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Sample records for aot water reverse

  1. Ultrafast energy transfer in water-AOT reverse micelles

    NARCIS (Netherlands)

    Cringus, Dan; Bakulin, Artem; Lindner, Joerg; Voehringer, Peter; Pshenichnikov, Maxim S.; Wiersma, Douwe A.

    2007-01-01

    A spectroscopic investigation of the vibrational dynamics of water in a geometrically confined environment is presented. Reverse micelles of the ternary microemulsion H2O/AOT/n-octane (AOT = bis-2-ethylhexyl sulfosuccinate or aerosol-OT) with diameters ranging from 1 to 10 nm are used as a model sys

  2. Ultrafast energy transfer in water-AOT reverse micelles.

    Science.gov (United States)

    Cringus, Dan; Bakulin, Artem; Lindner, Jörg; Vöhringer, Peter; Pshenichnikov, Maxim S; Wiersma, Douwe A

    2007-12-27

    A spectroscopic investigation of the vibrational dynamics of water in a geometrically confined environment is presented. Reverse micelles of the ternary microemulsion H2O/AOT/n-octane (AOT = bis-2-ethylhexyl sulfosuccinate or aerosol-OT) with diameters ranging from 1 to 10 nm are used as a model system for nanoscopic water droplets surrounded by a soft-matter boundary. Femtosecond nonlinear infrared spectroscopy in the OH-stretching region of H2O fully confirms the core/shell model, in which the entrapped water molecules partition onto two molecular subensembles: a bulk-like water core and a hydration layer near the ionic surfactant headgroups. These two distinct water species display different relaxation kinetics, as they do not exchange vibrational energy. The observed spectrotemporal ultrafast response exhibits a local character, indicating that the spatial confinement influences approximately one molecular layer located near the water-amphiphile boundary. The core of the encapsulated water droplet is similar in its spectroscopic properties to the bulk phase of liquid water, i.e., it does not display any true confinement effects such as droplet-size-dependent vibrational lifetimes or rotational correlation times. Unlike in bulk water, no intermolecular transfer of OH-stretching quanta occurs among the interfacial water molecules or from the hydration shell to the bulk-like core, indicating that the hydrogen bond network near the H2O/AOT interface is strongly disrupted. PMID:18047308

  3. Integral physicochemical properties of reverse micelles of sodium bis(2-ethylhexyl) sulfosuccinate (AOT)

    Science.gov (United States)

    Fedyaeva, O. A.; Shubenkova, E. G.; Poshelyuzhnaya, E. G.; Lutaeva, I. A.

    2016-08-01

    The effect the degree of hydration has on optical and electrophysical properties of water/AOT/ n-hexane system is studied. It is found that AOT reverse micelles form aggregates whose dimensions grow along with the degree of hydration and temperature. Aggregation enhances their electrical conductivity and shifts the UV spectrum of AOT reverse emulsions to the red region. Four states of water are found in the structure of AOT reverse micelles.

  4. Kinetic Studies on the Lignin Peroxidase Catalyzed Oxidation of Veratryl Alcohol by H2O2 in AOT/Isooctane/Toluene/Water Reverse Micelles

    Institute of Scientific and Technical Information of China (English)

    LIU Jin-Ting; HUANG Xi-Rong; GAO Pei-ji

    2007-01-01

    The steady state kinetics of the lignin peroxidase (LIP) catalyzed oxidation of veratryl alcohol (VA) by H2O2 in a sodium bis(2-ethylhexyl) sulfosuccinate (AOT)/isooctane/toluene/water reverse micellar medium was studied and a comparison with the corresponding aqueous medium was made to understand the effect of the reverse micellar medium on the catalytic mechanism and kinetic parameters. Results indicated that the model reaction in the AOT medium were the same as those in bulk aqueous medium, but the kinetic parameters except Km,H2O2 were greatly different in the two media. The kcat and Ki values in the reverse micelle were approximately 2 and 20 times smaller than the corresponding values in the aqueous solution, but the Michaelis constant of VA was approximately 100times greater than that in the aqueous solution. The above mentioned differences in the kinetic parameters were caused by the microheterogeneity and the interface of the AOT reverse micelle, which resulted in the partitioning of VA and H2O2, and by the changes of the conformation of LiP and the reactivity of the substrates.

  5. Photophysical properties of pyronin dyes in reverse micelles of AOT

    Energy Technology Data Exchange (ETDEWEB)

    Bayraktutan, Tuğba; Meral, Kadem; Onganer, Yavuz, E-mail: yonganer@atauni.edu.tr

    2014-01-15

    The photophysical properties of pyronin B (PyB) and pyronin Y (PyY) in reverse micelles formed with water/sodium bis (2-ethyl-1-hexyl) sulfosuccinate (AOT)/n-heptane were investigated by UV–vis absorption, steady-state and time-resolved fluorescence spectroscopy techniques. This study was carried out a wide range of reverse micelle sizes, with hydrodynamic radii ranging from 1.85 to 9.38 nm. Significant photophysical parameters as band shifts, fluorescence quantum yields and fluorescence lifetimes were determined to understand how photophysical and spectroscopic features of the dye compounds were affected by the variation of reverse micelle sizes. In this regard, control of reverse micelle size by changing W{sub 0}, the molar ratio of water to surfactant, allowed tuning the photophysical properties of the dyes in organic solvent via reverse micelle. Non-fluorescent H-aggregates of pyronin dyes were observed for the smaller reverse micelles whereas an increase in the reverse micelle size induced an increment in the amount of dye monomers instead of dye aggregates. Thus, the fluorescence intensities of the dyes were improved by increasing W{sub 0} due to the predomination of the fluorescent dye monomers. As a result, the fluorescence quantum yields also increased. The fluorescence lifetimes of the dyes in the reverse micelles were determined by the time-resolved fluorescence decay studies. Evaluation of the fluorescence lifetimes calculated for pyronin dyes in the reverse micelles showed that the size of reverse micelle affected the fluorescence lifetimes of pyronin dyes. -- Highlights: • The photophysical properties of pyronin dyes were examined by spectroscopic techniques. • Optical properties of the dyes were tuned by changing of W{sub 0} values. • The fluorescence lifetime and quantum yield values of the dyes in reverse micelles were discussed.

  6. Effects of bile salts on percolation and size of AOT reversed micelles.

    Science.gov (United States)

    Yang, Hui; Erford, Karen; Kiserow, Douglas J; McGown, Linda B

    2003-06-15

    The effects of two trihydroxy bile salts, sodium taurocholate (NaTC) and 3-[(3-cholamidylpropyl)dimethylammonio]-1-propane sulfonate (CHAPS), on the size, shape and percolation temperature of reversed micelles formed by sodium bis(2-ethylhexyl)sulfosuccinate (AOT) in isooctane were studied. The percolation temperature of the reversed micelles decreased upon inclusion of bile salts, indicating increased water uptake. Dynamic light scattering (DLS) measurements showed consistent enlargement of reversed micelles upon addition of the bile salts; the hydrodynamic radius increased sixfold in the presence of 10 mM CHAPS and doubled in the presence of 5 mM NaTC. Inclusion of the enzyme yeast alcohol dehydrogenase (YADH) increased the percolation temperature and distorted the spherical structure of the AOT reversed micelles. The spherical structure was restored upon addition of bile salt. These results may help to explain the increase in activity of YADH in AOT reversed micelles upon addition of bile salts.

  7. Interactions between crystal violet and AOT in aqueous solutions and in AOT/isooctane/water microemulsions

    Institute of Scientific and Technical Information of China (English)

    HAO Xiaojuan; AN Xueqin; CHEN Zhiyun; SHEN Weiguo

    2004-01-01

    The absorbance of crystal violet (CV) in a series of aqueous solutions and a series of sodium bis(2-ethyl- hexyl) sulfosuccinate (AOT)/isooctane/water microemulsions has been determined. Association models have been used to analyse the experimental data to obtain the association constants of CV and AOT in the above two media. It was found that about up to 57% CV was associated by AOT in AOT/ isooctane/water microemulsions, which reduced the reaction rate of alkaline fading of crystal violet in the microemulsions.

  8. Application of Multiple Linear Regression and Extended Principal-Component Analysis to Determination of the Acid Dissociation Constant of 7-Hydroxycoumarin in Water/AOT/Isooctane Reverse Micelles.

    Science.gov (United States)

    Caselli; Daniele; Mangone; Paolillo

    2000-01-15

    The apparent pK(a) of dyes in water-in-oil microemulsions depends on the charge of the acid and base forms of the buffers present in the water pool. Extended principal-component analysis allows the precise determination of the apparent pK(a) and of the spectra of the acid and base forms of the dye. Combination with multiple linear regression increases the precision. The pK(a) of 7-hydroxycoumarin (umbelliferone) was spectrophotometrically measured in a water/AOT/isooctane microemulsion in the presence of a series of buffers carrying different charges at various different water/surfactant ratios. The spectra of the acid and base forms of the dye in the microemulsion are very similar to those in bulk water in the presence of Tris and ammonia. The presence of carbonate changes somewhat the spectrum of the acid form. Results are discussed taking into account the profile of the electrostatic potential drop in the water pool and the possible partition of umbelliferone between the aqueous core and the surfactant. The pK(a) values corrected for these effects are independent of w(0) and are close to the value of the pK(a) in bulk water. Copyright 2000 Academic Press.

  9. Determination of the acid dissociation constant of bromocresol green and cresol red in water/AOT/isooctane reverse micelles by multiple linear regression and extended principal component analysis.

    Science.gov (United States)

    Caselli, Maurizio; Mangone, Annarosa; Paolillo, Paola; Traini, Angela

    2002-01-01

    The pKa of 3',3",5',5"tetrabromo-m-cresolsulfonephtalein (Bromocresol Green) and o-cresolsulphonephtalein (Cresol Red) was spectrophotometrically measured in a water/AOT/isooctane microemulsion in the presence of a series of buffers carrying different charges at different water/surfactant ratios. Extended Principal Component Analysis was used for a precise determination of the apparent pKa and of the spectra of the acid and base forms of the dye. The apparent pKa of dyes in water-in-oil microemulsions depends on the charge of the acid and base forms of the buffers present in the water pool. Combination with multiple linear regression increases the precision. Results are discussed taking into account the profile of the electrostatic potential in the water pool and the possible partition of the indicator between the aqueous core and the surfactant. The pKa corrected for these effects are independent of w0 and are close to the value of the pKa in bulk water. On the basis of a tentative hypothesis it is possible to calculate the true pKa of the buffer in the pool.

  10. Molecular Dynamics Simulations of Cytochrome c un-folding in AOT Reverse Micelles: the first steps

    CERN Document Server

    Abel, Stéphane; Marchi, Massimo

    2009-01-01

    This paper explores the reduced form of horse cytochrome c confined in reverse micelles (RM) of so-dium bis-(2-ethylhexyl) sulfosuccinate (AOT) in isooctane by molecular dynamics simulation. RMs of two sizes were constructed at a water content of Wo = [H2O]/[AOT] = 5.5 and 9.1. Our results show that the protein secondary structure and the heme conformation both depend on micellar hydration. At low hydration, the protein structure and the heme moiety remain stable, whereas at high water content the protein becomes unstable and starts to unfold. At Wo = 9.1, according to the X-ray structure, conforma-tional changes are mainly localized on protein loops and around the heme moiety, where we observe a partial opening of the heme crevice. These findings suggest that within our time window (10 ns), the structural changes observed at the heme level are the first steps of the protein denaturation process, pre-viously described experimentally in micellar solutions. In addition, a specific binding of AOT molecules to a ...

  11. Activity, stability and kinetic parameters for -chymotrypsin catalysed reactions in AOT/isooctane reverse micelles with nonionic and zwitterionic mixed surfactants

    Indian Academy of Sciences (India)

    Santosh Kumar Verma; Kallol K Ghosh

    2013-07-01

    Reverse micelles (RMs) of sodium 1,4-bis(2-ethylhexyl)sulphosuccinate (AOT) in nonpolar organic solvents are widely known to have very high solubilization power for water. The method is applied to the hydrolysis of -nitrophenyl acetate (PNPA) catalysed by -chymotrypsin (-CT) in AOT/isooctane/buffer RMs. The increase in -CT activity and stability was an optimum at wo ([H2O]/[AOT]) = 10, z [Isooctane]/[AOT]) = 5. Three typical surfactants were selected based on their head group charges: a non-ionic surfactant Triton-X 100 and two zwitterionic sulphobetaine surfactants of the type CH2+1N+Me2 (CH2)3 SO$^{−}_{3}$ (n = 10; SB3-10, n = 16; SB3-16). The kinetic parameters (such as cat and M) of the -CT at 27°C were determined and compared in the absence and presence of three surfactants. The effect of chain length of zwitterionic surfactant (SB3-10 and SB3-16) on the enzymatic efficacy of -CT as a function of mixed surfactant addition has been investigated in AOT/isooctane RMs at pH 7.75.

  12. Anomalous change in interfacial tension induced by collapses of AOT microemulsions at heptane/water interface

    Science.gov (United States)

    Takahashi, Masahiko; Yui, Hiroharu; Ikezoe, Yasuhiro; Sawada, Tsuguo

    2004-05-01

    Dynamic behavior of water-in-oil microemulsions at the oil/water interface was investigated using the quasi-elastic laser scattering method. We observed an anomalous rebound behavior of interfacial tension γ induced by collapses of microemulsions and adsorptions of AOT molecules at the interface. γ rapidly decreased and reached a minimum value (5.5 mN/m) at about 500 s after the preparation of the interface, and then increased gradually for about 2000 s to the equilibrium value (8.0 mN/m). We considered the mechanism of the rebound behavior in terms of transient change in interfacial thickness induced by the collapses of AOT microemulsions.

  13. Dielectric Properties of Water in Butter and Water-AOT-Heptane Systems Measured using Terahertz Time-Domain Spectroscopy

    DEFF Research Database (Denmark)

    Møller, Uffe; Folkenberg, Jacob Riis; Jepsen, Peter Uhd

    2010-01-01

    We investigate the dielectric properties of water confined in nanometer-sized inverse micelles in mixtures of water, AOT, and heptane. We show that the dielectric properties of the confined water are dependent on the water pool size and different from those of bulk water. We also discuss the diel...... the dielectric properties of different vegetable oils, lard, and butter, and use these properties to deduce the dielectric properties of water in butter, which are shown to deviate significantly from the dielectric properties of bulk water....

  14. Micellar interactions in water-AOT based droplet microemulsions containing hydrophilic and amphiphilic polymers

    Science.gov (United States)

    Appel, Markus; Spehr, Tinka Luise; Wipf, Robert; Moers, Christian; Frey, Holger; Stühn, Bernd

    2013-11-01

    We investigate the influence of addition of hydrophilic and amphiphilic polymer on percolation behavior and micellar interactions in AOT-based water-in-oil droplet microemulsions. We focus on two series of samples having constant molar water to surfactant ratio W = 20 and constant droplet volume fraction Φ = 30%, respectively. From dielectric spectroscopy experiments, we extract the bending rigidity of the surfactant shell by percolation temperature measurements. Depending on droplet size, we find stabilization and destabilization of the surfactant shell upon addition of hydrophilic poly(ethylene glycol) (PEG) (Mn = 3100 g mol-1) and amphiphilic poly(styrene)-b-poly(ethylene glycol) copolymer with comparable length of the hydrophilic block. Complementary small angle X-ray scattering experiments corroborate the finding of stabilization for smaller droplets and destabilization of larger droplets. Subsequent analysis of dielectric spectra enables us to extract detailed information about micellar interactions and clustering by evaluating the dielectric high frequency shell relaxation. We interpret the observed results as a possible modification of the inter-droplet charge transfer efficiency by addition of PEG polymer, while the amphiphilic polymer shows a comparable, but dampened effect.

  15. Degradation of carbofuran derivatives in restricted water environments: basic hydrolysis in AOT-based microemulsions.

    Science.gov (United States)

    Morales, Jorge; Manso, José A; Cid, Antonio; Lodeiro, Carlos; Mejuto, Juan Carlos

    2012-04-15

    The effect of sodium bis(2-ethylhexyl)sulfosuccinate/isooctane/water microemulsions on the stability of 2,2-dimethyl-2,3-dihydro-1-benzofuran-7-yl methylcarbamate (carbofuran, CF), 3-hydroxy-2,3-dihydro-2,2-dimethylbenzofuran-7-yl methylcarbamate (3-hydroxycarbofuran, HCF) and 3-keto-2,3-dihydro-2,2-dimethylbenzofuran-7-yl methylcarbamate (3-ketocarbofuran, KCF) in basic media has been studied. The presence of these microheterogeneous media implies a large basic hydrolysis of CF and HCF on increasing surfactant concentration and, also, on increasing water content in the microemulsion. The hydrolysis rate constants are approximately 2- and 10-fold higher than those in pure water for HCF and CF, respectively. In contrast, a steep descent in the rate of decomposition for KCF was observed. These behaviours can be ascribed to the presence of CF derivatives both in the hydrophilic phase and in the lipophilic phase, while the hydroxyl ions are only restricted to the water pool of the microemulsion (hydrophilic phase). The kinetic rate constants for the basic hydrolysis in AOT-based microemulsions have been obtained on the basis of a pseudophase model. Taking into account that an important part of soils are colloids, the possibility of the presence of restricted water environments implies that soil composition and its structure will play an important role in the stability of these carbamates. In fact, we observed that the presence of these restricted aqueous media in the environment, in particular in watersheds and in wastewaters, could reduce significantly the half-life of these pesticides (33% and 91% for HCF and CF, respectively).

  16. Correlation of insulin-enhancing properties of vanadium-dipicolinate complexes in model membrane systems: phospholipid langmuir monolayers and AOT reverse micelles.

    Science.gov (United States)

    Sostarecz, Audra G; Gaidamauskas, Ernestas; Distin, Steve; Bonetti, Sandra J; Levinger, Nancy E; Crans, Debbie C

    2014-04-22

    We explore the interactions of V(III) -, V(IV) -, and V(V) -2,6-pyridinedicarboxylic acid (dipic) complexes with model membrane systems and whether these interactions correlate with the blood-glucose-lowering effects of these compounds on STZ-induced diabetic rats. Two model systems, dipalmitoylphosphatidylcholine (DPPC) Langmuir monolayers and AOT (sodium bis(2-ethylhexyl)sulfosuccinate) reverse micelles present controlled environments for the systematic study of these vanadium complexes interacting with self-assembled lipids. Results from the Langmuir monolayer studies show that vanadium complexes in all three oxidation states interact with the DPPC monolayer; the V(III) -phospholipid interactions result in a slight decrease in DPPC molecular area, whereas V(IV) and V(V) -phospholipid interactions appear to increase the DPPC molecular area, an observation consistent with penetration into the interface of this complex. Investigations also examined the interactions of V(III) - and V(IV) -dipic complexes with polar interfaces in AOT reverse micelles. Electron paramagnetic resonance spectroscopic studies of V(IV) complexes in reverse micelles indicate that the neutral and smaller 1:1 V(IV) -dipic complex penetrates the interface, whereas the larger 1:2 V(IV) complex does not. UV/Vis spectroscopy studies of the anionic V(III) -dipic complex show only minor interactions. These results are in contrast to behavior of the V(V) -dipic complex, [VO2 (dipic)](-) , which penetrates the AOT/isooctane reverse micellar interface. These model membrane studies indicate that V(III) -, V(IV) -, and V(V) -dipic complexes interact with and penetrate the lipid interfaces differently, an effect that agrees with the compounds' efficacy at lowering elevated blood glucose levels in diabetic rats. PMID:24615733

  17. Trend estimates of AERONET-observed and model-simulated AOTs between 1993 and 2013

    Science.gov (United States)

    Yoon, J.; Pozzer, A.; Chang, D. Y.; Lelieveld, J.; Kim, J.; Kim, M.; Lee, Y. G.; Koo, J.-H.; Lee, J.; Moon, K. J.

    2016-01-01

    Recently, temporal changes in Aerosol Optical Thickness (AOT) have been investigated based on model simulations, satellite and ground-based observations. Most AOT trend studies used monthly or annual arithmetic means that discard details of the generally right-skewed AOT distributions. Potentially, such results can be biased by extreme values (including outliers). This study additionally uses percentiles (i.e., the lowest 5%, 25%, 50%, 75% and 95% of the monthly cumulative distributions fitted to Aerosol Robotic Network (AERONET)-observed and ECHAM/MESSy Atmospheric Chemistry (EMAC)-model simulated AOTs) that are less affected by outliers caused by measurement error, cloud contamination and occasional extreme aerosol events. Since the limited statistical representativeness of monthly percentiles and means can lead to bias, this study adopts the number of observations as a weighting factor, which improves the statistical robustness of trend estimates. By analyzing the aerosol composition of AERONET-observed and EMAC-simulated AOTs in selected regions of interest, we distinguish the dominant aerosol types and investigate the causes of regional AOT trends. The simulated and observed trends are generally consistent with a high correlation coefficient (R = 0.89) and small bias (slope±2σ = 0.75 ± 0.19). A significant decrease in EMAC-decomposed AOTs by water-soluble compounds and black carbon is found over the USA and the EU due to environmental regulation. In particular, a clear reversal in the AERONET AOT trend percentiles is found over the USA, probably related to the AOT diurnal cycle and the frequency of wildfires. In most of the selected regions of interest, EMAC-simulated trends are mainly attributed to the significant changes of the dominant aerosols; e.g., significant decrease in sea salt and water soluble compounds over Central America, increase in dust over Northern Africa and Middle East, and decrease in black carbon and organic carbon over Australia.

  18. Changes in the bending modulus of AOT based microemulsions induced by the incorporation of polymers in the water core.

    Science.gov (United States)

    Kuttich, Björn; Grefe, Ann-Kathrin; Stühn, Bernd

    2016-08-14

    The bending modulus κ is known to be a crucial parameter for the stability of the droplet phase in microemulsion systems. For AOT based water in oil microemulsions the bending modulus of the surfactant has values close to kBT but can be influenced by the presence of polymers. In this work we focus on the water soluble polymer polyethylene glycol and how it influences the bending modulus. An increase by a factor of three is found. For the correct evaluation of the bending modulus via percolation temperatures and droplet radii, thus by dielectric spectroscopy and small angle X-ray scattering, the determination of the radii right at the percolation temperature is crucial as we will show, although it is often neglected. In order to precisely determine the droplet radii we will present a global fitting model which provides reliable results with a minimum number of free fitting parameters. PMID:27416768

  19. FT-IR studies on the conformation and effective head-group area of AOT molecules in W/O microemulsions

    Institute of Scientific and Technical Information of China (English)

    周国伟; 鲍猛; 李干佐; 陈文君

    2002-01-01

    Using Fourier transform infrared(FT-IR) spectroscopy technique, the carbonyl stretching vibration bands of AOT in sodium bis(2-ethylhexyl)sulfosuccinate (AOT)/isooctane/water reverse (W/O) microemulsions system have been investigated by least square curve fitting. The results indicate that an asymmetric adsorbed peak of carbonyl stretching vibration of AOT molecule is situated in (1739 ± 1) and (1725 ± 2) cm-1. The two peaks correspond to different carbonyls in gauche conformation and trans conformation of AOT molecules, respectively. With different water contents (W0), the variations of peak intensity ratio (/= l1739/l1725) reflect the change of the ratio for the two conformation populations and the variations of the effective head-group area of AOT molecule have relations to the ratio of two conformation populations.

  20. A small-angle neutron scattering study of intermicellar interactions in microemulsions of AOT, water, and near-critical propane

    International Nuclear Information System (INIS)

    Small-angle neutron scattering (SANS) measurements of high-pressure solutions of propane/sodium bis(2-ethylhexyl) sulfosuccinate (AOT)/D2O have demonstrated that a water-in-oil microemulsion phase can be formed in propane. The dispersed droplets are, within experimental error, the same size as those formed in conventional microemulsions at the same water-to-surfactant ratio, and the size does not depend on propane density. The interdroplet interaction potential was modeled as a hard-core repulsion augmented by a strong and extremely short range attraction. This model describes droplets whose hydrocarbon tails are strongly attractive to the hydrocarbon tails of adjacent droplets. The SANS fit shows that the magnitude of the tail-tail attractive interactions may be much stronger than the longer range van der Waals type attractive interactions between the water cores of the droplets. These findings confirm results of IR and UV-vis spectroscopic studies of near-critical and supercritical fluid microemulsions

  1. Photoisomerization and reorientational mobility of symmetric carbocyanines in AOT/alkane/polar solvent microemulsions

    Science.gov (United States)

    Dandapat, Manika; Basu, Saswati; Ghosh, Deborin; Mandal, Debabrata

    2014-07-01

    Molecular motion of carbocyanine fluorophores DOCI, DODCI and DTDCI were studied in AOT/n-heptane microemulsions containing added polar solvents: water, methanol or acetonitrile. The response varied remarkably depending on the nature of the fluorophore and polar solvent. When the amount of added polar solvent was low, molecular mobility was invariably retarded, due to a combination of electrostatic and hydrophobic forces that induce the guest fluorophore to cling to the AOT molecules of the host reverse micelle. However, at high amounts of added methanol or water, these interactions diminished considerably, causing increase in the mobility of the guest fluorophores up to different extents.

  2. Study of Ordering for AOT/Water Lamellar Lyotropic Liquid Crystal: Small-angle X-ray Scattering Experiments%小角X射线散射表征AOT/水层状溶致液晶的有序性

    Institute of Scientific and Technical Information of China (English)

    庄文昌; 陈晓; 杨春杰; 王庐岩; 柴永存

    2005-01-01

    用小角X射线散射研究了AOT/水层状溶致液晶的有序性.通过对散射曲线的解析,讨论了表面活性剂浓度、温度和助表面活性剂等三个方面对溶致液晶层状相结构有序性的影响.在一定的范围内,提高温度,改变表面活性剂浓度和加入少量助表面活性剂可使碳氢链排列由稀疏转变为密实,层状相也相应地由"柔性双层"过渡到更加有序化的"平面双层".基于形状因子和体系内分子间作用力,提出了层状相形成与有序化的机理,同时采用分子模拟的方法展现了不同浓度下的液晶结构.%Small-angle X-ray scattering (SAXS) is utilized to study the ordering of AOT/water lamellar phase. As increasing surfactant concentration, temperature or adding cosurfactant in certain range, the arrangement of hydrocarbon chains will change from sparse to dense which results in the structural transformation of lamellar phase from "flexible"to "planar" bilayers. The possible mechanism is proposed based on shape factor and molecular interactions. Molecular simulations are also carried out to testify the obtained results.

  3. USPIO assisting degradation of MXC by host/guest-type immobilized laccase in AOT reverse micelle system.

    Science.gov (United States)

    Yang, Yu-Xiang; Pi, Na; Zhang, Jian-Bo; Huang, Yan; Yao, Ping-Ping; Xi, Yan-Jie; Yuan, Hong-Ming

    2016-07-01

    The laccase and ultrasmall superparamagnetic iron oxide nanoparticles (USPIO) have been assembled inside the tubular mesoporous silica via co-adsorption technology to prepare host/guest-type immobilized laccase, which is applied to degrade methoxychlor (MXC) in aqueous and reverse micelle environments. The effects of various parameters on degradation of MXC were studied. Under the optimum conditions, the degradation rate could reach maximum value of 45.6 % and remain at 20.8 % after seven cycles. Moreover, the addition of small molecular compound 2, 2'-azinobis-(3-ethylbenzthiazoline-6-sulphonate) to the system could greatly improve the degradation efficiency. The MXC degradation process is a first-order reaction, and the activation energy of MXC degradation catalyzed by immobilized laccase (41.46 kJ mol(-1)) is relatively lower than that catalyzed by free laccase (44.91 kJ mol(-1)). Based on the degradation products measured by gas chromatograph-mass spectrometer (GC-MS) and nuclear magnetic resonance (NMR), the degradation mechanism of MXC has also been proposed. PMID:27023821

  4. Factors Affecting Trypsin Extraction by AOT Reversed Micelles and Observation by STM%AOT反胶束萃取胰蛋白酶的STM及主要影响因素

    Institute of Scientific and Technical Information of China (English)

    周小华; 翁亚军

    2006-01-01

    In this article, the influence factors of trypsin extracted from crude pancreatin was investigated, and scanning tunneling microscope(STM) was used to observe the image of trypsin in butane-diacid-2-ethyl-hexyl-ester-sulfonic sodium (AOT)/iso-octane reversed micelles. The STM image showed that trypsins bounded in reversed micelles was rigid, which weakened its conjugative effect and caused maximum ultraviolet absorption and fluorescence emissive absorption moving toward blue waves. AOT concentration, pH and cations were the main influence factors of extraction. Specifically, extraction percentage of trypsin decreased with the increase of AOT concentration from 0.01 to 0.1mol·L-1. When pH value is from 5.30 to 10.0, i.e. less than pI of trypsin, the extraction percentage is raised with the different increase of pI-pH, but when the pH value is less than 5.20, the extraction percentage is decreased with the acidity added. Besides, the extraction efficiency is negative, related with the concentrations of Ca2+, Na+,K+ which were in the range of 0.2-1.0mol· L-1, and influence of concentration of Ca2+ is greater than that of Na+, and K+ which has the minimum impact with the same concentration. Finally, optimum conditions to extract trypsin were: AOT reversed micelles 0.05mol·L-1, trypsin concentration in crude pancreatin solution 3mg·ml-1, pH 5.2- 5.3, ratio (by volume) of extraction phase to strip-extraction phase 1:1, and time of 5min. The corresponding percentage of extraction was 22.7% and specific activity was 78.9 N-benzoyl-L-arginine ethyl ester (BAEE) U·mg-1 protein, three times than that in crude pancreatin. There was no lipase and amylopsin activity was decreased to 1/5 of crude pancreatin. Partly purifying solution was treated by condition mentioned above with 0.05mol·L-1 ceryl-trimethyl-ammonium bromide (CTAB), total extraction percentage of trypsin was 74.18% and specific activity was 3148.3 BAEE U·mg-1, i.e. 48.16 times purer than that in crude

  5. Ramping of pH Across the Water-Pool of a Reverse Micelle.

    Science.gov (United States)

    Mukherjee, Puspal; Gupta, Shradhey; Rafiq, Shahnawaz; Yadav, Rajeev; Jain, Vipin Kumar; Raval, Jayraj; Sen, Pratik

    2016-02-23

    In this work, we have addressed the problem of "acidity" of the water-pool of a reverse micelle (RM) through the well-known inversion of sucrose reaction as a tool of investigation. This reaction has been performed inside positively and negatively charged RM and the rates are compared with that in bulk water. We propose that the buffer-like action in a water-pool is much stronger than expected earlier. The rate of sucrose hydrolysis slowed down in the negatively charged AOT reverse micelle while it sped up for the positively charged CTAB reverse micelle. However, temperature-dependent measurements showed that the activation energy remained the same for all the cases. It has been concluded that a proton gradient exists inside the water-pool of the reverse micelle and it determines the buffer-like action of the water-pool that persists until about 2 N of HCl in AOT RM of w(0) = 10.5.

  6. Porphyrins in Reverse Micelles:the Side-chain Length and the Triplet-state Lifetime

    Institute of Scientific and Technical Information of China (English)

    Jun Hua YU; Yu Xiang WENG; Xue Song WANG; Lei ZHANG; Bao Wen ZHANG; Yi CAO

    2003-01-01

    Using bis(2-ethylhexyl) sodium sulfosuccinate (AOT) as surfactant, two amphiphilic porphyrin terminated with imidazole were studied in AOT/iso-octane/water reverse micelles, intending to mimic the relationship between microenvironments in organism and the amphiphilic properties of porphyrins for photodynamic therapy drugs.

  7. Temperature control of pattern formation in the Ru(bpy)(3)(2+)-catalyzed BZ-AOT system.

    Science.gov (United States)

    McIlwaine, Rachel; Vanag, Vladimir K; Epstein, Irving R

    2009-03-14

    Using temperature as a control parameter, we observe a transition from stationary Turing patterns at T = 15-20 degrees C to traveling waves at T = 50 degrees C (and above) in the Ru(bpy)(3)(2+)-catalyzed Belousov-Zhabotinsky (BZ) reaction incorporated into the water nanodroplets of a water-in-oil aerosol OT (AOT) microemulsion. At constant chemical composition, molar ratio and droplet fraction, the transition takes place via a series of stable patterns, including oscillatory Turing patterns (at 35-40 degrees C) and reversed oscillatory Turing patterns (at 50 degrees C). We attribute the pattern transitions to a temperature-induced percolation transition of the BZ-AOT microemulsion, implying a change from isolated water nanodroplets to a system-spanning network of water channels. PMID:19240935

  8. Associated electron and proton transfer between Acridine and Triethylamine in AOT reverse micelles probed by laser flash photolysis with magnetic field

    Science.gov (United States)

    Sarangi, Manas Kumar; Basu, Samita

    2011-04-01

    Laser flash photolysis with magnetic field (MF ˜0.08 T) has been used to study interaction between Acridine (Acr) and Triethylamine (TEA) in reverse micelles with w0 = 2.5-40. Dynamic protonation equilibrium exists between 3Acr and 3AcrH +. The intermediates indicate excited-state proton transfer (PT) between 3AcrH + and TEA. However, application of MF highlights the formation of geminate radical ion pairs (RIPs) with triplet spin-correlation, a signature of latent photoinduced electron transfer between 3AcrH + and TEA co-exists with PT. Magnetic field effect (MFE) is prominent for smaller w0 showing importance of optimum separation between RIP to maximize MFE, whereas PT remains unaltered.

  9. Absorption Complex between Porphyrin and Phenothiazine in Reverse Micelles

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The interaction between amphiphilic porphyrin and phenothiazine in AOT/isooctane/ water reverse micelle was investigated by UV-Vis spectra. A new absorption complex between the two species is formed in such circumstances, which is ascribed to the enrichment of the components by the reverse micelle. The fluorescence quenching of CHTTP by PTH becomes more efficient after the formation of the absorption complex.

  10. Nanoparticles synthesis of tungsten disulfide via AOT-based microemulsions

    International Nuclear Information System (INIS)

    Graphical abstract: A controlled synthesis of WS2 nanoparticles (most probably inorganic fullerene (IF)) via microemulsion was applied for the first time to prepare WS2 (7–12 nm) by acidification of the water cores of the AOT reverse microemulsion. Highlights: ► An innovative reverse microemulsion technique was developed for WS2 synthesis. ► WS2 nanoparticles were obtained with narrow size distribution in range of 7–12 nm. ► Operating cost of microemulsion was lower in contrast to quartz reactor method. ► WS2 morphology could be controlled to obtain highly active and selective catalysts. ► Lower size of WS2 in this study overcomes the shortcoming of quartz reactor method. -- Abstract: The tungsten disulfide (WS2) nanoparticles (most probably inorganic fullerene (IF)) with a narrow size distribution were synthesized by a reverse micelle technique for the first time. The particle size was controlled by varying water-to-surfactant molar ratio (W0), aging time and reagent concentration. The synthesized WS2 nanoparticles were characterized by zetasizer, UV–visible spectrophotometers and transmission electron microscopy (TEM). The WS2 nanoparticles with particle diameter size of 7–12 nm were obtained via 24 h aging time. The particle size was controlled by changing the aging time and molar ratio of water/surfactant. Doubling W0 increased the amount and particle size of WS2 by 22 and 26%, respectively. The effect of aging time in the range of 6–24 h was investigated and the complete disappearance of yellowish color at 24 h resulted in an optically clear solution, which was the indication of WS2 formation with 100% conversion of reactant ((NH4)2WS4) in the batch reactor.

  11. Phase behavior of supercritical CO2 microemulsion with food-grade surfactant AOT

    Institute of Scientific and Technical Information of China (English)

    ZHOU Yongsheng; AN Xueqin; SHEN Weiguo; ZHANG Yinghua

    2006-01-01

    Phase behavior of scCO2 microemulsion formed with food grade surfactant sodium bis-(2-ethylhexyl) sulfosuccinate (AOT) was studied. Critical microemulsion concentration (cμc) was deduced from the dependence of pressure of cloud points on the concentration of surfactant AOT at constant temperature and water concentration. The results show that there are transition points on the cloud point curve in a very narrow range of concentration of surfactant AOT. The transition points were changed with the temperature and water concentration. These phenomena show that lower temperature is suitable to forming microemulsion droplet and the microemulsion with high water concentration is likely to absorb more surfactants to structure the interface.

  12. Rotating Reverse-Osmosis for Water Purification

    Science.gov (United States)

    Lueptow, RIchard M.

