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Sample records for membrane encapsulated soil layers

  1. PDGF-metronidazole-encapsulated nanofibrous functional layers on collagen membrane promote alveolar ridge regeneration

    Directory of Open Access Journals (Sweden)

    Ho MH

    2017-08-01

    Full Text Available Ming-Hua Ho,1 Hao-Chieh Chang,2,3 Yu-Chia Chang,3 Jeiannete Claudia,1 Tzu-Chiao Lin,2 Po-Chun Chang2,3 1Department of Chemical Engineering, College of Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan; 2Graduate Institute of Clinical Dentistry, School of Dentistry, National Taiwan University, Taipei, Taiwan; 3Department of Dentistry, National Taiwan University Hospital, Taipei, Taiwan Abstract: This study aimed to develop a functionally graded membrane (FGM to prevent infection and promote tissue regeneration. Poly(L-lactide-co-D,L-lactide encapsulating platelet-derived growth factor (PDLLA-PDGF or metronidazole (PDLLA-MTZ was electrospun to form a nanofibrous layer on the inner or outer surface of a clinically available collagen membrane, respectively. The membrane was characterized for the morphology, molecule release profile, in vitro and in vivo biocompatibility, and preclinical efficiency for alveolar ridge regeneration. The PDLLA-MTZ and PDLLA-PDGF nanofibers were 800–900 nm in diameter, and the thicknesses of the functional layers were 20–30 µm, with sustained molecule release over 28 days. All of the membranes tested were compatible with cell survival in vitro and showed good tissue integration with minimal fibrous capsule formation or inflammation. Cell proliferation was especially prominent on the PDLLA-PDGF layer in vivo. On the alveolar ridge, all FGMs reduced wound dehiscence compared with the control collagen membrane, and the FGM with PDLLA-PDGF promoted osteogenesis significantly. In conclusion, the FGMs with PDLLA-PDGF and PDLLA-MTZ showed high biocompatibility and facilitated wound healing compared with conventional membrane, and the FGM with PDLLA-PDGF enhanced alveolar ridge regeneration in vivo. The design represents a beneficial modification, which may be easily adapted for future clinical use. Keywords: tissue engineering, platelet-derived growth factor, metronidazole, alveolar process

  2. Performance evaluation soil samples utilizing encapsulation technology

    Science.gov (United States)

    Dahlgran, James R.

    1999-01-01

    Performance evaluation soil samples and method of their preparation using encapsulation technology to encapsulate analytes which are introduced into a soil matrix for analysis and evaluation by analytical laboratories. Target analytes are mixed in an appropriate solvent at predetermined concentrations. The mixture is emulsified in a solution of polymeric film forming material. The emulsified solution is polymerized to form microcapsules. The microcapsules are recovered, quantitated and introduced into a soil matrix in a predetermined ratio to form soil samples with the desired analyte concentration.

  3. Layered plasma polymer composite membranes

    Science.gov (United States)

    Babcock, Walter C.

    1994-01-01

    Layered plasma polymer composite fluid separation membranes are disclosed, which comprise alternating selective and permeable layers for a total of at least 2n layers, where n is .gtoreq.2 and is the number of selective layers.

  4. Encapsulation layer design and scalability in encapsulated vertical 3D RRAM

    International Nuclear Information System (INIS)

    Yu, Muxi; Fang, Yichen; Wang, Zongwei; Chen, Gong; Pan, Yue; Yang, Xue; Yin, Minghui; Yang, Yuchao; Li, Ming; Cai, Yimao; Huang, Ru

    2016-01-01

    Here we propose a novel encapsulated vertical 3D RRAM structure with each resistive switching cell encapsulated by dielectric layers, contributing to both the reliability improvement of individual cells and thermal disturbance reduction of adjacent cells due to the effective suppression of unwanted oxygen vacancy diffusion. In contrast to the traditional vertical 3D RRAM, encapsulated bar-electrodes are adopted in the proposed structure substituting the previous plane-electrodes, thus encapsulated resistive switching cells can be naturally formed by simply oxidizing the tip of the metal bar-electrodes. In this work, TaO x -based 3D RRAM devices with SiO 2 and Si 3 N 4 as encapsulation layers are demonstrated, both showing significant advantages over traditional unencapsulated vertical 3D RRAM. Furthermore, it was found thermal conductivity and oxygen blocking ability are two key parameters of the encapsulation layer design influencing the scalability of vertical 3D RRAM. Experimental and simulation data show that oxygen blocking ability is more critical for encapsulation layers in the relatively large scale, while thermal conductivity becomes dominant as the stacking layers scale to the sub-10 nm regime. Finally, based on the notable impacts of the encapsulation layer on 3D RRAM scaling, an encapsulation material with both excellent oxygen blocking ability and high thermal conductivity such as AlN is suggested to be highly desirable to maximize the advantages of the proposed encapsulated structure. The findings in this work could pave the way for reliable ultrahigh-density storage applications in the big data era. (paper)

  5. Effect of layer-by-layer polyelectrolyte method on encapsulation of vanillin.

    Science.gov (United States)

    Noshad, Mohammad; Mohebbi, Mohebbat; Shahidi, Fakhri; Koocheki, Arash

    2015-11-01

    The objective of this work was to microencapsulate vanillin by multilayer emulsion followed by spray drying, aiming to protect it and control its release. An electrostatic layer-by-layer deposition method was used to create the multilayered interfacial membranes around microcapsules with different compositions: (i) one-layer (soy protein isolate); (ii) two-layer (soy protein isolate - OSA starch); (iii) three-layer (soy protein isolate - OSA starch - Chitosan). The morphology of the microcapsules was analyzed by scanning electronic microscopy. The hygroscopicity, solubility, particle size, encapsulation efficiency, Fourier transform infrared spectroscopy and release into water (37°C and 80°C) were also examined. FTIR confirmed the interaction between the wall materials. All microcapsules were not very water-soluble or hygroscopic while three-layer microcapsules compared to one and two layer microcapsules have lower moisture content and predominantly shriveled surfaces. The results indicated it was possible to encapsulate vanillin with the techniques employed and that these protected the vanillin even at 80°C. The reduced solubility and low release rates indicated the enormous potential of the vehicle developed in controlling the release of the vanillin into the food and pharmaceuticals. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Layer-by-layer cell membrane assembly

    Science.gov (United States)

    Matosevic, Sandro; Paegel, Brian M.

    2013-11-01

    Eukaryotic subcellular membrane systems, such as the nuclear envelope or endoplasmic reticulum, present a rich array of architecturally and compositionally complex supramolecular targets that are as yet inaccessible. Here we describe layer-by-layer phospholipid membrane assembly on microfluidic droplets, a route to structures with defined compositional asymmetry and lamellarity. Starting with phospholipid-stabilized water-in-oil droplets trapped in a static droplet array, lipid monolayer deposition proceeds as oil/water-phase boundaries pass over the droplets. Unilamellar vesicles assembled layer-by-layer support functional insertion both of purified and of in situ expressed membrane proteins. Synthesis and chemical probing of asymmetric unilamellar and double-bilayer vesicles demonstrate the programmability of both membrane lamellarity and lipid-leaflet composition during assembly. The immobilized vesicle arrays are a pragmatic experimental platform for biophysical studies of membranes and their associated proteins, particularly complexes that assemble and function in multilamellar contexts in vivo.

  7. Hydrogels for in situ encapsulation of biomimetic membrane arrays

    DEFF Research Database (Denmark)

    Ibragimova, Sania; Jensen, Karin Bagger Stibius; Szewczykowski, Piotr Przemyslaw

    2012-01-01

    to chemically initiated hydrogels; however, for all hydrogels the permeability was several-fold higher than the water permeability of conventional reverse osmosis (RO) membranes. Lifetimes of freestanding BLM arrays in gel precursor solutions were short compared to arrays formed in buffer. However, polymerizing......Hydrogels are hydrophilic, porous polymer networks that can absorb up to thousands of times their own weight in water. They have many potential applications, one of which is the encapsulation of freestanding black lipid membranes (BLMs) for novel separation technologies or biosensor applications....... We investigated gels for in situ encapsulation of multiple BLMs formed across apertures in a hydrophobic ethylene tetrafluoroethylene (ETFE) support. The encapsulation gels consisted of networks of poly(ethylene glycol)-dimethacrylate or poly(ethylene glycol)-diacrylate polymerized using either...

  8. Encapsulation methods and dielectric layers for organic electrical devices

    Science.gov (United States)

    Blum, Yigal D; Chu, William Siu-Keung; MacQueen, David Brent; Shi, Yijan

    2013-07-02

    The disclosure provides methods and materials suitable for use as encapsulation barriers and dielectric layers in electronic devices. In one embodiment, for example, there is provided an electroluminescent device or other electronic device with a dielectric layer comprising alternating layers of a silicon-containing bonding material and a ceramic material. The methods provide, for example, electronic devices with increased stability and shelf-life. The invention is useful, for example, in the field of microelectronic devices.

  9. Lipid Membrane Encapsulation of a 3D DNA Nano Octahedron.

    Science.gov (United States)

    Perrault, Steven D; Shih, William M

    2017-01-01

    Structural DNA nanotechnology methods such as DNA origami allow for the synthesis of highly precise nanometer-scale materials (Rothemund, Nature 440:297-302, 2006; Douglas et al., Nature 459:414-418, 2009). These offer compelling advantages for biomedical applications. Such materials can suffer from structural instability in biological environments due to denaturation and nuclease digestion (Hahn et al., ACS Nano 2014; Perrault and Shih, ACS Nano 8:5132-5140, 2014). Encapsulation of DNA nanostructures in a lipid membrane compartmentalizes them from their environment and prevents denaturation and nuclease digestion (Perrault and Shih, ACS Nano 8:5132-5140, 2014). Here, we describe the encapsulation of a 50 nm DNA nanostructure having the geometry of a wireframe octahedron in a phospholipid membrane containing poly-(ethylene glycol), resulting in biocompatible DNA nanostructures.

  10. Air encapsulation. I. Measurement in a field soil

    International Nuclear Information System (INIS)

    Fayer, M.J.; Hillel, D.

    1986-01-01

    Encapsulated air is an important component of shallow water table fluctuations. Their objective was to measure the quantity and persistence of encapsulated air in a field setting. Using sprinkling rates of either 3.5 x 10 -6 or 3.8 x 10 -5 m s -1 , they brought the water table in a field soil from a depth of 1.5 m to the surface on several occasions. Moisture contents during and after sprinkling were monitored with a neutron probe. Twice following sprinkling, the water table was maintained at the surface for more than 20 d, during which time they continued to monitor moisture contents. With the water table at the surface, differences between the porosity and the measured moisture content were attributed to encapsulated air. Encapsulated air contents ranged from 1.1 to 6.3% of the bulk soil volume, depending on the rate of sprinkling, soil depth, and initial soil moisture content. During ponding, encapsulated air persisted at the 0.3-m depth for up to 28 d. The results indicate that encapsulated air is measurable in a field situation and that its quantity and persistence should be considered in analyzing the results of similar field experiments. 16 references

  11. The Use of encapsulation techniques as an alternative to employment of soil contaminated by petroleum products in base and sub-base of pavement layers

    OpenAIRE

    Francisco das Chagas Isael Teixeira Cavalcante

    2013-01-01

    The petrochemical industry or petroleum deserves special attention because, in practically all stages (drilling, refining, storage and distribution), residues that harm the environment and is a challenge to those responsible for their management are generated. Among the various wastes generated by the oil industry, are the Soils Contaminated by Petroleum Products (SCPD). In Cearà state, the generation of this type of waste is coming from a refinery that is located in Fortaleza city. During ma...

  12. Encapsulation of albumin in self-assembled layer-by-layer microcapsules: comparison of co-precipitation and adsorption techniques.

    Science.gov (United States)

    Labala, Suman; Mandapalli, Praveen Kumar; Bhatnagar, Shubhmita; Venuganti, Venkata Vamsi Krishna

    2015-01-01

    The objective of this study is to prepare and characterize polymeric self-assembled layer-by-layer microcapsules (LbL-MC) to deliver a model protein, bovine serum albumin (BSA). The aim is to compare the BSA encapsulation in LbL-MC using co-precipitation and adsorption methods. In co-precipitation method, BSA was co-precipitated with growing calcium carbonate particles to form a core template. Later, poly(styrene sulfonate) and poly(allylamine hydrochloride) were sequentially adsorbed onto the CaCO3 templates. In adsorption method, preformed LbL-MC were incubated with BSA and encapsulation efficiency is optimized for pH and salt concentration. Free and BSA-encapsulated LbL-MC were characterized using Zetasizer, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy and differential scanning calorimeter. Later, in vitro release studies were performed using dialysis membrane method at pH 4, 7.4 and 9. Results from Zetasizer and SEM showed free LbL-MC with an average size and zeta-potential of 2.0 ± 0.6 μm and 8.1 ± 1.9 mV, respectively. Zeta-potential of BSA-loaded LbL-MC was (-)7.4 ± 0.7 mV and (-)5.7 ± 1.0 mV for co-precipitation and adsorption methods, respectively. In adsorption method, BSA encapsulation in LbL-MC was found to be greater at pH 6.0 and 0.2 M NaCl. Co-precipitation method provided four-fold greater encapsulation efficiency (%) of BSA in LbL-MC compared with adsorption method. At pH 4, the BSA release from LbL-MC was extended up to 120 h. Polyacrylamide gel electrophoresis showed that BSA encapsulated in LBL-MC through co-precipitation is stable toward trypsin treatment. In conclusion, co-precipitation method provided greater encapsulation of BSA in LbL-MC. Furthermore, LbL-MC can be developed as carriers for pH-controlled protein delivery.

  13. Long term investigations of carbon nanotube transistors encapsulated by atomic-layer-deposited Al2O3 for sensor applications

    International Nuclear Information System (INIS)

    Helbling, T; Hierold, C; Roman, C; Durrer, L; Mattmann, M; Bright, V M

    2009-01-01

    Single-walled carbon nanotube field-effect transistors (CNFETs) are promising functional structures in future micro- or nanoelectronic systems and sensor applications. Research on the fundamental device concepts includes the investigation of the conditions for stable long term CNFET operation. CNFET operation in ambient air leads to on-state current degradation and fluctuating signals due to the well-known sensitivity of the electronic properties of the CNT to many environmental condition changes. It is the goal of device and sensor research to understand various kinds of sensor-environment interactions and to overcome the environmental sensitivity. Here, we show that the encapsulation of CNFETs by a thermal atomic-layer-deposited (ALD) aluminium oxide (Al 2 O 3 ) layer of approximately 100 nm leads to stable device operation for 260 days and reduces their sensitivity to the environment. The characteristics of CNFETs prior to and after Al 2 O 3 encapsulation are comparatively investigated. It is found that encapsulation improves the stability of the CNFET characteristics with respect to the gate threshold voltage, hysteresis width and the on-state current, while 1/f noise is lowered by up to a factor of 7. Finally, CNFETs embedded in a dielectric membrane are employed as pressure sensors to demonstrate sensor operation of CNFETs encapsulated by ALD as piezoresistive transducers.

  14. Ceramic nanostructure materials, membranes and composite layers

    NARCIS (Netherlands)

    Burggraaf, A.J.; Keizer, Klaas; van Hassel, B.A.

    1989-01-01

    Synthesis methods to obtain nanoscale materials will be briefly discussed with a focus on sol-gel methods. Three types of nanoscale composites (powders, membranes and ion implanted layers) will be discussed and exemplified with recent original research results. Ceramic membranes with a thickness of

  15. Layer-by-layer polyelectrolyte-polyester hybrid microcapsules for encapsulation and delivery of hydrophobic drugs.

    Science.gov (United States)

    Luo, Rongcong; Venkatraman, Subbu S; Neu, Björn

    2013-07-08

    A two-step process is developed to form layer-by-layer (LbL) polyelectrolyte microcapsules, which are able to encapsulate and deliver hydrophobic drugs. Spherical porous calcium carbonate (CaCO3) microparticles were used as templates and coated with a poly(lactic acid-co-glycolic acid) (PLGA) layer containing hydrophobic compounds via an in situ precipitation gelling process. PLGA layers that precipitated from N-methyl-2-pyrrolidone (NMP) had a lower loading and smoother surface than those precipitated from acetone. The difference may be due to different viscosities and solvent exchange dynamics. In the second step, the successful coating of multilayer polyelectrolytes poly(allylamine hydrochloride) (PAH) and poly(styrene sulfonate) (PSS) onto the PLGA coated CaCO3 microparticles was confirmed with AFM and ζ-potential studies. The release of a model hydrophobic drug, ibuprofen, from these hybrid microcapsules with different numbers of PAH/PSS layers was investigated. It was found that the release of ibuprofen decreases with increasing layer numbers demonstrating the possibility to control the release of ibuprofen with these novel hybrid microcapsules. Besides loading of hydrophobic drugs, the interior of these microcapsules can also be loaded with hydrophilic compounds and functional nanoparticles as demonstrated by loading with Fe3O4 nanoparticles, forming magnetically responsive dual drug releasing carriers.

  16. Novel synthesis of highly durable and active Pt catalyst encapsulated in nitrogen containing carbon for polymer electrolyte membrane fuel cell

    Science.gov (United States)

    Lee, Hyunjoon; Sung, Yung-Eun; Choi, Insoo; Lim, Taeho; Kwon, Oh Joong

    2017-09-01

    Novel synthesis of a Pt catalyst encapsulated in a N-containing carbon layer for use in a polymer electrolyte membrane fuel cell is described in this study. A Pt-aniline complex, formed by mixing Pt precursor and aniline monomer, was used as the source of Pt, C, and N. Heat treatment of the Pt-aniline complex with carbon black yielded 5 nm Pt nanoparticles encapsulated by a N-containing carbon layer originating from aniline carbonization. The synthesized Pt catalyst exhibited higher mass specific activity to oxygen reduction reaction than that shown by conventional Pt/C catalyst because pyridinic N with graphitic carbon in the carbon layer provided active sites for oxygen reduction reaction in addition to those provided by Pt. In single cell testing, initial performance of the synthesized catalyst was limited because the thick catalyst layer increased resistance related to mass transfer. However, it was observed that the carbon layer successfully prevented Pt nanoparticles from growing via agglomeration and Ostwald ripening under fuel cell operation, thereby improving durability. Furthermore, a mass specific performance of the synthesized catalyst higher than that of a conventional Pt/C catalyst was achieved by modifying the synthesized catalyst's layer thickness.

  17. Effect of piroxicam on lipid membranes: Drug encapsulation and gastric toxicity aspects.

    Science.gov (United States)

    Wilkosz, Natalia; Rissanen, Sami; Cyza, Małgorzata; Szybka, Renata; Nowakowska, Maria; Bunker, Alex; Róg, Tomasz; Kepczynski, Mariusz

    2017-03-30

    Uptake of piroxicam, a non-steroidal anti-inflammatory drug, from the intestines after oral intake is limited due to its low solubility and its wide use is associated with several side effects related to the gastrointestinal tract. In this study, all-atom molecular dynamics (MD) simulations and fluorescent spectroscopy were employed to investigate the interaction of piroxicam in neutral, zwitterionic, and cationic forms with lipid bilayers composed of phosphatidylcholine, cholesterol, and PEGylated lipids. Our study was aimed to assess the potential for encapsulation of piroxicam in liposomal carriers and to shed more light on the process of gastrointestinal tract injury by the drug. Through both the MD simulations and laser scanning confocal microscopy, we have demonstrated that all forms of piroxicam can associate with the lipid bilayers and locate close to the water-membrane interface. Conventional liposomes used in drug delivery are usually stabilized by the addition of cholesterol and have their bloodstream lifetime extended through the inclusion of PEGylated lipids in the formulation to create a protective polymer corona. For this reason, we tested the effect of these two modifications on the behavior of piroxicam in the membrane. When the bilayer was PEGylated, piroxicam localize to the PEG layer and within the lipid headgroup region. This suggests that PEGylated liposomes are capable of carrying a larger quantity of piroxicam than the conventional ones. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Encapsulation of Phase Change Materials Using Layer-by-Layer Assembled Polyelectrolytes

    Directory of Open Access Journals (Sweden)

    Qiangying Yi

    2015-01-01

    Full Text Available Phase change materials absorb the thermal energy when changing their phases (e.g., solid-to-liquid at constant temperatures to achieve the latent heat storage. The major drawbacks such as limited thermal conductivity and leakage prevent the PCMs from wide application in desired areas. In this work, an environmentally friendly and low cost approach, layer-by-layer (LbL assembly technique, was applied to build up ultrathin shells to encapsulate the PCMs and therefore to regulate their changes in volume when the phase change occurs. Generally, the oppositely charged strong polyelectrolytes Poly(diallyldimethylammonium chloride (PDADMAC and Poly(4-styrenesulfonic acid sodium salt (PSS were employed to fabricate multilayer shells on emulsified octadecane droplets using either bovine serum albumin (BSA or sodium dodecyl sulfate (SDS as surfactant. Specifically, using BSA as the surfactant, polyelectrolyte encapsulated octadecane spheres in size of ∼500 nm were obtained, with good shell integrity, high octadecane content (91.3% by mass, and good thermal stability after cycles of thermal treatments.

  19. Layer-by-layer assembled multilayers using catalase-encapsulated gold nanoparticles

    International Nuclear Information System (INIS)

    Kim, Sungwoo; Park, Jeongju; Cho, Jinhan

    2010-01-01

    We introduce a novel and versatile approach for the preparation of multilayers, based on catalase-encapsulated gold nanoparticles (CAT-Au NP ), allowing electrostatic charge reversal and structural transformation through pH adjustment. CAT-Au NP , which are synthesized directly from CAT stabilizer, can be electrostatically assembled with anionic and cationic PEs as a result of the charge reversal of the catalase stabilizers through pH control. In particular, at pH 5.2, near the pI of catalase, dispersed CAT-Au NP are structurally transformed into colloidal or network CAT-Au NP nanocomposites. Furthermore, we demonstrate that the layer-by-layer assembled multilayers composed of PEs and CAT-Au NP induce an effective electron transfer between CAT and the electrode as well as a high loading of CAT and Au NP , and resultantly exhibit a highly catalytic activity toward H 2 O 2 .

  20. Silicon nanopore membrane (SNM) for islet encapsulation and immunoisolation under convective transport

    Science.gov (United States)

    Song, Shang; Faleo, Gaetano; Yeung, Raymond; Kant, Rishi; Posselt, Andrew M.; Desai, Tejal A.; Tang, Qizhi; Roy, Shuvo

    2016-03-01

    Problems associated with islet transplantation for Type 1 Diabetes (T1D) such as shortage of donor cells, use of immunosuppressive drugs remain as major challenges. Immune isolation using encapsulation may circumvent the use of immunosuppressants and prolong the longevity of transplanted islets. The encapsulating membrane must block the passage of host’s immune components while providing sufficient exchange of glucose, insulin and other small molecules. We report the development and characterization of a new generation of semipermeable ultrafiltration membrane, the silicon nanopore membrane (SNM), designed with approximately 7 nm-wide slit-pores to provide middle molecule selectivity by limiting passage of pro-inflammatory cytokines. Moreover, the use of convective transport with a pressure differential across the SNM overcomes the mass transfer limitations associated with diffusion through nanometer-scale pores. The SNM exhibited a hydraulic permeability of 130 ml/hr/m2/mmHg, which is more than 3 fold greater than existing polymer membranes. Analysis of sieving coefficients revealed 80% reduction in cytokines passage through SNM under convective transport. SNM protected encapsulated islets from infiltrating cytokines and retained islet viability over 6 hours and remained responsive to changes in glucose levels unlike non-encapsulated controls. Together, these data demonstrate the novel membrane exhibiting unprecedented hydraulic permeability and immune-protection for islet transplantation therapy.

  1. Controlling the Growth of Staphylococcus epidermidis by Layer-By-Layer Encapsulation.

    Science.gov (United States)

    Jonas, Alain M; Glinel, Karine; Behrens, Adam; Anselmo, Aaron C; Langer, Robert S; Jaklenec, Ana

    2018-05-16

    Commensal skin bacteria such as Staphylococcus epidermidis are currently being considered as possible components in skin-care and skin-health products. However, considering the potentially adverse effects of commensal skin bacteria if left free to proliferate, it is crucial to develop methodologies that are capable of maintaining bacteria viability while controlling their proliferation. Here, we encapsulate S. epidermidis in shells of increasing thickness using layer-by-layer assembly, with either a pair of synthetic polyelectrolytes or a pair of oppositely charged polysaccharides. We study the viability of the cells and their delay of growth depending on the composition of the shell, its thickness, the charge of the last deposited layer, and the degree of aggregation of the bacteria which is varied using different coating procedures-among which is a new scalable process that easily leads to large amounts of nonaggregated bacteria. We demonstrate that the growth of bacteria is not controlled by the mechanical properties of the shell but by the bacteriostatic effect of the polyelectrolyte complex, which depends on the shell thickness and charge of its outmost layer, and involves the diffusion of unpaired amine sites through the shell. The lag times of growth are sufficient to prevent proliferation for daily topical applications.

  2. Hypersonic Poration of Membranes : From Triggered Release and Encapsulation to Drug Delivery

    NARCIS (Netherlands)

    Lu, Yao

    2018-01-01

    In this thesis, hypersonic poration is introduced as a new physical method to precisely control membrane permeability for the applications of controlled release and encapsulation, and enhanced drug delivery. Bulk acoustic wave (BAW) resonators of gigahertz (GHz) frequency have been fabricated using

  3. Inorganic Substrates and Encapsulation Layers for Transient Electronics

    Science.gov (United States)

    2014-07-01

    as substrates and encapsulating materials, with demonstrated options that range from films of silk fibroin, polycaprolactone (PCL), polyglycolic...PDMS) (Dow Corning , USA) coated on glass slides to facilitate processing. SiO2 (~1 μm) was deposited by PECVD on these foils for electrical...with laminating the foils Fe, Mo, W, and Zn, ~10 μm thick (Goodfellow, USA) on glass slides coated with PDMS (Dow Corning Co., USA) as temporary

  4. Amplified CPEs enhancement of chorioamnion membrane mass transport by encapsulation in nano-sized PLGA particles.

    Science.gov (United States)

    Azagury, Aharon; Amar-Lewis, Eliz; Appel, Reut; Hallak, Mordechai; Kost, Joseph

    2017-08-01

    Chemical penetration enhancers (CPEs) have long been used for mass transport enhancement across membranes. Many CPEs are used in a solution or gel and could be a solvent. The use of CPEs is mainly limited due to their toxicity/irritation levels. This study presents the evaluation of encapsulated CPEs in nano-sized polymeric particles on the chorioamnion (CA) membrane mass transport. CPEs' mass encapsulated in nanoparticles was decreased by 10,000-fold. Interestingly, this approach resulted in a 6-fold increase in mass transport across the CA. This approach may also be used with other CPEs' base applications necessitating lower CPE concentration. Applying Ultrasound (US) has shown to increase the release rate of and also the mass transport across the CA membrane. It is proposed that encapsulated CPEs penetrate into the CA membrane thus prolonging their exposure, possibly extending their penetration into the CA membrane, while insonation also deepens their penetration into the CA membrane. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Block copolymer/homopolymer dual-layer hollow fiber membranes

    KAUST Repository

    Hilke, Roland; Neelakanda, Pradeep; Behzad, Ali Reza; Nunes, Suzana Pereira; Peinemann, Klaus-Viktor

    2014-01-01

    We manufactured the first time block copolymer dual-layer hollow fiber membranes and dual layer flat sheet membranes manufactured by double solution casting and phase inversion in water. The support porous layer was based on polystyrene

  6. Role of an encapsulating layer for reducing resistance drift in phase change random access memory

    Directory of Open Access Journals (Sweden)

    Bo Jin

    2014-12-01

    Full Text Available Phase change random access memory (PCRAM devices exhibit a steady increase in resistance in the amorphous phase upon aging and this resistance drift phenomenon directly affects the device reliability. A stress relaxation model is used here to study the effect of a device encapsulating layer material in addressing the resistance drift phenomenon in PCRAM. The resistance drift can be increased or decreased depending on the biaxial moduli of the phase change material (YPCM and the encapsulating layer material (YELM according to the stress relationship between them in the drift regime. The proposed model suggests that the resistance drift can be effectively reduced by selecting a proper material as an encapsulating layer. Moreover, our model explains that reducing the size of the phase change material (PCM while fully reset and reducing the amorphous/crystalline ratio in PCM help to improve the resistance drift, and thus opens an avenue for highly reliable multilevel PCRAM applications.

  7. Layer-by-layer assembled multilayers using catalase-encapsulated gold nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sungwoo; Park, Jeongju [School of Advanced Materials Engineering, Kookmin University, Jeongneung-dong, Seongbuk-gu, Seoul 136-702 (Korea, Republic of); Cho, Jinhan, E-mail: jinhan71@korea.ac.kr [Department of Chemical and Biological Engineering, Korea University, Anam-dong, Seongbuk-gu, Seoul 136-701 (Korea, Republic of)

    2010-09-17

    We introduce a novel and versatile approach for the preparation of multilayers, based on catalase-encapsulated gold nanoparticles (CAT-Au{sub NP}), allowing electrostatic charge reversal and structural transformation through pH adjustment. CAT-Au{sub NP}, which are synthesized directly from CAT stabilizer, can be electrostatically assembled with anionic and cationic PEs as a result of the charge reversal of the catalase stabilizers through pH control. In particular, at pH 5.2, near the pI of catalase, dispersed CAT-Au{sub NP} are structurally transformed into colloidal or network CAT-Au{sub NP} nanocomposites. Furthermore, we demonstrate that the layer-by-layer assembled multilayers composed of PEs and CAT-Au{sub NP} induce an effective electron transfer between CAT and the electrode as well as a high loading of CAT and Au{sub NP}, and resultantly exhibit a highly catalytic activity toward H{sub 2}O{sub 2}.

  8. Influence of charge on encapsulation and release behavior of small molecules in self-assembled layer-by-layer microcapsules.

    Science.gov (United States)

    Mandapalli, Praveen K; Labala, Suman; Vanamala, Deekshith; Koranglekar, Manali P; Sakimalla, Lakshmi A; Venuganti, Venkata Vamsi K

    2014-12-01

    The objective of this study is to investigate the influence of charge of model small molecules on their encapsulation and release behavior in layer-by-layer microcapsules (LbL-MC). Poly(styrene sulfonate) and poly(ethylene imine) were sequentially adsorbed on calcium carbonate sacrificial templates to prepare LbL-MC. Model molecules with varying charge, anionic - ascorbic acid, cationic - imatinib mesylate (IM) and neutral - 5-fluorouracil were encapsulated in LbL-MC. Free and encapsulated LbL-MC were characterized using zetasizer, FTIR spectroscope and differential scanning calorimeter. The influence of IM-loaded LbL-MC on cell viability was studied in B16F10 murine melanoma cells. Furthermore, biodistribution of IM-loaded LbL-MC with and without PEGylation was studied in BALB/c mice. Results showed spherical LbL-MC of 3.0 ± 0.4 μm diameter. Encapsulation efficiency of LbL-MC increased linearly (R(2 )= 0.89-0.99) with the increase in solute concentration. Increase in pH from 2 to 6 increased the encapsulation of charged molecules in LbL-MC. Charged molecules showed greater encapsulation efficiency in LbL-MC compared with neutral molecule. In vitro release kinetics showed Fickian and non-Fickian diffusion of small molecules, depending on the nature of molecular interactions with LbL-MC. At 50 μM concentration, free IM showed significantly (p < 0.05) more cytotoxicity compared with IM-loaded LbL-MC. Biodistribution studies showed that PEGylation of LbL-MC decreased the liver and spleen uptake of IM-encapsulated LbL-MC. In conclusion, LbL-MC can be developed as a potential carrier for small molecules depending on their physical and chemical properties.

  9. Graphitic Layer Encapsulated Iron Based Non‐precious Catalysts for the Oxygen Reduction Reaction

    DEFF Research Database (Denmark)

    Zhong, Lijie

    consisting of uniform metallic nanoparticles encapsulated in graphitic layers. The thesis work is conducted aiming at three major objectives: further optimization of the pyrolysis to achieve improved performance of catalysts, investigation of the complex Fe-containing components, and exploration...... of the nitrogen functionalities. Two anions in the electrolyte are used to probe the iron containing active sites towards the ORR, cyanide (CN-) in alkaline and thiocyanate (SCN-) in acidic medium, which seem supporting the above conclusions. These findings provide new insights to the encapsulation structure...

  10. Amperometric glucose biosensor based on layer-by-layer films of microperoxidase-11 and liposome-encapsulated glucose oxidase.

    Science.gov (United States)

    Graça, J S; de Oliveira, R F; de Moraes, M L; Ferreira, M

    2014-04-01

    An important step in several bioanalytical applications is the immobilization of biomolecules. Accordingly, this procedure must be carefully chosen to preserve their biological structure and fully explore their properties. For this purpose, we combined the versatility of the layer-by-layer (LbL) method for the immobilization of biomolecules with the protective behavior of liposome-encapsulated systems to fabricate a novel amperometric glucose biosensor. To obtain the biosensing unit, an LbL film of the H2O2 catalyst polypeptide microperoxidase-11 (MP-11) was assembled onto an indium-tin oxide (ITO) electrode followed by the deposition of a liposome-encapsulated glucose oxidase (GOx) layer. The biosensor response toward glucose detection showed a sensitivity of 0.91±0.09 (μA/cm2)/mM and a limit of detection (LOD) of 8.6±1.1 μM, demonstrating an improved performance compared to similar biosensors with a single phospholipid-liposome or even containing a non-encapsulated GOx layer. Finally, glucose detection was also performed in a zero-lactose milk sample to demonstrate the potential of the biosensor for food analysis. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Micro-fabricated Liquid Encapsulated Energy Harvester with Polymer Barrier Layer as Liquid Electret Interface

    International Nuclear Information System (INIS)

    Bu, L; Xu, H Y; Xu, B J; Song, L

    2014-01-01

    This paper addresses the electret discharge issue for liquid based electret energy harvesters. An interface structure of PDMS/PTFE polymer barrier layer between liquid and electrets is introduced, achieving 75% charge retain rate over 100h, compared with 0% without the proposed layer over 100h. Further, the PDMS/PTFE layer is introduced into liquid encapsulated energy harvester (LEEH) and is compatible with micro-fabrication process. The retain rate of device voltage is about 47%∼65% over 100h. At 100h after corona charging, the device generates maximally 3.7V, 0.55μW @1Hz rotation

  12. Gel layer formation on membranes in Membrane Bioreactors

    NARCIS (Netherlands)

    Van den Brink, P.F.H.

    2014-01-01

    The widespread application of membrane bioreactors (MBRs) for municipal wastewater treatment is hampered by membrane fouling. Fouling increases energy demand, reduces process performance and creates the need for more frequent (chemical) membrane cleaning or replacement. Membrane fouling in MBRs is

  13. Block copolymer/homopolymer dual-layer hollow fiber membranes

    KAUST Repository

    Hilke, Roland

    2014-12-01

    We manufactured the first time block copolymer dual-layer hollow fiber membranes and dual layer flat sheet membranes manufactured by double solution casting and phase inversion in water. The support porous layer was based on polystyrene and the selective layer with isopores was formed by micelle assembly of polystyrene-. b-poly-4-vinyl pyridine. The dual layers had an excellent interfacial adhesion and pore interconnectivity. The dual membranes showed pH response behavior like single layer block copolymer membranes with a low flux for pH values less than 3, a fast increase between pH4 and pH6 and a constant high flux level for pH values above 7. The dry/wet spinning process was optimized to produce dual layer hollow fiber membranes with polystyrene internal support layer and a shell block copolymer selective layer.

  14. Water transport and desalination through double-layer graphyne membranes.

    Science.gov (United States)

    Akhavan, Mojdeh; Schofield, Jeremy; Jalili, Seifollah

    2018-05-16

    Non-equilibrium molecular dynamics simulations of water-salt solutions driven through single and double-layer graphyne membranes by a pressure difference created by rigid pistons are carried out to determine the relative performance of the membranes as filters in a reverse osmosis desalination process. It is found that the flow rate of water through a graphyne-4 membrane is twice that of a graphyne-3 membrane for both single and double-layer membranes. Although the addition of a second layer to a single-layer membrane reduces the membrane permeability, the double-layer graphyne membranes are still two or three orders of magnitude more permeable than commercial reverse osmosis membranes. The minimum reduction in flow rate for double-layer membranes occurs at a layer spacing of 0.35 nm with an AA stacking configuration, while at a spacing of 0.6 nm the flow rate is close to zero due to a high free energy barrier for permeation. This is caused by the difference in the environments on either side of the membrane sheets and the formation of a compact two-dimensional layer of water molecules in the interlayer space which slows down water permeation. The distribution of residence times of water molecules in the interlayer region suggests that at the critical layer spacing of 0.6 nm, a cross-over occurs in the mechanism of water flow from the collective movement of hydrogen-bonded water sheets to the permeation of individual water molecules. All membranes are demonstrated to have a high salt rejection fraction and the double-layered graphyne-4 membranes can further increase the salt rejection by trapping ions that have passed through the first membrane from the feed solution in the interlayer space.

  15. Efficient, air-stable colloidal quantum dot solar cells encapsulated using atomic layer deposition of a nanolaminate barrier

    KAUST Repository

    Ip, Alexander H.; Labelle, André J.; Sargent, Edward H.

    2013-01-01

    Atomic layer deposition was used to encapsulate colloidal quantum dot solar cells. A nanolaminate layer consisting of alternating alumina and zirconia films provided a robust gas permeation barrier which prevented device performance degradation over a period of multiple weeks. Unencapsulated cells stored in ambient and nitrogen environments demonstrated significant performance losses over the same period. The encapsulated cell also exhibited stable performance under constant simulated solar illumination without filtration of harsh ultraviolet photons. This monolithically integrated thin film encapsulation method is promising for roll-to-roll processed high efficiency nanocrystal solar cells. © 2013 AIP Publishing LLC.

  16. Efficient, air-stable colloidal quantum dot solar cells encapsulated using atomic layer deposition of a nanolaminate barrier

    KAUST Repository

    Ip, Alexander H.

    2013-12-23

    Atomic layer deposition was used to encapsulate colloidal quantum dot solar cells. A nanolaminate layer consisting of alternating alumina and zirconia films provided a robust gas permeation barrier which prevented device performance degradation over a period of multiple weeks. Unencapsulated cells stored in ambient and nitrogen environments demonstrated significant performance losses over the same period. The encapsulated cell also exhibited stable performance under constant simulated solar illumination without filtration of harsh ultraviolet photons. This monolithically integrated thin film encapsulation method is promising for roll-to-roll processed high efficiency nanocrystal solar cells. © 2013 AIP Publishing LLC.

  17. A membrane film sensor with encapsulated fluorescent dyes towards express freshness monitoring of packaged food.

    Science.gov (United States)

    Kiryukhin, Maxim V; Lau, Hooi Hong; Goh, Seok Hong; Teh, Cathleen; Korzh, Vladimir; Sadovoy, Anton

    2018-05-15

    A new Membrane Film Sensor (MFS) has been developed to measure pH of fluids. MFS comprises a polyelectrolyte multilayer film with uniformly distributed compartments (microchambers) where a fluorescent sensing dye is encapsulated. Fabricated film is sealed onto a polyethylene film for a future use. MFS was applied to report changes in golden pomfret fillet upon its storage at 5 °C. MFS pH readings were correlated to bacteriological analysis of fish samples. A hike in pH of fish juices happens after 10 days of storage signaling bacterial spoilage of fish. The design of developed MFS allows easy integration with transparent packaging materials for future development of "SMART" packaging sensing food freshness. Copyright © 2018 Elsevier B.V. All rights reserved.

  18. Environmental Decontamination of a Chemical Warfare Simulant Utilizing a Membrane Vesicle-Encapsulated Phosphotriesterase.

    Science.gov (United States)

    Alves, Nathan J; Moore, Martin; Johnson, Brandy J; Dean, Scott N; Turner, Kendrick B; Medintz, Igor L; Walper, Scott A

    2018-05-09

    While technologies for the remediation of chemical contaminants continue to emerge, growing interest in green technologies has led researchers to explore natural catalytic mechanisms derived from microbial species. One such method, enzymatic degradation, offers an alternative to harsh chemical catalysts and resins. Recombinant enzymes, however, are often too labile or show limited activity when challenged with nonideal environmental conditions that may vary in salinity, pH, or other physical properties. Here, we demonstrate how phosphotriesterase encapsulated in a bacterial outer membrane vesicle can be used to degrade the organophosphate chemical warfare agent (CWA) simulant paraoxon in environmental water samples. We also carried out remediation assays on solid surfaces, including glass, painted metal, and fabric, that were selected as representative materials, which could potentially be contaminated with a CWA.

  19. Capacitance-voltage analysis of electrical properties for WSe2 field effect transistors with high-k encapsulation layer

    Science.gov (United States)

    Ko, Seung-Pil; Shin, Jong Mok; Jang, Ho Kyun; You, Min Youl; Jin, Jun-Eon; Choi, Miri; Cho, Jiung; Kim, Gyu-Tae

    2018-02-01

    Doping effects in devices based on two-dimensional (2D) materials have been widely studied. However, detailed analysis and the mechanism of the doping effect caused by encapsulation layers has not been sufficiently explored. In this work, we present experimental studies on the n-doping effect in WSe2 field effect transistors (FETs) with a high-k encapsulation layer (Al2O3) grown by atomic layer deposition. In addition, we demonstrate the mechanism and origin of the doping effect. After encapsulation of the Al2O3 layer, the threshold voltage of the WSe2 FET negatively shifted with the increase of the on-current. The capacitance-voltage measurements of the metal insulator semiconductor (MIS) structure proved the presence of the positive fixed charges within the Al2O3 layer. The flat-band voltage of the MIS structure of Au/Al2O3/SiO2/Si was shifted toward the negative direction on account of the positive fixed charges in the Al2O3 layer. Our results clearly revealed that the fixed charges in the Al2O3 encapsulation layer modulated the Fermi energy level via the field effect. Moreover, these results possibly provide fundamental ideas and guidelines to design 2D materials FETs with high-performance and reliability.

  20. Thin-film encapsulation of organic electronic devices based on vacuum evaporated lithium fluoride as protective buffer layer

    Science.gov (United States)

    Peng, Yingquan; Ding, Sihan; Wen, Zhanwei; Xu, Sunan; Lv, Wenli; Xu, Ziqiang; Yang, Yuhuan; Wang, Ying; Wei, Yi; Tang, Ying

    2017-03-01

    Encapsulation is indispensable for organic thin-film electronic devices to ensure reliable operation and long-term stability. For thin-film encapsulating organic electronic devices, insulating polymers and inorganic metal oxides thin films are widely used. However, spin-coating of insulating polymers directly on organic electronic devices may destroy or introduce unwanted impurities in the underlying organic active layers. And also, sputtering of inorganic metal oxides may damage the underlying organic semiconductors. Here, we demonstrated that by utilizing vacuum evaporated lithium fluoride (LiF) as protective buffer layer, spin-coated insulating polymer polyvinyl alcohol (PVA), and sputtered inorganic material Er2O3, can be successfully applied for thin film encapsulation of copper phthalocyanine (CuPc)-based organic diodes. By encapsulating with LiF/PVA/LiF trilayer and LiF/Er2O3 bilayer films, the device lifetime improvements of 10 and 15 times can be achieved. These methods should be applicable for thin-film encapsulation of all kinds of organic electronic devices. Moisture-induced hole trapping, and Al top electrode oxidation are suggest to be the origins of current decay for the LiF/PVA/LiF trilayer and LiF/Er2O3 bilayer films encapsulated devices, respectively.

  1. New type of chitosan/2-hydroxypropyl-β-cyclodextrin composite membrane for gallic acid encapsulation and controlled release.

    Science.gov (United States)

    Paun, Gabriela; Neagu, Elena; Tache, Andreia; Radu, G L

    2014-01-01

    A new type of chitosan/2-hydroxypropyl-β-cyclodextrin composite membrane have been developed for the encapsulation and controlled release of gallic acid. The morphology of the composite membrane was investigated by infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM), whereas swelling gallic acid and release properties were investigated by UV-visible spectroscopy. The release behavior with pH changes was also explored. The composite membrane based on chitosan/2-hydroxypropyl-β-cyclodextrin with gallic acid included showed improved antioxidant capacities compared to plain chitosan membrane. The information obtained in this study will facilitate the design and preparation of composite membrane based on chitosan and could open a wide range of applications, particularly its use as an antioxidant in food, food packaging, biomedical (biodegradable soft porous scaffolds for enhance the surrounding tissue regeneration), pharmaceutical and cosmetics industries.

  2. Self-Healing Textile: Enzyme Encapsulated Layer-by-Layer Structural Proteins.

    Science.gov (United States)

    Gaddes, David; Jung, Huihun; Pena-Francesch, Abdon; Dion, Genevieve; Tadigadapa, Srinivas; Dressick, Walter J; Demirel, Melik C

    2016-08-10

    Self-healing materials, which enable an autonomous repair response to damage, are highly desirable for the long-term reliability of woven or nonwoven textiles. Polyelectrolyte layer-by-layer (LbL) films are of considerable interest as self-healing coatings due to the mobility of the components comprising the film. In this work mechanically stable self-healing films were fabricated through construction of a polyelectrolyte LbL film containing squid ring teeth (SRT) proteins. SRTs are structural proteins with unique self-healing properties and high elastic modulus in both dry and wet conditions (>2 GPa) due to their semicrystalline architecture. We demonstrate LbL construction of multilayers containing native and recombinant SRT proteins capable of self-healing defects. Additionally, we show these films are capable of utilizing functional biomolecules by incorporating an enzyme into the SRT multilayer. Urease was chosen as a model enzyme of interest to test its activity via fluorescence assay. Successful construction of the SRT films demonstrates the use of mechanically stable self-healing coatings, which can incorporate biomolecules for more complex protective functionalities for advanced functional fabrics.

  3. New method for fabrication of loaded micro- and nanocontainers: emulsion encapsulation by polyelectrolyte layer-by-layer deposition on the liquid core.

    Science.gov (United States)

    Grigoriev, D O; Bukreeva, T; Möhwald, H; Shchukin, D G

    2008-02-05

    A novel approach to the emulsion encapsulation was developed by combining the advantages of direct encapsulation of a liquid colloidal core with the accuracy and multifunctionality of layer-by-layer polyelectrolyte deposition. Experimental data obtained for the model oil-in-water emulsion confirm unambiguously the alternating PE assembly in the capsule shell as well as the maintenance of the liquid colloidal core. Two different mechanisms of capsule destruction upon interaction with the solid substrate were observed and qualitatively explained. The proposed method can be easily generalized to the preparation of oil-filled capsules in various oil/water/polyelectrolyte systems important in the field of pharmacy, medicine, and food industry.

  4. A Study on Organic-Metal Halide Perovskite Film Morphology, Interfacial Layers, Tandem Applications, and Encapsulation

    Science.gov (United States)

    Fisher, Dallas A.

    decreased drastically due to poor band alignment. Fe2O3 appears to be better suited to a narrower band gap material than methylammonium lead iodide perovskite. Finally, encapsulation of perovskite devices with epoxy coatings is explored as a method to improve long-term stability. Perovskites are sensitive to a variety of conditions, but most importantly water and polar molecules. Encapsulants act as a moisture/oxygen barrier, but also prevent outgassing of the organic components. Three epoxies were tested in high heat and high humidity conditions. Important factors in the curing process were uncovered such as the sensitivity of UV-epoxies to amine functional groups found in common p-type dopants and perovskite layers. Moisture ingress was the failure point for high-humidity/heat devices which was confirmed through conversion to yellow lead iodide. A revised device fabrication method is proposed to reduce moisture ingress for future experiments.

  5. POROUS MEMBRANE TEMPLATED SYNTHESIS OF POLYMER PILLARED LAYER

    Institute of Scientific and Technical Information of China (English)

    Zhong-wei Niu; Dan Li; Zhen-zhong Yang

    2003-01-01

    The anodic porous alumina membranes with a definite pore diameter and aspect ratio were used as templates to synthesize polymer pillared layer structures. The pillared polymer was produced in the template membrane pores, and the layer on the template surfaces. Rigid cured epoxy resin, polystyrene and soft hydrogel were chosen to confirm the methodology. The pillars were in the form of either tubes or fibers, which were controlled by the alumina membrane pore surface wettability. The structural features were confirmed by scanning electron microscopy results.

  6. Effects of europium polyoxometalate encapsulated in silica nanoparticles (nanocarriers) in soil invertebrates

    Energy Technology Data Exchange (ETDEWEB)

    Bicho, Rita C., E-mail: ritabicho@ua.pt; Soares, Amadeu M.V.M. [Universidade de Aveiro, Departamento de Biologia & CESAM (Portugal); Nogueira, Helena I.S. [Universidade de Aveiro, Departamento de Química & CICECO (Portugal); Amorim, Mónica J.B. [Universidade de Aveiro, Departamento de Biologia & CESAM (Portugal)

    2016-12-15

    Polyoxometalates (POMs) are metal oxo clusters that have been investigated for several applications in material sciences, catalysis, and biomedicine; these gained increasing interest in the field of nanotechnology as nanocarriers for drug delivery. Associated to the increasing applications, there is the need for information regarding the effects on the environment of these compounds, which is completely absent in the literature. In the present study, the effects of europium polyoxometalates encapsulated into silica nanoparticles (Eu-POM/SiO{sub 2} NPs) were assessed on the soil representative Enchytraeus crypticus. The individual materials were also assessed (Eu-POMs and SiO{sub 2} NPs). Toxicity was evaluated in various test media with increasing complexity: water, soil/water extracts, and soil. Toxicity was only observed for Eu-POM/SiO{sub 2} NPs and in the presence of soil components. Despite the fact that effects were observed for concentrations higher than current predicted environmental concentration (PEC), attention should be given to the growing use of these compounds. The present study shows the importance of assessing the effects in soil media, also compared to water. Moreover, results of “no effect” are critically needed and often unpublished. The present study can contribute to the improvement of the OECD guidelines for safety of manufactured nanomaterials on environmental toxicity in the soil compartment providing an improved test alternative.

  7. Effects of europium polyoxometalate encapsulated in silica nanoparticles (nanocarriers) in soil invertebrates

    International Nuclear Information System (INIS)

    Bicho, Rita C.; Soares, Amadeu M.V.M.; Nogueira, Helena I.S.; Amorim, Mónica J.B.

    2016-01-01

    Polyoxometalates (POMs) are metal oxo clusters that have been investigated for several applications in material sciences, catalysis, and biomedicine; these gained increasing interest in the field of nanotechnology as nanocarriers for drug delivery. Associated to the increasing applications, there is the need for information regarding the effects on the environment of these compounds, which is completely absent in the literature. In the present study, the effects of europium polyoxometalates encapsulated into silica nanoparticles (Eu-POM/SiO 2 NPs) were assessed on the soil representative Enchytraeus crypticus. The individual materials were also assessed (Eu-POMs and SiO 2 NPs). Toxicity was evaluated in various test media with increasing complexity: water, soil/water extracts, and soil. Toxicity was only observed for Eu-POM/SiO 2 NPs and in the presence of soil components. Despite the fact that effects were observed for concentrations higher than current predicted environmental concentration (PEC), attention should be given to the growing use of these compounds. The present study shows the importance of assessing the effects in soil media, also compared to water. Moreover, results of “no effect” are critically needed and often unpublished. The present study can contribute to the improvement of the OECD guidelines for safety of manufactured nanomaterials on environmental toxicity in the soil compartment providing an improved test alternative.

  8. Hierarchical Composite Membranes with Robust Omniphobic Surface Using Layer-By-Layer Assembly Technique

    KAUST Repository

    Woo, Yun Chul

    2018-01-17

    In this study, composite membranes were fabricated via layer-by-layer (LBL) assembly of negatively-charged silica aerogel (SiA) and 1H, 1H, 2H, 2H – Perfluorodecyltriethoxysilane (FTCS) on a polyvinylidene fluoride phase inversion membrane, and interconnecting them with positively-charged poly(diallyldimethylammonium chloride) (PDDA) via electrostatic interaction. The results showed that the PDDA-SiA-FTCS coated membrane had significantly enhanced the membrane structure and properties. New trifluoromethyl and tetrafluoroethylene bonds appeared at the surface of the coated membrane, which led to lower surface free energy of the composite membrane. Additionally, the LBL membrane showed increased surface roughness. The improved structure and property gave the LBL membrane an omniphobic property, as indicated by its good wetting resistance. The membrane performed a stable air gap membrane distillation (AGMD) flux of 11.22 L/m2h with very high salt rejection using reverse osmosis brine from coal seam gas produced water as feed with the addition of up to 0.5 mM SDS solution. This performance was much better compared to those of the neat membrane. The present study suggests that the enhanced membrane properties with good omniphobicity via LBL assembly make the porous membranes suitable for long-term AGMD operation with stable permeation flux when treating challenging saline wastewater containing low surface tension organic contaminants.

  9. Ion Transport through Diffusion Layer Controlled by Charge Mosaic Membrane

    Directory of Open Access Journals (Sweden)

    Akira Yamauchi

    2012-01-01

    Full Text Available The kinetic transport behaviors in near interface of the membranes were studied using commercial anion and cation exchange membrane and charge mosaic membrane. Current-voltage curve gave the limiting current density that indicates the ceiling of conventional flux. From chronopotentiometry above the limiting current density, the transition time was estimated. The thickness of boundary layer was derived with conjunction with the conventional limiting current density and the transition time from steady state flux. On the other hand, the charge mosaic membrane was introduced in order to examine the ion transport on the membrane surface in detail. The concentration profile was discussed by the kinetic transport number with regard to the water dissociation (splitting on the membrane surface.

  10. Effect of layer-by-layer coatings and localization of antioxidant on oxidative stability of a model encapsulated bioactive compound in oil-in-water emulsions.

    Science.gov (United States)

    Pan, Yuanjie; Nitin, N

    2015-11-01

    Oxidation of encapsulated bioactives in emulsions is one of the key challenges that limit shelf-life of many emulsion containing products. This study seeks to quantify the role of layer-by-layer coatings and localization of antioxidant molecules at the emulsion interface in influencing oxidation of the encapsulated bioactives. Oxidative barrier properties of the emulsions were simulated by measuring the rate of reaction of peroxyl radicals generated in the aqueous phase with the encapsulated radical sensitive dye in the lipid core of the emulsions. The results of peroxyl radical permeation were compared to the stability of encapsulated retinol (model bioactive) in emulsions. To evaluate the role of layer-by-layer coatings in influencing oxidative barrier properties, radical permeation rates and retinol stability were evaluated in emulsion formulations of SDS emulsion and SDS emulsion with one or two layers of polymers (ϵ-polylysine and dextran sulfate) coated at the interface. To localize antioxidant molecules to the interface, gallic acid (GA) was chemically conjugated with ϵ-polylysine and subsequently deposited on SDS emulsion based on electrostatic interactions. Emulsion formulations with localized GA molecules at the interface were compared with SDS emulsion with GA molecules in the bulk aqueous phase. The results of this study demonstrate the advantage of localization of antioxidant at the interface and the limited impact of short chain polymer coatings at the interface of emulsions in reducing permeation of radicals and oxidation of a model encapsulated bioactive in oil-in-water emulsions. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Improving gas sensor properties of encapsulated ZnO nanorods for ethanol detection using ZnO:Cr layer as an encapsulated layer

    Directory of Open Access Journals (Sweden)

    S. Safa

    2017-11-01

    Full Text Available In this study, encapsulated ZnO nanorods with different amount of chromium (Cr dopant (0-4.5 at.% were prepared with hydrothermal method, and their sensitivities as gas sensors against ethanol vapor were investigated. Morphologies of samples were explored by field emission scanning electron microscope (FESEM which showed that encapsulation process increased the diameter of ZnO nanorods. Existence of Cr in ZnO nanorods structures was confirmed by Energy-dispersive X-ray spectroscopy (EDX. Based on X-ray diffraction (XRD analysis, the ZnO:Cr nanorods had wurtzite crystal structure, and adding Cr did not alter the crystal structure of ZnO. Electrical measurements revealed that current levels of samples were decreased by adding Cr, while the current level of the sample with 4.5 at.% was increased. This reduction could be attributed to the presence of Cr3+ ions, which led to decrease of charge carriers. Besides, due to the catalytic properties of Cr and its lower ionization energy than Zn, it was observed that Cr dopant improved the detection sensitivity of samples, and decreased the optimum operating temperature of samples. Among all samples, the most sensitivity (14 was obtained based on the sample with 1.5 at.% of Cr for 500 ppm ethanol vapor at the optimum temperature (250 . In fact, by encapsulating the samples, they became rougher, so the appropriate places to absorb and decompose of gas molecules are increased.

  12. On the resistances of membrane, diffusion boundary layer and double layer in ion exchange membrane transport

    NARCIS (Netherlands)

    Długołȩcki, P.; Ogonowski, P.; Metz, S.J.; Saakes, M.; Nijmeijer, K.; Wessling, M.

    2010-01-01

    Membrane resistances are often measured under direct current conditions using a standard 0.5 M NaCl characterization solution, although several electro-membrane processes (e.g. reverse electrodialysis, electrodialysis, fuel cells, microbial fuel cells and membrane capacitive deionization) operate in

  13. Fluid-membrane tethers: minimal surfaces and elastic boundary layers.

    Science.gov (United States)

    Powers, Thomas R; Huber, Greg; Goldstein, Raymond E

    2002-04-01

    Thin cylindrical tethers are common lipid bilayer membrane structures, arising in situations ranging from micromanipulation experiments on artificial vesicles to the dynamic structure of the Golgi apparatus. We study the shape and formation of a tether in terms of the classical soap-film problem, which is applied to the case of a membrane disk under tension subject to a point force. A tether forms from the elastic boundary layer near the point of application of the force, for sufficiently large displacement. Analytic results for various aspects of the membrane shape are given.

  14. Effect of Plasma Membrane Semipermeability in Making the Membrane Electric Double Layer Capacitances Significant.

    Science.gov (United States)

    Sinha, Shayandev; Sachar, Harnoor Singh; Das, Siddhartha

    2018-01-30

    Electric double layers (or EDLs) formed at the membrane-electrolyte interface (MEI) and membrane-cytosol interface (MCI) of a charged lipid bilayer plasma membrane develop finitely large capacitances. However, these EDL capacitances are often much larger than the intrinsic capacitance of the membrane, and all of these capacitances are in series. Consequently, the effect of these EDL capacitances in dictating the overall membrane-EDL effective capacitance C eff becomes negligible. In this paper, we challenge this conventional notion pertaining to the membrane-EDL capacitances. We demonstrate that, on the basis of the system parameters, the EDL capacitance for both the permeable and semipermeable membranes can be small enough to influence C eff . For the semipermeable membranes, however, this lowering of the EDL capacitance can be much larger, ensuring a reduction of C eff by more than 20-25%. Furthermore, for the semipermeable membranes, the reduction in C eff is witnessed over a much larger range of system parameters. We attribute such an occurrence to the highly nonintuitive electrostatic potential distribution associated with the recently discovered phenomena of charge-inversion-like electrostatics and the attainment of a positive zeta potential at the MCI for charged semipermeable membranes. We anticipate that our findings will impact the quantification and the identification of a large number of biophysical phenomena that are probed by measuring the plasma membrane capacitance.

  15. Graphene layer encapsulated metal nanoparticles as a new type of non-precious metal catalysts for oxygen reduction

    DEFF Research Database (Denmark)

    Hu, Yang; Zhong, Lijie; Jensen, Jens Oluf

    2016-01-01

    Cheap and efficient non-precious metal catalysts for oxygen reduction have been a focus of research in the field of low-temperature fuel cells. This review is devoted to a brief summary of the recent work on a new type of catalysts, i.e., the graphene layer encapsulated metal nanoparticles....... The discussion is focused on the synthesis, structure, mechanism, performance, and further research....

  16. Plasma-assisted atomic layer deposition of Al(2)O(3) and parylene C bi-layer encapsulation for chronic implantable electronics.

    Science.gov (United States)

    Xie, Xianzong; Rieth, Loren; Merugu, Srinivas; Tathireddy, Prashant; Solzbacher, Florian

    2012-08-27

    Encapsulation of biomedical implants with complex three dimensional geometries is one of the greatest challenges achieving long-term functionality and stability. This report presents an encapsulation scheme that combines Al(2)O(3) by atomic layer deposition with parylene C for implantable electronic systems. The Al(2)O(3)-parylene C bi-layer was used to encapsulate interdigitated electrodes, which were tested invitro by soak testing in phosphate buffered saline solution at body temperature (37 °C) and elevated temperatures (57 °C and 67 °C) for accelerated lifetime testing up to 5 months. Leakage current and electrochemical impedance spectroscopy were measured for evaluating the integrity and insulation performance of the coating. Leakage current was stably about 15 pA at 5 V dc, and impedance was constantly about 3.5 MΩ at 1 kHz by using electrochemical impedance spectroscopy for samples under 67 °C about 5 months (approximately equivalent to 40 months at 37 °C). Alumina and parylene coating lasted at least 3 times longer than parylene coated samples tested at 80 °C. The excellent insulation performance of the encapsulation shows its potential usefulness for chronic implants.

  17. Apparatus for plasma surface treating and preparation of membrane layers

    NARCIS (Netherlands)

    1990-01-01

    An apparatus suitable for plasma surface treating (e.g., forming a membrane layer on a substrate surface) comprises a plasma generation section which is operable at least at substantially atmospheric pressure and is in communication via at least one plasma inlet (e.g., a nozzle) with an enclosed

  18. Method for plasma surface treating and preparation of membrane layers

    NARCIS (Netherlands)

    1992-01-01

    The invention relates to an apparatus suitable for plasma surface treating (e.g. forming a membrane layer on a substrate) which comprises a plasma generation section (2) which is in communication via at least one plasma inlet means (4) (e.g. a nozzle) with an enclosed plasma treating section (3)

  19. Membrane filtration device for studying compression of fouling layers in membrane bioreactors.

    Directory of Open Access Journals (Sweden)

    Mads Koustrup Jørgensen

    Full Text Available A filtration devise was developed to assess compressibility of fouling layers in membrane bioreactors. The system consists of a flat sheet membrane with air scouring operated at constant transmembrane pressure to assess the influence of pressure on resistance of fouling layers. By fitting a mathematical model, three model parameters were obtained; a back transport parameter describing the kinetics of fouling layer formation, a specific fouling layer resistance, and a compressibility parameter. This stands out from other on-site filterability tests as model parameters to simulate filtration performance are obtained together with a characterization of compressibility. Tests on membrane bioreactor sludge showed high reproducibility. The methodology's ability to assess compressibility was tested by filtrations of sludges from membrane bioreactors and conventional activated sludge wastewater treatment plants from three different sites. These proved that membrane bioreactor sludge showed higher compressibility than conventional activated sludge. In addition, detailed information on the underlying mechanisms of the difference in fouling propensity were obtained, as conventional activated sludge showed slower fouling formation, lower specific resistance and lower compressibility of fouling layers, which is explained by a higher degree of flocculation.

  20. Polymeric membranes modulate human keratinocyte differentiation in specific epidermal layers.

    Science.gov (United States)

    Salerno, Simona; Morelli, Sabrina; Giordano, Francesca; Gordano, Amalia; Bartolo, Loredana De

    2016-10-01

    In vitro models of human bioengineered skin substitutes are an alternative to animal experimentation for testing the effects and toxicity of drugs, cosmetics and pollutants. For the first time specific and distinct human epidermal strata were engineered by using membranes and keratinocytes. To this purpose, biodegradable membranes of chitosan (CHT), polycaprolactone (PCL) and a polymeric blend of CHT-PCL were prepared by phase-inversion technique and characterized in order to evaluate their morphological, physico-chemical and mechanical properties. The capability of membranes to modulate keratinocyte differentiation inducing specific interactions in epidermal membrane systems was investigated. The overall results demonstrated that the membrane properties strongly influence the cell morpho-functional behaviour of human keratinocytes, modulating their terminal differentiation, with the creation of specific epidermal strata or a fully proliferative epidermal multilayer system. In particular, human keratinocytes adhered on CHT and CHT-PCL membranes, forming the structure of the epidermal top layers, such as the corneum and granulosum strata, characterized by withdrawal or reduction from the cell cycle and cell proliferation. On the PCL membrane, keratinocytes developed an epidermal basal lamina, with high proliferating cells that stratified and migrated over time to form a complete differentiating epidermal multilayer system. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Preparation and characterization of composite membrane via layer by layer assembly for desalination

    Energy Technology Data Exchange (ETDEWEB)

    Wasim, Maria, E-mail: maria-be24@hotmail.co.uk; Sabir, Aneela; Shafiq, Muhammad; Islam, Atif; Jamil, Tahir

    2017-02-28

    Highlights: • Cellulose acetate based polymer composite membranes were formed via layer by layer assembly for nanofiltration. • Modified membranes shown improved MgSO{sub 4} salt rejection property up to 98.9%. • Surface roughness and antibacterial property of fabricated membrane were successfully studied. - Abstract: Cellulose acetate (CA) incorporated with sepiolite and Polyvinylpyrrolidone (PVP) multilayer composite on Polysulfone (PSf) substrate have been prepared by layer by layer (LbL) assembly method. Fourier TransformInfrared Spectroscopy (FTIR) results verified the hydrogen bonding among the components of composite membrane. Atomic force microscopy (AFM), scanning electron microscope (SEM) was carried out for the determination and elucidation of roughness and morphology of the fabricated membranes on PSf substrate. The AFM and SEM results showed the increased surface roughness with the porous and spongy structure. The performance results verified that the successful incorporation of sepiolite in membranes showed maximum MgSO{sub 4} rejection (98.9%) and flux of 38.7 L/m{sup 2} h. Whereas, in case of NaCl the rejection is 98.3% and flux is 34.9L/m{sup 2} h. The modification was evidenced to be effective in increasing the surface hydrophilicity that led to increase in surface roughness. The chlorine resistivity is improved by dropping the active sites for chlorine attack and protecting the underlying PSf substrate.

  2. Layer-by-Layer Assembly for Preparation of High-Performance Forward Osmosis Membrane

    Science.gov (United States)

    Yang, Libin; Zhang, Jinglong; Song, Peng; Wang, Zhan

    2018-01-01

    Forward osmosis (FO) membrane with high separation performance is needed to promote its practical applications. Herein, layer-by-layer (LbL) approach was used to prepare a thin and highly cross-linked polyamide layer on a polyacrylonitrile substrate surface to prepare a thin-film composite forward osmosis (TFC-FO) membrane with enhanced FO performance. The effects of monomer concentrations and assembly cycles on the performance of the TFC-FO membranes were systematically investigated. Under the optimal preparation condition, TFC-FO membrane achieved the best performance, exhibiting the water flux of 14.4/6.9 LMH and reverse salt flux of 7.7/3.8 gMH under the pressure retarded osmosis/forward osmosis (PRO/FO) mode using 1M NaCl as the draw against a DI-water feed, and a rejection of 96.1% for 2000 mg/L NaCl aqueous solution. The result indicated that layer-by-layer method was a potential method to regulate the structure and performance of the TFC-FO membrane.

  3. Membrane interactions and antimicrobial effects of layered double hydroxide nanoparticles

    DEFF Research Database (Denmark)

    Malekkhaiat Häffner, S; Nyström, L; Nordström, R

    2017-01-01

    Membrane interactions are critical for the successful use of inorganic nanoparticles as antimicrobial agents and as carriers of, or co-actives with, antimicrobial peptides (AMPs). In order to contribute to an increased understanding of these, we here investigate effects of particle size (42-208 nm...... into size-dependent synergistic effects with the antimicrobial peptide LL-37. Due to strong interactions with anionic lipopolysaccharide and peptidoglycan layers, direct membrane disruption of both Gram-negative and Gram-positive bacteria is suppressed. However, LDH nanoparticles cause size-dependent charge...

  4. Layer by Layer Composite Membranes of Alginate-Chitosan Crosslinked by Glutaraldehyde in Pervaporation Dehydration of Ethanol

    Directory of Open Access Journals (Sweden)

    Nur Rokhati

    2016-08-01

    Full Text Available Hydrophilicity of membrane causing only water can pass through membrane. Pervaporation process using organophilic membrane has been offered as alternative for ethanol dehydration. This paper investigate pervaporation based biopolymer composite membrane from alginate-chitosan using layer by layer method prepared by glutaraldehyde as crosslinking agent and polyethersulfone (PES as supported membrane. Characterization of crosslinked of composite membrane by FTIR helped in identification of sites for interaction between layers of membrane and support layer (PES. The SEM showed a multilayer structure and a distinct interface between the chitosan layer, the sodium alginate layer and the support layer. The coating sequence of membranes had an obvious influence on the pervaporation dehydration performance of membranes. For the dehydration of 95 wt% ethanol-water mixtures, a good performance of PES-chitosan-alginate-chitosan (PES/Chi/Alg/Chi composite membrane was found in the pervaporation dehydration of ethanol. Article History: Received April 12nd , 2016; Received in revised form June 25th , 2016; Accepted July 1st , 2016; Available online How to Cite This Article: Rokhati, N., Istirokhatun, T. and Samsudin, A.M. (2016 Layer by Layer Composite Membranes of Alginate-Chitosan Crosslinked by Glutaraldehyde in Pervaporation Dehydration of Ethanol. Int. Journal of Renewable Energy Development, 5(2, 101-106. http://dx.doi.org/10.14710/ijred.5.2.101-106 

  5. Characteristics of water infiltration in layered water repellent soils

    Science.gov (United States)

    Hydrophobic soil can influence soil water infiltration, but information regarding the impacts of different levels of hydrophobicity within a layered soil profile is limited. An infiltration study was conducted to determine the effects of different levels of hydrophobicity and the position of the hyd...

  6. Ultimate capacity of piles penetrating in weak soil layers

    Directory of Open Access Journals (Sweden)

    Al-Obaidi Ahmed

    2018-01-01

    Full Text Available A pile foundation is one of the most popular forms of deep foundations. They are routinely employed to transfer axial structure loads through the soft soil to stronger bearing strata. Piles generally used to increase the load carrying capacity of the foundation and reduce the settlement of the foundation. On the other hand, many cases in practice where piles pass through different layers of soil that contain weak layers located at different depths and extension, also some time cavities with a different shape, size, and depth are found. In this study, a total of 96 cases is considered and simulated in PLAXIS 2D program aiming to understand the influence of weak soil on the ultimate pile capacity. The piles embedded in the dense sand with a layer of weak soil at different extension and location. The cross section of the geometry used in this study was designed as an axisymmetric model with the 15-node element; the boundary condition recommended at least 5D in the horizontal direction, and (L+5D in the vertical direction where D and L are the diameter and length of pile, respectively. The soil is modeled as Mohr-Coulomb, with five input parameters and the behavior of pile material represented by the linear elastic model. The results of the above cases are compared with the results found in a pile embedded in dense soil without weak layers or cavities. The results indicated that the existence of weak soil layer within the surrounding soil around the pile decreases the ultimate capacity. Furthermore, it has been found that increase in the weak soil width (extension leads to reduction in the ultimate capacity of the pile. This phenomenon is applicable to all depth of weak soil. The influence of weak layer extension on the ultimate capacity is less when it is presentin the upper soil layers.

  7. Dissolution of Monocrystalline Silicon Nanomembranes and Their Use as Encapsulation Layers and Electrical Interfaces in Water-Soluble Electronics.

    Science.gov (United States)

    Lee, Yoon Kyeung; Yu, Ki Jun; Song, Enming; Barati Farimani, Amir; Vitale, Flavia; Xie, Zhaoqian; Yoon, Younghee; Kim, Yerim; Richardson, Andrew; Luan, Haiwen; Wu, Yixin; Xie, Xu; Lucas, Timothy H; Crawford, Kaitlyn; Mei, Yongfeng; Feng, Xue; Huang, Yonggang; Litt, Brian; Aluru, Narayana R; Yin, Lan; Rogers, John A

    2017-12-26

    The chemistry that governs the dissolution of device-grade, monocrystalline silicon nanomembranes into benign end products by hydrolysis serves as the foundation for fully eco/biodegradable classes of high-performance electronics. This paper examines these processes in aqueous solutions with chemical compositions relevant to groundwater and biofluids. The results show that the presence of Si(OH) 4 and proteins in these solutions can slow the rates of dissolution and that ion-specific effects associated with Ca 2+ can significantly increase these rates. This information allows for effective use of silicon nanomembranes not only as active layers in eco/biodegradable electronics but also as water barriers capable of providing perfect encapsulation until their disappearance by dissolution. The time scales for this encapsulation can be controlled by introduction of dopants into the Si and by addition of oxide layers on the exposed surfaces.The former possibility also allows the doped silicon to serve as an electrical interface for measuring biopotentials, as demonstrated in fully bioresorbable platforms for in vivo neural recordings. This collection of findings is important for further engineering development of water-soluble classes of silicon electronics.

