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In the absence of a national Palestinian state and in response to the oppressive daily practices of the British Mandate government, the Israeli settlers’ colonial occupation and the Arab governments that ruled the West Bank and Gaza between 1950 and 1967, the Palestinian community has had to create and develop a set of indigenous resilience strategies. Muslih (1993) and Faraj (2017) refer to all these strategies as ‘A’mal Ejtima’y’, or ‘popular social work’, characterised by collectivism, public participation and non-hierarchical design, which has played a role in mobilising masses and facilitating youth engagement in the decolonisation process. Despite more than a century of existence of this form of social work in Palestine, it has received marginal or no attention from formal social work education and research. Recent years have witnessed some indications of the ‘resurrection’ of community social work in its very popular version.

A smart diffraction grating immunosensor based on antigen-responsive hydrogel with enhanced analyte-induced volume changes is developed for highly selective and sensitive detection of human immunog...

By combining near infrared spectroscopy and differential pressure meter to measure flow rate and phase volume fraction, a new structure of the near infrared system located in the position of the Venturi tube of long throat was proposed. The flow rate and volume fraction of the bubble flow were measured in a vertical experimental line. In terms of volumetric content measurement, based on typical flow characteristics, a void age model was established and experimentally verified. In terms of flow measurement, the classical measurement model is compared, and the uniform flow model is selected as the flow measurement model and corrected. The results show that the measurement error under the bubbly flow condition of the liquid volume fraction and the gas volume fraction was within ±0.52% and ±10%, respectively. The relative error of total flow measurement was within ±1.01%.

The exploration of functional nanomaterials with superior catalytic activity for practical photocatalytic water decontamination is of significant importance. Perovskite-based nanomaterials, which demonstrate excellent photophysical and catalytic properties, are widely investigated as a class of adaptable materials for the photocatalytic degradation of environmental pollutants. This chapter introduces the recent progresses in using perovskite-based nanocomposites with particular emphasis on the applications for effective photocatalytic degradation of organic pollutants in wastewater. It starts by presenting the general principles and mechanisms governing photocatalytic degradation of organic pollutants in water by perovskite, along with the design criteria for perovskite-based nanocomposites. It then explains various strategies used to prepare perovskite-based nanocomposites with the aim of enhancing their photocatalytic activity. By the end of the chapter, the remaining challenges and perspectives for developing efficient perovskite-based photocatalysts with potential large-scale application are highlighted.

Pigmentary coloration can produce viewing angle-independent uniform colors via light absorption by chromophores. However, due to the limited diversity in the changes of the molecular configuration of chromophores to undergo color change, the existing materials cannot produce a wide range of visible colors with tunable color saturation and transmittance. Herein, we propose a novel strategy to create materials with a wide visible color range and highly tunable color saturation and transmittance. We fabricated a hydrogel with poly (acrylamide-co-dopamine acrylamide) networks swollen with Fe3+-containing glycerol/water in which the covalently crosslinked polyacrylamide backbone with pendant catechols can ensure that the hydrogel maintains a very stable shape. Hydrogels containing adjustable catechol-Fe3+ coordination bonds with flexible light-interacting configuration changes can display a wide range of visible colors based on the complementary color principle. The catechol-Fe3+ complexes can dynamically switch between noncoordinated and mono-, bis- and tris-coordinated states to harvest light energy from a specific wavelength across the whole visible spectrum. Therefore, these hydrogels can be yellow, green, blue, and red, covering the three primary colors. Moreover, color saturation and transmittance can be flexibly manipulated by simply adjusting the Fe3+ content in the hydrogel networks. The versatility of these smart hydrogels has been demonstrated through diverse applications, including optical filters for color regulation and colorimetric sensors for detecting UV light and chemical vapors. This proposed smart hydrogel provides a universal color-switchable platform for the development of multifunctional optical systems such as optical filters, sensors, and detectors.

The hierarchical design of mesoscale structures in droplet templates determines the structure and functionality of the resultant microparticles. In this review, we summarize recent progress on the control of microfluidic emulsion templates for the synthesis of polymeric microparticles with desired functionality and internal structure. We introduce strategies for controlling the morphology and interfacial stability of emulsion templates. These strategies are based on manipulation of the mesoscale structure of amphiphilic molecules and nanoparticles at emulsion-droplet interfaces. We also discuss strategies for controlling the mesoscale structure of microparticles, which involve manipulating the interfacial mass-transfer and chemical reactions during template synthesis. We provide insight on the use of these strategies for the rational design and fabrication of polymeric microparticles with predictable internal structures and functionality at the single-particle level.

A simple grating system based on poly(N-isopropylacrylamide-co-acrylamide) (poly(NIPAM-co-AAm)) hydrogel for sensitive and rapid detection of ethanol concentration is developed. The hydrogel gratin...

