WorldWideScience

Sample records for membrane based humidifiers

  1. Modeling of a Membrane Based Humidifier for Fuel Cell Applications Subject to End-Of-Life Conditions

    DEFF Research Database (Denmark)

    Nielsen, Mads Pagh; Olesen, Anders Christian; Menard, Alan

    2014-01-01

    applications. For instance for automotive applications and various backup power systems substituting batteries. Humidification of the inlet air of PEM fuel cell stacks is essential to obtain optimum proton conductivity. Operational humidities of the anode and cathode streams having dew points close to the fuel......Proton Exchange Membrane (PEM) Fuel Cell Stacks efficiently convert the chemical energy in hydrogen to electricity through electrochemical reactions occurring on either side of a proton conducting electrolyte. This is a promising and very robust energy conversion process which can be used in many...... cell operating temperature are required. These conditions must be met at the Beginning-Of-Life (BOL) as well as at the End-Of-Life (EOL) of the fuel cell system. This paper presents results of a numerical 1D model of the heat- and mass transport phenomena in a membrane humidifier with a Nafion...

  2. Effect of sulfonated carbon nanofiber-supported Pt on performance of Nafion {sup registered} -based self-humidifying composite membrane for proton exchange membrane fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Hung, T.F. [Department of Chemistry and Center for Nanotechnology, Chung Yuan Christian University, 200 Chung Pei Rd., Chung-Li, 32023 (China); Department of Chemistry, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei, 10617 (China); Liao, S.H.; Li, C.Y.; Chen-Yang, Y.W. [Department of Chemistry and Center for Nanotechnology, Chung Yuan Christian University, 200 Chung Pei Rd., Chung-Li, 32023 (China)

    2011-01-01

    In the present study, the Nafion {sup registered} -based self-humidifying composite membrane (N-SHCM) with sulfonated carbon nanofiber-supported Pt (s-Pt/CNF) catalyst, N-s-Pt/CNF, is successfully prepared using the solution-casting method. The scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) images of N-s-Pt/CNF indicate that s-Pt/CNF is well dispersed in the Nafion {sup registered} matrix due to the good compatibility between Nafion {sup registered} and s-Pt/CNF. Compared with those of the non-sulfonated Pt/CNF-containing N-SHCM, N-Pt/CNF, the properties of N-s-Pt/CNF, including electronic resistivity, ion-exchange capacity (IEC), water uptake, dimensional stability, and catalytic activity, significantly increase. The maximum power density of the proton exchange membrane fuel cell (PEMFC) fabricated with N-s-Pt/CNF operated at 50 C under dry H{sub 2}/O{sub 2} condition is about 921 mW cm{sup -2}, which is approximately 34% higher than that with N-Pt/CNF. (author)

  3. Internal humidifying of PEM [Proton Exchange Membrane] fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Staschewski, D [Karlsruhe Research Center (FZK), Karlsruhe (Germany). Inst. for Neutron Physics and Reactor Technics

    1996-12-01

    Hydrogen fuel cells (FC) for vehicular traction should stand out for a car-specific lightweight design. As regards PEMFC systems containing proton exchange membranes, this quality can be considerably improved by introducing porous bipolar plates which are conditioned by a water loop and deliver hot humidifying water to the adjacent membrane-electrode assembly (MEA). According to the principle of internal humidification here indicated special fuel cells based on sintered fiber and powder graphite were manufactured at FZK on a semi-technical scale. Self-made Pt/C electrodes hotpressed onto Nafion resulted in currents up to 200 A with pure oxygen as oxidant, providing the precondition for detailed studies of turnover and drainage rates within a monocell test arrangement. (author)

  4. Control-oriented model of a membrane humidifier for fuel cell applications

    International Nuclear Information System (INIS)

    Solsona, Miguel; Kunusch, Cristian; Ocampo-Martinez, Carlos

    2017-01-01

    Highlights: • A control-oriented model of a Nafion® membrane gas humidifier has been developed. • The control-oriented model has been experimentally validated. • A non-linear control strategy has been used to test its suitability for control purposes. - Abstract: Improving the humidification of polymer electrolyte membrane fuel-cells (PEMFC) is essential to optimize its performance and stability. Therefore, this paper presents an experimentally validated model of a low temperature PEMFC cathode humidifier for control/observation design purposes. A multi-input/multi-output non-linear fourth order model is derived, based on the mass and heat dynamics of circulating air. In order to validate the proposed model and methodology, experimental results are provided. Finally, a non-linear control strategy based on second order sliding mode is designed and analyzed in order to show suitability and usefulness of the approach.

  5. Mass and Heat Transfer Analysis of Membrane Humidifier with a Simple Lumped Mass Model

    International Nuclear Information System (INIS)

    Lee, Young Duk; Bae, Ho June; Ahn, Kook Young; Yu, Sang Seok; Hwang, Joon Young

    2009-01-01

    The performance of proton exchange membrane fuel cell (PEMFC) is seriously changed by the humidification condition which is intrinsic characteristics of the PEMFC. Typically, the humidification of fuel cell is carried out with internal or external humidifier. A membrane humidifier is applied to the external humidification of residential power generation fuel cell due to its convenience and high performance. In this study, a simple static model is constructed to understand the physical phenomena of the membrane humidifier in terms of geometric parameters and operating parameters. The model utilizes the concept of shell and tube heat exchanger but the model is also able to estimate the mass transport through the membrane. Model is constructed with FORTRAN under Matlab/Simulink □ environment to keep consistency with other components model which we already developed. Results shows that the humidity of wet gas and membrane thickness are critical parameters to improve the performance of the humidifier

  6. Performance analysis of a membrane humidifier containing porous metal foam as flow distributor in a PEM fuel cell system

    International Nuclear Information System (INIS)

    Afshari, Ebrahim; Baharlou Houreh, Nasser

    2014-01-01

    Highlights: • Three metal foam configurations for the membrane humidifier are introduced. • The performances of the humidifiers containing metal foam are investigated. • A 3D CFD model is developed to compare the introduced humidifiers with one another. • Using metal foam at dry side has no positive effect on the humidifier performance. - Abstract: Using metal foam as flow distributor in membrane humidifier for proton exchange membrane (PEM) fuel cell system has some unique characteristics like more water transfer, low manufacturing complexity and low cost compared to the conventional flow channel plate. Metal foam can be applied at wet side or dry side or both sides of a humidifier. The three-dimensional CFD models are developed to investigate the performance of the above mentioned meanwhile compare them with the conventional humidifier. This model consists of a set of coupled equations including conservations of mass, momentum, species and energy for all regions of the humidifier. The results indicate that with the metal foam installed at wet side and both sides, water recovery ratio and dew point at dry side outlet are more than that of the conventional humidifier, indicating a better humidifier performance; while using metal foam at dry side has no positive effect on humidifier performance. At dry side mass flow rates higher than 10 mgr/s pressure drop in humidifier containing metal foam at wet side is lower than that of the conventional humidifier. As the mass flow rate increases from 9 to 15 mgr/s humidifier containing metal foam at wet side has better performance, while at mass flow rates lower than 9 mgr/s, the humidifier containing metal foam at both sides has better performance. At dry side inlet temperatures lower than 303 K, humidifier containing metal foam at wet side has better performance and at temperatures higher than 303 K, humidifier containing metal foam at both sides has better performance

  7. 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.

  8. Humidifier disinfectants, unfinished stories

    Directory of Open Access Journals (Sweden)

    Yeyong Choi

    2016-02-01

    Full Text Available Once released into the air, humidifier disinfectants became tiny nano-size particles, and resulted in chemical bronchoalveolitis. Families had lost their most beloved members, and even some of them became broken. Based on an estimate of two million potential victims who had experienced adverse effects from the use of humidifier disinfectants, we can say that what we have observed was only the tip of the iceberg. Problems of entire airways, as well as other systemic effects, should be examined, as we know these nano-size particles can irritate cell membranes and migrate into systemic circulation. The story of humidifier disinfectant is not finished yet.

  9. Cs2.5H0.5PWO40/SiO2 as addition self-humidifying composite membrane for proton exchange membrane fuel cells

    International Nuclear Information System (INIS)

    Wang, L.; Yi, B.L.; Zhang, H.M.; Xing, D.M.

    2007-01-01

    In this paper, we first reported a novel self-humidifying composite membrane for the proton exchange membrane fuel cell (PEMFC). Cs 2.5 H 0.5 PWO 40 /SiO 2 catalyst particles were dispersed uniformly into the Nafion (registered) resin, and then Cs 2.5 H 0.5 PWO 40 -SiO 2 /Nafion composite membrane was prepared using solution-cast method. Compared with the H 3 PWO 40 (PTA) , the Cs 2.5 H 0.5 PWO 40 /SiO 2 was steady due to the substitute of H + with Cs + and the interaction between the Cs 2.5 H 0.5 PWO 40 and SiO 2 . And compared with the performance of the fuel cell with commercial Nafion (registered) NRE-212 membrane, the cell performance with the self-humidifying composite membrane was obviously improved under both humidified and dry conditions at 60 and 80 o C. The best performance under dry condition was obtained at 60 o C. The self-humidifying composite membrane could minimize membrane conductivity loss under dry conditions due to the presence of catalyst and hydrophilic Cs 2.5 H 0.5 PWO 40 /SiO 2 particles

  10. Humidifying system design of PEMFC test platform based on the mixture of dry and wet air

    Directory of Open Access Journals (Sweden)

    Tiancai Ma

    2015-01-01

    Full Text Available Based on the present humidifying system of PEMFC test platform, a novel design based on dry and wet air mixture is proposed. Key parameters are calculated, and test platform is built. Three experiments are implemented to test the performance of proposed design. Results show that the new design can meet the requirements, and realize the quick response and accurate control.

  11. Applying hot-wire anemometry to directly measure the water balance in a proton exchange membrane fuel cell for a pre-humidified hydrogen stream

    DEFF Research Database (Denmark)

    Berning, Torsten; Shakhshir, Saher Al

    2016-01-01

    In a recent publication it has been shown how the water balance in a proton exchange membrane fuel cell can be determined employing hot wire anemometry. The hot wire sensor has to be placed into the anode outlet pipe of the operating fuel cell, and the voltage signal E that is read from the senso....... Finally, it will be shown how previously developed dew point diagrams for the anode side in a fuel cell can be corrected for a humidified hydrogen inlet stream....

  12. Preparation of Stable Pt-Clay Nanocatalysts for Self-humidifying Proton Exchange Membrane Fuel Cells

    DEFF Research Database (Denmark)

    Zhang, Wenjing

    and complexity of the whole system. Therefore, we have designed a novel Pt-clay nanocatalyst and developed a Pt-clay/Nafion nanocomposite membrane to significantly enhanced proton conductivity without any external humidification. In this study, monolayer of Pt nanoparticles of diameters of 2-3 nm with a high...... crystallinity were successfully anchored onto exfoliated nanoclay surfaces using a novel chemical vapor deposition process. Chemical bonding of Pt to the oxygen on the clay surface ensured the stability of the Pt nanoparticles, and hence, no leaching of Pt particles was observed after a prolonged...

  13. Study on Air-cooled Self-humidifying PEMFC Control Method Based on Segmented Predict Negative Feedback Control

    International Nuclear Information System (INIS)

    Zhiyu, You; Tao, Xu; Zhixiang, Liu; Yun, Peng; Weirong, Cheng

    2014-01-01

    In order to obtain the optimal output performance of the air-cooled self-humidifying proton exchange membrane fuel cell (PEMFC), the operating temperature, the air flow, purge interval and some other parameters must be controlled strictly. As a key factor, the operating temperature mainly determines the optimal output performance of the fuel cell. However, some intrinsic issues such as long adjusting time, over-shoot still exist inevitably for the traditional PID temperature-controlled method in circumstances of the load variation. Consequently, output performance of PEMFC decreases because the operating temperature of the fuel cell fails to reach, and the corresponding lifetime of PEMFC is also reduced. In this study, a segmented predict negative feedback control method, based on the advance proportional control one, is proposed and verified by experiments to overcome the shortcomings of PID temperature control. The results demonstrate that the optimal output performance of PEMFC can be realized by utilizing the proposed method for temperature control due to its excellent properties, simple controlling and small over-shoot

  14. Efficiency measurement and uncertainty discussion of an electric engine powered by a ``self-breathing'' and ``self-humidified'' proton exchange membrane fuel cell

    Science.gov (United States)

    Schiavetti, Pierluigi; Del Prete, Zaccaria

    2007-08-01

    The efficiency of an automotive engine based on a "self-breathing" and "self-humidified" proton exchange membrane fuel cell stack (PEM FC) connected to a dc brushless electrical motor was measured under variable power load conditions. Experiments have been carried out on a small scale 150W engine model. After determining the fuel cell static polarization curve and the time response to power steps, the system was driven to copy on the test bench a "standard urban load cycle" and its instantaneous efficiencies were measured at an acquisition rate of 5Hz. The integral system efficiency over the entire urban load cycle, comprising the losses of the unavoidable auxiliary components of the engine, was then calculated. The fuel cell stack was operated mainly in "partial" dead-end mode, with a periodic anode flow channel purging, and one test was carried out in "pure" dead-end mode, with no anode channel purging. An uncertainty analysis of the efficiencies was carried out, taking into account either type A and type B evaluation methods, strengthening the discussion about the outcomes obtained for a system based on this novel simplified FC type. For our small scale engine we measured over the standard urban cycle, on the basis of the H2 high heating value (HHV), a tank-to-wheel integral efficiency of (18.2±0.8)%, when the fuel cell was operated with periodic flow channel purging, and of (21.5±1.3)% in complete dead-end operation mode.

  15. Fuel cell cooler-humidifier plate

    Science.gov (United States)

    Vitale, Nicholas G.; Jones, Daniel O.

    2000-01-01

    A cooler-humidifier plate for use in a proton exchange membrane (PEM) fuel cell stack assembly is provided. The cooler-humidifier plate combines functions of cooling and humidification within the fuel cell stack assembly, thereby providing a more compact structure, simpler manifolding, and reduced reject heat from the fuel cell. Coolant on the cooler side of the plate removes heat generated within the fuel cell assembly. Heat is also removed by the humidifier side of the plate for use in evaporating the humidification water. On the humidifier side of the plate, evaporating water humidifies reactant gas flowing over a moistened wick. After exiting the humidifier side of the plate, humidified reactant gas provides needed moisture to the proton exchange membranes used in the fuel cell stack assembly. The invention also provides a fuel cell plate that maximizes structural support within the fuel cell by ensuring that the ribs that form the boundaries of channels on one side of the plate have ends at locations that substantially correspond to the locations of ribs on the opposite side of the plate.

  16. Humidity control of an incubator using the microcontroller-based active humidifier system employing an ultrasonic nebulizer.

    Science.gov (United States)

    Güler, I; Burunkaya, M

    2002-01-01

    Relative humidity levels of an incubator were measured and controlled. An ultrasonic nebulizer system as an active humidifier was used to humidify the incubator environment. An integrated circuit-type humidity sensor was used to measure the humidity level of the incubator environment. Measurement and control processes were achieved by a PIC microcontroller. The high-performance and high-speed PIC provided the flexibility of the system. The developed system can be used effectively for the intensive care of newborns and/or premature babies. Since the humidifier generates an aerosol in ambient conditions, it is possible to provide the high relative humidity level for therapeutic and diagnostic purposes in medicine.

  17. Estimating retrospective exposure of household humidifier disinfectants.

    Science.gov (United States)

    Park, D U; Friesen, M C; Roh, H S; Choi, Y Y; Ahn, J J; Lim, H K; Kim, S K; Koh, D H; Jung, H J; Lee, J H; Cheong, H K; Lim, S Y; Leem, J H; Kim, Y H; Paek, D M

    2015-12-01

    We conducted a comprehensive humidifier disinfectant exposure characterization for 374 subjects with lung disease who presumed their disease was related to humidifier disinfectant use (patient group) and for 303 of their family members (family group) for an ongoing epidemiological study. We visited the homes of the registered patients to investigate disinfectant use characteristics. Probability of exposure to disinfectants was determined from the questionnaire and supporting evidence from photographs demonstrating the use of humidifier disinfectant, disinfectant purchase receipts, any residual disinfectant, and the consistency of their statements. Exposure duration was estimated as cumulative disinfectant use hours from the questionnaire. Airborne disinfectant exposure intensity (μg/m(3)) was estimated based on the disinfectant volume (ml) and frequency added to the humidifier per day, disinfectant bulk level (μg/ml), the volume of the room (m(3)) with humidifier disinfectant, and the degree of ventilation. Overall, the distribution patterns of the intensity, duration, and cumulative exposure to humidifier disinfectants for the patient group were higher than those of the family group, especially for pregnant women and patients ≤6 years old. Further study is underway to evaluate the association between the disinfectant exposures estimated here with clinically diagnosed lung disease. Retrospective exposure to household humidifier disinfectant as estimated here can be used to evaluate associations with clinically diagnosed lung disease due to the use of humidifier disinfectant in Korea. The framework, with modifications to account for dispersion and use patterns, can also be potentially adapted to assessment of other household chemical exposures. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  18. A new method for calculating number concentrations of cloud condensation nuclei based on measurements of a three-wavelength humidified nephelometer system

    Science.gov (United States)

    Tao, Jiangchuan; Zhao, Chunsheng; Kuang, Ye; Zhao, Gang; Shen, Chuanyang; Yu, Yingli; Bian, Yuxuan; Xu, Wanyun

    2018-02-01

    The number concentration of cloud condensation nuclei (CCN) plays a fundamental role in cloud physics. Instrumentations of direct measurements of CCN number concentration (NCCN) based on chamber technology are complex and costly; thus a simple way for measuring NCCN is needed. In this study, a new method for NCCN calculation based on measurements of a three-wavelength humidified nephelometer system is proposed. A three-wavelength humidified nephelometer system can measure the aerosol light-scattering coefficient (σsp) at three wavelengths and the light-scattering enhancement factor (fRH). The Ångström exponent (Å) inferred from σsp at three wavelengths provides information on mean predominate aerosol size, and hygroscopicity parameter (κ) can be calculated from the combination of fRH and Å. Given this, a lookup table that includes σsp, κ and Å is established to predict NCCN. Due to the precondition for the application, this new method is not suitable for externally mixed particles, large particles (e.g., dust and sea salt) or fresh aerosol particles. This method is validated with direct measurements of NCCN using a CCN counter on the North China Plain. Results show that relative deviations between calculated NCCN and measured NCCN are within 30 % and confirm the robustness of this method. This method enables simplerNCCN measurements because the humidified nephelometer system is easily operated and stable. Compared with the method using a CCN counter, another advantage of this newly proposed method is that it can obtain NCCN at lower supersaturations in the ambient atmosphere.

  19. Rate of humidifier and humidifier disinfectant usage in Korean children: A nationwide epidemiologic study.

    Science.gov (United States)

    Yoon, Jisun; Cho, Hyun-Ju; Lee, Eun; Choi, Yean Jung; Kim, Young-Ho; Lee, Jung Lym; Lee, Ye Jin; Hong, Soo-Jong

    2017-05-01

    In South Korea, a cluster of humidifier disinfectant-induced lung injury (HDLI) cases developed between 2006 and 2011. There are no existing reports regarding the rate of humidifier disinfectant (HD) usage in the general population of Korean children. The purpose of this study was to investigate the rate of humidifier and HD usage in the general population of Korean children. This is a general population-based birth cohort multicenter study, Panel Study of Korean Children (PSKC) from 2008, a humidifier and HD-related questionnaire administered to 1577 subjects (809 male, 768 female) in 2015 (n=1577). The questionnaire consisted of four categories (humidifier usage, HD usage, exposure duration, and type of HD brands). A total of 75.6% (1192/1577) had used a humidifier, and the rate of HD usage was found to be 31.1% (409/1316). Polyhexamethylene guanidine (PHMG), used as a disinfectant, was found to have the highest usage rate (62.0%). HD was used for less than 3 months of the entire lifetime of most of the subjects. In conclusion, approximately 30% of young Korean children were exposed to HD. PHMG-containing HD was the most commonly used. These results suggest that a nationwide epidemiologic investigation is needed urgently, and children exposed to HD should be investigated regarding their status of lung injury, including a pulmonary function test. Moreover, a long-term follow-up period may be required to evaluate HD usage-associated lung injury. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Design of Polymer-Coated Multi-Walled Carbon Nanotube/Carbon Black-based Fuel Cell Catalysts with High Durability and Performance Under Non-humidified Condition

    International Nuclear Information System (INIS)

    Yang, Zehui; Berber, Mohamed R.; Nakashima, Naotoshi

    2015-01-01

    To realize a high catalyst utilization, better fuel cell performance and durability as well as low production cost, an efficient design strategy of the catalyst layer that can improve both the oxygen accessibility and structure stability is highly required. Here, we describe the preparation of fuel cell electrocatalysts with an efficient fuel cell performance and better stability based on hybrids of multi-walled carbon nanotubes (MWNTs) and carbon black (CB) which were wrapped by a proton conducting polymer, poly[2,2′-(2,6-pyridine)-5,5′-bibenzimidazole], before deposition of the platinum (Pt) metal catalyst. The catalyst mass activity after feeding only 10%-MWNTs to CB increased by 1.5 and 2 times than those of the MWNTs-based- and CB-based catalysts, respectively. The results also demonstrated that 90 wt% of the MWNTs in the catalyst layer allows it to be replaced by CB without any significant change in its durability and performance under 120 °C and non-humidified condition

  1. Smart membranes for monitoring membrane based desalination processes

    KAUST Repository

    Laleg-Kirati, Taous-Meriem; Karam, Ayman M.

    2017-01-01

    Various examples are related to smart membranes for monitoring membrane based process such as, e.g., membrane distillation processes. In one example, a membrane, includes a porous surface and a plurality of sensors (e.g., temperature, flow and

  2. Experimental study on the start-up with dry gases from normal cell temperatures in self-humidified proton exchange membrane fuel cells

    International Nuclear Information System (INIS)

    Kong, Im Mo; Jung, Aeri; Kim, Beom Jun; Baik, Kyung Don; Kim, Min Soo

    2015-01-01

    In this study, the start-up characteristics of PEMFCs (proton exchange membrane fuel cells) was investigated with dry gases from normal cell temperatures above 0 °C. Firstly, the effects of flow arrangements (co-flow and counter-flow) were evaluated at a starting cell temperature of 25 °C. Then, the start-up was successful in both arrangements, but it showed better performance with counter-flow. In addition, the hydrogen concentration was measured and it showed that hydrogen crossover contributes to the membrane hydration and the first phase of dry start-up. However, although the cell temperature rose above 45 °C after start-up form 25 °C with counter-flow arrangement, the restart-up after shut-down failed at a starting cell temperature of 45 °C regardless of flow arrangements. Considering the needs of restart-up, the available starting cell temperature should be improved. For this, after first sub-step of start-up process, relatively low flow rates were maintained to retain produced water without purge so that the membrane can be hydrated sufficiently. With this modified process, denominated as WSP (water storage process) in this study, the dry start-up became successful at a starting cell temperature of 45 °C and the cell performance was remarkably improved especially with counter-flow arrangement. - Highlights: • Start-up with dry gases from normal cell temperatures was investigated. • Counter-flow arrangement showed better performance over co-flow arrangement. • Water is produced by hydrogen crossover and its direct reaction with oxygen at cathode side. • It prevents the membrane dehydration and helps the start-up during the first phase of the process. • Available starting cell temperature and cell performance could be improved with WSP.

  3. Brief report: sound output of infant humidifiers.

    Science.gov (United States)

    Royer, Allison K; Wilson, Paul F; Royer, Mark C; Miyamoto, Richard T

    2015-06-01

    The sound pressure levels (SPLs) of common infant humidifiers were determined to identify the likely sound exposure to infants and young children. This primary investigative research study was completed at a tertiary-level academic medical center otolaryngology and audiology laboratory. Five commercially available humidifiers were obtained from brick-and-mortar infant supply stores. Sound levels were measured at 20-, 100-, and 150-cm distances at all available humidifier settings. Two of 5 (40%) humidifiers tested had SPL readings greater than the recommended hospital infant nursery levels (50 dB) at distances up to 100 cm. In this preliminary study, it was demonstrated that humidifiers marketed for infant nurseries may produce appreciably high decibel levels. Further characterization of the effect of humidifier design on SPLs and further elucidation of ambient sound levels associated with hearing risk are necessary before definitive conclusions and recommendations can be made. © American Academy of Otolaryngology—Head and Neck Surgery Foundation 2015.

  4. Process for humidifying a gaseous fuel stream

    International Nuclear Information System (INIS)

    Sederquist, R. A.

    1985-01-01

    A fuel gas stream for a fuel cell is humidified by a recirculating hot liquid water stream using the heat of condensation from the humidified stream as the heat to vaporize the liquid water. Humidification is accomplished by directly contacting the liquid water with the dry gas stream in a saturator to evaporate a small portion of water. The recirculating liquid water is reheated by direct contact with the humidified gas stream in a condenser, wherein water is condensed into the liquid stream. Between the steps of humidifying and condensing water from the gas stream it passes through the fuel cell and additional water, in the form of steam, is added thereto

  5. Sol-Gel Based Polybenzimidazole Membranes for Hydrogen Pumping Devices

    Energy Technology Data Exchange (ETDEWEB)

    Benicewicz, Brian C. [Rensselaer Polytechnic Institute, Troy, NY (United States). Department of Chemistry and Chemical Biology; Eisman, Glenn A. [Rensselaer Polytechnic Institute, Troy, NY (United States). Department of Materials Science and Engineering; Kumar, S. K. [Columbia Univ., New York, NY (United States). Department of Chemical Engineering; Greenbaum, S. G. [Hunter College, New York, NY (United States). Department of Physics

    2014-02-26

    Electrochemical hydrogen pumping using a high temperature (>100°C) PBI membrane was demonstrated under non-humidified and humidified conditions at ambient pressures. Relatively low voltages were required to operate the pump over a wide range of hydrogen flow rates. The advantages of the high temperature capability were shown by operating the pump on reformate feed gas mixtures containing various amounts of CO and CO2. Gas purity measurements on the cathode gas product were conducted and significant reductions in gas impurities were detected. The applicability of the PBI membrane for electrochemical hydrogen pumping and its durability under typical operating conditions was established with tests that lasted for nearly 4000 hours.

  6. Effect of chloride impurities on the performance and durability of polybenzimidazole-based high temperature proton exchange membrane fuel cells

    DEFF Research Database (Denmark)

    Ali, Syed Talat; Li, Qingfeng; Pan, Chao

    2011-01-01

    The effect of chloride as an air impurity and as a catalyst contaminant on the performance and durability of polybenzimidazole (PBI)-based high temperature proton exchange membrane fuel cell (HT-PEMFC) was studied. The ion chromatographic analysis reveals the existence of chloride contaminations....... The performance loss was recovered when switching from the HCl solution back to pure water in the air humidifier. Under an accelerated aging performance test conducted through potential cycling between 0.9 V and 1.2 V, the PBI-based fuel cell initially containing 0.5 NaCl mg cm−2 on the cathode catalyst layer...

  7. Smart membranes for monitoring membrane based desalination processes

    KAUST Repository

    Laleg-Kirati, Taous-Meriem

    2017-10-12

    Various examples are related to smart membranes for monitoring membrane based process such as, e.g., membrane distillation processes. In one example, a membrane, includes a porous surface and a plurality of sensors (e.g., temperature, flow and/or impedance sensors) mounted on the porous surface. In another example, a membrane distillation (MD) process includes the membrane. Processing circuitry can be configured to monitor outputs of the plurality of sensors. The monitored outputs can be used to determine membrane degradation, membrane fouling, or to provide an indication of membrane replacement or cleaning. The sensors can also provide temperatures or temperature differentials across the porous surface, which can be used to improve modeling or control the MD process.

  8. Humidifiers: Air Moisture Eases Skin, Breathing Symptoms

    Science.gov (United States)

    ... create deposits inside your humidifier that promote bacterial growth. And, when released into the air, these minerals often appear as white dust on your furniture. You may also breathe in some minerals that ...

  9. Adverse health effects of humidifier disinfectants in Korea: lung toxicity of polyhexamethylene guanidine phosphate.

    Science.gov (United States)

    Kim, Ha-Ryong; Hwang, Gi-Wook; Naganuma, Akira; Chung, Kyu-Hyuck

    2016-01-01

    Exposure to humidifier disinfectants was identified in 2011 as the potential cause of an outbreak of lung disease in Korea. It is estimated that over 8 million people have been exposed to humidifier disinfectants-chemicals added to the water used in humidifiers to prevent the growth of microorganisms-since their commercial introduction. The primary component of humidifier disinfectant products involved was polyhexamethylene guanidine phosphate (PHMG-P), a guanidine-based antimicrobial agent. Lesions observed in the lungs of patients were similar to those observed in laboratory animals exposed to PHMG-P. In this review, we outline the physicochemical and toxicological properties of PHMG-P, and introduce a putative mechanism for its lung toxicity based in large part on research findings to date.

  10. Humidification during laparoscopic surgery: overview of the clinical benefits of using humidified gas during laparoscopic surgery.

    Science.gov (United States)

    Binda, Maria Mercedes

    2015-11-01

    The peritoneum is the serous membrane that covers the abdominal cavity and most of the intra-abdominal organs. It is a very delicate layer highly susceptible to damage and it is not designed to cope with variable conditions such as the dry and cold carbon dioxide (CO2) during laparoscopic surgery. The aim of this review was to evaluate the effects caused by insufflating dry and cold gas into the abdominal cavity after laparoscopic surgery. A literature search using the Pubmed was carried out. Articles identified focused on the key issues of laparoscopy, peritoneum, morphology, pneumoperitoneum, humidity, body temperature, pain, recovery time, post-operative adhesions and lens fogging. Insufflating dry and cold CO2 into the abdomen causes peritoneal damage, post-operative pain, hypothermia and post-operative adhesions. Using humidified and warm gas prevents pain after surgery. With regard to hypothermia due to desiccation, it can be fully prevented using humidified and warm gas. Results relating to the patient recovery are still controversial. The use of humidified and warm insufflation gas offers a significant clinical benefit to the patient, creating a more physiologic peritoneal environment and reducing the post-operative pain and hypothermia. In animal models, although humidified and warm gas reduces post-operative adhesions, humidified gas at 32 °C reduced them even more. It is clear that humidified gas should be used during laparoscopic surgery; however, a question remains unanswered: to achieve even greater clinical benefit to the patient, at what temperature should the humidified gas be when insufflated into the abdomen? More clinical trials should be performed to resolve this query.

  11. Influence of Silica/Sulfonated Polyether-Ether Ketone as Polymer Electrolyte Membrane for Hydrogen Fueled Proton Exchange Membrane Fuel Cells

    Directory of Open Access Journals (Sweden)

    Sri Handayani

    2011-12-01

    Full Text Available The operation of non-humidified condition of proton exchange membrane fuel cell (PEMFC using composite sPEEK-silica membrane is reported. Sulfonated membrane of PEEK is known as hydrocarbon polyelectrolyte membrane for PEMFC and direct methanol fuel cell (DMFC. The state of the art of fuel cells is based on the perluorosulfonic acid membrane (Nafion. Nafion has been the most used in both PEMFC and DMFC due to good performance although in low humidified condition showed poor current density. Here we reported the effect of silica in hydrocarbon sPEEK membrane that contributes for a better water management system inside the cell, and showed 0.16 W/cm2 of power density which is 78% higher than that of non-silica modified [Keywords: composite membrane, polyether-ether ketone, silica, proton exchange membrane fuel cell].

  12. Energy conservation employing membrane-based technology

    International Nuclear Information System (INIS)

    Narayanan, C.M.

    1993-01-01

    Membranes based processes, if properly adapted to industrial processes have good potential with regard to optimisation and economisation of energy consumption. The specific benefits of MBT (membrane based technology) as an energy conservation methodology are highlighted. (author). 6 refs

  13. [Air humidifier--benefit or risk?].

    Science.gov (United States)

    Fidler, A H

    1989-12-01

    Indoor air pollution has become an issue of growing importance for the scientific community. A recent publication of a report of the US Environmental Protection Agency (EPA) showed evidence that portable ultrasonic humidifiers may play a significant role as health hazards as far as indoor air pollution with heavy metal particles is concerned. Especially if the manufacturers' guidelines are not followed strictly and the device is operated with tap water, indoor particle concentrations may reach up to 50 times US outdoor standards for toxic particle concentration. This paper highlights potential risks and benefits of various types of humidifiers, both in private and hospital settings, emphasizing that risks of air humidification in certain situations might outweigh anticipated benefits. The health policy implication of these findings should lead to a more critical application of air humidification in the health care environment and in addition to that, promote better information of the customer about safe operation and useful indications of such devices.

  14. Robust High Performance Aquaporin based Biomimetic Membranes

    DEFF Research Database (Denmark)

    Helix Nielsen, Claus; Zhao, Yichun; Qiu, C.

    2013-01-01

    on top of a support membrane. Control membranes, either without aquaporins or with the inactive AqpZ R189A mutant aquaporin served as controls. The separation performance of the membranes was evaluated by cross-flow forward osmosis (FO) and reverse osmosis (RO) tests. In RO the ABM achieved a water......Aquaporins are water channel proteins with high water permeability and solute rejection, which makes them promising for preparing high-performance biomimetic membranes. Despite the growing interest in aquaporin-based biomimetic membranes (ABMs), it is challenging to produce robust and defect...... permeability of ~ 4 L/(m2 h bar) with a NaCl rejection > 97% at an applied hydraulic pressure of 5 bar. The water permeability was ~40% higher compared to a commercial brackish water RO membrane (BW30) and an order of magnitude higher compared to a seawater RO membrane (SW30HR). In FO, the ABMs had > 90...

  15. Preparation and proton conductivity of composite membranes based on sulfonated poly(phenylene oxide) and benzimidazole

    International Nuclear Information System (INIS)

    Liu Yifeng; Yu Qinchun; Wu Yihua

    2007-01-01

    The Bronsted acid-base composite membrane was prepared by entrapping benzimidazole in sulfonated poly(phenylene oxide) by tuning the doping ratios. Their thermal stability, dynamic mechanical properties and proton conductivity were investigated under the conditions for intermediate temperature proton exchange membrane (PEM) fuel cell operation. In addition, investigation of activation energies of the SPPO-xBnIm at different relative humidity was also performed. TG-DTA curves reveal these SPPO-xBnIm composite materials had the high thermal stability. The proton conductivity of SPPO-xBnIm composite material increased with the temperature, and the highest proton conductivity of SPPO-xBnIm composite materials was found to be 8.93 x 10 -4 S/cm at 200 deg. C under 35% relative humidity (RH) with a 'doping rate' where x = 2. The SPPO-2BnIm composite membrane show higher storage moduli and loss moduli than SPPO. Tests in a hydrogen-air laboratory cell demonstrate the applicability of SPPO-2BnIm in PEMFCs at intermediate temperature under non-humidified conditions

  16. Biosensors Based on Ultrathin Film Composite Membranes

    Science.gov (United States)

    1994-01-25

    composite membranes should have a number C •’ of potential advantages including fast response time, simplicity of construction, and applicability to a number...The support membrane for the ultrathin film composite was an Anopore ( Alltech Associates) microporous alumina filter, these membranes are 55 Pm thick...constant 02 concentration in this solution. Finally, one of the most important potential advantage of a sensor based on an ultrathin film composite

  17. Cyanex based uranyl sensitive polymeric membrane electrodes.

    Science.gov (United States)

    Badr, Ibrahim H A; Zidan, W I; Akl, Z F

    2014-01-01

    Novel uranyl selective polymeric membrane electrodes were prepared using three different low-cost and commercially available Cyanex extractants namely, bis(2,4,4-trimethylpentyl) phosphinic acid [L1], bis(2,4,4-trimethylpentyl) monothiophosphinic acid [L2] and bis(2,4,4-trimethylpentyl) dithiophosphinic acid [L3]. Optimization and performance characteristics of the developed Cyanex based polymer membrane electrodes were determined. The influence of membrane composition (e.g., amount and type of ionic sites, as well as type of plasticizer) on potentiometric responses of the prepared membrane electrodes was studied. Optimized Cyanex-based membrane electrodes exhibited Nernstian responses for UO₂(2+) ion over wide concentration ranges with fast response times. The optimized membrane electrodes based on L1, L2 and L3 exhibited Nernstian responses towards uranyl ion with slopes of 29.4, 28.0 and 29.3 mV decade(-1), respectively. The optimized membrane electrodes based on L1-L3 showed detection limits of 8.3 × 10(-5), 3.0 × 10(-5) and 3.3 × 10(-6) mol L(-1), respectively. The selectivity studies showed that the optimized membrane electrodes exhibited high selectivity towards UO₂(2+) ion over large number of other cations. Membrane electrodes based on L3 exhibited superior potentiometric response characteristics compared to those based on L1 and L2 (e.g., widest linear range and lowest detection limit). The analytical utility of uranyl membrane electrodes formulated with Cyanex extractant L3 was demonstrated by the analysis of uranyl ion in different real samples for nuclear safeguards verification purposes. The results obtained using direct potentiometry and flow-injection methods were compared with those measured using the standard UV-visible and inductively coupled plasma spectroscopic methods. © 2013 Published by Elsevier B.V.

  18. Ceria Based Composite Membranes for Oxygen Separation

    DEFF Research Database (Denmark)

    Gurauskis, Jonas; Ovtar, Simona; Kaiser, Andreas

    2014-01-01

    Mixed ionic-electronic conducting membranes for oxygen gas separation are attracting a lot of interest due to their promising potential for the pure oxygen and the syngas production. Apart from the need for a sufficiently high oxygen permeation fluxes, the prolonged stability of these membranes...... under the large oxygen potential gradients at elevated temperatures is decisive for the future applications. The gadolinium doped cerium oxide (CGO) based composite membranes are considered as promising candidates due to inherent stability of CGO phase. The CGO matrix is a main oxygen ion transporter......; meanwhile the primary role of a secondary phase in this membrane is to compensate the low electronic conductivity of matrix at intended functioning conditions. In this work thin film (15-20 μm) composite membranes based on CGO matrix and LSF electronic conducting phase were fabricated and evaluated...

  19. Microporous Silica Based Membranes for Desalination

    Directory of Open Access Journals (Sweden)

    João C. Diniz da Costa

    2012-09-01

    Full Text Available This review provides a global overview of microporous silica based membranes for desalination via pervaporation with a focus on membrane synthesis and processing, transport mechanisms and current state of the art membrane performance. Most importantly, the recent development and novel concepts for improving the hydro-stability and separating performance of silica membranes for desalination are critically examined. Research into silica based membranes for desalination has focussed on three primary methods for improving the hydro-stability. These include incorporating carbon templates into the microporous silica both as surfactants and hybrid organic-inorganic structures and incorporation of metal oxide nanoparticles into the silica matrix. The literature examined identified that only metal oxide silica membranes have demonstrated high salt rejections under a variety of feed concentrations, reasonable fluxes and unaltered performance over long-term operation. As this is an embryonic field of research several target areas for researchers were discussed including further improvement of the membrane materials, but also regarding the necessity of integrating waste or solar heat sources into the final process design to ensure cost competitiveness with conventional reverse osmosis processes.

  20. Composite Membranes Based on Polyether Sulfone

    Directory of Open Access Journals (Sweden)

    A. Soroush

    2010-12-01

    Full Text Available The role of polymeric additives such as PVP and PEG is studied with respect to the morphology of PES porous layer as a sublayer of nanofiltration composite membranes based on PES/PA. Results show that by phase inversionprocess of quaternary systems comprised of four components of polymer/solvent/non-solvent/additive and the diffusion of intertwined polymers some changes occur in membrane morphology with changes in their concentration. With addition of PVP, tear-like pores, finger-like and channel-like morphology change to enlarged channel cavities and by adding more PVP, membrane morphology changes further and spongy regions are extended in the membrane. Presence of PEG in casting solution delayed the precipitation time. By adding PEG, the solution viscosity is increased which is followed by decreases in diffusion rates of solvent/non-solvent in coagulation bath.Therefore, membrane morphology shifts to small pores and spongier region. Another effect of increased PEG content would be deformed PA layer formation in PES sublayer which affects membrane performance. However, PVP as an additive does not change membrane salt rejection very much while it leads to higher fluxes. A membrane with 2.5 percent PVP would perform by 40 percent flux increases, while a membrane with 5% PVP shows flux reductions even below the initial value. Contrary to PVP, the PEG content of 20 percent leads to 4 folds flux increases and in a membrane with 50 percent PEG, there is a flux increase by 7 folds and drop in salt rejection occurs by 50 percent and 70 percent, respectively.

  1. Controlling fuel crossover and hydration in ultrathin proton exchange membrane-based fuel cells using Pt-nanosheet catalysts

    DEFF Research Database (Denmark)

    Wang, Rujie; Zhang, Wenjing (Angela); He, Gaohong

    2014-01-01

    and provided in situ hydration inside Nafion membranes to maintain their proton conductivity level. Furthermore, LDH nanosheets reinforced the Nafion membranes, with 181% improvement in tensile modulus and 166% improvement in yield strength. In a hydrogen fuel cell running with dry fuel, the membrane......An ultra-thin proton exchange membrane with Pt-nanosheet catalysts was designed for a self-humidifying fuel cell running on H2 and O2. In this design, an ultra-thin Nafion membrane was used to reduce ohmic resistance. Pt nanocatalysts were uniformly anchored on exfoliated, layered double hydroxide...

  2. Introduction to solid supported membrane based electrophysiology.

    Science.gov (United States)

    Bazzone, Andre; Costa, Wagner Steuer; Braner, Markus; Călinescu, Octavian; Hatahet, Lina; Fendler, Klaus

    2013-05-11

    The electrophysiological method we present is based on a solid supported membrane (SSM) composed of an octadecanethiol layer chemisorbed on a gold coated sensor chip and a phosphatidylcholine monolayer on top. This assembly is mounted into a cuvette system containing the reference electrode, a chlorinated silver wire. After adsorption of membrane fragments or proteoliposomes containing the membrane protein of interest, a fast solution exchange is used to induce the transport activity of the membrane protein. In the single solution exchange protocol two solutions, one non-activating and one activating solution, are needed. The flow is controlled by pressurized air and a valve and tubing system within a faraday cage. The kinetics of the electrogenic transport activity is obtained via capacitive coupling between the SSM and the proteoliposomes or membrane fragments. The method, therefore, yields only transient currents. The peak current represents the stationary transport activity. The time dependent transporter currents can be reconstructed by circuit analysis. This method is especially suited for prokaryotic transporters or eukaryotic transporters from intracellular membranes, which cannot be investigated by patch clamp or voltage clamp methods.

  3. Optimization of humidifying procedure in controlled environment for ...

    African Journals Online (AJOL)

    hp

    2016-11-09

    Nov 9, 2016 ... humidifying treatment had influenced the mushroom growth in ..... small water which is heavier than vapour and condense on floor very .... Indoor Mushroom Cultivation of Grey Oyster (Pleurotus pulmonarius) by Different ...

  4. Comparison of Active and Passive Humidifiers on Mechanical Ventilation

    Directory of Open Access Journals (Sweden)

    H. Dilek Mersin Özcanoğlu

    2010-12-01

    Full Text Available Objective: To research the effectiveness on humidifying, respiratory mechanics, bacterial colonization and infection rates of continuous usage for 96 hours of active and passive humidifiers which are used for heating and moisturizing the inspired gases in patients under mechanical ventilation. Materials and Methods: Adult patients who are expected to support at least 4 days under mechanical ventilation, excluding patients with primary lung disease and sepsis, are included in the research. Patients are separated in two groups as a passive humidifier group (heat moisture exchange filter (n=16 and an active humidifier group (n=14. In passive humidifier group, humidifier is used continuously for 96 hours without change. In active humidifier group moisturizing is obtained by using sterile distilled water in heated humidifier. Patients whose demographic characteristics were recorded and first 24 hour APACHE II scores were calculated, were taking chest X-Ray’s daily. Respiratory mechanics measurements were recorded twice a day which were watched in Servo300A ventilators respiratory mechanics monitor, in patients under volume controlled ventilation. The amount of moisture and liquidity of the secretion in endotracheal tube were recorded and scored visually. The endotracheal aspiration samples at the beginning and at the end of 96th hour and respiratory circuits ventilator side sample taken at 96th hour were studied microbiologically. Cultures and colonial counts were studied at Cerrahpasa Medical Faculty Microbiology Laboratory. Results: There were no significant difference in two groups by demographic data, APACHE II scores and illness diagnoses. In passive humidifier group, respiratory mechanics showed no significant difference between the beginning and the 4th day (p>0.05. In active humidifier group when MAP, PEEPtot, EEF, Rins, Rexp values showed no significant difference between the beginning and the 4th day but PIP values showed significant

  5. HIGH PERFORMANCE CERIA BASED OXYGEN MEMBRANE

    DEFF Research Database (Denmark)

    2014-01-01

    The invention describes a new class of highly stable mixed conducting materials based on acceptor doped cerium oxide (CeO2-8 ) in which the limiting electronic conductivity is significantly enhanced by co-doping with a second element or co- dopant, such as Nb, W and Zn, so that cerium and the co......-dopant have an ionic size ratio between 0.5 and 1. These materials can thereby improve the performance and extend the range of operating conditions of oxygen permeation membranes (OPM) for different high temperature membrane reactor applications. The invention also relates to the manufacturing of supported...

  6. Nanostructured Polysulfone-Based Block Copolymer Membranes

    KAUST Repository

    Xie, Yihui

    2016-05-01

    The aim of this work is to fabricate nanostructured membranes from polysulfone-based block copolymers through self-assembly and non-solvent induced phase separation. Block copolymers containing polysulfone are novel materials for this purpose providing better mechanical and thermal stability to membranes than polystyrene-based copolymers, which have been exclusively used now. Firstly, we synthesized a triblock copolymer, poly(tert-butyl acrylate)-b-polsulfone-b-poly(tert-butyl acrylate) through polycondensation and reversible addition-fragmentation chain-transfer polymerization. The obtained membrane has a highly porous interconnected skin layer composed of elongated micelles with a flower-like arrangement, on top of the graded finger-like macrovoids. Membrane surface hydrolysis was carried out in a combination with metal complexation to obtain metal-chelated membranes. The copper-containing membrane showed improved antibacterial capability. Secondly, a poly(acrylic acid)-b-polysulfone-b-poly(acrylic acid) triblock copolymer obtained by hydrolyzing poly(tert-butyl acrylate)-b-polsulfone-b-poly(tert-butyl acrylate) formed a thin film with cylindrical poly(acrylic acid) microdomains in polysulfone matrix through thermal annealing. A phase inversion membrane was prepared from the same polymer via self-assembly and chelation-assisted non-solvent induced phase separation. The spherical micelles pre-formed in a selective solvent mixture packed into an ordered lattice in aid of metal-poly(acrylic acid) complexation. The space between micelles was filled with poly(acrylic acid)-metal complexes acting as potential water channels. The silver0 nanoparticle-decorated membrane was obtained by surface reduction, having three distinct layers with different particle sizes. Other amphiphilic copolymers containing polysulfone and water-soluble segments such as poly(ethylene glycol) and poly(N-isopropylacrylamide) were also synthesized through coupling reaction and copper0-mediated

  7. Humidity in air during and after humidifying incidents in three different houses

    DEFF Research Database (Denmark)

    Gunnarsen, Lars; Logadottir, Asta; Afshari, Alireza

    2009-01-01

    in the house and areas of main inner surface structures. The ability of the houses to absorb water in their structures after these experimentally created humidifying incidents was assessed based on mathematical models. Moisture absorption was most significant in the old masonry house during the first four...... hours after the steam was added. After this period the modern masonry house, with the slowly reacting concrete, had the highest absorption. At all times the least absorption was seen in the wooden house....

  8. EXPERIMENTAL STUDY OF CENTRIFUGAL HUMIDIFIER FITTED IN AN INDUSTRIAL SHED LOCATED IN TROPICAL CLIMATES

    Directory of Open Access Journals (Sweden)

    K SENTHILKUMAR

    2011-01-01

    Full Text Available An evaporative cooling system based on centrifugal humidification technique is proposed for large industrial spaces. In this system, the evaporation rate is improved by splitting the water into fine micronisers by impinging it onto the stationery strips. The various parameters influencing the rate of evaporation are identified. The effect of mass flow rate of water, disc speed and mass flow rate of air on space cooling and humidifier efficiency is studied experimentally and plotted with respect to time. The studies indicate that medium mass flow rate of water, higher disc speed and medium mass flow rate of air are preferable in reducing the dry bulb temperature of room and for increasing humidifier efficiency.

  9. A general model for membrane-based separation processes

    DEFF Research Database (Denmark)

    Soni, Vipasha; Abildskov, Jens; Jonsson, Gunnar Eigil

    2009-01-01

    behaviour will play an important role. In this paper, modelling of membrane-based processes for separation of gas and liquid mixtures are considered. Two general models, one for membrane-based liquid separation processes (with phase change) and another for membrane-based gas separation are presented....... The separation processes covered are: membrane-based gas separation processes, pervaporation and various types of membrane distillation processes. The specific model for each type of membrane-based process is generated from the two general models by applying the specific system descriptions and the corresponding...

  10. New Developments in Membrane-Based Chemical Separations

    National Research Council Canada - National Science Library

    Jirage, Kshama

    1998-01-01

    Membrane based chemical separations is an emerging field of research. This is because membrane-based separations are potentially less energy intensive and more cost effective than competing separation methods...

  11. Metal–organic frameworks based membranes for liquid separation

    KAUST Repository

    Li, Xin; Liu, Yuxin; Wang, Jing; Gascon, Jorge; Li, Jiansheng; Van der Bruggen, Bart

    2017-01-01

    , the field of MOF-based membranes for liquid separation is highlighted in this review. The criteria for judicious selection of MOFs in fabricating MOF-based membranes are given. Special attention is paid to rational design strategies for MOF-based membranes

  12. Analysis of genomic responses in a rat lung model treated with a humidifier sterilizer containing polyhexamethyleneguanidine phosphate.

    Science.gov (United States)

    Kim, Min-Seok; Jeong, Seok Won; Choi, Seong-Jin; Han, Jin-Young; Kim, Sung-Hwan; Yoon, Seokjoo; Oh, Jung-Hwa; Lee, Kyuhong

    2017-02-15

    The antimicrobial biocide polyhexamethyleneguanidine (PHMG) phosphate is the main ingredient in the commercially available humidifier disinfectant. PHMG phosphate-based humidifier disinfectants can cause pulmonary fibrosis and induce inflammatory and fibrotic responses both in vivo and in vitro. However, toxicological mechanisms including genomic alterations induced by inhalation exposure to PHMG phosphate have not been elucidated. Therefore, this study evaluated the toxicological effects of the PHMG phosphate-containing humidifier disinfectant. We used DNA microarray to identify global gene expression changes in rats treated with PHMG phosphate-containing humidifier disinfectant for 4 weeks and 10 weeks. Functional significance of differentially expressed genes (DEGs) was estimated by gene ontology (GO) analysis. Four weeks post-exposure, 320 and 392 DEGs were identified in female and male rats, respectively (>2-fold, pPHMG phosphate exposure. In addition, 21 genes were upregulated and 4 genes were downregulated in response to PHMG phosphate in a time-dependent manner. Thus, we predict that changes in genomic responses could be a significant molecular mechanism underlying PHMG phosphate toxicity. Further studies are required to determine the detailed mechanism of PHMG phosphate-induced pulmonary toxicity. Copyright © 2016. Published by Elsevier B.V.

  13. Fabrication and Characterisation of Membrane-Based Gold Electrodes

    DEFF Research Database (Denmark)

    Bakmand, Tanya; Kwasny, Dorota; Dimaki, Maria

    2015-01-01

    This work presents a versatile, membrane based electrochemical sensor with thin film electrodes fabricated through Ebeam evaporation directly on porous materials (membranes). Here, the fabrication of the electrodes is described along with possible methods for integration in fluidic systems...

  14. Optimization of humidifying procedure in controlled environment for ...

    African Journals Online (AJOL)

    This study investigated mushroom cultivation in controlled indoor environment. For this, the environmental factors including humidity and temperature were controlled by humidifier and ventilation. Four ventilations were installed on tops to bring the air from inside to outside and four small ventilations were installed on side ...

  15. Nationwide Study of Humidifier Disinfectant Lung Injury in South Korea, 1994-2011. Incidence and Dose-Response Relationships.

    Science.gov (United States)

    Paek, Domyung; Koh, Younsuck; Park, Dong-Uk; Cheong, Hae-Kwan; Do, Kyung-Hyun; Lim, Chae-Man; Hong, Soo-Jong; Kim, Yong-Hwa; Leem, Jong-Han; Chung, Kyu Hyuck; Choi, Ye-Yong; Lee, Jong-Hyeon; Lim, Sin-Ye; Chung, Eun-Hee; Cho, Young Ah; Chae, Eun Jin; Joh, Joon-Sung; Yoon, Yup; Lee, Kyu-Hong; Choi, Bo Youl; Gwack, Jin

    2015-12-01

    Humidifier disinfectant lung injury is an acute lung disease attributed to recurrent inhalation of certain disinfectant aerosols emitted from room humidifiers. An outbreak of this toxic lung injury occurred in South Korea from 1995 until all humidifier disinfectant products were recalled from the consumer market by the government in 2011. A nationwide study was conducted to ascertain and classify all potential cases of humidifier disinfectant lung injury in Korea and to assess dose-response relationships. By several mechanisms, clinicians and the general public were invited to report all suspected cases of humidifier disinfectant lung injury to public health officials in South Korea. A committee was convened to define diagnostic criteria based on pathologic, radiologic, and clinical findings for index cases, combined with assessment of environmental exposure to humidifier disinfectants. Clinical review and environmental assessments were performed and later combined to determine overall likelihood of disease for each study participant, classified as definite, probable, possible, or unlikely. Survival time from exposure to onset of symptoms was analyzed to assess dose-response relationships. Three broad categories of risk factors were examined: (1) biological susceptibility, (2) temporal cycle of exposure and recovery, and (3) spatial conditions and density of disinfectant. Of 374 possible cases identified and reviewed, 329 were unanimously classified by the diagnostic committee, as follows: 117 definite, 34 probable, 38 possible and 140 unlikely cases. A total of 62 individuals with definite or probable disease died. Risk factors examined for polyhexamethyleneguanidine phosphate exposure that were found to be significant in shortening survival included age 4 years or younger at onset, use of disinfectant for 7 days per week, airborne density of 800 μg/m(3) or more of disinfectant, and daily exposure 11 or more hours in duration. Dose-response analysis indicated

  16. New ETFE-based membrane for direct methanol fuel cell

    International Nuclear Information System (INIS)

    Saarinen, V.; Kallio, T.; Paronen, M.; Tikkanen, P.; Rauhala, E.; Kontturi, K.

    2005-01-01

    The investigated membranes are based on 35-bar μ m thick commercial poly(ethylene-alt-tetrafluoroethylene) (ETFE) films. The films were made proton conductive by means of irradiation treatment followed by sulfonation. These membranes have exceptionally low water uptake and excellent dimensional stability. The new membranes are investigated widely in a laboratory-scale direct methanol fuel cell (DMFC). The temperature range used in the fuel cell tests was 30-85-bar o C and the measurement results were compared to those of the Nafion ( R)115 membrane. Also methanol permeability through the ETFE-based membrane was measured as a function of temperature, resulting in values less than 10% of the corresponding values for Nafion ( R)115, which was considerably thicker than the experimental membrane. Methanol crossover was reported to decrease when the thickness of the membrane increases, so the ETFE-based membrane compares favourably to Nafion ( R) membranes. The maximum power densities achieved with the experimental ETFE-based membrane were about 40-65% lower than the corresponding values of the Nafion ( R)115 membrane, because of the lower conductivity and noticeably higher IR-losses. Chemical and mechanical stability of the ETFE-based membrane appeared to be promising since it was tested over 2000-bar h in the DMFC without any performance loss

  17. Silica incorporated membrane for wastewater based filtration

    Science.gov (United States)

    Fernandes, C. S.; Bilad, M. R.; Nordin, N. A. H. M.

    2017-10-01

    Membrane technology has long been applied for waste water treatment industries due to its numerous advantages compared to other conventional processes. However, the biggest challenge in pressure driven membrane process is membrane fouling. Fouling decreases the productivity and efficiency of the filtration, reduces the lifespan of the membrane and reduces the overall efficiency of water treatment processes. In this study, a novel membrane material is developed for water filtration. The developed membrane incorporates silica nanoparticles mainly to improve its structural properties. Membranes with different loadings of silica nanoparticles were applied in this study. The result shows an increase in clean water permeability and filterability of the membrane for treating activated sludge, microalgae solution, secondary effluent and raw sewage as feed. Adding silica into the membrane matrix does not significantly alter contact angle and membrane pore size. We believe that silica acts as an effective pore forming agent that increases the number of pores without significantly altering the pore sizes. A higher number of small pores on the surface of the membrane could reduce membrane fouling because of a low specific loading imposed to individual pores.

  18. Membrane-based technologies for biogas separations.

    Science.gov (United States)

    Basu, Subhankar; Khan, Asim L; Cano-Odena, Angels; Liu, Chunqing; Vankelecom, Ivo F J

    2010-02-01

    Over the past two decades, membrane processes have gained a lot of attention for the separation of gases. They have been found to be very suitable for wide scale applications owing to their reasonable cost, good selectivity and easily engineered modules. This critical review primarily focuses on the various aspects of membrane processes related to the separation of biogas, more in specific CO(2) and H(2)S removal from CH(4) and H(2) streams. Considering the limitations of inorganic materials for membranes, the present review will only focus on work done with polymeric materials. An overview on the performance of commercial membranes and lab-made membranes highlighting the problems associated with their applications will be given first. The development studies carried out to enhance the performance of membranes for gas separation will be discussed in the subsequent section. This review has been broadly divided into three sections (i) performance of commercial polymeric membranes (ii) performance of lab-made polymeric membranes and (iii) performance of mixed matrix membranes (MMMs) for gas separations. It will include structural modifications at polymer level, polymer blending, as well as synthesis of mixed matrix membranes, for which addition of silane-coupling agents and selection of suitable fillers will receive special attention. Apart from an overview of the different membrane materials, the study will also highlight the effects of different operating conditions that eventually decide the performance and longevity of membrane applications in gas separations. The discussion will be largely restricted to the studies carried out on polyimide (PI), cellulose acetate (CA), polysulfone (PSf) and polydimethyl siloxane (PDMS) membranes, as these membrane materials have been most widely used for commercial applications. Finally, the most important strategies that would ensure new commercial applications will be discussed (156 references).

  19. Metal-organic frameworks based membranes for liquid separation.

    Science.gov (United States)

    Li, Xin; Liu, Yuxin; Wang, Jing; Gascon, Jorge; Li, Jiansheng; Van der Bruggen, Bart

    2017-11-27

    Metal-organic frameworks (MOFs) represent a fascinating class of solid crystalline materials which can be self-assembled in a straightforward manner by the coordination of metal ions or clusters with organic ligands. Owing to their intrinsic porous characteristics, unique chemical versatility and abundant functionalities, MOFs have received substantial attention for diverse industrial applications, including membrane separation. Exciting research activities ranging from fabrication strategies to separation applications of MOF-based membranes have appeared. Inspired by the marvelous achievements of MOF-based membranes in gas separations, liquid separations are also being explored for the purpose of constructing continuous MOFs membranes or MOF-based mixed matrix membranes. Although these are in an emerging stage of vigorous development, most efforts are directed towards improving the liquid separation efficiency with well-designed MOF-based membranes. Therefore, as an increasing trend in membrane separation, the field of MOF-based membranes for liquid separation is highlighted in this review. The criteria for judicious selection of MOFs in fabricating MOF-based membranes are given. Special attention is paid to rational design strategies for MOF-based membranes, along with the latest application progress in the area of liquid separations, such as pervaporation, water treatment, and organic solvent nanofiltration. Moreover, some attractive dual-function applications of MOF-based membranes in the removal of micropollutants, degradation, and antibacterial activity are also reviewed. Finally, we define the remaining challenges and future opportunities in this field. This Tutorial Review provides an overview and outlook for MOF-based membranes for liquid separations. Further development of MOF-based membranes for liquid separation must consider the demands of strict separation standards and environmental safety for industrial application.

  20. Metal–organic frameworks based membranes for liquid separation

    KAUST Repository

    Li, Xin

    2017-11-07

    Metal-organic frameworks (MOFs) represent a fascinating class of solid crystalline materials which can be self-assembled in a straightforward manner by the coordination of metal ions or clusters with organic ligands. Owing to their intrinsic porous characteristics, unique chemical versatility and abundant functionalities, MOFs have received substantial attention for diverse industrial applications, including membrane separation. Exciting research activities ranging from fabrication strategies to separation applications of MOF-based membranes have appeared. Inspired by the marvelous achievements of MOF-based membranes in gas separations, liquid separations are also being explored for the purpose of constructing continuous MOFs membranes or MOF-based mixed matrix membranes. Although these are in an emerging stage of vigorous development, most efforts are directed towards improving the liquid separation efficiency with well-designed MOF-based membranes. Therefore, as an increasing trend in membrane separation, the field of MOF-based membranes for liquid separation is highlighted in this review. The criteria for judicious selection of MOFs in fabricating MOF-based membranes are given. Special attention is paid to rational design strategies for MOF-based membranes, along with the latest application progress in the area of liquid separations, such as pervaporation, water treatment, and organic solvent nanofiltration. Moreover, some attractive dual-function applications of MOF-based membranes in the removal of micropollutants, degradation, and antibacterial activity are also reviewed. Finally, we define the remaining challenges and future opportunities in this field. This Tutorial Review provides an overview and outlook for MOF-based membranes for liquid separations. Further development of MOF-based membranes for liquid separation must consider the demands of strict separation standards and environmental safety for industrial application.

  1. Membrane-based biomolecular smart materials

    International Nuclear Information System (INIS)

    Sarles, Stephen A; Leo, Donald J

    2011-01-01

    Membrane-based biomolecular materials are a new class of smart material that feature networks of artificial lipid bilayers contained within durable synthetic substrates. Bilayers contained within this modular material platform provide an environment that can be tailored to host an enormous diversity of functional biomolecules, where the functionality of the global material system depends on the type(s) and organization(s) of the biomolecules that are chosen. In this paper, we review a series of biomolecular material platforms developed recently within the Leo Group at Virginia Tech and we discuss several novel coupling mechanisms provided by these hybrid material systems. The platforms developed demonstrate that the functions of biomolecules and the properties of synthetic materials can be combined to operate in concert, and the examples provided demonstrate how the formation and properties of a lipid bilayer can respond to a variety of stimuli including mechanical forces and electric fields

  2. Lignin-based membranes for electrolyte transference

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xiao; Garcia-Valls, Ricard [Departament d' Enginyeria Quimica, Escola Tecnica Superior d' Enginyeria Quimica, Universitat Rovira i Virgili, Av. Paisos Catalans 26, 43007 Tarragona (Spain); Benavente, Juana [Department of Applied Fisics, Faculty of Science, University of Malaga, Malaga (Spain)

    2005-08-18

    Homogeneous PSf-LS membranes are formed by incorporating Lignosulfonate (LS) into the Polysulfone (PSf) network. LS obtained from sulfite pulping process contains sulfonic acid groups that will act as proton transport media. PSf-LS membranes were characterized by reflectance Infrared and scanning electron microscopy. LS showed significant influence on membrane morphology. Higher LS concentration caused a decrease in macrovoid formation and induced larger pores. Precipitation temperature was investigated as influencing parameter. Proton fluxes through PSf-LS membranes were measured by transport experiments. Impedance analysis confirmed that PSf-LS membranes possess ion conductivity. The selected PSf-LS membranes exhibited high selectivity for proton over methanol, which indicates their potential applicability in direct methanol fuel cell (DMFC). (author)

  3. Toward Anhydrous Proton Conductivity Based on Imidazole Functionalized Mesoporous Silica/Nafion Composite Membranes

    International Nuclear Information System (INIS)

    Amiinu, Ibrahim Saana; Li, Wei; Wang, Guangjin; Tu, Zhengkai; Tang, Haolin; Pan, Mu; Zhang, Haining

    2015-01-01

    Highlights: • Imidazole-functionalized mesoporous silica/Nafion composite is formed. • Electrostatic interaction between ionic clusters leads to enhanced molecular rigidity and T g . • Charge transfer resistance decreases with increase in temperature up to 130 °C. • The composite membrane exhibited considerable stability over 70 h at 130 °C. - Abstract: Although Nafion is regarded as the most preferred electrolyte membrane and often used as a benchmark for comparative evaluation of other electrolyte membranes, its wide spread for commercial PEM fuel cells is limited by the poor electrochemical properties at elevated temperatures and low relative humidity conditions. Herein, sol–gel synthesized mesoporous silica functionalized with a protogenic molecule (imidazole) is introduced into the Nafion matrix via a colloid mediated process. The formation of a stable colloid enables homogeneous dispersion of the silica-imidazole nanoparticles without aggregation. Under non-humidified conditions, the amphoteric and self-dissociative character of the tethered imidazole within the matrix functions as a transporting medium to facilitate proton conductivity. The structural and chemical phases are characterized, and qualitatively evaluated by XRD, TEM, FT-IR, TGA, and DMA. The results show that the average proton conductivity of the composite membrane with the optimal amount of functionalized nanoparticles increases progressively to 1.06 × 10 −2 S cm −1 at 130 °C, corresponding to an activation energy of 6.95 kJ mol −1 under non-humidified conditions. The mechanism governing the dynamics of proton conductivity and structural limitations as a function of temperature is discussed

  4. New Electrorelease Systems Based on Microporous Membranes

    Science.gov (United States)

    1990-08-02

    correspondence (6) we demonstrated the validity of the concept by showing that insulin and vitamin B-12 can be electroreleased from a composite membrane...applied to the membrane. The dye reservoir contained an aqueous solution of either methylene blue dye (Aldrich), K3 Fe(CN)6 (Baker), or bovine insulin

  5. Modeling and PSO optimization of Humidifier-Dehumidifier desalination

    Directory of Open Access Journals (Sweden)

    Mohammad Hossein Ahmadi

    2018-02-01

    Full Text Available The aim of this study is modeling a solar-air heater humidification-dehumidification unit with applying particle swarm optimization to find out  the maximum gained output ratio with respect to the mass flow rate of water and air entering humidifier, mass flow rate of cooling water entering dehumidifier, width and length of solar air heater and terminal temperature difference (TTD of dehumidifier representing temperature difference of inlet cooling water and saturated air to dehumidifier as its decision variable. A sensitivity analysis, furthermore, is performed to distinguish the effect of operating parameters including mass flow rate and streams’ temperature. The results showed that the optimum productivity decreases by decreasing the ratio of mass flow rate of water entering humidifier to air ones. Article History: Received: July 12th 2017; Revised: December 15th 2017; Accepted: 2nd February 2018; Available online How to Cite This Article: Afshar, M.A., Naseri, A., Bidi, M., Ahmadi, M.H. and Hadiyanto, H. (2018 Modeling and PSO Optimization of Humidifier-Dehumidifier Desalination. International Journal of Renewable Energy Development, 7(1,59-64. https://doi.org/10.14710/ijred.7.1.59-64

  6. 3002 Humidified Tandem Differential Mobility Analyzer Instrument Handbook

    Energy Technology Data Exchange (ETDEWEB)

    Uin, Janek [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2016-03-01

    The Brechtel Manufacturing Inc. (BMI) Humidified Tandem Differential Mobility Analyzer (HT-DMA Model 3002) (Brechtel and Kreidenweis 2000a,b, Henning et al. 2005, Xerxes et al. 2014) measures how aerosol particles of different initial dry sizes grow or shrink when exposed to changing relative humidity (RH) conditions. It uses two different mobility analyzers (DMA) and a humidification system to make the measurements. One DMA selects a narrow size range of dry aerosol particles, which are exposed to varying RH conditions in the humidification system. The second (humidified) DMA scans the particle size distribution output from the humidification system. Scanning a wide range of particle sizes enables the second DMA to measure changes in size or growth factor (growth factor = humidified size/dry size), due to water uptake by the particles. A Condensation Particle Counter (CPC) downstream of the second DMA counts particles as a function of selected size in order to obtain the number size distribution of particles exposed to different RH conditions.

  7. Mathematical model and minimal measurement system for optimal control of heated humidifiers in neonatal ventilation.

    Science.gov (United States)

    Verta, Antonella; Schena, Emiliano; Silvestri, Sergio

    2010-06-01

    The control of thermo-hygrometric conditions of gas delivered in neonatal mechanical ventilation appears to be a particularly difficult task, mainly due to the vast number of parameters to be monitored and the control strategies of heated humidifiers to be adopted. In the present paper, we describe the heat and fluid exchange occurring in a heated humidifier in mathematical terms; we analyze the sensitivity of the relative humidity of outlet gas as a function of thermo-hygrometric and fluid-dynamic parameters of delivered gas; we propose a control strategy that will enable the stability of outlet gas thermo-hygrometric conditions. The mathematical model is represented by a hyper-surface containing the functional relations between the input variables, which must be measured, and the output variables, which have to remain constant. Model sensitivity analysis shows that heated humidifier efficacy and stability of outlet gas thermo-hygrometric conditions are principally influenced by four parameters: liquid surface temperature, gas flow rate, inlet gas temperature and inlet gas relative humidity. The theoretical model has been experimentally validated in typical working conditions of neonatal applications. The control strategy has been implemented by a minimal measurement system composed of three thermometers, a humidity sensor, and a flow rate sensor, and based on the theoretical model. Outlet relative humidity, contained in the range 90+/-4% and 94+/-4%, corresponding with temperature variations in the range 28+/-2 degrees C and 38+/-2 degrees C respectively, has been obtained in the whole flow rate range typical of neonatal ventilation from 1 to 10 L/min. We conclude that in order to obtain the stability of the thermo-hygrometric conditions of the delivered gas mixture: (a) a control strategy with a more complex measurement system must be implemented (i.e. providing more input variables); (b) and the gas may also need to be pre-warmed before entering the humidifying

  8. Nanostructured Polysulfone-Based Block Copolymer Membranes

    KAUST Repository

    Xie, Yihui

    2016-01-01

    polycondensation and reversible addition-fragmentation chain-transfer polymerization. The obtained membrane has a highly porous interconnected skin layer composed of elongated micelles with a flower-like arrangement, on top of the graded finger-like macrovoids

  9. Novel thermal efficiency-based model for determination of thermal conductivity of membrane distillation membranes

    International Nuclear Information System (INIS)

    Vanneste, Johan; Bush, John A.; Hickenbottom, Kerri L.; Marks, Christopher A.; Jassby, David

    2017-01-01

    Development and selection of membranes for membrane distillation (MD) could be accelerated if all performance-determining characteristics of the membrane could be obtained during MD operation without the need to recur to specialized or cumbersome porosity or thermal conductivity measurement techniques. By redefining the thermal efficiency, the Schofield method could be adapted to describe the flux without prior knowledge of membrane porosity, thickness, or thermal conductivity. A total of 17 commercially available membranes were analyzed in terms of flux and thermal efficiency to assess their suitability for application in MD. The thermal-efficiency based model described the flux with an average %RMSE of 4.5%, which was in the same range as the standard deviation on the measured flux. The redefinition of the thermal efficiency also enabled MD to be used as a novel thermal conductivity measurement device for thin porous hydrophobic films that cannot be measured with the conventional laser flash diffusivity technique.

  10. Styrene-Based Copolymer for Polymer Membrane Modifications

    OpenAIRE

    Harsha Srivastava; Harshad Lade; Diby Paul; G. Arthanareeswaran; Ji Hyang Kweon

    2016-01-01

    Poly(vinylidene fluoride) (PVDF) was modified with a styrene-based copolymer. The crystalline behavior, phase, thermal stability, and surface morphology of the modified membranes were analyzed. The membrane surface roughness showed a strong dependence on the styrene-acrylonitrile content and was reduced to 34% for a PVDF/styrene-acrylonitrile blend membrane with a 40/60 ratio. The thermal and crystalline behavior confirmed the blend miscibility of both polymers. It was observed in X-ray diffr...

  11. A novel control strategy to improve the performances of heated wire humidifiers in artificial neonatal ventilation

    International Nuclear Information System (INIS)

    Schena, E; Saccomandi, P; Ramandi, C; Silvestri, S

    2012-01-01

    Controlling thermo-hygrometric conditions of gas delivered in neonatal mechanical ventilation shows some unresolved issues due to the design and control strategies implemented in heated wire humidifiers. We perform an in vitro evaluation of humidifier performances, which use a control strategy based on a single-point temperature as feedback, and propose a novel design of the control which consists in pre-warming the gas upwards in the humidification chamber. The ad hoc developed control approach based on a theoretical model is implemented in vitro with and without pre-warming for comparative purposes. Without pre-warming, gas at the chamber outlet needs further post-warming and, depending on the flow rate, the vapour content condensates along the breathing circuit. Whereas, with pre-warming, the proposed control strategy allows us to considerably improve steady-state thermo-hygrometric conditions (T = 37 ± 1 °C, RH = 96% ± 4%) of gas, reaching the Y-piece near to ideal ones in the whole flow rate range, even though a high inlet chamber temperature is required at low flow rate values. The proposed solution, as theoretically predicted, also allows us to limit the vapour condensation along the circuit. (paper)

  12. Exposure characteristics of familial cases of lung injury associated with the use of humidifier disinfectants

    OpenAIRE

    Park, Donguk; Leem, Jonghan; Lee, Kyoungmu; Lim, Heungkyu; Choi, Yeyong; Ahn, Jong-Ju; Lim, Sinye; Park, Jeongim; Choi, Kyungho; Lee, Naroo; Jung, Hyejung; Ha, Jongsik; Paek, Domyung

    2014-01-01

    Background This study describes 17 families with 38 lung injury patients (14 males, 24 females; 22 preschool-age children less than six years of age and 16 individuals of 13–50 years) who used disinfectant added to humidifiers in the home. Methods Clinical examination and humidifier disinfectant-use histories were taken, and a thorough home investigation was performed to assess exposure to humidifier disinfectant. Results Nine of the patients (three pregnant females, six preschool-age childre...