  8. Experimental study on the membrane electrode assembly of a proton exchange membrane fuel cell: effects of microporous layer, membrane thickness and gas diffusion layer hydrophobic treatment

    International Nuclear Information System (INIS)

    Ferreira, Rui B.; Falcão, D.S.; Oliveira, V.B.; Pinto, A.M.F.R.

    2017-01-01

    Highlights: • EIS is employed to investigate the MEA design of a PEM fuel cell. • Effects of MPL, membrane thickness and GDL hydrophobic treatment are studied. • MPL increases cell output at low to medium currents but reduces it at high currents. • Better results are obtained when employing a thinner Nafion membrane. • GDL hydrophobic treatment improves the cell performance. - Abstract: In this study, electrochemical impedance spectroscopy (EIS) is employed to analyze the influence of microporous layer (MPL), membrane thickness and gas diffusion layer (GDL) hydrophobic treatment in the performance of a proton exchange membrane (PEM) fuel cell. Results show that adding a MPL increases cell performance at low to medium current densities. Because lower ohmic losses are observed when applying a MPL, such improvement is attributed to a better hydration state of the membrane. The MPL creates a pressure barrier for water produced at the cathode, forcing it to travel to the anode side, therefore increasing the water content in the membrane. However, at high currents, this same phenomenon seems to have intensified liquid water flooding in the anode gas channels, increasing mass transfer losses and reducing the cell performance. Decreasing membrane thickness results into considerably higher performances, due to a decrease in ohmic resistance. Moreover, at low air humidity operation, a rapid recovery from dehydration is observed when a thinner membrane is employed. The GDL hydrophobic treatment significantly improves the cell performance. Untreated GDLs appear to act as water-traps that not only hamper reactants transport to the reactive sites but also impede the proper humidification of the cell. From the different designs tested, the highest maximum power density is obtained from that containing a MPL, a thinner membrane and treated GDLs.

  9. Electrical Resistance and Transport Numbers of Ion-Exchange Membranes Used in Electrodialytic Soil Remediation

    DEFF Research Database (Denmark)

    Hansen, Henrik; Ottosen, Lisbeth M.; Villumsen, Arne

    1999-01-01

    Electrodialytic soil remediation is a recently developed method to decontaminate heavy metal polluted soil using ion-exchange membranes. In this method one side of the ion-exchange membrane is in direct contact with the polluted soil. It is of great importance to know if this contact with the soil...... different electrodialytic soil remediation experiments. The experiments showed that after the use in electrodialytic soil remediation, the ion-exchange membranes had transport numbers in the same magnitude as new membranes. The electrical resistance for six membranes did not differ from that of new...

  10. Synthesis of PbI(2) single-layered inorganic nanotubes encapsulated within carbon nanotubes.

    Science.gov (United States)

    Cabana, Laura; Ballesteros, Belén; Batista, Eudar; Magén, César; Arenal, Raúl; Oró-Solé, Judith; Rurali, Riccardo; Tobias, Gerard

    2014-04-02

    The template assisted growth of single-layered inorganic nanotubes is reported. Single-crystalline lead iodide single-layered nanotubes have been prepared using the inner cavities of carbon nanotubes as hosting templates. The diameter of the resulting inorganic nanotubes is merely dependent on the diameter of the host. This facile method is highly versatile opening up new horizons in the preparation of single-layered nanostructures. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Method for Aluminum Oxide Thin Films Prepared through Low Temperature Atomic Layer Deposition for Encapsulating Organic Electroluminescent Devices

    Directory of Open Access Journals (Sweden)

    Hui-Ying Li

    2015-02-01

    Full Text Available Preparation of dense alumina (Al2O3 thin film through atomic layer deposition (ALD provides a pathway to achieve the encapsulation of organic light emitting devices (OLED. Unlike traditional ALD which is usually executed at higher reaction n temperatures that may affect the performance of OLED, this application discusses the development on preparation of ALD thin film at a low temperature. One concern of ALD is the suppressing effect of ambient temperature on uniformity of thin film. To mitigate this issue, the pumping time in each reaction cycle was increased during the preparation process, which removed reaction byproducts and inhibited the formation of vacancies. As a result, the obtained thin film had both high uniformity and density properties, which provided an excellent encapsulation performance. The results from microstructure morphology analysis, water vapor transmission rate, and lifetime test showed that the difference in uniformity between thin films prepared at low temperatures, with increased pumping time, and high temperatures was small and there was no obvious influence of increased pumping time on light emitting performance. Meanwhile, the permeability for water vapor of the thin film prepared at a low temperature was found to reach as low as 1.5 × 10−4 g/(m2·day under ambient conditions of 25 °C and 60% relative humidity, indicating a potential extension in the lifetime for the OLED.

  12. Relating performance of thin-film composite forward osmosis membranes to support layer formation and structure

    KAUST Repository

    Tiraferri, Alberto; Yip, Ngai Yin; Phillip, William A.; Schiffman, Jessica D.; Elimelech, Menachem

    2011-01-01

    the technology to the point that it is commercially viable. Here, a systematic investigation of the influence of thin-film composite membrane support layer structure on forward osmosis performance is conducted. The membranes consist of a selective polyamide

  13. Spontaneous membrane formation and self-encapsulation of active rods in an inhomogeneous motility field

    NARCIS (Netherlands)

    Grauer, J.; Löwen, H.; Janssen, L.M.C.

    2018-01-01

    We study the collective dynamics of self-propelled rods in an inhomogeneous motility field. At the interface between two regions of constant but different motility, a smectic rod layer is spontaneously created through aligning interactions between the active rods, reminiscent of an artificial,

  14. Application of a mixture of soils to create a stable layer of support on the slope in ponds waterproofed with geo membranes. Application to a specific case in the reservoir Conseller Jose Ramon Garcia Anton in Elche (Alicante)

    International Nuclear Information System (INIS)

    Ferran Gozalvez, F. J.; Ferrer Gisbert, C.; Redon Santafe, M.; Perez Sanchez, M.; Torregrosa Solar, J. S.; Zapata Raboso, F. J.; Sanchez Romero, F. J.

    2014-01-01

    This text present the experience developed in a reservoir in Elche (Alicante). This communication explains the importance of the layer of support to prevent the punching. This phenomenon can occur in a reservoir that has a deficient layer of support. Also, the paper describes the requirements to be met by the support layer to perform its function. (Author)

  15. Soil Plasticity Model for Analysis of Collapse Load on Layers Soil

    Directory of Open Access Journals (Sweden)

    Md Nujid Masyitah

    2016-01-01

    Full Text Available Natural soil consist of soil deposits which is a soil layer overlying a thick stratum of another soil. The bearing capacity of layered soil studies have been conducted using different approach whether theoretical, experimental and combination of both. Numerical method in computer programme has become a powerful tool in solving complex geotechnical problems. Thus in numerical modelling, stress-strain soil behaviour is well predicted, design and interpreted using appropriate soil model. It is also important to identify parameters and soil model involve in prediction real soil problem. The sand layer overlaid clay layer soil is modelled with Mohr-Coulomb and Drucker-Prager criterion. The bearing capacity in loaddisplacement analysis from COMSOL Multiphysics is obtained and presented. In addition the stress distribution and evolution of plastic strain for each thickness ratio below centre of footing are investigated. The results indicate the linear relation on load-displacement which have similar trend for both soil models while stress and plastic strain increase as thickness ratio increase.

  16. Prevention of intra-abdominal adhesion by bi-layer electrospun membrane.

    Science.gov (United States)

    Jiang, Shichao; Wang, Wei; Yan, Hede; Fan, Cunyi

    2013-06-04

    The aim of this study was to compare the anti-adhesion efficacy of a bi-layer electrospun fibrous membrane consisting of hyaluronic acid-loaded poly(ε-caprolactone) (PCL) fibrous membrane as the inner layer and PCL fibrous membrane as the outer layer with a single-layer PCL electrospun fibrous membrane in a rat cecum abrasion model. The rat model utilized a cecal abrasion and abdominal wall insult surgical protocol. The bi-layer and PCL membranes were applied between the cecum and the abdominal wall, respectively. Control animals did not receive any treatment. After postoperative day 14, a visual semiquantitative grading scale was used to grade the extent of adhesion. Histological analysis was performed to reveal the features of adhesion tissues. Bi-layer membrane treated animals showed significantly lower adhesion scores than control animals (p compared with the PCL membrane. Histological analysis of the bi-layer membrane treated rat rarely demonstrated tissue adhesion while that of the PCL membrane treated rat and control rat showed loose and dense adhesion tissues, respectively. Bi-layer membrane can efficiently prevent adhesion formation in abdominal cavity and showed a significantly decreased adhesion tissue formation compared with the control.

  17. 57Fe-Mössbauer spectroscopy and electrochemical activities of graphitic layer encapsulated iron electrocatalysts for the oxygen reduction reaction

    DEFF Research Database (Denmark)

    Zhong, Lijie; Frandsen, Cathrine; Mørup, Steen

    2018-01-01

    Graphitic layer encapsulated iron based nanoparticles (G@FeNPs) have recently been disclosed as an interesting type of highly active electrocatalysts for the oxygen reduction reaction (ORR). However, the complex composition of the metal-containing components and their contributions in catalysis r...

  18. Enhanced optical-to-THz conversion efficiency of photoconductive antenna using dielectric nano-layer encapsulation

    Science.gov (United States)

    Gupta, Abhishek; Rana, Goutam; Bhattacharya, Arkabrata; Singh, Abhishek; Jain, Ravikumar; Bapat, Rudheer D.; Duttagupta, S. P.; Prabhu, S. S.

    2018-05-01

    Photoconductive antennas (PCAs) are among the most conventional devices used for emission as well as detection of terahertz (THz) radiation. However, due to their low optical-to-THz conversion efficiencies, applications of these devices in out-of-laboratory conditions are limited. In this paper, we report several factors of enhancement in THz emission efficiency from conventional PCAs by coating a nano-layer of dielectric (TiO2) on the active area between the electrodes of a semi-insulating GaAs-based device. Extensive experiments were done to show the effect of thicknesses of the TiO2 layer on the THz power enhancement with different applied optical power and bias voltages. Multiphysics simulations were performed to elucidate the underlying physics behind the enhancement of efficiency of the PCA. Additionally, this layer increases the robustness of the electrode gaps of the PCAs with high electrical insulation as well as protect it from external dust particles.

  19. Improved antifouling properties of polymer membranes using a ‘layer-by-layer’ mediated method

    KAUST Repository

    Chen, Lin; Thé rien-Aubin, Hé loï se; Wong, Mavis C. Y.; Hoek, Eric M. V.; Ober, Christopher K.

    2013-01-01

    Polymeric reverse osmosis membranes were modified with antifouling polymer brushes through a 'layer by layer' (LBL) mediated method. Based on pure physical electrostatic interaction, the attachment of LBL films did not alter separation performance

  20. Nanoporous layered silicate AMH-3/cellulose acetate nanocomposite membranes for gas separations

    KAUST Repository

    Kim, Wun-gwi; Lee, Jong Suk; Bucknall, David G.; Koros, William J.; Nair, Sankar

    2013-01-01

    Nanoporous layered silicate/polymer composite membranes are of interest because they can exploit the high aspect ratio of exfoliated selective flakes/layers to enhance molecular sieving and create a highly tortuous transport path for the slower

  1. Membranes having aligned 1-D nanoparticles in a matrix layer for improved fluid separation

    Science.gov (United States)

    Revanur, Ravindra; Lulevich, Valentin; Roh, Il Juhn; Klare, Jennifer E.; Kim, Sangil; Noy, Aleksandr; Bakajin, Olgica

    2015-12-22

    Membranes for fluid separation are disclosed. These membranes have a matrix layer sandwiched between an active layer and a porous support layer. The matrix layer includes 1-D nanoparticles that are vertically aligned in a porous polymer matrix, and which substantially extend through the matrix layer. The active layer provides species-specific transport, while the support layer provides mechanical support. A matrix layer of this type has favorable surface morphology for forming the active layer. Furthermore, the pores that form in the matrix layer tend to be smaller and more evenly distributed as a result of the presence of aligned 1-D nanoparticles. Improved performance of separation membranes of this type is attributed to these effects.

  2. Relating performance of thin-film composite forward osmosis membranes to support layer formation and structure

    KAUST Repository

    Tiraferri, Alberto

    2011-02-01

    Osmotically driven membrane processes have the potential to treat impaired water sources, desalinate sea/brackish waters, and sustainably produce energy. The development of a membrane tailored for these processes is essential to advance the technology to the point that it is commercially viable. Here, a systematic investigation of the influence of thin-film composite membrane support layer structure on forward osmosis performance is conducted. The membranes consist of a selective polyamide active layer formed by interfacial polymerization on top of a polysulfone support layer fabricated by phase separation. By systematically varying the conditions used during the casting of the polysulfone layer, an array of support layers with differing structures was produced. The role that solvent quality, dope polymer concentration, fabric layer wetting, and casting blade gate height play in the support layer structure formation was investigated. Using a 1M NaCl draw solution and a deionized water feed, water fluxes ranging from 4 to 25Lm-2h-1 with consistently high salt rejection (>95.5%) were produced. The relationship between membrane structure and performance was analyzed. This study confirms the hypothesis that the optimal forward osmosis membrane consists of a mixed-structure support layer, where a thin sponge-like layer sits on top of highly porous macrovoids. Both the active layer transport properties and the support layer structural characteristics need to be optimized in order to fabricate a high performance forward osmosis membrane. © 2010 Elsevier B.V.

  3. Increase of rotation angle of soil layers during plow operation

    Science.gov (United States)

    Vasilenko, VV; Afonichev, D. N.; Vasilenko, S. V.; Khakhulin, A. N.

    2018-03-01

    One of the advantages of plowing is the ability of the plow to hide the weed seeds deep into the soil. The depth of the embankment exceeds 10-12 cm, from there the weeds can not rise to the surface of the soil. They perish halfway. But for this, it is necessary to wrap the soil layers at an angle close to 180 °. Modern ploughs can not turn the layers of soil at an angle of more than 135 °, therefore the plow is required to be equipped with additional working elements. The aim of the study is to create an adaptation to the plow to expand the furrow before laying the next soil layer. In a wide furrow, the formation will completely tip, the previous layer will not interfere with it. The device is a set of vertical shields. Each shield is fixed behind the working body of the plow. It is installed with an angle of attack of 20-25 ° to move the previous layer to expand the furrow by 10-12 cm. The model and industrial samples of the plow have shown improved agrotechnical indicators. The average angle of the formation rotation was 177 °, the burial of plant residues in the soil increased from 61 to 99%. The field surface with blocks more than 5 cm decreased from 36.3 to 13.4%, the height of the ridges decreased from 7 to 4 cm. The force of soil pressure on the shield was measured by a strain gage. It is 130-330 N depending on the depth of processing and the speed of movement. The increase in power costs for the four-hull plow was 190-750 W. The coulters on the plow are unnecessary, and this saves energy more than its increase for shields.

  4. Novel Electrospun Dual-Layered Composite Nanofibrous Membrane Endowed with Electricity-Magnetism Bifunctionality at One Layer and Photoluminescence at the Other Layer.

    Science.gov (United States)

    Wang, Zijiao; Ma, Qianli; Dong, Xiangting; Li, Dan; Xi, Xue; Yu, Wensheng; Wang, Jinxian; Liu, Guixia

    2016-10-05

    Dual-layered composite nanofibrous membrane equipped with electrical conduction, magnetism and photoluminescence trifunctionality is constructed via electrospinning. The composite membrane consists of a polyaniline (PANI)/Fe 3 O 4 nanoparticles (NPs)/polyacrylonitrile (PAN) tuned electrical-magnetic bifunctional nanofibrous layer at one side and a Eu(TTA) 3 (TPPO) 2 /polyvinylpyrrolidone (PVP) photoluminescent nanofibrous layer at the other side, and the two layers are tightly combined face-to-face together into the novel dual-layered composite membrane with trifunctionality. The electric conductivity and magnetism of electrical-magnetic bifunctionality can be respectively tunable via modulating the respective PANI and Fe 3 O 4 NPs contents, and the highest electric conductivity approaches the order of 1 × 10 -2 S cm -1 . Predominant red emission at 615 nm can be obviously observed in the photoluminescent layer under 366 nm excitation. Moreover, the luminescent intensity of photoluminescent layer is almost unaffected by the electrical-magnetic bifunctional layer because of the fact that the photoluminescent materials have been successfully isolated from dark-colored PANI and Fe 3 O 4 NPs. The novel dual-layered composite nanofibrous membrane with trifunctionality has potentials in many fields. Furthermore, the design philosophy and fabrication method for the dual-layered multifunctional membrane provide a new and facile strategy toward other membranes with multifunctionality.

  5. Kinematic seismic response of piles in layered soil profile

    International Nuclear Information System (INIS)

    Ahmad, I.; Khan, A.N.

    2006-01-01

    This paper is aimed at highlighting the importance of Kinematic Seismic Response of Piles, a phenomenon often ignored in dynamic analysis. A case study is presented where the end bearing pile is embedded in two layer soil system of highly contrasting stiffnesses; a typical case where kinematic loading plays important role. The pile soil system is modeled as continuous system and as discrete parameter system; both are based on BDWF (Beam on Dynamic Winkler Foundation) formulation. For discrete parameter system, a finite element software SAP2000 is used and the modeling technique of kinematic interaction in finite element software is discussed. For pile soil system modeled as continuous system, a general MATLAB code is developed capable of performing elastic site response analysis in two layer soil system, solving differential equation governing kinematic interaction, and giving as output the maximum ground displacement, maximum pile displacement, rotation, moment and shear distribution along pile length. The paper concludes that kinematic seismic actions must be evaluated particularly at the interface of soil layers of significantly differing soil stiffnesses. (author)

  6. Fabrication of hemispherical liquid encapsulated structures based on droplet molding

    Science.gov (United States)

    Ishizuka, Hiroki; Miki, Norihisa

    2015-12-01

    We have developed and demonstrated a method for forming spherical structures of a thin polydimethylsiloxane (PDMS) membrane encapsulating a liquid. Liquid encapsulation can enhance the performance of microelectromechanical systems (MEMS) devices by providing deformability and improved dielectric properties. Parylene deposition and wafer bonding are applied to encapsulate liquid into a MEMS device. In parylene deposition, a parylene membrane is directly formed onto a liquid droplet. However, since the parylene membrane is stiff, the membrane is fragile. Although wafer bonding can encapsulate liquid between two substrates, the surface of the fabricated structure is normally flat. We propose a new liquid encapsulation method by dispensing liquid droplets. At first, a 20 μl PDMS droplet is dispensed on ethylene glycol. A 70 μl glycerin droplet is dispensed into a PDMS casting solution layer. The droplet forms a layer on heated ethylene glycol. Glycerin and ethylene glycol are chosen for their high boiling points. Additionally, a glycerin droplet is dispensed on the layer and surrounded by a thin PDMS casting solution film. The film is baked for 1 h at 75 °C. As the result, a structure encapsulating a liquid in a flexible PDMS membrane is obtained. We investigate the effects of the volume, surface tension, and guide thickness on the shape of the formed structures. We also evaluated the effect of the structure diameter on miniaturization. The structure can be adapted for various functions by changing the encapsulated liquid. We fabricated a stiffness-tunable structure by dispensing a magnetorheoligical fluid droplet with a stiffness that can be changed by an external magnetic field. We also confirmed that the proposed structure can produce stiffness differences that are distinguishable by humans.

  7. Enhanced performance of proton exchange membrane fuel cell by introducing nitrogen-doped CNTs in both catalyst layer and gas diffusion layer

    CSIR Research Space (South Africa)

    Hou, S

    2017-11-01

    Full Text Available The performance of the proton exchange membrane fuel cell (PEMFC) is significantly improved through introducing nitrogen-doped carbon nanotubes (NCNTs) into the catalyst layer (CL) and microporous layer (MPL) of the membrane electrode assembly (MEA...

  8. Polypyrrole layered SPEES/TPA proton exchange membrane for direct methanol fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Neelakandan, S.; Kanagaraj, P. [PG & Research Department of Chemistry, Polymeric Materials Research Lab, Alagappa Government Arts College, Karaikudi 630003 (India); Sabarathinam, R.M. [Functional Material Division, Central Electrochemical Research Institute, Karaikudi 630006 (India); Nagendran, A., E-mail: nagimmm@yahoo.com [PG & Research Department of Chemistry, Polymeric Materials Research Lab, Alagappa Government Arts College, Karaikudi 630003 (India)

    2015-12-30

    Graphical abstract: - Highlights: • A series of Ppy layered SPEES/TPA composite membranes were prepared. • SPEES/TPA-Ppy hybrid membranes displayed efficient methanol resistance than Nafion 117. • SPEES/TPA-Ppy4 membrane exhibits highest relative selectivity of 2.86 × 104 S cm{sup 3} s. • Increasing Ppy layer on membrane surface reduces the leaching out of tungstophosphoric acid. - Abstract: Hybrid membranes based on sulfonated poly(1,4-phenylene ether ether sulfone) (SPEES)/tungstophosphoric acid (TPA) were prepared. SPEES/TPA membrane surfaces were modified with polypyrrole (Ppy) by in situ polymerization method to reduce the TPA leaching. The morphology and electrochemical property of the surface coated membranes were studied by SEM, AFM, water uptake, ion exchange capacity, proton conductivity, methanol permeability and tensile strength. The water uptake and the swelling ratio of the surface coated membranes decreased with increasing the Ppy layer. The surface roughness of the hybrid membrane was decreased with an increase in Ppy layer on the membrane surface. The methanol permeability of SPEES/TPA-Ppy4 hybrid membrane was significantly suppressed and found to be 2.1 × 10{sup −7} cm{sup 2} s{sup −1}, which is 1.9 times lower than pristine SPEES membrane. The SPEES/TPA-Ppy4 membrane exhibits highest relative selectivity (2.86 × 10{sup 4} S cm{sup −3} s) than the other membrane with low TPA leaching. The tensile strength of hybrid membranes was improved with the introduction of Ppy layer. Combining their lower swelling ratio, high thermal stability and selectivity, SPEES/TPA-Ppy4 membranes could be a promising material as PEM for DMFC applications.

  9. Polypyrrole layered SPEES/TPA proton exchange membrane for direct methanol fuel cells

    International Nuclear Information System (INIS)

    Neelakandan, S.; Kanagaraj, P.; Sabarathinam, R.M.; Nagendran, A.

    2015-01-01

    Graphical abstract: - Highlights: • A series of Ppy layered SPEES/TPA composite membranes were prepared. • SPEES/TPA-Ppy hybrid membranes displayed efficient methanol resistance than Nafion 117. • SPEES/TPA-Ppy4 membrane exhibits highest relative selectivity of 2.86 × 104 S cm"3 s. • Increasing Ppy layer on membrane surface reduces the leaching out of tungstophosphoric acid. - Abstract: Hybrid membranes based on sulfonated poly(1,4-phenylene ether ether sulfone) (SPEES)/tungstophosphoric acid (TPA) were prepared. SPEES/TPA membrane surfaces were modified with polypyrrole (Ppy) by in situ polymerization method to reduce the TPA leaching. The morphology and electrochemical property of the surface coated membranes were studied by SEM, AFM, water uptake, ion exchange capacity, proton conductivity, methanol permeability and tensile strength. The water uptake and the swelling ratio of the surface coated membranes decreased with increasing the Ppy layer. The surface roughness of the hybrid membrane was decreased with an increase in Ppy layer on the membrane surface. The methanol permeability of SPEES/TPA-Ppy4 hybrid membrane was significantly suppressed and found to be 2.1 × 10"−"7 cm"2 s"−"1, which is 1.9 times lower than pristine SPEES membrane. The SPEES/TPA-Ppy4 membrane exhibits highest relative selectivity (2.86 × 10"4 S cm"−"3 s) than the other membrane with low TPA leaching. The tensile strength of hybrid membranes was improved with the introduction of Ppy layer. Combining their lower swelling ratio, high thermal stability and selectivity, SPEES/TPA-Ppy4 membranes could be a promising material as PEM for DMFC applications.

  10. Roll-to-roll atomic layer deposition process for flexible electronics encapsulation applications

    International Nuclear Information System (INIS)

    Maydannik, Philipp S.; Kääriäinen, Tommi O.; Lahtinen, Kimmo; Cameron, David C.; Söderlund, Mikko; Soininen, Pekka; Johansson, Petri; Kuusipalo, Jurkka; Moro, Lorenza; Zeng, Xianghui

    2014-01-01

    At present flexible electronic devices are under extensive development and, among them, flexible organic light-emitting diode displays are the closest to a large market deployment. One of the remaining unsolved challenges is high throughput production of impermeable flexible transparent barrier layers that protect sensitive light-emitting materials against ambient moisture. The present studies deal with the adaptation of the atomic layer deposition (ALD) process to high-throughput roll-to-roll production using the spatial ALD concept. We report the development of such a process for the deposition of 20 nm thickness Al 2 O 3 diffusion barrier layers on 500 mm wide polymer webs. The process uses trimethylaluminum and water as precursors at a substrate temperature of 105 °C. The observation of self-limiting film growth behavior and uniformity of thickness confirms the ALD growth mechanism. Water vapor transmission rates for 20 nm Al 2 O 3 films deposited on polyethylene naphthalate (PEN) substrates were measured as a function of substrate residence time, that is, time of exposure of the substrate to one precursor zone. Moisture permeation levels measured at 38 °C/90% relative humidity by coulometric isostatic–isobaric method were below the detection limit of the instrument ( −4  g/m 2 day) for films coated at web moving speed of 0.25 m/min. Measurements using the Ca test indicated water vapor transmission rates ∼5 × 10 −6 g/m 2 day. Optical measurements on the coated web showed minimum transmission of 80% in the visible range that is the same as the original PEN substrate

  11. Roll-to-roll atomic layer deposition process for flexible electronics encapsulation applications

    Energy Technology Data Exchange (ETDEWEB)

    Maydannik, Philipp S., E-mail: philipp.maydannik@lut.fi; Kääriäinen, Tommi O.; Lahtinen, Kimmo; Cameron, David C. [Advanced Surface Technology Research Laboratory, Lappeenranta University of Technology, Sammonkatu 12, 50130 Mikkeli (Finland); Söderlund, Mikko; Soininen, Pekka [Beneq Oy, P.O. Box 262, 01511 Vantaa (Finland); Johansson, Petri; Kuusipalo, Jurkka [Tampere University of Technology, Paper Converting and Packaging Technology, P.O. Box 589, 33101 Tampere (Finland); Moro, Lorenza; Zeng, Xianghui [Samsung Cheil Industries, San Jose R and D Center, 2186 Bering Drive, San Jose, California 95131 (United States)

    2014-09-01

    At present flexible electronic devices are under extensive development and, among them, flexible organic light-emitting diode displays are the closest to a large market deployment. One of the remaining unsolved challenges is high throughput production of impermeable flexible transparent barrier layers that protect sensitive light-emitting materials against ambient moisture. The present studies deal with the adaptation of the atomic layer deposition (ALD) process to high-throughput roll-to-roll production using the spatial ALD concept. We report the development of such a process for the deposition of 20 nm thickness Al{sub 2}O{sub 3} diffusion barrier layers on 500 mm wide polymer webs. The process uses trimethylaluminum and water as precursors at a substrate temperature of 105 °C. The observation of self-limiting film growth behavior and uniformity of thickness confirms the ALD growth mechanism. Water vapor transmission rates for 20 nm Al{sub 2}O{sub 3} films deposited on polyethylene naphthalate (PEN) substrates were measured as a function of substrate residence time, that is, time of exposure of the substrate to one precursor zone. Moisture permeation levels measured at 38 °C/90% relative humidity by coulometric isostatic–isobaric method were below the detection limit of the instrument (<5 × 10{sup −4} g/m{sup 2} day) for films coated at web moving speed of 0.25 m/min. Measurements using the Ca test indicated water vapor transmission rates ∼5 × 10{sup −6} g/m{sup 2} day. Optical measurements on the coated web showed minimum transmission of 80% in the visible range that is the same as the original PEN substrate.

  12. Assessing the dynamics of the upper soil layer relative to soil management practices

    Science.gov (United States)

    Hatfield, J.; Wacha, K.; Dold, C.

    2017-12-01

    The upper layer of the soil is the critical interface between the soil and the atmosphere and is the most dynamic in response to management practices. One of the soil properties most reflective to changes in management is the stability of the aggregates because this property controls infiltration of water and exchange of gases. An aggregation model has been developed based on the factors that control how aggregates form and the forces which degrade aggregates. One of the major factors for this model is the storage of carbon into the soil and the interaction with the soil biological component. To increase soil biology requires a stable microclimate that provides food, water, shelter, and oxygen which in turn facilitates the incorporation of organic material into forms that can be combined with soil particles to create stable aggregates. The processes that increase aggregate size and stability are directly linked the continual functioning of the biological component which in turn changes the physical and chemical properties of the soil. Soil aggregates begin to degrade as soon as there is no longer a supply of organic material into the soil. These processes can range from removal of organic material and excessive tillage. To increase aggregation of the upper soil layer requires a continual supply of organic material and the biological activity that incorporates organic material into substances that create a stable aggregate. Soils that exhibit stable soil aggregates at the surface have a prolonged infiltration rate with less runoff and a gas exchange that ensures adequate oxygen for maximum biological activity. Quantifying the dynamics of the soil surface layer provides a quantitative understanding of how management practices affect aggregate stability.

  13. A study on water infiltration barriers with compacted layered soils

    International Nuclear Information System (INIS)

    Umeda, Y.; Komori, K.; Fujiwara, A.

    1993-01-01

    In shallow-ground disposal of low-level radioactive wastes, water movements due to natural processes in the soil covering the disposal facility must be properly controlled. A capillary barrier with compacted layered soils can provide an effective means of controlling water movement in the soil covering placed on a low-level radioactive waste disposal facility. An experiment was performed to determine the effectiveness of a full-scale fill as a capillary barrier. The fill used in the experiment was constructed of compacted layers of clay, fine sand, and gravel. Man-made rain was caused to fall on the surfaces of the fill to observe the infiltration of rainwater into the fill and to measure the amount of water drained from within. The experiment established the effectiveness of the capillary barrier

  14. Multi-layered nanoparticles for penetrating the endosome and nuclear membrane via a step-wise membrane fusion process.

    Science.gov (United States)

    Akita, Hidetaka; Kudo, Asako; Minoura, Arisa; Yamaguti, Masaya; Khalil, Ikramy A; Moriguchi, Rumiko; Masuda, Tomoya; Danev, Radostin; Nagayama, Kuniaki; Kogure, Kentaro; Harashima, Hideyoshi

    2009-05-01

    Efficient targeting of DNA to the nucleus is a prerequisite for effective gene therapy. The gene-delivery vehicle must penetrate through the plasma membrane, and the DNA-impermeable double-membraned nuclear envelope, and deposit its DNA cargo in a form ready for transcription. Here we introduce a concept for overcoming intracellular membrane barriers that involves step-wise membrane fusion. To achieve this, a nanotechnology was developed that creates a multi-layered nanoparticle, which we refer to as a Tetra-lamellar Multi-functional Envelope-type Nano Device (T-MEND). The critical structural elements of the T-MEND are a DNA-polycation condensed core coated with two nuclear membrane-fusogenic inner envelopes and two endosome-fusogenic outer envelopes, which are shed in stepwise fashion. A double-lamellar membrane structure is required for nuclear delivery via the stepwise fusion of double layered nuclear membrane structure. Intracellular membrane fusions to endosomes and nuclear membranes were verified by spectral imaging of fluorescence resonance energy transfer (FRET) between donor and acceptor fluorophores that had been dually labeled on the liposome surface. Coating the core with the minimum number of nucleus-fusogenic lipid envelopes (i.e., 2) is essential to facilitate transcription. As a result, the T-MEND achieves dramatic levels of transgene expression in non-dividing cells.

  15. Bacteria encapsulated in layered double hydroxides: towards an efficient bionanohybrid for pollutant degradation.

    Science.gov (United States)

    Halma, Matilte; Mousty, Christine; Forano, Claude; Sancelme, Martine; Besse-Hoggan, Pascale; Prevot, Vanessa

    2015-02-01

    A soft chemical process was successfully used to immobilize Pseudomonas sp. strain ADP (ADP), a well-known atrazine (herbicide) degrading bacterium, within a Mg2Al-layered double hydroxide host matrix. This approach is based on a simple, quick and ecofriendly direct coprecipitation of metal salts in the presence of a colloidal suspension of bacteria in water. It must be stressed that by this process the mass ratio between inorganic and biological components was easily tuned ranging from 2 to 40. This ratio strongly influenced the biological activity of the bacteria towards atrazine degradation. The better results were obtained for ratios of 10 or lower, leading to an enhanced atrazine degradation rate and percentage compared to free cells. Moreover the biohybrid material maintained this biodegradative activity after four cycles of reutilization and 3 weeks storage at 4°C. The ADP@MgAl-LDH bionanohybrid materials were completely characterized by X-ray diffraction (XRD), FTIR spectroscopy, thermogravimetric analysis and scanning and transmission electronic microscopy (SEM and TEM) evidencing the successful immobilization of ADP within the inorganic matrix. This synthetic approach could be readily extended to other microbial whole-cell immobilization of interest for new developments in biotechnological systems. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Pervaporation dehydration of ethanol by hyaluronic acid/sodium alginate two-active-layer composite membranes.

    Science.gov (United States)

    Gao, Chengyun; Zhang, Minhua; Ding, Jianwu; Pan, Fusheng; Jiang, Zhongyi; Li, Yifan; Zhao, Jing

    2014-01-01

    The composite membranes with two-active-layer (a capping layer and an inner layer) were prepared by sequential spin-coatings of hyaluronic acid (HA) and sodium alginate (NaAlg) on the polyacrylonitrile (PAN) support layer. The SEM showed a mutilayer structure and a distinct interface between the HA layer and the NaAlg layer. The coating sequence of two-active-layer had an obvious influence on the pervaporation dehydration performance of membranes. When the operation temperature was 80 °C and water concentration in feed was 10 wt.%, the permeate fluxes of HA/Alg/PAN membrane and Alg/HA/PAN membrane were similar, whereas the separation factor were 1130 and 527, respectively. It was found that the capping layer with higher hydrophilicity and water retention capacity, and the inner layer with higher permselectivity could increase the separation performance of the composite membranes. Meanwhile, effects of operation temperature and water concentration in feed on pervaporation performance as well as membrane properties were studied. Copyright © 2013 Elsevier Ltd. All rights reserved.

  17. Estimation of apparent soil resistivity for two-layer soil structure

    Energy Technology Data Exchange (ETDEWEB)

    Nassereddine, M.; Rizk, J.; Nagrial, M.; Hellany, A. [School of Computing, Engineering and Mathematics, University of Western Sydney (Australia)

    2013-07-01

    High voltage (HV) earthing design is one of the key elements when it comes to safety compliance of a system. High voltage infrastructure exposes workers and people to unsafe conditions. The soil structure plays a vital role in determining the allowable and actual step/touch voltage. This paper presents vital information when working with two-layer soil structure. It shows the process as to when it is acceptable to use a single layer instead of a two-layer structure. It also discusses the simplification of the soil structure approach depending on the reflection coefficient. It introduces the reflection coefficient K interval which determines if single layer approach is acceptable. Multiple case studies are presented to address the new approach and its accuracy.

  18. Double layer mixed matrix membrane adsorbers improving capacity and safety hemodialysis

    Science.gov (United States)

    Saiful; Borneman, Z.; Wessling, M.

    2018-05-01

    Double layer mixed matrix membranes adsorbers have been developed for blood toxin removal by embedding activated carbon into cellulose acetate macroporous membranes. The membranes are prepared by phase inversion method via water vapor induced phase separation followed by an immersion precipitation step. Double layer MMM consisting of an active support and a separating layer. The active support layer consists of activated carbon particles embedded in macroporous cellulose acetate; the separating layer consists of particle free cellulose acetate. The double layer membrane possess an open and interconnected macroporous structure with a high loading of activated carbon available for blood toxins removal. The MMM AC has a swelling degree of 6.5 %, porosity of 53 % and clean water flux of 800 Lm-2h-1bar-1. The prepared membranes show a high dynamic Creatinine (Crt) removal during hemodilysis process. The Crt removal by adsorption contributes to amore than 83 % of the total removal. The double layer adsorptive membrane proves hemodialysis membrane can integrated with adsorption, in which blood toxins are removed in one step.

  19. Irreversible fouling of membrane bioreactors due to formation of a non-biofilm gel layer

    DEFF Research Database (Denmark)

    Poorasgari, Eskandar; Larsen, Poul; Zheng, Xing

    2014-01-01

    Extra-cellular polymeric substances (EPS), known to contribute to fouling in membrane bio-reactors (MBRs), are generally divided into bound and free EPS. The free EPS are able to form a gel layer on the membrane active surface. The mechanisms involved in formation of such layer and its effects...... on performance of the MBR membranes were studied. The free EPS, extracted by centrifugation and microfiltration, contained a significant amount of humic-like substances. Under static contact to the membrane, adsorption of humic-like substances to the membrane occurred and could be explained by conventional...... adsorption kinetics. Due to static adsorption, surface roughness of the membrane declined significantly, indicating that adsorbed matters to the membranefilled the cavities of the membrane surface. Filtration of the free EPS caused 50% waterflux decline. The fouling resistance linearly increased...

  20. S-layer and cytoplasmic membrane – exceptions from the typical archaeal cell wall with a focus on double membranes

    Directory of Open Access Journals (Sweden)

    Andreas eKlingl

    2014-11-01

    Full Text Available The common idea of typical cell wall architecture in archaea consists of a pseudo-crystalline proteinaceous surface layer (S-layer, situated upon the cytoplasmic membrane. This is true for the majority of described archaea, hitherto. Within the crenarchaea, the S-layer often represents the only cell wall component, but there are various exceptions from this wall architecture. Beside (glycosylated S-layers in (hyperthermophilic cren- and euryarchaea as well as halophilic archaea, one can find a great variety of other cell wall structures like proteoglycan-like S-layers (Halobacteria, glutaminylglycan (Natronococci, methanochondroitin (Methanosarcina or double layered cell walls with pseudomurein (Methanothermus and Methanopyrus. The presence of an outermost cellular membrane in the crenarchaeal species Ignicoccus hospitalis already gave indications for an outer membrane similar to Gram-negative bacteria. Although there is just limited data concerning their biochemistry and ultrastructure, recent studies on the euryarchaeal methanogen Methanomassiliicoccus luminyensis, cells of the ARMAN group, and the SM1 euryarchaeon delivered further examples for this exceptional cell envelope type consisting of two membranes.

  1. Stable catalyst layers for hydrogen permeable composite membranes

    Science.gov (United States)

    Way, J. Douglas; Wolden, Colin A

    2014-01-07

    The present invention provides a hydrogen separation membrane based on nanoporous, composite metal carbide or metal sulfide coated membranes capable of high flux and permselectivity for hydrogen without platinum group metals. The present invention is capable of being operated over a broad temperature range, including at elevated temperatures, while maintaining hydrogen selectivity.

  2. Multi-layer membrane model for mass transport in a direct ethanol fuel cell using an alkaline anion exchange membrane

    Science.gov (United States)

    Bahrami, Hafez; Faghri, Amir

    2012-11-01

    A one-dimensional, isothermal, single-phase model is presented to investigate the mass transport in a direct ethanol fuel cell incorporating an alkaline anion exchange membrane. The electrochemistry is analytically solved and the closed-form solution is provided for two limiting cases assuming Tafel expressions for both oxygen reduction and ethanol oxidation. A multi-layer membrane model is proposed to properly account for the diffusive and electroosmotic transport of ethanol through the membrane. The fundamental differences in fuel crossover for positive and negative electroosmotic drag coefficients are discussed. It is found that ethanol crossover is significantly reduced upon using an alkaline anion exchange membrane instead of a proton exchange membrane, especially at current densities higher than 500 A m

  3. Filter Membrane Effects on Water-Extractable Phosphorus Concentrations from Soil.

    Science.gov (United States)

    Norby, Jessica; Strawn, Daniel; Brooks, Erin

    2018-03-01

    To accurately assess P concentrations in soil extracts, standard laboratory practices for monitoring P concentrations are needed. Water-extractable P is a common analytical test to determine P availability for leaching from soils, and it is used to determine best management practices. Most P analytical tests require filtration through a filter membrane with 0.45-μm pore size to distinguish between particulate and dissolved P species. However, filter membrane type is rarely specified in method protocols, and many different types of membranes are available. In this study, three common filter membrane materials (polyether sulfone, nylon, and nitrocellulose), all with 0.45-μm pore sizes, were tested for analytical differences in total P concentrations and dissolved reactive P (DRP) concentrations in water extracts from six soils sampled from two regions. Three of the extracts from the six soil samples had different total P concentrations for all three membrane types. The other three soil extracts had significantly different total P results from at least one filter membrane type. Total P concentration differences were as great as 35%. The DRP concentrations in the extracts were dependent on filter type in five of the six soil types. Results from this research show that filter membrane type is an important parameter that affects concentrations of total P and DRP from soil extracts. Thus, membrane type should be specified in soil extraction protocols. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  4. Characterization of magnetically enhanced buried soil layer in arid environment

    Science.gov (United States)

    Petrovsky, E.; Grison, H.; Kapicka, A.; Silva, P. F.; Font, E.

    2011-12-01

    Magnetic susceptibility (MS) of soils, reflecting the presence of magnetite/maghemite, can be used in several environmental applications. Magnetic topsoil mapping is often used to outline areas polluted by atmospherically deposited dust. However, in these studies, the magnetically enhanced layer is usually shallow, some 5-6 cm under the surface. In our contribution, we present the case when the magnetic susceptibility is enhanced in deeper soil layers. Investigated soils are mostly sandy soils, from several localities in Portugal, in a zone with arid climate. Sample profiles were collected always in forests or forest stands with pines, cork oaks or eucalyptus trees in two areas: around the city of Sines (on the coast south of Lisbon) and around the city of Abrantes (inland, north-east of Lisbon). Both areas are presumably affected by one major source of pollution - power plant. Surface magnetic susceptibility measurements were performed by Bartington MS2D loop; values vary from 10 to 300 x 10-5 SI units. Vertical distribution of magnetic susceptibility was measured already in situ using the SM400 (ZHInstruments) on profiles about 40cm in length. Mass-specific MS was determined using Bartington MS2B dual frequency meter and Agico MFK1. Nine vertical profiles were selected for detailed analyses including the ARM, IRM and hysteresis measurements. Distinctly enhanced magnetic layers were detected in deeper horizons. This enhancement can be ascribed to several mechanisms. Migration of magnetic particles seems to be probable, as observed in our model experiments with sand columns. In coastal areas, the enhanced layer could be due to tsunami deposits, as described in other areas. Finally, in particular at sites close to power plants, the construction works followed by surface remediation have to be also considered as one of the possible mechanisms.

  5. Structural Study and Modification of Support Layer for Forward Osmosis Membranes

    KAUST Repository

    Shi, Meixia

    2016-06-01

    Water scarcity is a serious global issue, due to the increasing population and developing economy, and membrane technology is an essential way to address this problem. Forward osmosis (FO) is an emerging membrane process, due to its low energy consumption (not considering the draw solute regeneration). A bottleneck to advance this technology is the design of the support layer for FO membranes to minimize the internal concentration polarization. In this dissertation, we focus on the structural study and modification of the support layer for FO membranes. Firstly, we digitally reconstruct different membrane morphologies in 3D and propose a method for predicting performance in ultrafiltration operations. Membranes with analogous morphologies are later used as substrate for FO membranes. Secondly, we experimentally apply substrates with different potentially suitable morphologies as an FO support layer. We investigate their FO performance after generating a selective polyamide layer on the top, by interfacial polymerization. Among the different substrates we include standard asymmetric porous membranes prepared from homopolymers, such as polysulfone. Additionally block copolymer membrane and Anodisc alumina membrane are chosen based on their exceptional structures, with cylindrical pores at least in part. 3D digitally reconstructed porous substrates, analogous to those investigated for ultrafiltration, are then used to model the performance in FO operation. Finally, we analyze the effect of intermediate layers between the porous substrate and the interfacial polymerized layer. We investigate two materials including chitosan and hydrogel. The main results are the following. Pore-scale modeling for digital membrane generation effectively predicts the velocity profile in different layers of the membrane and the performance in UF experiments. Flow simulations confirm the advantage of finger-like substrates over sponge-like ones, when high water permeance is sought

  6. Soil application of an encapsulated CO2 source and its potential for management of western corn rootworm larvae.

    Science.gov (United States)

    Schumann, M; Patel, A; Vidal, S

    2014-02-01

    Western corn rootworm (Diabrotica virgifera virgifera LeConte) larvae use carbon dioxide (CO2) to locate the roots of their hosts. This study investigated whether an encapsulated CO2 source (CO2-emitting capsules) is able to outcompete CO2 gradients established by corn root respiration in the soil. Furthermore, the following two management options with the capsules were tested in semifield experiments (0.5- to 1-m2 greenhouse plots): the disruption of host location and an "attract-and-kill" strategy in which larvae were lured to a soil insecticide (Tefluthrin) between the corn rows. The attract-and-kill strategy was compared with an application of Tefluthrin in the corn rows (conventional treatment) at 33 and 18% of the standard field application rate. Application of the CO2-emitting capsules 30 cm from the plant base increased CO2 levels near the application point for up to 20 d with a peak at day 10. Both the disruption of host location and an attract-and-kill strategy caused a slight but nonsignificant reduction in larval densities. The disruption of host location caused a 17% reduction in larval densities, whereas an attract-and-kill strategy with Tefluthrin added at 33 and 18% of the standard application rate caused a 24 and 27% reduction in larval densities, respectively. As presently formulated, the CO2-emitting capsules, either with or without insecticide, do not provide adequate control of western corn rootworm.

  7. Recent advances in multi-layer composite polymeric membranes for CO2 separation: A review

    Directory of Open Access Journals (Sweden)

    Zhongde Dai

    2016-07-01

    Full Text Available The development of multilayer composite membranes for CO2 separation has gained increasing attention due to the desire for energy efficient technologies. Multilayer composite membranes have many advantages, including the possibility to optimize membrane materials independently by layers according to their different functions and to reduce the overall transport resistance by using ultrathin selective layers, and less limitations on the material mechanical properties and processability. A comprehensive review is required to capture details of the progresses that have already been achieved in developing multilayer composite membranes with improved CO2 separation performance in the past 15–20 years. In this review, various composite membrane preparation methods were compared, advances in composite membranes for CO2/CH4 separation, CO2/N2 and CO2/H2 separation were summarized with detailed data, and challenges facing for the CO2 separation using composite membranes, such as aging, plasticization and long-term stability, were discussed. Finally the perspectives and future research directions for composite membranes were presented. Keywords: Composite membrane, CO2 separation, Membrane fabrication, Membrane aging, Long-term stability

  8. Response of the Atmospheric Boundary Layer and Soil Layer to a High Altitude, Dense Aerosol Cover.

    Science.gov (United States)

    Garratt, J. R.; Pittock, A. B.; Walsh, K.

    1990-01-01

    The response of the atmospheric boundary layer to the appearance of a high-altitude smoke layer has been investigated in a mesoscale numerical model of the atmosphere. Emphasis is placed on the changes in mean boundary-layer structure and near-surface temperatures when smoke of absorption optical depth (AOD) in the, range 0 to 1 is introduced. Calculations have been made at 30°S, for different soil thermal properties and degrees of surface wetness, over a time period of several days during which major smoke-induced cooling occurs. The presence of smoke reduces the daytime mixed-layer depth and, for large enough values of AOD, results in a daytime surface inversion with large cooling confined to heights of less than a few hundred meters. Smoke-induced reductions in daytime soil and air temperatures of several degrees are typical, dependent critically upon soil wetness and smoke AOD. Locations near the coast experience reduced cooling whenever there is a significant onshore flow related to a sea breeze (this would also be the case with a large-scale onshore flow). The sea breeze itself disappears for large enough smoke AOD and, over sloping coastal terrain, a smoke-induced, offshore drainage flow may exist throughout the diurnal cycle.

  9. Adsorption of pharmaceuticals onto isolated polyamide active layer of NF/RO membranes.

    Science.gov (United States)

    Liu, Yan-Ling; Wang, Xiao-Mao; Yang, Hong-Wei; Xie, Yuefeng F

    2018-06-01

    Adsorption of trace organic compounds (TrOCs) onto the membrane materials has a great impact on their rejection by nanofiltration (NF) and reverse osmosis (RO) membranes. This study aimed to investigate the difference in adsorption of various pharmaceuticals (PhACs) onto different NF/RO membranes and to demonstrate the necessity of isolating the polyamide (PA) active layer from the polysulfone (PS) support layer for adsorption characterization and quantification. Both the isolated PA layers and the PA+PS layers of NF90 and ESPA1 membranes were used to conduct static adsorption tests. Results showed that apparent differences existed between the PA layer and the PA+PS layer in the adsorption capacity of PhACs as well as the time necessary to reach the adsorption equilibrium. PhACs with different physicochemical properties could be adsorbed to different extents by the isolated PA layer, which was mainly attributed to electrostatic attraction/repulsion and hydrophobic interactions. The PA layer of ESPA1 exhibited apparently higher adsorption capacities for the positively charged PhACs and similar adsorption capacities for the neutral PhACs although it had significantly less total interfacial area (per unit membrane surface area) for adsorption compared to the PA layer of NF90. The higher affinity of the PA layer of ESPA1 for the PhACs could be due to its higher capacity of forming hydrogen bonds with PhACs resulted from the modified chemistry with more -OH groups. This study provides a novel approach to determining the TrOC adsorption onto the active layer of membranes for the ease of investigating adsorption mechanisms. Copyright © 2018 Elsevier Ltd. All rights reserved.

  10. A layer model of ethanol partitioning into lipid membranes.

    Science.gov (United States)

    Nizza, David T; Gawrisch, Klaus

    2009-06-01

    The effect of membrane composition on ethanol partitioning into lipid bilayers was assessed by headspace gas chromatography. A series of model membranes with different compositions have been investigated. Membranes were exposed to a physiological ethanol concentration of 20 mmol/l. The concentration of membranes was 20 wt% which roughly corresponds to values found in tissue. Partitioning depended on the chemical nature of polar groups at the lipid/water interface. Compared to phosphatidylcholine, lipids with headgroups containing phosphatidylglycerol, phosphatidylserine, and sphingomyelin showed enhanced partitioning while headgroups containing phosphatidylethanolamine resulted in a lower partition coefficient. The molar partition coefficient was independent of a membrane's hydrophobic volume. This observation is in agreement with our previously published NMR results which showed that ethanol resides almost exclusively within the membrane/water interface. At an ethanol concentration of 20 mmol/l in water, ethanol concentrations at the lipid/water interface are in the range from 30-15 mmol/l, corresponding to one ethanol molecule per 100-200 lipids.

  11. [Soil basal respiration and enzyme activities in the root-layer soil of tea bushes in a red soil].

    Science.gov (United States)

    Yu, Shen; He, Zhenli; Zhang, Rongguang; Chen, Guochao; Huang, Changyong

    2003-02-01

    Soil basal respiration potential, metabolic quotient (qCO2), and activities of urease, invertase and acid phosphomonoesterase were investigated in the root-layer of 10-, 40-, and 90-yr-old tea bushes grown on the same type of red soil. The soil daily basal respiration potential ranged from 36.23 to 58.52 mg.kg-1.d-1, and the potentials in the root-layer of 40- or 90-yr-old were greater than that of 10-yr old tea bushes. The daily qCO2, ranging from 0.30 to 0.68, was in the reverse trend. The activities of test three enzymes changed differently with tea bushes' age. Urease activity in the root-layer of all age tea bushes ranged from 41.48 to 47.72 mg.kg-1.h-1 and slightly decreased with tea bushes' age. Invertase activity was 189.29-363.40 mg.kg-1.h-1 and decreased with tea bushes' age, but its activity in the root-layer of 10-year old tea bushes was significantly greater than that in the root-layer soil of 40- or 90-year old tea bushes. Acid phosphomonoesterase activity (444.22-828.32 mg.kg-1.h-1) increased significantly with tea bushes' age. Soil basal respiration potential, qCO2 and activities of 3 soil enzymes were closely related to soil pH, soil organic carbon, total nitrogen and C/N ratio, total soluble phenol, and microbial biomass carbon, respectively.

  12. The performance of double layer structure membrane prepared from flowing coagulant

    Science.gov (United States)

    Mieow Kee, Chan; Xeng, Anthony Leong Chan; Regal, Sasiskala; Singh, Balvinder; Raoo, Preeshaath; Koon Eu, Yap; Sok Choo, Ng

    2017-12-01

    Membrane with double layer structure is favourable as it exhibits smooth surface and macrovoids free structure. However, its’ performance in terms of permeability, porosity and strength has not been studied thoroughly. Additionally, the effect of flowing coagulant on the formation of double layer membrane has not been reported. Thus, the objective of this study is to investigate the performance of double layer membranes, which were prepared using flowing coagulant. Results showed that when the coagulant flow changed from laminar to turbulent, the pure water permeation of the membrane increased. It was due to the higher porosity in the membrane, which prepared by turbulent flow (CA-Turbulent) compared to the membrane which fabricated under laminar condition (CA-Laminar). This can be explained by the rapid solvent-coagulant exchange rate between the polymer solution and the turbulent coagulant. In term of strength, the tensile strength of the CA-Turbulent was ~32 MPa, which was 100% higher compared to CA-Laminar. This may due to the presence of large amount of nodules on its surface, which reduced the surface integrity. In conclusion, flowing coagulant altered the membrane properties and adopting turbulent coagulant flow in membrane fabrication would improve the porosity, surface roughness and the strength of the membrane.

  13. Effects of a layer of vegetative ash layer on wettable and water repellent soil hydrology

    Science.gov (United States)

    Bodí, Merche B.; Doerr, Stefan H.; Cerdà, Artemi; Mataix-Solera, Jorge

    2010-05-01

    Following a wildfire, a layer of vegetative ash often covers the ground until it is dissolved or redistributed by wind and water erosion. Much of the existing literature suggests that the ash layer temporally reduces infiltration by clogging soil pores or by forming a surface crust (Mallik et al., 1984; Onda et al., 2008). However, an increasing number of field-based studies have found that, at least in the short term, ash increases infiltration by storing rainfall and protecting the underlying soil from sealing (Cerdà and Doerr, 2008; Woods and Balfour, 2008). On the other hand, after a fire the soil may have produced, enhanced or reduced its water repellency (Doerr et al., 2000). Very few studies have been taken into account the interaction of the ash and the repellent soil. The layer of ash may have similar role as a litter layer in delaying runoff and reducing erosion by storing water. In order to examine this interaction, it was been made a series of experiments using a laboratory rainfall simulation. It has been assessed the effects of an ash layer i) on a wettable and water repellent soil (WDPT > 7200s), ii) with different ash thicknesses (bare soil and 5 mm, 15 mm and 30 mm of ash), iii) preceding and following the first rain after a fire when the ground is still wetted and after being partially dried. Three replicates were done, being a total of 40 simulations. The ash used was collected from a Wildfire in Teruel (Spain) during summer of 2009. The simulations were conducted in metal boxes of 30x30 cm and filled with 3 cm of soil. The slope of the box was set at 10° (17%) and the intensity applied was 78-84 mm h-1during 40 minutes. The splash detachment was determined also using four splash cups. Overland flow and subsurface drainage was collected at 1-minute intervals and the former stored every 5 min to allow determination of sediment concentrations, yield and erosion rates. Each sample was examined at the end in terms of water repellency, infiltration

  14. Migration of cesium-137 through sandy soil layer effect of fine silt on migration

    International Nuclear Information System (INIS)

    Ohnuki, Toshihiko; Wadachi, Yoshiki

    1983-01-01

    The migration of 137 Cs through sandy soil layer was studied with consideration of the migration of fine silt by column method. It was found that a portion of fine silt migrated through the soil layer accompanying with 137 Cs. The mathematical migration model of 137 Cs involved the migration of fine silt through such soil layer was presented. This model gave a good accordance between calculated concentration distribution curve in sandy soil layer and effluent curve and observed those. So, this model seems to be advanced one for evaluating migration of 137 Cs in sandy soil layer with silt. (author)

  15. A new insight into membrane fouling mechanism in submerged membrane bioreactor: osmotic pressure during cake layer filtration.

    Science.gov (United States)

    Zhang, Meijia; Peng, Wei; Chen, Jianrong; He, Yiming; Ding, Linxian; Wang, Aijun; Lin, Hongjun; Hong, Huachang; Zhang, Ye; Yu, Haiying

    2013-05-15

    Big gap between experimental filtration resistance of cake layer formed on membrane surface and the hydraulic resistance calculated through the Carman-Kozeny equation, suggested the existence of a new membrane fouling mechanism: osmotic pressure during cake layer filtration in SMBR system. An osmotic pressure model based on chemical potential difference was then proposed. Simulation of the model showed that osmotic pressure accounted for the major fraction of total operation pressure, and pH, applied pressure and ionic strength were the key determining factors for osmosis effect. It was found that, variations of osmotic pressure with pH, applied pressure and added ionic strength were well coincident with perditions of model's simulation, providing the first direct evidences of the real occurrence of osmosis mechanism and the feasibility of the proposed model. These findings illustrate the essential role of osmotic pressure in filtration resistance, and improve fundamental understanding on membrane fouling in SMBR systems. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. Hierarchical Composite Membranes with Robust Omniphobic Surface Using Layer-By-Layer Assembly Technique

    KAUST Repository

    Woo, Yun Chul; Kim, Youngjin; Yao, Minwei; Tijing, Leonard Demegilio; Choi, Juneseok; Lee, Sangho; Kim, Seunghyun; Shon, Hokyong

    2018-01-01

    gave the LBL membrane an omniphobic property, as indicated by its good wetting resistance. The membrane performed a stable air gap membrane distillation (AGMD) flux of 11.22 L/m2h with very high salt rejection using reverse osmosis brine from coal seam

  17. Erythrocyte membrane-encapsulated celecoxib improves the cognitive decline of Alzheimer's disease by concurrently inducing neurogenesis and reducing apoptosis in APP/PS1 transgenic mice.

    Science.gov (United States)

    Guo, Jing-Wen; Guan, Pei-Pei; Ding, Wei-Yan; Wang, Si-Ling; Huang, Xue-Shi; Wang, Zhan-You; Wang, Pu

    2017-11-01

    Alzheimer's disease (AD) is characterized by the loss of neurogenesis and excessive induction of apoptosis. The induction of neurogenesis and inhibition of apoptosis may be a promising therapeutic approach to combating the disease. Celecoxib (CB), a cyclooxygenase-2 specific inhibitor, could offer neuroprotection. Specifically, the CB-encapsulated erythrocyte membranes (CB-RBCMs) sustained the release of CB over a period of 72 h in vitro and exhibited high brain biodistribution efficiency following intranasal administration, which resulted in the clearance of aggregated β-amyloid proteins (Aβ) in neurons. The high accumulation of the CB-RBCMs in neurons resulted in a decrease in the neurotoxicity of CB and an increase in the migratory activity of neurons, and alleviated cognitive decline in APP/PS1 transgenic (Tg) mice. Indeed, COX-2 metabolic products including prostaglandin E2 (PGE 2 ) and PGD 2 , PGE 2 induced neurogenesis by enhancing the expression of SOD2 and 14-3-3ζ, and PGD 2 stimulated apoptosis by increasing the expression of BIK and decreasing the expression of ARRB1. To this end, the CB-RBCMs achieved better effects on concurrently increasing neurogenesis and decreasing apoptosis than the phospholipid membrane-encapsulated CB liposomes (CB-PSPD-LPs), which are critical for the development and progression of AD. Therefore, CB-RBCMs provide a rational design to treat AD by promoting the self-repairing capacity of the brain. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Self-assembling layers created by membrane proteins on gold.

    Science.gov (United States)

    Shah, D S; Thomas, M B; Phillips, S; Cisneros, D A; Le Brun, A P; Holt, S A; Lakey, J H

    2007-06-01

    Membrane systems are based on several types of organization. First, amphiphilic lipids are able to create monolayer and bilayer structures which may be flat, vesicular or micellar. Into these structures membrane proteins can be inserted which use the membrane to provide signals for lateral and orientational organization. Furthermore, the proteins are the product of highly specific self-assembly otherwise known as folding, which mostly places individual atoms at precise places in three dimensions. These structures all have dimensions in the nanoscale, except for the size of membrane planes which may extend for millimetres in large liposomes or centimetres on planar surfaces such as monolayers at the air/water interface. Membrane systems can be assembled on to surfaces to create supported bilayers and these have uses in biosensors and in electrical measurements using modified ion channels. The supported systems also allow for measurements using spectroscopy, surface plasmon resonance and atomic force microscopy. By combining the roles of lipids and proteins, highly ordered and specific structures can be self-assembled in aqueous solution at the nanoscale.

  19. Effect of enzyme location on activity and stability of trypsin and urease immobilized on porous membranes by using layer-by-layer self-assembly of polyelectrolyte

    OpenAIRE

    Guedidi, Sadika; Yürekli, Yılmaz; Deratani, André; Déjardin, Philippe; Innocent, Christophe; Altınkaya, Sacide; Roudesli, Sadok; Yemenicioğlu, Ahmet

    2010-01-01

    The layer-by-layer (LbL) self-assembly of polyelectrolyte is one of the simplest ways to immobilize enzyme on membrane. In this paper, the immobilization of trypsin (TRY) and urease (URE) on polyacrylonitrile based membranes using the LbL assembly technique was presented. The studied systems consisted in bilayered assemblies with the enzyme layer as the outer layer and trilayered assemblies with the enzyme layer as the inner sandwiched layer. The membrane pore size was chosen so that the smal...

  20. Performance enhancement of polymer electrolyte membrane fuel cells by dual-layered membrane electrode assembly structures with carbon nanotubes.

    Science.gov (United States)

    Jung, Dong-Won; Kim, Jun-Ho; Kim, Se-Hoon; Kim, Jun-Bom; Oh, Eun-Suok

    2013-05-01

    The effect of dual-layered membrane electrode assemblies (d-MEAs) on the performance of a polymer electrolyte membrane fuel cell (PEMFC) was investigated using the following characterization techniques: single cell performance test, electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV). It has been shown that the PEMFC with d-MEAs has better cell performance than that with typical mono-layered MEAs (m-MEAs). In particular, the d-MEA whose inner layer is composed of multi-walled carbon nanotubes (MWCNTs) showed the best fuel cell performance. This is due to the fact that the d-MEAs with MWCNTs have the highest electrochemical surface area and the lowest activation polarization, as observed from the CV and EIS test.

  1. Anion-exchange membranes derived from quaternized polysulfone and exfoliated layered double hydroxide for fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Wan; Liang, Na; Peng, Pai; Qu, Rong; Chen, Dongzhi; Zhang, Hongwei, E-mail: hanqiujiang@163.com

    2017-02-15

    Layered double hydroxides (LDH) are prepared by controlling urea assisted homogeneous precipitation conditions. Morphology and crystallinity of LDHs are confirmed by X-ray diffraction and scanning electron microscope. After LDHs are incorporated into quaternized polysulfone membranes, transmission electron microscope is used to observe the exfoliated morphology of LDH sheets in the membranes. The properties of the nanocomposite membranes, including water uptake, swelling ratio, mechanical property and ionic conductivity are investigated. The nanocomposite membrane containing 5% LDH sheets shows more balanced performances, exhibiting an ionic conductivity of 2.36×10{sup −2} S cm{sup −1} at 60 °C. - Graphical abstract: Anion-exchange membrane based on quaternized polysulfone and exfoliated layered double hydroxide is optically transparent and has good ionic properties.

  2. The vascular basement membrane as "soil" in brain metastasis.

    Directory of Open Access Journals (Sweden)

    W Shawn Carbonell

    2009-06-01

    Full Text Available Brain-specific homing and direct interactions with the neural substance are prominent hypotheses for brain metastasis formation and a modern manifestation of Paget's "seed and soil" concept. However, there is little direct evidence for this "neurotropic" growth in vivo. In contrast, many experimental studies have anecdotally noted the propensity of metastatic cells to grow along the exterior of pre-existing vessels of the CNS, a process termed vascular cooption. These observations suggest the "soil" for malignant cells in the CNS may well be vascular, rather than neuronal. We used in vivo experimental models of brain metastasis and analysis of human clinical specimens to test this hypothesis. Indeed, over 95% of early micrometastases examined demonstrated vascular cooption with little evidence for isolated neurotropic growth. This vessel interaction was adhesive in nature implicating the vascular basement membrane (VBM as the active substrate for tumor cell growth in the brain. Accordingly, VBM promoted adhesion and invasion of malignant cells and was sufficient for tumor growth prior to any evidence of angiogenesis. Blockade or loss of the beta1 integrin subunit in tumor cells prevented adhesion to VBM and attenuated metastasis establishment and growth in vivo. Our data establishes a new understanding of CNS metastasis formation and identifies the neurovasculature as the critical partner for such growth. Further, we have elucidated the mechanism of vascular cooption for the first time. These findings may help inform the design of effective molecular therapies for patients with fatal CNS malignancies.

  3. Electrochemical charging of the single-layer graphene membrane

    Czech Academy of Sciences Publication Activity Database

    Komínková, Zuzana; Kalbáč, Martin

    2016-01-01

    Roč. 253, č. 12 (2016), s. 2331-2335 ISSN 0370-1972 R&D Projects: GA MŠk LL1301; GA ČR(CZ) GBP208/12/G016 Institutional support: RVO:61388955 Keywords : electrochemical charging * graphene membrane * in situ Raman spectroelectrochemistry Subject RIV: CG - Electrochemistry Impact factor: 1.674, year: 2016

  4. Preparation of Two-Layer Anion-Exchange Poly(ethersulfone Based Membrane: Effect of Surface Modification

    Directory of Open Access Journals (Sweden)

    Lucie Zarybnicka

    2016-01-01

    Full Text Available The present work deals with the surface modification of a commercial microfiltration poly(ethersulfone membrane by graft polymerization technique. Poly(styrene-co-divinylbenzene-co-4-vinylbenzylchloride surface layer was covalently attached onto the poly(ethersulfone support layer to improve the membrane electrochemical properties. Followed by amination, a two-layer anion-exchange membrane was prepared. The effect of surface layer treatment using the extraction in various solvents on membrane morphological and electrochemical characteristics was studied. The membranes were tested from the point of view of water content, ion-exchange capacity, specific resistance, permselectivity, FT-IR spectroscopy, and SEM analysis. It was found that the two-layer anion-exchange membranes after the extraction using tetrahydrofuran or toluene exhibited smooth and porous surface layer, which resulted in improved ion-exchange capacity, electrical resistance, and permselectivity of the membranes.

  5. Compressibility of the fouling layer formed by membrane bioreactor sludge and supernatant

    DEFF Research Database (Denmark)

    Jørgensen, Mads Koustrup; Poorasgari, Eskandar; Christensen, Morten Lykkegaard

    Membrane bioreactors (MBR) are increasingly used for wastewater treatment as they give high effluent quality, low footprint and efficient sludge degradation. However, the accumulation and deposition of sludge components on and within the membrane (fouling) limits the widespread application of MBR....... Compressibility of the gel layer was studied in a dead-end filtration system, whereas the compressibility of a fouling layer formed by MBR sludge was studied in a submerged system hollow sheet membrane by TMP stepping. It was shown that the fouling layer formed by the MBR sludge was highly compressible within....... Hence, for MBR systems operated at constant flux mode, the applied pressure should be increased over time, to compensate for the lower permeability. Increasing applied pressure causes compression of the fouling layer and results in a more severe permeability decline [1]. In a general view, the fouling...

  6. Effects of forest conversion on soil microbial communities depend on soil layer on the eastern Tibetan Plateau of China.

    Directory of Open Access Journals (Sweden)

    Ruoyang He

    Full Text Available Forest land-use changes have long been suggested to profoundly affect soil microbial communities. However, how forest type conversion influences soil microbial properties remains unclear in Tibetan boreal forests. The aim of this study was to explore variations of soil microbial profiles in the surface organic layer and subsurface mineral soil among three contrasting forests (natural coniferous forest, NF; secondary birch forest, SF and spruce plantation, PT. Soil microbial biomass, activity and community structure of the two layers were investigated by chloroform fumigation, substrate respiration and phospholipid fatty acid analysis (PLFA, respectively. In the organic layer, both NF and SF exhibited higher soil nutrient levels (carbon, nitrogen and phosphorus, microbial biomass carbon and nitrogen, microbial respiration, PLFA contents as compared to PT. However, the measured parameters in the mineral soils often did not differ following forest type conversion. Irrespective of forest types, the microbial indexes generally were greater in the organic layer than in the mineral soil. PLFAs biomarkers were significantly correlated with soil substrate pools. Taken together, forest land-use change remarkably altered microbial community in the organic layer but often did not affect them in the mineral soil. The microbial responses to forest land-use change depend on soil layer, with organic horizons being more sensitive to forest conversion.

  7. Potential Use of Polyacrylamide Encapsulation for Treatment of Petroleum Drilling Cuttings and Hydrocarbon Contaminated Soil

    Directory of Open Access Journals (Sweden)

    Randy H. Adams

    2011-07-01

    Full Text Available Mineral soil of alluvial origin, contaminated with diesel+lubricating oil (1:2, was treated with a commercial polyacrylamide product at 100 % of the distributer recommended dosage, producing a reduction in hydrocarbon concentration (EPA 9074 of 76 % that remained stable during the study period (38 days and even after thermal treatment (60 ºC, 18 hrs.. Increasing the dosage to 150 % did not improve the treatment results, but repeating the treatment (at 100 % resulted in a slight additional reduction (4 %. Similar results were obtained with oil-based drilling cuttings (~60 % reduction at both 100 % and 150 %. Pre-drying of the drilling cuttings prior to treatment did not improve the hydrocarbon reduction, but it did produce smaller, potentially more stable aggregates (0.5 – 1-0 mm in diameter. The treatment of organic soil resulted in a similar reduction in hydrocarbon concentration (65 % and a reduction of acute toxicity (Microtox to below background levels, however this effect was not stable. An additional application (including mixing of the polyacrylamide product resulted in partial disintegration of the organic fibres and release of the stabilized hydrocarbons, measuring an overall increase in hydrocarbon concentration of 19 %.

  8. Design and Test of a Soil Profile Moisture Sensor Based on Sensitive Soil Layers

    Science.gov (United States)

    Liu, Cheng; Qian, Hongzhou; Cao, Weixing; Ni, Jun

    2018-01-01

    To meet the demand of intelligent irrigation for accurate moisture sensing in the soil vertical profile, a soil profile moisture sensor was designed based on the principle of high-frequency capacitance. The sensor consists of five groups of sensing probes, a data processor, and some accessory components. Low-resistivity copper rings were used as components of the sensing probes. Composable simulation of the sensor’s sensing probes was carried out using a high-frequency structure simulator. According to the effective radiation range of electric field intensity, width and spacing of copper ring were set to 30 mm and 40 mm, respectively. A parallel resonance circuit of voltage-controlled oscillator and high-frequency inductance-capacitance (LC) was designed for signal frequency division and conditioning. A data processor was used to process moisture-related frequency signals for soil profile moisture sensing. The sensor was able to detect real-time soil moisture at the depths of 20, 30, and 50 cm and conduct online inversion of moisture in the soil layer between 0–100 cm. According to the calibration results, the degree of fitting (R2) between the sensor’s measuring frequency and the volumetric moisture content of soil sample was 0.99 and the relative error of the sensor consistency test was 0–1.17%. Field tests in different loam soils showed that measured soil moisture from our sensor reproduced the observed soil moisture dynamic well, with an R2 of 0.96 and a root mean square error of 0.04. In a sensor accuracy test, the R2 between the measured value of the proposed sensor and that of the Diviner2000 portable soil moisture monitoring system was higher than 0.85, with a relative error smaller than 5%. The R2 between measured values and inversed soil moisture values for other soil layers were consistently higher than 0.8. According to calibration test and field test, this sensor, which features low cost, good operability, and high integration, is qualified for

  9. Nanoporous layered silicate AMH-3/cellulose acetate nanocomposite membranes for gas separations

    KAUST Repository

    Kim, Wun-gwi

    2013-08-01

    Nanoporous layered silicate/polymer composite membranes are of interest because they can exploit the high aspect ratio of exfoliated selective flakes/layers to enhance molecular sieving and create a highly tortuous transport path for the slower molecules. In this work, we combine membrane synthesis, detailed microstructural characterization, and mixed gas permeation measurements to demonstrate that nanoporous flake/polymer membranes allows significant improvement in gas permeability while maintaining selectivity. We begin with the primary-amine-intercalated porous layered silicate SAMH-3 and show that it can be exfoliated using a high shear rate generated by a high-speed mixer. The exfoliated SAMH-3 flakes were used to form SAMH-3/cellulose acetate (CA) membranes. Their microstructure was analyzed by small angle X-ray scattering (SAXS), revealing a high degree of exfoliation of AMH-3 layers in the CA membrane with a small number of layers (4-8) in the exfoliated flakes. TEM analysis visualized the thickness of the flakes as 15-30nm, and is consistent with the SAXS analysis. The CO2/CH4 gas separation performance of the CA membrane was significantly increased by incorporating only 2-6wt% of SAMH-3 flakes. There was a large increase in CO2 permeability with maintenance of selectivity. This cannot be explained by conventional models of transport in flake-containing membranes, and indicates complex transport paths in the membrane. It is also in contrast to the much higher loadings of isotropic particles required for similar enhancements. The present approach may allow avoidance of particle aggregation and poor interfacial adhesion associated with larger quantities of inorganic fillers. © 2013 Elsevier B.V.