The preparation of microparticles with non-spherical shapes has attracted increasing interest because the special physical properties of non-spherical microparticles can increase their performance in a wide variety of industrial applications and clinical pathologies. Here a simple and flexible approach is developed to fabricate monodisperse bullet-shaped microparticles with controlled structures from microfluidic droplet templates, which are deformed by both shear stress from outer fluid and spatial confinement from microchannel. The deformation of droplet templates can be simply controlled by varying the flow rate of outer fluid and the inner diameter of collection tube. By multiplying the microfluidic device, bullet-shaped microcapsules with different internal structures can be easily fabricated from deformed double emulsion droplets. The results of flow characteristics show that, the bullet-shaped microparticles have a higher velocity than the spherical microparticles with the same volume if they flow in the microchannel with smaller diameter than the length of the bullet-shaped microparticles; whereas their flowing velocity is slightly lower than that of spherical microparticles in the microchannel if the channel diameter is larger than the length of bullet-shaped microparticles. In microchannels of a model device, bullet-shaped microparticles show better embolization performance than spherical ones. The bullet-shaped microparticles and microcapsules are promising as materials candidates in the fields of embolization therapy, substance transfer and drug release systems. The proposed strategy in this study provides a facile route for fabricating bullet-shaped microparticles with controlled structures and presents intriguing possibilities for growing researches including non-spherical microparticles and micromachine systems.

A novel smart membrane with ion-recognizable nanogels as gates on interconnected pores is developed for simple and rapid detection of trace lead(II) ions in water. The membrane is prepared via one-step vapor-induced phase separation (VIPS) method, and featured with interconnected porous structure and Pb2+-responsive poly(N-isopropylacrylamide-co-benzo-18-crown-6-acrylamide) (PNB) nanogels on polyethersulfone (PES) membrane pore surfaces as gates. Afforded by such a unique architecture, both high flux and significant responsive characteristics are achieved. With the proposed strategy, the nanogels are fixed onto the membrane pore surfaces during the formation of interconnected porous structure; thus, the immobilization of nanogels onto the membrane pore surfaces does not result in the decrease of pore sizes. The water fluxes of fabricated membranes could be even higher than 6000 kg m−2 h−1 driven by the static pressure of 20 cm water column under gravity at 34 °C, because of the three-dimensionally interconnected porous structures. Due to high sensitivity and selectivity of PNB nanogels on the membrane pore surfaces in response to Pb2+ ions, the fabricated membranes can efficiently detect Pb2+ ions with a limit of detection as low as 10−9 mol/L. With the proposed novel membrane, rapid detection of trace lead(II) ions in water can be easily achieved by simply monitoring the trans-membrane flux change in a gravity-driven membrane module device, which is highly potential and promising in real-time and easy-to-popularize monitoring of drinking water safety and may expand the scope of applications of facile detection techniques.

The noise signals of gas-liquid two-phase flow contain abundant information, which can reflect the change of gas liquid two phase flow rate, phase holdup and flow rate and so on. In this paper, acoustic emission technology is used to quantitatively measure the noise of gas-liquid two-phase flow, and the flow noise signal is analyzed by using chaotic information processing technology. The delay time was determined though compared the four methods, the average displacement method, autocorrelation method, mutual information method and C-C algorithm, finally, C-C algorithm was selected. Compared with four kinds of embedding dimension methods: the FNN method, Cao's algorithm, G-P algorithm, and C-C algorithm, The G-P algorithm is adopted to calculate the embedding dimension of phase space reconstruction. The attractor is reconstructed using polar coordinate space. At the same time, five parameters of correlation dimension, K-entropy, Hurst exponent, mobility and complexity are applied to quantitatively analyze chaotic attractors. The analysis shows that the polar coordinates clearly indicate the amplitude and phase signals of the gas and liquid phases acquired by the acoustic emission system in the gas-liquid two-phase flow; From the five characteristic parameters, it can be seen that when the flow pattern changes, the mobility increases instantly by 76.92%. With the increase of the gas volume, the mobility growth rate increases from 12.43% to 62.01% under the same flow pattern. The complexity has decreased by 33.65%. When there is a large amount of traffic, it will reduce the correlation dimension to 96.61%, and the K-entropy will decrease to 97.53%. The chaotic characteristics describe the variation of gas-liquid two-phase flow, which provides another idea for the flow-type transformation.

In order to better understand the mechanisms of two-phase flow and the prevailing flow regimes in horizontal pipelines, the evaluation of interphase forces is paramount. This study develops a method to quantitatively estimate the interphase force in two-phase gas-water flow in horizontal pipeline. The electrical resistance tomography technology is used to measure the void fraction, while the differential pressure perpendicular to the horizontal pipe is measured in different flow patterns via a Differential Pressure sensor. The inner pipe diameter is 50 mm, the water flow range from 3.26 m3/h to 7.36 m3/h, the gas flow rate range from 1 to 60 l/min, which covered a range of flow patterns, the absolute pressure range from 0.07 MPa to 0.12 MPa. The relationship between the differential pressure drop and interphase force is established, and the effects of these forces on the flow are analyzed. Experimental results indicate that the dual-modality measurement system was successfully provided a quantitative evaluation of interphase forces in two-phase horizontal gas-water flow.