  13. Association of high-level humidifier disinfectant exposure with lung injury in preschool children.

    Science.gov (United States)

    Park, Dong-Uk; Ryu, Seung-Hun; Roh, Hyun-Suk; Lee, Eun; Cho, Hyun-Ju; Yoon, Jisun; Lee, So-Yeon; Cho, Young Ah; Do, Kyung-Hyun; Hong, Soo-Jong

    2018-03-01

    Children aged ≤6years reportedly account for 52% of victims of humidifier disinfectant-associated lung injuries. To evaluate the association of humidifier disinfectants with lung injury risk among children aged ≤6years. Patients with humidifier disinfectant-associated lung injuries (n=214) who were clinically evaluated to have a definite (n=108), probable (n=49), or possible (n=57) association with humidifier disinfectants as well as control patients (n=123) with lung injury deemed unlikely to be associated with humidifier disinfectant use were evaluated to determine factors associated with increased risk of humidifier disinfectant-associated lung injury using unconditional multiple logistic regression analysis. For estimated airborne humidifier disinfectant concentrations, risk of humidifier disinfectant-associated lung injury increased ≥two-fold in a dose-dependent manner in the highest quartile (Q4, 135-1443μg/m 3 ) compared with that in the lowest quartile (Q1, ≤33μg/m 3 ). Registered patients using more than two humidifier disinfectant brands were at an increased risk of humidifier disinfectant-associated lung injury (adjusted OR, 2.2; 95% confidence interval, 1.3-3.8) compared with those using only one brand. With respect to the duration of humidifier disinfectant use, risk of humidifier disinfectant-associated lung injury increased ≥two-fold in the lowest quartile (≤5months) compared with that in the highest quartile (≥14months; adjusted OR 0.3; 95% confidence interval, 0.2-0.6). Younger children are more vulnerable to HDLI when exposed to HD chemicals within short period in early life. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Mechanical ventilation with heated humidifiers: measurements of condensed water mass within the breathing circuit according to ventilatory settings

    International Nuclear Information System (INIS)

    Schena, E; Saccomandi, P; Cappelli, S; Silvestri, S

    2013-01-01

    Heated wire humidifiers (HWHs) are widely used to heat and humidify gases during mechanical ventilation. The control strategy implemented on commercial HWHs, based on maintaining constant gas temperature at the chamber outlet, shows weaknesses: humidifying performances depend on environmental temperature and ventilatory settings, and often condensation occurs. Herein, we analyzed in vitro HWH performances focusing on the condensation amount according to ventilatory settings. We used a physical model to define the parameters which mainly influence the HWH performances. In order to investigate the influence of minute volume (MV) and frequency rate (f r ) on condensation, the other influencing parameters were kept constant during experiments, and we introduced a novel approach to estimate the condensation. The method, based on measuring the condensed vapor mass (Δm), provided more objective information than the visual-based scale used in previous studies. Thanks to both the control of other influencing factors and the accurate Δm measures, the investigation showed the Δm increase with MV and f r . Substantial condensation after 7 h of ventilation and the influence of MV and f r on Δm (i.e., Δm = 3 g at MV = 1.5 L min −1 and f r = 8 bpm and Δm = 9.4 g at MV = 8 L min −1 and f r = 20 bpm) confirm the weaknesses of 'single-point temperature' control strategies. (paper)

  15. Ultrafiltration and Nanofiltration Multilayer Membranes Based on Cellulose

    KAUST Repository

    Livazovic, Sara

    2016-06-09

    Membrane processes are considered energy-efficient for water desalination and treatment. However most membranes are based on polymers prepared from fossil petrochemical sources. The development of multilayer membranes for nanofiltration and ultrafiltration, with thin selective layers of naturally available cellulose, has been hampered by the availability of non-aggressive solvents. We propose the manufacture of cellulose membranes based on two approaches: (i) silylation, coating from solutions in tetrahydrofuran, followed by solvent evaporation and cellulose regeneration by acid treatment; (ii) casting from solution in 1-ethyl-3-methylimidazolum acetate ([C2mim]OAc), an ionic liquid, followed by phase inversion in water. In the search for less harsh, greener membrane manufacture, the combination of cellulose and ionic liquid is of high interest. Due to the abundance of OH groups and hydrophilicity, cellulose-based membranes have high permeability and low fouling tendency. Membrane fouling is one of the biggest challenges in membrane industry and technology. Accumulation and deposition of foulants onto the surface reduce membrane efficiency and requires harsh chemical cleaning, therefore increasing the cost of maintenance and replacement. In this work the resistance of cellulose 5 membranes towards model organic foulants such as Suwanee River Humic Acid (SRHA) and crude oil have been investigated. Cellulose membrane was tested in this work for oil-water (o/w) separation and exhibited practically 100 % oil rejection with good flux recovery ratio and membrane resistivity. The influence of anionic, cationic and ionic surfactant as well as pH and crude oil concentration on oil separation was investigated, giving a valuable insight in experimental and operational planning.

  16. Microbiological contamination in high and low flow oxygen humidifiers: A systematic review.

    Science.gov (United States)

    de la Fuente-Sancho, I; Romeu-Bordas, Ó; Fernández-Aedo, I; Vallejo De la Hoz, G; Ballesteros-Peña, S

    2017-12-16

    To determine the risk of microbiological contamination with hospital use high- and low-flow bubbling humidifiers. A systematic literature review was carried out in 6 databases. Observational or experimental studies published between 1990 and 2016 were selected, written in English or Spanish, and in which microbiological contamination with hospital use high- and low-flow bubbling humidifiers was investigated. A total of 12 articles were included: 4 analyzed the water from reusable humidifiers, 4 analyzed the water from prefilled system humidifiers, and the rest compared samples from both models. Microbial contamination was observed in all studies in which reusable humidifiers were evaluated, usually involving common bacteria from the skin flora, while potential pathogenic species were notified in 2 studies. No microbial contamination was isolated from reusable humidifiers, regardless of whether they had been consecutively used over time by a single patient or by several patients. On one hand, there seems to be a low risk of contamination during the first weeks of use of prefilled humidifiers, which allows multiple use in different patients, without a risk of cross-contamination. On the other hand, it should be underscored that handling reusable humidifiers without correct aseptic measures can increase the risk of contamination; replacing reusable humidifiers with prefilled models therefore could be the safest option. Copyright © 2017. Publicado por Elsevier España, S.L.U.

  17. Design and development of an air humidifier using finite difference method for a solar desalination plant

    Science.gov (United States)

    Chiranjeevi, C.; Srinivas, T.

    2017-11-01

    Humidifier is an important component in air humidification-dehumidification desalination plant for fresh water production. Liquid to air flow rate ratio is optimization is reported for an industrial cooling towers but for an air humidifier it is not addressed. The current work is focused on the design and analysis of an air humidifier for solar desalination plant to maximize the yield with better humidification, using finite difference method (FDM). The outlet conditions of air from the humidifier are theoretically predicted by FDM with the given inlet conditions, which will be further used in the design calculation of the humidifier. Hot water to air flow rate ratio and inlet hot water temperature are identified as key operating parameters to evaluate the humidifier performance. The maximum and optimal values of mass flow rate ratio of water to air are found to be 2.15 and 1.5 respectively using packing function and Merkel Integral. The height of humidifier is constrained to 1.5 m and the diameter of the humidifier is found as 0.28m. The performance of humidifier and outlet conditions of air are simulated using FDM and compared with experimental results. The obtained results are within an agreeable range of deviation.

  18. Proton Conductivity and Operational Features Of PBI-Based Membranes

    DEFF Research Database (Denmark)

    Qingfeng, Li; Jensen, Jens Oluf; Precht Noyé, Pernille

    2005-01-01

    As an approach to high temperature operation of PEMFCs, acid-doped PBI membranes are under active development. The membrane exhibits high proton conductivity under low water contents at temperatures up to 200°C. Mechanisms of proton conduction for the membranes have been proposed. Based on the me...... on the membranes fuel cell tests have been demonstrated. Operating features of the PBI cell include no humidification, high CO tolerance, better heat utilization and possible integration with fuel processing units. Issues for further development are also discussed....

  19. Gas pre-warming for improving performances of heated humidifiers in neonatal ventilation.

    Science.gov (United States)

    Schena, E; De Paolis, E; Silvestri, S

    2011-01-01

    Adequate temperature and humidification of gas delivered must be performed during long term neonatal ventilation to avoid potential adverse health effects. Literature shows that performances of heated humidifiers are, at least in some cases, quite poor. In this study, a novel approach to gas conditioning, consisting of gas warming upstream the humidification chamber, is presented. Gas pre-warming, in combination with a control strategy based on a mathematical model taking into account a number of parameters, allows to significantly improve the heated humidifier performances. The theoretical model has been validated and experimental trials have been carried out in the whole volumetric flow-rate (Q) range of neonatal ventilation (lower than 10 L · min(-1)). Experimental results (temperature values ranging from 36 °C to 38 °C and relative humidity values from 90 % to 98 % in the whole range of Q) show values very close to the ideal thermo-hygrometric conditions. The proposed solution allows to avoid vapor condensation at low flow rates and decrease of relative humidity at high flow rates.

  20. Techno-economical evaluation of membrane based biogas upgrading system: A comparison between polymeric membrane and carbon membrane technology

    Directory of Open Access Journals (Sweden)

    Shamim Haider

    2016-10-01

    Full Text Available A shift to renewable energy sources will reduce emissions of greenhouse gases and secure future energy supplies. In this context, utilization of biogas will play a prominent role. Focus of this work is upgrading of biogas to fuel quality by membrane separation using a carbon hollow fibre (CHF membrane and compare with a commercially available polymeric membrane (polyimide through economical assessment. CHF membrane modules were prepared for pilot plant testing and performance measured using CO2, O2, N2. The CHF membrane was modified through oxidation, chemical vapour deposition (CVD and reduction process thus tailoring pores for separation and increased performance. The post oxidized and reduced carbon hollow fibres (PORCHFs significantly exceeded CHF performance showing higher CO2 permeance (0.021 m3(STP/m2 h bar and CO2/CH4 selectivity of 246 (5 bar feed vs 50 mbar permeate pressure. The highest performance recorded through experiments (CHF and PORCHF was used as simulation basis. A membrane simulation model was used and interfaced to 8.6 V Aspen HYSYS. A 300 Nm3/h mixture of CO2/CH4 containing 30–50% CO2 at feed pressures 6, 8 and 10 bar, was simulated and process designed to recover 99.5% CH4 with 97.5% purity. Net present value (NPV was calculated for base case and optimal pressure (50 bar for CHF and PORCHF. The results indicated that recycle ratio (recycle/feed ranged from 0.2 to 10, specific energy from 0.15 to 0.8 (kW/Nm3feed and specific membrane area from 45 to 4700 (m2/Nm3feed. The high recycle ratio can create problems during start-up, as it would take long to adjust volumetric flow ratio towards 10. The best membrane separation system employs a three-stage system with polyimide at 10 bar, and a two-stage membrane system with PORCHF membranes at 50 bar with recycle. Considering biomethane price of 0.78 $/Nm3 and a lifetime of 15 years, the techno-economic analysis showed that payback time for

  1. New Development of Membrane Base Optoelectronic Devices

    Directory of Open Access Journals (Sweden)

    Leon Hamui

    2017-12-01

    Full Text Available It is known that one factor that affects the operation of optoelectronic devices is the effective protection of the semiconductor materials against environmental conditions. The permeation of atmospheric oxygen and water molecules into the device structure induces degradation of the electrodes and the semiconductor. As a result, in this communication we report the fabrication of semiconductor membranes consisting of Magnesium Phthalocyanine-allene (MgPc-allene particles dispersed in Nylon 11 films. These membranes combine polymer properties with organic semiconductors properties and also provide a barrier effect for the atmospheric gas molecules. They were prepared by high vacuum evaporation and followed by thermal relaxation technique. For the characterization of the obtained membranes, Fourier-transform infrared spectroscopy (FT-IR, scanning electron microscopy (SEM, and energy dispersive spectroscopy (EDS were used to determine the chemical and microstructural properties. UV-ViS, null ellipsometry, and visible photoluminescence (PL at room temperature were used to characterize the optoelectronic properties. These results were compared with those obtained for the organic semiconductors: MgPc-allene thin films. Additionally, semiconductor membranes devices have been prepared, and a study of the device electronic transport properties was conducted by measuring electrical current density-voltage (J-V characteristics by four point probes with different wavelengths. The resistance properties against different environmental molecules are enhanced, maintaining their semiconductor functionality that makes them candidates for optoelectronic applications.

  2. Catalyst Degradation in High Temperature Proton Exchange Membrane Fuel Cells Based on Acid Doped Polybenzimidazole Membranes

    DEFF Research Database (Denmark)

    Cleemann, Lars Nilausen; Buazar, F.; Li, Qingfeng

    2013-01-01

    and multi‐walled carbon nanotubes were used as supports for electrode catalysts and evaluated in accelerated durability tests under potential cycling at 150 °C. Measurements of open circuit voltage, area specific resistance and hydrogen permeation through the membrane were carried out, indicating little...... contribution of the membrane degradation to the performance losses during the potential cycling tests. As the major mechanism of the fuel cell performance degradation, the electrochemical active area of the cathodic catalysts showed a steady decrease in the cyclic voltammetric measurements, which was also......Degradation of carbon supported platinum catalysts is a major failure mode for the long term durability of high temperature proton exchange membrane fuel cells based on phosphoric acid doped polybenzimidazole membranes. With Vulcan carbon black as a reference, thermally treated carbon black...

  3. Membrane materials based on polyheteroarylenes and their application for pervaporation

    International Nuclear Information System (INIS)

    Pulyalina, A Yu; Polotskaya, G A; Toikka, A M

    2016-01-01

    Studies on the transport properties of membrane materials are topical in connection with the need to solve the fundamental problems and to analyze the applied aspects of the theory of membrane separation processes including, in particular, the development of the energy- and resource-saving, environmentally safe technologies. The aim of the review is to generalize the experimental data on the separation of practically valuable mixtures using membranes based on polyheteroarylenes (thermally stable and mechanically strong polymers). First of all, our analysis covers publications that give a detailed description of the physicochemical properties of the membranes and an interpretation of the specific features of mass transfer during pervaporation of liquid mixtures using membrane materials based on polyheteroarylenes. The dependences of the transport parameters of pervaporation on the process conditions and on the methods for production of membrane materials are discussed. The data presented may be useful for the development of the theory of membrane processes taking into account the chemical nature and physicochemical features of polymeric membrane materials. The bibliography includes 151 references

  4. An experimental study of a solar humidifier for HDD systems

    International Nuclear Information System (INIS)

    Ghazal, M.T.; Atikol, U.; Egelioglu, F.

    2014-01-01

    Highlights: • Solar water and air heating and humidification processes have been merged in one unit. • The effectiveness of the solar humidifier was improved. • Bubbles regeneration enhanced the mass and heat transfer to air. • Reflector mirror enhanced the productivity of the system. - Abstract: This paper investigates the performance of a solar humidification prototype suitable for using in humidification dehumidification desalination (HDD) systems. This unit replaces the solar air heater, solar water heater and the evaporator of the traditional HDD plants, facilitating compact system designs. The prototype is composed of a solar collector, filled with water, through which air is forced to travel upwards in the form of bubbles. Experiments are conducted under the weather conditions of North Cyprus. It is discovered that the air temperature is found to approach the hot water temperature in the collector (thus increasing the vapor carrying capacity) and the relative humidity is raised to almost 100% at the exit. The collector inlet and outlet temperatures and relative humidity values are recorded for different flow rates in the period between the 1st and the 14th of December, 2012. It was found that for an average intensity of solar radiation of 700 W/m 2 and a mass flow rate of 12.6 kg/h of air; the amount of water evaporated was 0.75 kg/h on a square meter basis. Introduction of a reflector mirror at the bottom side of the humidifier increased the average absolute humidity by 32%

  5. An experimental investigation of a novel design air humidifier using direct solar thermal heating

    International Nuclear Information System (INIS)

    Abd-ur-Rehman, Hafiz M.; Al-Sulaiman, Fahad A.

    2016-01-01

    Highlights: • A novel solar driven multi-stage bubble column humidifier is developed and tested. • Single stage, two stage, and three stage configuration were tested. • Average day round absolute humidity is increased by 9% for 2 stage configuration. • Average day round absolute humidity is increased by 23% for 3 stage configuration. • Air absolute humidity increases up to 26% with the integration of Fresnel lens. - Abstract: In this study, a novel solar heated multi-stage bubble column humidifier is designed and tested. The overall objective of this work is to investigate the main operating parameters of the new humidifier. The study addresses the significance of the perforated plate geometric features, optimum balance of air superficial velocity and water column height, and the influence of inlet water temperature and inlet air relative humidity on the performance of the humidifier. The day round performance of the humidifier is investigated in single stage, two stage, and three stage configuration, in which each configuration was tested with and without the integration of the Fresnel lens. Findings show that the average day round absolute humidity, without Fresnel lens, increased up to 9% for the two stage configuration and 23% for the three stage configuration as compared to the single stage configuration of the humidifier. The integration of the Fresnel lens further increased the absolute humidity up to 25% as compared to the results obtained without the integration of the Fresnel lens under the same prevailing conditions, which is significant. Moreover, the current humidifier shows a higher humidification efficiency in the climatic conditions that have a lower inlet air relative humidity. Furthermore, the finding demonstrates that the newly developed multi-stage bubble column humidifier has better performance as compared to the conventional single stage bubble column humidifier. The findings from this study are of pivotal importance to understand

  6. SURVEY REGARDING THE ULTRAFILTRATION OF PROTEINES THROUGH MEMBRANE BASED PROCEDURES

    Directory of Open Access Journals (Sweden)

    CAMELIA HODOSAN

    2008-05-01

    Full Text Available This work is based on examples that emphasize the complexity of the proteins ultrafiltration process, pointing out the first 10-15 minutes of ultrafiltration. The knowledgement of the factors that influence the separation through ultrafiltration of proteins will allow to choose the right type of membrane, the frequent use of the same membrane and the operation in mechanical and chemical conditions adequate to the ultrafiltration system, when it is separated a protein with certain molecular weight.

  7. Membrane-based removal of volatile methylsiloxanes from biogas

    Energy Technology Data Exchange (ETDEWEB)

    Ajhar, Marc

    2011-12-16

    This work investigates the removal of volatile methylsiloxanes (VMS) from biogas using dense, rubbery membranes. It consists of the following: a) thorough overview of already established and still developing siloxane removal technologies, b) detailed investigation of a viable sampling and analytical method, c) screening of different elastomers to identify siloxane-selective membrane materials, d) design of a suitable membrane structure, i.e. theoretical considerations about the thicknesses of the active separation layer and the porous support layer, e) assessment of the siloxane separation performance of a silicone membrane module using both synthetic gas under laboratory conditions and real landfill gas, f) comparison between the state-of-the-art technology (adsorption on activated carbon) and membrane-based processes. Suitable polymers for siloxane removal from biogas exist, however, they are not commercially available as membranes. Among the elastomers studied, Pebax registered 2533 is particularly promising. The use of a membrane made of this material could potentially become new state-of-the-art technology.

  8. Membrane-based seawater desalination: Present and future prospects

    KAUST Repository

    Amy, Gary L.

    2016-10-20

    Given increasing regional water scarcity and that almost half of the world\\'s population lives within 100 km of an ocean, seawater represents a virtually infinite water resource. However, its exploitation is presently limited by the significant specific energy consumption (kWh/m) required by conventional desalination technologies, further exasperated by high unit costs ($/m) and environmental impacts including GHG emissions (g CO-eq/m), organism impingement/entrainment through intakes, and brine disposal through outfalls. This paper explores the state-of-the-art in present seawater desalination practice, emphasizing membrane-based technologies, while identifying future opportunities in step improvements to conventional technologies and development of emerging, potentially disruptive, technologies through advances in material science, process engineering, and system integration. In this paper, seawater reverse osmosis (RO) serves as the baseline conventional technology. The discussion extends beyond desalting processes into membrane-based salinity gradient energy production processes, which can provide an energy offset to desalination process energy requirements. The future membrane landscape in membrane-based desalination and salinity gradient energy is projected to include ultrahigh permeability RO membranes, renewable-energy driven desalination, and emerging processes including closed-circuit RO, membrane distillation, forward osmosis, pressure retarded osmosis, and reverse electrodialysis according various niche applications and/or hybrids, operating separately or in conjunction with RO.

  9. Membrane-based torque magnetometer: Enhanced sensitivity by optical readout of the membrane displacement

    Science.gov (United States)

    Blankenhorn, M.; Heintze, E.; Slota, M.; van Slageren, J.; Moores, B. A.; Degen, C. L.; Bogani, L.; Dressel, M.

    2017-09-01

    The design and realization of a torque magnetometer is reported that reads the deflection of a membrane by optical interferometry. The compact instrument allows for low-temperature measurements of tiny crystals less than a microgram with a significant improvement in sensitivity, signal-to-noise ratio as well as data acquisition time compared with conventional magnetometry and offers an enormous potential for further improvements and future applications in different fields. Magnetic measurements on single-molecule magnets demonstrate the applicability of the membrane-based torque magnetometer.

  10. Silicon Micropore-Based Parallel Plate Membrane Oxygenator.

    Science.gov (United States)

    Dharia, Ajay; Abada, Emily; Feinberg, Benjamin; Yeager, Torin; Moses, Willieford; Park, Jaehyun; Blaha, Charles; Wright, Nathan; Padilla, Benjamin; Roy, Shuvo

    2018-02-01

    Extracorporeal membrane oxygenation (ECMO) is a life support system that circulates the blood through an oxygenating system to temporarily (days to months) support heart or lung function during cardiopulmonary failure until organ recovery or replacement. Currently, the need for high levels of systemic anticoagulation and the risk for bleeding are main drawbacks of ECMO that can be addressed with a redesigned ECMO system. Our lab has developed an approach using microelectromechanical systems (MEMS) fabrication techniques to create novel gas exchange membranes consisting of a rigid silicon micropore membrane (SμM) support structure bonded to a thin film of gas-permeable polydimethylsiloxane (PDMS). This study details the fabrication process to create silicon membranes with highly uniform micropores that have a high level of pattern fidelity. The oxygen transport across these membranes was tested in a simple water-based bench-top set-up as well in a porcine in vivo model. It was determined that the mass transfer coefficient for the system using SµM-PDMS membranes was 3.03 ± 0.42 mL O 2 min -1 m -2 cm Hg -1 with pure water and 1.71 ± 1.03 mL O 2 min -1 m -2 cm Hg -1 with blood. An analytic model to predict gas transport was developed using data from the bench-top experiments and validated with in vivo testing. This was a proof of concept study showing adequate oxygen transport across a parallel plate SµM-PDMS membrane when used as a membrane oxygenator. This work establishes the tools and the equipoise to develop future generations of silicon micropore membrane oxygenators. © 2017 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

  11. Aquaporin-Based Biomimetic Polymeric Membranes: Approaches and Challenges

    DEFF Research Database (Denmark)

    Habel, Joachim Erich Otto; Hansen, Michael; Kynde, Søren

    2015-01-01

    In recent years, aquaporin biomimetic membranes (ABMs) for water separation have gained considerable interest. Although the first ABMs are commercially available, there are still many challenges associated with further ABM development. Here, we discuss the interplay of the main components of ABMs...... thin film interfacial polymerization techniques. Finally, we describe some new developments in interfacial polymerization using polyhedral oligomeric silsesquioxane cages for increasing the physical and chemical durability of thin film composite membranes.......In recent years, aquaporin biomimetic membranes (ABMs) for water separation have gained considerable interest. Although the first ABMs are commercially available, there are still many challenges associated with further ABM development. Here, we discuss the interplay of the main components of ABMs...... for investigating AQP incorporation including freeze-fracture transmission electron microscopy, fluorescence correlation spectroscopy, stopped-flow light scattering, and small-angle X-ray scattering. Third, we focus on recent efforts in embedding reconstituted AQPs in membrane designs that are based on conventional...

  12. What must be done to prevent another humidifier disinfectant disaster?

    Directory of Open Access Journals (Sweden)

    Jong-Hyeon Lee

    2016-11-01

    Full Text Available The humidifier disinfectant disaster (HDD was not a simple poisoning accident by biocides, but a singular disaster in history created by chemicals in household products. This disaster was a result of the failure of a system for the management of chemical and product safety. Since the management authority for chemical usage safety is different from those for chemical safety in products, many blind areas for chemical safety management in products still remain. The ‘Act on the Registration and Evaluation, etc. of Chemical Substances (ARECS’ or the new ‘Biocidal Product Act’ must not only address the blind areas in the management system for chemical and product safety, but also prevent a second HDD. To prevent another HDD, an integrated registration, evaluation, and management system for chemicals and consumer products must be incorporated into the ‘ARECS’ as an essential part for chemical safety in consumer products.

  13. Graphene-based structure, method of suspending graphene membrane, and method of depositing material onto graphene membrane

    Science.gov (United States)

    Zettl, Alexander K.; Meyer, Jannik Christian

    2013-04-02

    An embodiment of a method of suspending a graphene membrane across a gap in a support structure includes attaching graphene to a substrate. A pre-fabricated support structure having the gap is attached to the graphene. The graphene and the pre-fabricated support structure are then separated from the substrate which leaves the graphene membrane suspended across the gap in the pre-fabricated support structure. An embodiment of a method of depositing material includes placing a support structure having a graphene membrane suspended across a gap under vacuum. A precursor is adsorbed to a surface of the graphene membrane. A portion of the graphene membrane is exposed to a focused electron beam which deposits a material from the precursor onto the graphene membrane. An embodiment of a graphene-based structure includes a support structure having a gap, a graphene membrane suspended across the gap, and a material deposited in a pattern on the graphene membrane.

  14. Humidifiers for oxygen therapy: what risk for reusable and disposable devices?

    Science.gov (United States)

    La Fauci, V; Costa, G B; Facciolà, A; Conti, A; Riso, R; Squeri, R

    2017-06-01

    Nosocomial pneumonia accounts for the vast majority of healthcare-associated infections (HAI). Although numerous medical devices have been discussed as potential vehicles for microorganisms, very little is known about the role played by oxygen humidifiers as potential sources of nosocomial pathogens. The purpose of this research was to evaluate the safety of the reuse of humidifiers by analysing the rate of microbial contamination in reusable and disposable oxygen humidifiers used during therapy, and then discuss their potential role in the transmission of respiratory pathogens. Water samples from reusable and disposable oxygen humidifiers were collected from different wards of the University Hospital of Messina, Italy, where nosocomial pneumonia has a higher incidence rate due to the "critical" clinical conditions of inpatients. In particular, we monitored the Internal Medicine and Pulmonology wards for the medical area; the General Surgery and Thoracic and Cardiovascular Surgery wards for the surgical area and the Intensive Care Unit and Neonatal Intensive Care Unit for the emergency area. The samples were always collected after a period of 5 days from initial use for both types of humidifiers. Samples were processed using standard bacteriological techniques and microbial colonies were identified using manual and automated methods. High rates of microbial contamination were observed in samples from reusable oxygen humidifiers employed in medical (83%), surgical (77%) and emergency (50%) areas. The most relevant pathogens were Pseudomonas aeruginosa, amongst the Gram-negative bacteria, and Staphylococcus aureus, amongst the Gram-positive bacteria. Other pathogens were detected in lower percentage. The disposable oxygen humidifier samples showed no contamination. This research presents evidence of the high rate and type of microbial contamination of reusable humidifiers employed for oxygen therapy. These devices may thus be involved in the transmission of potential

  15. Refractive-index-based screening of membrane-protein-mediated transfer across biological membranes.

    Science.gov (United States)

    Brändén, Magnus; Tabaei, Seyed R; Fischer, Gerhard; Neutze, Richard; Höök, Fredrik

    2010-07-07

    Numerous membrane-transport proteins are major drug targets, and therefore a key ingredient in pharmaceutical development is the availability of reliable, efficient tools for membrane transport characterization and inhibition. Here, we present the use of evanescent-wave sensing for screening of membrane-protein-mediated transport across lipid bilayer membranes. This method is based on a direct recording of the temporal variations in the refractive index that occur upon a transfer-dependent change in the solute concentration inside liposomes associated to a surface plasmon resonance (SPR) active sensor surface. The applicability of the method is demonstrated by a functional study of the aquaglyceroporin PfAQP from the malaria parasite Plasmodium falciparum. Assays of the temperature dependence of facilitated diffusion of sugar alcohols on a single set of PfAQP-reconstituted liposomes reveal that the activation energies for facilitated diffusion of xylitol and sorbitol are the same as that previously measured for glycerol transport in the aquaglyceroporin of Escherichia coli (5 kcal/mole). These findings indicate that the aquaglyceroporin selectivity filter does not discriminate sugar alcohols based on their length, and that the extra energy cost of dehydration of larger sugar alcohols, upon entering the pore, is compensated for by additional hydrogen-bond interactions within the aquaglyceroporin pore. Copyright 2010 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  16. Aquaporin-Based Biomimetic Polymeric Membranes: Approaches and Challenges

    Science.gov (United States)

    Habel, Joachim; Hansen, Michael; Kynde, Søren; Larsen, Nanna; Midtgaard, Søren Roi; Jensen, Grethe Vestergaard; Bomholt, Julie; Ogbonna, Anayo; Almdal, Kristoffer; Schulz, Alexander; Hélix-Nielsen, Claus

    2015-01-01

    In recent years, aquaporin biomimetic membranes (ABMs) for water separation have gained considerable interest. Although the first ABMs are commercially available, there are still many challenges associated with further ABM development. Here, we discuss the interplay of the main components of ABMs: aquaporin proteins (AQPs), block copolymers for AQP reconstitution, and polymer-based supporting structures. First, we briefly cover challenges and review recent developments in understanding the interplay between AQP and block copolymers. Second, we review some experimental characterization methods for investigating AQP incorporation including freeze-fracture transmission electron microscopy, fluorescence correlation spectroscopy, stopped-flow light scattering, and small-angle X-ray scattering. Third, we focus on recent efforts in embedding reconstituted AQPs in membrane designs that are based on conventional thin film interfacial polymerization techniques. Finally, we describe some new developments in interfacial polymerization using polyhedral oligomeric silsesquioxane cages for increasing the physical and chemical durability of thin film composite membranes. PMID:26264033

  17. Potentiometric measurement of polymer-membrane electrodes based on lanthanum

    Energy Technology Data Exchange (ETDEWEB)

    Saefurohman, Asep, E-mail: saefurohman.asep78@Gmail.com; Buchari,, E-mail: saefurohman.asep78@Gmail.com; Noviandri, Indra, E-mail: saefurohman.asep78@Gmail.com [Department of Chemistry, Bandung Institute of Technology (Indonesia); Syoni [Department of Metallurgy Engineering, Bandung Institute of Technology (Indonesia)

    2014-03-24

    Quantitative analysis of rare earth elements which are considered as the standard method that has a high accuracy, and detection limits achieved by the order of ppm is inductively coupled plasma atomic emission spectroscopy (ICPAES). But these tools are expensive and valuable analysis of the high cost of implementation. In this study be made and characterized selective electrode for the determination of rare earth ions is potentiometric. Membrane manufacturing techniques studied is based on immersion (liquid impregnated membrane) in PTFE 0.5 pore size. As ionophores to be used tri butyl phosphate (TBP) and bis(2-etylhexyl) hydrogen phosphate. There is no report previously that TBP used as ionophore in polymeric membrane based lanthanum. Some parameters that affect the performance of membrane electrode such as membrane composition, membrane thickness, and types of membrane materials studied in this research. Manufacturing of Ion Selective Electrodes (ISE) Lanthanum (La) by means of impregnation La membrane in TBP in kerosene solution has been done and showed performance for ISE-La. FTIR spectrum results for PTFE 0.5 pore size which impregnated in TBP and PTFE blank showed difference of spectra in the top 1257 cm{sup −1}, 1031 cm{sup −1} and 794.7 cm{sup −1} for P=O stretching and stretching POC from group −OP =O. The result showed shift wave number for P =O stretching of the cluster (−OP=O) in PTFE-TBP mixture that is at the peak of 1230 cm{sup −1} indicated that no interaction bond between hydroxyl group of molecules with molecular clusters fosforil of TBP or R{sub 3}P = O. The membrane had stable responses in pH range between 1 and 9. Good responses were obtained using 10{sup −3} M La(III) internal solution, which produced relatively high potential. ISE-La showed relatively good performances. The electrode had a response time of 29±4.5 second and could be use for 50 days. The linear range was between 10{sup −5} and 10{sup −1} M.

  18. based anion exchange membrane for alkaline polymer electrolyte

    Indian Academy of Sciences (India)

    Administrator

    Abstract. Hydroxyl ion (OH–) conducting anion exchange membranes based on modified poly (phenylene oxide) are fabricated for their application in alkaline polymer electrolyte fuel cells (APEFCs). In the present study, chloromethylation of poly(phenylene oxide) (PPO) is performed by aryl substitution rather than benzyl.

  19. Fullerene and dendrimer based nano-composite gas separation membranes

    NARCIS (Netherlands)

    Sterescu, D.M.

    2007-01-01

    This thesis describes the development of new materials for membrane based gas separation processes. Long-term stable, loosely packed (high free volume) amorphous polymer films were prepared by introduction of super-molecular pendant groups, which possess hardsphere properties to avoid dense

  20. Surface characterization of hemodialysis membranes based on streaming potential measurements.

    Science.gov (United States)

    Werner, C; Jacobasch, H J; Reichelt, G

    1995-01-01

    Hemodialysis membranes made from cellulose (CUPROPHAN, HEMOPHAN) and sulfonated polyethersulfone (SPES) were characterized using the streaming potential technique to determine the zeta potential at their interfaces against well-defined aqueous solutions of varied pH and potassium chloride concentrations. Streaming potential measurements enable distinction between different membrane materials. In addition to parameters of the electrochemical double layer at membrane interfaces, thermodynamic characteristics of adsorption of different solved species were evaluated. For that aim a description of double layer formation as suggested by Börner and Jacobasch (in: Electrokinetic Phenomena, p. 231. Institut für Technologie der Polymere, Dresden (1989)) was applied which is based on the generally accepted model of the electrochemical double layer according to Stern (Z. Elektrochemie 30, 508 (1924)) and Grahame (Chem. Rev. 41, 441 (1947)). The membranes investigated show different surface acidic/basic and polar/nonpolar behavior. Furthermore, alterations of membrane interfaces through adsorption processes of components of biologically relevant solutions were shown to be detectable by streaming potential measurements.

  1. Carbon Nano tubes Based Mixed Matrix Membrane for Gas Separation

    International Nuclear Information System (INIS)

    Sanip, S.M.; Ismail, A.F.; Goh, P.S.; Norrdin, M.N.A.; Soga, T.; Tanemura, M.; Yasuhiko, H.

    2011-01-01

    Carbon nano tubes based mixed matrix membrane (MMM) was prepared by the solution casting method in which the functionalized multi walled carbon nano tubes (f-MWNTs) were embedded into the polyimide membrane and the resulting membranes were characterized. The effect of nominal MWNTs content between 0.5 and 1.0 wt % on the gas separation properties were looked into. The morphologies of the MMM also indicated that at 0.7 % loading of f- MWNTs, the structures of the MMM showed uniform finger-like structures which have facilitated the fast gas transport through the polymer matrix. It may also be concluded that addition of open ended and shortened MWNTs to the polymer matrix can improve its permeability by increasing diffusivity through the MWNTs smooth cavity. (author)

  2. The Management of Humidifying Treatment for Low Contamination Risks During Indoor Cultivation of Grey Oyster Mushroom (Pleurotus pulmonarius

    Directory of Open Access Journals (Sweden)

    Islam Md. Tariqul

    2017-01-01

    Full Text Available In this study, grey oyster mushroom (Pleurotus pulmonarius was cultivated in indoor controlled environment to seeking out the possible risks of contamination and ways of treatment to avoid the contamination. For this, mushroom was cultivated in providing artificial humidifying and ventilation system to ensure optimum humidity (80-90% and fresh air recirculation in different ways of treatment. The ways of treatment were included as in position of humidifier, frequency of humidifying, plastic cork of bags opening part and cleaning of humidifier water container. Maximum percentages of bag contamination (2.5-25.30%, cap contamination (5.6-30.75%, stalk contamination (4.75-23.25% and root contamination (2.6-18.45% were found in front to front humidifier position, long humidifying with long interval frequency, without plastic cork, without cleaning and bi-monthly cleaning of humidifier water container treatment but no diseases and pest infection was found. Whereas, very low percentages of contamination (0.1-0.5% were found in surrounding humidifying position, short humidifying duration with short interval frequency, with plastic cork and weekly cleaning of humidifier water container treatment.

  3. Durability Issues of High Temperature Proton Exchange Membrane Fuel Cells Based on Acid Doped Polybenzimidazole Membranes

    DEFF Research Database (Denmark)

    . As a critical concern, issues of long term durability of PBI based fuel cells are addressed in this talk, including oxidative degradation of the polymer, mechanical failures of the membrane, acid leaching out, corrosion of carbon support and sintering of catalysts particles. Excellent polymer durability has...... or ionically cross-linking and structure modification With load, thermal or startup-shutdown cycling, the performance loss was found to be much bigger, about 300 µV per cycle or 40 µV per operating hour, due to the increased acid loss and catalyst support corrosion, particularly under open circuit voltage...... operation. Further efforts are outlined to the future work....

  4. Bio-Mimetic Sensors Based on Molecularly Imprinted Membranes

    Science.gov (United States)

    Algieri, Catia; Drioli, Enrico; Guzzo, Laura; Donato, Laura

    2014-01-01

    An important challenge for scientific research is the production of artificial systems able to mimic the recognition mechanisms occurring at the molecular level in living systems. A valid contribution in this direction resulted from the development of molecular imprinting. By means of this technology, selective molecular recognition sites are introduced in a polymer, thus conferring it bio-mimetic properties. The potential applications of these systems include affinity separations, medical diagnostics, drug delivery, catalysis, etc. Recently, bio-sensing systems using molecularly imprinted membranes, a special form of imprinted polymers, have received the attention of scientists in various fields. In these systems imprinted membranes are used as bio-mimetic recognition elements which are integrated with a transducer component. The direct and rapid determination of an interaction between the recognition element and the target analyte (template) was an encouraging factor for the development of such systems as alternatives to traditional bio-assay methods. Due to their high stability, sensitivity and specificity, bio-mimetic sensors-based membranes are used for environmental, food, and clinical uses. This review deals with the development of molecularly imprinted polymers and their different preparation methods. Referring to the last decades, the application of these membranes as bio-mimetic sensor devices will be also reported. PMID:25196110

  5. Bio-Mimetic Sensors Based on Molecularly Imprinted Membranes

    Directory of Open Access Journals (Sweden)

    Catia Algieri

    2014-07-01

    Full Text Available An important challenge for scientific research is the production of artificial systems able to mimic the recognition mechanisms occurring at the molecular level in living systems. A valid contribution in this direction resulted from the development of molecular imprinting. By means of this technology, selective molecular recognition sites are introduced in a polymer, thus conferring it bio-mimetic properties. The potential applications of these systems include affinity separations, medical diagnostics, drug delivery, catalysis, etc. Recently, bio-sensing systems using molecularly imprinted membranes, a special form of imprinted polymers, have received the attention of scientists in various fields. In these systems imprinted membranes are used as bio-mimetic recognition elements which are integrated with a transducer component. The direct and rapid determination of an interaction between the recognition element and the target analyte (template was an encouraging factor for the development of such systems as alternatives to traditional bio-assay methods. Due to their high stability, sensitivity and specificity, bio-mimetic sensors-based membranes are used for environmental, food, and clinical uses. This review deals with the development of molecularly imprinted polymers and their different preparation methods. Referring to the last decades, the application of these membranes as bio-mimetic sensor devices will be also reported.

  6. Fabrication of miniaturised Si-based electrocatalytic membranes

    International Nuclear Information System (INIS)

    D'Arrigo, G.; Spinella, C.; Arena, G.; Lorenti, S.

    2003-01-01

    The increasing interest for light and movable electronic systems, cell phones and small digital devices, drives the technological research toward integrated regenerating power sources with small dimensions and great autonomy. Conventional batteries are already unable to deliver power in more and more shrunk volumes maintaining the requirements of long duration and light weight. A possible solution to overcome these limits is the use of miniaturised fuel cell. The fuel cell offers a greater gravimetric energy density compared to conventional batteries. The micromachining technology of silicon is an important tool to reduce the fuel cell structure to micrometer sizes. The use of silicon also gives the opportunity to integrate the power source and the electronic circuits controlling the fuel cell on the same structure. This paper reports preliminary results concerning the micromachining procedure for fabricating a Si-based electrocatalytic membrane for miniaturised Si-based proton exchange membrane fuel cells (PEMFC)

  7. Ultrathin nanoporous membranes for insulator-based dielectrophoresis

    Science.gov (United States)

    Mukaibo, Hitomi; Wang, Tonghui; Perez-Gonzalez, Victor H.; Getpreecharsawas, Jirachai; Wurzer, Jack; Lapizco-Encinas, Blanca H.; McGrath, James L.

    2018-06-01

    Insulator-based dielectrophoresis (iDEP) is a simple, scalable mechanism that can be used for directly manipulating particle trajectories in pore-based filtration and separation processes. However, iDEP manipulation of nanoparticles presents unique challenges as the dielectrophoretic force ({F}{{D}{{E}}{{P}}}) exerted on the nanoparticles can easily be overshadowed by opposing kinetic forces. In this study, a molecularly thin, SiN-based nanoporous membrane (NPN) is explored as a breakthrough technology that enhances {F}{{D}{{E}}{{P}}}. By numerically assessing the gradient of the electric field square ({{\

  8. Humidifier disinfectant lung injury, how do we approach the issues?

    Directory of Open Access Journals (Sweden)

    Jihyun Emma Choi

    2016-08-01

    Full Text Available A large portion of the Korean population has been exposed to toxic humidifier disinfectants (HDs, and considering that the majority of the victims are infants, the magnitude of the damage is expected to be considerably larger than what has currently been revealed. The current victims are voicing problems caused by various diseases, including but not limited to lung, upper respiratory tract, cardiovascular, kidney, musculoskeletal, eye, and skin diseases, etc. However, there has been difficulty in gaining validation for these health problems and identifying causal relationships due to lack of evidence proving that toxic HD is the specific causes of extrapulmonary diseases such as allergic rhinitis. Furthermore, the victims and bereaved families of the HD case have not received any support for psychological distress such as post-traumatic stress disorder, depression, feelings of injustice, and anger caused by the trauma. In addition, because the underlying mechanisms of the toxic materials within the HDs such as polyhexamethylene guanidine phosphate, poly(oxyalkylene guanidine hydrochloride, chloromethylisothiazolinone/methylisothiazolinone have yet to be determined, the demand for information regarding the HD issue is growing. The victims of the HD cases require support that goes beyond financial aid for medical costs and living expenses. There is a desperate need for government-led integrated support centers that provide individualized support through health screenings; in other words, we need an integrated facility that provides the appropriate social support to allow the victims to recover their physical and mental health, so as to well prepare them to return to a normal life. The implementation of such a plan requires not only the close cooperation between those departments already directly involved such as the Ministry of Environment and the Ministry of Health and Welfare, but also active support on a national scale from pan

  9. Evaluation report on the causal association between humidifier disinfectants and lung injury

    Directory of Open Access Journals (Sweden)

    Mina Ha

    2016-08-01

    Full Text Available OBJECTIVES As of November 2011, the Korean government recalled and banned humidifier disinfectants (HDs from the market, because four case-control studies and one retrospective epidemiological study proved the association between HDs and lung injury of unknown cause. The report reviewed the causal role of HDs in lung injury based on scientific evidences. METHODS A careful examination on the association between the HDs and lung injury was based on the criteria of causality inference by Hill and the US Surgeon General Expert Committee. RESULTS We found that all the evidences on the causality fulfilled the criteria (strength of association, consistency, specificity, temporality, biologic gradient, plausibility, coherence, experiment, analogy, consideration of alternative explanations, and cessation of exposure, which proved the unknown cause lung injury reported in 2011 was caused by the HDs. In particular, there was no single reported case of lung injury since the ban in selling HDs in November 2011 as well as before the HDs were sold in markets. CONCLUSIONS Although only a few epidemiological studies in Korea have evaluated the association between lung injury and the use of HDs, those studies contributed to proving the strong association between the use of the HDs and lung injury, based on scientific evidence.

  10. Ceramic membrane fuel cells based on solid proton electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Meng, Guangyao; Ma, Qianli; Peng, Ranran; Liu, Xingqin [USTC Lab. for Solid State Chemistry and Inorganic Membranes, Department of Materials Science and Engineering, University of Science and Technology of China, Hefei 230026 (China); Ma, Guilin [School of Chemistry and Chemical Engineering, Suzhou University, Suzhou 215123 (China)

    2007-04-15

    The development of solid oxide fuel cells (SOFCs) has reached its new stage characterized with thin electrolytes on porous electrode support, and the most important fabrication techniques developed in which almost all are concerned with inorganic membranes, and so can be named as ceramic membrane fuel cells (CMFCs). CMFCs based on proton electrolytes (CMFC-H) may exhibit more advantages than CMFCs based on oxygen-ion electrolytes (CMFC-O) in many respects, such as energy efficiency and avoiding carbon deposit. Ammonia fuelled CMFC with proton-conducting BaCe{sub 0.8}Gd{sub 0.2}O{sub 2.9} (BCGO) electrolyte (50 {mu}m in thickness) is reported in this works, which showed the open current voltage (OCV) values close to theoretical ones and rather high power density. And also, we have found that the well known super oxide ion conductor, La{sub 0.9}Sr{sub 0.1}Ga{sub 0.8}Mg{sub 0.2}O{sub 3-{alpha}} (LSGM), is a pure proton conductor in H{sub 2} and mixed proton and oxide ion conductor in wet air, while it is a pure oxide ion conductor in oxygen or dry air. To demonstrate the CMFC-H concept to get high performance fuel cells the techniques for thin membranes, chemical vapor deposition (CVD), particularly novel CVD techniques, should be given more attention because of their many advantages. (author)

  11. MEMS-Based Fuel Reformer with Suspended Membrane Structure

    Science.gov (United States)

    Chang, Kuei-Sung; Tanaka, Shuji; Esashi, Masayoshi

    We report a MEMS-based fuel reformer for supplying hydrogen to micro-fuel cells for portable applications. A combustor and a reforming chamber are fabricated at either side of a suspended membrane structure. This design is used to improve the overall thermal efficiency, which is a critical issue to realize a micro-fuel reformer. The suspended membrane structure design provided good thermal isolation. The micro-heaters consumed 0.97W to maintain the reaction zone of the MEMS-based fuel reformer at 200°C, but further power saving is necessary by improving design and fabrication. The conversion rate of methanol to hydrogen was about 19% at 180°C by using evaporated copper as a reforming catalyst. The catalytic combustion of hydrogen started without any assistance of micro-heaters. By feeding the fuel mixture of an equivalence ratio of 0.35, the temperature of the suspended membrane structure was maintained stable at 100°C with a combustion efficiency of 30%. In future works, we will test a micro-fuel reformer by using a micro-combustor to supply heat.

  12. Continuous Membrane-Based Screening System for Biocatalysis

    Directory of Open Access Journals (Sweden)

    Matthias Kraume

    2011-02-01

    Full Text Available The use of membrane reactors for enzymatic and co-factor regenerating reactions offers versatile advantages such as higher conversion rates and space-time-yields and is therefore often applied in industry. However, currently available screening and kinetics characterization systems are based on batch and fed-batch operated reactors and were developed for whole cell biotransformations rather than for enzymatic catalysis. Therefore, the data obtained from such systems has only limited transferability for continuous membrane reactors. The aim of this study is to evaluate and to improve a novel screening and characterization system based on the membrane reactor concept using the enzymatic hydrolysis of cellulose as a model reaction. Important aspects for the applicability of the developed system such as long-term stability and reproducibility of continuous experiments were very high. The concept used for flow control and fouling suppression allowed control of the residence time with a high degree of precision (±1% accuracy in a long-term study (>100 h.

  13. Randomized Trial of Desktop Humidifier for Dry Eye Relief in Computer Users.

    Science.gov (United States)

    Wang, Michael T M; Chan, Evon; Ea, Linda; Kam, Clifford; Lu, Yvonne; Misra, Stuti L; Craig, Jennifer P

    2017-11-01

    Dry eye is a frequently reported problem among computer users. Low relative humidity environments are recognized to exacerbate signs and symptoms of dry eye, yet are common in offices of computer operators. Desktop USB-powered humidifiers are available commercially, but their efficacy for dry eye relief has not been established. This study aims to evaluate the potential for a desktop USB-powered humidifier to improve tear-film parameters, ocular surface characteristics, and subjective comfort of computer users. Forty-four computer users were enrolled in a prospective, masked, randomized crossover study. On separate days, participants were randomized to 1 hour of continuous computer use, with and without exposure to a desktop humidifier. Lipid-layer grade, noninvasive tear-film breakup time, and tear meniscus height were measured before and after computer use. Following the 1-hour period, participants reported whether ocular comfort was greater, equal, or lesser than that at baseline. The desktop humidifier effected a relative difference in humidity between the two environments of +5.4 ± 5.0% (P .05). However, a relative increase in the median noninvasive tear-film breakup time of +4.0 seconds was observed in the humidified environment (P computer use.Trial registration no: ACTRN12617000326392.

  14. Exposure characteristics of familial cases of lung injury associated with the use of humidifier disinfectants.

    Science.gov (United States)

    Park, Donguk; Leem, Jonghan; Lee, Kyoungmu; Lim, Heungkyu; Choi, Yeyong; Ahn, Jong-Ju; Lim, Sinye; Park, Jeongim; Choi, Kyungho; Lee, Naroo; Jung, Hyejung; Ha, Jongsik; Paek, Domyung

    2014-09-02

    This study describes 17 families with 38 lung injury patients (14 males, 24 females; 22 preschool-age children less than six years of age and 16 individuals of 13-50 years) who used disinfectant added to humidifiers in the home. Clinical examination and humidifier disinfectant-use histories were taken, and a thorough home investigation was performed to assess exposure to humidifier disinfectant. Nine of the patients (three pregnant females, six preschool-age children) died soon after they first developed lung damage. Six (16%) were pregnant females and 22 (58%) were preschool-aged children younger than six years. The patients used humidifier disinfectant products containing either polyhexamethylene guanidine phosphate (PHMG, n = 36) or oligo(2-(2-ethoxy)ethoxyethyl guanidinium chloride (PGH, n = 2). Twenty-six patients (68%) used the brand "Oxy"®, which contains PHMG. Of the ten patients with fatal lung injury, nine were found to have used PHMG. Our findings suggest that the use of humidifier disinfectant products containing either PGH or PHMG can cause lung injury, especially in preschool-age children younger than six years and pregnant women.

  15. An adhesion-based method for plasma membrane isolation: evaluating cholesterol extraction from cells and their membranes.

    Science.gov (United States)

    Bezrukov, Ludmila; Blank, Paul S; Polozov, Ivan V; Zimmerberg, Joshua

    2009-11-15

    A method to isolate large quantities of directly accessible plasma membrane from attached cells is presented. The method is based on the adhesion of cells to an adsorbed layer of polylysine on glass plates, followed by hypotonic lysis with ice-cold distilled water and subsequent washing steps. Optimal conditions for coating glass plates and time for cell attachment were established. No additional chemical or mechanical treatments were used. Contamination of the isolated plasma membrane by cell organelles was less than 5%. The method uses inexpensive, commercially available polylysine and reusable glass plates. Plasma membrane preparations can be made in 15 min. Using this method, we determined that methyl-beta-cyclodextrin differentially extracts cholesterol from fibroblast cells and their plasma membranes and that these differences are temperature dependent. Determination of the cholesterol/phospholipid ratio from intact cells does not reflect methyl-beta-cyclodextrin plasma membrane extraction properties.

  16. Robust membrane detection based on tensor voting for electron tomography.

    Science.gov (United States)

    Martinez-Sanchez, Antonio; Garcia, Inmaculada; Asano, Shoh; Lucic, Vladan; Fernandez, Jose-Jesus

    2014-04-01

    Electron tomography enables three-dimensional (3D) visualization and analysis of the subcellular architecture at a resolution of a few nanometers. Segmentation of structural components present in 3D images (tomograms) is often necessary for their interpretation. However, it is severely hampered by a number of factors that are inherent to electron tomography (e.g. noise, low contrast, distortion). Thus, there is a need for new and improved computational methods to facilitate this challenging task. In this work, we present a new method for membrane segmentation that is based on anisotropic propagation of the local structural information using the tensor voting algorithm. The local structure at each voxel is then refined according to the information received from other voxels. Because voxels belonging to the same membrane have coherent structural information, the underlying global structure is strengthened. In this way, local information is easily integrated at a global scale to yield segmented structures. This method performs well under low signal-to-noise ratio typically found in tomograms of vitrified samples under cryo-tomography conditions and can bridge gaps present on membranes. The performance of the method is demonstrated by applications to tomograms of different biological samples and by quantitative comparison with standard template matching procedure. Copyright © 2014 Elsevier Inc. All rights reserved.

  17. Enhancing Membrane Protein Identification Using a Simplified Centrifugation and Detergent-Based Membrane Extraction Approach.

    Science.gov (United States)

    Zhou, Yanting; Gao, Jing; Zhu, Hongwen; Xu, Jingjing; He, Han; Gu, Lei; Wang, Hui; Chen, Jie; Ma, Danjun; Zhou, Hu; Zheng, Jing

    2018-02-20

    Membrane proteins may act as transporters, receptors, enzymes, and adhesion-anchors, accounting for nearly 70% of pharmaceutical drug targets. Difficulties in efficient enrichment, extraction, and solubilization still exist because of their relatively low abundance and poor solubility. A simplified membrane protein extraction approach with advantages of user-friendly sample processing procedures, good repeatability and significant effectiveness was developed in the current research for enhancing enrichment and identification of membrane proteins. This approach combining centrifugation and detergent along with LC-MS/MS successfully identified higher proportion of membrane proteins, integral proteins and transmembrane proteins in membrane fraction (76.6%, 48.1%, and 40.6%) than in total cell lysate (41.6%, 16.4%, and 13.5%), respectively. Moreover, our method tended to capture membrane proteins with high degree of hydrophobicity and number of transmembrane domains as 486 out of 2106 (23.0%) had GRAVY > 0 in membrane fraction, 488 out of 2106 (23.1%) had TMs ≥ 2. It also provided for improved identification of membrane proteins as more than 60.6% of the commonly identified membrane proteins in two cell samples were better identified in membrane fraction with higher sequence coverage. Data are available via ProteomeXchange with identifier PXD008456.

  18. An analysis of a humidifier disinfectant case from a toxicological perspective

    Directory of Open Access Journals (Sweden)

    Kwangsik Park

    2016-07-01

    Full Text Available An analysis of patients and fatalities due to exposure to polyhexamethylene guanidine (PHMG shows that PHMG causes mainly lung diseases such as pulmonary fibrosis. However, no research on the other organs has been conducted on this matter yet. So, an in-depth discussion on toxicological techniques is needed to determine whether or not PHMG is toxic to organs other than just the lungs. For the test of target organ toxicity by PHMG exposure, a toxicokinetic study must first be conducted. However, measurement method for PHMG injected into the body has not yet been established because it is not easy to analyze polymer PHMG, so related base studies on analytical technique for PHMG including radio-labeling chemistry must come first. Moreover, research on exposure-biomarker and effect-biomarker must also be conducted, primarily related to clinical application. Several limitations seem to be expected to apply the biomarker study to the patient because much time has passed after exposure to the humidifier disinfectant. It is why a more comprehensive toxicological researches must be introduced to the causality for the victims.

  19. An analysis of a humidifier disinfectant case from a toxicological perspective.

    Science.gov (United States)

    Park, Kawangsik

    2016-01-01

    An analysis of patients and fatalities due to exposure to polyhexamethylene guanidine (PHMG) shows that PHMG causes mainly lung diseases such as pulmonary fibrosis. However, no research on the other organs has been conducted on this matter yet. So, an in-depth discussion on toxicological techniques is needed to determine whether or not PHMG is toxic to organs other than just the lungs. For the test of target organ toxicity by PHMG exposure, a toxicokinetic study must first be conducted. However, measurement method for PHMG injected into the body has not yet been established because it is not easy to analyze polymer PHMG, so related base studies on analytical technique for PHMG including radio-labeling chemistry must come first. Moreover, research on exposure-biomarker and effect-biomarker must also be conducted, primarily related to clinical application. Several limitations seem to be expected to apply the biomarker study to the patient because much time has passed after exposure to the humidifier disinfectant. It is why a more comprehensive toxicological researches must be introduced to the causality for the victims.

  20. Biological evaluation of silver nanoparticles incorporated into chitosan-based membranes

    NARCIS (Netherlands)

    Shao, J.; Yu, N.; Kolwijck, E.; Wang, B.; Tan, K.W.; Jansen, J.A.; Walboomers, X.F.; Yang, F.

    2017-01-01

    AIM: To evaluate the antibacterial potential and biological performance of silver nanoparticles in chitosan-based membranes. MATERIALS & METHODS: Electrospun chitosan/poly(ethylene oxide) membranes with different amounts of silver nanoparticles were evaluated for antibacterial properties and

  1. Fabrication and Water Treatment Application of Carbon Nanotubes (CNTs)-Based Composite Membranes: A Review.

    Science.gov (United States)

    Ma, Lining; Dong, Xinfa; Chen, Mingliang; Zhu, Li; Wang, Chaoxian; Yang, Fenglin; Dong, Yingchao

    2017-03-18

    Membrane separation technology is widely explored for various applications, such as water desalination and wastewater treatment, which can alleviate the global issue of fresh water scarcity. Specifically, carbon nanotubes (CNTs)-based composite membranes are increasingly of interest due to the combined merits of CNTs and membrane separation, offering enhanced membrane properties. This article first briefly discusses fabrication and growth mechanisms, characterization and functionalization techniques of CNTs, and then reviews the fabrication methods for CNTs-based composite membranes in detail. The applications of CNTs-based composite membranes in water treatment are comprehensively reviewed, including seawater or brine desalination, oil-water separation, removal of heavy metal ions and emerging pollutants as well as membrane separation coupled with assistant techniques. Furthermore, the future direction and perspective for CNTs-based composite membranes are also briefly outlined.

  2. Tandem malonate-based glucosides (TMGs) for membrane protein structural studies

    DEFF Research Database (Denmark)

    Hussain, Hazrat; Mortensen, Jonas S.; Du, Yang

    2017-01-01

    class of glucoside amphiphiles, designated tandem malonate-based glucosides (TMGs). A few TMG agents proved effective at both stabilizing a range of membrane proteins and extracting proteins from the membrane environment. These favourable characteristics, along with synthetic convenience, indicate...

  3. Fabrication and Water Treatment Application of Carbon Nanotubes (CNTs-Based Composite Membranes: A Review

    Directory of Open Access Journals (Sweden)

    Lining Ma

    2017-03-01

    Full Text Available Membrane separation technology is widely explored for various applications, such as water desalination and wastewater treatment, which can alleviate the global issue of fresh water scarcity. Specifically, carbon nanotubes (CNTs-based composite membranes are increasingly of interest due to the combined merits of CNTs and membrane separation, offering enhanced membrane properties. This article first briefly discusses fabrication and growth mechanisms, characterization and functionalization techniques of CNTs, and then reviews the fabrication methods for CNTs-based composite membranes in detail. The applications of CNTs-based composite membranes in water treatment are comprehensively reviewed, including seawater or brine desalination, oil-water separation, removal of heavy metal ions and emerging pollutants as well as membrane separation coupled with assistant techniques. Furthermore, the future direction and perspective for CNTs-based composite membranes are also briefly outlined.

  4. Membrane-based processes for sustainable power generation using water

    KAUST Repository

    Logan, Bruce E.; Elimelech, Menachem

    2012-01-01

    Water has always been crucial to combustion and hydroelectric processes, but it could become the source of power in membrane-based systems that capture energy from natural and waste waters. Two processes are emerging as sustainable methods for capturing energy from sea water: pressure-retarded osmosis and reverse electrodialysis. These processes can also capture energy from waste heat by generating artificial salinity gradients using synthetic solutions, such as thermolytic salts. A further source of energy comes from organic matter in waste waters, which can be harnessed using microbial fuel-cell technology, allowing both wastewater treatment and power production. © 2012 Macmillan Publishers Limited. All rights reserved.

  5. Membrane-based processes for sustainable power generation using water

    KAUST Repository

    Logan, Bruce E.

    2012-08-15

    Water has always been crucial to combustion and hydroelectric processes, but it could become the source of power in membrane-based systems that capture energy from natural and waste waters. Two processes are emerging as sustainable methods for capturing energy from sea water: pressure-retarded osmosis and reverse electrodialysis. These processes can also capture energy from waste heat by generating artificial salinity gradients using synthetic solutions, such as thermolytic salts. A further source of energy comes from organic matter in waste waters, which can be harnessed using microbial fuel-cell technology, allowing both wastewater treatment and power production. © 2012 Macmillan Publishers Limited. All rights reserved.

  6. Fuel cell membrane preparation: effects of base polymer

    Energy Technology Data Exchange (ETDEWEB)

    Brack, H P; Scherer, G G [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-06-01

    Radiation grafted films and membranes prepared from the partially fluorinated base copolymer poly(ethylene-alt-tetrafluoroethylene) or ETFE have better mechanical properties than those prepared from poly(tetrafluoroethylene-co-hexafluoropropylene) or FEP. The influence of the base copolymer film type on the grafting rate and yields is reported in the present investigation. An understanding of the effects of these parameters is important so that the grafting process can be carried out reproducibly in as short a time as possible. The grafting rate and yield as a function of the irradiation dose has been found to be much higher for the partially fluorinated base copolymer ETFE. (author) 2 figs., 1 tab., 5 refs.

  7. Ultrasonic-based membrane aided sample preparation of urine proteomes.

    Science.gov (United States)

    Jesus, Jemmyson Romário; Santos, Hugo M; López-Fernández, H; Lodeiro, Carlos; Arruda, Marco Aurélio Zezzi; Capelo, J L

    2018-02-01

    A new ultrafast ultrasonic-based method for shotgun proteomics as well as label-free protein quantification in urine samples is developed. The method first separates the urine proteins using nitrocellulose-based membranes and then proteins are in-membrane digested using trypsin. The enzymatic digestion process is accelerated from overnight to four minutes using a sonoreactor ultrasonic device. Overall, the sample treatment pipeline comprising protein separation, digestion and identification is done in just 3h. The process is assessed using urine of healthy volunteers. The method shows that male can be differentiated from female using the protein content of urine in a fast, easy and straightforward way. 232 and 226 proteins are identified in urine of male and female, respectively. From this, 162 are common to both genders, whilst 70 are unique to male and 64 to female. From the 162 common proteins, 13 are present at levels statistically different (p minimalism concept as outlined by Halls, as each stage of this analysis is evaluated to minimize the time, cost, sample requirement, reagent consumption, energy requirements and production of waste products. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Chaos Time Series Prediction Based on Membrane Optimization Algorithms

    Directory of Open Access Journals (Sweden)

    Meng Li

    2015-01-01

    Full Text Available This paper puts forward a prediction model based on membrane computing optimization algorithm for chaos time series; the model optimizes simultaneously the parameters of phase space reconstruction (τ,m and least squares support vector machine (LS-SVM (γ,σ by using membrane computing optimization algorithm. It is an important basis for spectrum management to predict accurately the change trend of parameters in the electromagnetic environment, which can help decision makers to adopt an optimal action. Then, the model presented in this paper is used to forecast band occupancy rate of frequency modulation (FM broadcasting band and interphone band. To show the applicability and superiority of the proposed model, this paper will compare the forecast model presented in it with conventional similar models. The experimental results show that whether single-step prediction or multistep prediction, the proposed model performs best based on three error measures, namely, normalized mean square error (NMSE, root mean square error (RMSE, and mean absolute percentage error (MAPE.

  9. Legionella bacteria in combustion air humidifiers; Legionella i luftuppfuktare foer foerbraenningsluft

    Energy Technology Data Exchange (ETDEWEB)

    Jeppesen, Jessica; Hansson, Helen; Cederfeldt, Ola; Axby, Fredrik

    2007-10-15

    Over the last couple of years several outbreaks of Legionnaires' disease has occurred around the world. The source of infection varies, but in many cases the bacteria has been traced back to cooling towers. The common denominator for most of the sources of infection has been water systems with high oxygen levels and a system temperature ranging from 20 to 40 deg C. If a water system furthermore has high levels of other bacteria/microorganisms, then it is also probable that favorable conditions for legionella bacteria exist within the system. These conditions consist well with conditions in combustion air humidifiers in district heating plants and therefore it can be suspected that legionella may thrive also in these types of air humidifiers. In order to examine if legionella bacteria exists in combustion air humidifiers, and in what quantity, ten different district heating plants where selected for a survey. The goal of the survey is to get a general picture of the extent of the occurrence of legionella bacteria in different types of air humidifiers. This was done by taking legionella tests in three different types of air humidifiers in district heating plants. The first step of the testing was conducted by measuring the level of legionella bacteria in water samples from the air humidifiers in the different plants. The water samples were taken from water that circulates in the air humidifiers. A few months later another water sample was taken from the same location. Two district heating plants, where legionella bacteria had been detected, were selected for further testing after compiling the results from the first two tests. The further testing involved fuel gas analysis to see if any of the plants fuel gas contained legionella bacteria. The test results show that a major part of the district heating plants in the survey have heterotrophic bacteria in their water systems, which implies the possibility of growth of legionella bacteria. About half of the plants

  10. Sulfonated carbon black-based composite membranes for fuel cell ...

    Indian Academy of Sciences (India)

    the properties of the composite membranes with the addition of S–C particles at high concentrations due to the .... metry and nuclear magnetic resonance that assured no sol- ... BT-512 BekkTech membrane test system at varying relative.

  11. Crosslinked wholly aromatic polyether membranes based on quinoline derivatives and their application in high temperature polymer electrolyte membrane fuel cells

    Science.gov (United States)

    Kallitsis, K. J.; Nannou, R.; Andreopoulou, A. K.; Daletou, M. K.; Papaioannou, D.; Neophytides, S. G.; Kallitsis, J. K.

    2018-03-01

    An AB type difunctional quinoline based monomer bearing a pentafluorophenyl unit combined with a phenol functionality is being synthesized and homopolymerized to create linear aromatic polyethers as polymer electrolytes for HT-PEM FCs applications. Several conditions are tested for the optimized synthesis of the monomer and homopolymer. Additionally, covalent crosslinking through aromatic polyether bond formation enables the creation of wholly aromatic crosslinked polymeric electrolyte membranes. More specifically, the perfluorophenyl units are crosslinked with other hydroxyl end functionalized moieties, providing membranes with enhanced chemical and mechanical properties that are moreover easily doped with phosphoric acid even at ambient temperatures. All membranes are evaluated for their structural and thermal characteristics and their doping ability with phosphoric acid. Selected crosslinked membranes are further tested in terms of their single cell performance at the temperature range 160 °C-200 °C showing promising performance and high conductivity values even up to 0.2 S cm-1 in some cases.

  12. Ionic liquid-based materials: a platform to design engineered CO2 separation membranes.

    Science.gov (United States)

    Tomé, Liliana C; Marrucho, Isabel M

    2016-05-21

    During the past decade, significant advances in ionic liquid-based materials for the development of CO2 separation membranes have been accomplished. This review presents a perspective on different strategies that use ionic liquid-based materials as a unique tuneable platform to design task-specific advanced materials for CO2 separation membranes. Based on compilation and analysis of the data hitherto reported, we provide a judicious assessment of the CO2 separation efficiency of different membranes, and highlight breakthroughs and key challenges in this field. In particular, configurations such as supported ionic liquid membranes, polymer/ionic liquid composite membranes, gelled ionic liquid membranes and poly(ionic liquid)-based membranes are detailed, discussed and evaluated in terms of their efficiency, which is attributed to their chemical and structural features. Finally, an integrated perspective on technology, economy and sustainability is provided.

  13. Follow up investigation of workers in synthetic fibre plants with humidifier disease and work related asthma

    NARCIS (Netherlands)

    Pal, TM; de Monchy, JGR; Groothoff, JW; Post, D

    Objective-To investigate the clinical and sociomedical outcome in patients with various clinical manifestations of humidifier disease and work related asthma after removal from further exposure. Methods-Follow up investigation (range 1-13 years) of respiratory symptoms, spirometry, airway

  14. Cellulose acetate-based molecularly imprinted polymeric membrane for separation of vanillin and o-vanillin

    OpenAIRE

    Zhang,Chunjing; Zhong,Shian; Yang,Zhengpeng

    2008-01-01

    Cellulose acetate-based molecularly imprinted polymeric membranes were prepared using vanillin as template molecule. The microscopic structure of the resultant polymeric membranes was characterized by SEM and FTIR spectroscopy, and the selective binding properties and separation capacity of the membranes for vanillin and o-vanillin were tested with binding experiments and separate experiments, respectively. The results showed that the vanillin-imprinted polymeric membranes displayed higher bi...

  15. Microporous Organic Materials for Membrane-Based Gas Separation.

    Science.gov (United States)

    Zou, Xiaoqin; Zhu, Guangshan

    2018-01-01

    Membrane materials with excellent selectivity and high permeability are crucial to efficient membrane gas separation. Microporous organic materials have evolved as an alternative candidate for fabricating membranes due to their inherent attributes, such as permanent porosity, high surface area, and good processability. Herein, a unique pore-chemistry concept for the designed synthesis of microporous organic membranes, with an emphasis on the relationship between pore structures and membrane performances, is introduced. The latest advances in microporous organic materials for potential membrane application in gas separation of H 2 , CO 2 , O 2 , and other industrially relevant gases are summarized. Representative examples of the recent progress in highly selective and permeable membranes are highlighted with some fundamental analyses from pore characteristics, followed by a brief perspective on future research directions. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Human exposure to polyhexamethylene guanidine phosphate from humidifiers in residential settings: Cause of serious lung disease.

    Science.gov (United States)

    Lee, Ji Hyun; Yu, Il Je

    2017-11-01

    Exposure to the humidifier disinfectant, polyhexamethylene guanidine phosphate (PHMG), in mists generated from ultrasonic humidifiers was studied in a simulation chamber and apartment rooms. PHMG is suspected as a causative agent of lung disease in Korea residences. In the simulation-chamber study, the amount of disinfectant discharged from three different ultrasonic humidifiers was measured. Mists generated at 1, 2, and 4 times the recommended amount of disinfectant were sampled with an impinger, and the effect of relative humidity (RH) on airborne disinfectant concentration was studied by changing RH from 60%-70% to 90%-100%. In addition, particle size distribution (PSD) in mists was measured by scanning mobility particle sizer (SMPS), aerodynamic particle sizer (APS), and Mastersizer. In the apartment study, mists generated from ultrasonic humidifiers were sampled for 6 h in small and large rooms during fall ( n = 10) and winter ( n = 15). In the simulation study, the humidifiers discharged 205 ± 24.6 ml/h of mist at maximum capacity. Concentrations of airborne disinfectant increased with increasing concentration of disinfectant. RH affected airborne disinfectant concentration in the chamber, with increasing concentration with increasing RH. Below RH 70%, no airborne PHMG was detected. PHMG-containing mists generated from ultrasonic humidifier showed various sizes ranging from 149-157 nm to 690-740 nm to larger than 5.4 µm by SMPS, APS, and Mastersizer, respectively. Surface area mean diameter measured by Mastersizer ranged from 5.39 µm to 5.72 µm. In the apartment study conducted during the fall, the geometric mean (GM) and geometric standard deviation (GSD) and arithmetic mean (AM) and standard deviation (SD) of airborne PHMG concentration were 3.22 + 5.13 µg/m 3 and 8.26 ± 12.18 µg/m 3 , respectively. In the winter, GM + GSD and AM ± SD of airborne PHMG concentration were 0.21 + 2.11 µg/m 3 and 0.35 ± 0.62 µg/m 3 , respectively. RH and temperature

  17. Palladium based membranes and membrane reactors for hydrogen production and purification : An overview of research activities at Tecnalia and TU/e

    NARCIS (Netherlands)

    Fernandez, E.; Helmi Siasi Farimani, A.; Medrano Jimenez, J.A.; Coenen, K.T.; Arratibel Plazaola, A.; Melendez Rey, J.; de Nooijer, N.C.A.; Viviente, J.L.; Zuniga, J.; van Sint Annaland, M.; Gallucci, F.; Pacheco Tanaka, D.A.

