Search

Real-time and accurate travel time information between bus stations is critical for passengers to make suitable travel plans to reduce waiting time at the stops. By mining and analyzing bus operational data, it can be obtained that factors such as the variation of vehicle speed in adjacent sections and the proportion of bus lanes between stations have affected the travel time between bus stations. Therefore, considering the temporal feature, spatial feature, and weather feature as the prediction model’s input, travel time between bus stations prediction model based on eXtreme Gradient Boosting (XGBoost) was trained and established. The 28-day bus operation data of a certain bus line in Guangzhou was used for training and verification, and they were compared with the prediction models based on K -Nearest Neighbors (KNN), BP neural network, and Light Gradient Boosting Machine (LightGBM). In comparison with other models, the lowest MAPE of 11.96% was found for the XGBoost prediction model, which is 9.30% lower than other models on average. The sensitivity analysis of the proposed prediction model was further conducted: temporally, the accuracy of the prediction model was best during the flat peak hours; spatially, the MAPE of the model gradually decreased as the number of line units increased, and when the number of line units exceeded 18, the accuracy of the prediction model stabilized and was lower than 7%. The results confirm that the XGBoost model outperforms the KNN, BP, and LightGBM in terms of fitting, accuracy, and stability.

In the actual operation of a bus, due to the influences of the passenger flow, traffic conditions and other factors, the vehicle back-station time is often delayed, which brings difficulties in commuting according to a timetable that results in the discontinuity of the bus. This is also the main disadvantage of static bus scheduling. Therefore, the “Entropy model of dynamic bus dispatching based on the prediction of back-station time” is proposed, which can be used for decreasing the passive effect of discontinuity by extending the departure interval of an early bus in advance, and to realize fairness in adjustments of the departure interval by using entropy theory. Finally, the model is validated by two examples, and the results show that the model can match the distribution pattern of the bus departure interval before and after an adjustment and as far as possible, it can reduce bus breaks, balance the occupancy rate and improve the stability of bus operations.

Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disease characterized by the degeneration of motor neurons and progressive muscle atrophy. Accurate detection of

Nanoporous silica membranes exhibit excellent H2/CO2 separation properties for sustainable H2 production and CO2 capture but are prepared via complicated thermal processes above 400 °C, which prevent their scalable production at a low cost. Here, we demonstrate the rapid fabrication (within 2 min) of ultrathin silica-like membranes (∼3 nm) via an oxygen plasma treatment of polydimethylsiloxane-based thin-film composite membranes at 20 °C. The resulting organosilica membranes unexpectedly exhibit H2 permeance of 280-930 GPU (1 GPU = 3.347 × 10-10 mol m-2 s-1 Pa-1) and H2/CO2 selectivity of 93-32 at 200 °C, far surpassing state-of-the-art membranes and Robeson's upper bound for H2/CO2 separation. When challenged with a 3 d simulated syngas test containing water vapor at 200 °C and a 340 d stability test, the membrane shows durable separation performance and excellent hydrothermal stability. The robust H2/CO2 separation properties coupled with excellent scalability demonstrate the great potential of these organosilica membranes for economic H2 production with minimal carbon emissions.

The walking time in metro stations is influenced by passenger flow with large fluctuation. Therefore, this paper proposes a method of station walking time calculation considering the influence of passenger flow: firstly, the time, entry, and exit direction and volume distribution characteristics of station passenger flow are analyzed, and the threshold of passenger flow that affects walking time is defined; then, an entry and exit walking time calculation model is established by five independent travel time chains and three station walking time constraints, and the transfer walking time is calculated based on the entry and exit walking time results; finally, the accuracy and validity of the walking time projection model are verified by using the calculation results. The results show that the calculation results are accurate and the validity of the model reaches 91.5%, and the constraint effect on walking time at station time is most obvious when the passenger flow reaches 3000 passengers per 30 min.

