyphosphate (APP), red phosphorus (RP) and epoxy resin (ER) has been proposed for battery module. The thermophysical and flame retardant properties are investigated at both macro and micro levels. The results show that the proposed composite PCMs with an APP/RP ratio of 23/10 exhibit the optimum flame retardant performance. Besides, the APP/RP-based composite PCMs for 18650 ternary battery module has also been researched comparing with air cooled and PCM with pure PA modes. The experimental results indicated that the fire retardant PCMs shown significant cooling and temperature balancing advantages for battery module, leading to a 44.7% and 30.1% reduction rate of the peak temperature and the maintenance of the maximum temperature difference within 1.36°C at a 3 C discharge rate for 25°C. Even at 45°C, the temperature uniformity can still be controlled within 5°C. Thus, this research indicates the composite PCM had good flame retardant and form stable properties, it would be utilized in BTMS, energy storage and other fields.Peer reviewe

Recent advances of nanofluids in micro/nano scale energy transportation

As the continuing integration and size deflation of component dimensions in electronic circuits and increase in the number of transistors in modern microprocessor chips, especially for heat dissipation of micro/nano scale devise, traditionally used single phase fluid cannot meet the requirements for highly efficient heat transfer, which thus frequently results in the damage of electrical devices. Consequently, thermal conductivity enhancement of working fluids is of great significance for advanced thermal energy conservation and conversion. Nanofluids, which possess a superior thermal conductive performance, are studied towards an alternative to the traditionally used working fluids, have attracted ample attention within the past decades. In this paper, firstly, we summarized the recent progress in the preparation of nanofluids, in particular for a method involving a covalent concerning reorganization or generation; subsequently, the utilization of nanofluids in hitherto unsummerized micro/nano scale heat and mass transfer fields, especially for some chemistry relating applications were discussed. All works demonstrated in this review are aiming at clarifying the fact that advanced material technologies are required in preparation of recent nanofluids on the premise of continuing harsh energy transfer situation; on the other hand, nanofluids were also able to offer insights for novel micro/nano scale energy transportation which has not yet been reviewed before

Genetic Deficiency of Glycogen Synthase Kinase-3β Corrects Diabetes in Mouse Models of Insulin Resistance

Despite treatment with agents that enhance β-cell function and insulin action, reduction in β-cell mass is relentless in patients with insulin resistance and type 2 diabetes mellitus. Insulin resistance is characterized by impaired signaling through the insulin/insulin receptor/insulin receptor substrate/PI-3K/Akt pathway, leading to elevation of negatively regulated substrates such as glycogen synthase kinase-3β (Gsk-3β). When elevated, this enzyme has antiproliferative and proapoptotic properties. In these studies, we designed experiments to determine the contribution of Gsk-3β to regulation of β-cell mass in two mouse models of insulin resistance. Mice lacking one allele of the insulin receptor (Ir+/−) exhibit insulin resistance and a doubling of β-cell mass. Crossing these mice with those having haploinsufficiency for Gsk-3β (Gsk-3β+/−) reduced insulin resistance by augmenting whole-body glucose disposal, and significantly reduced β-cell mass. In the second model, mice missing two alleles of the insulin receptor substrate 2 (Irs2−/−), like the Ir+/− mice, are insulin resistant, but develop profound β-cell loss, resulting in early diabetes. We found that islets from these mice had a 4-fold elevation of Gsk-3β activity associated with a marked reduction of β-cell proliferation and increased apoptosis. Irs2−/− mice crossed with Gsk-3β+/− mice preserved β-cell mass by reversing the negative effects on proliferation and apoptosis, preventing onset of diabetes. Previous studies had shown that islets of Irs2−/− mice had increased cyclin-dependent kinase inhibitor p27kip1 that was limiting for β-cell replication, and reduced Pdx1 levels associated with increased cell death. Preservation of β-cell mass in Gsk-3β+/−Irs2−/− mice was accompanied by suppressed p27kip1 levels and increased Pdx1 levels. To separate peripheral versus β-cell–specific effects of reduction of Gsk3β activity on preservation of β-cell mass, mice homozygous for a floxed Gsk-3β allele (Gsk-3F/F) were then crossed with rat insulin promoter-Cre (RIP-Cre) mice to produce β-cell–specific knockout of Gsk-3β (βGsk-3β−/−). Like Gsk-3β+/− mice, βGsk-3β−/− mice also prevented the diabetes of the Irs2−/− mice. The results of these studies now define a new, negatively regulated substrate of the insulin signaling pathway specifically within β-cells that when elevated, can impair replication and increase apoptosis, resulting in loss of β-cells and diabetes. These results thus form the rationale for developing agents to inhibit this enzyme in obese insulin-resistant individuals to preserve β-cells and prevent diabetes onset

Enhanced thermal performance of phase change material stabilized with textile-structured carbon scaffolds

The development of thermal conductive and porous supporting scaffolds is believed to solve the problems of poor shape-stability and low thermal conductivity of solid-liquid transition-type phase change materials (PCMs), which are promisingly used for solar thermal energy storage and management. In this paper, textile-structured carbon scaffolds with flexible shape and high porosity are produced by the direct carbonization of cotton cloth. The carbon textile with versatilely changeable shape can be employed as good conductive and supporting scaffolds for PCMs, and paraffin PCM is evaluated. The composite PCMs exhibit good shape-stability and enhanced thermal transfer properties. The composites can present anisotropically improved thermal conductivity by aligning the carbon sheets in their main yarn direction. The thermal conductivity of the composite with a carbon weight ratio of 16.5 wt% is increased to 0.99 W K-1 m(-1) from the main yarn direction and 0.68 W K-1 m(-1) from the through sheet direction, which is greatly higher than the value of paraffin (0.25 W k(-1) m(-1)), and the composite show heat capacity of 170 J g(-1). With the facile production of flexible and shapeable carbon supporting scaffold, the high thermal storage capability, good shape-stability and high heat transfer property, the composite PCM has great potential applications in solar thermal energy storage

A widely applicable strategy to convert fabrics into lithiophilic textile current collector for dendrite-free and high-rate capable lithium metal anode

Hindered by dendrite growth, unceasing volume change and repeated regeneration of solid-state electrolyte interface, the practical application of lithium (Li) metal anode is still facing challenges from low Coulombic efficiency (CE), insufficient safety performance and poor cyclic stability. Current collector plays a key role in regulating Li deposition and suppressing dendrite growth. In this report, through a simple bio-template method, a textile-structured nickel (Ni) framework is fabricated as current collector for Li metal anode, whose unique micro-nano hierarchical structure is adequate for accommodating Li. A good performance after more than 200 cycles at 3 mA cm(-2) during repeated Li plating/stripping is remained in virtue of this unique structure design. By further introducing Ag2S nanoparticles uniformly to the current collector, a dendrite-free and high reversible Li metal anode is achieved, showing low over-potential (similar to 24 mV at 1 mA cm(-2)), high CE (similar to 98%) and excellent quick charging/discharging stability (up to 350 cycles at 10 mA cm(-2) in symmetric cell). Furthermore, this new strategy for constructing textile-structured metallic framework opens a foreground for various applications of porous metals