    2004-01-01

    A new design for a water-filtering device combines rotating filtration with reverse osmosis to create a rotating reverse- osmosis system. Rotating filtration has been used for separating plasma from whole blood, while reverse osmosis has been used in purification of water and in some chemical processes. Reverse- osmosis membranes are vulnerable to concentration polarization a type of fouling in which the chemicals meant not to pass through the reverse-osmosis membranes accumulate very near the surfaces of the membranes. The combination of rotating filtration and reverse osmosis is intended to prevent concentration polarization and thereby increase the desired flux of filtered water while decreasing the likelihood of passage of undesired chemical species through the filter. Devices based on this concept could be useful in a variety of commercial applications, including purification and desalination of drinking water, purification of pharmaceutical process water, treatment of household and industrial wastewater, and treatment of industrial process water. A rotating filter consists of a cylindrical porous microfilter rotating within a stationary concentric cylindrical outer shell (see figure). The aqueous suspension enters one end of the annulus between the inner and outer cylinders. Filtrate passes through the rotating cylindrical microfilter and is removed via a hollow shaft. The concentrated suspension is removed at the end of the annulus opposite the end where the suspension entered.

  13. Studies on Production of Erucic Acid by Enzume-Catalyzed Hydrolysis in AOT/isooctane Reversed Micelle System%反胶束酶水解法生产芥酸的工艺研究

    Institute of Scientific and Technical Information of China (English)

    周茂洪; 赵肖为; 吴蓉蓉; 余佳佳

    2006-01-01

    为了优化酶水解法生产芥酸的工艺条件,在AOT/异辛烷反胶束体系中,选择合适的脂肪酶,并考察其水解的影响因素.结果表明:来源于洋葱假单胞菌(Pseudomonas cepacia)的脂肪酶对于高芥酸菜子油的水解能力强.当反胶束体系含水量为11,pH值为7.0,菜子油浓度为15%(v/v),水解温度为35℃,反应不到1 h,水解率即达到50%;反应24 h,水解完全.

  14. Correlation between AERONET AOT and VIIRS EDR AOT: A new EDR cell

    Science.gov (United States)

    Molinie, J.; Henry, J. L.; Clement, J.; Euphrasie-Clotilde, L.; Brute, F. N.

    2015-12-01

    Every year, a huge mass of desert dusts lifted from Saharan and sub Saharan regions is injected over the Atlantic Ocean and bring to the Caribbean and the American continent. Guadeloupe a West Indies island, is affected by the presence of dusts particles which impact the air quality and acts on human health. The effect produced by the particles in the atmosphere can be observed by satellite. VIIRS is one the latest tools provided by NASA, to help scientific community to have a better understanding of aerosol behavior. In this job we try to found a link between ground measurement AOT and VIIRS data.In Guadeloupe, AOT measurements have been performed with sun photometer of AERONET network. We calculated AOT at 500 nm mean daily sun photometer data in order to compare them with AOT EDR 550 data computed by NOAA Aerosol calibration and validation team. Three AOT EDR cells, located over the ocean and close to the East coast of the island of have been chosen to evaluate the correlation between ground and satellite data. We obtained using data performed from May to December 2012, correlation coefficient range between 0.8 and 0.87. We observed numerous AOT EDR 550 have been computed with a number of IP pixel, nAOT very low. We proposed to used only cases with nAOT equal or higher than 10. The correlation coefficients improved and reached 0.9. However, those good results have been obtained with a day number reduced by almost 50 per cent.In order to keep a good correlation and a higher number of day we rebuilt a cell by merging two cells. We obtained a new cell with an AOT EDR value equal to the mean AOT EDR of the two parents' value and a nAOT the sum of the previous nAOTs. The results with the new nAOT equal of higher than 10 is, r =0.91 and we keep 75 per cent of the cases.

  15. Layers of Metal Nanoparticles on Semiconductors Deposited by Electrophoresis from Solutions with Reverse Micelles

    Directory of Open Access Journals (Sweden)

    Fojtik A

    2007-01-01

    Full Text Available AbstractPd nanoparticles were prepared with reverse micelles of water/AOT/isooctane solution and deposited onto silicon or InP substrates by electrophoresis. A large change of capacitance-voltage characteristics of mercury contacts on a semiconductor was found after Pd deposition. This change could be modified when the Pd deposition is followed by a partial removal of the deposited AOT. The deposited Pd nanoparticles were investigated by optical mictroscopy, SIMS and SEM. Finally, Schottky diodes with barrier height as high as 1.07 eV were prepared by deposition of Pd nanoparticles on n-type InP and by a partial removal of superfluous AOT. These diodes are prospective structures for further testing as hydrogen sensors.

  16. Reverse osmosis desalination: water sources, technology, and today's challenges.

    Science.gov (United States)

    Greenlee, Lauren F; Lawler, Desmond F; Freeman, Benny D; Marrot, Benoit; Moulin, Philippe

    2009-05-01

    Reverse osmosis membrane technology has developed over the past 40 years to a 44% share in world desalting production capacity, and an 80% share in the total number of desalination plants installed worldwide. The use of membrane desalination has increased as materials have improved and costs have decreased. Today, reverse osmosis membranes are the leading technology for new desalination installations, and they are applied to a variety of salt water resources using tailored pretreatment and membrane system design. Two distinct branches of reverse osmosis desalination have emerged: seawater reverse osmosis and brackish water reverse osmosis. Differences between the two water sources, including foulants, salinity, waste brine (concentrate) disposal options, and plant location, have created significant differences in process development, implementation, and key technical problems. Pretreatment options are similar for both types of reverse osmosis and depend on the specific components of the water source. Both brackish water and seawater reverse osmosis (RO) will continue to be used worldwide; new technology in energy recovery and renewable energy, as well as innovative plant design, will allow greater use of desalination for inland and rural communities, while providing more affordable water for large coastal cities. A wide variety of research and general information on RO desalination is available; however, a direct comparison of seawater and brackish water RO systems is necessary to highlight similarities and differences in process development. This article brings to light key parameters of an RO process and process modifications due to feed water characteristics.

  17. A small angle neutron scattering study on the mixtures of pluronic L121 and anionic surfactant AOT

    Indian Academy of Sciences (India)

    G Ghosh; V K Aswal; D Varade

    2008-11-01

    Small angle neutron scattering (SANS) experiments have been carried out on the micellar solutions containing mixtures of a hydrophobic triblock copolymer (L121, EO5PO68EO5) and a hydrophobic anionic surfactant (AOT, sodium bis(2-ethylhexyl)sulphosuccinate) in water with varying ratio () of AOT to L121 for = 0.15, 0.2, 0.3, 0.5 and 0.6. It is known that either L121 or AOT alone forms vesicles in water, but in the mixture with appropriate ratio of the two components a thermodynamically stable, isotropic solution of apparently small micelle-like aggregates is formed. We find that these micelles are prolate ellipsoidal.

  18. AOT-based microemulsions accelerate the 1,3-cycloaddition of benzonitrile oxide to N-ethylmaleimide

    NARCIS (Netherlands)

    Engberts, J. B. F. N.; Fernandez, E.; Garcia-Rio, L.; Leis, J. R.

    2006-01-01

    We studied the 1,3-dipolar cycloaddition of benzonitrile oxide to N-ethylmaleimide in AOT/isooctane/water microemulsions at 25.0 degrees C and found the reaction rate to be roughly 150 and 35 times greater than that in isooctane and pure water, respectively. The accelerating effect of the microemuls

  19. Ultrafast vibrational dynamics of water confined in phospholipid reverse micelles

    Directory of Open Access Journals (Sweden)

    Elsaesser T.

    2013-03-01

    Full Text Available We study the ultrafast dynamics of OH stretching and bending vibrations of water inside dioleoylphosphatidylcholine (DOPC reverse micelles in a wide range of hydration. A strong hydration level dependence for the spectral diffusion rates is found and explained by the distinctly different environment for single water molecules bound to the anionic phosphate group. We show that the energy relaxation pathway of the OH stretching vibration at low hydration level involves the OH bending.

  20. AOT-microemulsions-based formation and evolution of PbWO$_{4}$ crystals

    CERN Document Server

    Chen, D; Tang Kai Bin; Liang Zhen Hua; Zheng Hua Gui

    2004-01-01

    Anionic surfactant-AOT-microemulsions-assisted formation and evolution of PbWO//4 nanostructures with bundles rodlike, ellipsoidlike, and spherelike prepared at different media conditions were studied by powder X-ray diffraction pattern, field emission scanning electron microscopy, and transmission electron microscopy. The possible mechanisms for the formation of PbWO//4 samples in series of microemulsion systems were discussed. Various comparison experiments show that several experimental parameters, such as the AOT concentration, the water content, and reaction temperature play important roles in the morphological control of PbWO//4 nanostructures. Room-temperature photoluminescence of PbWO//4 samples with different morphologies has also been investigated and the results reveal that all these samples showed similar features with emissions at 480 similar to 510 nm but different luminescence intensity. 40 Refs.

  1. Inhibited phenol ionization in reverse micelles: confinement effect at the nanometer scale.

    Science.gov (United States)

    Silva, O Fernando; Fernández, Mariana A; Silber, Juana J; de Rossi, Rita H; Correa, N Mariano

    2012-01-16

    We found that the absorption spectra of 2-acetylphenol (2-HAP), 4-acetylphenol (4-HAP), and p-nitrophenol (p-NPh) in water/sodium 1,4-bis(2-ethylhexyl)sulfosuccinate (AOT)/n-heptane reverse micelles (RMs) at various W(0) (W(0) = [H(2)O]/[surfactant]) values studied changed with time if (-)OH ions were present in the RM water pool. There is an evolution of ionized phenol (phenolate) bands to nonionized phenol absorption bands with time and this process is faster at low W(0) values and with phenols with higher bulk water pK(a) values. That is, in bulk water and at the hydroxide anion concentration used, only phenolate species are observed, whereas in AOT RMs at this fixed hydroxide anion concentration, ionized phenols convert into nonionized phenol species over time. Furthermore, we demonstrate that, independent of the (-)OH concentration used to prepare the AOT RMs, the nonionized phenols are the more stable species in the RM media. We explain our results by considering that strong hydrogen-bonding interactions between phenols and the AOT polar head groups result in the existence of only nonionized phenols at the AOT RM interface. The situation is quite different when the phenols are dissolved in cationic benzyl-n-hexadecyldimethylammonium chloride RMs. Therein, only phenolates species are present at the (-)OH concentrations used. The results clearly demonstrate that the classical definition of pH does not apply in a confined environment, such as in the interior of RMs and challenge the general idea that pH can be determined inside RMs.

  2. Reverse osmosis membrane of high urea rejection properties. [water purification

    Science.gov (United States)

    Johnson, C. C.; Wydeven, T. J. (Inventor)

    1980-01-01

    Polymeric membranes suitable for use in reverse osmosis water purification because of their high urea and salt rejection properties are prepared by generating a plasma of an unsaturated hydrocarbon monomer and nitrogen gas from an electrical source. A polymeric membrane is formed by depositing a polymer of the unsaturated monomer from the plasma onto a substrate, so that nitrogen from the nitrogen gas is incorporated within the polymer in a chemically combined form.

  3. Preparation and Characterization of Nanosized Hydroxyapatite Particles in AOT Inverse Microemulsion

    Institute of Scientific and Technical Information of China (English)

    REN Wei; LI Shi-pu; WANG You-fa; CAO Xian-ying; CHEN Xiao-ming

    2004-01-01

    Nanosized particles of hydroxyapatite (HAP) were synthesized by reacting Ca(H2PO4)2*H2O solution complex with equimolar Ca(OH)2 saturated solution in sodium bis(2-ethylhexyl) sulfosuccinate (AOT)/isooctane water-in-oil microemulsion.The formation of microemulsion strongly depended on water content w (w=[H2O]/[AOT] molar ratio) and concentration of surfactant and cosurfactant (1-octanol).By the variety of conductivity with w and the partial ternary phase diagram derived from a series of demarcation points,we set the basic component of microemulsions:[AOT]=0.1M(mol/dm3),[1-octanol]=0.1M and w=3-9.Dynamic light scattering (DLS),UV-visible absorbance,TEM analysis and X-ray diffraction were used to characterize the microemulsion,formation of particles and resulting HAP particles.At low water content(w<9),the water pool radius of the droplet in the Ca(H2PO4)2*H2O microemulsion lineally depended on w.The size of final HAP particles was strongly affected by water content w and reactant concentration.With increasing water content w from 3 to 9,the size of HAP particles increased from 10-20nm to 40-50 nm at reactant concentration [Ca(H2PO4)2*H2O]=12×10-3 mol/dm3.The resulting HAP particles were poorly crystallized and spherical in morphology.

  4. Droplet polydispersity and shape fluctuations in AOT [bis(2-ethylhexyl)sulfosuccinate sodium salt] microemulsions studied by contrast variation small-angle neutron scattering

    DEFF Research Database (Denmark)

    Arleth, L.; Pedersen, J.S.

    2001-01-01

    -angle scattering for 11 different contrasts evenly distributed around the match points are studied for each sample. The scattering data for the different contrasts are analyzed using a molecular constrained model for ellipsoidal droplets of water covered by AOT, interacting as polydisperse hard spheres. All......Microemulsions consisting of AOT water, and decane or iso-octane are studied in the region of the phase diagram where surfactant covered water droplets are formed. The polydispersity and shape fluctuations of the microemulsion droplets are determined and compared in the two different alkane types...

  5. Molecular level water and solute transport in reverse osmosis membranes

    Science.gov (United States)

    Lueptow, Richard M.; Shen, Meng; Keten, Sinan

    2015-11-01

    The water permeability and rejection characteristics of six solutes, methanol, ethanol, 2-propanol, urea, Na+, and Cl-, were studied for a polymeric reverse osmosis (RO) membrane using non-equilibrium molecular dynamics simulations. Results indicate that water flux increases with an increasing fraction of percolated free volume in the membrane polymer structure. Solute molecules display Brownian motion and hop from pore to pore as they pass through the membrane. The solute rejection depends on both the size of the solute molecule and the chemical interaction of the solute with water and the membrane. When the open spaces in the polymeric structure are such that solutes have to shed at least one water molecule from their solvation shell to pass through the membrane molecular structure, the water-solute pair interaction energy governs solute rejection. Organic solutes more easily shed water molecules than ions to more readily pass through the membrane. Hydrogen-bonding sites for molecules like urea also lead to a higher rejection. These findings underline the importance of the solute's solvation shell and solute-water-membrane chemistry in solute transport and rejection in RO membranes. Funded by the Institute for Sustainability and Energy at Northwestern with computing resources from XSEDE (NSF grant ACI-1053575).

  6. Water aging reverses residual stresses in hydrophilic dental composites.

    Science.gov (United States)

    Park, J W; Ferracane, J L

    2014-02-01

    Dental composites develop residual stresses during polymerization due to shrinkage. These stresses may change with time because of relaxation and water sorption in the oral environment. This phenomenon is likely dependent on the composition of the materials, specifically their hydrophilic characteristics, and could result in deleterious stresses on restorative materials and tooth structure. The purpose of this experiment was to use the thin ring-slitting method to compare the residual stress generated within composite materials of varying hydrophilicity when aged in wet and dry conditions after polymerization. Water sorption, solubility, elastic modulus, and residual stresses were measured in 6 commercial composites/cements aged in water and dry conditions. The self-adhesive resin cement showed the highest water sorption and solubility. All composites showed initial residual contraction stresses, which were maintained when aged dry. Residual stresses in 2 of the self-adhesive cements and the polyacid-modified composite aged in wet conditions resulted in a net expansion. This experiment verified that residual shrinkage stresses in dental composites can be reversed during aging in water, resulting in a net expansion, with the effect directly related to their hydrophilic properties.

  7. Biosensors with reversed micelle-enzyme sensitive membrane

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The effect of reversed micelle on the conformation of enzyme was studied by sensor techniques. By means of measurement of the response current of GOD enzyme membrane electrode, the effects of enzyme embedded in AOT reversed micellar on GOD conformation and catalytic activity are discussed. The results show that the response current increased greatly with decreasing ratio of GOD/AOT, meaning that the catalytic activity and the conformation stability of enzyme were enhanced.

  8. MODIFIED REVERSE OSMOSIS SYSTEM FOR TREATMENT OF PRODUCED WATERS

    Energy Technology Data Exchange (ETDEWEB)

    T.M. Whitworth; Liangxiong Li

    2002-09-15

    This report describes work performed during the second year of the project ''Modified reverse osmosis system for treatment of produced waters.'' We performed two series of reverse osmosis experiments using very thin bentonite clay membranes compacted to differing degrees. The first series of 10 experiments used NaCl solutions with membranes that ranged between 0.041 and 0.064mm in thickness. Our results showed compaction of such ultra-thin clay membranes to be problematic. The thickness of the membranes was exceeded by the dimensional variation in the machined experimental cell and this is believed to have resulted in local bypassing of the membrane with a resultant decrease in solute rejection efficiency. In two of the experiments, permeate flow was varied as a percentage of the total flow to investigate results of changing permeate flow on solute rejection. In one experiment, the permeate flow was varied between 2.4 and 10.3% of the total flow with no change in solute rejection. In another experiment, the permeate flow was varied between 24.6 and 52.5% of the total flow. In this experiment, the solute rejection rate decreased as the permeate occupied greater fractions of the total flow. This suggests a maximum solute rejection efficiency for these clay membranes for a permeate flow of between 10.3 and 24.6% of the total; flow. Solute rejection was found to decrease with increasing salt concentration and ranged between 62.9% and 19.7% for chloride and between 61.5 and 16.8% for sodium. Due to problems with the compaction procedure and potential membrane bypassing, these rejection rates are probably not the upper limit for NaCl rejection by bentonite membranes. The second series of four reverse osmosis experiments was conducted with a 0.057mm-thick bentonite membrane and dilutions of a produced water sample with an original TDS of 196,250 mg/l obtained from a facility near Loco Hill, New Mexico, operated by an independent. These experiments

  9. Spontaneous vesicle formation from DSB/AOT mixed system

    Institute of Scientific and Technical Information of China (English)

    CHEN Wenjun; ZHAI Limin; LI Ganzuo; MENG Xiangguang; ZENG Xiancheng

    2003-01-01

    Spontaneous vesicles from the aqueous mixtures of dodecyl sulfonate betaine (DSB) and sodium bis (2-ethylhexyl) sulfosuccinate (AOT) at certain mixingratios have been demonstrated by using calorimetry, freeze-frac- ture transmission electronic microscopy (TEM), negative- staining TEM and dynamic light scattering (DLS) methods. The addition of NaCl will promote vesicle formation and the heat effect of monodisperse vesicle system is greatest. Meanwhile the mechanism was analyzed from the viewpoint of packing parameter f, molecular geometry structure and interaction.

  10. MODIFIED REVERSE OSMOSIS SYSTEM FOR TREATMENT OF PRODUCED WATERS

    Energy Technology Data Exchange (ETDEWEB)

    T.M. Whitworth; Liangxiong Li

    2002-09-15

    This report describes work performed during the first year of the project ''Modified Reverse Osmosis System for Treatment of Produced Waters.'' This research project has two objectives. The first objective is to test the use of clay membranes in the treatment of produced waters by reverse osmosis. The second objective is to test the ability of a system patented by the New Mexico Tech Research Foundation to remove salts from reverse osmosis waste streams as a solid. We performed 12 experiments using clay membranes in cross-flow experimental cells. We found that, due to dispersion in the porous frit used adjacent to the membrane, the concentration polarization layer seems to be completely (or nearly completely) destroyed at low flow rates. This observation suggests that clay membranes used with porous frit material many reach optimum rejection rates at lower pumping rates than required for use with synthetic membranes. The solute rejection efficiency decreases with increasing solution concentration. For the membranes and experiments reported here, the rejection efficiency ranged from 71% with 0.01 M NaCl solution down to 12% with 2.3 M NaCl solution. More compacted clay membranes will have higher rejection capabilities. The clay membranes used in our experiments were relatively thick (approximately 0.5 mm). The active layer of most synthetic membranes is only 0.04 {micro}m (0.00004 mm), approximately 1250 times thinner than the clay membranes used in these experiments. Yet clay membranes as thin as 12 {micro}m have been constructed (Fritz and Eady, 1985). Since Darcy's law states that the flow through a material of constant permeability is inversely proportional to it's the material's thickness, then, based on these experimental observations, a very thin clay membrane would be expected to have much higher flow rates than the ones used in these experiments. Future experiments will focus on testing very thin clay membranes. The

  11. Activity and stability of yeast alcohol dehydrogenase (YADH) entrapped in aerosol OT reverse micelles.

    Science.gov (United States)

    Sarcar, S; Jain, T K; Maitra, A

    1992-02-20

    The activity and stability of yeast alcohol dehydrogenase (YADH) entrapped in aerosol OT reverse micellar droplets have been investigated spectrophotometrically. Various physical parameters, e.g., water pool size, w(0), pH, and temperature, were optimized for YADH in water/AOT/isooctane reverse micelles. It was found that the enzyme exhibits maximum activity at w(0) = 28 and pH 8.1. It was more active in reverse micelles than in aqueous buffers at a particular temperature and was denatured at about 307 degrees C in both the systems. At a particular temperature YADH entrapped in reverse micelles was less stable than when it was dissolved in aqueous buffer.

  12. Doping silver nanoparticles in AOT lyotropic lamellarphases

    Institute of Scientific and Technical Information of China (English)

    CHEN; Xiao

    2001-01-01

    aerosol OT/water/oil system, J. Colloid Interface Sci., 1979, 70: 577-583.[15]Fontell, K., The structure of the lamellar liquid crystalline phase in serosol OT-water system, J. Colloid Interface Sci.,1973, 44: 318-329.[16]Kotlarchyk, M., Sheu, E. Y., Capel, M., Structural and dynamical transformations between neighboring dense microemulsion phases, Phys. Rev. A, 1992, 46: 928-939.[17]Antelmi, D. A., Kekicheff, P., Measurement of the compressibility modulus in a lyotropic lamellar phase stabilized by undulation forces, J. Phys. Chem. B, 1997, 101: 8169-8179.[18]Wang, W., Efrima, S., Regev, O., Directing silver nanoparticles into colloid-surfactant lyotropic lamellar systems, J. Phys.Chem. B, 1999, 103: 5613-5621.[19]Chidichimo, G., La Mesa, C., Ranieri, G. A. et al., NMR investigation of the lamellar mesophase occuring in the system aerosol OT-water, Mol. Cryst. Liq. Cryst., 1987, 150b: 221-236.[20]Callaghan, P. T., Soderman, O., Examination of the lamellar phase of aerosol OT/water using pulsed field gradient nuclear magnetic resonance, J. Phys. Chem., 1983, 87: 1737-744.

  13. Domestic wash water reclamation for reuse as commode water supply using filtration: Reverse-osmosis separation technique

    Science.gov (United States)

    Hall, J. B., Jr.; Batten, C. E.; Wilkins, J. R.

    1974-01-01

    A combined filtration-reverse-osmosis water recovery system has been evaluated to determine its capability to reclaim domestic wash water for reuse as a commode water supply. The system produced water that met all chemical and physical requirements established by the U.S. Public Health Service for drinking water with the exception of carbon chloroform extractables, methylene blue active substances, and phenols. It is thought that this water is of sufficient quality to be reused as commode supply water. The feasibility of using a combined filtration and reverse-osmosis technique for reclaiming domestic wash water has been established. The use of such a technique for wash-water recovery will require a maintenance filter to remove solid materials including those less than 1 micron in size from the wash water. The reverse-osmosis module, if sufficiently protected from plugging, is an attractive low-energy technique for removing contaminants from domestic wash water.

  14. MODIFIED REVERSE OSMOSIS SYSTEM FOR TREATMENT OF PRODUCED WATERS

    Energy Technology Data Exchange (ETDEWEB)

    Robert L. Lee; Junghan Dong

    2004-06-03

    This final report of ''Modified Reverse Osmosis System for Treatment of Produced Water,'' DOE project No. DE-FC26-00BC15326 describes work performed in the third year of the project. Several good results were obtained, which are documented in this report. The compacted bentonite membranes were replaced by supported bentonite membranes, which exhibited the same salt rejection capability. Unfortunately, it also inherited the clay expansion problem due to water invasion into the interlayer spaces of the compacted bentonite membranes. We noted that the supported bentonite membrane developed in the project was the first of its kind reported in the literature. An {alpha}-alumina-supported MFI-type zeolite membrane synthesized by in-situ crystallization was fabricated and tested. Unlike the bentonite clay membranes, the zeolite membranes maintained stability and high salt rejection rate even for a highly saline solution. Actual produced brines from gas and oil fields were then tested. For gas fields producing brine, the 18,300 ppm TDS (total dissolved solids) in the produced brine was reduced to 3060 ppm, an 83.3% rejection rate of 15,240 ppm salt rejection. For oilfield brine, while the TDS was reduced from 181,600 ppm to 148,900 ppm, an 18% rejection rate of 32,700 ppm reduction, the zeolite membrane was stable. Preliminary results show the dissolved organics, mainly hydrocarbons, did not affect the salt rejection. However, the rejection of organics was inconclusive at this point. Finally, the by-product of this project, the {alpha}-alumina-supported Pt-Co/Na Y catalytic zeolite membrane was developed and demonstrated for overcoming the two-step limitation of nonoxidation methane (CH{sub 4}) conversion to higher hydrocarbons (C{sub 2+}) and hydrogen (H{sub 2}). Detailed experiments to obtain quantitative results of H{sub 2} generation for various conditions are now being conducted. Technology transfer efforts included five manuscripts submitted to

  15. Reversibility, Water-Mediated Switching, and Directed Cell Dynamics

    OpenAIRE

    J. C. Phillips

    2008-01-01

    Reversible switching of the complex network dynamics of proteins is mimicked in selected network glasses and compacted small carbohydrate molecules. Protein transitions occur on long time scales ~ us -ms, evocative of the exponentially large viscosities found in glass-forming supercooled liquids just above the glass transition; in searching for mechanisms for reversibly slowed "geared activation", Kauzmann was led from proteins to glasses. I show here that selected network glasses and small c...

  16. Reversible assembly of oppositely charged hairy colloids in water

    NARCIS (Netherlands)

    Spruijt, E.; Bakker, H.E.; Kodger, T.E.; Sprakel, J.H.B.; Stuart, M.A.C.; Gucht, van der J.

    2011-01-01

    We present an experimental study of the fully reversible assembly of oppositely charged colloidal particles in aqueous solutions. Our polystyrene colloids are charged by a grafted polyelectrolyte brush on their surface and stabilized at all salt concentrations by a neutral adsorbed polymer layer. Be

  17. Sand Filter for Rainfall Water with Reverse Flow

    OpenAIRE

    Hilton Ruoso Junior; Pedro Daniel da Cunha Kemerich; Afranio Almir Righes

    2010-01-01

    The use of drinking water in activities that require no potable water is a waste of resources that could be avoided by using clean water, as the rainfall water. This procedure saves the amount spend on toilet discharges in washing cars, sidewalks, clothes and general irrigation as well as on the reduction of floods, helping to minimize environmental impacts on urban areas. This work aims to design, develop and test a sand filter to retain solid waste material from the rain water, allowing the...

  18. Joint AOT-Single Scattering Albedo Retrieval in Algorithm MAIAC

    Science.gov (United States)

    Lyapustin, A.

    2015-12-01

    Multi-Angle Implementation of Atmospheric Correction (MAIAC) is a new algorithm which uses time series analysis and processing of groups of pixels for advanced cloud detection and retrieval of aerosol and surface bidirectional reflectance properties. MAIAC C6+ re-processing of MODIS data record, scheduled to begin in November 2015, will create a suite of products MCD19. Due to high 1km resolution, MAIAC provides information about fine scale aerosol variability required in different applications such as urban air quality analysis. During the past year, we developed a new MAIAC capability to retrieve Single Scattering Albedo (SSA) from MODIS by adapting OMI heritage approach of O. Torres. We will describe MAIAC retrieval approach, AERONET AOT and SSA validation for different world biomass burning regions, and will compare MAIAC results with other sensors.

  19. Validation and empirical correction of MODIS AOT and AE over ocean

    Directory of Open Access Journals (Sweden)

    N. A. J. Schutgens

    2013-09-01

    Full Text Available We present a validation study of Collection 5 MODIS level 2 Aqua and Terra AOT (aerosol optical thickness and AE (Ångström exponent over ocean by comparison to coastal and island AERONET (AErosol RObotic NETwork sites for the years 2003–2009. We show that MODIS (MODerate-resolution Imaging Spectroradiometer AOT exhibits significant biases due to wind speed and cloudiness of the observed scene, while MODIS AE, although overall unbiased, exhibits less spatial contrast on global scales than the AERONET observations. The same behaviour can be seen when MODIS AOT is compared against Maritime Aerosol Network (MAN data, suggesting that the spatial coverage of our datasets does not preclude global conclusions. Thus, we develop empirical correction formulae for MODIS AOT and AE that significantly improve agreement of MODIS and AERONET observations. We show these correction formulae to be robust. Finally, we study random errors in the corrected MODIS AOT and AE and show that they mainly depend on AOT itself, although small contributions are present due to wind speed and cloud fraction in AOT random errors and due to AE and cloud fraction in AE random errors. Our analysis yields significantly higher random AOT errors than the official MODIS error estimate (0.03 + 0.05 τ, while random AE errors are smaller than might be expected. This new dataset of bias-corrected MODIS AOT and AE over ocean is intended for aerosol model validation and assimilation studies, but also has consequences as a stand-alone observational product. For instance, the corrected dataset suggests that much less fine mode aerosol is transported across the Pacific and Atlantic oceans.

  20. Operation, Modeling and Analysis of the Reverse Water Gas Shift Process

    Science.gov (United States)

    Whitlow, Jonathan E.

    2001-01-01

    The Reverse Water Gas Shift process is a candidate technology for water and oxygen production on Mars under the In-Situ Propellant Production project. This report focuses on the operation and analysis of the Reverse Water Gas Shift (RWGS) process, which has been constructed at Kennedy Space Center. A summary of results from the initial operation of the RWGS, process along with an analysis of these results is included in this report. In addition an evaluation of a material balance model developed from the work performed previously under the summer program is included along with recommendations for further experimental work.

  1. Sensory quality of drinking water produced by reverse osmosis membrane filtration followed by remineralisation

    NARCIS (Netherlands)

    Vingerhoeds, M.H.; Nijenhuis, M.A.; Ruepert, N.; Bredie, W.L.P.; Kremer, S.

    2016-01-01

    Membrane filtration of ground, surface, or sea water by reverse osmosis results in permeate, which is almost free from minerals. Minerals may be added afterwards, not only to comply with (legal) standards and to enhance chemical stability, but also to improve the taste of drinking water made from pe

  2. Investigation of microbial communities on reverse osmosis membranes used for process water production

    NARCIS (Netherlands)

    Bereschenko, L.A.; Stams, A.J.M.; Heilig, G.H.J.; Euverink, G.J.W.; Nederlof, M.M.; Loosdrecht, M.C.M.

    2007-01-01

    In the present study, the diversity and the phylogenetic affiliation of bacteria in a biofouling layer on reverse osmosis (RO) membranes were determined. Fresh surface water was used as a feed in a membrane-based water purification process. Total DNA was extracted from attached cells from feed space

  3. Optical Properties of Silica-Encapsulated ZnSe Nanocrystals Prepared with Water-in-Oil Microemulsions

    Science.gov (United States)

    Liu, Kang; Kim, Ji Hyeon; Park, Sang Joon

    2013-01-01

    Silica-encapsulated ZnSe nanocrystals (NCs) were prepared by a safe and simple synthesis method, utilizing a sodium bis (2-ethylhexyl) sulfosuccinate (AOT)/water/cyclohexane microemulsion system and characterized by UV-vis analysis, photoluminescence (PL) spectroscopy, and transmission electron microscopy (TEM). For the encapsulations, two reverse micellar solutions [one for tetraethyl orthosilicate (TEOS) and the other for ZnSe] containing different water volumes were employed. The size of silica particles containing ZnSe NCs could be controlled from 13-37 nm by varying the water content W (W=[H2O]/[AOT]). On the other hand, the size of encapsulated ZnSe NCs was almost unchanged (about 2.5 nm) even though the size of the silica particles was increased. At W = 7, the maximum PL efficiency of 6% was obtained and the photostability was increased markedly after ZnSe NCs were encapsulated by silica.

  4. Integration of Ultrafiltration and Reverse Osmosis on purification of brackish waters: optimization trials

    OpenAIRE

    Travesset Mezquita, Marc

    2012-01-01

    Ultrafiltration (UF), due to its reliability, robustness and stable quality of the water produced , offers technical advantages over conventional pretreatments such as sand filtration coupled with coagulation/flocculation or activated carbon. In this study, the real case of a prototype designed, commissioned and operated consisting of an advanced Ultrafiltration unit (DOW™ UF) followed by a Reverse Osmosis system (Filmtec ™ Reverse Osmosis elements) is evaluated. The work prese...

  5. Polymerization of o-Phenylenediamine Catalyzed by Hemeproteins Encapsulated in Reversed Micelle

    Institute of Scientific and Technical Information of China (English)

    YANG Yong; MAO Lu-yuan; LI Liu-zhu; LIU Xiao-guang; SHI Jun; CAO Shao-kui

    2004-01-01

    Hemeproteins encapsulated in reversed micelle formulated with di-2-ethylhexyl sulfosuccinate (AOT)was found to catalyze the polymerization of o-phenylenediamine (o-PDA) with hydrogen peroxide, whereas o-PDA catalyzed by hemeproteins dissolved in water could only form its trimers. As the nanostructural environment in reversed micelle acts as a certain orientation surrounding medium, it offers a strong electrostatic field that alters the reductive potential of Fe3+/Fe2+ (Em7) in the heme of hemeproteins and thus increases the catalytic activity of peroxidase accordingly. According to the results of UV-Vis, 1H NMR and FTIR, the polymer catalyzed by hemoglobin(Hb) in reversed micelle was presumed to be constructed of lines and trapeziforms alternatively.

  6. Supported lipid bilayer membranes for water purification by reverse osmosis.

    Science.gov (United States)

    Kaufman, Yair; Berman, Amir; Freger, Viatcheslav

    2010-05-18

    Some biological plasma membranes pass water with a permeability and selectivity largely exceeding those of commercial membranes for water desalination using specialized trans-membrane proteins aquaporins. However, highly selective transport of water through aquaporins is usually driven by an osmotic rather mechanical pressure, which is not as attractive from the engineering point of view. The feasibility of adopting biomimetic membranes for water purification driven by a mechanical pressure, i.e., filtration is explored in this paper. Toward this goal, it is proposed to use a commercial nanofiltration (NF) membrane as a support for biomimetic lipid bilayer membranes to render them robust enough to withstand the required pressures. It is shown in this paper for the first time that by properly tuning molecular interactions supported phospholipid bilayers (SPB) can be prepared on a commercial NF membrane. The presence of SPB on the surface was verified and quantified by several spectroscopic and microscopic techniques, which showed morphology close to the desired one with very few defects. As an ultimate test it is shown that hydraulic permeability of the SPB supported on the NF membrane (NTR-7450) approaches the values deduced from the typical osmotic permeabilities of intact continuous bilayers. This permeability was unaffected by the trans-membrane flow of water and by repeatedly releasing and reapplying a 10 bar pressure. Along with a parallel demonstration that aquaporins could be incorporated in a similar bilayer on mica, this demonstrates the feasibility of the proposed approach. The prepared SPB structure may be used as a platform for preparing biomimetic filtration membranes with superior performance based on aquaporins. The concept of SPBs on permeable substrates of the present type may also be useful in the future for studying transport of various molecules through trans-membrane proteins. PMID:20099798

  7. Validation and empirical correction of MODIS AOT and AE over ocean

    OpenAIRE

    N. A. J. Schutgens; Nakata, M; Nakajima, T.

    2013-01-01

    We present a validation study of Collection 5 MODIS level 2 Aqua and Terra AOT (aerosol optical thickness) and AE (Ångström exponent) over ocean by comparison to coastal and island AERONET (AErosol RObotic NETwork) sites for the years 2003–2009. We show that MODIS (MODerate-resolution Imaging Spectroradiometer) AOT exhibits significant biases due to wind speed and cloudiness of the observed scene, while MODIS AE, although overall unbiased, exhibits less spatial contrast on global scales than ...

