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Porous membranes with under-liquid dual superlyophobic properties, which are difficult to achieve because of a thermodynamic contradiction, have attracted considerable interest in the field of switchable oil/water separation. Herein, a bioinspired mesh membrane with alternating hydrophilic and hydrophobic chemical patterns on its surface that endows it with superamphiphilic and under-liquid dual superlyophobic properties is fabricated by a simple liquidus modification process. The as-prepared membrane possesses a combination of under-oil superhydrophobic and under-water superoleophobic characteristics in the absence of external stimuli. Moreover, it can effectively perform the on-demand separation of various oil/water systems, including immiscible oil/water mixtures and oil/water emulsions owing to its under-liquid dual superlyophobic properties.

The preparation of self-supporting anion exchange membranes with enhanced mechanical strength and ultrathin thickness is still a challenge to improve the performance of fuel cells.

The side chains detach from the main chains of polymers, which leads to a transition of ion channels to micropores.

The development of a simple and efficient methanol-resistant membrane strategy is of great significance for improvement of the performance of fuel cells, making it an attractive and challenging topic. In this work, sulfonated covalent triazine framework (SCTF) nanosheets are prepared by a micro-interface method and post-sulfonation, which show excellent dispersion in polar solutions, such as water and N, N-Dimethylacetamide (DMAc). Then a series of composite proton exchange membranes (SCTF-x@SPP-co-PAEKs) are prepared by blending these SCTF nanosheets with sulfonated micro-block copolymers (SPP-co-PAEKs) resin. The results show that the appropriate addition of SCTF can significantly improve the proton conductivity (PC), methanol resistance and fuel cell performance of the prepared composite membrane, which can be attributed to the good interfacial compatibility between the SCTF nanosheets and the sulfonated micro-block copolymer matrix. The passive direct methanol fuel cells (DMFCs) with SCTF-x@SPP-3 membrane exhibit power density in the range of 28.0–33.3 mW cm−2 at 25 °C, which is superior to the related values of the pristine membrane and the commercial Nafion® series membranes.

Aqueous organic flow batteries have attracted dramatic attention for stationary energy storage due to their resource sustainability and low cost. However, the current reported systems can normally be operated stably under a nitrogen or argon atmosphere due to their poor stability. Herein a stable air-insensitive biphenol derivative cathode, 3,3′,5,5′-tetramethylaminemethylene-4,4′-biphenol (TABP), with high solubility (>1.5 mol L−1) and redox potential (0.91 V vs. SHE) is designed and synthesized by a scalable one-step method. Paring with silicotungstic acid (SWO), an SWO/TABP flow battery shows a stable performance of zero capacity decay over 900 cycles under the air atmosphere. Further, an SWO/TABP flow battery manifests a high rate performance with an energy efficiency of 85% at a current density of 60 mA cm−2 and a very high volumetric capacity of more than 47 Ah L−1. This work provides a new and practical option for next-generation practical large-scale energy storage.

The preparation of polyelectrolytes with excellent stability in high alkaline conditions still faces several challenges. In this study, we report a novel imidazolium-ionized monomer PhIM [PF₆], modified by the propylbenzene group on the position of N1/N3, which can be copolymerized with 1,1,1-trifluoroacetone under superacid-catalyzed conditions. The main-chain poly(arylene–imidazolium) polymers with a controllable degree of functionalization, high molecular weight, and good solubility are successfully prepared without further postfunctionalization. Two copolymers (block-like and random) can also be prepared by introducing biphenyl as a comonomer and adjusting the feed order. Due to their different microstructures, the two copolymers exhibit different ion conduction behaviors, water absorption capacities, and mechanical properties. The obtained polymer membranes exhibit high hydroxide conductivities and high chemical stability even after treatment in a 10 M NaOH solution at 80 °C. In summary, we highlight a simple, effective, and low-cost strategy to prepare highly alkaline stable poly(arylene–imidazolium) polymers.