    2017-01-01

    In this paper, the main achievements of several European research projects on Pd based membranes and Pd membrane reactors for hydrogen production are reported. Pd-based membranes have received an increasing interest for separation and purification of hydrogen. In addition, the integration of such

  18. Novel fluoropolymer anion exchange membranes for alkaline direct methanol fuel cells.

    Science.gov (United States)

    Zhang, Yanmei; Fang, Jun; Wu, Yongbin; Xu, Hankun; Chi, Xianjun; Li, Wei; Yang, Yixu; Yan, Ge; Zhuang, Yongze

    2012-09-01

    A series of novel fluoropolymer anion exchange membranes based on the copolymer of vinylbenzyl chloride, butyl methacrylate, and hexafluorobutyl methacrylate has been prepared. Fourier transform infrared (FT-IR) spectroscopy and elemental analysis techniques are used to study the chemical structure and chemical composition of the membranes. The water uptake, ion-exchange capacity (IEC), conductivity, methanol permeability, and chemical stability of the membranes are also determined. The membranes exhibit high anionic conductivity in deionized water at 65 °C ranging from 3.86×10(-2) S cm(-1) to 4.36×10(-2) S cm(-1). The methanol permeability coefficients of the membranes are in the range of 4.21-5.80×10(-8) cm(2) s(-1) at 65 °C. The novel membranes also show good chemical and thermal stability. An open-circuit voltage of 0.7 V and a maximum power density of 53.2 mW cm(-2) of alkaline direct methanol fuel cell (ADMFC) with the membrane C, 1 M methanol, 1 M NaOH, and humidified oxygen are achieved at 65 °C. Therefore, these membranes have great potential for applications in fuel cell systems. Copyright © 2012 Elsevier Inc. All rights reserved.

  19. Novel composite membranes based on PBI and dicationic ionic liquids for high temperature polymer electrolyte membrane fuel cells

    International Nuclear Information System (INIS)

    Hooshyari, Khadijeh; Javanbakht, Mehran; Adibi, Mina

    2016-01-01

    Two types of innovative composite membranes based on polybenzimidazole (PBI) containing dicationic ionic liquid 1,3-di(3-methylimidazolium) propane bis (trifluoromethylsulfonyl) imide (PDC 3 ) and monocationic ionic liquid 1-hexyl-3-methylimidazolium bis (trifluoromethanesulfonyl) imide (PMC 6 ) are prepared as electrolyte for high temperature fuel cells applications under anhydrous conditions. The analyses of results display promising characteristics such as high proton conductivity and thermal stability. Moreover the fuel cell performance of PA doped PDC 3 composite membranes is enhanced in comparison with PA doped PMC 6 and PA doped PBI membranes at high temperatures. Dicationic ionic liquid with high number of charge carriers provides well-developed ionic channels which form facile pathways and considerably develop the anhydrous proton conductivity. The highest proton conductivity of 81 mS/cm is achieved for PA doped PDC 3 composite membranes with PBI/IL mole ratio: 4 at 180 °C. A power density of 0.44 W/cm 2 is obtained at 0.5 V and 180 °C for PA doped PDC 3 composite membranes, which proves that these developed composite membranes can be considered as most promising candidates for high temperature fuel cell applications with enhanced proton conductivity.

  20. Electrolytic membrane formation of fluoroalkyl polymer using a UV-radiation-based grafting technique and sulfonation

    Energy Technology Data Exchange (ETDEWEB)

    Shironita, Sayoko; Mizoguchi, Satoko; Umeda, Minoru, E-mail: mumeda@vos.nagaokaut.ac.jp [Department of Materials Science and Technology, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka 940-2188, Niigata (Japan)

    2011-03-15

    A sulfonated fluoroalkyl graft polymer (FGP) membrane was prepared as a polymer electrolyte. First, the FGP membrane was grafted with styrene under UV irradiation. The grafted FGP was then sulfonated to functionalize it for proton conductivity. The grafting degree of the membrane increased with increasing grafting time during UV irradiation. The proton conductivity of the membrane increased with increasing grafting degree. The swelling ratio was independent of the grafting time, however, the water uptake increased with increasing grafting degree. Based on these results, it was found that the UV-initiated styrene grafting occurred along the membrane thickness direction. Moreover, the membrane was embedded within the glass fibers of the composite. This composite electrolytic membrane had 1.15 times the proton conductivity of a Nafion 117 membrane.

  1. Inhibiting host-pathogen interactions using membrane-based nanostructures.

    Science.gov (United States)

    Bricarello, Daniel A; Patel, Mira A; Parikh, Atul N

    2012-06-01

    Virulent strains of bacteria and viruses recognize host cells by their plasma membrane receptors and often exploit the native translocation machinery to invade the cell. A promising therapeutic concept for early interruption of pathogen infection is to subvert this pathogenic trickery using exogenously introduced decoys that present high-affinity mimics of cellular receptors. This review highlights emerging applications of molecularly engineered lipid-bilayer-based nanostructures, namely (i) functionalized liposomes, (ii) supported colloidal bilayers or protocells and (iii) reconstituted lipoproteins, which display functional cellular receptors in optimized conformational and aggregative states. These decoys outcompete host cell receptors by preferentially binding to and neutralizing virulence factors of both bacteria and viruses, thereby promising a new approach to antipathogenic therapy. Copyright © 2012 Elsevier Ltd. All rights reserved.

  2. Composite proton exchange membrane based on sulfonated organic nanoparticles

    Science.gov (United States)

    Pitia, Emmanuel Sokiri

    exchange was characterized with solid state 13C NMR spectroscopy, FTIR spectroscopy, TGA, elemental analysis, and titration. The results indicate the extent of ion exchange was ~ 70-80%. Due to the mass of QAA, the remaining QAA reduced the IEC of the nanoparticles to < 2.2 meq/g. In fabricating the composite membranes, the nanoparticles and polystyrene were solution cast in a continuous process with and without electric field. The electric field had no effect on the water uptake. Based on the morphology and the proton conductivity, it appears orientation of the nanoparticles did not occur. We hypothesize the lack of orientation was caused by swelling of the particles with the solvent. The solvent inside the particle minimized polarizability, and thus prevented orientation. The composite membranes were limited to low proton conductivity of ~ 10-5 S/cm due to low IEC of the nanoparticles, but good dispersion of the nanoparticles was achieved. Future work should look into eliminating the QAA during synthesis and developing a rigid core for the nanoparticles.

  3. IMIDAZOLE-BASED IONIC LIQUIDS FOR USE IN POLYMER ELECTROLYTE MEMBRANE FUEL CELLS: EFFECT OF ELECTRON-WITHDRAWING AND ELECTRON-DONATING SUBSTITUENTS

    Energy Technology Data Exchange (ETDEWEB)

    Chang, E.; Fu, Y.; Kerr, J.

    2009-01-01

    Current polymer electrolyte membrane fuel cells (PEMFCs) require humidifi cation for acceptable proton conductivity. Development of a novel polymer that is conductive without a water-based proton carrier is desirable for use in automobiles. Imidazole (Im) is a possible replacement for water as a proton solvent; Im can be tethered to the polymer structure by means of covalent bonds, thereby providing a solid state proton conducting membrane where the solvating groups do not leach out of the fuel cell. These covalent bonds can alter the electron availability of the Im molecule. This study investigates the effects of electron-withdrawing and electron-donating substituents on the conductivity of Im complexed with methanesulfonic acid (MSA) in the form of ionic liquids. Due to the changes in the electronegativity of nitrogen, it is expected that 2-phenylimidazole (2-PhIm, electron-withdrawing) will exhibit increased conductivity compared to Im, while 2-methylimidazole (2-MeIm, electron-donating) will exhibit decreased conductivity. Three sets of ionic liquids were prepared at defi ned molar ratios: Im-MSA, 2-PhIm-MSA, and 2-MeIm- MSA. Differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and 1H-NMR were used to characterize each complex. Impedance analysis was used to determine the conductivity of each complex. Both the 2-PhIm-MSA and 2-MeIm-MSA ionic liquids were found to be less conductive than the Im-MSA complex at base-rich compositions, but more conductive at acid-rich compositions. 1H-NMR data shows a downfi eld shift of the proton on nitrogen in 2-PhIm compared to Im, suggesting that other factors may diminish the electronic effects of the electron withdrawing group at base-rich compositions. Further studies examining these effects may well result in increased conductivity for Im-based complexes. Understanding the conductive properties of Im-derivatives due to electronic effects will help facilitate the development of a new electrolyte

  4. Development and characterization of polyacrylonitrile (PAN based carbon hollow fiber membrane

    Directory of Open Access Journals (Sweden)

    Syed Mohd Saufi

    2002-11-01

    Full Text Available This paper reports the development and characterization of polyacrylonitrile (PAN based carbon hollow fiber membrane. Nitrogen was used as an inert gas during pyrolysis of the PAN hollow fiber membrane into carbon membrane. PAN membranes were pyrolyzed at temperature ranging from 500oC to 800oC for 30 minutes of thermal soak time. Scanning Electron Microscope (SEM, Fourier Transform Infrared Spectroscopy (FTIR and gas sorption analysis were applied to characterize the PAN based carbon membrane. Pyrolysis temperature was found to significantly change the structure and properties of carbon membrane. FTIR results concluded that the carbon yield still could be increased by pyrolyzing PAN membranes at temperature higher than 800oC since the existence of other functional group instead of CH group. Gas adsorption analysis showed that the average pore diameter increased up to 800oC.

  5. Novel membrane-based electrochemical sensor for real-time bio-applications

    DEFF Research Database (Denmark)

    Al Atraktchi, Fatima Al-Zahraa; Bakmand, Tanya; Dimaki, Maria

    2014-01-01

    This article presents a novel membrane-based sensor for real-time electrochemical investigations of cellular- or tissue cultures. The membrane sensor enables recording of electrical signals from a cell culture without any signal dilution, thus avoiding loss of sensitivity. Moreover, the porosity...... of the membrane provides optimal culturing conditions similar to existing culturing techniques allowing more efficient nutrient uptake and molecule release. The patterned sensor electrodes were fabricated on a porous membrane by electron-beam evaporation. The electrochemical performance of the membrane electrodes...

  6. Optimized electrode coverage of membrane actuators based on epitaxial PZT thin films

    International Nuclear Information System (INIS)

    Nguyen, M D; Dekkers, M; Blank, D H A; Rijnders, G; Nazeer, H

    2013-01-01

    This research presents an optimization of piezoelectric membrane actuators by maximizing the actuator displacement. Membrane actuators based on epitaxial Pb(Zr,Ti)O 3 thin films grown on all-oxide electrodes and buffer layers using silicon technology were fabricated. Electrode coverage was found to be an important factor in the actuation displacement of the piezoelectric membranes. The optimum electrode coverage for maximum displacement was theoretically determined to be 39%, which is in good agreement with the experimental results. Dependences of membrane displacement and optimum electrode coverage on membrane diameter and PZT-film/Si-device-layer thickness ratio have also been investigated. (paper)

  7. Development of hydrophobic clay–alumina based capillary membrane for desalination of brine by membrane distillation

    Directory of Open Access Journals (Sweden)

    Rakhi Das

    2016-09-01

    Full Text Available Clay–alumina compositions of 0, 20, 40 and 55 weight percent (wt% clay and rest alumina were maintained in porous support preparation by extrusion followed by sintering at 1300 °C for 2.5 h to obtain 3 mm/2 mm (outer diameter/inner diameter capillary. 1H,1H,2H,2H-perfluorodecyltriethoxysilane (97% (C8 was used to modify the capillary surface of all compositions without any intermediate membrane layer to impart hydrophobic characteristics and compared in terms of contact angle produced by the capillaries with water and liquid entry pressure (LEPw. FTIR analysis showed that the hydrophilic surface of the capillary membranes was efficiently modified by the proposed grafting method. Capillary with 55 wt% clay produced a pore size of 1.43 micron and was considered as an ideal candidate for grafting with C8 polymer to impart surface hydrophobicity. The contact angle and LEPw value obtained for this modified membrane (C-55-M were 145° and 1 bar, respectively. The modified capillary membrane was applied for desalination of brine by air gap membrane distillation (AGMD at a feed pressure of 0.85 bar. Maximum flux obtained for C-55-M membrane was 98.66 L/m2 day at a temperature difference of 60 °C with salt rejection of 99.96%. Mass transfer coefficient of C-55-M was 16 × 10−3 mm/s at feed temperature of 70 °C.

  8. Organic/inorganic composite membranes based on polybenzimidazole and nano-SiO2

    International Nuclear Information System (INIS)

    Pu Hongting; Liu Lu; Chang Zhihong; Yuan Junjie

    2009-01-01

    Organic/inorganic composite membranes based on polybenzimidazole (PBI) and nano-SiO 2 were prepared in this work. However, the preparation of PBI/SiO 2 composite membrane is not easy since PBI is insoluble in water, while nano-SiO 2 is hydrophilic due to the hydrophilicity of nano-SiO 2 and water-insolubility of PBI. Thus, a solvent-exchange method was employed to prepare the composite membrane. The morphology of the composite membranes was studied by scanning electron microscopy (SEM). It was revealed that inorganic particles were dispersed homogenously in the PBI matrix. The thermal stability of the composite membrane is higher than that of pure PBI, both for doped and undoped membranes. PBI/SiO 2 composite membranes with up to 15 wt% SiO 2 exhibited improved mechanical properties compared with PBI membranes. The proton conductivity of the composite membranes containing phosphoric acid was studied. The nano-SiO 2 in the composite membranes enhanced the ability to trap phosphoric acid, which improved the proton conductivity of the composite membranes. The membrane with 15 wt% of inorganic material is oxidatively stable and has a proton conductivity of 3.9 x 10 -3 S/cm at 180 deg. C.

  9. Performance Degradation Tests of Phosphoric Acid Doped Polybenzimidazole Membrane Based High Temperature Polymer Electrolyte Membrane Fuel Cells

    DEFF Research Database (Denmark)

    Zhou, Fan; Araya, Samuel Simon; Grigoras, Ionela

    2015-01-01

    Degradation tests of two phosphoric acid (PA) doped PBI membrane based HT-PEM fuel cells were reported in this paper to investigate the effects of start/stop and the presence of methanol in the fuel to the performance degradation of the HT-PEM fuel cell. Continuous tests with pure dry H2 and meth...

  10. Sulfonated carbon black-based composite membranes for fuel cell

    Indian Academy of Sciences (India)

    Composite membranes were then prepared using S–C as fillers and sulfonated poly(ether ether ketone) (SPEEK) as polymer matrix with three different sulfonation degrees (DS = 60, 70 and 82%). Structure and properties of the composite membranes were characterized by FTIR, TGA, scanning electron microscopy, proton ...

  11. Dense ceramic membranes based on ion conducting oxides

    International Nuclear Information System (INIS)

    Fontaine, M.L.; Larring, Y.; Bredesen, R.; Norby, T.; Grande, T.

    2007-01-01

    This chapter reviews the recent progress made in the fields of high temperature oxygen and hydrogen separation membranes. Studies of membranes for oxygen separation are mainly focusing on materials design to improve flux, and to lesser extent, related to stability issues. High oxygen fluxes satisfying industrial requirements can be obtained but, for many materials, the surface exchange rate is limiting the performance. The current status on electrolyte-type and mixed proton and electron conducting membranes is outlined, highlighting materials with improved stability in typical applications as solid oxide fuel cell technology and gas separation. In our presentation more fundamental aspects related to transport properties, chemical and mechanical stability of membrane materials are also treated. It is concluded that a significantly better understanding of the long term effects of operation in chemical gradients is needed for these types of membrane materials. (authors)

  12. System and method for air temperature control in an oxygen transport membrane based reactor

    Science.gov (United States)

    Kelly, Sean M

    2016-09-27

    A system and method for air temperature control in an oxygen transport membrane based reactor is provided. The system and method involves introducing a specific quantity of cooling air or trim air in between stages in a multistage oxygen transport membrane based reactor or furnace to maintain generally consistent surface temperatures of the oxygen transport membrane elements and associated reactors. The associated reactors may include reforming reactors, boilers or process gas heaters.

  13. Crosslinked polybenzimidazoles containing branching structure as membrane materials with excellent cell performance and durability for fuel cell applications

    Science.gov (United States)

    Hu, Meishao; Ni, Jiangpeng; Zhang, Boping; Neelakandan, Sivasubramaniyan; Wang, Lei

    2018-06-01

    Crosslinking is an effective method to improve the properties of high temperature proton exchange membranes based on polybenzimidazole. However, the compact structure of crosslinked polybenzimidazole hinders the phosphoric acid absorption of the membranes, resulting in a relatively poor fuel cell performance. Recently, we find that branched polymers can absorb more phosphoric acid with a larger free volume, but suffer from deteriorated mechanical strength. In this work, a new method is proposed to obtain excellent over-all properties of high temperature proton exchange membranes. A series of crosslinked polybenzimidazoles containing branching structure as membrane materials are successfully prepared for the first time. Compared with conventional crosslinked membranes, these crosslinked polybenzimidazole membranes containing branching structure exhibit a higher phosphoric acid doping level and proton conductivity, improved durability, lower swelling rate and comparable mechanical strength. In particular, the fuel cell base on the crosslinked and branched membrane with a 10% ratio of crosslinker in non-humidified hydrogen/air at 160 °C achieves a power density of 404 mW cm-2. The results indicate that the combination of crosslinking and branching is an effective approach to improve the properties of polybenzimidazole membrane materials.

  14. Synthesis and Characterization of Sulfonated Graphene Oxide Reinforced Sulfonated Poly (Ether Ether Ketone (SPEEK Composites for Proton Exchange Membrane Materials

    Directory of Open Access Journals (Sweden)

    Ning Cao

    2018-03-01

    Full Text Available As a clean energy utilization device, full cell is gaining more and more attention. Proton exchange membrane (PEM is a key component of the full cell. The commercial-sulfonated, tetrafluoroethylene-based fluoropolymer-copolymer (Nafion membrane exhibits excellent proton conductivity under a fully humidified environment. However, it also has some disadvantages in practice, such as high fuel permeability, a complex synthesis process, and high cost. To overcome these disadvantages, a low-cost and novel membrane was developed. The sulfonated poly (ether ether ketone (SPEEK was selected as the base material of the proton exchange membrane. Sulfonated graphene (SG was cross-linked with SPEEK through the elimination reaction of hydrogen bonds. It was found that the sulfonic acid groups and hydrophilic oxygen groups increased obviously in the resultant membrane. Compared with the pure SPEEK membrane, the SG-reinforced membrane exhibited better proton conductivity and methanol permeability prevention. The results indicate that the SG/SPEEK could be applied as a new proton exchange membrane in fuel cells.

  15. Gravikinesis in Stylonychia mytilus is based on membrane potential changes.

    Science.gov (United States)

    Krause, Martin; Bräucker, Richard; Hemmersbach, Ruth

    2010-01-01

    The graviperception of the hypotrichous ciliate Stylonychia mytilus was investigated using electrophysiological methods and behavioural analysis. It is shown that Stylonychia can sense gravity and thereby compensates sedimentation rate by a negative gravikinesis. The graviresponse consists of a velocity-regulating physiological component (negative gravikinesis) and an additional orientational component. The latter is largely based on a physical mechanism but might, in addition, be affected by the frequency of ciliary reversals, which is under physiological control. We show that the external stimulus of gravity is transformed to a physiological signal, activating mechanosensitive calcium and potassium channels. Earlier electrophysiological experiments revealed that these ion channels are distributed in the manner of two opposing gradients over the surface membrane. Here, we show, for the first time, records of gravireceptor potentials in Stylonychia that are presumably based on this two-gradient system of ion channels. The gravireceptor potentials had maximum amplitudes of approximately 4 mV and slow activation characteristics (0.03 mV s(-1)). The presumptive number of involved graviperceptive ion channels was calculated and correlates with the analysis of the locomotive behaviour.

  16. Studies Regarding the Membranous Support of a Glucose Biosensor Based on Gox

    Directory of Open Access Journals (Sweden)

    Otilia Bizerea-Spiridon

    2010-05-01

    Full Text Available To obtain glucose biosensors based on glucose oxidase (GOx, the enzyme can be immobilized on the sensitive surface of a glass electrode by different techniques: deposition on membranous support (cellophane or other macromolecular material or entrapment in a matrix. Deposition on membranous support also involves cross-linking with glutaraldehyde or entrapment in silica gel, following the sol-gel procedure. The aim of this preliminary work was to study the influence of cellophane replacement with a PVA based membranous support on the glucose biosensor performance. The data obtained at pH measurements of buffer solutions with cellophane and PVA membranous supports respectively, show that the PVA based membrane assures superior performances of the biosensor for low glucose concentrations determination (about 10-4 M. These results allow the transition to an improved immobilization technique, namely the enzyme entrapment in membranous material.

  17. Randomized controlled trial on postoperative pulmonary humidification after total laryngectomy: External humidifier versus heat and moisture exchanger

    NARCIS (Netherlands)

    Mérol, Jean-Claude; Charpiot, Anne; Langagne, Thibault; Hémar, Patrick; Ackerstaff, Annemieke H.; Hilgers, Frans J. M.

    2012-01-01

    Objectives/Hypothesis: Assessment of immediate postoperative airway humidification after total laryngectomy (TLE), comparing the use of an external humidifier (EH) with humidification through a heat and moisture exchanger (HME). Study Design: Randomized controlled trial (RCT). Methods: Fifty-three

  18. Randomized controlled trial on postoperative pulmonary humidification after total laryngectomy: external humidifier versus heat and moisture exchanger

    NARCIS (Netherlands)

    Mérol, J.-C.; Charpiot, A.; Langagne, T.; Hémar, P.; Ackerstaff, A.H.; Hilgers, F.J.M.

    2012-01-01

    Objectives/Hypothesis: Assessment of immediate postoperative airway humidification after total laryngectomy (TLE), comparing the use of an external humidifier (EH) with humidification through a heat and moisture exchanger (HME). Study Design: Randomized controlled trial (RCT). Methods: Fifty-three

  19. Novel Blend Membranes Based on Acid-Base Interactions for Fuel Cells

    Directory of Open Access Journals (Sweden)

    Yongzhu Fu

    2012-10-01

    Full Text Available Fuel cells hold great promise for wide applications in portable, residential, and large-scale power supplies. For low temperature fuel cells, such as the proton exchange membrane fuel cells (PEMFCs and direct methanol fuel cells (DMFCs, proton-exchange membranes (PEMs are a key component determining the fuel cells performance. PEMs with high proton conductivity under anhydrous conditions can allow PEMFCs to be operated above 100 °C, enabling use of hydrogen fuels with high-CO contents and improving the electrocatalytic activity. PEMs with high proton conductivity and low methanol crossover are critical for lowering catalyst loadings at the cathode and improving the performance and long-term stability of DMFCs. This review provides a summary of a number of novel acid-base blend membranes consisting of an acidic polymer and a basic compound containing N-heterocycle groups, which are promising for PEMFCs and DMFCs.

  20. Simple membrane-based model of the Min oscillator

    International Nuclear Information System (INIS)

    Petrášek, Zdeněk; Schwille, Petra

    2015-01-01

    Min proteins in E. coli bacteria organize into a dynamic pattern oscillating between the two cell poles. This process identifies the middle of the cell and enables symmetric cell division. In an experimental model system consisting of a flat membrane with effectively infinite supply of proteins and energy source, the Min proteins assemble into travelling waves. Here we propose a simple one-dimensional model of the Min dynamics that, unlike the existing models, reproduces the sharp decrease of Min concentration when the majority of protein detaches from the membrane, and even the narrow MinE maximum immediately preceding the detachment. The proposed model thus provides a possible mechanism for the formation of the MinE ring known from cells. The model is restricted to one dimension, with protein interactions described by chemical kinetics allowing at most bimolecular reactions, and explicitly considering only three, membrane-bound, species. The bulk solution above the membrane is approximated as being well-mixed, with constant concentrations of all species. Unlike other models, our proposal does not require autocatalytic binding of MinD to the membrane. Instead, it is assumed that two MinE molecules are necessary to induce the dissociation of the MinD dimer and its subsequent detachment from the membrane. We investigate which reaction schemes lead to unstable homogeneous steady states and limit cycle oscillations, and how diffusion affects their stability. The suggested model qualitatively describes the shape of the Min waves observed on flat membranes, and agrees with the experimental dependence of the wave period on the MinE concentration. These results highlight the importance of MinE presence on the membrane without being bound to MinD, and of the reactions of Min proteins on the membrane. (paper)

  1. Proton exchange membranes based on PVDF/SEBS blends

    Energy Technology Data Exchange (ETDEWEB)

    Mokrini, A.; Huneault, M.A. [Industrial Materials Institute, National Research Council of Canada, 75 de Mortagne Blvd., Boucherville, Que. (Canada J4B 6Y4)

    2006-03-09

    Proton-conductive polymer membranes are used as an electrolyte in the so-called proton exchange membrane fuel cells. Current commercially available membranes are perfluorosulfonic acid polymers, a class of high-cost ionomers. This paper examines the potential of polymer blends, namely those of styrene-(ethylene-butylene)-styrene block copolymer (SEBS) and polyvinylidene fluoride (PVDF), in the proton exchange membrane application. SEBS/PVDF blends were prepared by twin-screw extrusion and the membranes were formed by calendering. SEBS is a phase-segregated material where the polystyrene blocks can be selectively functionalized offering high ionic conductivity, while PVDF insures good dimensional stability and chemical resistance to the films. Proton conductivity of the films was obtained by solid-state grafting of sulfonic acid moieties. The obtained membranes were characterized in terms of conductivity, ionic exchange capacity and water uptake. In addition, the membranes were characterized in terms of morphology, microstructure and thermo-mechanical properties to establish the blends morphology-property relationships. Modification of interfacial properties between SEBS and PVDF was found to be a key to optimize the blends performance. Addition of a methyl methacrylate-butyl acrylate-methyl methacrylate block copolymer (MMA-BA-MMA) was found to compatibilize the blend by reducing the segregation scale and improving the blend homogeneity. Mechanical resistance of the membranes was also improved through the addition of this compatibilizer. As little as 2wt.% compatibilizer was sufficient for complete interfacial coverage and lead to improved mechanical properties. Compatibilized blend membranes also showed higher conductivities, 1.9x10{sup -2} to 5.5x10{sup -3}Scm{sup -1}, and improved water management. (author)

  2. Studies of rubidium selenate with secondary phase of RbOH under humidified reducing atmosphere

    DEFF Research Database (Denmark)

    Beyribey, Berceste; Hallinder, Jonathan; Poulsen, Finn Willy

    2012-01-01

    The high temperature properties of Rb2SeO4 have been studied by calorimetry, impedance spectroscopy and X-ray powder diffraction. As synthesized, Rb2SeO4 includes a second phase of Rb2SeO3, which can be eliminated upon heating the compound. As expected, no conductivity is observed in dry (pH2O ....001 bar) air. By changing to humidified (pH2O = 0.1 bar) air at 176 deg. C, the conductivity increases sharply from 8.6·10-8 to 1.7·10-6 S cm-1. Under humidified (pH2O = 0.1 bar) reducing atmosphere (9%H2 in N2), the conductivity increases to 2.0·10-4 S cm-1 at 317 C. Degradation of Rb2SeO3 and Rb2SeO4...

  3. The effects of passive humidifier dead space on respiratory variables in paralyzed and spontaneously breathing patients.

    Science.gov (United States)

    Campbell, R S; Davis, K; Johannigman, J A; Branson, R D

    2000-03-01

    Passive humidifiers have gained acceptance in the intensive care unit because of their low cost, simple operation, and elimination of condensate from the breathing circuit. However, the additional dead space of these devices may adversely affect respiratory function in certain patients. This study evaluates the effects of passive humidifier dead space on respiratory function. Two groups of patients were studied. The first group consisted of patients recovering from acute lung injury and breathing spontaneously on pressure support ventilation. The second group consisted of patients who were receiving controlled mechanical ventilation and were chemically paralyzed following operative procedures. All patients used 3 humidification devices in random order for one hour each. The devices were a heated humidifier (HH), a hygroscopic heat and moisture exchanger (HHME) with a dead space of 28 mL, and a heat and moisture exchanger (HME) with a dead space of 90 mL. During each measurement period the following were recorded: tidal volume, minute volume, respiratory frequency, oxygen consumption, carbon dioxide production, ratio of dead space volume to tidal volume (VD/VT), and blood gases. In the second group, intrinsic positive end-expiratory pressure was also measured. Addition of either of the passive humidifiers was associated with increased VD/VT. In spontaneously breathing patients, VD/VT increased from 59 +/- 13 (HH) to 62 +/- 13 (HHME) to 68 +/- 11% (HME) (p < 0.05). In these patients, constant alveolar ventilation was maintained as a result of increased respiratory frequency, from 22.1 +/- 6.6 breaths/min (HH) to 24.5 +/- 6.9 breaths/min (HHME) to 27.7 +/- 7.4 breaths/min (HME) (p < 0.05), and increased minute volume, from 9.1 +/- 3.5 L/min (HH) to 9.9 +/- 3.6 L/min (HHME) to 11.7 +/- 4.2 L/min (HME) (p < 0.05). There were no changes in blood gases or carbon dioxide production. In the paralyzed patient group, VD/VT increased from 54 +/- 12% (HH) to 56 +/- 10% (HHME

  4. Inhomogeneity Based Characterization of Distribution Patterns on the Plasma Membrane.

    Directory of Open Access Journals (Sweden)

    Laura Paparelli

    2016-09-01

    Full Text Available Cell surface protein and lipid molecules are organized in various patterns: randomly, along gradients, or clustered when segregated into discrete micro- and nano-domains. Their distribution is tightly coupled to events such as polarization, endocytosis, and intracellular signaling, but challenging to quantify using traditional techniques. Here we present a novel approach to quantify the distribution of plasma membrane proteins and lipids. This approach describes spatial patterns in degrees of inhomogeneity and incorporates an intensity-based correction to analyze images with a wide range of resolutions; we have termed it Quantitative Analysis of the Spatial distributions in Images using Mosaic segmentation and Dual parameter Optimization in Histograms (QuASIMoDOH. We tested its applicability using simulated microscopy images and images acquired by widefield microscopy, total internal reflection microscopy, structured illumination microscopy, and photoactivated localization microscopy. We validated QuASIMoDOH, successfully quantifying the distribution of protein and lipid molecules detected with several labeling techniques, in different cell model systems. We also used this method to characterize the reorganization of cell surface lipids in response to disrupted endosomal trafficking and to detect dynamic changes in the global and local organization of epidermal growth factor receptors across the cell surface. Our findings demonstrate that QuASIMoDOH can be used to assess protein and lipid patterns, quantifying distribution changes and spatial reorganization at the cell surface. An ImageJ/Fiji plugin of this analysis tool is provided.

  5. Preparation and Characterization of Lignin-based Membrane Material

    Directory of Open Access Journals (Sweden)

    Shuai Wang

    2015-07-01

    Full Text Available Lignin-based membrane material was prepared from lignosulfonate extracted from sulfite pulping. The effects of formaldehyde, polyvinyl alcohol (PVA, urea, borax, glutaraldehyde (GD, and dimethyl phthalate (DMP on tensile strength and water absorption were investigated. The experimental results showed that the optimum conditions were as follows: a reaction temperature of 85 °C, 22.22 wt.% lignosulfonate, 1.59 wt.% borax, 22.22 wt.% urea, 31.75 wt.% formaldehyde, 22.22 wt.% PVA, 32.32 wt.% GD (to PVA glue, and 32.32 wt.% DMP (to PVA glue. Under these conditions, the tensile strength reached 2.2 ×104 Pa and the water absorption was 35.2%. The products were characterized by Fourier transform infrared spectroscopy (FTIR and scanning electron microscopy (SEM. The results showed that the product components were compatible in this system, and the introduction of cross-linking agents may have resulted in a decrease in pore size.

  6. Solar assisted liquid desiccant cooling using clay based membranes

    Directory of Open Access Journals (Sweden)

    Priya S. Shanmuga

    2018-01-01

    Full Text Available The environmental concerns have led to the urge of the usage of non-conventional energy resources like solar, wind, thermal, geothermal etc. which provide enormous source of energy without causing any further diminution of the environment. Instead of the conventional HVAC systems that cause colossal environmental perils, usage of liquid desiccants in coming in vogue whereby reducing ecological threats. Moreover, solar assisted systems provide further impulse to such systems. This paper discusses about the various comparisons between liquid desiccants: Lithium chloride, Potassium formate and Calcium chloride and concludes that potassium formate is the best desiccant to be used among the three. Potassium formate (HCOOK is used which is cheaper and less corrosive as compared to the other aqueous salts, and has a negative crystallization temperature. Potassium formate is a new liquid desiccant and thus, not much research is available currently. The weather conditions of Manipal provide an appropriate condition for the experimentations of solar aided liquid desiccant evaporative cooling systems due to its humid climate and intense solar radiation obtained. The small scale experimentation also encounters the problem of liquid desiccant carryover by the air flow, with the help of clay based membranes which are again cheap, environmentally benign and obtained in a facile way. The projected system takes complete advantage of pure solar energy aimed at the regeneration of liquid desiccant.

  7. Biomaterials based on photosynthetic membranes as potential sensors for herbicides.

    Science.gov (United States)

    Ventrella, Andrea; Catucci, Lucia; Placido, Tiziana; Longobardi, Francesco; Agostiano, Angela

    2011-08-15

    In this study, ultrathin film multilayers of Photosystem II-enriched photosynthetic membranes (BBY) were prepared and immobilized on quartz substrates by means of a Layer by Layer procedure exploiting electrostatic interactions with poly(ethylenimine) as polyelectrolyte. The biomaterials thus obtained were characterized by means of optical techniques and Atomic Force Microscopy, highlighting the fact that the Layer by Layer approach allowed the BBYs to be immobilized with satisfactory results. The activity of these hybrid materials was evaluated by means of optical assays based on the Hill Reaction, indicating that the biosamples, which preserved about 65% of their original activity even ten weeks after preparation, were both stable and active. Furthermore, an investigation of the biochips' sensitivity to the herbicide terbutryn, as a model analyte, gave interesting results: inhibition of photosynthetic activity was observed at terbutryn concentrations higher than 10(-7)M, thus evidencing the potential of such biomaterials in the environmental biosensor field. Copyright © 2011 Elsevier B.V. All rights reserved.

  8. Morin-based nanofiltration membranes for organic solvent separation processes

    KAUST Repository

    Perez Manriquez, Liliana; Neelakanda, Pradeep; Peinemann, Klaus-Viktor

    2018-01-01

    In this work we demonstrate the successful optimization of the interfacial polymerization reaction for the manufacture of organic solvent nanofiltration membranes by replacing the toxic amines commonly used for this method with the natural occurring

  9. Morin-based nanofiltration membranes for organic solvent separation processes

    KAUST Repository

    Perez Manriquez, Liliana

    2018-02-26

    In this work we demonstrate the successful optimization of the interfacial polymerization reaction for the manufacture of organic solvent nanofiltration membranes by replacing the toxic amines commonly used for this method with the natural occurring bio-polyphenol morin. For the manufacture of this type of OSN membrane a crosslinked PAN support was coated by interfacial polymerization using morin as the monomer of the aqueous phase and terephtaloyl chloride as the monomer of the organic phase. These membranes showed an exceptional performance and resistance to NMP by having a a permeance of 0.3L/m2 h bar in NMP with a rejection of 96% of Brilliant Blue dye which has a molecular weight of 825.97g/mol, making these membranes attractive for harsh industrial separation processes due to their ease of manufacture, low cost, and excellent performance.

  10. The Role of Heated Humidified High-flow Nasal Cannula as Noninvasive Respiratory Support in Neonates

    Directory of Open Access Journals (Sweden)

    Ke-Yun Chao

    2017-08-01

    Full Text Available Recently, heated humidified high-flow nasal cannula (HHHFNC has been introduced and applied as a noninvasive respiratory support in neonates. Although HHHFNC is widely used in neonates presenting with respiratory distress, the efficiency and safety when compared with nasal continuous positive airway pressure or noninvasive positive pressure ventilation are still controversial. This review aims to evaluate the performance and applications of HHHFNC in neonates.

  11. By-Product Carrying Humidified Hydrogen: An Underestimated Issue in the Hydrolysis of Sodium Borohydride.

    Science.gov (United States)

    Petit, Eddy; Miele, Philippe; Demirci, Umit B

    2016-07-21

    Catalyzed hydrolysis of sodium borohydride generates up to four molecules of hydrogen, but contrary to what has been reported so far, the humidified evolved gas is not pure hydrogen. Elemental and spectroscopic analyses show, for the first time, that borate by-products pollute the stream as well as the vessel. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Process intensification on membrane-based process for blackcurrant juice concentration

    DEFF Research Database (Denmark)

    Fjerbæk Søtoft, Lene; Rong, Ben-Guang; Christensen, Knud Villy

    Juice concentrate production is a field where process intensification and novel concentration processes need to be implemented. The paper presents a systematic approach for process synthesis based on membrane processes for the concentration of blackcurrant juice, exemplified by the aroma recovery...... using combinations of vacuum membrane distillation and traditional distillation. Furthermore, the paper further suggests a novel method for the combination of nanofiltration, reverse osmosis and membrane distillation for the concentration of the dearomatized juice....

  13. High-performance membrane electrode assembly with multi-functional Pt/SnO2eSiO2/C catalyst for proton exchange membrane fuel cell operated under low-humidity conditions

    CSIR Research Space (South Africa)

    Hou, S

    2016-06-01

    Full Text Available A novel self-humidifying membrane electrode assembly (MEA) with homemade multifunctional Pt/SnO(sub2)-SiO(sub2)/C as the anode was developed to improve the performance of a proton exchange membrane fuel cell under low humidity. The MEAs' performance...

  14. Effect of MWCNT Filler on Properties and Flux of Chitosan/ PEG based Nanocomposites Membranes

    Directory of Open Access Journals (Sweden)

    Khoerunnisa Fitri

    2018-01-01

    Full Text Available Biopolymer are expected to be environmentally compatible and to have great potential application as membranes material. The chitosan-poly (ethylene glycol/PEG based composite membranes was successfully synthesized via inversed phase method. The effect of multiwalled carbon nanotubes (MWCNT as nanofiller on properties and performances of composite membranes were intensively evaluated. The membrane was prepared by mixing of chitosan and PEG solutions at the same composition ratio while MWCNT amount in the mixture was varied. The synthesized membrane was characterized by means of FTIR spectroscopy, scanning electron microscopy (SEM, contact angle, and tensile strength measurement. The performance of composite membrane on filtration was evaluated in term of flux (permeability and rejection (rejection tests. The results showed that the optimum volume ratio of composite membrane solution was found at 30:10:7.5 for chitosan/ PEG/ MWCNT, respectively, as indicated by the largest flux. Insertion of MWCNT nanofiller notably enhanced hydrophilicity, porosity, and mechanical properties of composites membranes that are confirmed by contact angle, SEM images and elongation forces value, respectively. The MWCNT nanofiller remarkably increased both of flux and rejection of composite membranes up to 60 Lm2h-1 and 96%, respectively. The remarkable enhancement of composite membrane performance is attributed to the effective interaction of MWCNT with polymeric matrix.

  15. Use of Normothermic Default Humidifier Settings Causes Excessive Humidification of Respiratory Gases During Therapeutic Hypothermia.

    Science.gov (United States)

    Tanaka, Shoichiro; Iwata, Sachiko; Kinoshita, Masahiro; Tsuda, Kennosuke; Sakai, Sayaka; Saikusa, Mamoru; Shindo, Ryota; Harada, Eimei; Okada, Junichiro; Hisano, Tadashi; Kanda, Hiroshi; Maeno, Yasuki; Araki, Yuko; Ushijima, Kazuo; Sakamoto, Teruo; Yamashita, Yushiro; Iwata, Osuke

    2016-12-01

    Adult patients frequently suffer from serious respiratory complications during therapeutic hypothermia. During therapeutic hypothermia, respiratory gases are humidified close to saturated vapor at 37°C (44 mg/L) despite that saturated vapor reduces considerably depending on temperature reduction. Condensation may cause serious adverse events, such as bronchial edema, mucosal dysfunction, and ventilator-associated pneumonia during cooling. To determine clinical variables associated with inadequate humidification of respiratory gases during cooling, humidity of inspiratory gases was measured in 42 cumulative newborn infants who underwent therapeutic hypothermia. Three humidifier settings of 37-default (chamber outlet, 37°C; distal circuit, 40°C), 33.5-theoretical (chamber outlet, 33.5°C; distal circuit, 36.5°C), and 33.5-adjusted (optimized setting to achieve 36.6 mg/L using feedback from a hygrometer) were tested to identify independent variables of excessively high humidity >40.7 mg/L and low humidity <32.9 mg/L. The mean (SD) humidity at the Y-piece was 39.2 (5.2), 33.3 (4.1), and 36.7 (1.2) mg/L for 37-default, 33.5-theoretical, and 33.5-adjusted, respectively. The incidence of excessive high humidity was 10.3% (37-default, 31.0%; 33.5-theoretical, 0.0%; 33.5-adjusted, 0.0%), which was positively associated with the use of a counter-flow humidifier (p < 0.001), 37-default (compared with 33.5-theoretical and 33.5-adjusted, both p < 0.001) and higher fraction of inspired oxygen (p = 0.003). The incidence of excessively low humidity was 17.5% (37-default, 7.1%; 33.5-theoretical, 45.2%; 33.5-adjusted, 0.0%), which was positively associated with the use of a pass-over humidifier and 33.5-theoretical (both p < 0.001). All patients who used a counter-flow humidifier achieved the target gas humidity at the Y-piece (36.6 ± 0.5 mg/L) required for 33.5-adjusted with 33.5-theoretical. During cooling, 37-default is associated with

  16. Water hyacinth cellulose-based membrane for adsorption of liquid waste dyes and chromium

    Science.gov (United States)

    Agtasia Putri, Cintia; Yulianti, Ian; Desianna, Ika; Sholihah, Anisa; Sujarwata

    2018-04-01

    Water hyacinth (Eichornia crassipes) is a weed in aquatic area whose trunk contains a lot of cellulose. Cellulose contained can be used as dyes adsorbent in a form of composite membrane. This study aims to investigate the capacity of water hyacinth cellulose-based membrane to adsorb dye and Chromium (Cr) contained in liquid. The process of membrane fabrication begins with isolation of water hyacinth cellulose. The isolated cellulose powder was used to make the membrane by mixing it with polyvinyl alcohol-polyethylene glycol (PVA-PEG) with various compositions. The morphology of membrane surface was analyzed using CCD microscope. The analysis using Ultraviolet Visible Spectroscopy (UV-Vis) and Atomic Absorption Spectroscopy (AAS) indicate that the membrane with composition ratio of cellulose: PVA: PEG of 6.5: 2.5: 1 adsorb Cr up to 38.75%.

  17. Magnetic properties of the magnetic hybrid membranes based on various polymer matrices and inorganic fillers

    International Nuclear Information System (INIS)

    Rybak, Aleksandra; Kaszuwara, Waldemar

    2015-01-01

    Magnetic hybrid membranes based on ethylcellulose (EC), poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) and various magnetic praseodymium and neodymium powder microparticles as fillers were obtained. Permeability, diffusion and sorption coefficients of O 2 , N 2 and synthetic air components were estimated for homogeneous and heterogeneous membranes using the Time Lag method based on constant pressure permeation technique. The microstructure studies and the phase analysis of magnetic membranes were also performed using SEM and XRD. The influence of magnetic parameters, like coercivity, remanence and saturation magnetization of created membranes on the gas transport properties was studied. The results showed that their coercivity depended on composition and microstructure of the magnetic powder. On the other hand, remanence and saturation magnetization increased with the increase of the powder addition in the membrane. It was found that the magnetic membrane's gas transport properties were improved with the increase of membrane's remanence, saturation magnetization and magnetic particle filling. The decrease in powder particle size and associated increase of the membrane's coercivity also positively influenced the gas transport and separation properties of investigated membranes. It was observed that the magnetic ethylcellulose and poly(2,6-dimethyl-1,4-phenylene oxide) membranes had higher gas permeability, while their permselectivity and solubility coefficient values were rather maintained or slightly increased. The results also showed that the magnetic powder content enhanced significantly gas diffusivity in EC and PPO membranes. It was also analyzed the dependence of the drift coefficient w on the magnetic parameters of investigated membranes. The correlation between the membrane selectivity, permeability and magnetic properties with their XRD characteristics was stated. - Highlights: • Membrane's production consisting of EC or PPO polymers and

  18. Magnetic properties of the magnetic hybrid membranes based on various polymer matrices and inorganic fillers

    Energy Technology Data Exchange (ETDEWEB)

    Rybak, Aleksandra, E-mail: Aleksandra.Rybak@polsl.pl [Department of Physical Chemistry and Technology of Polymers, Faculty of Chemistry, Silesian University of Technology, Strzody 9, 44-100 Gliwice (Poland); Kaszuwara, Waldemar [Faculty of Materials Science and Engineering, Warsaw University of Technology, Woloska 141, 02-507 Warszawa (Poland)

    2015-11-05

    Magnetic hybrid membranes based on ethylcellulose (EC), poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) and various magnetic praseodymium and neodymium powder microparticles as fillers were obtained. Permeability, diffusion and sorption coefficients of O{sub 2}, N{sub 2} and synthetic air components were estimated for homogeneous and heterogeneous membranes using the Time Lag method based on constant pressure permeation technique. The microstructure studies and the phase analysis of magnetic membranes were also performed using SEM and XRD. The influence of magnetic parameters, like coercivity, remanence and saturation magnetization of created membranes on the gas transport properties was studied. The results showed that their coercivity depended on composition and microstructure of the magnetic powder. On the other hand, remanence and saturation magnetization increased with the increase of the powder addition in the membrane. It was found that the magnetic membrane's gas transport properties were improved with the increase of membrane's remanence, saturation magnetization and magnetic particle filling. The decrease in powder particle size and associated increase of the membrane's coercivity also positively influenced the gas transport and separation properties of investigated membranes. It was observed that the magnetic ethylcellulose and poly(2,6-dimethyl-1,4-phenylene oxide) membranes had higher gas permeability, while their permselectivity and solubility coefficient values were rather maintained or slightly increased. The results also showed that the magnetic powder content enhanced significantly gas diffusivity in EC and PPO membranes. It was also analyzed the dependence of the drift coefficient w on the magnetic parameters of investigated membranes. The correlation between the membrane selectivity, permeability and magnetic properties with their XRD characteristics was stated. - Highlights: • Membrane's production consisting of EC or PPO

  19. Aquaporin based biomimetic membrane in forward osmosis: Chemical cleaning resistance and practical operation

    KAUST Repository

    Li, Zhenyu

    2017-07-27

    Aquaporin plays a promising role in fabricating high performance biomimetic forward osmosis (FO) membranes. However, aquaporin as a protein also has a risk of denaturation caused by various chemicals, resulting in a possible decay of membrane performance. The present study tested a novel aquaporin based biomimetic membrane in simulated membrane cleaning processes. The effects of cleaning agents on water flux and salt rejection were evaluated. The membrane showed a good resistance to the chemical agents. The water flux after chemical cleaning showed significant increases, particularly after cleaning with NaOCl and Alconox. Changes in the membrane structure and increased hydrophilicity in the surrounding areas of the aquaporin may be accountable for the increase in water permeability. The membrane shows stable salt rejection up to 99% after all cleaning agents were tested. A 15-day experiment with secondary wastewater effluent as the feed solution and seawater as the draw solution showed a stable flux and high salt rejection. The average rejection of the dissolved organic carbon from wastewater after the 15-day test was 90%. The results demonstrated that the aquaporin based biomimetic FO membrane exhibits chemical resistance for most agents used in membrane cleaning procedures, maintaining a stable flux and high salt rejection.

  20. Aquaporin based biomimetic membrane in forward osmosis: Chemical cleaning resistance and practical operation

    KAUST Repository

    Li, Zhenyu; Valladares Linares, Rodrigo; Bucs, Szilard; Fortunato, Luca; Hé lix-Nielsen, Claus; Vrouwenvelder, Johannes S.; Ghaffour, NorEddine; Leiknes, TorOve; Amy, Gary

    2017-01-01

    Aquaporin plays a promising role in fabricating high performance biomimetic forward osmosis (FO) membranes. However, aquaporin as a protein also has a risk of denaturation caused by various chemicals, resulting in a possible decay of membrane performance. The present study tested a novel aquaporin based biomimetic membrane in simulated membrane cleaning processes. The effects of cleaning agents on water flux and salt rejection were evaluated. The membrane showed a good resistance to the chemical agents. The water flux after chemical cleaning showed significant increases, particularly after cleaning with NaOCl and Alconox. Changes in the membrane structure and increased hydrophilicity in the surrounding areas of the aquaporin may be accountable for the increase in water permeability. The membrane shows stable salt rejection up to 99% after all cleaning agents were tested. A 15-day experiment with secondary wastewater effluent as the feed solution and seawater as the draw solution showed a stable flux and high salt rejection. The average rejection of the dissolved organic carbon from wastewater after the 15-day test was 90%. The results demonstrated that the aquaporin based biomimetic FO membrane exhibits chemical resistance for most agents used in membrane cleaning procedures, maintaining a stable flux and high salt rejection.

  1. Carbon Molecular Sieve Membranes Derived from Tröger's Base-Based Microporous Polyimide for Gas Separation.

    Science.gov (United States)

    Wang, Zhenggong; Ren, Huiting; Zhang, Shenxiang; Zhang, Feng; Jin, Jian

    2018-03-09

    Carbon molecular sieve (CMS)-based membranes have attracted great attention because of their outstanding gas-separation performance. The polymer precursor is a key point for the preparation of high-performance CMS membranes. In this work, a microporous polyimide precursor containing a Tröger's base unit was used for the first time to prepare CMS membranes. By optimizing the pyrolysis procedure and the soaking temperature, three TB-CMS membranes were obtained. Gas-permeation tests revealed that the comprehensive gas-separation performance of the TB-CMS membranes was greatly enhanced relative to that of most state-of-the-art CMS membranes derived from polyimides reported so far. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Thermally rearranged (TR) bismaleimide-based network polymers for gas separation membranes.

    Science.gov (United States)

    Do, Yu Seong; Lee, Won Hee; Seong, Jong Geun; Kim, Ju Sung; Wang, Ho Hyun; Doherty, Cara M; Hill, Anita J; Lee, Young Moo

    2016-11-15

    Highly permeable, thermally rearranged polymer membranes based on bismaleimide derivatives that exhibit excellent CO 2 permeability up to 5440 Barrer with a high BET surface area (1130 m 2 g -1 ) are reported for the first time. In addition, the membranes can be easily used to form semi-interpenetrating networks with other polymers endowing them with superior gas transport properties.

  3. Novel crosslinked membranes based on sulfonated poly(ether ether ketone) for direct methanol fuel cells.

    Science.gov (United States)

    Zhu, Yuanqin; Zieren, Shelley; Manthiram, Arumugam

    2011-07-14

    Novel covalently crosslinked membranes based on sulfonated poly(ether ether ketone) and carboxylated polysulfone exhibit much lower methanol crossover and better performance in direct methanol fuel cells at 65 °C in 1 and 2 M methanol solutions compared to Nafion 115 membranes.

  4. Membrane-based ethylene/ethane separation: The upper bound and beyond

    KAUST Repository

    Rungta, Meha

    2013-08-02

    Ethylene/ethane separation via cryogenic distillation is extremely energy-intensive, and membrane separation may provide an attractive alternative. In this paper, ethylene/ethane separation performance using polymeric membranes is summarized, and an experimental ethylene/ethane polymeric upper bound based on literature data is presented. A theoretical prediction of the ethylene/ethane upper bound is also presented, and shows good agreement with the experimental upper bound. Further, two ways to overcome the ethylene/ethane upper bound, based on increasing the sorption or diffusion selectivity, is also discussed, and a review on advanced membrane types such as facilitated transport membranes, zeolite and metal organic framework based membranes, and carbon molecular sieve membranes is presented. Of these, carbon membranes have shown the potential to surpass the polymeric ethylene/ethane upper bound performance. Furthermore, a convenient, potentially scalable method for tailoring the performance of carbon membranes for ethylene/ethane separation based on tuning the pyrolysis conditions has also been demonstrated. © 2013 American Institute of Chemical Engineers.

  5. Field testing of polymeric mesh and ash-based ceramic membranes ...

    African Journals Online (AJOL)

    This paper presents the initial findings of field testing of 2 low-cost membrane filters, viz. 30 ìm polymeric mesh and 2–6 ìm macroporous waste-ash based ceramic filter, in a submerged membrane bioreactor (MBR) employing batch anoxic and aerobic conditions. The influent was raw wastewater from a residential complex ...

  6. Protective clothing based on permselective membrane and carbon adsorption

    International Nuclear Information System (INIS)

    Gottschlich, D.; Baker, R.

    1995-01-01

    This paper is a description of Phase I of the US DOE's program to develop improved protective clothing for use by workers engaged in decommissioning and decontamination of former DOE sites, including those used for atomic weapons research and production. Membrane Technology and Research has been developing the clothing with an innovative feature of an ultrathin, permselective outer membrane that is extremely permeable to water but impermeable to toxic organic compounds. Phase I (as described herein) includes fabric optimization, commercial-scale fabric production, and prototype suit evaluation. This phase is complete, with the results discussed in this document

  7. Carbon nanotubes based nafion composite membranes for fuel cell applications

    CSIR Research Space (South Africa)

    Cele, NP

    2009-01-01

    Full Text Available Carbon nanotubes (CNTs) containing Nafion composite membranes were prepared via melt-blending at 250 °C. Using three different types of CNTs such as pure CNTs (pCNTs), oxidised CNTs (oCNTs) and amine functionalised CNTs (fCNTs); the effect of CNTs...

  8. Polyether based block copolymer membranes for CO2 separation

    NARCIS (Netherlands)

    Reijerkerk, Sander

    2010-01-01

    The work described in this thesis is dedicated to the development of polymeric membrane materials for the separation of CO2 from light gases, and in particular to the separation of CO2 from nitrogen as required in a post-combustion capture conguration for the separation of CO2 from flue gases. An

  9. Novel proton exchange membrane based on crosslinked poly(vinyl alcohol) for direct methanol fuel cells

    Science.gov (United States)

    Liu, Chien-Pan; Dai, Chi-An; Chao, Chi-Yang; Chang, Shoou-Jinn

    2014-03-01

    In this study, we report the synthesis and the characterization of poly (vinyl alcohol) based proton conducting membranes. In particular, we describe a novel physically and chemically PVA/HFA (poly (vinyl alcohol)/hexafluoroglutaric acid) blending membranes with BASANa (Benzenesulfonic acid sodium salt) and GA (Glutaraldehyde) as binary reaction agents. The key PEM parameters such as ion exchange capacity (IEC), water uptake, proton conductivity, and methanol permeability were controlled by adjusting the chemical composition of the membranes. The IEC value of the membrane is found to be an important parameter in affecting water uptake, conductivity as well as the permeability of the resulting membrane. Plots of the water uptake, conductivity, and methanol permeability vs. IEC of the membranes show a distinct change in the slope of their curves at roughly the same IEC value which suggests a transition of structural changes in the network. The proton conductivities and the methanol permeability of all the membranes are in the range of 10-3-10-2 S cm-1 and 10-8-10-7 cm2 s-1, respectively, depending on its binary crosslinking density, and it shows great selectivity compared with those of Nafion®-117. The membranes display good mechanical properties which suggest a good lifetime usage of the membranes applied in DMFCs.

  10. Silver nanoparticles delivery system based on natural rubber latex membranes

    International Nuclear Information System (INIS)

    Guidelli, Éder José; Kinoshita, Angela; Ramos, Ana Paula; Baffa, Oswaldo

    2013-01-01

    The search for new materials for biomedical applications is extremely important. Here, we present results on the performance of a silver nanoparticles delivery system using natural rubber latex (NRL) as the polymeric matrix. Our aim was to obtain an optimized wound dressing by combining materials with potential healing action. The synthesis of silver nanoparticles and their characterization by UV–Vis spectroscopy, transmission electron microscopy, zeta potential, dynamic light scattering, and Fourier transform infrared spectroscopy (FTIR) are depicted. The NRL membranes are good matrix for silver nanoparticles and allow for their gradual release. The release of 30 nm silver nanoparticles by the NRL membranes depends on their mass percentage in NRL membranes. The total concentration of AgNP released by the NRL membranes was calculated. The AgNP attached to the cis-isoprene molecules in the NRL matrix remain attached to the membrane (∼0.1 % w/w). So, only the AgNP bound to the non-rubber molecules are released. FTIR spectra suggest that non-rubber molecules, like aminoacids and proteins, associated with the serum fraction of the NRL may be attached to the surfaces of the released nanoparticles, thereby increasing the release of such molecules. The released silver nanoparticles are sterically stabilized, more stable and well dispersed. Because the serum fraction of the NRL is responsible for the angiogenic properties of the matrix, the silver nanoparticles could increment the angiogenic properties of NRL. This biomaterial has desirable properties for the fabrication of a wound dressing with potential healing action, since it combines the angiogenic and antibacterial properties of the silver nanoparticles with the increased angiogenic properties of the NRL.Graphical AbstractThe AgNP attached to the cis-isoprene molecules remain in the NRL matrix and only the AgNP bound to the non-rubber molecules (NRL serum fraction) are released. The released AgNP are sterically

  11. Silver nanoparticles delivery system based on natural rubber latex membranes

    Energy Technology Data Exchange (ETDEWEB)

    Guidelli, Eder Jose, E-mail: ederguidelli@gmail.com [Universidade de Sao Paulo/FFCLRP-DF (Brazil); Kinoshita, Angela [Universidade do Sagrado Coracao (Brazil); Ramos, Ana Paula [Universidade de Sao Paulo/FFCLRP-DQ (Brazil); Baffa, Oswaldo [Universidade de Sao Paulo/FFCLRP-DF (Brazil)

    2013-04-15

    The search for new materials for biomedical applications is extremely important. Here, we present results on the performance of a silver nanoparticles delivery system using natural rubber latex (NRL) as the polymeric matrix. Our aim was to obtain an optimized wound dressing by combining materials with potential healing action. The synthesis of silver nanoparticles and their characterization by UV-Vis spectroscopy, transmission electron microscopy, zeta potential, dynamic light scattering, and Fourier transform infrared spectroscopy (FTIR) are depicted. The NRL membranes are good matrix for silver nanoparticles and allow for their gradual release. The release of 30 nm silver nanoparticles by the NRL membranes depends on their mass percentage in NRL membranes. The total concentration of AgNP released by the NRL membranes was calculated. The AgNP attached to the cis-isoprene molecules in the NRL matrix remain attached to the membrane ({approx}0.1 % w/w). So, only the AgNP bound to the non-rubber molecules are released. FTIR spectra suggest that non-rubber molecules, like aminoacids and proteins, associated with the serum fraction of the NRL may be attached to the surfaces of the released nanoparticles, thereby increasing the release of such molecules. The released silver nanoparticles are sterically stabilized, more stable and well dispersed. Because the serum fraction of the NRL is responsible for the angiogenic properties of the matrix, the silver nanoparticles could increment the angiogenic properties of NRL. This biomaterial has desirable properties for the fabrication of a wound dressing with potential healing action, since it combines the angiogenic and antibacterial properties of the silver nanoparticles with the increased angiogenic properties of the NRL.Graphical AbstractThe AgNP attached to the cis-isoprene molecules remain in the NRL matrix and only the AgNP bound to the non-rubber molecules (NRL serum fraction) are released. The released AgNP are

  12. Effect of sintering temperature on the morphology and mechanical properties of PTFE membranes as a base substrate for proton exchange membrane

    Directory of Open Access Journals (Sweden)

    Nor Aida Zubir

    2002-11-01

    Full Text Available This paper reports the development of PTFE membranes as the base substrates for producing proton exchange membrane by using radiation-grafting technique. An aqueous dispersion of PTFE, which includes sodium benzoate, is cast in order to form suitable membranes. The casting was done by usinga pneumatically controlled flat sheet membrane-casting machine. The membrane is then sintered to fuse the polymer particles and cooled. After cooling process, the salt crystals are leached from the membrane by dissolution in hot bath to leave a microporous structure, which is suitable for such uses as a filtration membrane or as a base substrate for radiation grafted membrane in PEMFC. The effects of sintering temperature on the membrane morphology and tensile strength were investigated at 350oC and 385oC by using scanning electron microscopy (SEM and EX 20, respectively. The pore size and total void space are significantly smaller at higher sintering temperature employed with an average pore diameter of 11.78 nm. The tensile strength and tensile strain of sintered PTFE membrane at 385oC are approximately 19.02 + 1.46 MPa and 351.04 + 23.13 %, respectively. These results were indicated at 385oC, which represents significant improvements in tensile strength and tensile strain, which are nearly twice those at 350oC.

  13. Leucine-based receptor sorting motifs are dependent on the spacing relative to the plasma membrane

    DEFF Research Database (Denmark)

    Geisler, C; Dietrich, J; Nielsen, B L

    1998-01-01

    Many integral membrane proteins contain leucine-based motifs within their cytoplasmic domains that mediate internalization and intracellular sorting. Two types of leucine-based motifs have been identified. One type is dependent on phosphorylation, whereas the other type, which includes an acidic...... amino acid, is constitutively active. In this study, we have investigated how the spacing relative to the plasma membrane affects the function of both types of leucine-based motifs. For phosphorylation-dependent leucine-based motifs, a minimal spacing of 7 residues between the plasma membrane...... and the phospho-acceptor was required for phosphorylation and thereby activation of the motifs. For constitutively active leucine-based motifs, a minimal spacing of 6 residues between the plasma membrane and the acidic residue was required for optimal activity of the motifs. In addition, we found that the acidic...

  14. Interactions of sugar-based bolaamphiphiles with biomimetic systems of plasma membranes.

    Science.gov (United States)

    Nasir, Mehmet Nail; Crowet, Jean-Marc; Lins, Laurence; Obounou Akong, Firmin; Haudrechy, Arnaud; Bouquillon, Sandrine; Deleu, Magali

    2016-11-01

    Glycolipids constitute a class of molecules with various biological activities. Among them, sugar-based bolaamphiphiles characterized by their biocompatibility, biodegradability and lower toxicity, became interesting for the development of efficient and low cost lipid-based drug delivery systems. Their activity seems to be closely related to their interactions with the lipid components of the plasma membrane of target cells. Despite many works devoted to the chemical synthesis and characterization of sugar-based bolaamphiphiles, their interactions with plasma membrane have not been completely elucidated. In this work, two sugar-based bolaamphiphiles differing only at the level of their sugar residues were chemically synthetized. Their interactions with membranes have been investigated using model membranes containing or not sterol and with in silico approaches. Our findings indicate that the nature of sugar residues has no significant influence for their membrane interacting properties, while the presence of sterol attenuates the interactions of both bolaamphiphiles with the membrane systems. The understanding of this distinct behavior of bolaamphiphiles towards sterol-containing membrane systems could be useful for their applications as drug delivery systems. Copyright © 2016. Published by Elsevier B.V.

  15. New Highly-Sensitive Methods for Electroanalytical Chemistry Based on Nanotubule Membranes

    National Research Council Canada - National Science Library

    Kobayashi, Yoshio

    1999-01-01

    Two new methods of electroanalysis are described. These methods are based on membranes containing monodisperse Au nanotubules with inside diameters approaching molecular dimensions (approx. 1 to approx. 3 nm...

  16. Nonlinear Lyapunov-based boundary control of distributed heat transfer mechanisms in membrane distillation plant

    KAUST Repository

    Eleiwi, Fadi; Laleg-Kirati, Taous-Meriem

    2015-01-01

    This paper presents a nonlinear Lyapunov-based boundary control for the temperature difference of a membrane distillation boundary layers. The heat transfer mechanisms inside the process are modeled with a 2D advection-diffusion equation. The model

  17. Samarium (III Selective Membrane Sensor Based on Tin (IV Boratophosphate

    Directory of Open Access Journals (Sweden)

    Ashok S. K. Kumar

    2004-08-01

    Full Text Available Abstract: A number of Sm (III selective membranes of varying compositions using tin (IV boratophosphate as electroactive material were prepared. Polyvinyl chloride, polystyrene and epoxy resin were used as binding materials. Membrane having composition of 40% exchanger and 60% epoxy resin exhibited best performance. This membrane worked well over a wide concentration range of 1x10-5M to 1x10-1 M of samarium ions with a Super-Nernstian slope of 40 mV/decade. It has a fast response time of less than 10 seconds and can be used for at least six months without any considerable divergence in potentials. The proposed sensor revealed good selectivities with respect to alkali, alkaline earth, some transition and rare earth metal ions and can be used in the pH range of 4.0-10.0. It was used as an indicator electrode in the potentiometric titration of Sm (III ions against EDTA. Effect of internal solution was studied and the electrode was successfully used in non-aqueous media, too.

  18. Tailored freestanding multilayered membranes based on chitosan and alginate.

    Science.gov (United States)

    Silva, Joana M; Duarte, Ana Rita C; Caridade, Sofia G; Picart, Catherine; Reis, Rui L; Mano, João F

    2014-10-13

    Engineering metabolically demanding tissues requires the supply of nutrients, oxygen, and removal of metabolic byproducts, as well as adequate mechanical properties. In this work, we propose the development of chitosan (CHIT)/alginate (ALG) freestanding membranes fabricated by layer-by-layer (LbL) assembly. CHIT/ALG membranes were cross-linked with genipin at a concentration of 1 mg·mL(-1) or 5 mg·mL(-1). Mass transport properties of glucose and oxygen were evaluated on the freestanding membranes. The diffusion of glucose and oxygen decreases with increasing cross-linking concentration. Mechanical properties were also evaluated in physiological-simulated conditions. Increasing cross-linking density leads to an increase of storage modulus, Young modulus, and ultimate tensile strength, but to a decrease in the maximum hydrostatic pressure. The in vitro biological performance demonstrates that cross-linked films are more favorable for cell adhesion. This work demonstrates the versatility and feasibility of LbL assembly to generate nanostructured constructs with tunable permeability, mechanical, and biological properties.

  19. Preparation of carbon quantum dots based high photostability luminescent membranes.

    Science.gov (United States)

    Zhao, Jinxing; Liu, Cui; Li, Yunchuan; Liang, Jiyuan; Liu, Jiyan; Qian, Tonghui; Ding, Jianjun; Cao, Yuan-Cheng

    2017-06-01

    Urethane acrylate (UA) was used to prepare carbon quantum dots (C-dots) luminescent membranes and the resultants were examined with FT-IR, mechanical strength, scanning electron microscope (SEM) and quantum yields (QYs). FT-IR results showed the polyurethane acrylate (PUA) prepolymer -C = C-vibration at 1101 cm -1 disappeared but there was strong vibration at1687cm -1 which was contributed from the-C = O groups in cross-linking PUA. Mechanical strength results showed that the different quantity of C-dots loadings and UV-curing time affect the strength. SEM observations on the cross-sections of the membranes are uniform and have no structural defects, which prove that the C-dots are compatible with the water-soluble PUA resin. The C-dot loading was increased from 0 to 1 g, the maximum tensile stress was nearly 2.67 MPa, but the tensile strain was decreased from 23.4% to 15.1% and 7.2% respectively. QYs results showed that the C-dots in the membrane were stable after 120 h continuous irradiation. Therefore, the C-dots photoluminescent film is the promising material for the flexible devices in the future applications. Copyright © 2016 John Wiley & Sons, Ltd.

  20. Structure-based membrane dome mechanism for Piezo mechanosensitivity.

    Science.gov (United States)

    Guo, Yusong R; MacKinnon, Roderick

    2017-12-12

    Mechanosensitive ion channels convert external mechanical stimuli into electrochemical signals for critical processes including touch sensation, balance, and cardiovascular regulation. The best understood mechanosensitive channel, MscL, opens a wide pore, which accounts for mechanosensitive gating due to in-plane area expansion. Eukaryotic Piezo channels have a narrow pore and therefore must capture mechanical forces to control gating in another way. We present a cryo-EM structure of mouse Piezo1 in a closed conformation at 3.7Å-resolution. The channel is a triskelion with arms consisting of repeated arrays of 4-TM structural units surrounding a pore. Its shape deforms the membrane locally into a dome. We present a hypothesis in which the membrane deformation changes upon channel opening. Quantitatively, membrane tension will alter gating energetics in proportion to the change in projected area under the dome. This mechanism can account for highly sensitive mechanical gating in the setting of a narrow, cation-selective pore. © 2017, Guo et al.

  1. Morphologies and separation characteristics of polyphenyl sulfone-based solvent resistant nanofiltration membranes: Effect of polymer concentration in casting solution and membrane pretreatment condition

    International Nuclear Information System (INIS)

    Sani, Nur Aimie Abdullah; Lau, Woei Jye; Ismail, Ahmad Fauzi

    2015-01-01

    The performance of polyphenylsulfone (PPSU) solvent resistant nanofiltration (SRNF)-based flat sheet membranes prepared from phase inversion method was investigated by varying the concentration of polymer in the dope solution and condition of membrane pretreatment process. The membrane properties were characterized by SEM, FTIR, AFM and contact angle goniometer, while their performance was evaluated by measuring methanol flux and rejection of different molecular weight of dyes (ranging from 269 to 1,470 g/mol) in methanol. The experimental results showed that the polymer concentration has great impact not only on the final membrane morphology but also its separation characteristics. Increasing polymer concentration from 17 to 25wt% tended to suppress finger-like structure and more pear-like pores were developed, causing methanol flux to decrease. This can be explained by the decrease in molecular weight cut off (MWCO) of the membrane prepared at high polymer concentration. With respect to the effect of membrane pretreatment conditions, the rejection of membrane was negatively affected with longer immersion period in methanol solution prior to filtration experiment. The variation in membrane rejection can be attributed to the rearrangement of the polymer chain, which results in membrane swelling and/or change of membrane surface hydrophilicity

  2. Morphologies and separation characteristics of polyphenyl sulfone-based solvent resistant nanofiltration membranes: Effect of polymer concentration in casting solution and membrane pretreatment condition

    Energy Technology Data Exchange (ETDEWEB)

    Sani, Nur Aimie Abdullah; Lau, Woei Jye; Ismail, Ahmad Fauzi [Universiti Teknologi Malaysia, Skudai (Malaysia)

    2015-04-15

    The performance of polyphenylsulfone (PPSU) solvent resistant nanofiltration (SRNF)-based flat sheet membranes prepared from phase inversion method was investigated by varying the concentration of polymer in the dope solution and condition of membrane pretreatment process. The membrane properties were characterized by SEM, FTIR, AFM and contact angle goniometer, while their performance was evaluated by measuring methanol flux and rejection of different molecular weight of dyes (ranging from 269 to 1,470 g/mol) in methanol. The experimental results showed that the polymer concentration has great impact not only on the final membrane morphology but also its separation characteristics. Increasing polymer concentration from 17 to 25wt% tended to suppress finger-like structure and more pear-like pores were developed, causing methanol flux to decrease. This can be explained by the decrease in molecular weight cut off (MWCO) of the membrane prepared at high polymer concentration. With respect to the effect of membrane pretreatment conditions, the rejection of membrane was negatively affected with longer immersion period in methanol solution prior to filtration experiment. The variation in membrane rejection can be attributed to the rearrangement of the polymer chain, which results in membrane swelling and/or change of membrane surface hydrophilicity.

  3. Conformationally Preorganized Diastereomeric Norbornane-Based Maltosides for Membrane Protein Study

    DEFF Research Database (Denmark)

    Das, Manabendra; Du, Yang; Ribeiro, Orquidea

    2017-01-01

    were generally better at stabilizing membrane proteins than short alkyl chain agents. Furthermore, use of one well-behaving NBM enabled us to attain a marked stabilization and clear visualization of a challenging membrane protein complex using electron microscopy. Thus, this study not only describes......Detergents are essential tools for functional and structural studies of membrane proteins. However, conventional detergents are limited in their scope and utility, particularly for eukaryotic membrane proteins. Thus, there are major efforts to develop new amphipathic agents with enhanced properties....... Here, a novel class of diastereomeric agents with a preorganized conformation, designated norbornane-based maltosides (NBMs), were prepared and evaluated for their ability to solubilize and stabilize membrane proteins. Representative NBMs displayed enhanced behaviors compared to n...

