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Rational design and synthesis of molecular sieving, photocatalytic, hollow fiber membranes for advanced water treatment applications

Rational design and synthesis of molecular sieving, photocatalytic, hollow fiber membranes for advanced water treatment applications

In this study, the syntheses of the composite hollow fibers were optimized for physicochemical, mechanical and photocatalytic properties by changing the calcination temperatures (500 to 1000 °C for 8 h) followed by times (2 to 8 h at 600 °C). It was found that by increasing the calcination temperature from 500 to 900 °C that the hollow fibers show a decreasing trend in bending modulus and photocatalysis. This was respectively due to the effect of thermal decomposition of the polymer binder and thermally-induced transformation of anatase to rutile phases of the titania nanoparticles. By limiting the calcination temperature to 600 °C, it was demonstrated that the hollow fiber membranes displayed multi-functional properties. The titania nanoparticles within these hollow fibers retained a high proportion of the anatase phase whilst the polymer binder was partially decomposed and pyrolyzed to form an amorphous, microporous carbon, which not only enhanced the surface area and pore volume, but also overcoming the trade-off between the bending modulus (~34 MPa) and photocatalytic degradation (> 90%) of AO7. The membrane performance of optimized photocatalytic hollow fibers (600-3h and 600-6h) were found to fully reject AO7 whilst producing purified water in the permeate stream via molecular-sieving process. The 600-3h membrane achieved the highest water fluxes of 6.9 (H 2 O/dark), 12.9 (H 2 O/UV) 4.8
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A Comparative Study on the Application of Porous PES and PEI Hollow Fiber Membranes in Gas Humidifcation Process

A Comparative Study on the Application of Porous PES and PEI Hollow Fiber Membranes in Gas Humidifcation Process

The objective of this study is to apply two different polyetherimide (PEI) and polyethersulfone (PES) hollow fiber membranes in gas humidification process and comparing their performance at various operating conditions and study the effect of operating parameters on the water vapor flux. PEI and PES membranes have good thermal and chemical resistance and have been applied in membrane gas absorption process [25, 26] which showed reasonable results; therefore it is expected that PEI and PES membranes present suitable performance in humidification process. Furthermore, comparing the characteristics of membranes provides the criteria to find the ones that govern the performance of the membrane in the humidification process.
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Electrospun fiber membranes enable proliferation of genetically modified cells

Electrospun fiber membranes enable proliferation of genetically modified cells

Briefly, cells were synchronized with 6 µ M aphidicolin followed by 4 hours of release prior to introduction of the 3 ′ PTO (phosphorothioate)-modified 72-nucleotide (NT) single- stranded oligodeoxynucleotide (ssODN) by electroporation. One million cells in 100 µL of Hyclone McCoy’s 5A serum free medium (Thermo Scientific, Logan, UT, USA) were mixed with the ssODN (4 µ M) in an electroporation cuvette with a 4 mm gap (Fisher Scientific, Hampton, NH, USA). The cells were electropermealized using a Gene Pulser Xcell™ electroporation apparatus (Bio-Rad, Hercules, CA, USA) with settings of 250 V, 13 ms, 2 pulses, and a 1-second interval for delivery of ssODN into the cells. Immediately after the electroporation, the cells were transferred onto nanofibers for recovery and growth. Triplicate samples of cells recovered on fiber membranes were harvested at Day 4 (96 hours) and Day 7 (168 hours) for analysis of gene editing using fluorescence-activated cell-sorting (FACS) analysis (Guava EasyCyte HT, Millipore, Billerica, MA, USA). The corrected cells on the fibers at Day 4 (96 hours) were visualized and images were taken using an EVOS FL microscope (AMG Micro, Bothell, WA, USA). 37
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Fabrication of Crosslinkable Hollow Fiber Membranes for Pervaporation Dehydration

Fabrication of Crosslinkable Hollow Fiber Membranes for Pervaporation Dehydration