MOF-based mixed-matrix membranes (MMMs) have attracted considerable attention due to their tremendous separation performance and facile processability. In large-scale applications such as CO2 separation from flue gas, it is necessary to have high gas permeance, which can be achieved using thin membranes. However, there are only a handful of MOF MMMs that are fabricated in the form of thin-film composite (TFC) membranes. We propose herein the fabrication of robust thin-film composite mixed-matrix membranes (TFC MMMs) using a three dimensional (3D) printing technique with a thickness of 2–3 μm. We systematically studied the effect of casting concentration and number of electrospray cycles on membrane thickness and CO2 separation performance. Using a low concentration of polymer of intrinsic microporosity (PIM-1) or PIM-1/HKUST-1 solution (0.1 wt%) leads to TFC membranes with a thickness of less than 500 nm, but the fabricated membranes showed poor CO2/N2 selectivity, which could be attributed to microscopic defects. To avoid these microscale defects, we increased the concentration of the casting solution to 0.5 wt% resulting in TFC MMMs with a thickness of 2–3 μm which showed three times higher CO2 permeance than the neat PIM-1 membrane. These membranes represent the first examples of 3D printed TFC MMMs using the electrospray printing technique.

Circulating tumor DNA (ctDNA)-based mutation detection is promising to change the clinical practice of genotype-directed therapy for cancer. A growing number of non-invasive tests for cancer screening and monitoring that involve the detection of ctDNA have been commercialized. Primary reference measurement procedures (PRMPs) and reference materials (RMs) are urgently needed to assess the non-invasive tests. In this study, a PRMP based on digital PCR (dPCR) and ctDNA RMs for quantification of the frequently occurring variant in epidermal growth factor receptor (EGFR L858R, T790M, and 19Del) in non-small cell lung cancer (NSCLC) were established. The candidate dPCR PRMP showed high specificity (false positive rate 0-0.003%), good repeatability (coefficient of variance (CV), 2-3% for 104 copies/reaction), and high interlaboratory reproducibility (3-10%). A good linearity (0.97 < slope < 1.03, R2 ≥ 0.9999) between the measured mutant (MU) value and prepared value was observed for all assays over the fractional abundance (FA) range, between 25% and 0.05%. The limit of quantification (LoQ) was determined to be 34 L858R, 23 T790M, and 34 19Del copies/reaction, corresponding to a FA of 0.2%. An inter-laboratory study of using the EGFR ctDNA RMs and dPCR assays demonstrated that the participating laboratories produced consistent concentrations of MU and wild-type (WT), as well as FA. This study demonstrates that dPCR can act as a potential PRMP for EGFR mutation for validation of NSCLC genotyping tests and ctDNA quantitative tests. The PRMP and RMs established here could improve interlaboratory repeatability and reproducibility, which supports rapid translation and application of non-invasive tests into clinical practice.

BACKGROUND Accurate detection of anaplastic lymphoma kinase (ALK) rearrangement is the prerequisite for anti-ALK therapy for the patient with non-small cell lung cancer (NSCLC). Fusion-induced asymmetric transcription assay (FIATA)-based reverse transcription droplet digital PCR (RT-ddPCR) was developed and performed for ALK status survey in NSCLC samples. METHODS A total of 269 cases of formalin-fixed paraffin-embedded (FFPE) specimens from NSCLC, in which ALK status was confirmed by both fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC), were analyzed by FIATA-based RT-ddPCR. RESULTS In the ALK-positive group, the 3' ALK transcript copies range was 336.6-107 955.4, and the R3 [(the ratio of the 3' ALK transcript copy numbers to the internal reference gene transcript copy numbers) × 100] was 17.23-672.77. In the ALK-negative group, the 3' ALK transcript copies range was 3.7-1370.6, and the R3 range was 0.10-15.57. The lowest R3 level in the ALK-positive group was significantly higher than the highest R3 level in the ALK-negative group. A positive correlation between the proportion of cancer cells in the tissue section and ALK RNA expression level (R3) was found (P

An effective cross-linking technique allows a viscous and highly gas-permeable hydrophilic polyphosphazene to be cast as solid membrane films. By judicious blending with other polyphosphazenes to improve the mechanical properties, a membrane exhibiting the highest CO2 permeability (610 barrer) among polyphosphazenes combined with a good CO2/N2 selectivity (35) was synthesized and described here. The material demonstrates performance stability after 500 h of exposure to a coal-fired power plant flue gas, making it attractive for use in carbon capture applications. Its CO2/N2 selectivity under conditions up to full humidity is also stable, and although the gas permeability does decline, the performance is fully recovered upon drying. The high molecular weight of these heteropolymers also allows them to be cast as a thin selective layer on an asymmetric porous membrane, yielding a CO2 permeance of 1200 GPU and a CO2/N2 pure gas selectivity of 31, which does not decline over 2000 h. In addition to gas separation membranes, this cross-linked polyphosphazene can potentially be extended to other applications, such as drug delivery or proton exchange membranes, which take advantage of the polyphosphazene's versatile chemistry.