  10. Incorporation of layered double nanomaterials in thin film nanocomposite nanofiltration membrane for magnesium sulphate removal

    Directory of Open Access Journals (Sweden)

    Tajuddin Muhammad Hanis

    2018-01-01

    Full Text Available Thin film nanocomposite (TFN membrane with copper-aluminium layered double hydroxides (LDH incorporated into polyamide (PA selective layer has been prepared for magnesium sulphate salt removal. 0, 0.05, 0.1, 0.15, 0.2 wt% of LDH were dispersed in the trimesoyl chloride (TMC in n-hexane as organic solution and embedded into PA layer during interfacial polymerization with piperazine. The fabricated membranes were further characterized to evaluate its morphological structure and membrane surface hydrophilicity. The TFN membranes performance were evaluated with divalent salt magnesium sulphate (MgSO4 removal and compared with thin film composite (TFC. The morphological structures of TFN membranes were altered and the surface hydrophilicity were enhanced with addition of LDH. Incorporation of LDH has improved the permeate water flux by 82.5% compared to that of TFC membrane with satisfactory rejection of MgSO4. This study has experimentally validated the potential of LDH to improve the divalent salt separation performance for TFN membranes.

  11. Incorporation of layered double nanomaterials in thin film nanocomposite nanofiltration membrane for magnesium sulphate removal

    Science.gov (United States)

    Hanis Tajuddin, Muhammad; Yusof, Norhaniza; Salleh, Wan Norharyati Wan; Fauzi Ismail, Ahmad; Hanis Hayati Hairom, Nur; Misdan, Nurasyikin

    2018-03-01

    Thin film nanocomposite (TFN) membrane with copper-aluminium layered double hydroxides (LDH) incorporated into polyamide (PA) selective layer has been prepared for magnesium sulphate salt removal. 0, 0.05, 0.1, 0.15, 0.2 wt% of LDH were dispersed in the trimesoyl chloride (TMC) in n-hexane as organic solution and embedded into PA layer during interfacial polymerization with piperazine. The fabricated membranes were further characterized to evaluate its morphological structure and membrane surface hydrophilicity. The TFN membranes performance were evaluated with divalent salt magnesium sulphate (MgSO4) removal and compared with thin film composite (TFC). The morphological structures of TFN membranes were altered and the surface hydrophilicity were enhanced with addition of LDH. Incorporation of LDH has improved the permeate water flux by 82.5% compared to that of TFC membrane with satisfactory rejection of MgSO4. This study has experimentally validated the potential of LDH to improve the divalent salt separation performance for TFN membranes.

  12. Sintering process optimization for multi-layer CGO membranes by in situ techniques

    DEFF Research Database (Denmark)

    Kaiser, Andreas; Prasad, A.S.; Foghmoes, Søren Preben Vagn

    2013-01-01

    The sintering of asymmetric CGO bi-layers (thin dense membrane on a porous support; Ce0.9Gd0.1O1.95-delta = CGO) with Co3O4 as sintering additive has been optimized by combination of two in situ techniques. Optical dilatometry revealed that bi-layer shape and microstructure are dramatically...... changing in a narrow temperature range of less than 100 degrees C. Below 1030 degrees C, a higher densification rate in the dense membrane layer than in the porous support leads to concave shape, whereas the densification rate of the support is dominant above 1030 degrees C, leading to convex shape. A fiat...... bi-layer could be prepared at 1030 degrees C, when shrinkage rates were similar. In situ van der Pauw measurements on tape cast layers during sintering allowed following the conductivity during sintering. A strong increase in conductivity and in activation energy E-a for conduction was observed...

  13. Micro-Encapsulation of Probiotics

    Science.gov (United States)

    Meiners, Jean-Antoine

    Micro-encapsulation is defined as the technology for packaging with the help of protective membranes particles of finely ground solids, droplets of liquids or gaseous materials in small capsules that release their contents at controlled rates over prolonged periods of time under the influences of specific conditions (Boh, 2007). The material encapsulating the core is referred to as coating or shell.

  14. Chemical composition of the humus layer, mineral soil and soil solution of 200 forest stands in the Netherlands in 1995

    NARCIS (Netherlands)

    Leeters, E.E.J.M.; Vries, de W.

    2001-01-01

    A nationwide assessment of the chemical composition of the soil solid phase and the soil solution in the humus layer and two mineral layers (0-10 cm and 10-30 cm) was made for 200 forest stands in the year 1995. The stands were part of the national forest inventory on vitality, included seven tree

  15. Solute transport model for radioisotopes in layered soil

    International Nuclear Information System (INIS)

    Essel, P.

    2010-01-01

    The study considered the transport of a radioactive solute in solution from the surface of the earth down through the soil to the ground water when there is an accidental or intentional spillage of a radioactive material on the surface. The finite difference method was used to model the spatial and temporal profile of moisture content in a soil column using the θ-based Richard's equation leading to solution of the convective-dispersive equation for non-adsorbing solutes numerically. A matlab code has been generated to predict the transport of the radioactive contaminant, spilled on the surface of a vertically heterogeneous soil made up of two layers to determine the residence time of the solute in the unsaturated zone, the time it takes the contaminant to reach the groundwater and the amount of the solute entering the groundwater in various times and the levels of pollution in those times. The model predicted that, then there is a spillage of 7.2g of tritium, on the surface of the ground at the study area, it will take two years for the radionuclide to enter the groundwater and fifteen years to totally leave the unsaturated zone. There is therefore the need to try as much as possible to avoid intentional or accidental spillage of the radionuclide since it has long term effect. (au)

  16. Soil physico-chemical characterization in the different soil layers of National Maize Research Program, Rampur, Chitwan, Nepal

    Directory of Open Access Journals (Sweden)

    Dinesh Khadka

    2017-12-01

    Full Text Available Soil pit digging and their precise study is a decision making tool to assess history and future of soil management of a particular area. Thus, the present study was carried out to differentiate soil physico-chemical properties in the different layers of excavated pit of the National Maize Research Program, Rampur, Chitwan, Nepal. Eight pits were dug randomly from three blocks at a depth of 0 to 100 cm. The soil parameters were determined in-situ, and in laboratory for texture, pH, OM, N, P (as P2O5, K (as K2O, Ca, Mg, S, B, Fe, Zn, Cu and Mn of collected soils samples of different layers following standard analytical methods at Soil Science Division, Khumaltar. The result revealed that soil structure was sub-angular in majority of the layers, whereas bottom layer was single grained. The value and chrome of colour was increasing in order from surface to bottom in the majority pits. Similarly, the texture was sandy loam in majority layers of the pits. Moreover, four types of consistence (loose to firm were observed. Furthermore, mottles and gravels were absent in the majority layers. Likewise, soil was very to moderately acidic in observed layers of majority pits, except bottom layer of agronomy block was slightly acidic. Regarding fertility parameters (OM, macro and micronutrients, some were increasing and vice-versa, while others were intermittent also. Therefore, a single layer is not dominant for particular soil physico-chemical parameters in the farm. In overall, surface layer is more fertile than rest of the layers in all the pits.

  17. Electrical evaluation of crack generation in SiN_x and SiO_xN_y thin-film encapsulation layers for OLED displays

    International Nuclear Information System (INIS)

    Park, Eun Kil; Kim, Sungmin; Heo, Jaeyeong; Kim, Hyeong Joon

    2016-01-01

    Highlights: • Crack generation in encapsulation layers were detected by leakage current. • Atomic concentration of SiO_xN_y films affected the bending reliability. • The shapes of the crack tips were affected by the stoichiometry of the SiO_xN_y films. - Abstract: By measuring leakage current density, we detected crack generation in silicon nitride (SiN_x) and silicon oxynitride (SiO_xN_y) thin-film encapsulation layers, and correlated with the films’ water vapor permeability characteristics. After repeated bending cycles, both the changes in water vapor transmission rate and leakage current density were directly proportional to the crack density. Thick SiN_x films had better water vapor barrier characteristics in their pristine state, but cyclic loading led to fast failure. Varying the atomic concentration of the SiO_xN_y films affected their bending reliability. We attribute these differences to changes in the shape of the crack tip as the oxygen content varies.

  18. Is There Excitation Energy Transfer between Different Layers of Stacked Photosystem-II-Containing Thylakoid Membranes?

    Science.gov (United States)

    Farooq, Shazia; Chmeliov, Jevgenij; Trinkunas, Gediminas; Valkunas, Leonas; van Amerongen, Herbert

    2016-04-07

    We have compared picosecond fluorescence decay kinetics for stacked and unstacked photosystem II membranes in order to evaluate the efficiency of excitation energy transfer between the neighboring layers. The measured kinetics were analyzed in terms of a recently developed fluctuating antenna model that provides information about the dimensionality of the studied system. Independently of the stacking state, all preparations exhibited virtually the same value of the apparent dimensionality, d = 1.6. Thus, we conclude that membrane stacking does not affect the efficiency of the delivery of excitation energy toward the reaction centers but ensures a more compact organization of the thylakoid membranes within the chloroplast and separation of photosystems I and II.

  19. Preparation and evaluation of PEGylated phospholipid membrane coated layered double hydroxide nanoparticles

    Directory of Open Access Journals (Sweden)

    Mina Yan

    2016-06-01

    Full Text Available The aim of the present study was to develop layered double hydroxide (LDH nanoparticles coated with PEGylated phospholipid membrane. By comparing the size distribution and zeta potential, the weight ratio of LDH to lipid materials which constitute the outside membrane was identified as 2:1. Transmission electron microscopy photographs confirmed the core-shell structure of PEGylated phospholipid membrane coated LDH (PEG-PLDH nanoparticles, and cell cytotoxicity assay showed their good cell viability on Hela and BALB/C-3T3 cells over the concentration range from 0.5 to 50 μg/mL.

  20. Asymmetric polymeric membranes containing a metal-rich dense layer with a controlled thickness and method of making same

    KAUST Repository

    Peinemann, Klaus-Viktor; Villalobos, Vazquez De La Parra Luis Francisco

    2016-01-01

    A structure, and methods of making the structure are provided in which the structure can include: a membrane having a first layer and a second layer, the first layer comprising polymer chains formed with coordination complexes with metal ions, and the second layer consisting of a porous support layer formed of polymer chains substantially, if not completely, lacking the presence of metal ions. The structure can be an asymmetric polymeric membrane containing a metal-rich layer as the first layer. In various embodiments the first layer can be a metal-rich dense layer. The first layer can include pores. The polymer chains of the first layer can be closely packed. The second layer can include a plurality of macro voids and can have an absence of the metal ions of the first layer.

  1. Asymmetric polymeric membranes containing a metal-rich dense layer with a controlled thickness and method of making same

    KAUST Repository

    Peinemann, Klaus-Viktor

    2016-01-21

    A structure, and methods of making the structure are provided in which the structure can include: a membrane having a first layer and a second layer, the first layer comprising polymer chains formed with coordination complexes with metal ions, and the second layer consisting of a porous support layer formed of polymer chains substantially, if not completely, lacking the presence of metal ions. The structure can be an asymmetric polymeric membrane containing a metal-rich layer as the first layer. In various embodiments the first layer can be a metal-rich dense layer. The first layer can include pores. The polymer chains of the first layer can be closely packed. The second layer can include a plurality of macro voids and can have an absence of the metal ions of the first layer.

  2. Layer-by-layer bioassembly of cellularized polylactic acid porous membranes for bone tissue engineering

    NARCIS (Netherlands)

    Guduric, Vera; Metz, Carole; Siadous, Robin; Bareille, Reine; Levato, Riccardo; Engel, Elisabeth; Fricain, Jean-Christophe; Devillard, Raphaël; Luzanin, Ognjan; Catros, Sylvain

    2017-01-01

    The conventional tissue engineering is based on seeding of macroporous scaffold on its surface ("top-down" approach). The main limitation is poor cell viability in the middle of the scaffold due to poor diffusion of oxygen and nutrients and insufficient vascularization. Layer-by-Layer (LBL)

  3. Apparatus suitable for plasma surface treating and process for preparing membrane layers

    NARCIS (Netherlands)

    1988-01-01

    The invention relates to an apparatus suitable for plasma surface treating (e.g. forming a membrane layer on a substrate) which comprises a plasma generation section (2) which is in communication via at least one plasma inlet means (4) (e.g. a nozzle) with an enclosed plasma treating section (3)

  4. Characterizing free volumes and layer structures in polymeric membranes using slow positron annihilation spectroscopy

    International Nuclear Information System (INIS)

    Jean, Y C; Chen Hongmin; Awad, Somia; Zhang Sui; Chen Hangzheng; Lau, Cher Hon; Wang Huan; Li Fuyun; Chung, Tai-Shung; Lee, L James; Huang, James

    2011-01-01

    Positron annihilation spectroscopy coupled with a newly built slow positron beam at National University of Singapore has been used to study the free volume, pore, and depth profile (0 - 10 μm) in cellulose acetate polymeric membrane at the bottom and top sides of membranes for ionic separation in water purification applications. The S and R parameters from Doppler broadening energy of annihilation radiation representing free volumes (0.1-1 nm size) and pores (>1 nm-μm) as a function of depth have been analyzed into multilayers, i.e. skin dense, transition, and porous layers, respectively. The top side of membrane has large free volumes and pores and the bottom side has a skin dense layer, which plays a key role in membrane performance. Positron annihilation lifetime results provide additional information about free-volume size and distribution at the atomic and molecular scale in polymeric membrane systems. Doppler broadening energy and lifetime spectroscopies coupled with a variable mono-energy slow positron beam are sensitive and novel techniques for characterization of polymeric membrane in separation applications.

  5. Improved antifouling properties of polymer membranes using a ‘layer-by-layer’ mediated method

    KAUST Repository

    Chen, Lin

    2013-01-01

    Polymeric reverse osmosis membranes were modified with antifouling polymer brushes through a \\'layer by layer\\' (LBL) mediated method. Based on pure physical electrostatic interaction, the attachment of LBL films did not alter separation performance of the membranes. In addition, the incorporation of an LBL film also helped to amplify the number of potential reaction sites on the membrane surfaces for attachment of antifouling polymer brushes, which were then attached to the surface. Attachment of the brushes included two different approaches, grafting to and grafting from. Attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS) and water contact angle measurements showed successful growth of the LBL films and subsequently the polymer brushes. Using this method to modify reverse osmosis membranes, preliminary performance testing showed the antifouling properties of the as-modified membranes were much better than the virgin membrane with no significant loss in water flux and salt rejection. © 2013 The Royal Society of Chemistry.

  6. Chlorine-Resistant Polyamide Reverse Osmosis Membrane with Monitorable and Regenerative Sacrificial Layers.

    Science.gov (United States)

    Huang, Hai; Lin, Saisai; Zhang, Lin; Hou, Li'an

    2017-03-22

    Improving chlorine stability is a high priority for aromatic polyamide (PA) reverse osmosis (RO) membranes especially in long-term desalination. In this Research Article, PA RO membranes of sustainable chlorine resistance was synthesized. Glycylglycine (Gly) was grafted onto the membrane surface as a regenerative chlorine sacrificial layer, and the zeta-potential was used to monitor the membrane performance and to conduct timely regeneration operations for chlorinated Gly. The Gly-grafted PA membrane exhibited ameliorative chlorine resistance in which the N-H moiety of glycylglycine served as sacrificial pendants against chlorine attacks. Cyclic chlorination experiments, combined with FT-IR and XPS analysis, were carried out to characterize the membrane. Results indicated that the resulting N-halamines could be fast regenerated by a simple alkaline reduction step (pH 10). A synchronous relationship between the zeta-potential and the chlorination extent of the sacrificial layer was observed. This indicated that the zeta-potential can be used as an on-site sensor to conduct a timely regeneration operation. The intrinsic mechanism of the surface sacrificial process was also studied.

  7. Fabrication and characterization of two-layered nanofibrous membrane for guided bone and tissue regeneration application.

    Science.gov (United States)

    Masoudi Rad, Maryam; Nouri Khorasani, Saied; Ghasemi-Mobarakeh, Laleh; Prabhakaran, Molamma P; Foroughi, Mohammad Reza; Kharaziha, Mahshid; Saadatkish, Niloufar; Ramakrishna, Seeram

    2017-11-01

    Membranes used in dentistry act as a barrier to prevent invasion of intruder cells to defected area and obtains spaces that are to be subsequently filled with new bone and provide required bone volume for implant therapy when there is insufficient volume of healthy bone at implant site. In this study a two-layered bioactive membrane were fabricated by electrospinning whereas one layer provides guided bone regeneration (GBR) and fabricated using poly glycerol sebacate (PGS)/polycaprolactone (PCL) and Beta tri-calcium phosphate (β-TCP) (5, 10 and 15%) and another one containing PCL/PGS and chitosan acts as guided tissue regeneration (GTR). The morphology, chemical, physical and mechanical characterizations of the membranes were studied using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), tensile testing, then biodegradability and bioactivity properties were evaluated. In vitro cell culture study was also carried out to investigate proliferation and mineralization of cells on different membranes. Transmission electron microscope (TEM) and SEM results indicated agglomeration of β-TCP nanoparticles in the structure of nanofibers containing 15% β-TCP. Moreover by addition of β-TCP from 5% to 15%, contact angle decreased due to hydrophilicity of nanoparticles and bioactivity was found to increase. Mechanical properties of the membrane increased by incorporation of 5% and 10% of β-TCP in the structure of nanofibers, while addition of 15% of β-TCP was found to deteriorate mechanical properties of nanofibers. Although the presence of 5% and 10% of nanoparticles in the nanofibers increased proliferation of cells on GBR layer, cell proliferation was observed to decrease by addition of 15% β-TCP in the structure of nanofibers which is likely due to agglomeration of nanoparticles in the nanofiber structure. Our overall results revealed PCL/PGS containing 10% β-TCP could be selected as the optimum GBR membrane

  8. Polymer supported ZIF-8 membranes by conversion of sputtered zinc oxide layers

    KAUST Repository

    Neelakanda, Pradeep; Barankova, Eva; Peinemann, Klaus-Viktor

    2015-01-01

    ZIF-8 composite membranes were synthesized at room temperature from aqueous solution by a double-zinc-source method on polyacrylonitrile (PAN) porous supports. The support was coated with zinc oxide (ZnO) by magnetron sputtering prior to ZIF-8 growth to improve the nucleation as well as the adhesion between the ZIF-8 layer and support. By this method, we were able to grow a continuous, dense, very thin (900 nm) and defect free ZIF-8 layer on a polymeric support. The developed ZIF-8 membranes had a gas permeance of 1.23 x 10-7 mol m-2 sec-1 Pa-1 for hydrogen and a selectivity of 26 for hydrogen/propane gases which is 5 times higher than the Knudsen selectivity. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis were done to characterize the membranes.

  9. Polymer supported ZIF-8 membranes by conversion of sputtered zinc oxide layers

    KAUST Repository

    Neelakanda, Pradeep

    2015-09-05

    ZIF-8 composite membranes were synthesized at room temperature from aqueous solution by a double-zinc-source method on polyacrylonitrile (PAN) porous supports. The support was coated with zinc oxide (ZnO) by magnetron sputtering prior to ZIF-8 growth to improve the nucleation as well as the adhesion between the ZIF-8 layer and support. By this method, we were able to grow a continuous, dense, very thin (900 nm) and defect free ZIF-8 layer on a polymeric support. The developed ZIF-8 membranes had a gas permeance of 1.23 x 10-7 mol m-2 sec-1 Pa-1 for hydrogen and a selectivity of 26 for hydrogen/propane gases which is 5 times higher than the Knudsen selectivity. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis were done to characterize the membranes.

  10. Multifunctional-layered materials for creating membrane-restricted nanodomains and nanoscale imaging

    Energy Technology Data Exchange (ETDEWEB)

    Srinivasan, P., E-mail: prasri@ece.ucsb.edu, E-mail: srinivasan@lifesci.ucsb.edu [Department of Electrical and Computer Engineering, University of California, Santa Barbara, California 93106, USA and Neuroscience Research Institute, University of California, Santa Barbara, California 93106 (United States)

    2016-01-18

    Experimental platform that allows precise spatial positioning of biomolecules with an exquisite control at nanometer length scales is a valuable tool to study the molecular mechanisms of membrane bound signaling. Using micromachined thin film gold (Au) in layered architecture, it is possible to add both optical and biochemical functionalities in in vitro. Towards this goal, here, I show that docking of complementary DNA tethered giant phospholiposomes on Au surface can create membrane-restricted nanodomains. These nanodomains are critical features to dissect molecular choreography of membrane signaling complexes. The excited surface plasmon resonance modes of Au allow label-free imaging at diffraction-limited resolution of stably docked DNA tethered phospholiposomes, and lipid-detergent bicelle structures. Such multifunctional building block enables realizing rigorously controlled in vitro set-up to model membrane anchored biological signaling, besides serving as an optical tool for nanoscale imaging.

  11. Numerical modeling of solute transport in deformable unsaturated layered soil

    Directory of Open Access Journals (Sweden)

    Sheng Wu

    2017-07-01

    Full Text Available The effect of soil stratification was studied through numerical investigation based on the coupled model of solute transport in deformable unsaturated soil. The theoretical model implied two-way coupled excess pore pressure and soil deformation based on Biot's consolidation theory as well as a one-way coupled volatile pollutant concentration field developed from the advection-diffusion theory. Embedded in the model, the degree of saturation, fluid compressibility, self-weight of the soil matrix, porosity variance, longitudinal dispersion, and linear sorption were computed. Based on simulation results of a proposed three-layer landfill model using the finite element method, the multi-layer effects are discussed with regard to the hydraulic conductivity, shear modulus, degree of saturation, molecular diffusion coefficient, and thickness of each layer. Generally speaking, contaminants spread faster in a stratified field with a soft and highly permeable top layer; soil parameters of the top layer are more critical than the lower layers but controlling soil thicknesses will alter the results. This numerical investigation showed noticeable impacts of stratified soil properties on solute migration results, demonstrating the importance of correctly modeling layered soil instead of simply assuming the averaged properties across the soil profile.

  12. Anti-fouling and high water permeable forward osmosis membrane fabricated via layer by layer assembly of chitosan/graphene oxide

    Science.gov (United States)

    Salehi, Hasan; Rastgar, Masoud; Shakeri, Alireza

    2017-08-01

    To date, forward osmosis (FO) has received considerable attention due to its potential application in seawater desalination. FO does not require external hydraulic pressure and consequently is believed to have a low fouling propensity. Despite the numerous privileges of FO process, a major challenge ahead for its development is the lack of high performance membranes. In this study, we fabricated a novel highly-efficient FO membrane using layer-by-layer (LbL) assembly of positive chitosan (CS) and negative graphene oxide (GO) nanosheets via electrostatic interaction on a porous support layer. The support layer was prepared by blending hydrophilic sulfonated polyethersulfone (SPES) into polyethersulfone (PES) matrix using wet phase inversion process. Various characterization techniques were used to confirm successful fabrication of LbL membrane. The number of layers formed on the SPES-PES support layer was easily adjusted by repeating the CS and GO deposition cycles. Thin film composite (TFC) membrane was also prepared by the same SPES-PES support layer and polyamide (PA) active layer to compare membranes performances. The water permeability and salt rejection of the fabricated membranes were obtained by two kinds of draw solutions (including Na2SO4 and sucrose) under two different membrane orientations. The results showed that membrane coated by a CS/GO bilayers had water flux of 2-4 orders of magnitude higher than the TFC one. By increasing the number of CS/GO bilayers, the selectivity of the LbL membrane was improved. The novel fabricated LbL membrane showed better fouling resistance than the TFC one in the feed solution containing 200 ppm of sodium alginate as a foulant model.

  13. Layer-by-layer assembly of graphene oxide on polypropylene macroporous membranes via click chemistry to improve antibacterial and antifouling performance

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Zhen-Bei, E-mail: 1021453457@qq.com [The Key Laboratory of Functional Molecular Solids, Ministry of Education, Anhui Key Laboratory of Molecular-Based Materials, College of Chemistry and Materials Science, Anhui Normal University, East Beijing Rd. 1, Wuhu, Anhui 241000 (China); Wu, Jing-Jing, E-mail: 957522275@qq.com [The Key Laboratory of Functional Molecular Solids, Ministry of Education, Anhui Key Laboratory of Molecular-Based Materials, College of Chemistry and Materials Science, Anhui Normal University, East Beijing Rd. 1, Wuhu, Anhui 241000 (China); Su, Yu, E-mail: 819388710@qq.com [The Key Laboratory of Functional Molecular Solids, Ministry of Education, Anhui Key Laboratory of Molecular-Based Materials, College of Chemistry and Materials Science, Anhui Normal University, East Beijing Rd. 1, Wuhu, Anhui 241000 (China); Zhou, Jin, E-mail: zhoujin_ah@163.com [Department of Materials and Chemical Engineering, Chizhou University, Muzhi Rd. 199, Chizhou, Anhui 247000 (China); Gao, Yong, E-mail: 154682180@qq.com [School of Chemistry and Environmental Engineering, Jiangsu University of Technology, Changzhou 213001 (China); Yu, Hai-Yin, E-mail: yhy456@mail.ahnu.edu.cn [The Key Laboratory of Functional Molecular Solids, Ministry of Education, Anhui Key Laboratory of Molecular-Based Materials, College of Chemistry and Materials Science, Anhui Normal University, East Beijing Rd. 1, Wuhu, Anhui 241000 (China); Gu, Jia-Shan, E-mail: jiashanG@mail.ahnu.edu.cn [The Key Laboratory of Functional Molecular Solids, Ministry of Education, Anhui Key Laboratory of Molecular-Based Materials, College of Chemistry and Materials Science, Anhui Normal University, East Beijing Rd. 1, Wuhu, Anhui 241000 (China)

    2015-03-30

    Graphical abstract: - Highlights: • Clickable membrane prepared by photo bromination and S{sub N}2 nucleophilic substitution. • Azide graphene oxide prepared by ring-opening reaction. • Alkyne graphene oxide was prepared via esterification reaction. • Layer-by-layer assembly of graphene oxide on membrane by click chemistry. • Antibacterial and antifouling characteristics were enhanced greatly. - Abstract: Polypropylene is an extensively used membrane material; yet, polypropylene membranes exhibit extremely poor resistance to protein fouling. To ameliorate this issue, graphene oxide (GO) nanosheets were used to modify macroporous polypropylene membrane (MPPM) via layer-by-layer assembly technique through click reaction. First, alkyne-terminated GO was prepared through esterification between carboxyl groups in GO and amide groups in propargylamine; azide-terminated GO was synthesized by the ring-opening reaction of epoxy groups in GO with sodium azide. Second, GO was introduced to the membrane by click chemistry. Characterizations of infrared spectra and X-ray photoelectron spectroscopy confirmed the modification. The sharply decreasing of static water contact angle indicated the improvement of the surface hydrophilicity for GO modified membrane. Introducing GO to the membrane results in a dramatic increase of water flux, improvements in the antifouling characteristics and antibacterial property for the membranes. The pure water flux through the 5-layered GO modified membrane is 1.82 times that through the unmodified one. The water flux restores to 43.0% for the unmodified membrane while to 79.8% for the modified membrane. The relative flux reduction decreases by 32.1% due to GO modification. The antibacterial property was also enhanced by two-thirds. These results demonstrate that the antifouling and antibacterial characteristics can be raised by tethering GO to the membrane surface.

  14. Layer-by-layer assembly of graphene oxide on polypropylene macroporous membranes via click chemistry to improve antibacterial and antifouling performance

    International Nuclear Information System (INIS)

    Zhang, Zhen-Bei; Wu, Jing-Jing; Su, Yu; Zhou, Jin; Gao, Yong; Yu, Hai-Yin; Gu, Jia-Shan

    2015-01-01

    Graphical abstract: - Highlights: • Clickable membrane prepared by photo bromination and S N 2 nucleophilic substitution. • Azide graphene oxide prepared by ring-opening reaction. • Alkyne graphene oxide was prepared via esterification reaction. • Layer-by-layer assembly of graphene oxide on membrane by click chemistry. • Antibacterial and antifouling characteristics were enhanced greatly. - Abstract: Polypropylene is an extensively used membrane material; yet, polypropylene membranes exhibit extremely poor resistance to protein fouling. To ameliorate this issue, graphene oxide (GO) nanosheets were used to modify macroporous polypropylene membrane (MPPM) via layer-by-layer assembly technique through click reaction. First, alkyne-terminated GO was prepared through esterification between carboxyl groups in GO and amide groups in propargylamine; azide-terminated GO was synthesized by the ring-opening reaction of epoxy groups in GO with sodium azide. Second, GO was introduced to the membrane by click chemistry. Characterizations of infrared spectra and X-ray photoelectron spectroscopy confirmed the modification. The sharply decreasing of static water contact angle indicated the improvement of the surface hydrophilicity for GO modified membrane. Introducing GO to the membrane results in a dramatic increase of water flux, improvements in the antifouling characteristics and antibacterial property for the membranes. The pure water flux through the 5-layered GO modified membrane is 1.82 times that through the unmodified one. The water flux restores to 43.0% for the unmodified membrane while to 79.8% for the modified membrane. The relative flux reduction decreases by 32.1% due to GO modification. The antibacterial property was also enhanced by two-thirds. These results demonstrate that the antifouling and antibacterial characteristics can be raised by tethering GO to the membrane surface

  15. Influence of Active Layer on Separation Potentials of Nanofiltration Membranes for Inorganic Ions.

    Science.gov (United States)

    Wadekar, Shardul S; Vidic, Radisav D

    2017-05-16

    Active layers of two fully aromatic and two semi-aromatic nanofiltration membranes were studied along with surface charge at different electrolyte composition and effective pore size to elucidate their influence on separation mechanisms for inorganic ions by steric, charge, and dielectric exclusion. The membrane potential method used for pore size measurement is underlined as the most appropriate measurement technique for this application owing to its dependence on the diffusional potentials of inorganic ions. Crossflow rejection experiments with dilute feed composition indicate that both fully aromatic membranes achieved similar rejection despite the differences in surface charge, which suggests that rejection by these membranes is exclusively dependent on size exclusion and the contribution of charge exclusion is weak. Rejection experiments with higher ionic strength and different composition of the feed solution confirmed this hypothesis. On the other hand, increase in the ionic strength of feed solution when the charge exclusion effects are negligible due to charge screening strongly influenced ion rejection by semi-aromatic membranes. The experimental results confirmed that charge exclusion contributes significantly to the performance of semi-aromatic membranes in addition to size exclusion. The contribution of dielectric exclusion to overall ion rejection would be more significant for fully aromatic membranes.

  16. Parenteral immunization of PLA/PLGA nanoparticle encapsulating outer membrane protein (Omp) from Aeromonas hydrophila: Evaluation of immunostimulatory action in Labeo rohita (rohu).

    Science.gov (United States)

    Rauta, Pradipta Ranjan; Nayak, Bismita

    2015-05-01

    Advanced vaccine research approaches needs to explore on biodegradable nanoparticles (NPs) based vaccine carrier that can serve as antigen delivery systems as well as immuno-stimulatory action to induce both innate and adaptive immune response in fish. Immunogenicity of PLA and PLGA NPs encapsulating outer membrane protein (Omp) antigen of Aeromonas hydrophila were evaluated through intra-peritoneal injection in fish, Labeo rohita. Antigen loaded PLA-Omp (223.5 ± 13.19 nm) and PLGA-Omp (166.4 ± 21.23 nm) NPs were prepared using double emulsion method by efficiently encapsulating the antigen reaching the encapsulation efficiency 44 ± 4.58% and 59.33 ± 5.13% respectively. Our formulated PLA Omp and PLGA-Omp NPs were in nanometer range (PLA-Omp, it showed considerably slower antigen release in vitro than PLGA-Omp NPs. Other physical properties like zetapotential values and poly dispersity index (PDI) confirmed the stability as well as monodisperse nature of the formulated nanoparticles. The spherical and isolated nature of PLA-Omp and PLGA-Omp NPs were revealed by SEM analysis. Upon immunization of all antigenic formulations (PLA-Omp NP, PLGA-Omp NP, FIA-Omp, PLA NP, PLGA NP, PBS as control), significant higher bacterial agglutination titre and haemolytic activity were observed in case of PLA-Omp and PLGA-Omp immunized groups than rest groups at both 21 days and 42 days. The specific antibody response was significantly increased and persisted up to 42 days of post immunization by PLA-Omp, PLGA-Omp, FIA-Omp. PLA-Omp NPs showed better immune response (higher bacterial agglutination titre, haemolytic activity, specific antibody titre, higher percent survival upon A. hydrophila challenge) than PLGA-Omp in L. rohita confirming its better efficacy. Comparable antibody response of PLA-Omp and PLGA-Omp with FIA-Omp treated groups suggested that PLA and PLGA could be replacement for Freund's adjuvant (for stimulating antibody response) to overcome many side effects

  17. Prediction of unsaturated flow and water backfill during infiltration in layered soils

    Science.gov (United States)

    Cui, Guotao; Zhu, Jianting

    2018-02-01

    We develop a new analytical infiltration model to determine water flow dynamics around layer interfaces during infiltration process in layered soils. The model mainly involves the analytical solutions to quadratic equations to determine the flux rates around the interfaces. Active water content profile behind the wetting front is developed based on the solution of steady state flow to dynamically update active parameters in sharp wetting front infiltration equations and to predict unsaturated flow in coarse layers before the front reaches an impeding fine layer. The effect of water backfill to saturate the coarse layers after the wetting front encounters the impeding fine layer is analytically expressed based on the active water content profiles. Comparison to the numerical solutions of the Richards equation shows that the new model can well capture water dynamics in relation to the arrangement of soil layers. The steady state active water content profile can be used to predict the saturation state of all layers when the wetting front first passes through these layers during the unsteady infiltration process. Water backfill effect may occur when the unsaturated wetting front encounters a fine layer underlying a coarse layer. Sensitivity analysis shows that saturated hydraulic conductivity is the parameter dictating the occurrence of unsaturated flow and water backfill and can be used to represent the coarseness of soil layers. Water backfill effect occurs in coarse layers between upper and lower fine layers when the lower layer is not significantly coarser than the upper layer.

  18. Unravelling Light-Induced Degradation of Layered Perovskite Crystals and Design of Efficient Encapsulation for Improved Photostability

    NARCIS (Netherlands)

    Fang, Hong-Hua; Yang, Jie; Tao, Shuxia; Adjokatse, Sampson; Kamminga, Machteld E.; Ye, Jianting; Blake, Graeme; Even, Jacky; Loi, Maria Antoinetta

    2018-01-01

    Layered halide perovskites have recently shown extraordinary potential for low‐cost solution‐processable optoelectronic applications because of their superior moisture stability over their 3D counterparts. However, few studies have investigated the effect of light on layered hybrid perovskites.

  19. Morphological evolution of carbon nanofibers encapsulating SnCo alloys and its effect on growth of the solid electrolyte interphase layer.

    Science.gov (United States)

    Shin, Jungwoo; Ryu, Won-Hee; Park, Kyu-Sung; Kim, Il-Doo

    2013-08-27

    Two distinctive one-dimensional (1-D) carbon nanofibers (CNFs) encapsulating irregularly and homogeneously segregated SnCo nanoparticles were synthesized via electrospinning of polyvinylpyrrolidone (PVP) and polyacrylonitrile (PAN) polymers containing Sn-Co acetate precursors and subsequent calcination in reducing atmosphere. CNFs synthesized with PVP, which undergoes structural degradation of the polymer during carbonization processes, exhibited irregular segregation of heterogeneous alloy particles composed of SnCo, Co3Sn2, and SnO with a size distribution of 30-100 nm. Large and exposed multiphase SnCo particles in PVP-driven amorphous CNFs (SnCo/PVP-CNFs) kept decomposing liquid electrolyte and were partly detached from CNFs during cycling, leading to a capacity fading at the earlier cycles. The closer study of solid electrolyte interphase (SEI) layers formed on the CNFs reveals that the gradual growth of fiber radius due to continuous increment of SEI layer thickness led to capacity fading. In contrast, SnCo particles in PAN-driven CNFs (SnCo/PAN-CNFs) showed dramatically reduced crystallite sizes (<10 nm) of single phase SnCo nanoparticles which were entirely embedded in dense, semicrystalline, and highly conducting 1-D carbon matrix. The growth of SEI layer was limited and saturated during cycling. As a result, SnCo/PAN-CNFs showed much improved cyclability (97.9% capacity retention) and lower SEI layer thickness (86 nm) after 100 cycles compared to SnCo/PVP-CNFs (capacity retention, 71.9%; SEI layer thickness, 593 nm). This work verifies that the thermal behavior of carbon precursor is highly responsible for the growth mechanism of SEI layer accompanied with particles detachment and cyclability of alloy particle embedded CNFs.

  20. The evaluation method of soil-spring for the analyses of foundation structures on layered bedsoil

    International Nuclear Information System (INIS)

    Satoh, S.; Sasaki, F.

    1985-01-01

    When performing the finite element method analysis of foundation structures, such as mat slab of reactor buildings and turbine buildings, it is very important to evaluate and model the soil-spring mechanism between foundation and soil correctly. In this model, this paper presents the method in which soil-spring mechanism is evaluated from the theoretical solution. In this theory the semi-infinite elastic solid is assumed to be made of multi-layered soil systems. From the analytical example, it is concluded that the stress analysis of foundation structures on multi-layered soil systems cannot be evaluated by the conventional methods. (orig.)

  1. Sorption and movement of pesticides on thin layer plates of Brazilain soils

    International Nuclear Information System (INIS)

    Lord, K.A.; Helene, C.G.; Andrea, M.M. de; Ruegg, E.F.

    1979-01-01

    The sorption from aqueous solution, and movement in water on thin layers plates of 7 soils of 3 organochlorine, 2 organophosphorus and 1 carbamate insecticide was determined in the laboratory. Generally, all substances were sorbed most and moved least on soils richest in organic matter. However, sorption was not a function of organic matter content alone. Aldrin and DDT were most strongly sorbed and did not move from the point of application on the thin layer plates of any soil. On all 7 soils, carbaryl was the least strongly sorbed insecticide. On 5 soils, lindane, parathion and malathion were increasingly strongly sorbed, but on the other 2 soils lindane was mostly strongly sorbed. The apparent greater mobility of 14 C-labelled malathion on thin layers of soils repeatedly leached could be explained by the formation of more polar substances. (author) [pt

  2. The study of stress-strain state of stabilized layered soil foundations

    Directory of Open Access Journals (Sweden)

    Sokolov Mikhail V.

    2017-01-01

    Full Text Available Herein presented are the results of modeling and analysis of stress-strain state of layered inhomogeneous foundation soil when it is stabilised by injection to different depths. Produced qualitative and quantitative analysis of the components of the field of isolines of stresses, strains, stress concentration and the difference between the strain at the boundary of different elastic horizontal layers. Recommendations are given for the location of stabilised zones in relation to the border of different elastic layers. In particular, it found that stabilization of soil within the weak layer is inappropriate, since it practically provides no increase in the stability of the soil foundation, and when performing stabilisation of soil foundations, it is recommended to place the lower border of the stabilisation zone below the border of a stronger layer, at this the distribution of stresses and strains occurs more evenly, and load-bearing capacity of this layer is used to the maximum.

  3. Irreversible fouling of membrane bioreactors due to formation of a non-biofilm gel-like layer

    DEFF Research Database (Denmark)

    Poorasgari, Eskandar; Larsen, Poul; Zheng, Xing

    2013-01-01

    Extra-cellular polymeric substances (EPS), known to contribute to fouling in membrane bio-reactors (MBR)s, are generally divided into bound and free EPS. The free EPS are able to form a gel-like layer on the membrane active surface. The mechanisms involved in formation of such layer and its effects...... on performance of the MBR membranes were studied. The free EPS, extracted by centrifugation and microfiltration, contained a significant amount of humic-like substances. Under static contact to the membrane, adsorption of humic-like substances to the membrane occurred and could be explained by conventional...... adsorption kinetics. Due to static adsorption, surface roughness of the membrane declined significantly indicating that adsorbed matters to the membrane filled the cavities of the membrane surface. Filtration of the free EPS caused 50% water flux decline. The fouling resistance linearly increased...

  4. Interaction of S-layer proteins of Lactobacillus kefir with model membranes and cells.

    Science.gov (United States)

    Hollmann, Axel; Delfederico, Lucrecia; Santos, Nuno C; Disalvo, E Anibal; Semorile, Liliana

    2018-06-01

    In previous works, it was shown that S-layer proteins from Lactobacillus kefir were able to recrystallize and stabilize liposomes, this feature reveling a great potential for developing liposomal-based carriers. Despite previous studies on this subject are important milestones, a number of questions remain unanswered. In this context, the feasibility of S-layer proteins as a biomaterial for drug delivery was evaluated in this work. First, S-layer proteins were fully characterized by electron microscopy, 2D-electrophoresis, and anionic exchange chromatography coupled with pulsed amperometric detection (HPAEC-PAD). Afterward, interactions of S-layer proteins with model lipid membranes were evaluated, showing that proteins adsorb to the lipid surface following a non-fickean or anomalous diffusion, when positively charged lipid were employed, suggesting that electrostatic interaction is a key factor in the recrystallization process on these proteins. Finally, the interaction of S-layer coated liposomes with Caco-2 cell line was assessed: First, cytotoxicity of formulations was tested showing no cytotoxic effects in S-layer coated vesicles. Second, by flow cytometry, it was observed an increased ability to transfer cargo molecules into Caco-2 cells from S-layer coated liposomes in comparison to control ones. All data put together, supports the idea that a combination of adhesive properties of S-layer proteins concomitant with higher stability of S-layer coated liposomes represents an exciting starting point in the development of new drug carriers.

  5. Tomographic Structural Changes of Retinal Layers after Internal Limiting Membrane Peeling for Macular Hole Surgery.

    Science.gov (United States)

    Faria, Mun Yueh; Ferreira, Nuno P; Cristóvao, Diana M; Mano, Sofia; Sousa, David Cordeiro; Monteiro-Grillo, Manuel

    2018-01-01

    To highlight tomographic structural changes of retinal layers after internal limiting membrane (ILM) peeling in macular hole surgery. Nonrandomized prospective, interventional study in 38 eyes (34 patients) subjected to pars plana vitrectomy and ILM peeling for idiopathic macular hole. Retinal layers were assessed in nasal and temporal regions before and 6 months after surgery using spectral domain optical coherence tomography. Total retinal thickness increased in the nasal region and decreased in the temporal region. The retinal nerve fiber layer (RNFL), ganglion cell layer (GCL), and inner plexiform layer (IPL) showed thinning on both nasal and temporal sides of the fovea. The thickness of the outer plexiform layer (OPL) increased. The outer nuclear layer (ONL) and outer retinal layers (ORL) increased in thickness after surgery in both nasal and temporal regions. ILM peeling is associated with important alterations in the inner retinal layer architecture, with thinning of the RNFL-GCL-IPL complex and thickening of OPL, ONL, and ORL. These structural alterations can help explain functional outcome and could give indications regarding the extent of ILM peeling, even though peeling seems important for higher rate of hole closure. © 2017 S. Karger AG, Basel.

  6. Well-constructed cellulose acetate membranes for forward osmosis: Minimized internal concentration polarization with an ultra-thin selective layer

    KAUST Repository

    Zhang, Sui

    2010-09-01

    The design and engineering of membrane structure that produces low salt leakage and minimized internal concentration polarization (ICP) in forward osmosis (FO) processes have been explored in this work. The fundamentals of phase inversion of cellulose acetate (CA) regarding the formation of an ultra-thin selective layer at the bottom interface of polymer and casting substrate were investigated by using substrates with different hydrophilicity. An in-depth understanding of membrane structure and pore size distribution has been elucidated with field emission scanning electronic microscopy (FESEM) and positron annihilation spectroscopy (PAS). A double dense-layer structure is formed when glass plate is used as the casting substrate and water as the coagulant. The thickness of the ultra-thin bottom layer resulted from hydrophilic-hydrophilic interaction is identified to be around 95nm, while a fully porous, open-cell structure is formed in the middle support layer due to spinodal decomposition. Consequently, the membrane shows low salt leakage with mitigated ICP in the FO process for seawater desalination. The structural parameter (St) of the membrane is analyzed by modeling water flux using the theory that considers both external concentration polarization (ECP) and ICP, and the St value of the double dense-layer membrane is much smaller than those reported in literatures. Furthermore, the effects of an intermediate immersion into a solvent/water mixed bath prior to complete immersion in water on membrane formation have been studied. The resultant membranes may have a single dense layer with an even lower St value. A comparison of fouling behavior in a simple FO-membrane bioreactor (MBR) system is evaluated for these two types of membranes. The double dense-layer membrane shows a less fouling propensity. This study may help pave the way to improve the membrane design for new-generation FO membranes. © 2010 Elsevier B.V.

  7. Catalytic, Conductive Bipolar Membrane Interfaces through Layer-by-Layer Deposition for the Design of Membrane-Integrated Artificial Photosynthesis Systems.

    Science.gov (United States)

    McDonald, Michael B; Freund, Michael S; Hammond, Paula T

    2017-11-23

    In the presence of an electric field, bipolar membranes (BPMs) are capable of initiating water disassociation (WD) within the interfacial region, which can make water splitting for renewable energy in the presence of a pH gradient possible. In addition to WD catalytic efficiency, there is also the need for electronic conductivity in this region for membrane-integrated artificial photosynthesis (AP) systems. Graphene oxide (GO) was shown to catalyze WD and to be controllably reduced, which resulted in electronic conductivity. Layer-by-layer (LbL) film deposition was employed to improve GO film uniformity in the interfacial region to enhance WD catalysis and, through the addition of a conducting polymer in the process, add electronic conductivity in a hybrid film. Three different deposition methods were tested to optimize conducting polymer synthesis with the oxidant in a metastable solution and to yield the best film properties. It was found that an approach that included substrate dipping in a solution containing the expected final monomer/oxidant ratio provided the most predictable film growth and smoothest films (by UV/Vis spectroscopy and atomic force microscopy/scanning electron microscopy, respectively), whereas dipping in excess oxidant or co-spraying the oxidant and monomer produced heterogeneous films. Optimized films were found to be electronically conductive and produced a membrane ohmic drop that was acceptable for AP applications. Films were integrated into the interfacial region of BPMs and revealed superior WD efficiency (≥1.4 V at 10 mA cm -2 ) for thinner films (<10 bilayers≈100 nm) than for either the pure GO catalyst or conducting polymer individually, which indicated that there was a synergistic effect between these materials in the structure configured by the LbL method. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Thin-film Nanofibrous Composite Membranes Containing Cellulose or Chitin Barrier Layers Fabricated by Ionic Liquids

    Energy Technology Data Exchange (ETDEWEB)

    H Ma; B Hsiao; B Chu

    2011-12-31

    The barrier layer of high-flux ultrafiltration (UF) thin-film nanofibrous composite (TFNC) membranes for purification of wastewater (e.g., bilge water) have been prepared by using cellulose, chitin, and a cellulose-chitin blend, regenerated from an ionic liquid. The structures and properties of regenerated cellulose, chitin, and a cellulose-chitin blend were analyzed with thermogravimetric analysis (TGA) and wide-angle X-ray diffraction (WAXD). The surface morphology, pore size and pore size distribution of TFNC membranes were determined by SEM images and molecular weight cut-off (MWCO) methods. An oil/water emulsion, a model of bilge water, was used as the feed solution, and the permeation flux and rejection ratio of the membranes were investigated. TFNC membranes based on the cellulose-chitin blend exhibited 10 times higher permeation flux when compared with a commercial UF membrane (PAN10, Sepro) with a similar rejection ratio after filtration over a time period of up to 100 h, implying the practical feasibility of such membranes for UF applications.

  9. Analyte-triggered luminescence of Eu{sup 3+} ions encapsulated in Nafion membranes -preparation of hybrid materials from in membrane chemical reactions-

    Energy Technology Data Exchange (ETDEWEB)

    Aguilar-Sánchez, Rocío, E-mail: raguilar@ifuap.buap.mx [Depto. Química Analítica, Facultad de Ciencias Químicas, Benemérita Universidad Autónoma de Puebla, Puebla 72570 (Mexico); Zelocualtecatl-Montiel, Iván [Depto. Química Analítica, Facultad de Ciencias Químicas, Benemérita Universidad Autónoma de Puebla, Puebla 72570 (Mexico); Gálvez-Vázquez, María de Jesús [Depto. Química Analítica, Facultad de Ciencias Químicas, Benemérita Universidad Autónoma de Puebla, Puebla 72570 (Mexico); Instituto de Física, Benemérita Universidad Autónoma de Puebla, Apartado postal J-48, Puebla 72570 (Mexico); Silva-González, Rutilo [Instituto de Física, Benemérita Universidad Autónoma de Puebla, Apartado postal J-48, Puebla 72570 (Mexico)

    2017-04-15

    The possibility to perform chemical reactions inside polymer materials opens a unique opportunity to control and prepare materials for diverse solid-state applications. Based on the affinity of Eu{sup 3+} ions for oxygen functionalities, in this work we report the luminescence enhancement of Eu{sup 3+} ions inserted in Nafion membranes (Naf/Eu{sup 3+}) by in-situ complexing to oxalate. The formation of a europium-oxalate type complex enhances Eu{sup 3+} luminescence emission, which could be exploited for the construction of devices for oxalate sensing and the fabrication of highly luminescent materials. Possible analytical applications of Naf/Eu{sup 3+} membranes were evaluated by fluorescence spectroscopy through the linear response with concentration. The complex formation was followed by infrared spectroscopy and SEM-EDS analysis. - Highlights: • Luminescence enhancement by complexation of Eu{sup 3+} ions to oxalate inside Nafion. • Performance of chemical reactions inside Nafion/polymer membranes. • An easy and novel method to prepare luminescent solid devices. • Possibility to develop luminescent sensors by analyte-triggered optical response.

  10. Instabilities and diffusion in a hydrodynamic model of a fluid membrane coupled to a thin active fluid layer.

    Science.gov (United States)

    Sarkar, N; Basu, A

    2012-11-01

    We construct a coarse-grained effective two-dimensional (2d hydrodynamic theory as a theoretical model for a coupled system of a fluid membrane and a thin layer of a polar active fluid in its ordered state that is anchored to the membrane. We show that such a system is prone to generic instabilities through the interplay of nonequilibrium drive, polar order and membrane fluctuation. We use our model equations to calculate diffusion coefficients of an inclusion in the membrane and show that their values depend strongly on the system size, in contrast to their equilibrium values. Our work extends the work of S. Sankararaman and S. Ramaswamy (Phys. Rev. Lett., 102, 118107 (2009)) to a coupled system of a fluid membrane and an ordered active fluid layer. Our model is broadly inspired by and should be useful as a starting point for theoretical descriptions of the coupled dynamics of a cell membrane and a cortical actin layer anchored to it.

  11. Engineering the mechanical properties of ultrabarrier films grown by atomic layer deposition for the encapsulation of printed electronics

    International Nuclear Information System (INIS)

    Bulusu, A.; Singh, A.; Kim, H.; Wang, C. Y.; Dindar, A.; Fuentes-Hernandez, C.; Kippelen, B.; Cullen, D.; Graham, S.

    2015-01-01

    Direct deposition of barrier films by atomic layer deposition (ALD) onto printed electronics presents a promising method for packaging devices. Films made by ALD have been shown to possess desired ultrabarrier properties, but face challenges when directly grown onto surfaces with varying composition and topography. Challenges include differing nucleation and growth rates across the surface, stress concentrations from topography and coefficient of thermal expansion mismatch, elastic constant mismatch, and particle contamination that may impact the performance of the ALD barrier. In such cases, a polymer smoothing layer may be needed to coat the surface prior to ALD barrier film deposition. We present the impact of architecture on the performance of aluminum oxide (Al 2 O 3 )/hafnium oxide (HfO 2 ) ALD nanolaminate barrier films deposited on fluorinated polymer layer using an optical calcium (Ca) test under damp heat. It is found that with increasing polymer thickness, the barrier films with residual tensile stress are prone to cracking resulting in rapid failure of the Ca sensor at 50 °C/85% relative humidity. Inserting a SiN x layer with residual compressive stress between the polymer and ALD layers is found to prevent cracking over a range of polymer thicknesses with more than 95% of the Ca sensor remaining after 500 h of testing. These results suggest that controlling mechanical properties and film architecture play an important role in the performance of direct deposited ALD barriers

  12. Engineering the mechanical properties of ultrabarrier films grown by atomic layer deposition for the encapsulation of printed electronics

    Energy Technology Data Exchange (ETDEWEB)

    Bulusu, A.; Singh, A.; Kim, H. [Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States); Wang, C. Y.; Dindar, A.; Fuentes-Hernandez, C.; Kippelen, B. [School of Electrical and Computer Engineering, Georgia Institute of Technology, and Center for Organic Photonics and Electronics, Atlanta, Georgia 30332 (United States); Cullen, D. [Oak Ridge National Laboratory, P.O. Box 2008 MS-6064, Oak Ridge, Tennessee 37831 (United States); Graham, S., E-mail: sgraham@gatech.edu [Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States); Oak Ridge National Laboratory, P.O. Box 2008 MS-6064, Oak Ridge, Tennessee 37831 (United States)

    2015-08-28

    Direct deposition of barrier films by atomic layer deposition (ALD) onto printed electronics presents a promising method for packaging devices. Films made by ALD have been shown to possess desired ultrabarrier properties, but face challenges when directly grown onto surfaces with varying composition and topography. Challenges include differing nucleation and growth rates across the surface, stress concentrations from topography and coefficient of thermal expansion mismatch, elastic constant mismatch, and particle contamination that may impact the performance of the ALD barrier. In such cases, a polymer smoothing layer may be needed to coat the surface prior to ALD barrier film deposition. We present the impact of architecture on the performance of aluminum oxide (Al{sub 2}O{sub 3})/hafnium oxide (HfO{sub 2}) ALD nanolaminate barrier films deposited on fluorinated polymer layer using an optical calcium (Ca) test under damp heat. It is found that with increasing polymer thickness, the barrier films with residual tensile stress are prone to cracking resulting in rapid failure of the Ca sensor at 50 °C/85% relative humidity. Inserting a SiN{sub x} layer with residual compressive stress between the polymer and ALD layers is found to prevent cracking over a range of polymer thicknesses with more than 95% of the Ca sensor remaining after 500 h of testing. These results suggest that controlling mechanical properties and film architecture play an important role in the performance of direct deposited ALD barriers.

  13. Enhancing the platinum atomic layer deposition infiltration depth inside anodic alumina nanoporous membrane

    Energy Technology Data Exchange (ETDEWEB)

    Vaish, Amit, E-mail: anv@udel.edu; Krueger, Susan; Dimitriou, Michael; Majkrzak, Charles [National Institute of Standards and Technology (NIST) Center for Neutron Research, Gaithersburg, MD 20899-8313 (United States); Vanderah, David J. [Institute for Bioscience and Biotechnology Research, NIST, Rockville, Maryland 20850 (United States); Chen, Lei, E-mail: lei.chen@nist.gov [NIST Center for Nanoscale Science and Technology, Gaithersburg, Maryland 20899-8313 (United States); Gawrisch, Klaus [Laboratory of Membrane Biochemistry and Biophysics, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland 20892 (United States)

    2015-01-15

    Nanoporous platinum membranes can be straightforwardly fabricated by forming a Pt coating inside the nanopores of anodic alumina membranes (AAO) using atomic layer deposition (ALD). However, the high-aspect-ratio of AAO makes Pt ALD very challenging. By tuning the process deposition temperature and precursor exposure time, enhanced infiltration depth along with conformal coating was achieved for Pt ALD inside the AAO templates. Cross-sectional scanning electron microscopy/energy dispersive x-ray spectroscopy and small angle neutron scattering were employed to analyze the Pt coverage and thickness inside the AAO nanopores. Additionally, one application of platinum-coated membrane was demonstrated by creating a high-density protein-functionalized interface.

  14. Sulfonated poly(ether ether ketone) membranes for electric double layer capacitors

    International Nuclear Information System (INIS)

    Kim, Wan Ju; Kim, Dong-Won

    2008-01-01

    Sulfonated poly(ether ether ketone) (S-PEEK) with different degree of sulfonation (DS) has been prepared and evaluated as a proton conducting membrane for electric double layer capacitor (EDLC). The polymer electrolytes prepared with S-PEEK membrane exhibited ionic conductivities about 1.2 x 10 -3 -4.5 x 10 -3 S cm -1 at room temperature, which depended on both soaking solvent and degree of sulfonation. The quasi-solid-state EDLCs consisted of activated carbon electrodes and S-PEEK membrane were assembled, and their electrochemical characteristics were studied by cyclic voltammetry and charge-discharge cycle tests. The effect of DS on the electrochemical performances of EDLCs has been investigated

  15. Polyurethane Membranes Modified with Isopropyl Myristate as a Potential Candidate for Encapsulating Electronic Implants: A Study of Biocompatibility and Water Permeability

    Directory of Open Access Journals (Sweden)

    Deepen Paul

    2010-07-01

    Full Text Available Medical polyurethanes have shown good bio-stability and mechanical properties and have been used as coating for implantable medical devices. However, despite their excellent properties, they are relatively permeable to liquid water and water vapour which is a drawback for electronic implant encapsulation. In this study polyether polyurethanes with different soft segment molecular weights were modified by incorporating isopropyl myristate (IPM, as a hydrophobic modifying agent, and the effect of IPM on water resistant and biocompatibility of membranes were investigated. IPM changed the surface properties of the polyurethane film and reduced its surface energy. Polyurethane films were found to be stable with IPM concentrations of 1–5 wt% based upon their chemistry; however it leached out in BSA at higher concentrations. Though, low concentrations of IPM reduced both liquid water and water vapour permeability; at higher IPM content liquid permeability did not improved significantly. In general, the polyurethane materials showed much lower water permeability compared with currently used silicone packaging material for electronic implants. In addition, cytotoxicity assessment of IPM containing polyurethanes showed no evidence of cytotoxcity up to 5 wt% IPM.

  16. Development and characterization of a new membrane system for the environmental control of biopiles used for the treatment of contaminated soils

    International Nuclear Information System (INIS)

    Schoefs, O.; Deschenes, L.; Samson, R.

    1997-01-01

    Four biopiles containing soils contaminated with diesel oil were used in a study to evaluate whether or not to use solar energy to heat up the soil. Temperature is an important factor that controls biodegradation in biopile degradation. Extreme hot and cold temperatures make biopile treatments ineffective. A new membrane system for the environmental control of biopiles has been developed which is capable of maintaining the temperature inside the biopiles at a level where biodegradation can occur even in cold temperatures. The commonly used semi-permeable black membrane was compared to a double polyethylene membrane sealed system which had an insulating layer that at times acted as a heating layer. Probes were placed in the biopiles to monitor the temperature and water content. The study showed that solar radiation had a big impact on the soil temperature and the use of a double polyethylene membrane system increased the temperature of the biopiles to allow for an extended biopile treatment during winter and also in cold regions. A mathematical model to simulate the temperature profile inside the biopile was also developed

  17. Encapsulation and immobilization of papain in electrospun nanofibrous membranes of PVA cross-linked with glutaraldehyde vapor

    Energy Technology Data Exchange (ETDEWEB)

    Moreno-Cortez, Iván E. [Centro de Investigación en Química Aplicada (CIQA), Blvd. Enrique Reyna # 140, San José de los Cerritos, Saltillo, Coahuila 25100, México (Mexico); Universidad Autónoma de Nuevo León (UANL), Fac. de Ingeniería Mecánica y Eléctrica (FIME), Av. Universidad S/N, Cd. Universitaria, San Nicolás de los Garza, Nuevo León C.P. 66450, México (Mexico); Universidad Autónoma de Nuevo León (UANL), Centro de Innovación, Investigación y Desarrollo en Ingeniería y Tecnología (CIIDIT), Apodaca, Nuevo León, México (Mexico); Romero-García, Jorge, E-mail: jromero@ciqa.mx [Centro de Investigación en Química Aplicada (CIQA), Blvd. Enrique Reyna # 140, San José de los Cerritos, Saltillo, Coahuila 25100, México (Mexico); and others

    2015-07-01

    In this paper, papain enzyme (E.C. 3.4.22.2, 1.6 U/mg) was successfully immobilized in poly(vinyl alcohol) (PVA) nanofibers prepared by electrospinning. The morphology of the electrospun nanofibers was characterized by scanning electron microscopy (SEM) and the diameter distribution was in the range of 80 to 170 nm. The presence of the enzyme within the PVA nanofibers was confirmed by infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and energy dispersive X-ray spectroscopy (EDXS) analyses. The maximum catalytic activity was reached when the enzyme loading was 13%. The immobilization of papain in the nanofiber membrane was achieved by chemical crosslinking with a glutaraldehyde vapor treatment (GAvt). The catalytic activity of the immobilized papain was 88% with respect to the free enzyme. The crosslinking time by GAvt to immobilize the enzyme onto the nanofiber mat was 24 h, and the enzyme retained its catalytic activity after six cycles. The crosslinked samples maintained 40% of their initial activity after being stored for 14 days. PVA electrospun nanofibers are excellent matrices for the immobilization of enzymes due to their high surface area and their nanoporous structure. - Highlights: • Successfully attempt to immobilize the papain enzyme in electrospun nanofibers • The morphology of nanofibers did not change at moderate enzyme concentrations. • The retained activity of the immobilized enzyme was 88% relative to the free enzyme. • The immobilized enzyme retains 40% of the initial activity after 14 days of storage. • Potential application of this work in the fabrication of biosensors specialized in the detection of metal ions.

  18. Encapsulation and immobilization of papain in electrospun nanofibrous membranes of PVA cross-linked with glutaraldehyde vapor

    International Nuclear Information System (INIS)

    Moreno-Cortez, Iván E.; Romero-García, Jorge

    2015-01-01

    In this paper, papain enzyme (E.C. 3.4.22.2, 1.6 U/mg) was successfully immobilized in poly(vinyl alcohol) (PVA) nanofibers prepared by electrospinning. The morphology of the electrospun nanofibers was characterized by scanning electron microscopy (SEM) and the diameter distribution was in the range of 80 to 170 nm. The presence of the enzyme within the PVA nanofibers was confirmed by infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and energy dispersive X-ray spectroscopy (EDXS) analyses. The maximum catalytic activity was reached when the enzyme loading was 13%. The immobilization of papain in the nanofiber membrane was achieved by chemical crosslinking with a glutaraldehyde vapor treatment (GAvt). The catalytic activity of the immobilized papain was 88% with respect to the free enzyme. The crosslinking time by GAvt to immobilize the enzyme onto the nanofiber mat was 24 h, and the enzyme retained its catalytic activity after six cycles. The crosslinked samples maintained 40% of their initial activity after being stored for 14 days. PVA electrospun nanofibers are excellent matrices for the immobilization of enzymes due to their high surface area and their nanoporous structure. - Highlights: • Successfully attempt to immobilize the papain enzyme in electrospun nanofibers • The morphology of nanofibers did not change at moderate enzyme concentrations. • The retained activity of the immobilized enzyme was 88% relative to the free enzyme. • The immobilized enzyme retains 40% of the initial activity after 14 days of storage. • Potential application of this work in the fabrication of biosensors specialized in the detection of metal ions

  19. Influence of foundation layering on soil-structure system motion

    International Nuclear Information System (INIS)

    Philippacopoulos, A.J.

    1985-01-01

    This paper is concerned with effects on structural motion due to layering of the foundation. Impedance functions for foundations which consist of a layer resting on a viscoelastic half-space are used on a simple 3-dof SSI system and transfer functions are generated. It is shown that the layering of the foundation effects the motion of the SSI system. These effects are more pronounced for shallow layers with large difference in shear wave velocity from the underlying half-space. (orig.)

  20. Final report: Seven-layer membrane electrode assembly - an innovative approach to PEM fuel cell design

    Energy Technology Data Exchange (ETDEWEB)

    Chapman, A.

    2005-07-01

    Costs of materials and fabrication, rather than appropriateness of technology, are the major barriers to the sales of fuel cells. With the objective of reducing costs, potential alternative component materials for (a) the fluid flow plate (FFP) and (b) the gas diffusion layers were investigated. The concept of a 7-layer membrane electrode assembly (MEA), in which components are bonded into a unitised module, was also studied. The advantages of the bonded cell, and the flow field design, are expounded. Low-cost carbon particle composites were developed for the FFPs. The modular 7-layer MEA has an order of magnitude saving over current materials. Overall, the study has led to a greater volumetric power output, lower costs and greater reliability. The work was carried out by Morgan Group Technology Limited and funded by the DTI.

  1. Improved Seasonal Prediction of European Summer Temperatures With New Five-Layer Soil-Hydrology Scheme

    Science.gov (United States)

    Bunzel, Felix; Müller, Wolfgang A.; Dobrynin, Mikhail; Fröhlich, Kristina; Hagemann, Stefan; Pohlmann, Holger; Stacke, Tobias; Baehr, Johanna

    2018-01-01

    We evaluate the impact of a new five-layer soil-hydrology scheme on seasonal hindcast skill of 2 m temperatures over Europe obtained with the Max Planck Institute Earth System Model (MPI-ESM). Assimilation experiments from 1981 to 2010 and 10-member seasonal hindcasts initialized on 1 May each year are performed with MPI-ESM in two soil configurations, one using a bucket scheme and one a new five-layer soil-hydrology scheme. We find the seasonal hindcast skill for European summer temperatures to improve with the five-layer scheme compared to the bucket scheme and investigate possible causes for these improvements. First, improved indirect soil moisture assimilation allows for enhanced soil moisture-temperature feedbacks in the hindcasts. Additionally, this leads to improved prediction of anomalies in the 500 hPa geopotential height surface, reflecting more realistic atmospheric circulation patterns over Europe.

  2. Evaluation of microbial diversity of different soil layers at a contaminated diesel site

    CSIR Research Space (South Africa)

    Maila, MP

    2005-01-01

    Full Text Available with high TPH removal. Analysis of the microbial diversity in the different soil layers using functional diversity (community-level physiological profile, via Biolog) and genetic diversity using polymerase chain reaction-denaturing gradient gel...

  3. Bulk and contact resistances of gas diffusion layers in proton exchange membrane fuel cells

    Science.gov (United States)

    Ye, Donghao; Gauthier, Eric; Benziger, Jay B.; Pan, Mu

    2014-06-01

    A multi-electrode probe is employed to distinguish the bulk and contact resistances of the catalyst layer (CL) and the gas diffusion layer (GDL) with the bipolar plate (BPP). Resistances are compared for Vulcan carbon catalyst layers (CL), carbon paper and carbon cloth GDL materials, and GDLs with microporous layers (MPL). The Vulcan carbon catalyst layer bulk resistance is 100 times greater than the bulk resistance of carbon paper GDL (Toray TG-H-120). Carbon cloth (CCWP) has bulk and contact resistances twice those of carbon paper. Compression of the GDL decreases the GDL contact resistance, but has little effect on the bulk resistance. Treatment of the GDL with polytetrafluoroethylene (PTFE) increases the contact resistance, but has little effect on the bulk resistance. A microporous layer (MPL) added to the GDL decreases the contact resistance, but has little effect on the bulk resistance. An equivalent circuit model shows that for channels less than 1 mm wide the contact resistance is the major source of electronic resistance and is about 10% of the total ohmic resistance associated with the membrane electrode assembly.

  4. Development of gas diffusion layer using water based carbon slurry for proton exchange membrane fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Lin, J.F.; Liu, X.; Adame, A.; Villacorta, R. [Fuel Cell Research Laboratory, Engineering Technology Department, Arizona State University, Mesa, AZ 85212 (United States); Wertz, J. [Hollingsworth and Vose Co., A.K. Nicholson Research Lab, 219 Townsend Road, West Groton, MA 01472 (United States); Ahmad, R.; Thommes, M. [Quantachrome Instruments, 1900 Corporate Drive, Boynton Beach, FL 33426 (United States); Kannan, A.M., E-mail: amk@asu.ed [Fuel Cell Research Laboratory, Engineering Technology Department, Arizona State University, Mesa, AZ 85212 (United States)

    2011-01-01

    The micro-porous layer of gas diffusion layers (GDLs) was fabricated with the carbon slurry dispersed in water containing sodium dodecyl sulfate (SDS), by wire rod coating process. The aqueous carbon slurry with micelle-encapsulation was highly consistent and stable without losing any homogeneity even after adding polytetrafluoroethylene (PTFE) binder for hundreds of hours. The surface morphology, contact angle and pore size distribution of the GDLs were examined using SEM, Goniometer and Hg Porosimeter, respectively. GDLs fabricated with various SDS concentrations were assembled into MEAs and evaluated in a single cell PEMFC under diverse operating relative humidity (RH) conditions using H{sub 2}/O{sub 2} and H{sub 2}/air as reactants. The peak power density of the single cell using the GDLs with optimum SDS concentration was 1400 and 500 mW cm{sup -2} with H{sub 2}/O{sub 2} and H{sub 2}/air at 90% RH, respectively. GDLs were also fabricated with isopropyl alcohol (IPA) based carbon slurry for fuel cell performance comparison. It was found that the composition of the carbon slurry, specifically SDS concentration played a critical role in controlling the pore diameter as well as the corresponding pore volumes of the GDLs.

  5. POLYETHYLENE ENCAPSULATION

    International Nuclear Information System (INIS)

    Kalb, P.

    2001-01-01

    Polyethylene microencapsulation physically homogenizes and incorporates mixed waste particles within a molten polymer matrix, forming a solidified final waste form upon cooling. Each individual particle of waste is embedded within the polymer block and is surrounded by a durable, leach-resistant coating. The process has been successfully applied for the treatment of a broad range of mixed wastes, including evaporator concentrate salts, soil, sludges, incinerator ash, off-gas blowdown solutions, decontamination solutions, molten salt oxidation process residuals, ion exchange resins, granular activated carbon, shredded dry active waste, spill clean-up residuals, depleted uranium powders, and failed grout waste forms. For waste streams containing high concentrations of soluble toxic metal contaminants, additives can be used to further reduce leachability, thus improving waste loadings while meeting or exceeding regulatory disposal criteria. In this configuration, contaminants are both chemically stabilized and physically solidified, making the process a true stabilization/solidification (S/S) technology. Unlike conventional hydraulic cement grouts or thermosetting polymers, thermoplastic polymers such as polyethylene require no chemical. reaction for solidification. Thus, a stable, solid, final waste form product is assured on cooling. Variations in waste chemistry over time do not affect processing parameters and do not require reformulation of the recipe. Incorporation of waste particles within the polymer matrix serves as an aggregate and improves the mechanical strength and integrity of the waste form. The compressive strength of polyethylene microencapsulated waste forms varies based on the type and quantity of waste encapsulated, but is typically between 7 and 17.2 MPa (1000 and 2500 psi), well above the minimum strength of 0.4 MPa (160 psi) recommended by the U.S. Nuclear Regulatory Commission (NRC) for low-level radioactive waste forms in support of 10 CFR 61

  6. Modelling and sequential simulation of multi-tubular metallic membrane and techno-economics of a hydrogen production process employing thin-layer membrane reactor

    KAUST Repository

    Shafiee, Alireza

    2016-09-24

    A theoretical model for multi-tubular palladium-based membrane is proposed in this paper and validated against experimental data for two different sized membrane modules that operate at high temperatures. The model is used in a sequential simulation format to describe and analyse pure hydrogen and hydrogen binary mixture separations, and then extended to simulate an industrial scale membrane unit. This model is used as a sub-routine within an ASPEN Plus model to simulate a membrane reactor in a steam reforming hydrogen production plant. A techno-economic analysis is then conducted using the validated model for a plant producing 300 TPD of hydrogen. The plant utilises a thin (2.5 μm) defect-free and selective layer (Pd75Ag25 alloy) membrane reactor. The economic sensitivity analysis results show usefulness in finding the optimum operating condition that achieves minimum hydrogen production cost at break-even point. A hydrogen production cost of 1.98 $/kg is estimated while the cost of the thin-layer selective membrane is found to constitute 29% of total process capital cost. These results indicate the competiveness of this thin-layer membrane process against conventional methods of hydrogen production. © 2016 Hydrogen Energy Publications LLC

  7. Modeling of 1-D nitrate transport in single layer soils | Dike | Journal ...

    African Journals Online (AJOL)

    The transport of nitrate in laboratory single soil columns of sand, laterite and clay were investigated after 21 days. The 1-D contaminant transport model by Notodarmojo et al (1991) for single layer soils were calibrated and verified using field data collected from a refuse dump site at avu, owerri, Imo state. The experimental ...