  8. Determination of sodium bis(2-ethylhexylsulfosuccinate (AOT surfactant with liquid chromatography: Comparative study of evaporative light scattering detector, ultraviolet detector and conductivity detector

    Directory of Open Access Journals (Sweden)

    Ho Ryul Ryu

    2010-03-01

    Full Text Available This work presents comparison of performance of ultraviolet (UV detector, conductivity detector (CD and evaporative light scattering detector (ELSD in terms of quantitative analysis of AOT (sodium bis(2-ethylhexylsulfosuccinate using liquid chromatography. The employed chromatographic condition, including an acetonitrile/water (45:55, v/v isocratic eluent system, is suitable for the three different detectors, and the figures of merits obtained by building up calibration plots are compared. The sensitivities of the detectors are in the order of ELSD ≈ CD >> UV detector. The linear range for quantification of AOT depends on the type of detector: the lower limits are in the order of UV detector (207 ㎍ mL-1 < CD (310 ㎍ mL-1 << ELSD (930 ㎍ mL-1, while the upper limits are 3720 ㎍ mL-1 for all the detectors (the maximum concentration of injected standard solution. The detection limits are 155 ㎍ mL-1 for ELSD, 78 ㎍ mL-1 for UV detector and 13 ㎍ mL-1 for CD, respectively. The figures of merit for each detector could be a guideline in choosing a detector in quantization of AOT. Furthermore, application of the chromatographic method to two commercial products is demonstrated.

  9. Reversible assembly of magnetized particles: Application to water-borne pathogen enumeration

    Science.gov (United States)

    Ramadan, Qasem

    2009-12-01

    Reversible assembly of magnetized particles and cells has been proposed and implemented. The approach is based on magnetized particles or magnetically labeled cell immobilization in an array of individual particle/cell for optical counting. The device has been tested for few types of magnetic particles and one water-borne pathogen: Giardia Lamblia. An individual particle immobilization efficiency of 92% was achieved.

  10. Experiences on sea water reverse osmosis plant at Anuvijay township, Kudankulam Nuclear Power Plant

    International Nuclear Information System (INIS)

    Sea water reverse Osmosis plant SWRO of KKNPP is located at Anuvijay township, Chettikulam, Tirunelveli District, Tamilnadu. The objective of SWRO is to produce 2400 M3 of potable quality water per day. This plant consists of four streams, each having a capacity of 25 M3/hr. Each stream is having 9 pressure tube in parallel and each pressure tube has 6 polyamide spiral wound membrane in series. (author)

  11. Pump reversing water turbine and simplified propeller water turbine; Pump gyakuten suisha kan`i propeller suisha

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-03-10

    As a result of the joint research with the Tokyo Electric Power Co., Meidensha Corp. delivered a pump reversing water turbine and a simplified propeller water turbine to the Ayato power plant. For the purpose of effectively using the water gate-discharged for maintained discharge, the equipment is aimed at reducing construction cost. Therefore, by looking at it from a different angle, the submerged pump reversing water turbine and the outdoor-type distribution panel switchgear were adopted, and no building is needed. 1) Submerged pump reversing water turbine: 223kW-8.062m-3.733m{sup 3}/s; 2) Simplified propeller water turbine: 447kW-7.905m-7.633m{sup 3}/s. As features, the power plant runs the main two turbines alternately at the time of maintained discharge throughout a year, aiming at prolonging the equipment life. The plant runs two turbines at the time of increased discharge, aiming at increasing the output to maximum. (NEDO)

  12. On the impact of water activity on reversal tolerant fuel cell anode performance and durability

    Science.gov (United States)

    Hong, Bo Ki; Mandal, Pratiti; Oh, Jong-Gil; Litster, Shawn

    2016-10-01

    Durability of polymer electrolyte fuel cells in automotive applications can be severely affected by hydrogen starvation arising due to transients during the drive-cycle. It causes individual cell voltage reversal, yielding water electrolysis and carbon corrosion reactions at the anode, ultimately leading to catastrophic cell failure. A popular material-based mitigation strategy is to employ a reversal tolerant anode (RTA) that includes oxygen evolution reaction (OER) catalyst (e.g., IrO2) to promote water electrolysis over carbon corrosion. Here we report that RTA performance surprisingly drops under not only water-deficient but also water-excess conditions. This presents a significant technical challenge since the most common triggers for cell reversal involve excess liquid water. Our findings from detailed electrochemical diagnostics and nano-scale X-ray computed tomography provide insight into how automotive fuel cells can overcome critical vulnerabilities using material-based solutions. Our work also highlights the need for improved materials, electrode designs, and operation strategies for robust RTAs.

  13. Rejection of Emerging Organic Contaminants by Nanofiltration and Reverse Osmosis Membranes: Effects of Fouling, Modelling and Water Reuse

    NARCIS (Netherlands)

    Yangali Quintanilla, V.

    2010-01-01

    The book contains a description of the presence of micropollutants (medicines, hormones, pesticides) in surface water and shows that conventional water treatment poorly removes micropollutants. Nanofiltration and reverse osmosis are more appropriate technologies; however removals can vary depending

  14. Effect of water matrices on removal of veterinary pharmaceuticals by nanofiltration and reverse osmosis membranes

    Institute of Scientific and Technical Information of China (English)

    Davor Dolar; Arna Vukovi(c); Danijela A(a)perger; Kre(s)imir Ko(s)ulti(c)

    2011-01-01

    This study explored the removal of five veterinary pharmaceuticals (VPs) (sulfamethoxazole (SMETOX),trimethopfim (TMP),ciprofloxacin (CIPRO),dexamethasone (DEXA) and febantel (FEBA)) from different water matrices (Milli-Q water,model water,tap water and real pharmaceutical wastewater using four types of nanofiltration (NF) membranes (NF90,NF270,NF and HL) and two reverse osmosis (RO) membranes (LFC-1 and XLE).All VPs were added to different water matrices at a concentration of 10 mg/L.Rejections of VPs and water flux were measured.The rejection increased with increase of molecular weight.The highest rejections were obtained with RO membranes (LFC-1,XLE) and tight NF (NF90) membrane.In general,the rejection of VPs was higher in model water and tap water than in Milli-Q water,but the water flux was lower.This was mainly explained by ion adsorption inside the membranes pores.Narrower pore size counteracted the effect of presence of low concentration of natural organic matter (NOM) in tap water.The NOM was assumed to enhance the adsorption of VPs onto membrane surface,increased the size exclusion and electrostatic repulsion also appeared during the transport.Investigated water matrices had influence on water flux decline due to their complexity.

  15. Sensory quality of drinking water produced by reverse osmosis membrane filtration followed by remineralisation.

    Science.gov (United States)

    Vingerhoeds, Monique H; Nijenhuis-de Vries, Mariska A; Ruepert, Nienke; van der Laan, Harmen; Bredie, Wender L P; Kremer, Stefanie

    2016-05-01

    Membrane filtration of ground, surface, or sea water by reverse osmosis results in permeate, which is almost free from minerals. Minerals may be added afterwards, not only to comply with (legal) standards and to enhance chemical stability, but also to improve the taste of drinking water made from permeate. Both the nature and the concentrations of added minerals affect the taste of the water and in turn its acceptance by consumers. The aim of this study was to examine differences in taste between various remineralised drinking waters. Samples selected varied in mineral composition, i.e. tap water, permeate, and permeate with added minerals (40 or 120 mg Ca/L, added as CaCO3, and 4 or 24 mg Mg/L added as MgCl2), as well as commercially available bottled drinking waters, to span a relevant product space in which the remineralised samples could be compared. All samples were analysed with respect to their physical-chemical properties. Sensory profiling was done by descriptive analysis using a trained panel. Significant attributes included taste intensity, the tastes bitter, sweet, salt, metal, fresh and dry mouthfeel, bitter and metal aftertaste, and rough afterfeel. Total dissolved solids (TDS) was a major determinant of the taste perception of water. In general, lowering mineral content in drinking water in the range examined (from water from fresh towards bitter, dry, and rough sensations. In addition, perceived freshness of the waters correlated positively with calcium concentration. The greatest fresh taste was found for water with a TDS between 190 and 350 mg/L. Remineralisation of water after reverse osmosis can improve drinking quality significantly.

  16. Unexpected increasing AOT trends over northwest Bay of Bengal in the early postmonsoon season

    Energy Technology Data Exchange (ETDEWEB)

    Kishcha, P.; Starobinets, B.; Long, Charles N.; Alpert, P.

    2012-12-13

    The main point of our study is that aerosol trends can be created by changes in meteorology without changes in aerosol source strength. Over the 10 year period 2000–2009, in October, Moderate Resolution Imaging Spectroradiometer (MODIS) showed strong increasing aerosol optical thickness (AOT) trends of approximately 14% yr-1 over northwest Bay of Bengal (BoB) in the absence of AOT trends over the east of the Indian subcontinent. This was unexpected because sources of anthropogenic pollution were located over the Indian subcontinent and aerosol transport from the Indian subcontinent to northwest BoB was carried out by prevailing winds. In October, winds over the east of the Indian subcontinent were stronger than winds over northwest BoB, which resulted in wind convergence and accumulation of aerosol particles over northwest BoB. Moreover, there was an increasing trend in wind convergence over northwest BoB. This led to increasing trends in the accumulation of aerosol particles over northwest BoB and, consequently, to strong AOT trends over this area. In contrast to October, November showed no increasing AOT trends over northwest BoB or the nearby Indian subcontinent. The lack of AOT trends over northwest BoB corresponds to a lack of trends in wind convergence in that region. Finally, December domestic heating by the growing population resulted in positive AOT trends of similar magnitude over land and sea. Our findings illustrate that in order to explain and predict trends in regional aerosol loading, meteorological trends should be taken into consideration together with changes in aerosol source strength.

  17. EFFICIENCY OF DOMESTIC REVERSE OSMOSIS IN REMOVAL OF TRIHALOMETHANES FROM DRINKING WATER

    Directory of Open Access Journals (Sweden)

    S. Mazloomi ، R. Nabizadeh ، S. Nasseri ، K. Naddafi ، S. Nazmara ، A. H. Mahvi

    2009-10-01

    Full Text Available The reaction of disinfectants with natural organic matters existing in water lead to the formation of Disinfection By-Products. Potentially hazardous and carcinogenic characteristics of trihalomethanes (THMs are recognized. Thus removal of THMs or its precursors are necessary for human health. The aim of this study was to study the efficiency of domestic reverse osmosis (RO in removal of trihalomethanes from drinking water. A pilot scale of RO system with Polyamide membrane as Spiral-Wound, Tape wrapping module was used. Feed solution was made by using of pure chloroform. The samples containing chloroform were analyzed using a gas chromatograph equipped with a flame ionization detector. By increasing the flow, the removal rate of chloroform decreased and with declining removal of EC, the removal of chloroform declined too. In this research, at the worst condition, the efficiency of the pilot scale reverse osmosis reached to 80 % removal of chloroform.

  18. Influence of sodium bis(2-ethylhexyl) sulfosuccinate (AOT) on zinc electrodeposition

    Energy Technology Data Exchange (ETDEWEB)

    Lehr, I.L. [Instituto de Ingenieria Electroquimica y Corrosion (INIEC), Departamento de Ingenieria Quimica, Universidad Nacional del Sur, Av. Alem 1253, 8000 Bahia Blanca (Argentina); Saidman, S.B., E-mail: ssaidman@criba.edu.ar [Instituto de Ingenieria Electroquimica y Corrosion (INIEC), Departamento de Ingenieria Quimica, Universidad Nacional del Sur, Av. Alem 1253, 8000 Bahia Blanca (Argentina)

    2012-03-01

    This work is a study of the electrodeposition of zinc onto SAE 4140 steel electrodes using solutions containing zinc sulfate and bis(2-ethylhexyl) sodium sulfosuccinate (AOT). The influence of different parameters such as electrolyte concentration, electrodeposition time and temperature on the morphology of the electrodeposits was analyzed. The deposits were characterized by scanning electron microscopy (SEM), energy dispersive X-ray (EDX) and X-ray diffraction. The variation of open circuit potential over time in chloride solutions was also evaluated. The nucleation-growth process and consequently the morphology of the electrodeposits are modified in the presence of AOT. The surfactant induces the formation of a porous deposit.

  19. Sensory quality of drinking water produced by reverse osmosis membrane filtration followed by remineralisation

    DEFF Research Database (Denmark)

    Vingerhoeds, Monique H.; Nijenhuis-de Vries, Mariska A.; Ruepert, Nienke;

    2016-01-01

    permeate. Both the nature and the concentrations of added minerals affect the taste of the water and in turn its acceptance by consumers. The aim of this study was to examine differences in taste between various remineralised drinking waters.Samples selected varied in mineral composition, i.e. tap water...... to their physical-chemical properties. Sensory profiling was done by descriptive analysis using a trained panel.Significant attributes included taste intensity, the tastes bitter, sweet, salt, metal, fresh and dry mouthfeel, bitter and metal aftertaste, and rough afterfeel. Total dissolved solids (TDS) was a major......Membrane filtration of ground, surface, or sea water by reverse osmosis results in permeate, which is almost free from minerals. Minerals may be added afterwards, not only to comply with (legal) standards and to enhance chemical stability, but also to improve the taste of drinking water made from...

  20. Effects of Morphology of Cerium Oxide Catalysts for Reverse Water Gas Shift Reaction

    OpenAIRE

    Kovasevic, M.; Mojet, B.L.; Ommen, van, B.; Lefferts, L.

    2016-01-01

    Reverse water gas shift reaction (RWGS) was investigated over cerium oxide catalysts of distinct morphologies: cubes, rods and particles. Catalysts were characterized by X-ray diffraction, Raman spectroscopy and temperature programmed reduction (TPR) in hydrogen. Nanoshapes with high concentration of oxygen vacancies contain less surface oxygen removable in TPR. Cerium oxide cubes exhibited two times higher activity per surface area as compared to rods and particles. Catalytic activity of the...

  1. Water permeability of nanoporous graphene at realistic pressures for reverse osmosis desalination

    Energy Technology Data Exchange (ETDEWEB)

    Cohen-Tanugi, David; Grossman, Jeffrey C. [Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

    2014-08-21

    Nanoporous graphene (NPG) shows tremendous promise as an ultra-permeable membrane for water desalination thanks to its atomic thickness and precise sieving properties. However, a significant gap exists in the literature between the ideal conditions assumed for NPG desalination and the physical environment inherent to reverse osmosis (RO) systems. In particular, the water permeability of NPG has been calculated previously based on very high pressures (1000–2000 bars). Does NPG maintain its ultrahigh water permeability under real-world RO pressures (<100 bars)? Here, we answer this question by drawing results from molecular dynamics simulations. Our results indicate that NPG maintains its ultrahigh permeability even at low pressures, allowing a permeate water flux of 6.0 l/h-bar per pore, or equivalently 1041 ± 20 l/m{sup 2}-h-bar assuming a nanopore density of 1.7 × 10{sup 13} cm{sup −2}.

  2. Nanofiltration in Transforming Surface Water into Healthy Water: Comparison with Reverse Osmosis

    OpenAIRE

    Naidu, L. D.; Saravanan, S.; Chidambaram, M.; Mukesh Goel; Ashutosh Das; J. Sarat Chandra Babu

    2015-01-01

    The natural surface water, especially available through rivers, is the main source of healthy water for the living beings throughout the world from ancient days as it consists of all essential minerals. With the advent of industrialization, gradually even the most prominent rivers have been polluted in all parts of the world. Although there are lots of technologies, nanofiltration (NF) has been chosen to transform river water into healthy water due to its unique advantages of retaining optimu...

  3. Indirect desalination of Red Sea water with forward osmosis and low pressure reverse osmosis for water reuse

    KAUST Repository

    Yangali-Quintanilla, Victor

    2011-10-01

    The use of energy still remains the main component of the costs of desalting water. Forward osmosis (FO) can help to reduce the costs of desalination, and extracting water from impaired sources can be beneficial in this regard. Experiments with FO membranes using a secondary wastewater effluent as a feed water and Red Sea water as a draw solution demonstrated that the technology is promising. FO coupled with low pressure reverse osmosis (LPRO) was implemented for indirect desalination. The system consumes only 50% (~1.5 kWh/m3) of the energy used for high pressure seawater RO (SWRO) desalination (2.5-4 kWh/m3), and produces a good quality water extracted from the impaired feed water. Fouling of the FO membranes was not a major issue during long-term experiments over 14 days. After 10 days of continuous FO operation, the initial flux declined by 28%. Cleaning the FO membranes with air scouring and clean water recovered the initial flux by 98.8%. A cost analysis revealed FO per se as viable technology. However, a minimum average FO flux of 10.5 L/m2-h is needed to compete with water reuse using UF-LPRO, and 5.5 L/m2-h is needed to recover and desalinate water at less cost than SWRO. © 2011 Elsevier B.V.

  4. Nanofiltration in Transforming Surface Water into Healthy Water: Comparison with Reverse Osmosis

    Directory of Open Access Journals (Sweden)

    L. D. Naidu

    2015-01-01

    Full Text Available The natural surface water, especially available through rivers, is the main source of healthy water for the living beings throughout the world from ancient days as it consists of all essential minerals. With the advent of industrialization, gradually even the most prominent rivers have been polluted in all parts of the world. Although there are lots of technologies, nanofiltration (NF has been chosen to transform river water into healthy water due to its unique advantages of retaining optimum TDS (with essential minerals required for human body, consuming of lower energy, and no usage of any chemicals. The prominent parameters of surface water and macro/microminerals of treated water have been analyzed. It is shown that NF is better in producing healthy water with high flux by consuming low energy.

  5. Effect of water temperature on biofouling development in reverse osmosis membrane systems

    KAUST Repository

    Farhat, N.M.

    2016-07-14

    Understanding the factors that determine the spatial and temporal biofilm development is a key to formulate effective control strategies in reverse osmosis membrane systems for desalination and wastewater reuse. In this study, biofilm development was investigated at different water temperatures (10, 20, and 30 °C) inside a membrane fouling simulator (MFS) flow cell. The MFS studies were done at the same crossflow velocity with the same type of membrane and spacer materials, and the same feed water type and nutrient concentration, differing only in water temperature. Spatially resolved biofilm parameters such as oxygen decrease rate, biovolume, biofilm spatial distribution, thickness and composition were measured using in-situ imaging techniques. Pressure drop (PD) increase in time was used as a benchmark as to when to stop the experiments. Biofilm measurements were performed daily, and experiments were stopped once the average PD increased to 40 mbar/cm. The results of the biofouling study showed that with increasing feed water temperature (i) the biofilm activity developed faster, (ii) the pressure drop increased faster, while (iii) the biofilm thickness decreased. At an average pressure drop increase of 40 mbar/cm over the MFS for the different feed water temperatures, different biofilm activities, structures, and quantities were found, indicating that diagnosis of biofouling of membranes operated at different or varying (seasonal) feed water temperatures may be challenging. Membrane installations with a high temperature feed water are more susceptible to biofouling than installations fed with low temperature feed water.

  6. Effect of water temperature on biofouling development in reverse osmosis membrane systems.

    Science.gov (United States)

    Farhat, N M; Vrouwenvelder, J S; Van Loosdrecht, M C M; Bucs, Sz S; Staal, M

    2016-10-15

    Understanding the factors that determine the spatial and temporal biofilm development is a key to formulate effective control strategies in reverse osmosis membrane systems for desalination and wastewater reuse. In this study, biofilm development was investigated at different water temperatures (10, 20, and 30 °C) inside a membrane fouling simulator (MFS) flow cell. The MFS studies were done at the same crossflow velocity with the same type of membrane and spacer materials, and the same feed water type and nutrient concentration, differing only in water temperature. Spatially resolved biofilm parameters such as oxygen decrease rate, biovolume, biofilm spatial distribution, thickness and composition were measured using in-situ imaging techniques. Pressure drop (PD) increase in time was used as a benchmark as to when to stop the experiments. Biofilm measurements were performed daily, and experiments were stopped once the average PD increased to 40 mbar/cm. The results of the biofouling study showed that with increasing feed water temperature (i) the biofilm activity developed faster, (ii) the pressure drop increased faster, while (iii) the biofilm thickness decreased. At an average pressure drop increase of 40 mbar/cm over the MFS for the different feed water temperatures, different biofilm activities, structures, and quantities were found, indicating that diagnosis of biofouling of membranes operated at different or varying (seasonal) feed water temperatures may be challenging. Membrane installations with a high temperature feed water are more susceptible to biofouling than installations fed with low temperature feed water.

  7. Reverse micelles as suitable microreactor for increased biohydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Pandey, Anjana [Nanotechnology and Molecular Biology Laboratory, Centre of Biotechnology, University of Allahabad, Allahabad 211002 (India); Pandey, Ashutosh [Centre of Energy Studies, MNNIT, Allahabad 211004 (India)

    2008-01-15

    Reverse micelles have been shown to act as efficient microreactors for enzymic reactions and whole cell entrapment in organic (non-aqueous) media wherein the reactants are protected from denaturation by the surrounding organic solvent. These micelles are thermodynamically stable, micrometer sized water droplets dispersed in an organic phase by a surfactant. It has been observed that when whole cells of photosynthetic bacteria (Rhodopseudomonas sphaeroides or Rhodobacter sphaeroides 2.4.1) are entrapped inside these reverse micelles, the H{sub 2} production enhanced from 25 to 35 folds. That is, 1.71mmol(mgprotein){sup -1}h{sup -1} in case of R. sphaeroides which is 25 fold higher in benzene-sodium lauryl sulfate reverse micelles. Whereas, in case of R. sphaeroides 2.4.1 the H{sub 2} production was increased by 35 fold within AOT-isooctane reverse micelles i.e. 11.5mmol(mgprotein){sup -1}h{sup -1}. The observations indicate that the entrapment of whole cells of microbes within reverse micelles provides a novel and efficient technique to produce hydrogen by the inexhaustible biological route. The two microorganisms R. sphaeroides 2.4.1 (a photosynthetic bacteria) and Citrobacter Y19 (a facultative anaerobic bacteria) together are also entrapped within AOT-isooctane and H{sub 2} production was measured i.e. 69mmol(mgprotein){sup -1}h{sup -1}. The nitrogenase enzyme responsible for hydrogen production by R. sphaeroides/R. sphaeroides 2.4.1 cells is oxygen sensitive, and very well protected within reverse micelles by the use of combined approach of two cells (R. sphaeroides 2.4.1 and Citrobacter Y19). In this case glucose present in the medium of Citrobacter Y19 serves double roles in enhancing the sustained production rate of hydrogen. Firstly, it quenches the free O{sub 2}liberated as a side product of reaction catalyzed by nitrogenase, which is O{sub 2} labile. Secondly, organic acid produced by this reaction is utilized by the Citrobacter Y19 as organic substrate in

  8. Determination of water states and the structural parameters of W/O microemulsions

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The states of water in sodium bis(2-ethylhexyl) sulfosuccinate (AOT)/isooctane/water reverse(W/O) microemulsions system have been investigated by using Fourier transform infrared spectroscopy(FT-IR) technique. The broad peak obtained for hydroxy(O-H) of water has been resolved by least square curve-fitting. It has been observed that the water solubilized in microemulsion droplets has four states, i.e. bound water with sulfo-group, free water, bound water with sodium counterion in the water pool of microemulsion droplets and a small amount of trapped water in the palisade layer of microemulsion droplets. The following have also been determined: the aggregation number (n), the radius of the water pool in the microemulsions(rw), the thickness of the bound water with sulfo-group(d1), the thickness of the bound water with sodium counterion(d2), the total thickness of the bound water ( d ) and the effective area of head groups of AOT(AAOT).

  9. The effect of flow and chemical corrosion in reverse osmosis over desalinated water

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Young Jae [Chunnam National Univ., Gwangju (Korea, Republic of); Pak, Byung Gu [Doosan Heavy Industry Co., Tongyoung (Korea, Republic of)

    2015-12-15

    Desalinated water produced by a reverse osmosis (RO) filtering method forms about 22% of total production of desalinated water in the world. However, the RO environment is very corrosive due to the presence of various chemicals for water treatment and the flow of sand particles leading to corrosion. Recently, there has been much effort to substitute cheaper and more corrosion resistant stainless steels for copper based alloys as a valve material in RO. Nevertheless, the effects of chemicals and particles on the corrosion of stainless steels have rarely been studied. Erosion phenomenon was detected under the condition with the flow rate of more than 8ms{sup -1} in spite of the absence of sand particles. In seawater containing sand particles, the erosion in stainless steels was accelerated further.

  10. Dynamics of water and solute transport in polymeric reverse osmosis membranes via molecular dynamics simulations

    CERN Document Server

    Shen, Meng; Lueptow, Richard M

    2016-01-01

    The Angstrom-scale transport characteristics of water and six different solutes, methanol, ethanol, 2-propanol, urea, Na+, and Cl-, were studied for a polyamide reverse osmosis (RO) membrane, FT-30, using non-equilibrium molecular dynamics (NEMD) simulations. Results indicate that water transport increases with an increasing fraction of connected percolated free volume, or water-accessible open space, in the membrane polymer structure. This free volume is enhanced by the dynamic structure of the membrane at the molecular level as it swells when hydrated and vibrates due to molecular collisions allowing a continuous path connecting the opposite membrane surfaces. The tortuous paths available for transport of solutes result in Brownian motion of solute molecules and hopping from pore to pore as they pass through the polymer network structure of the membrane. The transport of alcohol solutes decreases for solutes with larger Van der Waals volume, which corresponds to less available percolated free volume, or sol...

  11. TR-ESR Investigation on Reaction of Vitamin C with Excited Triplet of 9,10-phenanthrenequinone in Reversed Micelle Solutions

    Science.gov (United States)

    Xu, Xin-sheng; Shi, Lei; Liu, Yi; Ji, Xue-han; Cui, Zhi-feng

    2011-04-01

    Time-resolved electron spin resonance has been used to study quenching reactions between the antioxidant Vitamin C (VC) and the triplet excited states of 9,10-phenanthrenequinone (PAQ) in ethylene glycol-water (EG-H2O) homogeneous and inhomogeneous reversed micelle solutions. Reversed micelle solutions were used to be the models of physiological environment of biological cell and tissue. In PAQ/EG-H2O homogeneous solution, the excited triplet of PAQ (3PAQ*) abstracts hydrogen atom from solvent EG. In PAQ/VC/EG-H2O solution, 3PAQ* abstracts hydrogen atom not only from solvent EG but also from VC. The quenching rate constant of 3PAQ* by VC is close to the diffusion-controlled value of 1.41 × 108 L/(mol ·s). In hexadecyltrimethylammonium bromide (CTAB)/EG-H2O and aerosol OT (AOT)/EG-H2O reversed micelle solutions, 3PAQ* and VC react around the water-oil interface of the reversed micelle. Exit of 3PAQ* from the lipid phase slows down the quenching reaction. For Triton X-100 (TX-100)/EG-H2O reversed micelle solution, PAQ and VC coexist inside the hydrophilic polyethylene glycol core, and the quenching rate constant of 3PAQ* by VC is larger than those in AOT/EG-H2O and CTAB/EG-H2O reversed micelle solutions, even a little larger than that in EG-H2O homogeneous solution. The strong emissive chemically induced dynamic electron polarization of As.- resulted from the effective TM spin polarization transfer in hydrogen abstraction of 3PAQ* from VC.

  12. Integrating tunable anion exchange with reverse osmosis for enhanced recovery during inland brackish water desalination.

    Science.gov (United States)

    Smith, Ryan C; SenGupta, Arup K

    2015-05-01

    For inland brackish water desalination by reverse osmosis or RO, concentrate or reject disposal poses a major challenge. However, enhanced recovery and consequent reduction in the reject volume using RO processes is limited by the solubility of ions present in the feedwater. One of the most common and stubborn precipitate formed during desalination is calcium sulfate. Reducing or eliminating the presence of sulfate would allow the process to operate at higher recoveries without threat to membrane scaling. In this research, this goal is accomplished by using an appropriate mixture of self-regenerating anion exchange resins that selectively remove and replace sulfate by chloride prior to the RO unit. Most importantly, the mixed bed of anion exchange resins is self-regenerated with the reject brine from the RO process, thus requiring no addition of external chemicals. The current work demonstrates the reversibility of the hybrid ion exchange and RO (HIX-RO) process with 80% recovery for a brackish water composition representative of groundwater in San Joaquin Valley in California containing approximately 5200 mg/L of total dissolved solids or TDS. Consequently, the reject volume can be reduced by 50% without the threat of sulfate scaling and use of antiscaling chemicals can be eliminated altogether. By appropriately designing or tuning the mixed bed of anion exchange resins, the process can be extended to nearly any composition of brackish water for enhanced recovery and consequent reduction in the reject volume.

  13. Comparison of methods for assessing reverse osmosis membrane treatment of shrimp process water.

    Science.gov (United States)

    Casani, Sandra; Hansen, Tina B; Christensen, Jakob; Knøchel, Susanne

    2005-04-01

    Interest in reuse of process water from the food industry has reinforced the importance of controlling and monitoring the effectiveness and reliability of treatment systems regarding removal of organic matter and microorganisms. The ability of adenosine triphosphate bioluminescence, conductivity, turbidometry, absorbance, and multichannel fluorescence spectroscopy for indirectly monitoring the integrity of a reverse osmosis membrane when treating process water recovered from peeling in a shrimp processing line was evaluated. This study demonstrated that reverse osmosis was capable of removing bacteria (ca. 7 log CFU ml(-1)) to the levels required by the regulatory authorities for water recycling within the same food unit operation. Adenosine triphosphate and turbidometry showed a higher sensitivity for detecting compromising conditions at the treatment system (0.1% concentration of feed in permeate) and a better correlation with the aerobic count at lower levels than the other methods investigated. The sensitivity for assessing membrane integrity of conductivity and multichannel fluorescence was 1% of feed in permeate. Impact of feed variations was best leveled out in the permeates for turbidity measurements. Multichannel fluorescence spectroscopy may require laborious calibration procedures and expertise regarding data analysis and interpretation of results, which are not always available in food industries. Absorbance did not respond to changes in membrane integrity and was not well correlated to the aerobic count because of the poor sensitivity of this method for these purposes.

  14. Mechanisms of Cytochrome C Extraction by Reverse Micelles

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The extraction of cytochrome C was carried out by means of phase transfer technique with three different reverse micellar systems, i.e., a CTAB micellar solution in n-butyl alcohol-chloroform(volume ratio 4∶1), an AOT micellar solution in isooctane and a SDSS-D2EHPA micellar solution in isooctane. The extraction mechanisms were studied. The results show that the extraction mechanisms for the same proteins with different types of reverse micellar systems can be distinct. The extraction of cytochrome C with CTAB and SDSS-D2EHPA reverse micellar systems are carried out according to the mechanism of electrostatic interaction. However, in the extraction of cytochrome C with the AOT reverse micellar system, the electrostatic interaction between the protein and the surfactant is not important.

  15. Pseudomonas-related populations associated with reverse osmosis in drinking water treatment.

    Science.gov (United States)

    Sala-Comorera, Laura; Blanch, Anicet R; Vilaró, Carles; Galofré, Belén; García-Aljaro, Cristina

    2016-11-01

    Reverse osmosis membrane filtration technology (RO) is used to treat drinking water. After RO treatment, bacterial growth is still observed in water. However, it is not clear whether those microorganisms belong to species that can pose a health risk, such as Pseudomonas spp. The goal of this study is to characterize the bacterial isolates from a medium that is selective for Pseudomonas and Aeromonas which were present in the water fraction before and after the RO. To this end, isolates were recovered over two years and were identified by matrix-assisted laser desorption/ionization-time of flight mass spectrometry. They were then biochemically phenotyped and the population similarity indexes were calculated. The isolates were analysed for their capacity to form biofilms in vitro and antimicrobial susceptibility. There were significant differences between the microbial populations in water before and after RO. Furthermore, the structures of the populations analysed at the same sampling point were similar in different sampling campaigns. Some of the isolates had the capacity to form a biofilm and showed resistance to different antibiotics. A successful level filtration via RO and subsequent recolonization of the membrane with different species from those in the feed water was found. Pseudomonas aeruginosa was not recovered from among the isolates. This study increases the knowledge on the microorganisms present in water after RO treatment, with focus in one of the genus causing problems in RO systems associated with human health risk, Pseudomonas.

  16. Use of water processed by reverse osmosis For vapor generation in tobacco industry

    Directory of Open Access Journals (Sweden)

    Carlos Alberto Klimeck Gouvea

    2012-06-01

    Full Text Available This article presents a study due to the technical use of reverse osmosis to treat the boiler water for steam generation in a plant of tobacco processing in Santa Catarina, Brazil. The monitoring was conducted between the years 2006 to 2008, presenting the results concerning the improvement of water quality with emphasis on environmental and financial gains. Water quality can be observed by the reduction of 90% in silica content and 100% hardness, leading to a reduction of incrustation and corrosion of the system. Moreover, a reduction in the discharges water from the boiler volume reduced the water consumption by approximately 6,000 m3/year and also the consumption of chemicals used in wastewater treatment plant, with a reduction of 32.76 m3/day of effluents to treatment. The reducing of energy with natural gas for water heating replacement was almost 900,000 m3/year (19.45%, because of increased in heat exchange efficiency. The reducing in the CO2 emissions was in order of 1215,65 t/year. Finally, based on the achieved results obtained, can be possible to assume a reducing costs of production as a whole.

  17. Biological support media influence the bacterial biofouling community in reverse osmosis water reclamation demonstration plants.

    Science.gov (United States)

    Ferrera, Isabel; Mas, Jordi; Taberna, Elisenda; Sanz, Joan; Sánchez, Olga

    2015-01-01

    The diversity of the bacterial community developed in different stages of two reverse osmosis (RO) water reclamation demonstration plants designed in a wastewater treatment plant (WWTP) in Tarragona (Spain) was characterized by applying 454-pyrosequencing of the 16S rRNA gene. The plants were fed by secondary treated effluent to a conventional pretreatment train prior to the two-pass RO system. Plants differed in the material used in the filtration process, which was sand in one demonstration plant and Scandinavian schists in the second plant. The results showed the presence of a highly diverse and complex community in the biofilms, mainly composed of members of the Betaproteobacteria and Bacteroidetes in all stages, with the presence of some typical wastewater bacteria, suggesting a feed water origin. Community similarities analyses revealed that samples clustered according to filter type, highlighting the critical influence of the biological supporting medium in biofilm community structure.

  18. Nanofiltration vs. reverse osmosis for the removal of emerging organic contaminants in water reuse

    KAUST Repository

    Yangali-Quintanilla, Victor

    2011-10-01

    Reverse osmosis (RO) in existing water reuse facilities is a water industry standard. However, that approach may be questioned taking into consideration that "tight" NF can be equal or "better" than RO. NF can achieve the same removals of RO membranes when dealing with emerging organic contaminants (pharmaceuticals, pesticides, endocrine disruptors and others). Experiments using 18 emerging contaminants were performed using membranes NF200 and NF90 at bench-scale units, and for a more complete study, results of NF and RO pilot and full-scale experiments where compared to our experimental results. The removal results showed that NF can remove many emerging contaminants. The average removal by tight NF was 82% for neutral contaminants and 97% for ionic contaminants. The average removal by RO was 85% for neutral contaminants and 99% for ionic contaminants. Aquifer recharge and recovery (ARR) followed by NF can effectively remove emerging contaminants with removals over 90% when loose NF membranes are used.

  19. Comparison of tertiary treatment by nanofiltration and reverse osmosis for water reuse in denim textile industry.

    Science.gov (United States)

    Ben Amar, Nihel; Kechaou, Noura; Palmeri, John; Deratani, André; Sghaier, Ali

    2009-10-15

    The wastewaters resulting from different baths of a dyeing factory specialized in denim fabric are collected and treated by an activated sludge plant. This study investigated the coupling of activated sludge treatment with either nanofiltration (NF) or reverse osmosis (RO) to recycle water and reuse it in the process. We first conducted NF experiments with a HL membrane in different configurations: dead end and cross-flow for flat sheets and also in spiral wound form. Results on water permeation and salt rejection show that performances are configuration dependent. Then, for the study of the NF/RO textile wastewater treatment, experiments were conducted with spiral wound membranes in order to be closest to the industrial configuration. After analyzing the removal efficiencies of suspended solids and chemical oxygen demand (COD) of the treatment plant, we conducted NF experiments using an HL2514TF spiral wound membrane preceded by ultrafiltration (UF) treatment. We used as well an RO membrane (AG2514TF) to compare performances in water yield and quality for the same pumping costs. The results show that NF allows higher yield, while respecting the Tunisian standard of water reuse (CODreuse of the water in the process.

