Investigation of equilibrium and dynamic performance of SrCl2-expanded graphite composite in chemisorption refrigeration system

This work experimentally investigated adsorption equilibrium and reaction kinetics of ammonia adsorption/desorption on the composite of strontium chloride (SrCl2) impregnated into expanded graphite, and also discussed the potential influence of the addition of expanded graphite on the SrCl2-NH3 reaction characteristics. The measured and analysed results can be very useful information to design the system and operating conditions using the similar chemisorption composites. Equilibrium concentration characteristics of ammonia within the studied composite were measured using the heat sources at 90 °C, 100 °C and 110 °C for the decomposition process, where the degree of conversion achieved 50%, 78% and 96% respectively. Therefore, the equilibrium equation reflecting the relationship between temperature, pressure and concentration was developed, and a pseudo-equilibrium zone was found, which should be useful information to setup the system operating condition for the desired global transformation. It was suspected that the addition of expanded graphite altered the reaction equilibrium due to the pore effect and the salt-confinement. The concept of two-stage kinetic model was proposed and kinetic parameters were determined by fitting experimental data. The developed kinetic equations can predict dynamic cyclic performance of a reactive bed in similar geometric structure with reasonable accuracy. Such a chemisorption cycle using the SrCl2-expnaded graphite (mass ratio 2:1) composite can be used for cooling application, and the maximum SCP value can be achieved as high as 656 W/kg at t = 2.5 min, and the COP can be 0.3 after one hour of synthesis process under the condition of Tev = 0 °C, Tcon = 20 °C, Theat = 110 °C

MicroRNA and transcription factor co-regulatory network analysis reveals miR-19 inhibits CYLD in T-cell acute lymphoblastic leukemia

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematological malignancy. The understanding of its gene expression regulation and molecular mechanisms still remains elusive. Started from experimentally verified T-ALL-related miRNAs and genes, we obtained 120 feed-forward loops (FFLs) among T-ALL-related genes, miRNAs and TFs through combining target prediction. Afterwards, a T-ALL miRNA and TF co-regulatory network was constructed, and its significance was tested by statistical methods. Four miRNAs in the miR-17–92 cluster and four important genes (CYLD, HOXA9, BCL2L11 and RUNX1) were found as hubs in the network. Particularly, we found that miR-19 was highly expressed in T-ALL patients and cell lines. Ectopic expression of miR-19 represses CYLD expression, while miR-19 inhibitor treatment induces CYLD protein expression and decreases NF-κB expression in the downstream signaling pathway. Thus, miR-19, CYLD and NF-κB form a regulatory FFL, which provides new clues for sustained activation of NF-κB in T-ALL. Taken together, we provided the first miRNA-TF co-regulatory network in T-ALL and proposed a model to demonstrate the roles of miR-19 and CYLD in the T-cell leukemogenesis. This study may provide potential therapeutic targets for T-ALL and shed light on combining bioinformatics with experiments in the research of complex diseases

Field study on energy economic assessment of office buildings envelope retrofitting in southern China

Energy consumption of buildings accounts for more than 37.3% of total energy consumption while the proportion of energy-saving buildings is just 5% in China. In this paper, in order to save potential energy, the building envelope retrofitting is considered. An office building in Southern China was selected as a test example for energy consumption characteristics. The base building model was developed by TRNSYS software and validated against the recorded data from the field work in six days out of August-September in 2013. In addition, with a design of numerical simulation, sensitivity analysis was conducted for energy performance of building envelope retrofitting; six envelope parameters were analyzed for assessing the thermal responses. Results show that significant energy savings are obtained for the thermal transmittance (U-value) of exterior walls, infiltration rate, ventilation and shading coefficient, of which the sum relative sensitivity is about 91.06%. The results are evaluated in terms of energy and economic analysis. On the other hand, it appears that the cost-effective method improves the efficiency of investment management in building energy. (C) 2016 Elsevier Ltd. All rights reserved

Material symmetry recognition and property prediction accomplished by crystal capsule representation

Abstract Learning the global crystal symmetry and interpreting the equivariant information is crucial for accurately predicting material properties, yet remains to be fully accomplished by existing algorithms based on convolution networks. To overcome this challenge, here we develop a machine learning (ML) model, named symmetry-enhanced equivariance network (SEN), to build material representation with joint structure-chemical patterns, to encode important clusters embedded in the crystal structure, and to learn pattern equivariance in different scales via capsule transformers. Quantitative analyses of the intermediate matrices demonstrate that the intrinsic crystal symmetries and interactions between clusters have been exactly perceived by the SEN model and critically affect the prediction performances by reducing effective feature space. The mean absolute errors (MAEs) of 0.181 eV and 0.0161 eV/atom are obtained for predicting bandgap and formation energy in the MatBench dataset. The general and interpretable SEN model reveals the potential to design ML models by implicitly encoding feature relationship based on physical mechanisms

