Polyvinyl acetate/poly(amide-12-b-ethylene oxide) blend membranes for carbon dioxide separation

In this paper, blend membranes from polyvinyl acetate (PVAc) and block copolymer poly(amide-12-b-ethylene oxide) (Pebax1074) are prepared by solution casting and solvent evaporation method. Although they are homogeneous on a macro-scale, the observations from DSC and SEM indicate micro-phase separation for PVAc/Pebax1074 blend membranes. With the increase of Pebax1074 content, gas permeabilities of CO2, H-2, N-2 and CH4 all increase greatly. PVAc/Pebax1074 blend membranes with high PVAc content are appropriate for CO2/CH4 separation. The temperature dependence of gas permeability is divided into rubbery region and glassy region. The activation energies of permeation in rubbery region are smaller than those in glassy region, and they all decrease with increasing Pebax1074 content. For N-2, H-2 and CH4, their gas permeation properties are mainly influenced by the dual-mode sorption and hydrostatic pressure effect. But for CO2, its permeability increases with the increase of pressure due to CO2-induced plasticization effect, which is more obvious for PVAc/Pebax1074 blend membranes with high PVAc content

Adaptation of context-dependent deep neural networks for automatic speech recognition

In this paper, we evaluate the effectiveness of adaptation methods for context-dependent deep-neural-network hidden Markov models (CD-DNN-HMMs) for automatic speech recognition. We investigate the affine transformation and several of its variants for adapting the top hidden layer. We compare the affine transformations against direct adaptation of the softmax layer weights. The feature-space discriminative linear regression (fDLR) method with the affine transformations on the input layer is also evaluated. On a large vocabulary speech recognition task, a stochastic gradient ascent implementation of the fDLR and the top hidden layer adaptation is shown to reduce word error rates (WERs) by 17 % and 14%, respectively, compared to the baseline DNN performances. With a batch update implementation, the softmax layer adaptation technique reduces WERs by 10%. We observe that using bias shift performs as well as doing scaling plus bias shift

Poly(amide-12-b-ethylene oxide)/polyethylene glycol blend membranes for carbon dioxide separation

In this paper, block copolymer poly(amide-12-b-ethylene oxide) (Pebax1074)/poly(ethylene glycol) (PEG1500) blend membranes are prepared by solution casting and solvent evaporation method. According to DSC experiments, the melting temperature for PEO phase in Pebax1074/PEG1500 blend membranes increases with the increase of PEG1500 content, which will influence the gas transport properties. Compared with Pebax1074 membrane, the gas transport through Pebax1074/PEG1500 blend membranes can be divided into crystalline, transition and amorphous regions due to the temperature dependence of PEO thermal transition. And the gas permeability can be described by two different Arrhenius equations in crystalline and amorphous regions. For Pebax1074/PEG1500 blend membranes in crystalline region, the gas permeability is lower than that for Pebax1074 membrane, which decreases with the increasing PEG1500 content. But in amorphous region, the gas permeability is higher than that for Pebax1074 membrane, which also increases with the increasing PEG1500 content. For N-2, H-2 and CH4, the gas permeation behavior is mainly influenced by the hydrostatic pressure at high temperature, but for the polar gas CO2, it is dominated by CO2-induced plasticization effect and the hydrostatic pressure simultaneously. (c) 2013 Elsevier B.V. All rights reserved

CO2-philic polyether-block-amide/glycerol triacetate blend membranes: gas-permeation performance, thermal stability, and storage stability

Polyether-block-amide (Pebax)/glycerol triacetate (GTA) blend membranes with various compositions were prepared with a solution-casting method. The gas-separation performance, thermal stability, and storage stability of the prepared membranes were investigated at different pressures and temperatures. The Arrhenius equation was used to describe the gas-permeation performance of the Pebax1074/GTA membranes with a low GTA concentration (40 wt %). A higher GTA content, lower treatment temperature, and storage temperature increased the gas permeability and induced a stronger hydrostatic pressure effect. The low-storage temperature was beneficial for fixing GTA on the blend membrane. (c) 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47620

effectofpolyethyleneglycolmolecularweightonco2n2separationperformanceofpolyamide12bethyleneoxidepolyethyleneglycolblendmembranes

Membranes from block copolymer poly (amide-12-b-ethylene oxide) (pebax1074) and its blends with different molecular weight poly (ethylene glycol) (peg) (200, 400, 600, 1500, 4600 and 8000) were prepared. the thermal properties and structures of pebax1074/peg blend membranes were characterized by dsc and sem, and the gas permeation properties of co2 and n-2 were also investigated at different temperatures. for pebax1074/peg blend membranes with low molecular weight peg (m-w = 1500), due to the melt of peo phase crystals, the gas permeation properties of blend membranes were temperature-dependent, which could be divided into crystalline region, transition region and amorphous region according to two different transition temperatures. peg molecular weight and operation temperature determined different gas permeation properties of pebax1074/peg blend membranes in three regions. the activation energies of permeation in crystalline region were larger than those in amorphous region. (c) 2017 science press and dalian institute of chemical physics, chinese academy of sciences. published by elsevier b.v. and science press. all rights reserved