Most examples of mixed-matrix membranes (MMMs) involve one type of polymer and one type of inorganic filler particle. Here, both polymer blending and MMM approaches are combined to form exceptional...

Background Coronavirus disease 2019 (COVID-19) has become a public health emergency. The widely used reverse transcription–polymerase chain reaction (RT-PCR) method has limitations for clinical diagnosis and treatment. Methods A total of 323 samples from 76 COVID-19–confirmed patients were analyzed by droplet digital PCR (ddPCR) and RT-PCR based 2 target genes (ORF1ab and N). Nasal swabs, throat swabs, sputum, blood, and urine were collected. Clinical and imaging data were obtained for clinical staging. Results In 95 samples that tested positive by both methods, the cycle threshold (Ct) of RT-PCR was highly correlated with the copy number of ddPCR (ORF1ab gene, R2 = 0.83; N gene, R2 = 0.87). Four (4/161) negative and 41 (41/67) single-gene positive samples tested by RT-PCR were positive according to ddPCR with viral loads ranging from 11.1 to 123.2 copies/test. The viral load of respiratory samples was then compared and the average viral load in sputum (17 429 ± 6920 copies/test) was found to be significantly higher than in throat swabs (2552 ± 1965 copies/test, P Conclusions Quantitative monitoring of viral load in lower respiratory tract samples helps to evaluate disease progression, especially in cases of low viral load.

Graphical abstract The pandemic of the novel coronavirus disease 2019 (COVID-19) has caused severe harm to the health of people all around the world. Molecular detection of the pathogen, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), played a crucial role in the control of the disease. Reverse transcription digital PCR (RT-dPCR) has been developed and used in the detection of SARS-CoV-2 RNA as an absolute quantification method. Here, an interlaboratory assessment of quantification of SARS-CoV-2 RNA was organized by the National Institute of Metrology, China (NIMC), using in vitro transcribed RNA samples, among ten laboratories on six different dPCR platforms. Copy number concentrations of three genes of SARS-CoV-2 were measured by all participants. Consistent results were obtained with dispersion within 2.2-fold and CV% below 23% among different dPCR platforms and laboratories, and Z′ scores of all the reported results being satisfactory. Possible reasons for the dispersion included PCR assays, partition volume, and reverse transcription conditions. This study demonstrated the comparability and applicability of RT-dPCR method for quantification of SARS-CoV-2 RNA and showed the capability of the participating laboratories at SARS-CoV-2 test by RT-dPCR platform. Supplementary Information The online version contains supplementary material available at 10.1007/s00216-021-03680-2.

Circulating tumor DNA (ctDNA)-based mutation detection is promising to change the clinical practice of genotype-directed therapy for cancer. A growing number of non-invasive tests for cancer screening and monitoring that involve the detection of ctDNA have been commercialized. Primary reference measurement procedures (PRMPs) and reference materials (RMs) are urgently needed to assess the non-invasive tests. In this study, a PRMP based on digital PCR (dPCR) and ctDNA RMs for quantification of the frequently occurring variant in epidermal growth factor receptor (EGFR L858R, T790M, and 19Del) in non-small cell lung cancer (NSCLC) were established. The candidate dPCR PRMP showed high specificity (false positive rate 0-0.003%), good repeatability (coefficient of variance (CV), 2-3% for 104 copies/reaction), and high interlaboratory reproducibility (3-10%). A good linearity (0.97slope1.03, R2 ≥ 0.9999) between the measured mutant (MU) value and prepared value was observed for all assays over the fractional abundance (FA) range, between 25% and 0.05%. The limit of quantification (LoQ) was determined to be 34 L858R, 23 T790M, and 34 19Del copies/reaction, corresponding to a FA of 0.2%. An inter-laboratory study of using the EGFR ctDNA RMs and dPCR assays demonstrated that the participating laboratories produced consistent concentrations of MU and wild-type (WT), as well as FA. This study demonstrates that dPCR can act as a potential PRMP for EGFR mutation for validation of NSCLC genotyping tests and ctDNA quantitative tests. The PRMP and RMs established here could improve interlaboratory repeatability and reproducibility, which supports rapid translation and application of non-invasive tests into clinical practice.