The development of anhydrous high-temperature proton-exchange membranes (HT-PEMs) combining durable high proton conductivity and modest mechanical properties is a huge challenge to macromolecular design and engineering. HT-PEMs with microporous structures, constructed by the inefficient chain packing of contorted and rigid polymer backbones with imidazole, are reported for the first time. It is found that the widespread and interconnected microporosity of the polymers endows the HT-PEMs with an excellent phosphoric acid (PA) doping level (ADL) and a corresponding superhigh proton conductivity, as well as suitable mechanical properties and PA-retention ability. An outstanding proton conductivity of 330.3 mS cm−1 is obtained at 180 °C under an anhydrous atmosphere, which is superior to those of reported HT-PEMs with far higher ADLs (

A novel microporous anion exchange membrane containing a spirobiindane segment and cardo moiety is successfully synthesized through superacid-catalyzed Friedel–Crafts-type polymerization. The devel...

Polymers of intrinsic microporosity (PIMs) with superhigh permeability have been widely studied for higher selectivity in the various separation processes. However, the disorder and wide-distributi...

What texts did Buddhists of South Asia and beyond read? How did they read, interpret, and use these texts? This essay focuses primarily on the first of the two questions and examines in this connection instances of citation found in the early Mūlamadhyamakakārikā commentaries and in a related Tibetan work as evidence of the uses of Buddhist texts. The collected samples indicate two major shifts in Indian and Tibetan Buddhist textual practices. The first transition occurred in the sixth and seventh centuries when Indian commentaries on the Mūlamadhyamakakārikā began to cite scriptural passages with greater frequency, especially from the Mahāyāna sūtras. The example of Tsong kha pa’s Madhyamaka work represents a later trend in which Tibetan writers repeated sūtra passages previously cited in the Indian texts that were the main objects of their study and attention. What emerges here is the pivotal role played by the middle-period Indian Mādhyamikas. Writers such as Bhāviveka and Candrakīrti contributed very substantially to the collection of core scriptural citations that were deployed in the Madhyamaka texts. While some of the sūtra passages these Indian Madhyamaka authors used were circulated outside the circle of their own philosophical tradition, others appear to have been newly collected through their private reading experience.

The supporting layer of nanofiltration membranes is critical to the overall nanofiltration performance. However, conventional supports lack efficient surface porosity, which leads to the limited utilization rate of the polyamide (PA) layer. Herein a double-skin-layer nanofiltration membrane with porous organic polymer nanointerlayers prepared via a two-step interfacial polymerization technique is presented to investigate the effect of the interlayers' pore properties on the performance of the thin-film composite. Nanometer interlayers with different pore sizes are fabricated via interfacial azo-coupling polymerization. The pore properties of the nanointerlayer extremely influence the permeance, where a suitable pore size of 4.22 nm promotes pure water permeance of up to 32.2 L m-2 h-1 bar-1, which is ∼3.8-fold greater than the membrane without an interlayer. However, an interlayer with 0.54 nm pores limits the performance (4.7 L m-2 h-1 bar-1), which is even lower than the unmodified membrane (7.5 L m-2 h-1 bar-1), because of the narrow pores and confined transport mode. However, the confined diffusion rate of amino monomers from the support to interface leads to a thinner PA layer of ∼45 nm and results in high flux. This work provides a facial route for the fabrication of interlayers and facilitate the design of high-performance membrane materials with interlayers.