  20. A comparative study of boron and arsenic (III) rejection from brackish water by reverse osmosis membranes

    KAUST Repository

    Teychene, Benoît

    2013-02-01

    This study aims to compare at lab-scale the rejection efficiency of several reverse osmosis membranes (RO) toward arsenic (III) and boron during the filtration of a synthetic brackish water. The effect of pH and operating conditions on the rejection of each RO membrane was studied. Two types of membrane were investigated: "brackish water" and "sea water" membranes. Our results showed that the metalloid rejection depends on the membrane type, pH and transmembrane pressure applied. Increasing pH above the dissociation constant (pKa) of each specie improves significantly the metalloid rejection by RO membranes, whatever the membrane type. Moreover, at identical operating conditions (pH, transmembrane pressure), results showed that the brackish water membranes have a higher water flux and exhibit lower metalloid rejection. The highest As(III) rejection value for the tested brackish water membranes was 99% obtained at pH = 9.6 and 40 bars, whereas it was found that the sea water RO membranes could highly reject As(III), more than 99%, even at low pH and low pressure (pH = 7.6 and 24 bars).Regarding Boron rejection, similar conclusions could be drawn. The sea water RO membranes exert higher removal, with a high rejection value above 96% over the tested conditions. More generally, this study showed that, whatever the operating conditions or the tested membranes, the boron and As(III) permeate concentrations are below the WHO guidelines. In addition, new data about the boron and arsenic permeability of each tested RO membrane was brought thanks to a theoretical calculation. © 2012 Elsevier B.V.

  1. Preparation and water desalination properties of POSS-polyamide nanocomposite reverse osmosis membranes

    KAUST Repository

    Duan, Jintang

    2015-01-01

    The application of nanotechnology to thin-film nanocomposites (TFN) is a new route to enhance membrane performance in water desalination. Here, the potential of polyhedral oligomeric silsesquioxane (POSS) as the nanofiller in polyamide (PA) reverse osmosis membranes was systematically investigated. Four POSS materials (P-8Phenyl, P-8NH3Cl, P-8NH2 and P-1NH2) were introduced into the selective layer by physical blending or chemical fixation during standard interfacial polymerization. Water flux and NaCl rejection were measured with 2000ppm NaCl solution under 15.5bar pressure, and SEM and TEM images of membrane selective layers were obtained. Membranes prepared without POSS showed water flux of 20.0±0.5L/m2·h and salt rejection of 98.0±0.2%. TFN membranes prepared with 0.4% (w/v) P-8Phenyl in the organic phase showed a 65% increase in water flux compared to the pristine PA membrane while maintaining high salt rejection. The selective layer of this membrane maintained the typical ridge-and-valley structure of aromatic PA. Results with P-8NH3Cl and P-8NH2 added to the organic phase were similar. TFN membranes prepared with monoamine P-1NH2 in the organic phase had poor water flux of 3.2L/m2·h, a smooth and more hydrophobic surface, and a much thicker (~400nm) selective layer. One of the four POSS compounds studied, P-8NH3Cl, is sufficiently soluble in water for incorporation into the selective layer via the aqueous phase. Membranes were prepared with P-8NH3Cl in the aqueous phase at varying reaction time, loading, and additive (triethylamine) concentration. With these parameters optimized, water flux increased to 35.4L/m2·h.

  2. Sulfonsuccinate (AOT Capped Pure and Mn-Doped CdS Nanoparticles

    Directory of Open Access Journals (Sweden)

    D. Venkatesan

    2012-01-01

    Full Text Available CdS nanoparticles and thin films are well known for their excellent semiconducting properties. When transition metal ions are doped into the CdS, it exhibits magnetic properties in addition to semiconducting properties and they are termed as dilute magnetic semiconductors (DMSs. In this paper, we discuss the preparation of sodium bis(2-ethylhexyl sulfonsuccinate (AOT capped CdS nanoparticles and thin films doped with magnetic impurity Mn. Sodium bis(2-ethulexyl sulfonsuccinate (AOT, capping agent promotes the uniform formation of nanoparticles. Optical characterizations are made using the UV-Vis spectrometer, PL, and FTIR. XRD shows the hexagonal structure of the CdS. SEM images and EDS measurements were made for the thin films. EPR shows the clear hyperfine lines corresponding to Mn2+ ion in the CdS nanoparticles.

  3. Development of STI/AOT optimization methodology and an application to the AFWPs with adverse effects

    International Nuclear Information System (INIS)

    Adverse effects caused by the surveillance test for the components of nuclear power plant involve plant transients, unnecessary wear, burden on licensee's time, and the radiation exposure to personnel along with the characteristics of each component. The optimization methodology of STI and AOT has been developed and applied to AFWPs of a reference plant. The approach proposed in this paper consists of the results in minimal mean unavailability of the two-out-of-four system with adverse effects are analytically calculated for the example system. The surveillance testing strategy are given by the sequential test, the staggered test and the train staggered test, which is a mixed test scheme. In the system level, the sensitivity analyses for the STI and AOT, are performed for the measure of the system unavailability of the top event in the fault tree developed for the example system. This methodology may contribute to establishing the basis for the risk-based regulations. (author)

  4. Contaminants of emerging concern in reverse osmosis brine concentrate from indirect/direct water reuse applications.

    Science.gov (United States)

    Romeyn, Travis R; Harijanto, Wesley; Sandoval, Sofia; Delagah, Saied; Sharbatmaleki, Mohamadali

    2016-01-01

    Water shortage is becoming more common due to droughts and global population increases resulting in the increasing popularity of water reuse to create new water sources. Reverse osmosis (RO) membrane systems are popular in these applications since they can produce drinking water quality effluent. Unfortunately, RO systems have the drawback of generating concentrate streams that contain contaminants rejected by the membrane including chemicals of emerging concern (CECs). CECs are chemicals such as hormones, steroids, pesticides, pharmaceuticals, and personal care products that are used for their intended purpose and then released into wastewater. CECs are believed to be detrimental to aquatic wildlife health and pose an unknown human health risk. This research gathered the existing knowledge on CEC presence in concentrate, available proven concentrate treatment methods, their CEC removal abilities, and current CEC regulations. It was found that 127 CECs have been measured in RO concentrate with 100 being detected at least once. The most potent treatment process available is UV/H2O2 as it offers the highest removal rates for the widest range of chemicals. The less expensive process of ozone/biologically activated carbon offers slightly lower removal abilities. This comprehensive report will provide the groundwork for better understanding, regulating and treating concentrate stream CECs.

  5. Autoregressive spatially varying coefficients model for predicting daily PM2.5 using VIIRS satellite AOT

    Science.gov (United States)

    Schliep, E. M.; Gelfand, A. E.; Holland, D. M.

    2015-12-01

    There is considerable demand for accurate air quality information in human health analyses. The sparsity of ground monitoring stations across the United States motivates the need for advanced statistical models to predict air quality metrics, such as PM2.5, at unobserved sites. Remote sensing technologies have the potential to expand our knowledge of PM2.5 spatial patterns beyond what we can predict from current PM2.5 monitoring networks. Data from satellites have an additional advantage in not requiring extensive emission inventories necessary for most atmospheric models that have been used in earlier data fusion models for air pollution. Statistical models combining monitoring station data with satellite-obtained aerosol optical thickness (AOT), also referred to as aerosol optical depth (AOD), have been proposed in the literature with varying levels of success in predicting PM2.5. The benefit of using AOT is that satellites provide complete gridded spatial coverage. However, the challenges involved with using it in fusion models are (1) the correlation between the two data sources varies both in time and in space, (2) the data sources are temporally and spatially misaligned, and (3) there is extensive missingness in the monitoring data and also in the satellite data due to cloud cover. We propose a hierarchical autoregressive spatially varying coefficients model to jointly model the two data sources, which addresses the foregoing challenges. Additionally, we offer formal model comparison for competing models in terms of model fit and out of sample prediction of PM2.5. The models are applied to daily observations of PM2.5 and AOT in the summer months of 2013 across the conterminous United States. Most notably, during this time period, we find small in-sample improvement incorporating AOT into our autoregressive model but little out-of-sample predictive improvement.

  6. Spatiotemporal Spectral Variations of AOT in India’s EEZ over Arabian Sea: Validation of OCM-II

    Directory of Open Access Journals (Sweden)

    C. P. Simha

    2012-01-01

    Full Text Available We report the results of sun-photometric measurements of Aerosol Optical Thickness (AOT in India’s Exclusive Economic Zone (EEZ over the Arabian Sea along with synchronous Ocean Color Monitor (OCM-II derived AOT estimates during December 12, 2009–January 10, 2010. Relatively higher values of Angstrom exponent (α around 1.2 near coast and 0.2–0.8 in the India’s EEZ, observed during the cruise period, indicate the presence of smaller particles near the coast due to anthropogenic activities; and larger particles in the India’s EEZ due to advection of pollutants from Indian subcontinent via long-range transport. Results related to α and its derivative reveal four different aerosol types (urban-industrial, desert-dust, clean-marine, and mixed-type with varying fraction during the study period. Surface radiative forcing due to aerosols is found to be 20 W/m2 over India’s EEZ. OCM-derived AOTs showed good corroboration with in situ measurements with a correlation coefficient of about 0.95. A reasonably good correlation was also observed between AOT and wind speed (R = 0.6; AOT and relative humidity (R = 0.58. The concurrent MODIS AOT data also agree well with those observed by the OCEANSAT (OCM-II satellite during the campaign period.

  7. Application of pressure assisted forward osmosis for water purification and reuse of reverse osmosis concentrate from a water reclamation plant

    KAUST Repository

    Jamil, Shazad

    2016-07-26

    The use of forward osmosis (FO) is growing among the researchers for water desalination and wastewater treatment due to use of natural osmotic pressure of draw solute. In this study pressure assisted forward osmosis (PAFO) was used instead of FO to increase the water production rate. In this study a low concentration of draw solution (0.25 M KCl) was applied so that diluted KCl after PAFO operation can directly be used for fertigation. The performance of PAFO was investigated for the treatment of reverse osmosis concentrate (ROC) from a water reclamation plant. The water production in PAFO was increased by 9% and 29% at applied pressure of 2 and 4 bars, respectively, to feed side based on 90 h of experiments. Granular activated carbon (GAC) pretreatment and HCl softening were used to reduce organic fouling and scaling prior to application of PAFO. It reduced total organic carbon (TOC) and total inorganic carbon (TIC) by around 90% and 85%, respectively from untreated ROC. Subsequently, this led to an increase in permeate flux. In addition, GAC pretreatment adsorbed 12 out of 14 organic micropollutants tested from ROC to below detection limit. This application enabled to minimise the ROC volume with a sustainable operation and produced high quality and safe water for discharge or reuse. The draw solution (0.25 M KCl) used in this study was diluted to 0.14 M KCl, which is a suitable concentration (10 kg/m3) for fertigation, due to water transport from feed solution. © 2016 Elsevier B.V.

  8. Reverse water gas shift reaction over Co-precipitated Ni-CeO2 catalysts

    Institute of Scientific and Technical Information of China (English)

    WANG Luhui; ZHANG Shaoxing; LIU Yuan

    2008-01-01

    The Ni-CeO2 catalysts with different Ni contents were prepared by a co-precipitation method and used for Reverse Water Gas Shift (RWGS) reaction. 2wt.%Ni-CeO2 showed excellent catalytic performance in terms of activity, selectivity, and stability for RWGS reaction. Characterizations of the catalyst samples were conducted by XRD and TPR. The results indicated that, in Ni-CeO2 catalysts, there were three kinds of nickel, nickel ions in ceria lattice, highly dispersed NiO and bulk NiO. Oxygen vacancies were formed in CeO2 lattice due to the incorporation of Ni2+ ions into ceria lattice. Oxygen vacancies formed in ceda lattice and highly dispersed Ni were key active components for RWGS, and bulk Ni was key active component for methanation of CO2.

  9. Reversible B/A Transitions in Single DNA Molecule Immersed in A Water Drop

    CERN Document Server

    Mazur, A K

    2003-01-01

    Clarification of the detailed mechanisms involved in the DNA polymorphism is an important challenge for computational molecular biophysics. This paper reports about reversible A/B transitions in DNA observed in silico in a simulated titration experiment by smooth variation of the size of a water drop around a double helical solute. The estimated range of hydration numbers corresponding to the B/A transition roughly agrees with experimental data. The chain length dependence was studied and it appeared that the transition to A-form is hindered when the fragment becomes shorter than one helical turn. Dynamics of the A/B transition at low hydration is cooperative and is driven mainly by medium range electrostatic interactions of counterions sandwiched between phosphate strands in the major groove. The correspondence of these computational observations to common experimental conditions of A/B transitions is discussed.

  10. Corrosion Inhibition of the Galvanic Couple Copper-Carbon Steel in Reverse Osmosis Water

    Directory of Open Access Journals (Sweden)

    Irene Carrillo

    2011-01-01

    Full Text Available The purpose of this paper is to evaluate the electrochemical behaviour of corrosion inhibition of the copper-carbon steel galvanic couple (Cu-CS, exposed to reverse osmosis water (RO used for rinsing of heat exchangers for heavy duty machinery, during manufacture. Molybdate and nitrite salts were utilized to evaluate the inhibition behaviour under galvanic couple conditions. Cu-CS couple was used as working electrodes to measure open circuit potential (OCP, potentiodynamic polarization (PP, and electrochemical impedance spectroscopy (EIS. The surface conditions were characterized by scanning electron microscopy (SEM and electron dispersive X-ray spectroscopy (EDS. The most effective concentration ratio between molybdate and nitrite corrosion inhibitors was determined. The morphological study indicated molybdate deposition on the anodic sites of the galvanic couple. The design of molybdate-based corrosion inhibitor developed in the present work should be applied to control galvanic corrosion of the Cu-CS couple during cleaning in the manufacture of heat exchangers.

  11. Removal of bisphenol A (BPA) from water by various nanofiltration (NF) and reverse osmosis (RO) membranes.

    Science.gov (United States)

    Yüksel, Suna; Kabay, Nalan; Yüksel, Mithat

    2013-12-15

    The removal of an endocrine disrupting compound, bisphenol A (BPA), from model solutions by selected nanofiltration (NF) and reverse osmosis (RO) membranes was studied. The commercially available membranes NF 90, NF 270, XLE BWRO, BW 30 (Dow FilmTech), CE BWRO and AD SWRO (GE Osmonics) were used to compare their performances for BPA removal. The water permeability coefficients, rejection of BPA and permeate flux values were calculated for all membranes used. No significant changes in their BPA removal were observed for all tight polyamide based NF and RO membranes tested except for loose NF 270 membrane. The polyamide based membranes exhibited much better performance than cellulose acetate membrane for BPA removal. Almost a complete rejection (≥ 98%) for BPA was obtained with three polyamide based RO membranes (BW 30, XLE BWRO and AD SWRO). But cellulose acetate based CE BWRO membrane offered a low and variable (10-40%) rejection for BPA. PMID:23731784

  12. Removal of bisphenol A (BPA) from water by various nanofiltration (NF) and reverse osmosis (RO) membranes.

    Science.gov (United States)

    Yüksel, Suna; Kabay, Nalan; Yüksel, Mithat

    2013-12-15

    The removal of an endocrine disrupting compound, bisphenol A (BPA), from model solutions by selected nanofiltration (NF) and reverse osmosis (RO) membranes was studied. The commercially available membranes NF 90, NF 270, XLE BWRO, BW 30 (Dow FilmTech), CE BWRO and AD SWRO (GE Osmonics) were used to compare their performances for BPA removal. The water permeability coefficients, rejection of BPA and permeate flux values were calculated for all membranes used. No significant changes in their BPA removal were observed for all tight polyamide based NF and RO membranes tested except for loose NF 270 membrane. The polyamide based membranes exhibited much better performance than cellulose acetate membrane for BPA removal. Almost a complete rejection (≥ 98%) for BPA was obtained with three polyamide based RO membranes (BW 30, XLE BWRO and AD SWRO). But cellulose acetate based CE BWRO membrane offered a low and variable (10-40%) rejection for BPA.

  13. Subsurface intakes for seawater reverse osmosis facilities: Capacity limitation, water quality improvement, and economics

    KAUST Repository

    Missimer, Thomas M.

    2013-08-01

    The use of subsurface intake systems for seawater reverse osmosis (SWRO) desalination plants significantly improves raw water quality, reduces chemical usage and environmental impacts, decreases the carbon footprint, and reduces cost of treated water to consumers. These intakes include wells (vertical, angle, and radial type) and galleries, which can be located either on the beach or in the seabed. Subsurface intakes act both as intakes and as part of the pretreatment system by providing filtration and active biological treatment of the raw seawater. Recent investigations of the improvement in water quality made by subsurface intakes show lowering of the silt density index by 75 to 90%, removal of nearly all algae, removal of over 90% of bacteria, reduction in the concentrations of TOC and DOC, and virtual elimination of biopolymers and polysaccharides that cause organic biofouling of membranes. Economic analyses show that overall SWRO operating costs can be reduced by 5 to 30% by using subsurface intake systems. Although capital costs can be slightly to significantly higher compared to open-ocean intake system costs, a preliminary life-cycle cost analysis shows significant cost saving over operating periods of 10 to 30. years. © 2013 Elsevier B.V.

  14. Integrated pretreatment with capacitive deionization for reverse osmosis reject recovery from water reclamation plant.

    Science.gov (United States)

    Lee, Lai Yoke; Ng, How Yong; Ong, Say Leong; Tao, Guihe; Kekre, Kiran; Viswanath, Balakrishnan; Lay, Winson; Seah, Harry

    2009-10-01

    Reverse osmosis (RO) reject recovery from the water reclamation process was demonstrated feasible using an integrated pretreatment scheme followed by the Capacitive Deionization (CDI) process. The RO reject had an average total dissolved solids (TDS) of 1276+/-166 mg/L. Water recovery of 85% with water quality comparable with the RO feed was achieved. Pretreatments using biological activated carbon (BAC) and BAC-ultrafiltration (UF) attained total organic carbon (TOC) removal efficiencies of 23.5+/-6.0% and 39.9+/-9.0%, respectively. Organics removal of RO reject was attributed to simultaneous adsorption and biodegradation in the BAC pretreatment, while further biodegradation in the submerged UF membrane tank provided additional organics removal. Membrane and CDI fouling was reduced by pH adjustment of the pretreated RO reject to approximately 6.5, which prolonged the CDI operation time by at least two times. The CDI process was able to achieve more than 88 and 87% TDS and ion removals, respectively, while PO(4)(3-) and TOC removals were at 52-81% and 50-63%, respectively. PMID:19700181

  15. Solid phase extraction and determination of carbamate pesticides in water samples by reverse-phase HPLC

    Energy Technology Data Exchange (ETDEWEB)

    Moreno-Tovar, J.; Santos-Delgado, M.J. [Departamento de Quimica Analitica, Facultad de ciencias Quimicas, Universidad Complutense de Madrid (Spain)

    1995-12-31

    Solid phase extraction. SPE. using C{sub 1}8 bonded silica cartridges for trace amounts determination of carbaryl, propoxur, thiram, propham and methiocarb in water samples was studied and the breakthrough volume of the cartridges was established. The high enrichment factor and large injection volume admissible in the isocratic reverse-phase HPLC system allows pesticides determination with UV detection at 22o nm even at a concentration lower than 0.05 mug/L. Purified tap natural and underground water samples were spiked with carbamate pesticides in the concentration range 0.16-16.0 mug/L. Large volumes of samples (up to 2L) were passed through available C{sub 1}8, cartridges and eluted with acetonitrile. The preconcentrated samples were analyzed by HPLC using a Spherisorb ODS column with a 42.58 acetonitrile-water mobile phase. From replicate samples, recovery for the pesticides ranged from 79.0 to 103.7% except for thiran which is not retained. Tehe relative standard deviation (n=4 at 0.16 to 1.61 mug/L concetration level) range from 1.1 to 6.8%. (Author) 14 refs.

  16. Activity and Conformation of Yeast Alcohol Dehydrogenase (YADH) Entrapped in Reverse Micelles.

    Science.gov (United States)

    Das; Mozumdar; Maitra

    2000-10-15

    Yeast alcohol dehydrogenase (YADH) solubilized in reverse micelles of aerosol OT (i.e., AOT or sodium bis (2-ethyl hexyl) sulfosuccinate) in isooctane has been shown to be catalytically more active than that in aqueous buffer under optimum conditions of pH, temperature, and water content in reverse micelles. Studies of the secondary structure conformational changes of the enzyme in reverse micelles have been made from circular dichroism spectroscopy. It has been seen that the conformation of YADH in reverse micelles is extremely sensitive to pH, temperature, and water content. A comparison has been made between the catalytic activity of the enzyme and the alpha-helix content in the conformation and it has been observed that the enzyme is most active at the maximum alpha-helix content. While the beta-sheet content in the conformation of the entrapped enzyme was found to be dependent on the enzyme-micelle interface interaction, the alpha-helix and random coil conformations are governed by the degree of entrapment and the extent of rigidity provided by the micelle core to the enzyme structure. Copyright 2000 Academic Press.

  17. Data on daily fluoride intake based on drinking water consumption prepared by household desalinators working by reverse osmosis process.

    Science.gov (United States)

    Karbasdehi, Vahid Noroozi; Dobaradaran, Sina; Esmaili, Abdolhamid; Mirahmadi, Roghayeh; Ghasemi, Fatemeh Faraji; Keshtkar, Mozhgan

    2016-09-01

    In this data article, we evaluated the daily fluoride contents in 20 household desalinators working by reverse osmosis (RO) process in Bushehr, Iran. The concentration levels of fluoride in inlet and outlet waters were determined by the standard SPADNS method using a spectrophotometer (M501 Single Beam Scanning UV/VIS, UK). The fluoride content in outlet waters were compared with EPA and WHO guidelines for drinking water. PMID:27508234

  18. Using microbial desalination cells to reduce water salinity prior to reverse osmosis

    KAUST Repository

    Mehanna, Maha

    2010-01-01

    A microbial desalination cell (MDC) is a new method to reduce the salinity of one solution while generating electrical power from organic matter and bacteria in another (anode) solution. Substantial reductions in the salinity can require much larger volumes of the anode solution than the saline water, but any reduction of salinity will benefit the energy efficiency of a downstream reverse osmosis (RO) desalination system. We investigated here the use of an MDC as an RO pre-treatment method using a new type of air-cathode MDC containing three equally sized chambers. A single cycle of operation using a 1 g L -1 acetate solution reduced the conductivity of salt water (5 g L-1 NaCl) by 43 ± 6%, and produced a maximum power density of 480 mW m-2 with a coulombic efficiency of 68 ± 11%. A higher concentration of acetate (2 g L-1) reduced solution conductivity by 60 ± 7%, and a higher salt concentration (20 g L-1 NaCl) reduced solution conductivity by 50 ± 7%. The use of membranes with increased ion exchange capacities further decreased the solution conductivity by 63 ± 2% (20 g L-1 NaCl). These results demonstrate substantial (43-67%) desalination of water is possible using equal volumes of anode solution and salt water. These results show that MDC treatment could be used to substantially reduce salt concentrations and thus energy demands for downstream RO processing, while at the same time producing electrical power. © 2010 The Royal Society of Chemistry.

  19. Small angle X-ray scattering studies to access the influence of bovine serum albumin (BSA) and carbonic anhydrase (Boca) on the size and interaction among Aerosol-O T reversed micelles as a function of the micellar hydration degree

    International Nuclear Information System (INIS)

    Full text: Reversed micelles (RMs) of AOT (sodium bis-2-ethylhexyl sulfosuccinate) has constitute an efficient system to investigate membrane interaction and physical chemical behavior of short biologically active peptides, proteins and enzymes in water controlled environment and apolar medium. Information may be obtained from protein-membrane interaction, including solubilization, binding location, conformational changes, activity size droplet-dependent, and changes in the properties of RM environment, useful in studies in biocatalysis and bioseparation systems [1]. In this work, changes in the structural features and interactive forces among AOT RMs in hexane were monitored in several stages of micellar hydration W (= [buffer]/[0.1M AOT]), and in the presence of BSA (66.5 kDa) and BCA (30 Kda), by SAXS. The interactive forces between the RMs with proteins were analyzed within the framework of repulsion and attractive interaction potentials through the pairing stick hardsphere (PSHS) model [2]. In this way, the spherical core radius to the system of pure AOT RMs at W = 4, 10, 20 and 30 were respectively 15, 22, 33 and 43 A (20% of polydispersity), evaluated from the particle form factor P(q) modeling [1]. The PSHS analysis from SAXS curves of AOT RMs with BSA and BCA at smaller droplets size of 4 and 10, showed, respectively, an interplay between attractive and repulsive interactions between the micelles (attractive component in S(q) was predominant) with the preservation of the discrete RM radius in the presence of protein. On the other hand, for protein confined in the bigger RM droplet size with W=30, the attractive inter micellar forces were of minor importance for BSA and the appearing of a predominant repulsive hard sphere component in SAXS curves accompanied by a decreasing of the micellar radius to 36 A were detected. For BCA, however, at higher W (30), a phase separation was observed probably associated to the formation of unstable large BCA aggregates

  20. Molecular Thermodynamic Modeling of Reverse Micelles and Water-in-Oil Microemulsions.

    Science.gov (United States)

    Lukanov, Boris; Firoozabadi, Abbas

    2016-04-01

    Surfactant aggregation plays an important role in a variety of chemical and biological nanoscale processes. On a larger scale, using small amounts of amphiphiles compared to large volumes of bulk-phase modifiers can improve the efficiency and reduce the environmental impact of many chemical and industrial processes. To model ternary mixtures of polar, nonpolar, and amphiphilic molecules, we develop a molecular thermodynamic theory for polydisperse water-in-oil (W/O) droplet-type microemulsions and reverse micelles based on global minimization of the Gibbs free energy of the system. The incorporation of size polydispersity into the theoretical formulation has a significant effect on the Gibbs free energy landscape and allows us to accurately predict micelle size distributions and micelle size variation with composition. Results are presented for two sample ionic surfactant/water/oil systems and compared with experimental data. By predicting the structural and compositional characteristics of w/o microemulsions, the molecular thermodynamic approach provides an important bridge between the modeling of ternary systems at the molecular and the macroscopic level. PMID:26919199

  1. Evaluation of emerging contaminants in a drinking water treatment plant using electrodialysis reversal technology.

    Science.gov (United States)

    Gabarrón, S; Gernjak, W; Valero, F; Barceló, A; Petrovic, M; Rodríguez-Roda, I

    2016-05-15

    Emerging contaminants (EC) have gained much attention with globally increasing consumption and detection in aquatic ecosystems during the last two decades from ng/L to lower ug/L. The aim of this study was to evaluate the occurrence and removal of pharmaceutically active compounds (PhACs), endocrine disrupting chemicals (EDCs) and related compounds in a Drinking Water Treatment Plant (DWTP) treating raw water from the Mediterranean Llobregat River. The DWTP combined conventional treatment steps with the world's largest electrodialysis reversal (EDR) facility. 49 different PhACs, EDCs and related compounds were found above their limit of quantification in the influent of the DWTP, summing up to a total concentration of ECs between 1600-4200 ng/L. As expected, oxidation using chlorine dioxide and granular activated carbon filters were the most efficient technologies for EC removal. However, despite the low concentration detected in the influent of the EDR process, it was also possible to demonstrate that this process partially removed ionized compounds, thereby constituting an additional barrier against EC pollution in the product. In the product of the EDR system, only 18 out of 49 compounds were quantifiable in at least one of the four experimental campaigns, showing in all cases removals higher than 65% and often beyond 90% for the overall DWTP process. PMID:26894293

  2. Reverse flow injection spectrophotometric determination of thiram and nabam fungicides in natural water samples

    International Nuclear Information System (INIS)

    A reverse flow injection (rFI) spectrophotometric method is reported for determination of thiram and nabam fungicides in natural water samples. The method is based on the reduction of iron(III) in the presence of thiram/nabam in acidic medium at 60 degree C and formation of iron(II)-ferricyanide complex was measured at 790 nm. The limits of detection (3s blank) were 0.01 and 0.05 micro g mL1 for thiram and nabam respectively with a sample throughput of 60 h1. Calibration graphs were linear over the range of 0.02 - 8.0 micro g mL1 (R2 = 0.9999, n = 8) and 0.1 - 30 micro g mL1 (R2 = 0.9982, n = 10) for thiram and nabam with relative standard deviations (RSDs; n = 3) in the range of 0.8 - 1.6% respectively. Experimental parameters and potential interferences were examined. Thiram and nabam were determined in natural water samples using solid-phase extraction (SPE) procedure and recoveries were in the range of 93+-3 - 105+-2% and 87+-4 - 102+-3% respectively. The results obtained were not significantly different compared with a HPLC method. (author)

  3. Reverse osmosis integrity monitoring in water reuse: The challenge to verify virus removal - A review.

    Science.gov (United States)

    Pype, Marie-Laure; Lawrence, Michael G; Keller, Jurg; Gernjak, Wolfgang

    2016-07-01

    A reverse osmosis (RO) process is often included in the treatment train to produce high quality reuse water from treated effluent for potable purposes because of its high removal efficiency for salinity and many inorganic and organic contaminants, and importantly, it also provides an excellent barrier for pathogens. In order to ensure the continued protection of public health from pathogen contamination, monitoring RO process integrity is necessary. Due to their small sizes, viruses are the most difficult class of pathogens to be removed in physical separation processes and therefore often considered the most challenging pathogen to monitor. To-date, there is a gap between the current log credit assigned to this process (determined by integrity testing approved by regulators) and its actual log removal capability as proven in a variety of laboratory and pilot studies. Hence, there is a challenge to establish a methodology that more closely links to the theoretical performance. In this review, after introducing the notion of risk management in water reuse, we provide an overview of existing and potentially new RO integrity monitoring techniques, highlight their strengths and drawbacks, and debate their applicability to full-scale treatment plants, which open to future research opportunities.

  4. Using reverse osmosis to remove natural organic matter from power plant makeup water

    International Nuclear Information System (INIS)

    A field-scale reverse osmosis (RO) system was used to remove salts and natural organic matter (NOM) from a surface water source. The RO membrane exhibited an NOM solution hydraulic permeability of 8.33 x 10-9 m x s-1 x kPa-1, about 6% less than the clean water value, over pressures ranging from 414 to 1 000 kPa (60 to 145 psi). The rejection of salt and NOM were greater than 98% and 99%, respectively. Under controlled laboratory conditions, greater than 99% mass recovery of NOM could be obtained. A small fraction of NOM was not recovered using hydrodynamic cleaning but could be recovered with chemical cleaning (NaOH wash solution). The mass recovered in the NaOH solution increased from 6% with increasing transmembrane pressures from 414 kPa to 1 000 kPa, respectively. This is consistent with fouling that results from an increase in solution flux, and a concomitant decrease in tangential crossflow velocity. (orig.)

  5. Nanofiltration vs. reverse osmosis for the removal of emerging organic contaminants in water reuse

    KAUST Repository

    Yangali-Quintanilla, Victor

    2011-01-01

    Reverse osmosis (RO) in existing water reuse facilities is a water industry standard. However, that approach may be questioned taking into consideration that "tight" NF can be equal or "better" than RO. NF can achieve the same removals of RO membranes when dealing with emerging organic contaminants (pharmaceuticals, pesticides, endocrine disruptors and others). Experiments using 18 emerging contaminants were performed using membranes NF200 and NF90 at bench-scale units, and for a more complete study, results of NF and RO pilot and fullscale experiments where compared to our experimental results. The removal results showed that NF can remove many emerging contaminants. The average removal by tight NF was 82% for neutral contaminants and 97% for ionic contaminants. The average removal by RO was 85% for neutral contaminants and 99% for ionic contaminants. Aquifer recharge and recovery (ARR) followed by NF can effectively remove emerging contaminants with removals over 90% when loose NF membranes are used. © 2011 2011 Desalination Publications. All rights reserved.

  6. Speech and Language Disorders in a Dialysis Encephalopathy Patient and the Effect of Desferrioxamine and Reverse-Osmosis Water Treatment.

    Science.gov (United States)

    Lehtihalmes, Matti; And Others

    Dialysis encephalopathy is a progressive neurological disorder occurring after long-term hemodialysis in some renal failure patients. Accumulation of aluminum in the brain is suspected as its cause, and the use of reverse osmosis of the dialysis water and administration of desferrioxamine to the patient have been successful in reducing the…

  7. Energy consumption in membrane capacitive deionization for different water recoveries and flow rates, and comparison with reverse osmosis

    NARCIS (Netherlands)

    Zhao, R.; Porada, S.; Biesheuvel, P.M.; Wal, van der A.

    2013-01-01

    Membrane capacitive deionization (MCDI) is a non-faradaic, capacitive technique for desalinating brackish water by adsorbing ions in charged porous electrodes. To compete with reverse osmosis, the specific energy consumption of MCDI needs to be reduced to less than 1 kWh per m3 of freshwater produce

  8. Reverse electrodialysis : Performance of a stack with 50 cells on the mixing of sea and river water

    NARCIS (Netherlands)

    Veerman, J.; Saakes, M.; Metz, S. J.; Harmsen, G. J.

    2009-01-01

    The purpose of reverse electrodialysis (RED) is to produce electricity upon the mixing of two solutions. We studied the power density (W/m(2)) and the energy efficiency (the amount of energy produced from specified volumes of river and sea water in relation to the thermodynamic maximum). With a stac

  9. Rejection of Emerging Organic Contaminants by Nanofiltration and Reverse Osmosis Membranes: Effects of Fouling, Modelling and Water Reuse

    OpenAIRE

    Yangali Quintanilla, V.

    2010-01-01

    The book contains a description of the presence of micropollutants (medicines, hormones, pesticides) in surface water and shows that conventional water treatment poorly removes micropollutants. Nanofiltration and reverse osmosis are more appropriate technologies; however removals can vary depending on the properties of compounds and types of membranes. Thus, quantification of removals is studied by means of multivariate data analysis techniques and more understanding of the separation of micr...

  10. Fluorescence resonance energy transfer in AOT/4-chlorophenol/m-xylene organogels

    Energy Technology Data Exchange (ETDEWEB)

    Dandapat, Manika; Mandal, Debabrata, E-mail: dmandal.chemistry@gmail.com

    2015-06-15

    Fluorescence Resonance Energy Transfer (FRET) between donor coumarins (C102 and C153) and acceptor Rhodamine 6G were studied in AOT/4-chlorophenol/m-xylene organogels. The gel comprises a three-dimensional network of fiber bundles trapping the m-xylene solvent. Each fiber is an aggregate of several strands, and each strand consists of a central columnar stack of the phenols, surrounded by AOT headgroups. Our acceptor is ionic so that it was concentrated near the polar center of the strand, while the neutral donors were likely distributed over a wider region. With C153 as donor, clear evidence of FRET (time-constant~100 ps) was found, which indicated that the donor and acceptor may reside in neighboring strands within the same fiber. However, with C102 as donor, FRET probably occurred over an ultrashort, sub-picosecond time-scale suggesting that the donor and acceptor in this case resided in close vicinity. Thus, C102 tends to localize near the polar centre of the strands, compared to the more hydrophobic C153, which prefers to occupy the relatively non-polar peripheral regions of the strands and fibers. - Highlights: • FRET between coumarin donors and Rhodamine 6G acceptor studied in AOT organogels. • With Coumarin 153 donor, a ~100 ps FRET component detected in both donor and acceptor fluorescence. • With Coumarin 102 donor, FRET component too short to be detected with a time-resolution of ~70 ps. • The FRET rates reveal crucial differences in donor–acceptor distances for the two coumarin donors.

  11. REVERSE MICROEMULSION OF IGEPAL Co-720 SYSTEM AS MICROREACTOR FOR CdS SYNTHESIS

    Directory of Open Access Journals (Sweden)

    Fitria Rahmawati

    2016-08-01

    Full Text Available A Research on CdS synthesis in reverse microemulsion of Igepal CO-720 system has been conducted at various weight ratio of water to surfactant. Igepal CO-720 naturally forms oil in water (o/w emulsion type due to its high HLB (Hydrophilic -Lipophilic Balance value. Therefore, in this research the Igepal CO-720 system was inversed into water in oil (w/o system before it was used as microreactor for CdS synthesis. As comparison, a system of AOT (Aerosol OT; sodium bis (2-ethylhexyl sulfosuccinate which is naturally w/o system was also used as microreactor for CdS synthesis. The prepared CdS was analyzed by X-ray diffraction for crystal identification, scanning electron microscope for morphological analysis, UV-Vis for absorption edge determination and photoelectrochemical testing for photoactivity. The results show that the Igepal CO -720 system can be inverted into w/o system and can be used as microreactor for CdS synthesis. The prepared CdS is in nanosize with the average diameter of 2.517 ± 0.014 nm and the average gap energy of 3.805 ± 0.178 eV. The prepared CdS in Igepal CO-720 system has less regular form in comparison with morphology of the prepared CdS in AOT system. As the ω values decreases the particle diameter decreases, the gap energy increases and the % IPCE increases. It indicates that high surfactant concentration allows small size micelles formation and produced smaller CdS particle that has high surface area and therefore provide higher photocatalytic activity which was indicated by high value of its % IPCE.