  4. Halloysite nanotube-based electrospun ceramic nanofibre mat: a novel support for zeolite membranes

    Science.gov (United States)

    Chen, Zhuwen; Zeng, Jiaying; Lv, Dong; Gao, Jinqiang; Zhang, Jian; Bai, Shan; Li, Ruili; Hong, Mei; Wu, Jingshen

    2016-12-01

    Some key parameters of supports such as porosity, pore shape and size are of great importance for fabrication and performance of zeolite membranes. In this study, we fabricated millimetre-thick, self-standing electrospun ceramic nanofibre mats and employed them as a novel support for zeolite membranes. The nanofibre mats were prepared by electrospinning a halloysite nanotubes/polyvinyl pyrrolidone composite followed by a programmed sintering process. The interwoven nanofibre mats possess up to 80% porosity, narrow pore size distribution, low pore tortuosity and highly interconnected pore structure. Compared with the commercial α-Al2O3 supports prepared by powder compaction and sintering, the halloysite nanotube-based mats (HNMs) show higher flux, better adsorption of zeolite seeds, adhesion of zeolite membranes and lower Al leaching. Four types of zeolite membranes supported on HNMs have been successfully synthesized with either in situ crystallization or a secondary growth method, demonstrating good universality of HNMs for supporting zeolite membranes.

  5. Studies of rubidium selenate with secondary phase of RbOH under humidified reducing atmosphere

    International Nuclear Information System (INIS)

    Beyribey, Berceste; Hallinder, Jonathan; Poulsen, Finn Willy; Bonanos, Nikolaos; Mogensen, Mogens

    2012-01-01

    Highlights: ► Degradation of Rb 2 SeO 3 and Rb 2 SeO 4 to form RbOH provide protonic conductivity. ► The conductivity increases by increasing temperature. ► The highest conductivity value of 2.01·10 −4 S cm −1 is observed at 317 °C. ► The work may state conductivity rise in solid acid electrolytes upon decomposition. - Abstract: The high temperature properties of Rb 2 SeO 4 have been studied by calorimetry, impedance spectroscopy and X-ray powder diffraction. As synthesized, Rb 2 SeO 4 includes a second phase of Rb 2 SeO 3 , which can be eliminated upon heating the compound. As expected, no conductivity is observed in dry (pH 2 O 2 O = 0.1 bar) air at 176 °C, the conductivity increases sharply from 8.6·10 −8 to 1.7·10 −6 S cm −1 . Under humidified (pH 2 O = 0.1 bar) reducing atmosphere (9%H 2 in N 2 ), the conductivity increases to 2.0·10 −4 S cm −1 at 317 °C. Degradation of Rb 2 SeO 3 and Rb 2 SeO 4 to form RbOH, which is known as a proton conductor, are thought to be responsible for the observed conductivity in humidified atmospheres. Our observations may explain the conductivity rise in other solid acid electrolytes, including sulfate and selenate groups, around their decomposition temperatures, in humidified atmospheres.

  6. Colorimetric test-systems for creatinine detection based on composite molecularly imprinted polymer membranes.

    Science.gov (United States)

    Sergeyeva, T A; Gorbach, L A; Piletska, E V; Piletsky, S A; Brovko, O O; Honcharova, L A; Lutsyk, O D; Sergeeva, L M; Zinchenko, O A; El'skaya, A V

    2013-04-03

    An easy-to-use colorimetric test-system for the efficient detection of creatinine in aqueous samples was developed. The test-system is based on composite molecularly imprinted polymer (MIP) membranes with artificial receptor sites capable of creatinine recognition. A thin MIP layer was created on the surface of microfiltration polyvinylidene fluoride (PVDF) membranes using method of photo-initiated grafting polymerization. The MIP layer was obtained by co-polymerization of a functional monomer (e.g. 2-acrylamido-2-methyl-1-propanesulfonic acid, itaconic acid or methacrylic acid) with N, N'-methylenebisacrylamide as a cross-linker. The choice of the functional monomer was based on the results of computational modeling. The creatinine-selective composite MIP membranes were used for measuring creatinine in aqueous samples. Creatinine molecules were selectively adsorbed by the MIP membranes and quantified using color reaction with picrates. The intensity of MIP membranes staining was proportional to creatinine concentration in an analyzed sample. The colorimetric test-system based on the composite MIP membranes was characterized with 0.25 mM detection limit and 0.25-2.5mM linear dynamic range. Storage stability of the MIP membranes was estimated as at least 1 year at room temperature. As compared to the traditional methods of creatinine detection the developed test-system is characterized by simplicity of operation, small size and low cost. Copyright © 2013 Elsevier B.V. All rights reserved.

  7. A micromachined membrane-based active probe for biomolecular mechanics measurement

    Science.gov (United States)

    Torun, H.; Sutanto, J.; Sarangapani, K. K.; Joseph, P.; Degertekin, F. L.; Zhu, C.

    2007-04-01

    A novel micromachined, membrane-based probe has been developed and fabricated as assays to enable parallel measurements. Each probe in the array can be individually actuated, and the membrane displacement can be measured with high resolution using an integrated diffraction-based optical interferometer. To illustrate its application in single-molecule mechanics experiments, this membrane probe was used to measure unbinding forces between L-selectin reconstituted in a polymer-cushioned lipid bilayer on the probe membrane and an antibody adsorbed on an atomic force microscope cantilever. Piconewton range forces between single pairs of interacting molecules were measured from the cantilever bending while using the membrane probe as an actuator. The integrated diffraction-based optical interferometer of the probe was demonstrated to have floor for frequencies as low as 3 Hz with a differential readout scheme. With soft probe membranes, this low noise level would be suitable for direct force measurements without the need for a cantilever. Furthermore, the probe membranes were shown to have 0.5 µm actuation range with a flat response up to 100 kHz, enabling measurements at fast speeds.

  8. A high stability Ni-La0.5Ce0.5O2-δ asymmetrical metal-ceramic membrane for hydrogen separation and generation

    Science.gov (United States)

    Zhu, Zhiwen; Sun, Wenping; Wang, Zhongtao; Cao, Jiafeng; Dong, Yingchao; Liu, Wei

    2015-05-01

    In this work, hydrogen permeation properties of Ni-La0.5Ce0.5O2-δ (LDC) asymmetrical cermet membrane are investigated, including hydrogen fluxes (JH2) under different hydrogen partial pressures, the influence of water vapor on JH2 and the long-term stability of the membrane operating under the containing-CO2 atmosphere. Ni-LDC asymmetrical membrane shows the best hydrogen permeability among LDC-based hydrogen separation membranes, inferior to Ni-BaZr0.1Ce0.7Y0.2O3-δ asymmetrical membrane. The water vapor in feed gas is beneficial to hydrogen transport process, which promote an increase of JH2 from 5.64 × 10-8 to 6.83 × 10-8 mol cm-2 s-1 at 900 °C. Stability testing of hydrogen permeation suggests that Ni-LDC membrane remains stable against CO2. A dual function of combining hydrogen separation and generation can be realized by humidifying the sweep gas and enhance the hydrogen output by 1.0-1.5 times. Ni-LDC membrane exhibits desirable performance and durability in dual-function mode. Morphologies and phase structures of the membrane after tests are also characterized by SEM and XRD.

  9. Ultra-modified rapid sequence induction with transnasal humidified rapid insufflation ventilatory exchange: Challenging convention

    Directory of Open Access Journals (Sweden)

    Ketan Sakharam Kulkarni

    2018-01-01

    Full Text Available During positive pressure ventilation, gastric inflation and subsequent pulmonary aspiration can occur. Rapid sequence induction (RSI technique is an age-old formula to prevent this. We adopted a novel approach of RSI for patients with high risk of aspiration and evaluated it further in patients undergoing laparoscopic surgeries. We believe that, in patients with risk of gastric insufflation and pulmonary aspiration, transnasal humidified rapid-insufflation ventilatory exchange can be useful in facilitating pre- and apnoeic oxygenation till tracheal isolation is achieved.

  10. Novel polyvinyl alcohol-bioglass 45S5 based composite nanofibrous membranes as bone scaffolds

    Energy Technology Data Exchange (ETDEWEB)

    Shankhwar, Nisha [Department of Physics, Indian Institute of Technology Guwahati, Guwahati 781039 (India); Kumar, Manishekhar; Mandal, Biman B. [Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039 (India); Srinivasan, A., E-mail: asrini@iitg.ernet.in [Department of Physics, Indian Institute of Technology Guwahati, Guwahati 781039 (India)

    2016-12-01

    Composite nanofibrous membranes based on sol-gel derived 45SiO{sub 2} 24.5CaO 24.5 Na{sub 2}O 6 P{sub 2}O{sub 5} (bioglass, BG) and 43SiO{sub 2} 24.5CaO 24.5 Na{sub 2}O 6 P{sub 2}O{sub 5} 2Fe{sub 2}O{sub 3} (magnetic bioglass, MBG) blended with polyvinyl alcohol (PVA) have been electrospun. These low cost membranes were mostly amorphous in structure with minor crystalline (sodium calcium phosphate) precipitates. All membranes were biodegradable. Among these, the composites exhibited higher tensile strength, better proliferation of human osteosarcoma MG63 cells and higher alkaline phosphatase enzyme activity than the bare PVA membrane, indicating their potential in bone tissue engineering. The magnetic PVA-MBG scaffold was also found to be a promising candidate for magnetic hyperthermia application. - Highlights: • Electrospun low-cost PVA-45S5 bioglass (BG) nanofibrous membranes • PVA-BG membranes containing 2 wt.% Fe{sub 2}O{sub 3} exhibit spontaneous magnetization. • BG fillers strongly enhanced mechanical strength and bioresponse of membranes. • Membranes show promise for bone scaffold and hyperthermia applications.

  11. Novel polyvinyl alcohol-bioglass 45S5 based composite nanofibrous membranes as bone scaffolds

    International Nuclear Information System (INIS)

    Shankhwar, Nisha; Kumar, Manishekhar; Mandal, Biman B.; Srinivasan, A.

    2016-01-01

    Composite nanofibrous membranes based on sol-gel derived 45SiO 2 24.5CaO 24.5 Na 2 O 6 P 2 O 5 (bioglass, BG) and 43SiO 2 24.5CaO 24.5 Na 2 O 6 P 2 O 5 2Fe 2 O 3 (magnetic bioglass, MBG) blended with polyvinyl alcohol (PVA) have been electrospun. These low cost membranes were mostly amorphous in structure with minor crystalline (sodium calcium phosphate) precipitates. All membranes were biodegradable. Among these, the composites exhibited higher tensile strength, better proliferation of human osteosarcoma MG63 cells and higher alkaline phosphatase enzyme activity than the bare PVA membrane, indicating their potential in bone tissue engineering. The magnetic PVA-MBG scaffold was also found to be a promising candidate for magnetic hyperthermia application. - Highlights: • Electrospun low-cost PVA-45S5 bioglass (BG) nanofibrous membranes • PVA-BG membranes containing 2 wt.% Fe 2 O 3 exhibit spontaneous magnetization. • BG fillers strongly enhanced mechanical strength and bioresponse of membranes. • Membranes show promise for bone scaffold and hyperthermia applications.

  12. 2D fluorescence spectroscopy for monitoring ion-exchange membrane based technologies - Reverse electrodialysis (RED).

    Science.gov (United States)

    Pawlowski, Sylwin; Galinha, Claudia F; Crespo, João G; Velizarov, Svetlozar

    2016-01-01

    Reverse electrodialysis (RED) is one of the emerging, membrane-based technologies for harvesting salinity gradient energy. In RED process, fouling is an undesirable operation constraint since it leads to a decrease of the obtainable net power density due to increasing stack electric resistance and pressure drop. Therefore, early fouling detection is one of the main challenges for successful RED technology implementation. In the present study, two-dimensional (2D) fluorescence spectroscopy was used, for the first time, as a tool for fouling monitoring in RED. Fluorescence excitation-emission matrices (EEMs) of ion-exchange membrane surfaces and of natural aqueous streams were acquired during one month of a RED stack operation. Fouling evolvement on the ion-exchange membrane surfaces was successfully followed by 2D fluorescence spectroscopy and quantified using principal components analysis (PCA). Additionally, the efficiency of cleaning strategy was assessed by measuring the membrane fluorescence emission intensity before and after cleaning. The anion-exchange membrane (AEM) surface in contact with river water showed to be significantly affected due to fouling by humic compounds, which were found to cross through the membrane from the lower salinity (river water) to higher salinity (sea water) stream. The results obtained show that the combined approach of using 2D fluorescence spectroscopy and PCA has a high potential for studying fouling development and membrane cleaning efficiency in ion exchange membrane processes. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. A photo-tunable membrane based on inter-particle crosslinking for decreasing diffusion rates

    KAUST Repository

    Li, Song

    2015-01-01

    Functional polymeric membranes are widely used to adjust and control the diffusion of molecules. Herein, photosensitive poly(hydroxycinnamic acid) (PHCA) microspheres, which were fabricated by an emulsification solvent-evaporation method, were embedded into an ethyl cellulose matrix to fabricate composite membranes with a photo-tunable property. The photoreaction of PHCA is based on the [2 + 2] cycloaddition of cinnamic moieties upon irradiation with 365 nm light. Intra-particle crosslinking in PHCA microspheres was confirmed in the solution phase, while inter-particle crosslinking between adjacent PHCA microspheres dominated the solid membrane phase. The inter-particle crosslinking turned down the permeability of the composite membranes by 74%. To prove the applicability of the designed system, the composite membrane was coated on a model drug reservoir tablet. Upon irradiating the tablet with UV light, the original permeability decreased by 57%, and consequently the diffusion rate of the cargo (Rhodamine B) from the tablet slowed down. Most importantly, the tablet showed sustained release for over 10 days. This controllability can be further tuned by adjusting the membrane thickness. Composite membranes showed excellent processing reproducibility together with consistent mechanical properties. These results demonstrate that the incorporation of photosensitive PHCA microspheres in polymeric membranes provides a promising photo-tunable material for different applications including coating and separation. This journal is © The Royal Society of Chemistry 2015.

  14. Preparation and characterization of novel antibacterial castor oil-based polyurethane membranes for wound dressing application.

    Science.gov (United States)

    Yari, Abbas; Yeganeh, Hamid; Bakhshi, Hadi; Gharibi, Reza

    2014-01-01

    Preparation of novel antibacterial and cytocompatible polyurethane membranes as occlusive dressing, which can provide moist and sterile environment over mild exudative wounds is considered in this work. In this regard, an epoxy-terminated polyurethane (EPU) prepolymer based on castor oil and glycidyltriethylammonium chloride (GTEAC) as a reactive bactericidal agent were synthesized. Polyurethane membranes were prepared through cocuring of EPU and different content of GTEAC with 1,4-butane diamine. The physical and mechanical properties, as well as cytocompatibility and antibacterial performance of prepared membranes were studied. Depending on their chemical formulations, the equilibrium water absorption and water vapor transmission rate values of the membranes were in ranges of 3-85% and 53-154g m(-2) day(-1), respectively. Therefore, these transparent membranes can maintain for a long period the moist environment over the wounds with low exudates. Detailed cytotoxicity analysis of samples against mouse L929 fibroblast and MCA-3D keratinocyte cells showed good level of cytocompatibility of membranes after purification via extraction of residual unreacted GTEAC moieties. The antibacterial activity of the membranes against Escherichia coli and Staphylococcus aureus bacteria was also studied. The membrane containing 50% GTEAC exhibited an effective antibacterial activity, while showed acceptable cytocompatibility and therefore, can be applied as an antibacterial occlusive wound dressing. Copyright © 2013 Wiley Periodicals, Inc., a Wiley Company.

  15. Vanadium Redox Flow Batteries Using meta-Polybenzimidazole-Based Membranes of Different Thicknesses.

    Science.gov (United States)

    Noh, Chanho; Jung, Mina; Henkensmeier, Dirk; Nam, Suk Woo; Kwon, Yongchai

    2017-10-25

    15, 25, and 35 μm thick meta-polybenzimidazole (PBI) membranes are doped with H 2 SO 4 and tested in a vanadium redox flow battery (VRFB). Their performances are compared with those of Nafion membranes. Immersed in 2 M H 2 SO 4 , PBI absorbs about 2 mol of H 2 SO 4 per mole of repeat unit. This results in low conductivity and low voltage efficiency (VE). In ex-situ tests, meta-PBI shows a negligible crossover of V 3+ and V 4+ ions, much lower than that of Nafion. This is due to electrostatic repulsive forces between vanadium cations and positively charged protonated PBI backbones, and the molecular sieving effect of PBI's nanosized pores. It turns out that charge efficiency (CE) of VRFBs using meta-PBI-based membranes is unaffected by or slightly increases with decreasing membrane thickness. Thick meta-PBI membranes require about 100 mV larger potentials to achieve the same charging current as thin meta-PBI membranes. This additional potential may increase side reactions or enable more vanadium ions to overcome the electrostatic energy barrier and to enter the membrane. On this basis, H 2 SO 4 -doped meta-PBI membranes should be thin to achieve high VE and CE. The energy efficiency of 15 μm thick PBI reaches 92%, exceeding that of Nafion 212 and 117 (N212 and N117) at 40 mA cm -2 .

  16. Membrane morphological study nanostructured based hydrophobic/hydrophilic applied in devices of PEMFC

    International Nuclear Information System (INIS)

    Loureiro, Felipe Augusto M.; Dahmouche, K; Rocco, Ana Maria

    2015-01-01

    The increasingly high energy demand generated by the increase of world population and consumption of fuels based on non-renewable sources has stimulated, in recent decades, the development of alternatives with less environmental impact and are based on renewable sources. Among these, the fuel cells (FC) have extremely promising possibilities. For the development of FC with market viability, it is necessary to obtain materials with optimized properties, among which the proton conducting membranes. In this work, we developed semi-interpenetrating polymer membranes (SIPN) based on diglycidyl ether of bisphenol-A (DGEBA) and polyethyleneimine (PEI), aiming their application in PEMFC. The membranes nanostructure was studied by AFM and SAXS means and it was identified ordinate hydrophobic/hydrophilic nano domains, which have determined the membrane properties, specially the proton conductivity. (author)

  17. Nafion-based nanocomposite membranes for fuel cells

    CSIR Research Space (South Africa)

    Cele, NP

    2008-11-01

    Full Text Available . Zhang, J. Wang and F. Sheu, Journal of Electroanalytical Chemistry, 577 (2005) 295 J. James, T.Z. McMaster, J.M. Newton, M.J. Miles, Polymer 41 (2000) 4223 M. Ludvigsson, J. Lindgren, J. Tegenfeldt, Electrochim. Acta (2000) 2267 Shoibal Banerjee..., Dennis E. Curtin Journal of Fluorine Chemistry 125 (2004) 1211–1216 1. 2. 3. 4. 5. CPO-0023 By incorporating multi walled carbon nanotubes onto proton exchange membranes (PEM), its thermal stability is increased, making PEM fuel cells ideal...

  18. Imidazolium-Based Polymeric Materials as Alkaline Anion-Exchange Fuel Cell Membranes

    Science.gov (United States)

    Narayan, Sri R.; Yen, Shiao-Ping S.; Reddy, Prakash V.; Nair, Nanditha

    2012-01-01

    Polymer electrolyte membranes that conduct hydroxide ions have potential use in fuel cells. A variety of polystyrene-based quaternary ammonium hydroxides have been reported as anion exchange fuel cell membranes. However, the hydrolytic stability and conductivity of the commercially available membranes are not adequate to meet the requirements of fuel cell applications. When compared with commercially available membranes, polystyrene-imidazolium alkaline membrane electrolytes are more stable and more highly conducting. At the time of this reporting, this has been the first such usage for imidazolium-based polymeric materials for fuel cells. Imidazolium salts are known to be electrochemically stable over wide potential ranges. By controlling the relative ratio of imidazolium groups in polystyrene-imidazolium salts, their physiochemical properties could be modulated. Alkaline anion exchange membranes based on polystyrene-imidazolium hydroxide materials have been developed. The first step was to synthesize the poly(styrene-co-(1-((4-vinyl)methyl)-3- methylimidazolium) chloride through a free-radical polymerization. Casting of this material followed by in situ treatment of the membranes with sodium hydroxide solutions provided the corresponding hydroxide salts. Various ratios of the monomers 4-chloromoethylvinylbenzine (CMVB) and vinylbenzine (VB) provided various compositions of the polymer. The preferred material, due to the relative ease of casting the film, and its relatively low hygroscopic nature, was a 2:1 ratio of CMVB to VB. Testing confirmed that at room temperature, the new membranes outperformed commercially available membranes by a large margin. With fuel cells now in use at NASA and in transportation, and with defense potential, any improvement to fuel cell efficiency is a significant development.

  19. Probing nanomechanical interaction at the interface between biological membrane and potentially toxic chemical.

    Science.gov (United States)

    Lim, Chanoong; Park, Sohee; Park, Jinwoo; Ko, Jina; Lee, Dong Woog; Hwang, Dong Soo

    2018-04-12

    Various xenobiotics interact with biological membranes, and precise evaluations of the molecular interactions between them are essential to foresee the toxicity and bioavailability of existing or newly synthesized molecules. In this study, surface forces apparatus (SFA) measurement and Langmuir trough based tensiometry are performed to reveal nanomechanical interaction mechanisms between potential toxicants and biological membranes for ex vivo toxicity evaluation. As a toxicant, polyhexamethylene guanidine (PHMG) was selected because PHMG containing humidifier disinfectant and Vodka caused lots of victims in both S. Korea and Russia, respectively, due to the lack of holistic toxicity evaluation of PHMG. Here, we measured strong attraction (Wad ∼4.2 mJ/m 2 ) between PHMG and head group of biological membranes while no detectable adhesion force between the head group and control molecules was measured. Moreover, significant changes in π-A isotherm of 1,2-Dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC) monolayers were measured upon PHMG adsorption. These results indicate PHMG strongly binds to hydrophilic group of lipid membranes and alters the structural and phase behavior of them. More importantly, complementary utilization of SFA and Langmuir trough techniques are found to be useful to predict the potential toxicity of a chemical by evaluating the molecular interaction with biological membranes, the primary protective barrier for living organisms. Copyright © 2018 Elsevier B.V. All rights reserved.

  20. Long-Time Plasma Membrane Imaging Based on a Two-Step Synergistic Cell Surface Modification Strategy.

    Science.gov (United States)

    Jia, Hao-Ran; Wang, Hong-Yin; Yu, Zhi-Wu; Chen, Zhan; Wu, Fu-Gen

    2016-03-16

    Long-time stable plasma membrane imaging is difficult due to the fast cellular internalization of fluorescent dyes and the quick detachment of the dyes from the membrane. In this study, we developed a two-step synergistic cell surface modification and labeling strategy to realize long-time plasma membrane imaging. Initially, a multisite plasma membrane anchoring reagent, glycol chitosan-10% PEG2000 cholesterol-10% biotin (abbreviated as "GC-Chol-Biotin"), was incubated with cells to modify the plasma membranes with biotin groups with the assistance of the membrane anchoring ability of cholesterol moieties. Fluorescein isothiocyanate (FITC)-conjugated avidin was then introduced to achieve the fluorescence-labeled plasma membranes based on the supramolecular recognition between biotin and avidin. This strategy achieved stable plasma membrane imaging for up to 8 h without substantial internalization of the dyes, and avoided the quick fluorescence loss caused by the detachment of dyes from plasma membranes. We have also demonstrated that the imaging performance of our staining strategy far surpassed that of current commercial plasma membrane imaging reagents such as DiD and CellMask. Furthermore, the photodynamic damage of plasma membranes caused by a photosensitizer, Chlorin e6 (Ce6), was tracked in real time for 5 h during continuous laser irradiation. Plasma membrane behaviors including cell shrinkage, membrane blebbing, and plasma membrane vesiculation could be dynamically recorded. Therefore, the imaging strategy developed in this work may provide a novel platform to investigate plasma membrane behaviors over a relatively long time period.

  1. Ion-Exchange Membranes Based on Polynorbornenes with Fluorinated Imide Side Chain Groups

    Directory of Open Access Journals (Sweden)

    Arlette A. Santiago

    2012-01-01

    Full Text Available The electrochemical characteristics of cation-exchange membranes based on polynorbornenes with fluorinated and sulfonated dicarboximide side chain groups were reported. This study was extended to a block copolymer containing structural units with phenyl and 4-oxybenzenesulfonic acid, 2,3,5,6-tetrafluorophenyl moieties replacing the hydrogen atom of the dicarboximide group. A thorough study on the electrochemical characteristics of the membranes involving electromotive forces of concentration cells and proton conductivity is reported. The proton permselectivity of the membranes is also discussed.

  2. PVDF-HFP-based porous polymer electrolyte membranes for lithium-ion batteries

    DEFF Research Database (Denmark)

    Miao, Ruiying; Liu, Bowen; Zhu, Zhongzheng

    2008-01-01

    As a potential electrolyte for lithium-ion batteries, a porous polymer electrolyte membrane based on poly(vinylidenefluoride-hexafluoropropylene) (PVDF-HFP) was prepared by a phase inversion method. The casting solution, effects of the solvent and non-solvent and addition of micron scale TiO2...... particles were investigated. The membranes were characterized by SEM, XRD, AC impedance, and charge/discharge tests. By using acetone as the solvent and water as the non-solvent, the prepared membranes showed good ability to absorb and retain the lithium ion containing electrolyte. Addition of micron TiO2...

  3. Structurally stable graphene oxide-based nanofiltration membranes with bioadhesive polydopamine coating

    Science.gov (United States)

    Wang, Chongbin; Li, Zhiyuan; Chen, Jianxin; Yin, Yongheng; Wu, Hong

    2018-01-01

    Graphene oxide (GO)-based membranes possess promising potential in liquid separation for its high flux. The state-of-art GO-based membranes need to be supported by a substrate to ensure that the ultra-thin GO layer can withstand transmembrane pressure in practical applications. The interfacial compatibility of this kind of composite membrane remains a great challenge due to the intrinsic difference in chemical/physical properties between the GO sheets and the substrate. In this paper, a structurally stable GO-based composite nanofiltration membrane was fabricated by coupling the mussel-inspired adhesive platform and filtration-assisted assembly of GO laminates. The water flux for the prepared GO-based nanofiltration membrane reached up to 85 L m-2 h-1 bar-1 with a high retention above 95% and 100% for Orange G and Congo Red, respectively. The membrane exhibited highly stable structure owing to the covalent and noncovalent interactions between GO separation layer and dopamine adhesive platform.

  4. Cell membrane-based nanoparticles: a new biomimetic platform for tumor diagnosis and treatment

    Directory of Open Access Journals (Sweden)

    Ruixiang Li

    2018-01-01

    Full Text Available Taking inspiration from nature, the biomimetic concept has been integrated into drug delivery systems in cancer therapy. Disguised with cell membranes, the nanoparticles can acquire various functions of natural cells. The cell membrane-coating technology has pushed the limits of common nano-systems (fast elimination in circulation to more effectively navigate within the body. Moreover, because of the various functional molecules on the surface, cell membrane-based nanoparticles (CMBNPs are capable of interacting with the complex biological microenvironment of the tumor. Various sources of cell membranes have been explored to camouflage CMBNPs and different tumor-targeting strategies have been developed to enhance the anti-tumor drug delivery therapy. In this review article we highlight the most recent advances in CMBNP-based cancer targeting systems and address the challenges and opportunities in this field.

  5. Separation of tritiated water using graphene oxide membrane

    Energy Technology Data Exchange (ETDEWEB)

    Sevigny, Gary J. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Motkuri, Radha K. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Gotthold, David W. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Fifield, Leonard S. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Frost, Anthony P. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Bratton, Wesley [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)

    2015-06-28

    In future nuclear fuel reprocessing plants and possibly for nuclear power plants, the cleanup of tritiated water will be needed for hundreds of thousands of gallons of water with low activities of tritium. This cleanup concept utilizes graphene oxide laminar membranes (GOx) for the separation of low-concentration (10-3-10 µCi/g) tritiated water to create water that can be released to the environment and a much smaller waste stream with higher tritium concentrations. Graphene oxide membranes consist of hierarchically stacked, overlapping molecular layers and represent a new class of materials. A permeation rate test was performed with a 2-µm-thick cast Asbury membrane using mixed gas permeability testing with zero air (highly purified atmosphere) and with air humidified with either H2O or D2O to a nominal 50% relative humidity. The membrane permeability for both H2O and D2O was high with N2 and O2 at the system measurement limit. The membrane water permeation rate was compared to a Nafion® membrane and the GOx permeation was approximately twice as high at room temperature. The H2O vapor permeation rate was 5.9 × 102 cc/m2/min (1.2 × 10-6 g/min-cm2), which is typical for graphene oxide membranes. To demonstrate the feasibility of such isotopic water separation through GOX laminar membranes, an experimental setup was constructed to use pressure-driven separation by heating the isotopic water mixture at one side of the membrane to create steam while cooling the other side. Several membranes were tested and were prepared using different starting materials and by different pretreatment methods. The average separation result was 0.8 for deuterium and 0.6 for tritium. Higher or lower temperatures may also improve separation efficiency but neither has been tested yet. A rough estimate of cost compared to current technology was also included as an indication of potential viability of the process. The relative process costs were based on the rough size of facility to

  6. Development of Polybenzimidazole-Based High-Temperature Membrane and Electrode Assemblies for Stationary and Automotive Applications

    Energy Technology Data Exchange (ETDEWEB)

    Vogel, John A.

    2008-09-03

    The program began on August 1, 2003 and ended on July 31, 2007. The goal of the project was to optimize a high-temperature polybenzimidazole (PBI) membrane to meet the performance, durability, and cost targets required for stationary fuel cell applications. These targets were identified in the Fuel Cell section (3.4) of DOE’s Hydrogen, Fuel Cells and Infrastructure Technologies Program Multi-Year Research, Development and Demonstration Plan. A membrane that operates at high temperatures is important to the fuel cell industry because it is insensitive to carbon monoxide (a poison to low-temperature fuel cells), and does not require complex water management strategies. Together, these two benefits greatly simplify the fuel cell system. As a result, the high-temperature fuel cell system realizes a cost benefit as the number of components is reduced by nearly 30%. There is also an inherent reliability benefit as components such as humidifiers and pumps for water management are unnecessary. Furthermore, combined heat and power (CHP) systems may be the best solution for a commercial, grid-connected, stationary product that must offer a cost benefit to the end user. For a low-temperature system, the quality of the heat supplied is insufficient to meet consumer needs and comfort requirements, so peak heaters or supplemental boilers are required. The higher operating temperature of PBI technology allows the fuel cell to meet the heat and comfort demand without the additional equipment. Plug Power, working with the Rensselaer Polytechnic Institute (RPI) Polymer Science Laboratory, made significant advances in optimizing the PBI membrane material for operation at temperatures greater than 160oC with a lifetime of 40,000 hours. Supporting hardware such as flow field plates and a novel sealing concept were explored to yield the lower-cost stack assembly and corresponding manufacturing process. Additional work was conducted on acid loss, flow field design and cathode electrode

  7. PEMFC performance of MEAS based on Nafion{sup R} and sPSEBS hybrid membranes

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez-Carretero, F.J.; Compan, V. [Univ, Politecnica de Valencia, Valencia (Spain). Dept. Termodinamica Aplicada; Suarez, K.; Solorza, O. [Inst. Politecnico Nacional, Centro de Investigacion y de Estudios Avanzados, Mexico City (Mexico). Dept. de Quimica; Riande, E. [Inst. de Ciencia y Tecnologia de Polimeros, Madrid (Spain)

    2010-07-15

    Important scientific, technical and economic problems must be solved before widespread commercialization of polymer electrolyte membrane fuel cells (PEMFC). The main issues facing the development of commercial low temperature fuel cells are the synthesis of efficient solid electrolytes separating the anode from the cathode as well as the development of cheaper catalysts for fuel oxidation. This study involved the preparation of hybrid membranes based on Nafion 117 and sulfonated Calprene H6120 containing partially sulfonated inorganic fillers such as silica, SBA-15 and sepiolite. The feasibility of using the membranes as polyelectrolytes for low temperature fuel cells was then evaluated. The water uptake of Nafion hybrid membranes is 1/3 to 1/4 of that in composite membranes based on sulfonated Calprene H6120. The proton conductivity of Nafion 117 hybrid membranes-electrode assemblies is nearly 1/5 of the pristine Nafion membrane assembly. Sulfonated Calprene H6120 hybrid membranes typically have better proton conductivity than the Nafion 117 composites. The performance of fuel cells containing different MEAs was examined by measuring their polarization curves in different operating conditions. The kinetic parameters governing the voltage dependence on current density were also estimated. It was concluded that the superior performance of the fuel cells with MEAs of NAF-SEP, sPSEBS-SIL and sPSEBS-SBA is not due to the membranes themselves, but to the kinetic processes that occur at the electrodes, which in this study were less efficient for fuel cells with the Nafion MEA. 34 refs., 3 tabs., 9 figs.

  8. Clinical review: Humidifiers during non-invasive ventilation - key topics and practical implications

    Science.gov (United States)

    2012-01-01

    Inadequate gas conditioning during non-invasive ventilation (NIV) can impair the anatomy and function of nasal mucosa. The resulting symptoms may have a negative effect on patients' adherence to ventilatory treatment, especially for chronic use. Several parameters, mostly technical aspects of NIV, contribute to inefficient gas conditioning. Factors affecting airway humidity during NIV include inspiratory flow, inspiratory oxygen fraction, leaks, type of ventilator, interface used to deliver NIV, temperature and pressure of inhaled gas, and type of humidifier. The correct application of a humidification system may avoid the effects of NIV-induced drying of the airway. This brief review analyses the consequences of airway dryness in patients receiving NIV and the technical tools necessary to guarantee adequate gas conditioning during ventilatory treatment. Open questions remain about the timing of gas conditioning for acute or chronic settings, the choice and type of humidification device, the interaction between the humidifier and the underlying disease, and the effects of individual humidification systems on delivered humidity. PMID:22316078

  9. Humidifier disinfectant-associated lung injury in adults: Prognostic factors in predicting short-term outcome

    International Nuclear Information System (INIS)

    Koo, Hyun Jung; Do, Kyung-Hyun; Chae, Eun Jin; Kim, Hwa Jung; Song, Joon Seon; Jang, Se Jin; Hong, Sang-Bum; Huh, Jin Won; Lee, En; Hong, Soo-Jong

    2017-01-01

    To identify clinical and radiologic findings that affect disease severity and short-term prognosis of humidifier disinfectant-associated lung injury in adults and to compare computed tomography (CT) findings between the patients with and without death or lung transplantation. Fifty-nine adults (mean age, 34 years; M/F = 12:47) were enrolled in this retrospective study. Medical records and prospective surveillance data were used to assess clinical and radiological factors associated with a poor clinical outcome. Multivariate generalized estimating equation models were used to analyse serial CT findings. Overall cumulative major events including lung transplantation and mortality were assessed using the Kaplan-Meier method. Almost half needed ICU admission (47.5 %) and 17 died (28.8 %). Young age, peripartum and low O_2 saturation were factors associated with ICU admission. On initial chest radiographs, consolidation (P < 0.001) and ground-glass opacity (P = 0.01) were significantly noted in patients who required ICU admission. CT findings including consolidation (odds ratio (OR), 1.02), pneumomediastinum (OR, 1.66) and pulmonary interstitial emphysema (OR, 1.61) were the risk factors for lung transplantation and mortality. Clinical and radiologic findings are related to the risks of lung transplantation and mortality of humidifier disinfectant-associated lung injury. Consolidation, pneumomediastinum and pulmonary interstitial emphysema were short-term prognostic CT findings. (orig.)

  10. Humidifier disinfectant-associated lung injury in adults: Prognostic factors in predicting short-term outcome

    Energy Technology Data Exchange (ETDEWEB)

    Koo, Hyun Jung; Do, Kyung-Hyun; Chae, Eun Jin [University of Ulsan College of Medicine, Department of Radiology and Research Institute of Radiology, Asan Medical Center, Songpa-gu, Seoul (Korea, Republic of); Kim, Hwa Jung [University of Ulsan College of Medicine, Cancer Center, Department of Clinical Epidemiology and Biostatistics, Asan Medical Center, Seoul (Korea, Republic of); Song, Joon Seon; Jang, Se Jin [University of Ulsan College of Medicine, Department of Pathology, Asan Medical Center, Seoul (Korea, Republic of); Hong, Sang-Bum; Huh, Jin Won [University of Ulsan College of Medicine, Department of Pulmonary and Critical Care Medicine, Asan Medical Center, Seoul (Korea, Republic of); Lee, En [Inje University Haundae Paik Hospital, Department of Pediatrics, Busan (Korea, Republic of); Hong, Soo-Jong [University of Ulsan College of Medicine, Department of Pediatrics, Childhood Asthma and Atopy Center, Environmental Health Center, Asan Medical Center, Seoul (Korea, Republic of)

    2017-01-15

    To identify clinical and radiologic findings that affect disease severity and short-term prognosis of humidifier disinfectant-associated lung injury in adults and to compare computed tomography (CT) findings between the patients with and without death or lung transplantation. Fifty-nine adults (mean age, 34 years; M/F = 12:47) were enrolled in this retrospective study. Medical records and prospective surveillance data were used to assess clinical and radiological factors associated with a poor clinical outcome. Multivariate generalized estimating equation models were used to analyse serial CT findings. Overall cumulative major events including lung transplantation and mortality were assessed using the Kaplan-Meier method. Almost half needed ICU admission (47.5 %) and 17 died (28.8 %). Young age, peripartum and low O{sub 2} saturation were factors associated with ICU admission. On initial chest radiographs, consolidation (P < 0.001) and ground-glass opacity (P = 0.01) were significantly noted in patients who required ICU admission. CT findings including consolidation (odds ratio (OR), 1.02), pneumomediastinum (OR, 1.66) and pulmonary interstitial emphysema (OR, 1.61) were the risk factors for lung transplantation and mortality. Clinical and radiologic findings are related to the risks of lung transplantation and mortality of humidifier disinfectant-associated lung injury. Consolidation, pneumomediastinum and pulmonary interstitial emphysema were short-term prognostic CT findings. (orig.)

  11. Characterization of an engineered cellulose based membrane by thiol dendrimer for heavy metals removal

    OpenAIRE

    Algarra, Manuel; Vázquez, María Isabel; Alonso, Beatriz S.; Casado, Carmen Mª.; Casado, Juan; Benavente, Juana

    2014-01-01

    Diaminobutane based poly(propyleneimine) dendrimer functionalized with sixteen thiol groups, DAB-3-(SH)16, was successfully embeded in a swollen cellulosic support in order to achieve an easily handle engineered membrane. The membrane was characterised by physicochemical, electrical and transport measurements, and the effect of the dendrimer was established by comparing these results with those obtained for the original cellulosic support. Results show that dendrimer inclusion improves the me...

  12. Anion exchange membrane based on alkali doped poly(2,5-benzimidazole) for alkaline membrane fuel cell

    CSIR Research Space (South Africa)

    Luo, H

    2010-03-01

    Full Text Available was prepared. The alkali doped poly(2,5-benzimidazole) membrane is a promising candidate as anion exchange membrane for fuel cell application. The alkali doped poly(2,5-benzimidazole) membrane reached an anion conductivity of 2.3×10-2 S cm-1 at room temperature...

  13. Lactate Biosensor Based on Cellulose Acetate Membrane Bound Lactate Oxidase

    Directory of Open Access Journals (Sweden)

    Suman

    2007-05-01

    Full Text Available Lactate biosensor was fabricated by immobilizing lactate oxidase in cellulose acetate membrane and by mounting over the sensing part of Pt electrode (working and connected to Ag/AgCl electrode (reference along with auxillary electrode through potentiostat. The enzyme electrode was anodically polarized at +400 mV to generate electrons from H2O2, which was formed from oxidation of serum lactate by immobilized lactate oxidase. The minimum detection limit of the electrode was 0.1mmoles/L and sensitivity of the sensor was 0.008 mA/mM/L lactate. Assay coefficients of variation were < 2% .A good correlation (r=0.99 was found between lactate values obtained by colorimetric method and lactate biosensor. The self-life of the biosensor was 18 days at 4ºC and enzyme electrode can be re-used 150 times without any significant loss in enzyme activity.

  14. Structural and Electrochemical Analysis of PMMA Based Gel Electrolyte Membranes

    Directory of Open Access Journals (Sweden)

    Chithra M. Mathew

    2015-01-01

    Full Text Available New gel polymer electrolytes containing poly(vinylidene chloride-co-acrylonitrile and poly(methyl methacrylate are prepared by solution casting method. With the addition of 60 wt.% of EC to PVdC-AN/PMMA blend, ionic conductivity value 0.398×10-6 S cm−1 has been achieved. XRD and FT-IR studies have been conducted to investigate the structure and complexation in the polymer gel electrolytes. The FT-IR spectra show that the functional groups C=O and C≡N play major role in ion conduction. Thermal stability of the prepared membranes is found to be about 180°C.

  15. Dimer-based model for heptaspanning membrane receptors.

    Science.gov (United States)

    Franco, Rafael; Casadó, Vicent; Mallol, Josefa; Ferré, Sergi; Fuxe, Kjell; Cortés, Antonio; Ciruela, Francisco; Lluis, Carmen; Canela, Enric I

    2005-07-01

    The existence of intramembrane receptor-receptor interactions for heptaspanning membrane receptors is now fully accepted, but a model considering dimers as the basic unit that binds to two ligand molecules is lacking. Here, we propose a two-state-dimer model in which the ligand-induced conformational changes from one component of the dimer are communicated to the other. Our model predicts cooperativity in binding, which is relevant because the other current models fail to address this phenomenon satisfactorily. Our two-state-dimer model also predicts the variety of responses elicited by full or partial agonists, neutral antagonists and inverse agonists. This model can aid our understanding of the operation of heptaspanning receptors and receptor channels, and, potentially, be important for improving the treatment of cardiovascular, neurological and neuropsychyatric diseases.

  16. Theoretical studies on membrane-based gas separation using computational fluid dynamics (CFD) of mass transfer

    International Nuclear Information System (INIS)

    Sohrabi, M.R.; Marjani, A.; Davallo, M.; Moradi, S.; Shirazian, S.

    2011-01-01

    A 2D mass transfer model was developed to study carbon dioxide removal by absorption in membrane contactors. The model predicts the steady state absorbent and carbon dioxide concentrations in the membrane by solving the conservation equations. The continuity equations for three sub domains of the membrane contactor involving the tube; membrane and shell were obtained and solved by finite element method (FEM). The model was based on 'non-wetted mode' in which the gas phase filled the membrane pores. Laminar parabolic velocity profile was used for the liquid flow in the tube side; whereas, the gas flow in the shell side was characterized by Happel's free surface model. Axial and radial diffusion transport inside the shell, through the membrane, and within the tube side of the contactor was considered in the mass transfer model. The predictions of percent CO/sub 2/ removal obtained by modeling were compared with the experimental values obtained from literature. They were the experimental results for CO/sub 2/ removal from CO/sub 2//N/sub 2/ gas mixture with amines aqueous solutions as the liquid solvent using polypropylene membrane contactor. The modeling predictions were in good agreement with the experimental values for different values of gas and liquid flow rates. (author)

  17. Impact of monoolein on aquaporin1-based supported lipid bilayer membranes

    International Nuclear Information System (INIS)

    Wang, Zhining; Wang, Xida; Ding, Wande; Wang, Miaoqi; Gao, Congjie; Qi, Xin

    2015-01-01

    Aquaporin (AQP) based biomimetic membranes have attracted considerable attention for their potential water purification applications. In this paper, AQP1 incorporated biomimetic membranes were prepared and characterized. The morphology and structure of the biomimetic membranes were characterized by in situ atomic force microscopy (AFM), infrared absorption spectroscopy, fluorescence microscopy, and contact angle measurements. The nanofiltration performance of the AQP1 incorporated membranes was investigated at 4 bar by using 2 g l −1 NaCl as feed solution. Lipid mobility plays an important role in the performance of the AQP1 incorporated supported lipid bilayer (SLB) membranes. We demonstrated that the lipid mobility is successfully tuned by the addition of monoolein (MO). Through in situ AFM and fluorescence recovery after photo-bleaching (FRAP) measurements, the membrane morphology and the molecular mobility were studied. The lipid mobility increased in the sequence DPPC < DPPC/MO (R MO = 5/5) < DOPC/MO (R MO = 5/5) < DOPC, which is consistent with the flux increment and salt rejection. This study may provide some useful insights for improving the water purification performance of biomimetic membranes. (paper)

  18. Recast Nafion{sup R}-based membranes for direct methanol fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Dimitrova, Penka; Friedrich, Kaspar A.; Stimming, Ulrich; Vogt, Brunhilde [Department of Physics, Technische Universitaet Muenchen, D-80333 Munich (Germany)

    2001-07-01

    Commercially available Nafion{sup R} membranes at present do not meet the requirements for direct methanol fuel cell (DMFC) applications, amongst others factors because of their high methanol permeability. With the aim of improving this undesirable characteristic, a modification procedure has been applied to recast Nafion-based membranes. Membranes, containing different additives, are assessed with regard to their conductivity and methanol permeation rate. The preparation of the samples involves the introduction of a small amount of a high boiling point solvent to the as-received Nafion solution and then shaping the membranes by a recasting procedure (drying at room temperature and heating up to 150{sup o}C). An enhancement of the conductivity of the thermally treated membranes in comparison to the commercial Nafion 117 is found. The thickness-normalised methanol permeation rate of the samples, containing inorganic additives (Aerosil and molybdophosphoric acid) decreases compared to the pure recast and as-received Nafion membranes. The observed results are discussed in terms of the membrane structure and preparation. (author)

  19. Improving the mechanical properties of collagen-based membranes using silk fibroin for corneal tissue engineering.

    Science.gov (United States)

    Long, Kai; Liu, Yang; Li, Weichang; Wang, Lin; Liu, Sa; Wang, Yingjun; Wang, Zhichong; Ren, Li

    2015-03-01

    Although collagen with outstanding biocompatibility has promising application in corneal tissue engineering, the mechanical properties of collagen-based scaffolds, especially suture retention strength, must be further improved to satisfy the requirements of clinical applications. This article describes a toughness reinforced collagen-based membrane using silk fibroin. The collagen-silk fibroin membranes based on collagen [silk fibroin (w/w) ratios of 100:5, 100:10, and 100:20] were prepared by using silk fibroin and cross-linking by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide. These membranes were analyzed by scanning electron microscopy and their optical property, and NaCl and tryptophan diffusivity had been tested. The water content was found to be dependent on the content of silk fibroin, and CS10 membrane (loading 10 wt % of silk fibroin) performed the optimal mechanical properties. Also the suture experiments have proved CS10 has high suture retention strength, which can be sutured in rabbit eyes integrally. Moreover, the composite membrane proved good biocompatibility for the proliferation of human corneal epithelial cells in vitro. Lamellar keratoplasty shows that CS10 membrane promoted complete epithelialization in 35 ± 5 days, and their transparency is restored quickly in the first month. Corneal rejection reaction, neovascularization, and keratoconus are not observed. The composite films show potential for use in the field of corneal tissue engineering. © 2014 Wiley Periodicals, Inc.

  20. Remediation of textile effluents by membrane based treatment techniques: a state of the art review.

    Science.gov (United States)

    Dasgupta, Jhilly; Sikder, Jaya; Chakraborty, Sudip; Curcio, Stefano; Drioli, Enrico

    2015-01-01

    The textile industries hold an important position in the global industrial arena because of their undeniable contributions to basic human needs satisfaction and to the world economy. These industries are however major consumers of water, dyes and other toxic chemicals. The effluents generated from each processing step comprise substantial quantities of unutilized resources. The effluents if discharged without prior treatment become potential sources of pollution due to their several deleterious effects on the environment. The treatment of heterogeneous textile effluents therefore demands the application of environmentally benign technology with appreciable quality water reclamation potential. These features can be observed in various innovative membrane based techniques. The present review paper thus elucidates the contributions of membrane technology towards textile effluent treatment and unexhausted raw materials recovery. The reuse possibilities of water recovered through membrane based techniques, such as ultrafiltration and nanofiltration in primary dye houses or auxiliary rinse vats have also been explored. Advantages and bottlenecks, such as membrane fouling associated with each of these techniques have also been highlighted. Additionally, several pragmatic models simulating transport mechanism across membranes have been documented. Finally, various accounts dealing with techno-economic evaluation of these membrane based textile wastewater treatment processes have been provided. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Performance of EVA-Based Membranes for SCL in Hard Rock

    Science.gov (United States)

    Holter, Karl Gunnar

    2016-04-01

    The bonded property of multi-layered sprayed concrete tunnel linings (SCL) waterproofed with sprayed membranes means that the constituent materials will be exposed to the groundwater without any draining or mechanically separating measures. Moisture properties of the sprayed concrete and membrane materials are therefore important in order to establish the system properties of such linings. Ethyl-vinyl-acetate based sprayed membranes exhibit high water absorption potential under direct exposure to water, but are found to be significantly less hygroscopic and exhibit lower sorptivity (water absorption rate) than sprayed concrete. This material behavior explains the relatively dry in situ condition of the membrane that was observed. Measured in situ moisture content levels of the membrane material in tunnel linings have been found to vary within the range of 30-40 % of the maximum water absorption potential, and show a decreasing trend over the first 4 years after construction has been completed. A model for the mechanical loading, moisture condition and thermal exposure of the membrane and the resulting realistic parameters to be tested is presented. Laboratory testing methods for the membrane materials are evaluated considering possible loads, moisture and freezing exposure. Material testing of membrane materials was conducted with preconditioning to realistic moisture contents and under different temperature conditions including relevant freezing temperatures for tunnel linings. The main effects of the in situ moisture condition of the tested membrane materials are favorable tensile strengths in the range of 1.1-1.5 MPa and low risk of freeze-thaw damage. The crack bridging capacity of the tested membranes is found to be sensitive to temperature. With membrane thicknesses in the range of 3-4 mm, crack bridging capacity up to 4-6 mm opening of the crack width at 23 °C and approximately 1 mm opening at -3 °C was measured for the tested membranes. No significant

  2. Reforming of Liquid Hydrocarbons in a Novel Hydrogen-Selective Membrane-Based Fuel Processor

    Energy Technology Data Exchange (ETDEWEB)

    Shamsuddin Ilias

    2006-03-10

    In this work, asymmetric dense Pd/porous stainless steel composite membranes were fabricated by depositing palladium on the outer surface of the tubular support. The electroless plating method combined with an osmotic pressure field was used to deposit the palladium film. Surface morphology and microstructure of the composite membranes were characterized by SEM and EDX. The SEM and EDX analyses revealed strong adhesion of the plated pure palladium film on the substrate and dense coalescence of the Pd film. Membranes were further characterized by conducting permeability experiments with pure hydrogen, nitrogen, and helium gases at temperatures from 325 to 450 C and transmembrane pressure differences from 5 to 45 psi. The permeation results showed that the fabricated membranes have both high hydrogen permeability and selectivity. For example, the hydrogen permeability for a composite membrane with a 20 {micro}m Pd film was 3.02 x 10{sup -5} moles/m{sup 2}.s.Pa{sup 0.765} at 450 C. Hydrogen/nitrogen selectivity for this composite membrane was 1000 at 450 C with a transmembrane pressure difference of 14.7 psi. Steam reforming of methane is one of the most important chemical processes in hydrogen and syngas production. To investigate the usefulness of palladium-based composite membranes in membrane-reactor configuration for simultaneous production and separation of hydrogen, steam reforming of methane by equilibrium shift was studied. The steam reforming of methane using a packed-bed inert membrane tubular reactor (PBIMTR) was simulated. A two-dimensional pseudo-homogeneous reactor model with parallel flow configuration was developed for steam reforming of methane. The shell volume was taken as the feed and sweep gas was fed to the inside of the membrane tube. Radial diffusion was taken into account for concentration gradient in the radial direction due to hydrogen permeation through the membrane. With appropriate reaction rate expressions, a set of partial differential

  3. The development of membrane based high purity oily water separators for use in Arctic waters

    Energy Technology Data Exchange (ETDEWEB)

    Peng, H.; Tremblay, A.Y. [Ottawa Univ., ON (Canada). Dept. of Chemical Engineering, Industrial Membrane Centre; Veinot, D.E. [Defence Research and Development Canada, Halifax, NS (Canada)

    2005-07-01

    With increased exploration and industrial activity in the Canadian Arctic, interest in the Northwest Passage as a shipping route has also increased. The oily wastewater produced by ships must be treated prior to discharge, particularly in the sensitive Arctic environment where biodegradation of organics is very slow due to cold climatic conditions and low sunlight. As such, safe techniques are needed for the treatment of oily wastewater released from ships. However, bilge water is difficult to treat because it contains seawater, particulates, used oils and detergents. Membrane based oily water separators (OWS) are considered to be a key technology for the treatment of bilge water onboard ships. The issues that must be taken into account in the ship-born use of membrane based OWS include the proper treatment of the oily brine before discharge; the substantial reduction in volume that is required; the complexity of the technology; labour associated with the operation of the system due to filter changes and cleaning; and, system automation to simplify its operation. In this study, a membrane-based process for treating bilge water was developed to meet stringent discharge regulations for discharge in Arctic waters. Currently, this discharge limit is set at 0 ppm. A pilot scale membrane cascade system was designed and evaluated. Multilumen ceramic membranes were used in the first stage and Sepa{sup R} test cells were used in the second stage. Optimal membrane pore size was determined. The study investigated the separation of oil and grease using different molecular weight cut-off (MWCO) membranes. The study revealed that through proper membrane design, it is possible to remove oil and grease from bilge water to a level permitting its discharge to Arctic waters. However, it was recommended that low level aromatic diesel fuels be used in ships operating in Arctic waters since the presence of soluble aromatics in diesel fuel increases the technical difficulty of reaching

  4. Fluorescent sensor systems based on nanostructured polymeric membranes for selective recognition of Aflatoxin B1.

    Science.gov (United States)

    Sergeyeva, Tetyana; Yarynka, Daria; Piletska, Elena; Lynnik, Rostyslav; Zaporozhets, Olga; Brovko, Oleksandr; Piletsky, Sergey; El'skaya, Anna

    2017-12-01

    Nanostructured polymeric membranes for selective recognition of aflatoxin B1 were synthesized in situ and used as highly sensitive recognition elements in the developed fluorescent sensor. Artificial binding sites capable of selective recognition of aflatoxin B1 were formed in the structure of the polymeric membranes using the method of molecular imprinting. A composition of molecularly imprinted polymer (MIP) membranes was optimized using the method of computational modeling. The MIP membranes were synthesized using the non-toxic close structural analogue of aflatoxin B1, ethyl-2-oxocyclopentanecarboxylate as a dummy template. The MIP membranes with the optimized composition demonstrated extremely high selectivity towards aflatoxin B1 (AFB1). Negligible binding of close structural analogues of AFB1 - aflatoxins B2 (AFB2), aflatoxin G2 (AFG2), and ochratoxin A (OTA) was demonstrated. Binding of AFB1 by the MIP membranes was investigated as a function of both type and concentration of the functional monomer in the initial monomer composition used for the membranes' synthesis, as well as sample composition. The conditions of the solid-phase extraction of the mycotoxin using the MIP membrane as a stationary phase (pH, ionic strength, buffer concentration, volume of the solution, ratio between water and organic solvent, filtration rate) were optimized. The fluorescent sensor system based on the optimized MIP membranes provided a possibility of AFB1 detection within the range 14-500ngmL -1 demonstrating detection limit (3Ϭ) of 14ngmL -1 . The developed technique was successfully applied for the analysis of model solutions and waste waters from bread-making plants. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Effects of the operational conditions on the membrane and electrode properties of a polymer electrolyte fuel cell

    Directory of Open Access Journals (Sweden)

    Passos Raimundo R.

    2002-01-01

    Full Text Available The effects of the operational conditions on the membrane and electrode properties on a polymer electrolyte fuel cell (PEFC were investigated as a function of the cell and the gas humidifiers temperatures, the thickness of the membrane, the impregnation with phosphotungstic acid (PWA, and the variation of the Nafion and Teflon contents in the gas diffusion electrodes. An increase of the membrane resistance was observed when the PEFC is operated at temperatures equal or higher than those of the gas humidifiers, and this is more apparent for thicker electrolyte films. In the presence of PWA, the physicochemical properties of the membrane do not appreciably change with temperature. However, in this case, a lower humidification temperature affects the electrode performance. Changes on the Nafion loading in the electrodes do not lead to any significant effect in the electrode and membrane properties. For high Teflon contents there is a small lowering of the membrane conductivity.

  6. Development of novel membranes for blood purification therapies based on copolymers of N-vinylpyrrolidone and n-butylmethacrylate

    NARCIS (Netherlands)

    Tijink, M.S.L.; Janssen, J.; Timmer, M.; Austen, J.; Aldenhoff, Y.; Kooman, J.; Koole, L.H.; Damoiseaux, J.; van Oerle, R.; Henskens, Y.; Stamatialis, Dimitrios

    2013-01-01

    Developments in membrane based blood purification therapies often come with longer treatment times and therefore longer blood–material contact, which requires long-term membrane biocompatibility. In this study, we develop for the first time membranes for blood purification using the material

  7. Cross-linked PAN-based thin-film composite membranes for non-aqueous nanofiltration

    KAUST Repository

    Pérez-Manríquez, Liliana

    2015-01-01

    A new approach on the development of cross-linked PAN based thin film composite (TFC) membranes for non-aqueous application is presented in this work. Polypropylene backed neat PAN membranes fabricated by phase inversion process were cross-linked with hydrazine to get excellent solvent stability toward dimethylformamide (DMF). By interfacial polymerization a selective polyamide active layer was coated over the cross-linked PAN using N,N′-diamino piperazine (DAP) and trimesoyl chloride (TMC) as monomers. Permeation and molecular weight cut off (MWCO) experiments using various dyes were done to evaluate the performance of the membranes. Membranes developed by such method show excellent solvent stability toward DMF with a permeance of 1.7 L/m2 h bar and a molecular weight cut-off of less than 600 Da.

  8. Structure and functionality of PVdF/PAN based, composite proton conducting membranes

    International Nuclear Information System (INIS)

    Martinelli, A.; Navarra, M.A.; Matic, A.; Panero, S.; Jacobsson, P.; Boerjesson, L.; Scrosati, B.

    2005-01-01

    We have investigated new poly-vinylidene fluoride/poly-acrylonitrile (PVdF/PAN) based proton conducting membranes by means of vibrational spectroscopy. We find that a complete phase inversion occurs during the preparation procedure, when the gelling solvents are replaced by an acidic solution, providing the proton conducting property. The uptake of acid is promoted both by the presence of PAN and the ceramic filler, Al 2 O 3 . No particular interaction between the polymer matrix and the acidic solution could be detected, supporting the picture of an inert matrix entrapping a liquid component. However, the dissociation degree of the acid is decreased due to the spatial confinement in the membrane. By comparing the dissociation degree and the actual amount of acid in the membrane to the conductivity, we conclude that the limiting factor for the conductivity is the long-range mobility of the protons, which is governed by the morphology of the membrane

  9. Extraction or adsorption? Voltammetric assessment of protamine transfer at ionophore-based polymeric membranes.

    Science.gov (United States)

    Garada, Mohammed B; Kabagambe, Benjamin; Amemiya, Shigeru

    2015-01-01

    Cation-exchange extraction of polypeptide protamine from water into an ionophore-based polymeric membrane has been hypothesized as the origin of a potentiometric sensor response to this important heparin antidote. Here, we apply ion-transfer voltammetry not only to confirm protamine extraction into ionophore-doped polymeric membranes but also to reveal protamine adsorption at the membrane/water interface. Protamine adsorption is thermodynamically more favorable than protamine extraction as shown by cyclic voltammetry at plasticized poly(vinyl chloride) membranes containing dinonylnaphthalenesulfonate as a protamine-selective ionophore. Reversible adsorption of protamine at low concentrations down to 0.038 μg/mL is demonstrated by stripping voltammetry. Adsorptive preconcentration of protamine at the membrane/water interface is quantitatively modeled by using the Frumkin adsorption isotherm. We apply this model to ensure that stripping voltammograms are based on desorption of all protamine molecules that are transferred across the interface during a preconcentration step. In comparison to adsorption, voltammetric extraction of protamine requires ∼0.2 V more negative potentials, where a potentiometric super-Nernstian response to protamine is also observed. This agreement confirms that the potentiometric protamine response is based on protamine extraction. The voltammetrically reversible protamine extraction results in an apparently irreversible potentiometric response to protamine because back-extraction of protamine from the membrane extremely slows down at the mixed potential based on cation-exchange extraction of protamine. Significantly, this study demonstrates the advantages of ion-transfer voltammetry over potentiometry to quantitatively and mechanistically assess protamine transfer at ionophore-based polymeric membranes as foundation for reversible, selective, and sensitive detection of protamine.

  10. Hydration induced material transfer in membranes of osmotic pump tablets measured by synchrotron radiation based FTIR.

    Science.gov (United States)

    Wu, Li; Yin, Xianzhen; Guo, Zhen; Tong, Yajun; Feng, Jing; York, Peter; Xiao, Tiqiao; Chen, Min; Gu, Jingkai; Zhang, Jiwen

    2016-03-10

    Osmotic pump tablets are reliable oral controlled drug delivery systems based on their semipermeable membrane coating. This research used synchrotron radiation-based Fourier transform infrared (SR-FTIR) microspectroscopy and imaging to investigate the hydration induced material transfer in the membranes of osmotic pump tablets. SR-FTIR was applied to record and map the chemical information of a micro-region of the membranes, composed of cellulose acetate (CA, as the water insoluble matrix) and polyethylene glycol (PEG, as the soluble pore forming agent and plasticizing agent). The microstructure and chemical change of membranes hydrated for 0, 5, 10 and 30min were measured using SR-FTIR, combined with scanning electronic microscopy and atom force microscopy. The SR-FTIR microspectroscopy results indicated that there was a major change at the absorption range of 2700-3100cm(-1) in the membranes after different periods of hydration time. The absorption bands at 2870-2880cm(-1) and 2950-2960cm(-1) were assigned to represent CA and PEG, respectively. The chemical group signal distribution illustrated by the ratio of PEG to CA demonstrated that the trigger of drug release in the preliminary stage was due to the rapid transfer of PEG into liquid medium with a sharp decrease of PEG in the membranes. The SR-FTIR mapping results have demonstrated the hydration induced material transfer in the membranes of osmotic pump tablets and enabled reassessment of the drug release mechanism of membrane controlled osmotic pump systems. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Microalgae dewatering based on forward osmosis employing proton exchange membrane.

    Science.gov (United States)

    Son, Jieun; Sung, Mina; Ryu, Hoyoung; Oh, You-Kwan; Han, Jong-In

    2017-11-01

    In this study, electrically-facilitated forward osmosis (FO) employing proton exchange membrane (PEM) was established for the purpose of microalgae dewatering. An increase in water flux was observed when an external voltage was applied to the FO equipped with the PEM; as expected, the trend became more dramatic with both concentration of draw solution and applied voltage raised. With this FO used for microalgae dewatering, 247% of increase in flux and 86% in final biomass concentration were observed. In addition to the effect on flux improvement, the electrically-facilitated FO exhibited the ability to remove chlorophyll from the dewatered biomass, down to 0.021±0015mg/g cell. All these suggest that the newly suggested electrically-facilitated FO, one particularly employed PEM, can indeed offer a workable way of dewatering of microalgae; it appeared to be so because it can also remove the ever-problematic chlorophyll from extracted lipids in a simultaneous fashion. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Protective clothing based on permselective membrane carbon adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Gottschlich, D.; Baker, R. [Membrane Technology and Research, Inc., Menlo Park, CA (United States)

    1995-10-01

    The objective of the program is to develop improved protective clothing for use by workers engaged in decommissioning and decontamination of former Department of Energy sites, including those used for atomic weapons research and production. Such sites are contaminated with a variety of hazardous compounds, ranging from asbestos, mercury and other heavy metals, to toxic organic compounds, such as PCB and chlorinated solvents, and radioactive metals and salts. Because of the hazards of exposure to these materials, workers must wear protective garments. These garments, which are made from Saran{reg_sign}, butyl rubber or other impermeable materials, provide excellent protection against particulates, liquids, aerosols, organic vapors and gases, but are impermeable to water vapor. Consequently, humidity and temperature within the suit rise rapidly during use, causing increasing discomfort. Heat stress occurs if the suit is worn for more than brief periods without resting. The proposed technology concerns a new protective clothing fabric that combines a permselective membrane layer with a sorptive layer. If successfully developed, suits made from this fabric will offer equivalent, or better, protection than current materials, combined with a very high water vapor transmission rate (1,000 g/m{sup 2}{sm_bullet} day or more) that will dramatically improve {open_quotes}breathability,{close_quotes} comfort, and worker productivity.

  13. Protective clothing based on permselective membrane carbon adsorption

    International Nuclear Information System (INIS)

    Gottschlich, D.; Baker, R.

    1995-01-01

    The objective of the program is to develop improved protective clothing for use by workers engaged in decommissioning and decontamination of former Department of Energy sites, including those used for atomic weapons research and production. Such sites are contaminated with a variety of hazardous compounds, ranging from asbestos, mercury and other heavy metals, to toxic organic compounds, such as PCB and chlorinated solvents, and radioactive metals and salts. Because of the hazards of exposure to these materials, workers must wear protective garments. These garments, which are made from Saran reg-sign, butyl rubber or other impermeable materials, provide excellent protection against particulates, liquids, aerosols, organic vapors and gases, but are impermeable to water vapor. Consequently, humidity and temperature within the suit rise rapidly during use, causing increasing discomfort. Heat stress occurs if the suit is worn for more than brief periods without resting. The proposed technology concerns a new protective clothing fabric that combines a permselective membrane layer with a sorptive layer. If successfully developed, suits made from this fabric will offer equivalent, or better, protection than current materials, combined with a very high water vapor transmission rate (1,000 g/m 2 sm-bullet day or more) that will dramatically improve open-quotes breathability,close quotes comfort, and worker productivity

  14. Solid polymer electrolyte water electrolyser based on Nafion-TiO{sub 2} composite membrane for high temperature operation

    Energy Technology Data Exchange (ETDEWEB)

    Baglio, V.; Antonucci, V.; Arico, A.S. [CNR-ITAE, Messina (Italy); Matteucci, F.; Martina, F.; Zama, I. [Tozzi Renewable Energy SpA, Mezzano (Italy); Ciccarella, G. [National Nanotechnology Laboratory (NNL) of INFM-CNR, Distretto Tecnologico ISUFI, Innovazione, Universita del Salento, Lecce (Italy); Arriaga, L.G. [Centro de Investigacion y Desarrollo Tecnologico en Electroquimica, Queretaro Sanfandila (Mexico); Ornelas, R.

    2009-06-15

    A composite Nafion-TiO{sub 2} membrane was manufactured by a recast procedure, using an in-house prepared TiO{sub 2}. This membrane has shown promising properties for high temperature operation in an SPE electrolyser allowing to achieve higher performance with respect to a commercial Nafion 115 membrane. This effect is mainly due to the water retention properties of the TiO{sub 2} filler. A promising increase in electrical efficiency was recorded at low current densities for the composite membrane-based SPE electrolyser at high temperature compared to conventional membrane-based devices. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  15. Freestanding eggshell membrane-based electrodes for high-performance supercapacitors and oxygen evolution reaction

    Science.gov (United States)

    Geng, Jing; Wu, Hao; Al-Enizi, Abdullah M.; Elzatahry, Ahmed A.; Zheng, Gengfeng

    2015-08-01

    A type of freestanding, light-weight eggshell membrane-based electrode is demonstrated for supercapacitors and for oxygen evolution reaction (OER) catalysis. As a widely available daily waste, eggshell membranes have unique porous three-dimensional grid-like fibrous structures with relatively high surface area and abundant macropores, allowing for effective conjugation of carbon nanotubes and growth of NiCo2O4 nanowire arrays, an effective supercapacitor material and OER catalyst. The three-dimensional fibrous eggshell membrane frameworks with carbon nanotubes offer efficient pathways for charge transport, and the macropores between adjacent fibers are fully accessible for electrolytes and bubble evolution. As a supercapacitor, the eggshell membrane/carbon nanotube/NiCo2O4 electrode shows high specific capacitances at current densities from 1 to 20 A g-1, with excellent capacitance retention (>90%) at 10 A g-1 for over 10 000 cycles. When employed as an OER catalyst, this eggshell membrane-based electrode exhibits an OER onset potential of 1.53 V vs. the reversible hydrogen electrode (RHE), and a stable catalytic current density of 20 mA cm-2 at 1.65 V vs. the RHE.A type of freestanding, light-weight eggshell membrane-based electrode is demonstrated for supercapacitors and for oxygen evolution reaction (OER) catalysis. As a widely available daily waste, eggshell membranes have unique porous three-dimensional grid-like fibrous structures with relatively high surface area and abundant macropores, allowing for effective conjugation of carbon nanotubes and growth of NiCo2O4 nanowire arrays, an effective supercapacitor material and OER catalyst. The three-dimensional fibrous eggshell membrane frameworks with carbon nanotubes offer efficient pathways for charge transport, and the macropores between adjacent fibers are fully accessible for electrolytes and bubble evolution. As a supercapacitor, the eggshell membrane/carbon nanotube/NiCo2O4 electrode shows high specific

  16. Comparative ex vivo study on humidifying function of three speaking valves with integrated heat and moisture exchanger for tracheotomised patients

    NARCIS (Netherlands)

    van den Boer, C.; Lansaat, L.; Muller, S.H.; van den Brekel, M.W.M.; Hilgers, F.J.M.

    2015-01-01

    Objective Assessment of humidifying function of tracheotomy speaking valves with integrated heat and moisture exchanger. Design Ex vivo measurement of water exchange and storage capacity of three tracheotomy speaking valves: Humidiphon Plus, Spiro and ProTrach DualCare (with two different heat and

  17. Comparative ex vivo study on humidifying function of three speaking valves with integrated heat and moisture exchanger for tracheotomised patients

    NARCIS (Netherlands)

    van den Boer, C.; Lansaat, L.; Muller, S. H.; van den Brekel, M. W. M.; Hilgers, F. J. M.

    2015-01-01

    Assessment of humidifying function of tracheotomy speaking valves with integrated heat and moisture exchanger. Ex vivo measurement of water exchange and storage capacity of three tracheotomy speaking valves: Humidiphon Plus, Spiro and ProTrach DualCare (with two different heat and moisture

  18. Origins and Evolution of Inorganic-Based and MOF-Based Mixed-Matrix Membranes for Gas Separations

    Directory of Open Access Journals (Sweden)

    Edson V. Perez

    2016-09-01

    Full Text Available Gas separation for industrial, energy, and environmental applications requires low energy consumption and small footprint technology to minimize operating and capital costs for the processing of large volumes of gases. Among the separation methods currently being used, like distillation, amine scrubbing, and pressure and temperature swing adsorption, membrane-based gas separation has the potential to meet these demands. The key component, the membrane, must then be engineered to allow for high gas flux, high selectivity, and chemical and mechanical stability at the operating conditions of feed composition, pressure, and temperature. Among the new type of membranes studied that show promising results are the inorganic-based and the metal-organic framework-based mixed-matrix membranes (MOF-MMMs. A MOF is a unique material that offers the possibility of tuning the porosity of a membrane by introducing diffusional channels and forming a compatible interface with the polymer. This review details the origins of these membranes and their evolution since the first inorganic/polymer and MOF/polymer MMMs were reported in the open literature. The most significant advancements made in terms of materials, properties, and testing conditions are described in a chronological fashion.

  19. Model-based fault detection for proton exchange membrane fuel cell ...

    African Journals Online (AJOL)

    In this paper, an intelligent model-based fault detection (FD) is developed for proton exchange membrane fuel cell (PEMFC) dynamic systems using an independent radial basis function (RBF) networks. The novelty is that this RBF networks is used to model the PEMFC dynamic systems and residuals are generated based ...

  20. Recent developments in membrane-based separations in biotechnology processes: review.

    Science.gov (United States)

    Rathore, A S; Shirke, A

    2011-01-01

    Membrane-based separations are the most ubiquitous unit operations in biotech processes. There are several key reasons for this. First, they can be used with a large variety of applications including clarification, concentration, buffer exchange, purification, and sterilization. Second, they are available in a variety of formats, such as depth filtration, ultrafiltration, diafiltration, nanofiltration, reverse osmosis, and microfiltration. Third, they are simple to operate and are generally robust toward normal variations in feed material and operating parameters. Fourth, membrane-based separations typically require lower capital cost when compared to other processing options. As a result of these advantages, a typical biotech process has anywhere from 10 to 20 membrane-based separation steps. In this article we review the major developments that have occurred on this topic with a focus on developments in the last 5 years.