A novel composite catalytic membrane is developed by blending silicon oxide coated ferroferric oxide (Fe3O4@SiO2) nanoparticles in polyether sulfone (PES) membrane as Fenton-like catalysts via liquid-induced phase separation (LIPS) method. By introducing Fe3O4@SiO2 nanoparticles in PES membrane matrix, the surface hydrophilicity, porosity and mean pore diameter of as-prepared composite catalytic membranes are improved due to the hydrophilic nature of the SiO2 coating layer on the Fe3O4@SiO2 nanoparticles. The as-fabricated catalytic membrane can filter large particles above ~100 nm and shows a high water flux of 2084 kg m−2 h−1 under 0.1 MPa. Importantly, the composite catalytic membrane shows efficient catalytic performance and satisfactory stability in the degradation of organic pollutants based on the Fenton-like reaction mechanism. The proposed strategy for membrane fabrication and the experimental results in this study provide valuable guidance for developing high-flux catalytic membranes with efficient catalytic performances for treatment of industrial and municipal wastewater.

This paper proposes a novel method to measure each constituent of an oil–gas–water mixture in a water continuous flow, typically encountered in many processes. It deploys a dual-plane electrical resistance tomography sensor for measuring dispersed phase volume fraction and velocity; a gradiomanometer flow density meter and a drift flux model to estimate slip velocities; with absolute pressure and temperature measurements. These data are fused to estimate constituent volume flow rates. Other commonly used operational parameters can be further derived: water cut or water liquid ratio (WLR) and gas volume fraction (GVF). Trials are described for flow rates of water 5–10 m3 h−1; oil 2–10 m3 h−1 and gas 1–15 m3 h−1. The comparative results are included with published data from the Schlumberger Gould Research flow facility. The paper proposes the use of the described configuration for measurement of volume flow rates in oil–gas–water flows with an absolute error of ±10% within GVF 9%–85% and WLR > 45%.

Bubble-propelled micromotors with well-engineered hierarchical porous structures are developed by a simple and flexible strategy for efficient water decontamination. Controllably and spontaneously evolved double emulsions from microfluidics are used as templates for continuous fabrication of the micromotors in one-step. The micromotors possess interconnected hierarchical porous structures with two well-aligned microscale pores incorporated in nanoporous matrix. The opening hole of one microscale pore at the bottom of micromotor is decorated with Fe3O4@Ag nanoparticles to decompose H2O2 for bubble-propelled motion. Due to their hydrophobic and magnetic hierarchical porous matrix, the micromotors can be used for capture of oil pollutants in water, and then easy recovery by using a magnetic field. Moreover, the micromotors can be flexibly functionalized by simply incorporating functional nanoparticles into the hierarchical porous structures for efficient water decontamination. This is demonstrated by modifyi...

Transparent thermo-responsive poly(N-isopropylacrylamide)-l-poly(ethylene glycol)acrylamide (PNIPAM-l-PEG) conetwork hydrogels with rapid deswelling response are prepared by using multi-arm star poly(ethylene glycol)acrylamide (multi-arm star PEGAAm) molecules as cross-linkers. The introduction of multi-arm star PEGAAm cross-linkers can restrain the formation of dense skin layers on the surface of PNIPAM-l-PEG hydrogels, and act like water channels to facilitate the release of water from the hydrogels, resulting in rapid deswelling response. Meanwhile, the internal conetwork structures of the PNIPAM-l-PEG hydrogels are much more homogeneous due to the regular chemical structures of the multi-arm star PEGAAm cross-linkers. The cross-linkers can directly cross-link PNIPAM chains and serve as the backbones of the conetworks. This reduces the strong aggregation of hydrophobic PNIPAM chains against the formation of heterogeneous microstructures within the hydrogels during the deswelling process, leading to the maintenance of their transparency even at a temperature higher than their gel collapse temperature (GCT). The transparent PNIPAM-l-PEG hydrogels with rapid deswelling response show great potential for engineering advanced sensors and devices for optical applications.

The preparation of phase change fibers with controllable morphology, structure and enhanced thermal conductive property is of particular importance to many applications and still remains a challenge. In this study, core–sheath composite phase change microfibers with enhanced thermal conductive property are successfully prepared by microfluidic strategy, which consist of Rubitherm®27 (RT27) core and poly(vinyl butyral) (PVB) sheath blended with aluminum oxide nanoparticles (Al2O3 NPs). The effects of Al2O3 NPs on the morphologies, mechanical properties, phase change properties and thermal conductive properties of the produced composite microfibers are systematically investigated. The morphologies of the composite microfibers are continuous cylindrical shape with core–sheath structure. The modified Al2O3 NPs are uniformly dispersed in PVB matrix, and the thermal conductive property of the composite microfibers has improved significantly. The surface temperature of the Al2O3-incorporated composite microfibers changes faster than that of microfibers without Al2O3. The melting and crystallization times of the composite microfibers with 12% Al2O3 are decreased by 47.1 and 39.5%, respectively. It is expected that the results can provide a valuable guidance for fabrication of phase change microfibers with satisfactory heat conductive properties as well as fast thermal regulation properties.