  12. High-pressure cloud point data for the system glycerol + olive oil + n-butane + AOT

    OpenAIRE

    J. P. Bender; A. Junges; Franceschi, E.; F. C. Corazza; C. Dariva; J. Vladimir Oliveira; M. L. Corazza

    2008-01-01

    This work reports high-pressure cloud point data for the quaternary system glycerol + olive oil + n-butane + AOT surfactant. The static synthetic method, using a variable-volume view cell, was employed for obtaining the experimental data at pressures up to 27 MPa. The effects of glycerol/olive oil concentration and surfactant addition on the pressure transition values were evaluated in the temperature range from 303 K to 343 K. For the system investigated, vapor-liquid (VLE), liquid-liquid (L...

  13. Water in oil microemulsions as reaction media for a Diels-Alder reaction between N-ethylmaleimide and cyclopentadiene

    NARCIS (Netherlands)

    Engberts, JBFN; Fernandez, E; Garcia-Rio, L; Leis, J.R.

    2006-01-01

    The Diels-Alder reaction between N-ethylmaleimide and cyclopentadiene in water/AOT/isooctane microemulsions, where AOT denotes sodium bis(2-ethylhexyl) sulfosuccinate, was studied. The rate of the reaction was found to be higher than that obtained in pure isooctane, irrespective of the particular mi

  14. Continuous capacitive deionization-electrodialysis reversal through electrostatic shielding for desalination and deionization of water

    Energy Technology Data Exchange (ETDEWEB)

    Dermentzis, Konstantinos [Technological Education Institute, T.E.I. of Kavala, School of Technological Applications, Department of Science, Laboratory of Chemical Technology and Electrochemistry, Agios Loucas, 65404 Kavala (Greece); Ouzounis, Konstantinos [Democritus University of Thrace, School of Engineering, Department of Environmental Engineering, Laboratory of Environmental Chemistry, 67100 Xanthi (Greece)

    2008-10-15

    We report a new concept for capacitive deionization with simple and cheap porous bipolar intermediate graphite electrodes which is operated continuously by constant or alternating polarity without any down time for electrode saturation, regeneration and rinsing steps and certainly without any permselective ion exchange membranes. The proposed process utilizes the advantages of the classical electrodeionization technologies combining them all to a unified continuous capacitive deionization-continuous electrodeionization-electrodialysis-electrodialysis reversal process. Separate and unchanged diluate and concentrate compartments are created in two modes, first by periodical charging/discharging the bipolar intermediate electrodes through a pulsating electric field and second by simultaneous charging/discharging them through a constant or pulsating electric field and electrostatic shielding. Because of coion permeation and the convenience of alternating the polarity without any negative impact on the deionization process, the new technique is less affected by the known membrane associated limitation, such as concentration polarization, limiting current density or scaling. The new electrochemical deionization technique is suitable for regeneration of ion exchange resins and production of high purity deionized water, removal of heavy metal ions from industrial effluents and desalination of brackish or seawater. (author)

  15. DRINKING WATER FROM DESALINATION OF SEAWATER: OPTIMIZATION OF REVERSE OSMOSIS SYSTEM OPERATING PARAMETERS

    Directory of Open Access Journals (Sweden)

    MARWAN M. SHAMEL

    2006-12-01

    Full Text Available This paper reports on the use of pilot scale membrane separation system coupled with another pilot scale plate heat exchanger to investigate the possibilities of sweetening seawater from Telok Kalong Beach, Terengganu, Malaysia. Reverse osmosis (RO membrane of a surface area of 0.5 m2 was used during the experimental runs. Experiments were conducted at different transmembrane pressures (TMP ranged from 40 to 55 bars, operation temperature ranged from 35 to 45oC, feed concentration (TDS ranged from 34900 to 52500 ppm and cross flow velocities ranged from 1.4 to 2.1 m/s. The result show that the flux values increased linearly with TMP as well as sodium ion rejection. Permeate flux values increased proportionally with the temperature and the later effect was more significant at high pressures. The temperature changing has also influenced the rejection of sodium ion. The minerals content especially NaCl and total dissolved solid (TDS in the drinking water produced in this research are conforming to the standards of World Health Organization (WHO.

  16. Determination and occurrence of organic micropollutants in reverse osmosis treatment for advanced water reuse.

    Science.gov (United States)

    Gomez, Veronica; Majamaa, Katariina; Pocurull, Eva; Borrull, Francesc

    2012-01-01

    The growing demand on water resources has increased the interest in wastewater reclamation for multiple end-use applications such as indirect and direct potable reuse. In these applications, the removal of organic micropollutants is of a greater concern than in conventional wastewater treatment. This article presents a collection of data of trace organic micropollutants in an urban wastewater treatment plant (WWTP) in North East Spain using reverse osmosis (RO) membrane treatment. The RO rejection values of the organic molecules studied with a wide range of solute size and hydrophobicity were determined. Several chromatographic methods monitoring different endocrine disrupting chemicals (EDCs), pharmaceuticals and personal care products (PPCPs) were used. Results indicated that secondary effluents from this Spanish WWTP contained most of the studied organic compounds indicating incomplete removal of organics in the conventional treatment of the plant. However, the rejection of most micropollutants was high for all three RO membrane types (low energy, high rejection, fouling resistant) tested. It was observed that some selected micropollutants were less efficiently removed (e.g. the small and polar and the more hydrophobic) and the molecular weight and membrane material influenced removal efficiencies. PMID:22678201

  17. Modeling and Analysis of the Reverse Water Gas Shift Process for In-Situ Propellant Production

    Science.gov (United States)

    Whitlow, Jonathan E.

    2000-01-01

    This report focuses on the development of mathematical models and simulation tools developed for the Reverse Water Gas Shift (RWGS) process. This process is a candidate technology for oxygen production on Mars under the In-Situ Propellant Production (ISPP) project. An analysis of the RWGS process was performed using a material balance for the system. The material balance is very complex due to the downstream separations and subsequent recycle inherent with the process. A numerical simulation was developed for the RWGS process to provide a tool for analysis and optimization of experimental hardware, which will be constructed later this year at Kennedy Space Center (KSC). Attempts to solve the material balance for the system, which can be defined by 27 nonlinear equations, initially failed. A convergence scheme was developed which led to successful solution of the material balance, however the simplified equations used for the gas separation membrane were found insufficient. Additional more rigorous models were successfully developed and solved for the membrane separation. Sample results from these models are included in this report, with recommendations for experimental work needed for model validation.

  18. Effects of surface coating process conditions on the water permeation and salt rejection properties of composite polyamide reverse osmosis membranes

    KAUST Repository

    Louie, Jennifer Sarah

    2011-02-01

    The application of polymer surface coatings to improve the fouling resistance of reverse osmosis membranes tends to increase flow resistance across the membrane. This paper presents a systematic analysis on how membrane properties and performance are impacted by the coating process steps, and investigates how such effects could contribute to lower water flux. On one hand, simply pre-soaking dry aromatic polyamide composite membranes in aliphatic alcohols results in a significant increase in water flux, which is attributed to wetting of pores in the selective polyamide layer and to changes in the polymer structure. This flux increase was not readily reversible, based on a 300-h water permeation test. Conversely, drying a wetted membrane led to a decrease in water flux, which we hypothesize is caused by increased interchain hydrogen-bonding in the selective layer. This drop in water flux was not permanent; higher flux was observed if the same wetted/dried membrane was then re-soaked in ethanol prior to the water permeation experiment. An ethanol pre-soaking step also increased water flux of a PEBAX-coated membrane by nearly 70%. In contrast to the reduction in water flux caused by the specific treatment sequence of ethanol-swelling followed by drying, this same sequence actually increased gas transport. The eight- to ten-fold increase in Knudsen diffusion-based gas permeance after this pre-treatment was attributed to an increase in the number or size of membrane defects. © 2010 Elsevier B.V.

  19. Risk assessments for forest trees: The performance of the ozone flux versus the AOT concepts

    Energy Technology Data Exchange (ETDEWEB)

    Karlsson, P.E. [Swedish Environmental Research Institute (IVL), PO Box 5302, S-400 14, Goeteborg (Sweden)]. E-mail: pererik.karlsson@ivl.se; Braun, S. [Institute for Applied Plant Biology, Schoenenbuch (Switzerland); Broadmeadow, M. [Environmental Research Branch, Forest Research Station, Alice Holt Lodge, Wrecclesham, Farnham, Surrey, GU10 4LH (United Kingdom); Elvira, S. [Ecotoxicidad de la Contaminacion Atmosferica, CIEMAT (ed 70), Avda. Complutense 22, 28040 Madrid (Spain); Emberson, L. [Stockholm Environment Institute at York, Box 373, University of York, York, YO10 5DD (United Kingdom); Gimeno, B.S. [Ecotoxicidad de la Contaminacion Atmosferica, CIEMAT (ed 70), Avda. Complutense 22, 28040 Madrid (Spain); Le Thiec, D. [I.N.R.A. Centre de Recherches Forestieres, UMR Ecologie et Ecophysiologie Forestieres Equipe Bioclimatologie, 54280 Champenoux (France); Novak, K. [WSL, Swiss Federal Research Institute, Zuercherstrasse 111, 8903 Birmensdorf (Switzerland); Oksanen, E. [Department of Biology, University of Joensuu, POB 111, 80101 Joensuu (Finland); Schaub, M. [WSL, Swiss Federal Research Institute, Zuercherstrasse 111, 8903 Birmensdorf (Switzerland); Uddling, J. [Department of Plant and Environmental Sciences, Goeteborg University, PO Box 461, SE-405 30 Goeteborg (Sweden); Wilkinson, M. [Environmental Research Branch, Forest Research Station, Alice Holt Lodge, Wrecclesham, Farnham, Surrey, GU10 4LH (United Kingdom)

    2007-04-15

    Published ozone exposure-response relationships from experimental studies with young trees performed at different sites across Europe were re-analysed in order to test the performance of ozone exposure indices based on AOTX (Accumulated exposure Over a Threshold of X nmol mol{sup -1}) and AF{sub st}Y (Accumulated Stomatal Flux above a threshold of Y nmol m{sup -2} s{sup -1}). AF{sub st}1.6 was superior, as compared to AOT40, for explaining biomass reductions, when ozone sensitive species with differing leaf morphology were included in the analysis, while this was not the case for less sensitive species. A re-analysis of data with young black cherry trees, subject to different irrigation regimes, indicated that leaf visible injuries were more strongly related to the estimated stomatal ozone uptake, as compared to the ozone concentration in the air. Experimental data with different clones of silver birch indicated that leaf thickness was also an important factor influencing the development of ozone induced leaf visible injury. - Ozone stomatal flux based indices were superior, as compared to AOT40, for explaining biomass reductions and leaf visible injury.

  20. TR-ESR Investigation on Reaction of Vitamin C with Excited Triplet of 9,10-phenanthrenequinone in Reversed Micelle Solutions%维生素C对菲醌三重激发态的淬灭机理及动力学研究

    Institute of Scientific and Technical Information of China (English)

    许新胜; 史蕾; 刘毅; 季学韩; 崔执凤

    2011-01-01

    Time-resolved electron spin resonance has been used to study quenching reactions between the antioxidant Vitamin C (VC) and the triplet excited states of 9,10-phenanthrenequinone (PAQ) in ethylene glycol-water (EG-H2O) homogeneous and inhomogeneous reversed micelle solutions. Reversed micelle solutions were used to be the models of physiological environment of biological cell and tissue. In PAQ/EG-H2O homogeneous solution, the excited triplet of PAQ (3PAQ*) abstracts hydrogen atom from solvent EG. In PAQ/VC/EG-H2O solution,3PAQ* abstracts hydrogen atom not only from solvent EG but also from VC. The quenching rate constant of 3PAQ* by VC is close to the diffusion-controlled value of 1.41 × 108 L/(mol.s).In hexadecyltrimethylammonium bromide (CTAB)/EG-H2O and aerosol OT (AOT)/EGH2O reversed micelle solutions; 3PAQ* and VC react around the water-oil interface of the reversed micelle. Exit of 3PAQ* from the lipid phase slows down the quenching reaction.For Triton X-100 (TX-100)/EG-H2O reversed micelle solution, PAQ and VC coexist inside the hydrophilic polyethylene glycol core, and the quenching rate constant of 3PAQ* by VC is larger than those in AOT/EG-H2O and CTAB/EG-H2O reversed micetle solutions, even a little larger than that in EG-H2O homogeneous solution. The strong emissive chemically induced dynamic electron polarization of As- resulted from the effective TM spin polarization transfer in hydrogen abstraction of 3PAQ* from VC.

  1. Handling concentrated water with reverse osmosis technology and economize water%反渗透工艺处理浓水节约水资源

    Institute of Scientific and Technical Information of China (English)

    张秀玲; 杨潘溪; 吴华

    2012-01-01

    反渗透工艺作为一种高效、清洁的脱盐技术在各行各业中广泛应用,但是在生产过程中实际产水率70%左右,会有大约占总进水量30%左右的浓水排放掉,这一点在水资源日趋紧缺的今天造成了水资源的极大浪费,而且也严重污染了环境。现简要介绍对反渗透浓水采用反渗透技术和设备来进一步处理,可以使反渗透浓水的回收率达到80%-85%,回收水可以再利用,节约了水资源。%As a kind of high efficient, clean desalting technology, reverse osmosis technology is widely applied in all walks of life. However, actual rate of out flow is about 70% in production process, the rest 30% of the total water inflow concentrated water is drained off which not only causes a tremendous waste of water resources today when water resource is in short, but also it pollutes environment seriously. This paper briefly introduces adopting reverse osmosis technology and equipments to reverse osmosis concentrated water, which can make the rate of reverse osmosis concentrated water reach 80%-85%, recycled water can be reused and saving water resources.

  2. [Selective detection of viable pathogenic bacteria in water using reverse transcription quantitative PCR].

    Science.gov (United States)

    Lin, Yi-Wen; Li, Dan; Wu, Shu-Xu; He, Miao; Yang, Tian

    2012-11-01

    A reverse transcription q quantitative PCR (RT-qPCR) assay method was established, which can quantify the copy numbers of RNA in pathogenic bacteria of E. coli and Enterococcus faecium. The results showed that cDNA was generated with the RT-PCR reagents, target gene was quantified with the qPCR, the copy numbers of RNA were stable at about 1 copies x CFU(-1) for E. coli and 7.98 x 10(2) copies x CFU(-1) for Enterococcus faecium respectively during the stationary grow phase for the both indicator bacteria [E. coli (6-18 h) and Enterococcus faecium (10-38 h)]. The established RT-qPCR method can quantify the numbers of viable bacteria through detecting bacterial RNA targets. Through detecting the heat-treated E. coli and Enterococcus faecium by three methods (culture method, qPCR, RT-qPCR), we found that the qPCR and RT-qPCR can distinguish 1.43 lg copy non-viable E. coli and 2.5 lg copy non-viable Enterococcus faecium. These results indicated that the established methods could effectively distinguish viable bacteria from non-viable bacteria. Finally we used this method to evaluate the real effluents of the secondary sedimentation of wastewater treatment plant (WWTP), the results showed that the correlation coefficients (R2) between RT-qPCR and culture method were 0.930 (E. coli) and 0.948 (Enterococcus faecium), and this established RT-PCR method can rapidly detect viable pathogenic bacteria in genuine waters. PMID:23323443

  3. A comparison of surface water natural organic matter in raw filtered water samples, XAD, and reverse osmosis isolates

    Science.gov (United States)

    Maurice, P.A.; Pullin, M.J.; Cabaniss, S.E.; Zhou, Q.; Namjesnik-Dejanovic, K.; Aiken, G.R.

    2002-01-01

    This research compared raw filtered waters (RFWs), XAD resin isolates (XAD-8 and XAD-4), and reverse osmosis (RO) isolates of several surface water samples from McDonalds Branch, a small freshwater fen in the New Jersey Pine Barrens (USA). RO and XAD-8 are two of the most common techniques used to isolate natural organic matter (NOM) for studies of composition and reactivity; therefore, it is important to understand how the isolates differ from bulk (unisolated) samples and from one another. Although, any comparison between the isolation methods needs to consider that XAD-8 is specifically designed to isolate the humic fraction, whereas RO concentrates a broad range of organic matter and is not specific to humics. The comparison included for all samples: weight average molecular weight (Mw), number average molecular weight (Mn), polydispersity (??), absorbance at 280nm normalized to moles C (??280) (RFW and isolates); and for isolates only: elemental analysis, % carbon distribution by 13C NMR, and aqueous FTIR spectra. As expected, RO isolation gave higher yield of NOM than XAD-8, but also higher ash content, especially Si and S. Mw decreased in the order: RO>XAD-8>RFW>XAD-4. The Mw differences of isolates compared with RFW may be due to selective isolation (fractionation), or possibly in the case of RO to condensation or coagulation during isolation. 13C NMR results were roughly similar for the two methods, but the XAD-8 isolate was slightly higher in 'aromatic' C and the RO isolate was slightly higher in heteroaliphatic and carbonyl C. Infrared spectra indicated a higher carboxyl content for the XAD-8 isolates and a higher ester:carboxyl ratio for the RO isolates. The spectroscopic data thus are consistent with selective isolation of more hydrophobic compounds by XAD-8, and also with potential ester hydrolysis during that process, although further study is needed to determine whether ester hydrolysis does indeed occur. Researchers choosing between XAD and RO

  4. Kinetic analysis of hydrogen production using anaerobic bacteria in reverse micelles

    Energy Technology Data Exchange (ETDEWEB)

    Zhi, Xiaohua; Yang, Haijun; Yuan, Zhuliang; Shen, Jianquan [Beijing National Laboratory for Molecular Sciences (BNLMS), Laboratory of New Materials, Institute of Chemistry, Chinese Academy of Sciences, Zhongguancun North First Street 2, Beijing 100190 (China)

    2010-04-15

    The micellar formation and entrapment of bacteria cell in reverse micelles were investigated by ultraviolet spectrum (UV), fluorescence spectrum, and scanning electron microscope (SEM). The hydrogen production in reverse micelles was confirmed. The Gompertz equation was employed to evaluate the hydrogen-producing behavior in reverse micellar systems. Different systems including dioctyl sulfosuccinate sodium salt (AOT)-isooctane, sodium dodecyl sulfate (SDS)-benzene and SDS-carbon tetrachloride (CCl{sub 4}) reverse micelles were analysized. The results revealed that the maximum rate of hydrogen production (R{sub m}) was also suitable to formulate the relationship between hydrogen-producing rate and hydrogen productivity in reverse micelles. (author)

  5. Hydrogen production from inexhaustible supplies of fresh and salt water using microbial reverse-electrodialysis electrolysis cells

    KAUST Repository

    Kim, Y.

    2011-09-19

    There is a tremendous source of entropic energy available from the salinity difference between river water and seawater, but this energy has yet to be efficiently captured and stored. Here we demonstrate that H(2) can be produced in a single process by capturing the salinity driven energy along with organic matter degradation using exoelectrogenic bacteria. Only five pairs of seawater and river water cells were sandwiched between an anode, containing exoelectrogenic bacteria, and a cathode, forming a microbial reverse-electrodialysis electrolysis cell. Exoelectrogens added an electrical potential from acetate oxidation and reduced the anode overpotential, while the reverse electrodialysis stack contributed 0.5-0.6 V at a salinity ratio (seawater:river water) of 50. The H(2) production rate increased from 0.8 to 1.6 m(3)-H(2)/m(3)-anolyte/day for seawater and river water flow rates ranging from 0.1 to 0.8 mL/ min. H(2) recovery, the ratio of electrons used for H(2) evolution to electrons released by substrate oxidation, ranged from 72% to 86%. Energy efficiencies, calculated from changes in salinities and the loss of organic matter, were 58% to 64%. By using a relatively small reverse electrodialysis stack (11 membranes), only ~1% of the produced energy was needed for pumping water. Although Pt was used on the cathode in these tests, additional tests with a nonprecious metal catalyst (MoS(2)) demonstrated H(2) production at a rate of 0.8 m(3)/m(3)/d and an energy efficiency of 51%. These results show that pure H(2) gas can efficiently be produced from virtually limitless supplies of seawater and river water, and biodegradable organic matter.

  6. Electrical, optical, and material characterizations of blue InGaN light emitting diodes submitted to reverse-bias stress in water vapor condition

    International Nuclear Information System (INIS)

    In this paper, we investigate degradation of InGaN/GaN light emitting diodes (LEDs) under reverse-bias operations in water vapor and dry air. To examine failure origins, electrical characterizations including current-voltage, breakdown current profiles, optical measurement, and multiple material analyses were performed. Our findings indicate that the diffusion of indium atoms in water vapor can expedite degradation. Investigation of reverse-bias stress can help provide insight into the effects of water vapor on LEDs

  7. Use of reverse micelles in membrane protein structural biology

    Energy Technology Data Exchange (ETDEWEB)

    Van Horn, Wade D. [Vanderbilt University School of Medicine, Department of Biochemistry and Center for Structural Biology (United States); Ogilvie, Mark E.; Flynn, Peter F. [University of Utah, Department of Chemistry (United States)], E-mail: peter.flynn@utah.edu

    2008-03-15

    Membrane protein structural biology is a rapidly developing field with fundamental importance for elucidating key biological and biophysical processes including signal transduction, intercellular communication, and cellular transport. In addition to the intrinsic interest in this area of research, structural studies of membrane proteins have direct significance on the development of therapeutics that impact human health in diverse and important ways. In this article we demonstrate the potential of investigating the structure of membrane proteins using the reverse micelle forming surfactant dioctyl sulfosuccinate (AOT) in application to the prototypical model ion channel gramicidin A. Reverse micelles are surfactant based nanoparticles which have been employed to investigate fundamental physical properties of biomolecules. The results of this solution NMR based study indicate that the AOT reverse micelle system is capable of refolding and stabilizing relatively high concentrations of the native conformation of gramicidin A. Importantly, pulsed-field-gradient NMR diffusion and NOESY experiments reveal stable gramicidin A homodimer interactions that bridge reverse micelle particles. The spectroscopic benefit of reverse micelle-membrane protein solubilization is also explored, and significant enhancement over commonly used micelle based mimetic systems is demonstrated. These results establish the effectiveness of reverse micelle based studies of membrane proteins, and illustrate that membrane proteins solubilized by reverse micelles are compatible with high resolution solution NMR techniques.

  8. High-pressure cloud point data for the system glycerol + olive oil + n-butane + AOT

    Directory of Open Access Journals (Sweden)

    J. P. Bender

    2008-09-01

    Full Text Available This work reports high-pressure cloud point data for the quaternary system glycerol + olive oil + n-butane + AOT surfactant. The static synthetic method, using a variable-volume view cell, was employed for obtaining the experimental data at pressures up to 27 MPa. The effects of glycerol/olive oil concentration and surfactant addition on the pressure transition values were evaluated in the temperature range from 303 K to 343 K. For the system investigated, vapor-liquid (VLE, liquid-liquid (LLE and vapor-liquid-liquid (VLLE equilibrium were recorded. It was experimentally observed that, at a given temperature and surfactant content, an increase in the concentration of glycerol/oil ratio led to a pronounced increase in the slope of the liquid-liquid coexistence curve. A comparison with results reported for the same system but using propane as solvent showed that much lower pressure transition values are obtained when using n-butane.

  9. Unmanned Water Craft Identification and Adaptive Control in Low-Speed and Reversing Regions

    DEFF Research Database (Denmark)

    Theisen, Lukas Roy Svane; Galeazzi, Roberto; Blanke, Mogens

    2013-01-01

    This paper treats L1 adaptive hovering control of an unmanned surface vehicle in a station-keeping mode where a region of zero control authority and under-actuation are main challenges. Low-speed and reversing dynamics are identied from full scale sea trials, and parameter uncertainty is estimate...

  10. Reverse micelle synthesis of oxide nanopowders: mechanisms of precipitate formation and agglomeration effects.

    Science.gov (United States)

    Graeve, Olivia A; Fathi, Hoorshad; Kelly, James P; Saterlie, Michael S; Sinha, Kaustav; Rojas-George, Gabriel; Kanakala, Raghunath; Brown, David R; Lopez, Enrique A

    2013-10-01

    We present an analysis of reverse micelle stability in four model systems. The first two systems, composed of unstable microemulsions of isooctane, water, and Na-AOT with additions of either iron sulfate or yttrium nitrate, were used for the synthesis of iron oxide or yttrium oxide powders. These oxide powders were of nanocrystalline character, but with some level of agglomeration that was dependent on calcination temperature and cleaning procedures. Results show that even though the reverse micellar solutions were unstable, nanocrystalline powders with very low levels of agglomeration could be obtained. This effect can be attributed to the protective action of the surfactant on the surfaces of the powders that prevents neck formation until after all the surfactant has volatilized. A striking feature of the IR spectra collected on the iron oxide powders is the absence of peaks in the ~1715 cm(-1) to 1750 cm(-1) region, where absorption due to the symmetric C=O (carbonyl) stretching occurs. The lack of such peaks strongly suggests the carbonyl group is no longer free, but is actively participating in the surfactant-precipitate interaction. The final two microemulsion systems, containing CTAB as the surfactant, showed that loss of control of the reverse micelle synthesis process can easily occur when the amount of salt in the water domains exceeds a critical concentration. Both model systems eventually resulted in agglomerated powders of broad size distributions or particles that were large compared to the sizes of the reverse micelles, consistent with the notion that the microemulsions were not stable and the powders were precipitated in an uncontrolled fashion. This has implications for the synthesis of nanopowders by reverse micelle synthesis and provides a benchmark for process control if powders of the highest quality are desired. PMID:23906861

  11. Reverse micelles extraction of nattokinase: From model system to real system

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Nattokinase is a novel fibrinolytic enzyme, which is homologous to Subtilisin Carlsberg. In this paper, Subtilisin Carlsberg was taken as a model protein of nattokinase. Effects of pH, ionic strength, concentration of isopropanol on the extraction of Subtilisin Carlsberg with AOT/isooctane reverse micelles system were investigated. Further, the process of reverse micelles extraction of nattokinase from fermentation broth was studied. By taking the reverse micelles of AOT/isooctane as extractant to perform a full extraction cycle, it was found that about eighty percent of the total activity of nattokinase in the fermentation broth could be recovered and the purification factor was about 2.5. Homologous protein could be reasonably used as model protein of a target protein.

  12. Use of reverse micellar systems for the extraction and purification of bromelain from pineapple wastes.

    Science.gov (United States)

    Umesh Hebbar, H; Sumana, B; Raghavarao, K S M S

    2008-07-01

    Reverse micellar systems of CTAB/isooctane/hexanol/butanol and AOT/isooctane are used for the extraction and primary purification of bromelain from crude aqueous extract of pineapple wastes (core, peel, crown and extended stem). The effect of forward as well as back extraction process parameters on the extraction efficiency, activity recovery and purification fold is studied in detail for the pineapple core extract. The optimized conditions for the extraction from core resulted in forward and back extraction efficiencies of 45% and 62%, respectively, using reverse micellar system of cationic surfactant CTAB. A fairly good activity recovery (106%) and purification (5.2-fold) of bromelain is obtained under these conditions. Reverse micellar extraction from peel, extended stem and crown using CTAB system resulted in purification folds of 2.1, 3.5, and 1.7, respectively. Extraction from extended stem using anionic surfactant AOT in isooctane did not yield good results under the operating conditions employed. PMID:17964777

  13. Formation of reverse micelles in supercritical carbon dioxide and its thermodynamics

    Institute of Scientific and Technical Information of China (English)

    WEN Zhen; DANG Zhi; ZONG Minhua; ZHU Zhixin

    2007-01-01

    The solubilization behavior of methyl orange as a solvation probe in multiple systems composed of supercritical carbon dioxide,surfactants and co-solvents,is studied.It is coneluded that some surfactants,such as sodium bis-(2-ethylhexyl)sulfosuccinate(AOT)and isooctyl phenol polyethoxylate (TX-10),could form reverse micelles in supercritical carbon dioxide under the action of butanol.The formation of reverse micelles is a spontaneous process thermodynamically.Specifically for the nonionic surfactant TX-10,the formation of reverse micelles is dependent on the entropy increase in the system,while for the anionic surfactant AOT,the micellization is mainly dominated by the increase in enthalpy at higher temperatures,but by the increase in entropy at lower temperatures.

  14. Layerwise decomposition of water dynamics in reverse micelles: A simulation study of two-dimensional infrared spectrum

    Science.gov (United States)

    Biswas, Rajib; Furtado, Jonathan; Bagchi, Biman

    2013-10-01

    We present computer simulation study of two-dimensional infrared spectroscopy (2D-IR) of water confined in reverse micelles (RMs) of various sizes. The present study is motivated by the need to understand the altered dynamics of confined water by performing layerwise decomposition of water, with an aim to quantify the relative contributions of different layers water molecules to the calculated 2D-IR spectrum. The 0-1 transition spectra clearly show substantial elongation, due to inhomogeneous broadening and incomplete spectral diffusion, along the diagonal in the surface water layer of different sized RMs. Fitting of the frequency fluctuation correlation functions reveal that the motion of the surface water molecules is sub-diffusive and indicate the constrained nature of their dynamics. This is further supported by two peak nature of the angular analogue of van Hove correlation function. With increasing system size, the water molecules become more diffusive in nature and spectral diffusion almost completes in the central layer of the larger size RMs. Comparisons between experiments and simulations establish the correspondence between the spectral decomposition available in experiments with the spatial decomposition available in simulations. Simulations also allow a quantitative exploration of the relative role of water, sodium ions, and sulfonate head groups in vibrational dephasing. Interestingly, the negative cross correlation between force on oxygen and hydrogen of O-H bond in bulk water significantly decreases in the surface layer of each RM. This negative cross correlation gradually increases in the central water pool with increasing RMs size and this is found to be partly responsible for the faster relaxation rate of water in the central pool.

  15. The Development of a Renewable-Energy-Driven Reverse Osmosis System for Water Desalination and Aquaculture Production

    Institute of Scientific and Technical Information of China (English)

    Clark C K Liu

    2013-01-01

    Water and energy are closely linked natural resources-the transportation, treatment, and distribution of water depends on low-cost energy;while power generation requires large volumes of water. Seawater desalination is a mature technology for increasing freshwater supply, but it is essentially a trade of energy for freshwater and is not a viable solution for regions where both water and energy are in short supply. This paper discusses the development and application of a renewable-energy-driven reverse osmosis (RO) system for water desalination and the treatment and reuse of aquaculture wastewater. The system consists of (1) a wind-driven pumping subsystem, (2) a pressure-driven RO membrane desalination subsystem, and (3) a solar-driven feedback control module. The results of the pilot experiments indicated that the system, operated under wind speeds of 3 m s-1 or higher, can be used for brackish water desalination by reducing the salinity of feedwater with total dissolved solids (TDS) of over 3 000 mg L-1 to product water or permeate with a TDS of 200 mg L-1 or less. Results of the pilot experiments also indicated that the system can remove up to 97%of the nitrogenous wastes from the fish pond effluent and can recover and reuse up to 56%of the freshwater supply for fish pond operation.

  16. Reversal of acidification in upland waters of the English Lake District

    Energy Technology Data Exchange (ETDEWEB)

    Tipping, E.; Carrick, T.R.; Hurley, M.A.; James, J.B.; Lawlor, A.J.; Lofts, S.; Rigg, E.; Sutcliffe, D.W.; Woof, C. [Institute of Freshwater Ecology, Ambleside (United Kingdom)

    1998-12-31

    Water chemistry data are reported for five high-altitude standing waters in the English Lake District, with current average pH values in the range 5-7. The waters show long-term increases in pH, ranging from 0.3 to 0.8 pH units, between 1974 and 1997. For the two intensively monitored sites (Devoke Water and Levers Waters), significant decreases in the concentration of non-marine sulphate are demonstrated; these have taken place concurrently with decreases in the atmospheric deposition of pollutant sulphur.

  17. Use of CuNi/YSZ and CuNi/SDC Catalysts for the Reverse Water Gas Shift Reaction

    OpenAIRE

    Maxime Lortie; Isaifan, Rima J.

    2015-01-01

    Cu50Ni50 nanoparticles were synthesized using a modified polyol method and deposited on samarium-doped ceria, SDC, and yttria-stabilized zirconia, YSZ, supports to form reverse water-gas shift, RWGS, catalysts. The best CO yields, obtained with the Cu50Ni50/SDC catalyst, were about 90% of the equilibrium CO yields. In contrast CO yields using Pt/SDC catalysts were equal to equilibrium CO yields at 700°C. Catalyst selectivity to CO was 100% at hydrogen partial pressures equal to CO2 partial...

  18. Characterisation of proton conducting oxide materials for use in reverse water gas shift catalysis and solid oxide fuel cells

    OpenAIRE

    De A. L. Viana, Hermenegildo

    2007-01-01

    This study concerned the preparation, characterisation and evaluation of different proton conductors for the Reverse Water Gas Shift Reaction (RWGS) and their evaluation as electrolytes for Solid Oxide Fuel Cells (SOFC) under H₂ and O₂. Materials with both catalytic and conductive properties are of a great interest, as their use in electrocatalytical systems may be very important. Sr₃CaZr₀.₅Ta₁.₅O₈.₇₅ (SCZT), BaCe₀.₉Y₀.₁O₂.₉₅ (BCY10) and Ba₃Ca₁.₁₈Nb₁.₈₂O₈.₇₃ (BCN18), were the initial material...

  19. Improved hydrogen production by coupled systems of hydrogenase negative photosynthetic bacteria and fermentative bacteria in reverse micelles

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Anita [Centre for Biotechnology, University of Allahabad, Allahabad 211002 (India); Misra, Krishna [Indo-Russian Center for Bioinformatics, Indian Institute of Information Technology, Allahabad 211011 (India)

    2008-11-15

    Significant improvement in biological hydrogen production is achieved by the use of coupled bacterial cells in reverse micellar systems. Two coupled systems (a) Rhodopseudomonas palustris CGA009/Citrobacter Y19, and (b) Rhodobacter sphaeroides 2.4.1/Citrobacter Y19 bacteria have been immobilized separately in aqueous pool of the reverse micelles fabricated by various surfactants (AOT, CBAC and SDS) and apolar organic solvents (benzene and isooctane). The gene for uptake hydrogenase enzyme has been manipulated further for hydrogen generation. Mutants deficient in uptake hydrogenase (Hup{sup -}) were obtained from R. palustris CGA009 and R. sphaeroides 2.4.1, and entrapped with Citrobacter Y19 in the reverse micellar systems. More than two fold increase in hydrogen production was obtained by the use of Hup{sup -} mutants instead of wild-type photosynthetic bacteria together with Citrobacter Y19. Addition of sodium dithionite, a reducing agent to AOT/H{sub 2}O/isooctane reverse micellar system with the coupled systems of wild-type photosynthetic bacteria and fermentative bacterium Y19 effected similar increase in hydrogen production rate as it is obtained by the use of mutants. CBAC/H{sub 2}O/isooctane reverse micellar system is used for the first time for hydrogen production and is as promising as AOT/H{sub 2}O/isooctane reverse micellar system. All reverse micellar systems of coupled bacterial cultures gave encouraging hydrogen production (rate as well as yield) compared to uncoupled bacterial culture. (author)

  20. Nanostructured Titanium Oxide Film- And Membrane-Based Photocatalysis For Water Treatment

    Science.gov (United States)

    Titanium Oxide (TiO2) photocatalysis, one of the ultraviolet (UV)-based advanced oxidation technologies (AOTs) and nanotechnologies (AONs), has attracted great attention for the development of efficient water treatment and purification systems due to the effectiveness ...

  1. Nernst-Planck transport theory for (reverse) electrodialysis: II. Effect of water transport through ion-exchange membranes

    CERN Document Server

    Tedesco, M; Biesheuvel, P M

    2016-01-01

    Transport of water through ion-exchange membranes is of importance both for electrodialysis (ED) and reverse electrodialysis (RED). In this work, we extend our previous theory [J. Membrane Sci., 510, (2016) 370-381] and include water transport in a two-dimensional model for (R)ED. Following a Maxwell-Stefan (MS) approach, ions in the membrane have friction with the water, pore walls, and one another. We show that when ion-ion friction is neglected, the MS-approach is equivalent to the hydrodynamic theory proposed by Deen for nanofiltration. The model describes all fluxes of ions and water self-consistently as function of the driving forces. After validation against experimental data from literature for ED and RED, the model is also used to analyze single-pass seawater ED and RED with highly concentrated solutions. All fluxes and velocities of water and ions in the membranes are calculated, and the influence of water and coion leakage is investigated under different conditions.