  8. Predicting Subsurface Soil Layering and Landslide Risk with Artificial Neural Networks

    DEFF Research Database (Denmark)

    Farrokhzad, Farzad; Barari, Amin; Ibsen, Lars Bo

    2011-01-01

    This paper is concerned principally with the application of ANN model in geotechnical engineering. In particular the application for subsurface soil layering and landslide analysis is discussed in more detail. Three ANN models are trained using the required geotechnical data obtained from...... networks are capable of predicting variations in the soil profile and assessing the landslide hazard with an acceptable level of confidence....

  9. Acoustically excited encapsulated microbubbles and mitigation of biofouling

    KAUST Repository

    Qamar, Adnan

    2017-08-31

    Provided herein is a universally applicable biofouling mitigation technology using acoustically excited encapsulated microbubbles that disrupt biofilm or biofilm formation. For example, a method of reducing biofilm formation or removing biofilm in a membrane filtration system is provided in which a feed solution comprising encapsulated microbubbles is provided to the membrane under conditions that allow the encapsulated microbubbles to embed in a biofilm. Sonication of the embedded, encapsulated microbubbles disrupts the biofilm. Thus, provided herein is a membrane filtration system for performing the methods and encapsulated microbubbles specifically selected for binding to extracellular polymeric substances (EFS) in a biofilm.

  10. New insights into comparison between synthetic and practical municipal wastewater in cake layer characteristic analysis of membrane bioreactor.

    Science.gov (United States)

    Zhou, Lijie; Zhuang, Wei-Qin; Wang, Xin; Yu, Ke; Yang, Shufang; Xia, Siqing

    2017-11-01

    In previous studies, cake layer analysis in membrane bioreactor (MBR) was both carried out with synthetic and practical municipal wastewater (SMW and PMW), leading to different results. This study aimed to identify the comparison between SMW and PMW in cake layer characteristic analysis of MBR. Two laboratory-scale anoxic/oxic MBRs were operated for over 90days with SMW and PMW, respectively. Results showed that PMW led to rough cake layer surface with particles, and the aggravation of cake layer formation with thinner and denser cake layer. Additionally, inorganic components, especially Si and Al, in PMW accumulated into cake layer and strengthened the cake layer structure, inducing severer biofouling. However, SMW promoted bacterial metabolism during cake layer formation, thus aggravated the accumulation of organic components into cake layer. Therefore, SMW highlighted the organic components in cake layer, but weakened the inorganic functions in practical MBR operation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. In vivo pharmacological evaluation and efficacy study of methotrexate-encapsulated polymer-coated layered double hydroxide nanoparticles for possible application in the treatment of osteosarcoma.

    Science.gov (United States)

    Ray, Sayantan; Saha, Suman; Sa, Biswanath; Chakraborty, Jui

    2017-04-01

    Considering the existing drawbacks of methotrexate (MTX) with respect to its solubility and toxicity, we incorporated it in a nanoceramic matrix, Mg-Al-layered double hydroxide (LDH) to form LDH-MTX nanoparticles, and the same was in turn encapsulated in a nontoxic and biodegradable polymer, poly (D,L-lactide-co-glycolide) (PLGA), to arrest the initial burst release and dose-dumping-related toxicity, already reported by our group. Our present study was designed to evaluate the pharmacokinetics, tissue distribution, survival rate of the test animals, and antitumor efficacy of the PLGA-LDH-MTX nanoparticles and its counterpart without LDH, PLGA-MTX nanoparticles compared with bare MTX. The median lethal dose (LD 50 ) of the former was higher, compared with bare MTX, using Balb/c nude mice, indicating it to be completely safe for use. Also, a comparative pharmacokinetic and antitumour efficacy study using MTX, PLGA-MTX, and PLGA-LDH-MTX nanoparticles in osteosarcoma-induced Balb/c nude mice in vivo demonstrated superiority of PLGA-LDH-MTX as compared to PLGA-MTX and bare MTX. The results suggest that PLGA-LDH-MTX nanoparticles might exhibit potential advantages over the present-day chemotherapy over bare MTX, for the possibility of treatment of osteosarcoma.

  12. Soil water characteristics of Middle Pleistocene paleosol layers on ...

    African Journals Online (AJOL)

    Administrator

    2011-09-14

    Sep 14, 2011 ... models to be fitted to the SWCC data, the van Genuchten model was applicable .... There is some risk that ... optimal model for the eight paleosol samples. ..... Code for Quantifying the Hydraulic Functions of Unsaturated Soils.

  13. Applied satellite remote sensing to runoff analysis: Through the effective depth of soil layer

    International Nuclear Information System (INIS)

    Yamamoto, Y.; Kondoh, T.; Kida, T.; Nishikawa, H.

    2002-01-01

    The thickness of the soil layers in which tree roots are able to develop freely influences forest composition and growth. Trees growing in shallow soil are usually less well supplied with water and mineral nutrients than those growing in deeper soil. A soil may be deep in an absolute sense but, because of a relatively impervious layer, such as hardpan or because of a high water-table, may be shallow in a physiological sense. Penetrability measurements have been found useful in evaluating the influence of different forest types on the physical properties of soils. Commonly the penetrability of soils can be measured by using the Hasegawa-formed soil penetrometer and can be judged as the soil softness content (SSC). Previous studies report soil with more than 1.9 cm/drop of SSC to be highly permeable and therefore roots are more likely to be extensively developed. Based upon this theory the depth of soil layer with more than 1.9 cm/drop of SSC can be defined as the Effective Depth of Soil Layer (EDSL). We examined the relationship between the Ratio Vegetation Index (RVI) and the EDSL and established a 'Runoff Simulation Model (RSM)' based upon the theory of the Storage Function Model method. The conclusions are that (1) a strong positive correlation between the RVI (ground measured) and the EDSL was given, (2) applying results of conclusion (1) to satellite analysis a similar correlation between the RVI (satellite analysis of JERS 1/OPS data) and the EDSL was observed and (3) the simulated storm-runoff hydro graph coincides with the observed one well

  14. Removal of nitrogen by a layered soil infiltration system during intermittent storm events.

    Science.gov (United States)

    Cho, Kang Woo; Song, Kyung Guen; Cho, Jin Woo; Kim, Tae Gyun; Ahn, Kyu Hong

    2009-07-01

    The fates of various nitrogen species were investigated in a layered biological infiltration system under an intermittently wetting regime. The layered system consisted of a mulch layer, coarse soil layer (CSL), and fine soil layer (FSL). The effects of soil texture were assessed focusing on the infiltration rate and the removal of inorganic nitrogen species. The infiltration rate drastically decreased when the uniformity coefficient was larger than four. The ammonium in the synthetic runoff was shown to be removed via adsorption during the stormwater dosing and nitrification during subsequent dry days. Stable ammonium adsorption was observed when the silt and clay content of CSL was greater than 3%. This study revealed that the nitrate leaching was caused by nitrification during dry days. Various patterns of nitrate flushing were observed depending on the soil configuration. The washout of nitrate was more severe as the silt/clay content of the CSL was greater. However, proper layering of soil proved to enhance the nitrate removal. Consequently, a strictly sandy CSL over FSL with a silt and clay content of 10% was the best configuration for the removal of ammonium and nitrate.

  15. Experimental study of soil-structure interaction for proving the three dimensional thin layered element method

    International Nuclear Information System (INIS)

    Kuwabara, Y.; Ogiwara, Y.; Suzuki, T.; Tsuchiya, H.; Nakayama, M.

    1981-01-01

    It is generally recognized that the earthquake response of a structure can be significantly affected by the dynamic interaction between the structure and the surrounding soil. Dynamic soil-structure interaction effects are usually analyzed by using a lumped mass model or a finite element model. In the lumped mass model, the soil is represented by springs and dashpots based on the half-space elastic theory. Each model has its advantages and limitations. The Three Dimensional Thin Layered Element Theory has been developed by Dr. Hiroshi Tajimi based on the combined results of the abovementioned lumped mass model and finite element model. The main characteristic of this theory is that, in consideration and can be applied in the analysis of many problems in soil-structure interaction, such as those involving radiation damping, embedded structures, and multi-layered soil deposits. This paper describes test results on a small scale model used to prove the validity of the computer program based on the Thin Layered Element Theory. As a numerical example, the response analysis of a PWR nuclear power plant is carried out using this program. The vibration test model is simplified and the scale is 1/750 for line. The soil layer of the model is made of congealed gelatine. The test soil layer is 80 cm long, 35 cm wide and 10 cm thick. The super structure is a one mass model made of metal sheet spring and solid mass metal. As fixed inputs, sinusoidal waves (10, 20 gal level) are used. The displacements of the top and base of the super structure, and the accelerations and the displacements of the shaking table are measured. The main parameter of the test is the shear wave velocity of the soil layer. (orig./RW)

  16. Responses of plant available water and forest productivity to variably layered coarse textured soils

    Science.gov (United States)

    Huang, Mingbin; Barbour, Lee; Elshorbagy, Amin; Si, Bing; Zettl, Julie

    2010-05-01

    Reforestation is a primary end use for reconstructed soils following oil sands mining in northern Alberta, Canada. Limited soil water conditions strongly restrict plant growth. Previous research has shown that layering of sandy soils can produce enhanced water availability for plant growth; however, the effect of gradation on these enhancements is not well defined. The objective of this study was to evaluate the effect of soil texture (gradation and layering) on plant available water and consequently on forest productivity for reclaimed coarse textured soils. A previously validated system dynamics (SD) model of soil moisture dynamics was coupled with ecophysiological and biogeochemical processes model, Biome-BGC-SD, to simulate forest dynamics for different soil profiles. These profiles included contrasting 50 cm textural layers of finer sand overlying coarser sand in which the sand layers had either a well graded or uniform soil texture. These profiles were compared to uniform profiles of the same sands. Three tree species of jack pine (Pinus banksiana Lamb.), white spruce (Picea glauce Voss.), and trembling aspen (Populus tremuloides Michx.) were simulated using a 50 year climatic data base from northern Alberta. Available water holding capacity (AWHC) was used to identify soil moisture regime, and leaf area index (LAI) and net primary production (NPP) were used as indices of forest productivity. Published physiological parameters were used in the Biome-BGC-SD model. Relative productivity was assessed by comparing model predictions to the measured above-ground biomass dynamics for the three tree species, and was then used to study the responses of forest leaf area index and potential productivity to AWHC on different soil profiles. Simulated results indicated soil layering could significantly increase AWHC in the 1-m profile for coarse textured soils. This enhanced AWHC could result in an increase in forest LAI and NPP. The increased extent varied with soil

  17. Synthesis and characterization of a stable humic-urease complex: application to barley seed encapsulation for improving N uptake.

    Science.gov (United States)

    Mvila, Beaufray G; Pilar-Izquierdo, María C; Busto, María D; Perez-Mateos, Manuel; Ortega, Natividad

    2016-07-01

    Most N fertilizers added to soil are not efficiently used by plants and are lost to the atmosphere or leached from the soil, causing environmental pollution and increasing cost. Barley seed encapsulation in calcium alginate gels containing free or immobilized urease to enhance plant utilization of soil N was investigated. Urease was immobilized with soil humic acids (HA). A central composite face-centered design was applied to optimize the immobilization process, reaching an immobilization yield of 127%. Soil stability of urease was enhanced after the immobilization. Seed encapsulation with free urease (FU) and humic-urease complex (HUC) resulted in a urease activity retention in the coating layer of 46% and 24%, and in germination rates of 87% and 92%, respectively. Under pot culture conditions, the pots planted with seeds encapsulated with FU and HUC showed higher ammonium N (NH4 (+) -N) (26% and 64%, respectively) than the control soil at 28 days after planting (DAP). Moreover, the seed encapsulation with FU and HUC increased the N uptake 83% and 97%, respectively, at 35 DAP. Seed encapsulation with urease could substantially contribute to enhancing plant N nutrition in the early stages of seedling establishment. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

  18. Chemical composition of the humus layer, mineral soil and soil solution of 150 forest stands in the Netherlands in 1990

    NARCIS (Netherlands)

    Vries, de W.; Leeters, E.E.J.M.

    2001-01-01

    A nationwide assessment of the chemical composition of the humus layer, mineral topsoil (0-30 cm) and soil solution in both topsoil and subsoil (60-100 cm) was made for 150 forest stands in the year 1990. The stands, which were part of the national forest inventory on vitality, included seven tree

  19. Slow-release NPK fertilizer encapsulated by carboxymethyl cellulose-based nanocomposite with the function of water retention in soil.

    Science.gov (United States)

    Olad, Ali; Zebhi, Hamid; Salari, Dariush; Mirmohseni, Abdolreza; Reyhani Tabar, Adel

    2018-09-01

    In this study, new slow release fertilizer encapsulated by superabsorbent nanocomposite was prepared by in-situ graft polymerization of sulfonated-carboxymethyl cellulose (SCMC) with acrylic acid (AA) in the presence of polyvinylpyrrolidone (PVP), silica nanoparticles and nitrogen (N), phosphorous (P), and potassium (K) (NPK) fertilizer compound. The prepared materials were characterized by FT-IR, XRD and scanning electron microscopy (SEM) techniques. The incorporation of NPK fertilizer into hydrogel nanocomposite network was verified by results of these analyses. Also, the swelling behavior in various pH and saline solutions as well as water retention capability of the prepared hydrogel nanocomposite was evaluated. The fertilizer release behavior of the NPK loaded hydrogel nanocomposite was in good agreement with the standard of Committee of European Normalization (CEN), indicating its excellent slow release property. These good characteristics revealed that the hydrogel nanocomposite fertilizer formulation can be practically used in agricultural and horticultural applications. Copyright © 2018 Elsevier B.V. All rights reserved.

  20. [Soil organic carbon mineralization of Black Locust forest in the deep soil layer of the hilly region of the Loess Plateau, China].

    Science.gov (United States)

    Ma, Xin-Xin; Xu, Ming-Xiang; Yang, Kai

    2012-11-01

    The deep soil layer (below 100 cm) stores considerable soil organic carbon (SOC). We can reveal its stability and provide the basis for certification of the deep soil carbon sinks by studying the SOC mineralization in the deep soil layer. With the shallow soil layer (0-100 cm) as control, the SOC mineralization under the condition (temperature 15 degrees C, the soil water content 8%) of Black Locust forest in the deep soil layer (100-400 cm) of the hilly region of the Loess Plateau was studied. The results showed that: (1) There was a downward trend in the total SOC mineralization with the increase of soil depth. The total SOC mineralization in the sub-deep soil (100-200 cm) and deep soil (200-400 cm) were equivalent to approximately 88.1% and 67.8% of that in the shallow layer (0-100 cm). (2) Throughout the carbon mineralization process, the same as the shallow soil, the sub-deep and deep soil can be divided into 3 stages. In the rapid decomposition phase, the ratio of the mineralization or organic carbon to the total mineralization in the sub-deep and deep layer (0-10 d) was approximately 50% of that in the shallow layer (0-17 d). In the slow decomposition phase, the ratio of organic carbon mineralization to total mineralization in the sub-deep, deep layer (11-45 d) was 150% of that in the shallow layer (18-45 d). There was no significant difference in this ratio among these three layers (46-62 d) in the relatively stable stage. (3) There was no significant difference (P > 0.05) in the mineralization rate of SOC among the shallow, sub-deep, deep layers. The stability of SOC in the deep soil layer (100-400 cm) was similar to that in the shallow soil layer and the SOC in the deep soil layer was also involved in the global carbon cycle. The change of SOC in the deep soil layer should be taken into account when estimating the effects of soil carbon sequestration in the Hilly Region of the Loess Plateau, China.

  1. Effect of atomic layer deposition coatings on the surface structure of anodic aluminum oxide membranes.

    Science.gov (United States)

    Xiong, Guang; Elam, Jeffrey W; Feng, Hao; Han, Catherine Y; Wang, Hsien-Hau; Iton, Lennox E; Curtiss, Larry A; Pellin, Michael J; Kung, Mayfair; Kung, Harold; Stair, Peter C

    2005-07-28

    Anodic aluminum oxide (AAO) membranes were characterized by UV Raman and FT-IR spectroscopies before and after coating the entire surface (including the interior pore walls) of the AAO membranes by atomic layer deposition (ALD). UV Raman reveals the presence of aluminum oxalate in bulk AAO, both before and after ALD coating with Al2O3, because of acid anion incorporation during the anodization process used to produce AAO membranes. The aluminum oxalate in AAO exhibits remarkable thermal stability, not totally decomposing in air until exposed to a temperature >900 degrees C. ALD was used to cover the surface of AAO with either Al2O3 or TiO2. Uncoated AAO have FT-IR spectra with two separate types of OH stretches that can be assigned to isolated OH groups and hydrogen-bonded surface OH groups, respectively. In contrast, AAO surfaces coated by ALD with Al2O3 display a single, broad band of hydrogen-bonded OH groups. AAO substrates coated with TiO2 show a more complicated behavior. UV Raman results show that very thin TiO2 coatings (1 nm) are not stable upon annealing to 500 degrees C. In contrast, thicker coatings can totally cover the contaminated alumina surface and are stable at temperatures in excess of 500 degrees C.

  2. Pore Pressure Response to Groundwater Fluctuations in Saturated Double-Layered Soil

    Directory of Open Access Journals (Sweden)

    Hongwei Ying

    2015-01-01

    Full Text Available Analytical solutions are developed for one-dimensional consolidation of double-layered saturated soil subjected to groundwater fluctuations. The solutions are derived by an explicit mathematical procedure using Duhamel’s theorem in conjunction with a Fourier series, when groundwater fluctuation is described by a general time-dependent function and assumed to be the pore water pressure variations at the upper boundary. Taking as an example the harmonic groundwater fluctuation, the relevant response of the excess pore water pressure is discussed in detail, and the main influencing factors of the excess pore pressure distribution are analyzed. A dimensionless parameter θ has been introduced because it significantly affects the phase and the amplitude of excess pore pressures. The influences of the coefficients of permeability and compressibility of soil on the excess pore pressure distribution are different and cannot be incorporated into the coefficient of consolidation in double-layered soil. The relative permeability ratio of two clayey soils also plays an important role on the curves of the distributions of the excess pore pressures. The effects of the thickness of the soil layer on the excess pore pressure distribution should be considered together with the dimensionless parameter θ and the permeability and compressibility of the double-layered soil system.

  3. Technology of mammalian cell encapsulation

    NARCIS (Netherlands)

    Uludag, H; De Vos, P; Tresco, PA

    2000-01-01

    Entrapment of mammalian cells in physical membranes has been practiced since the early 1950s when it was originally introduced as a basic research tool. The method has since been developed based on the promise of its therapeutic usefulness in tissue transplantation. Encapsulation physically isolates

  4. Modelling of the interface between the geosphere and the biosphere: discharge through a soil layer

    International Nuclear Information System (INIS)

    Elert, M.; Argaerde, A.C.; Ericsson, A.M.

    1988-12-01

    Radionuclides released from an underground repository can be transported by deep groundwater to the biosphere. The deep groundwater can be discharged to an agricultural area or a bog. In this report an evaluation is made of the resulting distribution of radionuclides in the upper soil and the release of radionuclides to a creek. From these environments, radionuclides can follow different exposure pathways to man. In order to evaluate the radionuclide movement to and retention in the soil surface, the hydrology in the superficial layers has been studied with the help of computer models. The chemical environment in soil was studied with special emphasis on radionuclide mobility. Examples of parameters which affect this mobility and which were studied are mineral composition, content of organic material, pH and redox potential. The chemical behaviour of the radionuclides iodine, cesium, radium, uranium, neptunium and americium was the topic of a literature survey. For the work in this report, radionuclide mobility in soils is represented by the equilibrium distribution coefficient, K d . The radionuclide transport calculations showed that only those radionuclides which are sorbed strongly in the soil (i.e. radium, cesium and americium) have retention times longer than the expected lifetime of the soil layer itself. This would also be the case for neptunium and uranium if reducing conditions are found at the base of the soil column. For only slightly sorbing nuclides no important retention was found. The retarding effects of the soil layer is less than that of a sediment layer in a lake (the subject of a previous study). because of the greater water turnover in the soil. Several limitations to current knowledge and modelling techniques have been identified, and suggestion for possible improvement have been made. (85 refs.) (au)

  5. Inversion of soil electrical conductivity data to estimate layered soil properties

    Science.gov (United States)

    CBulk apparent soil electrical conductivity (ECa) sensors respond to multiple soil properties, including clay content, water content, and salt content (i.e., salinity). They provide a single sensor value for an entire soil profile down to a sensor-dependent measurement depth, weighted by a nonlinear...

  6. Asymmetric bi-layer PFSA membranes as model systems for the study of water management in the PEMFC.

    Science.gov (United States)

    Peng, Z; Peng, A Z; Morin, A; Huguet, P; Lanteri, Y; Deabate, S

    2014-10-14

    New bi-layer PFSA membranes made of Nafion® NRE212 and Aquivion™ E79-05s with different equivalent weights are prepared with the aim of managing water repartition in the PEMFC. The membrane water transport properties, i.e. back-diffusion and electroosmosis, as well as the electrochemical performances, are compared to those of state-of-art materials. The actual water content (the inner water concentration profile across the membrane thickness) is measured under operation in the fuel cell by in situ Raman microspectroscopy. The orientation of the equivalent weight gradient with respect to the water external gradient and to the proton flow direction affects the membrane water content, the water transport ability and, thus, the fuel cell performances. Higher power outputs, related to lower ohmic losses, are observed when the membrane is assembled with the lower equivalent weight layer (Aquivion™) at the anode side. This orientation, corresponding to enhanced water transport by back-flow while electroosmosis remains unaffected, results in the higher hydration of the membrane and of the anode active layer during operation. Also, polarization data suggest a different water repartition in the fuel cell along the on-plane direction. Even if the interest in multi-layer PFSA membranes as perspective electrolytes for PEMFCs is not definitively attested, these materials appear to be excellent model systems to establish relationships between the membrane transport properties, the water distribution in the fuel cell and the electrochemical performances. Thanks to the micrometric resolution, in situ Raman microspectroscopy proves to be a unique tool to measure the actual hydration of the membrane at the surface swept by the hydrated feed gases during operation, so that it can be used as a local probe of the water concentration evolution along the gas distribution channels according to changing working conditions.

  7. Modelling and sequential simulation of multi-tubular metallic membrane and techno-economics of a hydrogen production process employing thin-layer membrane reactor

    KAUST Repository

    Shafiee, Alireza; Arab, Mobin; Lai, Zhiping; Liu, Zongwen; Abbas, Ali

    2016-01-01

    reforming hydrogen production plant. A techno-economic analysis is then conducted using the validated model for a plant producing 300 TPD of hydrogen. The plant utilises a thin (2.5 μm) defect-free and selective layer (Pd75Ag25 alloy) membrane reactor

  8. Erosion of cohesive soil layers above underground conduits

    Directory of Open Access Journals (Sweden)

    Luu Li-Hua

    2017-01-01

    Full Text Available Using a recently developed 2D numerical modelling that combines Discrete Element (DEM and Lattice Boltzmann methods (LBM, we simulate the destabilisation by an hydraulic gradient of a cohesive granular soil clogging the top of an underground conduit. We aim to perform a multi-scale study that relates the grain scale behavior to the macroscopic erosion process. In particular, we study the influence of the flow conditions and the inter-particle contact forces intensity on the erosion kinetic.

  9. Erosion of cohesive soil layers above underground conduits

    Science.gov (United States)

    Luu, Li-Hua; Philippe, Pierre; Noury, Gildas; Perrin, Jérôme; Brivois, Olivier

    2017-06-01

    Using a recently developed 2D numerical modelling that combines Discrete Element (DEM) and Lattice Boltzmann methods (LBM), we simulate the destabilisation by an hydraulic gradient of a cohesive granular soil clogging the top of an underground conduit. We aim to perform a multi-scale study that relates the grain scale behavior to the macroscopic erosion process. In particular, we study the influence of the flow conditions and the inter-particle contact forces intensity on the erosion kinetic.

  10. Recent progress in the applications of layer-by-layer assembly to the preparation of nanostructured ion-rejecting water purification membranes.

    Science.gov (United States)

    Sanyal, Oishi; Lee, Ilsoon

    2014-03-01

    Reverse osmosis (RO) and nanofiltration (NF) are the two dominant membrane separation processes responsible for ion rejection. While RO is highly efficient in removal of ions it needs a high operating pressure and offers very low selectivity between ions. Nanofiltration on the other hand has a comparatively low operating pressure and most commercial membranes offer selectivity in terms of ion rejection. However in many nanofiltration operations rejection of monovalent ions is not appreciable. Therefore a high flux high rejection membrane is needed that can be applied to water purification systems. One such alternative is the usage of polyelectrolyte multilayer membranes that are prepared by the deposition of alternately charged polyelectrolytes via layer-by-layer (LbL) assembly method. LbL is one of the most common self-assembly techniques and finds application in various areas. It has a number of tunable parameters like deposition conditions, number of bilayers deposited etc. which can be manipulated as per the type of application. This technique can be applied to make a nanothin membrane skin which gives high rejection and at the same time allow a high water flux across it. Several research groups have applied this highly versatile technique to prepare membranes that can be employed for water purification. Some of these membranes have shown better performance than the commercial nanofiltration and reverse osmosis membranes. These membranes have the potential to be applied to various different aspects of water treatment like water softening, desalination and recovery of certain ions. Besides the conventional method of LbL technique other alternative methods have also been suggested that can make the technique fast, more efficient and thereby make it more commercially acceptable.

  11. Collecting soil vapor from the Vadose Zone with an instrumented membrane system

    International Nuclear Information System (INIS)

    Martins, S.A.

    1992-07-01

    As part of an on-going program to monitor ground water pollution, the SEAMIST instrumented membrane system was purchased and installed in two boreholes at the Lawrence Livermore National Laboratory (LLNL). SEAMIST is a flexible, removable, polyvinylchloride-coated, nylon membrane tube used to seal the sides of a borehole and to which sampling devices and other types of instrumentation may be attached. This paper describes a method to sample soil vapor (a component of soil gas) with the SEAMIST system from a borehole at several depths simultaneously. The cryotraps used with this technique were tested for their collection efficiency, and those data are presented. Data on the integrity of the SEAMIST borehole seal are also reported

  12. High-permeance crosslinked PTMSP thin-film composite membranes as supports for CO2 selective layer formation

    Directory of Open Access Journals (Sweden)

    Stepan D. Bazhenov

    2016-10-01

    Full Text Available In the development of the composite gas separation membranes for post-combustion CO2 capture, little attention is focused on the optimization of the membrane supports, which satisfy the conditions of this technology. The primary requirements to the membrane supports are concerned with their high CO2 permeance. In this work, the membrane supports with desired characteristics were developed as high-permeance gas separation thin film composite (TFC membranes with the thin defect-free layer from the crosslinked highly permeable polymer, poly[1-(trimethylsilyl-1-propyne] (PTMSP. This layer is insoluble in chloroform and can be used as a gutter layer for the further deposition of the СО2-selective materials from the organic solvents. Crosslinking of PTMSP was performed using polyethyleneimine (PEI and poly (ethyleneglycol diglycidyl ether (PEGDGE as crosslinking agents. Optimal concentrations of PEI in PTMSP and PEGDGE in methanol were selected in order to diminish the undesirable effect on the final membrane gas transport characteristics. The conditions of the kiss-coating technique for the deposition of the thin defect-free PTMSP-based layer, namely, composition of the casting solution and the speed of movement of the porous commercial microfiltration-grade support, were optimized. The procedure of post-treatment with alcohols and alcohol solutions was shown to be crucial for the improvement of gas permeance of the membranes with the crosslinked PTMSP layer having thickness ranging within 1–2.5 μm. The claimed membranes showed the following characteristics: CO2 permeance is equal to 50–54 m3(STP/(m2 h bar (18,500–20,000 GPU, ideal CO2/N2 selectivity is 3.6–3.7, and their selective layers are insoluble in chloroform. Thus, the developed high-permeance TFC membranes are considered as a promising supports for further modification by enhanced CO2 selective layer formation. Keywords: Thin-film composite membrane

  13. Quantification of functional groups and modeling of their ionization behavior in the active layer of FT30 reverse osmosis membrane.

    Science.gov (United States)

    Coronell, Orlando; Mariñas, Benito J; Zhang, Xijing; Cahill, David G

    2008-07-15

    A new experimental approach was developed to measure the concentration of charged functional groups (FGs) in the active layer of thin-film composite reverse osmosis (RO) and nanofiltration (NF) membranes as a function of solution pH. FT30 RO membrane, with a fully aromatic polyamide (PA) active layer sandwiched between a polysulfone support and a coating layer, was used. The experiments consisted of saturating charged FGs with heavy ion probes, and determining the ion probe concentration by Rutherford backscattering spectrometry (RBS). Deprotonated carboxylic groups were saturated with Ag+, and protonated amine groups with W04(2-). The ionization behavior of carboxylic and amine groups was modeled based on acid-base equilibrium theory. While the ionization behavior of amine groups was satisfactorily described by one dissociation constant (pKa = 4.74), two pKa values (5.23 and 8.97) were necessary to describe the titration curve of carboxylic groups. These results were consistent with the bimodal pore size distribution (PSD) of FT30 active layer reported in the literature. The calculated total concentrations of carboxylic and amine groups in the active layer of the FT30 RO membrane studied were 0.432 and 0.036 M, respectively, and the isoelectric point (IEP) was 4.7. The total concentration of carboxylic and amine groups revealed that the degree of cross-linking of the PA active layer of the FT30 RO membrane studied was 94%.

  14. Buried straw layer and plastic mulching increase microlfora diversity in salinized soil

    Institute of Scientific and Technical Information of China (English)

    LI Yu-yi; PANG Huan-cheng; HAN Xiu-fang; YAN Shou-wei; ZHAO Yong-gan; WANG Jing; ZHAI Zhen; ZHANG Jian-li

    2016-01-01

    Salt stress has been increasingly constraining crop productivity in arid lands of the world. In our recent study, salt stress was aleviated and crop productivity was improved remarkably by straw layer burial plus plastic iflm mulching in a saline soil. However, its impact on the microlfora diversity is not wel documented. Field micro-plot experiments were conducted from 2010 to 2011 using four tilage methods: (i) deep tilage with plastic iflm mulching (CK), (i) straw layer burial at 40 cm (S), (ii) straw layer burial plus surface soil mulching with straw material (S+S), and (iv) plastic iflm mulching plus buried straw layer (P+S). Culturable microbes and predominant bacterial communities were studied; based on 16S rDNA, bacterial com-munity structure and abundance were characterized using denaturing gradient gel electrophoresis (DGGE) and polymerase chain reaction (PCR). Results showed that P+S was the most favorable for culturable bacteria, actinomyces and fungi and induced the most diverse genera of bacteria compared to other tilage methods. Soil temperature had signiifcant positive correlations with the number of bacteria, actinomyces and fungi (P<0.01). However, soil water was poorly correlated with any of the microbes. Salt content had a signiifcant negative correlation with the number of microbers, especialy for bacteria and fungi (P<0.01). DGGE analysis showed that the P+S exhibited the highest diversity of bacteria with 20 visible bands folowed by S+S, S and CK. Moreover, P+S had the highest similarity (68%) of bacterial communities with CK. The major bacterial genera in al soil samples wereFirmicutes,Proteobacteria andActinobacteria. Given the considerable increase in microbial growth, the combined use of straw layer burial and plastic iflm mulching could be a practical option for aleviating salt stress effects on soil microbial community and thereby improving crop production in arid saline soils.

  15. The Impact of Wet Soil and Canopy Temperatures on Daytime Boundary-Layer Growth.

    Science.gov (United States)

    Segal, M.; Garratt, J. R.; Kallos, G.; Pielke, R. A.

    1989-12-01

    The impact of very wet soil and canopy temperatures on the surface sensible heat flux, and on related daytime boundary-layer properties is evaluated. For very wet soils, two winter situations are considered, related to significant changes in soil surface temperature: (1) due to weather perturbations at a given location, and (2) due to the climatological north-south temperature gradient. Analyses and scaling of the various boundary-layer properties, and soil surface fluxes affecting the sensible beat flux, have been made; related evaluations show that changes in the sensible heat flux at a given location by a factor of 2 to 3 due to temperature changes related to weather perturbations is not uncommon. These changes result in significant alterations in the boundary-layer depth; in the atmospheric boundary-layer warming; and in the break-up time of the nocturnal surface temperature inversion. Investigation of the impact of the winter latitudinal temperature gradient on the above characteristics indicated that the relative increase in very wet soil sensible heat flux, due to the climatological reduction in the surface temperature in northern latitudes, moderates to some extent its reduction due to the corresponding decrease in solar radiation. Numerical model simulations confirmed these analytical evaluations.In addition, the impact of synoptic temperature perturbations during the transition seasons (fall and spring) on canopy sensible heal fluxes, and the related boundary-layer characteristics mentioned above, was evaluated. Analogous features to those found for very wet soil surfaces occurred also for the canopy situations. Likewise, evaluations were also carried out to explore the impact of high midlatitude foreste areas on the boundary-layer characteristics during the winter as compared to those during the summer. Similar impacts were found in both seasons, regardless of the substantial difference in the daily total solar radiation.

  16. Phosphorus Speciation of Forest-soil Organic Surface Layers using P K-edge XANES Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    J Prietzel; J Thieme; D Paterson

    2011-12-31

    The phosphorus (P) speciation of organic surface layers from two adjacent German forest soils with different degree of water-logging (Stagnosol, Rheic Histosol) was analyzed by P K-edge XANES and subsequent Linear Combination Fitting. In both soils, {approx}70% of the P was inorganic phosphate and {approx}30% organic phosphate; reduced P forms such as phosphonate were absent. The increased degree of water-logging in the Histosol compared to the Stagnosol did not affect P speciation.

  17. Characterization of a bonding-in-liquid technique for liquid encapsulation into MEMS devices

    International Nuclear Information System (INIS)

    Okayama, Yoshiyuki; Nakahara, Keijiro; Arouette, Xavier; Ninomiya, Takeshi; Matsumoto, Yasuaki; Orimo, Yoshinori; Hotta, Atsushi; Omiya, Masaki; Miki, Norihisa

    2010-01-01

    We demonstrate and characterize a new bonding-in-liquid technique (BiLT) for the encapsulation of liquids in MEMS devices. Liquid encapsulation enables innovative MEMS devices with various functions exploiting the unique characteristics of liquids, such as high deformation and spherical shape due to surface tension. Interfusion of air bubbles, variation of the liquid quantity and leakage of the encapsulated liquid must be avoided, or device performance will deteriorate. In BiLT, two structural layers are passively aligned and brought into contact in a solution, and the encapsulation cavities are filled uniformly with liquid, without air bubbles. A UV-curable resin is used as an adhesive that does not require heat or vacuum to bond the layers, but UV irradiation. DI water, glycerin and phosphate buffer saline were successfully encapsulated in silicon structural layers with PDMS membranes. We experimentally evaluated the bond strengths and alignment accuracy of BiLT in order to provide crucial information for the application of this process to the packaging and/or manufacturing of MEMS devices. Since conventional aligners are not applicable to BiLT, we experimentally evaluated the accuracy of an in-solution passive alignment process, which made use of matching concave and convex structures.

  18. Encapsulation process for diffraction gratings.

    Science.gov (United States)

    Ratzsch, Stephan; Kley, Ernst-Bernhard; Tünnermann, Andreas; Szeghalmi, Adriana

    2015-07-13

    Encapsulation of grating structures facilitates an improvement of the optical functionality and/or adds mechanical stability to the fragile structure. Here, we introduce novel encapsulation process of nanoscale patterns based on atomic layer deposition and micro structuring. The overall size of the encapsulated structured surface area is only restricted by the size of the available microstructuring and coating devices; thus, overcoming inherent limitations of existing bonding processes concerning cleanliness, roughness, and curvature of the components. Finally, the process is demonstrated for a transmission grating. The encapsulated grating has 97.5% transmission efficiency in the -1st diffraction order for TM-polarized light, and is being limited by the experimental grating parameters as confirmed by rigorous coupled wave analysis.

  19. Soils and cultural layers of ancient cities in the south of European Russia

    Science.gov (United States)

    Aleksandrovskii, A. L.; Aleksandrovskaya, E. I.; Dolgikh, A. V.; Zamotaev, I. V.; Kurbatova, A. N.

    2015-11-01

    Antique cities in the south of European Russia are characterized by a considerable thickness of their cultural layers (urbosediments) accumulated as construction debris and household wastes. Under the impact of pedogenesis and weathering in dry climate of the steppe zone, these sediments have acquired the features of loesslike low-humus calcareous and alkaline deposits. They are also enriched in many elements (P, Zn, Ca, Cu, Pb, As) related to the diverse anthropogenic activities. The soils developed from such urbosediments can be classified as urbanozems (Urban Technosols), whereas chernozems close to their zonal analogues have developed in the surface layer of sediments covering long-abandoned ancient cities. Similar characteristics have been found for the soils of the medieval and more recent cities in the studied region. Maximum concentrations of the pollutants are locally found in the antique and medieval urbosediments enriched in dyes, handicrafts from nonferrous metals, and other artifacts. Surface soils of ancient cities inherit the properties and composition of the cultural layer. Even in chernozems that developed under steppe vegetation on the surface of the abandoned antique cities of Phanagoria and Tanais for about 1000—1500 years, the concentrations of copper, zinc, and calcium carbonates remain high. Extremely high phosphorus concentrations in these soils should be noted. This is related to the stability of calcium phosphates from animal bones that are abundant in the cultural layer acting as parent material for surface soils.

  20. Modelling desiccation cracking in a homogenous soil clay layer: comparison between different hypotheses on constitutive behaviour

    Directory of Open Access Journals (Sweden)

    Jommi Cristina

    2016-01-01

    Full Text Available Desiccation cracks are usually thought to start from the surface of an evaporating soil layer, and the available simplified models for crack initiation and propagation are based on this hypothesis. On the contrary, experimental results on a Dutch river clay showed that cracks in an evaporating soil layer may start and propagate below the surface, confirming earlier findings by other researchers. A simple one-dimensional model was set up to analyse the consequences of different hypotheses about the material behaviour on the crack onset in a homogenous soil layer undergoing surface drying. The results of the model show that dependence of the material behaviour on the rate of water content change is a necessary requirement for cracks to initiate below the surface. The conclusion suggests that, to properly understand cracking in an evaporating soil layer, an intrinsic time scale for the mechanical response must be accounted for, among all the other factors which were previously highlighted by other researchers. The key factor to predict crack onset below the surface is the dependence of the drying branch of the water retention curve of the compressible soil on the rate of drying, which would be justified by a rate dependent fabric evolution.

  1. Remote Multi-layer Soil Temperature Monitoring System Based on GPRS

    Directory of Open Access Journals (Sweden)

    Ming Kuo CHEN

    2014-02-01

    Full Text Available There is the temperature difference between the upper and lower layer of the shallow soil in the forest. It is a potential energy that can be harvested by thermoelectric generator for the electronic device in the forest. The temperature distribution at different depths of the soil is the first step for thermoelectric generation. A remote multi-layer soil temperature monitoring system based on GPRS is proposed in this paper. The MSP430F149 MCU is used as the main controller of multi-layer soil temperature monitoring system. A temperature acquisition module is designed with DS18B20 and 4 core shielded twisted-pair cable. The GPRS module sends the measured data to remote server through wireless communication network. From the experiments in the campus of Beijing Forestry University, the maximum error of measured temperature in this system is 0.2°C by comparing with professional equipment in the same condition. The results of the experiments show that the system can accurately realize real-time monitoring of multi-layer soil temperature, and the data transmission is stable and reliable.

  2. Encapsulation methods for organic electrical devices

    Science.gov (United States)

    Blum, Yigal D.; Chu, William Siu-Keung; MacQueen, David Brent; Shi, Yijian

    2013-06-18

    The disclosure provides methods and materials suitable for use as encapsulation barriers in electronic devices. In one embodiment, for example, there is provided an electroluminescent device or other electronic device encapsulated by alternating layers of a silicon-containing bonding material and a ceramic material. The encapsulation methods provide, for example, electronic devices with increased stability and shelf-life. The invention is useful, for example, in the field of microelectronic devices.

  3. Development of membrane filters with nanostructured porous layer by coating of metal nanoparticles sintered onto a micro-filter

    International Nuclear Information System (INIS)

    Park, Seok Joo; Park, Young Ok; Lee, Dong Geun; Ryu, Jeong In

    2008-01-01

    The membrane filter adhered with nanostructured porous layer was made by heat treatment after deposition of nanoparticle-agglomerates sintered in aerosol phase onto a conventional micron-fibrous metal filter as a substrate filter. The Sintered-Nanoparticle-Agglomerates-coated NanoStructured porous layer Membrane Filter (SNA-NSMF), whose the filtration performance was improved compared with the conventional metal membrane filters, was developed by adhesion of nanoparticle-agglomerates of dendrite structure sintered onto the micron-fibrous metal filter. The size of nanoparticle-agglomerates of dendrite structure decreased with increasing the sintering temperature because nanoparticle-agglomerates shrank. When shrinking nanoparticle-agglomerates were deposited and treated with heat onto the conventional micron-fibrous metal filter, pore size of nanostructured porous layer decreased. Therefore, pressure drops of SNA-NSMFs increased from 0.3 to 0.516 KPa and filtration efficiencies remarkably increased from 95.612 to 99.9993%

  4. Compost quality and its function as a soil conditioner of recultivation layers - a critical review

    Science.gov (United States)

    Beck-Broichsitter, Steffen; Fleige, Heiner; Horn, Rainer

    2018-01-01

    During a period of 4 years, soil chemical and physical properties of the temporary capping system in Rastorf (Northern Germany) were estimated, whereby compost was partly used as soil improver in the upper recultivation layer. The air capacity and the available water capacity of soil samples were first determined in 2013 (without compost), and then in 2015 (with compost) under laboratory conditions. Herein, the addition of compost had a positive effect on: the air capacity up to 13.4 cm3 cm-3; and the available water capacity up to 20.1 cm3 cm-3 in 2015, in the recultivation layer (0-20 cm). However, taking into account the in situ results of the tensiometer and frequency domain reflectometry measurements, the addition of compost had a negative effect. The soil-compost mixture led to restricted remoistening even after a normal summer drying period in autumn and induced more negative matric potentials in the recultivation layer. In summary, the soil-improving effect of the compost addition, in conjunction with an increased water storage capacity, is undeniable and was demonstrated in a combined field and laboratory study. Therefore, intensive hydrophobicity can inhibit the homogeneous remoistening of the soil, resulting in a decreased hydraulic effectiveness of the sealing system.

  5. Encapsulation Efficiency, Oscillatory Rheometry

    Directory of Open Access Journals (Sweden)

    Z. Mohammad Hassani

    2014-01-01

    Full Text Available Nanoliposomes are one of the most important polar lipid-based nanocarriers which can be used for encapsulation of both hydrophilic and hydrophobic active compounds. In this research, nanoliposomes based on lecithin-polyethylene glycol-gamma oryzanol were prepared by using a modified thermal method. Only one melting peak in DSC curve of gamma oryzanol bearing liposomes was observed which could be attributed to co-crystallization of both compounds. The addition of gamma oryzanol, caused to reduce the melting point of 5% (w/v lecithin-based liposome from 207°C to 163.2°C. At high level of lecithin, increasing of liposome particle size (storage at 4°C for two months was more obvious and particle size increased from 61 and 113 to 283 and 384 nanometers, respectively. The encapsulation efficiency of gamma oryzanol increased from 60% to 84.3% with increasing lecithin content. The encapsulation stability of oryzanol in liposome was determined at different concentrations of lecithin 3, 5, 10, 20% (w/v and different storage times (1, 7, 30 and 60 days. In all concentrations, the encapsulation stability slightly decreased during 30 days storage. The scanning electron microscopy (SEM images showed relatively spherical to elliptic particles which indicated to low extent of particles coalescence. The oscillatory rheometry showed that the loss modulus of liposomes were higher than storage modulus and more liquid-like behavior than solid-like behavior. The samples storage at 25°C for one month, showed higher viscoelastic parameters than those having been stored at 4°C which were attributed to higher membrane fluidity at 25°C and their final coalescence.Nanoliposomes are one of the most important polar lipid based nanocarriers which can be used for encapsulation of both hydrophilic and hydrophobic active compounds. In this research, nanoliposomes based on lecithin-polyethylene glycol-gamma oryzanol were prepared by using modified thermal method. Only one

  6. Ureic nitrogen transformation in multi-layer soil columns treated with urease and nitrification inhibitors.

    Science.gov (United States)

    Giovannini, Camilla; Garcia-Mina, Josè M; Ciavatta, Claudio; Marzadori, Claudio

    2009-06-10

    The use of N-(n-butyl)thiophosphoric triamide (NBPT), as a urease inhibitor, is one of the most successful strategies utilized to increase the efficiency of urea-based fertilization. To date, NBPT has been added to the soil incorporated in fertilizers containing either urea or the inhibitor at a fixed percentage on the urea weight. The possibility of using NBPT physically separated from urea-based fertilizers could make its use more flexible. In particular, a granulated product containing NBPT could be utilized in soils treated with different urea-based fertilizers including livestock urine, the amount depending on soil characteristics and/or the urea source (e.g., mineral fertilizer, organo-mineral fertilizer, or animal slurry). In this study, a multilayer soil column device was used to investigate the influence of an experimental granular product (RV) containing NBPT and a garlic extract, combining the ability to protect NBPT by oxidation and nitrification inhibition activity, on (a) spatial variability of soil urease and nitrification activities and (b) timing of urea hydrolysis and mineral-N form accumulation (NO(2)(-), NO(3)(-), NH(4)(+)) in soil treated with urea. The results clearly demonstrated that RV can, effectively, inhibit the soil urease activity along the soil column profile up to 8-10 cm soil layer depth and that the inhibition power of RV was dependent on time and soil depth. However, nitrification activity is not significantly influenced by RV addition. In addition, the soil N transformations were clearly affected by RV; in fact, RV retarded urea hydrolysis and reduced the accumulation of NH(4)(+)-N and NO(2)(-)-N ions along the soil profile. The RV product was demonstrated to be an innovative additive able to modify some key ureic N trasformation processes correlated with the efficiency of the urea-based fertilization, in a soil column higher than 10 cm.

  7. In situ nuclear magnetic response of permafrost and active layer soil in boreal and tundra ecosystems

    DEFF Research Database (Denmark)

    Kass, Mason Andrew; Irons, Trevor; Minsley, Burke J.

    2017-01-01

    Characterization of permafrost, particularly warm and near-surface permafrost which can contain significant liquid water, is critical to understanding complex interrelationships with climate change, ecosystems, and disturbances such as wildfires. Understanding the vulnerability and resilience...... of the nuclear magnetic resonance (NMR) response of the active layer and permafrost in a variety of soil conditions, types, and saturations. In this paper, we summarize the NMR data and present quantitative relationships between active layer and permafrost liquid water content and pore sizes and show...

  8. How different is the composition of the fouling layer of wastewater reuse and seawater desalination RO membranes?

    KAUST Repository

    Khan, Muhammad; Busch, Markus; Molina, Veró nica Garcí a; Emwas, Abdul-Hamid M.; Aubry, Cyril; Croue, Jean-Philippe

    2014-01-01

    To study the effect of water quality and operating parameters on membrane fouling, a comparative analysis of wastewater (WW) and seawater (SW) fouled reverse osmosis (RO) membranes was conducted. Membranes were harvested from SWRO and WWRO pilot plants located in Vilaseca (East Spain), both using ultrafiltration as pretreatment. The SWRO unit was fed with Mediterranean seawater and the WWRO unit was operated using secondary effluent collected from the municipal wastewater treatment plant. Lead and terminal SWRO and WWRO modules were autopsied after five months and three months of operation, respectively. Ultrastructural, chemical, and microbiological analyses of the fouling layers were performed. Results showed that the WWRO train had mainly bio/organic fouling at the lead position element and inorganic fouling at terminal position element, whereas SWRO train had bio/organic fouling at both end position elements. In the case of WWRO membranes, Betaproteobacteria was the major colonizing species; while Ca, S, and P were the major present inorganic elements. The microbial population of SWRO membranes was mainly represented by Alpha and Gammaproteobacteria. Ca, Fe, and S were the main identified inorganic elements of the fouling layer of SWRO membranes. These results confirmed that the RO fouling layer composition is strongly impacted by the source water quality. © 2014 Elsevier Ltd.

  9. How different is the composition of the fouling layer of wastewater reuse and seawater desalination RO membranes?

    KAUST Repository

    Khan, Muhammad

    2014-08-01

    To study the effect of water quality and operating parameters on membrane fouling, a comparative analysis of wastewater (WW) and seawater (SW) fouled reverse osmosis (RO) membranes was conducted. Membranes were harvested from SWRO and WWRO pilot plants located in Vilaseca (East Spain), both using ultrafiltration as pretreatment. The SWRO unit was fed with Mediterranean seawater and the WWRO unit was operated using secondary effluent collected from the municipal wastewater treatment plant. Lead and terminal SWRO and WWRO modules were autopsied after five months and three months of operation, respectively. Ultrastructural, chemical, and microbiological analyses of the fouling layers were performed. Results showed that the WWRO train had mainly bio/organic fouling at the lead position element and inorganic fouling at terminal position element, whereas SWRO train had bio/organic fouling at both end position elements. In the case of WWRO membranes, Betaproteobacteria was the major colonizing species; while Ca, S, and P were the major present inorganic elements. The microbial population of SWRO membranes was mainly represented by Alpha and Gammaproteobacteria. Ca, Fe, and S were the main identified inorganic elements of the fouling layer of SWRO membranes. These results confirmed that the RO fouling layer composition is strongly impacted by the source water quality. © 2014 Elsevier Ltd.

  10. Theory of the formation of the electric double layer at the ion exchange membrane-solution interface.

    Science.gov (United States)

    Moya, A A

    2015-02-21

    This work aims to extend the study of the formation of the electric double layer at the interface defined by a solution and an ion-exchange membrane on the basis of the Nernst-Planck and Poisson equations, including different values of the counter-ion diffusion coefficient and the dielectric constant in the solution and membrane phases. The network simulation method is used to obtain the time evolution of the electric potential, the displacement electric vector, the electric charge density and the ionic concentrations at the interface between a binary electrolyte solution and a cation-exchange membrane with total co-ion exclusion. The numerical results for the temporal evolution of the interfacial electric potential and the surface electric charge are compared with analytical solutions derived in the limit of the shortest times by considering the Poisson equation for a simple cationic diffusion process. The steady-state results are justified from the Gouy-Chapman theory for the diffuse double layer in the limits of similar and high bathing ionic concentrations with respect to the fixed-charge concentration inside the membrane. Interesting new physical insights arise from the interpretation of the process of the formation of the electric double layer at the ion exchange membrane-solution interface on the basis of a membrane model with total co-ion exclusion.

  11. Ultrathin Graphene Membranes as Flexible Electrodes for Electrochemical Double Layer Capacitors

    Science.gov (United States)

    Talapatra, Saikat; Kar, Swastik; Shah, Rakesh; Ghosh, Sujoy; An, Xiaohong; Simmons, Trevor; Washington, Morris; Nayak, Saroj

    2010-03-01

    We will present the results of our investigations of electrochemical double layer capacitors (EDLCs) or supercapacitors (SC) fabricated using graphene based ultra thin membranes. These EDLC's show far superior performance compared to other carbon nanomaterials based EDLC's devices. We found that the graphene based devices possess specific capacitance values as high as 120 F/g, with impressive power densities (˜105 kW/kg) and energy densities (˜9.2 Wh/kg). Further, these devices indicated rapid charge transfer response even without the use of any binders or specially prepared current collectors. Our ultracapacitors reflect a significant improvement over previously reported graphene-based ultracapacitors and are substantially better than those obtained with carbon nanotubes.

  12. Liquid water breakthrough location distances on a gas diffusion layer of polymer electrolyte membrane fuel cells

    Science.gov (United States)

    Yu, Junliang; Froning, Dieter; Reimer, Uwe; Lehnert, Werner

    2018-06-01

    The lattice Boltzmann method is adopted to simulate the three dimensional dynamic process of liquid water breaking through the gas diffusion layer (GDL) in the polymer electrolyte membrane fuel cell. 22 micro-structures of Toray GDL are built based on a stochastic geometry model. It is found that more than one breakthrough locations are formed randomly on the GDL surface. Breakthrough location distance (BLD) are analyzed statistically in two ways. The distribution is evaluated statistically by the Lilliefors test. It is concluded that the BLD can be described by the normal distribution with certain statistic characteristics. Information of the shortest neighbor breakthrough location distance can be the input modeling setups on the cell-scale simulations in the field of fuel cell simulation.

  13. Electrodeposition to construct free-standing chitosan/layered double hydroxides hydro-membrane for electrically triggered protein release.

    Science.gov (United States)

    Zhao, Pengkun; Zhao, Yanan; Xiao, Ling; Deng, Hongbing; Du, Yumin; Chen, Yun; Shi, Xiaowen

    2017-10-01

    In this study, we report the electrodeposition of a chitosan/layered double hydroxides (LDHs) hydro-membrane for protein release triggered by an electrical signal. The electrodeposition was performed in a chitosan and insulin loaded LDHs suspension in the absence of salt. A free-standing chitosan/LDHs hydro-membrane was generated on the electrode with improved mechanical properties, which is dramatically different from the weak hydrogel deposited in the presence of salt. The amount of LDHs in the hydro-membrane affects the optical transmittance and multilayered structure of the hybrid membrane. Compared to the weak chitosan/LDHs hydrogel, the hydro-membrane has a higher insulin loading capacity and the release of insulin is relatively slow. By biasing electrical potentials to the hydro-membrane, the release behavior of insulin can be adjusted accordingly. In addition, the chitosan/LDHs hydro-membrane showed no toxicity to cells. Our results provide a facile method to construct a chitosan/LDHs hybrid multilayered hydro-membrane and suggest the great potential of the hydro-membrane in controlled protein release. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. In-situ Growth of Biocidal AgCl Crystals in the Top Layer of Asymmetric Polytriazole Membranes

    KAUST Repository

    Villalobos, Luis Francisco; Chisca, Stefan; Cheng, Hong; Hong, Pei-Ying; Nunes, Suzana Pereira; Peinemann, Klaus-Viktor

    2016-01-01

    Scalable fabrication strategies to concentrate biocidal materials in only the surface of membranes are highly desirable. In this letter, tight-UF polytriazole membranes with a high concentration of biocide silver chloride (AgCl) crystals dispersed in only their top layer are presented. They were made following a simple dual-bath process that is compatible with current commercial membrane casting facilities. These membranes can achieve a 150-fold increase in their antimicrobial character compared to their silver-free counterpart. Moreover, fine-tuning of their properties is straightforward. A change in the silver concentration in one of the baths is enough to tune the permeance, molecular weight cut-off (MWCO) and silver loading of the final membrane.

  15. In-situ Growth of Biocidal AgCl Crystals in the Top Layer of Asymmetric Polytriazole Membranes

    KAUST Repository

    Villalobos, Luis Francisco

    2016-05-06

    Scalable fabrication strategies to concentrate biocidal materials in only the surface of membranes are highly desirable. In this letter, tight-UF polytriazole membranes with a high concentration of biocide silver chloride (AgCl) crystals dispersed in only their top layer are presented. They were made following a simple dual-bath process that is compatible with current commercial membrane casting facilities. These membranes can achieve a 150-fold increase in their antimicrobial character compared to their silver-free counterpart. Moreover, fine-tuning of their properties is straightforward. A change in the silver concentration in one of the baths is enough to tune the permeance, molecular weight cut-off (MWCO) and silver loading of the final membrane.

  16. Dynamics and characteristics of soil temperature and moisture of active layer in central Tibetan Plateau

    Science.gov (United States)

    Zhao, L.; Hu, G.; Wu, X.; Tian, L.

    2017-12-01

    Research on the hydrothermal properties of active layer during the thawing and freezing processes was considered as a key question to revealing the heat and moisture exchanges between permafrost and atmosphere. The characteristics of freezing and thawing processes at Tanggula (TGL) site in permafrost regions on the Tibetan Plateau, the results revealed that the depth of daily soil temperature transmission was about 40 cm shallower during thawing period than that during the freezing period. Soil warming process at the depth above 140 cm was slower than the cooling process, whereas they were close below 140 cm depth. Moreover, the hydro-thermal properties differed significantly among different stages. Precipitation caused an obviously increase in soil moisture at 0-20 cm depth. The vertical distribution of soil moisture could be divided into two main zones: less than 12% in the freeze state and greater than 12% in the thaw state. In addition, coupling of moisture and heat during the freezing and thawing processes also showed that soil temperature decreased faster than soil moisture during the freezing process. At the freezing stage, soil moisture exhibited an exponential relationship with the absolute soil temperature. Energy consumed for water-ice conversion during the freezing process was 149.83 MJ/m2 and 141.22 MJ/m2 in 2011 and 2012, respectively, which was estimated by the soil moisture variation.

  17. Analysis of proton exchange membrane fuel cell catalyst layers for reduction of platinum loading at Nissan

    International Nuclear Information System (INIS)

    Ohma, Atsushi; Mashio, Tetsuya; Sato, Kazuyuki; Iden, Hiroshi; Ono, Yoshitaka; Sakai, Kei; Akizuki, Ken; Takaichi, Satoshi; Shinohara, Kazuhiko

    2011-01-01

    The biggest issue that must be addressed in promoting widespread use of fuel cell vehicles (FCVs) is to reduce the cost of the fuel cell system. Especially, it is of vital importance to reduce platinum (Pt) loading of catalyst layers (CLs) in the membrane electrode assembly (MEA) of a proton exchange membrane fuel cell (PEMFC). In order to lower the Pt loading of the MEA, mass transport of reactants related to the performance in high current density should be enhanced significantly as well as kinetics of the catalyst, which can result in the better Pt utilization and effectiveness. In this study, we summarized our analytical approach and methods for reduction of Pt loading in CLs. Microstructure, mass transport properties of the reactants, and their relation in CLs were elucidated by applying experimental analyses and computational methods. A simple CL model for I–V performance prediction was then established, where experimentally elucidated parameters of the microstructure and the properties in CLs were taken into account. Finally, we revealed the impact of lowering the Pt loading on the transport properties, polarization, and the I–V performance.

  18. Gas diffusion layer for proton exchange membrane fuel cells - A review

    Energy Technology Data Exchange (ETDEWEB)

    Cindrella, L. [Fuel Cell Research Laboratory, Department of Engineering Technology, Arizona State University, Mesa, AZ 85212 (United States); Department of Chemistry, National Institute of Technology, Tiruchirappalli 620015 (India); Kannan, A.M.; Lin, J.F.; Saminathan, K. [Fuel Cell Research Laboratory, Department of Engineering Technology, Arizona State University, Mesa, AZ 85212 (United States); Ho, Y. [Department of Biotechnology, College of Health Science, Asia University, Taichung 41354 (China); Lin, C.W. [Department of Chemical Engineering, National Yunlin University of Science and Technology, Yunlin 640 (China); Wertz, J. [Hollingsworth and Vose Co., A.K. Nicholson Research Lab, 219 Townsend Road, West Groton, MA 01472 (United States)

    2009-10-20

    Gas diffusion layer (GDL) is one of the critical components acting both as the functional as well as the support structure for membrane-electrode assembly in the proton exchange membrane fuel cell (PEMFC). The role of the GDL is very significant in the H{sub 2}/air PEM fuel cell to make it commercially viable. A bibliometric analysis of the publications on the GDLs since 1992 shows a total of 400+ publications (>140 papers in the Journal of Power Sources alone) and reveals an exponential growth due to reasons that PEMFC promises a lot of potential as the future energy source for varied applications and hence its vital component GDL requires due innovative analysis and research. This paper is an attempt to pool together the published work on the GDLs and also to review the essential properties of the GDLs, the method of achieving each one of them, their characterization and the current status and future directions. The optimization of the functional properties of the GDLs is possible only by understanding the role of its key parameters such as structure, porosity, hydrophobicity, hydrophilicity, gas permeability, transport properties, water management and the surface morphology. This paper discusses them in detail to provide an insight into the structural parts that make the GDLs and also the processes that occur in the GDLs under service conditions and the characteristic properties. The required balance in the properties of the GDLs to facilitate the counter current flow of the gas and water is highlighted through its characteristics. (author)

  19. Structural Study and Modification of Support Layer for Forward Osmosis Membranes

    KAUST Repository

    Shi, Meixia

    2016-01-01

    polymerization. Among the different substrates we include standard asymmetric porous membranes prepared from homopolymers, such as polysulfone. Additionally block copolymer membrane and Anodisc alumina membrane are chosen based on their exceptional structures

  20. Pressure retarded osmosis dual-layer hollow fiber membranes developed by co-casting method and ammonium persulfate (APS) treatment

    KAUST Repository

    Fu, Fengjiang; Sun, Shipeng; Zhang, Sui; Chung, Neal Tai-Shung

    2014-01-01

    Delamination and low water permeability are two issues limiting the applications of dual-layer hollow fiber membranes in the pressure retarded osmosis (PRO) process. In this work, we first developed a universal co-casting method that is able to co-cast highly viscous dope solutions to form homogeneous dual-layer flat sheet membranes. By employing this method prior to the tedious dual-layer hollow fiber spinning process, both time and material consumptions are significantly saved. The addition of polyvinylpyrrolidone (PVP) is found to eliminate delamination at the sacrifice of water flux. A new post-treatment method that involves flowing ammonium persulfate (APS) solution and DI water counter-currently is potentially to remove the PVP molecules entrapped in the substrate while keeps the integrity of the interface. As the APS concentration increases, the water flux in the PRO process is increased while the salt leakage is slightly decreased. With the optimized APS concentration of 5wt%, the post-treated membrane shows a maximum power density of 5.10W/m2 at a hydraulic pressure of 15.0bar when 1M NaCl and 10mM NaCl were used as the draw and feed solutions, respectively. To the extent of our knowledge, this is the best phase inversion dual-layer hollow fiber membrane with an outer selective layer for osmotic power generation. © 2014 Elsevier B.V.

  1. Pressure retarded osmosis dual-layer hollow fiber membranes developed by co-casting method and ammonium persulfate (APS) treatment

    KAUST Repository

    Fu, Fengjiang

    2014-11-01

    Delamination and low water permeability are two issues limiting the applications of dual-layer hollow fiber membranes in the pressure retarded osmosis (PRO) process. In this work, we first developed a universal co-casting method that is able to co-cast highly viscous dope solutions to form homogeneous dual-layer flat sheet membranes. By employing this method prior to the tedious dual-layer hollow fiber spinning process, both time and material consumptions are significantly saved. The addition of polyvinylpyrrolidone (PVP) is found to eliminate delamination at the sacrifice of water flux. A new post-treatment method that involves flowing ammonium persulfate (APS) solution and DI water counter-currently is potentially to remove the PVP molecules entrapped in the substrate while keeps the integrity of the interface. As the APS concentration increases, the water flux in the PRO process is increased while the salt leakage is slightly decreased. With the optimized APS concentration of 5wt%, the post-treated membrane shows a maximum power density of 5.10W/m2 at a hydraulic pressure of 15.0bar when 1M NaCl and 10mM NaCl were used as the draw and feed solutions, respectively. To the extent of our knowledge, this is the best phase inversion dual-layer hollow fiber membrane with an outer selective layer for osmotic power generation. © 2014 Elsevier B.V.

  2. Acute epidural-like appearance of an encapsulated solid non-organized chronic subdural hematoma.

    Science.gov (United States)

    Prieto, Ruth; Pascual, José M; Subhi-Issa, Issa; Yus, Miguel

    2010-01-01

    We report the exceptional case of an encapsulated solid non-organized chronic subdural hematoma (SDH) in a 67-year-old woman that was admitted with acute hemiplegia followed by rapid deterioration in consciousness 5 months after a minor head trauma. Computed tomography (CT) showed an extracerebral biconvex shaped hyperdense mass that led to the misdiagnosis of an acute epidural hematoma. Urgent craniotomy revealed an encapsulated mass filled with solid fresh clot in the subdural space. Complete evacuation of this SDH, including both its inner and outer membranes, was achieved, and the patient recovered successfully. Histological analysis confirmed that the content of the hematoma corresponded to a newly formed clot that was enclosed between an inner membrane, composed of two collagen layers, and an outer membrane with a three layered structure. Chronic SDH may seldom present as an encapsulated solid non-organized lesion that consists of a fibrous capsule enclosing a fresh clot and lacking the thick fibrous septations that typically connect the inner and outer membranes of organized chronic SDH. This entity mimics the clinical course and radiological appearance of acute epidural hematomas and should be considered in the differential diagnosis of extracerebral hyperdense biconvex shaped lesions.

  3. Bearing Capacity of Footings on Thin Layer of Sand on Soft Cohesive Soil

    DEFF Research Database (Denmark)

    Philipsen, J.; Sørensen, Carsten S.

    2004-01-01

    This paper contains the results of some numerical calculations performed with the aim to determine the bearing capacities of footings placed on a thin layer of sand underlain by soft cohesive soil. During the last 30-35 years different analytical and empirical calculation methods for this situation...... prepared model tests made in laboratories....

  4. Bryoid layer response to soil disturbance by fuel reduction treatments in a dry conifer forest

    Science.gov (United States)

    Amanda Hardman; Bruce McCune

    2010-01-01

    We investigated the response of the bryoid layer, bryophyte and lichen communities on the soil surface three years after fuel reduction treatment (logging and burning) in the central Blue Mountains of eastern Oregon. Both treatment and control areas had been decimated by spruce budworm and drought before the fuel reduction treatments. Treatments reduced overstory and...

  5. Thin layer chromatographic analyses of pesticides in a soil ecosystem

    International Nuclear Information System (INIS)

    Afful, S.; Dogbe, S.A.; Ahmad, K.; Ewusie, A.T.

    2008-01-01

    Silica gel 60, silica gel 60 F 254 , and aluminium oxide as adsorbents were used to investigate their suitability for the analysis and detection of the pesticides: nitrofen, atrazine, diuron, dioxacarb, propoxur, propanil, carbaryl and cypermethrin in soil ecosystem using ethyl acetate, chloroform, dichloromethane and ethyl acetate/chloroform (1:1) as developing solvents. O-tolidine and potassium iodide reagent were used for the detection of pesticides. R f values obtained for the pesticides using the silica gel 60-ethyl acetate. silica gel 60F 254 -ethyl acetate, silica gel 60 chloroform, silica gel 60 F 254 - chloroform, silica gel 60 - (1:1) ethyl acetate/chloroform and silica gel 60 F 254 - (1:1) ethyl acetate/chloroform systems generally were within the stipulated range of 0.4-0.8. R f values obtained for the pesticides using silica gel 60-dichloromethane systems were very low except for cypermethrin and nitrofen. Analysis with aluminium oxide coated plates gave a heavy yellow background with the detection reagent making visualization of spots difficult. Aluminium oxide coated plate is, therefore, not recommended when o-tolidine plus potassium iodide is used as detection reagent. (au)

  6. KIN SP: A boundary element method based code for single pile kinematic bending in layered soil

    Directory of Open Access Journals (Sweden)

    Stefano Stacul

    2018-02-01

    Full Text Available In high seismicity areas, it is important to consider kinematic effects to properly design pile foundations. Kinematic effects are due to the interaction between pile and soil deformations induced by seismic waves. One of the effect is the arise of significant strains in weak soils that induce bending moments on piles. These moments can be significant in presence of a high stiffness contrast in a soil deposit. The single pile kinematic interaction problem is generally solved with beam on dynamic Winkler foundation approaches (BDWF or using continuous models. In this work, a new boundary element method (BEM based computer code (KIN SP is presented where the kinematic analysis is preceded by a free-field response analysis. The analysis results of this method, in terms of bending moments at the pile-head and at the interface of a two-layered soil, are influenced by many factors including the soil–pile interface discretization. A parametric study is presented with the aim to suggest the minimum number of boundary elements to guarantee the accuracy of a BEM solution, for typical pile–soil relative stiffness values as a function of the pile diameter, the location of the interface of a two-layered soil and of the stiffness contrast. KIN SP results have been compared with simplified solutions in literature and with those obtained using a quasi-three-dimensional (3D finite element code.

  7. Occurrence and distribution of tetraether membrane lipids in soils: implications for the use of the TEX86 proxy and the BIT index

    NARCIS (Netherlands)

    Weijers, J.W.H.; Schouten, S.; Spaargaren, O.C.; Sinnige Damsté, J.S.

    2006-01-01

    A diverse collection of globally distributed soil samples was analyzed for its glycerol dialkyl glycerol tetraether (GDGT) membrane lipid content. Branched GDGTs, derived from anaerobic soil bacteria, were the most dominant and were found in all soils. Isoprenoid GDGTs, membrane lipids of Archaea,

  8. Nanoporous Aluminum Oxide Membranes Coated with Atomic Layer Deposition-Grown Titanium Dioxide for Biomedical Applications: An In Vitro Evaluation.

    Science.gov (United States)

    Petrochenko, Peter E; Kumar, Girish; Fu, Wujun; Zhang, Qin; Zheng, Jiwen; Liang, Chengdu; Goering, Peter L; Narayan, Roger J

    2015-12-01

    The surface topographies of nanoporous anodic aluminum oxide (AAO) and titanium dioxide (TiO2) membranes have been shown to modulate cell response in orthopedic and skin wound repair applications. In this study, we: (1) demonstrate an improved atomic layer deposition (ALD) method for coating the porous structures of 20, 100, and 200 nm pore diameter AAO with nanometer-thick layers of TiO2 and (2) evaluate the effects of uncoated AAO and TiO2-coated AAO on cellular responses. The TiO2 coatings were deposited on the AAO membranes without compromising the openings of the nanoscale pores. The 20 nm TiO2-coated membranes showed the highest amount of initial protein adsorption via the micro bicinchoninic acid (micro-BCA) assay; all of the TiO2-coated membranes showed slightly higher protein adsorption than the uncoated control materials. Cell viability, proliferation, and inflammatory responses on the TiO2-coated AAO membranes showed no adverse outcomes. For all of the tested surfaces, normal increases in proliferation (DNA content) of L929 fibroblasts were observed over from 4 hours to 72 hours. No increases in TNF-alpha production were seen in RAW 264.7 macrophages grown on TiO2-coated AAO membranes compared to uncoated AAO membranes and tissue culture polystyrene (TCPS) surfaces. Both uncoated AAO membranes and TiO2-coated AAO membranes showed no significant effects on cell growth and inflammatory responses. The results suggest that TiO2-coated AAO may serve as a reasonable prototype material for the development of nanostructured wound repair devices and orthopedic implants.

  9. Membrane proteins involved in transport, vesicle traffic and Ca(2+) signaling increase in beetroots grown in saline soils.

    Science.gov (United States)

    Lino, Bárbara; Chagolla, Alicia; E González de la Vara, Luis

    2016-07-01

    By separating plasma membrane proteins according to their hydropathy from beetroots grown in saline soils, several proteins probably involved in salt tolerance were identified by mass spectrometry. Beetroots, as a salt-tolerant crop, have developed mechanisms to cope with stresses associated with saline soils. To observe which plasma membrane (PM) proteins were more abundant in beet roots grown in saline soils, beet root plants were irrigated with water or 0.2 M NaCl. PM-enriched membrane preparations were obtained from these plants, and their proteins were separated according to their hydropathy by serial phase partitioning with Triton X-114. Some proteins whose abundance increased visibly in membranes from salt-grown beetroots were identified by mass spectrometry. Among them, there was a V-type H(+)-ATPase (probably from contaminating vacuolar membranes), which increased with salt at all stages of beetroots' development. Proteins involved in solute transport (an H(+)-transporting PPase and annexins), vesicle traffic (clathrin and synaptotagmins), signal perception and transduction (protein kinases and phospholipases, mostly involved in calcium signaling) and metabolism, appeared to increase in salt-grown beetroot PM-enriched membranes. These results suggest that PM and vacuolar proteins involved in transport, metabolism and signal transduction increase in beet roots adapted to saline soils. In addition, these results show that serial phase partitioning with Triton X-114 is a useful method to separate membrane proteins for their identification by mass spectrometry.