  1. Performance and economics of a Pd-based planar WGS membrane reactor for coal gasification

    Energy Technology Data Exchange (ETDEWEB)

    Dolan, M.D. [CSIRO Energy Technology, Pullenvale QLD 4069 (Australia); Donelson, R. [CSIRO Process Science and Engineering, Clayton VIC 3168 (Australia); Dave, N.C. [CSIRO Energy Technology, North Ryde NSW 2113 (Australia)

    2010-10-15

    Conceptual 300 tonne per day (tpd) H{sub 2}-from-coal plants have been the subject of several major costing exercises in the past decade. Incorporating conventional high- and low-temperature water-gas-shift (WGS) reactors, amine-based CO{sub 2} removal and PSA-based H{sub 2} purification systems, these studies provide a benchmark against which alternative H{sub 2}-from-coal technologies can be compared. The catalytic membrane reactor (CMR), combining a WGS catalyst and hydrogen-selective metal membrane, can potentially replace the multiple shift and separation stages of a plant based on conventional technology. CMR-based shift and separation offers several major advantages over the conventional approach, including greater-than-equilibrium WGS conversion, the containment of the CO{sub 2} at high-pressure and a reduction in the number of unit processes. To determine capital costs of a WGS CMR-based H{sub 2}-from-coal plant, a prototype planar CMR was constructed and tested with varying catalyst bed depth, residence time and membrane type (commercially-sourced 50 {mu}m Pd or 40 {mu}m Pd-25Ag wt%). Experiments to measure CO conversion, and H{sub 2} flux and yield were conducted at 400 C with a feed pressure of 20 bar H{sub 2}O:C ratio of 3 and a H{sub 2} product pressure of 1 bar. Under the optimum conditions examined (with a 40 {mu}m-thick Pd-25Ag membrane and <3 mm-thick catalyst bed), a membrane surface area of {proportional_to}25,000 m{sup 2} would be required to provide a throughput of 300 tpd with 85% H{sub 2} yield. The capital cost of the CMR component of the plant would be around $US 180 million (based on current metal prices), of which 73% can be attributed to the cost of the Pd-Ag alloy membranes. Incorporation of a membrane that meets the 2015 US DOE cost and flux targets would offer

  2. TiO2-Based Phosphoproteomic Analysis of the Plasma Membrane and the Effects of Phosphatase Inhibitor Treatment

    DEFF Research Database (Denmark)

    Thingholm, Tine; Larsen, Martin Røssel; Ingrell, Christian

    2008-01-01

    Phosphorylation of plasma membrane proteins frequently initiates signal transduction pathways or attenuate plasma membrane transport processes. Because of the low abundance and hydrophobic features of many plasma membrane proteins and the low stoichiometry of protein phosphorylation, studies...... of the plasma membrane phosphoproteome are challenging. We present an optimized analytical strategy for plasma membrane phosphoproteomics that combines efficient plasma membrane protein preparation with TiO 2-based phosphopeptide enrichment and high-performance mass spectrometry for phosphopeptide sequencing....... We used sucrose centrifugation in combination with sodium carbonate extraction to achieve efficient and reproducible purification of low microgram levels of plasma membrane proteins from human mesenchymal stem cells (hMSCs, 10 (7) cells), achieving more than 70% yield of membrane proteins...

  3. Polybenzimidazole-based mixed membranes with exceptional high water vapor permeability and selectivity

    KAUST Repository

    Akhtar, Faheem Hassan

    2017-09-13

    Polybenzimidazole (PBI), a thermal and chemically stable polymer, is commonly used to fabricate membranes for applications like hydrogen recovery at temperatures of more than 300 °C, fuel cells working in a highly acidic environment, and nanofiltration in aggressive solvents. This report shows for the first time use of PBI dense membranes for water vapor/gas separation applications. They showed an excellent selectivity and high water vapor permeability. Incorporation of inorganic hydrophilic titanium-based nano-fillers into the PBI matrix further increased the water vapor permeability and water vapor/N2 selectivity. The most selective mixed matrix membrane with 0.5 wt% loading of TiO2 nanotubes yielded a water vapor permeability of 6.8×104 Barrer and a H2O/N2 selectivity of 3.9×106. The most permeable membrane with 1 wt% loading of carboxylated TiO2 nanoparticles had a 7.1×104 Barrer water vapor permeability and a H2O/N2 selectivity of 3.1×106. The performance of these membranes in terms of water vapor transport and selectivity is among the highest reported ones. The remarkable ability of PBI to efficiently permeate water versus other gases opens the possibility to fabricate membranes for dehumidification of streams in harsh environments. This includes the removal of water from high temperature reaction mixtures to shift the equilibrium towards products.

  4. Development of a Multi-Channel Piezoelectric Acoustic Sensor Based on an Artificial Basilar Membrane

    Directory of Open Access Journals (Sweden)

    Youngdo Jung

    2013-12-01

    Full Text Available In this research, we have developed a multi-channel piezoelectric acoustic sensor (McPAS that mimics the function of the natural basilar membrane capable of separating incoming acoustic signals mechanically by their frequency and generating corresponding electrical signals. The McPAS operates without an external energy source and signal processing unit with a vibrating piezoelectric thin film membrane. The shape of the vibrating membrane was chosen to be trapezoidal such that different locations of membrane have different local resonance frequencies. The length of the membrane is 28 mm and the width of the membrane varies from 1 mm to 8 mm. Multiphysics finite element analysis (FEA was carried out to predict and design the mechanical behaviors and piezoelectric response of the McPAS model. The designed McPAS was fabricated with a MEMS fabrication process based on the simulated results. The fabricated device was tested with a mouth simulator to measure its mechanical and piezoelectrical frequency response with a laser Doppler vibrometer and acoustic signal analyzer. The experimental results show that the as fabricated McPAS can successfully separate incoming acoustic signals within the 2.5 kHz–13.5 kHz range and the maximum electrical signal output upon acoustic signal input of 94 dBSPL was 6.33 mVpp. The performance of the fabricated McPAS coincided well with the designed parameters.

  5. Polybenzimidazole-based mixed membranes with exceptional high water vapor permeability and selectivity

    KAUST Repository

    Akhtar, Faheem Hassan; Kumar, Mahendra; Villalobos, Luis Francisco; Shevate, Rahul; Vovusha, Hakkim; Schwingenschlö gl, Udo; Peinemann, Klaus-Viktor

    2017-01-01

    Polybenzimidazole (PBI), a thermal and chemically stable polymer, is commonly used to fabricate membranes for applications like hydrogen recovery at temperatures of more than 300 °C, fuel cells working in a highly acidic environment, and nanofiltration in aggressive solvents. This report shows for the first time use of PBI dense membranes for water vapor/gas separation applications. They showed an excellent selectivity and high water vapor permeability. Incorporation of inorganic hydrophilic titanium-based nano-fillers into the PBI matrix further increased the water vapor permeability and water vapor/N2 selectivity. The most selective mixed matrix membrane with 0.5 wt% loading of TiO2 nanotubes yielded a water vapor permeability of 6.8×104 Barrer and a H2O/N2 selectivity of 3.9×106. The most permeable membrane with 1 wt% loading of carboxylated TiO2 nanoparticles had a 7.1×104 Barrer water vapor permeability and a H2O/N2 selectivity of 3.1×106. The performance of these membranes in terms of water vapor transport and selectivity is among the highest reported ones. The remarkable ability of PBI to efficiently permeate water versus other gases opens the possibility to fabricate membranes for dehumidification of streams in harsh environments. This includes the removal of water from high temperature reaction mixtures to shift the equilibrium towards products.

  6. Correcting the wavefront aberration of membrane mirror based on liquid crystal spatial light modulator

    Science.gov (United States)

    Yang, Bin; Wei, Yin; Chen, Xinhua; Tang, Minxue

    2014-11-01

    Membrane mirror with flexible polymer film substrate is a new-concept ultra lightweight mirror for space applications. Compared with traditional mirrors, membrane mirror has the advantages of lightweight, folding and deployable, low cost and etc. Due to the surface shape of flexible membrane mirror is easy to deviate from the design surface shape, it will bring wavefront aberration to the optical system. In order to solve this problem, a method of membrane mirror wavefront aberration correction based on the liquid crystal spatial light modulator (LCSLM) will be studied in this paper. The wavefront aberration correction principle of LCSLM is described and the phase modulation property of a LCSLM is measured and analyzed firstly. Then the membrane mirror wavefront aberration correction system is designed and established according to the optical properties of a membrane mirror. The LCSLM and a Hartmann-Shack sensor are used as a wavefront corrector and a wavefront detector, respectively. The detected wavefront aberration is calculated and converted into voltage value on LCSLM for the mirror wavefront aberration correction by programming in Matlab. When in experiment, the wavefront aberration of a glass plane mirror with a diameter of 70 mm is measured and corrected for verifying the feasibility of the experiment system and the correctness of the program. The PV value and RMS value of distorted wavefront are reduced and near diffraction limited optical performance is achieved. On this basis, the wavefront aberration of the aperture center Φ25 mm in a membrane mirror with a diameter of 200 mm is corrected and the errors are analyzed. It provides a means of correcting the wavefront aberration of membrane mirror.

  7. Cross flow microfiltration of oil-water emulsions using clay based ceramic membrane support and TiO2 composite membrane

    OpenAIRE

    Kanchapogu Suresh; G. Pugazhenthi

    2017-01-01

    The main objective of this work is to study the effect of cross flow filtration conditions on the separation of oily wastewater using ceramic support and TiO2 membrane. Firstly, the low cost clay based ceramic membrane support was prepared by uniaxial compaction method using combination of pyrophyllite, quartz, feldspar, kaolin, ball clay and calcium carbonate along with PVA as a binder. Subsequently, TiO2 composite membrane was fabricated via hydrothermal route employing TiO2 sol derived fro...

  8. Facile Fabrication of a Gold Nanocluster-Based Membrane for the Detection of Hydrogen Peroxide

    Directory of Open Access Journals (Sweden)

    Pu Zhang

    2016-07-01

    Full Text Available In this work, we present a simple and rapid method to synthesize red luminescent gold nanoclusters (AuNCs with high quantum yield (QY, ~16%, excellent photostability and biocompatibility. Next, we fabricated a solid membrane by loading the as-prepared AuNCs in an agar matrix. Different from nanomaterials dispersed in solution, the AuNCs-based solid membrane has distinct advantages including convenience of transportation, while still maintaining strong red luminescence, and relatively long duration storage without aggregation. Taking hydrogen peroxide (H2O2 as a typical example, we then employed the AuNCs as a luminescent probe and investigated their sensing performance, either in solution phase or on a solid substrate. The detection of H2O2 could be achieved in wide concentration ranges over 805 nM–1.61 mM and 161 μM–19.32 mM in solution and on a solid membrane, respectively, with limits of detection (LOD of 80 nM and 20 μM. Moreover, the AuNCs-based membrane could also be used for visual detection of H2O2 in the range of 0–3.22 mM. In view of the convenient synthesis route and attractive luminescent properties, the AuNCs-based membrane presented in this work is quite promising for applications such as optical sensing, fluorescent imaging, and photovoltaics.

  9. Novel sulfonated poly (ether ether keton)/polyetherimide acid-base blend membranes for vanadium redox flow battery applications

    International Nuclear Information System (INIS)

    Liu, Shuai; Wang, Lihua; Ding, Yue; Liu, Biqian; Han, Xutong; Song, Yanlin

    2014-01-01

    Highlights: • SPEEK/PEI acid-base blend membranes are prepared for VRB applications. • The acid-base blend membranes have much lower vanadium ion permeability. • The energy efficiency of SPEEK/PEI maintain around 86.9% after 50 cycles. - Abstract: Novel acid-base blend membranes composed of sulfonated poly (ether ether ketone) (SPEEK) and polyetherimide (PEI) were prepared for vanadium redox flow battery (VRB). The blend membranes were characterized by Fourier transform infrared spectroscopy (FT-IR) and scanning electronic microscopy (SEM). The ion exchange capacity (IEC), proton conductivity, water uptake, vanadium ion permeability and mechanical properties were measured. As a result, the acid-base blend membranes exhibit higher water uptake, IEC and lower vanadium ion permeability compared to Nafion117 membranes and all these properties decrease with the increase of PEI. In VRB single cell test, the VRB with blend membranes shows lower charge capacity loss, higher coulombic efficiency (CE) and energy efficiency (EE) than Nafion117 membrane. Furthermore, the acid-base blend membranes present stable performance up to 50 cycles with no significant decline in CE and EE. All experimental results indicate that the SPEEK/PEI (S/P) acid-base blend membranes show promising prospects for VRB

  10. Electrode-analytical properties of polyvinylchloride membranes based on triple metal-polymeric complexes

    Directory of Open Access Journals (Sweden)

    Katerina V. Matorina

    2015-10-01

    Full Text Available The influence of the nature of the electrode-active substances (EAS, the composition of the external and internal solutions on the formation of the analytical signal of polyvinylchloride (PVC membranes based on associates and triple metal-polymeric complexes (TMPC was established. Dehumidification of synthesized membranes increases with the content of polyvinylpyrrolidone (PVP. The value of the swelling degree is more than two times greater for membranes, which contain as EAS TMPC, relative to membranes based on associates. The value of water absorption of membranes is determined by the nature of EAS. They formed a series of increasing of the swelling degree such as associate < background membrane < TMPC. Swelling of the background membrane is explained by the physical sorption of water molecules on the surface of plasticized membrane. Hydration of PVP macromolecules varies with the introduction of metal ions, macromolecules unit undergoes a conformational transition. PVP macromolecules form tunnels or cavities where complex particles distributed and additional water accumulated through the second coordination layer. Constructed sensors based on TMPC have slope of electrode function equal to 25 mV/pC. Linear dependence of potential on the polymer concentration is observed in the range of 5–7 pC units. Sensors based on associates have slope of the electrode function of 20–25 mV/pC that can be varied depending on the nature of the EAS. Working range is 4–8 pC. Response time of sensor is less than 1 min. The optimal time for conditioning of the synthesized PVC membrane is 24 hours. Potentiometric sensors have been developed for the determination of residual amounts of low molecular PVP which is a food additive E 1201 commonly used for thickening, stabilizing and clarifying of food products. The content of PVP was determined in real objects (apple juice, beer, red wine and cognac with using the polyvinylpyrrolidone sensors (Sr < 0.08. The

  11. Types of household humidifier disinfectant and associated risk of lung injury (HDLI) in South Korea.

    Science.gov (United States)

    Park, Dong-Uk; Ryu, Seung-Hun; Lim, Heung-Kyu; Kim, Sun-Kyung; Choi, Ye-Yong; Ahn, Jong-Ju; Lee, Eun; Hong, Sang-Bum; Do, Kyung-Hyun; Cho, Jae-Lim; Bae, Mun-Joo; Shin, Dong-Chun; Paek, Do-Myung; Hong, Soo-Jong

    2017-10-15

    From 2002 through 2015, hundreds of people died of fatal lung injuries associated with the use of humidifier disinfectants (HDs) in Korea. Several chemical disinfectants used for household humidifiers were later clinically confirmed to cause HD-associated lung injury (HDLI). The aim of this study is to evaluate the registered lung disease cases and to compare the distribution of HDLI patients, including deaths, by HD use characteristics including types of HD and HD brands categorized by age group. A total of 530 registered were clinically examined through two rounds of investigations conducted from July 2013 until April 2015. Information on HD use was obtained from a structured questionnaire and home investigations. Approximately one-half of the patients (n=221) were clinically confirmed to be associated with the use of HDs. Pregnant women (n=35, 16%) and pre-school children≤6years old (n=128, 58%) accounted for most of the HD-associated lung injury patients (n=163, 74%). Sixty-seven percent of HDLI patients developed HDLI after less than one year of HD use. HD products containing polyhexamethylene guanidine phosphate (PHMG) were the most frequently used among confirmed HDLI patients (n=123, 55.7%), followed by oligo (2-(2-ethoxy) ethoxyethyl guanidinium (PGH) (n=24, 10.9%) and a mixture of chloromethylisothiazolinone (CMIT) and methylisothiazolinone (MIT) (n=3, 1.4%). Other HDs did not appear to be linked to HDLI. The majority of the HDLI patients (n=85, 38.5%) was found to use only Oxy Saksak® products containing PHMG. The development of HDLI was clinically found to be associated with the use of several HD products containing PHMG and PGH, and to lesser extent, CMIT/MIT. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Humidification performance of humidifying devices for tracheostomized patients with spontaneous breathing: a bench study.

    Science.gov (United States)

    Chikata, Yusuke; Oto, Jun; Onodera, Mutsuo; Nishimura, Masaji

    2013-09-01

    Heat and moisture exchangers (HMEs) are commonly used for humidifying respiratory gases administered to mechanically ventilated patients. While they are also applied to tracheostomized patients with spontaneous breathing, their performance in this role has not yet been clarified. We carried out a bench study to investigate the effects of spontaneous breathing parameters and oxygen flow on the humidification performance of 11 HMEs. We evaluated the humidification provided by 11 HMEs for tracheostomized patients, and also by a system delivering high-flow CPAP, and an oxygen mask with nebulizer heater. Spontaneous breathing was simulated with a mechanical ventilator, lung model, and servo-controlled heated humidifier at tidal volumes of 300, 500, and 700 mL, and breathing frequencies of 10 and 20 breaths/min. Expired gas was warmed to 37°C. The high-flow CPAP system was set to deliver 15, 30, and 45 L/min. With the 8 HMEs that were equipped with ports to deliver oxygen, and with the high-flow CPAP system, measurements were taken when delivering 0 and 3 L/min of dry oxygen. After stabilization we measured the absolute humidity (AH) of inspired gas with a hygrometer. AH differed among HMEs applied to tracheostomized patients with spontaneous breathing. For all the HMEs, as tidal volume increased, AH decreased. At 20 breaths/min, AH was higher than at 10 breaths/min. For all the HMEs, when oxygen was delivered, AH decreased to below 30 mg/L. With an oxygen mask and high-flow CPAP, at all settings, AH exceeded 30 mg/L. None of the HMEs provided adequate humidification when supplemental oxygen was added. In the ICU, caution is required when applying HME to tracheostomized patients with spontaneous breathing, especially when supplemental oxygen is required.

  13. Novel high-performance nanocomposite proton exchange membranes based on poly (ether sulfone)

    Energy Technology Data Exchange (ETDEWEB)

    Hasani-Sadrabadi, Mohammad Mahdi [Polymer Engineering Department, Amirkabir University of Technology, Tehran (Iran); Biomedical Engineering Department, Amirkabir University of Technology, Tehran (Iran); Dashtimoghadam, Erfan; Ghaffarian, Seyed Reza [Polymer Engineering Department, Amirkabir University of Technology, Tehran (Iran); Hasani Sadrabadi, Mohammad Hossein [Faculty of Social and Economics Science, Alzahra University, Tehran (Iran); Heidari, Mahdi [Graduate School of Management and Economics, Sharif University of Technology, Tehran (Iran); Moaddel, Homayoun [Department of Materials Science and Engineering, University of California, Los Angeles, CA (United States)

    2010-01-15

    In the present research, proton exchange membranes based on partially sulfonated poly (ether sulfone) (S-PES) with various degrees of sulfonation were synthesized. It was found that the increasing of sulfonation degree up to 40% results in the enhancement of water uptake, ion exchange capacity and proton conductivity properties of the prepared membranes to 28.1%, 1.59 meq g{sup -1}, and 0.145 S cm{sup -1}, respectively. Afterwards, nanocomposite membranes based on S-PES (at the predetermined optimum sulfonation degree) containing various loading weights of organically treated montmorillonite (OMMT) were prepared via the solution intercalation technique. X-ray diffraction patterns revealed the exfoliated structure of OMMT in the macromolecular matrices. The S-PES nanocomposite membrane with 3.0 wt% of OMMT content showed the maximum selectivity parameter of about 520,000 S s cm{sup -3} which is related to the high conductivity of 0.051 S cm{sup -1} and low methanol permeability of 9.8 x 10{sup -8} cm{sup 2} s{sup -1}. Furthermore, single cell DMFC fuel cell performance test with 4 molar methanol concentration showed a high power density (131 mW cm{sup -2}) of the nanocomposite membrane at the optimum composition (40% of sulfonation and 3.0 wt% of OMMT loading) compared to the Nafion {sup registered} 117 membrane (114 mW cm{sup -2}). Manufactured nanocomposite membranes thanks to their high selectivity, ease of preparation and low cost could be suggested as the ideal candidate for the direct methanol fuel cell applications. (author)

  14. Tröger’s Base Ladder Polymer for Membrane-Based Hydrocarbon Separation

    KAUST Repository

    Alhazmi, Abdulrahman

    2017-05-01

    The use of polymeric membranes for natural gas separation has rapidly increased during the past three decades, particularly for carbon dioxide separation from natural gas. Another valuable application is the separation of heavy hydrocarbons from methane (fuel gas conditioning), more importantly for remote area and off-shore applications. A new potential polymeric membrane that might be utilized for natural gas separations is a Tröger’s base ladder polymer (PIM-Trip-TB-2). This glassy polymeric membrane was synthesized by the polymerization reaction of 9, 10-dimethyl-2,6 (7) diaminotriptycene with dimethoxymethane. In this research, the polymer was selected due to its high surface area and highly interconnected microporous structure. Sorption isotherms of nitrogen (N2), oxygen (O¬2), methane (CH4), carbon dioxide (CO2), ethane (C2H6), propane (C3H8), and n-butane (n-C4H10) were measured at 35 °C over a range of pressures using a Hiden Intelligent Gravimetric Analyzer, IGA. The more condensable gases (C2H6, CO2, C3H8, and n-C4H10) showed high solubility due to their high affinity to the polymer matrix. The permeation coefficients were determined for various gases at 35 °C and pressure difference of 5 bar via the constant-pressure/variable-volume method. The PIM-Trip-TB-2 film exhibited high performance for several high-impact applications, such as O2/N2, H2/N2 and H2/CH4. Also, physical aging for several gases was examined by measuring the permeability coefficients at different periods of time. Moreover, a series of mixed-gas permeation tests was performed using 2 vol.% n-C4H10/98 vol.% CH4 and the results showed similar transport characteristics to other microporous polymers with pores of less than 2 nm. The work performed in this research suggested that PIM-Trip-TB-2 is suitable for the separation of: (i) higher hydrocarbons from methane and (ii) small, non-condensable gases such as O2/N2 and H2/CH4.

  15. Two-Dimensional Metal-Organic Framework Nanosheets for Membrane-Based Gas Separation.

    Science.gov (United States)

    Peng, Yuan; Li, Yanshuo; Ban, Yujie; Yang, Weishen

    2017-08-07

    Metal-organic framework (MOF) nanosheets could serve as ideal building blocks of molecular sieve membranes owing to their structural diversity and minimized mass-transfer barrier. To date, discovery of appropriate MOF nanosheets and facile fabrication of high performance MOF nanosheet-based membranes remain as great challenges. A modified soft-physical exfoliation method was used to disintegrate a lamellar amphiprotic MOF into nanosheets with a high aspect ratio. Consequently sub-10 nm-thick ultrathin membranes were successfully prepared, and these demonstrated a remarkable H 2 /CO 2 separation performance, with a separation factor of up to 166 and H 2 permeance of up to 8×10 -7  mol m -2  s -1  Pa -1 at elevated testing temperatures owing to a well-defined size-exclusion effect. This nanosheet-based membrane holds great promise as the next generation of ultrapermeable gas separation membrane. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Mesoporous Silica Thin Membranes with Large Vertical Mesochannels for Nanosize-Based Separation.

    Science.gov (United States)

    Liu, Yupu; Shen, Dengke; Chen, Gang; Elzatahry, Ahmed A; Pal, Manas; Zhu, Hongwei; Wu, Longlong; Lin, Jianjian; Al-Dahyan, Daifallah; Li, Wei; Zhao, Dongyuan

    2017-09-01

    Membrane separation technologies are of great interest in industrial processes such as water purification, gas separation, and materials synthesis. However, commercial filtration membranes have broad pore size distributions, leading to poor size cutoff properties. In this work, mesoporous silica thin membranes with uniform and large vertical mesochannels are synthesized via a simple biphase stratification growth method, which possess an intact structure over centimeter size, ultrathin thickness (≤50 nm), high surface areas (up to 1420 m 2 g -1 ), and tunable pore sizes from ≈2.8 to 11.8 nm by adjusting the micelle parameters. The nanofilter devices based on the free-standing mesoporous silica thin membranes show excellent performances in separating differently sized gold nanoparticles (>91.8%) and proteins (>93.1%) due to the uniform pore channels. This work paves a promising way to develop new membranes with well-defined pore diameters for highly efficient nanosize-based separation at the macroscale. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Antibacterial activity on electrospun poly(lactide-co-glycolide) based membranes via Magainin II grafting

    Energy Technology Data Exchange (ETDEWEB)

    Yüksel, Emre; Karakeçili, Ayşe, E-mail: akarakecili@eng.ankara.edu.tr

    2014-12-01

    An antimicrobial peptide (AMP), Magainin II (Mag II) was covalently immobilized on poly(lactide-co-glycolide) (PLGA) and PLGA/gelatin electrospun fibrous membranes. The surface immobilization was characterized by X-ray Photoelectron Spectroscopy (XPS). Scanning Electron Microscopy (SEM) and Atomic Force Microscopy studies showed that the surface morphology of the fibers at micron scale was not affected by the immobilization process. The antibacterial activity of the bound Mag II was tested against Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus. Bacterial adhesion tests, SEM and confocal analyses revealed that the attachment and survival of bacteria were inhibited on Mag II functionalized membranes. AMP immobilization strategy was introduced as a new perspective for the modulation of antibacterial properties on PLGA based materials prepared by electrospinning. - Highlights: • PLGA and PLGA/gelatin fibrous membranes were prepared by electrospinning. • Antimicrobial peptide Mag II was successfully immobilized on PLGA based membranes. • The antibacterial activity was tested against E. coli and S. aureus. • Bacterial adhesion was inhibited on Mag II functionalized membranes.

  18. Technetium-99m extraction and transport across tri-n-octylamine-xylene based supported liquid membranes

    International Nuclear Information System (INIS)

    Ashraf Chaudry, M.; Ahmad, B.

    1996-01-01

    The nuclear properties of 99m Tc radionuclide are ideal for organ imaging. Study of the technetium transport across supported liquid membranes has been performed to get data for its separation from other elements. Tri-n-octylamine diluted in xylene was used to constitute the liquid membranes, supported in polypropylene microporous films. Stripping on the product solution side was performed with dilute NaOH solutions. The effect of sulphuric acid, nitric acid and hydrochloric acid in the feed on transport of 99m Tc as TcO 4 - ions has been studied. The permeability of the given ions determined from kinetic activity data has been found to be in the order of PH 2 SO 4 >PHCl>PHNO 3 . The flux values have been calculated based on this permeability data. The increase in carrier concentration has shown an increase in flux and permeability values to a given optimum concentration. The increase in temperature has been found to reduce the transport of Tc ions. The optimum conditions for transport of 99m Tc for the given acid concentration have been determined. Mechanism of Tc ion transport has also been provided based on chemical reactions involved at the membrane interfaces and uptake of Tc ions by the membrane. MoO 4 2- ions do not permeate through membrane under optimum conditions of transport for TcO 4 2 - ions from H 2 SO 4 solution. (author). 12 refs., 20 figs., 1 tab

  19. Freestanding eggshell membrane-based electrodes for high-performance supercapacitors and oxygen evolution reaction.

    Science.gov (United States)

    Geng, Jing; Wu, Hao; Al-Enizi, Abdullah M; Elzatahry, Ahmed A; Zheng, Gengfeng

    2015-09-14

    A type of freestanding, light-weight eggshell membrane-based electrode is demonstrated for supercapacitors and for oxygen evolution reaction (OER) catalysis. As a widely available daily waste, eggshell membranes have unique porous three-dimensional grid-like fibrous structures with relatively high surface area and abundant macropores, allowing for effective conjugation of carbon nanotubes and growth of NiCo2O4 nanowire arrays, an effective supercapacitor material and OER catalyst. The three-dimensional fibrous eggshell membrane frameworks with carbon nanotubes offer efficient pathways for charge transport, and the macropores between adjacent fibers are fully accessible for electrolytes and bubble evolution. As a supercapacitor, the eggshell membrane/carbon nanotube/NiCo2O4 electrode shows high specific capacitances at current densities from 1 to 20 A g(-1), with excellent capacitance retention (>90%) at 10 A g(-1) for over 10,000 cycles. When employed as an OER catalyst, this eggshell membrane-based electrode exhibits an OER onset potential of 1.53 V vs. the reversible hydrogen electrode (RHE), and a stable catalytic current density of 20 mA cm(-2) at 1.65 V vs. the RHE.

  20. Development of metal catalyst impregnation technology for membrane-based oxygen removal system

    International Nuclear Information System (INIS)

    Kim, Mun Soo; Lee, Doo Ho; Kang, Duk Won

    2005-01-01

    Dissolved oxygen(DO) is a primary cause of PWSCC and its content in reactor coolant system in NPPs has been strictly controlled by various DO removal methods. There are several removal methods of DO, such as vacuum degasification, thermal deaeration, and reductive removal by oxygen scavengers. Although the operation principles of vacuum degasification and thermal deaeration are simple, these methods require a lot of energy for operation and show lower efficiency. And these methods have a few handicaps such as temperature, pH, toxicity, high cost of installation and so on. For the purpose of developing the best method for DO removal from make-up water storage tank, it is necessary to overcome the disadvantages of hydrazine treatment. From this point of view, membrane-based oxygen removal system (MORS) has many advantages than other methods for example, friendly environmental process, versatility of operation conditions with high temperature and low pressure, small space, low cost, etc. Recently de-gassing membrane is widely used in power plant's feed water system for DO removal. De-gassing membrane has some advantages; it removes other dissolved gases such as CO2, N2, as well as O2, and is more economical than Catalytic resin-based Oxygen Removal System. In this study, to obtain better efficiency of MORS, we modified the polypropylene (PP) hollow fiber membrane by plasma treatment and ion beam irradiation supported platinum(Pt), palladium(Pd) as metal catalyst on the surface of the membrane

  1. Development of pvc membrane based potentiometric pH sensor using amine type neutral carrier

    International Nuclear Information System (INIS)

    Khan, M.F.

    1999-01-01

    The glass membrane-based pH-electrode has proved its utility over decades. However some limitations are associated with these type of sensors. It can not be used for measuring pH of hydrofluoric acid solution and is difficult to miniaturize for biological applications due to its high resistance and fragility. In the present investigation modified PVC-membranes have been cast by incorporating lipophilic salt tetrabutyl ammonium tetraphenylborate and sodium tetraphenylborate along with electro active compound tri-n-octylamine as neutral carrier. The performance comparison of fabricated pH-sensitive membrane electrode has been carried out regarding their Nernstian slope and life time. The performance comparison of the membrane electrodes fabricated from laboratory grade tri-n-octylamine and those prepared from highly purified ionophore was also carried out. The slopes of the modified membrane electrodes based on pure ionophore were 59 mV/decade H/sup +/ ions and commercial ionophore 54 mV/decade H/sup +/ ions. The linear range was from pH 5-11. In the range of pH 6-10 response was excellent. The measurement of selectivity coefficients for the probable, interfering ions (anions and cations) were also carried out. (author)

  2. Evaluation of castor oil-based polyurethane membranes in rat bone-marrow cell culture.

    Science.gov (United States)

    Cerejo, Sofia de Amorim; Rahal, Sheila Canevese; Lima Neto, João Ferreira de; Voorwald, Fabiana Azevedo; Alvarenga, Fernanda da Cruz Landim e

    2011-10-01

    To evaluate three methods to isolate rats MSCs and to analyze the potential of a castor oil polyurethane base membrane as a scaffold for MSCs. Four male Wistar rats, aged 20-30 days were used. Bone marrow aspirates from femur and tibia were harvested using DMEM high glucose and heparin. The cell culture was performed in three different ways: direct culture and two types of density gradients. After 15 days, was made the 1st passage and analyzed cell viability with markers Hoerscht 33342 and propidium iodide. The MSCs were characterized by surface markers with the aid of flow cytometry. After this, three types of castor oil polyurethane membranes associated with the MSCs were kept on the 6-well plate for 5 days and were analyzed by optical microscopy to confirm cell aggregation and growth. Separation procedures 1 and 2 allowed adequate isolation of MSCs and favored cell growth with the passage being carried out at 70% confluence after 15 days in culture. The cells could not be isolated using procedure 3. When the 3 castor oil polyurethane membrane types were compared it was possible to observe that the growth of MSCs was around 80% in membrane type 3, 20% in type 2, and 10% in type 1. Both Ficoll-Hypaque densities allow isolation of rat MSCs, and especially castor oil-based membrane type 3 may be used as a scaffold for MSCs.

  3. Performance and economics of a Pd-based planar WGS membrane reactor for coal gasification

    International Nuclear Information System (INIS)

    Dolan, M.D.; Donelson, R.; Dave, N.C.

    2010-01-01

    Conceptual 300 tonne per day (tpd) H 2 -from-coal plants have been the subject of several major costing exercises in the past decade. Incorporating conventional high- and low-temperature water-gas-shift (WGS) reactors, amine-based CO 2 removal and PSA-based H 2 purification systems, these studies provide a benchmark against which alternative H 2 -from-coal technologies can be compared. The catalytic membrane reactor (CMR), combining a WGS catalyst and hydrogen-selective metal membrane, can potentially replace the multiple shift and separation stages of a plant based on conventional technology. CMR-based shift and separation offers several major advantages over the conventional approach, including greater-than-equilibrium WGS conversion, the containment of the CO 2 at high-pressure and a reduction in the number of unit processes. To determine capital costs of a WGS CMR-based H 2 -from-coal plant, a prototype planar CMR was constructed and tested with varying catalyst bed depth, residence time and membrane type (commercially-sourced 50 μm Pd or 40 μm Pd-25Ag wt%). Experiments to measure CO conversion, and H 2 flux and yield were conducted at 400 C with a feed pressure of 20 bar H 2 O:C ratio of 3 and a H 2 product pressure of 1 bar. Under the optimum conditions examined (with a 40 μm-thick Pd-25Ag membrane and 2 would be required to provide a throughput of 300 tpd with 85% H 2 yield. The capital cost of the CMR component of the plant would be around $US 180 million (based on current metal prices), of which 73% can be attributed to the cost of the Pd-Ag alloy membranes. Incorporation of a membrane that meets the 2015 US DOE cost and flux targets would offer cost parity, with a plant cost of $US 44 million and a total membrane area of ∝13,000 m 2 . Meeting these performance and cost targets would likely require a shift to very thin Pd-alloy membranes or highly-permeable Group IV, V body-centred-cubic alloys. (author)

  4. Adamantane-based amphiphiles (ADAs) for membrane protein study: importance of a detergent hydrophobic group in membrane protein solubilisation.

    Science.gov (United States)

    Chae, Pil Seok; Bae, Hyoung Eun; Das, Manabendra

    2014-10-21

    We prepared adamantane-containing amphiphiles and evaluated them using a large membrane protein complex in terms of protein solubilisation and stabilization efficacy. These agents were superior to conventional detergents, especially in terms of the membrane protein solubilisation efficiency, implying a new detergent structure-property relationship.

  5. Stable proton-conducting Ca-doped LaNbO4 thin electrolyte-based protonic ceramic membrane fuel cells by in situ screen printing

    International Nuclear Information System (INIS)

    Lin Bin; Wang Songlin; Liu Xingqin; Meng Guangyao

    2009-01-01

    In order to develop a simple and cost-effective route to fabricate protonic ceramic membrane fuel cells (PCMFCs), a stable proton-conducting La 0.99 Ca 0.01 NbO 4 (LCN) thin electrolyte was fabricated on a porous NiO-La 0.5 Ce 0.5 O 1.75 (NiO-LDC) anode by in situ screen printing. The key part of this process is to directly print well-mixed ink of La 2 O 3 , CaCO 3 and Nb 2 O 5 instead of pre-synthesized LCN ceramic powder on the anode substrate. After sintering at 1400 deg. C for 5 h, the full dense electrolyte membrane in the thickness of 20 μm was obtained. A single cell was assembled with (La 0.8 Sr 0.2 ) 0.9 MnO 3-δ -La 0.5 Ce 0.5 O 1.75 (LSM-LDC) as cathode and tested with humidified hydrogen as fuel and static air as oxidant. The open circuit voltage (OCV) and maximum power density respectively reached 0.98 V and 65 mW cm -2 at 800 deg. C. Interface resistance of cell under open circuit condition was also investigated.

  6. Stable proton-conducting Ca-doped LaNbO{sub 4} thin electrolyte-based protonic ceramic membrane fuel cells by in situ screen printing

    Energy Technology Data Exchange (ETDEWEB)

    Lin Bin [USTC Laboratory for Solid State Chemistry and Inorganic Membranes, Department of Materials Science and Engineering, University of Science and Technology of China (USTC), Hefei, 230026, Anhui (China)], E-mail: bin@mail.ustc.edu.cn; Wang Songlin; Liu Xingqin [USTC Laboratory for Solid State Chemistry and Inorganic Membranes, Department of Materials Science and Engineering, University of Science and Technology of China (USTC), Hefei, 230026, Anhui (China); Meng Guangyao [USTC Laboratory for Solid State Chemistry and Inorganic Membranes, Department of Materials Science and Engineering, University of Science and Technology of China (USTC), Hefei, 230026, Anhui (China)], E-mail: mgym@ustc.edu.cn

    2009-06-10

    In order to develop a simple and cost-effective route to fabricate protonic ceramic membrane fuel cells (PCMFCs), a stable proton-conducting La{sub 0.99}Ca{sub 0.01}NbO{sub 4} (LCN) thin electrolyte was fabricated on a porous NiO-La{sub 0.5}Ce{sub 0.5}O{sub 1.75} (NiO-LDC) anode by in situ screen printing. The key part of this process is to directly print well-mixed ink of La{sub 2}O{sub 3}, CaCO{sub 3} and Nb{sub 2}O{sub 5} instead of pre-synthesized LCN ceramic powder on the anode substrate. After sintering at 1400 deg. C for 5 h, the full dense electrolyte membrane in the thickness of 20 {mu}m was obtained. A single cell was assembled with (La{sub 0.8}Sr{sub 0.2}){sub 0.9}MnO{sub 3-{delta}}-La{sub 0.5}Ce{sub 0.5}O{sub 1.75} (LSM-LDC) as cathode and tested with humidified hydrogen as fuel and static air as oxidant. The open circuit voltage (OCV) and maximum power density respectively reached 0.98 V and 65 mW cm{sup -2} at 800 deg. C. Interface resistance of cell under open circuit condition was also investigated.

  7. An AFM-based pit-measuring method for indirect measurements of cell-surface membrane vesicles

    International Nuclear Information System (INIS)

    Zhang, Xiaojun; Chen, Yuan; Chen, Yong

    2014-01-01

    Highlights: • Air drying induced the transformation of cell-surface membrane vesicles into pits. • An AFM-based pit-measuring method was developed to measure cell-surface vesicles. • Our method detected at least two populations of cell-surface membrane vesicles. - Abstract: Circulating membrane vesicles, which are shed from many cell types, have multiple functions and have been correlated with many diseases. Although circulating membrane vesicles have been extensively characterized, the status of cell-surface membrane vesicles prior to their release is less understood due to the lack of effective measurement methods. Recently, as a powerful, micro- or nano-scale imaging tool, atomic force microscopy (AFM) has been applied in measuring circulating membrane vesicles. However, it seems very difficult for AFM to directly image/identify and measure cell-bound membrane vesicles due to the similarity of surface morphology between membrane vesicles and cell surfaces. Therefore, until now no AFM studies on cell-surface membrane vesicles have been reported. In this study, we found that air drying can induce the transformation of most cell-surface membrane vesicles into pits that are more readily detectable by AFM. Based on this, we developed an AFM-based pit-measuring method and, for the first time, used AFM to indirectly measure cell-surface membrane vesicles on cultured endothelial cells. Using this approach, we observed and quantitatively measured at least two populations of cell-surface membrane vesicles, a nanoscale population (<500 nm in diameter peaking at ∼250 nm) and a microscale population (from 500 nm to ∼2 μm peaking at ∼0.8 μm), whereas confocal microscopy only detected the microscale population. The AFM-based pit-measuring method is potentially useful for studying cell-surface membrane vesicles and for investigating the mechanisms of membrane vesicle formation/release

  8. Ultra-thin and strong formvar-based membranes with controlled porosity for micro- and nano-scale systems

    Science.gov (United States)

    Auchter, Eric; Marquez, Justin; Stevens, Garrison; Silva, Rebecca; Mcculloch, Quinn; Guengerich, Quintessa; Blair, Andrew; Litchfield, Sebastian; Li, Nan; Sheehan, Chris; Chamberlin, Rebecca; Yarbro, Stephen L.; Dervishi, Enkeleda

    2018-05-01

    We present a methodology for developing ultra-thin and strong formvar-based membranes with controlled morphologies. Formvar is a thin hydrophilic and oleophilic polymer inert to most chemicals and resistant to radiation. The formvar-based membranes are viable materials as support structures in micro- and macro-scale systems depending on thinness and porosity control. Tunable sub-micron thick porous membranes with 20%–65% porosity were synthesized by controlling the ratios of formvar, glycerol, and chloroform. This synthesis process does not require complex separation or handling methods and allows for the production of strong, thin, and porous formvar-based membranes. An expansive array of these membrane characterizations including chemical compatibility, mechanical responses, wettability, as well as the mathematical simulations as a function of porosity has been presented. The wide range of chemical compatibility allows for membrane applications in various environments, where other polymers would not be suitable. Our formvar-based membranes were found to have an elastic modulus of 7.8 GPa, a surface free energy of 50 mN m‑1 and an average thickness of 125 nm. Stochastic model simulations indicate that formvar with the porosity of ∼50% is the optimal membrane formulation, allowing the most material transfer across the membrane while also withstanding the highest simulated pressure loadings before tearing. Development of novel, resilient and versatile membranes with controlled porosity offers a wide range of exciting applications in the fields of nanoscience, microfluidics, and MEMS.

  9. Synthesis of robust and high-performance aquaporin-based biomimetic membranes by interfacial polymerization-membrane preparation and RO performance characterization

    DEFF Research Database (Denmark)

    Zhao, Yang; Qiu, Changquan; Li, Xuesong

    2012-01-01

    -free ABMs that can be easily scaled up. In the current study, a thin film composite (TFC) ABM was prepared by the interfacial polymerization method, where AquaporinZ-containing proteoliposomes were added to the m-phenylene-diamine aqueous solution. Control membranes, either without aquaporins......Aquaporins are water channel proteins with excellent water permeability and solute rejection, which makes them promising for preparing high-performance biomimetic membranes. Despite the growing interest in aquaporin-based biomimetic membranes (ABMs), it is challenging to produce robust and defect...... or with inactive (mutant) aquaporins, were also similarly prepared. The separation performance of these membranes was evaluated by cross-flow reverse osmosis (RO) tests. Compared to the controls, the active ABM achieved significantly higher water permeability (∼4L/m2hbar) with comparable NaCl rejection (∼97...

  10. Development of immobilized membrane-based affinity columns for use in the online characterization of membrane bound proteins and for targeted affinity isolations

    International Nuclear Information System (INIS)

    Moaddel, Ruin; Wainer, Irving W.

    2006-01-01

    Membranes obtained from cell lines that express or do not express a target membrane bound protein have been immobilized on a silica-based liquid chromatographic support or on the surface of an activated glass capillary. The resulting chromatographic columns have been placed in liquid chromatographic systems and used to characterize the target proteins and to identify small molecules that bind to the target. Membranes containing ligand gated ion channels, G-protein coupled receptors and drug transporters have been prepared and characterized. If a marker ligand has been identified for the target protein, frontal or zonal displacement chromatographic techniques can be used to determine binding affinities (K d values) and non-linear chromatography can be used to assess the association (k on ) and dissociation (k off ) rate constants and the thermodynamics of the binding process. Membrane-based affinity columns have been created using membranes from a cell line that does not express the target protein (control) and the same cell line that expresses the target protein (experimental) after genomic transfection. The resulting columns can be placed in a parallel chromatography system and the differential retention between the control and experimental columns can be used to identify small molecules and protein that bind to the target protein. These applications will be illustrated using columns created using cellular membranes containing nicotinic acetylcholine receptors and the drug transporter P-glycoprotein

  11. Development of immobilized membrane-based affinity columns for use in the online characterization of membrane bound proteins and for targeted affinity isolations

    Energy Technology Data Exchange (ETDEWEB)

    Moaddel, Ruin [Gerontology Research Center, National Institute on Aging, National Institutes of Health, 5600 Nathan Shock Drive, Baltimore, MD 21224-6825 (United States); Wainer, Irving W. [Gerontology Research Center, National Institute on Aging, National Institutes of Health, 5600 Nathan Shock Drive, Baltimore, MD 21224-6825 (United States)]. E-mail: Wainerir@grc.nia.nih.gov

    2006-03-30

    Membranes obtained from cell lines that express or do not express a target membrane bound protein have been immobilized on a silica-based liquid chromatographic support or on the surface of an activated glass capillary. The resulting chromatographic columns have been placed in liquid chromatographic systems and used to characterize the target proteins and to identify small molecules that bind to the target. Membranes containing ligand gated ion channels, G-protein coupled receptors and drug transporters have been prepared and characterized. If a marker ligand has been identified for the target protein, frontal or zonal displacement chromatographic techniques can be used to determine binding affinities (K {sub d} values) and non-linear chromatography can be used to assess the association (k {sub on}) and dissociation (k {sub off}) rate constants and the thermodynamics of the binding process. Membrane-based affinity columns have been created using membranes from a cell line that does not express the target protein (control) and the same cell line that expresses the target protein (experimental) after genomic transfection. The resulting columns can be placed in a parallel chromatography system and the differential retention between the control and experimental columns can be used to identify small molecules and protein that bind to the target protein. These applications will be illustrated using columns created using cellular membranes containing nicotinic acetylcholine receptors and the drug transporter P-glycoprotein.

  12. Ionomeric membranes based on partially sulfonated poly(styrene) : synthesis, proton conduction and methanol permeation

    NARCIS (Netherlands)

    Picchioni, F.; Tricoli, V.; Carretta, N.

    2000-01-01

    Homogeneuosly sulfonated poly(styrene) (SPS) was prepared with various concentration of sulfonic acid groups in the base polymer. Membranes cast from these materials were investigated in relation to proton conductivity and methanol permeability in the temperature range from 20°C to 60°C. It was

  13. Ionomeric membranes based on partially sulfonated poly(styrene): synthesis, proton conduction and methanol permeation

    NARCIS (Netherlands)

    Carretta, N.; Tricoli, V.; Picchioni, F.

    2000-01-01

    Homogeneuosly sulfonated poly(styrene) (SPS) was prepared with various concentration of sulfonic acid groups in the base polymer. Membranes cast from these materials were investigated in relation to proton conductivity and methanol permeability in the temperature range from 20°C to 60°C. It was

  14. Invariant-based inverse engineering for fluctuation transfer between membranes in an optomechanical cavity system

    Science.gov (United States)

    Chen, Ye-Hong; Shi, Zhi-Cheng; Song, Jie; Xia, Yan

    2018-02-01

    In this paper, by invariant-based inverse engineering, we design classical driving fields to transfer quantum fluctuations between two suspended membranes in an optomechanical cavity system. The transfer can be quickly attained through a nonadiabatic evolution path determined by a so-called dynamical invariant. Such an evolution path allows one to optimize the occupancies of the unstable "intermediate" states; thus, the influence of cavity decays can be suppressed. Numerical simulation demonstrates that a perfect fluctuation transfer between two membranes can be rapidly achieved in one step, and the transfer is robust to both the amplitude noises and cavity decays.

  15. Prepare and characterization of nanocomposite - mixed matrix membranes based on polycarbonate

    International Nuclear Information System (INIS)

    Paranhos, Caio M.; Pessan, Luiz A.; Gomes, Ana C. de O.

    2009-01-01

    Mixed matrix membranes based on polycarbonate with different content of sepiolite were prepared by casting. The obtained membranes were characterized by wide-angle X-ray diffraction, thermal analysis, optical transparency and permeation to oxygen. The presence of sepiolite leads to the formation of a polymer-clay interface. The presence of the interface causes the increase in O 2 permeation. Increasing content of sepiolite results in aggregates of sepiolite, which forms preferential channels to the O 2 molecules. This fact is directly related to the strong increasing observed in O 2 permeability. (author)

  16. Microchemical device based on microscopic bilayer lipid membranes; Bisho 2 bunshimaku wo mochiiita maikuro kagaku debaisu

    Energy Technology Data Exchange (ETDEWEB)

    Yokoyama, H. [Electrotechnical Lab., Ibaraki (Japan)

    1996-04-01

    If an organism is regarded as a macromolecular system, the element device to construct the same is the molecular structure of nano meter scale formed by the functional protein existing in biomembranes. A lot of essential functions of organism such as the sense reception including vision, gustation, etc., photosynthesis, energy-substance production and so on are performed therein. In this paper, the structure, preparing process and the functions of the microchemical device using micro-bilipid membranes are described. The simulation of the sense receiving functions of organisms is tried by said microchemical device wherein, same as biomembranes, the base is bilayer lipid molecular membrane and the receptive protein for receiving signals from exterior and output molecules such as ion channels connected to said receptive protein and the like are incorporated in the membranes. Recently, it becomes possible to make a partial imaging of the bilayer lipid membranes fixed on porous membrane by the observation with scanning Maxwell-stress microscope. 4 refs., 3 figs.

  17. Towards high water permeability in triazine-framework-based microporous membranes for dehydration of ethanol.

    Science.gov (United States)

    Tang, Yu Pan; Wang, Huan; Chung, Tai Shung

    2015-01-01

    The microstructural evolution of a series of triazine framework-based microporous (TFM) membranes under different conditions has been explored in this work. The pristine TFM membrane is in situ fabricated in the course of polymer synthesis via a facile Brønsted-acid-catalyzed cyclotrimerizaiton reaction. The as-synthesized polymer exhibits a microporous network with high thermal stability. The free volume size of the TFM membranes gradually evolved from a unimodal distribution to a bimodal distribution under annealing, as analyzed by positron annihilation lifetime spectroscopy (PALS). The emergence of the bimodal distribution is probably ascribed to the synergetic effect of quenching and thermal cyclization reaction. In addition, the fractional free volume (FFV) of the membranes presents a concave trend with increasing annealing temperature. Vapor sorption tests reveal that the mass transport properties are closely associated with the free volume evolution, which provides an optimal condition for dehydration of biofuels. A promising separation performance with extremely high water permeability has been attained for dehydration of an 85 wt % ethanol aqueous solution at 45 °C. The study on the free volume evolution of the TFM membranes may provide useful insights about the microstructure and mass transport behavior of the microporous polymeric materials. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Efficient adhesion-based plasma membrane isolation for cell surface N-glycan analysis.

    Science.gov (United States)

    Mun, Ji-Young; Lee, Kyung Jin; Seo, Hoon; Sung, Min-Sun; Cho, Yee Sook; Lee, Seung-Goo; Kwon, Ohsuk; Oh, Doo-Byoung

    2013-08-06

    Glycans, which decorate cell surfaces, play crucial roles in various physiological events involving cell surface recognition. Despite the importance of surface glycans, most analyses have been performed using total cells or whole membranes rather than plasma membranes due to difficulties related to isolation. In the present study, we employed an adhesion-based method for plasma membrane isolation to analyze N-glycans on cell surfaces. Cells were attached to polylysine-coated glass plates and then ruptured by hypotonic pressure. After washing to remove intracellular organelles, only a plasma membrane fraction remained attached to the plates, as confirmed by fluorescence imaging using organelle-specific probes. The plate was directly treated with trypsin to digest and detach the glycoproteins from the plasma membrane. From the resulting glycopeptides, N-glycans were released and analyzed using MALDI-TOF mass spectrometry and HPLC. When N-glycan profiles obtained by this method were compared to those by other methods, the amount of high-mannose type glycans mainly contaminated from the endoplasmic reticulum was dramatically reduced, which enabled the efficient detection of complex type glycans present on the cell surface. Moreover, this method was successfully used to analyze the increase of high-mannose glycans on the surface as induced by a mannosidase inhibitor treatment.

  19. Triple-bore hollow fiber membrane contactor for liquid desiccant based air dehumidification

    KAUST Repository

    Bettahalli Narasimha, Murthy Srivatsa

    2016-04-26

    Dehumidification is responsible for a large part of the energy consumption in cooling systems in high humidity environments worldwide. Improving efficiency is therefore essential. Liquid desiccants offer a promising solution for dehumidification, as desired levels of humidity removal could be easily regulated. The use of membrane contactors in combination with liquid desiccant is attractive for dehumidification because they prevent direct contact between the humid air and the desiccant, removing both the potential for desiccant carryover to the air and the potential for contamination of the liquid desiccant by dust and other airborne materials, as well as minimizing corrosion. However, the expected additional mass transport barrier of the membrane surface can lower the expected desiccation rate per unit of desiccant surface area. In this context, hollow fiber membranes present an attractive option for membrane liquid desiccant contactors because of their high surface area per unit volume. We demonstrate in this work the performance of polyvinylidene fluoride (PVDF) based triple-bore hollow fiber membranes as liquid desiccant contactors, which are permeable to water vapor but impermeable to liquid water, for dehumidification of hot and humid air.

  20. DEVELOPMENT OF A UREA BIOSENSOR BASED ON A POLYMERIC MEMBRANE INCLUDING ZEOLITE

    Directory of Open Access Journals (Sweden)

    M. L HAMLAOUI

    2008-06-01

    + -sensitive membrane is based on a zeolite-incorporated polymeric membrane biosensor (clinoptilolite. The sensitivity of ammonium  detection is sub-nernstian (32mV/pNH4 + but the ISFET presents a high selectivity, which is interesting for measurements in biological media. The grafting of urease to the NH4 +-sensitive membrane was permorfed by cross-linking with glutaraldehyde .The sensitivity of the urea ENFET is 15V/purea and this remains stable over 15 days with a detection limit of 3x10-5 M. Finally, in order to test feasibility of the urea biosensor for environmental applications, the remaining activity of the urease was determined after exposure to enzyme inhibiting heavy metals ions such as Hg(II.Using these urea biosensors, a detection limit of less than 5 x 10-8 M was obtained for Hg(II.

  1. Properties of the Nafion membrane impregnated with hydroxyl ammonium based ionic liquids

    International Nuclear Information System (INIS)

    Garaev, Valeriy; Pavlovica, Sanita; Vaivars, Guntars; Kleperis, Janis

    2012-01-01

    In this work, the Nafion 112 membrane impregnated with nine various hydroxyl ammonium based ionic liquids have been investigated. The used ionic liquids were combined from hydroxyl ammonium cations (2-hydroxyethylammonium/HEA, bis(2- hydroxyethyl)ammonium/BHEA, tris(2-hydroxyethyl)ammonium/THEA) and carboxylate anions (formate, acetate, lactate). The membranes are characterized by conductivity and thermal stability measurements. It was found, that almost all composites have 10 times higher ion conductivity than a pure Nafion 112 at 90 °C in ambient environment due to the higher thermal stability. The thermal stability of Nafion membrane was increased by all studied nine ionic liquids. In this work, only biodegradable ionic liquids were used for composite preparation.

  2. Paper membrane-based SERS platform for the determination of glucose in blood samples.

    Science.gov (United States)

    Torul, Hilal; Çiftçi, Hakan; Çetin, Demet; Suludere, Zekiye; Boyacı, Ismail Hakkı; Tamer, Uğur

    2015-11-01

    In this report, we present a paper membrane-based surface-enhanced Raman scattering (SERS) platform for the determination of blood glucose level using a nitrocellulose membrane as substrate paper, and the microfluidic channel was simply constructed by wax-printing method. The rod-shaped gold nanorod particles were modified with 4-mercaptophenylboronic acid (4-MBA) and 1-decanethiol (1-DT) molecules and used as embedded SERS probe for paper-based microfluidics. The SERS measurement area was simply constructed by dropping gold nanoparticles on nitrocellulose membrane, and the blood sample was dropped on the membrane hydrophilic channel. While the blood cells and proteins were held on nitrocellulose membrane, glucose molecules were moved through the channel toward the SERS measurement area. Scanning electron microscopy (SEM) was used to confirm the effective separation of blood matrix, and total analysis is completed in 5 min. In SERS measurements, the intensity of the band at 1070 cm(-1) which is attributed to B-OH vibration decreased depending on the rise in glucose concentration in the blood sample. The glucose concentration was found to be 5.43 ± 0.51 mM in the reference blood sample by using a calibration equation, and the certified value for glucose was 6.17 ± 0.11 mM. The recovery of the glucose in the reference blood sample was about 88 %. According to these results, the developed paper-based microfluidic SERS platform has been found to be suitable for use for the detection of glucose in blood samples without any pretreatment procedure. We believe that paper-based microfluidic systems may provide a wide field of usage for paper-based applications.

  3. Physically Gelled Room-Temperature Ionic Liquid-Based Composite Membranes for CO2/N-2 Separation: Effect of Composition and Thickness on Membrane Properties and Performance

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, PT; Voss, BA; Wiesenauer, EF; Gin, DL; Nobe, RD

    2013-07-03

    An aspartame-based, low molecular-weight organic gelator (LMOG) was used to form melt-infused and composite membranes with two different imidazolium-based room-temperature ionic liquids (RTILs) for CO2 separation from N-2. Previous work demonstrated that LMOGs can gel RTILs at low, loading levels, and this aspartame-based LMOG was selected because it has been reported to gel a large number of RTILs. The imidazolium-based RTILs were used because of their inherent good properties for CO2/light gas separations. Analysis of the resulting bulk RTIL/LMOG physical gels showed that these materials have high sol-gel transition temperatures (ca. 135 degrees C) suitable for flue gas applications. Gas permeabilities and burst pressure measurements of thick, melt infused membranes revealed a trade-off between high CO2 permeabilities and good mechanical stability as a function of the LMOG loading. Defect-free, composite membranes of the gelled RTILs were successfully fabricated by choosing an appropriate porous membrane support (hydrophobic PTFE) using a suitable coating technique (roller coating). The thicknesses of the applied composite gel layers ranged from 10.3 to 20.7 mu m, which represents an order of magnitude decrease in active layer thickness, compared to the original melt-infused gel RTIL membranes.

  4. A process synthesis-intensification framework for the development of sustainable membrane-based operations

    DEFF Research Database (Denmark)

    Babi, Deenesh Kavi; Lutze, Philip; Woodley, John

    2014-01-01

    In this paper a multi-level, multi-scale framework for process synthesis-intensification that aims to make the process more sustainable than a base-case, which may represent a new process or an existing process, is presented. At the first level (operation-scale) a conceptual base case design...... of extension of the combined intensification-synthesis method and its application to generate membrane-based operations. Also, application of the framework is illustrated through a case study involving the production of methyl acetate where membrane-based intensified operations play a major role in determining...... is synthesized through the sequencing of unit operations and subsequently analyzed for identifying process hot-spots using economic, life cycle and sustainability metrics. These hot-spots are limitations/bottlenecks associated with tasks that may be targeted for overall process improvement. At the second level...

  5. Cross flow microfiltration of oil-water emulsions using clay based ceramic membrane support and TiO2 composite membrane

    Directory of Open Access Journals (Sweden)

    Kanchapogu Suresh

    2017-09-01

    Full Text Available The main objective of this work is to study the effect of cross flow filtration conditions on the separation of oily wastewater using ceramic support and TiO2 membrane. Firstly, the low cost clay based ceramic membrane support was prepared by uniaxial compaction method using combination of pyrophyllite, quartz, feldspar, kaolin, ball clay and calcium carbonate along with PVA as a binder. Subsequently, TiO2 composite membrane was fabricated via hydrothermal route employing TiO2 sol derived from TiCl4 and NH4OH solution. Cross flow microfiltration investigations were carried out by utilizing oil-water emulsion concentration of 200 mg/L at three distinct applied pressures (69–207 kPa and three cross flow velocities (0.0885, 0.1327, and 0.1769 m/s. Compared to ceramic support, TiO2 composite membrane demonstrates better performance in terms of flux and removal efficiency of oil and also the rate of flux decline during filtration operation is lower due to highly hydrophilic surface of the TiO2 membrane. TiO2 membrane displays the oil removal efficiency of 99% in the entire range of applied pressures investigation, while ceramic support shows 93–96% of oil removal.

  6. Tröger’s Base Ladder Polymer for Membrane-Based Hydrocarbon Separation

    KAUST Repository

    Alhazmi, Abdulrahman

    2017-01-01

    The use of polymeric membranes for natural gas separation has rapidly increased during the past three decades, particularly for carbon dioxide separation from natural gas. Another valuable application is the separation of heavy hydrocarbons from

  7. Calculations of helium separation via uniform pores of stanene-based membranes

    Directory of Open Access Journals (Sweden)

    Guoping Gao

    2015-12-01

    Full Text Available The development of low energy cost membranes to separate He from noble gas mixtures is highly desired. In this work, we studied He purification using recently experimentally realized, two-dimensional stanene (2D Sn and decorated 2D Sn (SnH and SnF honeycomb lattices by density functional theory calculations. To increase the permeability of noble gases through pristine 2D Sn at room temperature (298 K, two practical strategies (i.e., the application of strain and functionalization are proposed. With their high concentration of large pores, 2D Sn-based membrane materials demonstrate excellent helium purification and can serve as a superior membrane over traditionally used, porous materials. In addition, the separation performance of these 2D Sn-based membrane materials can be significantly tuned by application of strain to optimize the He purification properties by taking both diffusion and selectivity into account. Our results are the first calculations of He separation in a defect-free honeycomb lattice, highlighting new interesting materials for helium separation for future experimental validation.

  8. Reclamation from palm oil mill effluent using an integrated zero discharge membrane-based process

    Directory of Open Access Journals (Sweden)

    Ahmad A.L.

    2015-12-01

    Full Text Available This research emphasizes eloquently on membrane technology for treatment of palm oil mill effluent (POME as it is the Malaysia’s largest and most important agro based industry. Findings established significant quality improvement with an efficient recovery of water from palm oil mill via innovative membrane application. Conventional bio-methods, whilst adhering to the Department of Environment’s (DOE discharge regulations, produces brownish liquid which pales in comparison to the crystal clear water obtained through membrane treatment. The pre-treatment process consists of coagulation-flocculation using green environmental coagulant bases such as Moringa oleifera (MO seeds. The ultrafiltration polyvinylidene difluoride (PVDF and thin film composite (TFC reverse osmosis were vital for the membrane processes. The system gave 99% suspended solids reduction in suspended solid and 78% of water present was successfully recovered. This technology guarantees water recovery with drinking water quality; meeting the US Environmental Protection Agency (USEPA standard or could be recycled into the plant with sludge utilization for palm oil estates, thus enabling the concept of zero discharge to be executed in the industries. In addition, green and healthy antioxidants such as oil and beta-carotene can be recovered from POME further demonstrate. Silica gel showed better performance in separation of carotenes from oil at temperature 40°C using adsorption chromatography with 1154.55 ppm. The attractiveness of this technology, enabling the utilization of reuse of agricultural waste into potentially value added products.

  9. Electrospun polyimide-based fiber membranes as polymer electrolytes for lithium-ion batteries

    International Nuclear Information System (INIS)

    Wang, Qiujun; Song, Wei-Li; Wang, Luning; Song, Yu; Shi, Qiao; Fan, Li-Zhen

    2014-01-01

    Polymer electrolytes based on electrospun polyimide (PI) membranes are incorporated with electrolyte solution containing 1 mol L −1 LiPF 6 /ethylene carbonate/ethylmethyl carbonate/dimethyl carbonate to examine their potential application for lithium ion batteries. The as-electrospun non-woven membranes demonstrate a uniformly interconnected structure with an average fiber diameter of 800 nm. The membranes, showing superior thermal stability and flame retardant property compared to the commercial Celgard® membranes, exhibit high porosity and high uptake when activated with the liquid electrolyte. The resulting PI electrolytes (PIs) have a high ionic conductivity up to 2.0 × 10 −3 S cm −1 at 25 °C, and exhibit a high electrochemical stability potential more than 5.0 V (vs. Li/Li + ). They also possess excellent charge/discharge performance and capacity retention. The initial discharge capacities of the Li/PIs/Li 4 Ti 5 O 12 cells are 178.4, 167.4, 160.3, 148.3 and 135.9 mAh g −1 at the charge/discharge rates of 0.2 C, 1 C, 2 C, 5 C and 10 C, respectively. After 200 cycles at 5 C, a capacity around ∼146.8 mAh g −1 can be still achieved. The PI-based polymer electrolytes with strong mechanical properties and good electrochemical performance are proved to be promising electrolytes for lithium ion batteries

  10. Crosslinked anion exchange membranes with primary diamine-based crosslinkers for vanadium redox flow battery application

    Science.gov (United States)

    Cha, Min Suc; Jeong, Hwan Yeop; Shin, Hee Young; Hong, Soo Hyun; Kim, Tae-Ho; Oh, Seong-Geun; Lee, Jang Yong; Hong, Young Taik

    2017-09-01

    A series of polysulfone-based crosslinked anion exchange membranes (AEMs) with primary diamine-based crosslinkers has been prepared via simple a crosslinking process as low-cost and durable membranes for vanadium redox flow batteries (VRFBs). Chloromethylated polysulfone is used as a precursor polymer for crosslinked AEMs (CAPSU-x) with different degrees of crosslinking. Among the developed AEMs, CAPSU-2.5 shows outstanding dimensional stability and anion (Cl-, SO42-, and OH-) conductivity. Moreover, CAPSU-2.5 exhibits much lower vanadium ion permeability (2.72 × 10-8 cm2 min-1) than Nafion 115 (2.88 × 10-6 cm2 min-1), which results in an excellent coulombic efficiency of 100%. The chemical and operational stabilities of the membranes have been investigated via ex situ soaking tests in 0.1 M VO2+ solution and in situ operation tests for 100 cycles, respectively. The excellent chemical, physical, and electrochemical properties of the CAPSU-2.5 membrane make it suitable for use in VRFBs.

  11. PROTECTIVE CLOTHING BASED ON PERMSELECTIVE MEMBRANE AND CARBON ADSORPTION

    Energy Technology Data Exchange (ETDEWEB)

    J.G. Wijmans; J.O. Stull

    2001-11-07

    . Protective suits were prepared in collaboration with Kimberly-Clark Corporation and heat stress testing with human test subjects was carried out by the International Union of Operating Engineers (IUOE). The tests confirmed that the MTR protective fabric is significantly more comfortable than non-breathable materials. A cost analysis was developed from the properties of the optimized protective fabric and the results of the of the IUOE field study to determine the potential for the MTR material technology within the chemical protective clothing market. A detailed assessment of the specific chemical protective clothing applications for which the material can be used and its competitiveness with existing material technology, based both on expected performance and material/end item costs, was prepared. Three specific market opportunities identified for the novel protective fabric are: (1) liquid splash protective clothing for hazardous waste site operations, (2) liquid splash protective clothing for emergency response, and (3) Class 3 NFPA 1994-compliant protective clothing for civilian use during chemical terrorism incidents.

  12. PROTECTIVE CLOTHING BASED ON PERMSELECTIVE MEMBRANE AND CARBON ADSORPTION

    International Nuclear Information System (INIS)

    Wijmans, J.G.; Stull, J.O.

    2001-01-01

    . Protective suits were prepared in collaboration with Kimberly-Clark Corporation and heat stress testing with human test subjects was carried out by the International Union of Operating Engineers (IUOE). The tests confirmed that the MTR protective fabric is significantly more comfortable than non-breathable materials. A cost analysis was developed from the properties of the optimized protective fabric and the results of the of the IUOE field study to determine the potential for the MTR material technology within the chemical protective clothing market. A detailed assessment of the specific chemical protective clothing applications for which the material can be used and its competitiveness with existing material technology, based both on expected performance and material/end item costs, was prepared. Three specific market opportunities identified for the novel protective fabric are: (1) liquid splash protective clothing for hazardous waste site operations, (2) liquid splash protective clothing for emergency response, and (3) Class 3 NFPA 1994-compliant protective clothing for civilian use during chemical terrorism incidents

  13. Gas Separation Performance of Carbon Molecular Sieve Membranes Based on 6FDA-mPDA/DABA (3:2) Polyimide

    KAUST Repository

    Qiu, Wulin

    2014-02-23

    6FDA-mPDA/DABA (3:2) polyimide was synthesized and characterized for uncross-linked, thermally crosslinked, and carbon molecular sieve (CMS) membranes. The membranes were characterized with thermogravimetric analysis, FTIR spectroscopy, wide-angle X-ray diffraction, and gas permeation tests. Variations in the d spacing, the formation of pore structures, and changes in the pore sizes of the CMS membranes were discussed in relation to pyrolysis protocols. The uncross-linked polymer membranes showed high CO 2/CH4 selectivity, whereas thermally crosslinked membranes exhibited significantly improved CO2 permeability and excellent CO2 plasticization resistance. The CMS membranes showed even higher CO2 permeability and CO2/CH4 selectivity. An increase in the pyrolysis temperature resulted in CMS membranes with lower gas permeability but higher selectivity. The 550 °C pyrolyzed CMS membranes showed CO2 permeability as high as 14 750 Barrer with CO 2/CH4 selectivity of approximately 52. Even 800 °C pyrolyzed CMS membranes still showed high CO2 permeability of 2610 Barrer with high CO2/CH4 selectivity of approximately 118. Both polymer membranes and the CMS membranes are very attractive in aggressive natural gas purification applications. Permeating through: Polyimide-based uncross-linked, thermally crosslinked, and carbon molecular sieve (CMS) membranes are prepared. Variations in the d spacing, the formation of pore structures, and changes in the pore sizes of the CMS membranes are discussed in relation to pyrolysis protocols. Both the polymer and CMS membranes are very attractive in aggressive natural gas purification applications. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Heat Exchanger/Humidifier Trade Study and Conceptual Design for the Constellation Space Suit Portable Life Support System Ventilation Subsystem

    Science.gov (United States)

    Paul, Heather L.; Sompayrac, Robert; Conger, Bruce; Chamberlain, Mateo

    2009-01-01

    As development of the Constellation Space Suit Element progresses, designing the most effective and efficient life support systems is critical. The baseline schematic analysis for the Portable Life Support System (PLSS) indicates that the ventilation loop will need some method of heat exchange and humidification prior to entering the helmet. A trade study was initiated to identify the challenges associated with conditioning the spacesuit breathing gas stream for temperature and water vapor control, to survey technological literature and resources on heat exchanger and humidifiers to provide solutions to the problems of conditioning the spacesuit breathing gas stream, and to propose potential candidate technologies to perform the heat exchanger and humidifier functions. This paper summarizes the results of this trade study and also describes the conceptual designs that NASA developed to address these issues.

  15. MStern Blotting–High Throughput Polyvinylidene Fluoride (PVDF) Membrane-Based Proteomic Sample Preparation for 96-Well Plates*

    OpenAIRE

    Berger, Sebastian T.; Ahmed, Saima; Muntel, Jan; Cuevas Polo, Nerea; Bachur, Richard; Kentsis, Alex; Steen, Judith; Steen, Hanno

    2015-01-01

    We describe a 96-well plate compatible membrane-based proteomic sample processing method, which enables the complete processing of 96 samples (or multiples thereof) within a single workday. This method uses a large-pore hydrophobic PVDF membrane that efficiently adsorbs proteins, resulting in fast liquid transfer through the membrane and significantly reduced sample processing times. Low liquid transfer speeds have prevented the useful 96-well plate implementation of FASP as a widely used mem...

  16. New Polymer Electrolyte Membranes Based on Acid Doped PBI For Fuel Cells Operating above 100°C

    DEFF Research Database (Denmark)

    Li, Qingfeng

    2003-01-01

    The technical achievement and challenges for the PEMFC technology based on perfluorosulfonic acid (PFSA) polymer membranes (e.g. Nafion®) are briefly discussed. The newest development for alternative polymer electrolytes for operation above 100°C. As one of the successful approaches to high...... operational temperatures, the development and evaluation of acid doped PBI membranes are reviewed, covering polymer synthesis, membrane casting, acid doping, physiochemical characterization and fuel cell tests....

  17. Nanostructure-based proton exchange membrane for fuel cell applications at high temperature.

    Science.gov (United States)

    Li, Junsheng; Wang, Zhengbang; Li, Junrui; Pan, Mu; Tang, Haolin

    2014-02-01

    As a clean and highly efficient energy source, the proton exchange membrane fuel cell (PEMFC) has been considered an ideal alternative to traditional fossil energy sources. Great efforts have been devoted to realizing the commercialization of the PEMFC in the past decade. To eliminate some technical problems that are associated with the low-temperature operation (such as catalyst poisoning and poor water management), PEMFCs are usually operated at elevated temperatures (e.g., > 100 degrees C). However, traditional proton exchange membrane (PEM) shows poor performance at elevated temperature. To achieve a high-performance PEM for high temperature fuel cell applications, novel PEMs, which are based on nanostructures, have been developed recently. In this review, we discuss and summarize the methods for fabricating the nanostructure-based PEMs for PEMFC operated at elevated temperatures and the high temperature performance of these PEMs. We also give an outlook on the rational design and development of the nanostructure-based PEMs.

  18. The theoretical advantage of affinity membrane-based immunoadsorption therapy of hypercholesterolemia

    International Nuclear Information System (INIS)

    Green, P.; Odell, R.; Schindhelm, K.