  2. Highly and Stably Water Permeable Thin Film Nanocomposite Membranes Doped with MIL-101 (Cr Nanoparticles for Reverse Osmosis Application

    Directory of Open Access Journals (Sweden)

    Yuan Xu

    2016-10-01

    Full Text Available A hydrophilic, hydrostable porous metal organic framework (MOF material-MIL-101 (Cr was successfully doped into the dense selective polyamide (PA layer on the polysulfone (PS ultrafiltration (UF support to prepare a new thin film nanocomposite (TFN membrane for water desalination. The TFN-MIL-101 (Cr membranes were characterized by SEM, AFM, XPS, wettability measurement and reverse osmosis (RO test. The porous structures of MIL-101 (Cr can establish direct water channels in the dense selective PA layer for water molecules to transport through quickly, leading to the increasing water permeance of membranes. With good compatibility between MIL-101 (Cr nanoparticles and the PA layer, the lab made TFN-MIL-101 (Cr membranes integrated tightly and showed a high NaCl salt rejection. MIL-101 (Cr nanoparticles increased water permeance to 2.2 L/m2·h·bar at 0.05 w/v % concentration, 44% higher than the undoped PA membranes; meanwhile, the NaCl rejection remained higher than 99%. This study experimentally verified the potential use of MIL-101 (Cr in advanced TFN RO membranes, which can be used in the diversified water purification field.

  3. Efficiently Combining Water Reuse and Desalination through Forward Osmosis—Reverse Osmosis (FO-RO Hybrids: A Critical Review

    Directory of Open Access Journals (Sweden)

    Gaetan Blandin

    2016-07-01

    Full Text Available Forward osmosis (FO is a promising membrane technology to combine seawater desalination and water reuse. More specifically, in a FO-reverse osmosis (RO hybrid process, high quality water recovered from the wastewater stream is used to dilute seawater before RO treatment. As such, lower desalination energy needs and/or water augmentation can be obtained while delivering safe water for direct potable reuse thanks to the double dense membrane barrier protection. Typically, FO-RO hybrid can be a credible alternative to new desalination facilities or to implementation of stand-alone water reuse schemes. However, apart from the societal (public perception of water reuse for potable application and water management challenges (proximity of wastewater and desalination plants, FO-RO hybrid has to overcome technical limitation such as low FO permeation flux to become economically attractive. Recent developments (i.e., improved FO membranes, use of pressure assisted osmosis, PAO demonstrated significant improvement in water flux. However, flux improvement is associated with drawbacks, such as increased fouling behaviour, lower rejection of trace organic compounds (TrOCs in PAO operation, and limitation in FO membrane mechanical resistance, which need to be better considered. To support successful implementation of FO-RO hybrid in the industry, further work is required regarding up-scaling to apprehend full-scale challenges in term of mass transfer limitation, pressure drop, fouling and cleaning strategies on a module scale. In addition, refined economics assessment is expected to integrate fouling and other maintenance costs/savings of the FO/PAO-RO hybrid systems, as well as cost savings from any treatment step avoided in the water recycling.

  4. Efficiently Combining Water Reuse and Desalination through Forward Osmosis—Reverse Osmosis (FO-RO) Hybrids: A Critical Review

    Science.gov (United States)

    Blandin, Gaetan; Verliefde, Arne R.D.; Comas, Joaquim; Rodriguez-Roda, Ignasi; Le-Clech, Pierre

    2016-01-01

    Forward osmosis (FO) is a promising membrane technology to combine seawater desalination and water reuse. More specifically, in a FO-reverse osmosis (RO) hybrid process, high quality water recovered from the wastewater stream is used to dilute seawater before RO treatment. As such, lower desalination energy needs and/or water augmentation can be obtained while delivering safe water for direct potable reuse thanks to the double dense membrane barrier protection. Typically, FO-RO hybrid can be a credible alternative to new desalination facilities or to implementation of stand-alone water reuse schemes. However, apart from the societal (public perception of water reuse for potable application) and water management challenges (proximity of wastewater and desalination plants), FO-RO hybrid has to overcome technical limitation such as low FO permeation flux to become economically attractive. Recent developments (i.e., improved FO membranes, use of pressure assisted osmosis, PAO) demonstrated significant improvement in water flux. However, flux improvement is associated with drawbacks, such as increased fouling behaviour, lower rejection of trace organic compounds (TrOCs) in PAO operation, and limitation in FO membrane mechanical resistance, which need to be better considered. To support successful implementation of FO-RO hybrid in the industry, further work is required regarding up-scaling to apprehend full-scale challenges in term of mass transfer limitation, pressure drop, fouling and cleaning strategies on a module scale. In addition, refined economics assessment is expected to integrate fouling and other maintenance costs/savings of the FO/PAO-RO hybrid systems, as well as cost savings from any treatment step avoided in the water recycling. PMID:27376337

  5. Efficiently Combining Water Reuse and Desalination through Forward Osmosis-Reverse Osmosis (FO-RO) Hybrids: A Critical Review.

    Science.gov (United States)

    Blandin, Gaetan; Verliefde, Arne R D; Comas, Joaquim; Rodriguez-Roda, Ignasi; Le-Clech, Pierre

    2016-07-01

    Forward osmosis (FO) is a promising membrane technology to combine seawater desalination and water reuse. More specifically, in a FO-reverse osmosis (RO) hybrid process, high quality water recovered from the wastewater stream is used to dilute seawater before RO treatment. As such, lower desalination energy needs and/or water augmentation can be obtained while delivering safe water for direct potable reuse thanks to the double dense membrane barrier protection. Typically, FO-RO hybrid can be a credible alternative to new desalination facilities or to implementation of stand-alone water reuse schemes. However, apart from the societal (public perception of water reuse for potable application) and water management challenges (proximity of wastewater and desalination plants), FO-RO hybrid has to overcome technical limitation such as low FO permeation flux to become economically attractive. Recent developments (i.e., improved FO membranes, use of pressure assisted osmosis, PAO) demonstrated significant improvement in water flux. However, flux improvement is associated with drawbacks, such as increased fouling behaviour, lower rejection of trace organic compounds (TrOCs) in PAO operation, and limitation in FO membrane mechanical resistance, which need to be better considered. To support successful implementation of FO-RO hybrid in the industry, further work is required regarding up-scaling to apprehend full-scale challenges in term of mass transfer limitation, pressure drop, fouling and cleaning strategies on a module scale. In addition, refined economics assessment is expected to integrate fouling and other maintenance costs/savings of the FO/PAO-RO hybrid systems, as well as cost savings from any treatment step avoided in the water recycling.

  6. Efficiently Combining Water Reuse and Desalination through Forward Osmosis-Reverse Osmosis (FO-RO) Hybrids: A Critical Review.

    Science.gov (United States)

    Blandin, Gaetan; Verliefde, Arne R D; Comas, Joaquim; Rodriguez-Roda, Ignasi; Le-Clech, Pierre

    2016-01-01

    Forward osmosis (FO) is a promising membrane technology to combine seawater desalination and water reuse. More specifically, in a FO-reverse osmosis (RO) hybrid process, high quality water recovered from the wastewater stream is used to dilute seawater before RO treatment. As such, lower desalination energy needs and/or water augmentation can be obtained while delivering safe water for direct potable reuse thanks to the double dense membrane barrier protection. Typically, FO-RO hybrid can be a credible alternative to new desalination facilities or to implementation of stand-alone water reuse schemes. However, apart from the societal (public perception of water reuse for potable application) and water management challenges (proximity of wastewater and desalination plants), FO-RO hybrid has to overcome technical limitation such as low FO permeation flux to become economically attractive. Recent developments (i.e., improved FO membranes, use of pressure assisted osmosis, PAO) demonstrated significant improvement in water flux. However, flux improvement is associated with drawbacks, such as increased fouling behaviour, lower rejection of trace organic compounds (TrOCs) in PAO operation, and limitation in FO membrane mechanical resistance, which need to be better considered. To support successful implementation of FO-RO hybrid in the industry, further work is required regarding up-scaling to apprehend full-scale challenges in term of mass transfer limitation, pressure drop, fouling and cleaning strategies on a module scale. In addition, refined economics assessment is expected to integrate fouling and other maintenance costs/savings of the FO/PAO-RO hybrid systems, as well as cost savings from any treatment step avoided in the water recycling. PMID:27376337

  7. Removal of pharmaceuticals and endocrine disrupting compounds in a water recycling process using reverse osmosis systems

    OpenAIRE

    Al-Rifai, Jawad H.; Khabbaz, Hadi; Schaefer, Andrea I.

    2011-01-01

    A detailed investigation was carried out to evaluate the occurrence, persistence and fate of a range of micropollutants at different processing points at a full-scale water recycling plant (WRP) in Queensland, Australia. The WRP, which combines an advanced water treatment plant (AWTP) with a wastewater treatment plant (WWTP), produces high quality recycled water for industrial users. The concentrations of 11 pharmaceuticals from various therapeutic categories and two endocrine disrupting chem...

  8. Removal of pharmaceuticals and endocrine disrupting compounds in water recycling process using reverse osmosis systems

    OpenAIRE

    Al-Rifai, Jawad H.; Khabbazb, Hadi; Schäfer, Andrea

    2011-01-01

    A detailed investigation was carried out to evaluate the occurrence, persistence and fate of a range of micropollutants at different processing points at a full-scale water recycling plant (WRP) in Queensland, Australia. The WRP, which combines an advanced water treatment plant (AWTP) with a wastewater treatment plant (WWTP), produces high quality recycled water for industrial users. The concentrations of 11 pharmaceuticals from various therapeutic categories and two endocrine dis...

  9. The influence of water flow (reversal) on bond strength development in young masonry

    NARCIS (Netherlands)

    Groot, C.; Larbi, J.

    1999-01-01

    Water loss from the fresh mortar is believed to be related to mortar-brick bond strength development in masonry. Recent research on mortar-brick bond has shown that, particularly, effects of water flow on the composition and the hydration conditions of the mortar-brick interface have to be taken int

  10. Comparing concentration-based (AOT40) and stomatal uptake (PODY) metrics for ozone risk assessment to European forests.

    Science.gov (United States)

    Anav, Alessandro; De Marco, Alessandra; Proietti, Chiara; Alessandri, Andrea; Dell'Aquila, Alessandro; Cionni, Irene; Friedlingstein, Pierre; Khvorostyanov, Dmitry; Menut, Laurent; Paoletti, Elena; Sicard, Pierre; Sitch, Stephen; Vitale, Marcello

    2016-04-01

    Tropospheric ozone (O3) produces harmful effects to forests and crops, leading to a reduction of land carbon assimilation that, consequently, influences the land sink and the crop yield production. To assess the potential negative O3 impacts to vegetation, the European Union uses the Accumulated Ozone over Threshold of 40 ppb (AOT40). This index has been chosen for its simplicity and flexibility in handling different ecosystems as well as for its linear relationships with yield or biomass loss. However, AOT40 does not give any information on the physiological O3 uptake into the leaves since it does not include any environmental constraints to O3 uptake through stomata. Therefore, an index based on stomatal O3 uptake (i.e. PODY), which describes the amount of O3 entering into the leaves, would be more appropriate. Specifically, the PODY metric considers the effects of multiple climatic factors, vegetation characteristics and local and phenological inputs rather than the only atmospheric O3 concentration. For this reason, the use of PODY in the O3 risk assessment for vegetation is becoming recommended. We compare different potential O3 risk assessments based on two methodologies (i.e. AOT40 and stomatal O3 uptake) using a framework of mesoscale models that produces hourly meteorological and O3 data at high spatial resolution (12 km) over Europe for the time period 2000-2005. Results indicate a remarkable spatial and temporal inconsistency between the two indices, suggesting that a new definition of European legislative standard is needed in the near future. Besides, our risk assessment based on AOT40 shows a good consistency compared to both in-situ data and other model-based datasets. Conversely, risk assessment based on stomatal O3 uptake shows different spatial patterns compared to other model-based datasets. This strong inconsistency can be likely related to a different vegetation cover and its associated parameterizations.

  11. Comparing concentration-based (AOT40) and stomatal uptake (PODY) metrics for ozone risk assessment to European forests.

    Science.gov (United States)

    Anav, Alessandro; De Marco, Alessandra; Proietti, Chiara; Alessandri, Andrea; Dell'Aquila, Alessandro; Cionni, Irene; Friedlingstein, Pierre; Khvorostyanov, Dmitry; Menut, Laurent; Paoletti, Elena; Sicard, Pierre; Sitch, Stephen; Vitale, Marcello

    2016-04-01

    Tropospheric ozone (O3) produces harmful effects to forests and crops, leading to a reduction of land carbon assimilation that, consequently, influences the land sink and the crop yield production. To assess the potential negative O3 impacts to vegetation, the European Union uses the Accumulated Ozone over Threshold of 40 ppb (AOT40). This index has been chosen for its simplicity and flexibility in handling different ecosystems as well as for its linear relationships with yield or biomass loss. However, AOT40 does not give any information on the physiological O3 uptake into the leaves since it does not include any environmental constraints to O3 uptake through stomata. Therefore, an index based on stomatal O3 uptake (i.e. PODY), which describes the amount of O3 entering into the leaves, would be more appropriate. Specifically, the PODY metric considers the effects of multiple climatic factors, vegetation characteristics and local and phenological inputs rather than the only atmospheric O3 concentration. For this reason, the use of PODY in the O3 risk assessment for vegetation is becoming recommended. We compare different potential O3 risk assessments based on two methodologies (i.e. AOT40 and stomatal O3 uptake) using a framework of mesoscale models that produces hourly meteorological and O3 data at high spatial resolution (12 km) over Europe for the time period 2000-2005. Results indicate a remarkable spatial and temporal inconsistency between the two indices, suggesting that a new definition of European legislative standard is needed in the near future. Besides, our risk assessment based on AOT40 shows a good consistency compared to both in-situ data and other model-based datasets. Conversely, risk assessment based on stomatal O3 uptake shows different spatial patterns compared to other model-based datasets. This strong inconsistency can be likely related to a different vegetation cover and its associated parameterizations. PMID:26492093

  12. Forward osmosis for the treatment of reverse osmosis concentrate from water reclamation: process performance and fouling control.

    Science.gov (United States)

    Kazner, C; Jamil, S; Phuntsho, S; Shon, H K; Wintgens, T; Vigneswaran, S

    2014-01-01

    While high quality water reuse based on dual membrane filtration (membrane filtration or ultrafiltration, followed by reverse osmosis) is expected to be progressively applied, treatment and sustainable management of the produced reverse osmosis concentrate (ROC) are still important issues. Forward osmosis (FO) is a promising technology for maximising water recovery and further dewatering ROC so that zero liquid discharge is produced. Elevated concentrations of organic and inorganic compounds may act as potential foulants of the concentrate desalting system, in that they consist of, for example, FO and a subsequent crystallizer. The present study investigated conditions under which the FO system can serve as concentration phase with the focus on its fouling propensity using model foulants and real ROC. Bulk organics from ROC consisted mainly of humic acids (HA) and building blocks since wastewater-derived biopolymers were retained by membrane filtration or ultrafiltration. Organic fouling of the FO system by ROC-derived bulk organics was low. HA was only adsorbed moderately at about 7% of the initial concentration, causing a minor flux decline of about 2-4%. However, scaling was a major impediment to this process if not properly controlled, for instance by pH adjustment or softening.

  13. Biofouling of reverse osmosis membranes used in river water purification for drinking purposes: analysis of microbial populations.

    Science.gov (United States)

    Chiellini, Carolina; Iannelli, Renato; Modeo, Letizia; Bianchi, Veronica; Petroni, Giulio

    2012-01-01

    Biofouling in water treatment processes represents one of the most frequent causes of plant performance decline. Investigation of clogged membranes (reverse osmosis membranes, microfiltration membranes and ultrafiltration membranes) is generally performed on fresh membranes. In the present study, a multidisciplinary autopsy of a reverse osmosis membrane (ROM) was conducted. The membrane, which was used in sulfate-rich river water purification for drinking purposes, had become inoperative after 6 months because of biofouling and was later stored for 18 months in dry conditions before analysis. SSU rRNA gene library construction, clone sequencing, T-RFLP, light microscope, and scanning electron microscope (SEM) observations were used to identify the microorganisms present on the membrane and possibly responsible for biofouling at the time of removal. The microorganisms were mainly represented by bacteria belonging to the phylum Actinobacteria and by a single protozoan species belonging to the Lobosea group. The microbiological analysis was interpreted in the context of the treatment plant operations to hypothesize as to the possible mechanisms used by microorganisms to enter the plant and colonize the ROM surface.

  14. Factors affecting fluoride and natural organic matter (NOM) removal from natural waters in Tanzania by nanofiltration/reverse osmosis.

    Science.gov (United States)

    Shen, Junjie; Schäfer, Andrea I

    2015-09-15

    This study examined the feasibility of nanofiltration (NF) and reverse osmosis (RO) in treating challenging natural tropical waters containing high fluoride and natural organic matter (NOM). A total of 166 water samples were collected from 120 sources within northern Tanzania over a period of 16 months. Chemical analysis showed that 81% of the samples have fluoride levels exceeding the WHO drinking guideline of 1.5mg/L. The highest fluoride levels were detected in waters characterized by high ionic strength, high inorganic carbon and on some occasions high total organic carbon (TOC) concentrations. Bench-scale experiments with 22 representative waters (selected based on fluoride concentration, salinity, origin and in some instances organic matter) and 6 NF/RO membranes revealed that ionic strength and recovery affected fluoride retention and permeate flux. This is predominantly due to osmotic pressure and hence the variation of diffusion/convection contributes to fluoride transport. Different membranes had distinct fluoride removal capacities, showing different raw water concentration treatability limits regarding the WHO guideline compliance. BW30, BW30-LE and NF90 membranes had a feed concentration limit of 30-40 mg/L at 50% recovery. NOM retention was independent of water matrices but is governed predominantly by size exclusion. NOM was observed to have a positive impact on fluoride removal. Several mechanisms could contribute but further studies are required before a conclusion could be drawn. In summary, NF/RO membranes were proved to remove both fluoride and NOM reliably even from the most challenging Tanzanian waters, increasing the available drinking water sources.

  15. Factors affecting fluoride and natural organic matter (NOM) removal from natural waters in Tanzania by nanofiltration/reverse osmosis.

    Science.gov (United States)

    Shen, Junjie; Schäfer, Andrea I

    2015-09-15

    This study examined the feasibility of nanofiltration (NF) and reverse osmosis (RO) in treating challenging natural tropical waters containing high fluoride and natural organic matter (NOM). A total of 166 water samples were collected from 120 sources within northern Tanzania over a period of 16 months. Chemical analysis showed that 81% of the samples have fluoride levels exceeding the WHO drinking guideline of 1.5mg/L. The highest fluoride levels were detected in waters characterized by high ionic strength, high inorganic carbon and on some occasions high total organic carbon (TOC) concentrations. Bench-scale experiments with 22 representative waters (selected based on fluoride concentration, salinity, origin and in some instances organic matter) and 6 NF/RO membranes revealed that ionic strength and recovery affected fluoride retention and permeate flux. This is predominantly due to osmotic pressure and hence the variation of diffusion/convection contributes to fluoride transport. Different membranes had distinct fluoride removal capacities, showing different raw water concentration treatability limits regarding the WHO guideline compliance. BW30, BW30-LE and NF90 membranes had a feed concentration limit of 30-40 mg/L at 50% recovery. NOM retention was independent of water matrices but is governed predominantly by size exclusion. NOM was observed to have a positive impact on fluoride removal. Several mechanisms could contribute but further studies are required before a conclusion could be drawn. In summary, NF/RO membranes were proved to remove both fluoride and NOM reliably even from the most challenging Tanzanian waters, increasing the available drinking water sources. PMID:26005995

  16. Ultrafast IR Spectroscopy on Aqueous Reverse-Micellar Nano-Droplets

    NARCIS (Netherlands)

    Cringus, Dan; Milder, Maaike T.W.; Pshenichnikov, Maxim S.; Wiersma, Douwe A.; Lindner, Jörg; Vöhringer, Peter; Kobayashi, Takayoshi; Kobayashi, Tetsuro; Nelson, Keith A.; Okada, Tadashi; Silvestri, Sandro De

    2005-01-01

    The ultrafast dynamics of water nano-droplets (1-10 nm size) of the L2-phase of the ternary mixture H2O-AOT-CCl4 have been studied using frequency-resolved mid-infrared pump-probe spectroscopy in the spectral region of the OH-stretching vibration.

  17. Pilot-Scale Investigation of Forward/Reverse Osmosis Hybrid System for Seawater Desalination Using Impaired Water from Steel Industry

    Directory of Open Access Journals (Sweden)

    Hanaa M. Ali

    2016-01-01

    Full Text Available This paper was focused on the investigation of a forward osmosis- (FO- reverse osmosis (RO hybrid process to cotreat seawater and impaired water from steel industry. By using this hybrid process, seawater can be diluted before desalination, hence reducing the energy cost of desalination, and simultaneously contaminants present in the impaired water are prevented from migrating into the product water through the FO and RO membranes. The main objective of this work was to investigate on pilot-scale system the performance of the combined FO pretreatment and RO desalination hybrid system and specifically its effects on membrane fouling and overall solute rejection. Firstly, optimization of the pilot-scale FO process to obtain the most suitable and stable operating conditions for practical application was investigated. Secondly, pilot-scale RO process performance as a posttreatment to FO process was evaluated in terms of water flux and rejection. The results indicated that the salinity of seawater reduced from 35000 to 13000 mg/L after 3 hrs using FO system, while after 6 hrs it approached 10000 mg/L. Finally, FO/RO system was tested on continuous operation for 15 hrs and it was demonstrated that no pollutant was detected neither in draw solution nor in RO permeate after the end of operating time.

  18. Fuel from Bacteria, CO2, Water, and Solar Energy: Engineering a Bacterial Reverse Fuel Cell

    Energy Technology Data Exchange (ETDEWEB)

    None

    2010-07-01

    Electrofuels Project: Harvard is engineering a self-contained, scalable Electrofuels production system that can directly generate liquid fuels from bacteria, carbon dioxide (CO2), water, and sunlight. Harvard is genetically engineering bacteria called Shewanella, so the bacteria can sit directly on electrical conductors and absorb electrical current. This current, which is powered by solar panels, gives the bacteria the energy they need to process CO2 into liquid fuels. The Harvard team pumps this CO2 into the system, in addition to water and other nutrients needed to grow the bacteria. Harvard is also engineering the bacteria to produce fuel molecules that have properties similar to gasoline or diesel fuel—making them easier to incorporate into the existing fuel infrastructure. These molecules are designed to spontaneously separate from the water-based culture that the bacteria live in and to be used directly as fuel without further chemical processing once they’re pumped out of the tank.

  19. A predictive model of reverse micelles solubilizing water for solvent extraction.

    Science.gov (United States)

    Bley, Michael; Siboulet, Bertrand; Karmakar, Anwesa; Zemb, Thomas; Dufrêche, Jean-François

    2016-10-01

    Herein, a minimal model for the common case of W/O solubilization of badly soluble compounds present in an excess phase by reverse micellar aggregates in chemical equilibrium with its single compounds is introduced. A simple model of such liquid-liquid extractions is crucial for obtaining predictive parameter for the modelling of nuclear waste management and hydrometallurgic recycling strategies. The standard Gibbs free energy of aggregation and the concentration of the corresponding aggregate is calculated within a multiple-equilibria approach for a set of aggregate compositions of solute and amphiphilic extractant molecules. This minimal model provides potential surfaces estimating the stability of different aggregate compositions with 6.2kJmol(-1) as a generalized bending constant. The complete concentrations of free and aggregated extractant species as well as the favored aggregation numbers, the polydispersity, the activity of the organic solvent, and the critical concentrations are captured by this thermodynamic model. An increase of the apparent critical micelle concentration for an increasing solute content in the aqueous phase is detected by this method. PMID:27376975

  20. The influence to reverse osmosis of the chemical characteristics of water%水化学对反渗透的影响

    Institute of Scientific and Technical Information of China (English)

    贺晨; 张晓辉

    2011-01-01

    I t is importment of the chemical characteristics of water for applying and designing of reverse osmosis I t will be failed when you design and operate reverse osmosisifyou unknown thewater chemical%水的化学特性对反渗透的设计和应用非常重要,不了解水化学将会导致反渗透设计和运行的失败。

  1. Lyophilization and Reconstitution of Reverse-Osmosis Concentrated Natural Organic Matter from a Drinking Water Source

    Science.gov (United States)

    Disinfection by-product (DBP) research can be complicated by difficulties in shipping large water quantities and changing natural organic matter (NOM) characteristics over time. To overcome these issues, it is advantageous to have a reliable method for concentrating NOM with min...

  2. Microbial community analysis of fouled reverse osmosis membranes used in water recycling

    KAUST Repository

    Ayache, C.

    2013-06-01

    Biofouling on RO membranes has major cost implications in water reclamation. In this study membranes and water samples were collected from a RO pilot-plant operated on two sites to study the differences in microbial communities in order to develop a better understanding of the biofouling. For the two sites studied, the examination of the front membrane of the first stage and the tail membrane of the second stage of the RO train using 16S rRNA gene-based molecular technique showed that bacteria were similar on both stages and no significant effect of the membrane location within the RO train on the biofilm development could be discerned. However, the comparison of the identified bacteria from membrane samples between the two sites showed that each site is specific, leading to a different composition of microbial communities. The different nutrient concentrations in the RO feed water due to the different biological pre-treatments are one potential explanation for the observed differences in the microbial communities. Seasonal variations also play a major role in the development of microbial communities as shown by the significant differences observed between the communities measured in the samples in winter and summer on the second site. The results did not show similarity between the species identified on the RO membranes and in the feed water. Hence, the relationship of microbial community between the water generated during the pre-treatment process and RO membranes is not obvious. From this study, results showed that there is an actual need to investigate the development of microbial communities on membrane surface in real conditions in order to suggest tailored solutions for biofouling control and removal. © 2013 Elsevier Ltd.

  3. Microbial community analysis of fouled reverse osmosis membranes used in water recycling.

    Science.gov (United States)

    Ayache, C; Manes, C; Pidou, M; Croué, J P; Gernjak, W

    2013-06-15

    Biofouling on RO membranes has major cost implications in water reclamation. In this study membranes and water samples were collected from a RO pilot-plant operated on two sites to study the differences in microbial communities in order to develop a better understanding of the biofouling. For the two sites studied, the examination of the front membrane of the first stage and the tail membrane of the second stage of the RO train using 16S rRNA gene-based molecular technique showed that bacteria were similar on both stages and no significant effect of the membrane location within the RO train on the biofilm development could be discerned. However, the comparison of the identified bacteria from membrane samples between the two sites showed that each site is specific, leading to a different composition of microbial communities. The different nutrient concentrations in the RO feed water due to the different biological pre-treatments are one potential explanation for the observed differences in the microbial communities. Seasonal variations also play a major role in the development of microbial communities as shown by the significant differences observed between the communities measured in the samples in winter and summer on the second site. The results did not show similarity between the species identified on the RO membranes and in the feed water. Hence, the relationship of microbial community between the water generated during the pre-treatment process and RO membranes is not obvious. From this study, results showed that there is an actual need to investigate the development of microbial communities on membrane surface in real conditions in order to suggest tailored solutions for biofouling control and removal.

  4. Assessment of nanofiltration and reverse osmosis potentialities to recover metals, sulfuric acid, and recycled water from acid gold mining effluent.

    Science.gov (United States)

    Ricci, Bárbara C; Ferreira, Carolina D; Marques, Larissa S; Martins, Sofia S; Amaral, Míriam C S

    2016-01-01

    This work assessed the potential of nanofiltration (NF) and reverse osmosis (RO) to treat acid streams contaminated with metals, such as effluent from the pressure oxidation process (POX) used in refractory gold ore processing. NF and RO were evaluated in terms of rejections of sulfuric acid and metals. Regarding NF, high sulfuric acid permeation (∼100%), was observed, while metals were retained with high efficiencies (∼90%), whereas RO led to high acid rejections (gold ore processing or commercialized. A metal-enriched stream could be also recovered in NF retentate and transferred to a subsequent metal recovery stage. In addition, considering the high acid rejection obtained through the proposed system, RO permeate could be used as recycling water. PMID:27438241

  5. An open reversed Brayton cycle with regeneration using moist air for deep freeze cooled by circulating water

    Energy Technology Data Exchange (ETDEWEB)

    Hou, Shaobo [Guangdong Ocean University, College of Engineering, East Jiefang Rd. No. 40, Xiashan, Zhanjiang, Guangdong 524006 (China); Northwestern Polytechnical University, School of Aeroengine and Thermal Power Engineering, Xi' an, Shaanxi 710072 (China); Zhang, Hefei [Northwestern Polytechnical University, School of Aeroengine and Thermal Power Engineering, Xi' an, Shaanxi 710072 (China)

    2009-01-15

    This paper presents an open reversed Brayton cycle with regeneration using moist air for deep freeze cooled by circulating water, and proves its feasibility through performance simulation. Pinch technology is used to analyze the cooling of the wet air after compressor and the water used for cooling wet air after compressor. Its refrigeration depends mainly on the sensible heat of air and the latent heat of water vapor, its performance is more efficient than a conventional air-cycle, and the utilization of turbo-machinery makes it possible. The adoption of this cycle will make deep freeze easily and reduce initial cost because very low temperature, about -55 C, air is obtained. The sensitivity analysis of coefficient of performance to the efficiency of compressor and the efficiency of compressor, and the results of the cycle are also given. The simulation results show that the COP of this system depends on the temperature before turbine, the efficiency of compressor and the efficiency of compressor, and varies with the wet bulb temperature of the outdoor air. Humid air is a perfect working fluid for deep freeze with no cost to the user. (author)

  6. Culturable bacterial diversity from a feed water of a reverse osmosis system, evaluation of biofilm formation and biocontrol using phages.

    Science.gov (United States)

    Belgini, D R B; Dias, R S; Siqueira, V M; Valadares, L A B; Albanese, J M; Souza, R S; Torres, A P R; Sousa, M P; Silva, C C; De Paula, S O; Oliveira, V M

    2014-10-01

    Biofilm formation on reverse osmosis (RO) systems represents a drawback in the application of this technology by different industries, including oil refineries. In RO systems the feed water maybe a source of microbial contamination and thus contributes for the formation of biofilm and consequent biofouling. In this study the planktonic culturable bacterial community was characterized from a feed water of a RO system and their capacities were evaluated to form biofilm in vitro. Bacterial motility and biofilm control were also analysed using phages. As results, diverse Protobacteria, Actinobacteria and Bacteroidetes were identified. Alphaproteobacteria was the predominant group and Brevundimonas, Pseudomonas and Mycobacterium the most abundant genera. Among the 30 isolates, 11 showed at least one type of motility and 11 were classified as good biofilm formers. Additionally, the influence of non-specific bacteriophage in the bacterial biofilms formed in vitro was investigated by action of phages enzymes or phage infection. The vB_AspP-UFV1 (Podoviridae) interfered in biofilm formation of most tested bacteria and may represent a good alternative in biofilm control. These findings provide important information about the bacterial community from the feed water of a RO system that may be used for the development of strategies for biofilm prevention and control in such systems.

  7. Fouling of reverse osmosis membranes by hydrocarbonated and fluorinated surfactants contained in firefighting water

    OpenAIRE

    Baudequin, Clement; Couallier, Estelle; Mai, Zhaohuan; Rakib, Mohammed; Deguerry, Isabelle; Severac, Romain; Pabon, Martial

    2012-01-01

    Large class B fires -- i.e. polar or non polar burning liquids -- can occur in places like refineries, airports or chemical plants. Such fires can be put out with the help of fire fighting foams prepared from specific aqueous formulations, called foam concentrates diluted in water to 1-6% and applied with a nozzle under the form of foam. Foam concentrates usually contain hydrocarbon surfactants or protein hydrolysates (synthetic or proteinic concentrate), and one or several fluorinated surfac...

  8. Stronger sexual selection in warmer waters: the case of a sex role reversed pipefish.

    Directory of Open Access Journals (Sweden)

    Nuno M Monteiro

    Full Text Available In order to answer broader questions about sexual selection, one needs to measure selection on a wide array of phenotypic traits, simultaneously through space and time. Nevertheless, studies that simultaneously address temporal and spatial variation in reproduction are scarce. Here, we aimed to investigate the reproductive dynamics of a cold-water pipefish simultaneously through time (encompassing variation within each breeding cycle and as individuals grow and space (by contrasting populations experiencing distinct water temperature regimes in order to test hypothesized differences in sexual selection. Even though the sampled populations inhabited locations with very different water temperature regimes, they exhibited considerable similarities in reproductive parameters. The most striking was the existence of a well-defined substructure in reproductive activity, where larger individuals reproduce for longer periods, which seemed dependent on a high temperature threshold for breeding rather than on the low temperatures that vary heavily according to latitude. Furthermore, the perceived disparities among populations, such as size at first reproduction, female reproductive investment, or degree of sexual size dimorphism, seemed dependent on the interplay between seawater temperature and the operational sex ratio (OSR. Contrary to our expectations of an enhanced opportunity for sexual selection in the north, we found the opposite: higher female reproductive investment coupled with increased sexual size dimorphism in warmer waters, implying that a prolonged breeding season does not necessarily translate into reduced sexual selection pressure. In fact, if the limited sex has the ability to reproduce either continuously or recurrently during the entire breeding season, an increased opportunity for sexual selection might arise from the need to compete for available partners under strongly biased OSRs across protracted breeding seasons. A more general

  9. 反渗透系统浓水回收利用方案介绍%Introduction of Concentrated Water Recycling Scheme in Reverse Osmosis System

    Institute of Scientific and Technical Information of China (English)

    韩华全

    2012-01-01

    The application of reverse osmosis system in painting industry and several condense water treatment of reverse osmosis system technology which used broadly in home and abroad were briefly introduced. The recycling using situation of the condense water in reverse osmosis system was introduced, the status was analyzed and the recycling using of the condense water was proposed too.%简要介绍反渗透技术在涂装行业的应用及国内外目前使用较多的几种反渗透系统浓水处置方法,说明当前反渗透系统浓水回收利用情况,分析并提出浓水回收利用方案。

  10. Hydrophobic ion pairing of a minocycline/Ca(2+)/AOT complex for preparation of drug-loaded PLGA nanoparticles with improved sustained release.

    Science.gov (United States)

    Holmkvist, Alexander Dontsios; Friberg, Annika; Nilsson, Ulf J; Schouenborg, Jens

    2016-02-29

    Polymeric nanoparticles is an established and efficient means to achieve controlled release of drugs. Incorporation of minocycline, an antibiotic with anti-inflammatory and neuroprotective properties, into biodegradable nanoparticles may therefore provide an efficient means to combat foreign body reactions to implanted electrodes in the brain. However, minocycline is commonly associated with poor encapsulation efficiencies and/or fast release rates due to its high solubility in water. Moreover, minocycline is unstable under conditions of low and high pH, heat and exposure to light, which exacerbate the challenges of encapsulation. In this work drug loaded PLGA nanoparticles were prepared by a modified emulsification-solvent-diffusion technique and characterized for size, drug encapsulation and in vitro drug release. A novel hydrophobic ion pair complex of minocycline, Ca(2+) ions and the anionic surfactant AOT was developed to protect minocycline from degradation and prolong its release. The optimized formulation resulted in particle sizes around 220 nm with an entrapment efficiency of 43% and showed drug release over 30 days in artificial cerebrospinal fluid. The present results constitute a substantial increase in release time compared to what has hitherto been achieved for minocycline and indicate that such particles might provide useful for sustained drug delivery in the CNS. PMID:26773599

  11. Description and validation of an AOT product over land at the 0.6 μm channel of the SEVIRI sensor onboard MSG

    Directory of Open Access Journals (Sweden)

    E. Bernard

    2011-11-01

    Full Text Available The Spinning Enhanced Visible and InfraRed Imager (SEVIRI aboard Meteosat Second Generation (MSG launched in 2003 by EUMETSAT is dedicated to the Nowcasting applications and Numerical Weather Prediction and to the provision of observations for climate monitoring and research. We use the data in visible and near infrared (NIR channels to derive the aerosol optical thickness (AOT over land. The algorithm is based on the assumption that the top of the atmosphere (TOA reflectance increases with the aerosol load. This is a reasonable assumption except in case of absorbing aerosols above bright surfaces. We assume that the minimum in a 14-days time series of the TOA reflectance is, once corrected from gaseous scattering and absorption, representative of the surface reflectance. The AOT and the aerosol model (a set of 5 models is used, are retrieved by matching the simulated TOA reflectance with the TOA reflectances measured by SEVIRI in its visible and NIR spectral bands.

    The high temporal resolution of the data acquisition by SEVIRI allows to retrieve the AOT every 15 min with a spatial resolution of 3 km at sub-satellite point, over the entire SEVIRI disk covering Europe, Africa and part of South America. The resulting AOT, a level 2 product at the native temporal and spatial SEVIRI resolutions, is presented and evaluated in this paper.