Nanoporous silica membranes exhibit excellent H2/CO2 separation properties for sustainable H2 production and CO2 capture but are prepared via complicated thermal processes above 400 oC, which prevent their scalable production at low cost. Here, we demonstrate the rapid fabrication (within 6 minutes) of ultrathin silica membranes (≈6 nm) via oxygen plasma treatment of polydimethylsiloxane based thin-film composite membranes at 20 oC. The resulting organosilica membranes exhibit H2 permeance of 280 - 930 GPU (1 GPU = 3.347×10-10 mol m-2 s-1 Pa-1) and H2/CO2 selectivity of 93 - 32 at 200 °C, far surpassing state-of-the-art membranes and Robeson’s upper bound for H2/CO2 separation. When challenged with a 3-day simulated syngas test containing water vapor and a 340-day stability test at 200 °C, the membrane shows stable separation performance. The robust H2/CO2 separation properties coupled with excellent scalability demonstrate the great potential of these organosilica membranes for economic H2 production with minimal carbon emissions.

Graphene oxide (GO) membranes have been extensively investigated for dye removal from wastewater, and they are often reduced or cross-linked to improve their stability, which, however, decreases water permeance. This study demonstrates an effective approach to enhance both durability and water permeance and retain dye rejection by synergistically integrating chemical etching using H2O2 and intercalation with polydopamine (PDA) to create hierarchical nanochannels. The nanopores on the holey GO (HGO) shorten the diffusion path, while the PDA intercalation increases the channel sizes and stabilizes the GO nanosheets. Optimized membranes exhibit water permeance of 70 - 120 LMH/bar (much higher than state-of-the-art commercial polyamide membranes) and a Congo Red rejection of 98.5%, better than GO membranes reported in the literature. Moreover, a membrane with water permeance of 70 LMH/bar exhibits stable performance in a 3-day continuous crossflow filtration test. The versatile approach reported here may be applied to other two-dimensional materials to create hierarchical nanochannels for desired separations.

Xun Wang,1,* Xiao Li,1,* Haifa Guo,1,* Lingxiang Zhu,2 Zhiyong Peng,3 Jun Wang,1 Fan Yang,1 Yong Guo4 1Department of Thoracic Surgery, Peking University People’s Hospital, Peking University, Beijing 100044, People’s Republic of China; 2National Research Institute for Health and Family Planning, Beijing 100081, People’s Republic of China; 3TargetingOne Corporation, Beijing 100190, People’s Republic of China; 4Department of Biomedical Engineering, School of Medicine, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Tsinghua University, Beijing 100084, People’s Republic of China*These authors contributed equally to this workCorrespondence: Fan YangDepartment of Thoracic Surgery, Peking University People’s Hospital, Peking University, Beijing 100044, People’s Republic of ChinaEmail yangfanpkuph@sina.comYong GuoDepartment of Biomedical Engineering, School of Medicine, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Tsinghua University, Beijing 100084, People’s Republic of ChinaEmail yongguo@tsinghua.edu.cnObjective: The aim of this study was to investigate the allelic relation between de novo T790M and concomitant sensitizing EGFR mutations in EGFR-TKIs naïve NSCLCs and to explore whether the formalin-fixed and paraffin-embedded (FFPE) materials affect the detection of de novo T790M mutation.Methods: Specimens of 300 consecutive EGFR-TKI naïve NSCLCs who received surgical resection between January 2016 and June 2018 were retrospectively investigated. All the snap-frozen tumor tissues from 300 NSCLCs were screened by droplet digital PCR (ddPCR) for the detection of de novo T790M mutation. The allelic relation between de novo T790M mutation and concomitant sensitizing EGFR mutations was also investigated. Furthermore, we assessed de novo T790M mutation in paired FFPE specimens of 50 patients which included tumor tissues and paired normal lung tissues of the pretreatment NSCLCs to investigate whether FFPE materials affect the detection of de novo T790M mutation.Results: The de novo T790M mutation was observed in four patients which included one patient of single de novo T790M mutation and three patients of de novo T790M mutation coexisting with L858R mutation. The incidence of de novo T790M in pretreatment NSCLCs who harboring EGFR mutations was 2.9% (4/139). All the de novo T790M mutations were detected in cis with the concomitant L858R mutations for the three NSCLCs. Our ddPCR method demonstrated that the frequency of de novo T790M mutation was ranging from 0.1% to 0.5% among 90% (45/50) of the FFPE tumor samples and 92% (46/50) of the paired FFPE adjacent normal lung samples. The frequency of de novo T790M mutation in the paired snap-frozen samples was all below 0.1%.Conclusion: Our study demonstrated that most de novo T790M mutations were detected in cis with concomitant sensitizing mutations for pretreatment NSCLCs. Analytical cut-off of ddPCR assay for FFPE specimens should be validated carefully considering the possibility of FFPE-derived artificial gene mutations.Keywords: non-small cell lung cancer, NSCLC, droplet digital PCR, de novo T790M, acquired T790M, EGFR mutation