Integrally-skinned asymmetric Polyetherimide/Poly (vinyl alcohol) (PEI/PVA) hollow fiber membranes for pervaporation dehydration were fabricated by non-solvent induced phase inversion. PVA inside the PEI matrix could be crosslinked to provide membrane performance stability during long term operation. The effects of different PEI/PVA blend ratio, external coagulant type and flow rate, and crosslinking conditions on the membrane structure and the separation performance were investigated. Generally, hollow fibers using PEI/PVA blend are less selective than those of neat PEI, probably due to the defects evolved between PEI and PVA. The influence of coagulant type on membrane pervaporation performance was specific to dope formulation; when using n-butanol as external coagulant, the higher the coagulant flow rate, the better the membrane separation performance. PVA crosslinking by maleic acid (MA) enhanced the membrane performance, obviously. PEI/PVA Hollow fibers formed using n-butanol as external coagulant obtained a separation factor of 28 after crosslinking, much better than 4.4 with the original one. The crosslinked membrane exhibited higher stability than the neat PEI membrane. The separation factor of the latter degraded by more than half after around 200 h operation. Finally, this work has provided a new approach for fabricating crosslinkable asymmetric membrane suitable for pervaporation dehydration.
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An Experimental Study on the Oily Wastewaters Treatment by Polyethersulfone (PES) Nanostructure Hollow Fiber Membranes

An Experimental Study on the Oily Wastewaters Treatment by Polyethersulfone (PES) Nanostructure Hollow Fiber Membranes

Oily wastewaters from oil refineries and oil distribution centers are one of the most important environmental concerns in recent decades; therefore, it is critical to treat these types of wastewaters. In this study, the performance of different polyethersulfone hollow fiber membranes in oily wastewaters treatment was investigated and the effects of operating conditions such as transmembrane pressure, oil concentration in the feed and feed cross flow velocity (CFV) on the membrane performance were studied. Increasing the pressure makes more membrane compactness and higher membrane fouling; as a result, higher pressure reduces the membrane performance. The optimum operating conditions for oily wastewaters separation are P = 1 bar, low feed concentration (300 ppm) and high feed cross flow velocity (0.18 m s -1 ). In this
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Clarification of factors that affect the 
		flux performance of Hollow Fiber membranes during Ultra filtration using 
		Design of Experiments

Clarification of factors that affect the flux performance of Hollow Fiber membranes during Ultra filtration using Design of Experiments

In conclusion, the use of the statistical DOE method to develop a flux model for hollow fiber membranes during the ultrafiltration process has been illustrated in this study. The derived empirical model can be subsequently used for predicting the flux value within the separation region. A half fractional factorial experiment was conducted and the results based on ANOVA show that the pH and temperature of feed solution, time of separation process and transmembrane pressure are significant factors on the flux performance of hollow fiber membranes. For future work, the response surface methodology will be used to get the optimum solution since the ANOVA results show the curvature is significant. The experimental results of this study can help to maximize the flux performance of hollow fiber membranes, thus contributing to a more sustainable filtration system.
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Latest development of carbon hollow fiber membranes for gas separation

Latest development of carbon hollow fiber membranes for gas separation

especially carlnn membrane has emerged as anothei :itemative membrane in the separation t€chnology. Generallv- inorganic membmnesian be dividcd into two diilerent categoriesi pot[r]

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Quality of Kiwifruit Juice Clarifed by Modifed Poly(Ether Ether Ketone) Hollow Fiber Membranes

Quality of Kiwifruit Juice Clarifed by Modifed Poly(Ether Ether Ketone) Hollow Fiber Membranes

Membrane-based processes, such as microfiltration (MF) and ultrafiltration (UF), represent a valid alternative to the use of traditional fining agents and filter aids [15]. MF and UF membranes retain large species such as microorganisms, lipids, proteins and colloids, while small solutes such as vitamins, salts and sugars flow together with water. Advantages over conventional fruit juice processing are in terms of increased juice yield; possibility of operating in a single step reducing working times; possibility of avoiding the use of gelatines, adsorbents and other filtration aids; reduction in enzyme utilisation; easy cleaning and maintenance of the equipment; reduction of waste products; elimination of needs for pasteurisation. In addition, the low temperatures used during the process preserve the fruit juice freshness, aroma and nutritional value [16, 17].
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Application of Salt Additives and Response Surface Methodology for Optimization of PVDF Hollow Fiber Membrane in DCMD and AGMD Processes