    The AOT has been validated using ground based measurements from AErosol RObotic NETwork (AERONET, a sun-photometer network, focusing over Europe for 3 months in 2006. The SEVIRI estimates correlate well with the AERONET measurements, r = 0.64, with a slight overestimate, bias = −0.017. The sources of errors are mainly the cloud contamination and the bad estimation of the surface reflectance. The temporal evolutions exhibited by both datasets show very good agreement which allows to conclude that the AOT Level 2 product from SEVIRI can be used to quantify the aerosol content and to monitor

  12. Thermal reversible gelation during phase separation of poly(N-isopropyl acrylamide)/water solution

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    By dynamic viscoelastic measurement for PNIPAM/water solution it has been found that below the phase separation temperature (about 32℃), the system is homogeneous fluid; while upon being heated to about 32℃, the solution undergoes phase separation and the storage modulus G′ increases sharply and exceeds the loss modulus G″, indicating the physical network formation during the phase separation. Based on the percolation model, the gel points Tgel were obtained by applying the dynamic scaling theory (DST) and Winter's criterion. The critical exponent n was also obtained to be 0.79 through DST, which is different from 0.67, the critical point of chemically crosslinked network predicted through DST. The obtained n value reflects the special property of physical network being different from chemical network.

  13. Thermal reversible gelation during phase separation of poly(N-isopropyl acrylamide)/water solution

    Institute of Scientific and Technical Information of China (English)

    曾钫[1; 刘新星[2; 童真[3; 杨燕银[4; 吴水珠[5

    2000-01-01

    By dynamic viscoelastic measurement for PNIPAM/water solution it has been found that below the phase separation temperature (about 32 ℃), the system is homogeneous fluid; while upon being heated to about 32 ℃, the solution undergoes phase separation and the storage modulus G’ increases sharply and exceeds the loss modulus G", indicating the physical network formation during the phase separation. Based on the percolation model, the gel points Tgel, were obtained by applying the dynamic scaling theory (DST) and winter’s criterion. The critical exponent n was also obtained to be 0.79 through DST, which is different from 0.67, the critical point of chemically crosslinked network predicted through DST. The obtained n value reflects the special property of physical network being different from chemical network.

  14. Evaluating the efficiency of different microfiltration and ultrafiltration membranes used as pretreatment for Red Sea water reverse osmosis desalination

    KAUST Repository

    Almashharawi, Samir

    2013-01-01

    Conventional processes are widely used as pretreatment for reverse osmosis (RO) desalination technology since its development. However, these processes require a large footprint and have some limitation issues such as difficulty to maintain a consistent silt density index, coagulation control at low total suspended solids, and management of higher waste sludge. Recently, there has been a rapid growth in the use of low-pressure membranes as pretreatment for RO systems replacing the conventional processes. However, despite the numerous advantages of using this integrated membrane system mainly providing good and stable water quality to RO membranes, many issues have to be addressed. The primary limitation is membrane fouling which reduces the permeate flux; therefore, higher pumping intensity is required to maintain a consistent volume of product. This paper aims to optimize the permeation flux and cleaning frequency by providing high permeate quality. Different low-pressure polyethersulfone membranes with different pore sizes ranging from 0.1 lm to 50 kDa were tested. Eight different filtration configurations have been applied including the variation of coagulant doses aiming to control membrane fouling. Results showed that all the configurations with/without coagulation, provided permeate with excellent water quality which improves the stability of RO performance. However, more stable fluxes with less-energy consumption were achieved by using the 0.1 lm and 100 kDa membranes with 1 mg/L FeCl3 coagulation. The use of UF membranes, having tight pores, without coagulation also proved to be an excellent option for Red Sea water RO pretreatment. © 2013 Desalination Publications.

  15. Forward Osmosis/Low Pressure Reverse Osmosis for Water Reuse: Removal of Organic Micropollutants, Fouling and Cleaning

    KAUST Repository

    Linares, Rodrigo

    2011-07-01

    Forward osmosis (FO) is a natural process in which a solution with high concentration of solutes is diluted when being in contact, through a semipermeable membrane, with a low concentration solution. This osmotic process has been demonstrated to be efficient to recover wastewater effluents while diluting a saline draw solution. Nevertheless, the study of the removal of micropollutants by FO is barely described in the literature. This research focuses on the removal of these substances spiked in a secondary wastewater effluent, while diluting water from the Red Sea, generating feed water that can be desalinated with a low pressure reverse osmosis (LPRO) system. Another goal of this work is to characterize the fouling of the FO membrane, and its effect on micropollutants rejection, as well as the membrane cleaning efficiency of different methods. When considering only FO with a clean membrane, the rejection of the hydrophilic neutral compounds was between 48.6% and 84.7%, for the hydrophobic neutrals the rejection ranged from 40.0% to 87.5%, and for the ionic compounds the rejections were between 92.9% and 96.5%. With a fouled membrane, the rejections were between 44.6% to 95.2%, 48.7% to 91.5% and 96.9% to 98.6%, respectively. These results suggest that, except for the hydrophilic neutral compounds, the rejection of the micropollutants is increased by the fouling layer, possibly due to the higher hydrophilicity of the FO fouled membrane compared to the clean one, the increased adsorption capacity and reduced mass transport capacity, membrane swelling, and the higher negative charge of the surface, related to the foulants. However, when coupled with low pressure reverse osmosis, the rejections for both, the clean and fouled membrane, increased above 98%. The fouling layer, after characterizing the wastewater effluent and the concentrated wastewater after the FO process, proved to be composed of biopolymers, which can be removed with air scouring during short periods

  16. On the importance of steady-state isotopic techniques for the investigation of the mechanism of the reverse water-gas-shift reaction.

    Science.gov (United States)

    Tibiletti, Daniele; Goguet, Alexandre; Meunier, Frederic C; Breen, John P; Burch, Robbie

    2004-07-21

    The formation and reactivity of surface intermediates in the reverse water-gas-shift reaction on a Pt/CeO2 catalyst are critically dependent on the reaction conditions so that conclusions regarding the reaction mechanism cannot be inferred using ex operando conditions. PMID:15263955

  17. Molecular characterization of the bacterial communities in the different compartments of a full-scale reverse-osmosis water purification plant

    NARCIS (Netherlands)

    Bereschenko, L.A.; Heilig, G.H.J.; Nederlof, M.M.; Loosdracht, van M.C.M.; Stams, A.J.M.; Euverink, G.J.W.

    2008-01-01

    The origin, structure, and composition of biofilms in various compartments of an industrial full-scale reverse-osmosis (RO) membrane water purification plant were analyzed by molecular biological methods. Samples were taken when the RO installation suffered from a substantial pressure drop and decre

  18. Molecular Characterization of the Bacterial Communities in the Different Compartments of a Full-Scale Reverse-Osmosis Water Purification Plant

    NARCIS (Netherlands)

    Bereschenko, L.A.; Heilig, G.H.J.; Nederlof, M.M.; Loosdrecht, M.C.M. van; Stams, A.J.M.; Euverink, G.J.W.

    2008-01-01

    The origin, structure, and composition of biofilms in various compartments of an industrial full-scale reverse-osmosis (RO) membrane water purification plant were analyzed by molecular biological methods. Samples were taken when the RO installation suffered from a substantial pressure drop and decre

  19. Spatial and Reversal Learning in the Morris Water Maze Are Largely Resistant to Six Hours of REM Sleep Deprivation Following Training

    Science.gov (United States)

    Walsh, Christine M.; Booth, Victoria; Poe, Gina R.

    2011-01-01

    This first test of the role of REM (rapid eye movement) sleep in reversal spatial learning is also the first attempt to replicate a much cited pair of papers reporting that REM sleep deprivation impairs the consolidation of initial spatial learning in the Morris water maze. We hypothesized that REM sleep deprivation following training would impair…

  20. 全自动在线血透水处理系统的设计%Design of automatic reverse osmosis water system

    Institute of Scientific and Technical Information of China (English)

    贺昕路; 顾伟新

    2015-01-01

    Objective:To design automatic reverse osmosis water system with new design idea of reverse osmosis water system, to make sure of the procedure. Methods:During the design, using microcomputer technology to control water preparation and disinfection. Results:Using MCU to control preparation of water and disinfection, in order to monitor water quality. If water quality exceeds the standard, the system will alarm and generate records. Conclusion: Using microcomputer technology to design Reverse osmosis water system, not only reducing artificial, but also to improve the safety and controllability, even the quality control of reverse osmosis water system.%目的:运用全新的水处理系统的设计思想,设计全自动血透水处理系统,确定水处理工艺流程。方法:在设计水处理过程中,应用单片机技术,对水处理系统的制水和消毒过程进行实时控制。结果:利用单片机技术在制水和消毒过程中,控制水处理系统,实时监控各个水质指标。当指标超标时系统自动报警并生成记录。结论:将单片机技术应用到水处理系统中,不仅降低了人工损耗,也提高了系统的安全性和可控性,同时对水处理系统进行质量控制。

  1. Feedwater production from river water with ion exchange and reverse osmosis. 10 years operation experience; Kesselspeisewasser-Erzeugung aus Flusswasser durch Ionenaustausch und Umkehrosmose. 10 Jahre Betriebserfahrungen

    Energy Technology Data Exchange (ETDEWEB)

    Wasel-Nielen, J.; Kluge, H. [InfraServ GmbH und Co. Hoechst KG, Frankfurt am Main (Germany)

    2000-07-01

    Since november 1988 the InfaServ Hoechst KG in Frankfurt am Main processes river water to be used as desalinated feedwater for high pressure steam boilers. Main purposes for the use of reverse osmosis were the reduction of waste water for regeneration and separation of organics contributing to boiler corrosion. Development of a new low pressure membrane reduced the energy demand. Biofouling proofed to be a main problem. Performance and cost are shown.

  2. Validation of an AOT product over land at the 0.6 μm channel of the SEVIRI sensor onboard MSG

    Directory of Open Access Journals (Sweden)

    E. Bernard

    2011-05-01

    Full Text Available The Spinning Enhanced Visible and InfraRed Imager (SEVIRI aboard Meteosat Second Generation (MSG launched in 2003 by EUMETSAT is dedicated to the Nowcasting applications and Numerical Weather Prediction and to provide information for climate monitoring and research. We use the data in visible and near infrared channels to derive the Aerosol Optical Thickness (AOT over land. The algorithm is based on the assumption that the Top Of the Atmosphere (TOA reflectance increases with the aerosol load. This is a reasonable assumption except in case of absorbing aerosols above bright surfaces. We assume that the minimum in a 14-day time series of the TOA reflectance is, once corrected from gaseous scattering and absorption, representative of the surface reflectance. The AOT and the aerosol model (a set of 5 models are used, are retrieved by matching the simulated TOA reflectance with the TOA reflectances measured by SEVIRI in its visible and Near Infra-Red (NIR spectral bands.

    The high temporal resolution of the data acquisition by SEVIRI allows to retrieve the AOT every 15 min with a spatial resolution of 3km at sub-satellite point, over the whole SEVIRI disk which covers Europe, Africa and part of South America. The resulting AOT, a Level 2 product at the same temporal and spatial resolution than SEVIRI, is presented and evaluated in this paper.

    The AOT has been validated using ground based measurements from AERONET, a sun-photometer network, focusing over Europe for 3 months in 2006. The SEVIRI estimates correlate well with the AERONET measurements, r = 0.64, with a slight underestimate, bias = −0.017. The sources of errors are mainly the cloud contamination and the bad estimation of the surface reflectance. The temporal evolutions exhibited by both dataset show very good agreement which allows to conclude that the AOT Level 2 product from SEVIRI can be used to quantify the aerosol content and to monitor its daily evolution

  3. Use of CuNi/YSZ and CuNi/SDC Catalysts for the Reverse Water Gas Shift Reaction

    Directory of Open Access Journals (Sweden)

    Maxime Lortie

    2015-01-01

    Full Text Available Cu50Ni50 nanoparticles were synthesized using a modified polyol method and deposited on samarium-doped ceria, SDC, and yttria-stabilized zirconia, YSZ, supports to form reverse water-gas shift, RWGS, catalysts. The best CO yields, obtained with the Cu50Ni50/SDC catalyst, were about 90% of the equilibrium CO yields. In contrast CO yields using Pt/SDC catalysts were equal to equilibrium CO yields at 700°C. Catalyst selectivity to CO was 100% at hydrogen partial pressures equal to CO2 partial pressures, 1 kPa, and decreased as methane was formed when the hydrogen partial pressure was 2 kPa or greater. The reaction results were explained using a combination of Eley-Rideal and Langmuir-Hinshelwood mechanisms that involved adsorption on the metal surface and the concentration of oxygen vacancies in the support. Finally the Cu50Ni50/SDC catalyst was found to be thermally stable for 48 hours at 600/700°C.

  4. Reverse Water-Gas Shift or Sabatier Methanation on Ni(110)? Stable Surface Species at Near-Ambient Pressure.

    Science.gov (United States)

    Roiaz, Matteo; Monachino, Enrico; Dri, Carlo; Greiner, Mark; Knop-Gericke, Axel; Schlögl, Robert; Comelli, Giovanni; Vesselli, Erik

    2016-03-30

    The interaction of CO, CO2, CO + H2, CO2 + H2, and CO + CO2 + H2 with the nickel (110) single crystal termination has been investigated at 10(-1) mbar in situ as a function of the surface temperature in the 300-525 K range by means of infrared-visible sum frequency generation (IR-vis SFG) vibrational spectroscopy and by near-ambient pressure X-ray photoelectron spectroscopy (NAP-XPS). Several stable surface species have been observed and identified. Besides atomic carbon and precursors for graphenic C phases, five nonequivalent CO species have been distinguished, evidencing the role of coadsorption effects with H and C atoms, of H-induced activation of CO, and of surface reconstruction. At low temperature, carbonate species produced by the interaction of CO2 with atomic oxygen, which stems from the dissociation of CO2 into CO + O, are found on the surface. A metastable activated CO2(-) species is also detected, being at the same time a precursor state toward dissociation into CO and O in the reverse water-gas shift mechanism and a reactive species that undergoes direct conversion in the Sabatier methanation process. Finally, the stability of ethylidyne is deduced on the basis of our spectroscopic observations. PMID:26954458

  5. Photoreactive surfactants: a facile and clean route to oxide and metal nanoparticles in reverse micelles.

    Science.gov (United States)

    de Oliveira, Rodrigo J; Brown, Paul; Correia, Gemima B; Rogers, Sarah E; Heenan, Richard; Grillo, Isabelle; Galembeck, André; Eastoe, Julian

    2011-08-01

    A new class of photoreactive surfactants (PRSs) is presented here, consisting of amphiphiles that can also act as reagents in photochemical reactions. An example PRS is cobalt 2-ethylhexanoate (Co(EH)(2)), which forms reverse micelles (RMs) in a hydrocarbon solvent, as well as mixed reversed micelles with the standard surfactant Aerosol-OT (AOT). Small-angle neutron scattering (SANS) data show that mixed AOT/PRS RMs have a spherical structure and size similar to that of pure AOT micelles. Excitation of the ligand-to-metal charge transfer (LMCT) band in the PRSs promotes electron transfer from PRS to associated metal counterions, leading to the generation of metal and metal-oxide nanoparticles inside the RMs. This work presents proof of concept for employing PRSs as precursors to obtain nearly monodisperse inorganic nanoparticles: here both Co(3)O(4) and Bi nanoparticles have been synthesized at high metal concentration (10(-2) M) by simply irradiating the RMs. These results point toward a new approach of photoreactive self-assembly, which represents a clean and straightforward route to the generation of nanomaterials.

  6. PdZnAl Catalysts for the Reactions of Water-Gas-Shift, Methanol Steam Reforming, and Reverse-Water-Gas-Shift

    Energy Technology Data Exchange (ETDEWEB)

    Dagle, Robert A.; Platon, Alexandru; Datye, Abhaya K.; Vohs, John M.; Wang, Yong; Palo, Daniel R.

    2008-03-07

    Pd/ZnO/Al2O3 catalysts were studied for water-gas-shift (WGS), methanol steam reforming, and reverse-water-gas-shift (RWGS) reactions. WGS activity was found to be dependent on the Pd:Zn ratio with a maximum activity obtained at approximately 0.50, which was comparable to that of a commercial Pt-based catalyst. The catalyst stability was demonstrated for 100 hours time-on-stream at a temperature of 3600C without evidence of metal sintering. WGS reaction rates were approximately 1st order with respect to CO concentration, and kinetic parameters were determined to be Ea = 58.3 kJ mol-1 and k0 = 6.1x107 min-1. During methanol steam reforming, the CO selectivities were observed to be lower than the calculated equilibrium values over a range of temperatures and steam/carbon ratios studied while the reaction rate constants were approximately of the same magnitude for both WGS and methanol steam reforming. These results indicate that although Pd/ZnO/Al2O3 are active WGS catalysts, WGS is not involved in methanol steam reforming. RWGS rate constants are on the order of about 20 times lower than that of methanol steam reforming, suggesting that RWGS reaction could be one of the sources for small amount of CO formation in methanol steam reforming.

  7. Synthesis of nanosilver particles by reverse micelle method and study of their bactericidal properties

    Science.gov (United States)

    Dung, Tran Thi Ngoc; Buu, Ngo Quoc; Viet Quang, Dang; Thi Ha, Huynh; Bang, Le Anh; Hoai Chau, Nguyen; Thi Ly, Nguyen; Trung, Nguyen Vu

    2009-09-01

    Nanosilver particles have been synthesized by the reverse micelle method, where AgNO3 was used as a silver ions source, NaBH4 and quercetin - as reducing agents, CTAB, SDOSS and AOT- as surfactants, while the stabilizer was Vietnamese chitosan. Studying the factors influencing the process of nanosilver particle formation, it was shown that the particle size of the nanosilver products depends on the concentration of the reaction components and their stoichiometric ratio. It was also shown that the reaction system using AOT surfactant is capable of producing nanosilver particles with smallest nanoparticles (phiav ~ 5 nm) and good particle-size distribution. The study on bactericidal activity of the nanosilver products indicated that the disinfecting solution with a nanosilver concentration of 3 ppm was able to inhibit all E.coli and Coliforms, TPC and fungi at 15 ppm, while Vibrio cholerae cells were inactivated completely with 0.5 ppm of nanosilver after 30 minutes exposition.

  8. Chemical Cleaning Analysis of Concentrated Water Reverse Osmosis Membrane%浓水反渗透膜元件化学清洗分析

    Institute of Scientific and Technical Information of China (English)

    冀美萍; 沈洪洋; 郭伟

    2011-01-01

    RO membrane fouling can cause system performance degradation, component of pressure difference between inlet and outlet, the increase of membrane components replacement. Periodic cleaning for the membrane is effective way to ensure the normal system operation and extend service life of elements of. Through analysis to the reason of concentrated reverse osmosis water system pollution, this article introduces the cleaning of reverse osmosis membrane method, and through two chemical cleaning data of dense water reverse osmosis system, it puts forward the optimal operation measures for concentrated water reverse osmosis system.%反渗透膜的污染会造成系统性能的下降、组件进出口压差的升高、膜元件的更换等。对膜进行定期的清洗是保证反渗透系统的正常运行、延长膜元件使用寿命的有效途径。通过对浓水反渗透系统污染原因的解读分析,讨论了反渗透膜清洗的方法,通过对浓水反渗透系统两次化学清洗数据进行对比分析,提出浓水反渗透系统优化运行的相关措施。

  9. Study on technologies of forward extraction of protein from tomato by reverse micelles%反胶束溶液萃取番茄凝集素的前萃工艺探讨

    Institute of Scientific and Technical Information of China (English)

    朱澄云; 王岩; 赵琨; 韩国华; 徐璐; 黄小丽

    2011-01-01

    Objective To explore the possibility of extraction of tomato lectin by aerosol OT (AOT)isooctane reverse micelles system. Methods The effects of pH, AOT concentration, KC1 concentration on the forward extraction rate were investigated and analyzed. Results At the condition of KC1 concentration 50 mmol·L-1 ,AOT concentration 110 mmol·L-1 and pH 9.0 ,the forward protein extraction rate achieved 46. 51%. Conclusions It is possible to extract tomato lectin using reversed micelles of AOT-isooctane.%目的 探讨用丁二酸二异辛酯磺酸钠(aerosl OT,AOT)-异辛烷反胶束体系萃取番茄凝集素的可能性.方法 考察并分析了反胶束溶液萃取番茄凝集素时的几种因素如pH值、表面活性剂AOT的浓度、KC1的浓度等对蛋白前萃率的影响.结果 在KC1浓度为50 mmol·L-1、AOT浓度为110 mmol·L-1及pH值9.0条件下前萃取率为46.51%.结论 以AOT-异辛烷反胶束溶液萃取番茄凝集素是可行的.

  10. A theoretical study of surface-structural sensitivity of the reverse water-gas shift reaction over Cu( hkl) surfaces

    Science.gov (United States)

    Wang, Gui-Chang; Jiang, Ling; Pang, Xian-Yong; Cai, Zun-Sheng; Pan, Yin-Ming; Zhao, Xue-Zhuang; Morikawa, Yoshitada; Nakamura, Junji

    2003-10-01

    The surface-structural sensitivity of the reverse water-gas shift (RWGS) reaction (CO 2 + H 2 → CO + H 2O) over the Cu(1 1 1), Cu(1 0 0), and Cu(1 1 0) surfaces has been studied by first-principle density functional calculations together with the UBI-QEP approach. Cluster models of the surface have been employed to simulate the adsorption of CO 2, H 2, H, O, OH, CO, and H 2O on the Cu( hkl) surfaces at low coverage. This sensitivity is determined by the difference in the activation barriers. It can be noticed that the most likely rate-determining step in RWGS reaction is the CO 2 dissociative adsorption, namely CO 2,g → CO s + O s. The trend in the calculated activation barriers for the reaction of CO 2 dissociative adsorption follows the order of Cu(1 1 0) reaction by copper is Cu(1 1 0), and the more densely packed Cu(1 1 1) surface is the least active among the Cu( hkl) surfaces studied here. As expected, the activation barriers for the recombinative reactions over Cu( hkl) are in the order of Cu(1 1 0) > Cu(1 0 0) > Cu(1 1 1), just opposite to the dissociative reactions. The interesting thing is that there is a good correlation between the adsorption bond length and the adsorption energy: The preferred adsorption site is the one with the shortest adsorption bond length. The present calculations are in good agreement with experimental observations.

  11. A Novelγ-Alumina Supported Fe-Mo Bimetallic Catalyst for Reverse Water Gas Shift Reaction

    Institute of Scientific and Technical Information of China (English)

    Abolfazl Gharibi Kharaji; Ahmad Shariati; Mohammad Ali Takassi

    2013-01-01

    In reverse water gas shift (RWGS) reaction CO2 is converted to CO which in turn can be used to pro-duce beneficial chemicals such as methanol. In the present study, Mo/Al2O3, Fe/Al2O3 and Fe-Mo/Al2O3 catalysts were synthesised using impregnation method. The structures of catalysts were studied using X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) method, inductively coupled plasma atomic emission spectrometer (ICP-AES), temperature programmed reduction (H2-TPR), CO chemisorption, energy dispersive X-ray (EDX) and scanning electron microscopy (SEM) techniques. Kinetic properties of all catalysts were investigated in a batch re-actor for RWGS reaction. The results indicated that Mo existence in structure of Fe-Mo/Al2O3 catalyst enhances its activity as compared to Fe/Al2O3. This enhancement is probably due to better Fe dispersion and smaller particle size of Fe species. Stability test of Fe-Mo/Al2O3 catalyst was carried out in a fixed bed reactor and a high CO yield for 60 h of time on stream was demonstrated. Fe2(MoO4)3 phase was found in the structures of fresh and used catalysts. TPR results also indicate that Fe2(MoO4)3 phase has low reducibility, therefore the Fe2(MoO4)3 phase significantly inhibits the reduction of the remaining Fe oxides in the catalyst, resulted in high stability of Fe-Mo/Al2O3 catalyst. Overall, this study introduces Fe-Mo/Al2O3 as a novel catalyst with high CO yield, almost no by-products and fairly stable for RWGS reaction.

  12. Decrease of droplet size of the reverse microemulsion 1-butyl-3-methylimidazolium tetrafluoroborate/Triton X-100/cyclohexane by addition of water.

    Science.gov (United States)

    Gao, Yanan; Hilfert, Liane; Voigt, Andreas; Sundmacher, Kai

    2008-03-27

    In the present contribution, results concerning the role of small amounts of water in the 1-butyl-3-methylimidazolium tetrafluoroborate (bmimBF4)-in-cyclohexane ionic liquid (IL) reverse microemulsions are reported. Dynamic light scattering (DLS) revealed that the size of microemulsion droplets decreased remarkably with increasing water content although water is often used as a polar component to swell reverse microemulsions. It was thus deduced that the number of microemulsion droplets was increased which was confirmed by conductivity measurements. The states of dissolved water were investigated by Fourier transform IR (FTIR) spectroscopic analysis showing that water molecules mainly act as bound water. 1H NMR along with two-dimensional rotating frame nuclear Overhauser effect (NOE) experiments (ROESY) further revealed that water molecules were mainly located in the periphery of the polar core of the microemulsion droplets and behave like a chock being inserted in the palisade layer of the droplet. This increased the curvature of the surfactant film at the IL/cyclohexane interface and thus led to the decrease of the microemulsion droplet size. The order of surfactant molecules arranged in the interface film was increased and thus induced a loss of entropy. Isothermal titration calorimetry (ITC) indicated that an enthalpy increase compensates for the loss of entropy during the process of microstructural transition. PMID:18318531

  13. A Pilot-scale Demonstration of Reverse Osmosis Unit for Treatment of Coal-bed Methane Co-produced Water and Its Modeling

    Institute of Scientific and Technical Information of China (English)

    钱智; 刘新春; 余志晟; 张洪勋; 琚宜文

    2012-01-01

    This study presents the first demonstration project in China for treatment of coal-bed methane(CBM) co-produced water and recycling.The work aims to provide a research and innovation base for solving the pollution problem of CBM extraction water.The reverse osmosis(RO) unit is applied to the treatment of CBM co-produced water.The results indicate that system operation is stable,the removal efficiency of the total dissolved solids(TDS) is as high as 97.98%,and Fe,Mn,and F-are almost completely removed.There is no suspended solids(SS) detected in the treated water.Furthermore,a model for the RO membrane separation process is developed to describe the quantitative relationship between key physical quantities-membrane length,flow velocity,salt concentration,driving pressure and water recovery rate,and the water recovery restriction equation based on mass balance is developed.This model provides a theoretical support for the RO system design and optimization.The TDS in the CBM co-produced water are removed to meet the "drinking water standards" and "groundwater quality standards" of China and can be used as drinking water,irrigation water,and livestock watering.In addition,the cost for treatment of CBM co-produced water is assessed,and the RO technology is an efficient and cost-effective treatment method to remove pollutants.

  14. Ionic liquid-in-oil microemulsions composed of double chain surface active ionic liquid as a surfactant: temperature dependent solvent and rotational relaxation dynamics of coumarin-153 in [Py][TF2N]/[C4mim][AOT]/benzene microemulsions.

    Science.gov (United States)

    Rao, Vishal Govind; Mandal, Sarthak; Ghosh, Surajit; Banerjee, Chiranjib; Sarkar, Nilmoni

    2012-07-19

    [Py][TF2N]-containing microemulsions is very small compared to the increase in solvation time on going from pure water to water-containing microemulsions. The average solvation time decreases with increasing R values at 298 K, but it shows only a small R dependence compared to microemulsions containing solvents capable of forming hydrogen bonds. We have also shown that the temperature has substantial effect on the solvent and rotational relaxation of C-153 in neat [Py][TF2N] compared to that of [Py][TF2N]/[C4mim][AOT]/benzene microemulsions at R = 0.69. PMID:22721252

  15. 反胶束体系萃取油莎豆蛋白的研究%EXTRACTION OF PROTEIN FROM CYPERUS ESCULENTUS BY REVERSE MICELLE SYSTEM

    Institute of Scientific and Technical Information of China (English)

    赵俊廷; 琚瑶; 陈复生

    2012-01-01

    AOT/异辛烷反胶束体系萃取油莎豆蛋白的前萃工艺进行了研究,考察了加料量、萃取温度、时间、AOT质量浓度、W0、KCl浓度、pH对蛋白质前萃率的影响,通过单因素试验和均匀设计试验,得到前萃的最佳工艺条件为:加料量0.05 g/mL,AOT质量浓度0.12 g/mL,W0为16,KCl浓度0.02 mol/L,pH7,萃取温度40℃,萃取时间86 min.%In this paper, we studied the forward extraction process of protein from Cyperus esculentus by AOT/isooctane reverse micelle system, and investigated the effects of addition amount, extraction temperature, time, AOT mass concentration, W0, KC1 concentration, and pH on the forward extraction rate. Single factor tests and uniform design tests showed that the optimum forward extraction conditions were as follows: addition amount 0.05 g/mL, AOT mass concentration 0.12 g/mL, W0 16, KC1 concentration 0.02 mol/L, pH 7, extraction time 86 min and temperature 40 ℃.

  16. Interfacial hydrodynamic instabilities driven by cross-diffusion in reverse microemulsions

    Science.gov (United States)

    Budroni, M. A.; Carballido-Landeira, J.; Intiso, A.; De Wit, A.; Rossi, F.

    2015-06-01

    When two microemulsions are put in contact in the gravity field along a horizontal contact line, cross-diffusion can trigger the transport of one species in the presence of a gradient in concentration of another species. We show here theoretically that such cross-diffusion effects can induce buoyancy-driven convective instabilities at the interface between two solutions of different compositions even when initially the less dense solution lies on top of the denser one. Two different sources of convective modes are identified depending whether positive or negative cross-diffusion is involved. We evidence the two predicted cross-diffusion driven instabilities experimentally using a two-layer stratification of Aerosol-OT (AOT) water-in-oil microemulsions solutions with different water or AOT composition.

  17. Bioluminescence-based method for measuring assimilable organic carbon in pretreatment water for reverse osmosis membrane desalination.

    Science.gov (United States)

    Weinrich, Lauren A; Schneider, Orren D; LeChevallier, Mark W

    2011-02-01

    A bioluminescence-based assimilable organic carbon (AOC) test was developed for determining the biological growth potential of seawater within the reverse osmosis desalination pretreatment process. The test uses Vibrio harveyi, a marine organism that exhibits constitutive luminescence and is nutritionally robust. AOC was measured in both a pilot plant and a full-scale desalination plant pretreatment.

  18. Main coolant pump resistance influence on single phase water reverse flow in the inverted U-tubes under natural circulation

    International Nuclear Information System (INIS)

    Based on nuclear power plant (NPP) best-estimate transient analysis with RELAP5/MOD3 code, the reactor point kinetics model in RELAP5/MOD3 code is replaced by the two-group, 3-D space and time dependent neutron kinetic model, and two-fluid model is replaced by drift flux model. A coupled three-dimensional physics and thermal-hydrodynamics model is used to develop its corresponding computing code, thus simulating natural circulation of single-phase flow for the PWR. In this paper, we report the forward and reverse flow distribution in the inverted U-tubes of the steam generator (SG) under some typical operating conditions in the natural circulation case, and analyze the influence of main coolant pump resistance on the forward and reverse flow distribution. The calculation results show that, the pressure drop between SG inlet and outlet plenum decreases, and the SG inlet and outlet mass flow decrease with an increased main coolant pump resistance, but net mass flux of reverse flow in inverted U-tubes, and the ratio of mass flow in all reverse flow tubes to that of main coolant pipeline increase, meanwhile, the secondary steam load is invariable in this process. (authors)

  19. Reversible Thermoassociation of Water-Soluble Polymers Thermoassociation réversible de polymères hydrosolubles

    Directory of Open Access Journals (Sweden)

    L'alloret F.

    2006-12-01

    Full Text Available In various industrial fields, water soluble polymers are commonly used as thickening agents to control the reology of aqueous fluids. Nevertheless, their properties are weakened as the temperature increases. In order to overcome this problem, the concept of thermoassociativewater soluble polymers was developed. Such new amphilic systems can be obtained by grafting on an hydrophilic backbone, side chains which become non water soluble above a Lower Critical Solution Temperature (LCST. Semidilute solutions of these copolymers present reversible thickening properties as the temperature increases and reaches a critical value, close to the side chains LCST. This behaviour can be related to the agregation of the grafts above their LCST, into hydrophobic microdomains , inducing the formation of a three dimensional network. At higher temperature, the viscosity of the solution sheared at a constant rate reaches a maximum value. This can be interpreted in terms of the reorganisation of the physical network under shear, from a structure with mainly intermolecular associationsto a system with an increasing number of intramolecular associations . Owing to the diversity of water soluble polymers exhibiting a phase separation on heating (LCST, different thermoassociativecopolymers were realized [1] and [2], using either polyelectrolyte or neutral hydrophilic backbone. In the aim of applications of such systems in the oilfield industry, copolymers containing 2-acrylamido 2-methyl propane sulfonic acid (AMPS were developed, using polyethylene oxide (PEO as LCST grafts. A general description of their rheological behaviour will be given here. Their properties can be controlled either by varying the solution characteristic (polymer concentration, salinity, etc. or by modifying the chemical structure of the copolymer (grafting ratio, molecular weight of the backbone, etc. . This rheological study showed the potentiality of the thermoassociativesystem, particularly

  20. Reverse Engineering

    International Nuclear Information System (INIS)

    This book gives descriptions of reverse engineering with principle and structure of it, including what reverse engineering is, prospect and concerned laws, basic knowledge for reverse engineering like manual and back to user mode, using tool such as IDA installation, dependency walker and dump bin, network monitoring and universal extractor. It indicates analysis of malignant code, giving explanations of file virus, spy ware, an infection way of malignant code, anti debugging like Find window.

  1. MesoDyn Simulation Study on Phase Diagram of Aerosol OT/isooctane/water System

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A simple model, i.e. sodium di(2-ethylhexyl) sulfosuccinate (AOT) represented by one-head and two-tail beads tied together by a harmonic spring and water or isooctane by one bead, was put forward via Dissipative Particles Dynamics (DPD) simulation method. Using the changes of interfacial tension between water and oil phase, a ternary phase diagram of AOT/water/isooctane system was drawn. From the simulation, one conclusion is shown that DPD simulation can be considered as an adjunct to experiments.

  2. Development and evaluation of a culture-independent method for source determination of fecal wastes in surface and storm waters using reverse transcriptase-PCR detection of FRNA coliphage genogroup gene sequences.

    Science.gov (United States)

    A complete method, incorporating recently improved reverse transcriptase-PCR primer/probe assays and including controls for determining interferences to phage recoveries from water sample concentrates and for detecting interferences to their analysis, was developed for the direct...

  3. Analysis and modeling of PEM fuel cell stack performance: Effect of in situ reverse water gas shift reaction and oxygen bleeding

    Science.gov (United States)

    Karimi, G.; Li, Xianguo

    In this study the performance of a polymer electrolyte membrane (PEM) fuel cell stack is analyzed with a mathematical model when the stack operates on hydrocarbon reformate gas as the anode feed stream. It is shown that the effect of carbon dioxide dilution of the hydrogen dominated reformate gas has a minimal impact on the stack performance. However, the CO-poisoning effect due to the in situ reverse water gas shift reaction in the anode feed stream could have a very serious adverse impact on the stack performance, especially at high current densities. Thermodynamic calculations indicate that the equilibrium concentrations of CO could be as high as 100 ppm, generated by the in situ reverse water gas shift reaction, under the typical conditions of PEM fuel cell operation; and are influenced by the stack operating temperature and water content of the reformate anode feed. This CO-poisoning of the stack performance is shown mitigated effectively by introducing about 0.5-1% oxygen to the anode feed.

  4. The synthesis of methanol and the reverse water-gas shift reaction over Zn-deposited Cu(100) and Cu(110) surfaces: comparison with Zn/Cu(111)

    Science.gov (United States)

    Nakamura, I.; Fujitani, T.; Uchijima, T.; Nakamura, J.

    1998-03-01

    The catalytic activity of Zn vapor-deposited Cu(100) and Cu(110) surfaces for methanol synthesis by the hydrogenation of CO 2 and the reverse water-gas shift reaction were studied using an XPS apparatus combined with a high-pressure flow reactor (18 atm). At a reaction temperature of 523 K, no promotional effect of Zn was observed for the methanol synthesis on both Zn/Cu(100) and Zn/Cu(110). The results were quite different from those for Zn/Cu(111), on which a significant promotion of methanol synthesis activity appeared to be due to the deposition of Zn, indicating that the promotional effect of Zn was sensitive to the surface structure of Cu. However, hysteresis was observed in the catalytic activity for methanol synthesis over the Zn/Cu(110) surface upon heating above 543 K in the reaction mixture. The activity became twice that measured before heating, which was close to the methanol synthesis activity of Zn/Cu(111) at the same Zn coverage. On the other hand, no such hysteresis was observed for the reverse water-gas shift reaction on Zn/Cu(110), indicating that the active site for methanol synthesis was not identical to that for the reverse water-gas shift reaction. In the post-reaction surface analysis, formate species was detected on both Zn/Cu(100) and Zn/Cu(110), whose coverage increased with increasing Zn coverage at 0< ΘZn<0.2. No correlation between the formate coverage and the methanol synthesis activity was obtained, which was in contrast to the results for Zn/Cu(111). Thus, the structure sensitivity observed in the catalytic activity of methanol synthesis over Zn-deposited Cu surfaces is ascribed to the significant difference in the reactivity of the formate intermediate.