Using eddy-covariance turbulence measurements over a Tibetan glacier, we present a description of scalar turbulence characteristics in the stable boundary layer. Interesting behaviours are demonstrated in terms of temperature–humidity de-correlation and dissimilarity. That is, a lack of perfect correlation occurs between the two scalars (i.e., correlation coefficients

Sulfonated covalent organic nanosheets (SCONs) with a functional group (−SO3H) are effective at reducing ion channels length and facilitating proton diffusion, indicating the potential advantage of SCONs in application for proton exchange membranes (PEMs). In this study, Nafion-SCONs composite membranes were prepared by introducing SCONs into a Nafion membrane. The incorporation of SCONs not only improved proton conductivity, but also suppressed methanol permeability. This was due to the even distribution of ion channels, formed by strong electrostatic interaction between the well dispersed SCONs and Nafion polymer molecules. Notably, Nafion-SCONs-0.6 was the best choice of composite membranes. It exhibited enhanced performance, such as high conductivity and low methanol permeability. The direct methanol fuel cell (DMFC) with Nafion-SCONs-0.6 membrane also showed higher power density (118.2 mW cm−2), which was 44% higher than the cell comprised of Nafion membrane (81.9 mW cm−2) in 2 M methanol at 60 °C. These results enabled us to work on building composite membranes with enhanced properties, made from nanomaterials and polymer molecules.

The Tibetan Plateau and its surroundings contain the largest number of glaciers outside the polar regions. In the past 100 years, the glaciers on the Tibetan Plateau and its surrounding areas have been retreating slowly. Since the 1990s, however, the state of glaciers has undergone abnormal changes. Compared with the data derived from the First Chinese Glacier Inventory (CGI) (1960s−1980s), the glacier volume in China decreased by approximately 20% and the glacier area was reduced by approximately 17.7%, based on the data derived from the Second CGI. In particular, the glacier mass loss of the small glaciers was characterized by an area less than 1 km2 and was more intensive than that of lager glaciers. Abnormal changes in the glaciers on the Tibetan Plateau and the surrounding areas are mainly reflected by the spatial pattern. Through the systematic analysis of the data on glacier area, terminal position, and mass balance changes, it was found that the glacier changes in the region experienced obvious spatial heterogeneity from 1990 to 2010. The “Karakoram glacier anomaly” in the eastern Pamir, Karakoram, and western Kunlun regions has exhibited slight mass stability or even glacier advance. However, the glaciers on the southeastern Tibetan Plateau experienced the most intensive and accelerated shrinkage. On the evaluated timescale, the state of glaciers on the Tibetan Plateau and its surroundings has undergone abnormal changes regarding the loss rate of glacier volume. In the past 50 years, most of the glaciers have had a negative mass balance. Moreover, the mass loss process has intensified, especially since the 1990s. It is estimated that the loss rate of glacier volume from the Tibetan Plateau was as large as −15.6 ± 10.1 Gt/a between 2003 and 2009. In addition to the abnormal changes in spatial patterns and temporal changes, the glaciers exhibited an abnormal change within the glacial system. The most significant variability within the glacier system was the abnormal change in the structure of glacier ice. Another abnormal change within the glacier system was that the glaciers showed a sustained slowdown concomitant with ice thinning. Abnormal warming at high altitudes is an important driver of abnormal changes in glaciers on the Tibetan Plateau and its surroundings. Moreover, these contrasting glacier behaviors on the Tibetan Plateau and surroundings are related to atmospheric circulation processes, especially interactions between the westerlies and the Indian Summer Monsoon. In addition, changes in glaciers on the Tibetan Plateau and its surroundings are closely related to the enhancement of human activities. The South Asian region on the southern slope of the Himalayas acts as a main source of severe anthropogenic aerosol emissions, especially that of black carbon. The black carbon transported from South Asia to the glaciers reduces the glacier’s albedo and thus accelerates glacier melting. As global warming intensifies, the abnormal glacier status will likely lead to more hazards, such as ice collapse and glacial lake outburst floods. To reduce the potential glacial risks on the Tibetan Plateau and surroundings, it is necessary to further strengthen the abilities of glacier monitoring and disaster prevention.