Graphene oxide (GO) membranes with diverse lamellar distances can achieve sieving of molecules of different sizes in aqueous solutions. Without the extra assistance of cross-linking, the increase of lamellar distance supported by self-contained oxidized groups could diminish the internal π–π attraction force of GO membranes, resulting in the instability of GO membranes. However, the critical value of oxidized-group-supported lamellar distance of unstable GO membranes in aqueous solutions, which is crucial in applications for precise sieving of molecules, still remains unknown. In this study, the effect of oxidized-group-supported lamellar distance on the stability of graphene-based membranes in aqueous solutions is systematically investigated. By controlling the content of oxidized groups via changing reducing condition, different lamellar distances of graphene-based membranes are obtained. With changing the lamellar distance in aqueous solutions under different pH conditions, the graphene-based membranes...

A simple device, which is equipped with a non-woven fabric filter medium immobilized with ion-recognizable smart hollow microgels, is developed for facile detection of trace lead(II) ions (Pb2+ ). The ion-recognizable smart microgels are made of poly(N-isopropylacrylamide-co-benzo-18-crown-6-acrylamide) (PNB), in which the 18-crown-6 groups act as the sensors of Pb2+ and the N-isopropylacrylamide groups act as the actuators. The PNB hollow microgels can isothermally change from a shrunk state to a swollen state in response to recognizing Pb2+ in the aqueous environment due to the electrostatic repulsion among the charged 18-crown-6/Pb2+ complex groups and the enhancement of hydrophilicity of the microgels. Due to the hollow structures, the PNB microgels show remarkable isothermal swelling ratio. Thus, the flux of solution pass through the non-woven fabric filter medium decreases significantly because of the remarkable reduction in the space for liquid flowing upon recognizing Pb2+ . The Pb2+ concentration can be detected quantitatively by simply and easily measuring the change of solution flux using the proposed device, which is operated without external power supply or spectroscopic measurements. The strategy proposed in this study provides a promising method for facile detection of trace Pb2+ in aqueous environments.

The preparation of poly(vinylidene fluoride) (PVDF) membranes with high mechanical strength via vapor-induced phase separation (VIPS) is still a great challenge. In this study, high strength PVDF membranes with cellular pore structure are successfully prepared by comprehensively regulating the process parameters such as the dissolution temperature (Td), vapor temperature (Tv) and exposure time (t) during the VIPS process, as well as the membrane-forming parameter i.e. mass fraction of PVDF polymer. The effects of these parameters on microstructure and performances of the PVDF membranes are systematically investigated. In the investigated ranges of t from 0.67min to 20 min, the membranes with cellular structure are obtained at both elevated Td and Tv of 65 °C, relative humidity of 70%RH and mass fraction of 15 wt% PVDF. All the PVDF membranes with cellular structure prepared at elevated Td and Tv of 65 °C exhibit high mechanical properties, and the tensile stress at break (σ*) and tensile strain are higher than 2.5 MPa and 15%, respectively. The PVDF membrane prepared at t of 0.5 min has a critical structure and shows the maximum σ* of 4.0 MPa and tensile strain of 33%, respectively. It is expected that the results provide a valuable guidance for the design and fabrication of membranes from semi-crystalline polymer with desirable performances.

Ion sieving is of great importance in a variety of applications, such as water desalination/purification, biomedical engineering and so on. The currently available techniques, based on ion size sieving by constructing membranes with nanochannels and nanopores, are still not able to achieve precise sieving of mono-/multi-valent metal ions. Here, we report on the fabrication of graphene-based membranes by constructing uniform two-dimensional (2D) nanochannels with effective channel heights of ~ 8 A for precise and efficient sieving of mono-/multi-valent metal ions. Our membranes with uniform 2D nanochannels are built using facilely reduced graphene oxide (FRGO) nanosheets, which are controllably fabricated by avoiding the corrugation of graphene oxide (GO) nanosheets and controlling the content of oxidation groups during the reduction process. We illustrate the ability of precise sieving of mono-/multi-valent metal ions afforded by this technique by fabricating FRGO membranes with uniform 2D nanochannels, and demonstrate the excellent repeatability and long-term stability of FRGO membranes for sieving of mono-/multi-valent metal ions.

