scholarly journals Fabrication technique of composite chitosan/alginate membrane module for greywater treatment

2021 ◽  
Vol 2120 (1) ◽  
pp. 012037
Author(s):  
S Nalatambi ◽  
K S Oh ◽  
L W Yoon
Keyword(s):  
Composite Membrane ◽  
Water Flux ◽  
The Other ◽  
Fabrication Technique ◽  
Pathogen Removal ◽  
Dense Structure ◽  
Alginate Solution ◽  
Mixing Speed ◽  
Significant Performance ◽  
Improved Characteristics

Abstract A novel chitosan/alginate composite membrane is proposed for the application of greywater treatment. In particular, the effect of stirring speed of mixing chitosan and alginate solution was investigated in this study. The study revealed that 150CSAL and 210CSAL membranes swell significantly compared to CS membrane due to the porous structure of composite membrane. The FTIR spectra revealed that the mixing speed has no influence in terms of molecular interaction between CS and AL due to fixed CS and AL concentrations used in this study. On the other hand, the complexation of AL with CS made outstanding improvement to the dense structure of CS where 180CSAL membrane has UP water flux as high as 90 L/m2h at 2 bar. All membranes have the capability to remove the pollutants present in GW and the COD removal was further improved up to 7% using CSAL membranes. In addition, increasing mixing speed improved the pathogen removal efficiency compared to CS membrane. The treated GW met the non-potable GW reuse standard for turbidity<5 NTU and TSS<20 mg/L. To summarize, the proposed fabrication technique on CSAL membrane showed improved characteristics to CS membrane and has significant performance on GW treatment.

scholarly journals OBSERVATIONS ON THE FINE STRUCTURE OF THE DEVELOPING SPERMATID IN THE DOMESTIC CHICKEN

1962 ◽  
Vol 14 (2) ◽  
pp. 193-205 ◽  
Author(s):  
Toshio Nagano
Keyword(s):  
Plasma Membrane ◽  
Fine Structure ◽  
Cross Section ◽  
Neck Region ◽  
Structural Features ◽  
Dense Granule ◽  
Domestic Chicken ◽  
The Other ◽  
Dense Structure ◽  
Distal Centriole

The kinetic apparatus, the acrosome and associated structures, and the manchette of the spermatid of the domestic chicken have been studied with the electron microscope. The basic structural features of the two centrioles do not change during spermiogenesis, but there is a change in orientation and length. The proximal centriole is situated in a groove at the edge of the nucleus and oriented normal to the long axis of the nucleus and at right angles to the elongate distal centriole. The tail filaments appear to originate from the distal centriole. The plasma membrane is invaginated along the tail filaments. A dense structure which appears at the deep reflection of the plasma membrane is identified as the ring. The fine structure of the ring has no resemblance to that of a centriole and there is no evidence that it is derived from or related to the centrioles. The tail of the spermatid contains nine peripheral pairs and one central pair of tubular filaments. The two members of each pair of peripheral filaments differ in density and in shape: one is dense and circular, and the other is light and semilunar in cross-section. The dense filaments have processes. A manchette consisting of fine tubules appears in the cytoplasm of the older spermatid along the nucleus, neck region, and proximal segment of the tail. The acrosome is spherical in young spermatids and becomes crescentic and, finally, U-shaped as spermiogenesis proceeds. A dense granule is observed in the cytoplasm between acrosome and nucleus. This granule later becomes a dense rod which is interpreted as the perforatorium.

Ultrahigh-flux and fouling-resistant membranes based on layered silver/MXene (Ti3C2Tx) nanosheets

2018 ◽  
Vol 6 (8) ◽  
pp. 3522-3533 ◽  
Author(s):  
Ravi P. Pandey ◽  
Kashif Rasool ◽  
Vinod E. Madhavan ◽  
Brahim Aïssa ◽  
Yury Gogotsi ◽  
...  
Keyword(s):  
Composite Membrane ◽  
Organic Molecules ◽  
Water Flux ◽  
High Water ◽  
High Rejection

The 21% Ag@MXene composite membrane demonstrated an ultra-high water flux of 420 L m−2h−1bar−1and high rejection efficiency for organic molecules with excellent flux recovery.