Effect of poly(ethylene glycol) molecular weight on CO2/N-2 separation performance of poly(amide-12-b-ethylene oxide)/poly(ethylene glycol) blend membranes

Membranes from block copolymer poly (amide-12-b-ethylene oxide) (Pebax1074) and its blends with different molecular weight poly (ethylene glycol) (PEG) (200, 400, 600, 1500, 4600 and 8000) were prepared. The thermal properties and structures of Pebax1074/PEG blend membranes were characterized by DSC and SEM, and the gas permeation properties of CO2 and N-2 were also investigated at different temperatures. For Pebax1074/PEG blend membranes with low molecular weight PEG (M-w = 1500), due to the melt of PEO phase crystals, the gas permeation properties of blend membranes were temperature-dependent, which could be divided into crystalline region, transition region and amorphous region according to two different transition temperatures. PEG molecular weight and operation temperature determined different gas permeation properties of Pebax1074/PEG blend membranes in three regions. The activation energies of permeation in crystalline region were larger than those in amorphous region. (C) 2017 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved

Trajectories network analysis of chronic diseases among middle-aged and older adults: evidence from the China Health and Retirement Longitudinal Study (CHARLS)

Abstract Background Given the increased risk of chronic diseases and comorbidity among middle-aged and older adults in China, it is pivotal to identify the disease trajectory of developing chronic multimorbidity and address the temporal correlation among chronic diseases. Method The data of 15895 participants from the China Health and Retirement Longitudinal Study (CHARLS 2011 – 2018) were analyzed in the current study. Binomial tests and the conditional logistic regression model were conducted to estimate the associations among 14 chronic diseases, and the disease trajectory network analysis was adopted to visualize the relationships. Results The analysis showed that hypertension is the most prevalent disease among the 14 chronic conditions, with the highest cumulative incidence among all chronic diseases. In the disease trajectory network, arthritis was found to be the starting point, and digestive diseases, hypertension, heart diseases, and dyslipidemia were at the center, while memory-related disease (MRD), stroke, and diabetes were at the periphery of the network. Conclusions With the chronic disease trajectory network analysis, we found that arthritis was prone to the occurrence and development of various other diseases. In addition, patients of heart diseases/hypertension/digestive disease/dyslipidemia were under higher risk of developing other chronic conditions. For patients with multimorbidity, early prevention can preclude them from developing into poorer conditions, such as stroke, MRD, and diabetes. By identifying the trajectory network of chronic disease, the results provided critical insights for developing early prevention and individualized support services to reduce disease burden and improve patients’ quality of life

Blend membranes of poly(amide-6-b-ethylene oxide)/[Emim][PF6] for CO2 separation

1-Ethyl-3-methylimidazolium hexafluorophosphate ([Emim][PF6]) was incorporated into poly(amide-6-b-ethylene oxide) (Pebax1657) to prepare blend membranes. The physical properties of Pebax1657/[Emim][PF6] blend membranes were characterized by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). For Pebax1657/[Emim] [PF6] blend membranes, the melting peak of polyether (PE) segment disappeared when [Emim][PF6] content reached 10 wt%, and the melting peak of [Emim][PF6] appeared until [Emim][PF6] content came up to 60 wt%, indicating the homogeneous mixing of [Emim][PF6] and Pebax1657 for the prepared Pebax1657/ [Emim][PF6] blend membranes. According to FTIR, some interactions were formed between [Emim][PF6] and PE segment. The gas transport properties of CO2, N-2, CH4 and H-2 for Pebax1657/[Emim][PF6] blend membranes were also investigated. The incorporation of [Emim][PF6] increased the gas solubility coefficients of CO2, N-2, CH4 and H-2, however the gas diffusion coefficients decreased, which led to the decrease of the permeabilities of CO2, N-2, CH4 and H-2. Meanwhile, the selectivity of CO2/CH4 increased slightly. With the increase of temperature (35-85 degrees C), the solubility coefficient of CO2 decreased, while the diffusion coefficients of CO2, N-2, CH4 and H-2 increased, resulting into the increase of the permeabilities of CO2, N-2, CH4 and H-2. Moreover, no sharp increase of gas permeability was observed at the melting point of [Emim][PF6] (60 degrees C). And the activation energies of permeation of CO2, N-2, CH4 and H-2 increased with increasing [Emim][PF6] content. (C) 2017 Elsevier B.V. All rights reserved

Additional file 1 of Trajectories network analysis of chronic diseases among middle-aged and older adults: evidence from the China Health and Retirement Longitudinal Study (CHARLS)

Additional file 1: Supplementary Table 1. Results of the binomial test. Supplementary Table 2. Characteristics of Population. Fig S1. The median and IQR of onset age of individual’s first chronic diseases by gender. Fig S2. Cumulative rate of 14 chronic diseases. Fig S3. Age distribution of the onset of 14 diseases by gender