  10. The human periodontal membrane: focusing on the spatial interrelation between the epithelial layer of Malassez, fibers, and innervation

    DEFF Research Database (Denmark)

    Kjaer, Inger; Nolting, Dorrit

    2009-01-01

    OBJECTIVE: The purpose of the present study was to map the spatial interrelation of fibers, peripheral nerves, and epithelial layer of Malassez in human periodontal membrane in areas close to the root surfaces. MATERIAL AND METHODS: Four healthy permanent teeth extracted from four patients during...

  11. Well-constructed cellulose acetate membranes for forward osmosis: Minimized internal concentration polarization with an ultra-thin selective layer

    KAUST Repository

    Zhang, Sui; Wang, Kaiyu; Chung, Tai Shung Neal; Chen, Hongmin; Jean, Yanching; Amy, Gary L.

    2010-01-01

    polarization (ECP) and ICP, and the St value of the double dense-layer membrane is much smaller than those reported in literatures. Furthermore, the effects of an intermediate immersion into a solvent/water mixed bath prior to complete immersion in water

  12. Soil and surface layer type affect non-rainfall water inputs

    Science.gov (United States)

    Agam, Nurit; Berliner, Pedro; Jiang, Anxia

    2017-04-01

    Non-rainfall water inputs (NRWIs), which include fog deposition, dew formation, and direct water vapor adsorption by the soil, play a vital role in arid and semiarid regions. Environmental conditions, namely radiation, air temperature, air humidity, and wind speed, largely affect the water cycle driven by NRWIs. The substrate type (soil type and the existence/absence of a crust layer) may as well play a major role. Our objective was to quantify the effects of soil type (loess vs. sand) and surface layer (bare vs. crusted) on the gain and posterior evaporation of NRWIs in the Negev Highlands throughout the dry summer season. Four undisturbed soil samples (20 cm diameter and 50 cm depth) were excavated and simultaneously introduced into a PVC tube. Two samples were obtained in the Negev's Boker plain (loess soil) and two in the Nizzana sand dunes in the Western Negev. On one sample from each site the crust was removed while on the remaining one the natural crust was left in place. The samples were brought to the research site at the Jacob Bluestein Institutes for Desert Research, Ben-Gurion University of the Negev, Israel (31˚08' N, 34˚53' E, 400 meter above the sea level) where they were exposed to the same environmental conditions. The four samples in their PVC tubes were placed on top of scales and the samples mass was continuously monitored. Soil temperatures were monitored at depths of 1, 2, 3, 5 and10 cm in each microlysimeter (ML) using Copper-Constantan thermocouples. The results of particle size distribution indicated that the crust of the loess soil is probably a physical crust, i.e., a crust that forms due to raindroplets impact; while the crust on the sand soil is biological. On most days, the loess soils adsorbed more water than their corresponding sand soil samples. For both soils, the samples for which the crust was removed adsorbed more water than the samples for which it was intact. The difference in daily water adsorption amount between crusted

  13. Mechanical properties and osteogenic activity of poly(l-lactide) fibrous membrane synergistically enhanced by chitosan nanofibers and polydopamine layer.

    Science.gov (United States)

    Liu, Hua; Li, Wenling; Wen, Wei; Luo, Binghong; Liu, Mingxian; Ding, Shan; Zhou, Changren

    2017-12-01

    To synergistically improve the mechanical properties and osteogenic activity of electrospinning poly(l-lactide) (PLLA) membrane, chitosan (CS) nanofibers were firstly introduced to prepare sub-micro and nanofibers interpenetrated PLLA/CS membrane, which was further surface modified with a polydopamine (PDA) layer to obtain PLLA/CS-PDA. Surface morphology, porosity, surface area and hydrophilicity of the obtained fibrous membranes were studied in detail. As compared to pure PLLA, the significant increase in the mechanical properties of the PLLA/CS, and especially of the PLLA/CS-PDA, was confirmed by tensile testing both in dry and wet states. Cells culture results indicated that both the PLLA/CS and PLLA/CS-PDA membranes, especially the latter, were more beneficial to adhesion, spreading and proliferation, as well as up-regulating alkaline phosphate activity and calcium deposition of MC3T3-E1 cells than PLLA membrane. Results suggested there was a synergistic effect of the CS nanofibers and PDA layer on the mechanical properties and osteogenic activity of PLLA membrane. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Ameliorating effects of designer biochars in a hard-setting subsoil layer: soil fertility and plant biomass

    Science.gov (United States)

    Soils in the southeastern U.S. Coastal Plain region have meager soil fertility and frequently have compacted subsoil layers (E horizon). Designer biochar has gained global interest as an amendment to improve the fertility, chemical, and physical properties of degraded agricultural soils. We hypothes...

  15. Interaction of Peat Soil and Sulphidic Material Substratum: Role of Peat Layer and Groundwater Level Fluctuations on Phosphorus Concentration

    Directory of Open Access Journals (Sweden)

    Benito Heru Purwanto

    2014-09-01

    Full Text Available Phosphorus (P often becomes limiting factor for plants growth. Phosphorus geochemistry in peatland soil is associated with the presence of peat layer and groundwater level fluctuations. The research was conducted to study the role of peat layer and groundwater level fluctuations on P concentration in peatland. The research was conducted on deep, moderate and shallow peat with sulphidic material as substratum, peaty acid sulphate soil, and potential acid sulphate soil. While P concentration was observed in wet season, in transition from wet to dry season, and in dry season. Soil samples were collected by using peat borer according to interlayer and soil horizon. The results showed that peat layer might act as the main source of P in peatland with sulphidic material substratum. The upper peat layer on sulphidic material caused by groundwater level fluctuations had no directly effect on P concentration in the peat layers. Increased of P concentration in the lowest sulphidic layer might relate to redox reaction of iron in the sulphidic layer and precipitation process. Phosphorus concentration in peatland with sulphidic material as substratum was not influenced by peat thickness. However, depletion or disappearance of peat layer decreased P concentration in soil solution. Disappearance of peat layer means loss of a natural source of P for peatland with sulphidic material as substratum, therefore peat layer must be kept in order to maintain of peatlands.

  16. Research on the Horizontal Displacement Coefficient of Soil Surrounding Pile in Layered Foundations by Considering the Soil Mass’s Longitudinal Continuity

    Directory of Open Access Journals (Sweden)

    Yao Wen-Juan

    2013-01-01

    Full Text Available When utilizing the p-y curve to simulate the nonlinear characteristics of soil surrounding pile in layered foundations, due to having not taken into account the soil mass’s longitudinal continuity, the calculation deviation of horizontal displacement increases with the growth of a load. This paper adopted the layered elasticity system theory to consider the soil mass’s longitudinal continuity, as well as utilizing the research method for layered isotropic bodies, assuming that the horizontal resistance is evenly distributed around the perimeter of the pile's cross-section. Then an appropriate transfer matrix method of horizontal displacement coefficient for the soil surrounding pile in layered foundations was established. According to the calculation principle of finite element equivalent load, the horizontal displacement coefficient matrix was deduced as well as providing a corrected formula for the horizontal displacement of soil surrounding pile through the p-y curve method when the external load was increased. Following the established model, a program was created which was used for calculating and analyzing the horizontal displacement coefficient matrix of three-layered soil in order to verify this method’s validity and rationale. Where there is a relatively large discrepancy in the soil layers’ properties, this paper’s method is able to reflect the influence on the layered soil’s actual distributional difference as well as the nearby soil layers’ interaction.

  17. Theoretical Modeling and Analysis of L- and P-band Radar Backscatter Sensitivity to Soil Active Layer Dielectric Variations

    Directory of Open Access Journals (Sweden)

    Jinyang Du

    2015-07-01

    Full Text Available Freeze-thaw (FT and moisture dynamics within the soil active layer are critical elements of boreal, arctic and alpine ecosystems, and environmental change assessments. We evaluated the potential for detecting dielectric changes within different soil layers using combined L- and P-band radar remote sensing as a prerequisite for detecting FT and moisture profile changes within the soil active layer. A two-layer scattering model was developed and validated for simulating radar responses from vertically inhomogeneous soil. The model simulations indicated that inhomogeneity in the soil dielectric profile contributes to both L- and P-band backscatter, but with greater P-band sensitivity at depth. The difference in L- and P-band responses to soil dielectric profile inhomogeneity appears suitable for detecting associated changes in soil active layer conditions. Additional evaluation using collocated airborne radar (AIRSAR observations and in situ soil moisture measurements over alpine tundra indicates that combined L- and P-band SAR observations are sensitive to soil dielectric profile heterogeneity associated with variations in soil moisture and FT conditions.

  18. Transport Asymmetry of Novel Bi-Layer Hybrid Perfluorinated Membranes on the Base of MF-4SC Modified by Halloysite Nanotubes with Platinum

    Directory of Open Access Journals (Sweden)

    Anatoly Filippov

    2018-03-01

    Full Text Available Three types of bi-layer hybrid nanocomposites on the base of perfluorinated cation-exchange membrane MF-4SC (Russian analogue of Nafion®-117 were synthesized and characterized. It was found that two membranes possess the noticeable asymmetry of the current–voltage curve (CVC under changing their orientation towards the applied electric field, despite the absence of asymmetry of diffusion permeability. These phenomena were explained in the frame of the “fine-porous model” expanded for bi-layer membranes. A special procedure to calculate the real values of the diffusion layers thickness and the limiting current density was proposed. Due to asymmetry effects of the current voltage curves of bi-layer hybrid membranes on the base of MF-4SC, halloysite nanotubes and platinum nanoparticles, it is prospective to assemble membrane switches (membrane relays or diodes with predictable transport properties, founded upon the theory developed here.

  19. Observing the morphology of single-layered embedded silicon nanocrystals by using temperature-stable TEM membranes

    Directory of Open Access Journals (Sweden)

    Sebastian Gutsch

    2015-04-01

    Full Text Available We use high-temperature-stable silicon nitride membranes to investigate single layers of silicon nanocrystal ensembles by energy filtered transmission electron microscopy. The silicon nanocrystals are prepared from the precipitation of a silicon-rich oxynitride layer sandwiched between two SiO2 diffusion barriers and subjected to a high-temperature annealing. We find that such single layers are very sensitive to the annealing parameters and may lead to a significant loss of excess silicon. In addition, these ultrathin layers suffer from significant electron beam damage that needs to be minimized in order to image the pristine sample morphology. Finally we demonstrate how the silicon nanocrystal size distribution develops from a broad to a narrow log-normal distribution, when the initial precipitation layer thickness and stoichiometry are below a critical value.

  20. Soil biota and upper soil layer development in two contrasting post-mining chronosequences

    Czech Academy of Sciences Publication Activity Database

    Frouz, Jan; Keplin, B.; Pižl, Václav; Tajovský, Karel; Starý, Josef; Lukešová, Alena; Nováková, Alena; Balík, Vladimír; Háněl, Ladislav; Materna, Jan; Düker, Ch.; Chalupský, Josef; Rusek, Josef; Heinkele, T.

    2001-01-01

    Roč. 17, - (2001), s. 275-284 ISSN 0925-8574 R&D Projects: GA MŠk ME 076; GA ČR GA526/98/P156 Institutional research plan: CEZ:AV0Z6066911 Keywords : succession * coal mining * soil formation Subject RIV: EH - Ecology, Behaviour Impact factor: 0.601, year: 2001

  1. Effect of hydrophobic additive on oxygen transport in catalyst layer of proton exchange membrane fuel cells

    Science.gov (United States)

    Wang, Shunzhong; Li, Xiaohui; Wan, Zhaohui; Chen, Yanan; Tan, Jinting; Pan, Mu

    2018-03-01

    Oxygen transport resistance (OTR) is a critical factor influencing the performance of proton exchange membrane fuel cells (PEMFCs). In this paper, an effective method to reduce the OTR of catalyst layers (CLs) by introducing a hydrophobic additive into traditional CLs is proposed. A low-molecular-weight polytetrafluoroethylene (PTFE) is selected for its feasibility to prepare an emulsion, which is mixed with a traditional catalyst ink to successfully fabricate the CL with PTFE of 10 wt%. The PTFE film exists in the mesopores between the carbon particles. The limiting current of the hydrophobic CL was almost 4000 mA/cm2, which is 500 mA/cm2 higher than that of the traditional CL. PTFE reduces the OTR of the CL in the dry region by as much as 24 s/m compared to the traditional CL and expands the dry region from 2000 mA/cm2 in the traditional CL to 2500 mA/cm2. Furthermore, the CL with the hydrophobic agent can improve the oxygen transport in the wet region (>2000 mA/cm2) more effectively than that in the dry region. All these results indicate that the CL with the hydrophobic agent shows a superior performance in terms of optimizing water management and effectively reduces the OTR in PEMFCs.

  2. Thermal conductivity of catalyst layer of polymer electrolyte membrane fuel cells: Part 1 - Experimental study

    Science.gov (United States)

    Ahadi, Mohammad; Tam, Mickey; Saha, Madhu S.; Stumper, Jürgen; Bahrami, Majid

    2017-06-01

    In this work, a new methodology is proposed for measuring the through-plane thermal conductivity of catalyst layers (CLs) in polymer electrolyte membrane fuel cells. The proposed methodology is based on deconvolution of bulk thermal conductivity of a CL from measurements of two thicknesses of the CL, where the CLs are sandwiched in a stack made of two catalyst-coated substrates. Effects of hot-pressing, compression, measurement method, and substrate on the through-plane thermal conductivity of the CL are studied. For this purpose, different thicknesses of catalyst are coated on ethylene tetrafluoroethylene (ETFE) and aluminum (Al) substrates by a conventional Mayer bar coater and measured by scanning electron microscopy (SEM). The through-plane thermal conductivity of the CLs is measured by the well-known guarded heat flow (GHF) method as well as a recently developed transient plane source (TPS) method for thin films which modifies the original TPS thin film method. Measurements show that none of the studied factors has any effect on the through-plane thermal conductivity of the CL. GHF measurements of a non-hot-pressed CL on Al yield thermal conductivity of 0.214 ± 0.005 Wṡm-1ṡK-1, and TPS measurements of a hot-pressed CL on ETFE yield thermal conductivity of 0.218 ± 0.005 Wṡm-1ṡK-1.

  3. Fabrication of In Vitro Cancer Microtissue Array on Fibroblast-Layered Nanofibrous Membrane by Inkjet Printing

    Directory of Open Access Journals (Sweden)

    Tae-Min Park

    2017-11-01

    Full Text Available In general, a drug candidate is evaluated using 2D-cultured cancer cells followed by an animal model. Despite successful preclinical testing, however, most drugs that enter human clinical trials fail. The high failure rates are mainly caused by incompatibility between the responses of the current models and humans. Here, we fabricated a cancer microtissue array in a multi-well format that exhibits heterogeneous and batch-to-batch structure by continuous deposition of collagen-suspended Hela cells on a fibroblast-layered nanofibrous membrane via inkjet printing. Expression of both Matrix Metalloproteinase 2 (MMP2 and Matrix Metalloproteinase 9 (MMP9 was higher in cancer microtissues than in fibroblast-free microtissues. The fabricated microtissues were treated with an anticancer drug, and high drug resistance to doxorubicin occurred in cancer microtissues but not in fibroblast-free microtissues. These results introduce an inkjet printing fabrication method for cancer microtissue arrays, which can be used for various applications such as early drug screening and gradual 3D cancer studies.

  4. Study on hydrophobicity degradation of gas diffusion layer in proton exchange membrane fuel cells

    International Nuclear Information System (INIS)

    Yu, Shuchun; Li, Xiaojin; Li, Jin; Liu, Sa; Lu, Wangting; Shao, Zhigang; Yi, Baolian

    2013-01-01

    Highlights: • The hydrophobicity degradation mechanism of GDL was proposed thoroughly. • C-O and C=O groups appeared on the surfaces of GDL after immersion. • The relative content of PTFE in GDL decreased after immersion. • The surfaces and inner structure of GDL destroyed after immersion. - Abstract: As one of the essential components of proton exchange membrane fuel cell (PEMFC), gas diffusion layer (GDL) is of importance on water management, as well on the performance and durability of PEMFC. In this paper, the hydrophobicity degradation of GDL was investigated by immersing it in the 1.0 mol L −1 H 2 SO 4 solution saturated by air for 1200 h. From the measurements of contact angle and water permeability, the hydrophobic characteristics of the pristine and immersed GDLs were compared. To investigate the causes for hydrophobicity degradation, the GDLs were analyzed by scanning electron microscopy, X-ray photoelectron spectroscopy and thermogravimetry. Further, the chemical compositions of H 2 SO 4 solutions before and after immersion test were analyzed with infrared spectroscopy. Results showed that the hydrophobicity of immersed GDL decreased distinctly, which was caused by the damage of physical structure and surface characteristics. Moreover, the immersed GDL showed a worse fuel cell performance than the pristine GDL, especially under a low humidity condition

  5. Encapsulated proppants

    Energy Technology Data Exchange (ETDEWEB)

    Aines, Roger D.; Bourcier, William L.; Duoss, Eric B.; Roberts, Jeffery James; Spadaccini, Christopher M.; Stolaroff, Joshuah K.

    2018-01-30

    A capsule for carrying a proppant for emplaced in a formation containing formation fluid by a hydraulic fracture operation using a fracturing fluid. The capsule includes a capsule body. The capsule body includes a proppant. There is a surface layer on the capsule body that is permeable to the formation fluid or the fracturing fluid or is permeable to both the formation fluid and the fracturing fluid. The proppant material is dry cement that interacts with the formation fluid or the fracturing fluid or both the formation fluid and the fracturing fluid that migrate through the surface layer and is taken up by the dry cement causing the dry cement to harden.

  6. Encapsulated proppants

    Energy Technology Data Exchange (ETDEWEB)

    Aines, Roger D.; Bourcier, William L.; Duoss, Eric B.; Roberts, Jeffery James; Spadaccini, Christopher M.; Stolaroff, Joshuah K.

    2018-01-09

    A capsule for carrying a proppant for emplaced in a formation containing formation fluid by a hydraulic fracture operation using a fracturing fluid. The capsule includes a capsule body. The capsule body includes a proppant. There is a surface layer on the capsule body that is permeable to the formation fluid or the fracturing fluid or is permeable to both the formation fluid and the fracturing fluid. The proppant material is dry cement that interacts with the formation fluid or the fracturing fluid or both the formation fluid and the fracturing fluid that migrate through the surface layer and is taken up by the dry cement causing the dry cement to harden.

  7. Potential Carbon Transport: Linking Soil Aggregate Stability and Sediment Enrichment for Updating the Soil Active Layer within Intensely Managed Landscapes

    Science.gov (United States)

    Wacha, K.; Papanicolaou, T.; Abban, B. K.; Wilson, C. G.

    2014-12-01

    Currently, many biogeochemical models lack the mechanistic capacity to accurately simulate soil organic carbon (SOC) dynamics, especially within intensely managed landscapes (IMLs) such as those found in the U.S. Midwest. These modeling limitations originate by not accounting for downslope connectivity of flowpathways initiated and governed by landscape processes and hydrologic forcing, which induce dynamic updates to the soil active layer (generally top 20-30cm of soil) with various sediment size fractions and aggregates being transported and deposited along the downslope. These hydro-geomorphic processes, often amplified in IMLs by tillage events and seasonal canopy, can greatly impact biogeochemical cycles (e.g., enhanced mineralization during aggregate breakdown) and in turn, have huge implications/uncertainty when determining SOC budgets. In this study, some of these limitations were addressed through a new concept, Potential Carbon Transport (PCT), a term which quantifies a maximum amount of material available for transport at various positions of the landscape, which was used to further refine a coupled modeling framework focused on SOC redistribution through downslope/lateral connectivity. Specifically, the size fractions slaked from large and small aggregates during raindrop-induced aggregate stability tests were used in conjunction with rainfall-simulated sediment enrichment ratio (ER) experiments to quantify the PCT under various management practices, soil types and landscape positions. Field samples used in determining aggregate stability and the ER experiments were collected/performed within the historic Clear Creek Watershed, home of the IML Critical Zone Observatory, located in Southeastern Iowa.

  8. Update on cellular encapsulation.

    Science.gov (United States)

    Smith, Kate E; Johnson, Robert C; Papas, Klearchos K

    2018-05-06

    There is currently a significant disparity between the number of patients who need lifesaving transplants and the number of donated human organs. Xenotransplantation is a way to address this disparity and attempts to enable the use of xenogeneic tissues have persisted for centuries. While immunologic incompatibilities have presented a persistent impediment to their use, encapsulation may represent a way forward for the use of cell-based xenogeneic therapeutics without the need for immunosuppression. In conjunction with modern innovations such as the use of bioprinting, incorporation of immune modulating molecules into capsule membranes, and genetic engineering, the application of xenogeneic cells to treat disorders ranging from pain to liver failure is becoming increasingly realistic. The present review discusses encapsulation in the context of xenotransplantation, focusing on the current status of clinical trials, persistent issues such as antigen shedding, oxygen availability, and donor selection, and recent developments that may address these limitations. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  9. Vascular Displacement in Idiopathic Macular Hole after Single-layered Inverted Internal Limiting Membrane Flap Surgery.

    Science.gov (United States)

    Lee, Jae Jung; Lee, In Ho; Park, Keun Heung; Pak, Kang Yeun; Park, Sung Who; Byon, Ik Soo; Lee, Ji Eun

    2017-08-01

    To compare vascular displacement in the macula after surgical closure of idiopathic macular hole (MH) after single-layered inverted internal limiting membrane (ILM) flap technique and conventional ILM removal. This retrospective study included patients who underwent either vitrectomy and ILM removal only or vitrectomy with single-layered inverted ILM flap for idiopathic MH larger than 400 μm from 2012 to 2015. A customized program compared the positions of the retinal vessels in the macula between preoperative and postoperative photographs. En face images of 6 × 6 mm optical coherence tomography volume scans were registered to calculate the scale. Retinal vessel displacement was measured as a vector value by comparing its location in 16 sectors of a grid partitioned into eight sectors in two rings (inner, 2 to 4 mm; outer, 4 to 6 mm). The distance and angle of displacement were calculated as an average vector and were compared between the two groups for whole sectors, inner ring, outer ring, and for each sector. Twenty patients were included in the ILM flap group and 22 in the ILM removal group. There were no statistical differences between the groups for baseline characteristics. The average displacement in the ILM flap group and the ILM removal group was 56.6 μm at -3.4° and 64.9 μm at -2.7°, respectively, for the whole sectors (p = 0.900), 76.1 μm at -1.1° and 87.3 μm at -0.9° for the inner ring (p = 0.980), and 37.4 μm at -8.2° and 42.7 μm at -6.3° for the outer ring (p = 0.314). There was no statistical difference in the displacement of each of the sectors. Postoperative topographic changes showed no significant differences between the ILM flap and the ILM removal group for idiopathic MH. The single-layered ILM flap technique did not appear to cause additional displacement of the retinal vessels in the macula. © 2017 The Korean Ophthalmological Society

  10. Characterization of anisotropic UF-membranes: top layer thickness and pore structure

    NARCIS (Netherlands)

    Cuperus, F.P.; Cuperus, F.P.; Bargeman, D.; Bargeman, D.; Smolders, C.A.; Smolders, C.A.

    1991-01-01

    Anisotropic poly(2,6-dimethyl-, 1,4-phenylene oxide) (PPO) ultrafiltration membranes are characterized by means of two techniques. A new method for the determination of skin thicknesses, the gold sol method, is introduced and applied to these membranes. The membranes appeared to have a well-defined

  11. Ultrasmall SnO2 Nanocrystals: Hot-bubbling Synthesis, Encapsulation in Carbon Layers and Applications in High Capacity Li-Ion Storage

    Science.gov (United States)

    Ding, Liping; He, Shulian; Miao, Shiding; Jorgensen, Matthew R.; Leubner, Susanne; Yan, Chenglin; Hickey, Stephen G.; Eychmüller, Alexander; Xu, Jinzhang; Schmidt, Oliver G.

    2014-04-01

    Ultrasmall SnO2 nanocrystals as anode materials for lithium-ion batteries (LIBs) have been synthesized by bubbling an oxidizing gas into hot surfactant solutions containing Sn-oleate complexes. Annealing of the particles in N2 carbonifies the densely packed surface capping ligands resulting in carbon encapsulated SnO2 nanoparticles (SnO2/C). Carbon encapsulation can effectively buffer the volume changes during the lithiation/delithiation process. The assembled SnO2/C thus deliver extraordinarily high reversible capacity of 908 mA.h.g-1 at 0.5 C as well as excellent cycling performance in the LIBs. This method demonstrates the great potential of SnO2/C nanoparticles for the design of high power LIBs.

  12. Ultrasmall SnO2 Nanocrystals: Hot-bubbling Synthesis, Encapsulation in Carbon Layers and Applications in High Capacity Li-Ion Storage

    Science.gov (United States)

    Ding, Liping; He, Shulian; Miao, Shiding; Jorgensen, Matthew R.; Leubner, Susanne; Yan, Chenglin; Hickey, Stephen G.; Eychmüller, Alexander; Xu, Jinzhang; Schmidt, Oliver G.

    2014-01-01

    Ultrasmall SnO2 nanocrystals as anode materials for lithium-ion batteries (LIBs) have been synthesized by bubbling an oxidizing gas into hot surfactant solutions containing Sn-oleate complexes. Annealing of the particles in N2 carbonifies the densely packed surface capping ligands resulting in carbon encapsulated SnO2 nanoparticles (SnO2/C). Carbon encapsulation can effectively buffer the volume changes during the lithiation/delithiation process. The assembled SnO2/C thus deliver extraordinarily high reversible capacity of 908 mA·h·g−1 at 0.5 C as well as excellent cycling performance in the LIBs. This method demonstrates the great potential of SnO2/C nanoparticles for the design of high power LIBs. PMID:24732294

  13. Ultrasmall SnO₂ nanocrystals: hot-bubbling synthesis, encapsulation in carbon layers and applications in high capacity Li-ion storage.

    Science.gov (United States)

    Ding, Liping; He, Shulian; Miao, Shiding; Jorgensen, Matthew R; Leubner, Susanne; Yan, Chenglin; Hickey, Stephen G; Eychmüller, Alexander; Xu, Jinzhang; Schmidt, Oliver G

    2014-04-15

    Ultrasmall SnO2 nanocrystals as anode materials for lithium-ion batteries (LIBs) have been synthesized by bubbling an oxidizing gas into hot surfactant solutions containing Sn-oleate complexes. Annealing of the particles in N2 carbonifies the densely packed surface capping ligands resulting in carbon encapsulated SnO2 nanoparticles (SnO2/C). Carbon encapsulation can effectively buffer the volume changes during the lithiation/delithiation process. The assembled SnO2/C thus deliver extraordinarily high reversible capacity of 908 mA·h·g(-1) at 0.5 C as well as excellent cycling performance in the LIBs. This method demonstrates the great potential of SnO2/C nanoparticles for the design of high power LIBs.

  14. Huygens' Principle: The capture of seismic energy by a soft soil layer

    Science.gov (United States)

    Lomnitz, Cinna; Meas, Yunny

    2004-07-01

    Possible nonlinear coupling in surface waves is described at the Texcoco Array (TXC) in Mexico City. Shear-coupled surface waves may be caused by interaction between Rayleigh modes in the basement and resonant shear modes in the uppermost mud layer. Large-amplitude, monochromatic wave trains of long duration appear to be modulated by the fundamental mode of the mud layer. Particle motion features frequent reversals from prograde to retrograde ground motion. Earthquake damage in Mexico City might be related to unrecognized effects related to nonlinear coupling in soft-soil conditions.

  15. Integrating seawater desalination and wastewater reclamation forward osmosis process using thin-film composite mixed matrix membrane with functionalized carbon nanotube blended polyethersulfone support layer.

    Science.gov (United States)

    Choi, Hyeon-Gyu; Son, Moon; Choi, Heechul

    2017-10-01

    Thin-film composite mixed matrix membrane (TFC MMM) with functionalized carbon nanotube (fCNT) blended in polyethersulfone (PES) support layer was synthesized via interfacial polymerization and phase inversion. This membrane was firstly tested in lab-scale integrating seawater desalination and wastewater reclamation forward osmosis (FO) process. Water flux of TFC MMM was increased by 72% compared to that of TFC membrane due to enhanced hydrophilicity. Although TFC MMM showed lower water flux than TFC commercial membrane, enhanced reverse salt flux selectivity (RSFS) of TFC MMM was observed compared to TFC membrane (15% higher) and TFC commercial membrane (4% higher), representing membrane permselectivity. Under effluent organic matter (EfOM) fouling test, 16% less normalized flux decline of TFC MMM was observed compared to TFC membrane. There was 8% less decline of TFC MMM compared to TFC commercial membrane due to fCNT effect on repulsive foulant-membrane interaction enhancement, caused by negatively charged membrane surface. After 10 min physical cleaning, TFC MMM displayed higher recovered normalized flux than TFC membrane (6%) and TFC commercial membrane (4%); this was also supported by visualized characterization of fouling layer. This study presents application of TFC MMM to integrated seawater desalination and wastewater reclamation FO process for the first time. It can be concluded that EfOM fouling of TFC MMM was suppressed due to repulsive foulant-membrane interaction. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Development of computer code for determining prediction parameters of radionuclide migration in soil layer

    International Nuclear Information System (INIS)

    Ogawa, Hiromichi; Ohnuki, Toshihiko

    1986-07-01

    A computer code (MIGSTEM-FIT) has been developed to determine the prediction parameters, retardation factor, water flow velocity, dispersion coefficient, etc., of radionuclide migration in soil layer from the concentration distribution of radionuclide in soil layer or in effluent. In this code, the solution of the predicting equation for radionuclide migration is compared with the concentration distribution measured, and the most adequate values of parameter can be determined by the flexible tolerance method. The validity of finite differential method, which was one of the method to solve the predicting equation, was confirmed by comparison with the analytical solution, and also the validity of fitting method was confirmed by the fitting of the concentration distribution calculated from known parameters. From the examination about the error, it was found that the error of the parameter obtained by using this code was smaller than that of the concentration distribution measured. (author)

  17. Seismic response of nuclear reactors in layered liquefiable soil deposits including nonlinear soil-structure interaction

    International Nuclear Information System (INIS)

    Zaman, M.; Mamoon, S.M.

    1989-01-01

    Analysis of seismic response of structures located at a site with potential for soil liquefaction has drawn attention of many researchers. The topic is particularly important in the design of critical facilities like nuclear reactors and defense installations. This paper presents the results of a study involving evaluation of coupled seismic response of structures (model nuclear reactors) and characteristics of soil liquefaction at a site. The analysis procedure employed is based on the nonlinear finite element (FE) technique and accounts for the interaction effects due to a neighboring structure. Emphasis is given to the following features: prediction of spatial and temporal variation of pore water pressure; identification of the on-set of liquefaction based on the effective stress approach, and tracing the propagation of the liquefied zones with time and resulting response of the structures

  18. Infinite elements for soil-structure interaction analysis in multi-layered halfspaces

    International Nuclear Information System (INIS)

    Yun, Chung Bang; Kim, Jae Min; Yang, Shin Chu

    1994-01-01

    This paper presents the theoretical aspects of a computer code (KIESSI) for soil-structure interaction analysis in a multi-layered halfspace using infinite elements. The shape functions of the infinite elements are derived from approximate expressions of the analytical solutions. Three different infinite elements are developed. They are the horizontal, the vertical and the comer infinite elements (HIE, VIE and CIE). Numerical example analyses are presented for demonstrating the effectiveness of the proposed infinite elements

  19. Mathematical modelling of water and gas transport in layered soil covers for coal ash deposits

    Energy Technology Data Exchange (ETDEWEB)

    Rasmussen, A; Lindgren, M [Kemakta Consultants Co, Stockholm (SE)

    1990-12-17

    In the present work the dry deposition alternative is investigated. In particular the design of soil covers is treated theoretically using mathematical models. The soil cover should primarily act as a barrier against infiltrating water. This is done by having soil cover materials with low permeabilities and sloping covers thereby diverting the infiltrating water in the lateral direction. An important design aspect is that overflow should be avoided since this may cause erosional problems. Thus the design of the cover should allow for lateral water flow within the cover. In the present work we use the computer code TRUST for calculating the flow rates and the moisture contents in two layer covers (till on top of clay) for varying conditions. The calculations so far show that the hydraulic conductivity of the clay layer should be smaller than 10{sup -8} m/s. However, for the simulated longer covers (50 m) a lower hydraulic conductivity gives overflow indicating that better lateral drainage must be provided for. This can be done by increasing the thickness or hydraulic conductivity of the till layer. Simulations for different slopes give little impact, while the hydraulic conductivity of the clay layer is of major importance. Gas transport through the soil cover may be of importance if the waste contains pyrite. In the presence of oxygen and water, pyrite is oxidized producing sulphuric acid. The lowered pH will accelerate the leaching of several heavy metals. The transport rate of gas through a porous material is very sensitive to the water content, decreasing rapidly with increasing water content. In the present work a model, where the unsaturated conditions are accounted for, is outlined. A previously developed method for calculating oxygen transport and oxidation rate of pyrite in connection with mine wastes is generalized from 1D to 2D. A sample calculation illustrates the feasibility of the method. (au) (43 refs.).

  20. Multilayer composite membranes for gas separation based on crosslinked PTMSP gutter layer and partially crosslinked Matrimid R 5218 selective layer

    Czech Academy of Sciences Publication Activity Database

    Peter, Jakub; Peinemann, K.; V.

    2009-01-01

    Roč. 340, 1-2 (2009), s. 62-72 ISSN 0376-7388 Grant - others:Marie Curie fellowship(XE) HPMT-CT-2001-00220 Institutional research plan: CEZ:AV0Z40500505 Keywords : composite membrane * gas separation * PTMSP * Matrimid Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.203, year: 2009

  1. Electrical evaluation of crack generation in SiN{sub x} and SiO{sub x}N{sub y} thin-film encapsulation layers for OLED displays

    Energy Technology Data Exchange (ETDEWEB)

    Park, Eun Kil [Department of Materials Science and Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of); Display Research Center, Samsung Display Co., Ltd., Yongin-City, Gyeonggi-Do 446-711 (Korea, Republic of); Kim, Sungmin [Department of Materials Science and Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of); Heo, Jaeyeong, E-mail: jheo@jnu.ac.kr [Department of Materials Science and Engineering, and the Optoelectronics Convergence Research Center, Chonnam National University, Gwangju 500-757 (Korea, Republic of); Kim, Hyeong Joon, E-mail: thinfilm@snu.ac.kr [Department of Materials Science and Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of)

    2016-05-01

    Highlights: • Crack generation in encapsulation layers were detected by leakage current. • Atomic concentration of SiO{sub x}N{sub y} films affected the bending reliability. • The shapes of the crack tips were affected by the stoichiometry of the SiO{sub x}N{sub y} films. - Abstract: By measuring leakage current density, we detected crack generation in silicon nitride (SiN{sub x}) and silicon oxynitride (SiO{sub x}N{sub y}) thin-film encapsulation layers, and correlated with the films’ water vapor permeability characteristics. After repeated bending cycles, both the changes in water vapor transmission rate and leakage current density were directly proportional to the crack density. Thick SiN{sub x} films had better water vapor barrier characteristics in their pristine state, but cyclic loading led to fast failure. Varying the atomic concentration of the SiO{sub x}N{sub y} films affected their bending reliability. We attribute these differences to changes in the shape of the crack tip as the oxygen content varies.

  2. The importance of defining the geometry of foundations of soil layers for dynamic analysis of Colosseum

    International Nuclear Information System (INIS)

    Beste, H-J.; Clemente, P.; Conti, C.; D'Ovidio, G.; Nakamura, Y.; Orlando, L.; Rea, R.; Rovelli, A.; Valente, G.

    2015-01-01

    By the comparison between tests and analyses, the dynamic characterization was performed, in order to obtain the map of elastic modules for soil Colosseum interaction. The accuracy for foundations and soil is lower than for monument, due ti unknown exact geometry underground. For foundations, a high variability was found of elasticity modules, which was referred to variable damage of concrete for cracking in time. For soil layers, different definitions exist, and we are interested in the best. The vibrations produced by trains are depending on the underground geometry too. The analyses are performed with traditional convoys running on Metro B and C, for the vibrations knowledge on RA XLVII and on ground felt by pedestrians.

  3. RUSLE2015: Modelling soil erosion at continental scale using high resolution input layers

    Science.gov (United States)

    Panagos, Panos; Borrelli, Pasquale; Meusburger, Katrin; Poesen, Jean; Ballabio, Cristiano; Lugato, Emanuele; Montanarella, Luca; Alewell, Christine

    2016-04-01

    Soil erosion by water is one of the most widespread forms of soil degradation in the Europe. On the occasion of the 2015 celebration of the International Year of Soils, the European Commission's Joint Research Centre (JRC) published the RUSLE2015, a modified modelling approach for assessing soil erosion in Europe by using the best available input data layers. The objective of the recent assessment performed with RUSLE2015 was to improve our knowledge and understanding of soil erosion by water across the European Union and to accentuate the differences and similarities between different regions and countries beyond national borders and nationally adapted models. RUSLE2015 has maximized the use of available homogeneous, updated, pan-European datasets (LUCAS topsoil, LUCAS survey, GAEC, Eurostat crops, Eurostat Management Practices, REDES, DEM 25m, CORINE, European Soil Database) and have used the best suited approach at European scale for modelling soil erosion. The collaboration of JRC with many scientists around Europe and numerous prominent European universities and institutes resulted in an improved assessment of individual risk factors (rainfall erosivity, soil erodibility, cover-management, topography and support practices) and a final harmonized European soil erosion map at high resolution. The mean soil loss rate in the European Union's erosion-prone lands (agricultural, forests and semi-natural areas) was found to be 2.46 t ha-1 yr-1, resulting in a total soil loss of 970 Mt annually; equal to an area the size of Berlin (assuming a removal of 1 meter). According to the RUSLE2015 model approximately 12.7% of arable lands in the European Union is estimated to suffer from moderate to high erosion(>5 t ha-1 yr-1). This equates to an area of 140,373 km2 which equals to the surface area of Greece (Environmental Science & Policy, 54, 438-447; 2015). Even the mean erosion rate outstrips the mean formation rate (walls and contouring) through the common agricultural

  4. Thin film Encapsulations of Flexible Organic Light Emitting Diodes

    Directory of Open Access Journals (Sweden)

    Tsai Fa-Ta

    2016-01-01

    Full Text Available Various encapsulated films for flexible organic light emitting diodes (OLEDs were studied in this work, where gas barrier layers including inorganic Al2O3 thin films prepared by atomic layer deposition, organic Parylene C thin films prepared by chemical vapor deposition, and their combination were considered. The transmittance and water vapor transmission rate of the various organic and inorgabic encapsulated films were tested. The effects of the encapsulated films on the luminance and current density of the OLEDs were discussed, and the life time experiments of the OLEDs with these encapsulated films were also conducted. The results showed that the transmittance are acceptable even the PET substrate were coated two Al2O3 and Parylene C layers. The results also indicated the WVTR of the PET substrate improved by coating the barrier layers. In the encapsulation performance, it indicates the OLED with Al2O3 /PET, 1 pair/PET, and 2 pairs/PET presents similarly higher luminance than the other two cases. Although the 1 pair/PET encapsulation behaves a litter better luminance than the 2 pairs/PET encapsulation, the 2 pairs/PET encapsulation has much better life time. The OLED with 2 pairs/PET encapsulation behaves near double life time to the 1 pair encapsulation, and four times to none encapsulation.

  5. ATR FT-IR spectroscopy on Vmh2 hydrophobin self-assembled layers for Teflon membrane bio-functionalization

    International Nuclear Information System (INIS)

    Portaccio, M.; Gravagnuolo, A.M.; Longobardi, S.; Giardina, P.; Rea, I.; De Stefano, L.; Cammarota, M.; Lepore, M.

    2015-01-01

    Graphical abstract: - Highlights: • Hydrophobin self-assembled layers on Teflon in different preparation conditions were investigated. • ATR collection data geometry allowed samples examination without any particular preparation. • Amide content, lipid/amide and carbohydrate/amide ratios of the protein layer were estimated. • Secondary structure of protein was determined for the examined samples. • FT-IR demonstrated to be of extreme relevance in monitoring hydrophobin self-assembled layers preparation. - Abstract: Surface functionalization by layers of hydrophobins, amphiphilic proteins produced by fungi offers a promising and green strategy for fabrication of biomedical and bioanalytical devices. The layering process of the Vmh2 hydrophobin from Pleurotus ostreatus on Teflon membrane has been investigated by Attenuated Total Reflection Fourier Transform Infrared (ATR FT-IR) spectroscopy. In particular, protein layers obtained with hydrophobin purified with two different procedures and in various coating conditions have been examined. The layers have been characterized by quantifying the amide I and amide II band area together with the lipid/amide ratio and carbohydrate/amide ratio. This characterization can be very useful in evaluating the best purification strategy and coating conditions. Moreover the analysis of the secondary structure of the layered protein using the deconvolution procedure of amide I band indicate the prevalent contribution from β-sheet state. The results inferred by infrared spectroscopy have been also confirmed by scanning electron microscopy imaging

  6. ATR FT-IR spectroscopy on Vmh2 hydrophobin self-assembled layers for Teflon membrane bio-functionalization

    Energy Technology Data Exchange (ETDEWEB)

    Portaccio, M., E-mail: marianna.portaccio@unina2.it [Dipartimento di Medicina Sperimentale – Seconda Università di Napoli, Via S.M. di Costantinopoli, 16-80134 Napoli (Italy); Gravagnuolo, A.M., E-mail: alfredomaria.gravagnuolo@unina.it [Dipartimento di Scienze Chimiche, Università “Federico II”, Via Cintia, 21- 80126 Napoli (Italy); Longobardi, S., E-mail: sara.longobardi@unina.it [Dipartimento di Scienze Chimiche, Università “Federico II”, Via Cintia, 21- 80126 Napoli (Italy); Giardina, P., E-mail: paola.giardina@unina.it [Dipartimento di Scienze Chimiche, Università “Federico II”, Via Cintia, 21- 80126 Napoli (Italy); Rea, I., E-mail: ilaria.rea@na.imm.cnr.it [Institute for Microelectronics and Microsystems, CNR, Via P. Castellino, 111-80131 Napoli (Italy); De Stefano, L., E-mail: luca.destefano@na.imm.cnr.it [Institute for Microelectronics and Microsystems, CNR, Via P. Castellino, 111-80131 Napoli (Italy); Cammarota, M., E-mail: marcella.cammarota@unina2.it [Dipartimento di Medicina Sperimentale – Seconda Università di Napoli, Via S.M. di Costantinopoli, 16-80134 Napoli (Italy); Lepore, M., E-mail: maria.lepore@unina2.it [Dipartimento di Medicina Sperimentale – Seconda Università di Napoli, Via S.M. di Costantinopoli, 16-80134 Napoli (Italy)

    2015-10-01

    Graphical abstract: - Highlights: • Hydrophobin self-assembled layers on Teflon in different preparation conditions were investigated. • ATR collection data geometry allowed samples examination without any particular preparation. • Amide content, lipid/amide and carbohydrate/amide ratios of the protein layer were estimated. • Secondary structure of protein was determined for the examined samples. • FT-IR demonstrated to be of extreme relevance in monitoring hydrophobin self-assembled layers preparation. - Abstract: Surface functionalization by layers of hydrophobins, amphiphilic proteins produced by fungi offers a promising and green strategy for fabrication of biomedical and bioanalytical devices. The layering process of the Vmh2 hydrophobin from Pleurotus ostreatus on Teflon membrane has been investigated by Attenuated Total Reflection Fourier Transform Infrared (ATR FT-IR) spectroscopy. In particular, protein layers obtained with hydrophobin purified with two different procedures and in various coating conditions have been examined. The layers have been characterized by quantifying the amide I and amide II band area together with the lipid/amide ratio and carbohydrate/amide ratio. This characterization can be very useful in evaluating the best purification strategy and coating conditions. Moreover the analysis of the secondary structure of the layered protein using the deconvolution procedure of amide I band indicate the prevalent contribution from β-sheet state. The results inferred by infrared spectroscopy have been also confirmed by scanning electron microscopy imaging.

  7. Synthesis of Pt-immobilized on silica and polystyrene-encapsulated silica and their applications as electrocatalysts in the proton exchange membrane fuel cell

    International Nuclear Information System (INIS)

    Yi, Sung-Chul; Kim, Chang Young; Jung, Chi Young; Jeong, Sung Hoon; Kim, Wha Jung

    2011-01-01

    Nano sized Pt particles were successfully immobilized onto SiO 2 and polystyrene-encapsulated silica core shell (SiO 2 @PS). To make the immobilization of Pt onto both silica and polystyrene-encapsulated silica core shell, SiO 2 was first functionalized with -NH 2 using 3-amino propyl trimethoxysilane (APTMS) while for core shell, the negatively charged surface of polystyrene (PS) was changed with positive charge by cationic surfactant such as cetyltrimethylammonium chloride (CTACl) to make the formation of SiO 2 shell on preformed PS sphere. Transmission electron micrograph (TEM) images shows that Pt nanoparticles immobilized onto SiO 2 and SiO 2 @PS were to be 3-4 nm without agglomeraiton. The energy dispersive spectroscope (EDS) shows that Pt contents on both SiO 2 and SiO 2 @PS were to be 21.45% and 20.28%, respectively. In case of Pt-SiO 2 @PS, it is believed that Pt should have been immobilized onto PS surface and pore within SiO 2 shell as well as SiO 2 surface. The MEA fabricated with Pt-SiO 2 @PS shows better cell performance than of Pt-SiO 2 .

  8. Comparative Study of MIL-96(Al) as Continuous Metal-Organic Frameworks Layer and Mixed-Matrix Membrane.

    Science.gov (United States)

    Knebel, Alexander; Friebe, Sebastian; Bigall, Nadja Carola; Benzaqui, Marvin; Serre, Christian; Caro, Jürgen

    2016-03-23

    MIL-96(Al) layers were prepared as supported metal-organic frameworks membrane via reactive seeding using the α-alumina support as the Al source for the formation of the MIL-96(Al) seeds. Depending on the solvent mixture employed during seed formation, two different crystal morphologies, with different orientation of the transport-active channels, have been formed. This crystal orientation and habit is predefined by the seed crystals and is kept in the subsequent growth of the seeds to continuous layers. In the gas separation of an equimolar H2/CO2 mixture, the hydrogen permeability of the two supported MIL-96(Al) layers was found to be highly dependent on the crystal morphology and the accompanied channel orientation in the layer. In addition to the neat supported MIL-96(Al) membrane layers, mixed-matrix membranes (MMMs, 10 wt % filler loading) as a composite of MIL-96(Al) particles as filler in a continuous Matrimid polymer phase have been prepared. Five particle sizes of MIL-96(Al) between 3.2 μm and 55 nm were synthesized. In the preparation of the MIL-96(Al)/Matrimid MMM (10 wt % filler loading), the following preparation problems have been identified: The bigger micrometer-sized MIL-96(Al) crystals show a trend toward sedimentation during casting of the MMM, whereas for nanoparticles aggregation and recrystallization to micrometer-sized MIL-96(Al) crystals has been observed. Because of these preparation problems for MMM, the neat supported MIL-96(Al) layers show a relatively high H2/CO2 selectivity (≈9) and a hydrogen permeance approximately 2 magnitudes higher than that of the best MMM.

  9. Encapsulation of curcumin in polyelectrolyte nanocapsules and their neuroprotective activity

    Science.gov (United States)

    Szczepanowicz, Krzysztof; Jantas, Danuta; Piotrowski, Marek; Staroń, Jakub; Leśkiewicz, Monika; Regulska, Magdalena; Lasoń, Władysław; Warszyński, Piotr

    2016-09-01

    Poor water solubility and low bioavailability of lipophilic drugs can be potentially improved with the use of delivery systems. In this study, encapsulation of nanoemulsion droplets was utilized to prepare curcumin nanocarriers. Nanosize droplets containing the drug were encapsulated in polyelectrolyte shells formed by the layer-by-layer (LbL) adsorption of biocompatible polyelectrolytes: poly-L-lysine (PLL) and poly-L-glutamic acid (PGA). The size of synthesized nanocapsules was around 100 nm. Their biocompatibility and neuroprotective effects were evaluated on the SH-SY5Y human neuroblastoma cell line using cell viability/toxicity assays (MTT reduction, LDH release). Statistically significant toxic effect was clearly observed for PLL coated nanocapsules (reduction in cell viability about 20%-60%), while nanocapsules with PLL/PGA coating did not evoke any detrimental effects on SH-SY5Y cells. Curcumin encapsulated in PLL/PGA showed similar neuroprotective activity against hydrogen peroxide (H2O2)-induced cell damage, as did 5 μM curcumin pre-dissolved in DMSO (about 16% of protection). Determination of concentration of curcumin in cell lysate confirmed that curcumin in nanocapsules has cell protective effect in lower concentrations (at least 20 times) than when given alone. Intracellular mechanisms of encapsulated curcumin-mediated protection engaged the prevention of the H2O2-induced decrease in mitochondrial membrane potential (MMP) but did not attenuate Reactive Oxygen Species (ROS) formation. The obtained results indicate the utility of PLL/PGA shell nanocapsules as a promising, alternative way of curcumin delivery for neuroprotective purposes with improved efficiency and reduced toxicity.

  10. TDR water content inverse profiling in layered soils during infiltration and evaporation

    Science.gov (United States)

    Greco, R.; Guida, A.

    2009-04-01

    During the last three decades, time domain reflectometry (TDR) has become one of the most commonly used tools for soil water content measurements either in laboratory or in the field. Indeed, TDR provides easy and cheap water content estimations with relatively small disturbance to the investigated soil. TDR measurements of soil water content are based on the strong correlation between relative dielectric permittivity of wet soil and its volumetric water content. Several expressions of the relationship between relative dielectric permittivity and volumetric water content have been proposed, empirically stated (Topp et al., 1980) as well as based on semi-analytical approach to dielectric mixing models (Roth et al., 1990; Whalley, 1993). So far, TDR field applications suffered the limitation due to the capability of the technique of estimating only the mean water content in the volume investigated by the probe. Whereas the knowledge of non homogeneous vertical water content profiles was needed, it was necessary to install either several vertical probes of different length or several horizontal probes placed in the soil at different depths, in both cases strongly increasing soil disturbance as well as the complexity of the measurements. Several studies have been recently dedicated to the development of inversion methods aimed to extract more information from TDR waveforms, in order to estimate non homogeneous moisture profiles along the axis of the metallic probe used for TDR measurements. A common feature of all these methods is that electromagnetic transient through the wet soil along the probe is mathematically modelled, assuming that the unknown soil water content distribution corresponds to the best agreement between simulated and measured waveforms. In some cases the soil is modelled as a series of small layers with different dielectric properties, and the waveform is obtained as the result of the superposition of multiple reflections arising from impedance

  11. Preparation of dual-layer coated polyester membranes with nuclear tracks and their wave-absorbing property

    International Nuclear Information System (INIS)

    Liu Cunxiong; Hu Lian; Ni Bangfa; Tian Weizhi; Fan Qiwen; Xiao Caijin; Nie Peng; Wang Pingsheng; Zhang Guiying; Huang Donghui

    2010-01-01

    Nanometer materials are of importance in developing electromagnetic-wave-absorbing materials. In this work, 16 μm thick polyester membranes were bombarded by 140 MeV 32 S ions from the HI-13 tandem accelerator to produce latent tracks. The bombarded samples were sensitized by DMF and UV light at 360 nm wavelength, before chemical etching by NaOH solution to develop latent tracks into pores in sizes of nanometers or micrometers in full depth of the membrane. The samples were coated with thin layers of barium ferrite and magnesium fluoride by vacuum evaporation. The reflectivity indices were measured at 2-18 GHz. The results indicate that the modified polyester membrane can effectively absorb 8-18 GHz radar waves.(authors)

  12. Biological activity of soddy-calcareous soils and cultural layers in Alanian settlements of the Kislovodsk basin

    Science.gov (United States)

    Chernysheva, E. V.; Kashirskaya, N. N.; Korobov, D. S.; Borisov, A. V.

    2014-09-01

    Microbiological investigations of cultural layers were performed in a settlement of the Alanian culture—Podkumskoe-2 (the 2nd-4th centuries AD). The present-day soddy-calcareous soils (rendzinas) used for different purposes were also studied near this settlement. The most significant changes in the initial characteristics of the soil microbial communities occurred under the residential influence more than 1500 years ago; these changes have been preserved until the present time. In the areas subjected to the anthropogenic impact, the total microbial biomass (the weighted average of 3720 μg C/g soil) was lower than that in the background soil. The minimal values of the microbial biomass were found in the soil of the pasture—2.5 times less than in the background soil. The urease activity of the cultural layer was higher than that of the soils nearby the settlement. Elevated values of the cellulose activity were also recorded only in the cultural layers. The current plowing has led to a significant decrease in the mycelium biomass of the microscopic fungi. In the soil of the fallow, the weighted average value of the fungal hyphae biomass along the profile was twice lower than that in the background soil and cultural layers of the settlement. The pasture first affected the active microbial biomass and, to a lesser extent, the amount of microscopic fungi.

  13. Microstructural properties of non-supported microporous ceramic membrane top-layers obtained by the sol-gel process

    NARCIS (Netherlands)

    de Lange, Rob; de Lange, R.S.A.; Hekkink, J.H.A.; Hekkink, J.H.A.; Keizer, Klaas; Burggraaf, Anthonie; Burggraaf, A.J.

    1996-01-01

    Dried and calcined non-supported membrane top-layers of SiO2, SiO2/TiO2, SiO2/ZrO2 (10, 20 and 30 mol% TiO2 and ZrO2, respectively) and SiO2/Al2O3 (10 mol% AlO1.5) were prepared using acid catalyzed hydrolysis and condensation of alkoxides in ethanol. The microstructure was determined using nitrogen

  14. A novel catalyst layer structure based surface-patterned Nafion® membrane for high-performance direct methanol fuel cell

    DEFF Research Database (Denmark)

    Chen, Ming; Wang, Meng; Ding, Xianan

    2018-01-01

    .5% respectively, compared with the conventional catalyst layer. Performance improvement is attributed to the fact that the novel catalyst layer structure optimizes the electrolyte membrane/catalyst layer and gas diffusion layer/catalyst layer interfacial structure, which increases the electrochemical reaction......Conventional catalyst layer with a smooth surface exists the larger area of“catalytic dead zone” and reduces the utilization of catalyst. Based on this, a novel catalyst layer structure based surface-patterned Nafion® membrane was designed to achieve more efficient electrochemical reaction...... to prepare the novel catalyst layer, and the effect of pressure on the performance of MEA was investigated. The results suggested that the peak power density of DMFC with optimal novel catalyst layer structure increased by 28.84%, the charge transfer resistances of anode and cathode reduced by 28.8% and 26...

  15. Preparation and evaluation of tamsulosin hydrochloride sustained-release pellets modified by two-layered membrane techniques

    Directory of Open Access Journals (Sweden)

    Jingmin Wang

    2015-02-01

    Full Text Available The aim of the present study was to develop tamsulosin hydrochloride sustained-release pellets using two-layered membrane techniques. Centrifugal granulator and fluidized-bed coater were employed to prepare drug-loaded pellets and to employ two-layered membrane coating respectively. The prepared pellets were evaluated for physicochemical characterization, subjected to differential scanning calorimetry (DSC and in vitro release of different pH. Different release models and scanning electron microscopy (SEM were utilized to analyze the release mechanism of Harnual® and home-made pellets. By comparing the dissolution profiles, the ratio and coating weight gain of Eudragit® NE30D and Eudragit® L30D55 which constitute the inside membrane were identified as 18:1 and 10%–11%. The coating amount of outside membrane containing Eudragit® L30D55 was determined to be 0.8%. The similarity factors (f2 of home-made capsule and commercially available product (Harnual® were above 50 in different dissolution media. DSC studies confirmed that drug and excipients had good compatibility and SEM photographs showed the similarities and differences of coating surface between Harnual® and self-made pellets before and after dissolution. According to Ritger-Peppas model, the two dosage form had different release mechanism.

  16. Microbial Community and Functional Structure Significantly Varied among Distinct Types of Paddy Soils But Responded Differently along Gradients of Soil Depth Layers

    Directory of Open Access Journals (Sweden)

    Ren Bai

    2017-05-01

    Full Text Available Paddy rice fields occupy broad agricultural area in China and cover diverse soil types. Microbial community in paddy soils is of great interest since many microorganisms are involved in soil functional processes. In the present study, Illumina Mi-Seq sequencing and functional gene array (GeoChip 4.2 techniques were combined to investigate soil microbial communities and functional gene patterns across the three soil types including an Inceptisol (Binhai, an Oxisol (Leizhou, and an Ultisol (Taoyuan along four profile depths (up to 70 cm in depth in mesocosm incubation columns. Detrended correspondence analysis revealed that distinctly differentiation in microbial community existed among soil types and profile depths, while the manifest variance in functional structure was only observed among soil types and two rice growth stages, but not across profile depths. Along the profile depth within each soil type, Acidobacteria, Chloroflexi, and Firmicutes increased whereas Cyanobacteria, β-proteobacteria, and Verrucomicrobia declined, suggesting their specific ecophysiological properties. Compared to bacterial community, the archaeal community showed a more contrasting pattern with the predominant groups within phyla Euryarchaeota, Thaumarchaeota, and Crenarchaeota largely varying among soil types and depths. Phylogenetic molecular ecological network (pMEN analysis further indicated that the pattern of bacterial and archaeal communities interactions changed with soil depth and the highest modularity of microbial community occurred in top soils, implying a relatively higher system resistance to environmental change compared to communities in deeper soil layers. Meanwhile, microbial communities had higher connectivity in deeper soils in comparison with upper soils, suggesting less microbial interaction in surface soils. Structure equation models were developed and the models indicated that pH was the most representative characteristics of soil type and

  17. Microbial Community and Functional Structure Significantly Varied among Distinct Types of Paddy Soils But Responded Differently along Gradients of Soil Depth Layers.

    Science.gov (United States)

    Bai, Ren; Wang, Jun-Tao; Deng, Ye; He, Ji-Zheng; Feng, Kai; Zhang, Li-Mei

    2017-01-01

    Paddy rice fields occupy broad agricultural area in China and cover diverse soil types. Microbial community in paddy soils is of great interest since many microorganisms are involved in soil functional processes. In the present study, Illumina Mi-Seq sequencing and functional gene array (GeoChip 4.2) techniques were combined to investigate soil microbial communities and functional gene patterns across the three soil types including an Inceptisol (Binhai), an Oxisol (Leizhou), and an Ultisol (Taoyuan) along four profile depths (up to 70 cm in depth) in mesocosm incubation columns. Detrended correspondence analysis revealed that distinctly differentiation in microbial community existed among soil types and profile depths, while the manifest variance in functional structure was only observed among soil types and two rice growth stages, but not across profile depths. Along the profile depth within each soil type, Acidobacteria , Chloroflexi , and Firmicutes increased whereas Cyanobacteria , β -proteobacteria , and Verrucomicrobia declined, suggesting their specific ecophysiological properties. Compared to bacterial community, the archaeal community showed a more contrasting pattern with the predominant groups within phyla Euryarchaeota , Thaumarchaeota , and Crenarchaeota largely varying among soil types and depths. Phylogenetic molecular ecological network (pMEN) analysis further indicated that the pattern of bacterial and archaeal communities interactions changed with soil depth and the highest modularity of microbial community occurred in top soils, implying a relatively higher system resistance to environmental change compared to communities in deeper soil layers. Meanwhile, microbial communities had higher connectivity in deeper soils in comparison with upper soils, suggesting less microbial interaction in surface soils. Structure equation models were developed and the models indicated that pH was the most representative characteristics of soil type and

  18. A multi-layer box model of carbon dynamics in soil

    International Nuclear Information System (INIS)

    Kuc, T.

    2005-01-01

    A multi-layer box model (MLB) for quantification of carbon fluxes between soil and atmosphere has been developed. In the model, soil carbon reservoir is represented by two boxes: fast decomposition box (FDB) and slow decomposition box (SDB), characterised by substantially different turnover time (TT) of carbon compounds. Each box has an internal structure (sub-compartments) accounting for carbon deposited in consecutive time intervals. The rate of decomposition of carbon compounds in each sub-compartment is proportional to the carbon content. With the aid of the MLB model and the 14 C signature of carbon dioxide, the fluxes entering and leaving the boxes, turnover time of carbon in each box, and the ratio of mass of carbon in the slow and fast box (M s /M f ) were calculated. The MBL model yields the turnover time of carbon in the FDB (TT f ) ca. 14 for typical investigated soils of temperate climate ecosystems. The calculated contribution of the CO 2 flux originating from the slow box (F s ) to the total CO 2 flux into the atmosphere ranges from 12% to 22%. These values are in agreement with experimental observations at different locations. Assuming that the input flux of carbon (F i n) to the soil system is doubled within the period of 100 years, the soil buffering capacity for excess carbon predicted by the MLB model for typical soil parameters may vary in the range between 26% and 52%. The highest values are obtained for soils characterised by long TTf, and well developed old carbon pool. (author)

  19. Enhanced biogeochemical cycling and subsequent reduction of hydraulic conductivity associated with soil-layer interfaces in the vadose zone

    Science.gov (United States)

    Hansen, David J.; McGuire, Jennifer T.; Mohanty, Binayak P.

    2013-01-01

    Biogeochemical dynamics in the vadose zone are poorly understood due to the transient nature of chemical and hydrologic conditions, but are nonetheless critical to understanding chemical fate and transport. This study explored the effects of a soil layer on linked geochemical, hydrological, and microbiological processes. Three laboratory soil columns were constructed: a homogenized medium-grained sand, a homogenized organic-rich loam, and a sand-over-loam layered column. Upward and downward infiltration of water was evaluated during experiments to simulate rising water table and rainfall events respectively. In-situ collocated probes measured soil water content, matric potential, and Eh while water samples collected from the same locations were analyzed for Br−, Cl−, NO3−, SO42−, NH4+, Fe2+, and total sulfide. Compared to homogenous columns, the presence of a soil layer altered the biogeochemistry and water flow of the system considerably. Enhanced biogeochemical cycling was observed in the layered column over the texturally homogeneous soil columns. Enumerations of iron and sulfate reducing bacteria showed 1-2 orders of magnitude greater community numbers in the layered column. Mineral and soil aggregate composites were most abundant near the soil-layer interface; the presence of which, likely contributed to an observed order-of-magnitude decrease in hydraulic conductivity. These findings show that quantifying coupled hydrologic-biogeochemical processes occurring at small-scale soil interfaces is critical to accurately describing and predicting chemical changes at the larger system scale. Findings also provide justification for considering soil layering in contaminant fate and transport models because of its potential to increase biodegradation and/or slow the rate of transport of contaminants. PMID:22031578

  20. Temperature and moisture effects on greenhouse gas emissions from deep active-layer boreal soils

    Science.gov (United States)

    Bond-Lamberty, Ben; Smith, A. Peyton; Bailey, Vanessa

    2016-12-01

    Rapid climatic changes, rising air temperatures, and increased fires are expected to drive permafrost degradation and alter soil carbon (C) cycling in many high-latitude ecosystems. How these soils will respond to changes in their temperature, moisture, and overlying vegetation is uncertain but critical to understand given the large soil C stocks in these regions. We used a laboratory experiment to examine how temperature and moisture control CO2 and CH4 emissions from mineral soils sampled from the bottom of the annual active layer, i.e., directly above permafrost, in an Alaskan boreal forest. Gas emissions from 30 cores, subjected to two temperatures and either field moisture conditions or experimental drought, were tracked over a 100-day incubation; we also measured a variety of physical and chemical characteristics of the cores. Gravimetric water content was 0.31 ± 0.12 (unitless) at the beginning of the incubation; cores at field moisture were unchanged at the end, but drought cores had declined to 0.06 ± 0.04. Daily CO2 fluxes were positively correlated with incubation chamber temperature, core water content, and percent soil nitrogen. They also had a temperature sensitivity (Q10) of 1.3 and 1.9 for the field moisture and drought treatments, respectively. Daily CH4 emissions were most strongly correlated with percent nitrogen, but neither temperature nor water content was a significant first-order predictor of CH4 fluxes. The cumulative production of C from CO2 was over 6 orders of magnitude higher than that from CH4; cumulative CO2 was correlated with incubation temperature and moisture treatment, with drought cores producing 52-73 % lower C. Cumulative CH4 production was unaffected by any treatment. These results suggest that deep active-layer soils may be sensitive to changes in soil moisture under aerobic conditions, a critical factor as discontinuous permafrost thaws in interior Alaska. Deep but unfrozen high-latitude soils have been shown to be

  1. Soil hydraulic material properties and layered architecture from time-lapse GPR

    Science.gov (United States)

    Jaumann, Stefan; Roth, Kurt

    2018-04-01

    Quantitative knowledge of the subsurface material distribution and its effective soil hydraulic material properties is essential to predict soil water movement. Ground-penetrating radar (GPR) is a noninvasive and nondestructive geophysical measurement method that is suitable to monitor hydraulic processes. Previous studies showed that the GPR signal from a fluctuating groundwater table is sensitive to the soil water characteristic and the hydraulic conductivity function. In this work, we show that the GPR signal originating from both the subsurface architecture and the fluctuating groundwater table is suitable to estimate the position of layers within the subsurface architecture together with the associated effective soil hydraulic material properties with inversion methods. To that end, we parameterize the subsurface architecture, solve the Richards equation, convert the resulting water content to relative permittivity with the complex refractive index model (CRIM), and solve Maxwell's equations numerically. In order to analyze the GPR signal, we implemented a new heuristic algorithm that detects relevant signals in the radargram (events) and extracts the corresponding signal travel time and amplitude. This algorithm is applied to simulated as well as measured radargrams and the detected events are associated automatically. Using events instead of the full wave regularizes the inversion focussing on the relevant measurement signal. For optimization, we use a global-local approach with preconditioning. Starting from an ensemble of initial parameter sets drawn with a Latin hypercube algorithm, we sequentially couple a simulated annealing algorithm with a Levenberg-Marquardt algorithm. The method is applied to synthetic as well as measured data from the ASSESS test site. We show that the method yields reasonable estimates for the position of the layers as well as for the soil hydraulic material properties by comparing the results to references derived from ground

  2. Encapsulated scintillation detector

    International Nuclear Information System (INIS)

    Toepke, I.L.

    1982-01-01

    A scintillation detector crystal is encapsulated in a hermetically sealed housing having a glass window. The window may be mounted in a ring by a compression seal formed during cooling of the ring and window after heating. The window may be chemically bonded to the ring with or without a compression seal. The ring is welded to the housing along thin weld flanges to reduce the amount of weld heat which must be applied. A thin section is provided to resist the flow of welding heat to the seal between the ring and the window thereby forming a thermal barrier. The thin section may be provided by a groove cut partially through the wall of the ring. A layer of PTFE between the tubular body and the crystal minimizes friction created by thermal expansion. Spring washers urge the crystal towards the window. (author)

  3. Chemical and physical passivation of type II strained-layer superlattice devices by means of thiolated self-assembled monolayers and polymer encapsulates

    Science.gov (United States)

    Henry, Nathan C.; Knorr, Daniel B.; Williams, Kristen S.; Baril, Neil; Nallon, Eric; Lenhart, Joseph L.; Andzelm, Jan W.; Pellegrino, Joseph; Tidrow, Meimei; Cleveland, Erin; Bandara, Sumith

    2015-05-01

    The efficacy of solution deposition of thiolated self-assembled monolayers (SAMs) has been explored for the purpose of passivating III-V type II superlattice (T2SL) photodetectors, more specifically a p-type heterojunction device. Sulfur passivation has previously been achieved on T2SL devices. However, degradation over time, temperature sensitivity and inconsistent reproducibility necessitate a physical encapsulate that can chemically bond to the chemical passivant. Thus, this research investigates two passivation methods, surface passivation with a thiol monolayer and passivation with a polymer encapsulant with a view toward future combination of these techniques. Analysis of the physical and chemical condition of the surface prior to deposition assisted in the development of ideal processes for optimized film quality. Successful deposition was facilitated by in situ oxide removal. Various commercially available functional (cysteamine) and non-functional (alkane) thiolated monolayers were investigated. Dark current was reduced by 3 orders of magnitude and achieved negligible surface leakage at low bias levels. The lowest dark current result, 7.69 × 10-6 A/cm2 at 50 mV, was achieved through passivation with cysteamine.

  4. Numerical combination for nonlinear analysis of structures coupled to layered soils

    Directory of Open Access Journals (Sweden)

    Wagner Queiroz Silva

    Full Text Available This paper presents an alternative coupling strategy between the Boundary Element Method (BEM and the Finite Element Method (FEM in order to create a computational code for the analysis of geometrical nonlinear 2D frames coupled to layered soils. The soil is modeled via BEM, considering multiple inclusions and internal load lines, through an alternative formulation to eliminate traction variables on subregions interfaces. A total Lagrangean formulation based on positions is adopted for the consideration of the geometric nonlinear behavior of frame structures with exact kinematics. The numerical coupling is performed by an algebraic strategy that extracts and condenses the equivalent soil's stiffness matrix and contact forces to be introduced into the frame structures hessian matrix and internal force vector, respectively. The formulation covers the analysis of shallow foundation structures and piles in any direction. Furthermore, the piles can pass through different layers. Numerical examples are shown in order to illustrate and confirm the accuracy and applicability of the proposed technique.

  5. Capping hazardous red mud using acidic soil with an embedded layer of zeolite for plant growth.

    Science.gov (United States)

    Ma, Yingqun; Si, Chunhua; Lin, Chuxia

    2014-01-01

    A nearly three-year microcosm experiment was conducted to test the effectiveness of capping red mud using acidic soil with an embedded layer of zeolite in sustaining the growth of a grass species. This 'sandwich-structured' design allowed self-sustaining growth of the plants under rain-fed conditions no matter whether the underlying red mud was neutralized or not. During the initial stage, the plants grew better when the red mud was not neutralized with MgCl2 probably due to pH rise in the root zone. Neutralization of red mud led to salinization and pH decrease in the root zone. However, the difference in plant growth performance between these scenarios became less remarkable over time due to gradual improvement of soil conditions in the neutralized scenarios. Continuous leaching of soluble salts and alkali by rainwater extended the root zone to the red mud layer. As a result of vegetative production, soil organic matter rapidly accumulated. This, combined with increase in pH and decrease in salinity, markedly facilitated microbial activities and consequently improved the supply of nutrients. This study provides abasis for field-scale experimental design that will have implications for effectively establishing vegetative cover in red mud disposal sites to control dust hazards.

  6. Development of migration prediction system (MIGSTEM) for cationic species of radionuclides through soil layers

    International Nuclear Information System (INIS)

    Ohnuki, Toshihiko; Takebe, Shinichi; Yamamoto, Tadatoshi

    1989-01-01

    The migration prediction system (MIGSTEM) has been developed for estimating the migration of cationic species of radionuclides through soil layers systematically. The MIGSTEM consists of the migration experiments, the one-dimensional fitting code (inverse analysis code) for determining retardation factor and dispersivity (migration factors) and the three-dimensional differential code (prediction code) for estimating the migration of the radionuclides. The migration experiments are carried out for obtaining the concentration profiles of the radionuclides in unsaturated and saturated soil layers. Using the inverse analysis code, the migration factors are obtained at one time by fitting the concentration profiles calculated to those observed. The prediction code can give the contours of concentration and the one-dimensional concentration profiles at selected time, as well as the changing in the concentration at a selected position with time. The validity of the MIGSTEM was obtained by the benchmark test on the prediction and inverse analysis codes. The MIGSTEM was applied to estimate the migration of Sr 2+ through the sandy soil. (author)

  7. Effects of alterations of the E. coli lipopolysaccharide layer on membrane permeabilization events induced by Cecropin A.

    Science.gov (United States)

    Agrawal, Anurag; Weisshaar, James C

    2018-04-22

    The outermost layer of Gram negative bacteria is composed of a lipopolysaccharide (LPS) network that forms a dense protective hydrophilic barrier against entry of hydrophobic drugs. At low μM concentrations, a large family of cationic polypeptides known as antimicrobial peptides (AMPs) are able to penetrate the LPS layer and permeabilize the outer membrane (OM) and the cytoplasmic membrane (CM), causing cell death. Cecropin A is a well-studied cationic AMP from moth. Here a battery of time-resolved, single-cell microscopy experiments explores how deletion of sugar layers and/or phosphoryl negative charges from the core oligosaccharide layer (core OS) of K12 E. coli alters the timing of OM and CM permeabilization induced by Cecropin A. Deletion of sugar layers, or phosphoryl charges, or both from the core OS shortens the time to the onset of OM permeabilization to periplasmic GFP and also the lag time between OM permeabilization and CM permeabilization. Meanwhile, the 12-h minimum inhibitory concentration (MIC) changes only twofold with core OS alterations. The results suggest a two-step model in which the core oligosaccharide layers act as a kinetic barrier to penetration of Cecropin A to the lipid A outer leaflet of the OM. Once a threshold concentration has built up at the lipid A leaflet, nucleation occurs and the OM is locally permeabilized to GFP and, by inference, to Cecropin A. Whenever Cecropin A permeabilizes the OM, CM permeabilization always follows, and cell growth subsequently halts and never recovers on the 45 min observation timescale. Copyright © 2018 Elsevier B.V. All rights reserved.

