Paraffin core-polymer shell micro-encapsulated phase change materials and expanded graphite particles as an enhanced energy storage medium in heat exchangers

The Micro-Encapsulated Phase Change Materials (MEPCMs) with the melting point temperature of 28 °C was used as an energy storage medium to control the thermal behaviour of a heat exchanger. The NEPCM particles were mixed with Expanded Graphite (EG) microparticles to improve the heat transfer rate in the heat exchanger. The MEPCM particles are made of paraffin cores with a particle average size of 45 μm. The paraffin core of the particles can undergo a solid/liquid phase change and store a tremendous amount of thermal energy due to the latent heat of phase change. The heat exchanger is a copper pipe radiator with aluminium fins confined in either a bed of MEPCMs or a composite mixture of MEPCMs + Expanded Graphite (EG) microparticles. The thermophysical properties of MEPCMs and MEPCM + EG were measured. The outcomes show 132% enhancement in thermal conductivity and a 28% decrease in the sensible specific heat of the MEPCM + EG composite with the weight ratio of 70% MEPCM and 30% EG compared to pure MEPCM. The charging and discharging behaviour of heat exchanger for various flow rates and two cases of MEPCM and MEPCM + EG were studied experimentally. The results reveal that using EG notably enhances the heat transfer and capability of the heat exchanger during the charging and discharging process. Using MEPCM + EG reduces the temperature drop at the heat exchanger outlet about 15 °C compared to the case of pure MEPCM.     

丙烯腈/丙烯酸甲酯与相变微胶囊共混物薄片的制备及性能表征

采用水相沉淀聚合法制备相变材料微胶囊质量分数为0%～25%的丙烯腈/丙烯酸甲酯共聚物的混合物,经熔融压制成厚度为1 mm的薄片;分别采用差示扫描量热分析仪(DSC)、X-射线衍射分析仪(XRD)、动态热机械性能(DMA)和扫描电子显微镜观察(SEM)对混合物薄片的结构和性能等进行分析测试.结果表明:相变材料微胶囊的加入使混合物薄片的玻璃化转变温度升高,薄片的熔融焓和结晶焓随微胶囊含量的增加而增大.     

热塑性聚氨酯/微胶囊化聚磷酸铵/氢氧化铝复合材料的制备及性能研究

通过溶胶?凝胶法制备了硅凝胶微胶囊化聚磷酸铵（MAPP）,并通过红外光谱仪（FTIR）、热重分析仪（TG）对MAPP进行了表征;采用熔融共混技术将氢氧化铝（ATH）和MAPP加入到热塑性聚氨酯弹性体（TPU）中,制备出系列阻燃热塑性聚氨酯弹性体（TPU/FR）复合材料,并通过TG、微型量热计（MCC）研究了TPU/FR的热稳定性和燃烧行为。结果表明,在ATH与MAPP总含量为20 %（质量分数,下同）的情况下,相对于TPU/FR1（20 % ATH）复合材料,ATH与MAPP含量分别为5 %、15 %,10 %、10 %和15 %、5 %的TPU/FR复合材料在700 oC下的残炭量分别由16.7 %提高到29.7 %、25.1 %和20.9 %;热释放容量（HRC）分别从327.1 J/（g·K）降低到154.2、164.2和170.1 J/（g·K）;对比TPU/FR2（20 % MAPP）复合材料,TPU/FR4（15 % ATH,5 % MAPP）炭渣的致密性和石墨化程度显著提高,表明ATH与MAPP复合具有显著的阻燃协同作用。     

Arginase 2 and Polyamines in Human Pancreatic Beta Cells: Possible Role in the Pathogenesis of Type 2 Diabetes

Arginase 2 (ARG2) is a manganese metalloenzyme involved in several tissue specific processes, from physiology to pathophysiology. It is variably expressed in extra-hepatic tissues and is located in the mitochondria. In human pancreatic beta cells, ARG2 is downregulated in type 2 diabetes. The enzyme regulates the synthesis of polyamines, that are involved in pancreas development and regulation of beta cell function. Here, we discuss several features of ARG2 and polyamines, which can be relevant to the pathophysiology of type 2 diabetes.     