An effective cross-linking technique allows a viscous and highly gas-permeable hydrophilic polyphosphazene to be cast as solid membrane films. By judicious blending with other polyphosphazenes to improve the mechanical properties, a membrane exhibiting the highest CO

Environmental mold (fungus) exposure poses a significant threat to public health by causing illnesses ranging from invasive fungal diseases in immune compromised individuals to allergic hypertensive diseases such as asthma and asthma exacerbation in otherwise healthy people. However, the molecular pathogenesis has not been completely understood, and treatment options are limited. Due to its thermo-tolerance to the normal human body temperature, Aspergillus. fumigatus (A.fumigatus) is one of the most important human pathogens to cause different lung fungal diseases including fungal asthma. Airway obstruction and hyperresponsiveness caused by mucus overproduction are the hallmarks of many A.fumigatus induced lung diseases. To understand the underlying molecular mechanism, we have utilized a well-established A.fumigatus extracts (AFE) model to elucidate downstream signal pathways that mediate A.fumigatus induced mucin production in airway epithelial cells. AFE was found to stimulate time- and dose-dependent increase of major airway mucin gene expression (MUC5AC and MUC5B) partly via the elevation of their promoter activities. We also demonstrated that EGFR was required but not sufficient for AFE-induced mucin expression, filling the paradoxical gap from a previous study using the same model. Furthermore, we showed that fungal proteases in AFE were responsible for mucin induction by activating a Ras/Raf1/ERK signaling pathway. Ca2+ signaling, but ROS, both of which were stimulated by fungal proteases, was an indispensable determinant for ERK activation and mucin induction. The discovery of this novel pathway likely contributes to our understanding of the pathogenesis of fungal sensitization in allergic diseases such as fungal asthma.

Amorphous polymers containing poly(ethylene oxide) are leading membrane materials for CO2 capture from fossil fuel-derived flue gas and syngas, such as those prepared from poly(ethylene glycol) diacrylate (PEGDA) and poly(ethylene glycol) methyl ether acrylate (PEGMEA). This work shows that introduction of zeolitic imidazolate framework-8 (ZIF-8) nanoparticles in these polymers increases CO2 permeability with minimal effect on CO2/H2 and CO2/N2 selectivity. Specifically, ZIF-8 nanoparticles with a size of 150–250 nm were synthesized and fabricated into mixed matrix materials (MMMs). The effect of ZIF-8 loading on gas transport properties at 35 °C in MMMs was systematically investigated. Adding 10 wt% ZIF-8 in the crosslinked PEGDA increases CO2 permeability from 130 Barrers to 320 Barrers unexpectedly by 170% without any reduction of CO2/light gas selectivity. While the CO2/light gas selectivity in the MMMs can be satisfactorily described using the Lewis-Nielsen model, the model underestimates the gas permeability. Despite a body of studies of MMMs comprising ZIFs, this work represents one of the few on the MMMs based on amorphous rubbery polymers elucidating the effect of ZIF-8 loading on the polymer properties and demonstrating their impact in achieving superior CO2/H2 and CO2/N2 separation properties.

Trigger factor (TF) is a key component of the prokaryotic chaperone network, which is involved in many basic cellular processes, such as protein folding, protein trafficking, and ribosome assembly. The major chaperone site of TF has a cradle-like structure in which protein substrate may fold without interference from other proteins. Here, we investigated in vivo and in vitro the roles of hydrophobic and charged patches on the edge and interior of cradle during TF-assisted protein folding. Our results showed that most of the surface of the cradle was involved in TF-assisted protein folding, which was larger than found in early studies. Although the inner surface of cradle was mostly hydrophobic, both hydrophobic and electrostatic patches were indispensable for TF to facilitate correct protein folding. However, hydrophobic patches were more important for the antiaggregation activity of TF. Furthermore, it was found that the patches on the surface of cradle were involved in TF-assisted protein folding in a spatial and temporal order. These results suggest that the folding-favorable interface between the cradle and substrate was dynamic during TF-assisted protein folding, which enabled TF to be involved in the folding of substrate in an aggressive manner rather than acting as a classic holdase.-Fan, D., Cao, S., Zhou, Q., Zhang, Y., Yue, L., Han, C., Yang, B., Wang, Y., Ma, Z., Zhu, L., Liu, C. Exploring the roles of substrate-binding surface of chaperone site in the chaperone activity of trigger factor.