  8. A novel reverse osmosis membrane by ferrous sulfate assisted controlled oxidation of polyamide layer

    Science.gov (United States)

    Raval, Hiren D.; Raviya, Mayur R.; Gauswami, Maulik V.

    2017-11-01

    With growing desalination capacity, it is very important to evaluate the performance of thin film composite reverse osmosis (TFC RO) membrane in terms of energy consumption for desalination. There is a trade-off between salt rejection and water-flux of TFC RO membrane. This article presents a novel approach of analyzing the effect of mixture of an oxidizing agent sodium hypochlorite and a reducing agent ferrous sulfate on virgin TFC RO membrane. Experiments were carried out by varying the concentrations of both sodium hypochlorite and ferrous sulfate. The negative charge was induced on the membrane due to the treatment of combination of sodium hypochlorite and ferrous sulfate, thereby resulting in higher rejection of negative ions due to repulsive force. Membrane treated with 1000 mg l-1 sodium hypochlorite and 2000 mg l-1 ferrous sulfate showed the best salt rejection i.e. 96.23%. The characterization was carried out to understand the charge on the membrane surface by Zeta potential, morphology of membrane surface by scanning electron microscope (SEM), surface roughness features by atomic force microscope (AFM) and chemical structural changes by nuclear magnetic resonance (NMR) analysis.

  9. Encapsulation of radioactive waste

    International Nuclear Information System (INIS)

    Pordes, O.; Plows, J.P.

    1980-01-01

    A method is described for encapsulating a particular radioactive waste which consists of suspending the waste in a viscous liquid encapsulating material, of synthetic resin monomers or prepolymers, and setting the encapsulating material by addition or condensation polymerization to form a solid material in which the waste is dispersed. (author)

  10. Soil Surface Organic Layers in Alaska's Arctic Foothills: Development, Distribution and Microclimatic Feedbacks

    Science.gov (United States)

    Baughman, C. A.; Mann, D. H.; Verbyla, D.; Valentine, D.; Kunz, M. L.; Heiser, P. A.

    2013-12-01

    Accumulated organic matter at the ground surface plays an important role in arctic ecosystems. These soil surface organic layers (SSOLs) influence temperature, moisture, and chemistry in the underlying mineral soil and, on a global basis, comprise enormous stores of labile carbon. Understanding the dynamics of SSOLs is prerequisite to modeling the responses of arctic ecosystem processes to climate changes. Here, we ask three questions regarding SSOLs in the Arctic Foothills in northern Alaska: 1) What environmental factors control their spatial distribution? 2) How long do they take to form? 3) What is the relationship between SSOL thickness and mineral soil temperature through the growing season? The best topographically-controlled predictors of SSOL thickness and spatial distribution are duration of sunlight during the growing-season, upslope drainage area, slope gradient, and elevation. SSOLs begin to form within several decades following disturbance but require 500-700 years to reach equilibrium states. Once formed, mature SSOLs lower peak growing-season temperature and mean annual temperature in the underlying mineral horizon by 8° and 3° C respectively, which reduces available growing degree days within the upper mineral soil by nearly 80%. How ongoing climate change in northern Alaska will affect the region's SSOLs is an open and potentially crucial question.

  11. Top layer enhances biological ontrol of thrips in ornamentals :"Predatory mites survive better on rich soil cover

    NARCIS (Netherlands)

    Hoogstraten, van K.; Grosman, A.H.

    2014-01-01

    An organic top layer over the soil or substrate can enhance the biological control of thrips in roses and alstroemerias. The top layer contains food for prey mites, which in turn serve as food for predatory mites. In this way the predators survive longer. Thus, as the thrips population increases, an

  12. Dynamics of the Fouling Layer Microbial Community in a Membrane Bioreactor

    DEFF Research Database (Denmark)

    Ziegler, Anja Sloth; McIlroy, Simon Jon; Larsen, Poul

    2016-01-01

    Membrane fouling presents the greatest challenge to the application of membrane bioreactor (MBR) technology. Formation of biofilms on the membrane surface is the suggested cause, yet little is known of the composition or dynamics of the microbial community responsible. To gain an insight...... of the fouling process, we concurrently investigated the communities of the biofilm, MBR bulk sludge, and the conventional activated sludge system used to seed the MBR system over several weeks from start-up. As the biofilm matured the initially abundant betaproteobacterial genera Limnohabitans, Hydrogenophaga...

  13. Synthesis of hyperbranched copolyimides and their application as selective layers in composite membranes

    Czech Academy of Sciences Publication Activity Database

    Peter, Jakub; Kosmala, Barbara; Bleha, Miroslav

    2009-01-01

    Roč. 245, 1-3 (2009), s. 516-526 ISSN 0011-9164. [Engineering with Membranes 2008; Membrane Processes: Development, Monitoring and Modelling – From the Nano to the Macro Scale – EWM 2008. Vale do Lobo, Algarve, 25.05.2008-28.05.2008] R&D Projects: GA MPO 2A-1TP1/116 Institutional research plan: CEZ:AV0Z40500505 Keywords : hyperbranched polyimide * composite membrane * gas separation * soluble polyimide Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.034, year: 2009

  14. Two Outer Membrane Proteins Contribute to Caulobacter crescentus Cellular Fitness by Preventing Intracellular S-Layer Protein Accumulation

    Energy Technology Data Exchange (ETDEWEB)

    Overton, K. Wesley; Park, Dan M.; Yung, Mimi C.; Dohnalkova, Alice; Smit, John; Jiao, Yongqin

    2016-09-23

    ABSTRACT

    Surface layers, or S-layers, are two-dimensional protein arrays that form the outermost layer of many bacteria and archaea. They serve several functions, including physical protection of the cell from environmental threats. The high abundance of S-layer proteins necessitates a highly efficient export mechanism to transport the S-layer protein from the cytoplasm to the cell exterior.Caulobacter crescentusis unique in that it has two homologous, seemingly redundant outer membrane proteins, RsaFaand RsaFb, which together with other components form a type I protein translocation pathway for S-layer export. These proteins have homology toEscherichia coliTolC, the outer membrane channel of multidrug efflux pumps. Here we provide evidence that, unlike TolC, RsaFaand RsaFbare not involved in either the maintenance of membrane stability or the active export of antimicrobial compounds. Rather, RsaFaand RsaFbare required to prevent intracellular accumulation and aggregation of the S-layer protein RsaA; deletion of RsaFaand RsaFbled to a general growth defect and lowered cellular fitness. Using Western blotting, transmission electron microscopy, and transcriptome sequencing (RNA-seq), we show that loss of both RsaFaand RsaFbled to accumulation of insoluble RsaA in the cytoplasm, which in turn caused upregulation of a number of genes involved in protein misfolding and degradation pathways. These findings provide new insight into the requirement for RsaFaand RsaFbin cellular fitness and tolerance to antimicrobial agents and further our understanding of the S-layer export mechanism on both the transcriptional and translational levels in

  15. Unexpectedly high soil organic carbon stocks under impervious surfaces contributed by urban deep cultural layers

    Science.gov (United States)

    Bae, J.; Ryu, Y.

    2017-12-01

    The expansion of urban artificial structures has altered the spatial distribution of soil organic carbon (SOC) stocks. The majority of the urban soil studies within the land-cover types, however, focused on top soils despite the potential of deep soils to store large amounts of SOC. Here, we investigate vertical distribution of SOC stocks in both impervious surfaces (n = 11) and adjacent green spaces (n = 8) to a depth of 4 m with in an apartment complex area, Seoul, Republic of Korea. We found that more than six times differences in SOC stocks were observed at 0-1 m depth between the impervious surfaces (1.90 kgC m-2) and the green spaces (12.03 kgC m-2), but no significant differences appeared when comparing them at the depth of 0-4 m. We found "cultural layers" with the largest SOC stocks at 1-2 m depth in the impervious surfaces (15.85 kgC m-2) and 2-3 m depths in urban green spaces (12.52 kgC m-2). Thus, the proportions of SOC stocks at the 0-1 m depth to the total of 0-4 m depth were 6.83% in impervious surfaces and 32.15% in urban green spaces, respectively. The 13C and 15N stable isotope data with historical aerial photographs revealed that the cropland which existed before 1978 formed the SOC in the cultural layers. Our results highlight that impervious surface could hold large amount of SOC stock which has been overlooked in urban carbon cycles. We believe this finding will help city planners and policy makers to develop carbon management programs better towards sustainable urban ecosystems.

  16. Irreversible membrane fouling abatement through pre-deposited layer of hierarchical porous carbons

    KAUST Repository

    Hamad, Juma; Dua, Rubal; Kurniasari, Novita; Kennedy, Maria Dolores; Wang, Peng; Amy, Gary L.

    2014-01-01

    In this work, dual-templated hierarchical porous carbons (HPCs), produced from a coupled ice-hard templating approach, are shown to be a highly effective solution to the commonly occurring problem of irreversible fouling of low-pressure membranes

  17. Effect of PVP Intermediate Layer on the Properties of SAPO 34 Membrane

    Directory of Open Access Journals (Sweden)

    Jugal K. Das

    2012-01-01

    Full Text Available SAPO 34 zeolite membranes were prepared on a tubular mullite support. Before membrane preparation, the support surfaces were coated with seed crystals. Seeds particles were prepared by hydrothermal synthesis. Before seeding, the substrates were treated with polyvinylpyrrolidone (PVP to orient the seeds. Both the treated and untreated supports were seeded, and membranes were synthesized on those support tubes by ex situ hydrothermal method. The PVP molecule exists in the two resonance structures. Hence the acylamino bond –N+ = C–O-– acts as intermediate linker between support surface and seed surface. Due to charge interaction, the seed crystals were anchored strongly to support surface. The synthesized membranes along with seed crystals were characterized by XRD, FESEM, and EDAX analysis. The single-gas permeation with CO2 and H2 was investigated. Up to 5 bar of feed pressure, the permselectivity of CO2 and H2 was as high as 4.2.

  18. Mathematical modelling of water and gas transport in layered soil covers for coal ash deposit

    Energy Technology Data Exchange (ETDEWEB)

    Lindgren, M [Kemakta Consultants Co, Stockholm (SE); Rasmuson, A [Chalmers University of Technology, Goeteborg (SE). Dept. of Chemical Engineering Design

    1991-06-19

    In phase 1 of this study the design of soil covers for deposits of coal ash from energy production was studied with regard to various parameters like: climate, cover slope, hydraulic conductivity of tight layer and length of cover. One of the main results was the relatively large risk for total saturation up to the surface and overflow which may cause surface erosion problems. In the present study two theoretical cases are studied to further elucidate the problem. A case from the phase 1 study is used to illustrate the effect of increased infiltration. Calculations show that total saturation and thereby overflow is achieved when the infiltration is increased by 20% in March, but not when increased by 10% only. This shows that the margin in an acceptable case may be small. A cover treated in phase 1, where totally saturated conditions were obtained, was modified so that two decimeters of the one meter till in its bottom part were exchanged for a drainage layer. It is shown that the effect of this layer is large. A negative side-effect, however, is that gas flow may increase due to the lower saturation of the cover. Calculations were made for a real soil covered mine tailings deposit at Bersbo. This deposit was chosen mainly because it is the only well documented case in Sweden where soil covers are used for securing a deposit, but also because some contradictory results as compared to theory were obtained. Another topic studied in the present work was the influence of a heterogeneous clay layer. For example, a weak zone with a hydraulic conductivity of 10{sup -7} m/s (10{sup -9} m/s for the rest of the clay), covering 0.5 m x 0.5 m of 10 m in length and 5 m in width, will increase the flow through the bottom of the cover with almost 30%. The gas transport through the heterogeneous soil cover was also studied, showing about 5 times increased gas transport rate around the weak zone, but almost no difference about 1 m from the weak zone. (29 figs., 5 tabs., 27 refs.).

  19. The effect of inclined soil layers on surface vibration from underground railways using a semi-analytical approach

    International Nuclear Information System (INIS)

    Jones, S; Hunt, H

    2009-01-01

    Ground vibration due to underground railways is a significant source of disturbance for people living or working near the subways. The numerical models used to predict vibration levels have inherent uncertainty which must be understood to give confidence in the predictions. A semi-analytical approach is developed herein to investigate the effect of soil layering on the surface vibration of a halfspace where both soil properties and layer inclination angles are varied. The study suggests that both material properties and inclination angle of the layers have significant effect (± 10dB) on the surface vibration response.

  20. Considerations for successful transplantation of encapsulated pancreatic islets

    NARCIS (Netherlands)

    de Vos, P; Hamel, AF; Tatarkiewicz, K

    Encapsulation of pancreatic islets allows for transplantion in the absence of immunosuppression. The technology is based on the principle that transplanted tissue is protected for the host immune system by an artificial membrane. Encapsulation offers a solution to the shortage of donors in clinical

  1. Presence of Fe-Al binary oxide adsorbent cake layer in ceramic membrane filtration and their impact for removal of HA and BSA.

    Science.gov (United States)

    Kim, Kyung-Jo; Jang, Am

    2018-04-01

    To enhance the removal of natural organic matter (NOM) in ceramic (Ce) membrane filtration, an iron-aluminum binary oxide (FAO) was applied to the ceramic membrane surface as the adsorbent cake layer, and it was compared with heated aluminum oxide (HAO) for the evaluation of the control of NOM. Both the HAO and FAO adsorbent cake layers efficiently removed the NOM regardless of NOM's hydrophobic/hydrophilic characteristics, and the dissolved organic carbon (DOC) removal in NOM for FAO was 1-1.12 times greater than that for HAO, which means FAO was more efficient in the removal of DOC in NOM. FAO (0.03 μm), which is smaller in size than HAO (0.4 μm), had greater flux reduction than HAO. The flux reduction increased as the filtration proceeded because most of the organic foulants (colloid/particles and soluble NOM) were captured by the adsorbent cake layer, which caused fouling between the membrane surface and the adsorbent cake layer. However, no chemically irreversible fouling was observed on the Ce membrane at the end of the FAO adsorbent cake layer filtration. This means that a stable adsorbent cake layer by FAO formed on the Ce membrane, and that the reduced pure water flux of the Ce membrane, resulting from the NOM fouling, can easily be recovered through physicochemical cleaning. Copyright © 2018 Elsevier Ltd. All rights reserved.

  2. Tracer methods to quantify nutrient uptake from plough layer, sub-soil and fertilizer: implications on sustainable nutrient management

    Energy Technology Data Exchange (ETDEWEB)

    Haak, E [Swedish Univ. of Agricultural Sciences, Uppsala (Sweden). Dept. of Radioecology

    1996-07-01

    Two soils injection methods are presented. The first method consists of homogeneously labelling the whole plough layer with carrier free tracers. this is done in two treatments, (1) a reference treatment without connection with the sub-soil and (2) an experimental treatment where the sub-soil is freely accessible for root penetration. The second method, which is now under development, consists of using isotope labelled fertilizers instead of carrier free tracers. By application of the A-value concept it is possible to quantify (by the first method) the plant uptake of nutrients from plough layer and sub-soil, and from the second method, the uptake of nutrients from the applied fertilizer. A fertilizer strategy for phosphorus is discussed based on data obtained from tracer experiment in the field, and soil survey of specific field sites. (author). 7 refs, 2 figs, 1 tab.

  3. Tracer methods to quantify nutrient uptake from plough layer, sub-soil and fertilizer: implications on sustainable nutrient management

    International Nuclear Information System (INIS)

    Haak, E.

    1996-01-01

    Two soils injection methods are presented. The first method consists of homogeneously labelling the whole plough layer with carrier free tracers. this is done in two treatments, (1) a reference treatment without connection with the sub-soil and (2) an experimental treatment where the sub-soil is freely accessible for root penetration. The second method, which is now under development, consists of using isotope labelled fertilizers instead of carrier free tracers. By application of the A-value concept it is possible to quantify (by the first method) the plant uptake of nutrients from plough layer and sub-soil, and from the second method, the uptake of nutrients from the applied fertilizer. A fertilizer strategy for phosphorus is discussed based on data obtained from tracer experiment in the field, and soil survey of specific field sites. (author). 7 refs, 2 figs, 1 tab

  4. Novel electrospun gas diffusion layers for polymer electrolyte membrane fuel cells: Part I. Fabrication, morphological characterization, and in situ performance

    Science.gov (United States)

    Chevalier, S.; Lavielle, N.; Hatton, B. D.; Bazylak, A.

    2017-06-01

    In this first of a series of two papers, we report an in-depth analysis of the impact of the gas diffusion layer (GDL) structure on the polymer electrolyte membrane (PEM) fuel cell performance through the use of custom GDLs fabricated in-house. Hydrophobic electrospun nanofibrous gas diffusion layers (eGDLs) are fabricated with controlled fibre diameter and alignment. The eGDLs are rendered hydrophobic through direct surface functionalization, and this molecular grafting is achieved in the absence of structural alteration. The fibre diameter, chemical composition, and electrical conductivity of the eGDL are characterized, and the impact of eGDL structure on fuel cell performance is analysed. We observe that the eGDL facilitates higher fuel cell power densities compared to a commercial GDL (Toray TGP-H-60) at highly humidified operating conditions. The ohmic resistance of the fuel cell is found to significantly increase with increasing inter-fiber distance. It is also observed that the addition of a hydrophobic treatment enhances membrane hydration, and fibres perpendicularly aligned to the channel direction may enhance the contact area between the catalyst layer and the GDL.

  5. Nacre-Templated Synthesis of Highly Dispersible Carbon Nanomeshes for Layered Membranes with High-Flux Filtration and Sensing Properties.

    Science.gov (United States)

    Kong, Meng; Li, Mingjie; Shang, Ruoxu; Wu, Jingyu; Yan, Peisong; Xu, Dongmei; Li, Chaoxu

    2018-01-24

    Marine shells not only represent a rapidly accumulating type of fishery wastes but also offer a unique sort of hybrid nanomaterials produced greenly and massively in nature. The elaborate "brick and mortar" structures of nacre enabled the synthesis of carbon nanomeshes with <1 nm thickness, hierarchical porosity, and high specific surface area through pyrolysis, in which two-dimensional (2D) organic layers served as the carbonaceous precursor and aragonite platelets as the hard template. Mineral bridges within 2D organic layers templated the formation of mesh pores of 20-70 nm. In contrast to other hydrophobic carbon nanomaterials, these carbon nanomeshes showed super dispersibility in diverse solvents and thus processability for membranes through filtration, patterning, spray-coating, and ink-writing. The carbon membranes with layered structures were capable of serving not only for high-flux filtration and continuous flow absorption but also for electrochemical and strain sensing with high sensitivity. Thus, utilization of marine shells, on one hand, relieves the environmental concern of shellfish waste, on the other hand, offers a facile, green, low-cost, and massive approach to synthesize unique carbon nanomeshes alternative to graphene nanomeshes and applicable in environmental adsorption, filtration, wearable sensors, and flexible microelectronics.

  6. Peclet number analysis of cross-flow in porous gas diffusion layer of polymer electrolyte membrane fuel cell (PEMFC).

    Science.gov (United States)

    Suresh, P V; Jayanti, Sreenivas

    2016-10-01

    Adoption of hydrogen economy by means of using hydrogen fuel cells is one possible solution for energy crisis and climate change issues. Polymer electrolyte membrane (PEM) fuel cell, which is an important type of fuel cells, suffers from the problem of water management. Cross-flow is induced in some flow field designs to enhance the water removal. The presence of cross-flow in the serpentine and interdigitated flow fields makes them more effective in proper distribution of the reactants on the reaction layer and evacuation of water from the reaction layer than diffusion-based conventional parallel flow fields. However, too much of cross-flow leads to flow maldistribution in the channels, higher pressure drop, and membrane dehydration. In this study, an attempt has been made to quantify the amount of cross-flow required for effective distribution of reactants and removal of water in the gas diffusion layer. Unit cells containing two adjacent channels with gas diffusion layer (GDL) and catalyst layer at the bottom have been considered for the parallel, interdigitated, and serpentine flow patterns. Computational fluid dynamics-based simulations are carried out to study the reactant transport in under-the-rib area with cross-flow in the GDL. A new criterion based on the Peclet number is presented as a quantitative measure of cross-flow in the GDL. The study shows that a cross-flow Peclet number of the order of 2 is required for effective removal of water from the GDL. Estimates show that this much of cross-flow is not usually produced in the U-bends of Serpentine flow fields, making these areas prone to flooding.

  7. Human T-cell line (Jurkat cell) encapsulation by nano-organized polyelectrolytes and their response assessment in vitro and in vivo

    Energy Technology Data Exchange (ETDEWEB)

    Pandey, Siddharth [Institute of Nuclear Medicine and Allied Sciences (INMAS), Stem Cell and Gene Therapy Research Group (India); Afrin, Fahrat [Jamia Hamdard, Department of Biotechnology (India); Tripathi, R. P.; Gangenahalli, Gurudutta, E-mail: gugdutta@rediffmail.com [Institute of Nuclear Medicine and Allied Sciences (INMAS), Stem Cell and Gene Therapy Research Group (India)

    2013-07-15

    Single living Jurkat cells have been encapsulated through polyelectrolytes nanoparticles poly(allyl amine hydrochloride) size 15.6 nm and poly(styrene-co-sulfonic acid sodium salt) size 30.2 nm, through layer by layer coating of oppositely charged plasma membrane. Confocal microscopy and scanning electron microscopy results showed complete shielding of Jurkat cells, and no changes in cell surface morphology of encapsulated cells were observed. Cell viability was not affected after encapsulation and no toxicity was found. In vivo studies demonstrated no significant changes in hematological and biochemical parameters of blood serum at day 1 and 7 in mice. Histopathological analyses of liver and spleen tissues showed nontoxic nature of prepared formulations.

  8. Spatial variation in soil active-layer geochemistry across hydrologic margins in polar desert ecosystems

    Directory of Open Access Journals (Sweden)

    J. E. Barrett

    2009-12-01

    Full Text Available Polar deserts are characterized by severe spatial-temporal limitations of liquid water. In soil active layers of the Antarctic Dry Valleys, liquid water is infrequently available over most of the arid terrestrial landscape. However, soils on the margins of glacial melt-water streams and lakes are visibly wet during the brief Austral summer when temperatures permit the existence of liquid water. We examined the role of these hydrologic margins as preferential zones for the transformation and transport of nutrient elements and solutes in an environment where geochemical weathering and biological activity is strictly limited by the dearth of liquid water. We report on hydropedological investigations of aquatic-terrestrial transition zones adjacent to 11 stream and lake systems in the Antarctic Dry Valleys. Our results show that wetted zones extended 1–11 m from the edges of lotic and lentic systems. While capillary demand and surface evaporation drive a one-way flux of water through these zones, the scale of these transition zones is determined by the topography and physical characteristics of the surrounding soils. Nutrient concentrations and fluxes appear to be influenced by both the hydrology and microbial-mediated biogeochemical processes. Salt concentrations are enriched near the distal boundary of the wetted fronts due to evapo-concentration of pore water in lake margin soils, while organic matter, ammonium and phosphate concentrations are highest in stream channel sediments where potential for biological activity is greatest. Thus, in the Antarctic Dry Valleys, intermittently wet soils on the margins of streams and lakes are important zones of both geochemical cycling and biological activity.

  9. Predicting bioavailability of PAHs in field-contaminated soils by passive sampling with triolein embedded cellulose acetate membranes

    Energy Technology Data Exchange (ETDEWEB)

    Tao Yuqiang [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085 (China); Zhang Shuzhen [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085 (China)], E-mail: szzhang@rcees.ac.cn; Wang Zijian [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085 (China); Christie, Peter [Queen' s University Belfast, Agricultural and Environmental Science Department, Newforge Lane, Belfast BT9 5PX (United Kingdom)

    2009-02-15

    Triolein embedded cellulose acetate membrane (TECAM) was used for passive sampling of the fraction of naphthalene, phenanthrene, pyrene and benzo[a]pyrene in 18 field-contaminated soils. The sampling process of PAHs by TECAM fitted well with a first-order kinetics model and PAHs reached 95% of equilibrium in TECAM within 20 h. Concentrations of PAHs in TECAM (C{sub TECAM}) correlated well with the concentrations in soils (r{sup 2} = 0.693-0.962, p < 0.001). Furthermore, concentrations of PAHs determined in the soil solution were very close to the values estimated by C{sub TECAM} and the partition coefficient between TECAM and water (K{sub TECAM-w}). After lipid normalization nearly 1:1 relationships were observed between PAH concentrations in TECAMs and earthworms exposed to the soils (r{sup 2} = 0.591-0.824, n = 18, p < 0.01). These results suggest that TECAM can be a useful tool to predict bioavailability of PAHs in field-contaminated soils. - Triolein embedded cellulose acetate membranes can be a useful tool to predict bioavailability of PAHs in field-contaminated soils.

  10. Multilayer emulsions as a strategy for linseed oil and α-lipoic acid micro-encapsulation: study on preparation and in vitro characterization.

    Science.gov (United States)

    Huang, Juan; Wang, Qiang; Li, Tong; Xia, Nan; Xia, Qiang

    2018-01-04

    Linseed oil and α-lipoic acid are bioactive ingredients, which play an important role in human nutrition and health. However, their application in functional foods is limited because of their instabilities and poor solubilities in hydrophilic matrices. Multilayer emulsions are particularly useful to protect encapsulated bioactive ingredients. The aim of this study was to fabricate multilayer emulsions by a high-pressure homogenization method to encapsulate linseed oil and α-lipoic acid simultaneously. Tween 20 and lecithin were used as surfactants to stabilize the oil droplets of primary emulsions. Multilayer emulsions were produced by using an electrostatic layer-by-layer deposition process of lecithin-chitosan membranes. Thermal treatment exhibited that chitosan encapsulation could improve the thermal stability of primary emulsions. During in vitro digestion, it was found that chitosan encapsulation had little effect on the lipolysis of linseed oil and bioaccessibility of α-lipoic acid. The oxidation stability of linseed oil in multilayer emulsions was improved effectively by chitosan encapsulation and α-lipoic acid. Chitosan encapsulation could inhibit the degradation of α-lipoic acid. A physical stability study indicated that multilayer emulsions had good centrifugal, dilution and storage stabilities. Multilayer emulsion is an effective delivery system to incorporate linseed oil and α-lipoic acid into functional foods and beverages. © 2018 Society of Chemical Industry. © 2018 Society of Chemical Industry.

  11. Investigations on the double gas diffusion backing layer for performance improvement of self-humidified proton exchange membrane fuel cells

    International Nuclear Information System (INIS)

    Kong, Im Mo; Jung, Aeri; Kim, Min Soo

    2016-01-01

    Highlights: • The performance of self-humidified PEMFCs can be improved with double GDBL. • The effect of double GDBL on water retention capability and membrane hydration was investigated. • In addition to HFR and EIS measurements, numerical analysis was conducted. • Optimized design of double GDBL for self-humidified PEMFC was investigated. • This study provides an inspiration on how to design the double GDBL. - Abstract: In order to simplify the system configuration and downsize the volume, a proton exchange membrane fuel cell (PEMFC) needs to be operated in a self-humidified mode without any external humidifiers. However, in self-humidified PEMFCs, relatively low cell performance is a problem to be solved. In our previous study, a gas diffusion layer (GDL) containing double gas diffusion backing layer (GDBL) coated by single micro porous layer (MPL) was introduced and its effect on the cell performance was evaluated. In the present study, the effect of the double GDBL was investigated by measuring high frequency resistance (HFR) and electrochemical impedance spectroscopy (EIS). In the experiments, the HFR value was remarkably reduced, while the diameter of semicircle of EIS was increased. It means that the membrane hydration was improved due to enhanced water retention capability of the GDL despite of interrupted gas diffusion. The result of numerical analysis also showed that the water retention capability of GDL can be improved with proper structure design of double GDBL. Based on the result, optimized design of double GDBL for water retention was obtained numerically. The result of this study provides useful information on the structural design of GDBL for self-humidified PEMFCs.

  12. Logisnet: A tool for multimethod, multiple soil layers slope stability analysis

    Science.gov (United States)

    Legorreta Paulin, G.; Bursik, M.

    2009-05-01

    Shallow landslides and slope failures have been studied from several points of view (inventory, heuristic, statistic, and deterministic). In particular, numerous methods embedded in Geographic Information Systems (GIS) applications have been developed to assess slope stability. However, little work has been done on the systematic comparison of different techniques and the incorporation of vertical contrasts of geotechnical properties in multiple soil layers. In this research, stability is modeled by using LOGISNET, an acronym for Multiple Logistic Regression, Geographic Information System, and Neural Network. The main purpose of LOGISNET is to provide government planners and decision makers a tool to assess landslide susceptibility. The system is fully operational for models handling an enhanced cartographic-hydrologic model (SINMAP) and multiple logistic regression. The enhanced implementation of SINMAP was tested at regional scale in the Highway 101 corridor in Del Norte County, California, and its susceptibility map was found to have improved factor of safety estimates based on comparison with landslide inventory maps. The enhanced SINMAP and multiple logistic regression subsystems have functions that allow the user to include vertical variation in geotechnical properties through summation of forces in specific soil layers acting on failure planes for a local or regional-scale mapping. The working group of LOGISNET foresees the development of an integrated tool system to handle and support the prognostic studies of slope instability, and communicate the results to the public through maps.

  13. Spatial variability of detrended soil plow layer penetrometer resistance transect in a sugarcane field

    Science.gov (United States)

    Pérez, Luis D.; Cumbrera, Ramiro; Mato, Juan; Millán, Humberto; Tarquis, Ana M.

    2015-04-01

    Spatial variability of soil properties is relevant for identifying those zones with physical degradation. In this sense, one has to face the problem of identifying the origin and distribution of spatial variability patterns (Brouder et al., 2001; Millán et al., 2012). The objective of the present work was to quantify the spatial structure of soil penetrometer resistance (PR) collected from a transect data consisted of 221 points equidistant. In each sampling, readings were obtained from 0 cm till 70 cm of depth, with an interval of 5 cm (Pérez, 2012). The study was conducted on a Vertisol (Typic Hapludert) dedicated to sugarcane (Saccharum officinarum L.) production during the last sixty years (Pérez et al., 2010). Recently, scaling approach has been applied on the determination of the scaling data properties (Tarquis et al., 2008; Millán et al., 2012; Pérez, 2012). We focus in the Hurst analysis to characterize the data variability for each depth. Previously a detrended analysis was conducted in order to better study de intrinsic variability of the series. The Hurst exponent (H) for each depth was estimated showing a characteristic pattern and differentiating PR evolution in depth. References Brouder, S., Hofmann, B., Reetz, H.F., 2001. Evaluating spatial variability of soil parameters for input management. Better Crops 85, 8-11. Millán, H; AM Tarquís, Luís D. Pérez, Juan Mato, Mario González-Posada, 2012. Spatial variability patterns of some Vertisol properties at a field scale using standardized data. Soil and Tillage Research, 120, 76-84. Pérez, Luís D. 2012. Influencia de la maquinaria agrícola sobre la variabilidad espacial de la compactación del suelo. Aplicación de la metodología geoestadística-fractal. PhD thesis, UPM (In Spanish). Pérez, Luís D., Humberto Millán, Mario González-Posada 2010. Spatial complexity of soil plow layer penetrometer resistance as influenced by sugarcane harvesting: A prefractal approach. Soil and Tillage

  14. In situ observation of the growth of biofouling layer in osmotic membrane bioreactors by multiple fluorescence labeling and confocal laser scanning microscopy.

    Science.gov (United States)

    Yuan, Bo; Wang, Xinhua; Tang, Chuyang; Li, Xiufen; Yu, Guanghui

    2015-05-15

    Since the concept of the osmotic membrane bioreactor (OMBR) was introduced in 2008, it has attracted growing interests for its potential applications in wastewater treatment and reclamation; however, the fouling mechanisms of forward osmosis (FO) membrane especially the development of biofouling layer in the OMBR are not yet clear. Here, the fouled FO membranes were obtained from the OMBRs on days 3, 8 and 25 in sequence, and then the structure and growing rule of the biofouling layer formed on the FO membrane samples were in-situ characterized by multiple fluorescence labeling and confocal laser scanning microscopy (CLSM). CLSM images indicated that the variations in abundance and distribution of polysaccharides, proteins and microorganisms in the biofouling layer during the operation of OMBRs were significantly different. Before the 8th day, their biovolume dramatically increased. Subsequently, the biovolumes of β-d-glucopyranose polysaccharides and proteins continued increasing and leveled off after 8 days, respectively, while the biovolumes of α-d-glucopyranose polysaccharides and microorganisms decreased. Extracellular polymeric substances (EPS) played a significant role in the formation and growth of biofouling layer, while the microorganisms were seldom detected on the upper fouling layer after 3 days. Based on the results obtained in this study, the growth of biofouling layer on the FO membrane surface in the OMBR could be divided into three stages. Initially, EPS was firstly deposited on the FO membrane surface, and then microorganisms associated with EPS located in the initial depositing layer to form clusters. After that, the dramatic increase of the clusters of EPS and microorganisms resulted in the quick growth of biofouling layer during the flux decline of the OMBR. However, when the water flux became stable in the OMBR, some microorganisms and EPS would be detached from the FO membrane surface. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Water-Permeable Dialysis Membranes for Multi-Layered Micro Dialysis System

    Directory of Open Access Journals (Sweden)

    Naoya eTo

    2015-06-01

    Full Text Available This paper presents the development of water-permeable dialysis membranes that are suitable for an implantable microdialysis system that does not use dialysis fluid. We developed a microdialysis system integrating microfluidic channels and nanoporous filtering membranes made of polyethersulfone (PES, aiming at a fully implantable system that drastically improves the quality of life of patients. Simplicity of the total system is crucial for the implantable dialysis system, where the pumps and storage tanks for the dialysis fluid pose problems. Hence, we focus on hemofiltration, which does not require the dialysis fluid but water-permeable membranes. We investigated the water-permeability of the PES membrane with respect to the concentrations of the PES, the additives, and the solvents in the casting solution. Sufficiently water-permeable membranes were found through in vitro experiments using whole bovine blood. The filtrate was verified to have the concentrations of low-molecular-weight molecules, such as sodium, potassium, urea, and creatinine, while proteins, such as albumin, were successfully blocked by the membrane. We conducted in vivo experiments using rats, where the system was connected to the femoral artery and jugular vein. The filtrate was successfully collected without any leakage of blood inside the system and it did not contain albumin but low-molecular-weight molecules whose concentrations were identical to those of the blood. The rat model with renal failure showed 100% increase of creatinine in 5 h, while rats connected to the system showed only a 7.4% increase, which verified the effectiveness of the proposed microdialysis system.

  16. Sensitivity of WRF-simulated planetary boundary layer height to land cover and soil changes

    Directory of Open Access Journals (Sweden)

    Ferenc Ács

    2014-09-01

    Full Text Available Planetary boundary layer (PBL height sensitivity to both so-called single and accumulated land cover and soil changes is investigated in shallow convection under cloud-free conditions to compare the effects. Single land cover type and soil changes are carried out to be able to unequivocally separate the cause and effect relationships. The Yonsei University scheme in the framework of the Weather Research Forecasting (WRF mesoscale modeling system is used as a research tool. The area investigated lies in the Carpathian Basin, where anticyclonic weather type influence dominated on the five summer days chosen for simulations. Observation-based methods applied for validating diurnal PBL height courses manifest great deviations reaching 500–1300 m. The obtained deviations are somewhat smaller around midday and greater at night. They can originate either from the differences in the measuring principles or from the differences in the atmospheric profiles used. Concerning sensitivity analyses, we showed that PBL height differences caused by soil change are comparable with the PBL height differences caused by land cover change. The differences are much greater in the single than in the accumulated tests. Space averaged diurnal course difference around midday reaching a few tens of meters can be presumably treated as strongly significant. PBL height differences obtained in the sensitivity analyses are, at least in our case, smaller than those obtained by applying different observation based methods. The results may be utilized in PBL height diurnal course analyses.

  17. A Layered Past: the Transformation and Development of Legacy Sediments as Alluvial Soils

    Science.gov (United States)

    Wade, A.; Richter, D. D., Jr.

    2017-12-01

    Legacy sediments are a widespread consequence of post-colonial upland erosion in the United States. Although these deposits are ubiquitous in valley bottoms of the southeastern Piedmont, mature hardwood forests and collapsed stream banks mask their occurrence. While these deposits have been studied for their fluvial dynamics and water quality impacts, they have received less attention in regards to soil structure and formation. In this study, we characterized legacy sediment mineraology, composition and structure to understand how pedogenic processes are overprinting sediment layering in a 40-hectare Piedmont floodplain. To constrain the timing of deposition, we used Pb-210 and C-14 dating on buried charcoal and tree stumps. Our results show that in 100 years of forest regeneration, vegetation and oscillating floodplain conditions have driven these eroded sediment deposits to evolve as soil profiles both in structure and composition. These textural and nutrient gradients have ramifications for the subsurface flow of nutrients through the floodplain. Given the estimated millennia it will take to erode legacy sediment from Piedmont floodplains, it is important to think of these deposits as new stable environments on their own trajectory of soil evolution.

  18. Atomic layer deposition of AlN for thin membranes using trimethylaluminum and H2/N2 plasma

    International Nuclear Information System (INIS)

    Goerke, Sebastian; Ziegler, Mario; Ihring, Andreas; Dellith, Jan; Undisz, Andreas; Diegel, Marco; Anders, Solveig; Huebner, Uwe; Rettenmayr, Markus; Meyer, Hans-Georg

    2015-01-01

    Highlights: • AlN films grown at 150 °C by ALD using trimethylaluminum and H 2 /N 2 -plasma. • Nearly stoichiometric AlN films (ratio Al:N = 0.938), polycrystalline by XRD/TEM. • Refractive index of n = 1.908 and low thermal conductivity of κ = 1.66 W/(m K). • Free-standing AlN membranes mechanically stable and buckling free (tensile strain). • Membrane patterning by focused ion beam etching possible. - Abstract: Aluminum nitride (AlN) thin films with thicknesses from 20 to 100 nm were deposited on silicon, amorphous silica, silicon nitride, and vitreous carbon by plasma enhanced atomic layer deposition (PE-ALD). Trimethylaluminum (TMA) and a H 2 /N 2 plasma mixture were used as precursors. We investigated the influence of deposition temperature and plasma parameters on the growth characteristics and the film properties of AlN. Stable PE-ALD growth conditions were obtained from 150 °C to the highest tested temperature of 300 °C. The growth rate, refractive index, and thickness homogeneity on 4″ wafers were determined by spectroscopic ellipsometry. X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM) and Rutherford backscattering spectrometry (RBS) were carried out to analyze crystallinity and composition of the films. Furthermore, the thermal conductivity and the film stress were determined. The stress was sufficiently low to fabricate mechanically stable free-standing AlN membranes with lateral dimensions of up to 2.2 × 2.2 mm 2 . The membranes were patterned with focused ion beam etching. Thus, these AlN membranes qualify as dielectric support material for a variety of potential applications

  19. Mechanisms and modeling development of water transport/phase change in catalyst layers of portion exchange membrane fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Yexiang [Dept. of Thermal Engineering, Tsinghua University Beijing (China)], email: Yexiang.Xiao@energy.lth.se; Yuan, Jinliang; Sunden, Bengt [Dept. of Energy Sciences, Faculty of Engineering, Lund University (Sweden)], email: Jinliang.yuan@energy.lth.se, email: bengt.sunden@energy.lth.se

    2011-07-01

    Research on proton exchange membrane fuel cells has shown that incorporation of nanosized catalysts can effectively increase active areas and catalyst activity and make a great contribution to development in performance and catalyst utilization. Multiphase transport processes are as significant and complicated as water generation/transfer processes which occur in nano-structured catalyst layers. A review project has been launched aimed at gaining a comprehensive understanding of the mechanisms of water generation or transport phenomena. It covers catalytic reactions and water-phase change within the catalyst layers. The review proceeds in three main stages: Firstly, it characterizes and reconstructs the nano/micro-structured pores and solid-phases; secondly, it emphasises the importance of sensitive and consistent analysis of various water-phase change and transport schemes; and thirdly, it recommends development of microscopic models for multi-phase transport processes in the pores and the solid phases.

  20. Sclerosing Encapsulating Peritonitis; Review

    Directory of Open Access Journals (Sweden)

    Norman O. Machado

    2016-05-01

    Full Text Available Sclerosing encapsulating peritonitis (SEP is a rare chronic inflammatory condition of the peritoneum with an unknown aetiology. Also known as abdominal cocoon, the condition occurs when loops of the bowel are encased within the peritoneal cavity by a membrane, leading to intestinal obstruction. Due to its rarity and nonspecific clinical features, it is often misdiagnosed. The condition presents with recurrent episodes of small bowel obstruction and can be idiopathic or secondary; the latter is associated with predisposing factors such as peritoneal dialysis or abdominal tuberculosis. In the early stages, patients can be managed conservatively; however, surgical intervention is necessary for those with advanced stage intestinal obstruction. A literature review revealed 118 cases of SEP; the mean age of these patients was 39 years and 68.0% were male. The predominant presentation was abdominal pain (72.0%, distension (44.9% or a mass (30.5%. Almost all of the patients underwent surgical excision (99.2% without postoperative complications (88.1%.

  1. Gravity-driven membrane filtration as pretreatment for seawater reverse osmosis: linking biofouling layer morphology with flux stabilization.

    Science.gov (United States)

    Akhondi, Ebrahim; Wu, Bing; Sun, Shuyang; Marxer, Brigit; Lim, Weikang; Gu, Jun; Liu, Linbo; Burkhardt, Michael; McDougald, Diane; Pronk, Wouter; Fane, Anthony G

    2015-03-01

    In this study gravity-driven membrane (GDM) ultrafiltration is investigated for the pretreatment of seawater before reverse osmosis (RO). The impacts of temperature (21 ± 1 and 29 ± 1 °C) and hydrostatic pressure (40 and 100 mbar) on dynamic flux development and biofouling layer structure were studied. The data suggested pore constriction fouling was predominant at the early stage of filtration, during which the hydrostatic pressure and temperature had negligible effects on permeate flux. With extended filtration time, cake layer fouling played a major role, during which higher hydrostatic pressure and temperature improved permeate flux. The permeate flux stabilized in a range of 3.6 L/m(2) h (21 ± 1 °C, 40 mbar) to 7.3 L/m(2) h (29 ± 1 °C, 100 mbar) after slight fluctuations and remained constant for the duration of the experiments (almost 3 months). An increase in biofouling layer thickness and a variable biofouling layer structure were observed over time by optical coherence tomography and confocal laser scanning microscopy. The presence of eukaryotic organisms in the biofouling layer was observed by light microscopy and the microbial community structure of the biofouling layer was analyzed by sequences of 16S rRNA genes. The magnitude of permeate flux was associated with the combined effect of the biofouling layer thickness and structure. Changes in the biofouling layer structure were attributed to (1) the movement and predation behaviour of the eukaryotic organisms which increased the heterogeneous nature of the biofouling layer; (2) the bacterial debris generated by eukaryotic predation activity which reduced porosity; (3) significant shifts of the dominant bacterial species over time that may have influenced the biofouling layer structure. As expected, most of the particles and colloids in the feed seawater were removed by the GDM process, which led to a lower RO fouling potential. However, the dissolved organic carbon in the

  2. Protecting nickel with graphene spin-filtering membranes: A single layer is enough

    Energy Technology Data Exchange (ETDEWEB)

    Martin, M.-B.; Dlubak, B.; Piquemal-Banci, M.; Collin, S.; Petroff, F.; Anane, A.; Fert, A.; Seneor, P. [Unité Mixte de Physique CNRS/Thales, 1 Avenue Augustin Fresnel, 91767 Palaiseau, France and Université Paris Sud, 91405 Orsay (France); Weatherup, R. S.; Hofmann, S.; Robertson, J. [Department of Engineering, University of Cambridge, Cambridge CB21PZ (United Kingdom); Yang, H. [IBS Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Department of Energy Science, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Blume, R. [Helmholtz-Zentrum Berlin fur Materialien und Energie, 12489 Berlin (Germany); Schloegl, R. [Department of Inorganic Chemistry, Fritz Haber Institute of the Max Planck Society, Faradayweg 4-6, 14195 Berlin (Germany)

    2015-07-06

    We report on the demonstration of ferromagnetic spin injectors for spintronics which are protected against oxidation through passivation by a single layer of graphene. The graphene monolayer is directly grown by catalytic chemical vapor deposition on pre-patterned nickel electrodes. X-ray photoelectron spectroscopy reveals that even with its monoatomic thickness, monolayer graphene still efficiently protects spin sources against oxidation in ambient air. The resulting single layer passivated electrodes are integrated into spin valves and demonstrated to act as spin polarizers. Strikingly, the atom-thick graphene layer is shown to be sufficient to induce a characteristic spin filtering effect evidenced through the sign reversal of the measured magnetoresistance.

  3. Cake layers and long filtration times protect ceramic micro-filtration membranes for fouling

    NARCIS (Netherlands)

    Lu, J.

    2013-01-01

    The objective of this research was to decrease membrane fouling of a ceramic microfiltration system and at the same time increase the recovery. A conventional operation in micro- and ultrafiltration is an in-line coagulation and a frequent hydraulic backwash. The idea about these frequent backwashes

  4. Bio-layer management in anaerobic membrane bioreactors for wastewater treatment

    NARCIS (Netherlands)

    Jeison, D.; Lier, van J.B.

    2006-01-01

    Membrane separation technology represents an alternative way to achieve biomass retention in anaerobic bioreactors for wastewater treatment. Due to high biomass concentrations of anaerobic reactors, cake formation is likely to represent a major cause of flux decline. In the presented research,

  5. Irreversible membrane fouling abatement through pre-deposited layer of hierarchical porous carbons

    KAUST Repository

    Hamad, Juma

    2014-11-01

    In this work, dual-templated hierarchical porous carbons (HPCs), produced from a coupled ice-hard templating approach, are shown to be a highly effective solution to the commonly occurring problem of irreversible fouling of low-pressure membranes used for pre-treatment in wastewater reuse. For the first time, dual-templated HPCs, along with their respective counterparts - single-templated meso-porous carbon (MPCs) (without macropores) - are tested in terms of their fouling reduction capacity and ability to remove different effluent organic matter fractions present in wastewater and compared with a commercially available powdered activated carbon (PAC). The synthesized HPCs provided exceptional fouling abatement, a 4-fold higher fouling reduction as compared to the previously reported best performing commercial PAC and ~2.5-fold better fouling reduction than their respective mesoporous counterpart. Thus, it is shown that not only mesoporosity, but macroporosity is also necessary to achieve high fouling reduction, thus emphasizing the need for dual templating. In the case of HPCs, the pre-deposition technique is also found to outperform the traditional sorbent-feed mixing approach, mainly in terms of removal of fouling components. Based on their superior performance, a high permeability (ultra-low-pressure) membrane consisting of the synthesized HPC pre-deposited on a large pore size membrane support (0.45μm membrane), is shown to give excellent pre-treatment performance for wastewater reuse application. © 2014 Elsevier Ltd.

  6. Electrochemical analysis of ion-exchange membranes with respect to a possible use in electrodialytic decontamination of soil polluted with heavy metals

    DEFF Research Database (Denmark)

    Hansen, Henrik; Ottosen, Lisbeth M.; Laursen, Søren

    1997-01-01

    Transport numbers in different metal chloride solutions were estimated using the emf method for two ion-exchange membranes: Ionics CR67 HMR412 (cation-exchange membrane) and Ionics AR204 SXRA 7639 (anion-exchange membrane). The cation-exchange membrane was found to work nearly ideally for Na...... experiments taken as a simplified simulation of the electrokinetic decontamination method showed that it was possible to remove all ions in the simulated soil volume, with a sharp increase in the potential difference over the soil volume as a result, and that it was possible to control the metal content...

  7. Encapsulated Islet Transplantation: Where Do We Stand?

    Science.gov (United States)

    Vaithilingam, Vijayaganapathy; Bal, Sumeet; Tuch, Bernard E

    2017-01-01

    Transplantation of pancreatic islets encapsulated within immuno-protective microcapsules is a strategy that has the potential to overcome graft rejection without the need for toxic immunosuppressive medication. However, despite promising preclinical studies, clinical trials using encapsulated islets have lacked long-term efficacy, and although generally considered clinically safe, have not been encouraging overall. One of the major factors limiting the long-term function of encapsulated islets is the host's immunological reaction to the transplanted graft which is often manifested as pericapsular fibrotic overgrowth (PFO). PFO forms a barrier on the capsule surface that prevents the ingress of oxygen and nutrients leading to islet cell starvation, hypoxia and death. The mechanism of PFO formation is still not elucidated fully and studies using a pig model have tried to understand the host immune response to empty alginate microcapsules. In this review, the varied strategies to overcome or reduce PFO are discussed, including alginate purification, altering microcapsule geometry, modifying alginate chemical composition, co-encapsulation with immunomodulatory cells, administration of pharmacological agents, and alternative transplantation sites. Nanoencapsulation technologies, such as conformal and layer-by-layer coating technologies, as well as nanofiber, thin-film nanoporous devices, and silicone based NanoGland devices are also addressed. Finally, this review outlines recent progress in imaging technologies to track encapsulated cells, as well as promising perspectives concerning the production of insulin-producing cells from stem cells for encapsulation.

  8. Laboratory measurements of nitric oxide release from forest soil with a thick organic layer under different understory types

    Directory of Open Access Journals (Sweden)

    A. Bargsten

    2010-05-01

    Full Text Available Nitric oxide (NO plays an important role in the photochemistry of the troposphere. NO from soil contributes up to 40% to the global budget of atmospheric NO. Soil NO emissions are primarily caused by biological activity (nitrification and denitrification, that occurs in the uppermost centimeter of the soil, a soil region often characterized by high contents of organic material. Most studies of NO emission potentials to date have investigated mineral soil layers. In our study we sampled soil organic matter under different understories (moss, grass, spruce and blueberries in a humid mountainous Norway spruce forest plantation in the Fichtelgebirge (Germany. We performed laboratory incubation and flushing experiments using a customized chamber technique to determine the response of net potential NO flux to physical and chemical soil conditions (water content and temperature, bulk density, particle density, pH, C/N ratio, organic C, soil ammonium, soil nitrate. Net potential NO fluxes (in terms of mass of N from soil samples taken under different understories ranged from 1.7–9.8 ng m−2 s−1 (soil sampled under grass and moss cover, 55.4–59.3 ng m−2 s−1 (soil sampled under spruce cover, and 43.7–114.6 ng m−2 s−1 (soil sampled under blueberry cover at optimum water content and a soil temperature of 10 °C. The water content for optimum net potential NO flux ranged between 0.76 and 0.8 gravimetric soil moisture for moss covered soils, between 1.0 and 1.1 for grass covered soils, 1.1 and 1.2 for spruce covered soils, and 1.3 and 1.9 for blueberry covered soils. Effects of soil physical and chemical characteristics on net potential NO flux were statistically significant (0.01 probability level only for NH4+. Therefore, as an alternative explanation for the differences in soil biogenic NO emission we consider more biological factors like understory

  9. Wire rod coating process of gas diffusion layers fabrication for proton exchange membrane fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Kannan, A.M.; Sadananda, S.; Parker, D.; Munukutla, L. [Electronic Systems Department, Arizona State University, 7001 E Williams Field Road, Mesa, AZ 85212 (United States); Wertz, J. [Hollingsworth and Vose Co., A.K. Nicholson Research Lab, 219 Townsend Road West Groton, MA 01472 (United States); Thommes, M. [Quantachrome Instruments, 1900 Corporate Drive, Boynton Beach, FL 33426 (United States)

    2008-03-15

    Gas diffusion layers (GDLs) were fabricated using non-woven carbon paper as a macro-porous layer substrate developed by Hollingsworth and Vose Company. A commercially viable coating process was developed using wire rod for coating micro-porous layer by a single pass. The thickness as well as carbon loading in the micro-porous layer was controlled by selecting appropriate wire thickness of the wire rod. Slurry compositions with solid loading as high as 10 wt.% using nano-chain and nano-fiber type carbons were developed using dispersion agents to provide cohesive and homogenous micro-porous layer without any mud-cracking. The surface morphology, wetting characteristics and pore size distribution of the wire rod coated GDLs were examined using FESEM, Goniometer and Hg porosimetry, respectively. The GDLs were evaluated in single cell PEMFC under various operating conditions (temperature and RH) using hydrogen and air as reactants. It was observed that the wire rod coated micro-porous layer with 10 wt.% nano-fibrous carbon based GDLs showed the highest fuel cell performance at 85 C using H{sub 2} and air at 50% RH, compared to all other compositions. (author)

  10. Broadband pH-Sensing Organic Transistors with Polymeric Sensing Layers Featuring Liquid Crystal Microdomains Encapsulated by Di-Block Copolymer Chains.

    Science.gov (United States)

    Seo, Jooyeok; Song, Myeonghun; Jeong, Jaehoon; Nam, Sungho; Heo, Inseok; Park, Soo-Young; Kang, Inn-Kyu; Lee, Joon-Hyung; Kim, Hwajeong; Kim, Youngkyoo

    2016-09-14

    We report broadband pH-sensing organic field-effect transistors (OFETs) with the polymer-dispersed liquid crystal (PDLC) sensing layers. The PDLC layers are prepared by spin-coating using ethanol solutions containing 4-cyano-4'-pentyl-biphenyl (5CB) and a diblock copolymer (PAA-b-PCBOA) that consists of LC-philic block [poly(4-cyano-biphenyl-4-oxyundecyl acrylate) (PCBOA)] and acrylic acid block [poly(acrylic acid) (PAA)]. The spin-coated sensing layers feature of 5CB microdomains (pH with only small amounts (10-40 μL) of analyte solutions in both static and dynamic perfusion modes. The positive drain current change is measured for acidic solutions (pH pH > 7) result in the negative change of drain current. The drain current trend in the present PDLC-i-OFET devices is explained by the shrinking-expanding mechanism of the PAA chains in the diblock copolymer layers.

  11. Encapsulation by Janus spheroids

    OpenAIRE

    Li, Wei; Liu, Ya; Brett, Genevieve; Gunton, James D.

    2011-01-01

    The micro/nano encapsulation technology has acquired considerable attention in the fields of drug delivery, biomaterial engineering, and materials science. Based on recent advances in chemical particle synthesis, we propose a primitive model of an encapsulation system produced by the self-assembly of Janus oblate spheroids, particles with oblate spheroidal bodies and two hemi-surfaces coded with dissimilar chemical properties. Using Monte Carlo simulation, we investigate the encapsulation sys...

  12. Theoretical and Experimental Substantiation for Applicability of a Damping Layer in a Foundation Slab Placed on Soil Bed

    Directory of Open Access Journals (Sweden)

    Kiselev Nikita

    2016-01-01

    Full Text Available Authors present the results of studies of innovative foundation structure. The idea of how to increase the operational quality of foundations and reduce the costs due to rational loading of the soil bed is numerically simulated. It is shown that the bending moment in the foundation slab depends on uneven settlements of the soil bed. It is proposed to stabilize the deformable soil bed by the damping layer placed under the slab footing in the zones with minor settlements. Considered is the concept of the damping layer in the foundation slab placed on the soil bed (DLS. The in-situ test for DLS-clayey bed interaction is described. Given are the results obtained after the experiments for DLS performance. The result of DLS implementation in designing the foundation of the 22-storeyed block of flats is considered. The expediency of DLS in comparison to standard foundations is presented.

  13. How Do Polyethylene Glycol and Poly(sulfobetaine) Hydrogel Layers on Ultrafiltration Membranes Minimize Fouling and Stay Stable in Cleaning Chemicals?

    KAUST Repository

    Le, Ngoc Lieu

    2017-05-18

    We compare the efficiency of grafting polyethylene glycol (PEG) and poly(sulfobetaine) hydrogel layer on poly(ether imide) (PEI) hollow-fiber ultrafiltration membrane surfaces in terms of filtration performance, fouling minimization and stability in cleaning solutions. Two previously established different methods toward the two different chemistries (and both had already proven to be suited to reduce fouling significantly) are applied to the same PEI membranes. The hydrophilicity of PEI membranes is improved by the modification, as indicated by the change of contact angle value from 89° to 68° for both methods, due to the hydration layer formed in the hydrogel layers. Their pure water flux declines because of the additional permeation barrier from the hydrogel layers. However, these barriers increase protein rejection. In the exposure at a static condition, grafting PEG or poly(sulfobetaine) reduces protein adsorption to 23% or 11%, respectively. In the dynamic filtration, the hydrogel layers minimizes the flux reduction and increases the reversibility of fouling. Compared to the pristine PEI membrane that can recover its flux to 42% after hydraulic cleaning, the PEG and poly(sulfobetaine) grafted membranes can recover their flux up to 63% and 94%, respectively. Stability tests show that the poly(sulfobetaine) hydrogel layer is stable in acid, base and chlorine solutions, whereas the PEG hydrogel layer suffers alkaline hydrolysis in base and oxidation in chlorine conditions. With its chemical stability and pronounced capability of minimizing fouling, especially irreversible fouling, protective poly(sulfobetaine) hydrogel layers have great potential for various membrane-based applications.

  14. Changes in the physical properties of the dynamic layer and its correlation with permeate quality in a self-forming dynamic membrane bioreactor.

    Science.gov (United States)

    Guan, Dao; Dai, Ji; Watanabe, Yoshimasa; Chen, Guanghao

    2018-09-01

    The self-forming dynamic membrane bioreactor (SFDMBR) is a biological wastewater treatment technology based on the conventional membrane bioreactor (MBR) with membrane material modification to a large pore size (30-100 μm). This modification requires a dynamic layer formed by activated sludge to provide effective filtration function for high-quality permeate production. The properties of the dynamic layer are therefore important for permeate quality in SFDMBRs. The interaction between the structure of the dynamic layer and the performance of SFDMBRs is little known but understandably complex. To elucidate the interaction, a lab-scale SFDMBR system coupled with a nylon woven mesh as the supporting material was operated. After development of a mature dynamic layer, excellent solid-liquid separation was achieved, as evidenced by a low permeate turbidity of less than 2 NTU. The permeate turbidity stayed below this level for nearly 80 days. In the fouling phase, the dynamic layer was compressed with an increase in the trans-membrane pressure and the quality of the permeate kept deteriorating until the turbidity exceeded 10 NTU. The investigation revealed that the majority of permeate particles were dissociated from the dynamic layer on the back surface of the supporting material, which is caused by the compression, breakdown, and dissociation of the dynamic layer. This phenomenon was observed directly in experiment instead of model prediction or conjecture for the first time. Copyright © 2018 Elsevier Ltd. All rights reserved.

  15. Modelling porous active layer electrodes of proton exchange membrane fuel cells; Modelisation des couches actives d'electrodes volumiques de piles a combustible a membrane echangeuse de protons

    Energy Technology Data Exchange (ETDEWEB)

    Bultel, Yann

    1997-07-01

    This work focusses on the modeling of mass, charge and heat transfer in the active layers of the volume electrodes of proton exchange membrane fuel cells (PEMFC). A first part describes the structure of fuel cells and the physico-chemical processes taking place at the electrodes. An analysis of the classical models encountered in the literature shows that they all assume that the electro-catalysts is uniformly distributed in a plane or in volume. In a second part, the modeling of mass and charge transport phenomena has been carried out with a numerical calculation software which uses the finite-elements method and which allows to take into consideration the discrete distribution of the catalyst in nano-particulates. The simulations show the limitations of the catalyst use because of the diffusion and ionic ohmic drop both at the electrolyte and particulates scale. In order to improve the modeling of PEMFC fuel cells, the classical models have been modified to consider these local contributions. They require only simple numerical methods, like the finite-differences one. When applied to the oxygen reduction at the cathode or to the hydrogen oxidation at the anode, these models allow to determine the kinetics parameters (exchange current densities and slopes of the Tafel lines) after correction of the active layer diffusion. A modeling of the heat transfers at the active layers scale is proposed. The model takes into account the convective heat transfers between the solid phases and the gas, the electro-osmosis water transfer, and the generation of heat by joule effect and by the electrochemical reactions. Finally, the last chapter presents a study of the reaction mechanisms in the case of porous electrodes using the impedances method. Numerical and analytical models have been developed to calculate the electrode impedances and are applied to the study of oxygen reduction and hydrogen oxidation. (J.S.)

  16. Electromotive force and impedance studies of cellulose acetate membranes: Evidence for two binding sites for divalent cations and for an alveolar structure of the skin layer

    DEFF Research Database (Denmark)

    Smith Sørensen, T.; Jensen, J.B.; Malmgren-Hansen, B.

    1991-01-01

    asymmetic membranes. The skin layer in asymmetric membranes is assumed to have properties similar to dense membranes. The EMF measurements were interpreted by means of a Donnan-Nernst-Planck (Teorell-Meyer-Sievers) model, which functions quite well due to the low fixed charge in the membrane. The membrane...... diffusion potential is calculated by the Henderson method and in some cases by solving transcendental equations according to Planck, Pleijel and Schlogl. There is no great difference between the membrane potentials calculated by the two methods, but the ion profiles and the actual rates of electrodiffusion...... of ca. 30 in the alveolar phase is also supported by a simple dielectric calculation of the Nernst distribution of mono- and divalent ions between external water and the alveolar solution. Corrections for activity coefficients only seems important above 0.5 M. The Onsager-Samaras dielectric repulsion...

  17. Antibacterial efficacy of triple-layered poly(lactic-co-glycolic acid)/nanoapatite/lauric acid guided bone regeneration membrane on periodontal bacteria.

    Science.gov (United States)

    Saarani, Nur Najiha; Jamuna-Thevi, Kalitheerta; Shahab, Neelam; Hermawan, Hendra; Saidin, Syafiqah

    2017-05-31

    A guided bone regeneration (GBR) membrane has been extensively used in the repair and regeneration of damaged periodontal tissues. One of the main challenges of GBR restoration is bacterial colonization on the membrane, constitutes to premature membrane degradation. Therefore, the purpose of this study was to investigate the antibacterial efficacy of triple-layered GBR membrane composed of poly(lactic-co-glycolic acid) (PLGA), nanoapatite (NAp) and lauric acid (LA) with two types of Gram-negative periodontal bacteria, Fusobacterium nucleatum and Porphyromonas gingivalis through a disc diffusion and bacterial count tests. The membranes exhibited a pattern of growth inhibition and killing effect against both bacteria. The increase in LA concentration tended to increase the bactericidal activities which indicated by higher diameter of inhibition zone and higher antibacterial percentage. It is shown that the incorporation of LA into the GBR membrane has retarded the growth and proliferation of Gram-negative periodontal bacteria for the treatment of periodontal disease.

  18. A Highly Ion-Selective Zeolite Flake Layer on Porous Membranes for Flow Battery Applications.

    Science.gov (United States)

    Yuan, Zhizhang; Zhu, Xiangxue; Li, Mingrun; Lu, Wenjing; Li, Xianfeng; Zhang, Huamin

    2016-02-24

    Zeolites are crystalline microporous aluminosilicates with periodic arrangements of cages and well-defined channels, which make them very suitable for separating ions of different sizes, and thus also for use in battery applications. Herein, an ultra-thin ZSM-35 zeolite flake was introduced onto a poly(ether sulfone) based porous membrane. The pore size of the zeolite (ca. 0.5 nm) is intermediary between that of hydrated vanadium ions (>0.6 nm) and protons (99 % and an energy efficiency of >81 % at 200 mA cm(-2), which is by far the highest value ever reported. These convincing results indicate that zeolite-coated membranes are promising in battery applications. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Dark gray soils on two-layered deposits in the north of Tambov Plain: Agroecology, properties, and diagnostics

    Science.gov (United States)

    Zaidelman, F. R.; Nikiforova, A. S.; Stepantsova, L. V.; Volokhina, V. P.

    2012-05-01

    Dark gray soils in the Tambov Plain are developed from the light-textured glaciofluvial deposits underlain by the calcareous loam. Their morphology, water regime, and productivity are determined by the depth of the slightly permeable calcareous loamy layer, relief, and the degree of gleyzation. The light texture of the upper layer is responsible for its weak structure, high density, the low content of productive moisture, and the low water-holding capacity. If the calcareous loam is at a depth of 100-130 cm, dark gray soils are formed; if it lies at a depth of 40-70 cm, temporary perched water appears in the profile, and dark gray contact-gleyed soils are formed. Their characteristic pedofeatures are skeletans in the upper layers, calcareous nodules in the loamy clay layer, and iron nodules in the podzolized humus and podzolic horizons. The appearance of Fe-Mn concretions is related to gleyzation. The high yield of winter cereals is shown to be produced on the dark gray soils; the yields of spring crops are less stable. Spring cereals should not be grown on the contact-gleyed dark gray soils.

  20. FEM Simulation of Influence of Protective Encapsulation on MEMS Pressure Sensor

    DEFF Research Database (Denmark)

    Yao, Qingshan; Janting, Jakob; Branebjerg, Jens

    2003-01-01

    The objective of the work is to evaluate the feasibility of packaging a MEMS silicon pressure sensor by using either a polymer encapsulation or a combination of a polymer encapsulation and a metallic protection Membrane (fig. 1). The potential application of the protected sensor is for harsh...... environments. Several steps of simulation are carried out:1) Comparisons of the sensitivities are made among the non-encapsulated silicon sensor, the polymer encapsulated and polymer with metal encapsulated sensor. This is for evaluating whether the encapsulating materials reduce the pressure sensitivity...... whether the metallic membrane / coating will peel off when applying the maximum pressure, which is 4000 bar leading to high shear stress between the metallic membrane and the polymer encapsulation material.3) Thermal calculations are made to evaluate the influence of the environment on the packaged sensor...

  1. Polyurethane Ionophore-Based Thin Layer Membranes for Voltammetric Ion Activity Sensing.

    Science.gov (United States)

    Cuartero, Maria; Crespo, Gaston A; Bakker, Eric

    2016-06-07

    We report on a plasticized polyurethane ionophore-based thin film material (of hundreds of nanometer thickness) for simultaneous voltammetric multianalyte ion activity detection triggered by the oxidation/reduction of an underlying poly(3-octylthiophene) film. This material provides excellent mechanical, physical, and chemical robustness compared to other polymers. Polyurethane films did not exhibit leaching of lipophilic additives after rinsing with a direct water jet and exhibited resistance to detachment from the underlying electrode surface, resulting in a voltammetric current response with less than acrylate) ionophore-based membranes of the same thickness and composition exhibited a significant deterioration of the signal after identical treatment. While previously reported works emphasized fundamental advancement of multi-ion detection with multi-ionophore-based thin films, polyurethane thin membranes allow one to achieve real world measurements without sacrificing analytical performance. Indeed, polyurethane membranes are demonstrated to be useful for the simultaneous determination of potassium and lithium in undiluted human serum and blood with attractive precision.

  2. Characterization of soil bacterial, archaeal and fungal communities inhabiting archaeological human-impacted layers at Monte Iato settlement (Sicily, Italy).

    Science.gov (United States)

    Siles, José A; Öhlinger, Birgit; Cajthaml, Tomas; Kistler, Erich; Margesin, Rosa

    2018-01-30

    Microbial communities in human-impacted soils of ancient settlements have been proposed to be used as ecofacts (bioindicators) of different ancient anthropogenic activities. In this study, bacterial, archaeal and fungal communities inhabiting soil of three archaic layers, excavated at the archaeological site on Monte Iato (Sicily, Italy) and believed to have been created in a chronological order in archaic times in the context of periodic cultic feasts, were investigated in terms of (i) abundance (phospholipid fatty acid (PLFA) analysis and quantitative PCR)), (ii) carbon(C)-source consumption patterns (Biolog-Ecoplates) and (iii) diversity and community composition (Illumina amplicon sequencing). PLFA analyses demonstrated the existence of living bacteria and fungi in the soil samples of all three layers. The upper layer showed increased levels of organic C, which were not concomitant with an increment in the microbial abundance. In taxonomic terms, the results indicated that bacterial, archaeal and fungal communities were highly diverse, although differences in richness or diversity among the three layers were not detected for any of the communities. However, significantly different microbial C-source utilization patterns and structures of bacterial, archaeal and fungal communities in the three layers confirmed that changing features of soil microbial communities reflect different past human activities.

  3. Determining time-weighted average concentrations of nitrate and ammonium in freshwaters using DGT with ion exchange membrane-based binding layers

    DEFF Research Database (Denmark)

    Huang, Jianyin; Bennett, William W.; Welsh, David T.

    2016-01-01

    Commercially-available AMI-7001 anion exchange and CMI-7000 cation exchange membranes were utilised as binding layers for DGT measurements of NO3-N and NH4-N in freshwaters. These ion exchange membranes are easier to prepare and handle than DGT binding layers consisting of hydrogels cast with ion...... exchange resins. The membranes showed good uptake and elution efficiencies for both NO3-N and NH4-N. The membrane-based DGTs are suitable for pH 3.5-8.5 and ionic strength ranges (0.0001-0.014 and 0.0003-0.012 mol L−1 as NaCl for the AMI-7001 and CMI-7000 membrane, respectively) typical of most natural...... freshwaters. The binding membranes had high intrinsic binding capacities for NO3-N and NH4-N of 911 ± 88 μg and 3512 ± 51 μg, respectively. Interferences from the major competing ions for membrane-based DGTs are similar to DGTs employing resin-based binding layers but with slightly different selectivity...

  4. Hemocompatibility of poly(vinylidene fluoride) membrane grafted with network-like and brush-like antifouling layer controlled via plasma-induced surface PEGylation.

    Science.gov (United States)

    Chang, Yung; Shih, Yu-Ju; Ko, Chao-Yin; Jhong, Jheng-Fong; Liu, Ying-Ling; Wei, Ta-Chin

    2011-05-03

    In this work, the hemocompatibility of PEGylated poly(vinylidene fluoride) (PVDF) microporous membranes with varying grafting coverage and structures via plasma-induced surface PEGylation was studied. Network-like and brush-like PEGylated layers on PVDF membrane surfaces were achieved by low-pressure and atmospheric plasma treatment. The chemical composition, physical morphology, grafting structure, surface hydrophilicity, and hydration capability of prepared membranes were determined to illustrate the correlations between grafting qualities and hemocompatibility of PEGylated PVDF membranes in contact with human blood. Plasma protein adsorption onto different PEGylated PVDF membranes from single-protein solutions and the complex medium of 100% human plasma were measured by enzyme-linked immunosorbent assay (ELISA) with monoclonal antibodies. Hemocompatibility of the PEGylated membranes was evaluated by the antifouling property of platelet adhesion observed by scanning electron microscopy (SEM) and the anticoagulant activity of the blood coagulant determined by testing plasma-clotting time. The control of grafting structures of PEGylated layers highly regulates the PVDF membrane to resist the adsorption of plasma proteins, the adhesion of platelets, and the coagulation of human plasma. It was found that PVDF membranes grafted with brush-like PEGylated layers presented higher hydration capability with binding water molecules than with network-like PEGylated layers to improve the hemocompatible character of plasma protein and blood platelet resistance in human blood. This work suggests that the hemocompatible nature of grafted PEGylated polymers by controlling grafting structures gives them great potential in the molecular design of antithrombogenic membranes for use in human blood.

  5. The role of soil layers in preventing ground water pollution with 17ß-estradiol hormone (E 2

    Directory of Open Access Journals (Sweden)

    A’zam Golzari

    2016-03-01

    Full Text Available Background: Estrogens include estoril (E3, estradiol and estrone (E1. These chemicals are produced in human and animal bodies as well as in synthetic chemicals (drugs. Estrogens can enter water sources in different ways. When these chemicals enter the human body through water and wastewater, they have the ability to mimic or disrupt the normal estrogen activities in humans and animals. Estrogens in wastewater are able to pass soil layers and contaminate groundwater. Therefore, in this study, the removal of the hormone 17ß-estradiol (E2 as a representative of estrogens in three types of soils was studied. The selection was chosen in respect to the importance of entering the hormone into groundwater through the soil. Methods: This study was an experimental study in which the removal of the hormone E2 from different depths of three types of soils was experimented. The soils were consisted of two different textures, the silty sandy clay and the silty sand with gravel. The hormone E2 was diluted and injected into the drilled holes. Soils were characterized in the soil mechanics laboratory. Hormone extraction from the soils was performed using a centrifuge and analyzed with the Elecsys device. The results were analyzed using the IBM SPSS version 22 software. Results: The results showed that the removal rates of hormone E2 in the three types of soils were higher than 99.5%, and the removal rate in the silty sand was more than the others. In all three soil samples, the removal rates in the first layer were high. The average injected hormone in the soil decreased from 3500 to 3112 ng/l. The results showed that the adhesion and plasticity of the soil had also affected the removal rates. Conclusion: Results showed that the soil plays a significant role in the removal of E2 hormone and this hormone was reduced or eliminated in the first layers of the soils. Thus, the risk of groundwater contamination is low.