Analysis of an optimal resorption cogeneration using mass and heat recovery processes

This paper presents an optimised resorption cogeneration using mass and heat recovery to improve the performance of a novel resorption cogeneration fist proposed by Wang et al. This system combines ammonia-resorption technology and expansion machine into one loop, which is able to generate refrigeration and electricity from low-grade heat sources such as solar energy and industrial waste heat. Two sets of resorption cycle are designed to overcome the intermittent performance of the chemisorption and produce continuous/simultaneous refrigeration and electricity. In this paper, twelve resorption working pairs of salt complex candidates are analysed by the first law analysis using Engineering Equation Solver (EES). The optimal resorption working pairs from the twelve candidates under the driven temperature from 100 °C to 300 °C are identified. By applying heat/mass recovery, the coefficient of performance (COP) improvement is increased by 38% when the high temperature salt (HTS) is NiCl2 and by 35% when the HTS is MnCl2. On the other hand, the energy efficiency of electricity has also been improved from 8% to 12% with the help of heat/mass recovery. The second law analysis has also been applied to investigate the exergy utilisation and identify the key components/processes. The highest second law efficiency is achieved as high as 41% by the resorption working pair BaCl2–MnCl2 under the heat source temperature at 110 °C

Optimisation of a Novel Resorption Cogeneration Using Mass and Heat Recovery

AbstractThe paper proposed an optimised resorption cogeneration with a stabilisation unit and effective mass and heat recovery to further improve the performance of the original resorption cogeneration first proposed by Liwei Wang et al. It combines the ammonia resorption technology and expansion machine to utilise low grade heat such as solar energy or waste heat for continuous and simultaneous production of refrigeration and electricity. It has been theoretically proved competent to improve the overall exergy efficiency by 40%-60% compared with Goswami cycle under the same working conditions. In this work, a buffer was designed to place before the expansion machine to mitigate the dramatically varying reaction rate, and two sets of resorption cycle were arranged to overcome the intermittent performance of the chemisorption. The cycle was investigated based on the first and second law of thermodynamics using Engineering Equation Solver. Twelve resorption working pairs of salt complex candidates were analysed under different working conditions. The energy and exergy analysis identified the ideal working pair among the chosen working pairs under the driven temperature from 373K to 473K

Investigation of a Heat Pipe Heat Exchanger Integrated with a Water Spray for the Heat Recovery from Boil Exhaust Gas

AbstractThis paper presents a thermodynamic analysis and a numerical simulation of a heat pipe heat exchanger which recovers both sensible and latent heat from the exhaust gases of boiler with a temperature range from 450K to 600K. Compared with the conventional methods of preventing corrosion by avoiding acid dew point or using the anticorrosive material, a water spray is proposed in this work as an innovation to integrate with the heat pipe heat exchanger, which absorbs the corrosive gas such as SO2, SO3 and NOx from the outlet of boiler. The comprehensive theoretical study has shown the convective heat transfer coefficient under wet condition is 1.5-3 times higher than that of dry condition and the optimal location of the water spray in the system has been identified. Meanwhile a the heat and mass transfer in a thirty-row heat pipe heat exchanger with different locations of a water spray has been established by the FLUENT to analyze the flow field and temperature gradient of the heat pipe heat exchanger. The overall analysis has proven that system efficiency of the boiler and the lifetime of heat exchanger can be effectively enhanced with the application of the water spray

Optimisation of a Novel Resorption Cogeneration Using Mass and Heat Recovery

AbstractThe paper proposed an optimised resorption cogeneration with a stabilisation unit and effective mass and heat recovery to further improve the performance of the original resorption cogeneration first proposed by Liwei Wang et al. It combines the ammonia resorption technology and expansion machine to utilise low grade heat such as solar energy or waste heat for continuous and simultaneous production of refrigeration and electricity. It has been theoretically proved competent to improve the overall exergy efficiency by 40%-60% compared with Goswami cycle under the same working conditions. In this work, a buffer was designed to place before the expansion machine to mitigate the dramatically varying reaction rate, and two sets of resorption cycle were arranged to overcome the intermittent performance of the chemisorption. The cycle was investigated based on the first and second law of thermodynamics using Engineering Equation Solver. Twelve resorption working pairs of salt complex candidates were analysed under different working conditions. The energy and exergy analysis identified the ideal working pair among the chosen working pairs under the driven temperature from 373K to 473K