Glacier surface ablation and associated energy characteristics are important to glacier survival, but little is known about these on glaciers in the West Kunlun Mountains (WKM), Tibetan Plateau, mainly due to their inaccessibility. Based on the glacio-meteorological conditions and mass balance observations on the Guliya ice cap (GIC) in the WKM during 2015/’16, a distributed energy and mass balance model was applied to study the spatiotemporal variations of energy and mass balance on the GIC, and the response of mass balance to climate change. Modeled results revealed that compared to the Chongce glacier in the WKM which was observed to undergo a positive mass balance in the 1980s, the GIC suffered a small mass loss with an annual value of −0.193 ± 0.042 m water equivalent, and the equilibrium-line altitude has risen by approximately 70 m to locate at 6000 ± 19 m. Besides, over the entire observation period, the incoming energy supplied by net shortwave radiation was almost balanced by the energy loss through net longwave radiation, and most energy available for surface ablation was consumed by latent heat flux through sublimation, which became a significant feature of the energy balance on the GIC. Sensitivity experiments by changing model input data with synthetic climate scenarios, which were sampled from meteorological measurements and accounted for coupled climate variable perturbations, revealed that the mass balance of the GIC was more sensitive to the changes in moisture-related variables than that in temperature, and positive mass balance would only be given from scenarios with significantly increased annual precipitation and decreased air temperature compared to those observed in 2015/’16.

Aśvaghoṣa follows his scriptural sources closely in his narration of the story of the Buddha’s last journey leading to his nirvāṇa. The Buddhacarita and the Pāli Mahāparinibbānasutta mirror each other in their accounts of most of the places that the Buddha visited and the many events that took place during that journey. What the Buddhacarita and the Pāli sutta have in common also suggests that Aśvaghoṣa’s sources are already highly literary, even though the Buddhist poet transforms the traditional materials through versification and literary embellishment. He also freshly designs occasional religious dialogs and philosophical meditation. Aśvaghoṣa’s literary accomplishments met with different responses outside South Asia. In China, the translation of the Buddhacarita was used as an authority and a source of information in erudite biographies of the Buddha, a Buddhist history, a Buddhist encyclopedia, and lexicographical works. In Tibet, where Indian literary classics were actively studied, interpreted, and used as literary models, the Buddhacarita has been surprisingly ignored after it was rendered by a lesser known Tibetan translator between 1260 and 1280.

The lotus leaf has the Janus wettability and outstanding floatability at multiphase interface. The ingenious design on lotus leaf surfaces enlightens us to fabricate the superhydrophobic/superhydrophilic binary cooperative membrane. Making use of the poor permeability of the candle soot, deposition of a layer of candle soot enables to form the Janus membrane with anisotropic wettability on different surfaces. After fixed by the hydrophobic polymer, the superhydrophobic/superhydrophilic binary cooperative membranes are prepared successfully on various membranes, such as filter paper, cotton fabric and copper mesh. The Janus membrane exhibits excellent interfacial floatability at the immiscible oil–water interface as a separator, thus affording high-performance immiscible oil/water separation without applied external pressure.

An innovative tactic to prepare porous organic polymer membranes was developed via interfacial azo-coupling polymerization. The membranes possess plentiful anchoring sites for loading Pd nanoparticles, and served as a membrane reactor, which exhibits high-performance catalytic reduction with a flux of 27.3 t m−2 day−1 and good long-term stability due to almost zero Pd leaching.

The stable isotopes (δ18O and δD) of water vapor are used to characterize continuous variations in large-scale and boundary-layer atmospheric processes. We presented continuous measurements of δ18O in surface water vapor at Lhasa, southern Tibetan Plateau, from October 2018 to September 2019 to investigate how large-scale and local atmospheric processes influence variations in water vapor δ18O at different time scales. The water vapor δ18O measurements reveal different seasonal characteristics and diurnal patterns. At the seasonal scale, δ18O exhibits a W-shape with two maxima in May–June and October as well as two minima in July–August and February. The diurnal variations in the water vapor δ18O and meteorological data throughout the year present distinct occurrences of maxima and minima during different periods. We found that the significant seasonal variability is mainly associated with the transition between the Indian summer monsoon and the westerlies, which transport distinct moisture to the southern Tibetan Plateau. The local temperature, specific humidity and boundary layer height impact the diurnal variations in water vapor δ18O to some extent with remarkable seasonal differences. publishedVersion