    1996-01-01

    Full text: Therapy of hypercholesterolemia using immunoadsorption of Low Density Lipoprotein (LDL) to a gel substrate is a current clinical technique (Bosch T., Biomat., Art. Cells and Immob. Biotech, 20: 1165- 1169, 1992). Recently, Affinity Membranes have been proposed as an alternate substrate for immunoadsorption (Brandt S and others, Bio Technology, 6:779-782, 1988). Potentially, the overall rate of adsorption to a membrane may be faster than to a gel because of the different geometry (ibid). This implies that for the same conditions, a membrane-based device will have a higher Number of Transfer Units, more efficient adsorption and a smaller device size than a gel. To test this hypothesis, we calculated two key theoretical design parameters: Separation Factor, R, and the Number of Transfer Units, N, for a functioning clinical-scale affinity membrane device: R=K d /K d +C 0 . Kd: Equilibrium Dissociation Constant (M) and Co: Feed Concentration (M) N=k a Q max V m /F. ka: Intrinsic reaction rate constant (M -1 min -1 ), Qmax: Substrate capacity (M), Vm: Membrane volume (m1) and F: Flow Rate (m1 min -1 ). We assumed 1 hr treatment time during which 1 plasma volume (3L) is treated, hence F=50 (m1 min -1 ). If we assume 2/3 of LDL is removed from an initial level of 3 g/L, we can calculate an average feed concentration Co = 2 g / L. There is some data available in the literature for typical values of Kd (10 -8 M) and ka ( 10 3 M -1 s -1 to 3 x 10 5 M -1 s -1 ) (Olsen WC and others, Molec. Immun: 26: 129-136, 1989). Since the intrinsic reaction kinetics may vary from very slow (10 3 M) to very fast (3 x 10 5 M), the Number of Transfer Units, N may vary from small (2) to large (650). Hence for a membrane device, we must select the antibody with the fastest reaction, ka, and highest capacity (Qmax) otherwise, there may be no advantage in a membrane-based device over a gel-based device

  19. Novel Water Treatment Processes Based on Hybrid Membrane-Ozonation Systems: A Novel Ceramic Membrane Contactor for Bubbleless Ozonation of Emerging Micropollutants

    Directory of Open Access Journals (Sweden)

    Stylianos K. Stylianou

    2015-01-01

    Full Text Available The aim of this study is the presentation of novel water treatment systems based on ozonation combined with ceramic membranes for the treatment of refractory organic compounds found in natural water sources such as groundwater. This includes, firstly, a short review of possible membrane based hybrid processes for water treatment from various sources. Several practical and theoretical aspects for the application of hybrid membrane-ozonation systems are discussed, along with theoretical background regarding the transformation of target organic pollutants by ozone. Next, a novel ceramic membrane contactor, bringing into contact the gas phase (ozone and water phase without the creation of bubbles (bubbleless ozonation, is presented. Experimental data showing the membrane contactor efficiency for oxidation of atrazine, endosulfan, and methyl tert-butyl ether (MTBE are shown and discussed. Almost complete endosulfan degradation was achieved with the use of the ceramic contactor, whereas atrazine degradation higher than 50% could not be achieved even after 60 min of reaction time. Single ozonation of water containing MTBE could not result in a significant MTBE degradation. MTBE mineralization by O3/H2O2 combination increased at higher pH values and O3/H2O2 molar ratio of 0.2 reaching a maximum of around 65%.

  20. Fabrication and Scale-up of Polybenzimidazole (PBI) Membrane Based System for Precombustion-Based Capture of Carbon Dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Krishnan, Gopala; Jayaweera, Indira; Sanjrujo, Angel; O' Brien, Kevin; Callahan, Richard; Berchtold, Kathryn; Roberts, Daryl-Lynn; Johnson, Will

    2012-03-31

    The primary objectives of this project are to (1) demonstrate the performance and fabrication of a technically and economically viable pre-combustion-based CO{sub 2} capture system based on the high temperature stability and permeance of PBI membranes, (2) optimize a plan for integration of PBI capture system into an IGCC plant and (3) develop a commercialization plan that addresses technical issues and business issues to outline a clear path for technology transfer of the PBI membrane technology. This report describes research conducted from April 1, 2007 to March 30, 2012 and focused on achieving the above objectives. PBI-based hollow fibers have been fabricated at kilometer lengths and bundled as modules at a bench-scale level for the separation of CO{sub 2} from H{sub 2} at high temperatures and pressures. Long term stability of these fibers has been demonstrated with a relatively high H{sub 2}/CO{sub 2} selectivity (35 to 50) and H{sub 2} permeance (80 GPU) at temperatures exceeding 225°C. Membrane performance simulations and systems analysis of an IGCC system incorporating a PBI hollow fiber membrane modules have demonstrated that the cost of electricity for CO{sub 2} capture (<10%) using such a high temperature separator. When the cost of transporting, storing, and monitoring the CO{sub 2} is accounted for, the increase in the COE is only 14.4%.

  1. Efficacy of oligodynamic metals in the control of bacteria growth in humidifier water tanks and mist droplets.

    Science.gov (United States)

    Collart, David; Mehrabi, Sharifeh; Robinson, Liah; Kepner, Bryan; Mintz, Eric A

    2006-06-01

    Antimicrobial capsules were evaluated for their effectiveness to control bacterial contamination of cool mist humidifiers. These capsules contain a mixture of silver and copper promoted alumina beads designed to release low concentrations of these oligodynamic metals into the reservoir water for bacteria control. The reservoir water and mist droplets from the humidifier units were tested for the presence of bacteria over a three-week period. A control unit (without capsule) showed significant bacterial contamination by day three, which increased throughout the three-week test period, in both the reservoir and mist droplets, whereas the antimicrobial capsules reduced contamination during the first week, and minimized the presence of bacteria, in both the reservoir water and mist droplets, to less than 2% of the control unit throughout the three-week test period. It was also observed that, after each inactive weekend, the initial discharge of bacteria via the mist droplets in the control unit was significantly higher than during daily use. However, initial bacterial discharge from the test unit following weekend inactivity never exceeded 0.5% of the control unit. In conclusion, these capsules containing oligodynamic metals are effective in controlling bacteria growth in humidifier water tanks and mist droplets.

  2. A novel crosslinking strategy for preparing poly(vinyl alcohol)-based proton-conducting membranes with high sulfonation

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, Chun-En [Nanoelectrochemistry Laboratory, Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei 106 (China); Lin, Chi-Wen [Department of Chemical Engineering, National Yunlin University of Science and Technology, Yunlin (China); Hwang, Bing-Joe [Nanoelectrochemistry Laboratory, Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei 106 (China); National Synchrotron Radiation Research Center, Hsinchu 300 (China)

    2010-04-15

    This study synthesizes poly(vinyl alcohol) (PVA)-based polymer electrolyte membranes by a two-step crosslinking process involving esterization and acetal ring formation reactions. This work also uses sulfosuccinic acid (SSA) as the first crosslinking agent to form an inter-crosslinked structure and a promoting sulfonating agent. Glutaraldehyde (GA) as the second crosslinking agent, reacts with the spare OH group of PVA and forms, not only a dense structure at the outer membrane surface, but also a hydrophobic protective layer. Compared with membranes prepared by a traditional one-step crosslinking process, membranes prepared by the two-step crosslinking process exhibit excellent dissolution resistance in water. The membranes become water-insoluble even at a molar ratio of SO{sub 3}H/PVA-OH as high as 0.45. Moreover, the synthesized membranes also exhibit high proton conductivities and high methanol permeability resistance. The current study measures highest proton conductivity of 5.3 x 10{sup -2} S cm{sup -1} at room temperature from one of the synthesized membranes, higher than that of the Nafion {sup registered} membrane. Methanol permeability of the synthesized membranes measures about 1 x 10{sup -7} cm{sup 2} S{sup -1}, about one order of magnitude lower than that of the Nafion {sup registered} membrane. (author)

  3. Permeabilization assay for antimicrobial peptides based on pore-spanning lipid membranes on nanoporous alumina.

    Science.gov (United States)

    Neubacher, Henrik; Mey, Ingo; Carnarius, Christian; Lazzara, Thomas D; Steinem, Claudia

    2014-04-29

    Screening tools to study antimicrobial peptides (AMPs) with the aim to optimize therapeutic delivery vectors require automated and parallelized sampling based on chip technology. Here, we present the development of a chip-based assay that allows for the investigation of the action of AMPs on planar lipid membranes in a time-resolved manner by fluorescence readout. Anodic aluminum oxide (AAO) composed of cylindrical pores with a diameter of 70 nm and a thickness of up to 10 μm was used as a support to generate pore-spanning lipid bilayers from giant unilamellar vesicle spreading, which resulted in large continuous membrane patches sealing the pores. Because AAO is optically transparent, fluid single lipid bilayers and the underlying pore cavities can be readily observed by three-dimensional confocal laser scanning microscopy (CLSM). To assay the membrane permeabilizing activity of the AMPs, the translocation of the water-soluble dyes into the AAO cavities and the fluorescence of the sulforhodamine 101 1,2-dihexadecanoyl-sn-glycero-3-phosphoethanol-l-amine triethylammonium salt (Texas Red DHPE)-labeled lipid membrane were observed by CLSM in a time-resolved manner as a function of the AMP concentration. The effect of two different AMPs, magainin-2 and melittin, was investigated, showing that the concentrations required for membrane permeabilization and the kinetics of the dye entrance differ significantly. Our results are discussed in light of the proposed permeabilization models of the two AMPs. The presented data demonstrate the potential of this setup for the development of an on-chip screening platform for AMPs.

  4. Acid and base recovery from brine solution using PVP intermediate-based bipolar membrane through water splitting technology

    Science.gov (United States)

    Venugopal, Krishnaveni; Murugappan, Minnoli; Dharmalingam, Sangeetha

    2017-07-01

    Potable water has become a scarce resource in many countries. In fact, the world is not running out of water, but rather, the relatively fixed quantity is becoming too contaminated for many applications. Hence, the present work was designed to evaluate the desalination efficiency of resin and glass fiber-reinforced Polysulfone polymer-based monopolar and bipolar (BPM) ion exchange membranes (with polyvinyl pyrrolidone as the intermediate layer) on a real sample brine solution for 8 h duration. The prepared ion exchange membranes (IEMs) were characterized using FTIR, SEM, TGA, water absorption, and contact angle measurements. The BPM efficiency, electrical conductivity, salinity, sodium, and chloride ion concentration were evaluated for both prepared and commercial-based IEM systems. The current efficiency and energy consumption values obtained during BPMED process were found to be 45 % and 0.41 Wh for RPSu-PVP-based IEM system and 38 % and 1.60 Wh for PSDVB-based IEM system, respectively.

  5. Dynamic behavior of ultra large graphene-based membranes using electrothermal transduction

    Science.gov (United States)

    Al-mashaal, A. K.; Wood, G. S.; Torin, A.; Mastropaolo, E.; Newton, M. J.; Cheung, R.

    2017-12-01

    This letter reports an experimental study of an electrothermal actuator made from an ultra-large graphene-based bilayer thin film with a diameter to thickness aspect ratio of ˜10 000. Suspended thin films consisting of multilayer graphene and 350-500 nm-thick Poly(methyl methacrylate) have been transferred over circular cavities with a diameter of 3.5 mm. The use of bilayer materials with different mechanical and thermal properties results in thin film structures that can be induced to vibrate mechanically under the electrothermal transduction mechanism. The dynamic response of the bilayer has been investigated electrothermally by driving the structures with a combination of alternating current and direct current actuation voltages ( Va c and Vd c) and characterizing their resonant frequencies. It has been found that the bilayer thin film structure behaves as a membrane. In addition, the actuation configurations affect not only the amplitude of vibration but also the tuning of the resonant frequency of the vibrating membranes. The existence of Joule heating-induced tension lowers the mechanical stiffness of the membrane and hence shifts the resonant frequency downwards by -108187 ppm. A resonant frequency of 3.26 kHz with a vibration amplitude of 4.34 nm has been achieved for 350 nm-thick membranes under actuation voltages of 1 V of Va c and 8 V of Vd c.

  6. Schiff bases as cadmium(II) selective ionophores in polymeric membrane electrodes

    International Nuclear Information System (INIS)

    Gupta, V.K.; Singh, A.K.; Gupta, Barkha

    2007-01-01

    The construction and performance characteristics of polymeric membrane electrodes based on two neutral ionophores, N,N'-[bis(pyridin-2-yl)formylidene]butane-1,4-diamine (S 1 ) and N-(2-pyridinylmethylene)-1,2-benzenediamine (S 2 ) for quantification of cadmium ions, are described. The influences of membrane compositions on the potentiometric response of the electrodes have been found to substantially improve the performance characteristics. The best performance was obtained with the electrode having a membrane composition (w/w) of (S 1 ) (2.15%):PVC (32.2%):o-NPOE (64.5%):KTpClPB (1.07%). The proposed electrode exhibits Nernstian response in the concentration range of 7.9 x 10 -8 to 1.0 x 10 -1 M Cd 2+ with limit of detection 5.0 x 10 -8 M, performs satisfactorily over wide pH range (2.0-8.0) with a fast response time (10 s). The sensor has been found to work satisfactorily in partially non-aqueous media up to 30% (v/v) content of methanol, ethanol and acetonitrile and could be used for a period of 2 months. The analytical usefulness of the proposed electrode has been evaluated by its application in the determination of cadmium in real samples. The practical utility of the membrane electrode has also been observed in the presence of surfactants

  7. Schiff bases as cadmium(II) selective ionophores in polymeric membrane electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, V.K. [Department of Chemistry, Indian Institute of Technology-Roorkee, Roorkee 247667 (India)]. E-mail: vinodfcy@iitr.ernet.in; Singh, A.K. [Department of Chemistry, Indian Institute of Technology-Roorkee, Roorkee 247667 (India); Gupta, Barkha [Department of Chemistry, Indian Institute of Technology-Roorkee, Roorkee 247667 (India)

    2007-02-05

    The construction and performance characteristics of polymeric membrane electrodes based on two neutral ionophores, N,N'-[bis(pyridin-2-yl)formylidene]butane-1,4-diamine (S{sub 1}) and N-(2-pyridinylmethylene)-1,2-benzenediamine (S{sub 2}) for quantification of cadmium ions, are described. The influences of membrane compositions on the potentiometric response of the electrodes have been found to substantially improve the performance characteristics. The best performance was obtained with the electrode having a membrane composition (w/w) of (S{sub 1}) (2.15%):PVC (32.2%):o-NPOE (64.5%):KTpClPB (1.07%). The proposed electrode exhibits Nernstian response in the concentration range of 7.9 x 10{sup -8} to 1.0 x 10{sup -1} M Cd{sup 2+} with limit of detection 5.0 x 10{sup -8} M, performs satisfactorily over wide pH range (2.0-8.0) with a fast response time (10 s). The sensor has been found to work satisfactorily in partially non-aqueous media up to 30% (v/v) content of methanol, ethanol and acetonitrile and could be used for a period of 2 months. The analytical usefulness of the proposed electrode has been evaluated by its application in the determination of cadmium in real samples. The practical utility of the membrane electrode has also been observed in the presence of surfactants.

  8. Efficient synthesis of tension modulation in strings and membranes based on energy estimation.

    Science.gov (United States)

    Avanzini, Federico; Marogna, Riccardo; Bank, Balázs

    2012-01-01

    String and membrane vibrations cannot be considered as linear above a certain amplitude due to the variation in string or membrane tension. A relevant special case is when the tension is spatially constant and varies in time only in dependence of the overall string length or membrane surface. The most apparent perceptual effect of this tension modulation phenomenon is the exponential decay of pitch in time. Pitch glides due to tension modulation are an important timbral characteristic of several musical instruments, including the electric guitar and tom-tom drum, and many ethnic instruments. This paper presents a unified formulation to the tension modulation problem for one-dimensional (1-D) (string) and two-dimensional (2-D) (membrane) cases. In addition, it shows that the short-time average of the tension variation, which is responsible for pitch glides, is approximately proportional to the system energy. This proportionality allows the efficient physics-based sound synthesis of pitch glides. The proposed models require only slightly more computational resources than linear models as opposed to earlier tension-modulated models of higher complexity. © 2012 Acoustical Society of America.

  9. High-Tg Polynorbornene-Based Block and Random Copolymers for Butanol Pervaporation Membranes

    Science.gov (United States)

    Register, Richard A.; Kim, Dong-Gyun; Takigawa, Tamami; Kashino, Tomomasa; Burtovyy, Oleksandr; Bell, Andrew

    Vinyl addition polymers of substituted norbornene (NB) monomers possess desirably high glass transition temperatures (Tg); however, until very recently, the lack of an applicable living polymerization chemistry has precluded the synthesis of such polymers with controlled architecture, or copolymers with controlled sequence distribution. We have recently synthesized block and random copolymers of NB monomers bearing hydroxyhexafluoroisopropyl and n-butyl substituents (HFANB and BuNB) via living vinyl addition polymerization with Pd-based catalysts. Both series of polymers were cast into the selective skin layers of thin film composite (TFC) membranes, and these organophilic membranes investigated for the isolation of n-butanol from dilute aqueous solution (model fermentation broth) via pervaporation. The block copolymers show well-defined microphase-separated morphologies, both in bulk and as the selective skin layers on TFC membranes, while the random copolymers are homogeneous. Both block and random vinyl addition copolymers are effective as n-butanol pervaporation membranes, with the block copolymers showing a better flux-selectivity balance. While polyHFANB has much higher permeability and n-butanol selectivity than polyBuNB, incorporating BuNB units into the polymer (in either a block or random sequence) limits the swelling of the polyHFANB and thereby improves the n-butanol pervaporation selectivity.

  10. Tannin-based thin-film composite membranes for solvent nanofiltration

    KAUST Repository

    Perez Manriquez, Liliana

    2017-06-28

    The natural oligomer tannic acid was used as a reactant for an interfacial polymerisation on top of a crosslinked polyacrylonitrile (PAN) membrane. The PAN membrane was soaked with the aqueous tannic acid solution and contacted with a dilute solution of teraphtaloylchloride in hexane. Since both layers, the PAN support and the thin tannin-based layer, are highly crosslinked, the resulting thin film composite membrane is stable in harsh solvent environments such as N-Methyl-2-pyrrolidone (NMP). NMP permeances of up to 0.09L/m2 h bar with a molecular weight cut-off of approximately 800g/mol were obtained. The exceptional stability in NMP and the incorporation of natural compounds like tannic acid for the manufacture of organic solvent nanofiltration membranes provides a cost-effective alternative for industrial separations due to the simplicity of the interfacial reaction and the replacement of the commonly applied toxic aromatic amines. The scale up of the manufacturing process is not difficult; the low price of the natural tannic acid is another advantage.

  11. Fabrication of high-transmission microporous membranes by proton beam writing-based molding technique

    Science.gov (United States)

    Wang, Liping; Meyer, Clemens; Guibert, Edouard; Homsy, Alexandra; Whitlow, Harry J.

    2017-08-01

    Porous membranes are widely used as filters in a broad range of micro and nanofluidic applications, e.g. organelle sorters, permeable cell growth substrates, and plasma filtration. Conventional silicon fabrication approaches are not suitable for microporous membranes due to the low mechanical stability of thin film substrates. Other techniques like ion track etching are limited to the production of randomly distributed and randomly orientated pores with non-uniform pore sizes. In this project, we developed a procedure for fabricating high-transmission microporous membranes by proton beam writing (PBW) with a combination of spin-casting and soft lithography. In this approach, focused 2 MeV protons were used to lithographically write patterns consisting of hexagonal arrays of high-density pillars of few μm size in a SU-8 layer coated on a silicon wafer. After development, the pillars were conformably coated with a thin film of poly-para-xylylene (Parylene)-C release agent and spin-coated with polydimethylsiloxane (PDMS). To facilitate demolding, a special technique based on the use of a laser-cut sealing tape ring was developed. This method facilitated the successful delamination of 20-μm thick PDMS membrane with high-density micropores from the mold without rupture or damage.

  12. STUDY ON HIGH RESOLUTION MEMBRANE-BASED DIFFRACTIVE OPTICAL IMAGING ON GEOSTATIONARY ORBIT

    Directory of Open Access Journals (Sweden)

    J. Jiao

    2017-05-01

    Full Text Available Diffractive optical imaging technology provides a new way to realize high resolution earth observation on geostationary orbit. There are a lot of benefits to use the membrane-based diffractive optical element in ultra-large aperture optical imaging system, including loose tolerance, light weight, easy folding and unfolding, which make it easy to realize high resolution earth observation on geostationary orbit. The implementation of this technology also faces some challenges, including the configuration of the diffractive primary lens, the development of high diffraction efficiency membrane-based diffractive optical elements, and the correction of the chromatic aberration of the diffractive optical elements. Aiming at the configuration of the diffractive primary lens, the “6+1” petal-type unfold scheme is proposed, which consider the compression ratio, the blocking rate and the development complexity. For high diffraction efficiency membrane-based diffractive optical element, a self-collimating method is proposed. The diffraction efficiency is more than 90 % of the theoretical value. For the chromatic aberration correction problem, an optimization method based on schupmann is proposed to make the imaging spectral bandwidth in visible light band reach 100 nm. The above conclusions have reference significance for the development of ultra-large aperture diffractive optical imaging system.

  13. Approach for Self-Calibrating CO2 Measurements with Linear Membrane-Based Gas Sensors

    Directory of Open Access Journals (Sweden)

    Detlef Lazik

    2016-11-01

    Full Text Available Linear membrane-based gas sensors that can be advantageously applied for the measurement of a single gas component in large heterogeneous systems, e.g., for representative determination of CO2 in the subsurface, can be designed depending on the properties of the observation object. A resulting disadvantage is that the permeation-based sensor response depends on operating conditions, the individual site-adapted sensor geometry, the membrane material, and the target gas component. Therefore, calibration is needed, especially of the slope, which could change over several orders of magnitude. A calibration-free approach based on an internal gas standard is developed to overcome the multi-criterial slope dependency. This results in a normalization of sensor response and enables the sensor to assess the significance of measurement. The approach was proofed on the example of CO2 analysis in dry air with tubular PDMS membranes for various CO2 concentrations of an internal standard. Negligible temperature dependency was found within an 18 K range. The transformation behavior of the measurement signal and the influence of concentration variations of the internal standard on the measurement signal were shown. Offsets that were adjusted based on the stated theory for the given measurement conditions and material data from the literature were in agreement with the experimentally determined offsets. A measurement comparison with an NDIR reference sensor shows an unexpectedly low bias (<1% of the non-calibrated sensor response, and comparable statistical uncertainty.

  14. Approach for Self-Calibrating CO₂ Measurements with Linear Membrane-Based Gas Sensors.

    Science.gov (United States)

    Lazik, Detlef; Sood, Pramit

    2016-11-17

    Linear membrane-based gas sensors that can be advantageously applied for the measurement of a single gas component in large heterogeneous systems, e.g., for representative determination of CO₂ in the subsurface, can be designed depending on the properties of the observation object. A resulting disadvantage is that the permeation-based sensor response depends on operating conditions, the individual site-adapted sensor geometry, the membrane material, and the target gas component. Therefore, calibration is needed, especially of the slope, which could change over several orders of magnitude. A calibration-free approach based on an internal gas standard is developed to overcome the multi-criterial slope dependency. This results in a normalization of sensor response and enables the sensor to assess the significance of measurement. The approach was proofed on the example of CO₂ analysis in dry air with tubular PDMS membranes for various CO₂ concentrations of an internal standard. Negligible temperature dependency was found within an 18 K range. The transformation behavior of the measurement signal and the influence of concentration variations of the internal standard on the measurement signal were shown. Offsets that were adjusted based on the stated theory for the given measurement conditions and material data from the literature were in agreement with the experimentally determined offsets. A measurement comparison with an NDIR reference sensor shows an unexpectedly low bias (sensor response, and comparable statistical uncertainty.

  15. Study on High Resolution Membrane-Based Diffractive Optical Imaging on Geostationary Orbit

    Science.gov (United States)

    Jiao, J.; Wang, B.; Wang, C.; Zhang, Y.; Jin, J.; Liu, Z.; Su, Y.; Ruan, N.

    2017-05-01

    Diffractive optical imaging technology provides a new way to realize high resolution earth observation on geostationary orbit. There are a lot of benefits to use the membrane-based diffractive optical element in ultra-large aperture optical imaging system, including loose tolerance, light weight, easy folding and unfolding, which make it easy to realize high resolution earth observation on geostationary orbit. The implementation of this technology also faces some challenges, including the configuration of the diffractive primary lens, the development of high diffraction efficiency membrane-based diffractive optical elements, and the correction of the chromatic aberration of the diffractive optical elements. Aiming at the configuration of the diffractive primary lens, the "6+1" petal-type unfold scheme is proposed, which consider the compression ratio, the blocking rate and the development complexity. For high diffraction efficiency membrane-based diffractive optical element, a self-collimating method is proposed. The diffraction efficiency is more than 90 % of the theoretical value. For the chromatic aberration correction problem, an optimization method based on schupmann is proposed to make the imaging spectral bandwidth in visible light band reach 100 nm. The above conclusions have reference significance for the development of ultra-large aperture diffractive optical imaging system.

  16. Glucose oxidase as a biocatalytic enzyme-based bio-fuel cell using Nafion membrane limiting crossover

    International Nuclear Information System (INIS)

    Naidoo, S; Blottnitz, H; Naidoo, Q; Vaivars, G

    2013-01-01

    A novel combination for an Enzyme-based Biofuel cell included a Nafion membrane as an ion transporter that maintained a working cell charge and inhibited membrane degradation. The prototype cell chamber used oxygen (O 2 ) in the cathode cell and glucose in the anode. The Nafion membrane stability studied here was evidently in the region of 0% loss of conductivity as the charge was constant and increased after the addition of glucose. The prototype cell chamber used NaCl in the cathode cell and glucose oxidase (GOx) in the anodic chamber was successfully studied for membrane stability showed in this study no evidence of poisoning from membrane leakage in a controlled pH environment. There was no crossover at the anaerobic operating ambient temperatures and under physiological pH 5 – 7 conditions. In this research we have successfully used a Nafion membrane together with GOx and under controlled conditions produced respectable power densities

  17. A fluorogenic probe for SNAP-tagged plasma membrane proteins based on the solvatochromic molecule Nile Red.

    Science.gov (United States)

    Prifti, Efthymia; Reymond, Luc; Umebayashi, Miwa; Hovius, Ruud; Riezman, Howard; Johnsson, Kai

    2014-03-21

    A fluorogenic probe for plasma membrane proteins based on the dye Nile Red and SNAP-tag is introduced. It takes advantage of Nile Red, a solvatochromic molecule highly fluorescent in an apolar environment, such as cellular membranes, but almost dark in a polar aqueous environment. The probe possesses a tuned affinity for membranes allowing its Nile Red moiety to insert into the lipid bilayer of the plasma membrane, becoming fluorescent, only after its conjugation to a SNAP-tagged plasma membrane protein. The fluorogenic character of the probe was demonstrated for different SNAP-tag fusion proteins, including the human insulin receptor. This work introduces a new approach for generating a powerful turn-on probe for "no-wash" labeling of plasma membrane proteins with numerous applications in bioimaging.

  18. Membrane-based assay for iodide ions based on anti-leaching of gold nanoparticles.

    Science.gov (United States)

    Shen, Yu-Wei; Hsu, Pang-Hung; Unnikrishnan, Binesh; Li, Yu-Jia; Huang, Chih-Ching

    2014-02-26

    We report a label-free colorimetric strategy for the highly selective and sensitive detection of iodide (I(-)) ions in human urine sample, seawater and edible salt. A poly(N-vinyl-2-pyrrolidone)-stabilized Au nanoparticle (34.2-nm) was prepared to detect I(-) ions using silver (Ag(+)) and cyanide (CN(-)) ions as leaching agents in a glycine-NaOH (pH 9.0) solution. For the visual detection of the I(-) ions by naked eye, and for long time stability of the probe, Au nanoparticles (NPs) decorated mixed cellulose ester membrane (MCEM) was prepared (Au NPs/MCEM). The Au NPs-based probe (CN(-)/Ag(+)-Au NPs/MCEM) operates on the principle that Ag(+) ions form a monolyar silver atoms/ions by aurophilic/argentophilic interactions on the Au NPs and it accelerates the leaching rate of Au atoms in presence of CN(-) ions. However, when I(-) is introduced into this system, it inhibits the leaching of Au atoms because of the strong interactions between Ag/Au ions and I(-) ions. Inductively coupled plasma mass spectrometry, surface-assisted laser desorption/ionization time-of-flight mass spectrometry were used to characterize the surface properties of the Au NPs in the presence of Ag(+) and I(-). Under optimal solution conditions, the CN(-)/Ag(+)-Au NPs/MCEM probe enabled the detection of I(-) by the naked eye at nanomolar concentrations with high selectivity (at least 1000-fold over other anions). In addition, this cost-effective probe allowed the determination of I(-) ions in complex samples, such as urine, seawater, and edible salt samples.

  19. Lithography-based fabrication of nanopore arrays in freestanding SiN and graphene membranes

    Science.gov (United States)

    Verschueren, Daniel V.; Yang, Wayne; Dekker, Cees

    2018-04-01

    We report a simple and scalable technique for the fabrication of nanopore arrays on freestanding SiN and graphene membranes based on electron-beam lithography and reactive ion etching. By controlling the dose of the single-shot electron-beam exposure, circular nanopores of any size down to 16 nm in diameter can be fabricated in both materials at high accuracy and precision. We demonstrate the sensing capabilities of these nanopores by translocating dsDNA through pores fabricated using this method, and find signal-to-noise characteristics on par with transmission-electron-microscope-drilled nanopores. This versatile lithography-based approach allows for the high-throughput manufacturing of nanopores and can in principle be used on any substrate, in particular membranes made out of transferable two-dimensional materials.

  20. Modeling and Simulation of Membrane-Based Dehumidification and Energy Recovery Process

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Zhiming [ORNL; Abdelaziz, Omar [ORNL; Qu, Ming [ORNL

    2017-01-01

    This paper introduces a first-order physics-based model that accounts for the fundamental heat and mass transfer between a humid-air vapor stream on feed side to another flow stream on permeate side. The model comprises a few optional submodels for membrane mass transport; and it adopts a segment-by-segment method for discretizing heat and mass transfer governing equations for flow streams on feed and permeate sides. The model is able to simulate both dehumidifiers and energy recovery ventilators in parallel-flow, cross-flow, and counter-flow configurations. The predicted tresults are compared reasonably well with the measurements. The open-source codes are written in C++. The model and open-source codes are expected to become a fundament tool for the analysis of membrane-based dehumidification in the future.

  1. Nitrocellulose membrane-based enzyme-linked immunoassay for dengue serotype-1 IgM detection

    International Nuclear Information System (INIS)

    Leon, S.; Guevara, C.; Chunga, A.

    1999-01-01

    To evaluate the sensitivity and specifity of a nitrocellulose membrane-based immunoassay for dengue IgM, with respect to capture enzyme immunoassay, for the diagnosis of dengue virus infection. 101 serum samples were processed and divided into 2 groups: 53 from dengue serotype 1 (DEN1) infected patients, and 48 from healthy subjects. Both groups were tested with a nitrocellulose membrane-based IgM capture enzyme immunoassay (NMB-EIA) and also with an ELISA as referential pattern. NMB-EIA testing detected IgM anti-DEN1 in 94,34% of samples from infected patients, and in 14,58% of control samples, whereas ELISA fails to report false positive or false negative results: NMB-EIA appears to be a good alternative for dengue infection diagnosis. (authors)

  2. The humidifier disinfectant case and the legislative challenges of the 20th Congress

    Directory of Open Access Journals (Sweden)

    Taehyun Park

    2016-08-01

    Full Text Available A number of absurdities surrounding the humidifier disinfectant (HD incident may have occurred because 1 a judicial system operates on the underlying false assumption that the involved parties are equals in knowledge, information and resource mobilization capabilities, regardless of respective real status as company or individual; 2 there is a lack of a system that mandates a company to prevent and actively manage possible catastrophes; 3 the regulatory scheme makes companies believe that as long as they are complying with the existing regulations, they have satisfied all of their responsibilities. I believe that this issue is an opportunity to bring about changes in the judicial redress system, the system of internal management of manufacturers, and the regulatory system of the government. The following regulation amendments are needed to move towards the changes stated above. First, legislation relating to victim relief that is applicable to the HD incident must be established. Second, a risk management system must be formed within the manufacturing company and to this end an institutional environment for the system must be established within regulatory framework. Furthermore, legislation must be passed that could punish companies themselves that have caused severe damage to individuals because they had failed to take necessary actions to avoid foreseeable harm. Finally, the framework of regulation must be changed so that the company, who has the necessary information regarding the product and the component chemicals used in the product, must self-directed experiment and assessment of the safety of their own products.

  3. (Ce,Gd)O2−δ-based dual phase membranes for oxygen separation

    DEFF Research Database (Denmark)

    Samson, Alfred Junio; Søgaard, Martin; Hendriksen, Peter Vang

    2014-01-01

    and characterized with respect to sinterability, oxygen permeation rate, phase interaction, and microstructure. These factors are important when considering the development of composite membranes with CGO as the oxide ion conducting phase. Composite membranes with relative densities >91% were fabricated using....... The results indicate a promising prospect for further tailoring and optimization of CGO-based composites for application in oxygen separation....

  4. Tailoring Escherichia coli for the L-rhamnose PBAD promoter-based production of membrane and secretory proteins

    NARCIS (Netherlands)

    Hjelm, Anna; Karyolaimos, Alexandros; Zhang, Zhe; Rujas, Edurne; Vikström, David; Slotboom, Dirk Jan; de Gier, Jan-Willem

    Membrane and secretory protein production in Escherichia coli requires precisely controlled production rates to avoid the deleterious saturation of their biogenesis pathways. Based on this requirement, the E. coli L-rhamnose PBAD promoter (PrhaBAD) is often used for membrane and secretory protein

  5. Poly-electrolyte fuel cell membrane based on crosslinked polytetrafluoroethylene by radiation-grafting

    International Nuclear Information System (INIS)

    Ichizuri, Shogo; Asano, Saneto; Li, Jingye

    2004-01-01

    Poly-electrolyte fuel cell (PEFC) membranes based on crosslinked Polytetrafluoroethylene (RX-PTFE) have been fabricated by radiation-grafting with reactive styrene monomers using γ-ray irradiation in air at room temperature / electron beam irradiation under N 2 gas atmosphere at room temperature. The characteristic properties of obtained materials have been measured by DSC, TGA and FT-IR spectroscopy, and so on. Ion exchange capacity of sulfonated crosslinked PTFE has been achieved 2.8meq/g. (author)

  6. 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...

  7. Functionalization of mesoporous silica membrane with a Schiff base fluorophore for Cu(II) ion sensing

    Energy Technology Data Exchange (ETDEWEB)

    Chen Xiaotong [Department of Chemistry, Graduate School of Science, Tohoku University, Aoba-ku 980-8578, Sendai, Miyagi Prefecture (Japan); Department of Chemistry, Tsinghua University, Beijing 100084 (China); Yamaguchi, Akira [College of Science, Ibaraki University, Bunkyo 2-1-1, Mito, Ibaraki 310-8512 (Japan); Frontier Research Center for Applied Atomic Sciences, Ibaraki University, Tokai, Ibaraki 319-1106 (Japan); Namekawa, Manato [Department of Chemistry, Graduate School of Science, Tohoku University, Aoba-ku 980-8578, Sendai, Miyagi Prefecture (Japan); Kamijo, Toshio [Department of Chemistry, Graduate School of Science, Tohoku University, Aoba-ku 980-8578, Sendai, Miyagi Prefecture (Japan); Tsuruoka National College of Technology, Aza-Sawada, Tsuruoka 997-8511 (Japan); Teramae, Norio, E-mail: teramae@m.tohoku.ac.jp [Department of Chemistry, Graduate School of Science, Tohoku University, Aoba-ku 980-8578, Sendai, Miyagi Prefecture (Japan); Tong, Aijun, E-mail: tongaj@mail.tsinghua.edu.cn [Department of Chemistry, Tsinghua University, Beijing 100084 (China)

    2011-06-24

    Graphical abstract: Highlights: > A hybrid mesoporous membrane (SB-HMM) functionalized by Schiff base fluorophores was fabricated. > SB-HMM showed strong fluorescence with aggregation-induced emission enhancement properties. > SB-HMM was applicable for the detection of Cu(II) in an aqueous solution with good reversibility and reproducibility. - Abstract: A Schiff base (SB) immobilized hybrid mesoporous silica membrane (SB-HMM) was prepared by immobilizing a Schiff base onto the pore surface of mesoporous silica (pore size = 3.1 nm) embedded in the pores of a porous anodic alumina membrane. In contrast to the non-fluorescent analogous SB molecule in homogeneous solutions, SB-HMM exhibited intense fluorescence due to emission enhancement caused by aggregation of SB groups on the pore surface. The high quantum efficiency of the surface SB groups allows SB-HMM to function as a fluorescent sensor for Cu(II) ions in an aqueous solution with good sensitivity, selectivity and reproducibility. Under the optimal conditions described, the linear ranges of fluorescence intensity for Cu(II) are 1.2-13.8 (M (R{sup 2} = 0.993) and 19.4-60 (R{sup 2} = 0.992) (M. The limit of detection for Cu(II) is 0.8 {mu}M on basis of the definition by IUPAC (C{sub LOD} = 3.3S{sub b}/m).

  8. 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.

  9. Energy Demand Comparison between Hollow Fiber Membrane Based Dehumidification and Evaporative Cooling Dehumidification Using TRNSYS

    Directory of Open Access Journals (Sweden)

    Jeachul Jang

    2018-05-01

    Full Text Available This communication presents the performance evaluation and comparative study between two different techniques: a membrane-based dehumidification system (MDS and evaporative cooling dehumidification (ECD for a typical climate of South Korea. Although there are different ways to dehumidify the air in living and work spaces, the membrane-based dehumidification system (MDS is the most effective way as it neither causes a change in the temperature nor harms the environment. Moreover, it consumes significantly less energy when compared to other methods. There are also limitations concerning products that are sensitive to temperature such as food and pharmaceutical products; the method of evaporative cooling dehumidification is not suitable for such applications. The present work demonstrated the excellent energy-saving performance of the membrane-based dehumidification system against evaporative cooling dehumidification by comparing the performance of these two systems during the rainy season using a transient system simulation. The results showed that the MDS helped to reduce the dehumidification load by more than 47.6% when compared to the ECD system, which is a significant achievement in this regard.

  10. Theoretical Analysis on Mechanical Deformation of Membrane-Based Photomask Blanks

    Science.gov (United States)

    Marumoto, Kenji; Aya, Sunao; Yabe, Hedeki; Okada, Tatsunori; Sumitani, Hiroaki

    2012-04-01

    Membrane-based photomask is used in proximity X-ray lithography including that in LIGA (Lithographie, Galvanoformung und Abformung) process, and near-field photolithography. In this article, out-of-plane deformation (OPD) and in-plane displacement (IPD) of membrane-based photomask blanks are theoretically analyzed to obtain the mask blanks with flat front surface and low stress absorber film. First, we derived the equations of OPD and IPD for the processing steps of membrane-based photomask such as film deposition, back-etching and bonding, using a theory of symmetrical bending of circular plates with a coaxial circular hole and that of deformation of cylinder under hydrostatic pressure. The validity of the equations was proved by comparing the calculation results with experimental ones. Using these equations, we investigated the relation between the geometry of the mask blanks and the distortions generally, and gave the criterion to attain the flat front surface. Moreover, the absorber stress-bias required to obtain zero-stress on finished mask blanks was also calculated and it has been found that only little stress-bias was required for adequate hole size of support plate.

  11. A durable alternative for proton-exchange membranes: sulfonated poly(benzoxazole thioether sulfone)s

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Dan [Center for Innovative Fuel Cell and Battery Technologies, School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0245 (United States); Lab of PEMFC Key Materials and Technologies, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Liaoning, Dalian 116023 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100039 (China); Li, Jinhuan [Center for Innovative Fuel Cell and Battery Technologies, School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0245 (United States); College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Song, Min-Kyu; Liu, Meilin [Center for Innovative Fuel Cell and Battery Technologies, School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0245 (United States); Yi, Baolian; Zhang, Huamin [Lab of PEMFC Key Materials and Technologies, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Liaoning, Dalian 116023 (China)

    2011-03-18

    To develop a durable proton-exchange membrane (PEM) for fuel-cell applications, a series of sulfonated poly(benzoxazole thioether sulfone)s (SPTESBOs) are designed and synthesized, with anticipated good dimensional stability (via acid-base cross linking), improved oxidative stability against free radicals (via incorporation of thioether groups), and enhanced inherent stability (via elimination of unstable end groups) of the backbone. The structures and the degree of sulfonation of the copolymers are characterized using Fourier-transform infrared spectroscopy, and nuclear magnetic resonance spectroscopy ({sup 1}H NMR and {sup 19}F NMR). The electrochemical stabilities of the monomers are examined using cyclic voltammetry in a typical three-electrode cell configuration. The physicochemical properties of the membranes vital to fuel-cell performance are also carefully evaluated under conditions relevant to fuel-cell operation, including chemical and thermal stability, proton conductivity, solubility in different solvents, water uptake, and swelling ratio. The new membranes exhibit low dimensional change at 25 C to 90 C and excellent thermal stability up to 250 C. Upon elimination of unstable end groups, the co-polymers display enhanced chemical resistance and oxidative stability in Fenton's test. Further, the SPTESBO-HFB-60 (HFB-60=hexafluorobenzene, 60 mol% sulfone) membrane displays comparable fuel-cell performance to that of an NRE 212 membrane at 80 C under fully humidified condition, suggesting that the new membranes have the potential to be more durable but less expensive for fuel-cell applications. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  12. Pentiptycene-based polyurethane with enhanced mechanical properties and CO2-plasticization resistance for thin film gas separation membranes.

    Science.gov (United States)

    Pournaghshband Isfahani, Ali; Sadeghi, Morteza; Wakimoto, Kazuki; Shrestha, Binod Babu; Bagheri, Rouhollah; Sivaniah, Easan; Ghalei, Behnam

    2018-04-30

    Development of thin film composite (TFC) membranes offers an opportunity to achieve the permeability/selectivity requirements for optimum CO2 separation performance. However, the durability and performance of thin film gas separation membranes are mostly challenged by weak mechanical properties and high CO2 plasticization. Here, we designed new polyurethane (PU) structures with bulky aromatic chain extenders that afford preferred mechanical properties for ultra-thin film formation. An improvement of about 1500% in Young's modulus and 600% in hardness was observed for pentiptycene-based PUs compared to typical PU membranes. Single (CO2, H2, CH4, and N2) and mixed (CO2/N2 and CO2/CH4) gas permeability tests were performed on the PU membranes. The resulting TFC membranes showed a high CO2 permeance up to 1400 GPU (10-6 cm3(STP) cm-2s-1 cmHg-1) and the CO2/N2 and CO2/H2 selectivities of about 22 and 2.1, respectively. The enhanced mechanical properties of pentiptycene-based PUs results in high performance thin membranes with the similar selectivity of the bulk polymer. The thin film membranes prepared from pentiptycene-based PUs also showed a two-fold enhanced plasticization resistance compared to non-pentiptycene containing PU membranes.

  13. Process for production of electrical energy from the neutralization of acid and base in a bipolar membrane cell

    International Nuclear Information System (INIS)

    Walther, J.F.

    1982-01-01

    Electrical energy is generated from acid-base neutralization reactions in electrodialytic cells. Permselective bipolar membranes in these cells are contacted on their cation selective faces by aqueous acid streams and on their anion-selective faces by aqueous base streams. Spontaneous neutralization reactions between the basic anions and acidic cations through the bipolar membranes produce electrical potential differences between the acid and base streams. These potential differences are transmitted to electrodes to produce electrical energy which is withdrawn from the cell

  14. Voltage-Gated Transport of Nanoparticles across Free-Standing All-Carbon-Nanotube-Based Hollow-Fiber Membranes.

    Science.gov (United States)

    Wei, Gaoliang; Quan, Xie; Chen, Shuo; Fan, Xinfei; Yu, Hongtao; Zhao, Huimin

    2015-07-15

    Understanding the mechanism underlying controllable transmembrane transport observed in biological membranes benefits the development of next-generation separation membranes for a variety of important applications. In this work, on the basis of common structural features of cell membranes, a very simple biomimetic membrane system exhibiting gated transmembrane performance has been constructed using all-carbon-nanotube (CNT)-based hollow-fiber membranes. The conductive CNT membranes with hydrophobic pore channels can be positively or negatively charged and are consequently capable of regulating the transport of nanoparticles across their pore channels by their "opening" or "closing". The switch between penetration and rejection of nanoparticles through/by CNT membranes is of high efficiency and especially allows dynamic control. The underlying mechanism is that CNT pore channels with different polarities can prompt or prevent the formation of their noncovalent interactions with charged nanoparticles, resulting in their rejection or penetration by/through the CNT membranes. The theory about noncovalent interactions and charged pore channels may provide new insight into understanding the complicated ionically and bimolecularly gated transport across cell membranes and can contribute to many other important applications beyond the water purification and resource recovery demonstrated in this study.

  15. Development and use of thin film composite based positively charged nanofiltration membranes in separation of aqueous streams and nuclear effluents

    International Nuclear Information System (INIS)

    Dey, T.K.; Bindal, R.C.; Prabhakar, S.; Tewari, P.K.

    2010-01-01

    A new, positively charged, thin film composite (TFC) type nanofiltration membrane has been developed and studied for its use in various aqueous stream separations. The membrane, containing fixed quaternary ammonium moieties, was developed by insitu interfacial polymerization of a functionalized amine (polyethyleneimine) and terephthaloyl chloride on a suitable base membrane. The nature of the charge on the membrane was established by ATR FT IR spectroscopy and was estimated by determination of its ion exchange capacity. The membrane was tested for its performance in single solute feed systems containing salts of various combinations of univalent and bivalent ions (NaCl, Na 2 SO 4 , CaCl 2 and MgSO 4 ) in test cell as well as in 2512 spiral modules. The membrane gave differential separation profile for these solutes with high rejection for CaCl 2 and low rejection for Na 2 SO 4 due to positive charge on the membrane and the type of charge constituting the salts. The membrane was also used for separation of simulated effluent solution containing uranyl nitrate in combination with ammonium nitrate which is a common effluent generated in nuclear industry. Here also the membrane gave differential separation profile for uranyl nitrate and ammonium nitrate in their mixture by concentrating the former salt and passing the later. This helped separation of these two solutes in the mixture into two different streams. (author)

  16. Enriched glucose and dextrin mannitol-based media modulates fibroblast behavior on bacterial cellulose membranes

    International Nuclear Information System (INIS)

    Stumpf, Taisa R.; Pértile, Renata A.N.; Rambo, Carlos R.; Porto, Luismar M.

    2013-01-01

    Bacterial cellulose (BC) produced by Gluconacetobacter hansenii is a suitable biopolymer for biomedical applications. In order to modulate the properties of BC and expand its use as substrate for tissue engineering mainly in the form of biomembranes, glucose or dextrin were added into a BC fermentation mannitol-based medium (BCGl and BCDe, respectively) under static culture conditions. SEM images showed effects on fiber density and porosity on both sides of the BC membranes. Both enriched media decreased the BET surface area, water holding capacity, and rehydration rate. Fourier transform infrared (attenuated total reflectance mode) spectroscopy (FTIR-ATR) analysis revealed no change in the chemical structure of BC. L929 fibroblast cells were seeded on all BC-based membranes and evaluated in aspects of cell adhesion, proliferation and morphology. BCG1 membranes showed the highest biological performance and hold promise for the use in tissue engineering applications. - Highlights: • Glucose and dextrin were used to modify culture media for BC production. • Microarchitecture of BC was different depending on the enriching agent. • Fibroblasts adhered on the surface of BC modified microarchitectures. • Fibroblasts adhered on glucose modified BC exhibited healthy cell morphology

  17. Fabrication and Characterization of Magnetoresponsive Electrospun Nanocomposite Membranes Based on Methacrylic Random Copolymers and Magnetite Nanoparticles

    Directory of Open Access Journals (Sweden)

    Ioanna Savva

    2012-01-01

    Full Text Available Magnetoresponsive polymer-based fibrous nanocomposites belonging to the broad category of stimuli-responsive materials, is a relatively new class of “soft” composite materials, consisting of magnetic nanoparticles embedded within a polymeric fibrous matrix. The presence of an externally applied magnetic field influences the properties of these materials rendering them useful in numerous technological and biomedical applications including sensing, magnetic separation, catalysis and magnetic drug delivery. This study deals with the fabrication and characterization of magnetoresponsive nanocomposite fibrous membranes consisting of methacrylic random copolymers based on methyl methacrylate (MMA and 2-(acetoacetoxyethyl methacrylate (AEMA (MMA-co-AEMA and oleic acid-coated magnetite (OA·Fe3O4 nanoparticles. The AEMA moieties containing β-ketoester side-chain functionalities were introduced for the first time in this type of materials, because of their inherent ability to bind effectively onto inorganic surfaces providing an improved stabilization. For membrane fabrication the electrospinning technique was employed and a series of nanocomposite membranes was prepared in which the polymer content was kept constant and only the inorganic (OA·Fe3O4 content varied. Further to the characterization of these materials in regards to their morphology, composition and thermal properties, assessment of their magnetic characteristics disclosed tunable superparamagnetic behaviour at ambient temperature.

  18. Analysis of direct contact membrane distillation based on a lumped-parameter dynamic predictive model

    KAUST Repository

    Karam, Ayman M.

    2016-10-03

    Membrane distillation (MD) is an emerging technology that has a great potential for sustainable water desalination. In order to pave the way for successful commercialization of MD-based water desalination techniques, adequate and accurate dynamical models of the process are essential. This paper presents the predictive capabilities of a lumped-parameter dynamic model for direct contact membrane distillation (DCMD) and discusses the results under wide range of steady-state and dynamic conditions. Unlike previous studies, the proposed model captures the time response of the spacial temperature distribution along the flow direction. It also directly solves for the local temperatures at the membrane interfaces, which allows to accurately model and calculate local flux values along with other intrinsic variables of great influence on the process, like the temperature polarization coefficient (TPC). The proposed model is based on energy and mass conservation principles and analogy between thermal and electrical systems. Experimental data was collected to validated the steady-state and dynamic responses of the model. The obtained results shows great agreement with the experimental data. The paper discusses the results of several simulations under various conditions to optimize the DCMD process efficiency and analyze its response. This demonstrates some potential applications of the proposed model to carry out scale up and design studies. © 2016

  19. Analysis of direct contact membrane distillation based on a lumped-parameter dynamic predictive model

    KAUST Repository

    Karam, Ayman M.; Alsaadi, Ahmad Salem; Ghaffour, NorEddine; Laleg-Kirati, Taous-Meriem

    2016-01-01

    Membrane distillation (MD) is an emerging technology that has a great potential for sustainable water desalination. In order to pave the way for successful commercialization of MD-based water desalination techniques, adequate and accurate dynamical models of the process are essential. This paper presents the predictive capabilities of a lumped-parameter dynamic model for direct contact membrane distillation (DCMD) and discusses the results under wide range of steady-state and dynamic conditions. Unlike previous studies, the proposed model captures the time response of the spacial temperature distribution along the flow direction. It also directly solves for the local temperatures at the membrane interfaces, which allows to accurately model and calculate local flux values along with other intrinsic variables of great influence on the process, like the temperature polarization coefficient (TPC). The proposed model is based on energy and mass conservation principles and analogy between thermal and electrical systems. Experimental data was collected to validated the steady-state and dynamic responses of the model. The obtained results shows great agreement with the experimental data. The paper discusses the results of several simulations under various conditions to optimize the DCMD process efficiency and analyze its response. This demonstrates some potential applications of the proposed model to carry out scale up and design studies. © 2016

  20. Polyethersulfone-based ultrafiltration hollow fibre membrane for drinking water treatment systems

    Science.gov (United States)

    Chew, Chun Ming; Ng, K. M. David; Ooi, H. H. Richard

    2017-12-01

    Conventional media/sand filtration has been the mainstream water treatment process for most municipal water treatment plants in Malaysia. Filtrate qualities of conventional media/sand filtration are very much dependent on the coagulation-flocculation process prior to filtration and might be as high as 5 NTU. However, the demands for better quality of drinking water through public piped-water supply systems are growing. Polymeric ultrafiltration (UF) hollow fibre membrane made from modified polyethersulfone (PES) material is highly hydrophilic with high tensile strength and produces excellent quality filtrate of below 0.3 NTU in turbidity. This advanced membrane filtration material is also chemical resistance which allows a typical lifespan of 5 years. Comparisons between the conventional media/sand filtration and PES-based UF systems are carried out in this paper. UF has been considered as the emerging technology in municipal drinking water treatment plants due to its consistency in producing high quality filtrates even without the coagulation-flocculation process. The decreasing cost of PES-based membrane due to mass production and competitive pricing by manufacturers has made the UF technology affordable for industrial-scale water treatment plants.

  1. Enriched glucose and dextrin mannitol-based media modulates fibroblast behavior on bacterial cellulose membranes

    Energy Technology Data Exchange (ETDEWEB)

    Stumpf, Taisa R.; Pértile, Renata A.N. [Integrated Technologies Laboratory, Department of Chemical and Food Engineering (Brazil); Rambo, Carlos R., E-mail: rambo@intelab.ufsc.br [Department of Electrical Engineering, Federal University of Santa Catarina, Florianópolis 88040-900 (Brazil); Porto, Luismar M. [Integrated Technologies Laboratory, Department of Chemical and Food Engineering (Brazil)

    2013-12-01

    Bacterial cellulose (BC) produced by Gluconacetobacter hansenii is a suitable biopolymer for biomedical applications. In order to modulate the properties of BC and expand its use as substrate for tissue engineering mainly in the form of biomembranes, glucose or dextrin were added into a BC fermentation mannitol-based medium (BCGl and BCDe, respectively) under static culture conditions. SEM images showed effects on fiber density and porosity on both sides of the BC membranes. Both enriched media decreased the BET surface area, water holding capacity, and rehydration rate. Fourier transform infrared (attenuated total reflectance mode) spectroscopy (FTIR-ATR) analysis revealed no change in the chemical structure of BC. L929 fibroblast cells were seeded on all BC-based membranes and evaluated in aspects of cell adhesion, proliferation and morphology. BCG1 membranes showed the highest biological performance and hold promise for the use in tissue engineering applications. - Highlights: • Glucose and dextrin were used to modify culture media for BC production. • Microarchitecture of BC was different depending on the enriching agent. • Fibroblasts adhered on the surface of BC modified microarchitectures. • Fibroblasts adhered on glucose modified BC exhibited healthy cell morphology.

  2. Fiber Temperature Sensor Based on Micro-mechanical Membranes and Optical Interference Structure

    International Nuclear Information System (INIS)

    Liu Yueming; Tian Weijian; Hua Jing

    2011-01-01

    A novel fiber temperature sensor is presented theoretically and experimentally in this paper. Its working principle is based on Optical Fabry-Perot interference structure that is formed between a polished optical fiber end and micro-mechanical Bi-layered membranes. When ambient temperature is varying, Bi-layered membranes will be deflected and the length of Fabry-Perot cavity will be changed correspondingly. By detecting the reflecting optical intensity from the Fabry-Perot cavity, the ambient temperature can be measured. Using finite element software ANSYS, the sensor structure was optimized based on optical Interference theory and Bi-layered membranes thermal expansion theory, and theoretical characteristics was simulated by computer software. In the end, using optical fiber 2x2 coupler and photo-electrical detector, the fabricated sample sensor was tested successfully by experiment that demonstrating above theoretical analysis and simulation results. This sensor has some favorable features, such as: micro size owing to its micro-mechanical structure, high sensitivity owing to its working Fabry-Perot interference cavity structure, and optical integration character by using optical fiber techniques.

  3. Multifunctional membranes based on spinning technologies: the synergy of nanofibers and nanoparticles

    International Nuclear Information System (INIS)

    Roso, Martina; Modesti, Michele; Sundarrajan, Subramanian; Pliszka, Damian; Ramakrishna, Seeram

    2008-01-01

    A multicomponent membrane based on polysulfone nanofibers and titanium dioxide nanoparticles is produced by the coupling of electrospinning and electrospraying techniques. The manufactured product can satisfy a number of conflicting requirements begetting its technical and functional versatility as well as the reliability of the process. As nanoparticle dispersion is a critical issue in nanoparticle technology, their distribution and morphology have been extensively studied before and after electrospraying, and process optimization has been carried out to obtain nanoparticles uniformly spread over electrospun nanofibers. These membranes have been proved to be a good candidate for supported catalysis due to the photocatalytic activity of TiO 2 , tested for degradation of CEPS, a mustard agent simulant. At the same time, an effective improvement in filtering properties in terms of pressure drop has also been studied

  4. Adhesive coatings based on melanin-like nanoparticles for surgical membranes.

    Science.gov (United States)

    Scognamiglio, Francesca; Travan, Andrea; Turco, Gianluca; Borgogna, Massimiliano; Marsich, Eleonora; Pasqua, Mattia; Paoletti, Sergio; Donati, Ivan

    2017-07-01

    Adhesive coatings for implantable biomaterials can be designed to prevent material displacement from the site of implant. In this paper, a strategy based on the use of melanin-like nanoparticles (MNPs) for the development of adhesive coatings for polysaccharidic membranes was devised. MNPs were synthesized in vitro and characterized in terms of dimensions and surface potential, as a function of pH and ionic strength. The in vitro biocompatibility of MNPs was investigated on fibroblast cells, while the antimicrobial properties of MNPs in suspension were evaluated on E. coli and S. aureus cultures. The manufacturing of the adhesive coatings was carried out by spreading MNPs over the surface of polysaccharidic membranes; the adhesive properties of the nano-engineered coating to the target tissue (intestinal serosa) were studied in simulated physiological conditions. Overall, this study opens for novel approaches in the design of naturally inspired nanostructured adhesive systems. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. A thermodynamic perspective to study energy performance of vacuum-based membrane dehumidification

    KAUST Repository

    Bui, Thuan Duc

    2017-05-13

    In humid environments, decoupling the latent and sensible cooling loads - dehumidifying - can significantly improve chiller efficiency. Here, a basic limit for dehumidification efficiency is established from fundamental thermodynamics. This is followed by the derivation of how this limit is modified when the pragmatic constraint of a finite flux must be accommodated. These limits allow one to identify promising system modifications, and to quantify their impact. The focus is on vacuum-based membrane dehumidification. New high-efficiency configurations are formulated, most notably, by coupling pumping with condensation. More than an order-of-magnitude improvement in efficiency is achievable. It is contingent on water vapor exiting at its saturation pressure rather than at ambient pressure. Sensitivity studies to recovery ratio, temperature, relative humidity and membrane selectivity are also presented.

  6. A novel pH optical sensor using methyl orange based on triacetylcellulose membranes as support.

    Science.gov (United States)

    Hosseini, Mohammad; Heydari, Rouhollah; Alimoradi, Mohammad

    2014-07-15

    A novel pH optical sensor based on triacetylcellulose membrane as solid support was developed by using immobilization of methyl orange indicator. The prepared optical sensor was fixed into a flow cell for on-line pH monitoring. Variables affecting sensor performance, such as pH of dye bonding to triacetylcellulose membrane and dye concentration have been fully evaluated and optimized. The calibration curve showed good behavior and precision (RSDpH range of 4.0-12.0. No significant variation was observed on sensor response with increasing the ionic strength in the range of 0.0-0.5M of sodium chloride. Determination of pH by using the proposed optical sensor is on-line, quick, inexpensive, selective and sensitive in the pH range of 4.0-12.0. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. PVC membrane based potentiometric sensor for uranyl ion using thenoyl trifluoro acetone as ionophore

    International Nuclear Information System (INIS)

    Nanda, D.; Chouhan, H.P.S.; Maiti, B.

    2004-01-01

    Uranyl ion selective electrode based on thenoyl trifluoro acetone (TTA) incorporated into a polyvinyl chloride (PVC) membrane has been developed where dibutyl phthalate and sodium tetraphenyl borate have been used as plasticizer and anion excluder respectively. The PVC membrane containing the active ionophore, TTA, and the other ingredients has been directly cast a graphite electrode. The electrode shows near Nernstian response to UO 2 2+ in the concentration range of 10 -1 to 10 -6 mol. L -1 an average slope of 30 mV/decade. Alkali and alkaline earth ions do not interfere with the determination of uranyl ion. Interference of transition metal ions and Th (IV) is eliminated using EDTA. (author)

  8. Nonlinear Lyapunov-based boundary control of distributed heat transfer mechanisms in membrane distillation plant

    KAUST Repository

    Eleiwi, Fadi

    2015-07-01

    This paper presents a nonlinear Lyapunov-based boundary control for the temperature difference of a membrane distillation boundary layers. The heat transfer mechanisms inside the process are modeled with a 2D advection-diffusion equation. The model is semi-descretized in space, and a nonlinear state-space representation is provided. The control is designed to force the temperature difference along the membrane sides to track a desired reference asymptotically, and hence a desired flux would be generated. Certain constraints are put on the control law inputs to be within an economic range of energy supplies. The effect of the controller gain is discussed. Simulations with real process parameters for the model, and the controller are provided. © 2015 American Automatic Control Council.

  9. Green Materials Science and Engineering Reduces Biofouling: Approaches for Medical and Membrane-based Technologies

    Directory of Open Access Journals (Sweden)

    Kerianne M Dobosz

    2015-03-01

    Full Text Available Numerous engineered and natural environments suffer deleterious effects from biofouling and/or biofilm formation. For instance, bacterial contamination on biomedical devices pose serious health concerns. In membrane-based technologies, such as desalination and wastewater reuse, biofouling decreases membrane lifetime and increases the energy required to produce clean water. Traditionally, approaches have combatted bacteria using bactericidal agents. However, due to globalization, a decline in antibiotic discovery, and the widespread resistance of microbes to many commercial antibiotics and metallic nanoparticles, new materials and approaches to reduce biofilm formation are needed. In this mini-review, we cover the recent strategies that have been explored to combat microbial contamination without exerting evolutionary pressure on microorganisms. Renewable feedstocks, relying on structure-property relationships, bioinspired/nature-derived compounds, and green processing methods are discussed. Greener strategies that mitigate biofouling hold great potential to positively impact human health and safety.

  10. Iodide selective membrane electrodes based on a Molybdenum-Salen as a neutral carrier

    Energy Technology Data Exchange (ETDEWEB)

    Ghanei-Motlagh, Masoud [Department of Chemistry, Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of); Taher, Mohammad Ali, E-mail: ma_taher@yahoo.com [Department of Chemistry, Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of); Ahmadi, Kyoumars [AJA University of Medical Sciences, Tehran (Iran, Islamic Republic of); Sheikhshoaie, Iran [Department of Chemistry, Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of)

    2011-12-01

    A new polymeric membrane electrode (PME) and a coated platinum disk electrode (CPtE) based on Schiff base complex of Mo(VI) as a suitable carrier for I{sup -} ion were described. The influence of membrane composition, pH and possible interfering anions were investigated on the response properties of the electrodes. The electrodes exhibited a Nernstian slope of 63.0 {+-} 0.5 (CPtE) and 60.3 {+-} 0.4 (PME) mV decade{sup -1} in I{sup -} ion over a wide concentration range from 7.9 x 10{sup -7} to 1.0 x 10{sup -1} M for CPtE and 9.1 x 10{sup -6} to 1.0 x 10{sup -1} M I{sup -} for PME. The potentiometric response of the electrodes was independent of the pH of the test solution in the pH range 2.0-8.5 with a fast response time (< 10 s). The process of transfer of iodide across the membrane interface was investigated by use of the AC impedance technique. The proposed sensors were successfully applied to direct determination of iodide in samples containing interfering anions, waste water and as indicator electrodes in precipitation titrations. Highlights: {yields} We study new selective membrane electrodes for iodide ions. {yields} To the best of our knowledge this is the first coated platinum disk electrode of I{sup -}. {yields} The sensors have a wide concentration range with a fast response time. {yields} Efforts have been made to improve the selectivity with the use of CPtE.

  11. Radiolytic preparation of ETFE and PFA based anion exchange membranes for alkaline fuel cell

    International Nuclear Information System (INIS)

    Ko, Beom-Seok; Sohn, Joon-Yong; Nho, Young-Chang; Shin, Junhwa

    2011-01-01

    In this study, a versatile monomer, vinylbenzyl chloride (VBC) was radiolytically grafted onto a partially fluorinated ETFE and perfluorinated polymer PFA films. The VBC grafted films were treated with trimethylamine to prepare the alkaline anion exchange membranes (AAEMs). No significant differences in the ion exchange capacities and water uptakes were observed between the ETFE and PFA based AAEMs with similar degree of grafting (DOG). However, the distribution patterns of the graft chains over the cross-section of the ETFE and PFA based AAEMs were found to be quite different; the even distribution was observed from the ETFE based AAEMs while the uneven distribution was observed from the PFA based AAEMs. It was also found that the PFA based AAEMs have the higher ionic conductivity and chemical stability, compared to the ETFE based AAEMs.

  12. A Fluid Membrane-Based Soluble Ligand Display System for Live CellAssays

    Energy Technology Data Exchange (ETDEWEB)

    Nam, Jwa-Min; Nair, Pradeep N.; Neve, Richard M.; Gray, Joe W.; Groves, Jay T.

    2005-10-14

    Cell communication modulates numerous biological processes including proliferation, apoptosis, motility, invasion and differentiation. Correspondingly, there has been significant interest in the development of surface display strategies for the presentation of signaling molecules to living cells. This effort has primarily focused on naturally surface-bound ligands, such as extracellular matrix components and cell membranes. Soluble ligands (e.g. growth factors and cytokines) play an important role in intercellular communications, and their display in a surface-bound format would be of great utility in the design of array-based live cell assays. Recently, several cell microarray systems that display cDNA, RNAi, or small molecules in a surface array format were proven to be useful in accelerating high-throughput functional genetic studies and screening therapeutic agents. These surface display methods provide a flexible platform for the systematic, combinatorial investigation of genes and small molecules affecting cellular processes and phenotypes of interest. In an analogous sense, it would be an important advance if one could display soluble signaling ligands in a surface assay format that allows for systematic, patterned presentation of soluble ligands to live cells. Such a technique would make it possible to examine cellular phenotypes of interest in a parallel format with soluble signaling ligands as one of the display parameters. Herein we report a ligand-modified fluid supported lipid bilayer (SLB) assay system that can be used to functionally display soluble ligands to cells in situ (Figure 1A). By displaying soluble ligands on a SLB surface, both solution behavior (the ability to become locally enriched by reaction-diffusion processes) and solid behavior (the ability to control the spatial location of the ligands in an open system) could be combined. The method reported herein benefits from the naturally fluid state of the supported membrane, which allows

  13. Polymeric membrane sensors based on Cd(II) Schiff base complexes for selective iodide determination in environmental and medicinal samples.

    Science.gov (United States)

    Singh, Ashok Kumar; Mehtab, Sameena

    2008-01-15

    The two cadmium chelates of schiff bases, N,N'-bis(salicylidene)-1,4-diaminobutane, (Cd-S(1)) and N,N'-bis(salicylidene)-3,4-diaminotoluene (Cd-S(2)), have been synthesized and explored as ionophores for preparing PVC-based membrane sensors selective to iodide(I) ion. Potentiometric investigations indicate high affinity of these receptors for iodide ion. Polyvinyl chloride (PVC)-based membranes of Cd-S(1) and Cd-S(2) using as hexadecyltrimethylammonium bromide (HTAB) cation discriminator and o-nitrophenyloctyl ether (o-NPOE), dibutylphthalate (DBP), acetophenone (AP) and tributylphosphate (TBP) as plasticizing solvent mediators were prepared and investigated as iodide-selective sensors. The best performance was shown by the membrane of composition (w/w) of (Cd-S(1)) (7%):PVC (31%):DBP (60%):HTAB (2%). The sensor works well over a wide concentration range 5.3x10(-7) to 1.0x10(-2)M with Nernstian compliance (59.2mVdecade(-1) of activity) within pH range 2.5-9.0 with a response time of 11s and showed good selectivity for iodide ion over a number of anions. The sensor exhibits adequate life (3 months) with good reproducibility (S.D.+/-0.24mV) and could be used successfully for the determination of iodide content in environmental water samples and mouth wash samples.

  14. Nonlinear observer-based Lyapunov boundary control of distributed heat transfer mechanisms for membrane distillation plant

    KAUST Repository

    Eleiwi, Fadi

    2016-09-19

    This paper presents a nonlinear observer-based Lyapunov control for a membrane distillation (MD) process. The control considers the inlet temperatures of the feed and the permeate solutions as inputs, transforming it to boundary control process, and seeks to maintain the temperature difference along the membrane boundaries around a sufficient level to promote water production. MD process is modeled with advection diffusion equation model in two dimensions, where the diffusion and convection heat transfer mechanisms are best described. Model analysis, effective order reduction and parameters physical interpretation, are provided. Moreover, a nonlinear observer has been designed to provide the control with estimates of the temperature evolution at each time instant. In addition, physical constraints are imposed on the control to have an acceptable range of feasible inputs, and consequently, better energy consumption. Numerical simulations for the complete process with real membrane parameter values are provided, in addition to detailed explanations for the role of the controller and the observer. (C) 2016 Elsevier Ltd. All rights reserved.

  15. Design of air blast pressure sensors based on miniature silicon membrane and piezoresistive gauges

    Science.gov (United States)

    Riondet, J.; Coustou, A.; Aubert, H.; Pons, P.; Lavayssière, M.; Luc, J.; Lefrançois, A.

    2017-11-01

    Available commercial piezoelectric pressure sensors are not able to accurately reproduce the ultra-fast transient pressure occurring during an air blast experiment. In this communication a new pressure sensor prototype based on a miniature silicon membrane and piezoresistive gauges is reported for significantly improving the performances in terms of time response. Simulation results demonstrate the feasibility of a pressure transducer having a fundamental resonant frequency almost ten times greater than the commercial piezoelectric sensors one. The sensor uses a 5μm-thick SOI membrane and four P-type silicon gauges (doping level ≅ 1019 at/cm3) in Wheatstone bridge configuration. To obtain a good trade-off between the fundamental mechanical resonant frequency and pressure sensitivity values, the typical dimension of the rectangular membrane is fixed to 30μm x 90μm with gauge dimension of 1μm x 5μm. The achieved simulated mechanical resonant frequency of these configuration is greater than 40MHz with a sensitivity of 0.04% per bar.

  16. Performance Evaluation of Membrane-Based Septic Tank and Its Reuse Potential for Irrigating Crops.

    Science.gov (United States)

    Khalid, Mehwish; Hashmi, Imran; Khan, Sher Jamal

    2017-08-01

    Membrane technology, being the most emerging wastewater treatment option, has gained substantial importance with the massive objective of the reuse potential of wastewater. Keeping this in view, the present study was conducted with the rationale to evaluate the performance efficiency of membrane-based septic tank (MBST), and its reuse perspective for irrigating crops. The septic tank was designed by submerging a woven fiber microfiltration membrane module to treat domestic wastewater. Three crops Triticum aestivum (wheat), Coriandrum sativum (coriander), and Mentha arvensis (mint) were selected to be irrigated with treated MBST effluent, untreated wastewater, and tap water (as a control) for comparative growth analysis. Two pathogenic strains, Escherichia coli and Salmonella sp. were selected as reference microbes and their translocation rate was observed in root, shoot, and leaves. Upon maturity, the roots, shoots, and leaves of the above-mentioned plants were aseptically removed for microbiological analysis. Strains were analyzed, using analytical profile index and PCR analysis. Maximum removal efficiencies for MBST in terms of chemical oxygen demand (COD), turbidity, nutrients deduction (phosphorus), and indicator bacteria (Escherichia coli) were found to be 73, 96, 48, and 88%, respectively. Significant bacterial load reduction (p < 0.001) in terms of E. coli (3.8 log CFU/100 mL) and helminths (2 eggs/L) was observed in treated water. High plant yield was observed when irrigated with treated water as compared to tap water, as minimal nutrient removal (48%) was recorded in treated water, with the germination percentage of 88.8%.

  17. A Hydrogen Ion-Selective Sensor Based on Non-Plasticised Methacrylic-acrylic Membranes

    Directory of Open Access Journals (Sweden)

    Musa Ahmad

    2002-08-01

    Full Text Available A methacrylic-acrylic polymer was synthesised for use as a non-plasticised membrane for hydrogen ion-selective sensor incorporating tridodecylamine as an ionophore. The copolymer consisted of methyl methacrylate and n-butyl acrylate monomers in a ratio of 2:8. Characterisation of the copolymer using FTNMR demonstrated that the amount of each monomer incorporated during solution polymerisation was found to be similar to the amount used in the feed before polymerisation. The glass transition temperature of the copolymer determined by differential scanning calorimetry was -30.9 ºC. Potentiometric measurements conducted showed a linear pH response range of 4.3 – 9.6 with the response slope of 56.7 mV/decade. The selectivity of the sensors towards hydrogen ions was similar to other plasticiser based membrane electrodes and the logarithmic selectivity coefficients for discrimination against interference cations is close to –9.7. However, the incorporation of a lipophilic anion as membrane additive is essential in ensuring optimum performance of the hydrogen ion sensor.