A new type of inside and outside tubes differential pressure flowmeter was designed. The throat structure and single-end pressure tapping method is proposed. Three-dimensional numerical simulation is used for structural optimization. The experimental prototype is processed and calibrated in real-time. It was found that the differential pressure values of the new flowmeter was 3.4 times higher and pressure loss ratio only 20% of the original flowmeter in forward flow, while 2.6 times higher and pressure loss ratio only 25% in reverse flow. The sensitivity and energy efficiency of the novel flowmeter is shown to be significantly improved.

Population growth and global industrialization cause a dramatic increase in the amount of sewage sludge produced annually worldwide from Municipal and Industrial Wastewater treatment. The efficient measurement of sewage, which is a typical solid-liquid two-phase flow, has become an important issue that requires to be urgently addressed. In this study, an improved Ultrasonic Doppler Velocimetry (UDV) is proposed to optimize the probe design and hardware design, which reduces the influence of working frequency and echo reverberation on accuracy and improves the stability of the system. A Doppler peak extraction and superposition method is also put forward to correct the offset of Doppler peak frequency. In this paper, Particle Image Velocimetry (PIV) is used to calibrate the UDV system to modify the measurement model of ultrasonic Doppler liquid-solid two-phase flow, and dynamic experiments are carried out in a vertical steel pipe with inner diameter of 50 mm at different flow conditions. The results show that the accuracy and stability of UDV measurement system are greatly improved, with a maximum relative error of 1.49%.

A method that can rapidly and effectively capture and separate pathogenic bacteria, which remain viable even after capture for subsequent analysis, is potential future tool for medicine, water and food safety. In this study, novel antimicrobial peptide-based magnetic nanoparticles with neutralized bactericidal effects are developed for rapid and efficient capture and removal of pathogenic bacteria in water samples. The antimicrobial peptide-functionalized magnetic nanoparticles (AMP-MNPs) consist of magnetic core (Fe3O4), polydopamine (PDA) as an intermediate layer and antimicrobial peptide (Magainin I) as an outer layer (PDA@Fe3O4-AMP). The unique structure of AMP-MNPs allows retaining their capture ability via strong electrostatic interactions, while eliminating their bactericidal actions during interactions with bacteria’s outer membrane. The results of fluorescent microscopy indicate that the AMP-MNPs has no bactericidal effect, but only the binding ability towards bacteria. Factors such as concentration of AMP-MNPs, pH of the medium and ionic strength are crucial in mediating rapid and efficient bacterial capture. Higher concentration of AMP-MNPs (0.5 mg/mL) results in a high sensitive capture effect on 5 × 106–5 × 101 cfu/mL E. coli O157:H7, and a broad spectrum of capture ability towards various bacterial strains (1.5 × 107 cfu/mL) and allow rapid and efficient capture and magnetic-separation of pathogenic bacteria from tap and recreational water samples with capture efficiency greater than 97% and incubation time as short as 5 s. Whereas semi-selective capture of pathogenic and Gram-negative bacteria is achieved at lower concentration of AMP-MNPs (0.1 mg/mL). The developed AMP-MNPs may find great potential in microbiological applications and water quality analyses.

A novel method based on capsule membranes encapsulated with smart nanogels is successfully developed for facilely detecting trace lead(II) (Pb2+) ions, which are hazardous to both human health and the environment because of their toxicity. The capsule membrane system is composed of a semi-permeable calcium alginate membrane and encapsulated poly(N-isopropylacrylamide-co-acryloylamidobenzo-18-crown-6) (PNB) nanogels. The semi-permeable membrane allows Pb2+ ions and water to pass through quickly, but rejects the encapsulated nanogels and polymers totally. As soon as Pb2+ ions appear in the aqueous environment and enter into the capsule, they can be specifically recognized by encapsulated PNB nanogels via forming 18-crown-6/Pb2+ complexes that cause a Pb2+-induced phase transition of PNB nanogels from hydrophobic to hydrophilic state. As a result, the osmotic pressure inside the capsule membrane increases remarkably, and thus the elastic capsule membrane isothermally swells upon the presence of Pb2+ ions in the environmental aqueous solution. The Pb2+-induced swelling degree of the capsule membrane is dependent on the concentration of Pb2+ ions ([Pb2+]) in water. Thus, the [Pb2+] value in water is able to be easily detected by directly measuring the Pb2+-induced isothermal swelling ratio of the capsule membrane, which we demonstrate by using 15 prepared capsule membranes arranged in a line. The Pb2+-induced swelling ratios of the capsule membrane groups are easily observed with the naked eye, and the detection limit of the [Pb2+] in water is 10-9 mol L-1. Such a proposed method provides an easy and efficient strategy for facile detection of trace threat analytes in water.