Application of Salt Additives and Response Surface Methodology for Optimization of PVDF Hollow Fiber Membrane in DCMD and AGMD Processes

assembling, scale-up and maintenance in MD applications [7,9]. Most studies focused on the preparation of hollow fiber membranes by the dry/wet spinning or the wet spinning techniques [10-16]. Although the production of fibers is more complex, it involves more controlling parameters including the nature and concentration of the polymer, additives in polymer solution, temperature of internal and external coagulants, spinneret dimensions, injection rate of the polymer solution, internal coagulant, air gap length and take-up speed [17-22]. The proper design of statistical experiments shows that we can study more parameters at the same time and gain maximum information from the limited experimental data contrary to the conventional spinning approach based on trial and error [23-27].
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Fabrication and Modification of Thin-Film Composite Hollow Fiber NF Membranes

Fabrication and Modification of Thin-Film Composite Hollow Fiber NF Membranes

Thin-film composite hollow fiber membranes were prepared by interfacial polymerization of Piperazine in aqueous phase with TMC in organic phase (i.e. n-hexane). The concentration of additives in the aqueous phase are given in Table 2. The PSF hollow fiber support membrane was submerged into the aqueous phase for 90 s. Subsequently, the membrane was taken out to drain off the excess monomers for 1 min. The amine saturated membrane was again immersed into the organic phase containing 0.5% (w/v) TMC in n-hexane where the conventional IP reaction took place. Afterward, the membrane was taken out and air-dried at 70 °C for 4 min. The dipping process had been carried out such a way that only the external surface has come in contact with reactants to form polyamide skin layer.
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Surface modified hollow fiber membrane contactor for carbon dioxide absorption and desorption

Surface modified hollow fiber membrane contactor for carbon dioxide absorption and desorption

liquid into membrane pores should be prevented as pore wetting reduces the mass transfer in contactor significantly and makes it less competitive compared to the conventional column. One cause of pore wetting is capillary condensation (Mavroudi et al. 2006), but more importantly the pressure of the feed liquid should surpass a critical value for the liquid to enter into push the liquid pores. This critical value, called liquid entry pressure of water, depends on some properties of membrane such as pore size, hydrophobicity, surface roughness and chemical resistance to solvent (Dindore et al. 2004) and also, on the surface tension of solvent and operating conditions of absorption process. Thus, it is possible to reduce the wettability of membranes by decreasing pore size and using membranes of high hydrophobic surface. In hollow fiber membrane contactor furthermore hydrophobicity, pore size is important as well. Hollow fiber membranes with very small pore size show low mass transfer flux due to lower interfacial surface of gas and liquid. Therefore, in order to decreasing wettability of membrane and increasing mass transfer flux, this is essential to fabricate hollow fiber membrane with high hydrophobic surface and large pore size.
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Preparation and characterization of polyethylene/ glass fiber composite membrane prepared via thermally induced phase separation method

Preparation and characterization of polyethylene/ glass fiber composite membrane prepared via thermally induced phase separation method

In this study, grinded glass fiber embedded HDPE membranes were prepared via thermally induced phase separation method. The results from this study showed that all of the membranes had leafy structure, indicat- ing a solid-liquid mechanism during phase separation. The existence of glass fibers in the membranes’ matrix and their uniform dispersion were confirmed by EDX and TGA analyses. It was shown that glass fiber im- proved the antifouling properties of the membranes. The HDPE/glass fiber membranes showed a higher water flux and a lower flux decline during filtration of BSA solution compared to the neat HDPE membranes. These findings were attributed to the hydrophilicity of glass fiber. The results of abrasion test with sili- con carbide slurry revealed that the glass fiber/HDPE membranes were more abrasion resistant than the neat HDPE membrane. Tensile strength of the composite membranes before and after abrasion test was also higher than that of the neat HDPE membrane. There- fore, glass fiber embedded HDPE membranes are suit- able candidate for water treatment application.
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Thin Film Composite and/or Thin Film Nanocomposite Hollow Fiber Membrane for Water Treatment, Pervaporation and Gas/Vapor Separation