A novel liquid-infused, patterned, porous membrane system with anti-fouling characteristics is prepared via simple co-infusion of oil and water within hydrophobic and superhydrophilic surfaces of a porous membrane, respectively. This membrane simultaneously repels the immiscible water and oil exhibiting excellent interfacial floatability at the oil–water interface as a separator, thus showing promise for use in applications in the immiscible oil/water separation industry and liquid–liquid extraction.

A novel liquid-based Janus porous membrane system was developed through the simple infusion of water and oil within different surfaces. This generates a stable liquid-infusion interface that repels immiscible organic solvents and water, and itself floats at the oil/water interface as a separator. The developed membrane successfully acts as a simple alternative for high-performance liquid separation.

A series of guanidinium-based cations with various N-substituted groups (methyl, ethyl, isopropyl, cyclobutyl, benzyl and phenyl) were synthesized and their alkaline stabilities were evaluated by 1H NMR analysis. The results indicated that the contribution of the substituent group toward the stability followed the sequences: isopropyl > ethyl > benzyl > phenyl and ethyl > methyl > cyclobutyl. The relative stability sequences suggested that free and bulky alkyl substituent groups with large steric hindrance can dramatically improve the alkaline stability. Tetraethyl-benzyl-isopropyl guanidinium showed the highest alkaline stability which remained unchanged after treatment with 1 mol L−1 KOH/CD3OD at 60 °C for 312 h. Novel polysulfone anion exchange membranes (AEMs) with such stable guanidinium cations were prepared via iridium-catalyzed C–H activation and the Suzuki–Miyaura reaction. The obtained guanidinium functionalized AEM exhibited excellent resistance to alkaline solutions (after immersing in 1 mol L−1 NaOH at 60 °C for 30 days, no degradation was observed), indicating that AEMs functionalized by guanidiniums with large steric hindrance are very promising materials for AEM applications.

Fouling resistant zwitterionic analog ultrafiltration polymer membranes are fabricated from the composite mixture of virgin polysulfone (PSf), chloromethylated polysulfone (CMPSf), and oxidized nano-carbon black (ONCB) using phase inversion process. The chemical characterization of the membranes is performed by 1H NMR, FT-IR and Raman spectroscopy. Thermal gravimetric analysis and scanning electron microscopy are used to determine thermal behavior and morphology of membranes, respectively. Furthermore, surface contact angles, water uptake, and zeta potential of the membranes ensured the hydrophilicity, charges and surface properties of the membranes. The results confirmed the successful fabrication of porous, hydrophilic, and zwitterionic analog ultrafiltration composite membranes. The control and composite membranes are then thoroughly investigated for antifouling properties using BSA as standard foulant. The M4 membrane fabricated from a composite of PSf with CMPSf/ONCB exhibited the highest water flux of 320 L m−2 h−1 and 87% BSA rejection. The zwitterion analog membrane also exhibited the lowest irreversible fouling and highest flux recovery ratio among all tested membranes, thus considered as a potential candidate as antifouling membrane. Moreover, the present strategy also offered facile route for the preparation of membranes comprising zwitterion features and excellent antifouling properties.

Although Candrakīrti has been a focus in the recent scholarly attention on conventional reality (saṃvṛtisatya) in Buddhist philosophy, the complexity of his discussions of the status of phenomenal world on the surface or conventional level has not been adequately explored. In cataloging the wide-ranging interpretations that Candrakīrti has offered, this paper identifies several clusters of connected ideas that are delineated here as dimensions of Candrakīrti’s conventional reality. It will be shown that his thoughts on the subject have divergent orientations, ranging from commonsensical to technical. Thus, on the one hand, conventional reality represents the beliefs and consensus that ordinary people share about their world, while, on the other, traditional Madhyamaka, grammar, and Abhidharma discourses are used to provide linguistic and Buddhist doctrinal outlines of that same reality. The mobilization of available resources affords Candrakīrti several layers of articulation, as it does again for the eighth-century writers Jnānagarbha and Śāntarakṣita, who bring Dharmakīrti’s thought and Yogācāra philosophy to bear on the Madhyamaka theory of conventional reality.