A facile and efficient electrochemical biosensing platform based on screen printed carbon electrode (SPCE) modified with three-dimensional (3D) nanocomposite consists of reduced graphene oxide (RGO) with the insertion of silver nanowires (AgNWs) followed by the anchoring of silver nanoparticles (AgNPs) is constructed as RGO/AgNWs/AgNPs/SPCE for the simultaneous determination of dopamine (DA), uric acid (UA) and estriol (EST). The morphology characteristic and surface elemental composition of RGO/AgNWs/AgNPs nanocomposite are investigated by field-emission scanning electron microscope, transmission electron microscope and X-ray photoelectron spectroscope. Cyclic voltammetry, electrochemical impedance spectroscopy, linear sweep voltammetry and differential pulse voltammetry are utilized to explore the electrochemical performances of the constructed electrodes. Due to abundant active sites and excellent electrocatalytic activity of the nanocomposite, the RGO/AgNWs/AgNPs/SPCE sensor exhibits well-resolved oxidation peaks and enhanced oxidation peak currents in the ternary mixture of DA, UA and EST with respective linear response ranges of 0.6 to 50 μM, 1 to 100 μM and 1 to 90 μM and detection limits (S/N = 3) of 0.16 μM, 0.58 μM and 0.58 μM, respectively. Moreover, the constructed biosensor exhibits good selectivity, reproducibility and stability, and excellent performance in determining DA, UA and EST in synthetic urine samples with excellent recovery. The results reveal that the RGO/AgNWs/AgNPs nanocomposite is a promising candidate for advanced electrode material in electrochemical sensing field and possesses great application prospects in further sensing researches.

Novel composite membranes are successfully developed for simultaneous adsorption of heavy metal ions and catalytic degradation of organic contaminants by blending polydopamine-coated ferroferric oxide (Fe3O4@PDA) nanoparticles in polyethersulfone (PES) matrix via liquid-induced phase separation (LIPS) method. The permeabilities of the as-fabricated composite membranes are significantly improved by introducing Fe3O4@PDA nanoparticles, because the hydrophilic coating on the surface of Fe3O4@PDA nanoparticles enables to generate more microporous structures between the PES matrix and nanoparticles during the LIPS process. The composite membrane containing 20 wt% Fe3O4@PDA nanoparticles shows water flux as high as 2640 L∙m−2∙h−1∙bar−1, which is six times larger than that of PES blank membrane. The composite membranes exhibit efficient and repeatable performances for simultaneous adsorptive removal of heavy metal ions and catalytic degradation of organic contaminants based on the mechanism of Fenton-like reaction. The proposed composite membranes with multifunction of simultaneous catalytic degradation of organic contaminants and adsorption of heavy metal ions provide a new pathway to deal with some hard-to-be-treated wastewaters from papermaking, leather, textile printing-dyeing industries, and so on. Furthermore, the proposed one-step strategy for fabricating composite membranes with both large permeability and high separation efficiency in this work is easy to be scaled up.

Flow regime is one of the key characteristics of gas-liquid two-phase pipe-flows and its identification is essential for several industrial applications. In this paper, the ultrasonic phased array technology is used to identify flow regimes of two-phase (air-water) vertical flow. The ultrasonic phased array can perform multi-point, omnidirectional detection to obtain high-resolution data suitable for image processing. The scanned images, which have distinctive features, are subjected to a series of image-treatment techniques, such as principle component analysis, to extract information necessary for flow regime identification. The K-nearest neighbors (KNN) classification algorithm is then used to identify flow regimes with high accuracy.

This paper reports the performance of a research prototype of a new multiphase flow instrument to non-invasively measure the phase flow rates, with the capability to rapidly image the flow distributions of two- and three-phase (gas and/or oil in water) flows. The research prototype is based on the novel concepts of combining vector Electrical Impedance Tomography (EIT) sensor (for measuring dispersed phase velocity and fraction) with an electromagnetic flow meter (EMF, for measuring continuous-phase velocity with the EIT input) and a gradiomanometer flow-mixture density meter (FDM), in addition to on-line water conductivity, temperature and absolute pressure measurements. EIT-EMF-FDM data fusion embedded in the research prototype, including online calibration/compensation of conductivity change due to the change of fluids’ temperature or ionic concentration, enables the determination of mean concentration, mean velocity and hence the mean flow rate of each individual phase based on the measurement of dispersed phase distributions and velocity profiles. Results from first flow-loop experiments conducted at Schlumberger Gould Research (SGR) will be described. The performance of the research prototype in flow-rate measurements are evaluated by comparison with the flow-loop references. The results indicate that optimum performance of the research prototype for three-phase flows is confined within the measuring envelope 45%-100% Water-in-Liquid Ratio (WLR) and 0%-45% Gas Volume Fraction (GVF) Within the scope of this joint research project funded by the UK Engineering & Physical Sciences Research Council (EPSRC), only vertical flows with a conductive continuous liquid phase will be addressed.