Thin Film Composite and/or Thin Film Nanocomposite Hollow Fiber Membrane for Water Treatment, Pervaporation and Gas/Vapor Separation

PRO can be viewed as an intermediate process between FO and RO, where hydraulic pressure is applied in the opposite direction of the osmotic pressure gradient (similar to RO). Loeb and Norman [36] proposed pressure-retarded osmosis (PRO) process. In a PRO process, water flows naturally from a low salinity stream (feed water) at an ambient pressure across a semi-permeable membrane to a pressurized high salinity stream (draw solution) driven by the osmotic pressure difference across the membrane. Chou et al. [37] first time reported the fabrication of thin-film composite hollow fiber membranes which could be used in PRO process. Composite hollow fiber membrane was prepared by depositing a thin layer of PA on PES hollow fiber via IP. The main reagents used were m-phenylenediamine (MPD), trimesoyl chloride (TMC) and cyclohexane. From the performance test, it was revealed that The TFC PRO hollow fiber membranes have a water permeability (A) of 9.22 × 10 −12 m/(s Pa), salt permeability (B) of 3.86 × 10 −8 m/s and structural
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Preparation and characterization of novel PSf/PVP/PANI-nanofiber nanocomposite hollow fiber ultrafiltration membranes and their possible applications for hazardous dye rejection

Preparation and characterization of novel PSf/PVP/PANI-nanofiber nanocomposite hollow fiber ultrafiltration membranes and their possible applications for hazardous dye rejection

Hollow fiber membranes show increased water flux when compared to flat sheet membranes since they have a higher surface area per unit of membrane module volume. The membrane cross-flow filtration tests indicate that, flux increases with increasing PANI- nanofiber concentration for constant pressure of 2 bar as shown in Fig.9. The higher water flux for new membranes can be attributed to increased hydrophilicity and increased porosity due to PVP and PANI-nanofiber additives. The nanocomposite membrane showed increased flux and rejection due to the additives. The PANI-nanofibers are hydrophilic in nature and during the membrane formation process, they migrate towards the surface of the membrane [30]. This migration through the polymer matrix, forms finger like interconnected pores in the membrane cross section. This increases flux and reduces resistance to flow of water through the membrane Also, due to the hydrophilic PANI-nanofibers moving to the surface, the membrane surface becomes more hydrophilic and this in turn increases wetting of the surface contributing to the increase in flux. PVP has been used as a pore forming agent and is reported to increase the formation of pores on the membrane surface [31] thus increasing flux of water through the membrane. Also, since PVP is a water-soluble polymer, it may be leached out from the polymer matrix when the membrane is immersed in water, causing the formation of micro voids and thereby increasing the porosity of the membrane [36].
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Ionic liquid loaded hollow fiber membrane as a solid phase microextraction fiber; application in determination of aromatic
hydrocarbons in water samples

Ionic liquid loaded hollow fiber membrane as a solid phase microextraction fiber; application in determination of aromatic hydrocarbons in water samples

Benzene, toluene, ethylbenzene, Xylene isomers, acetone, hydrogen chloride, 2-propanol, ethyl acetate, sodium chloride and acetonitrile were all obtained from Merck (Darmstadt, Germany). 1-vinyl imidazole, hexyl chloride, sodium hexafluorophosphate, methyltrimethoxysilane (MTMOS) and tetramethoxysilane (TMOS) were purchased from Sigma-Aldrich (St. Louis, USA). The 50/280 Accurel polypropylene hollow fiber membranes (280 µm I.D.) from Membrana GmbH (Wuppertal, Germany) were used. Nitrogen and hydrogen (99.999 % purity) were obtained from the Sabalan Oxygen Co. (Tehran, Iran). Copper wire was purchased from a local electronic shop and used after removing insulation.
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Ultrastructural Pathology of Plasma and Endoplasmic
Reticulum Membranes of Nerve and Glial Cells: A Review