  6. Encapsulation plant at Forsmark

    International Nuclear Information System (INIS)

    Nystroem, Anders

    2007-08-01

    SKB has already carried out a preliminary study of an encapsulation plant detached from Clab (Central interim storage for spent fuels). This stand-alone encapsulation plant was named FRINK and its assumed siting was the above-ground portion of the final repository, irrespective of the repository's location. The report previously presented was produced in cooperation with BNFL Engineering Ltd in Manchester and the fuel reception technical solution was examined by Gesellschaft fuer Nuklear-Service mbH (GNS) in Hannover and by Societe Generale pour les Techniques Nouvelles (SGN) in Paris. This report is an update of the earlier preliminary study report and is based on the assumption that the encapsulation plant and also the final repository will be sited in the Forsmark area. SKB's main alternative for siting the encapsulation plant is next to Clab. Planning of this facility is ongoing and technical solutions from the planning work have been incorporated in this report. An encapsulation plant placed in proximity to any final repository in Forsmark forms part of the alternative presentation in the application for permission to construct and operate an installation at Clab. The main technical difference between the planned encapsulation plant at Clab and an encapsulation plant at a final repository at Forsmark is how the fuel is managed and prepared before actual encapsulation. Fuel reception at the encapsulation plant in Forsmark would be dry, i.e. there would be no water-filled pools at the facility. Clab is used for verificatory fuel measurements, sorting and drying of the fuel before transport to Forsmark. This means that Clab will require a measure of rebuilding and supplementary equipment. In purely technical terms, the prospects for building an encapsulation plant sited at Forsmark are good. A description of the advantages and drawbacks of siting the encapsulation plant at Clab as opposed to any final repository at Forsmark is presented in a separate report

  7. Encapsulation plant at Forsmark

    Energy Technology Data Exchange (ETDEWEB)

    Nystroem, Anders

    2007-08-15

    SKB has already carried out a preliminary study of an encapsulation plant detached from Clab (Central interim storage for spent fuels). This stand-alone encapsulation plant was named FRINK and its assumed siting was the above-ground portion of the final repository, irrespective of the repository's location. The report previously presented was produced in cooperation with BNFL Engineering Ltd in Manchester and the fuel reception technical solution was examined by Gesellschaft fuer Nuklear-Service mbH (GNS) in Hannover and by Societe Generale pour les Techniques Nouvelles (SGN) in Paris. This report is an update of the earlier preliminary study report and is based on the assumption that the encapsulation plant and also the final repository will be sited in the Forsmark area. SKB's main alternative for siting the encapsulation plant is next to Clab. Planning of this facility is ongoing and technical solutions from the planning work have been incorporated in this report. An encapsulation plant placed in proximity to any final repository in Forsmark forms part of the alternative presentation in the application for permission to construct and operate an installation at Clab. The main technical difference between the planned encapsulation plant at Clab and an encapsulation plant at a final repository at Forsmark is how the fuel is managed and prepared before actual encapsulation. Fuel reception at the encapsulation plant in Forsmark would be dry, i.e. there would be no water-filled pools at the facility. Clab is used for verificatory fuel measurements, sorting and drying of the fuel before transport to Forsmark. This means that Clab will require a measure of rebuilding and supplementary equipment. In purely technical terms, the prospects for building an encapsulation plant sited at Forsmark are good. A description of the advantages and drawbacks of siting the encapsulation plant at Clab as opposed to any final repository at Forsmark is presented in a separate

  8. Soil surface organic layers in Arctic Alaska: spatial distribution, rates of formation, and microclimatic effects

    Science.gov (United States)

    Baughman, Carson; Mann, Daniel H.; Verbyla, David L.; Kunz, Michael L.

    2015-01-01

    Organic layers of living and dead vegetation cover the ground surface in many permafrost landscapes and play important roles in ecosystem processes. These soil surface organic layers (SSOLs) store large amounts of carbon and buffer the underlying permafrost and its contained carbon from changes in aboveground climate. Understanding the dynamics of SSOLs is a prerequisite for predicting how permafrost and carbon stocks will respond to warming climate. Here we ask three questions about SSOLs in a representative area of the Arctic Foothills region of northern Alaska: (1) What environmental factors control the thickness of SSOLs and the carbon they store? (2) How long do SSOLs take to develop on newly stabilized point bars? (3) How do SSOLs affect temperature in the underlying ground? Results show that SSOL thickness and distribution correlate with elevation, drainage area, vegetation productivity, and incoming solar radiation. A multiple regression model based on these correlations can simulate spatial distribution of SSOLs and estimate the organic carbon stored there. SSOLs develop within a few decades after a new, sandy, geomorphic surface stabilizes but require 500–700 years to reach steady state thickness. Mature SSOLs lower the growing season temperature and mean annual temperature of the underlying mineral soil by 8 and 3°C, respectively. We suggest that the proximate effects of warming climate on permafrost landscapes now covered by SSOLs will occur indirectly via climate's effects on the frequency, extent, and severity of disturbances like fires and landslides that disrupt the SSOLs and interfere with their protection of the underlying permafrost.

  9. A single dose of dexamethasone encapsulated in polyethylene glycol-coated polylactic acid nanoparticles attenuates cisplatin-induced hearing loss following round window membrane administration.

    Science.gov (United States)

    Sun, Changling; Wang, Xueling; Zheng, Zhaozhu; Chen, Dongye; Wang, Xiaoqin; Shi, Fuxin; Yu, Dehong; Wu, Hao

    2015-01-01

    This study aimed to investigate the sustained drug release properties and hearing protection effect of polyethylene glycol-coated polylactic acid (PEG-PLA) stealth nanoparticles loaded with dexamethasone (DEX). DEX was fabricated into PEG-PLA nanoparticles using an emulsion and evaporation technique, as previously reported. The DEX-loaded PEG-PLA nanoparticles (DEX-NPs) had a hydrodynamic diameter of 130±4.78 nm, and a zeta potential of -26.13±3.28 mV. The in vitro release of DEX from DEX-NPs lasted 24 days in phosphate buffered saline (pH 7.4), 5 days in artificial perilymph (pH 7.4), and 1 day in rat plasma. Coumarin 6-labeled NPs placed onto the round window membrane (RWM) of guinea pigs penetrated RWM quickly and accumulated to the organs of Corti, stria vascularis, and spiral ganglion cells after 1 hour of administration. The DEX-NPs locally applied onto the RWM of guinea pigs by a single-dose administration continuously released DEX in 48 hours, which was significantly longer than the free DEX that was cleared out within 12 hours after administration at the same dose. Further functional studies showed that locally administrated single-dose DEX-NPs effectively preserved outer hair cells in guinea pigs after cisplatin insult and thus significantly attenuated hearing loss at 4 kHz and 8 kHz frequencies when compared to the control of free DEX formulation. Histological analyses indicated that the administration of DEX-NPs did not induce local inflammatory responses. Therefore, prolonged delivery of DEX by PEG-PLA nanoparticles through local RWM diffusion (administration) significantly protected the hair cells and auditory function in guinea pigs from cisplatin toxicity, as determined at both histological and functional levels, suggesting the potential therapeutic benefits in clinical applications.

  10. Multi-omics of permafrost, active layer and thermokarst bog soil microbiomes.

    Science.gov (United States)

    Hultman, Jenni; Waldrop, Mark P; Mackelprang, Rachel; David, Maude M; McFarland, Jack; Blazewicz, Steven J; Harden, Jennifer; Turetsky, Merritt R; McGuire, A David; Shah, Manesh B; VerBerkmoes, Nathan C; Lee, Lang Ho; Mavrommatis, Kostas; Jansson, Janet K

    2015-05-14

    Over 20% of Earth's terrestrial surface is underlain by permafrost with vast stores of carbon that, once thawed, may represent the largest future transfer of carbon from the biosphere to the atmosphere. This process is largely dependent on microbial responses, but we know little about microbial activity in intact, let alone in thawing, permafrost. Molecular approaches have recently revealed the identities and functional gene composition of microorganisms in some permafrost soils and a rapid shift in functional gene composition during short-term thaw experiments. However, the fate of permafrost carbon depends on climatic, hydrological and microbial responses to thaw at decadal scales. Here we use the combination of several molecular 'omics' approaches to determine the phylogenetic composition of the microbial communities, including several draft genomes of novel species, their functional potential and activity in soils representing different states of thaw: intact permafrost, seasonally thawed active layer and thermokarst bog. The multi-omics strategy reveals a good correlation of process rates to omics data for dominant processes, such as methanogenesis in the bog, as well as novel survival strategies for potentially active microbes in permafrost.

  11. Use of Neutron Probe to Quantify the Soil Moisture Flux in Layers of Cultivated Soil by Chickpea

    International Nuclear Information System (INIS)

    El- Gendy, R.W.

    2008-01-01

    This work aims to use the neutron moisture meter and the soil moisture retention curve to quantify the soil moisture flux in the soil profile of Nubarria soil in Egypt at 15, 30, 45, and 60-cm depths during the growth season of Chickpea. This method depends on the use of in situ θ measurements via neutron moisture meter and soil matric suction using model of the soil moisture retention curve at different soil depths, which can be determined in situ. Total hydraulic potential values at the different soil depths were calculated as a function (θ) using the derivative model. The gradient of hydraulic potential at any soil depth can be obtained by detecting of the hydraulic potential within the soil profile. The soil water fluxes at the different soil depths were calculated using In situ measured unsaturated hydraulic conductivity and the gradient of hydraulic potential, which correlated with soil moisture contents as measured by neutron probe. Values of hydraulic potentials after and before irrigation indicate that the direction of soil moisture movement was downward after irrigation and was different before next irrigation. Collecting active roots for water absorption of chickpea were defined from direction of soil water movement from up and down to a certain soil depth was 19 cm depth from the soil surface. Active rooting depth was 53 cm depth, which separates between evapotranspiration and gravity effects The soil water fluxes after and before the next irrigation of chickpea were 1.2453, 0.8613, 0.8197 and 0.6588 cm/hr and 0.0037, - 0.0270,- 0.1341, and 0.2545 cm/hr at 15, 30, 45 and 60 cm depths, respectively. The negative values at 30 and 45 cm depth before the next irrigation indicates there were up ward movement for soil water flux, where finding collecting active roots for water absorption of chickpea at 19 cm depth. Direction of soil water movement, soil water flux, collecting active roots for water absorption and active rooting depth can be determined using

  12. Encapsulation of nuclear wastes

    International Nuclear Information System (INIS)

    Arnold, J.L.; Boyle, R.W.

    1978-01-01

    Toxic waste materials are encapsulated by the method wherein the waste material in liquid or finely divided solid form is uniformly dispersed in a vinyl ester resin or an unsaturated polyester and the resin cured under conditions that the exotherm does not rise above the temperature at which the integrity of the encapsulating material is destroyed

  13. Irrigation and Nitrogen Regimes Promote the Use of Soil Water and Nitrate Nitrogen from Deep Soil Layers by Regulating Root Growth in Wheat.

    Science.gov (United States)

    Liu, Weixing; Ma, Geng; Wang, Chenyang; Wang, Jiarui; Lu, Hongfang; Li, Shasha; Feng, Wei; Xie, Yingxin; Ma, Dongyun; Kang, Guozhang

    2018-01-01

    Unreasonably high irrigation levels and excessive nitrogen (N) supplementation are common occurrences in the North China Plain that affect winter wheat production. Therefore, a 6-yr-long stationary field experiment was conducted to investigate the effects of irrigation and N regimes on root development and their relationship with soil water and N use in different soil layers. Compared to the non-irrigated treatment (W0), a single irrigation at jointing (W1) significantly increased yield by 3.6-45.6%. With increases in water (W2, a second irrigation at flowering), grain yield was significantly improved by 14.1-45.3% compared to the W1 treatments during the drier growing seasons (2010-2011, 2012-2013, and 2015-2016). However, under sufficient pre-sowing soil moisture conditions, grain yield was not increased, and water use efficiency (WUE) decreased significantly in the W2 treatments during normal precipitation seasons (2011-2012, 2013-2014, and 2014-2015). Irrigating the soil twice inhibited root growth into the deeper soil depth profiles and thus weakened the utilization of soil water and NO 3 -N from the deep soil layers. N applications increased yield by 19.1-64.5%, with a corresponding increase in WUE of 66.9-83.9% compared to the no-N treatment (N0). However, there was no further increase in grain yield and the WUE response when N rates exceeded 240 and 180 kg N ha -1 , respectively. A N application rate of 240 kg ha -1 facilitated root growth in the deep soil layers, which was conducive to utilization of soil water and NO 3 -N and also in reducing the residual NO 3 -N. Correlation analysis indicated that the grain yield was significantly positively correlated with soil water storage (SWS) and nitrate nitrogen accumulation (SNA) prior to sowing. Therefore, N rates of 180-240 kg ha -1 with two irrigations can reduce the risk of yield loss that occurs due to reduced precipitation during the wheat growing seasons, while under better soil moisture conditions, a

  14. Spatial representation of organic carbon and active-layer thickness of high latitude soils in CMIP5 earth system models

    Energy Technology Data Exchange (ETDEWEB)

    Mishra, Umakant; Drewniak, Beth; Jastrow, Julie D.; Matamala, Roser M.; Vitharana, U. W. A.

    2017-08-01

    Soil properties such as soil organic carbon (SOC) stocks and active-layer thickness are used in earth system models (F.SMs) to predict anthropogenic and climatic impacts on soil carbon dynamics, future changes in atmospheric greenhouse gas concentrations, and associated climate changes in the permafrost regions. Accurate representation of spatial and vertical distribution of these soil properties in ESMs is a prerequisite for redudng existing uncertainty in predicting carbon-climate feedbacks. We compared the spatial representation of SOC stocks and active-layer thicknesses predicted by the coupled Modellntercomparison Project Phase 5 { CMIP5) ESMs with those predicted from geospatial predictions, based on observation data for the state of Alaska, USA. For the geospatial modeling. we used soil profile observations {585 for SOC stocks and 153 for active-layer thickness) and environmental variables (climate, topography, land cover, and surficial geology types) and generated fine-resolution (50-m spatial resolution) predictions of SOC stocks (to 1-m depth) and active-layer thickness across Alaska. We found large inter-quartile range (2.5-5.5 m) in predicted active-layer thickness of CMIP5 modeled results and small inter-quartile range (11.5-22 kg m-2) in predicted SOC stocks. The spatial coefficient of variability of active-layer thickness and SOC stocks were lower in CMIP5 predictions compared to our geospatial estimates when gridded at similar spatial resolutions (24.7 compared to 30% and 29 compared to 38%, respectively). However, prediction errors. when calculated for independent validation sites, were several times larger in ESM predictions compared to geospatial predictions. Primaly factors leading to observed differences were ( 1) lack of spatial heterogeneity in ESM predictions, (2) differences in assumptions concerning environmental controls, and (3) the absence of pedogenic processes in ESM model structures. Our results suggest that efforts to incorporate

  15. Reducing the bioavailability of PCBs in soil to plant by biochars assessed with triolein-embedded cellulose acetate membrane technique

    International Nuclear Information System (INIS)

    Wang, Yu; Wang, Yu-Jun; Wang, Lei; Fang, Guo-Dong; Cang, Long; Herath, H.M.S.K.; Zhou, Dong-Mei

    2013-01-01

    Coupling with triolein-embedded cellulose acetate membrane (TECAM) technique, hydroxypropyl β-cyclodextrins (HPCD) extraction method, and the greenhouse pot experiments, the influences of biochars on polychlorinated biphenyls (PCBs) bioavailability in soil to plant (Brassica chinensis L. and Daucus carota) were investigated. Addition of 2% biochars to soils significantly reduced the uptake of PCBs in plant, especially for di-, tri- and tetra-chlorobiphenyls. PCBs concentrations in the roots of B. chinensis and D. carota were reduced for 61.5–93.7%, and 12.7–62.4%, respectively in the presence of biochars. The kinetic study showed that in the soils amended with/without biochars, PCBs concentrations accumulated in TECAM, as well as in the HPCD extraction solution, followed significant linear relationships with those in plant roots. Application of biochars to soil is a potentially promising method to reduce PCBs bioavailability whereas TECAM technique can be a useful tool to predict the bioavailability of PCBs in soil. -- Highlights: ► Application of biochars significantly reduced the uptake of PCBs in plant. ► TECAM was a new and effective method to predict the PCBs bioavailability in soil. ► PCBs accumulated in TECAM followed significant linear relationships with plant. ► PCBs in TECAM were more similar with the plant uptake than HPCD solution. -- The reduced PCBs concentrations in plant roots by biochars show good linear relationship with those in TECAM

  16. Flat-plate solar array project. Volume 7: Module encapsulation

    Science.gov (United States)

    Cuddihy, E.; Coulbert, C.; Gupta, A.; Liang, R.

    1986-01-01

    The objective of the Encapsulation Task was to develop, demonstrate, and qualify photovoltaic (PV) module encapsulation systems that would provide 20 year (later decreased to 30 year) life expectancies in terrestrial environments, and which would be compatible with the cost and performance goals of the Flat-Plate Solar Array (FSA) Project. The scope of the Encapsulation Task included the identification, development, and evaluation of material systems and configurations required to support and protect the optically and electrically active solar cell circuit components in the PV module operating environment. Encapsulation material technologies summarized include the development of low cost ultraviolet protection techniques, stable low cost pottants, soiling resistant coatings, electrical isolation criteria, processes for optimum interface bonding, and analytical and experimental tools for evaluating the long term durability and structural adequacy of encapsulated modules. Field testing, accelerated stress testing, and design studies have demonstrated that encapsulation materials, processes, and configurations are available that meet the FSA cost and performance goals.

  17. The technology of layer-specific rotary soil cultivation for forest crops and equipment for its implementation

    Directory of Open Access Journals (Sweden)

    S. N. Orlovskiy

    2017-06-01

    Full Text Available Influence of existing methods and technologies of soil processing for forest crops on establishment and growth of cultivated tree species was studied. It was found that furrow plough processing of soil can interfere with the cultivated trees’ ecological peculiarities, because the furrow floor, where trees are planted, often constitutes the lower part of the turf or the upper part of the ashen-gray layers having unfavorable water-physical conditions and decreased crop-producing power. Whenever conifer trees grow on the bottom of a furrow excavated in medium and heavy clay loam, their growth is significantly decreased and accompanied by remarkable changes in morphology. Processing of shallow humus thickness soil with multiple cutter results in mixing of A0, A1 and A2 (ashen-gray layers. Consequently, the processed horizon obtains a lower amount of fertile substances than the vegetable soil on non-processed places. An apparatus for graded soil tillage, its construction, working principle and usage technology are described. The major peculiarity of the device consists in the ability not to crumbl the soil, but to shake down vegetable earth cut by subsurface plow from beneath. The technology involves removing roots and grass outside cultivated land, so that it cannot be then overgrown with weeds. It was found that exploitation of the device improves soil pulverization quality, enhances percentage of separates less than 10 mm and 10–50 mm, decreases content of the separate larger than 50 mm, and reduced specific energy output almost three-fold. Vertical displacement of control particles while soil processing with common cutter machines and the suggested device was studied. Establishment and growth of Siberian pine was determined in experimental productive cultures at different planting technologies. It was shown that under the suggested technology, forest plants furrow sowing can be done while soil processing, so that making nurseries becomes

  18. A single dose of dexamethasone encapsulated in polyethylene glycol-coated polylactic acid nanoparticles attenuates cisplatin-induced hearing loss following round window membrane administration

    Directory of Open Access Journals (Sweden)

    Sun CL

    2015-05-01

    Full Text Available Changling Sun,1,3,* Xueling Wang,1,* Zhaozhu Zheng,2 Dongye Chen,1 Xiaoqin Wang,2 Fuxin Shi,1 Dehong Yu,1 Hao Wu11Department of Otolaryngology–Head and Neck Surgery, Xinhua Hospital, Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, 2National Engineering Laboratory for Modern Silk, Soochow University, Suzhou, 3Department of Otolaryngology–Head and Neck Surgery, Affiliated Hospital of Jiangnan University, The Fourth People’s Hospital of Wuxi City, Wuxi, People’s Republic of China*These authors have contributed equally to this workAbstract: This study aimed to investigate the sustained drug release properties and hearing protection effect of polyethylene glycol-coated polylactic acid (PEG-PLA stealth nanoparticles loaded with dexamethasone (DEX. DEX was fabricated into PEG-PLA nanoparticles using an emulsion and evaporation technique, as previously reported. The DEX-loaded PEG-PLA nanoparticles (DEX-NPs had a hydrodynamic diameter of 130±4.78 nm, and a zeta potential of -26.13±3.28 mV. The in vitro release of DEX from DEX-NPs lasted 24 days in phosphate buffered saline (pH 7.4, 5 days in artificial perilymph (pH 7.4, and 1 day in rat plasma. Coumarin 6-labeled NPs placed onto the round window membrane (RWM of guinea pigs penetrated RWM quickly and accumulated to the organs of Corti, stria vascularis, and spiral ganglion cells after 1 hour of administration. The DEX-NPs locally applied onto the RWM of guinea pigs by a single-dose administration continuously released DEX in 48 hours, which was significantly longer than the free DEX that was cleared out within 12 hours after administration at the same dose. Further functional studies showed that locally administrated single-dose DEX-NPs effectively preserved outer hair cells in guinea pigs after cisplatin insult and thus significantly attenuated hearing loss at 4 kHz and 8

  19. Influence of surface properties of filtration-layer metal oxide on ceramic membrane fouling during ultrafiltration of oil/water emulsion

    KAUST Repository

    Lu, Dongwei

    2016-04-01

    In this work, ceramic ultrafiltration membranes deposited with different metal oxides (i.e., TiO2, Fe2O3, MnO2, CuO, and CeO2) of around 10 nm in thickness and similar roughness were tested for O/W emulsion treatment. Distinct membrane fouling tendency was observed, which closely correlated to the properties of the filtration-layer metal oxides (i.e. surface hydroxyl groups, hydrophilicity, surface charge, and adhesion energy for oil droplets). In consistent with the distinct bond strength of the surface hydroxyl groups, hydrophilicity of these common metal oxides are quite different. The differences in hydrophilicity consequently lead to different adhesion of these metal oxides towards oil droplets which consists very well with irreversible membrane fouling tendency. In addition, the surface charge of the metal oxide opposite to that of emulsion can help to alleviate irreversible membrane fouling in ultrafiltration. Highly hydrophilic Fe2O3 with lowest fouling tendency could be a potential filtration-layer material for the fabrication/modification of ceramic membranes for O/W emulsion treatment. To the best of our knowledge, this is the first study clearly showing the correlations between surface properties of filtration-layer metal oxides and ceramic membrane fouling tendency by O/W emulsion.

  20. Influence of Surface Properties of Filtration-Layer Metal Oxide on Ceramic Membrane Fouling during Ultrafiltration of Oil/Water Emulsion.

    Science.gov (United States)

    Lu, Dongwei; Zhang, Tao; Gutierrez, Leo; Ma, Jun; Croué, Jean-Philippe

    2016-05-03

    In this work, ceramic ultrafiltration membranes deposited with different metal oxides (i.e., TiO2, Fe2O3, MnO2, CuO, and CeO2) of around 10 nm in thickness and similar roughness were tested for O/W emulsion treatment. A distinct membrane fouling tendency was observed, which closely correlated to the properties of the filtration-layer metal oxides (i.e., surface hydroxyl groups, hydrophilicity, surface charge, and adhesion energy for oil droplets). Consistent with the distinct bond strength of the surface hydroxyl groups, hydrophilicity of these common metal oxides is quite different. The differences in hydrophilicity consequently lead to different adhesion of these metal oxides toward oil droplets, consistent with the irreversible membrane fouling tendency. In addition, the surface charge of the metal oxide opposite to that of emulsion can help to alleviate irreversible membrane fouling in ultrafiltration. Highly hydrophilic Fe2O3 with the lowest fouling tendency could be a potential filtration-layer material for the fabrication/modification of ceramic membranes for O/W emulsion treatment. To the best of our knowledge, this is the first study clearly showing the correlations between surface properties of filtration-layer metal oxides and ceramic membrane fouling tendency by O/W emulsion.

  1. Influence of surface properties of filtration-layer metal oxide on ceramic membrane fouling during ultrafiltration of oil/water emulsion

    KAUST Repository

    Lu, Dongwei; Zhang, Tao; Gutierrez, Leo; Ma, Jun; Croue, Jean-Philippe

    2016-01-01

    In this work, ceramic ultrafiltration membranes deposited with different metal oxides (i.e., TiO2, Fe2O3, MnO2, CuO, and CeO2) of around 10 nm in thickness and similar roughness were tested for O/W emulsion treatment. Distinct membrane fouling tendency was observed, which closely correlated to the properties of the filtration-layer metal oxides (i.e. surface hydroxyl groups, hydrophilicity, surface charge, and adhesion energy for oil droplets). In consistent with the distinct bond strength of the surface hydroxyl groups, hydrophilicity of these common metal oxides are quite different. The differences in hydrophilicity consequently lead to different adhesion of these metal oxides towards oil droplets which consists very well with irreversible membrane fouling tendency. In addition, the surface charge of the metal oxide opposite to that of emulsion can help to alleviate irreversible membrane fouling in ultrafiltration. Highly hydrophilic Fe2O3 with lowest fouling tendency could be a potential filtration-layer material for the fabrication/modification of ceramic membranes for O/W emulsion treatment. To the best of our knowledge, this is the first study clearly showing the correlations between surface properties of filtration-layer metal oxides and ceramic membrane fouling tendency by O/W emulsion.

  2. Fabrication of nanopores in multi-layered silicon-based membranes using focused electron beam induced etching with XeF_2 gas

    International Nuclear Information System (INIS)

    Liebes-Peer, Yael; Bandalo, Vedran; Sökmen, Ünsal; Tornow, Marc; Ashkenasy, Nurit

    2016-01-01

    The emergent technology of using nanopores for stochastic sensing of biomolecules introduces a demand for the development of simple fabrication methodologies of nanopores in solid state membranes. This process becomes particularly challenging when membranes of composite layer architecture are involved. To overcome this challenge we have employed a focused electron beam induced chemical etching process. We present here the fabrication of nanopores in silicon-on-insulator based membranes in a single step process. In this process, chemical etching of the membrane materials by XeF_2 gas is locally accelerated by an electron beam, resulting in local etching, with a top membrane oxide layer preventing delocalized etching of the silicon underneath. Nanopores with a funnel or conical, 3-dimensional (3D) shape can be fabricated, depending on the duration of exposure to XeF_2, and their diameter is dominated by the time of exposure to the electron beam. The demonstrated ability to form high-aspect ratio nanopores in comparably thick, multi-layered silicon based membranes allows for an easy integration into current silicon process technology and hence is attractive for implementation in biosensing lab-on-chip fabrication technologies. (author)

  3. 3D morphological characterization of the polyamide active layer of RO and NF membranes using TEM and soft X-ray scattering

    Science.gov (United States)

    Culp, Tyler; Paul, Mou; Roy, Abhishek; Rosenberg, Steve; Behr, Michael; Kumar, Manish; Gomez, Enrique; Penn State Team; Dow Team

    Polyamide-based thin-film composite (TFC) membranes used for reverse osmosis (RO) and nanofiltration (NF) separation processes are at the forefront of water desalination and purification technologies due to their high salt rejection, high energy efficiency, and ease of operation. Nevertheless, in spite of the benefits of RO and NF membranes, many open questions about the internal nanostructure of the membrane active layer remain, such as the dispersion and distribution of acid functional groups. We demonstrate that resonant soft X-ray scattering (RSOXS), where the X-ray energy is tuned to absorption edges of the constituent materials, is a powerful tool to examine the microstructure of the polyamide layer. In conjunction with complementary techniques such as transmission electron microscopy (TEM), where tomography is used to obtain a 3D reconstruction of the polyamide active layer, the effect of cross-linking can be quantified in 3D for a systematic series of membranes. This relationship can then be applied to a series of commercially available RO and NF membranes where the effect of polyamide cross-linking on their respective structure and water transport properties can be evaluated. The combination of RSOXS with traditional characterization tools provides a strategy for linking the chemical structure to the morphology and water transport properties of RO and NF membranes.

  4. An acoustic metamaterial composed of multi-layer membrane-coated perforated plates for low-frequency sound insulation

    Science.gov (United States)

    Fan, Li; Chen, Zhe; Zhang, Shu-yi; Ding, Jin; Li, Xiao-juan; Zhang, Hui

    2015-04-01

    Insulating against low-frequency sound (below 500 Hz ) remains challenging despite the progress that has been achieved in sound insulation and absorption. In this work, an acoustic metamaterial based on membrane-coated perforated plates is presented for achieving sound insulation in a low-frequency range, even covering the lower audio frequency limit, 20 Hz . Theoretical analysis and finite element simulations demonstrate that this metamaterial can effectively block acoustic waves over a wide low-frequency band regardless of incident angles. Two mechanisms, non-resonance and monopolar resonance, operate in the metamaterial, resulting in a more powerful sound insulation ability than that achieved using periodically arranged multi-layer solid plates.

  5. SIMULATION OF POROSITY AND PTFE CONTENT IN GAS DIFFUSION LAYER ON PROTON EXCHANGE MEMBRANE FUEL CELL PERFORMANCE

    Directory of Open Access Journals (Sweden)

    NUR H. MASLAN

    2016-01-01

    Full Text Available Numerous research and development activities have been conducted to optimize the operating parameters of a proton exchange membrane fuel cell (PEMFC by experiments and simulations. This study explains the development of a 3D model by using ANSYS FLUENT 14.5 to determine the optimum PEMFC parameters, namely, porosity and polytetrafluoroethylene (PTFE content, in the gas diffusion layer (GDL. A 3D model was developed to analyze the properties and effects of GDL. Simulation results showed that the increase in GDL porosity significantly improved the performance of PEMFC in generating electrical power. However, the performance of PEMFC decreased with increasing PTFE content in GDL. Thus, the PTFE content in the GDL must be optimized and the optimum PTFE content should be 5 wt%. The model developed in this simulation showed good capability in simulating the PEMFC parameters to assist the development process of PEMFC design.

  6. High voltage photo-switch package module having encapsulation with profiled metallized concavities

    Science.gov (United States)

    Sullivan, James S; Sanders, David M; Hawkins, Steven A; Sampayan, Stephen A

    2015-05-05

    A photo-conductive switch package module having a photo-conductive substrate or wafer with opposing electrode-interface surfaces metalized with first metallic layers formed thereon, and encapsulated with a dielectric encapsulation material such as for example epoxy. The first metallic layers are exposed through the encapsulation via encapsulation concavities which have a known contour profile, such as a Rogowski edge profile. Second metallic layers are then formed to line the concavities and come in contact with the first metal layer, to form profiled and metalized encapsulation concavities which mitigate enhancement points at the edges of electrodes matingly seated in the concavities. One or more optical waveguides may also be bonded to the substrate for coupling light into the photo-conductive wafer, with the encapsulation also encapsulating the waveguides.

  7. Impact of a silver layer on the membrane of tap water filters on the microbiological quality of filtered water

    Directory of Open Access Journals (Sweden)

    Bruderek Juliane

    2008-10-01

    Full Text Available Abstract Background Bacteria in the hospital's drinking water system represent a risk for the acquisition of a nosocomial infection in the severely immunocompromised host. Terminal tap water filters may be used to prevent nosocomial Legionnaires' disease. We present data from water samples using an improved kind of tap water filters. Methods In a blinded study on an intermediate care unit of the thoracic surgery department, a modified type of the Germlyser water filter (Aqua-Free Membrane Technology with a newly-introduced silver layer on the filtration membrane was compared to its preceding type without such a layer on 15 water outlets. We determined growth of Legionella, other pathogenic bacteria, and the total heterotrophic plate count in unfiltered water and filtered water samples after filter usage intervals of 1 through 4 weeks. Results A total of 299 water samples were tested. Twenty-nine of the 60 unfiltered water samples contained Legionella of various serogroups (baseline value. In contrast, all samples filtered by the original water filter and all but one of the water samples filtered by the modified filter type remained Legionella-free. No other pathogenic bacteria were detected in any filtered sample. The total plate count in water samples increased during use of both kinds of filters over time. However, for the first 7 days of use, there were significantly fewer water samples containing >100 CFU per mL when using the new filter device compared with the older filters or taps with no filter. No advantage was seen thereafter. Conclusion The use of this type of terminal water filter is an appropriate method to protect immunocompromised patients from water-borne pathogens such as Legionella.

  8. Assessment of heavy metals contamination in surface layers of Roztocze National Park forest soils (SE Poland) by indices of pollution.

    Science.gov (United States)

    Mazurek, Ryszard; Kowalska, Joanna; Gąsiorek, Michał; Zadrożny, Paweł; Józefowska, Agnieszka; Zaleski, Tomasz; Kępka, Wojciech; Tymczuk, Maryla; Orłowska, Kalina

    2017-02-01

    In most cases, in soils exposed to heavy metals accumulation, the highest content of heavy metals was noted in the surface layers of the soil profile. Accumulation of heavy metals may occur both as a result of natural processes as well as anthropogenic activities. The quality of the soil exposed to heavy metal contamination can be evaluated by indices of pollution. On the basis of determined heavy metals (Pb, Zn, Cu, Mn, Ni and Cr) in the soils of Roztocze National Park the following indices of pollution were calculated: Enrichment Factor (EF), Geoaccumulation Index (I geo ), Nemerow Pollution Index (PI Nemerow ) and Potential Ecological Risk (RI). Additionally, we introduced and calculated the Biogeochemical Index (BGI), which supports determination of the ability of the organic horizon to accumulate heavy metals. A tens of times higher content of Pb, Zn, Cu and Mn was found in the surface layers compared to their content in the parent material. This distribution of heavy metals in the studied soils was related to the influence of anthropogenic pollution (both local and distant sources of emission), as well as soil properties such as pH, organic carbon and total nitrogen content. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Incorporating Embedded Microporous Layers into Topologically Equivalent Pore Network Models for Oxygen Diffusivity Calculations in Polymer Electrolyte Membrane Fuel Cell Gas Diffusion Layers

    International Nuclear Information System (INIS)

    Fazeli, Mohammadreza; Hinebaugh, James; Bazylak, Aimy

    2016-01-01

    Highlights: • Pore network model for modeling PEMFC MPL-coated GDL effective diffusivity. • Bilayered GDL (substrate and MPL) is modeled with a hybrid network of block MPL elements combined with discrete substrate pores. • Diffusivities of MPL-coated GDLs agree with analytical solutions. - Abstract: In this work, a voxel-based methodology is introduced for the hybridization of a pore network with interspersed nano-porous material elements allowing pore network based oxygen diffusivity calculations in a 3D image of a polymer electrolyte membrane (PEM) fuel cell gas diffusion layer (GDL) with an embedded microporous layer (MPL). The composite GDL is modeled by combining a hybrid network of block MPL elements with prescribed bulk material properties and a topologically equivalent network of larger discrete pores and throats that are directly derived from the 3D image of the GDL substrate. This hybrid network was incorporated into a pore network model, and effective diffusivity predictions of GDL materials with MPL coatings were obtained. Stochastically generated numerical models of carbon paper substrates with and without MPLs were used, and the pore space was directly extracted from this realistic geometry as the input for the pore network model. The effective diffusion coefficient of MPL-coated GDL materials was predicted from 3D images in a pore network modeling environment without resolving the nano-scale structure of the MPL. This method is particularly useful due to the disparate length scales that are involved when attempting to capture pore-scale transport in the GDL. Validation was performed by comparing our predicted diffusivity values to analytical predictions, and excellent agreement was observed. Upon conducting a mesh sensitivity study, it was determined that an MPL element size of 7 μm provided sufficiently high resolution for accurately describing the MPL nano-structure.

  10. Thickness of the Macula, Retinal Nerve Fiber Layer, and Ganglion Cell Layer in the Epiretinal Membrane: The Repeatability Study of Optical Coherence Tomography.

    Science.gov (United States)

    Lee, Haeng-Jin; Kim, Min-Su; Jo, Young-Joon; Kim, Jung-Yeul

    2015-07-01

    To analyze the repeatability of measurements of the thicknesses of the macula, retinal nerve fiber layer (RNFL), and ganglion cell inner plexiform layer (GCIPL) using spectral-domain optical coherence tomography (SD-OCT) in the epiretinal membrane (ERM). The prospective study analyzed patients who visited our retinal clinic from June 2013 to January 2014. An experienced examiner measured the thicknesses twice using macular cube 512 × 128 and optic disc cube 200 × 200 scans. The repeatability of the thicknesses of the macula, RNFL, and GCIPL were compared using the intraclass correlation coefficient (ICC) of two groups based on the central macular thickness (group A, ≤ 450 μm; group B, > 450 μm). A total of 88 patients were analyzed. The average thicknesses of the central macula, RNFL, and GCIPL were 256.5, 96.6, and 84.4 μm, respectively, in the normal fellow eye and 412.3, 94.6, and 56.7 μm in the affected eye. The ICCs of the central macula, RNFL, and GCIPL were 0.995, 0.994, and 0.996, respectively, for the normal fellow eye and 0.991, 0.973, and 0.881 for the affected eye. The average thicknesses of the central macula, RNFL, and GCIPL in group A were 360.9, 93.5, and 63.4 μm, respectively, and the ICCs were 0.997, 0.987, and 0.995. The thicknesses in group B were 489.5, 96.2, and 46.6 μm, respectively, and the ICCs were 0.910, 0.942, and 0.603, significantly lower repeatability compared with group A (P macula.

  11. Encapsulation of high temperature molten salts

    Science.gov (United States)

    Oxley, James D.; Mathur, Anoop Kumar

    2017-05-16

    The present disclosure relates to a method of encapsulating microcapsules containing relatively high temperature phase change materials and the microcapsules so produced. The microcapsules are coated with an inorganic binder, film former and an inorganic filler. The microcapsules may include a sacrificial layer that is disposed between the particle and the coating. The microcapsules may also include an inner coating layer, sacrificial layer and outer coating layer. The microcapsules are particularly useful for thermal energy storage in connection with, e.g., heat collected from concentrating solar collectors.

  12. Fabrication of gas diffusion layer based on x-y robotic spraying technique for proton exchange membrane fuel cell application

    International Nuclear Information System (INIS)

    Sitanggang, Ramli; Mohamad, Abu Bakar; Daud, Wan Ramli Wan; Kadhum, Abdul Amir H.; Iyuke, S.E.

    2009-01-01

    The x-y robotic spraying technique developed in the Universiti Kebangsaan Malaysia is capable of fabricating various sizes of thickness and porosity of gas diffusion layer (GDL) used in the proton exchange membrane fuel cell (PEMFC). These parameters are obtained by varying the characteristic spray numbers of the robotic spraying machine. This investigation results were adequately represented with mathematical equations for hydrogen gas distribution in GDL. Volumetric modulus (M) parameter is used to determine the value of current density produced on the electrode of a single cell PEMFC. Thus the M parameter can be employed as indicator for a successful GDL fabrication. GDL type 4 has three variables of layer design that can be optimized to function as gas distributor, gas storage, flooding preventer on GDL surface, to evacuate water from the electrode and to control the electrical conductivity. The gas distribution in GDL was mathematically represented with average error of 15.5%. The M value of GDL type 4 according to the model was 0.22 cm 3 /s and yielded a current density of 750 A/m 2 .

  13. Análises do comportamento físico de um solo contaminado por borra oleosa ácida e encapsulado com cimento Portland Analyses of physical behavior of a soil contaminated by acidic oily sludge and encapsulated with cement Portland

    Directory of Open Access Journals (Sweden)

    José Waldomiro Jiménez Rojas

    2008-06-01

    Full Text Available Este trabalho tem como objetivo aplicar a técnica de encapsulamento em um solo contaminado com crescentes quantidades do resíduo industrial borra oleosa ácida, utilizando como agente encapsulante o cimento Portland CP-V ARI. A aplicação da técnica de encapsulamento consistiu na realização de estudos pós-tratamento, analisando fisicamente o solo contaminado através de ensaios de resistência à compressão simples e durabilidade. Os resultados apontam que quanto maior a quantidade de borra oleosa ácida presente no solo encapsulado, menor a resistência à compressão simples e maior a perda de massa.The objective of this study is applying the encapsulation technique in soil contaminated with increasing amounts of acidic oily sludge industrial residues, using Portland cement CP-V ARI as the encapsulating agent. The application of the encapsulation technique consisted in the accomplishment of post-treatment studies, analyzing the contaminated soil physically through unconfined compressive strength and durability tests. The results showed that an increasing amount of acidic oily sludge in the encapsulated soil ends up lowering the unconfined compressive strength as well as increasing the mass loss.

  14. Chromium in soil layers and plants on closed landfill site after landfill leachate application.

    Science.gov (United States)

    Zupancic, Marija; Justin, Maja Zupancic; Bukovec, Peter; Selih, Vid Simon

    2009-06-01

    Landfill leachate (LL) usually contains low concentrations of heavy metals due to the anaerobic conditions in the methanogenic landfill body after degradation of easily degradable organic matter and the neutral pH of LL, which prevents mobilization and leaching of metals. Low average concentrations of metals were also confirmed in our extensive study on the rehabilitation of an old landfill site with vegetative landfill cover and LL recirculation after its treatment in constructed wetland. The only exception was chromium (Cr). Its concentrations in LL ranged between 0.10 and 2.75 mg/L, and were higher than the concentrations usually found in the literature. The objectives of the study were: (1) to understand why Cr is high in LL and (2) to understand the fate and transport of Cr in soil and vegetation of landfill cover due to known Cr toxicity to plants. The total concentration of Cr in LL, total and exchangeable concentrations of Cr in landfill soil cover and Cr content in the plant material were extensively monitored from May 2004 to September 2006. By obtained data on Cr concentration in different landfill constituents, supported with the data on the amount of loaded leachate, amount of precipitation and potential evapotranspiration (ETP) during the performance of the research, a detailed picture of time distribution and co-dependency of Cr is provided in this research. A highly positive correlation was found between concentrations of Cr and dissolved organic carbon (r=0.875) in LL, which indicates the co-transport of Cr and dissolved organic carbon through the system. Monitoring results showed that the substrate used in the experiment did not contribute to Cr accumulation in the landfill soil cover, resulting in percolation of a high proportion of Cr back into the waste layers and its circulation in the system. No negative effects on plant growth appeared during the monitoring period. Due to low uptake of Cr by plants (0.10-0.15 mg/kg in leaves and 0.05-0.07 mg

  15. Production and Characterization of a Novel, Electrospun, Tri-Layer Polycaprolactone Membrane for the Segregated Co-Culture of Bone and Soft Tissue

    Directory of Open Access Journals (Sweden)

    Sasima Puwanun

    2016-06-01

    Full Text Available Composite tissue-engineered constructs combining bone and soft tissue have applications in regenerative medicine, particularly dentistry. This study generated a tri-layer, electrospun, poly-ε-caprolactone membrane, with two microfiber layers separated by a layer of nanofibers, for the spatially segregated culture of mesenchymal progenitor cells (MPCs and fibroblasts. The two cell types were seeded on either side, and cell proliferation and spatial organization were investigated over several weeks. Calcium deposition by MPCs was detected using xylenol orange (XO and the separation between fibroblasts and the calcified matrix was visualized by confocal laser scanning microscopy. SEM confirmed that the scaffold consisted of two layers of micron-diameter fibers with a thin layer of nano-diameter fibers in-between. Complete separation of cell types was maintained and calcified matrix was observed on only one side of the membrane. This novel tri-layer membrane is capable of supporting the formation of a bilayer of calcified and non-calcified connective tissue.

  16. Encapsulation with structured triglycerides

    Science.gov (United States)

    Lipids provide excellent materials to encapsulate bioactive compounds for food and pharmaceutical applications. Lipids are renewable, biodegradable, and easily modified to provide additional chemical functionality. The use of structured lipids that have been modified with photoactive properties are ...

  17. STRESS-STRAIN STATE OF ROCKFILL DAM DOUBLE-LAYER FACE MADE OF REINFORCED CONCRETE AND SOIL-CEMENT CONCRETE

    Directory of Open Access Journals (Sweden)

    Sainov Mikhail Petrovich

    2017-05-01

    Full Text Available There was studied the stress-strain state of 215 m high rockfill dam where the seepage-control element is presented by a reinforced concrete face of soil-cement concrete placed on the under-face zone. Calculations were carried out for two possible variants of deformability of rock outline taking into account the non-linearity of its deformative properties. It was obtained that the reinforced concrete face and the soil-cement concrete under-face zone work jointly as a single construction - a double-layer face. As the face assembly resting on rock is made with a sliding joint the scheme of its static operation is similar to the that of the beam operation on the elastic foundation. At that, the upstream surface of the double-layer face is in the compressed zone and lower one is in the tensile zone. This protects the face against cracking on the upstream surface but threatens with structural failure of soil-cement concrete. In order to avoid appearance of cracks in soil-cement concrete part due to tension it is necessary to achieve proper compaction of rockfill and arrange transverse joints in the double-layer face.

  18. Determination of the free ion concentration of trace metals in soil solution using a soil column Donnan membrane technique

    NARCIS (Netherlands)

    Weng, L.; Temminghoff, E.J.M.; Riemsdijk, van W.H.

    2001-01-01

    Accurate measurement of the free metal ion is difficult, especially for trace metals present in very small concentrations (less than micromolar) in natural systems. The recently developed Donnan membrane technique can measure the concentrations in solution in the presence of inorganic and organic

  19. Green living roof implementation and influences of the soil layer on its properties

    Directory of Open Access Journals (Sweden)

    Dimitrijević Dragana G.

    2016-01-01

    Full Text Available Affected by undeniable climatic change, the temperature of the urban areas rises continually, increasing rapidly the energy problem of cities and amplifying the pollution problems. The thermal stress is increased, thus both the indoor and the outdoor thermal comfort levels are decreased, enhancing the health problems. Green roof implementation in the building envelope is strategy that provides heat island amelioration, thermal comfort for occupants and reduces energy consumption of buildings. Green living roofs are a passive cooling technique, which can stop the incoming solar radiation from reaching the building structure below. In this paper, we assessed the importance of the green roofs in providing environmental and building energy benefits, and brief investigation on the different configuration of the soil layer in the green roof assembly influences to the temperature of the roof surface was presented. Investigation was conducted for first phase of the living roof growth. Four cells were designed in SolidWorks software where the transient thermal study was performed in order to determine differences between the behavior of the conventional roof and three green roof types.

  20. Divergent Responses of Forest Soil Microbial Communities under Elevated CO2 in Different Depths of Upper Soil Layers.

    Science.gov (United States)

    Yu, Hao; He, Zhili; Wang, Aijie; Xie, Jianping; Wu, Liyou; Van Nostrand, Joy D; Jin, Decai; Shao, Zhimin; Schadt, Christopher W; Zhou, Jizhong; Deng, Ye

    2018-01-01

    Numerous studies have shown that the continuous increase of atmosphere CO 2 concentrations may have profound effects on the forest ecosystem and its functions. However, little is known about the response of belowground soil microbial communities under elevated atmospheric CO 2 (eCO 2 ) at different soil depth profiles in forest ecosystems. Here, we examined soil microbial communities at two soil depths (0 to 5 cm and 5 to 15 cm) after a 10-year eCO 2 exposure using a high-throughput functional gene microarray (GeoChip). The results showed that eCO 2 significantly shifted the compositions, including phylogenetic and functional gene structures, of soil microbial communities at both soil depths. Key functional genes, including those involved in carbon degradation and fixation, methane metabolism, denitrification, ammonification, and nitrogen fixation, were stimulated under eCO 2 at both soil depths, although the stimulation effect of eCO 2 on these functional markers was greater at the soil depth of 0 to 5 cm than of 5 to 15 cm. Moreover, a canonical correspondence analysis suggested that NO 3 -N, total nitrogen (TN), total carbon (TC), and leaf litter were significantly correlated with the composition of the whole microbial community. This study revealed a positive feedback of eCO 2 in forest soil microbial communities, which may provide new insight for a further understanding of forest ecosystem responses to global CO 2 increases. IMPORTANCE The concentration of atmospheric carbon dioxide (CO 2 ) has continuously been increasing since the industrial revolution. Understanding the response of soil microbial communities to elevated atmospheric CO 2 (eCO 2 ) is important for predicting the contribution of the forest ecosystem to global atmospheric change. This study analyzed the effect of eCO 2 on microbial communities at two soil depths (0 to 5 cm and 5 to 15 cm) in a forest ecosystem. Our findings suggest that the compositional and functional structures of microbial

  1. Application of a mixture of soils to create a stable layer of support on the slope in ponds waterproofed with geo membranes. Application to a specific case in the reservoir Conseller Jose Ramon Garcia Anton in Elche (Alicante); Aplicacion de una mezcla de suelos para el desarrollo de la capa de apoyo estable a lo largo del tiempo en los taludes para la geomembrana de la balsa Conseller Jose Ramon Garcia Anton en Elche. Alicante

    Energy Technology Data Exchange (ETDEWEB)

    Ferran Gozalvez, F. J.; Ferrer Gisbert, C.; Redon Santafe, M.; Perez Sanchez, M.; Torregrosa Solar, J. S.; Zapata Raboso, F. J.; Sanchez Romero, F. J.

    2014-02-01

    This text present the experience developed in a reservoir in Elche (Alicante). This communication explains the importance of the layer of support to prevent the punching. This phenomenon can occur in a reservoir that has a deficient layer of support. Also, the paper describes the requirements to be met by the support layer to perform its function. (Author)

  2. Spatial variability of steady-state infiltration into a two-layer soil system on burned hillslopes

    Science.gov (United States)

    Kinner, D.A.; Moody, J.A.

    2010-01-01

    Rainfall-runoff simulations were conducted to estimate the characteristics of the steady-state infiltration rate into 1-m2 north- and south-facing hillslope plots burned by a wildfire in October 2003. Soil profiles in the plots consisted of a two-layer system composed of an ash on top of sandy mineral soil. Multiple rainfall rates (18.4-51.2 mm h-1) were used during 14 short-duration (30 min) and 2 long-duration simulations (2-4 h). Steady state was reached in 7-26 min. Observed spatially-averaged steady-state infiltration rates ranged from 18.2 to 23.8 mm h-1 for north-facing and from 17.9 to 36.0 mm h-1 for south-facing plots. Three different theoretical spatial distribution models of steady-state infiltration rate were fit to the measurements of rainfall rate and steady-state discharge to provided estimates of the spatial average (19.2-22.2 mm h-1) and the coefficient of variation (0.11-0.40) of infiltration rates, overland flow contributing area (74-90% of the plot area), and infiltration threshold (19.0-26 mm h-1). Tensiometer measurements indicated a downward moving pressure wave and suggest that infiltration-excess overland flow is the runoff process on these burned hillslope with a two-layer system. Moreover, the results indicate that the ash layer is wettable, may restrict water flow into the underlying layer, and increase the infiltration threshold; whereas, the underlying mineral soil, though coarser, limits the infiltration rate. These results of the spatial variability of steady-state infiltration can be used to develop physically-based rainfall-runoff models for burned areas with a two-layer soil system. ?? 2010 Elsevier B.V.

  3. Pore-Size-Tuned Graphene Oxide Frameworks as Ion-Selective and Protective Layers on Hydrocarbon Membranes for Vanadium Redox-Flow Batteries.

    Science.gov (United States)

    Kim, Soohyun; Choi, Junghoon; Choi, Chanyong; Heo, Jiyun; Kim, Dae Woo; Lee, Jang Yong; Hong, Young Taik; Jung, Hee-Tae; Kim, Hee-Tak

    2018-05-07

    The laminated structure of graphene oxide (GO) membranes provides exceptional ion-separation properties due to the regular interlayer spacing ( d) between laminate layers. However, a larger effective pore size of the laminate immersed in water (∼11.1 Å) than the hydrated diameter of vanadium ions (>6.0 Å) prevents its use in vanadium redox-flow batteries (VRFB). In this work, we report an ion-selective graphene oxide framework (GOF) with a d tuned by cross-linking the GO nanosheets. Its effective pore size (∼5.9 Å) excludes vanadium ions by size but allows proton conduction. The GOF membrane is employed as a protective layer to address the poor chemical stability of sulfonated poly(arylene ether sulfone) (SPAES) membranes against VO 2 + in VRFB. By effectively blocking vanadium ions, the GOF/SPAES membrane exhibits vanadium-ion permeability 4.2 times lower and a durability 5 times longer than that of the pristine SPAES membrane. Moreover, the VRFB with the GOF/SPAES membrane achieves an energy efficiency of 89% at 80 mA cm -2 and a capacity retention of 88% even after 400 cycles, far exceeding results for Nafion 115 and demonstrating its practical applicability for VRFB.

  4. Encapsulating peritonitis: computed tomography and surgical correlation

    Energy Technology Data Exchange (ETDEWEB)

    Kadow, Juliana Santos; Fingerhut, Carla Jeronimo Peres; Fernandes, Vinicius de Barros; Coradazzi, Klaus Rizk Stuhr; Silva, Lucas Marciel Soares; Penachim, Thiago Jose, E-mail: vinicius.barros.fernandes@gmail.com [Pontificia Universidade Catolica de Campinas (PUC-Campinas), Campinas, SP (Brazil). Hospital e Maternidade Celso Pierro

    2014-07-15

    Sclerosing encapsulating peritonitis is a rare and frequently severe entity characterized by total or partial involvement of small bowel loops by a membrane of fibrous tissue. The disease presents with nonspecific clinical features of intestinal obstruction, requiring precise imaging diagnosis to guide the treatment. The present report emphasizes the importance of computed tomography in the diagnosis of this condition and its confirmation by surgical correlation. (author)

  5. A new method of fully three dimensional analysis of stress field in the soil layer of a soil-mantled hillslope

    Science.gov (United States)

    Wu, Y. H.; Nakakita, E.

    2017-12-01

    Hillslope stability is highly related to stress equilibrium near the top surface of soil-mantled hillslopes. Stress field in a hillslope can also be significantly altered by variable groundwater motion under the rainfall influence as well as by different vegetation above and below the slope. The topographic irregularity, biological effects from vegetation and variable rainfall patterns couple with others to make the prediction of shallow landslide complicated and difficult. In an increasing tendency of extreme rainfall, the mountainous area in Japan has suffered more and more shallow landslides. To better assess shallow landslide hazards, we would like to develop a new mechanically-based method to estimate the fully three-dimensional stress field in hillslopes. The surface soil-layer of hillslope is modelled as a poroelastic medium, and the tree surcharge on the slope surface is considered as a boundary input of stress forcing. The modelling of groundwater motion is involved to alter effective stress state in the soil layer, and the tree root-reinforcement estimated by allometric equations is taken into account for influencing the soil strength. The Mohr-Coulomb failure theory is then used for locating possible yielding surfaces, or says for identifying failure zones. This model is implemented by using the finite element method. Finally, we performed a case study of the real event of massive shallow landslides occurred in Hiroshima in August, 2014. The result shows good agreement with the field condition.

  6. Ultrasonographic findings of sclerosing encapsulating peritonitis

    Energy Technology Data Exchange (ETDEWEB)

    Han, Jong Kyu; Lee, Hae Kyung; Moon, Chul; Hong, Hyun Sook; Kwon, Kwi Hyang; Choi, Deuk Lin [Soonchunhyangi University College of Medicine, Seoul (Korea, Republic of)

    2001-03-15

    To evaluate the ultrasonographic findings of the patients with sclerosing encapsulating peritonitis (SEP). Thirteen patients with surgically confirmed sclerosing encapsulating peritonitis were involved in this study. Because of intestinal obstruction, all patients had received operations. Among 13 patients, 12 cases had continuous ambulatory peritoneal dialysis (CAPD) for 2 months-12 years and 4 months from (mean; 6 years and 10 months), owing to chronic renal failure and one patient had an operation due to variceal bleeding caused by liver cirrhosis. On ultrasonographic examination, all patients showed loculated ascites which were large (n=7) or small (n=6) in amount with multiple separations. The small bowel loops were tethered posteriorly perisaltic movement and covered with the thick membrane. The ultrasonographic of findings of sclerosing encapsulating peritonitis were posteriorly tethered small bowels covered with a thick membrane and loculated ascites with multiple septa. Ultrasonographic examination can detect the thin membrane covering the small bowel loops in the early phase of the disease, therefore ultrasonography would be a helpful modality to diagnose SEP early.

  7. Experimental study on the self-humidification effect in proton exchange membrane fuel cells containing double gas diffusion backing layer

    International Nuclear Information System (INIS)

    Kong, Im Mo; Choi, Jong Won; Kim, Sung Il; Lee, Eun Sook; Kim, Min Soo

    2015-01-01

    Highlights: • Investigated self-humidification effect of structurally modified GDBLs in PEMFCs. • One conventional and two modified GDLs were prepared. • Structural design of the GDBLs significantly affected self-humidification. • Stacking was found to have negligible effect on self-humidification. • It can be applied readily to self-humidified PEMFCs. - Abstract: Adequate hydration of the membrane is required to ensure high proton conductivity in proton exchange membrane fuel cells (PEMFCs), which, in turn, is required for achieving high cell performances. While external humidifiers are typically used to humidify the supplied air in conventional systems, their use increases the complexity, weight, volume, and parasitic power loss in fuel cell systems, rendering them unviable in some systems, particularly for portable applications. In this study, the structure of a gas diffusion backing layer (GDBL) was modified to enhance the self-humidification effect in PEMFCs. Three types of GDLs were prepared for the experiments: a conventional GDL (GDL-A with uniform single GDBL) and two modified GDLs (GDL-A′B with uniform double GDBL and GDL-A′C with heterogeneous double GDBLs). In order to evaluate the effect of stacking and structural design on the self-humidification characteristics, some characteristics of the GDLs such as contact angle, resistance, and vapor permeation rate were measured. The electrochemical performances of the fuel cells were also measured at various relative humidity (RH) and stoichiometric ratio (SR) conditions. The results showed that stacking had a negligible effect, whereas the structural design of the GDBL had a significant effect on self-humidification. The self-humidification effect and the cell performance were improved significantly in the structurally modified GDBL. In addition, considering the actual field conditions and the results of the present study, it was concluded that the structural modifications made to the GDBL would

  8. Seismic behavior of NPP structures subjected to realistic 3D, inclined seismic motions, in variable layered soil/rock, on surface or embedded foundations

    International Nuclear Information System (INIS)

    Jeremić, B.; Tafazzoli, N.; Ancheta, T.; Orbović, N.; Blahoianu, A.

    2013-01-01

    Highlights: • Full 3D, inclined, incoherent seismic motions used for modeling SSI of an NPP. • Analyzed effects of variable and uniform soil/rock layering profiles on SSI. • Surface and embedded foundations were modeled and differences analyzed. - Abstract: Presented here is an investigation of the seismic response of a massive NPP structures due to full 3D, inclined, un-correlated input motions for different soil and rock profiles. Of particular interest are the effects of soil and rock layering on the response and the changes of input motions (frequency characteristics) due to such layering. In addition to rock/soil layering effects, investigated are also effects of foundation embedment on dynamic response. Significant differences were observed in dynamic response of containment and internal structure founded on surface and on embedded foundations. These differences were observed for both rock and soil profiles. Select results are used to present most interesting findings

  9. Characterization of internal wetting in polymer electrolyte membrane gas diffusion layers

    Science.gov (United States)

    Cheung, Perry; Fairweather, Joseph D.; Schwartz, Daniel T.

    Capillary pressure vs. saturation (P C(S L)) curves are fundamental to understanding liquid water transport and flooding in PEM gas diffusion layers (GDLs). P C(S L) curves convolute the influence of GDL pore geometry and internal contact angles at the three-phase liquid/solid/gas boundary. Even simple GDL materials are a spatially non-uniform mixture of carbon fiber and binder, making a Gaussian distribution of contact angles likely, based on the Cassie-Baxter equation. For a given Gaussian contact angle distribution with mean (θ Mean) and standard deviation (σ), a realistic P C(S L) curve can be computed using a bundle of capillaries model and GDL pore size distribution data. As expected, computed P C(S L) curves show that θ Mean sets the overall hydrophilic (θ Mean 90°) character of the GDL (i.e., liquid saturation level at a given capillary pressure), and σ affects the slope of the P C(S L) curve. The capillary bundle model also can be used with (θ Mean, σ) as unknown parameters that are best-fit to experimentally acquired P C(S L) and pore size distribution data to find (θ Mean, σ) values for actual GDL materials. To test this, pore size distribution data was acquired for Toray TGP-H-090 along with hysteretic liquid and gas intrusion capillary pressure curve data. High quality best-fits were found between the model and combined datasets, with GDL liquid intrusion showing fairly neutral internal surface wetting properties (θ Mean = 92° and σ = 10°) whereas gas intrusion displayed a hydrophilic character (θ Mean = 52° and σ = 8°). External liquid advancing and receding contact angles were also measured on this same material and they also showed major hysteresis. The new methods described here open the door for better understanding of the link between GDL material processing and the wetting properties that affect flooding.

  10. Soil Physical Constraints on Intrinsic Biodegradation of Petroleum Vapors in a Layered Subsurface

    DEFF Research Database (Denmark)

    Kristensen, Andreas Houlberg; Henriksen, Kaj; Mortensen, Lars

    2010-01-01

    Intrinsic biodegradation of organic contaminants in the soil vadose zone depends on site-specific soil properties controlling biophysical and geochemical interactions within the soil pore space. In this study we evaluated the effect of soil texture and moisture conditions on aerobic biodegradatio...... in the deep vadose zone. As a result, management of petroleum hydrocarbon spill sites will benefit from site-specific conceptual models in which the vadose zone is divided into geological compartments with different biophysical potential for biodegradation and bioremediation....

  11. In situ nuclear magnetic resonance response of permafrost and active layer soil in boreal and tundra ecosystems

    Directory of Open Access Journals (Sweden)

    M. A. Kass

    2017-12-01

    Full Text Available Characterization of permafrost, particularly warm and near-surface permafrost which can contain significant liquid water, is critical to understanding complex interrelationships with climate change, ecosystems, and disturbances such as wildfires. Understanding the vulnerability and resilience of permafrost requires an interdisciplinary approach, relying on (for example geophysical investigations, ecological characterization, direct observations, remote sensing, and more. As part of a multiyear investigation into the impacts of wildfires on permafrost, we have collected in situ measurements of the nuclear magnetic resonance (NMR response of the active layer and permafrost in a variety of soil conditions, types, and saturations. In this paper, we summarize the NMR data and present quantitative relationships between active layer and permafrost liquid water content and pore sizes and show the efficacy of borehole NMR (bNMR to permafrost studies. Through statistical analyses and synthetic freezing simulations, we also demonstrate that borehole NMR is sensitive to the nucleation of ice within soil pore spaces.

  12. On-line cake-layer management by trans-membrane pressure steady state assessment in Anaerobic Membrane Bioreactors for wastewater treatment

    NARCIS (Netherlands)

    Jeison, D.; Lier, van J.B.

    2006-01-01

    Membrane bioreactors have been increasingly applied for wastewater treatment during the last two decades. High energy requirements and membrane capital costs remains as their main drawback. A new strategy of operation is presented based on a continuous critical flux determination, preventing

  13. Plantlets from encapsulated shoot buds of Catalpa ovata G. Don

    Directory of Open Access Journals (Sweden)

    Halina Wysokińska

    2014-01-01

    Full Text Available Shoot buds isolated from in vitro shoot cultures of Catalpa ovata G. Don were encapsulated using 3% sodium alginate with sucrose (3% and 50 mM calcium chloride. The morphogenic response of encapsulated buds was affected by such factors, like composition of the media and the presence of growth regulators. The highest frequency of plantlet germination from encapsulated buds (70% within 4 weeks was obtained on Woody Plant medium (WP (Lloyd and McCown 1980 containing indole-3-butyric acid (IBA (1 mg/l. The process was substantially inhibited by cold-storage (4oC of encapsulated buds. In this case, the frequency response ranged from 3% to 22% dependent on storage period (28 or 42 days and the presence of the paraffin coat covering the alginate capsules. The plantlets developed from both unstored and stored encapsulated buds of C. ovata were transplanted to soil and grew in pots to phenotypically normal plants.

  14. The characterization of petroleum and creosote-contaminated soils: Class component analysis by thin layer chromatography with flame ionization detection

    International Nuclear Information System (INIS)

    Pollard, S.J.T.; Hrudey, S.E.; Fuhr, B.J.; Alex, R.F.; Holloway, L.R.

    1992-01-01

    The assessment and reclamation of coal tar, creosote and petroleum-contaminated sites is emerging as a major challenge to industry and the federal and provincial Canadian governments. Contaminants frequently include polynuclear aromatic compounds (PAH), several high molecular weight analogues of which are documented carcinogens. Adaptation of thin layer chromatography with flame ionization detection for the analysis of hydrocarbon-contaminated soils is described. The method is directly applicable to the analysis of oily waste extracts from petroleum and creosote wood preservative site soils and is capable of distinguishing between the saturate, aromatic and polar components of waste residues. The method provides a rapid, low cost class component analysis of heavy hydrocarbon waste extracts and is particularly useful for estimating the extent of weathering experienced by chronically exposed hydrocarbon wastes in the soil environment. As such, it is useful as a screening tool for a preliminary assessment of the biotreatability or inherent recalcitrance of hydrocarbon waste mixtures. 11 refs., 5 figs

  15. Effect of Hydrograph Separation on Suspended Sediment Concentration Predictions in a Forested Headwater with Thick Soil and Weathered Gneiss Layers

    Directory of Open Access Journals (Sweden)

    Naoki Kabeya

    2014-06-01

    Full Text Available Two-component hydrograph separation using oxygen-18 concentrations was conducted at a sediment runoff observation weir installed in a small subcatchment of a forested gneiss catchment in Japan. The mean soil thickness of this catchment is 7.27 m, which comprises 3.29 m of brown forest soil (A and B layers and a 3.98-m layer of heavily weathered gneiss. Data were collected for a storm on 20–21 May 2003, and the percentage of event water separated by the stable isotope ratio in comparison with the total rainfall amount was about 1%. This value is within the ratio of a riparian zone in a drainage area. Temporal variation of suspended sediment concentration exhibited higher correlation with the event water component than with the total runoff or pre-event water component. This shows that the riparian zone causes rainwater to flow out quickly during a rain event, and that this is an important area of sediment production and transportation in a forested headwater with thick soil and weathered gneiss layers.

  16. Treatment of turtle aquaculture effluent by an improved multi-soil-layer system.

    Science.gov (United States)

    Song, Ying; Huang, Yu-ting; Ji, Hong-fang; Nie, Xin-jun; Zhang, Zhi-yuan; Ge, Chuan; Luo, An-cheng; Chen, Xin

    2015-02-01

    Concentrated turtle aquaculture effluent poses an environmental threat to water bodies, and therefore needs to be treated prior to disposal. This study was conducted to assess the effect of multi-soil-layer (MSL) systems treating turtle aquaculture effluent with adding different amounts of sludge. Four MSL systems were constructed with dry weight ratios of sludge with 0%, 5%, 10%, and 20% (MSL 1, MSL 2, MSL 3, and MSL 4, respectively). The turtle aquaculture effluent had an average chemical oxygen demand (COD), ammonia nitrogen (NH4(+)-N) and total nitrogen (TN) concentration of 288.4, 213.4, and 252.0 mg/L, respectively. The COD/TN (C/N) ratio was 1.2. The results showed that the four MSL systems could effectively treat the COD, NH4(+)-N, and TN, and MSL 4 showed significantly improved NH4(+)-N removal efficiency, suggesting the potential of sludge addition to improve the turtle aquaculture effluent treatment. The average COD, TN, and NH4(+)-N removal efficiencies of MSL 4 were 70.3%, 66.5%, and 72.7%, respectively. To further interpret the contribution of microorganisms to the removal, the microbial community compositions and diversities of the four MSL systems were measured. Comparisons of the denaturing gradient gel electrophoresis (DGGE) profiles revealed that the amount of nitrifying bacteria and diversity in MSL 4 were higher than those in the other three systems. We concluded that adding 20% of sludge improved the NH4(+)-N removal and stability of the system for nitrification, due to the enrichment of the nitrifying bacteria in MSL 4.

  17. Poly(Acrylic acid–Based Hybrid Inorganic–Organic Electrolytes Membrane for Electrical Double Layer Capacitors Application

    Directory of Open Access Journals (Sweden)

    Chiam-Wen Liew

    2016-05-01

    Full Text Available Nanocomposite polymer electrolyte membranes (NCPEMs based on poly(acrylic acid(PAA and titania (TiO2 are prepared by a solution casting technique. The ionic conductivity of NCPEMs increases with the weight ratio of TiO2.The highest ionic conductivity of (8.36 ± 0.01 × 10−4 S·cm−1 is obtained with addition of 6 wt % of TiO2 at ambient temperature. The complexation between PAA, LiTFSI and TiO2 is discussed in Attenuated total reflectance-Fourier Transform Infrared (ATR-FTIR studies. Electrical double layer capacitors (EDLCs are fabricated using the filler-free polymer electrolyte or the most conducting NCPEM and carbon-based electrodes. The electrochemical performances of fabricated EDLCs are studied through cyclic voltammetry (CV and galvanostatic charge-discharge studies. EDLC comprising NCPEM shows the specific capacitance of 28.56 F·g−1 (or equivalent to 29.54 mF·cm−2 with excellent electrochemical stability.

  18. A fractal analytical model for the permeabilities of fibrous gas diffusion layer in proton exchange membrane fuel cells

    International Nuclear Information System (INIS)

    Xiao, Boqi; Fan, Jintu; Ding, Feng

    2014-01-01

    The study of water and gas transport through fibrous gas diffusion layer (GDL) is important to the optimization of proton exchange membrane fuel cells (PEMFCs). In this work, analytical models of dimensionless permeability, and water and gas relative permeabilities of fibrous GDL in PEMFCs are derived using fractal theory. In our models, the structure of fibrous GDL is characterized in terms of porosity, tortuosity fractal dimension (D T ), pore area fractal dimensions (d f ), water phase (d f,w ) and gas phase (d f,g ) fractal dimensions. The predicted dimensionless permeability, water and gas relative permeabilities based on the proposed models are in good agreement with experimental data and predictions of numerical simulations reported in the literature. The model reveals that, although water phase and gas phase fractal dimensions strongly depend on porosity, the water and gas relative permeabilities are independent of porosity and are a function of water saturation only. It is also shown that the dimensionless permeability decreases significantly with the increase of tortuosity fractal dimension. On the other hand, there is only a small decrease in the water and gas relative permeabilities when tortuosity fractal dimension increases. One advantage of the proposed analytical model is that it contains no empirical constant, which is normally required in past models

  19. Stability and performance improvement of a polymer electrolyte membrane fuel cell stack by laser perforation of gas diffusion layers

    Energy Technology Data Exchange (ETDEWEB)

    Gerteisen, Dietmar; Sadeler, Christian [Fraunhofer Institute for Solar Energy Systems ISE, Department of Energy Technology, Heidenhofstrasse 2, 79110 Freiburg (Germany)

    2010-08-15

    The performance and stability of a hydrogen-driven polymer electrolyte membrane fuel cell stack (6-cell PEFC stack) are investigated with regard to pore flooding within the gas diffusion layers (GDLs). Two short stacks with various GDLs (Toray TGP-H-060 untreated and laser-perforated) were characterized at different operating conditions by several characterization techniques such as constant current load, polarization curve, chronoamperometry and chronovoltammetry. The experimental results reveal that the perforation of the cathode GDLs improves the water transport in the porous media and thus the performance as well as the stability of the operating stack in medium and high current density range. A reduced pore flooding is verified when using the customized laser-perforated GDLs. The GDL perforation has a huge potential to balance the inhomogeneous in-plane saturation conditions between the inlet and outlet area of the cell and to compensate to a certain degree the effects of temperature distribution within a stack regarding the water management. (author)

  20. Validity of two-phase polymer electrolyte membrane fuel cell models with respect to the gas diffusion layer

    Science.gov (United States)

    Ziegler, C.; Gerteisen, D.