Oil-in-water two-phase flows are often encountered in the upstream petroleum industry. The measurement of phase flow rates is of particular importance for managing oil production and water disposal and/or water reinjection. The complexity of oil-in-water flow structures creates a challenge to flow measurement. This paper proposes a new method of two-phase flow metering, which is based on the use of dual-modality system and multidimensional data fusion. The Electrical Resistance Tomography system (ERT) is used in combination with a commercial off-the-shelf Electromagnetic Flow meter (EMF) to measure the volumetric flow rate of each constituent phase. The water flow rate is determined from the EMF with an input of the mean oil-fraction measured by the ERT. The dispersed oil-phase flow rate is determined from the mean oil-fraction and the mean oil velocity measured by the ERT cross-correlation velocity profiling. Experiments were carried out on a vertical upward oil-in-water pipe flow, 50 mm inner-diameter test section, at different total liquid flow rates covering the range of 8-16 m3/hr. The oil and water flow rate measurements obtained from the ERT and the EMF are compared to their respective references. The accuracy of these measurements is discussed and the capability of the measurement system is assessed.

The underbalanced drilling technique, which is also known as managed-pressure drilling, is playing an important role in oil and gas sector, as it reduces common conventional drilling problems such as minimal drilling rates and formation damage, differential sticking and lost circulation. Flow regime monitoring is one of the key topics in annular multiphase flow research, particularly for underbalanced drilling technique. Prediction of the prevailing flow regime in an annulus channel is of particular importance in the design and installation of underbalanced drilling facilities. Especially, for establishing a suitable pressure-drop model based on the characteristics of the active flow regime. The methods of flow regime prediction (or visualisation) in an annulus channel that are currently in use are very limited, this is evidently due to poor accuracy or they are simply not applicable to underbalanced drilling operation in practice. Therefore, this paper presents a monitoring method, in which Electrical Resistance Tomography (ERT) is used to rapidly image the prevailing flow regime in an annulus channel with a metallic inner pipe. Experiments were carried out using an air-water flow loop with a test section 50 mm diameter flow pipe. The two-phase air-water flow regimes are visualised in the upward vertical annulus channel with a radius ratio (r/R) 0.4. This paper highlights the visualisation results of only three flow regimes, namely bubble flow, transitional bubble-slug flow and slug flow. The flow regimes are visualised through axial images stacked from 50 mm diameter-pixels of 2D tomograms reconstructed with the Conjugate Gradient Method (SCG). Gas volume fraction profiles within the annulus flow channel are also illustrated. The profiles are extracted using the Modified Sensitivity coefficient Back-Projection (MSBP) method with a sensitivity matrix generated from a realstic phantom in the finite element method software. The results are compared with visual observations (e.g. photographs) of the active flow regime at the time of ERT measurements.

Electrical Impedance Tomography (EIT) is a fast imaging technique displaying the electrical conductivity contrast of multiphase flow. It is increasingly utilised for industrial process measurement and control. In principle, EIT has to obtain the prior information of homogenous continuous phase in terms of conductivity as a reference benchmark. This reference significantly influences the quality of subsequent multiphase flow measurement. During dynamic industrial process, the conductivity of continuous phase varies due to the effects from the changes of ambient and fluid temperature, ionic concentration, and internal energy conversion in fluid. It is not practical to stop industrial process frequently and measure the conductivity of continuous phase for taking the EIT reference. If without monitoring conductivity of continuous phase, EIT cannot present accurate and useful measurement results. To online calibrate the electrical conductivity of continuous phase and eliminate drift error of EIT measurement, two methods are discussed in this paper. Based on the linear approximation between fluid temperature and conductivity, the first method monitors fluid temperature and indirectly calibrates conductivity. In the second method, a novel conductivity cell is designed. It consists of a gravitational separation chamber with refreshing bypass and grounded shielding plate. The conductivity of continuous phase is directly sensed by the conductivity cell and fed to EIT system for online calibration. Both static and dynamic experiments were conducted to demonstrate the function and accuracy the conductivity cell.

Facilitated transport of K+ ions through membranes is of great significance in both science and technology for the efficient and selective separation of potassium ions. Here, a novel membrane with ion-recognizable copolymers in graphene-based nanochannels is developed for facilitated transport of potassium ions. The poly(N-isopropylacrylamide-co-benzo-15-crown-5-acrylamide) (PNB) copolymers are fixed in the lamellate spacings between the partially reduced graphene oxide (prGO) nanosheets. The K+ permeability of the fabricated prGO-PNB membrane remarkably increases at around the lower critical solution temperature (LCST) of the PNB copolymer, because of the dynamic complexation between B15C5 units and K+ ions at around the LCST. The selectivity of K+/Na+ increases with increasing the content of PNB copolymers in the membrane. The proposed membrane shows good stability in water and K+ separation performance. Due to the uniform channels and facilitated transport mechanism of the prGO-PNB membrane, the comprehensive performance of selectivity and permeability of the K+ ions is better than that of previously reported polymer-based nanofiltration membranes, polymer-based facilitated transport membranes and graphene-based membranes. The proposed strategy of this prGO-PNB membrane that combining graphene-based sheets as “skeleton” and substance-recognizable copolymers as “facilitators” is also applicable to fabricate membranes for facilitated transport of other ions or molecules.