Ultrastructural Pathology of Plasma and Endoplasmic Reticulum Membranes of Nerve and Glial Cells: A Review

Autophagy and apoptosis are basic physiologic processes contributing to the maintenance of cellular homeostasis. Autophagy encompasses pathways that target long-lived cytosolic proteins and damaged organelles. It involves a sequential set of events including double membrane formation, elongation, vesicle maturation and finally delivery of the targeted materials to the lysosome. Deregulation of autophagy plays a pivotal role in the etiology and/ or progress of many neurodegenerative disorders [62]. Neurons employ specialized mechanisms to modulate local gene expression in dendrites, via the dynamic regulation of micro RNA biogenesis factors at intracellular membranes of the endoplasmic reticulum, which in turn is crucial for neuronal dendrite complexity and therefore neuronal circuit formation and function.
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Power Spectral Analysis Of Surface EMG Of Surface EMG For Weight Lifting Atheletes

Power Spectral Analysis Of Surface EMG Of Surface EMG For Weight Lifting Atheletes

EMG is an experimental technique concerned with the improvement, recording and examination of myoelectrical sign or EMG sign create by the physical varieties in the condition of muscle fiber layers. This sign can be utilized as an assessment apparatus for applied research, physiotherapy, rehabilitation, and sports training. It is similar to what are the muscle doing in certain point with specific situations [1, 2].

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Energy absorption performance of conical natural fiber reinforced composites Abstract

Energy absorption performance of conical natural fiber reinforced composites Abstract

Natural fiber-reinforced composites have attracted increasing interest because of the advantages of fibers, such as low density, relatively high toughness, high strength and stiffness, good thermal properties and biodegradability. This present work used coconut coir as reinforcing tool in plastic composite. Different cone parameter and fiber volume fractions are produced and tested. The cone is compressed quasi-statically and force-displacement diagram is recorded for each case, then specific energy absorption performance is calculated and compared. It is shown that fiber volume fractions and cone parameter such vertex-angle, upper and lower diameter have controlled the cone performance. Most of the conical composites collapsed progressively under axial compressive loading.
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αA-crystallin R49Cneomutation influences the architecture of lens fiber cell membranes and causes posterior and nuclear cataracts in mice

αA-crystallin R49Cneomutation influences the architecture of lens fiber cell membranes and causes posterior and nuclear cataracts in mice

defects in the deep cortical fiber cells approximately 100 μm from the lens surface that result in gaps between adja- cent fiber cells. Visible swelling or vacuolar areas are often limited to one or more segments of a fiber cell; hence it is likely that there are many more aberrant fiber cells than those observed in a single mid-sagittal section. Vacuolated cells indicate destruction of the fiber cells. Further studies are necessary to determine whether these vacuolar or swollen cells are formed by membrane rupture and fusion of cytoplasmic contents from multiple cells. This type of fiber cell swelling has been reported in diabetic and other models of cataract [61,62]. Membrane defects have also been shown to be associated with lens opacities induced by dexamethasone and mechanical stress in cultured lenses, both of which are associated with the loss of cad- herin junctions [17,63]. The interaction between αA-crys- tallin and fiber cell membranes is well-established [16,64,65], and has been shown to increase with lens Morphological alterations in lenses from older wild type and R49C neo /R49C neo knock-in mice
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A review of material development in the field of carbon capture and the application of membrane-based processes in power plants and energy-intensive industries

A review of material development in the field of carbon capture and the application of membrane-based processes in power plants and energy-intensive industries

72% was achieved for short periods when all process pa- rameters were well controlled in the single-stage FSC membrane system [49]. The membrane efficiency of the plate-and-frame module was quite low, and the designed system suffered significant water condensation/corrosion issues. Thus, the hollow fiber FSC membrane modules with total membrane area of ca. 20 m 2 were constructed by the joint force from Air Products and Chemicals, Inc., in 2016 [51]. In that project, the pilot FSC membrane sys- tem was evaluated at TRL 5. The system was tested over 6 months at different conditions, and stable performance was found even at a high NO x and SO 2 loading (average
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