Composite Membrane with a Calixarene-Containing Polyamide Functional Layer

2018 ◽  
Vol 71 (5) ◽  
pp. 360 ◽  
Author(s):  
Shun Ren ◽  
Dong-Qing Liu ◽  
Rui-Xiang Miao ◽  
Ze-Xian Zhu ◽  
Yu-Feng Zhang
Keyword(s):  
Composite Membrane ◽  
Photoelectron Spectroscopy ◽  
Interfacial Polymerization ◽  
Film Formation ◽  
Pure Water ◽  
Water Flux ◽  
Metal Cations ◽  
Heat Treating ◽  
Skin Layer ◽  
Functional Layer

Monolayer thin films were prepared at the interface of hexane and water to investigate the film formation ability of monomers through interfacial polymerization (IP). A tetra-calix[4]arene chloride derivative (CC) and a diamino-terminated PEG-1000 (DAP) produced a high strength membrane among the tested monomers. IP is consequently proposed to prepare a composite membrane with CC and DAP on a polysulfone (PSF) bulk membrane used for ultrafiltration. The top layer was cross-linked by heat-treating at 60°C for 2 min, with DAP (2 wt.-%) in water and CC (0.05 wt.-%) in hexane. Attenuated total reflectance (ATR)-FTIR and X-ray photoelectron spectroscopy data confirmed that a polyamide was formed on the surface of the PSF substrate. The skin layer was a 3 μm thick smooth thin-film as determined by field emission scanning electron microscopy (FE-SEM), and was also compact without gaps. Pure water flux was ~80.5 L m−2 h−1 under 0.5 MPa. Rejection of MgSO4 was round 22 %, since the calixarene-containing network was a sparse grid, and also had an affinity for metal cations. Although the skin of the composite membrane was compact under SEM, it was easy for metal cations to transfer through. This composite membrane might have good performance in other separation areas as a result of the special structure imparted by using the calixarenes as cross-linking knots.

scholarly journals Antifouling Polyethersulfone-Petrol Soot Nanoparticles Composite Ultrafiltration Membrane for Dye Removal in Wastewater

Membranes ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 361
Author(s):  
Nkechi P. Nwafor ◽  
Richard M. Moutloali ◽  
Keneiloe Sikhwivhilu ◽  
Oluwole B. Familoni ◽  
Luqman A. Adams
Keyword(s):  
Composite Membrane ◽  
Membrane Filtration ◽  
Dye Removal ◽  
Pure Water ◽  
Water Flux ◽  
Composite Membranes ◽  
Water Remediation ◽  
Blue Dye ◽  
Phase Inversion Technique ◽  
Pure Water Flux

Engineered nanoparticles are known to boost membrane performance in membrane technology. Hitherto, tunable properties that lead to improved hydrophilicity due to increased surface oxygen functionalities upon oxidation of petrol soot have not been fully exploited in membrane filtration technology. Herein, the integration of oxidized petrol soot nanoparticles (PSN) into polyethersulfone ultrafiltration membranes produced via phase inversion technique for dye removal in wastewater is reported. The nanoparticles, as well as the composite membranes, were characterized with diverse physicochemical methods, particularly TEM, SEM, BET, AFM, contact angle, etc. The effect of varying the ratio of PSN (0.05–1.0 wt %) on the properties of the composite membrane was evaluated. The composite membranes displayed increased hydrophilicity, enhanced pure water flux, and antifouling properties relative to the pristine membrane. For example, the obtained pure water flux increased from 130 L·m−2·h−1 for base membrane to 265 L·m−2·h−1 for the best composite membrane (M4). The best flux recovery ratio (FRR) observed for the membranes containing PSN was ca. 80% in contrast to 49% obtained with the pristine membrane indicative of the positive influence of PSN on membrane antifouling behavior. Furthermore, the PSN composite membranes displayed relatively selective anionic dye rejection of ˃95% for Congo red and between 50–71% for methyl orange compared with 42–96% rejection obtained for cationic methylene blue dye with increasing PSN content. The successful fabrication of polyethersulfone–PSN composite membranes by a simple blending process opens a novel route for the preparation of economical, functional, and scalable water purification membranes capable of addressing the complex issue of water remediation of organic azo dyes.