In this paper, chitosan microcapsules with stable nano-membranes for controlled release of drugs are prepared by a simple one-step microfluidic strategy from oil-in-water (O/W) single emulsion templates. The ultrathin membranes of microcapsules are formed at the interface of the O/W emulsion droplets via the interfacial reaction between chitosan in aqueous phase and terephthalaldehyde in oil core. The membrane thickness can be effectively controlled within 10 nm and accurately regulated at nanoscale from 2.8 nm to 8.0 nm by adjusting the crosslinking time, concentrations of reactant and viscosity of aqueous solution. Among these factors, the membrane thickness is more susceptible to the viscosity of aqueous phase. The stability of the nano-membranes is quite good, which makes the microcapsules exhibit excellent structure integrity during 150 days. Using tea tree oil (TTO) as the model drug, the prepared chitosan microcapsules with nano-membranes show low mass transfer resistance and rapid drug release. The cumulative release rate of TTO from chitosan microcapsules with membrane thickness of 3.1 nm and 4.3 nm reach to 76.1% and 56.6% within 10 h, respectively. The drug release behaviors from the chitosan microcapsules are directly related to the thickness of the capsule membranes, and therefore can also be finely controlled. The thinner the capsule membrane is, the faster the drug release. The initial TTO release rate doubles as the membrane thickness decreases from 4.3 nm to 3.1 nm. In addition, because no surfactant is used in the whole preparation process, the prepared chitosan microcapsules present satisfactory biocompatibility. The results provide valuable guidance for designing and fabricating polymeric microcapsule membranes with controllable nanoscale thickness to enhance their performances in biological and medical applications.

The occurrence of separation and slippage of the two phases in settling solid-liquid flow in pipelines make the flow unpredictable and time dependent. Therefore it is paramount for the operator of slurry pipelines to monitor and measure the flow continuously, particularly from the local point of view. This paper reports the laboratory experiments carried out on an open flow loop and the use of Electrical Resistance Tomography (ERT) to interrogate the internal structure of horizontal and vertical counter-gravity slurry flow. The use of high performance dual-plane ERT system, which is called Fast Impedance Camera System (FICA), is attempted for fast impedance measurement of the media with a temporal resolution up to 1000 dual-frames per second (dfps). The internal images of the pipeline are captured along with the measurement of solids volumetric concentration for both orientations, while the dualplane ERT is combined with cross-correlation technique to estimate axial solids velocity distribution. A set of experiments was carried out on coarse and medium sand-water slurry flow with 2% and 10% throughput volumetric concentration and the transport velocity range of 1.5-5 m/s. A flow diversion technique was used for validation of mean local solids concentration and solids axial velocity obtained from the ERT.

Two-phase slurry flow is encountered in many industries such as petroleum, mining and related industries. The abrasiveness of slurry and interaction of solid particles with the carrier liquid make slurry flow measurement one of the most challenging applications in multi-phase flow metering. This paper presents a new method of solid-liquid flow metering, in which the Electrical Resistance Tomography (ERT) is used in combination with a commercial Electromagnetic Flow Meter (EMF) to measure the volumetric flow rate of each phase. A set of experiments were carried out using a mixture of sand particles and tap water as slurry. Two different sand types (coarse and medium), with a particle size range of 53-2330μm, were pumped through a 50mm inner-diameter pipeline. The range of throughput solids concentration used in the experiments was 5%-10% and operated the transport velocity was 2-5 m/s. The effect of solids concentration and solids velocity on the measurement scheme is discussed. The measurement results are compared to that of Coriolis mass flow meter and discharge flow measurement system (flow diversion system). The accuracy of the measurement results is assessed and the performance of the applicability of the proposed method is highlighted.

Flow regime recognition is not only useful for characterisation of the flow, but also for the purpose of modeling, system controls and optimization and correction of flow regime dependent flow meters. This paper proposes a new indirect method for on-line recognition of the active horizontal slurry flow regime using statistical signal analysis of measurements obtained with a high performance Electrical Resistance Tomography system (ERT). Significant features of the ERT signal are extracted from both time domain and frequency domain. A set of experiments were carried out using a pilot-scale slurry flow loop, through which a mixture of sand and tap water was pumped into a 50 mm inner-diameter test section. All common slurry flow regimes are considered in the recognition scheme, including the transitional regime boundaries covering the transport velocity range of 1.5-5 m/s. Two types of sand are used in the experiments, medium (75-900 μm) and coarse (150-2200 μm), each with different throughput volumetric concentration, 2% and 10%. 1.2 m transparent pipe section was included into the test section, so as to visually inspect the prevailing flow regime and capture photographic images of the flow. A code was developed not only to render the recognition of the active flow regime, but also to visualise the distribution of the solid particles across the pipe cross-section and display the mean solids volume fraction. The evaluation of the proposed recognition method suggests 90.32% successful rate.