Porous membranes, which consist of air-filled or liquid-filled pores, provide a gating strategy for tunable multiphase selectivity separation, and exhibit tremendous application potential in fields involving intelligent liquid management. Herein, we report the fabrication of a novel asymmetric wettability Janus porous membrane (JPM) based on bio-inspired models that integrate the air-gate floating mechanism and adhesive proteins secreted by mussels to attach to material-independent surfaces. The JPM fabricated through this novel and straightforward methodology has distinct hydrophobic-hydrophilic properties and interfacial compatibility. These features were engineered for F-oil (lubricant oil, Dupont Krytox 105) infused F-free JPM membrane filtration. The hydrophilic layer infused with high-surface-energy water acts as a perfect barrier (liquid gating) preventing invasion of the low-surface-energy F-oil which was infused in the hydrophobic surface, protecting the F-oil in the JPM. This is the first report regarding F-oil infused membrane filtration using the F-free-membrane, which can overcome the limitations of F-substrates for F-oil infused filtration.

It is well recognized by the scientific community that the fog can be deposited and transported on asymmetric surfaces, thus numerous efforts have been made to create such surfaces. However, it is still challenging to design a surface capable of fast deposition and rapid transportation simultaneously. Herein, inspired by the asymmetric structure of cactus spines and the cooperative hydrophilic/hydrophobic regions of desert beetles, a superhydrophilic-hydrophobic integrated conical stainless steel needle (SHCSN) is fabricated by a facile method. This integrated needle surface combines the merits of the fast deposition of fog on hydrophobic region and then rapid transportation on superhydrophilic surface. The droplet average transportation velocity on SHCSN is greater than other types of surfaces because of large Laplace pressure and self-driven phenomenon at its superhydrophilic-hydrophobic boundary. The best fog harvest efficiency was realized by optimizing the length of the hydrophobic region using theoretical modeling and experimental exploration, whereas the robust superhydrophilic needle surface induced the increase of collection time. This SHCSN was realized to be more efficient in fog collection than uniform superhydrophilic, uniform hydrophobic/superhydrophobic needle surfaces.

The Tibetan glaciers are greatly affected by the circulations of the westerlies and the Indian summer monsoon (ISM), but the mechanisms remain to be elucidated. In this project, we investigated the surface energy and mass balance of the Qiangtang No.1 Glacier in the inland Tibetan Plateau. Combining 4-year mass balance and meteorological records near the equilibrium line altitude with an energy-based mass balance model, we found that the meteorological conditions, which determined the glacier surface ablation and mass accumulation, are critically linked to changes in the intensity of the westerlies and the ISM. The 4-year mass balance comparisons demonstrated that the enhancement of the ISM in June and July, especially June, greatly increases the mass accumulation but inhibits the glacial ablation in the melt season, shifting the mass balance in a positive direction. Moreover, the occurrence of the westerlies enhancement interrupts the dominance of the ISM in the melt season. The intensified westerlies in the early melt season (June) could not only reduce the mass accumulation but also enhance the mass loss in the following months. In addition, the enhancement of the westerlies in the main melt season (July) could also greatly influence the local meteorological conditions, with lower temperatures and humidity but higher wind speeds. Such meteorological changes significantly reduce glacial ablation because more energy is consumed by sublimation and/or evaporation, rather than surface melting. These findings will enhance our understanding of the mechanisms underlying gl