Varieties of Object Constancy

1989 ◽  
Vol 41 (4) ◽  
pp. 775-796 ◽  
Author(s):  
R. Ellis ◽  
D. A. Allport ◽  
G. W. Humphreys ◽  
J. Collis
Keyword(s):  
Stimulus Onset Asynchrony ◽  
Response Latency ◽  
Stimulus Onset ◽  
Decision Time ◽  
The Other ◽  
Performance Decrement ◽  
Single Object ◽  
Significant Performance ◽  
Angle Of View ◽  
Onset Asynchrony

Three experiments are described in which two pictures of isolated man-made objects were presented in succession. The subjects’ task was to decide, as rapidly as possible, whether the two pictured objects had the same name. With a stimulus-onset asynchrony (SOA) of above 200 msec two types of facilitation were observed: (1) the response latency was reduced if the pictures showed the same object, even though seen from different viewpoints (object benefit); (2) decision time was reduced further if the pictures showed the same object from the same angle of view (viewpoint benefit). These facilitation effects were not affected by projecting the pictures to different retinal locations. Significant benefits of both types were also obtained when the projected images differed in size. However, in these circumstances there was a small but significant performance decrement in matching two similar views of a single object, but not if the views were different. Conversely, the object benefit, but not the viewpoint benefit, was reduced when the SOA was only 100 msec. The data suggest the existence of (at least) two different visual codes, one non-retinotopic but viewer-centred, the other object-centred.

scholarly journals Eradication of Plant Pathogens in Forest Nursery Irrigation Water

Plant Disease ◽  
2013 ◽  
Vol 97 (6) ◽  
pp. 780-788 ◽  
Author(s):  
Patrícia da S. Machado ◽  
Acelino C. Alfenas ◽  
Marcelo M. Coutinho ◽  
Cláudio M. Silva ◽  
Ann H. Mounteer ◽  
...  
Keyword(s):  
Irrigation Water ◽  
Chemical Treatment ◽  
Plant Pathogens ◽  
The Other ◽  
Forest Nursery ◽  
Pathogen Removal ◽  
Rooted Cuttings ◽  
Xanthomonas Axonopodis ◽  
Physical Chemical ◽  
Forest Nurseries

Interest in rational use and reuse of water has increased in recent years, especially in forest nurseries. However, before water can be reused in nurseries, it must be properly treated to eradicate plant pathogens to reduce risks of pathogen dispersal and losses to disease. In the present study, the efficacy of irrigation water treatment by ultrafiltration and conventional physical-chemical treatment was studied to eliminate Botrytis cinerea, Cylindrocladium candelabrum, Ralstonia solanacearum, and Xanthomonas axonopodis, the pathogens most commonly found in Brazilian forest nurseries. Ultrafiltration eradicated over 99% of R. solanacearum, X. axonopodis, and B. cinerea and 100% of C. candelabrum. The few remaining cells or conidia of R. solanacearum and B. cinerea did not induce disease in irrigated rooted cuttings. Flocculation and fast sand filtration used in physical-chemical treatment completely eliminated C. candelabrum but the other pathogens were only removed after chlorination of the filtered water. Both forms of treatment are viable, practical, and safe methods for plant pathogen removal from irrigation water.

Effects of some respiratory inhibitors on water flux in root hairs of Avena sativa

1972 ◽  
Vol 50 (3) ◽  
pp. 575-579 ◽  
Author(s):  
Mukhtar Ahmad ◽  
Marcel Cailloux
Keyword(s):  
Water Uptake ◽  
Avena Sativa ◽  
Water Flux ◽  
Root Hairs ◽  
Potassium Cyanide ◽  
Intimate Relationship ◽  
The Other ◽  
Respiratory Metabolism ◽  
Respiratory Inhibitors ◽  
Low Concentrations