微胶囊固定化培养重组盘基网柄菌提高人类可溶性Fas配体的表达

首先研究了应用于液芯羧甲基纤维素钠-海藻酸钙(CMC-ALG)微胶囊制备中的各种化学组分对重组盘基网柄菌生长的影响,然后考察不同组分浓度制备而成的各种CMC-ALG微胶囊内重组盘基网柄菌的生长情况,从而得到较适的微胶囊制备的组分配比(CMC 12 g·L-1,SA 8 g·L-1,CaCl2 100 g·L-1).结果表明,在以上较适条件下制备的微胶囊内重组盘基网柄菌的生长得到了极大的改善,最大的细胞密度比游离培养时提高了4倍,达到了8.0×107 mL-1;相应的人类可溶性Fas配体(FasL)的表达水平也提高了1.5倍,达到了315 μg·L-1.最后,开展了微胶囊化重组盘基网柄菌的二次重复发酵FasL的研究,结果表明,经过二次重复批次培养,最大细胞密度可达到1.24×108 mL-1,为游离培养的8～10倍,而且FasL的表达水平还能维持高水平(280 μg·L-1),为游离培养时的2倍.     

Flow frictional characteristics of microencapsulated phase change material suspensions flowing through rectangular minichannels

1 Introduction MEPCM, i.e. microencapsulated phase change material, is formed as shown in Fig. 1 by packing phase change material (PCM) into a microcapsule with a solid but flexible shell; the size of the MEPCM particles ranges from 1 to 100 μm[1,2]. The shell separates the core PCM (solid or liquid) from outside substances and tolerates volume changes in the core due to phase change. Widespread applications of MEPCM include: enhancing performance of fluid convective heat transfer, te…     

月见草油微胶囊粉末油脂中油脂过氧化值测定之提油方法的研究

为测定月见草油微胶囊粉末油脂中油脂过氧化值,比较了碱性乙醚法、机械研磨法、超声波振荡法提油的优劣,结果表明:碱性乙醚法提油率虽高(94.69%),但测得的POV值与原料油相比偏高很多,明显失真;机械研磨法提油率偏低(40.68%),且不稳定,不宜采用;超声波振荡法提油率居中(59.63%),重现性好,精确度高,POV测定值与原料油最接近;试验还表明超声振荡时间以3min为宜。     

相变材料在建筑中的应用

相变材料是一种高效的贮热物质。在一定的温度下，它发生相变，并伴随着吸热、放热。根据相变材料化学成分、相变过程形态和相变温度，相变材料可以分为不同的种类。相变材料结合微胶囊技术制造的相变材料微胶囊具有导热系数好，易于与建筑材料结合，经济等优点。本文介绍了相变材料在墙体、混凝土制品、地板中的应用，以达到节能和室内舒适的目的，并指出了今后还需要进一步研究的一些问题。     

圆管内对流换热过程中潜热型功能流体流动阻力特性的实验研究

实验研究了由正十四烷和尿素甲醛树脂制成的相变微胶囊和水混合制成的潜热型功能流体在流过恒热流圆管进行对流换热时的流动阻力特性,获得了压降随流速的变化关系、摩擦阻力系数和表观黏度随R e的变化关系。并在同样条件下用单相水进行了对比实验。相变微胶囊的加入导致流体流动阻力较单相流体有显著增大。管路中扰动件导致单相流体的流动阻力特性在低R e条件下呈湍流特征;功能流体则呈不同规律,扰动仅导致流动阻力进一步增大,而流动阻力特性仍呈层流特征。     

Integrated Metabolomics and Proteomics Analyses in the Local Milieu of Islet Allografts in Rejection versus Tolerance

An understanding of the immune mechanisms that lead to rejection versus tolerance of allogeneic pancreatic islet grafts is of paramount importance, as it facilitates the development of innovative methods to improve the transplant outcome. Here, we used our established intraocular islet transplant model to gain novel insight into changes in the local metabolome and proteome within the islet allograft’s immediate microenvironment in association with immune-mediated rejection or tolerance. We performed integrated metabolomics and proteomics analyses in aqueous humor samples representative of the graft’s microenvironment under each transplant outcome. The results showed that several free amino acids, small primary amines, and soluble proteins related to the Warburg effect were upregulated or downregulated in association with either outcome. In general, the observed shifts in the local metabolite and protein profiles in association with rejection were consistent with established pro-inflammatory metabolic pathways and those observed in association with tolerance were immune regulatory. Taken together, the current findings further support the potential of metabolic reprogramming of immune cells towards immune regulation through targeted pharmacological and dietary interventions against specific metabolic pathways that promote the Warburg effect to prevent the rejection of transplanted islets and promote their immune tolerance.