Stimuli-responsive membranes have been widely explored to mitigate fouling on the membrane surface to achieve the stable performance of water purification. Herein, a facile one-step coating of photo-mobile materials on membrane surface was developed to impart self-cleaning property upon exposure alternatively to ultraviolet (UV) and visible light. Specifically, photo-mobile 4,4′-azodianiline (AZO) and a bio-adhesive polydopamine (PDA) were co-deposited on the surface of ultrafiltration (UF) membranes. The effect of the coating layer on the surface hydrophilicity and pure water permeance was systematically evaluated. The photoresponsive properties of AZO in solutions and thin films with PDA was characterized using UV–Vis absorption spectroscopy. When exposed with UV light, AZO undergoes photoisomerization from trans-AZO to cis-AZO, decreasing the volume, while the exposure to visible light enables the transition from the cis- to trans- configuration, increasing the volume. The resulted self-cleaning behavior of the modified membranes through the reversible volume change is demonstrated in treating 1 g/L bovine serum albumin (BSA) solution. After exposure to the alternative UV/vis light, the AZO-coated UF membranes showed an increased water permeance by ~160%.

Polymers with efficient and tight chain-packing and thus strong size-sieving ability are of great interest for H2/CO2 separation. Herein, we demonstrate a new approach to manipulating polymer structure by acid doping, leading to superior H2/CO2 separation performance. We have doped polybenzimidazole (PBI) with polyprotic acids, specifically H3PO4 and H2SO4. These acids cross-link PBI chains and drastically decrease free volume, improving the material's H2/CO2 selectivity to far surpass the Robeson's 2008 upper bound for membrane performance. For example, PBI doped with H3PO4 at a molar ratio of 1 : 1 exhibits an unprecedented H2/CO2 selectivity of 140 at 150 °C, which exceeds that of previously known polymeric materials and is superior or comparable to that of state-of-the-art 2D materials with sharp size separation, such as graphene oxide, MoS2, and metal–organic frameworks. This facile approach to enhancing polymer chain-packing efficiency opens up a new avenue for designing strong size-sieving polymers for membrane gas separations.

New polymeric blend membranes for CO2 separation were synthesized based on insights from molecular dynamics simulation. A molecular-level structure-property relationship in polymers of intrinsic microporosity (PIM) based blend membranes was investigated in detail computationally. Calculated local density profiles and energy of interaction of the blend membranes, composed of PIM-1 and various polyphosphazenes, showed that using the polyphosphazene with a higher concentration of ether side chains can improve the compatibility with PIM-1. Based on the findings of computational studies, blend membranes were experimentally fabricated from PIM-1 and polyphosphazenes with various polyether side chain concentrations. Polyether concentration in polyphosphazenes was correlated with the film properties and gas transport performance of the blend membranes. Blend membranes showed very high CO2 permeability (3100-5300barrer) and improved CO2/N2 selectivity (24–28), outperforming all other PIM-based blend membranes reported to date. Moreover, the CO2 permeability performance of the blend membranes was tested 566 h under real post-combustion flue gas from a coal-fired power plant, including CO2, N2, H2O, O2, SOx and NOx.

Gas permeation through ultrathin film composite (uTFC) membranes can be restricted by the pore size and porosity of the porous supports, resulting in a reduction in permeance. Although this geometric restriction has been demonstrated using empirical and computational models, a systematic experimental validation of the models is still lacking. This study addresses the gap by preparing a series of uTFC membranes comprising glassy perfluoropolymers (such as Teflon AF1600 and Hyflon AD80) as selective layers on top of a commercial poly(ether sulfone) (PES) microporous support and investigating the effects of the surface morphology and selective layer thickness on the gas permeance. The geometric restriction resulting from the porous support becomes more severe as the selective layer becomes thinner. For example, the PES support decreased the gas permeance of a 100-nm-thick Hyflon AD80 film by as much as 42%. The experimental data agreed well with the modeling results, which convincingly confirms that porous s...