Effects of potassium cyanide, sodium azide, and sodium fluoride on water uptake by root hairs of Avena sativa have been investigated. Low concentrations (2 × 10−6 and 2 × 10−5 M) of potassium cyanide accelerate the velocity of water uptake; a decline in the magnitude of water uptake is observed at 2 × 10−4 M and 55% inhibition at 2 × 10−3 M.Azide and fluoride, on the other hand, convert excretion into absorption when applied at low concentrations (3 × 10−4 M and 6 × 10−6 M, respectively) while at increased inhibiting concentrations absorption may be converted into excretion without causing the death of the root hairs.The evidence presented strongly suggests an intimate relationship between respiratory metabolism and absorption of water.

scholarly journals Cell biology and physiology of the uroepithelium

2009 ◽  
Vol 297 (6) ◽  
pp. F1477-F1501 ◽  
Author(s):  
Puneet Khandelwal ◽  
Soman N. Abraham ◽  
Gerard Apodaca
Keyword(s):  
Ion Channels ◽  
High Resistance ◽  
Barrier Function ◽  
Cell Biology ◽  
Apical Membrane ◽  
Cell Layer ◽  
Water Flux ◽  
The Other ◽  
Uropathogenic Bacteria ◽  
Urinary Space

The uroepithelium sits at the interface between the urinary space and underlying tissues, where it forms a high-resistance barrier to ion, solute, and water flux, as well as pathogens. However, the uroepithelium is not simply a passive barrier; it can modulate the composition of the urine, and it functions as an integral part of a sensory web in which it receives, amplifies, and transmits information about its external milieu to the underlying nervous and muscular systems. This review examines our understanding of uroepithelial regeneration and how specializations of the outermost umbrella cell layer, including tight junctions, surface uroplakins, and dynamic apical membrane exocytosis/endocytosis, contribute to barrier function and how they are co-opted by uropathogenic bacteria to infect the uroepithelium. Furthermore, we discuss the presence and possible functions of aquaporins, urea transporters, and multiple ion channels in the uroepithelium. Finally, we describe potential mechanisms by which the uroepithelium can transmit information about the urinary space to the other tissues in the bladder proper.

Comparison of Position Control With and Without Friction on a Foot Interface

2019 ◽  
Author(s):  
Brandon Rudolph ◽  
Ryder C. Winck
Keyword(s):  
Position Control ◽  
Path Following ◽  
The Other ◽  
Reaching Task ◽  
Performance Differences ◽  
Control Interface ◽  
Significant Performance

Abstract A foot interface may one day control a third arm to assist the hands with a difficult task, but the interface needs to be easy to use. Developing a good foot interface is challenging because of the need to provide support for the leg, allow the user to disengage with the interface without causing unwanted motion, and make it easy for the user to hold a set position. The addition of friction in the interface can enable the device to meet these goals without negatively affecting performance. Although teleoperation is a well explored area of research, relatively little research has been done that examines the effects of friction on the control interface. This paper presents an experiment in which two foot control interfaces are compared. One device uses friction and the other has no added friction, so there is little resistance to motion in any direction. The experiment uses a reaching task and a path-following task to compare the interfaces. The only statistically significant performance differences were that the friction interface reduced the time needed to stop at a target and reduced excess movement when stopping at a target. Also, subjects indicated a preference for the friction interface. The results show that friction can be added to a foot interface to support the device and user and provide some positive gains in performance.

Effects of Organic Solvent Treated on the Performance and Structure of Polysulfone Tubular Ultrafiltration Membrane

2012 ◽  
Vol 164 ◽  
pp. 203-206 ◽  
Author(s):  
En Hua Liu ◽  
He Ying Xu ◽  
Xu Chen Zhao
Keyword(s):  
Organic Solvent ◽  
Organic Solvents ◽  
Water Flux ◽  
Ultrafiltration Membrane ◽  
The Other ◽  
Egg Protein ◽  
Other Hand

The paper studied the effect of different kinds of organic solvents treated polysulfone tubular ultrafiltration membrane on its performances and structure. The results show that the surface of membrane treaded with n-hexane are smoother and less hydrophily, the content of carbon element increased at the same time. On the other hand, the water flux of membrane treated with alkane decrease, but the rejections to MgSO4 and egg protein increase. While the surface of membrane treated with ethanol are rougher and more hydrophily, the contents of carbon and oxygen increase too. The water flux of membrane treated with alcohols increase obviously, but the rejection to egg protein decrease slightly.

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