    A dynamic two-phase model of a proton exchange membrane fuel cell with respect to the gas diffusion layer (GDL) is presented and compared with chronoamperometric experiments. Very good agreement between experiment and simulation is achieved for potential step voltammetry (PSV) and sine wave testing (SWT). Homogenized two-phase models can be categorized in unsaturated flow theory (UFT) and multiphase mixture (M 2) models. Both model approaches use the continuum hypothesis as fundamental assumption. Cyclic voltammetry experiments show that there is a deterministic and a stochastic liquid transport mode depending on the fraction of hydrophilic pores of the GDL. ESEM imaging is used to investigate the morphology of the liquid water accumulation in the pores of two different media (unteflonated Toray-TGP-H-090 and hydrophobic Freudenberg H2315 I3). The morphology of the liquid water accumulation are related with the cell behavior. The results show that UFT and M 2 two-phase models are a valid approach for diffusion media with large fraction of hydrophilic pores such as unteflonated Toray-TGP-H paper. However, the use of the homgenized UFT and M 2 models appears to be invalid for GDLs with large fraction of hydrophobic pores that corresponds to a high average contact angle of the GDL.

  1. Stability and performance improvement of a polymer electrolyte membrane fuel cell stack by laser perforation of gas diffusion layers

    Science.gov (United States)

    Gerteisen, Dietmar; Sadeler, Christian

    The performance and stability of a hydrogen-driven polymer electrolyte membrane fuel cell stack (6-cell PEFC stack) are investigated with regard to pore flooding within the gas diffusion layers (GDLs). Two short stacks with various GDLs (Toray TGP-H-060 untreated and laser-perforated) were characterized at different operating conditions by several characterization techniques such as constant current load, polarization curve, chronoamperometry and chronovoltammetry. The experimental results reveal that the perforation of the cathode GDLs improves the water transport in the porous media and thus the performance as well as the stability of the operating stack in medium and high current density range. A reduced pore flooding is verified when using the customized laser-perforated GDLs. The GDL perforation has a huge potential to balance the inhomogeneous in-plane saturation conditions between the inlet and outlet area of the cell and to compensate to a certain degree the effects of temperature distribution within a stack regarding the water management.

  2. Soil-fluid-structure interaction applied to the Oued Taht dam (taking into account the membrane effect.

    Directory of Open Access Journals (Sweden)

    Nasreddine Krenich

    2018-01-01

    Full Text Available The objective of this work is to analyze the dynamic behavior (modal behavior of the "Oued Taht" arch dam located at MASCARA, taking into consideration the effect of soil-fluid-structure interaction. The finite element code "Ansys" was chosen for the dynamic modeling of the dam that is the subject of this study. Three hypotheses were used for soil-structure interaction modeling; model with embedded base which corresponds to the case where the phenomenon of interactions soil-structure is neglected, model with ground of foundation without mass which consists in taking into account the kinematic component of interaction soil structure and neglecting the inertial component and the model with foundation soil with mass where the two components of soil-structure interaction are taken into account. For the fluid, the model of added masses (equivalent to the westergaard approach using the SURF element available in the Ansys code library was used. A comparison between the different models of the "Oued Taht" dam was made; it has been found that the taking into account of the soil-fluid-structure interaction phenomenon modifies the period of the system and that the modeling of the dam with and without fluid gives a very important difference of the periods. The results obtained were compared with those of the "Brezina" dam, which is a gravity dam located in BAYADH. The work has shown that the periods of the "Oued Taht" dam with soil-fluid-structure interaction modeling are very out of phase with the periods without fluid modeling (taking into account only the soilstructure interaction phenomenon. which is not the case for the Brezina dam where the periods for the two models are getting closer. The periods between the two models mentioned before are close to the dam of Brézina because the latter is a dam which participates much more by its own weight than by its vault (thickness of the vault varies between 36.3 m at the base and 5m in crest which is the

  3. Two-Ply Composite Membranes with Separation Layers from Chitosan and Sulfoethylcellulose on a Microporous Support Based on Poly(diphenylsulfone-N-phenylphthalimide

    Directory of Open Access Journals (Sweden)

    Svetlana V. Kononova

    2017-12-01

    Full Text Available Two-ply composite membranes with separation layers from chitosan and sulfoethylcellulose were developed on a microporous support based on poly(diphenylsulfone-N-phenylphthalimide and investigated by use of X-ray diffraction and scanning electron microscopy methods. The pervaporation properties of the membranes were studied for the separation of aqueous alcohol (ethanol, propan-2-ol mixtures of different compositions. When the mixtures to be separated consist of less than 15 wt % water in propan-2-ol, the membranes composed of polyelectrolytes with the same molar fraction of ionogenic groups (-NH3+ for chitosan and -SO3− for sulfoethylcellulose show high permselectivity (the water content in the permeate was 100%. Factors affecting the structure of a non-porous layer of the polyelectrolyte complex formed on the substrate surface and the contribution of that complex to changes in the transport properties of membranes are discussed. The results indicate significant prospects for the use of chitosan and sulfoethylcellulose for the formation of highly selective pervaporation membranes.

  4. Transport Properties, Mechanical Behavior, Thermal and Chemical Resistance of Asymmetric Flat Sheet Membrane Prepared from PSf/PVDF Blended Membrane on Gauze Supporting Layer

    Directory of Open Access Journals (Sweden)

    Nita Kusumawati

    2018-05-01

    Full Text Available Asymmetric polysulfone (PSf membrane is prepared using phase inversion method and blending with polyvinylidene fluoride (PVDF on the gauze solid support. Casting solution composition optimization has been done to get PSf/PVDF membrane with best characteristics and permeability. The result shows that blending on PSf with PVDF polymer using phase inversion method has been very helpful in creating an asymmetric porous membrane. Increased level of PVDF in casting solution has increased the formation of asymmetry structure and corresponding flux membrane. The result from thermal test using Differential Scanning Calorimetry (DSC-Thermal Gravimetric Analysis (TGA shows the resistance of the membrane to temperature 460 °C. Membrane resistance against acid looks from undetectable changes on infrared spectra after immersion process in H2SO4 6–98 v/v%. While membrane color changes from white to brownish and black is detected after the immersion process in sodium hydroxide (NaOH 0.15–80 w/v%.

  5. Controlling the Release of Indomethacin from Glass Solutions Layered with a Rate Controlling Membrane Using Fluid-Bed Processing. Part 1: Surface and Cross-Sectional Chemical Analysis.

    Science.gov (United States)

    Dereymaker, Aswin; Scurr, David J; Steer, Elisabeth D; Roberts, Clive J; Van den Mooter, Guy

    2017-04-03

    Fluid bed coating has been shown to be a suitable manufacturing technique to formulate poorly soluble drugs in glass solutions. Layering inert carriers with a drug-polymer mixture enables these beads to be immediately filled into capsules, thus avoiding additional, potentially destabilizing, downstream processing. In this study, fluid bed coating is proposed for the production of controlled release dosage forms of glass solutions by applying a second, rate controlling membrane on top of the glass solution. Adding a second coating layer adds to the physical and chemical complexity of the drug delivery system, so a thorough understanding of the physical structure and phase behavior of the different coating layers is needed. This study aimed to investigate the surface and cross-sectional characteristics (employing scanning electron microscopy (SEM) and time of flight secondary ion mass spectrometry (ToF-SIMS)) of an indomethacin-polyvinylpyrrolidone (PVP) glass solution, top-coated with a release rate controlling membrane consisting of either ethyl cellulose or Eudragit RL. The implications of the addition of a pore former (PVP) and the coating medium (ethanol or water) were also considered. In addition, polymer miscibility and the phase analysis of the underlying glass solution were investigated. Significant differences in surface and cross-sectional topography of the different rate controlling membranes or the way they are applied (solution vs dispersion) were observed. These observations can be linked to the polymer miscibility differences. The presence of PVP was observed in all rate controlling membranes, even if it is not part of the coating solution. This could be attributed to residual powder presence in the coating chamber. The distribution of PVP among the sample surfaces depends on the concentration and the rate controlling polymer used. Differences can again be linked to polymer miscibility. Finally, it was shown that the underlying glass solution layer

  6. Rapid establishment of phenol- and quinoline-degrading consortia driven by the scoured cake layer in an anaerobic baffled ceramic membrane bioreactor.

    Science.gov (United States)

    Wang, Wei; Wang, Shun; Ren, Xuesong; Hu, Zhenhu; Yuan, Shoujun

    2017-11-01

    Although toxic and refractory organics, such as phenol and quinoline, are decomposed by anaerobic bacteria, the establishment of specific degrading consortia is a relatively slow process. An anaerobic membrane bioreactor allows for complete biomass retention that can aid the establishment of phenol- and quinoline-degrading consortia. In this study, the anaerobic digestion of phenol (500 mg L -1 ) and quinoline (50 mg L -1 ) was investigated using an anaerobic baffled ceramic membrane bioreactor (ABCMBR). The results showed that, within 30 days, 99% of phenol, 98% of quinoline and 88% of chemical oxygen demand (COD) were removed. The substrate utilisation rates of the cake layer for phenol and quinoline, and specific methanogenic activity of the cake layer, were 7.58 mg phenol g -1  mixed liquor volatile suspended solids (MLVSS) day -1 , 8.23 mg quinoline g -1  MLVSS day -1 and 0.55 g COD CH4  g -1  MLVSS day -1 , respectively. The contribution of the cake layer to the removals of phenol and quinoline was extremely underestimated because the uncounted scoured cake layer was disregarded. Syntrophus was the key population for phenol and quinoline degradation, and it was more abundant in the cake layer than in the bulk sludge. The highly active scattered cake layer sped up the establishment of phenol- and quinoline-degrading consortia in the ABCMBR.

  7. Review of encapsulation technologies

    International Nuclear Information System (INIS)

    Shaulis, L.

    1996-09-01

    The use of encapsulation technology to produce a compliant waste form is an outgrowth from existing polymer industry technology and applications. During the past 12 years, the Department of Energy (DOE) has been researching the use of this technology to treat mixed wastes (i.e., containing hazardous and radioactive wastes). The two primary encapsulation techniques are microencapsulation and macroencapsulation. Microencapsulation is the thorough mixing of a binding agent with a powdered waste, such as incinerator ash. Macroencapsulation coats the surface of bulk wastes, such as lead debris. Cement, modified cement, and polyethylene are the binding agents which have been researched the most. Cement and modified cement have been the most commonly used binding agents to date. However, recent research conducted by DOE laboratories have shown that polyethylene is more durable and cost effective than cements. The compressive strength, leachability, resistance to chemical degradation, etc., of polyethylene is significantly greater than that of cement and modified cement. Because higher waste loads can be used with polyethylene encapsulant, the total cost of polyethylene encapsulation is significantly less costly than cement treatment. The only research lacking in the assessment of polyethylene encapsulation treatment for mixed wastes is pilot and full-scale testing with actual waste materials. To date, only simulated wastes have been tested. The Rocky Flats Environmental Technology Site had planned to conduct pilot studies using actual wastes during 1996. This experiment should provide similar results to the previous tests that used simulated wastes. If this hypothesis is validated as anticipated, it will be clear that polyethylene encapsulation should be pursued by DOE to produce compliant waste forms

  8. A highly sensitive hydrogen sensor with gas selectivity using a PMMA membrane-coated Pd nanoparticle/single-layer graphene hybrid.

    Science.gov (United States)

    Hong, Juree; Lee, Sanggeun; Seo, Jungmok; Pyo, Soonjae; Kim, Jongbaeg; Lee, Taeyoon

    2015-02-18

    A polymer membrane-coated palladium (Pd) nanoparticle (NP)/single-layer graphene (SLG) hybrid sensor was fabricated for highly sensitive hydrogen gas (H2) sensing with gas selectivity. Pd NPs were deposited on SLG via the galvanic displacement reaction between graphene-buffered copper (Cu) and Pd ion. During the galvanic displacement reaction, graphene was used as a buffer layer, which transports electrons from Cu for Pd to nucleate on the SLG surface. The deposited Pd NPs on the SLG surface were well-distributed with high uniformity and low defects. The Pd NP/SLG hybrid was then coated with polymer membrane layer for the selective filtration of H2. Because of the selective H2 filtration effect of the polymer membrane layer, the sensor had no responses to methane, carbon monoxide, or nitrogen dioxide gas. On the contrary, the PMMA/Pd NP/SLG hybrid sensor exhibited a good response to exposure to 2% H2: on average, 66.37% response within 1.81 min and recovery within 5.52 min. In addition, reliable and repeatable sensing behaviors were obtained when the sensor was exposed to different H2 concentrations ranging from 0.025 to 2%.

  9. A two-layer application of the MAGIC model to predict the effects of land use scenarios and reductions in deposition on acid sensitive soils in the UK

    Directory of Open Access Journals (Sweden)

    R. C. Helliwell

    1998-01-01

    Full Text Available A two-layer application of the catchment-based soil and surface water acidification model, MAGIC, was applied to 21 sites in the UK Acid Waters Monitoring Network (AWAMN, and the results were compared with those from a one-layer application of the model. The two-layer model represented typical soil properties more accurately by segregating the organic and mineral horizons into two separate soil compartments. Reductions in sulphur (S emissions associated with the Second S Protocol and different forestry (land use scenarios were modelled, and their effects on soil acidification evaluated. Soil acidification was assessed in terms of base saturation and critical loads for the molar ratio of base cations (CA2+ + MG 2+ + K+ to aluminium (Al in soil solution. The results of the two-layer application indicate that base saturation of the organic compartment was very responsive to changes in land use and deposition compared with the mineral soil. With the two- layer model, the organic soil compartment was particularly sensitive to acid deposition, which resulted in the critical load being predicted to be exceeded at eight sites in 1997 and two sites in 2010. These results indicate that further reductions in S deposition are necessary to raise the base cation (BC:Al ratio above the threshold which is harmful to tree roots. At forested sites BC:Al ratios were generally well below the threshold designated for soil critical loads in Europe and forecasts indicate that forest replanting can adversely affect the acid status of sensitive term objectives of protecting and sustaining soil and water quality. Policy formulation must seek to protect the most sensitive environmental receptor, in this case organic soils. It is clear, therefore, that simply securing protection of surface waters, via the critical loads approach, may not ensure adequate protection of low base status organic soils from the effects of acidification.

  10. Formation of Zn-rich phyllosilicate, Zn-layered double hydroxide and hydrozincite in contaminated calcareous soils

    Energy Technology Data Exchange (ETDEWEB)

    Jacquat, Olivier; Voegelin, Andreas; Villard, Andre; Marcus, Matthew A.; Kretzschmar, Ruben

    2007-10-15

    Recent studies demonstrated that Zn-phyllosilicate- and Zn-layered double hydroxide-type (Zn-LDH) precipitates may form in contaminated soils. However, the influence of soil properties and Zn content on the quantity and type of precipitate forming has not been studied in detail so far. In this work, we determined the speciation of Zn in six carbonate-rich surface soils (pH 6.2 to 7.5) contaminated by aqueous Zn in the runoff from galvanized power line towers (1322 to 30090 mg/kg Zn). Based on 12 bulk and 23 microfocused extended X-ray absorption fine structure (EXAFS) spectra, the number, type and proportion of Zn species were derived using principal component analysis, target testing, and linear combination fitting. Nearly pure Zn-rich phyllosilicate and Zn-LDH were identified at different locations within a single soil horizon, suggesting that the local availabilities of Al and Si controlled the type of precipitate forming. Hydrozincite was identified on the surfaces of limestone particles that were not in direct contact with the soil clay matrix. With increasing Zn loading of the soils, the percentage of precipitated Zn increased from {approx}20% to {approx}80%, while the precipitate type shifted from Zn-phyllosilicate and/or Zn-LDH at the lowest studied soil Zn contents over predominantly Zn-LDH at intermediate loadings to hydrozincite in extremely contaminated soils. These trends were in agreement with the solubility of Zn in equilibrium with these phases. Sequential extractions showed that large fractions of soil Zn ({approx}30% to {approx}80%) as well as of synthetic Zn-kerolite, Zn-LDH, and hydrozincite spiked into uncontaminated soil were readily extracted by 1 M NH{sub 4}NO{sub 3} followed by 1 M NH{sub 4}-acetate at pH 6.0. Even though the formation of Zn precipitates allows for the retention of Zn in excess to the adsorption capacity of calcareous soils, the long-term immobilization potential of these precipitates is limited.

  11. Prediction of Hexaconazole Concentration in the Top Most Layer of Oil Palm Plantation Soil Using Exploratory Data Analysis (EDA).

    Science.gov (United States)

    Maznah, Zainol; Halimah, Muhamad; Shitan, Mahendran; Kumar Karmokar, Provash; Najwa, Sulaiman

    2017-01-01

    Ganoderma boninense is a fungus that can affect oil palm trees and cause a serious disease called the basal stem root (BSR). This disease causes the death of more than 80% of oil palm trees midway through their economic life and hexaconazole is one of the particular fungicides that can control this fungus. Hexaconazole can be applied by the soil drenching method and it will be of interest to know the concentration of the residue in the soil after treatment with respect to time. Hence, a field study was conducted in order to determine the actual concentration of hexaconazole in soil. In the present paper, a new approach that can be used to predict the concentration of pesticides in the soil is proposed. The statistical analysis revealed that the Exploratory Data Analysis (EDA) techniques would be appropriate in this study. The EDA techniques were used to fit a robust resistant model and predict the concentration of the residue in the topmost layer of the soil.

  12. Prediction of Hexaconazole Concentration in the Top Most Layer of Oil Palm Plantation Soil Using Exploratory Data Analysis (EDA.

    Directory of Open Access Journals (Sweden)

    Zainol Maznah

    Full Text Available Ganoderma boninense is a fungus that can affect oil palm trees and cause a serious disease called the basal stem root (BSR. This disease causes the death of more than 80% of oil palm trees midway through their economic life and hexaconazole is one of the particular fungicides that can control this fungus. Hexaconazole can be applied by the soil drenching method and it will be of interest to know the concentration of the residue in the soil after treatment with respect to time. Hence, a field study was conducted in order to determine the actual concentration of hexaconazole in soil. In the present paper, a new approach that can be used to predict the concentration of pesticides in the soil is proposed. The statistical analysis revealed that the Exploratory Data Analysis (EDA techniques would be appropriate in this study. The EDA techniques were used to fit a robust resistant model and predict the concentration of the residue in the topmost layer of the soil.

  13. Loading test of pile affected by soil layer deformation; Jiban henkei no eikyo wo ukeru kui no saika jikken

    Energy Technology Data Exchange (ETDEWEB)

    Kakurai, M.; Tsuchiya, T. [Takenaka Corp., Osaka (Japan)

    1997-10-10

    Large soil tank developed for shearing experiments is used to study the horizontal movement of piles in earthquakes. The system comprises a soil filled (8m deep) tank, pile head loading jig, and 6 actuators. The soil tank is fabricated of 40 layers of 20cm-high iron frames of inner dimensions 2.5mtimes2.5m, and it is filled with soil that is to simulate the ground. The frames are divided into 4 groups each containing 10 frames, and the frames in each group are coupled with each other, so that all the frames in one group will move horizontally when the topmost frame in the group is moved horizontally. An actuator, which travels horizontally ganging with a computer, is mounted on the top frame in each group, and this setup enables the arbitrary simulation of ground deformation in the horizontal direction in an earthquake. The pile head loading jig, driven by 2 actuators, can keep restraining the pile head from rotation while applying load or deforming force to the pile head as desired in the vertical and horizontal direction. Experiments conducted using this system involve the force imposed on a pile in the soil tank by ground deformation and the resultant pile behavior including breakdown. 9 figs.

  14. Transport of encapsulated nuclear fuels

    International Nuclear Information System (INIS)

    Broman, Ulrika; Dybeck, Peter; Ekendahl, Ann-Mari

    2005-12-01

    The transport system for encapsulated fuel is described, including a preliminary drawing of a transport container. In the report, the encapsulation plant is assumed to be located to Oskarshamn, and the repository to Oskarshamn or Forsmark

  15. Subcutaneous encapsulated fat necrosis

    DEFF Research Database (Denmark)

    Aydin, Dogu; Berg, Jais O

    2016-01-01

    We have described subcutaneous encapsulated fat necrosis, which is benign, usually asymptomatic and underreported. Images have only been published on two earlier occasions, in which the necrotic nodules appear "pearly" than the cloudy yellow surface in present case. The presented image may help...

  16. Distribution flow: a general process in the top layer of water repellent soils

    NARCIS (Netherlands)

    Ritsema, C.J.; Dekker, L.W.

    1995-01-01

    Distribution flow is the process of water and solute flowing in a lateral direction over and through the very first millimetre or centimetre of the soil profile. A potassium bromide tracer was applied in two water-repellent sandy soils to follow the actual flow paths of water and solutes in the

  17. Combination tones along the basilar membrane in a 3D finite element model of the cochlea with acoustic boundary layer attenuation

    Science.gov (United States)

    Böhnke, Frank; Scheunemann, Christian; Semmelbauer, Sebastian

    2018-05-01

    The propagation of traveling waves along the basilar membrane is studied in a 3D finite element model of the cochlea using single and two-tone stimulation. The advantage over former approaches is the consideration of viscous-thermal boundary layer damping which makes the usual but physically unjustified assumption of Rayleigh damping obsolete. The energy loss by viscous boundary layer damping is 70 dB lower than the actually assumed power generation by outer hair cells. The space-time course with two-tone stimulation shows the traveling waves and the periodicity of the beat frequency f2 - f1.

  18. Two-layer membranes of calcium phosphate/collagen/PLGA nanofibres: in vitro biomineralisation and osteogenic differentiation of human mesenchymal stem cells

    Science.gov (United States)

    Hild, Nora; Schneider, Oliver D.; Mohn, Dirk; Luechinger, Norman A.; Koehler, Fabian M.; Hofmann, Sandra; Vetsch, Jolanda R.; Thimm, Benjamin W.; Müller, Ralph; Stark, Wendelin J.

    2011-02-01

    The present study evaluates the in vitro biomedical performance of an electrospun, flexible, anisotropic bilayer with one layer containing a collagen to mineral ratio similar to that in bone. The double membrane consists of a poly(lactide-co-glycolide) (PLGA) layer and an amorphous calcium phosphate (a-CaP)/collagen (Col)/PLGA layer. In vitro biomineralisation and a cell culture study with human mesenchymal stem cells (hMSC) were conducted to characterise such membranes for possible application as biomaterials. Nanofibres with different a-CaP/Col/PLGA compositions were synthesised by electrospinning to mimic the actual composition of bone tissue. Immersion in simulated body fluid and in cell culture medium resulted in the deposition of a hydroxyapatite layer. Incubation of hMSC for 4 weeks allowed for assessment of the proliferation and osteogenic differentiation of the cells on both sides of the double membrane. Confocal laser scanning microscopy was used to observe the proper adhesion of the cells. Calcium and collagen content was proven by Alizarin red S and Sirius red assays. Acute cytotoxic effects of the nanoparticles or the chemicals used in the scaffold preparation could be excluded based on viability assays (alamarBlue and alkaline phosphatase activity). The findings suggest possible application of such double membranes is in treatment of bone defects with complex geometries as wound dressing material.The present study evaluates the in vitro biomedical performance of an electrospun, flexible, anisotropic bilayer with one layer containing a collagen to mineral ratio similar to that in bone. The double membrane consists of a poly(lactide-co-glycolide) (PLGA) layer and an amorphous calcium phosphate (a-CaP)/collagen (Col)/PLGA layer. In vitro biomineralisation and a cell culture study with human mesenchymal stem cells (hMSC) were conducted to characterise such membranes for possible application as biomaterials. Nanofibres with different a

  19. Application of a Coated Film Catalyst Layer Model to a High Temperature Polymer Electrolyte Membrane Fuel Cell with Low Catalyst Loading Produced by Reactive Spray Deposition Technology

    Directory of Open Access Journals (Sweden)

    Timothy D. Myles

    2015-10-01

    Full Text Available In this study, a semi-empirical model is presented that correlates to previously obtained experimental overpotential data for a high temperature polymer electrolyte membrane fuel cell (HT-PEMFC. The goal is to reinforce the understanding of the performance of the cell from a modeling perspective. The HT-PEMFC membrane electrode assemblies (MEAs were constructed utilizing an 85 wt. % phosphoric acid doped Advent TPS® membranes for the electrolyte and gas diffusion electrodes (GDEs manufactured by Reactive Spray Deposition Technology (RSDT. MEAs with varying ratios of PTFE binder to carbon support material (I/C ratio were manufactured and their performance at various operating temperatures was recorded. The semi-empirical model derivation was based on the coated film catalyst layer approach and was calibrated to the experimental data by a least squares method. The behavior of important physical parameters as a function of I/C ratio and operating temperature were explored.

  20. Safety evaluation for packaging (onsite) singly encapsulated cesium chloride capsules

    International Nuclear Information System (INIS)

    Smyth, W.W.

    1997-01-01

    Three nonstandard Waste Encapsulation and Storage Facility (WESF) cesium chloride capsules are being shipped from WESF (225B building) to the 324 building. They would normally be shipped in the Beneficial Uses Shipping System (BUSS) cask under its US Department of Energy (DOE) license (DOE 1996), but these capsules are nonstandard: one has a damaged or defective weld in the outer layer of encapsulation, and two have the outer encapsulation removed. The 3 capsules, along with 13 other capsules, will be overpacked in the 324 building to meet the requirements for storage in WESF's pool

  1. Influence of artificially aged gas diffusion layers on the water management of polymer electrolyte membrane fuel cells analyzed with in-operando synchrotron imaging

    International Nuclear Information System (INIS)

    Arlt, Tobias; Klages, Merle; Messerschmidt, Matthias; Scholta, Joachim; Manke, Ingo

    2017-01-01

    The influence of artificial ageing of gas diffusion layers (GDLs) on the cell performance was investigated using high resolution synchrotron radiography. State-of-the-art GDLs of the type SIGRACET ® SGL 25BC were aged for 0 h, 16 h and 24 h in a hydrogen peroxide solution before they were assembled in the fuel cells. In-operando radiographic measurements were combined with voltage and contact angle measurements. Correlations between applied ageing conditions, GDL water saturation and cell performance were revealed. Hereby, all cell operating conditions were tested several times to estimate the reproducibility of in-operando radiographic fuel cell measurements. Water films at the GDL-membrane and at the GDL-flow field interfaces were found and attributed to MPL cracks and large pores in the GDL structure. The combination of these cracks and pores are assumed to play a crucial role for blocked gas paths, leading to an undersupply with reactants and an increased humidification of the membrane. It is shown that water agglomerations directly impact the membrane resistance. We assume that the hydrophobicity of the fibers inside the GDL is more important for the cell performance than water agglomerations at the membrane-GDL interface. - Highlights: • Influence of ageing of gas diffusion layers on cell performance was investigated. • Cell performance decreased using artificially aged GDLs. • Performance decrease correlated to altered water distribution. • Reproducibility of water thickness measurements with synchrotron imaging.

  2. Efficiency of a Multi-Soil-Layering System on Wastewater Treatment Using Environment-Friendly Filter Materials

    Directory of Open Access Journals (Sweden)

    Chia-Chun Ho

    2015-03-01

    Full Text Available The multi-soil-layering (MSL system primarily comprises two parts, specifically, the soil mixture layer (SML and the permeable layer (PL. In Japan, zeolite is typically used as the permeable layer material. In the present study, zeolite was substituted with comparatively cheaper and more environmentally friendly materials, such as expanded clay aggregates, oyster shells, and already-used granular activated carbon collected from water purification plants. A series of indoor tests indicated that the suspended solid (SS removal efficiency of granular activated carbon was between 76.2% and 94.6%; zeolite and expanded clay aggregates achieved similar efficiencies that were between 53.7% and 87.4%, and oyster shells presented the lowest efficiency that was between 29.8% and 61.8%. Further results show that the oyster shell system required an increase of wastewater retention time by 2 to 4 times that of the zeolite system to maintain similar chemical oxygen demand (COD removal efficiency. Among the four MSL samples, the zeolite system and granular activated carbon system demonstrated a stable NH3-N removal performance at 92.3%–99.8%. The expanded clay aggregate system present lower removal performance because of its low adsorption capacity and excessively large pores, causing NO3−-N to be leached away under high hydraulic loading rate conditions. The total phosphorous (TP removal efficiency of the MSL systems demonstrated no direct correlation with the permeable layer material. Therefore, all MSL samples achieved a TP efficiency of between 92.1% and 99.2%.

  3. Efficiency of a multi-soil-layering system on wastewater treatment using environment-friendly filter materials.

    Science.gov (United States)

    Ho, Chia-Chun; Wang, Pei-Hao

    2015-03-23

    The multi-soil-layering (MSL) system primarily comprises two parts, specifically, the soil mixture layer (SML) and the permeable layer (PL). In Japan, zeolite is typically used as the permeable layer material. In the present study, zeolite was substituted with comparatively cheaper and more environmentally friendly materials, such as expanded clay aggregates, oyster shells, and already-used granular activated carbon collected from water purification plants. A series of indoor tests indicated that the suspended solid (SS) removal efficiency of granular activated carbon was between 76.2% and 94.6%; zeolite and expanded clay aggregates achieved similar efficiencies that were between 53.7% and 87.4%, and oyster shells presented the lowest efficiency that was between 29.8% and 61.8%. Further results show that the oyster shell system required an increase of wastewater retention time by 2 to 4 times that of the zeolite system to maintain similar chemical oxygen demand (COD) removal efficiency. Among the four MSL samples, the zeolite system and granular activated carbon system demonstrated a stable NH3-N removal performance at 92.3%-99.8%. The expanded clay aggregate system present lower removal performance because of its low adsorption capacity and excessively large pores, causing NO3--N to be leached away under high hydraulic loading rate conditions. The total phosphorous (TP) removal efficiency of the MSL systems demonstrated no direct correlation with the permeable layer material. Therefore, all MSL samples achieved a TP efficiency of between 92.1% and 99.2%.

  4. Migracija dizel goriva izlivenog u slojeve zemljišta / Migration of diesel fuel spilled in subsurface layers of soil

    Directory of Open Access Journals (Sweden)

    Mladen Vuruna

    2005-09-01

    Full Text Available U radu su prikazane osnovne fizičko-hemijske karakteristike dizel goriva i zemljišta. Objašnjena je migracija izlivenog naftnog zagađivača kroz vertikalni profil zemljišta. U eksperimentalnom delu ispitivane su koncentracije dizel goriva i relativne koncentracije n-alkana u površinskim slojevima peska, u koje gorivo dospeva kao posledica akcidentnog izlivanja. Utvrđeno je da se koncentracije dizel goriva menjaju sa vremenom nakon izlivanja u svim ispitivanim slojevima. Takođe, utvrđeno je da se dizel gorivo, kao potencijalni zagađivač, u prvih šest nedelja, uglavnom, zadržava u površinskom sloju dubine 30 cm, a objašnjene su i mogućnosti sanacije zagađenog zemljišta. / The basic physical and chemical properties of both diesel fuel and soil have been given in this article and oil pollutants migration through vertical soil profile have been explained as well. In the experimental part of the paper both the concentrations of diesel fuel and relative concentrations of n-alkynes spilled in sandy soil by accident have been investigated. It has been proven that the concentrations of diesel fuel have changed in all layers of soil depending on the time after spill. Diesel fuel as possible pollutant has been retained 30 cm deep in sandy soil during six weeks after spill. Finally, cleanup techniques of polluted soil have been explained.

  5. Sorption Kinetics of Escherichia coli and Salmonella sp on Two Soil Layers Associated with a Groundwater Table in Yaounde, Cameroon (Central Africa

    Directory of Open Access Journals (Sweden)

    Norbert Kemka

    2005-12-01

    Full Text Available A laboratory study has been carried out on two soil layers (HX and HY located above a groundwater table in Yaounde, Cameroon (Central Africa. The main purpose of this study was to assess the retention potential or sorption kinetics of Escherichia coli and Salmonella sp. on these soil layers. For both soil layers, bacterial sorption on soil particles occurred rapidly during the first 30 minutes of incubation of bacteria and soil particles in aqueous media, and increased gradually with incubation time up to 300 min. In some cases, adsorption rates fluctuated after 30 min of incubation, probably due to bacterial cell sorption to and de-sorption from soil particles. Using Freundlich isotherms, it was noted that adsorption coefficient related to adsorption capacity varied from 19 to 4026 E. coli.mg-1 of soil, and from 506 to 847 Salmonella sp.mg-1 of soil. For both bacterial species, the adsorption coefficient of layer HY (located in close proximity of the water table was greater than that of HX (located above layer HY and seemed to positively correlate with the pH values and N/P ratios, and to negatively correlate with the values of C/N and C/P ratios. The linearity coefficient related to adsorption intensity varied from 0.5841 to 1.0023 for E. coli, and from 0.7068 to 1.5236 for Salmonella sp. The physico-chemical characteristics of soil particles seemed to influence the sorption kinetics of bacteria on soil.

  6. Natural Regeneration in a Multi-Layered Pinus sylvestris-Picea abies Forest after Target Diameter Harvest and Soil Scarification

    Directory of Open Access Journals (Sweden)

    Lars Drössler

    2017-01-01

    Full Text Available Forest management in Sweden can be characterized by even-aged silviculture heavily relying on three established harvest regimes: clearcutting, the seed-tree method, and the shelterwood system. Less intense, small-scale retention harvest systems such as single tree and group selection harvest are rarely used. In addition, natural regeneration dynamics without enrichment planting have barely been studied. Consequently, this study examined natural regeneration establishment in a multi-layered Pinus sylvestris-Picea abies forest stand in southwest Sweden after target diameter harvesting and soil scarification. The creation of forest canopy gaps had a positive effect on total seedling density five years after harvest, mainly due to a significantly higher number of Betula pendula individuals. Seedling density of more desirable tree species suitable for continuous cover forestry such as Fagus sylvatica, Quercus petraea and Picea abies also increased substantially in gaps when compared to pre-harvest conditions or the unharvested plots. In contrast, soil scarification did not increase the number of seedlings of desired tree species due to a significant decrease in Picea abies abundance. Soil moisture and gap size significantly improved Betula pendula seedling establishment while a larger number of Quercus petraea seedlings were observed in Vaccinium myrtillus patches. We conclude that canopy gaps are beneficial under the encountered stand conditions to initiate forest regeneration, and that soil scarification without the timely occurrence of a mast year of desired tree species is not effective in the type of forest studied.

  7. A membrane-based ELISA assay for the herbicide Isoproturon in soil samples

    OpenAIRE

    Baskeyfield, Damian E. H.; Davis, Frank; Magan, Naresh; Tothill, Ibtisam E.

    2012-01-01

    A membrane based enzyme linked immunosorbent assay (MELISA) for the detection of a common herbicide, isoproturon is described. A heterogeneous competitive ELISA was the format chosen for isoproturon detection. An immunoassay system with a horseradish peroxidase (HRP) labeled polyclonal antibody preparation was developed and characterized before suitable sensitivity and selectivity for isoproturon were attained. After development as a microtiter plate immunoassay, the system was transferred to...

  8. The Experimental Measurement of Local and Bulk Oxygen Transport Resistances in the Catalyst Layer of Proton Exchange Membrane Fuel Cells.

    Science.gov (United States)

    Wang, Chao; Cheng, Xiaojing; Lu, Jiabin; Shen, Shuiyun; Yan, Xiaohui; Yin, Jiewei; Wei, Guanghua; Zhang, Junliang

    2017-12-07

    Remarkable progress has been made in reducing the cathodic Pt loading of PEMFCs; however, a huge performance loss appears at high current densities, indicating the existence of a large oxygen transport resistance associated with the ultralow Pt loading catalyst layer. To reduce the Pt loading without sacrificing cell performance, it is essential to illuminate the oxygen transport mechanism in the catalyst layer. Toward this goal, an experimental approach to measure the oxygen transport resistance in catalyst layers is proposed and realized for the first time in this study. The measuring approach involves a dual-layer catalyst layer design, which consists of a dummy catalyst layer and a practical catalyst layer, followed by changing the thickness of dummy layer to respectively quantify the local and bulk resistances via limiting current measurements combined with linear extrapolation. The experimental results clearly reveal that the local resistance dominates the total resistance in the catalyst layer.

  9. High Resolution NMR Studies of Encapsulated Proteins In Liquid Ethane

    Science.gov (United States)

    Peterson, Ronald W.; Lefebvre, Brian G.; Wand, A. Joshua

    2005-01-01

    Many of the difficulties presented by large, aggregation-prone, and membrane proteins to modern solution NMR spectroscopy can be alleviated by actively seeking to increase the effective rate of molecular reorientation. An emerging approach involves encapsulating the protein of interest within the protective shell of a reverse micelle, and dissolving the resulting particle in a low viscosity fluid, such as the short chain alkanes. Here we present the encapsulation of proteins with high structural fidelity within reverse micelles dissolved in liquid ethane. The addition of appropriate co-surfactants can significantly reduce the pressure required for successful encapsulation. At these reduced pressures, the viscosity of the ethane solution is low enough to provide sufficiently rapid molecular reorientation to significantly lengthen the spin-spin NMR relaxation times of the encapsulated protein. PMID:16028922

  10. Modeling Encapsulated Microbubble Dynamics at High Pressure Amplitudes

    Science.gov (United States)

    Heyse, Jan F.; Bose, Sanjeeb; Iaccarino, Gianluca

    2017-11-01

    Encapsulated microbubbles are commonly used in ultrasound contrast imaging and are of growing interest in therapeutic applications where local cavitation creates temporary perforations in cell membranes allowing for enhanced drug delivery. Clinically used microbubbles are encapsulated by a shell commonly consisting of protein, polymer, or phospholipid; the response of these bubbles to externally imposed ultrasound waves is sensitive to the compressibility of the encapsulating shell. Existing models approximate the shell compressibility via an effective surface tension (Marmottant et al. 2005). We present simulations of microbubbles subjected to high amplitude ultrasound waves (on the order of 106 Pa) and compare the results with the experimental measurements of Helfield et al. (2016). Analysis of critical points (corresponding to maximum and minimum expansion) in the governing Rayleigh-Plesset equation is used to make estimates of the parameters used to characterize the effective surface tension of the encapsulating shell. Stanford Graduate Fellowship.

  11. Encapsulation of pancreatic islets for transplantation in diabetes : the untouchable islets

    NARCIS (Netherlands)

    de Vos, P; Marchetti, P

    The aim of encapsulation of pancreatic islets is to transplant in the absence of immunosuppression. It is based on the principle that transplanted tissue is protected from the host immune system by an artificial membrane. Encapsulation allows for application of insulin-secreting cells of animal or

  12. Examination of evaporative fraction diurnal behaviour using a soil-vegetation model coupled with a mixed-layer model

    Directory of Open Access Journals (Sweden)

    J.-P. Lhomme

    1999-01-01

    Full Text Available In many experimental conditions, the evaporative fraction, defined as the ratio between evaporation and available energy, has been found stable during daylight hours. This constancy is investigated over fully covering vegetation by means of a land surface scheme coupled with a mixed-layer model, which accounts for entrainment of overlying air. The evaporation rate follows the Penman-Monteith equation and the surface resistance is given by a Jarvis type parameterization involving solar radiation, saturation deficit and leaf water potential. The diurnal course of the evaporative fraction is examined, together with the influence of environmental factors (soil water availability, solar radiation input, wind velocity, saturation deficit above the well-mixed layer. In conditions of fair weather, the curves representing the diurnal course of the evaporative fraction have a typical concave-up shape. Around midday (solar time these curves appear as relatively constant, but always lower that the daytime mean value. Evaporative fraction decreases when soil water decreases or when solar energy increases. An increment of saturation deficit above the mixed-layer provokes only a slight increase of evaporative fraction, and wind velocity has almost no effect. The possibility of estimation daytime evaporation from daytime available energy multiplied by the evaporative fraction at a single time of the day is also investigated. It appears that it is possible to obtain fairly good estimates of daytime evaporation by choosing adequately the time of the measurement of the evaporative fraction. The central hours of the day, and preferably about 3 hr before or after noon, are the most appropriate to provide good estimates. The estimation appears also to be much better when soil water availability (or evaporation is high than when it is low.

  13. Retention of dead standing plant biomass (marcescence) increases subsequent litter decomposition in the soil organic layer

    Czech Academy of Sciences Publication Activity Database

    Angst, Šárka; Cajthaml, T.; Angst, Gerrit; Šimáčková, H.; Brus, Jiří; Frouz, Jan

    2017-01-01

    Roč. 418, 1-2 (2017), s. 571-579 ISSN 0032-079X Institutional support: RVO:60077344 ; RVO:61389013 Keywords : photodegradation * C-13 CP/MAS NMR spectroscopy * litter decomposition * pyrolysis GC-MS * Calamagrostis epigeios * photo-facilitation Subject RIV: DF - Soil Science; CD - Macromolecular Chemistry (UMCH-V) OBOR OECD: Soil science; Polymer science (UMCH-V) Impact factor: 3.052, year: 2016

  14. Development of Liposome Encapsulated Hemoglobin (LEH) and Studies of Hemorrhagic Shock by Use of Imaging Studies with Oxygen-15 and Other Radiotracers

    National Research Council Canada - National Science Library

    Phillips, William T; Goins, Beth; Awasthi, Vibhudutta

    2004-01-01

    .... Encapsulating hemoglobin inside a protective lipid membrane, which mimics a red blood cell, has the advantages of decreasing the toxicity of the free hemoglobin, increasing its circulation time...

  15. Heavy metals fluxes and speciation in the surface layer of urban soils in the province of Brescia (Italy)

    Science.gov (United States)

    Peli, Marco; Raffelli, Giulia; Barontini, Stefano; Bostick, Benjamin C.; Donna, Filippo; Lucchini, Roberto G.; Ranzi, Roberto

    2017-04-01

    the considered soil profiles. The XRF metal total content profiles show an accumulation of metals in the subsurface soil layers, around 5 cm under the soil surface (this feature is highlighted in the normalized profiles). They also give evidence of the plant activity consequences, with the closest downwind site showing values which are for all metals at least one order of magnitude -two for Mn- higher than the ones in the test site. The speciation profiles, besides describing loosely the same pattern, show how the amorphous oxides species is always prevalent for Mn and Pb along the whole profile, while for As the species associated with crystalline oxides is always the prevalent one.

  16. Encapsulating spent nuclear fuel

    International Nuclear Information System (INIS)

    Fleischer, L.R.; Gunasekaran, M.

    1979-01-01

    A system is described for encapsulating spent nuclear fuel discharged from nuclear reactors in the form of rods or multi-rod assemblies. The rods are completely and contiguously enclosed in concrete in which metallic fibres are incorporated to increase thermal conductivity and polymers to decrease fluid permeability. This technique provides the advantage of acceptable long-term stability for storage over the conventional underwater storage method. Examples are given of suitable concrete compositions. (UK)

  17. Relation between soil P test values and mobilization of dissolved and particulate P from the plough layer of typical Danish soils from a long-term field experiment with applied P fertilizers

    DEFF Research Database (Denmark)

    Glaesner, N.; Kjaergaard, C.; Rubaek, G. H.

    2013-01-01

    Accumulation of phosphorus (P) in agricultural topsoils can contribute to leaching of P which may cause eutrophication of surface waters. An understanding of P mobilization processes in the plough layer is needed to improve agricultural management strategies. We compare leaching of total dissolved...... and particulate P through the plough layer of a typical Danish sandy loam soil subjected to three different P fertilizer regimes in a long-term field experiment established in 1975. The leaching experiment used intact soil columns (20cm diameter, 20cm high) during unsaturated conditions. The three soils had small...

  18. Stripping analysis of nanomolar perchlorate in drinking water with a voltammetric ion-selective electrode based on thin-layer liquid membrane.

    Science.gov (United States)

    Kim, Yushin; Amemiya, Shigeru

    2008-08-01

    A highly sensitive analytical method is required for the assessment of nanomolar perchlorate contamination in drinking water as an emerging environmental problem. We developed the novel approach based on a voltammetric ion-selective electrode to enable the electrochemical detection of "redox-inactive" perchlorate at a nanomolar level without its electrolysis. The perchlorate-selective electrode is based on the submicrometer-thick plasticized poly(vinyl chloride) membrane spin-coated on the poly(3-octylthiophene)-modified gold electrode. The liquid membrane serves as the first thin-layer cell for ion-transfer stripping voltammetry to give low detection limits of 0.2-0.5 nM perchlorate in deionized water, commercial bottled water, and tap water under a rotating electrode configuration. The detection limits are not only much lower than the action limit (approximately 246 nM) set by the U.S. Environmental Protection Agency but also are comparable to the detection limits of the most sensitive analytical methods for detecting perchlorate, that is, ion chromatography coupled with a suppressed conductivity detector (0.55 nM) or electrospray ionization mass spectrometry (0.20-0.25 nM). The mass transfer of perchlorate in the thin-layer liquid membrane and aqueous sample as well as its transfer at the interface between the two phases were studied experimentally and theoretically to achieve the low detection limits. The advantages of ion-transfer stripping voltammetry with a thin-layer liquid membrane against traditional ion-selective potentiometry are demonstrated in terms of a detection limit, a response time, and selectivity.

  19. Surface charges promote nonspecific nanoparticle adhesion to stiffer membranes

    Science.gov (United States)

    Sinha, Shayandev; Jing, Haoyuan; Sachar, Harnoor Singh; Das, Siddhartha

    2018-04-01

    This letter establishes the manner in which the electric double layer induced by the surface charges of the plasma membrane (PM) enhances the nonspecific adhesion (NSA) of a metal nanoparticle (NP) to stiffer PMs (i.e., PMs with larger bending moduli). The NSA is characterized by the physical attachment of the NP to the membrane and occurs when the decrease in the surface energy (or any other mechanism) associated with the attachment process provides the energy for bending the membrane. Such an attachment does not involve receptor-ligand interactions that characterize the specific membrane-NP adhesion. Here, we demonstrate that a significant decrease in the electrostatic energy caused by the NP-attachment-induced destruction of the charged-membrane-electrolyte interface is responsible for providing the additional energy needed for bending the membrane during the NP adhesion to stiffer membranes. A smaller salt concentration and a larger membrane charge density augment this effect, which can help to design drug delivery to cells with stiffer membranes due to pathological conditions, fabricate NPs with biomimetic cholesterol-rich lipid bilayer encapsulation, etc.

  20. The Implement of a Multi-layer Frozen Soil Scheme into SSiB3 and its Evaluation over Cold Regions

    Science.gov (United States)

    Li, Q.

    2016-12-01

    The SSiB3 is a biophysics-based model of land-atmosphere interactions and is designed for global and regional studies. It has three soil layers, three snow layers, as well as one vegetation layer. Soil moisture of the three soil layers, interception water store for the canopy, subsurface soil temperature, ground temperature, canopy temperature and snow water equivalent are all predicted based on the water and energy balance at canopy, soil and snow. SSiB3 substantially enhances the model's capability for cold season studies and produces reasonable results compared with observations. However, frozen soil processes are ignored in the SSiB3 and may have effects on the interannual variability of soil temperature and deep soil memory. A multi-layer comprehensive frozen soil scheme (FSM), which is developed for climate study has been implemented into the SSiB3 to describe soil heat transfer and water flow affected by frozen processed in soil. In the coupled SSiB3-FSM, both liquid water and ice content have been taken into account in the frozen soil hydrologic and thermal property parameterization. The maximum soil layer depth could reach 10 meters thick depending on land conditions. To better evaluate the models' performance, the coupled offline SSiB3-FSM and SSiB3 have been driven from 1948 to 1958 by the Princeton global meteorological data set, respectively. For the 10yrs run, the coupled SSiB3-FSM almost captures the features over different regions, especially cold regions. In order to analysis and compare the differences of SSIB3-FSM and SSIB3 in detail, monthly mean surface temperature for different regions are compared with CAMS data. The statistical results of surface skin temperature show that high latitude regions, Africa, Eastern Australia, and North American monsoon regions have been greatly improved in SSIB3-FSM. For the global statistics, the RMSE of the surface temperature simulated by SSiB3-FSM can be improved about 0.6K compared to SSiB3. In this study

  1. Soils

    Science.gov (United States)

    Emily Moghaddas; Ken Hubbert

    2014-01-01

    When managing for resilient forests, each soil’s inherent capacity to resist and recover from changes in soil function should be evaluated relative to the anticipated extent and duration of soil disturbance. Application of several key principles will help ensure healthy, resilient soils: (1) minimize physical disturbance using guidelines tailored to specific soil types...

  2. A study of radon 222 permeation through plastic membranes. Application to a method of radon measurement in water and saturated soils

    International Nuclear Information System (INIS)

    Labed, V.

    1991-04-01

    In order to improve the BARASOL R device and to use it in water-saturated soils and in pressure constraint conditions, we have studied radon 222 permeation through plastic membranes. While the permeation process usually takes place between two media being in the same state, most often gaseous, the present study describes the transfer of radon 222 from the water to the air via a membrane. Polypropylene membranes have been tested with an experimental set-up by monitoring the evolution of radon concentrations in water and in air. The permeation coefficient and the activation energy were calculated in various conditions. With a second experimental set-up, we have tested the polyethylene membrane which has been adapted on the BARASOL. In these conditions, we have shown that it is possible to measure radon in water at concentrations around 10 3 Bq.m -3 [fr

  3. Membrane transporters mediating root signalling and adaptive responses to oxygen deprivation and soil flooding.

    Science.gov (United States)

    Shabala, Sergey; Shabala, Lana; Barcelo, Juan; Poschenrieder, Charlotte

    2014-10-01

    This review provides a comprehensive assessment of a previously unexplored topic: elucidating the role that plasma- and organelle-based membrane transporters play in plant-adaptive responses to flooding. We show that energy availability and metabolic shifts under hypoxia and anoxia are critical in regulating membrane-transport activity. We illustrate the high tissue and time dependence of this regulation, reveal the molecular identity of transporters involved and discuss the modes of their regulation. We show that both reduced oxygen availability and accumulation of transition metals in flooded roots result in a reduction in the cytosolic K(+) pool, ultimately determining the cell's fate and transition to programmed cell death (PCD). This process can be strongly affected by hypoxia-induced changes in the amino acid pool profile and, specifically, ϒ-amino butyric acid (GABA) accumulation. It is suggested that GABA plays an important regulatory role, allowing plants to proceed with H2 O2 signalling to activate a cascade of genes that mediate plant adaptation to flooding while at the same time, preventing the cell from entering a 'suicide program'. We conclude that progress in crop breeding for flooding tolerance can only be achieved by pyramiding the numerous physiological traits that confer efficient energy maintenance, cytosolic ion homeostasis, and reactive oxygen species (ROS) control and detoxification. © 2014 John Wiley & Sons Ltd.

  4. Soft Soil Improvement for Sub-grade Layer Using Hexagonal Micropiles Layout

    Science.gov (United States)

    Ambak, K.; Abdullah, N. A. H.; Yusoff, M. F.; Abidin, M. H. Z.

    2018-04-01

    Soft soil problems are often associated with sediment and stability where it represents a major challenge in Geotechnical Engineering. Research on a soft soil was carried out to determine the level of sediment resulting from the applied load and thus compare the most ideal form of arrangement by the results obtained from bearing capacity. The study was conducted at Research Centre for Soft Soil (RECESS), UTHM by using kaolin. There are several tests conducted on kaolin before the arrangement of pile which is liquid limit test. Through these tests, the level of water content can be maintained which is 1.2 liquid limit where it is in the homogeneous condition. Density test also carried to know weight of kaolin and water that needed in the model. Meanwhile, large strain consolidation test carried on the soil by placing a load of 8 kPa. Then, the pile was arranged in the soil in the shape of a hexagon and square. Load was increased to 12 kPa and imposed on the surface of the pile with a different forms. After 24 hours, the reading of sediment was measured everyday and the process collecting data conducted for 3 week. Based on data obtained, time against sediment can be plotted. To determine the bearing capacity, direct shear test was conducted to get the value coefficient of cohesion, c as a parameter in the calculation of the soil bearing capacity. The results showed that the rate of settlement occurs is different where hexagonal form less the rate of settlement compared to square form which is 64.2% while the results of bearing capacity have the same value.

  5. Computed tomography appearances of sclerosing encapsulating peritonitis

    International Nuclear Information System (INIS)

    George, C.; Al-Zwae, K.; Nair, S.; Cast, J.E.I.

    2007-01-01

    Sclerosing encapsulating peritonitis (SEP) is a serious complication of peritoneal dialysis (PD) characterized by thickened peritoneal membranes, which lead to decreased ultra-filtration and intestinal obstruction. Its early clinical features are nonspecific, and it is often diagnosed late following laparotomy and peritoneal biopsy, when the patient develops small bowel obstruction, which can be a life-threatening complication. However, this is changing with increasing awareness of computed tomography (CT) findings in SEP. CT can yield an early, non-invasive diagnosis that may improve patient outcome. We present a review of the CT appearances of SEP

  6. Computed tomography appearances of sclerosing encapsulating peritonitis

    Energy Technology Data Exchange (ETDEWEB)

    George, C. [Department of Radiology, Hull Royal Infirmary, Hull (United Kingdom)]. E-mail: cheriangeorge@hotmail.com; Al-Zwae, K. [Department of Radiology, Hull Royal Infirmary, Hull (United Kingdom); Nair, S. [Department of Radiology, Hull Royal Infirmary, Hull (United Kingdom); Cast, J.E.I. [Department of Radiology, Hull Royal Infirmary, Hull (United Kingdom)

    2007-08-15

    Sclerosing encapsulating peritonitis (SEP) is a serious complication of peritoneal dialysis (PD) characterized by thickened peritoneal membranes, which lead to decreased ultra-filtration and intestinal obstruction. Its early clinical features are nonspecific, and it is often diagnosed late following laparotomy and peritoneal biopsy, when the patient develops small bowel obstruction, which can be a life-threatening complication. However, this is changing with increasing awareness of computed tomography (CT) findings in SEP. CT can yield an early, non-invasive diagnosis that may improve patient outcome. We present a review of the CT appearances of SEP.

  7. Amide Link Scission in the Polyamide Active Layers of Thin-Film Composite Membranes upon Exposure to Free Chlorine: Kinetics and Mechanisms.

    Science.gov (United States)

    Powell, Joshua; Luh, Jeanne; Coronell, Orlando

    2015-10-20

    The volume-averaged amide link scission in the aromatic polyamide active layer of a reverse osmosis membrane upon exposure to free chlorine was quantified at a variety of free chlorine exposure times, concentrations, and pH and rinsing conditions. The results showed that (i) hydroxyl ions are needed for scission to occur, (ii) hydroxide-induced amide link scission is a strong function of exposure to hypochlorous acid, (iii) the ratio between amide links broken and chlorine atoms taken up increased with the chlorination pH and reached a maximum of ∼25%, (iv) polyamide disintegration occurs when high free chlorine concentrations, alkaline conditions, and high exposure times are combined, (v) amide link scission promotes further chlorine uptake, and (vi) scission at the membrane surface is unrepresentative of volume-averaged scission in the active layer. Our observations are consistent with previously proposed mechanisms describing amide link scission as a result of the hydrolysis of the N-chlorinated amidic N-C bond due to nucleophilic attack by hydroxyl ions. This study increases the understanding of the physicochemical changes that could occur for membranes in treatment plants using chlorine as an upstream disinfectant and the extent and rate at which those changes would occur.

  8. Pervaporation Membranes with Poly(γ-Benzyl-L-Glutamate) Selective Layers for Separation of Toluene - n-Heptane Mixtures

    Czech Academy of Sciences Publication Activity Database

    Kononova, S.V.; Kremnev, R.V.; Suvorova, E.I.; Baklagina, Y.G.; Volchek, B.Z.; Uchytil, Petr; Shabsels, B.M.; Romashkova, K.A.; Setničková, Kateřina; Řezníčková Čermáková, Jiřina

    2015-01-01

    Roč. 477, MAR 1 (2015), s. 14-24 ISSN 0376-7388 Institutional support: RVO:67985858 Keywords : composite membrane * structure * hydrocarbons pervaporation Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 5.557, year: 2015

  9. Modeling selenate adsorption behavior on oxides, clay minerals, and soils using the triple layer model

    Science.gov (United States)

    Selenate adsorption behavior was investigated on amorphous aluminum oxide, amorphous iron oxide, goethite, clay minerals: kaolinites, montmorillonites, illite, and 18 soil samples from Hawaii, and the Southwestern and the Midwestern regions of the US as a function of solution pH. Selenate adsorpti...

  10. Estimation of nocturnal CO2 and N2O soil emissions from changes in surface boundary layer mass storage

    Science.gov (United States)

    Grant, Richard H.; Omonode, Rex A.

    2018-04-01

    Annual budgets of greenhouse and other trace gases require knowledge of the emissions throughout the year. Unfortunately, emissions into the surface boundary layer during stable, calm nocturnal periods are not measurable using most micrometeorological methods due to non-stationarity and uncoupled flow. However, during nocturnal periods with very light winds, carbon dioxide (CO2) and nitrous oxide (N2O) frequently accumulate near the surface and this mass accumulation can be used to determine emissions. Gas concentrations were measured at four heights (one within and three above canopy) and turbulence was measured at three heights above a mature 2.5 m maize canopy from 23 July to 10 September 2015. Nocturnal CO2 and N2O fluxes from the canopy were determined using the accumulation of mass within a 6.3 m control volume and out the top of the control volume within the nocturnal surface boundary layer. Diffusive fluxes were estimated by flux gradient method. The total accumulative and diffusive fluxes during near-calm nights (friction velocities CO2 and 0.53 nmol m-2 s-1 N2O. Fluxes were also measured using chambers. Daily mean CO2 fluxes determined by the accumulation method were 90 to 130 % of those determined using soil chambers. Daily mean N2O fluxes determined by the accumulation method were 60 to 80 % of that determined using soil chambers. The better signal-to-noise ratios of the chamber method for CO2 over N2O, non-stationary flow, assumed Schmidt numbers, and anemometer tilt were likely contributing reasons for the differences in chambers versus accumulated nocturnal mass flux estimates. Near-surface N2O accumulative flux measurements in more homogeneous regions and with greater depth are needed to confirm the conclusion that mass accumulation can be effectively used to estimate soil emissions during nearly calm nights.

  11. Fabrication of PVDF-based blend membrane with a thin hydrophilic deposition layer and a network structure supporting layer via the thermally induced phase separation followed by non-solvent induced phase separation process

    Science.gov (United States)

    Wu, Zhiguo; Cui, Zhenyu; Li, Tianyu; Qin, Shuhao; He, Benqiao; Han, Na; Li, Jianxin

    2017-10-01

    A simple strategy of thermally induced phase separation followed by non-solvent induced phase separation (TIPS-NIPS) is reported to fabricate poly (vinylidene fluoride) (PVDF)-based blend membrane. The dissolved poly (styrene-co-maleic anhydride) (SMA) in diluent prevents the crystallization of PVDF during the cooling process and deposites on the established PVDF matrix in the later extraction. Compared with traditional coating technique, this one-step TIPS-NIPS method can not only fabricate a supporting layer with an interconnected network structure even via solid-liquid phase separation of TIPS, but also form a uniform SMA skin layer approximately as thin as 200 nm via surface deposition of NIPS. Besides the better hydrophilicity, what's interesting is that the BSA rejection ratio increases from 48% to 94% with the increase of SMA, which indicates that the separation performance has improved. This strategy can be conveniently extended to the creation of firmly thin layer, surface functionalization and structure controllability of the membrane.

  12. Development of DBD plasma actuators: The double encapsulated electrode

    Science.gov (United States)

    Erfani, Rasool; Zare-Behtash, Hossein; Hale, Craig; Kontis, Konstantinos

    2015-04-01

    Plasma actuators are electrical devices that generate a wall bounded jet without the use of any moving parts. For aerodynamic applications they can be used as flow control devices to delay separation and augment lift on a wing. The standard plasma actuator consists of a single encapsulated (ground) electrode. The aim of this project is to investigate the effect of varying the number and distribution of encapsulated electrodes in the dielectric layer. Utilising a transformer cascade, a variety of input voltages are studied for their effect. In the quiescent environment of a Faraday cage the velocity flow field is recorded using particle image velocimetry. Through understanding of the mechanisms involved in producing the wall jet and the importance of the encapsulated electrode a novel actuator design is proposed. The actuator design distributes the encapsulated electrode throughout the dielectric layer. The experiments have shown that actuators with a shallow initial encapsulated electrode induce velocities greater than the baseline case at the same voltage. Actuators with a deep initial encapsulated electrode are able to induce the highest velocities as they can operate at higher voltages without breakdown of the dielectric.

  13. Selective encapsulation by Janus particles

    Energy Technology Data Exchange (ETDEWEB)

    Li, Wei, E-mail: wel208@mrl.ucsb.edu [Materials Research Laboratory, University of California, Santa Barbara, California 93106 (United States); Ruth, Donovan; Gunton, James D. [Department of Physics, Lehigh University, Bethlehem, Pennsylvania 18015 (United States); Rickman, Jeffrey M. [Department of Physics, Lehigh University, Bethlehem, Pennsylvania 18015 (United States); Department of Materials Science and Engineering, Lehigh University, Bethlehem, Pennsylvania 18015 (United States)

    2015-06-28

    We employ Monte Carlo simulation to examine encapsulation in a system comprising Janus oblate spheroids and isotropic spheres. More specifically, the impact of variations in temperature, particle size, inter-particle interaction range, and strength is examined for a system in which the spheroids act as the encapsulating agents and the spheres as the encapsulated guests. In this picture, particle interactions are described by a quasi-square-well patch model. This study highlights the environmental adaptation and selectivity of the encapsulation system to changes in temperature and guest particle size, respectively. Moreover, we identify an important range in parameter space where encapsulation is favored, as summarized by an encapsulation map. Finally, we discuss the generalization of our results to systems having a wide range of particle geometries.

  14. Cheap Thin Film Oxygen Membranes

    DEFF Research Database (Denmark)

    2009-01-01

    The present invention provides a membrane, comprising a porous support layer a gas tight electronically and ionically conducting membrane layer and a catalyst layer, characterized in that the electronically and ionically conducting membrane layer is formed from a material having a crystallite...... structure with a crystal size of about 1 to 100 nm, and a method for producing same....

  15. Diagnosing the Sensitivity of Local Land-Atmosphere Coupling via the Soil Moisture-Boundary Layer Interaction

    Science.gov (United States)

    Santanello, Joseph A., Jr.; Peters-Lidard, Christa D.; Kumar, Sujay V.

    2011-01-01

    The inherent coupled nature of earth s energy and water cycles places significant importance on the proper representation and diagnosis of land atmosphere (LA) interactions in hydrometeorological prediction models. However, the precise nature of the soil moisture precipitation relationship at the local scale is largely determined by a series of nonlinear processes and feedbacks that are difficult to quantify. To quantify the strength of the local LA coupling (LoCo), this process chain must be considered both in full and as individual components through their relationships and sensitivities. To address this, recent modeling and diagnostic studies have been extended to 1) quantify the processes governing LoCo utilizing the thermodynamic properties of mixing diagrams, and 2) diagnose the sensitivity of coupled systems, including clouds and moist processes, to perturbations in soil moisture. This work employs NASA s Land Information System (LIS) coupled to the Weather Research and Forecasting (WRF) mesoscale model and simulations performed over the U.S. Southern Great Plains. The behavior of different planetary boundary layers (PBL) and land surface scheme couplings in LIS WRF are examined in the context of the evolution of thermodynamic quantities that link the surface soil moisture condition to the PBL regime, clouds, and precipitation. Specifically, the tendency toward saturation in the PBL is quantified by the lifting condensation level (LCL) deficit and addressed as a function of time and space. The sensitivity of the LCL deficit to the soil moisture condition is indicative of the strength of LoCo, where both positive and negative feedbacks can be identified. Overall, this methodology can be applied to any model or observations and is a crucial step toward improved evaluation and quantification of LoCo within models, particularly given the advent of next-generation satellite measurements of PBL and land surface properties along with advances in data assimilation

  16. Modeling the effects of fire severity and climate warming on active layer thickness and soil carbon storage of black spruce forests across the landscape in interior Alaska

    International Nuclear Information System (INIS)

    Genet, H; Euskirchen, E S; McGuire, A D; Barrett, K; Breen, A; Bennett, A; Rupp, T S; Johnstone, J F; Kasischke, E S; Melvin, A M; Mack, M C; Schuur, A E G; Turetsky, M R; Yuan, F

    2013-01-01

    There is a substantial amount of carbon stored in the permafrost soils of boreal forest ecosystems, where it is currently protected from decomposition. The surface organic horizons insulate the deeper soil from variations in atmospheric temperature. The removal of these insulating horizons through consumption by fire increases the vulnerability of permafrost to thaw, and the carbon stored in permafrost to decomposition. In this study we ask how warming and fire regime may influence spatial and temporal changes in active layer and carbon dynamics across a boreal forest landscape in interior Alaska. To address this question, we (1) developed and tested a predictive model of the effect of fire severity on soil organic horizons that depends on landscape-level conditions and (2) used this model to evaluate the long-term consequences of warming and changes in fire regime on active layer and soil carbon dynamics of black spruce forests across interior Alaska. The predictive model of fire severity, designed from the analysis of field observations, reproduces the effect of local topography (landform category, the slope angle and aspect and flow accumulation), weather conditions (drought index, soil moisture) and fire characteristics (day of year and size of the fire) on the reduction of the organic layer caused by fire. The integration of the fire severity model into an ecosystem process-based model allowed us to document the relative importance and interactions among local topography, fire regime and climate warming on active layer and soil carbon dynamics. Lowlands were more resistant to severe fires and climate warming, showing smaller increases in active layer thickness and soil carbon loss compared to drier flat uplands and slopes. In simulations that included the effects of both warming and fire at the regional scale, fire was primarily responsible for a reduction in organic layer thickness of 0.06 m on average by 2100 that led to an increase in active layer thickness

  17. Protein encapsulation via porous CaCO3 microparticles templating.

    Science.gov (United States)

    Volodkin, Dmitry V; Larionova, Natalia I; Sukhorukov, Gleb B

    2004-01-01

    Porous microparticles of calcium carbonate with an average diameter of 4.75 microm were prepared and used for protein encapsulation in polymer-filled microcapsules by means of electrostatic layer-by-layer assembly (ELbL). Loading of macromolecules in porous CaCO3 particles is affected by their molecular weight due to diffusion-limited permeation inside the particles and also by the affinity to the carbonate surface. Adsorption of various proteins and dextran was examined as a function of pH and was found to be dependent both on the charge of the microparticles and macromolecules. The electrostatic effect was shown to govern this interaction. This paper discusses the factors which can influence the adsorption capacity of proteins. A new way of protein encapsulation in polyelectrolyte microcapsules is proposed exploiting the porous, biocompatible, and decomposable microparticles from CaCO3. It consists of protein adsorption in the pores of the microparticles followed by ELbL of oppositely charged polyelectrolytes and further core dissolution. This resulted in formation of polyelectrolyte-filled capsules with protein incorporated in interpenetrating polyelectrolyte network. The properties of CaCO3 microparticles and capsules prepared were characterized by scanning electron microscopy, microelectrophoresis, and confocal laser scanning microscopy. Lactalbumin was encapsulated by means of the proposed technique yielding a content of 0.6 pg protein per microcapsule. Horseradish peroxidase saves 37% of activity after encapsulation. However, the thermostability of the enzyme was improved by encapsulation. The results demonstrate that porous CaCO3 microparticles can be applied as microtemplates for encapsulation of proteins into polyelectrolyte capsules at neutral pH as an optimal medium for a variety of bioactive material, which can also be encapsulated by the proposed method. Microcapsules filled with encapsulated material may find applications in the field of

  18. A proposed agglomerate model for oxygen reduction in the catalyst layer of proton exchange membrane fuel cells

    International Nuclear Information System (INIS)

    Zhang, Xiaoxian; Gao, Yuan; Ostadi, Hossein; Jiang, Kyle; Chen, Rui

    2014-01-01

    Highlights: • We developed a new agglomerate model to describe oxygen reduction reaction. • We showed how to calculate the model parameters from catalyst layer structure. • We verified the agglomerate model. - Abstract: Oxygen diffusion and reduction in the catalyst layer of PEM fuel cell is an important process in fuel cell modelling, but models able to link the reduction rate to catalyst-layer structure are lack; this paper makes such an effort. We first link the average reduction rate over the agglomerate within a catalyst layer to a probability that an oxygen molecule, which is initially on the agglomerate surface, will enter and remain in the agglomerate at any time in the absence of any electrochemical reaction. We then propose a method to directly calculate distribution function of this probability and apply it to two catalyst layers with contrasting structures. A formula is proposed to describe these calculated distribution functions, from which the agglomerate model is derived. The model has two parameters and both can be independently calculated from catalyst layer structures. We verify the model by first showing that it is an improvement and able to reproduce what the spherical model describes, and then testing it against the average oxygen reductions directly calculated from pore-scale simulations of oxygen diffusion and reaction in the two catalyst layers. The proposed model is simple, but significant as it links the average oxygen reduction to catalyst layer structures, and its two parameters can be directly calculated rather than by calibration

  19. Encapsulation of phytosterols and phytosterol esters in liposomes made with soy phospholipids by high pressure homogenization.

    Science.gov (United States)

    Wang, Fan C; Acevedo, Nuria; Marangoni, Alejandro G

    2017-11-15

    Phytosterols and phytosterol esters were encapsulated within large unilamellar liposomes prepared with soy phospholipids using a microfluidizer. The average particle diameter of these liposomal vesicles increased with increasing amounts of encapsulated phytosterols, especially with increasing free sterol content. The phytosterol content, liposomal particle size, and phytosterol encapsulation efficiency started to plateau when liposomes were prepared with MOPS buffer dispersions that contained 50 mg ml -1 soy phospholipid and more than 4% phytosterol blend, suggesting the saturation of phytosterol encapsulation. We proposed an encapsulation mechanism of free sterols and phytosterol esters in liposomes, where free sterols were mainly encapsulated within the lumen of these liposomes as crystals, and sterol esters and some free sterols were incorporated within the phospholipid bilayer of the liposomal membrane. The results from this work could provide the pharmaceutical and nutraceutical industries a practical method to produce loaded liposomes using inexpensive phospholipid mixtures for the delivery of bioactive ingredients.

  20. Effect of dissolved oxygen manipulation on diffusive emissions from NAPL-impacted low permeability soil layers.

    Science.gov (United States)

    Clifton, Lisa M; Dahlen, Paul R; Johnson, Paul C

    2014-05-06

    Aquifer physical model experiments were performed to investigate if diffusive emissions from nonaqueous phase liquid (NAPL)-impacted low-permeability layers into groundwater moving through adjacent NAPL-free high-permeability layers can be reduced by creating an aerobic biotreatment zone at the interface between the two, and if over time that leads to reduced emissions after treatment ceases. Experiments were performed in two 1.2-m long × 1.2-m high × 5.4 cm wide stainless steel tanks; each with a high-permeability sand layer overlying a low-permeability crushed granite layer containing a NAPL mixture of indane and benzene. Each tank was water-saturated with horizontal flow primarily through the sand layer. The influent water was initially deoxygenated and the emissions and concentration distributions were allowed to reach near-steady conditions. The influent dissolved oxygen (DO) level was increased stepwise to 6.5-8.5 mg/L and 17-20 mg/L, and then decreased back to deoxygenated conditions. Each condition was maintained for at least 45 days. Relative to the near-steady benzene emission at the initial deoxygenated condition, the emission was reduced by about 70% when the DO was 6.5-8.5 mg/L, 90% when the DO was 17-20 mg/L, and ultimately 60% when returning to low DO conditions. While the reductions were substantial during treatment, longer-term reductions after 120 d of elevated DO treatment, relative to an untreated condition predicted by theory, were low: 29% and 6% in Tank 1 and Tank 2, respectively. Results show a 1-2 month lag between the end of DO delivery and rebound to the final near-steady emissions level. This observation has implications for post-treatment performance monitoring sampling at field sites.

  1. Swedish encapsulation station review

    International Nuclear Information System (INIS)

    Andersson, Sven Olof; Brunzell, P.; Heibel, R.; McCarthy, J.; Pennington, C.; Rusch, C.; Varley, G.

    1998-06-01

    In the Encapsulation Station (ES) Review performed by NAC International, a number of different areas have been studied. The main objectives with the review have been to: Perform an independent review of the cost estimates for the ES presented in SKB's document 'Plan 1996'. This has been made through comparisons between the ES and BNFL's Waste Encapsulation Plant (WEP) at Sellafield as well as with the CLAB facility. Review the location of the ES (at the CLAB site or at the final repository) and its interaction with other parts of the Swedish system for spent fuel management. Review the logistics and plant capacity of the ES. Identify important safety aspects of the ES as a basis for future licensing activities. Based on NAC International's experience of casks for transport and storage of spent fuel, review the basic design of the copper/steel canister and the transport cask. This review insides design, manufacturing, handling and licensing aspects. Perform an overall comparison between the ES project and the CLAB project with the objective to identify major project risks and discuss their mitigation

  2. Swedish encapsulation station review

    Energy Technology Data Exchange (ETDEWEB)

    Andersson, Sven Olof; Brunzell, P.; He