Membrane fouling in membrane filtration technology is the major obstacle in maximizing its efficiency leading to short membrane lifetime and high operating cost. Here we reported that the use of oxidized nanocarbon black (ONC) in the preparation of composite ultrafiltration membrane, suppresses the fouling together with improved hydrophilicity and water permeate flux. Nanocarbon black (NC) was oxidized using ammonium persulfate, while morphology, nature and extent of oxidized groups were determined through scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and ion exchange capacity (IEC) measurement. The dispersion of the ONC was stable in organic solvent (NMP) and in DI water even after 6 months. Oxidized nanocarbon black was incorporated in polysulfone matrix to prepare nanocomposite membranes (CNC) through phase inversion method. The influence of ONC on surface morphology, surface chemical composition, hydrophilicity, mechanical strength, surface negative charge, porosity, ultrafiltration and antifouling characteristics were evaluated. The results showed that inclusion of 1.0 wt% ONC enhance water permeate flux from 188.5 to 307 L m−2 h−1, protein rejection up to 97.6%, highest flux recovery ratio of 89.4% after three cycle permeation and lowest irreversible fouling of 10.5%. Considering relatively low cost, excellent antifouling properties and mechanical strength of CNC membranes, make it potential candidate as antifouling membrane for water purification.

Glacial lake outburst floods (GLOFs) have recently become one of the primary natural hazards in the Himalayas. There is therefore an urgent need to assess GLOF hazards in the region. Cirenmaco, a moraine-dammed lake located in the upstream portion of Zhangzangbo valley, Central Himalayas, has received public attention after its damaging 1981 outburst flood. Here, by combining remote sensing methods, bathymetric survey and 2D hydraulic modeling, we assessed the hazard posed by Cirenmaco in its current status. Inter-annual variation of Cirenmaco lake area indicates a rapid lake expansion from 0.10 ± 0.08 km2 in 1988 to 0.39 ± 0.04 km2 in 2013. Bathymetric survey shows the maximum water depth of the lake in 2012 was 115 ± 2 m and the lake volume was calculated to be 1.8 × 107 m3. Field geomorphic analysis shows that Cirenmaco glacial lake is prone to GLOFs as mass movements and ice and snow avalanches can impact the lake and the melting of the dead ice in the moraine can lower the dam level. HEC-RAS 2D model was then used to simulate moraine dam failure of the Cirenmaco and assess GLOF impacts downstream. Reconstruction of Cirenmaco 1981 GLOF shows that HEC-RAS can produce reasonable flood extent and water depth, thus demonstrate its ability to effectively model complex GLOFs. GLOF modeling results presented can be used as a basis for the implementation of disaster prevention and mitigation measures. As a case study, this work shows how we can integrate different methods to GLOF hazard assessment.

Four guanidinuium-functionalized model compounds containing different substituent groups were prepared, and the substituent effects on the overall alkaline stability of the guanidinium cations were investigated. Based on the good alkaline stability of the model compounds, novel guanidinium-based anion exchange membranes (AEMs), GPP-co-PAEK x, with controlled microblock structures were subsequently designed and synthesized in good yield via a three step reaction that included a fluorophenyl-amine reaction, methylation and nickel (0)-catalyzed coupling. Notably, the use of a hydrophilic, guanidinium cation-containing component as a raw material in the direct synthesis of AEMs via nickel(0)-catalyzed coupling avoided using hygroscopic Vilsmeier salts and is obviously different from the conventional method that involves bromomethylation or post-quaternization. The GPP-co-PAEK x membranes exhibited lower water uptake values (≤23.4% at 60 °C) and hydroxide conductivities comparable to those of others reported randomly functionalized guanidinium-based AEMs with similar ion exchange capacity (IEC) values. This finding indicates that the GPP-co-PAEK x membranes with controlled microblock structures possess well-developed hydrophilic/hydrophobic nanophase separation, which was confirmed by transmission electron microscopy (TEM). Moreover, long-term alkaline stability tests demonstrated that the alkaline stability of both the hydrophilic guanidiniums groups and the copolymer backbone contributed to the good alkaline stabilities of the GPP-co-PAEK x membranes.