  18. A membrane-based immunosensor for the analysis of the herbicide isoproturon.

    Science.gov (United States)

    Baskeyfield, Damian E H; Davis, Frank; Magan, Naresh; Tothill, Ibtisam E

    2011-08-12

    A membrane based heterogeneous competitive enzyme-linked immunosorbent assay (ELISA) was used in this work to develop an immunosensor for the detection of a common herbicide, isoproturon. A screen-printed carbon working electrode with carbon counter and silver-silver chloride pseudo-reference electrode was utilized incorporating a membrane fixed into intimate contact with the working electrode to facilitate signal transduction. The membrane containing an immobilized isoproturon-ovalbumin conjugate was laminated onto the carbon working electrode and horseradish peroxidase (HRP) labeled polyclonal antibody was then applied for the competitive assay. Two different amperometric systems, hydroquinone and o-phenylenediamine (OPD) mediation reduction were utilised and the properties of the resultant sensors were compared. A flow injection apparatus was also developed utilising the immunosensor. Limits of detection for isoproturon (LLD(90)) were found to be as low as 0.84 ng mL(-1). The senor was also validated using spiked extracted soil samples and also isoproturon contaminated samples. Copyright © 2011 Elsevier B.V. All rights reserved.

  19. Formaldehyde gas sensor based on TiO2 thin membrane integrated with nano silicon structure

    Science.gov (United States)

    Zheng, Xuan; Ming, An-jie; Ye, Li; Chen, Feng-hua; Sun, Xi-long; Liu, Wei-bing; Li, Chao-bo; Ou, Wen; Wang, Wei-bing; Chen, Da-peng

    2016-07-01

    An innovative formaldehyde gas sensor based on thin membrane type metal oxide of TiO2 layer was designed and fabricated. This sensor under ultraviolet (UV) light emitting diode (LED) illumination exhibits a higher response to formaldehyde than that without UV illumination at low temperature. The sensitivities of the sensor under steady working condition were calculated for different gas concentrations. The sensitivity to formaldehyde of 7.14 mg/m3 is about 15.91 under UV illumination with response time of 580 s and recovery time of 500 s. The device was fabricated through micro-electro-mechanical system (MEMS) processing technology. First, plasma immersion ion implantation (PIII) was adopted to form black polysilicon, then a nanoscale TiO2 membrane with thickness of 53 nm was deposited by DC reactive magnetron sputtering to obtain the sensing layer. By such fabrication approaches, the nanoscale polysilicon presents continuous rough surface with thickness of 50 nm, which could improve the porosity of the sensing membrane. The fabrication process can be mass-produced for the MEMS process compatibility.

  20. Membrane-Based Technologies in the Pharmaceutical Industry and Continuous Production of Polymer-Coated Crystals/Particles.

    Science.gov (United States)

    Chen, Dengyue; Sirkar, Kamalesh K; Jin, Chi; Singh, Dhananjay; Pfeffer, Robert

    2017-01-01

    Membrane technologies are of increasing importance in a variety of separation and purification applications involving liquid phases and gaseous mixtures. Although the most widely used applications at this time are in water treatment including desalination, there are many applications in chemical, food, healthcare, paper and petrochemical industries. This brief review is concerned with existing and emerging applications of various membrane technologies in the pharmaceutical and biopharmaceutical industry. The goal of this review article is to identify important membrane processes and techniques which are being used or proposed to be used in the pharmaceutical and biopharmaceutical operations. How novel membrane processes can be useful for delivery of crystalline/particulate drugs is also of interest. Membrane separation technologies are extensively used in downstream processes for bio-pharmaceutical separation and purification operations via microfiltration, ultrafiltration and diafiltration. Also the new technique of membrane chromatography allows efficient purification of monoclonal antibodies. Membrane filtration techniques of reverse osmosis and nanofiltration are being combined with bioreactors and advanced oxidation processes to treat wastewaters from pharmaceutical plants. Nanofiltration with organic solvent-stable membranes can implement solvent exchange and catalyst recovery during organic solvent-based drug synthesis of pharmaceutical compounds/intermediates. Membranes in the form of hollow fibers can be conveniently used to implement crystallization of pharmaceutical compounds. The novel crystallization methods of solid hollow fiber cooling crystallizer (SHFCC) and porous hollow fiber anti-solvent crystallization (PHFAC) are being developed to provide efficient methods for continuous production of polymer-coated drug crystals in the area of drug delivery. This brief review provides a general introduction to various applications of membrane technologies in

  1. The cell-based L-glutathione protection assays to study endocytosis and recycling of plasma membrane proteins.

    Science.gov (United States)

    Cihil, Kristine M; Swiatecka-Urban, Agnieszka

    2013-12-13

    Membrane trafficking involves transport of proteins from the plasma membrane to the cell interior (i.e. endocytosis) followed by trafficking to lysosomes for degradation or to the plasma membrane for recycling. The cell based L-glutathione protection assays can be used to study endocytosis and recycling of protein receptors, channels, transporters, and adhesion molecules localized at the cell surface. The endocytic assay requires labeling of cell surface proteins with a cell membrane impermeable biotin containing a disulfide bond and the N-hydroxysuccinimide (NHS) ester at 4 ºC - a temperature at which membrane trafficking does not occur. Endocytosis of biotinylated plasma membrane proteins is induced by incubation at 37 ºC. Next, the temperature is decreased again to 4 ºC to stop endocytic trafficking and the disulfide bond in biotin covalently attached to proteins that have remained at the plasma membrane is reduced with L-glutathione. At this point, only proteins that were endocytosed remain protected from L-glutathione and thus remain biotinylated. After cell lysis, biotinylated proteins are isolated with streptavidin agarose, eluted from agarose, and the biotinylated protein of interest is detected by western blotting. During the recycling assay, after biotinylation cells are incubated at 37 °C to load endocytic vesicles with biotinylated proteins and the disulfide bond in biotin covalently attached to proteins remaining at the plasma membrane is reduced with L-glutathione at 4 ºC as in the endocytic assay. Next, cells are incubated again at 37 °C to allow biotinylated proteins from endocytic vesicles to recycle to the plasma membrane. Cells are then incubated at 4 ºC, and the disulfide bond in biotin attached to proteins that recycled to the plasma membranes is reduced with L-glutathione. The biotinylated proteins protected from L-glutathione are those that did not recycle to the plasma membrane.

  2. Development of Nanostructured Water Treatment Membranes Based on Thermotropic Liquid Crystals: Molecular Design of Sub-Nanoporous Materials.

    Science.gov (United States)

    Sakamoto, Takeshi; Ogawa, Takafumi; Nada, Hiroki; Nakatsuji, Koji; Mitani, Masato; Soberats, Bartolome; Kawata, Ken; Yoshio, Masafumi; Tomioka, Hiroki; Sasaki, Takao; Kimura, Masahiro; Henmi, Masahiro; Kato, Takashi

    2018-01-01

    Supply of safe fresh water is currently one of the most important global issues. Membranes technologies are essential to treat water efficiently with low costs and energy consumption. Here, the development of self-organized nanostructured water treatment membranes based on ionic liquid crystals composed of ammonium, imidazolium, and pyridinium moieties is reported. Membranes with preserved 1D or 3D self-organized sub-nanopores are obtained by photopolymerization of ionic columnar or bicontinuous cubic liquid crystals. These membranes show salt rejection ability, ion selectivity, and excellent water permeability. The relationships between the structures and the transport properties of water molecules and ionic solutes in the sub-nanopores in the membranes are examined by molecular dynamics simulations. The results suggest that the volume of vacant space in the nanochannel greatly affects the water and ion permeability.

  3. Preparation of fluoropolymer-based ion-track membranes. Structure of latent tracks and pretreatment effect

    International Nuclear Information System (INIS)

    Yamaki, Tetsuya; Nuryanthi, Nuryanthi; Koshikawa, Hiroshi; Sawada, Shinichi; Hakoda, Teruyuki; Hasegawa, Shin; Asano, Masaharu; Maekawa, Yasunari

    2012-01-01

    High-energy heavy-ion induced damage, called latent tracks m organic polymers can sometimes be etched out chemically to give submicro- and nano-sized pores. Our focus is placed on ion-track membranes of poly(vinylidene fluoride) (PVDF), a type of fluoropolymer, which were previously considered as a matrix of polymer electrolyte fuel-cell membranes. There have been no optimized methods of preparing the PVDF-based ion-track membranes. We thus examined chemical structures of the defects created in the track, and accordingly, presented a pretreatment technique for achieving more efficient track etching. A 25 μm-thick PVDF film was bombarded with 1.1 GeV 238 U or 450 MeV 129 Xe ions. In the multi-purpose chamber, degradation processes were monitored in-situ by FT-IR spectroscopy and residual gas analysis as a function of the fluence up to 6.0 x 10 11 ions/cm 2 . The films irradiated at 8 ions/cm 2 were etched in a 9 M KOH aqueous solution at 80degC. We also performed the conductometric etching, which allows monitoring of pore evolution versus etching time by recording the electrical conductance through the membrane. At fluences above 1 x 10 10 ions/cm 2 , the film showed two new absorption bands identified as double-bond stretching vibrations of in-chain unsaturations -CH=CF- and fluorinated vinyl groups -CF 2 CH=CF 2 . These defects would result from the evolution of HF. The knowledge of the solubility in a permanganate alkaline solution and our preliminary experiment suggested the importance of oxidized tracks for the easy introduction of the etching agent. We finally found that the pretreatment with ozone could oxidize the double bonds in the tracks, thereby vigorously promoting track etching before breakthrough. (author)

  4. A co-cultured skin model based on cell support membranes

    International Nuclear Information System (INIS)

    Dai, N.-T.; Yeh, M.-K.; Liu, Demeral David; Adams, E.F.; Chiang, C.-H.; Yen, C.-Y.; Shih, C.-M.; Sytwu, H.-K.; Chen, Tim-Mo; Wang, H.-J.; Williamson, M.R.; Coombes, A.G.A.

    2005-01-01

    Tissue engineering of skin based on collagen: PCL biocomposites using a designed co-culture system is reported. The collagen: PCL biocomposites having collagen: PCL (w/w) ratios of 1:4, 1:8, and 1:20 have been proven to be biocompatible materials to support both adult normal human epidermal Keratinocyte (NHEK) and mouse 3T3 fibroblast growth in cell culture, respectively, by Dai, Coombes, et al. in 2004. Films of collagen: PCL biocomposites were prepared using non-crosslinking method by impregnation of lyophilized collagen mats with PCL/dichloromethane solutions followed by solvent evaporation. To mimic the dermal/epidermal structure of skin, the 1:20 collagen: PCL biocomposites were selected for a feasibility study of a designed co-culture technique that would subsequently be used for preparing fibroblast/biocomposite/keratinocyte skin models. A 55.3% increase in cell number was measured in the designed co-culture system when fibroblasts were seeded on both sides of a biocomposite film compared with cell culture on one surface of the biocomposite in the feasibility study. The co-culture of human keratinocytes and 3T3 fibroblasts on each side of the membrane was therefore studied using the same co-culture system by growing keratinocytes on the top surface of membrane for 3 days and 3T3 fibroblasts underneath the membrane for 6 days. Scanning electron microscopy (SEM) and immunohistochemistry assay revealed good cell attachment and proliferation of both human keratinocytes and 3T3 fibroblasts with these two types of cells isolated well on each side of the membrane. Using a modified co-culture technique, a co-cultured skin model presenting a confluent epidermal sheet on one side of the biocomposite film and fibroblasts populated on the other side of the film was developed successfully in co-culture system for 28 days under investigations by SEM and immunohistochemistry assay. Thus, the design of a co-culture system based on 1:20 (w/w) collagen: PCL biocomposite

  5. Tuning PIM-PI-Based Membranes for Highly Selective Transport of Propylene/Propane

    KAUST Repository

    Swaidan, Ramy J.

    2016-12-06

    To date there exists a great deal of energetic and economic inefficiency in the separation of olefins from paraffins because the principal means of achieving industrial purity requirements is accomplished with very energy intensive cryogenic distillation. Mitigation of the severe energy intensity of the propylene/propane separation has been identified as one of seven chemical separations which can change the landscape of global energy use, and membranes have been targeted as an emerging technology because they offer scalability and lower capital and operating costs. The focus of this work was to evaluate a new direction of material development for the very industrially relevant propylene/propane separation using membranes. The objective was to develop a rational design approach for generating highly selective membranes using a relatively new platform of materials known as polyimides of intrinsic microporosity (PIM-PIs), the prospects of which have never been examined for the propylene/propane separation. Structurally, PIMs comprise relatively inflexible macromolecular architectures integrating contortion sites that help disrupt packing and trap microporous free volume elements (< 20 Å). To date most of the work reported in the literature on this separation is based on conventional low free volume 6FDA-based polyimides which in the best case show moderate C3H6/C3H8 selectivities (<20) with C3H6 permeabilities too low to garner industrial interest. Due to propylene and propane’s relatively large molecular size, we hypothesized that the use of more open structures can provide greater accessibility to the pores necessary to enhance membrane sieving and flux. It has been shown for numerous key gas separations that introduction of microporosity into a polymer structure can defy the notorious permeability/selectivity tradeoff curve and induce simultaneous boosts in both permeability and selectivity. The cornerstone approach to designing state of the art high

  6. Solution phase and membrane immobilized iron-based free radical reactions: Fundamentals and applications for water treatment

    Science.gov (United States)

    Lewis, Scott Romak

    Membrane-based separation processes have been used extensively for drinking water purification, wastewater treatment, and numerous other applications. Reactive membranes synthesized through functionalization of the membrane pores offer enhanced reactivity due to increased surface area at the polymer-solution interface and low diffusion limitations. Oxidative techniques utilizing free radicals have proven effective for both the destruction of toxic organics and non-environmental applications. Most previous work focuses on reactions in the homogeneous phase; however, the immobilization of reactants in membrane pores offers several advantages. The use of polyanions immobilized in a membrane or chelates in solution prevents ferric hydroxide precipitation at near-neutral pH, a common limitation of iron(Fe(II/III))-catalyzed hydrogen peroxide (H 2O2) decomposition. The objectives of this research are to develop a membrane-based platform for the generation of free radicals, degrade toxic organic compounds using this and similar solution-based reactions, degrade toxic organic compounds in droplet form, quantify hydroxyl radical production in these reactions, and develop kinetic models for both processes. In this study, a functionalized membrane containing poly(acrylic acid) (PAA) was used to immobilize iron ions and conduct free radical reactions by permeating H2O2 through the membrane. The membrane's responsive behavior to pH and divalent cations was investigated and modeled. The conversion of Fe(II) to Fe(III) in the membrane and its effect on the decomposition of hydrogen peroxide were monitored and used to develop kinetic models for predicting H2O2 decomposition in these systems. The rate of hydroxyl radical production, and hence contaminant degradation can be varied by changing the residence time, H2O2 concentration, and/or iron loading. Using these membrane-immobilized systems, successful removal of toxic organic compounds, such as pentachlorophenol (PCP), from water

  7. Review of Supported Pd-Based Membranes Preparation by Electroless Plating for Ultra-Pure Hydrogen Production.

    Science.gov (United States)

    Alique, David; Martinez-Diaz, David; Sanz, Raul; Calles, Jose A

    2018-01-23

    In the last years, hydrogen has been considered as a promising energy vector for the oncoming modification of the current energy sector, mainly based on fossil fuels. Hydrogen can be produced from water with no significant pollutant emissions but in the nearest future its production from different hydrocarbon raw materials by thermochemical processes seems to be more feasible. In any case, a mixture of gaseous compounds containing hydrogen is produced, so a further purification step is needed to purify the hydrogen up to required levels accordingly to the final application, i.e., PEM fuel cells. In this mean, membrane technology is one of the available separation options, providing an efficient solution at reasonable cost. Particularly, dense palladium-based membranes have been proposed as an ideal chance in hydrogen purification due to the nearly complete hydrogen selectivity (ideally 100%), high thermal stability and mechanical resistance. Moreover, these membranes can be used in a membrane reactor, offering the possibility to combine both the chemical reaction for hydrogen production and the purification step in a unique device. There are many papers in the literature regarding the preparation of Pd-based membranes, trying to improve the properties of these materials in terms of permeability, thermal and mechanical resistance, poisoning and cost-efficiency. In this review, the most relevant advances in the preparation of supported Pd-based membranes for hydrogen production in recent years are presented. The work is mainly focused in the incorporation of the hydrogen selective layer (palladium or palladium-based alloy) by the electroless plating, since it is one of the most promising alternatives for a real industrial application of these membranes. The information is organized in different sections including: (i) a general introduction; (ii) raw commercial and modified membrane supports; (iii) metal deposition insights by electroless-plating; (iv) trends in

  8. Multiplexed Imaging of Protein Phosphorylation on Membranes Based on Ti(IV) Functionalized Nanopolymers.

    Science.gov (United States)

    Iliuk, Anton; Li, Li; Melesse, Michael; Hall, Mark C; Tao, W Andy

    2016-05-17

    Accurate protein phosphorylation analysis reveals dynamic cellular signaling events not evident from protein expression levels. The most dominant biochemical assay, western blotting, suffers from the inadequate availability and poor quality of phospho-specific antibodies for phosphorylated proteins. Furthermore, multiplexed assays based on antibodies are limited by steric interference between the antibodies. Here we introduce a multifunctionalized nanopolymer for the universal detection of phosphoproteins that, in combination with regular antibodies, allows multiplexed imaging and accurate determination of protein phosphorylation on membranes. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. A quasi-direct methanol fuel cell system based on blend polymer membrane electrolytes

    DEFF Research Database (Denmark)

    Li, Qingfeng; Hjuler, Hans Aage; Hasiotis, C.

    2002-01-01

    , compared to less than 100 ppm CO for the Nafion-based technology at 80degrees C. The high CO tolerance makes it possible to use the reformed hydrogen directly from a simple methanol reformer without further CO removal. That both the fuel cell and the methanol reformer operate at temperatures around 200......On the basis of blend polymer electrolytes of polybenzimidazole and sulfonated polysulfone, a polymer electrolyte membrane fuel cell was developed with an operational temperature up to 200degrees C. Due to the high operational temperature, the fuel cell can tolerate 1.0-3.0 vol % CO in the fuel...

  10. Paper-based microfluidics with high resolution, cut on a glass fiber membrane for bioassays.

    Science.gov (United States)

    Fang, Xueen; Wei, Shasha; Kong, Jilie

    2014-03-07

    In this report, we describe a simple, low-cost, straight forward and highly reproducible fabrication method of microfluidic systems. This system was cut on a glass fiber membrane by a common cutter without using any other sophisticated equipment or organic solvents. This format represents a novel type of paper-based microfluidics with high resolution of the microchannel down to ~137 μm, comparable to those made by conventional photolithography. We successfully applied this method to microfluidics to create a star micro-array format of multiplexed urine tests in this study.

  11. Humidifier prevents corrosion and legionella and saves water and energy; Bevochtigingssysteem voorkomt corrosie en legionella en bespaart water en energie

    Energy Technology Data Exchange (ETDEWEB)

    Huizinga, H.T. [Heat Transfer Holland, Zuidwolde (Netherlands)

    2009-04-15

    The renewal of the central water humidifier in the laboratory of DSM-Resins (chemical industry) in Zwolle, Netherlands, leads to a better air conditioning system and prevents corrosion and legionella. At the same time, water and energy consumption are substantially reduced. This renewal fits perfectly within DSM's company policy to decrease the annual energy consumption by 2 %. [Dutch] Het vernieuwen van het centrale waterbevochtigingssysteem in het laboratorium van DSM-Resins te Zwolle verbetert het luchtbehandelingssysteem en voorkomt corrosie en legionella. Tevens vindt er een besparing plaats in water en energiegebruik. Deze vernieuwing past in de beleidsdoelstelling van DSM om iedere jaar 2% minder energie te gebruiken.

  12. Computational Screening of MOF-Based Mixed Matrix Membranes for CO2/N2 Separations

    Directory of Open Access Journals (Sweden)

    Zeynep Sumer

    2016-01-01

    Full Text Available Atomically detailed simulations were used to examine CO2/N2 separation potential of metal organic framework- (MOF- based mixed matrix membranes (MMMs in this study. Gas permeability and selectivity of 700 new MMMs composed of 70 different MOFs and 10 different polymers were calculated for CO2/N2 separation. This is the largest number of MOF-based MMMs for which computational screening is done to date. Selecting the appropriate MOFs as filler particles in polymers resulted in MMMs that have higher CO2/N2 selectivities and higher CO2 permeabilities compared to pure polymer membranes. We showed that, for polymers that have low CO2 permeabilities but high CO2 selectivities, the identity of the MOF used as filler is not important. All MOFs enhanced the CO2 permeabilities of this type of polymers without changing their selectivities. Several MOF-based MMMs were identified to exceed the upper bound established for polymers. The methods we introduced in this study will create many opportunities to select the MOF/polymer combinations with useful properties for CO2 separation applications.

  13. Application of the mass-based UNIQUAC model to membrane systems: A critical revision

    International Nuclear Information System (INIS)

    Chovau, S.; Van der Bruggen, B.; Luis, P.

    2012-01-01

    Highlights: ► UNIQUAC model in mass-based terms is considered for the description of sorption equilibria in membrane systems. ► Model validation of molar and mass-based model is performed on simple (vapor + liquid) equilibrium. ► Discrepancy is found between molar and mass-based model, which is attributed to an incorrect conversion. ► Novel model based on correct thermodynamics is provided for future research. - Abstract: The UNIQUAC model is very suitable in describing (liquid + liquid) as well as (vapor + liquid) equilibrium for a wide range of systems. It can be extended to (solvent + polymer) systems for describing sorption equilibria. The original model is expressed in molar-based terms, but requires knowledge of structural parameters and molar masses of all components. Since these cannot always be easily determined for membranes, a conversion to mass-based terms is often performed, which eliminates this issue. Many studies use this model to calculate sorption equilibria in (solvent + polymer) systems. Nevertheless, in this work the conversion from molar to mass-based parameters is postulated to be erroneous. This even leads to an incorrect description of simple (vapor + liquid) equilibrium of pure liquid mixtures and hence it is advised not to use this model for further modeling of sorption equilibrium in (solvent + polymer) systems. In this paper, the errors in the conversion are pinpointed, and the effects it can have on the description of (vapor + liquid) equilibrium, if used improvident, are demonstrated. Furthermore, it is shown that in fact a simple and straightforward conversion can be performed. Finally, in the case when polymers are involved, an adaption and simplification to the model was successfully applied.

  14. Development of a membrane adsorber based capture step for the purification of yellow fever virus.

    Science.gov (United States)

    Pato, Tânia P; Souza, Marta Cristina O; Silva, Andréa N M R; Pereira, Renata C; Silva, Marlon V; Caride, Elena; Gaspar, Luciane P; Freire, Marcos S; Castilho, Leda R

    2014-05-19

    Yellow fever (YF) is an endemic disease in some tropical areas of South America and Africa that presents lethality rate between 20 and 50%. There is no specific treatment and to control this disease a highly effective live-attenuated egg based vaccine is widely used for travelers and residents of areas where YF is endemic. However, recent reports of rare, sometimes fatal, adverse events post-vaccination have raised concerns. In order to increase safety records, alternative strategies should be considered, such as developing a new inactivated vaccine using a cell culture based technology, capable of meeting the demands in cases of epidemic. With this goal, the production of YF virus in Vero cells grown on microcarriers and its subsequent purification by chromatographic techniques was studied. In this work we investigate the capture step of the purification process of the YF virus. At first, virus stability was studied over a wide pH range, showing best results for the alkaline region. Considering this result and the pI of the envelope protein previously determined in silico, a strong anion exchanger was considered most suitable. Due to the easy scalability, simplicity to handle, absence of diffusional limitations and suitability for virus handling of membrane adsorbers, a Q membrane was evaluated. The amount of antigen adsorbed onto the membrane was investigated within the pH range for virus stability, and the best pH for virus adsorption was considered to be 8.5. Finally, studies on gradient and step elution allowed to determine the most adequate salt concentration for washing (0.15M) and virus elution (0.30 M). Under these operating conditions, it was shown that this capture step is quite efficient, showing high product recovery (93.2±30.3%) and efficient DNA clearance (0.9±0.3 ng/dose). Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Nano level detection of Cd(II) using poly(vinyl chloride) based membranes of Schiff bases.

    Science.gov (United States)

    Gupta, Vinod K; Al Khayat, Maysoon; Singh, Ashok K; Pal, Manoj K

    2009-02-16

    The construction and performance characteristics of polymeric membrane electrodes based on two neutral ionophores, 2,2'-(1Z,1'Z)-(1E,1'E)-(1,2-phenylenebis(methan-1-yl-1-ylidene))bis(azaan-1-yl-1-ylidene)bis(methylene)bis(azan-1-yl-1-ylidene)bis(methan-1-yl-ylidene)diphenol (L(1)) and 4,4'-(1E,1'E)-(butane-1,4-diylbis(azan-1-yl-1-ylidene))bis(methan-1-yl-1-ylidene)dinaphthalen-1-ol (L(2)) for quantification of cadmium ions, are described. The influences of membrane compositions on the potentiometric response of the electrodes have been found to substantially improve the performance characteristics. The best performance was obtained with the electrode having a membrane composition (w/w) of (L(1)) (2.6%):PVC (31.6%):DOP (63.2%):NaTPB (2.6%). The proposed electrode exhibits Nernstian response in the concentration range 5.0 x 10(-9) to 1.0 x 10(-1)M Cd(2+) with limit of detection 3.1 x 10(-9), performs satisfactorily over wide pH range (2.0-8.5) with a fast response time (11s). The electrode has been found to work satisfactorily in partially non-aqueous media up to 40% (v/v) content of methanol, ethanol and acetonitrile and could be used for a period of 2.5 months. The analytical usefulness of the proposed electrode has been evaluated by its application in the determination of cadmium in cigarette samples. The practical utility of the membrane electrode has also been observed in the presence of surfactants.

  16. Nano level detection of Cd(II) using poly(vinyl chloride) based membranes of Schiff bases

    International Nuclear Information System (INIS)

    Gupta, Vinod K.; Al Khayat, Maysoon; Singh, Ashok K.; Pal, Manoj K.

    2009-01-01

    The construction and performance characteristics of polymeric membrane electrodes based on two neutral ionophores, 2,2'-(1Z,1'Z)-(1E,1'E)-(1,2-phenylenebis(methan-1-yl-1-ylidene)) bis(azaan-1-yl-1-ylidene)bis(methylene)bis(azan-1-yl-1-ylidene) bis(methan-1-yl-ylidene)diphenol (L 1 ) and 4,4'-(1E,1'E)-(butane-1,4-diylbis(azan-1-yl-1-ylidene)) bis(methan-1-yl-1-ylidene)dinaphthalen-1-ol (L 2 ) for quantification of cadmium ions, are described. The influences of membrane compositions on the potentiometric response of the electrodes have been found to substantially improve the performance characteristics. The best performance was obtained with the electrode having a membrane composition (w/w) of (L 1 ) (2.6%):PVC (31.6%):DOP (63.2%):NaTPB (2.6%). The proposed electrode exhibits Nernstian response in the concentration range 5.0 x 10 -9 to 1.0 x 10 -1 M Cd 2+ with limit of detection 3.1 x 10 -9 , performs satisfactorily over wide pH range (2.0-8.5) with a fast response time (11 s). The electrode has been found to work satisfactorily in partially non-aqueous media up to 40% (v/v) content of methanol, ethanol and acetonitrile and could be used for a period of 2.5 months. The analytical usefulness of the proposed electrode has been evaluated by its application in the determination of cadmium in cigarette samples. The practical utility of the membrane electrode has also been observed in the presence of surfactants

  17. Nano level detection of Cd(II) using poly(vinyl chloride) based membranes of Schiff bases

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Vinod K. [Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee 247 667 (India)], E-mail: vinodfcy@iitr.ernet.in; Al Khayat, Maysoon [Department of Chemistry, College of Sciences, University of Sharjah, Sharjah (United Arab Emirates); Singh, Ashok K.; Pal, Manoj K. [Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee 247 667 (India)

    2009-02-16

    The construction and performance characteristics of polymeric membrane electrodes based on two neutral ionophores, 2,2'-(1Z,1'Z)-(1E,1'E)-(1,2-phenylenebis(methan-1-yl-1-ylidene)) bis(azaan-1-yl-1-ylidene)bis(methylene)bis(azan-1-yl-1-ylidene) bis(methan-1-yl-ylidene)diphenol (L{sub 1}) and 4,4'-(1E,1'E)-(butane-1,4-diylbis(azan-1-yl-1-ylidene)) bis(methan-1-yl-1-ylidene)dinaphthalen-1-ol (L{sub 2}) for quantification of cadmium ions, are described. The influences of membrane compositions on the potentiometric response of the electrodes have been found to substantially improve the performance characteristics. The best performance was obtained with the electrode having a membrane composition (w/w) of (L{sub 1}) (2.6%):PVC (31.6%):DOP (63.2%):NaTPB (2.6%). The proposed electrode exhibits Nernstian response in the concentration range 5.0 x 10{sup -9} to 1.0 x 10{sup -1} M Cd{sup 2+} with limit of detection 3.1 x 10{sup -9}, performs satisfactorily over wide pH range (2.0-8.5) with a fast response time (11 s). The electrode has been found to work satisfactorily in partially non-aqueous media up to 40% (v/v) content of methanol, ethanol and acetonitrile and could be used for a period of 2.5 months. The analytical usefulness of the proposed electrode has been evaluated by its application in the determination of cadmium in cigarette samples. The practical utility of the membrane electrode has also been observed in the presence of surfactants.

  18. Comparing and Contrasting Traditional Membrane Bioreactor Models with Novel Ones Based on Time Series Analysis

    Directory of Open Access Journals (Sweden)

    Parneet Paul

    2013-02-01

    Full Text Available The computer modelling and simulation of wastewater treatment plant and their specific technologies, such as membrane bioreactors (MBRs, are becoming increasingly useful to consultant engineers when designing, upgrading, retrofitting, operating and controlling these plant. This research uses traditional phenomenological mechanistic models based on MBR filtration and biochemical processes to measure the effectiveness of alternative and novel time series models based upon input–output system identification methods. Both model types are calibrated and validated using similar plant layouts and data sets derived for this purpose. Results prove that although both approaches have their advantages, they also have specific disadvantages as well. In conclusion, the MBR plant designer and/or operator who wishes to use good quality, calibrated models to gain a better understanding of their process, should carefully consider which model type is selected based upon on what their initial modelling objectives are. Each situation usually proves unique.

  19. Poly(hydroxyethyl methacrylate) based affinity membranes for in vitro removal of anti-dsDNA antibodies from SLE plasma.

    Science.gov (United States)

    Uzun, Lokman; Yavuz, Handan; Osman, Bilgen; Celik, Hamdi; Denizli, Adil

    2010-07-01

    The preparation of polymeric membrane using affinity technology for application in blood filtration devices is described here. DNA attached poly(hydroxyethyl methacrylate) (PHEMA) based microporous affinity membrane was prepared for selective removal of anti-dsDNA antibodies from systemic lupus erythematosus (SLE) patient plasma in in vitro. In order to further increase blood-compatibility of affinity membrane, aminoacid based comonomer N-methacryloyl-L-alanine (MAAL) was included in the polymerization recipe. PHEMAAL membrane was produced by a photopolymerization technique and then characterized by swelling tests and scanning electron microscope (SEM) studies. Blood-compatibility tests were also performed. The water swelling ratio of PHEMAAL membrane increased significantly (133.2%) compared with PHEMA (58%). PHEMAAL membrane has large pores around in the range of 5-10 microm. All the clotting times increased when compared with PHEMA membrane. Loss of platelets and leukocytes was very low. DNA loading was 7.8 mg/g. There was a very low anti-dsDNA-antibody adsorption onto the plain PHEMAAL membrane, about 78 IU/g. The PHEMAAL-DNA membrane adsorbed anti-dsDNA-antibody in the range of 10-68 x 10(3)IU/g from SLE plasma. Anti-dsDNA-antibody concentration decreased significantly from 875 to 144 IU/ml with the time. Anti-dsDNA-antibodies could be repeatedly adsorbed and eluted without noticeable loss in the anti-dsDNA-antibody adsorption amount. (c) 2010 Elsevier B.V. All rights reserved.

  20. A Comparison of Water Diffusion in Polymer Based Fuel Cell and Reverse Osmosis Membrane Materials

    Science.gov (United States)

    Soles, Christopher; Frieberg, Bradley; Tarver, Jacob; Tyagi, Madhusudan; Jeong, Cheol; Chan, Edwin; Stafford, Christopher

    Hydrated polymer membranes are critical in both fuel cells and water filtration and desalination. In both of these applications the membrane function (selectively transporting or separating ions) is coupled with the transport of water through the membrane. There is a significant need to understand the nature by which the water and ions distribute and move through these membranes. This presentation compares the transport mechanisms in in an ion containing block copolymer alkaline fuel cell membrane with that of a polyamide membrane that is used as the active layer in a reverse osmosis water desalination membrane. Small angle neutron scattering measurements are used to locally probe how water swells the different materials and quantitatively describe the distribution of water within the membrane microstructures. Quasielastic neutron scattering measurements are then used to separate the polymer dynamics of the host membranes from the dynamics of the water inside the membranes. This reveals that water moves at least an order of magnitude slower through the ion containing fuel cell membrane materials, consistent with a solution-diffusion model, while the water in the polyamide membranes moves faster, consistent with a pore-flow diffusion mechanism. These insights will be discussed in terms of a coupling of the water and polymer dynamics and design cues for high performance membrane materials.

  1. Intra-operative tissue oxygen tension is increased by local insufflation of humidified-warm CO2 during open abdominal surgery in a rat model.

    Directory of Open Access Journals (Sweden)

    Jean K Marshall

    Full Text Available Maintenance of high tissue oxygenation (PtO2 is recommended during surgery because PtO2 is highly predictive of surgical site infection and colonic anastomotic leakage. However, surgical site perfusion is often sub-optimal, creating an obstructive hurdle for traditional, systemically applied therapies to maintain or increase surgical site PtO2. This research tested the hypothesis that insufflation of humidified-warm CO2 into the abdominal cavity would increase sub-peritoneal PtO2 during open abdominal surgery.15 Wistar rats underwent laparotomy under general anesthesia. Three sets of randomized cross-over experiments were conducted in which the abdominal cavity was subjected to alternating exposure to 1 humidified-warm CO2 & ambient air; 2 humidified-warm CO2 & dry-cold CO2; and 3 dry-cold CO2 & ambient air. Sub-peritoneal PtO2 and tissue temperature were measured with a polarographic oxygen probe.Upon insufflation of humidified-warm CO2, PtO2 increased by 29.8 mmHg (SD 13.3; p<0.001, or 96.6% (SD 51.9, and tissue temperature by 3.0°C (SD 1.7 p<0.001, in comparison with exposure to ambient air. Smaller, but significant, increases in PtO2 were seen in experiments 2 and 3. Tissue temperature decreased upon exposure to dry-cold CO2 compared with ambient air (-1.4°C, SD 0.5, p = 0.001.In a rat model, insufflation of humidified-warm CO2 into the abdominal cavity during open abdominal surgery causes an immediate and potentially clinically significant increase in PtO2. The effect is an additive result of the delivery of CO2 and avoidance of evaporative cooling via the delivery of the CO2 gas humidified at body temperature.

  2. Work of breathing during CPAP and heated humidified high-flow nasal cannula.

    Science.gov (United States)

    Shetty, Sandeep; Hickey, Ann; Rafferty, Gerrard F; Peacock, Janet L; Greenough, Anne

    2016-09-01

    To determine whether continuous positive airway pressure (CPAP) compared with heated humidified, high-flow nasal cannula (HHFNC) in infants with evolving or established bronchopulmonary dysplasia (BPD) reduced the work of breathing (WOB) and thoracoabdominal asynchrony (TAA) and improved oxygen saturation (SaO2). Randomised crossover study. Tertiary neonatal unit. 20 infants (median gestational age of 27.6 weeks (range 24.6-31.9 weeks)) were studied at a median postnatal age of 30.9 weeks (range 28.1-39.1 weeks). Infants were studied on 2 consecutive days. On the first study day, they were randomised to either CPAP or HHFNC each for 2 h, the order being reversed on the second day. The WOB was assessed by measuring the pressure time product of the diaphragm (PTPdi). PTPdi, TAA and SaO2 were assessed during the final 5 min of each 2 h period and the results on the two study days were meaned. There were no significant differences in the results on CPAP versus HHFNC: mean PTPdi 226 (range 126-294) versus 224 cm H2O/s/min (95% CI for difference: -27 to 22; p=0.85) (range 170-318) (p=0.82), mean TAA 13.4° (range 4.51°-23.32°) versus 14.01° (range 4.25°-23.86°) (95% CI for difference: -3.9 to 2.8: p=0.73) (p=0.63) and mean SaO2 95% (range 93%-100%) versus 95% (94%-99%), (95% CI for difference -1.8 to 0.5; p=0.25) (p=0.45). In infants with evolving or established BPD, CPAP compared with HHFNC offered no significant advantage with regard to the WOB, degree of asynchrony or oxygen saturation. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  3. Iodide selective membrane electrodes based on a Molybdenum-Salen as a neutral carrier

    International Nuclear Information System (INIS)

    Ghanei-Motlagh, Masoud; Taher, Mohammad Ali; Ahmadi, Kyoumars; Sheikhshoaie, Iran

    2011-01-01

    A new polymeric membrane electrode (PME) and a coated platinum disk electrode (CPtE) based on Schiff base complex of Mo(VI) as a suitable carrier for I - ion were described. The influence of membrane composition, pH and possible interfering anions were investigated on the response properties of the electrodes. The electrodes exhibited a Nernstian slope of 63.0 ± 0.5 (CPtE) and 60.3 ± 0.4 (PME) mV decade -1 in I - ion over a wide concentration range from 7.9 x 10 -7 to 1.0 x 10 -1 M for CPtE and 9.1 x 10 -6 to 1.0 x 10 -1 M I - for PME. The potentiometric response of the electrodes was independent of the pH of the test solution in the pH range 2.0-8.5 with a fast response time ( - . → The sensors have a wide concentration range with a fast response time. → Efforts have been made to improve the selectivity with the use of CPtE.

  4. Entrapped cells-based-anaerobic membrane bioreactor treating domestic wastewater: Performances, fouling, and bacterial community structure.

    Science.gov (United States)

    Juntawang, Chaipon; Rongsayamanont, Chaiwat; Khan, Eakalak

    2017-11-01

    A laboratory scale study on treatment performances and fouling of entrapped cells-based-anaerobic membrane bioreactor (E-AnMBR) in comparison with suspended cells-based-bioreactor (S-AnMBR) treating domestic wastewater was conducted. The difference between E-AnMBR and S-AnMBR was the uses of cells entrapped in phosphorylated polyvinyl alcohol versus planktonic cells. Bulk organic removal efficiencies by the two AnMBRs were comparable. Lower concentrations of suspended biomass, bound extracellular polymeric substances and soluble microbial products in E-AnMBR resulted in less fouling compared to S-AnMBR. S-AnMBR provided 7 days of operation time versus 11 days for E-AnMBR before chemical cleaning was required. The less frequent chemical cleaning potentially leads to a longer membrane life-span for E-AnMBR compared to S-AnMBR. Phyla Proteobacteria, Chloroflexi, Bacteroidetes and Acidobacteria were dominant in cake sludge from both AnMBRs but their abundances were different between the two AnMBRs, suggesting influence of cell entrapment on the bacteria community. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Energy and economic optimization of a membrane-based oxyfuel steam power plant

    International Nuclear Information System (INIS)

    Nazarko, Yevgeniy

    2015-01-01

    Carbon capture and storage is one technological option for reducing CO 2 emissions. The oxyfuel process is based on the combustion of fossil fuels in an oxygen-flue gas atmosphere with the subsequent concentration of CO 2 . The oxygen is produced by cryogenic air separation with an energy demand of 245 kWh el /t O2 . The application of ceramic membranes has the potential to reduce the specific energy demand of oxygen supply with consistently high-purity oxygen. This work focuses on - determining the efficiency of an advanced oxyfuel steam power plant that can be constructed today using membranes for oxygen production, - investigating and quantifying the potential for energy optimizing the overall process by changing its flow structure, - assessing the feasibility of individual optimization options based on their investment costs under market conditions. For this work, a method developed by Forschungszentrum Juelich and patented on 25 April 2012 under EP 2214806 is used. The Oxy-Vac-Juel concept is integrated into the oxyfuel steam power plant with simple process management using standardized power plant components. The net efficiency of the base power plant is 36.6 percentage points for an oxygen separation degree of 60 %. This corresponds to a net power loss of 9.3 percentage points compared to the reference power plant without CO 2 capture. The specific electricity demand of this oxygen supply method is 176 kWh el /t O2 . To increase the efficiency, the flow structure of the base power plant is optimized using industrially available components from power plant and process engineering. The 22 analyzed optimization options consist of design optimization of the gas separation process, the modification of the flue gas recirculation and the plant-internal waste heat utilization. The energetic advantage over the base power plant, depending on the optimization option, ranges from 0.05 - 1.00 percentage points. For each optimization option, the size and cost of the power

  6. Membrane Processes Based on Complexation Reactions of Pollutants as Sustainable Wastewater Treatments

    Directory of Open Access Journals (Sweden)

    Teresa Poerio

    2009-11-01

    Full Text Available Water is today considered to be a vital and limited resource due to industrial development and population growth. Developing appropriate water treatment techniques, to ensure a sustainable management, represents a key point in the worldwide strategies. By removing both organic and inorganic species using techniques based on coupling membrane processes and appropriate complexing agents to bind pollutants are very important alternatives to classical separation processes in water treatment. Supported Liquid Membrane (SLM and Complexation Ultrafiltration (CP-UF based processes meet the sustainability criteria because they require low amounts of energy compared to pressure driven membrane processes, low amounts of complexing agents and they allow recovery of water and some pollutants (e.g., metals. A more interesting process, on the application point of view, is the Stagnant Sandwich Liquid Membrane (SSwLM, introduced as SLM implementation. It has been studied in the separation of the drug gemfibrozil (GEM and of copper(II as organic and inorganic pollutants in water. Obtained results showed in both cases the higher efficiency of SSwLM with respect to the SLM system configuration. Indeed higher stability (335.5 vs. 23.5 hours for GEM; 182.7 vs. 49.2 for copper(II and higher fluxes (0.662 vs. 0.302 mmol·h-1·m-2 for GEM; 43.3 vs. 31.0 for copper(II were obtained by using the SSwLM. Concerning the CP-UF process, its feasibility was studied in the separation of metals from waters (e.g., from soil washing, giving particular attention to process sustainability such as water and polymer recycle, free metal and water recovery. The selectivity of the CP-UF process was also validated in the separate removal of copper(II and nickel(II both contained in synthetic and real aqueous effluents. Thus, complexation reactions involved in the SSwLM and the CP-UF processes play a key role to meet the sustainability criteria.

  7. Accurate control of oxygen level in cells during culture on silicone rubber membranes with application to stem cell differentiation.

    Science.gov (United States)

    Powers, Daryl E; Millman, Jeffrey R; Bonner-Weir, Susan; Rappel, Michael J; Colton, Clark K

    2010-01-01

    Oxygen level in mammalian cell culture is often controlled by placing culture vessels in humidified incubators with a defined gas phase partial pressure of oxygen (pO(2gas)). Because the cells are consuming oxygen supplied by diffusion, a difference between pO(2gas) and that experienced by the cells (pO(2cell)) arises, which is maximal when cells are cultured in vessels with little or no oxygen permeability. Here, we demonstrate theoretically that highly oxygen-permeable silicone rubber membranes can be used to control pO(2cell) during culture of cells in monolayers and aggregates much more accurately and can achieve more rapid transient response following a disturbance than on polystyrene and fluorinated ethylene-propylene copolymer membranes. Cell attachment on silicone rubber was achieved by physical adsorption of fibronectin or Matrigel. We use these membranes for the differentiation of mouse embryonic stem cells to cardiomyocytes and compare the results with culture on polystyrene or on silicone rubber on top of polystyrene. The fraction of cells that are cardiomyocyte-like increases with decreasing pO(2) only when using oxygen-permeable silicone membrane-based dishs, which contract on silicone rubber but not polystyrene. The high permeability of silicone rubber results in pO(2cell) being equal to pO(2gas) at the tissue-membrane interface. This, together with geometric information from histological sections, facilitates development of a model from which the pO(2) distribution within the resulting aggregates is computed. Silicone rubber membranes have significant advantages over polystyrene in controlling pO(2cell), and these results suggest they are a valuable tool for investigating pO(2) effects in many applications, such as stem cell differentiation. Copyright 2009 American Institute of Chemical Engineers

  8. Membrane-based ethylene/ethane separation: The upper bound and beyond

    KAUST Repository

    Rungta, Meha; Zhang, Chen; Koros, William J.; Xu, Liren

    2013-01-01

    Ethylene/ethane separation via cryogenic distillation is extremely energy-intensive, and membrane separation may provide an attractive alternative. In this paper, ethylene/ethane separation performance using polymeric membranes is summarized

  9. Improvement of a sample preparation method assisted by sodium deoxycholate for mass-spectrometry-based shotgun membrane proteomics.

    Science.gov (United States)

    Lin, Yong; Lin, Haiyan; Liu, Zhonghua; Wang, Kunbo; Yan, Yujun

    2014-11-01

    In current shotgun-proteomics-based biological discovery, the identification of membrane proteins is a challenge. This is especially true for integral membrane proteins due to their highly hydrophobic nature and low abundance. Thus, much effort has been directed at sample preparation strategies such as use of detergents, chaotropes, and organic solvents. We previously described a sample preparation method for shotgun membrane proteomics, the sodium deoxycholate assisted method, which cleverly circumvents many of the challenges associated with traditional sample preparation methods. However, the method is associated with significant sample loss due to the slightly weaker extraction/solubilization ability of sodium deoxycholate when it is used at relatively low concentrations such as 1%. Hence, we present an enhanced sodium deoxycholate sample preparation strategy that first uses a high concentration of sodium deoxycholate (5%) to lyse membranes and extract/solubilize hydrophobic membrane proteins, and then dilutes the detergent to 1% for a more efficient digestion. We then applied the improved method to shotgun analysis of proteins from rat liver membrane enriched fraction. Compared with other representative sample preparation strategies including our previous sodium deoxycholate assisted method, the enhanced sodium deoxycholate method exhibited superior sensitivity, coverage, and reliability for the identification of membrane proteins particularly those with high hydrophobicity and/or multiple transmembrane domains. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Influence of radiation-induced grafting process on mechanical properties of ETFE-based membranes for fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Ben Youcef, H.; Alkan Guersel, S.; Buisson, A.; Gubler, L.; Wokaun, A.; Scherer, G.G. [Electrochemistry Laboratory, Paul Scherrer Institut, Villigen PSI (Switzerland)

    2010-06-15

    The mechanical stability is, in addition to thermal and chemical stability, a primary requirement of polymer electrolyte membranes in fuel cells. In this study, the impact of grafting parameters and preparation steps on stress-strain properties of ETFE-based proton conducting membranes, prepared by radiation-induced grafting and subsequent sulphonation, was studied. No significant change in the mechanical properties of the ETFE base film was observed below an irradiation dose of 50 kGy. It was shown that the elongation at break decreases with increasing both the crosslinker concentration and graft level (GL). However, the tensile strength was positively affected by the crosslinker concentration. Yield strength and modulus of elasticity are almost unaffected by the introduction of crosslinker. Interestingly, yield strength and modulus of elasticity increase gradually with GL without noticeable change of the inherent crystallinity of grafted films. The most brittle membranes are obtained via the combination of high GL and crosslinker concentration. The optimised ETFE-based membrane (GL of {proportional_to}25%, 5% DVB v/v), shows mechanical properties superior to those of Nafion registered 112 membrane. The obtained results were correlated qualitatively to the other ex situ properties, including crystallinity, thermal properties and water uptake of the grafted membranes. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  11. Synthesis and Characterization of Polycaprolactone-Based Polyurethanes for the Fabrication of Elastic Guided Bone Regeneration Membrane

    Directory of Open Access Journals (Sweden)

    Shyh-Yuan Lee

    2018-01-01

    Full Text Available The aim of this research is to synthesize polycaprolactone-based polyurethanes (PCL-based PUs that can be further used for the fabrication of guided bone regeneration (GBR membranes with higher tensile strength and elongation at break than collagen and PTFE membranes. The PCL-based PUs were prepared by the polymerization of polycaprolactone (PCL diol with 1,6-hexamethylene diisocyanate (HDI at different ratios using either polyethylene glycol (PEG or ethylenediamine (EDA as chain extenders. The chemical, mechanical, and thermal properties of the synthesized polymers were determined using NMR, FTIR, GPC, DSC, and tensile tester. The PCL and polyurethanes were fabricated as nanofiber membranes by electrospinning, and their mechanical properties and SEM morphology were also investigated. In vitro tests, including WST-1 assay, SEM of cells, and phalloidin cytoskeleton staining, were also performed. It was shown that electrospun membranes made of PCL and PCL-HDI-PEG (2 : 3 : 1 possessed tensile strength of 19.84 MPa and 11.72 MPa and elongation at break of 627% and 362%, respectively. These numbers are equivalent or higher than most of the commercially available collagen and PTFE membrane. As a result, these membranes may have potential for future GBR applications.

  12. Porous CS based membranes with improved antimicrobial properties for the treatment of infected wound in veterinary applications

    International Nuclear Information System (INIS)

    Tonda-Turo, C.; Ruini, F.; Argentati, M.; Di Girolamo, N.; Robino, P.; Nebbia, P.; Ciardelli, G.

    2016-01-01

    Recently, much attention has been given to the use of innovative solution for the treatment of infected wounds in animals. Current applied treatments are often un-effective leading to infection propagation and animal death. Novel engineered membranes based on chitosan (CS) can be prepared to combine local antimicrobial effect, high flexibility and easy manipulation. In this work, CS crosslinked porous membranes with improved antimicrobial properties were prepared via freeze-drying technique to promote wound healing and to reduce the bacterial proliferation in infected injuries. Silver nanoparticles (AgNPs) and gentamicin sulfate (GS) were incorporated into the CS matrices to impart antibacterial properties on a wild range of strains. CS based porous membranes were tested for their physicochemical, thermal, mechanical as well as swelling and degradation behavior at physiological condition. Additionally, GS release profile was investigated, showing a moderate burst effect in the first days followed by a decreasing release rate which it was maintained for at least 56 days. Moreover, porous membranes loaded with GS or AgNPs showed good bactericidal activity against both of Gram-positive and Gram-negative bacteria. The bacterial strains used in this work were collected in chelonians after carapace injuries to better mimic the environment after trauma. - Highlights: • Innovative scaffolds for wound healing in veterinary applications • Novel engineered membranes based on chitosan with improved antibacterial properties • Highly flexible and versatile membranes for infected wounds

  13. Porous CS based membranes with improved antimicrobial properties for the treatment of infected wound in veterinary applications

    Energy Technology Data Exchange (ETDEWEB)

    Tonda-Turo, C., E-mail: chiara.tondaturo@polito.it [Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129, Turin (Italy); Ruini, F. [Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129, Turin (Italy); Argentati, M. [Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129, Turin (Italy); Clinic for Exotic Animals, CVS, Via Sandro Giovannini 53, 00137 Rome (Italy); Di Girolamo, N. [Clinic for Exotic Animals, CVS, Via Sandro Giovannini 53, 00137 Rome (Italy); Robino, P.; Nebbia, P. [Department of Veterinary Sciences, University of Turin, Largo Braccini 2, 10095 Grugliasco, Turin (Italy); Ciardelli, G. [Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129, Turin (Italy)

    2016-03-01

    Recently, much attention has been given to the use of innovative solution for the treatment of infected wounds in animals. Current applied treatments are often un-effective leading to infection propagation and animal death. Novel engineered membranes based on chitosan (CS) can be prepared to combine local antimicrobial effect, high flexibility and easy manipulation. In this work, CS crosslinked porous membranes with improved antimicrobial properties were prepared via freeze-drying technique to promote wound healing and to reduce the bacterial proliferation in infected injuries. Silver nanoparticles (AgNPs) and gentamicin sulfate (GS) were incorporated into the CS matrices to impart antibacterial properties on a wild range of strains. CS based porous membranes were tested for their physicochemical, thermal, mechanical as well as swelling and degradation behavior at physiological condition. Additionally, GS release profile was investigated, showing a moderate burst effect in the first days followed by a decreasing release rate which it was maintained for at least 56 days. Moreover, porous membranes loaded with GS or AgNPs showed good bactericidal activity against both of Gram-positive and Gram-negative bacteria. The bacterial strains used in this work were collected in chelonians after carapace injuries to better mimic the environment after trauma. - Highlights: • Innovative scaffolds for wound healing in veterinary applications • Novel engineered membranes based on chitosan with improved antibacterial properties • Highly flexible and versatile membranes for infected wounds.

  14. Preparation and characterization of the PVDF-based composite membrane for direct methanol fuel cells

    OpenAIRE

    Qian Liu, Laizhou Song, Zhihui Zhang, Xiaowei Liu

    2010-01-01

    The polyvinylidene fluoride-sulfonated polystyrene composite membrane with proton exchange performance, denoted as PVDF-SPS, was prepared using a thermally induced polymerization technique. The thermal stability of the PVDF-SPS composite membrane was investigated using thermogravimetric (TG) analysis. The complex formation of the composite membrane was ascertained by Fourier transform infrared spectroscopy (FTIR). The surface compositions of the PVDF-SPS membrane were analyzed using X-ray pho...

  15. Accelerating parameter identification of proton exchange membrane fuel cell model with ranking-based differential evolution

    International Nuclear Information System (INIS)

    Gong, Wenyin; Cai, Zhihua

    2013-01-01

    Parameter identification of PEM (proton exchange membrane) fuel cell model is a very active area of research. Generally, it can be treated as a numerical optimization problem with complex nonlinear and multi-variable features. DE (differential evolution), which has been successfully used in various fields, is a simple yet efficient evolutionary algorithm for global numerical optimization. In this paper, with the objective of accelerating the process of parameter identification of PEM fuel cell models and reducing the necessary computational efforts, we firstly present a generic and simple ranking-based mutation operator for the DE algorithm. Then, the ranking-based mutation operator is incorporated into five highly-competitive DE variants to solve the PEM fuel cell model parameter identification problems. The main contributions of this work are the proposed ranking-based DE variants and their application to the parameter identification problems of PEM fuel cell models. Experiments have been conducted by using both the simulated voltage–current data and the data obtained from the literature to validate the performance of our approach. The results indicate that the ranking-based DE methods provide better results with respect to the solution quality, the convergence rate, and the success rate compared with their corresponding original DE methods. In addition, the voltage–current characteristics obtained by our approach are in good agreement with the original voltage–current curves in all cases. - Highlights: • A simple and generic ranking-based mutation operator is presented in this paper. • Several DE (differential evolution) variants are used to solve the parameter identification of PEMFC (proton exchange membrane fuel cells) model. • Results show that our method accelerates the process of parameter identification. • The V–I characteristics are in very good agreement with experimental data

  16. Measurements of humidified particle number size distributions in a Finnish boreal forest: derivation of hygroscopic particle growth factors

    Energy Technology Data Exchange (ETDEWEB)

    Birmili, W.; Schwirn, K.; Nowak, A.; Rose, D.; Wiedensohler, A. (Leibniz Institute for Tropospheric Research, Leipzig (Germany)); Petaejae, T.; Haemeri, K.; Aalto, P.; Kulmala, M.; Boy, M. (Dept. of Physics, Univ. of Helsinki (Finland)); Joutsensaari, J. (Univ. of Kuopio, Dept. of Physics (Finland))

    2009-07-01

    Dry and humidified size distributions of atmospheric particles were characterised at the atmospheric research station SMEAR 2, Finland between May and July 2004. Particles were classified in a size range between 3 and 800 nm at controlled relative humidities up to 90% by two instruments complementary in size range (HDMPS; Nano-HDMPS). Using the summation method, descriptive hygroscopic growth factors (DHGF) were derived for particle diameters between 70 and 300 nm by comparing dry and humidified size distributions. At 90% relative humidity, DHGF showed mean values between 1.25 and 1.45 in the accumulation mode, between 1.20 and 1.25 in the Aitken mode, and between 1.15 and 1.20 in the nucleation mode. Due to the high size resolution of the method, the transition in DHGF between the Aitken and accumulation modes, which reflects differences in the soluble fraction, could be pinpointed efficiently. For the accumulation mode, experimental DHGFs were compared to those calculated from a simplistic growth model initialised by in-situ chemical composition measurements, and yielded maximum deviations around 0.1. The variation in DHGF could only imperfectly be linked to meteorological factors. A pragmatic parameterisation of DHGF as a function of particle diameter and relative humidity was derived, and subsequently used to study the sensitivity of the condensational sink parameter (CS) as a function of height in a well-mixed boundary layer. (orig.)

  17. Shivering and rewarming after cardiac surgery: comparison of ventilator circuits with humidifier and heated wires to heat and moisture exchangers.

    Science.gov (United States)

    McEvoy, M T; Carey, T J

    1995-07-01

    Detrimental physiologic effects of shivering in the cardiac surgery patient have been well documented. Rewarming techniques have been compared, with noted differences in the incidence of shivering. Ventilator circuits have not been examined independently from other rewarming variables. To compare heated wire humidification circuits with heat and moisture exchanger circuits on the incidence of shivering and speed and pattern of rewarming in mechanically ventilated patients. A prospective, descriptive, correlational study was done on 140 adult cardiac surgery patients in a university teaching medical center. All subjects underwent cardiac surgical procedures with hypothermic cardiopulmonary bypass. Subjects were randomized to humidified, heated wire circuits (n = 70) or heat and moisture exchanger circuits (n = 70). Heated water blankets were used on all patients. Mean intensive care unit admission temperature was 35.28 degrees C. No statistical differences were found in preoperative, demographic, or operative course data between treatment and control groups. Shivering was more common in the heat and moisture exchanger group than in the heated wire group. In our analysis, the only variable associated with shivering was the type of ventilator circuit. Patients using heated wire systems rewarmed more rapidly and had significantly higher temperatures than did patients using heat and moisture exchangers. These data suggest that use of heated wire humidified ventilator circuits with heated water blankets in adult cardiac surgery patients significantly reduces the incidence of shivering and results in a more rapid return to normothermia.

  18. Moisture transfer and pressure drop of humidifying elements made of non-woven fabric (Rayon/PET)

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Nae-Hyun [Incheon National University, Incheon (Korea, Republic of)

    2017-06-15

    In modern buildings, humidity control is an essential constituent of the building management, where spray-type humidifying element is widely used. For the spray-type element, there is a concern about the durability and the resistance to formation of mold. In this study, we made new humidifying elements were made using non-woven fabric rayon/PET and investigated the moisture transfer and pressure drop characteristics. Samples consisted of two different rayon compositions (30 % and 50 %). From the results the sample with 50 % rayon and 50 % PET showed superior moisture transfer performance than the sample with 50 % Kraft fiber and 50 % PET, probably due to better water absorption characteristics of rayon over Kraft fiber. However, pressure drop of the rayon/PET sample was larger than Kraft fiber/PET sample due to increased surface roughness. The moisture transfer performance of the rayon/PET sample deteriorated as the rayon content decreased. The efficiency (j{sub m}/{sup f}1/3) was the largest for rayon/PET (5:5) sample, followed by Kraft fiber/PET and rayon/PET (3:7) sample. The efficiency of commercially available Glasdek was much lower than other samples.

  19. New polymeric electrolyte membranes based on proton donor proton acceptor properties for direct methanol fuel cells

    NARCIS (Netherlands)

    Manea, G.C.; Mulder, M.H.V.

    2002-01-01

    In order to reduce the high methanol permeability of membranes in a direct methanol fuel cell application new and better materials are still required. In this paper membranes made from polybenzimidazole/sulfonated polysulfone are given and compared with homopolymer membranes made from sulfonated

  20. An Adaptable Spectrin/Ankyrin-Based Mechanism for Long-Range Organization of Plasma Membranes in Vertebrate Tissues.

    Science.gov (United States)

    Bennett, Vann; Lorenzo, Damaris N

    2016-01-01

    early axon initial segments and epithelial lateral membranes initially were based on spectrin-ankyrin-cell adhesion molecule assemblies and subsequently served as "incubators," where ion transporters independently acquired ankyrin-binding activity through positive selection. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. Membrane and Films Based on Novel Crown-Containing Dyes as Promising Chemosensoring Materials

    Directory of Open Access Journals (Sweden)

    Sergei Yu. Zaitsev

    2010-12-01

    Full Text Available This paper discusses several works on supramolecular systems such as monolayer and multilayer, polymer films of various crown-containing dyes, surface-active monomers and polymers. Design, production and investigation of the membrane nanostructures based on crown ethers is a rapidly developing field at the “junction” of materials sciences and nanotechnology. These nanostructures can serve as convenient models for studying the self-organization and molecular recognition processes at interfaces that are typical for biomembranes. Based on the results obtained for such structures by absorption and fluorescence spectroscopy, atomic force and Brewster-angle microscopy, surface pressure and surface potential isotherm measurements, the possibility of developing micro- and nanomaterials possessing a set of specified properties (including chemosensor, photochromic and photorefractive materials is demonstrated.

  2. A Glucose Sensor Based on Glucose Oxidase Immobilized by Electrospinning Nanofibrous Polymer Membranes Modified with Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    You Wang

    2013-05-01

    Full Text Available A glucose biosensor based on glucose oxidase immobilized by electrospinning nanofibrous membranes has been developed. Nanofibrous membranes were electrospun from the solution of poly(acrylonitrile-co-acrylic acid containing carbon nanotubes suspension and directly deposited on Pt electrodes for immobilizing glucose oxidase. The morphologies and structure of the nanofibrous membranes with or without carbon nanotubes were characterized by scanning electron microscopy. The fabrication parameters of nanofibers were optimized such as thickness of the nanofibrous membranes and mass ration of carbon nanotubes. The biosensor showed the relationship with a concentration range of 0.1–10 mM and response time was 60 s. The sensitivity of carbon nanotubes modified biosensors was two times larger than which of no carbon nanotubes modified ones. The pH effect, interference and lifetime of biosensors were discussed.

  3. Water flow in carbon-based nanoporous membranes impacted by interactions between hydrated ions and aromatic rings.

    Science.gov (United States)

    Liu, Jian; Shi, Guosheng; Fang, Haiping

    2017-02-24

    Carbon-based nanoporous membranes, such as carbon nanotubes (CNTs), graphene/graphene oxide and graphyne, have shown great potential in water desalination and purification, gas and ion separation, biosensors, and lithium-based batteries, etc. A deep understanding of the interaction between hydrated ions in an aqueous solution and the graphitic surface in systems composed of water, ions and a graphitic surface is essential for applications with carbon-based nanoporous membrane platforms. In this review, we describe the recent progress of the interaction between hydrated ions and aromatic ring structures on the carbon-based surface and its applications in the water flow in a carbon nanotube. We expect that these works can be extended to the understanding of water flow in other nanoporous membranes, such as nanoporous graphene, graphyne and stacked sheets of graphene oxide.

  4. Comparative Study of One-Step Cross-Linked Electrospun Chitosan-Based Membranes

    Directory of Open Access Journals (Sweden)

    Yanet E. Aguirre-Chagala

    2017-01-01

    Full Text Available Chitosan membranes are widely applied for tissue engineering; however, a major drawback is their low resistance in aqueous phases and therefore the structure collapses impeding their long-term use. Although there is extensive research, because of chitosan’s importance as a biomaterial, studies involving chitosan-based membranes are still needed. Herein, a detailed investigation of diverse chemical routes to cross-link fibers in situ by electrospinning process is described. In case of using genipin as cross-linker, a close relationship with the content and the mean diameter values is reported, suggesting a crucial effect over the design of nanostructures. Also, the physical resistance is enhanced for the combination of two types of methods, such as chemical and physical methods. Cross-linked fibers upon exposure to long wave ultraviolet A (UVA light change their morphology, but not their chemical composition. When they are incubated in aqueous phase for 70 days, they show an extensive improvement of their macrostructural integrity which makes them attractive candidates for tissue engineering application. As a result, the thermal properties of these materials reveal less crystallinity and higher temperature of degradation.

  5. Simulation of flux during electro-membrane extraction based on the Nernst-Planck equation.

    Science.gov (United States)

    Gjelstad, Astrid; Rasmussen, Knut Einar; Pedersen-Bjergaard, Stig

    2007-12-07

    The present work has for the first time described and verified a theoretical model of the analytical extraction process electro-membrane extraction (EME), where target analytes are extracted from an aqueous sample, through a thin layer of 2-nitrophenyl octylether immobilized as a supported liquid membrane (SLM) in the pores in the wall of a porous hollow fibre, and into an acceptor solution present inside the lumen of the hollow fibre by the application of an electrical potential difference. The mathematical model was based on the Nernst-Planck equation, and described the flux over the SLM. The model demonstrated that the magnitude of the electrical potential difference, the ion balance of the system, and the absolute temperature influenced the flux of analyte across the SLM. These conclusions were verified by experimental data with five basic drugs. The flux was strongly dependent of the potential difference over the SLM, and increased potential difference resulted in an increase in the flux. The ion balance, defined as the sum of ions in the donor solution divided by the sum of ions in the acceptor solution, was shown to influence the flux, and high ionic concentration in the acceptor solution relative to the sample solution was advantageous for high flux. Different temperatures also led to changes in the flux in the EME system.

  6. Oxygen transport membrane reactor based method and system for generating electric power

    Science.gov (United States)

    Kelly, Sean M.; Chakravarti, Shrikar; Li, Juan

    2017-02-07

    A carbon capture enabled system and method for generating electric power and/or fuel from methane containing sources using oxygen transport membranes by first converting the methane containing feed gas into a high pressure synthesis gas. Then, in one configuration the synthesis gas is combusted in oxy-combustion mode in oxygen transport membranes based boiler reactor operating at a pressure at least twice that of ambient pressure and the heat generated heats steam in thermally coupled steam generation tubes within the boiler reactor; the steam is expanded in steam turbine to generate power; and the carbon dioxide rich effluent leaving the boiler reactor is processed to isolate carbon. In another configuration the synthesis gas is further treated in a gas conditioning system configured for carbon capture in a pre-combustion mode using water gas shift reactors and acid gas removal units to produce hydrogen or hydrogen-rich fuel gas that fuels an integrated gas turbine and steam turbine system to generate power. The disclosed method and system can also be adapted to integrate with coal gasification systems to produce power from both coal and methane containing sources with greater than 90% carbon isolation.

  7. Lanthanum(IlI) PVC membrane electrodes based on 1,3,5-trithiacyclohexane.

    Science.gov (United States)

    Shamsipur, Mojtaba; Yousefi, Mohammad; Hosseini, Morteza; Ganjali, Mohammad Reza

    2002-11-01

    Novel plasticized polymeric membrane (PPME) and membrane-coated graphite (MCGE) electrodes based on 1,3,5-trithiacyclohexane for highly selective determination of La3+ ion have been developed. The electrodes exhibit Nernstian responses over very wide concentration ranges (8.0 x 10(-6)-5.0 x 10(-2) M for PPME and 4.0 x 10(-8)-1.0 x 10(-2) M for MCGE). The limit of detections were 5.0 x 10(-6) and 2.0 x 10(-8) M for PPME and MCGE, respectively. The electrodes possess a fast response time of approximately 10 s and can be used for at least 6 months without observing any deviation. The proposed electrodes revealed excellent selectivities for La3+ over a wide variety of alkali, alkaline earth, transition, and heavy metal ions and could be used in a pH range of 5.0-8.0. The practical utility of the electrodes has been demonstrated by their use as indicator electrodes in the potentiometric titration of La3+ ions with EDTA and in determination of F- in some mouthwash preparations.

  8. A New Emulsion Liquid Membrane Based on a Palm Oil for the Extraction of Heavy Metals

    Directory of Open Access Journals (Sweden)

    Sanna Björkegren

    2015-04-01

    Full Text Available The extraction efficiency of hexavalent chromium, Cr(VI, from water has been investigated using a vegetable oil based emulsion liquid membrane (ELM technique. The main purpose of this study was to create a novel ELM formulation by choosing a more environmentally friendly and non-toxic diluent such as palm oil. The membrane phase so formulated includes the mobile carrier tri-n-octylmethylammonium chloride (TOMAC, to facilitate the metal transport, and the hydrophilic surfactant Tween 80 to facilitate the dispersion of the ELM phase in the aqueous solution. Span 80 is used as surfactant and butanol as co-surfactant. Our results demonstrate that this novel ELM formulation, using the vegetable palm oil as diluent, is useful for the removal of hexavalent chromium with an efficiency of over 99% and is thus competitive with the already existing, yet less environmentally friendly, ELM formulations. This result was achieved with an optimal concentration of 0.1 M NaOH as stripping agent and an external phase pH of 0.5. Different water qualities have also been investigated showing that the type of water (deionized, distilled, or tap water does not significantly influence the extraction rate.

  9. Reaction-sintered porous mineral-based mullite ceramic membrane supports made from recycled materials.

    Science.gov (United States)

    Dong, Yingchao; Zhou, Jian-Er; Lin, Bin; Wang, Yongqing; Wang, Songlin; Miao, Lifeng; Lang, Ying; Liu, Xingqin; Meng, Guangyao

    2009-12-15

    Bulk porous mullite supports for ceramic membranes were prepared directly using a mixture of industrial waste fly ash and bauxite by dry-pressing, followed by sintering between 1200 and 1550 degrees C. The effects of sintering temperature on the phase composition and shrinkage percent of porous mullite were studied. The XRD results indicate that secondary mullitization reaction took place above 1200 degrees C, and completed at 1450 degrees C. During sintering, the mixture samples first shrunk, then expanded abnormally between 1326 and 1477 degrees C, and finally shrunk again above 1477 degrees C. This unique volume self-expansion is ascribed to the secondary mullitization reaction between bauxite and fly ash. More especially, the micro-structural variations induced by this self-expansion sintering were verified by SEM, porosity, pore size distribution and nitrogen gas permeation flux. During self-expansion sintering, with increasing temperature, an abnormal increase in both open porosity and pore size is observed, which also results in the increase of nitrogen gas flux. The mineral-based mullite supports with increased open porosity were obtained. Furthermore, the sintered porous mullite membrane supports were characterized in terms of thermal expansion co-efficient and mechanical strength.

  10. Strontium PVC-membrane sensor based on 2-[(2-mercaptophenylimino)methyl]phenol

    Energy Technology Data Exchange (ETDEWEB)

    Zamani, Hassan Ali [Young Researchers Club, Quchan branch, Islamic Azad University, Quchan (Iran, Islamic Republic of)], E-mail: haszamani@yahoo.com; Ganjali, Mohammad Reza; Norouzi, Parviz [Center of Excellence in Electrochemistry, Faculty of Chemistry, University of Tehran, Tehran (Iran, Islamic Republic of); Endocrine and Metabolism Research Center, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Adib, Mahdi [Center of Excellence in Electrochemistry, Faculty of Chemistry, University of Tehran, Tehran (Iran, Islamic Republic of)

    2008-01-10

    The 2-[(2-mercaptophenylimino)methyl]phenol (MPMP) was used as an excellent ionophore in the construction of a Sr{sup 2+} PVC-based membrane sensor. The best performance was obtained with a membrane composition of 30% poly(vinyl chloride), 62% nitrobenzen (NB), 5.5% MPMP and 2.5% sodium tetraphenyl borate (NaTBP). This sensor demonstrates a good selectivity and sensitivity towards the strontium ion for many cations, including alkali, alkaline earth, transition and heavy metal ions. The sensor revealed a great enhancement in selectivity coefficients for strontium ions in comparison with the previously reported strontium sensors. The proposed sensor exhibits a Nernstian behavior (with a slope of 29.6 {+-} 0.3 mV per decade) for the concentration range of (1.0 x 10{sup -6}-1.0 x 10{sup -1} M) with a detection limit of 5.5 x 10{sup -7} M (48.2 ng/mL). It illustrates a relatively fast response time in the whole concentration range (< 10 s) and it can be used for at least 10 weeks in a pH range of 2.8-9.6. The developed sensor was successfully used as an indicator electrode in the Sr(II) titration with EDTA and the Sr{sup 2+} ion recovery from binary mixtures.

  11. RED WINE EXTRACT OBTAINED BY MEMBRANE-BASED SUPERCRITICAL FLUID EXTRACTION: PRELIMINARY CHARACTERIZATION OF CHEMICAL PROPERTIES.

    Directory of Open Access Journals (Sweden)

    W. Silva

    Full Text Available ABSTRACT This study aims to obtain an extract from red wine by using membrane-based supercritical fluid extraction. This technique involves the use of porous membranes as contactors during the dense gas extraction process from liquid matrices. In this work, a Cabernet Sauvignon wine extract was obtained from supercritical fluid extraction using pressurized carbon dioxide as solvent and a hollow fiber contactor as extraction setup. The process was continuously conducted at pressures between 12 and 18 MPa and temperatures ranged from 30 to 50ºC. Meanwhile, flow rates of feed wine and supercritical CO2 varied from 0.1 to 0.5 mL min-1 and from 60 to 80 mL min-1 (NCPT, respectively. From extraction assays, the highest extraction percentage value obtained from the total amount of phenolic compounds was 14% in only one extraction step at 18MPa and 35ºC. A summarized chemical characterization of the obtained extract is reported in this work; one of the main compounds in this extract could be a low molecular weight organic acid with aromatic structure and methyl and carboxyl groups. Finally, this preliminary characterization of this extract shows a remarkable ORAC value equal to 101737 ± 5324 µmol Trolox equivalents (TE per 100 g of extract.