Fundamental problems in thin film composite (TFC) reverse osmosis (RO) membranes in terms of the interfacial adhesion between the support and the active layer, the impact of support surface pore characteristics on the active layer formation process and the accordingly obtained active layer properties were investigated. Paper studies mainly includes following aspects: Five types of polysulfone (PSf) supports with varied surface pore characteristic properties were prepared and characterized; Thin film composite (TFC) polyamide (PA) reverse osmosis (RO) membranes were fabricated on these supports via in situ interfacial polymerization (IP) technology under identical IP protocols, and the performance and properties of the obtained TFC membranes were investigated systematically; Three types of these supports produced TFC membranes with both good salt rejection and high water flux. On the other hand, two types of them produced TFC membranes with inferior salt rejection attributed to the delaminated active layer from the support; The root cause for the delamination was explored and a speculated mechanism model for it and for the impact of support surface pore characteristic on the active layer formation was proposed. Furthermore, profilometer was used for the first time to measure the accurate thickness of individual active layer to overcome the shortcomings of the conventional electron microscope technologies. The basic understanding of the interplay between the support and the active layer provides important information for developing of thin film composite (TFC) membranes with improved performance.

To design and construct high ionic conductive anion exchange membranes (AEMs), tetra-pyrrolidinium-based block poly(arylene ether sulfone)s were synthesized. Pyrrolidinium groups were densely and controllably introduced into the polymer scaffold using a novel tetra-functionalized monomer, 4, 4′-oxybis (2,6-bis(pyrrolidinyl-1-methyl) phenol) (OBBPYP), which was synthesized via the Mannich reaction. To obtain chemically stable pyrrolidinium cations, the alkaline stabilities of pyrrolidinium-based cationic model compounds with various N-substituted alkyl chains (methyl, ethyl, butyl) were studied using 1H nuclear magnetic resonance (1H NMR) spectroscopy, in which methyl as the N-substituent group exhibited the highest alkaline stability. Based on the results above, a targeted, well-controlled, multiblock structure AEM (QQBPES-2.4OH) with densely concentrated pyrrolidinium cations was obtained via an iodomethane quaternization reaction. The densely concentrated ionic groups provide ionic nanochannels for hydroxide conduction, and the hydrophobic polymer backbone is responsible for the critical membrane mechanical support. As confirmed by transmission electron microscopy (TEM) and small angle X-ray scattering (SAXS), the QQBPES-2.4OH membrane exhibited a more obvious hydrophilic-hydrophobic microphase structure, compared to the random di-pyrrolidinium cation-based AEM (DQRPES-2.4OH) and tetra-pyrrolidinium cation-based AEM (QQRPES-2.4OH). Moreover, the QQBPES-2.4OH membrane exhibited considerably higher hydroxide conductivity, up to 68.0 mS cm−1 at 80 °C, better flexibility and lower water swelling. The results of this work suggest a novel and scalable approach to the functionalization of polymers for AEMs.

Ultrafiltration membranes with integrated antimicrobial and antifouling properties were fabricated using an engineering thermoplastic (carboxylated cardopoly(aryl ether ketone, PEK-COOH). Different molecular weights of PEO (Mw: 120, 350, 550) were grafted to the PEK-COOH membrane surface via EDC/NHS methodology. N-chloramine modified membranes then were prepared by simple exposure to dilute sodium hypochlorite solution. The surface grafting processes were all performed in water (i.e. without organic solvent). With this surface modification, the hydrophilicity of membranes improved significantly and the pure water flux increased compared to the unmodified PEK-COOH membrane. Furthermore, the PEO and N-chloramine modified membranes were resistant not only to both protein adsorption and bacterial adhesion, but also to microbial proliferation. The results of this work suggest that PEO and N-chloramine modified membranes are promising as fouling-resistant membranes.