  12. Model for capping of membrane receptors based on boundary surface effects

    Science.gov (United States)

    Gershon, N. D.

    1978-01-01

    Crosslinking of membrane surface receptors may lead to their segregation into patches and then into a single large aggregate at one pole of the cell. This process is called capping. Here, a novel explanation of such a process is presented in which the membrane is viewed as a supersaturated solution of receptors in the lipid bilayer and the adjacent two aqueous layers. Without a crosslinking agent, a patch of receptors that is less than a certain size cannot stay in equilibrium with the solution and thus should dissolve. Patches greater than a certain size are stable and can, in principle, grow by the precipitation of the remaining dissolved receptors from the supersaturated solution. The task of the crosslinking molecules is to form such stable patches. These considerations are based on a qualitative thermodynamic calculation that takes into account the existence of a boundary tension in a patch (in analogy to the surface tension of a droplet). Thermodynamically, these systems should cap spontaneously after the patches have reached a certain size. But, in practice, such a process can be very slow. A suspension of patches may stay practically stable. The ways in which a cell may abolish this metastable equilibrium and thus achieve capping are considered and possible effects of capping inhibitors are discussed. PMID:274724

  13. The Effect of Reactive Ionic Liquid or Plasticizer Incorporation on the Physicochemical and Transport Properties of Cellulose Acetate Propionate-Based Membranes

    Directory of Open Access Journals (Sweden)

    Edyta Rynkowska

    2018-01-01

    Full Text Available Pervaporation is a membrane-separation technique which uses polymeric and/or ceramic membranes. In the case of pervaporation processes applied to dehydration, the membrane should transport water molecules preferentially. Reactive ionic liquid (RIL (3-(1,3-diethoxy-1,3-dioxopropan-2-yl-1-methyl-1H-imidazol-3-ium was used to prepare novel dense cellulose acetate propionate (CAP based membranes, applying the phase-inversion method. The designed polymer-ionic liquid system contained ionic liquid partially linked to the polymeric structure via the transesterification reaction. The various physicochemical, mechanical, equilibrium and transport properties of CAP-RIL membranes were determined and compared with the properties of CAP membranes modified with plasticizers, i.e., tributyl citrate (TBC and acetyl tributyl citrate (ATBC. Thermogravimetric analysis (TGA testified that CAP-RIL membranes as well as CAP membranes modified with TBC and ATBC are thermally stable up to at least 120 °C. Tensile tests of the membranes revealed improved mechanical properties reflected by reduced brittleness and increased elongation at break achieved for CAP-RIL membranes in contrast to pristine CAP membranes. RIL plasticizes the CAP matrix, and CAP-RIL membranes possess preferable mechanical properties in comparison to membranes with other plasticizers investigated. The incorporation of RIL into CAP membranes tuned the surface properties of the membranes, enhancing their hydrophilic character. Moreover, the addition of RIL into CAP resulted in an excellent improvement of the separation factor, in comparison to pristine CAP membranes, in pervaporation dehydration of propan-2-ol. The separation factor β increased from ca. 10 for pristine CAP membrane to ca. 380 for CAP-16.7-RIL membranes contacting an azeotropic composition of water-propan-2-ol mixture (i.e., 12 wt % water.

  14. Novel acid-base hybrid membrane based on amine-functionalized reduced graphene oxide and sulfonated polyimide for vanadium redox flow battery

    International Nuclear Information System (INIS)

    Cao, Li; Sun, Qingqing; Gao, Yahui; Liu, Luntao; Shi, Haifeng

    2015-01-01

    A series of novel acid-base hybrid membranes (SPI/PEI-rGO) based on sulfonated polyimide (SPI) with polyethyleneimine-functionalized reduced graphene oxide (PEI-rGO) are prepared by a solution-casting method for vanadium redox flow battery (VRB). FT-IR and XPS results prove the successful fabrication of PEI-rGO and SPI/PEI-rGO hybrid membranes, which show a dense and homogeneous structure observed by SEM. The physicochemical properties such as water uptake, swelling ratio, ion exchange capacity, proton conductivity and vanadium ion permeability are well controlled by the incorporated PEI-rGO fillers. The interfacial-formed acid-base pairs between PEI-rGO and SPI matrix effectively reduce the swelling ratio and vanadium ion permeability, increasing the stability performance of the hybrid membranes. SPI/PEI-rGO-2 hybrid membrane exhibits a higher coulombic efficiency (CE, 95%) and energy efficiency (EE, 75.6%) at 40 mA cm −2 , as compared with Nafion 117 membrane (CE, 91% and EE, 66.8%). The self-discharge time of the VRB with SPI/PEI-rGO-2 hybrid membrane (80 h) is longer than that of Nafion 117 membrane (26 h), demonstrating the excellent blocking ability for vanadium ion. After 100 charge-discharge cycles, SPI/PEI-rGO-2 membrane exhibits the good stability under strong oxidizing and acid condition, proving that SPI/PEI-rGO acid-base hybrid membranes could be used as the promising candidates for VRB applications

  15. Inorganic-based proton conductive composite membranes for elevated temperature and reduced relative humidity PEM fuel cells

    Science.gov (United States)

    Wang, Chunmei

    Proton exchange membrane (PEM) fuel cells are regarded as highly promising energy conversion systems for future transportation and stationary power generation and have been under intensive investigations for the last decade. Unfortunately, cutting edge PEM fuel cell design and components still do not allow economically commercial implementation of this technology. The main obstacles are high cost of proton conductive membranes, low-proton conductivity at low relative humidity (RH), and dehydration and degradation of polymer membranes at high temperatures. The objective of this study was to develop a systematic approach to design a high proton conductive composite membrane that can provide a conductivity of approximately 100 mS cm-1 under hot and dry conditions (120°C and 50% RH). The approach was based on fundamental and experimental studies of the proton conductivity of inorganic additives and composite membranes. We synthesized and investigated a variety of organic-inorganic Nafion-based composite membranes. In particular, we analyzed their fundamental properties, which included thermal stability, morphology, the interaction between inorganic network and Nafion clusters, and the effect of inorganic phase on the membrane conductivity. A wide range of inorganic materials was studied in advance in order to select the proton conductive inorganic additives for composite membranes. We developed a conductivity measurement method, with which the proton conductivity characteristics of solid acid materials, zirconium phosphates, sulfated zirconia (S-ZrO2), phosphosilicate gels, and Santa Barbara Amorphous silica (SBA-15) were discussed in detail. Composite membranes containing Nafion and different amounts of functionalized inorganic additives (sulfated inorganics such as S-ZrO2, SBA-15, Mobil Composition of Matter MCM-41, and S-SiO2, and phosphonated inorganic P-SiO2) were synthesized with different methods. We incorporated inorganic particles within Nafion clusters

  16. Preparation of PES ultrafiltration membranes with natural amino acids based zwitterionic antifouling surfaces

    International Nuclear Information System (INIS)

    Xu, Chen; Liu, Xiaojiu; Xie, Binbin; Yao, Chen; Hu, Wenhan; Li, Yi; Li, Xinsong

    2016-01-01

    Highlights: • Amino acids have been successfully grafted onto the surface of PES membranes via amino groups induced epoxy ring opening. • Zwitterionic PES ultrafiltration membranes exhibit excellent antifouling performance and improved permeation properties. • A facile strategy to combat fouling of PES ultrafiltration membranes is developed by grafting natural amino acids. - Abstract: In this report, a simple and facile approach to enhance the antifouling property of poly(ether sulfone) (PES) ultrafiltration membrane was developed by grafting natural amino acids onto surface. First of all, poly(ether sulfone) composite membranes blended with poly(glycidyl methacrylate) were fabricated by phase inversion method followed by grafting of different types of natural amino acids onto the membrane surface through epoxy ring opening reaction. The analysis of attenuated total reflectance Fourier transform infrared spectroscopy (ATR/FTIR) and X-ray photoelectron spectroscopy (XPS) verified the substantial enrichment of amino acids onto the surface of PES membranes. The hydrophilicity of the PES membranes was improved after grafting amino acids. The mechanical property and morphologies of the PES membranes proved that their basic performances were not obviously affected by grafting reaction, and these parameters were all still in the typical range for ultrafiltration membranes. The antifouling property of the grafted PES membranes against bovine serum albumin (BSA) and lysozyme (Lyz) was investigated in detail. It was found that PES membranes incorporated with neutral amino acids exhibited higher fouling resistance to both BSA and Lyz than the parent PES membrane. It can be ascribed to the formation of zwitterionic structure on the surface consisting of protonated secondary amino cations and carboxyl anions. Meanwhile, PES membranes grafted with charged amino acids had better antifouling properties against protein with same electric charges and improved adsorption

  17. Preparation of PES ultrafiltration membranes with natural amino acids based zwitterionic antifouling surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Chen; Liu, Xiaojiu; Xie, Binbin; Yao, Chen [School of Chemistry and Chemical Engineering, Southeast University, Nanjing, 211189 (China); Hu, Wenhan; Li, Yi [Suzhou Faith & Hope Membrane Technology Co., Ltd., Suzhou, 215000 (China); Li, Xinsong, E-mail: lixs@seu.edu.cn [School of Chemistry and Chemical Engineering, Southeast University, Nanjing, 211189 (China)

    2016-11-01

    Highlights: • Amino acids have been successfully grafted onto the surface of PES membranes via amino groups induced epoxy ring opening. • Zwitterionic PES ultrafiltration membranes exhibit excellent antifouling performance and improved permeation properties. • A facile strategy to combat fouling of PES ultrafiltration membranes is developed by grafting natural amino acids. - Abstract: In this report, a simple and facile approach to enhance the antifouling property of poly(ether sulfone) (PES) ultrafiltration membrane was developed by grafting natural amino acids onto surface. First of all, poly(ether sulfone) composite membranes blended with poly(glycidyl methacrylate) were fabricated by phase inversion method followed by grafting of different types of natural amino acids onto the membrane surface through epoxy ring opening reaction. The analysis of attenuated total reflectance Fourier transform infrared spectroscopy (ATR/FTIR) and X-ray photoelectron spectroscopy (XPS) verified the substantial enrichment of amino acids onto the surface of PES membranes. The hydrophilicity of the PES membranes was improved after grafting amino acids. The mechanical property and morphologies of the PES membranes proved that their basic performances were not obviously affected by grafting reaction, and these parameters were all still in the typical range for ultrafiltration membranes. The antifouling property of the grafted PES membranes against bovine serum albumin (BSA) and lysozyme (Lyz) was investigated in detail. It was found that PES membranes incorporated with neutral amino acids exhibited higher fouling resistance to both BSA and Lyz than the parent PES membrane. It can be ascribed to the formation of zwitterionic structure on the surface consisting of protonated secondary amino cations and carboxyl anions. Meanwhile, PES membranes grafted with charged amino acids had better antifouling properties against protein with same electric charges and improved adsorption

  18. Preparation, characterization, biological activity, and transport study of polystyrene based calcium–barium phosphate composite membrane

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Mohammad Mujahid Ali; Rafiuddin,, E-mail: rafi_amu@rediffmail.com

    2013-10-15

    Calcium–barium phosphate (CBP) composite membrane with 25% polystyrene was prepared by co-precipitation method. Scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transformed infrared (FTIR), and Thermogravimetric analysis (TGA) were used to characterize the membrane. The membrane was found to be crystalline in nature with consistent arrangement of particles and no indication of visible cracks. The electrical potentials measured across the composite membrane in contact with univalent electrolytes (KCl, NaCl and LiCl), have been found to increase with decrease in concentrations. Thus the membrane was found to be cation-selective. Transport properties of developed membranes may be utilized for the efficient desalination of saline water and more importantly demineralization process. The antibacterial study of this composite membrane shows good results for killing the disease causing bacteria along with waste water treatment. Highlights: • Transport properties of composite membrane are evaluated. • The composite membrane was found to be stable in all media. • TMS method is used for electrochemical characterization. • The membrane was found to be cation selective. • The order of surface charge density was found to be LiCl < NaCl < KCl.

  19. Diffusion mediated coagulation and fragmentation based study of domain formation in lipid bilayer membrane

    Energy Technology Data Exchange (ETDEWEB)

    Rao, Laxminarsimha V., E-mail: laxman@iitk.ac.in [Mechanics and Applied Mathematics Group, Department of Mechanical Engineering, Indian Institute of Technology Kanpur, Kanpur 208016 (India); Roy, Subhradeep [Department of Biomedical Engineering and Mechanics (MC 0219), Virginia Tech, 495 Old Turner Street, Blacksburg, VA 24061 (United States); Das, Sovan Lal [Mechanics and Applied Mathematics Group, Department of Mechanical Engineering, Indian Institute of Technology Kanpur, Kanpur 208016 (India)

    2017-01-15

    We estimate the equilibrium size distribution of cholesterol rich micro-domains on a lipid bilayer by solving Smoluchowski equation for coagulation and fragmentation. Towards this aim, we first derive the coagulation kernels based on the diffusion behaviour of domains moving in a two dimensional membrane sheet, as this represents the reality better. We incorporate three different diffusion scenarios of domain diffusion into our coagulation kernel. Subsequently, we investigate the influence of the parameters in our model on the coagulation and fragmentation behaviour. The observed behaviours of the coagulation and fragmentation kernels are also manifested in the equilibrium domain size distribution and its first moment. Finally, considering the liquid domains diffusing in a supported lipid bilayer, we fit the equilibrium domain size distribution to a benchmark solution.

  20. Comparative Experimental Study on Ionic Polymer Mental Composite based on Nafion and Aquivion Membrane as Actuators

    Science.gov (United States)

    Luo, B.; Chen, Z.

    2017-11-01

    Most ionic polymer mental composites employ Nafion as the polymer matrix, Aquivion can also manufactured as ionic polymer mental composite while research was little. This paper researched on two kinds of ionic polymer mental composite based on Aquivion and Nafion matrix with palladium electrode called Aquivion-IPMC and Nafion-IPMC. The samples were fabricated by the same preparation process. The current and deformation responses of the samples were measured at voltage to characterize the mechano-electrical properties. The experimental observations revealed that shorter flexible side chains in Aquivion-IPMC provide a larger force than Nafion-IPMC, while the displacement properties were similar in two different samples. The results also showed that Aquivion membrane can also replace Nafion to reproduce IPMC application in soft robots, MEMS, and so on.

  1. Real time optimization of solar powered direct contact membrane distillation based on multivariable extremum seeking

    KAUST Repository

    Karam, Ayman M.; Laleg-Kirati, Taous-Meriem

    2015-01-01

    This paper presents a real time optimization scheme for a solar powered direct contact membrane distillation (DCMD) water desalination system. The sun and weather conditions vary and are inconsistent throughout the day. Therefore, the solar powered DCMD feed inlet temperature is never constant, which influences the distilled water flux. The problem of DCMD process optimization has not been studied enough. In this work, the response of the process under various feed inlet temperatures is investigated, which demonstrates the need for an optimal controller. To address this issue, we propose a multivariable Newton-based extremum seeking controller which optimizes the inlet feed and permeate mass flow rates as the feed inlet temperature varies. Results are presented and discussed for a realistic temperature profile.

  2. Optimization of a bolometer detector for ITER based on Pt absorber on SiN membrane

    Energy Technology Data Exchange (ETDEWEB)

    Meister, H.; Eich, T.; Endstrasser, N.; Giannone, L.; Kannamueller, M.; Kling, A.; Koll, J.; Trautmann, T. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, Boltzmannstr. 2, D-85748 Garching (Germany); Detemple, P.; Schmitt, S. [Institut fuer Mikrotechnik Mainz GmbH, Carl-Zeiss-Str. 18-20, D-55129 Mainz (Germany); Collaboration: ASDEX Upgrade Team

    2010-10-15

    Any plasma diagnostic in ITER must be able to operate at temperatures in excess of 200 deg. C and neutron loads corresponding to 0.1 dpa over its lifetime. To achieve this aim for the bolometer diagnostic, a miniaturized metal resistor bolometer detector based on Pt absorbers galvanically deposited on SiN membranes is being developed. The first two generations of detectors featured up to 4.5 {mu}m thick absorbers. Results from laboratory tests are presented characterizing the dependence of their calibration constants under thermal loads up to 450 deg. C. Several detectors have been tested in ASDEX Upgrade providing reliable data but also pointing out the need for further optimization. A laser trimming procedure has been implemented to reduce the mismatch in meander resistances below 1% for one detector and the thermal drifts from this mismatch.

  3. A superhydrophobic chip based on SU-8 photoresist pillars suspended on a silicon nitride membrane

    KAUST Repository

    Marinaro, Giovanni; Accardo, Angelo; De Angelis, Francesco; Dane, Thomas; Weinhausen, Britta; Burghammer, Manfred; Riekel, Christian

    2014-01-01

    We developed a new generation of superhydrophobic chips optimized for probing ultrasmall sample quantities by X-ray scattering and fluorescence techniques. The chips are based on thin Si3N4 membranes with a tailored pattern of SU-8 photoresist pillars. Indeed, aqueous solution droplets can be evaporated and concentrated at predefined positions using a non-periodic pillar pattern. We demonstrated quantitatively the deposition and aggregation of gold glyconanoparticles from the evaporation of a nanomolar droplet in a small spot by raster X-ray nanofluorescence. Further, raster nanocrystallography of biological objects such as rod-like tobacco mosaic virus nanoparticles reveals crystalline macro-domain formation composed of highly oriented nanorods. © 2014 the Partner Organisations.

  4. A superhydrophobic chip based on SU-8 photoresist pillars suspended on a silicon nitride membrane

    KAUST Repository

    Marinaro, Giovanni

    2014-07-28

    We developed a new generation of superhydrophobic chips optimized for probing ultrasmall sample quantities by X-ray scattering and fluorescence techniques. The chips are based on thin Si3N4 membranes with a tailored pattern of SU-8 photoresist pillars. Indeed, aqueous solution droplets can be evaporated and concentrated at predefined positions using a non-periodic pillar pattern. We demonstrated quantitatively the deposition and aggregation of gold glyconanoparticles from the evaporation of a nanomolar droplet in a small spot by raster X-ray nanofluorescence. Further, raster nanocrystallography of biological objects such as rod-like tobacco mosaic virus nanoparticles reveals crystalline macro-domain formation composed of highly oriented nanorods. © 2014 the Partner Organisations.

  5. Preliminary analysis of a membrane-based atmosphere-control subsystem

    Science.gov (United States)

    Mccray, Scott B.; Newbold, David D.; Ray, Rod; Ogle, Kathryn

    1993-01-01

    Controlled ecological life supprot systems will require subsystems for maintaining the consentrations of atmospheric gases within acceptable ranges in human habitat chambers and plant growth chambers. The goal of this work was to develop a membrane-based atmosphere comntrol (MBAC) subsystem that allows the controlled exchange of atmospheric componets (e.g., oxygen, carbon dioxide, and water vapor) between these chambers. The MBAC subsystem promises to offer a simple, nonenergy intensive method to separate, store and exchange atmospheric components, producing optimal concentrations of components in each chamber. In this paper, the results of a preliminary analysis of the MBAC subsystem for control of oxygen and nitrogen are presented. Additionally, the MBAC subsystem and its operation are described.

  6. A membrane-based subsystem for very high recoveries of spacecraft waste waters

    Science.gov (United States)

    Ray, Roderick J.; Retzlaff, Sandra E.; Radke-Mitchell, Lyn; Newbold, David D.; Price, Donald F.

    1986-01-01

    This paper describes the continued development of a membrane-based subsystem designed to recover up to 99.5 percent of the water from various spacecraft waste waters. Specifically discussed are: (1) the design and fabrication of an energy-efficient reverse-osmosis (RO) breadboard subsystem; (2) data showing the performance of this subsystem when operated on a synthetic wash-water solution - including the results of a 92-day test; and (3) the results of pasteurization studies, including the design and operation of an in-line pasteurizer. Also included in this paper is a discussion of the design and performance of a second RO stage. This second stage results in higher-purity product water at a minimal energy requirement and provides a substantial redundancy factor to this subsystem.

  7. Enantioanalysis of S-deprenyl using enantioselective, potentiometric membrane electrodes based on C60 derivatives

    International Nuclear Information System (INIS)

    Stefan-van Staden, Raluca-Ioana

    2010-01-01

    Enantioselective, potentiometric membrane electrodes based on (1,2-methanofullerene C 60 )-61-carboxylic acid, diethyl (1,2-methanofullerene C 60 )-61-61-dicarboxylate and tert-butyl (1,2-methanofullerene C 60 )-61-carboxylic acid were proposed for the enantioanalysis of S-deprenyl in pharmaceutical compounds. Molecular modeling calculations were performed to prove the reliability of the proposed electrodes. The different characteristics involved in this analysis were explained, namely (i) the stability of each molecule using total energy, hardness and dipole moment, and (ii) the explanation of the mechanism of interaction using intermolecular forces (moderate hydrogen bond interactions), atomic charges and electrostatic potential. Electronic structures as well as molecular interaction have been investigated using Hartree-Fock theory, 3-21G(*) basis set. Stability and feasibility of all the generated structures were supported by their respective energy minima and fundamental frequencies.

  8. Analysis of a membrane-based condesate recovery heat exchanger (CRX)

    Science.gov (United States)

    Newbold, D.D.

    1993-01-01

    The development of a temperature and humidity control system that can remove heat and recover water vapor is key to the development of an Environmental Control and Life Support System (ECLSS). Large quantities of water vapor must be removed from air, and this operation has proven difficult in the absense of gravity. This paper presents the modeling results from a program to develop a novel membrane-based heat exchanger known as the condensate recovery heat exchanger (CRX). This device cools and dehumidifies humid air and simultaneously recovers water-vapor condensate. In this paper, the CRX is described and the results of an analysis of the heat- and mass-transfer characteristics of the device are given.

  9. Performance Degradation Tests of Phosphoric Acid Doped PBI Membrane Based High Temperature PEM Fuel Cells

    DEFF Research Database (Denmark)

    Zhou, Fan; Araya, Samuel Simon; Grigoras, Ionela

    2014-01-01

    Degradation tests of two phosphoric acid (PA) doped PBI membrane based HT-PEM fuel cells were reported in this paper to investigate the effects of start/stop and the presence of methanol in the fuel to the performance degradation. Continuous tests with H2 and simulated reformate which was composed...... of H2, water steam and methanol as the fuel were performed on both single cells. 12-h-startup/12-h-shutdown dynamic tests were performed on the first single cell with pure dry H2 as the fuel and on the second single cell with simulated reformate as the fuel. Along with the tests electrochemical...... techniques such as polarization curves and electrochemical impedance spectroscopy (EIS) were employed to study the degradation mechanisms of the fuel cells. Both single cells showed an increase in the performance in the H2 continuous tests, because of a decrease in the ORR kinetic resistance probably due...

  10. Real time optimization of solar powered direct contact membrane distillation based on multivariable extremum seeking

    KAUST Repository

    Karam, Ayman M.

    2015-09-21

    This paper presents a real time optimization scheme for a solar powered direct contact membrane distillation (DCMD) water desalination system. The sun and weather conditions vary and are inconsistent throughout the day. Therefore, the solar powered DCMD feed inlet temperature is never constant, which influences the distilled water flux. The problem of DCMD process optimization has not been studied enough. In this work, the response of the process under various feed inlet temperatures is investigated, which demonstrates the need for an optimal controller. To address this issue, we propose a multivariable Newton-based extremum seeking controller which optimizes the inlet feed and permeate mass flow rates as the feed inlet temperature varies. Results are presented and discussed for a realistic temperature profile.

  11. Potentiometric determination of trypsin using a polymeric membrane polycation-sensitive electrode based on current-controlled reagent delivery.

    Science.gov (United States)

    Chen, Yan; Ding, Jiawang; Qin, Wei

    2012-12-01

    A potentiometric biosensor for the determination of trypsin is described based on current-controlled reagent delivery. A polymeric membrane protamine-sensitive electrode with dinonylnaphthalene sulfonate as cation exchanger is used for in situ generation of protamine. Diffusion of protamine across the polymeric membrane can be controlled precisely by applying an external current. The hydrolysis catalyzed with trypsin in sample solution decreases the concentration of free protamine released at the sample-membrane interface and facilitates the stripping of protamine out of the membrane surface via the ion-exchange process with sodium ions from the sample solution, thus decreasing the membrane potential, by which the protease can be sensed potentiometrically. The influences of anodic current amplitude, current pulse duration and protamine concentration in the inner filling solution on the membrane potential response have been studied. Under optimum conditions, the proposed protamine-sensitive electrode is useful for continuous and reversible detection of trypsin over the concentration range of 0.5-5UmL(-1) with a detection limit of 0.3UmL(-1). The proposed detection strategy provides a rapid and reagentless way for the detection of protease activities and offers great potential in the homogeneous immunoassays using proteases as labels. Copyright © 2012 Elsevier B.V. All rights reserved.

  12. A Flexible Optical pH Sensor Based on Polysulfone Membranes Coated with pH-Responsive Polyaniline Nanofibers.

    Science.gov (United States)

    Abu-Thabit, Nedal; Umar, Yunusa; Ratemi, Elaref; Ahmad, Ayman; Ahmad Abuilaiwi, Faraj

    2016-06-27

    A new optical pH sensor based on polysulfone (PSU) and polyaniline (PANI) was developed. A transparent and flexible PSU membrane was employed as a support. The electrically conductive and pH-responsive PANI was deposited onto the membrane surface by in situ chemical oxidative polymerization (COP). The absorption spectra of the PANI-coated PSU membranes exhibited sensitivity to pH changes in the range of 4-12, which allowed for designing a dual wavelength pH optical sensor. The performance of the membranes was assessed by measuring their response starting from high pH and going down to low pH, and vice versa. It was found that it is necessary to precondition the sensor layers before each measurement due to the slight hysteresis observed during forward and backward pH titrations. PSU membranes with polyaniline coating thicknesses in the range of ≈100-200 nm exhibited fast response times of pH sensor was characterized by a sigmoidal response (R² = 0.997) which allows for pH determination over a wide dynamic range. All membranes were stable for a period of more than six months when stored in 1 M HCl solution. The reproducibility of the fabricated optical pH sensors was found to be pH sensor was tested and the obtained pH values were compared with the results obtained using a pH meter device.

  13. Characterization of a poly(ether urethane)-based controlled release membrane system for delivery of ketoprofen

    International Nuclear Information System (INIS)

    Macocinschi, Doina; Filip, Daniela; Vlad, Stelian; Oprea, Ana Maria; Gafitanu, Carmen Anatolia

    2012-01-01

    Highlights: ► Ketoprofen incorporation in poly(ether urethane) microporous membrane. ► Moisture sorption properties of as-cast membrane. ► Drug release mechanisms in function of pH and composition of membranes. - Abstract: A poly(ether urethane) based on polytetrahydrofuran containing hydroxypropyl cellulose for biomedical applications was tested for its biocompatibility. Ketoprofen was incorporated (3% and 6%) in the polyurethane matrix as an anti-inflammatory drug. Kinetic and drug release mechanisms were studied. The pore size and pore size distribution of the polyurethane membranes were investigated by scanning electron microscopy. Surface tension characteristics as well as moisture sorption properties such as diffusion coefficients and equilibrium moisture contents of the membrane material were studied. It was found that kinetics and release mechanisms are in function of medium pH, composition of polymer–drug system, pore morphology and pore size distribution. Prolonged nature of release of ketoprofen is assured by low amount of drug in polyurethane membrane and physiological pH.

  14. Cobalt oxide-based catalysts deposited by cold plasma for proton exchange membrane fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Kazimierski, P.; Jozwiak, L.; Sielski, J.; Tyczkowski, J., E-mail: jacek.tyczkowski@p.lodz.pl

    2015-11-02

    In proton exchange membrane fuel cells (PEMFC), both the anodic hydrogen oxidation reaction and the cathodic oxygen reduction reaction (ORR) require appropriate catalysts. So far, platinum-based catalysts are still the best option for this purpose. However, because these catalysts are too expensive for making commercially viable fuel cells, extensive research over the past decade has focused on developing noble metal-free alternative catalysts. In this paper, an approach based on cobalt oxide films fabricated by plasma-enhanced metal-organic chemical vapor deposition is presented. Such a material can be used to prepare catalysts for ORR in PEMFC. The films containing CoO{sub X} were deposited on a carbon paper thereby forming the electrode. Morphology and atomic composition of the films were investigated by scanning electron microscopy and energy-dispersive X-ray spectroscopy, respectively. The possibility of their application as the electro-catalyst for ORR in PEMFC was investigated and the electro-catalytic activities were evaluated by the electrochemical measurements and single cell tests. It was found that the fuel cell with Pt as the anode catalyst and CoO{sub X} deposit as the cathode catalyst was characterized by the open circuit voltage of 635 mV, Tafel slope of approx. 130 mV/dec and the maximum power density of 5.3 W/m{sup 2}. - Highlights: • Cobalt oxide catalyst for proton exchange membrane fuel cells was plasma deposited. • The catalyst exhibits activity for the oxygen reduction reaction. • Morphology and atomic composition of the catalyst were determined.

  15. Membrane-based, sedimentation-assisted plasma separator for point-of-care applications.

    Science.gov (United States)

    Liu, Changchun; Mauk, Michael; Gross, Robert; Bushman, Frederic D; Edelstein, Paul H; Collman, Ronald G; Bau, Haim H

    2013-11-05

    Often, high-sensitivity, point-of-care (POC) clinical tests, such as HIV viral load, require large volumes of plasma. Although centrifuges are ubiquitously used in clinical laboratories to separate plasma from whole blood, centrifugation is generally inappropriate for on-site testing. Suitable alternatives are not readily available to separate the relatively large volumes of plasma from milliliters of blood that may be needed to meet stringent limit-of-detection specifications for low-abundance target molecules. We report on a simple-to-use, low-cost, pump-free, membrane-based, sedimentation-assisted plasma separator capable of separating a relatively large volume of plasma from undiluted whole blood within minutes. This plasma separator consists of an asymmetric, porous, polysulfone membrane housed in a disposable chamber. The separation process takes advantage of both gravitational sedimentation of blood cells and size exclusion-based filtration. The plasma separator demonstrated a "blood in-plasma out" capability, consistently extracting 275 ± 33.5 μL of plasma from 1.8 mL of undiluted whole blood within less than 7 min. The device was used to separate plasma laden with HIV viruses from HIV virus-spiked whole blood with recovery efficiencies of 95.5% ± 3.5%, 88.0% ± 9.5%, and 81.5% ± 12.1% for viral loads of 35,000, 3500, and 350 copies/mL, respectively. The separation process is self-terminating to prevent excessive hemolysis. The HIV-laden plasma was then injected into our custom-made microfluidic chip for nucleic acid testing and was successfully subjected to reverse-transcriptase loop-mediated isothermal amplification (RT-LAMP), demonstrating that the plasma is sufficiently pure to support high-efficiency nucleic acid amplification.

  16. Room-temperature atomic layer deposition of ZrO{sub 2} using tetrakis(ethylmethylamino)zirconium and plasma-excited humidified argon

    Energy Technology Data Exchange (ETDEWEB)

    Kanomata, K. [Graduate School of Science and Engineering, Yamagata University, 4-3-16 Jonan, Yonezawa 992-8510 (Japan); Japan Society for the Promotion of Science, 5-3-1 Kojimachi, Chiyoda-ku, Tokyo 102-0083 (Japan); Tokoro, K.; Imai, T.; Pansila, P.; Miura, M.; Ahmmad, B.; Kubota, S.; Hirahara, K. [Graduate School of Science and Engineering, Yamagata University, 4-3-16 Jonan, Yonezawa 992-8510 (Japan); Hirose, F., E-mail: fhirose@yz.yamagata-u.ac.jp [Graduate School of Science and Engineering, Yamagata University, 4-3-16 Jonan, Yonezawa 992-8510 (Japan)

    2016-11-30

    Highlights: • RT-ALD of ZrO{sub 2} is developed using TEMAZ and plasma-excited humidified argon. • The plasma-excited humidified argon is effective in oxidizing the TEMAZ saturated ZrO{sub 2}. • We discuss the reaction mechanism of the RT-ZrO{sub 2} ALD. - Abstract: Room-temperature atomic layer deposition (ALD) of ZrO{sub 2} is developed with tetrakis(ethylmethylamino)zirconium (TEMAZ) and a plasma-excited humidified argon. A growth per cycle of 0.17 nm/cycle at room temperature is confirmed, and the TEMAZ adsorption and its oxidization on ZrO{sub 2} are characterized by IR absorption spectroscopy with a multiple internal reflection mode. TEMAZ is saturated on a ZrO{sub 2} surface with exposures exceeding ∼2.0 × 10{sup 5} Langmuir (1 Langmuir = 1.0 × 10{sup −6} Torr s) at room temperature, and the plasma-excited humidified argon is effective in oxidizing the TEMAZ-adsorbed ZrO{sub 2} surface. The IR absorption spectroscopy suggests that Zr-OH works as an adsorption site for TEMAZ. The reaction mechanism of room-temperature ZrO{sub 2} ALD is discussed in this paper.

  17. In vivo performance of chitosan/soy-based membranes as wound-dressing devices for acute skin wounds.

    Science.gov (United States)

    Santos, Tírcia C; Höring, Bernhard; Reise, Kathrin; Marques, Alexandra P; Silva, Simone S; Oliveira, Joaquim M; Mano, João F; Castro, António G; Reis, Rui L; van Griensven, Martijn

    2013-04-01

    Wound management represents a major clinical challenge on what concerns healing enhancement and pain control. The selection of an appropriate dressing plays an important role in both recovery and esthetic appearance of the regenerated tissue. Despite the wide range of available dressings, the progress in the wound care market relies on the increasing interest in using natural-based biomedical products. Herein, a rat wound-dressing model of partial-thickness skin wounds was used to study newly developed chitosan/soy (cht/soy)-based membranes as wound-dressing materials. Healing and repair of nondressed, cht/soy membrane-dressed, and Epigard(®)-dressed wounds were followed macroscopically and histologically for 1 and 2 weeks. cht/soy membranes performed better than the controls, promoting a faster wound repair. Re-epithelialization, observed 1 week after wounding, was followed by cornification of the outermost epidermal layer at the second week of dressing, indicating repair of the wounded tissue. The use of this rodent model, although in impaired healing conditions, may enclose some drawbacks regarding the inevitable wound contraction. Moreover, being the main purpose the evaluation of cht/soy-based membranes' performance in the absence of growth factors, the choice of a clinically relevant positive control was limited to a polymeric mesh, without any growth factor influencing skin healing/repair, Epigard. These new cht/soy membranes possess the desired features regarding healing/repair stimulation, ease of handling, and final esthetic appearance-thus, valuable properties for wound dressings.

  18. Hydrogen permeation on Al{sub 2}O{sub 3}-based nickel/cobalt composite membranes

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jihee; Jung, Miewon [Department of Chemistry/Institute of Basic Science, Sungshin Women' s University, Seoul 136-742 (Korea, Republic of); Hong, Tae-Whan [Department of Materials Science and Engineering/Research Center for Sustainable Eco-Devices and Materials(ReSEM), Chungju National University, Chungju 380-702 (Korea, Republic of)

    2010-12-15

    Al{sub 2}O{sub 3} was synthesized using the sol-gel process with aluminum isopropoxide as the precursor and primary distilled water as the solvent. Nickel and cobalt metal powders were used to increase the strength of the membranes. The Al{sub 2}O{sub 3}-based membranes were prepared using HPS following a mechanical alloying process. The phase transformation, thermal evolution, surface and cross-section morphology of Al{sub 2}O{sub 3} and Al{sub 2}O{sub 3}-based membranes were characterized by XRD, TG-DTA and FE-SEM. The hydrogen permeation of Al{sub 2}O{sub 3}-based membranes was examined at 300-473 K under increasing pressure. Hydrogen permeation flux through an Al{sub 2}O{sub 3}-20wt%Co membrane was obtained to 2.36 mol m{sup -2} s{sup -1}. Reaction enthalpy was calculated to 4.5 kJ/mol using a Van't Hoff's plot. (author)

  19. Incorporation of zinc for fabrication of low-cost spinel-based composite ceramic membrane support to achieve its stabilization.

    Science.gov (United States)

    Li, Lingling; Dong, Xinfa; Dong, Yingchao; Zhu, Li; You, Sheng-Jie; Wang, Ya-Fen

    2015-04-28

    In order to reduce environment risk of zinc, a spinel-based porous membrane support was prepared by the high-temperature reaction of zinc and bauxite mineral. The phase evolution process, shrinkage, porosity, mechanical property, pore size distribution, gas permeation flux and microstructure were systematically studied. The XRD results, based on a Zn/Al stoichiometric composition of 1/2, show a formation of ZnAl2O4 structure starting from 1000°C and then accomplished at 1300°C. For spinel-based composite membrane, shrinkage and porosity are mainly influenced by a combination of an expansion induced by ZnAl2O4 formation and a general densification due to amorphous liquid SiO2. The highest porosity, as high as 44%, is observed in ZnAl4 membrane support among all the investigated compositions. Compared with pure bauxite (Al), ZnAl4 composite membrane support is reinforced by ZnAl2O4 phase and inter-locked mullite crystals, which is proved by the empirical strength-porosity relationships. Also, an increase in average pore diameter and gas flux can be observed in ZnAl4. A prolonged leaching experiment reveals the zinc can be successfully incorporated into ceramic membrane support via formation of ZnAl2O4, which has substantially better resistance toward acidic attack. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Colorimetric biomimetic sensor systems based on molecularly imprinted polymer membranes for highly-selective detection of phenol in environmental samples

    Directory of Open Access Journals (Sweden)

    Sergeyeva T. A.

    2014-05-01

    Full Text Available Aim. Development of an easy-to-use colorimetric sensor system for fast and accurate detection of phenol in envi- ronmental samples. Methods. Technique of molecular imprinting, method of in situ polymerization of molecularly imprinted polymer membranes. Results. The proposed sensor is based on free-standing molecularly imprinted polymer (MIP membranes, synthesized by in situ polymerization, and having in their structure artificial binding sites capable of selective phenol recognition. The quantitative detection of phenol, selectively adsorbed by the MIP membranes, is based on its reaction with 4-aminoantipyrine, which gives a pink-colored product. The intensity of staining of the MIP membrane is proportional to phenol concentration in the analyzed sample. Phenol can be detected within the range 50 nM–10 mM with limit of detection 50 nM, which corresponds to the concentrations that have to be detected in natural and waste waters in accordance with environmental protection standards. Stability of the MIP-membrane-based sensors was assessed during 12 months storage at room temperature. Conclusions. The sensor system provides highly-selective and sensitive detection of phenol in both mo- del and real (drinking, natural, and waste water samples. As compared to traditional methods of phenol detection, the proposed system is characterized by simplicity of operation and can be used in non-laboratory conditions.

  1. Experimental elucidation on rate-determining process of water transport in polymer electrolyte fuel cell membrane by magnetic resonance imaging

    International Nuclear Information System (INIS)

    Takita, Shinpei; Tsushima, Shohji; Hirai, Shuichiro; Kubo, Norio; Aotani, Koichiro

    2007-01-01

    We examined rate-determining process of water transport in polymer electrolyte membrane (PEM) used in fuel cells by using magnetic resonance imaging (MRI). We measured transversal water content distributions of the membrane by MRI and through-plane mass flux of water by hygrometers. Through place water flux has taken place in the membrane when relative humidify of supplied gas is not equal in both side of the membrane. MRI results revealed that diffusion coefficient of water in the membrane increases with water content of membrane, λ, whilst it shows intensive peak at λ=3-4. Diffusion resistance and mass transfer resistance involving evaporation and condensation on the interface are almost in the same order and thus water transport process in the membrane is determined by either concentration diffusion or mass transfer, depending on water content of membrane. (author)

  2. Colour-Value Based Method for Polydopamine Coating-Stability Characterization on Polyethersulfone Membranes.

    Science.gov (United States)

    Bucher, Thomas; Clodt, Juliana I; Grabowski, Andrej; Hein, Martin; Filiz, Volkan

    2017-12-16

    Porous polyethersulfone membranes as used in oenology were investigated in order to evaluate temperature-dependent permeances in a temperature range from 10 to 35 °C. A temperature correction factor was determined for this type of membrane to get accurate and comparable results for further developments. Moreover, the membranes were modified with a bio-inspired polydopamine coating in order to reduce fouling. The performance of the membranes could be increased with respect to permeance and flux recovery under cross-flow conditions. In order to test the applicability and stability of the coating layer, they were treated with basic and acidic cleaning agents as used in industry for fouled membranes. The chemical stability of the coating layer was studied under basic and acidic conditions, by systematic observation of the colour change of the coated membranes over treatment time.

  3. Membrane architectures for ion-channel switch-based electrochemical biosensors

    Science.gov (United States)

    Sansinena, Jose-Maria; Redondo, Antonio; Swanson, Basil I.; Yee, Chanel Kitmon; Sapuri/Butti, Annapoorna R.; Parikh, Atul N.; Yang, Calvin

    2008-10-28

    The present invention is directed to a process of forming a bilayer lipid membrane structure by depositing an organic layer having a defined surface area onto an electrically conductive substrate, removing portions of said organic layer upon said electrically conductive substrate whereby selected portions of said organic layer are removed to form defined voids within said defined surface area of said organic layer and defined islands of organic layer upon said electrically conductive substrate, and, depositing a bilayer lipid membrane over the defined voids and defined islands of organic layer upon said substrate whereby aqueous reservoirs are formed between said electrically conductive substrate and said bilayer lipid membrane, said bilayer lipid membrane characterized as spanning across the defined voids between said defined islands. A lipid membrane structure is also described together with an array of such lipid membrane structure.

  4. Highly efficient forward osmosis based on porous membranes--applications and implications.

    Science.gov (United States)

    Qi, Saren; Li, Ye; Zhao, Yang; Li, Weiyi; Tang, Chuyang Y

    2015-04-07

    For the first time, forward osmosis (FO) was performed using a porous membrane with an ultrafiltration (UF)-like rejection layer and its feasibility for high performance FO filtration was demonstrated. Compared to traditional FO membranes with dense rejection layers, the UF-like FO membrane was 2 orders of magnitude more permeable. This gave rise to respectable FO water flux even at ultralow osmotic driving force, for example, 7.6 L/m(2).h at an osmotic pressure of merely 0.11 bar (achieved by using a 0.1% poly(sodium 4-styrene-sulfonate) draw solution). The membrane was applied to oil/water separation, and a highly stable FO water flux was achieved. The adoption of porous FO membranes opens a door to many new opportunities, with potential applications ranging from wastewater treatment, valuable product recovery, and biomedical applications. The potential applications and implications of porous FO membranes are addressed in this paper.

  5. Characteristics of polyimide-based composite membranes fabricated by low-temperature plasma polymerization

    International Nuclear Information System (INIS)

    Dung Thi Tran; Mori, Shinsuke; Suzuki, Masaaki

    2008-01-01

    Composite membranes were prepared by the deposition of plasma-polymerized allylamine films onto a porous polyimide substrate. The relationship between the plasma conditions and the membrane characteristics was described in terms of monomer flow rate, plasma discharge power, plasma polymerization time, and so on. Scanning electron microscope (SEM) images indicate that the thickness of the plasma polymer layer increased and the membrane skin pore size decreased gradually with the increasing of plasma polymerization time. Fourier transform infrared (FTIR) spectra demonstrate the appearance of amine groups in the plasma deposited polymer and the contact angle measurements indicate that the hydrophilicity of the membrane surfaces increased significantly after plasma polymerization. The composite membranes can reject salt from sodium chloride feed solution, and membrane separation performance depends strongly on the plasma conditions applied during the preparation of the plasma deposited polymer films

  6. Identification of Salt-Tolerant Sinorhizobium sp Strain BL3 Membrane Proteins Based on Proteomics

    DEFF Research Database (Denmark)

    Tanthanuch, Waraporn; Mohammed, Shabaz; Matthiesen, Rune

    2010-01-01

    functional categories, the two biggest of which were energy production and conversion, and proteins not in clusters of orthologous groups (COGs). In addition, a comparative analysis of membrane proteins between salt-stressed and non-stressed BL3 cells was conducted using a membrane enrichment method and off-line...... SCX fractionation coupled to nanoLC-MS/MS. These techniques would be useful for further comparative analysis of membrane proteins that function in the response to environmental stress....

  7. Irradiation effects on properties of reverse osmosis membrane based on cross-linked aromatic polyamide

    International Nuclear Information System (INIS)

    Nakase, Yoshiaki; Yanagi, Tadashi; Uemura, Tadahiro.

    1994-01-01

    In order to develop a membrane suitable for reverse osmotic condensation of radioactive liquid wastes, a new cross-linked aromatic polyamide composite reverse osmosis membrane (ROM) was irradiated in water or in wet system, and its mechanical and some thermal properties, and the separation performance for inorganic salt were investigated. A membrane was degraded by irradiation more severely in wet system than in dry system, probably due to the reaction with OH-radicals. In the separation performance for NaCl, the salt rejection of the membrane was kept over 88% until irradiation reached 2MGy, maintaining about 90% of its original water flux. (author)

  8. Radiation-grafted membranes based on polyethylene for direct methanol fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Sherazi, Tauqir A. [Department of Chemistry, Government College University, Lahore 54000 (Pakistan); Institute for Chemical Process and Environmental Technology, National Research Council Canada, 1200 Montreal Road, Ottawa, ON K1A 0R6 (Canada); Guiver, Michael D.; Kingston, David; Xue, Xinzhong [Institute for Chemical Process and Environmental Technology, National Research Council Canada, 1200 Montreal Road, Ottawa, ON K1A 0R6 (Canada); Ahmad, Shujaat [PIEAS/PINSTECH, P O Nilore, Islamabad 45650 (Pakistan); Kashmiri, M. Akram [Department of Chemistry, Government College University, Lahore 54000 (Pakistan); Board of Intermediate and Secondary Education, Lahore 54000 (Pakistan)

    2010-01-01

    Styrene was grafted onto ultrahigh molecular weight polyethylene powder (UHMWPE) by gamma irradiation using a {sup 60}Co source. Compression moulded films of selected pre-irradiated styrene-grafted ultrahigh molecular weight polyethylene (UHMWPE-g-PS) were post-sulfonated to the sulfonic acid derivative (UHMWPE-g-PSSA) for use as proton exchange membranes (PEMs). The sulfonation was confirmed by X-ray photoelectron spectroscopy (XPS). The melting and flow properties of UHMWPE and UHMWPE-g-PS are conducive to forming homogeneous pore-free membranes. Both the ion conductivity and methanol permeability coefficient increased with degree of grafting, but the grafted membranes showed comparable or higher ion conductivity and lower methanol permeability than Nafion {sup registered} 117 membrane. One UHMWPE-g-PS membrane was fabricated into a membrane-electrode assembly (MEA) and tested as a single cell direct methanol fuel cell (DMFC). Low membrane cost and acceptable fuel cell performance indicate that UHMWPE-g-PSSA membranes could offer an alternative approach to perfluorosulfonic acid-type membranes for DMFC. (author)

  9. Effective and highly recyclable ceramic membrane based on amorphous nanosilica for dye removal from t

    Directory of Open Access Journals (Sweden)

    Gehan M.K. Tolba

    2016-03-01

    Full Text Available In this study, an adsorptive ceramic membrane was prepared by a simple dry pressing of a mixture of nanosilica produced from low cost rice husk by hydrothermal technique at sub-critical water conditions, calcium phosphate, and ammonium acetate together and then calcined at 600 °C in air. Optimization of the raw materials ratio was found to be necessary to avoid crack formation during sintering process. The membrane microstructure, dye removal efficiency and the permeation flux of the membranes were investigated. The membrane was tested to remove the methylene blue from aqueous solution. Results show that the removal of the dye increases as the silica content increases in the all given membranes and it decreases with an increase in the ammonium acetate. Moreover, the water flux decreases with an increase in the silica content. The methylene blue adsorbed onto the silica membrane can be removed by calcination and the membrane could be recycled several times without any obvious loss in the adsorption performance. In conclusion, this study demonstrates a convenient strategy to prepare an effective adsorptive membrane, which can be applied as a highly recyclable membrane for the adsorption of organic maters.

  10. A review on polymeric hydrogel membranes for wound dressing applications: PVA-based hydrogel dressings

    Directory of Open Access Journals (Sweden)

    Elbadawy A. Kamoun

    2017-05-01

    Full Text Available This review presents the past and current efforts with a brief description on the featured properties of hydrogel membranes fabricated from biopolymers and synthetic ones for wound dressing applications. Many endeavors have been exerted during past ten years for developing new artificial polymeric membranes, which fulfill the demanded conditions for the treatment of skin wounds. This review mainly focuses on representing specifications of ideal polymeric wound dressing membranes, such as crosslinked hydrogels compatible with wound dressing purposes. But as the hydrogels with single component have low mechanical strength, recent trends have offered composite or hybrid hydrogel membranes to achieve the typical wound dressing requirements.

  11. Fluorescence interference contrast based approach to study real time interaction of melittin with plasma membranes

    Science.gov (United States)

    Gupta, Sharad; Gui, Dong; Zandi, Roya; Gill, Sarjeet; Mohideen, Umar

    2014-03-01

    Melittin is an anti-bacterial and hemolytic toxic peptide found in bee venom. Cell lysis behavior of peptides has been widely investigated, but the exact interaction mechanism of lytic peptides with lipid membranes and its constituents has not been understood completely. In this paper we study the melittin interaction with lipid plasma membranes in real time using non-invasive and non-contact fluorescence interference contrast microscopy (FLIC). Particularly the interaction of melittin with plasma membranes was studied in a controlled molecular environment, where these plasma membrane were composed of saturated lipid, 1,2-diphytanoyl-sn-glycero-3-phosphocholine (DPhPC) and unsaturated lipid, 1,2-dioleoyl-sn-glycero-3-phosphocholine(DOPC) with and without cholesterol. We found out that melittin starts to form nanometer size pores in the plasma membranes shortly after interacting with membranes. But the addition of cholesterol in plasma membrane slows down the pore formation process. Our results show that inclusion of cholesterol to the plasma membranes make them more resilient towards pore formation and lysis of membrane.

  12. A flexible, robust and antifouling asymmetric membrane based on ultra-long ceramic/polymeric fibers for high-efficiency separation of oil/water emulsions.

    Science.gov (United States)

    Wang, Kui; Yiming, Wubulikasimu; Saththasivam, Jayaprakash; Liu, Zhaoyang

    2017-07-06

    Polymeric and ceramic asymmetric membranes have dominated commercial membranes for water treatment. However, polymeric membranes are prone to becoming fouled, while ceramic membranes are mechanically fragile. Here, we report a novel concept to develop asymmetric membranes based on ultra-long ceramic/polymeric fibers, with the combined merits of good mechanical stability, excellent fouling resistance and high oil/water selectivity, in order to meet the stringent requirements for practical oil/water separation. The ultra-long dimensions of ceramic nanofibers/polymeric microfibers endow this novel membrane with mechanical flexibility and robustness, due to the integrated and intertwined structure. This membrane is capable of separating oil/water emulsions with high oil-separation efficiency (99.9%), thanks to its nanoporous selective layer made of ceramic nanofibers. Further, this membrane also displays superior antifouling properties due to its underwater superoleophobicity and ultra-low oil adhesion of the ceramic-based selective layer. This membrane exhibits high water permeation flux (6.8 × 10 4 L m -2 h -1 bar -1 ) at low operation pressures, which is attributed to its 3-dimensional (3D) interconnected fiber-based structure throughout the membrane. In addition, the facile fabrication process and inexpensive materials required for this membrane suggest its significant potential for industrial applications.

  13. Impedimetric DNA Biosensor Based on a Nanoporous Alumina Membrane for the Detection of the Specific Oligonucleotide Sequence of Dengue Virus

    Directory of Open Access Journals (Sweden)

    Chee-Seng Toh

    2013-06-01

    Full Text Available A novel and integrated membrane sensing platform for DNA detection is developed based on an anodic aluminum oxide (AAO membrane. Platinum electrodes (~50–100 nm thick are coated directly on both sides of the alumina membrane to eliminate the solution resistance outside the nanopores. The electrochemical impedance technique is employed to monitor the impedance changes within the nanopores upon DNA binding. Pore resistance (Rp linearly increases in response towards the increasing concentration of the target DNA in the range of 1 × 10−12 to 1 × 10−6 M. Moreover, the biosensor selectively differentiates the complementary sequence from single base mismatched (MM-1 strands and non-complementary strands. This study reveals a simple, selective and sensitive method to fabricate a label-free DNA biosensor.

  14. Impedimetric DNA biosensor based on a nanoporous alumina membrane for the detection of the specific oligonucleotide sequence of dengue virus.

    Science.gov (United States)

    Deng, Jiajia; Toh, Chee-Seng

    2013-06-17

    A novel and integrated membrane sensing platform for DNA detection is developed based on an anodic aluminum oxide (AAO) membrane. Platinum electrodes (~50-100 nm thick) are coated directly on both sides of the alumina membrane to eliminate the solution resistance outside the nanopores. The electrochemical impedance technique is employed to monitor the impedance changes within the nanopores upon DNA binding. Pore resistance (Rp) linearly increases in response towards the increasing concentration of the target DNA in the range of 1 × 10⁻¹² to 1 × 10⁻⁶ M. Moreover, the biosensor selectively differentiates the complementary sequence from single base mismatched (MM-1) strands and non-complementary strands. This study reveals a simple, selective and sensitive method to fabricate a label-free DNA biosensor.

  15. A heat pump driven and hollow fiber membrane-based liquid desiccant air dehumidification system: Modeling and experimental validation

    International Nuclear Information System (INIS)

    Zhang, Li-Zhi; Zhang, Ning

    2014-01-01

    A compression heat pump driven and membrane-based liquid desiccant air dehumidification system is presented. The dehumidifier and the regenerator are made of two hollow fiber membrane bundles packed in two shells. Water vapor can permeate through these membranes effectively, while the liquid desiccant droplets are prevented from cross-over. Simultaneous heating and cooling of the salt solution are realized with a heat pump system to improve energy efficiency. In this research, the system is built up and a complete modeling is performed for the system. Heat and mass transfer processes in the membrane modules, as well as in the evaporator, the condenser, and other key components are modeled in detail. The whole model is validated by experiment. The performances of SDP (specific dehumidification power), dehumidification efficiency, EER (energy efficiency ratio) of heat pump, and the COP (coefficient of performance) of the system are investigated numerically and experimentally. The results show that the model can predict the system accurately. The dehumidification capabilities and the energy efficiencies of the system are high. Further, it performs well even under the harsh hot and humid South China weather conditions. - Highlights: • A membrane-based and heat pump driven air dehumidification system is proposed. • A real experimental set up is built and used to validate the model for the whole system. • Performance under design and varying operation conditions is investigated. • The system performs well even under harsh hot and humid conditions

  16. Crosslinked basement membrane-based coatings enhance glucose sensor function and continuous glucose monitoring in vivo.

    Science.gov (United States)

    Klueh, Ulrike; Ludzinska, Izabela; Czajkowski, Caroline; Qiao, Yi; Kreutzer, Donald L

    2018-01-01

    Overcoming sensor-induced tissue reactions is an essential element of achieving successful continuous glucose monitoring (CGM) in the management of diabetes, particularly when used in closed loop technology. Recently, we demonstrated that basement membrane (BM)-based glucose sensor coatings significantly reduced tissue reactions at sites of device implantation. However, the biocompatible BM-based biohydrogel sensor coating rapidly degraded over a less than a 3-week period, which effectively eliminated the protective sensor coating. In an effort to increase the stability and effectiveness of the BM coating, we evaluated the impact of crosslinking BM utilizing glutaraldehyde as a crosslinking agent, designated as X-Cultrex. Sensor performance (nonrecalibrated) was evaluated for the impact of these X-Cultrex coatings in vitro and in vivo. Sensor performance was assessed over a 28-day time period in a murine CGM model and expressed as mean absolute relative difference (MARD) values. Tissue reactivity of Cultrex-coated, X-Cultrex-coated, and uncoated glucose sensors was evaluated over a 28-day time period in vivo using standard histological techniques. These studies demonstrated that X-Cultrex-based sensor coatings had no effect on glucose sensor function in vitro. In vivo, glucose sensor performance was significantly enhanced following X-Cultrex coating throughout the 28-day study. Histological evaluations of X-Cultrex-treated sensors demonstrated significantly less tissue reactivity when compared to uncoated sensors. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 7-16, 2018. © 2017 Wiley Periodicals, Inc.

  17. Transnasal Humidified Rapid-Insufflation Ventilatory Exchange (THRIVE): a physiological method of increasing apnoea time in patients with difficult airways.

    Science.gov (United States)

    Patel, A; Nouraei, S A R

    2015-03-01

    Emergency and difficult tracheal intubations are hazardous undertakings where successive laryngoscopy-hypoxaemia-re-oxygenation cycles can escalate to airway loss and the 'can't intubate, can't ventilate' scenario. Between 2013 and 2014, we extended the apnoea times of 25 patients with difficult airways who were undergoing general anaesthesia for hypopharyngeal or laryngotracheal surgery. This was achieved through continuous delivery of transnasal high-flow humidified oxygen, initially to provide pre-oxygenation, and continuing as post-oxygenation during intravenous induction of anaesthesia and neuromuscular blockade until a definitive airway was secured. Apnoea time commenced at administration of neuromuscular blockade and ended with commencement of jet ventilation, positive-pressure ventilation or recommencement of spontaneous ventilation. During this time, upper airway patency was maintained with jaw-thrust. Transnasal Humidified Rapid-Insufflation Ventilatory Exchange (THRIVE) was used in 15 males and 10 females. Mean (SD [range]) age at treatment was 49 (15 [25-81]) years. The median (IQR [range]) Mallampati grade was 3 (2-3 [2-4]) and direct laryngoscopy grade was 3 (3-3 [2-4]). There were 12 obese patients and nine patients were stridulous. The median (IQR [range]) apnoea time was 14 (9-19 [5-65]) min. No patient experienced arterial desaturation gaseous exchange through flow-dependent deadspace flushing. It has the potential to transform the practice of anaesthesia by changing the nature of securing a definitive airway in emergency and difficult intubations from a pressured stop-start process to a smooth and unhurried undertaking. © 2014 The Authors Anaesthesia published by John Wiley & Sons Ltd on behalf of Association of Anaesthetists of Great Britain and Ireland.

  18. Non-noble metal based electro-catalyst compositions for proton exchange membrane based water electrolysis and methods of making

    Science.gov (United States)

    Kumta, Prashant N.; Kadakia, Karan Sandeep; Datta, Moni Kanchan; Velikokhatnyi, Oleg

    2017-02-07

    The invention provides electro-catalyst compositions for an anode electrode of a proton exchange membrane-based water electrolysis system. The compositions include a noble metal component selected from the group consisting of iridium oxide, ruthenium oxide, rhenium oxide and mixtures thereof, and a non-noble metal component selected from the group consisting of tantalum oxide, tin oxide, niobium oxide, titanium oxide, tungsten oxide, molybdenum oxide, yttrium oxide, scandium oxide, cooper oxide, zirconium oxide, nickel oxide and mixtures thereof. Further, the non-noble metal component can include a dopant. The dopant can be at least one element selected from Groups III, V, VI and VII of the Periodic Table. The compositions can be prepared using a surfactant approach or a sol gel approach. Further, the compositions are prepared using noble metal and non-noble metal precursors. Furthermore, a thin film containing the compositions can be deposited onto a substrate to form the anode electrode.

  19. Thin film thermocouples for in situ membrane electrode assembly temperature measurements in a polybenzimidazole-based high temperature proton exchange membrane unit cell

    DEFF Research Database (Denmark)

    Ali, Syed Talat; Lebæk, Jesper; Nielsen, Lars Pleth

    2010-01-01

    m thick layer of TFTCs on 75 mu m thick Kapton foil. The Kapton foil was treated with in situ argon plasma etching to improve the adhesion between TFTCs and the Kapton substrate. The TFTCs were covered with a 7 mu m liquid Kapton layer using spin coating technique to protect them from environmental......This paper presents Type-T thin film thermocouples (TFTCs) fabricated on Kapton (polyimide) substrate for measuring the internal temperature of PBI(polybenzimidazole)-based high temperature proton exchange membrane fuel cell (HT-PEMFC). Magnetron sputtering technique was employed to deposit a 2 mu...... degradation. This Kapton foil with deposited TFTCs was used as sealing inside a PBI (polybenzimidazole)-based single cell test rig, which enabled measurements of in situ temperature variations of the working fuel cell MEA. The performance of the TFTCs was promising with minimal interference to the operation...

  20. Aquaporin based biomimetic membrane in forward osmosis: Chemical cleaning resistance and practical operation

    DEFF Research Database (Denmark)

    Li, Zhenyu; Linares, Rodrigo Valladares; Bucs, Szilard

    2017-01-01

    Aquaporin plays a promising role in fabricating high performance biomimetic forward osmosis (FO) membranes. However, aquaporin as a protein also has a risk of denaturation caused, by various chemicals, resulting in a possible decay of membrane performance. The present study tested a novel aquaporin...

  1. Carbon-based building blocks for alcohol dehydration membranes with disorder-enhanced water permeability

    DEFF Research Database (Denmark)

    Boffa, Vittorio; Etmimi, H.; Mallon, P.E.

    2017-01-01

    Graphene oxide (GO) thin films have demonstrated outstanding water permeability and excellent selectivity towards organic molecules and inorganic salts, unlocking a new exciting direction in the development of nanofiltration, desalination and pervaporation membranes. However, there are still high......-HAL membranes promising devices for alcohol dehydration technologies....

  2. Evaluation of a membrane based carbon dioxide absorber for spacecraft ECLS applications

    NARCIS (Netherlands)

    Feron, P.H.M.; Eckhard, F.; Witt, J.

    1996-01-01

    In an on-going harmonized ESA/NIVR project, performed by Stork Comprimo and TNO-MEP, the removal of the carbon dioxide with membranes is studied. The use of membrane gas absorption for carbon dioxide removal is currently hampered by the fact that the commonly used alkanolamines result in leakage

  3. Aquaporin based biomimetic membrane in forward osmosis: Chemical cleaning resistance and practical operation

    DEFF Research Database (Denmark)

    Li, Zhenyu; Linares, Rodrigo Valladares; Bucs, Szilard

    2017-01-01

    Aquaporin plays a promising role in fabricating high performance biomimetic forward osmosis (FO) membranes. However, aquaporin as a protein also has a risk of denaturation caused, by various chemicals, resulting in a possible decay of membrane performance. The present study tested a novel aquapor...

  4. Nanofiltration membranes based on polyvinylidene fluoride nanofibrous scaffolds and crosslinked polyethyleneimine networks

    Energy Technology Data Exchange (ETDEWEB)

    Park, Seong-Jik [Hankyong National University, Department of Bioresources and Rural Systems Engineering (Korea, Republic of); Cheedrala, Ravi Kumar; Diallo, Mamadou S., E-mail: mdiallo@kaist.ac.kr [Korea Advanced Institute of Science and Technology (KAIST), Graduate School of Energy, Environment, Water and Sustainability (EEWS) (Korea, Republic of); Kim, Changmin; Kim, In S. [Gwangju Institute of Science and Technology (GIST), Department of Environmental Science and Engineering (Korea, Republic of); Goddard, William A. [Korea Advanced Institute of Science and Technology (KAIST), Graduate School of Energy, Environment, Water and Sustainability (EEWS) (Korea, Republic of)

    2012-07-15

    In this article, we describe the synthesis of new and ion-selective nanofiltration (NF) membranes using polyvinylidene fluoride (PVDF) nanofibers and hyperbranched polyethylenimine (PEI) as building blocks. These new nanofibrous composite (NFC) membranes consist of crosslinked hyperbranched PEI networks supported by PVDF nanofibrous scaffolds that are electrospun onto commercial PVDF microfiltration (MF) membranes. A major objective of our study was to fabricate positively charged NF membranes that can be operated at low pressure with high water flux and improved rejection for monovalent cations. To achieve this, we investigated the effects of crosslinker chemistry on membrane properties (morphology, composition, hydrophobicity, and zeta potential) and membrane performance (salt rejection and permeate flux) in aqueous solutions (2,000 mg/L) of four salts (NaCl, MgCl{sub 2}, Na{sub 2}SO{sub 4}, and MgSO{sub 4}) at pH 4, 6, and 8. We found that an NFC-PVDF membrane with a network of PEI macromolecules crosslinked with trimesoyl chloride has a high water flux ({approx}30 L m{sup -2} h{sup -1}) and high rejections for MgCl{sub 2} ({approx}88 %) and NaCl ({approx}65 %) at pH 6 using a pressure of 7 bar. The overall results of our study suggest that PVDF nanofibers and hyperbranched PEI are promising building blocks for the fabrication of high performance NF membranes for water purification.

  5. Nanofiltration membranes based on polyvinylidene fluoride nanofibrous scaffolds and crosslinked polyethyleneimine networks

    International Nuclear Information System (INIS)

    Park, Seong-Jik; Cheedrala, Ravi Kumar; Diallo, Mamadou S.; Kim, Changmin; Kim, In S.; Goddard, William A.

    2012-01-01

    In this article, we describe the synthesis of new and ion-selective nanofiltration (NF) membranes using polyvinylidene fluoride (PVDF) nanofibers and hyperbranched polyethylenimine (PEI) as building blocks. These new nanofibrous composite (NFC) membranes consist of crosslinked hyperbranched PEI networks supported by PVDF nanofibrous scaffolds that are electrospun onto commercial PVDF microfiltration (MF) membranes. A major objective of our study was to fabricate positively charged NF membranes that can be operated at low pressure with high water flux and improved rejection for monovalent cations. To achieve this, we investigated the effects of crosslinker chemistry on membrane properties (morphology, composition, hydrophobicity, and zeta potential) and membrane performance (salt rejection and permeate flux) in aqueous solutions (2,000 mg/L) of four salts (NaCl, MgCl 2 , Na 2 SO 4 , and MgSO 4 ) at pH 4, 6, and 8. We found that an NFC–PVDF membrane with a network of PEI macromolecules crosslinked with trimesoyl chloride has a high water flux (∼30 L m −2 h −1 ) and high rejections for MgCl 2 (∼88 %) and NaCl (∼65 %) at pH 6 using a pressure of 7 bar. The overall results of our study suggest that PVDF nanofibers and hyperbranched PEI are promising building blocks for the fabrication of high performance NF membranes for water purification.

  6. Anion exchange membrane based on alkali doped poly(2,5-benzimidazole) for fuel cell

    CSIR Research Space (South Africa)

    Luo, H

    2012-02-01

    Full Text Available The properties of alkali doped poly(2,5-benzimidazole) membrane with different alkali doping level for fuel cell application is reported in this work. The alkali doping level played an important role for the ion conductivity of the membrane. The ion...

  7. Cross-linked PAN-based thin-film composite membranes for non-aqueous nanofiltration

    KAUST Repository

    Pé rez-Manrí quez, Liliana; Aburabi'e, Jamaliah; Neelakanda, Pradeep; Peinemann, Klaus Viktor

    2015-01-01

    . Permeation and molecular weight cut off (MWCO) experiments using various dyes were done to evaluate the performance of the membranes. Membranes developed by such method show excellent solvent stability toward DMF with a permeance of 1.7 L/m2 h bar and a

  8. Testing and design of radon resisting membranes based on the experience from the Czech Republic

    International Nuclear Information System (INIS)

    Jiranek, M.

    2004-01-01

    Testing of barrier properties of insulating materials against radon is usually based on the measurement of the radon diffusion coefficient. Presented report summarizes results of radon diffusion coefficients measurements in more than 120 insulating materials obtained throughout Europe. All measurements were performed by the Czech Technical University, Faculty of Civil Engineering in cooperation with the Radiation Protection Institute. We have found out that great differences exist in diffusion properties, because the diffusion coefficients vary within eight orders from 10 -15 m 2 /s to 10 -8 m 2 /s. For each material category of different chemical composition statistical evaluation of results is presented. Possibilities of usage of the radon diffusion coefficient for the design of radon resisting membranes are discussed. Based on the experience from the Czech Republic the paper is trying to show that controlling applicability of membranes by setting of the upper limit for the radon diffusion coefficient is not a convenient approach. The main reason is that it is almost impossible to choose correctly one limit value for the whole Europe. The second reason is that a great number of common waterproofing materials have their radon diffusion coefficients above the probable limit value. As a consequence of this the protection against radon will be solved preferably by materials with Al foils, which is from the technical point of view meaningless, because membranes with Al foils have very low elongation and therefore they can very easily loose their barrier properties by destroying of the Al foil. The paper will show that it seems to be reasonable to replace strict limits by the real design of the insulation in dependence on particular building and soil characteristics. The design is proposed to be based on the calculation of the insulation thickness according to the formula: d ≥ l.arc sinh ((α 1 .l.λ.C S .(A f + A w ))/C dif .n.V)) (in m), where C S is the third

  9. Synthesis of nickel-incorporated larch-based carbon membranes with controllable porous structure for gas separation

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Xin; Li, Wei; Huang, Zhanhua; Liu, Shouxin, E-mail: chemist@126.com, E-mail: liushouxin@126.com [Northeast Forestry University, College of Material Science and Engineering (China)

    2015-11-15

    Ni-incorporated larch-based carbon membranes have been synthesized by introducing the Ni(NO{sub 3}){sub 2} into the liquefied larch using liquefied larch sawdust as precursors and F127 as the soft template. The porous structure can be tailored by the amount of Ni(NO{sub 3}){sub 2}, and the Ni and NiO nanoparticles with a size of 10 nm incorporated in the carbon frameworks. The increase in Ni(NO{sub 3}){sub 2} content can lead to the formation of disordered porous structure and shrinkage of carbon frameworks. The Ni-incorporated carbon membranes with largest pores possess highest gas permeation for N{sub 2}, CO{sub 2}, and O{sub 2} of 37.5, 19.8, and 55.5 m{sup 3} cm/m{sup 2} h kPa, which is larger than that of the pure carbon membranes, respectively. However, the poor ordered porous structure caused by adding large amount of Ni(NO{sub 3}){sub 2} can reduce the gas separation performance, which is attributed to the weaken of the molecular sieve function. The results indicate that the incorporation of few nanoparticles into larch-based carbon membranes can improve molecular sieve function.Graphical abstractNi-incorporated larch-based carbon membranes have been synthesized by introducing the Ni(NO{sub 3}){sub 2} into the liquefied larch. The porous structure can be tailored by the amount of Ni(NO{sub 3}){sub 2}, and the Ni and NiO nanoparticles incorporated in the carbon frameworks. The Ni-incorporated carbon membranes with largest pores possess highest gas permeation and gas permseparation.

  10. A positive feedback-based gene circuit to increase the production of a membrane protein

    Directory of Open Access Journals (Sweden)

    Gennis Robert B

    2010-05-01

    Full Text Available Abstract Background Membrane proteins are an important class of proteins, playing a key role in many biological processes, and are a promising target in pharmaceutical development. However, membrane proteins are often difficult to produce in large quantities for the purpose of crystallographic or biochemical analyses. Results In this paper, we demonstrate that synthetic gene circuits designed specifically to overexpress certain genes can be applied to manipulate the expression kinetics of a model membrane protein, cytochrome bd quinol oxidase in E. coli, resulting in increased expression rates. The synthetic circuit involved is an engineered, autoinducer-independent variant of the lux operon activator LuxR from V. fischeri in an autoregulatory, positive feedback configuration. Conclusions Our proof-of-concept experiments indicate a statistically significant increase in the rate of production of the bd oxidase membrane protein. Synthetic gene networks provide a feasible solution for the problem of membrane protein production.

  11. SiC-BASED HYDROGEN SELECTIVE MEMBRANES FOR WATER-GAS-SHIFT REACTION; F

    International Nuclear Information System (INIS)

    Paul K.T. Liu

    2001-01-01

    This technical report summarizes our activities conducted in Yr II. In Yr I we successfully demonstrated the feasibility of preparing the hydrogen selective SiC membrane with a chemical vapor deposition (CVD) technique. In addition, a SiC macroporous membrane was fabricated as a substrate candidate for the proposed SiC membrane. In Yr II we have focused on the development of a microporous SiC membrane as an intermediate layer between the substrate and the final membrane layer prepared from CVD. Powders and supported thin silicon carbide films (membranes) were prepared by a sol-gel technique using silica sol precursors as the source of silicon, and phenolic resin as the source of carbon. The powders and films were prepared by the carbothermal reduction reaction between the silica and the carbon source. The XRD analysis indicates that the powders and films consist of SiC, while the surface area measurement indicates that they contain micropores. SEM and AFM studies of the same films also validate this observation. The powders and membranes were also stable under different corrosive and harsh environments. The effects of these different treatments on the internal surface area, pore size distribution, and transport properties, were studied for both the powders and the membranes using the aforementioned techniques and XPS. Finally the SiC membrane materials are shown to have satisfactory hydrothermal stability for the proposed application. In Yr III, we will focus on the demonstration of the potential benefit using the SiC membrane developed from Yr I and II for the water-gas-shift (WGS) reaction