  5. Synthesis of CuNi/C and CuNi/γ-Al2O3 Catalysts for the Reverse Water Gas Shift Reaction

    OpenAIRE

    Maxime Lortie; Rima Isaifan; Yun Liu; Sander Mommers

    2015-01-01

    A new polyol synthesis method is described in which CuNi nanoparticles of different Cu/Ni atomic ratios were supported on both carbon and gamma-alumina and compared with Pt catalysts using the reverse water gas shift, RWGS, reaction. All catalysts were highly selective for CO formation. The concentration of CH4 was less than the detection limit. Cu was the most abundant metal on the CuNi alloy surfaces, as determined by X-ray photoelectron spectroscopy, XPS, measurements. Only one CuNi al...

  6. Effects of water ageing on the mechanical properties of flax and glass fibre composites: Degradation and reversibility

    OpenAIRE

    Apolinario, Guilherme; Ienny, Patrick; Corn, Stéphane; Léger, Romain; Bergeret, Anne; Haudin, Jean-Marc

    2015-01-01

    Mechanical properties of flax-fibre reinforced composites (FFRC) are strongly affected by water ageing compared to glass-fibre reinforced composites (GFRC). This study highlights the influence of water absorption during immersion at 30°C on mechanical properties of unsaturated polyester reinforced composites. Flax-fibre composites showed a Fickian absorption behaviour and a water uptake 15 times higher than that of glass-fibre composites. GFRC's tensile modulus and maximum stress were slightl...

  7. Pilot study on arsenic removal from groundwater using a small-scale reverse osmosis system-Towards sustainable drinking water production.

    Science.gov (United States)

    Schmidt, Stefan-André; Gukelberger, Ephraim; Hermann, Mario; Fiedler, Florian; Großmann, Benjamin; Hoinkis, Jan; Ghosh, Ashok; Chatterjee, Debashis; Bundschuh, Jochen

    2016-11-15

    Arsenic contamination of groundwater is posing a serious challenge to drinking water supplies on a global scale. In India and Bangladesh, arsenic has caused the most serious public health issue in the world for nearly two decades. The aim of this work was to study an arsenic removal system based on reverse osmosis at pilot scale treating two different water sources from two different locations in the State of Bihar, India. For this purpose two villages, Bind Toli and Ramnagar in the Patna District were selected, both located very close to the river Ganga. The trials were conducted with aerated and non-aerated groundwater. It is the first time that the arsenic removal efficiency for aerated and non-aerated groundwater by reverse osmosis technology in combination with an energy-saving recovery system have been studied. As the principle of reverse osmosis requires a relatively high pressure, its energy demand is naturally high. By using an energy recovery system, this demand can be lowered, leading to an energy demand per liter permeate of 3-4Wh/L only. Due to high iron levels in the groundwater and as a consequence the precipitation of ferric (hydr)oxides, it was necessary to develop a granular media filter for the trials under aeration in order to protect the membrane from clogging. Two different materials, first locally available sand, and second commercially available anthracite were tested in the granular media filter. For the trials with aerated groundwater, total arsenic removal efficiency at both locations was around 99% and the arsenic concentration in permeate was in compliance with the WHO and National Indian Standard of 10μg/L. However, trials under anoxic conditions with non-aerated groundwater could not comply with this standard. Additionally a possible safe discharge of the reverse osmosis concentrate into an abandoned well was studied. It was observed that re-injection of reject water underground may offer a safe disposal option. However, long

  8. Pilot study on arsenic removal from groundwater using a small-scale reverse osmosis system-Towards sustainable drinking water production.

    Science.gov (United States)

    Schmidt, Stefan-André; Gukelberger, Ephraim; Hermann, Mario; Fiedler, Florian; Großmann, Benjamin; Hoinkis, Jan; Ghosh, Ashok; Chatterjee, Debashis; Bundschuh, Jochen

    2016-11-15

    Arsenic contamination of groundwater is posing a serious challenge to drinking water supplies on a global scale. In India and Bangladesh, arsenic has caused the most serious public health issue in the world for nearly two decades. The aim of this work was to study an arsenic removal system based on reverse osmosis at pilot scale treating two different water sources from two different locations in the State of Bihar, India. For this purpose two villages, Bind Toli and Ramnagar in the Patna District were selected, both located very close to the river Ganga. The trials were conducted with aerated and non-aerated groundwater. It is the first time that the arsenic removal efficiency for aerated and non-aerated groundwater by reverse osmosis technology in combination with an energy-saving recovery system have been studied. As the principle of reverse osmosis requires a relatively high pressure, its energy demand is naturally high. By using an energy recovery system, this demand can be lowered, leading to an energy demand per liter permeate of 3-4Wh/L only. Due to high iron levels in the groundwater and as a consequence the precipitation of ferric (hydr)oxides, it was necessary to develop a granular media filter for the trials under aeration in order to protect the membrane from clogging. Two different materials, first locally available sand, and second commercially available anthracite were tested in the granular media filter. For the trials with aerated groundwater, total arsenic removal efficiency at both locations was around 99% and the arsenic concentration in permeate was in compliance with the WHO and National Indian Standard of 10μg/L. However, trials under anoxic conditions with non-aerated groundwater could not comply with this standard. Additionally a possible safe discharge of the reverse osmosis concentrate into an abandoned well was studied. It was observed that re-injection of reject water underground may offer a safe disposal option. However, long

  9. Reversible Sterilization

    Science.gov (United States)

    Largey, Gale

    1977-01-01

    Notes that difficult questions arise concerning the use of sterilization for alleged eugenic and euthenic purposes. Thus, how reversible sterilization will be used with relation to the poor, mentally ill, mentally retarded, criminals, and minors, is questioned. (Author/AM)

  10. Vasectomy Reversal

    Medline Plus

    Full Text Available ... improving health. Hello, my name is Harris Nagler. I'm the Chairman of the Sol and Margaret ... Israel Medical Center in New York City. Today I'm going to perform a vasectomy reversal using ...

  11. Vasectomy Reversal

    Medline Plus

    Full Text Available ... Today we are going to go to the operating room and show you microsurgical vasectomy reversal. We ... vas and that will be examined under the operating- under the microscope to see if there’s sperm ...

  12. Vasectomy Reversal

    Medline Plus

    Full Text Available ... is a realistic option for many patients. Today we are going to go to the operating room and show you microsurgical vasectomy reversal. We start the procedure by localizing the site of ...

  13. Vasectomy Reversal

    Medline Plus

    Full Text Available Vasectomy Reversal Beth Israel Medical Center, New York, NY February 19, 2009 Welcome to this "OR Live" Webcast presentation premiering from Beth Israel Medical Center in New York City. ...

  14. Role of solubilized water in the reverse ionic liquid microemulsion of 1-butyl-3-methylimidazolium tetrafluoroborate/TX-100/benzene.

    Science.gov (United States)

    Gao, Yan'an; Li, Na; Zheng, Liqiang; Bai, Xiangtao; Yu, Li; Zhao, Xueyan; Zhang, Jin; Zhao, Mingwei; Li, Zhen

    2007-03-15

    The ionic liquid (IL) 1-butyl-3-methylimidazolium tetrafluoroborate (bmimBF4) can form nonaqueous microemulsions with benzene by the aid of nonionic surfactant TX-100. The effect of water on ionic liquid-in-oil (IL/O) microemulsions was studied, and it was shown that the addition of small amount of water to the IL microemulsion contributed to the stability of microemulsion and thus increased the amount of solubilized bmimBF4 in the microemulsion. The conductivity measurements also showed that the attractive interactions between IL microdroplets were weakened, that is, the IL/O microemulsion becomes more stable in the present of some water. Fourier transform IR was carried out to analyze the states of the added water, and the result showed that these water molecules mainly behaved as bound water and trapped water, indicating that the water molecules are located in the palisade layers of the IL/O microemulsion. Furthermore, 1H NMR and 19F NMR spectra suggested that the added water molecules built the hydrogen binding network of imidazolium cations and H2O, BF4- anion and H2O, and at the same time the electronegative oxygen atoms of the oxyethylene units of TX-100 and water in the palisade layers, which made the palisade layers more firm and thus increased the stability of the microemulsion. The study can help in further understanding the formation mechanism of microemulsions. In addition, the characteristic solubilization behavior of the added water can provide an aqueous interface film for hydrolysis reactions and therefore may be used as an ideal medium to prepare porous or hollow nanomaterials. PMID:17305388

  15. Determination of perfluorooctanoate and perfluorooctanesulfonate in water matrices by inline matrix elimination liquid chromatography with reversed phase separation and suppressed conductivity detection.

    Science.gov (United States)

    Subramanian, N Harihara; Manigandan, P; Wille, Andrea; Radhakrishnan, Ganga

    2011-09-01

    This work describes a new method for the determination of perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS) in water matrices by suppressed conductivity detection. Separation was achieved by isocratic elution on a reversed-phase column thermostated at 45°C using an aqueous mobile phase containing boric acid and acetonitrile. The PFOA and PFOS content in the water matrix were quantified by a pre-concentration technique. For the concentration range of 1 to 15 ng/mL and 2 to 30 ng/mL, the linear calibration curve for PFOA and PFOS yielded coefficients of determination (R(2)) of 0.9995 and 0.9985, respectively. The relative standard deviations were smaller than 1.5% for PFOA and PFOS. The retention-time precision of four consecutive 12 h injections was smaller than 0.641% and 0.818%, respectively. The presence of common divalent cations, such as calcium, magnesium, and iron in water matrices impairs PFOS recovery. This drawback was overcome by applying inline matrix elimination method. The optimized method was successfully applied for drinking water, ground water, and seawater samples.

  16. Analysis of iodinated haloacetic acids in drinking water by reversed-phase liquid chromatography/electrospray ionization/tandem mass spectrometry with large volume direct aqueous injection.

    Science.gov (United States)

    Li, Yongtao; Whitaker, Joshua S; McCarty, Christina L

    2012-07-01

    A large volume direct aqueous injection method was developed for the analysis of iodinated haloacetic acids in drinking water by using reversed-phase liquid chromatography/electrospray ionization/tandem mass spectrometry in the negative ion mode. Both the external and internal standard calibration methods were studied for the analysis of monoiodoacetic acid, chloroiodoacetic acid, bromoiodoacetic acid, and diiodoacetic acid in drinking water. The use of a divert valve technique for the mobile phase solvent delay, along with isotopically labeled analogs used as internal standards, effectively reduced and compensated for the ionization suppression typically caused by coexisting common inorganic anions. Under the optimized method conditions, the mean absolute and relative recoveries resulting from the replicate fortified deionized water and chlorinated drinking water analyses were 83-107% with a relative standard deviation of 0.7-11.7% and 84-111% with a relative standard deviation of 0.8-12.1%, respectively. The method detection limits resulting from the external and internal standard calibrations, based on seven fortified deionized water replicates, were 0.7-2.3 ng/L and 0.5-1.9 ng/L, respectively.

  17. Disinfection Byproduct Formation in Reverse-Osmosis Concentrated and Lyophilized Natural Organic Matter from a Drinking Water Source

    Science.gov (United States)

    Drinking water treatment and disinfection byproduct (DBP) research can be complicated by natural organic matter (NOM) temporal variability. NOM preservation by lyophilization (freeze-drying) has been long practiced to address this issue; however, its applicability for drinking wa...

  18. Possible role of laccase from Fusarium incarnatum UC-14 in bioremediation of Bisphenol A using reverse micelles system.

    Science.gov (United States)

    Chhaya, Urvish; Gupte, Akshaya

    2013-06-15

    Bisphenol A [2,2 bis (4 hydroxyphenyl) propane] is widely used in the variety of industrial and residential applications such as the synthesis of polymers including polycarbonates, epoxy resins, phenol resins, polyesters and polyacrylates. BPA has been recognized as an Endocrine Disrupting Chemicals (EDC), thus it is necessary to assess its biodegradability or fate in the natural environment. In general, environmental pollutant such as BPA does not dissolve in aqueous media, owing to their high hydrophobicity, and hence non-aqueous catalysis can be employed to enhance biodegradability of phenolic environmental pollutant. Purified laccase hosted in reverse micelles using ternary system of isooctane: AOT [Bis (2-ethylhexyl) sulphosuccinate sodium salt)]:water having hydration ratio (Wo) of 30 with protein concentration of 43.5 μg/ml was found to eliminate 91.43% of 200 ppm of Bisphenol A at 50 °C, pH-6.0 when incubated with laccase/Reverse Micelles system for 75 min. GC-MS analysis of isooctane soluble fractions detected the presence of 4,4'-(2 hydroxy propane 1,2 diyl) diphenol, bis (4-hydroxylphenyl) butenal and 2-(1-(4-hydroxyphenyl) vinyl) pent-2-enal indicated degradation of BPA by two oxidation steps and one ring opening step (C-C bond cleavage). Laccase/RM system exhibited several advantages for the oxidative degradation of hydrophobic phenols mainly because of the solubility of either enzyme or substrate was improved in organic media and the stable activity of laccase in organic media was achieved. PMID:23611799

  19. Time reversal communication system

    Science.gov (United States)

    Candy, James V.; Meyer, Alan W.

    2008-12-02

    A system of transmitting a signal through a channel medium comprises digitizing the signal, time-reversing the digitized signal, and transmitting the signal through the channel medium. The channel medium may be air, earth, water, tissue, metal, and/or non-metal.

  20. Lidar Observations of Low-level Wind Reversals over the Gulf of Lion and Characterization of Their Impact on the Water Vapour Variability

    Science.gov (United States)

    Di Girolamo, Paolo; Flamant, Cyrille; Cacciani, Marco; Summa, Donato; Stelitano, Dario; Mancini, Ignazio; Richard, Evelyne; Ducrocq, Véronique; Nuret, Mathieu; Said, Frédérique

    2016-06-01

    Water vapour measurements from a ground-based Raman lidar and an airborne differential absorption lidar, complemented by high resolution numerical simulations from two mesoscale models (Arome-WMED and MESO-NH), are considered to investigate transition events from Mistral/Tramontane to southerly marine flow taking place over the Gulf of Lion in Southern France in the time frame September-October 2012, during the Hydrological Cycle in the Mediterranean Experiment (HyMeX) Special Observation Period 1 (SOP1). Low-level wind reversals associated with these transitions are found to have a strong impact on water vapour transport, leading to a large variability of the water vapour vertical and horizontal distribution. The high spatial and temporal resolution of the lidar data allow to monitor the time evolution of the three-dimensional water vapour field during these transitions from predominantly northerly Mistral/Tramontane flow to a predominantly southerly flow, allowing to identify the quite sharp separation between these flows, which is also quite well captured by the mesoscale models.

  1. Behavior of pharmaceuticals and drugs of abuse in a drinking water treatment plant (DWTP) using combined conventional and ultrafiltration and reverse osmosis (UF/RO) treatments

    Energy Technology Data Exchange (ETDEWEB)

    Boleda, Ma Rosa [AGBAR-Aiguees de Barcelona, Gral Batet 5-7, 08028 Barcelona (Spain); Galceran, Ma Teresa [University of Barcelona, Department Analytical Chemistry, Av. Diagonal 647, 08028 Barcelona (Spain); Ventura, Francesc, E-mail: fventura@agbar.es [AGBAR-Aiguees de Barcelona, Gral Batet 5-7, 08028 Barcelona (Spain)

    2011-06-15

    The behavior along the potabilization process of 29 pharmaceuticals and 12 drugs of abuse identified from a total of 81 compounds at the intake of a drinking water treatment plant (DWTP) has been studied. The DWTP has a common treatment consisting of dioxychlorination, coagulation/flocculation and sand filtration and then water is splitted in two parallel treatment lines: conventional (ozonation and carbon filtration) and advanced (ultrafiltration and reverse osmosis) to be further blended, chlorinated and distributed. Full removals were reached for most of the compounds. Iopromide (up to 17.2 ng/L), nicotine (13.7 ng/L), benzoylecgonine (1.9 ng/L), cotinine (3.6 ng/L), acetaminophen (15.6 ng/L), erythromycin (2.0 ng/L) and caffeine (6.0 ng/L) with elimination efficiencies {>=}94%, were the sole compounds found in the treated water. The advanced treatment process showed a slightly better efficiency than the conventional treatment to eliminate pharmaceuticals and drugs of abuse. - Highlights: > The presence of pharmaceuticals and drugs of abuse in surface water was demonstrated. > Elimination in both potabilization processes reached levels >99% for most compounds. > Four pharmaceuticals and three drugs of abuse survived the potabilization process. - The efficiency of potabilization processes to eliminate or transform pharmaceuticals and illicit drugs is evaluated.

  2. Behavior of pharmaceuticals and drugs of abuse in a drinking water treatment plant (DWTP) using combined conventional and ultrafiltration and reverse osmosis (UF/RO) treatments

    International Nuclear Information System (INIS)

    The behavior along the potabilization process of 29 pharmaceuticals and 12 drugs of abuse identified from a total of 81 compounds at the intake of a drinking water treatment plant (DWTP) has been studied. The DWTP has a common treatment consisting of dioxychlorination, coagulation/flocculation and sand filtration and then water is splitted in two parallel treatment lines: conventional (ozonation and carbon filtration) and advanced (ultrafiltration and reverse osmosis) to be further blended, chlorinated and distributed. Full removals were reached for most of the compounds. Iopromide (up to 17.2 ng/L), nicotine (13.7 ng/L), benzoylecgonine (1.9 ng/L), cotinine (3.6 ng/L), acetaminophen (15.6 ng/L), erythromycin (2.0 ng/L) and caffeine (6.0 ng/L) with elimination efficiencies ≥94%, were the sole compounds found in the treated water. The advanced treatment process showed a slightly better efficiency than the conventional treatment to eliminate pharmaceuticals and drugs of abuse. - Highlights: → The presence of pharmaceuticals and drugs of abuse in surface water was demonstrated. → Elimination in both potabilization processes reached levels >99% for most compounds. → Four pharmaceuticals and three drugs of abuse survived the potabilization process. - The efficiency of potabilization processes to eliminate or transform pharmaceuticals and illicit drugs is evaluated.

  3. Two-step preparation of nano-scaled magnetic chitosan particles using Triton X-100 reversed-phase water-in-oil microemulsion system

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Zhengkun; Jiang, Feihong [College of Food Science and Engineering, Northwest A and F University, Yangling, Shaanxi 712100 (China); Lee, Tung-Ching, E-mail: lee@aesop.rutgers.edu [Department of Food Science, Rutgers, the State University of New Jersey, 65 Dudley Road, New Brunswick, NJ 08901 (United States); Yue, Tianli, E-mail: yuetl305@nwsuaf.edu.cn [College of Food Science and Engineering, Northwest A and F University, Yangling, Shaanxi 712100 (China)

    2013-12-25

    Highlights: •A new two-step route for nano-scaled magnetic chitosan particles preparation. •Triton X-100 reversed-phase microemulsion system was used for chitosan coating. •Narrow size distribution of magnetic chitosan nanoparticles was achieved. •Quantitative evaluation of recoverability for the magnetic chitosan nanoparticles. -- Abstract: A new two-step route for the preparation of nano-scaled magnetic chitosan particles has been developed, different from reported one-step in situ preparation and two-step preparation method of reversed-phase suspension, Triton X-100 reversed-phase water-in-oil microemulsion encapsulation method was employed in coating the pre-prepared Fe{sub 3}O{sub 4} nanoparticles with chitosan. The resultant magnetic chitosan particles owned a narrow size distribution ranging from 50 to 92 nm. X-ray diffraction patterns (XRD) indicated that the chitosan coating procedure did not change the spinal structure of Fe{sub 3}O{sub 4} magnetic nanoparticles. The results of Fourier transform infrared (FTIR) analysis and thermogravimetric analysis (TGA) demonstrated that the chitosan was coated on Fe{sub 3}O{sub 4} nanoparticles and its average mass content was ∼50%. The saturated magnetization of the magnetic Fe{sub 3}O{sub 4}/chitosan nanoparticles reached 18.62 emu/g, meanwhile, the nanoparticles showed the characteristics of superparamagnetism. The magnetic chitosan nanoparticles showed a high recoverability of 99.99% in 10 min when pH exceeded 4. The results suggested that the as-prepared magnetic chitosan particles were nano-scaled with a narrow size distribution and a high recoverability.

  4. Two-step preparation of nano-scaled magnetic chitosan particles using Triton X-100 reversed-phase water-in-oil microemulsion system

    International Nuclear Information System (INIS)

    Highlights: •A new two-step route for nano-scaled magnetic chitosan particles preparation. •Triton X-100 reversed-phase microemulsion system was used for chitosan coating. •Narrow size distribution of magnetic chitosan nanoparticles was achieved. •Quantitative evaluation of recoverability for the magnetic chitosan nanoparticles. -- Abstract: A new two-step route for the preparation of nano-scaled magnetic chitosan particles has been developed, different from reported one-step in situ preparation and two-step preparation method of reversed-phase suspension, Triton X-100 reversed-phase water-in-oil microemulsion encapsulation method was employed in coating the pre-prepared Fe3O4 nanoparticles with chitosan. The resultant magnetic chitosan particles owned a narrow size distribution ranging from 50 to 92 nm. X-ray diffraction patterns (XRD) indicated that the chitosan coating procedure did not change the spinal structure of Fe3O4 magnetic nanoparticles. The results of Fourier transform infrared (FTIR) analysis and thermogravimetric analysis (TGA) demonstrated that the chitosan was coated on Fe3O4 nanoparticles and its average mass content was ∼50%. The saturated magnetization of the magnetic Fe3O4/chitosan nanoparticles reached 18.62 emu/g, meanwhile, the nanoparticles showed the characteristics of superparamagnetism. The magnetic chitosan nanoparticles showed a high recoverability of 99.99% in 10 min when pH exceeded 4. The results suggested that the as-prepared magnetic chitosan particles were nano-scaled with a narrow size distribution and a high recoverability

  5. Evaluating the Efficiency of Different Microfiltration and Ultrafiltration Membranes Used as Pre-treatment for Reverse Osmosis Desalination of Red Sea Water

    KAUST Repository

    AlMashharawi, Samer

    2011-07-01

    . Collectively, results showed that all eight configurations provided permeate with excellent water quality to be fed to reverse osmosis membrane. However, using the 0.1 μm and 100kDa membranes with 1 mg/l FeCl3 concentration, respectively, steadier fluxes correspond to less increment of pumping intensity and better water quality was achieved.

  6. Synthesis of CuNi/C and CuNi/γ-Al2O3 Catalysts for the Reverse Water Gas Shift Reaction

    Directory of Open Access Journals (Sweden)

    Maxime Lortie

    2015-01-01

    Full Text Available A new polyol synthesis method is described in which CuNi nanoparticles of different Cu/Ni atomic ratios were supported on both carbon and gamma-alumina and compared with Pt catalysts using the reverse water gas shift, RWGS, reaction. All catalysts were highly selective for CO formation. The concentration of CH4 was less than the detection limit. Cu was the most abundant metal on the CuNi alloy surfaces, as determined by X-ray photoelectron spectroscopy, XPS, measurements. Only one CuNi alloy catalyst, Cu50Ni50/C, appeared to be as thermally stable as the Pt/C catalysts. After three temperature cycles, from 400 to 700°C, the CO yield at 700°C obtained using the Cu50Ni50/C catalyst was comparable to that obtained using a Pt/C catalyst.

  7. Reaction mechanism of the reverse water-gas shift reaction using first-row middle transition metal catalysts L'M (M = Fe, Mn, Co): a computational study.

    Science.gov (United States)

    Liu, Cong; Cundari, Thomas R; Wilson, Angela K

    2011-09-19

    The mechanism of the reverse water-gas shift reaction (CO(2) + H(2) → CO + H(2)O) was investigated using the 3d transition metal complexes L'M (M = Fe, Mn, and Co, L' = parent β-diketiminate). The thermodynamics and reaction barriers of the elementary reaction pathways were studied with the B3LYP density functional and two different basis sets: 6-311+G(d) and aug-cc-pVTZ. Plausible reactants, intermediates, transition states, and products were modeled, with different conformers and multiplicities for each identified. Different reaction pathways and side reactions were also considered. Reaction Gibbs free energies and activation energies for all steps were determined for each transition metal. Calculations indicate that the most desirable mechanism involves mostly monometallic complexes. Among the three catalysts modeled, the Mn complex shows the most favorable catalytic properties. Considering the individual reaction barriers, the Fe complex shows the lowest barrier for activation of CO(2). PMID:21838224

  8. Preconcentration and Speciation of Trace Mercury Compounds in Water Sample Using Dithizonates Extraction and Reverse Phased Liquid Chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Suh, J.K.; Cho, K.H. [Korea Research Institute of Standards and Science, Taejon (Korea); Lee, S.H. [Kyungpook National University, Taegu (Korea)

    2000-02-01

    A rapid preconcentration method was developed for the speciation of the trace mercury compounds in water sample. The mercury compounds were extracted and preconcentrated simply as their dithizone complexes by passing through the dithizone impregnated ultra-high molecular weight polyethylene (CHMWPE) membrane solvent inlet filter following sonification in methanol solvent. The concentrated dithizonates were separated by liquid chromatography on a C{sub 18} column. Complete resolution was obtained between methyl-, ethyl-, phenyl-, and inorganic mercury with a mobile phase of 0.05 M acetate buffer (pH=4)/THF/methanol(3:5:2). The separated mercury chelates were detected by spectrophotometrically at 475 nm. The proposed method was successfully applied to the speciation of mercury compounds in waste water with detection limit at the subnanogram/mL level. (author). 15 refs., 2 tabs., 8 figs.

  9. Neural network implementation for a reversal procedure for water and dry matter estimation on plant leaves using selected LED wavelengths.

    Science.gov (United States)

    Conejo, Elian; Frangi, Jean-Pierre; de Rosny, Gilles

    2015-06-10

    An inversion method based on a neural network was used to estimate water and dry matter contents on plant leaves, from transmittance and reflectance measurements, using light emitting diodes (LEDs) at specific wavelengths in NIR and FIR. The preliminary results for the predicted water content by the neural network method showed a RMSE value of 0.0027 g/cm(2) and |σ| value of approximately 3.53%, computed on 127 plant leaf samples over 51 species. Dry matter estimation also was performed, which showed potential implementation after future improvements. We believe this inversion method could be implemented in a portable system based on any silicon platform with the capability to perform in situ measurements on plant tissue. PMID:26192847

  10. RO膜反渗透水处理技术在煤矿的应用%Application of RO reverses osmosis membrane water treatment technology in coal mine

    Institute of Scientific and Technical Information of China (English)

    秦俏; 周吾昆; 张政

    2015-01-01

    using RO reverse osmosis water treatment technology for the advanced treatment, provides a more secure and efficient method to reduce the funds loss caused by hydraulic support and other large hydraulic equipment corrosion. The method, compared with the traditional method, has the high impurity removal rate, the neutrality of Yin and Yang ion is good, the water after treatment can reach the standard of pure water ,and can be drunk directly.%利用RO膜精密反渗透水处理技术对矿井水进行深度处理,为有效降低液压支架等大型液压设备腐蚀锈蚀造成的资金损耗提供了一种更加安全高效的方法与工艺。其处理方法与传统方法相比杂质去除率高、阴阳离子中和性好、处理后的水达到纯净水标准可直接饮用。

  11. Pilot-scale study on the treatment of basal aquifer water using ultrafiltration, reverse osmosis and evaporation/crystallization to achieve zero-liquid discharge.

    Science.gov (United States)

    Loganathan, Kavithaa; Chelme-Ayala, Pamela; Gamal El-Din, Mohamed

    2016-01-01

    Basal aquifer water is deep groundwater found at the bottom of geological formations, underlying bitumen-saturated sands. Some of the concerns associated with basal aquifer water at the Athabasca oil sands are the high concentrations of hardness-causing compounds, alkalinity, and total dissolved solids. The objective of this pilot-scale study was to treat basal aquifer water to a quality suitable for its reuse in the production of synthetic oil. To achieve zero-liquid discharge (ZLD) conditions, the treatment train included chemical oxidation, polymeric ultrafiltration (UF), reverse osmosis (RO), and evaporation-crystallization technologies. The results indicated that the UF unit was effective in removing solids, with UF filtrate turbidity averaging 2.0 NTU and silt density index averaging 0.9. Membrane autopsies indicated that iron was the primary foulant on the UF and RO membranes. Laboratory and pilot-scale tests on RO reject were conducted to determine the feasibility of ZLD crystallization. Due to the high amounts of calcium, magnesium, and bicarbonate in the RO reject, softening of the feed was required to avoid scaling in the evaporator. Crystals produced throughout the testing were mainly sodium chloride. The results of this study indicated that the ZLD approach was effective in both producing freshwater and minimizing brine discharges.

  12. Synthesis and Characterization of Poly(arylene ether sulfone)s for Reverse Osmosis Water Purification and Gas Separation Membranes

    OpenAIRE

    Sundell, Benjamin James

    2014-01-01

    Crosslinking is an effective technique for increasing the salt rejection of water purification membranes and the selectivity of gas separation membranes. An abundance of monomers, telechelic oligomers, and novel polymers were synthesized for use as separation membranes. These materials were often imbued with crosslinking functionalities to increase their performance during testing at the University of Texas-Austin. Crosslinking of sulfonated poly(arylene ether sulfone) oligomers was stud...

  13. Preparation of ZrO2 nano-particles by the hydrolysis of ZrOCl2 solution in the reverse micelles

    Institute of Scientific and Technical Information of China (English)

    Chensha Li; Tongxiang Liang; Tianyong Luo

    2006-01-01

    Zirconia nano-particles have been produced by the hydrolysis of ZrOGl2 solution in the reverse micelles of a liquid-liquid two-phase system, in which sodium bis(2-ethylhexyl) sulfosuccinite (AOT) and toluene were chosen as the surfactant and organic phase, respectively. The reverse micelles prevented the aggregation of primary particles and reduced the diameters of zirconia nanoparticles. Superfine zirconia powders soft-aggregated by the zirconia nano-particles were obtained. The diameters of zirconia nanoparticles were influenced by the quantity of the surfactant.

  14. A Comparison of Seasonal and Interannual Variability of Soil Dust Aerosols Over the Atlantic Ocean as Inferred by the Toms AI and AVHRR AOT Retrievals

    Science.gov (United States)

    Cakmur, R. V.; Miller, R. L.; Tegen, Ina; Hansen, James E. (Technical Monitor)

    2001-01-01

    The seasonal cycle and interannual variability of two estimates of soil (or 'mineral') dust aerosols are compared: Advanced Very High Resolution Radiometer (AVHRR) aerosol optical thickness (AOT) and Total Ozone Mapping Spectrometer (TOMS) aerosol index (AI), Both data sets, comprising more than a decade of global, daily images, are commonly used to evaluate aerosol transport models. The present comparison is based upon monthly averages, constructed from daily images of each data set for the period between 1984 and 1990, a period that excludes contamination from volcanic eruptions. The comparison focuses upon the Northern Hemisphere subtropical Atlantic Ocean, where soil dust aerosols make the largest contribution to the aerosol load, and are assumed to dominate the variability of each data set. While each retrieval is sensitive to a different aerosol radiative property - absorption for the TOMS AI versus reflectance for the AVHRR AOT - the seasonal cycles of dust loading implied by each retrieval are consistent, if seasonal variations in the height of the aerosol layer are taken into account when interpreting the TOMS AI. On interannual time scales, the correlation is low at most locations. It is suggested that the poor interannual correlation is at least partly a consequence of data availability. When the monthly averages are constructed using only days common to both data sets, the correlation is substantially increased: this consistency suggests that both TOMS and AVHRR accurately measure the aerosol load in any given scene. However, the two retrievals have only a few days in common per month so that these restricted monthly averages have a large uncertainty. Calculations suggest that at least 7 to 10 daily images are needed to estimate reliably the average dust load during any particular month, a threshold that is rarely satisfied by the AVHRR AOT due to the presence of clouds in the domain. By rebinning each data set onto a coarser grid, the availability of

  15. Validation and scopolamine-reversal of latent learning in the water maze utilizing a revised direct platform placement procedure.

    Science.gov (United States)

    Malin, David H; Schaar, Krystal L; Izygon, Jonathan J; Nghiem, Duyen M; Jabitta, Sikirat Y; Henceroth, Mallori M; Chang, Yu-Hsuan; Daggett, Jenny M; Ward, Christopher P

    2015-08-01

    The Morris water maze is routinely used to explore neurobiological mechanisms of working memory. Humans can often acquire working memory relevant to performing a task by mere sensory observation, without having to actually perform the task followed by reinforcement. This can be modeled in the water maze through direct placement of a rat on the escape platform so that it can observe the location, and then assessing the subject's performance in swimming back to the platform. However, direct placement procedures have hardly been studied for two decades, reflecting a controversy about whether direct placement resulted in sufficiently rapid and direct swims back to the platform. In the present study, utilizing revised training methods, a more comprehensive measure of trajectory directness, a more rigorous sham-trained control procedure and an optimal placement-test interval, rats swam almost directly back to the platform in under 4s, significantly more quickly and directly than sham-trained subjects. Muscarinic cholinergic mechanisms, which are inactivated by scopolamine, are essential to memory for standard learning paradigms in the water maze. This experiment determined whether this would also be true for latent learning. ANOVA revealed significant negative effects of scopolamine on both speed and accuracy of trajectory, as well as significant positive effects of direct placement training vs. sham-training. In a probe trial, placement-trained animals without scopolamine spent significantly more time and path length in the target quadrant than trained rats with scopolamine and sham-trained rats without scopolamine. Scopolamine impairments are likely due to effects on memory, since the same dose had little effect on performance with a visible platform. The revised direct placement model offers a means of further comparing the neural mechanisms of latent learning with those of standard instrumental learning. PMID:26033423

  16. Validation and scopolamine-reversal of latent learning in the water maze utilizing a revised direct platform placement procedure.

    Science.gov (United States)

    Malin, David H; Schaar, Krystal L; Izygon, Jonathan J; Nghiem, Duyen M; Jabitta, Sikirat Y; Henceroth, Mallori M; Chang, Yu-Hsuan; Daggett, Jenny M; Ward, Christopher P

    2015-08-01

    The Morris water maze is routinely used to explore neurobiological mechanisms of working memory. Humans can often acquire working memory relevant to performing a task by mere sensory observation, without having to actually perform the task followed by reinforcement. This can be modeled in the water maze through direct placement of a rat on the escape platform so that it can observe the location, and then assessing the subject's performance in swimming back to the platform. However, direct placement procedures have hardly been studied for two decades, reflecting a controversy about whether direct placement resulted in sufficiently rapid and direct swims back to the platform. In the present study, utilizing revised training methods, a more comprehensive measure of trajectory directness, a more rigorous sham-trained control procedure and an optimal placement-test interval, rats swam almost directly back to the platform in under 4s, significantly more quickly and directly than sham-trained subjects. Muscarinic cholinergic mechanisms, which are inactivated by scopolamine, are essential to memory for standard learning paradigms in the water maze. This experiment determined whether this would also be true for latent learning. ANOVA revealed significant negative effects of scopolamine on both speed and accuracy of trajectory, as well as significant positive effects of direct placement training vs. sham-training. In a probe trial, placement-trained animals without scopolamine spent significantly more time and path length in the target quadrant than trained rats with scopolamine and sham-trained rats without scopolamine. Scopolamine impairments are likely due to effects on memory, since the same dose had little effect on performance with a visible platform. The revised direct placement model offers a means of further comparing the neural mechanisms of latent learning with those of standard instrumental learning.

  17. Reversible, Selective Trapping of Perchlorate from Water in Record Capacity by a Cationic Metal-Organic Framework.

    Science.gov (United States)

    Colinas, Ian R; Silva, Rachel C; Oliver, Scott R J

    2016-02-16

    We report the capture of ppm-level aqueous perchlorate in record capacity and kinetics via the complete anion exchange of a cationic metal-organic framework. Ambient conditions were used for both the synthesis of silver 4,4'-bipyridine nitrate (SBN) and the exchange, forming silver 4,4'-bipyridine perchlorate (SBP). The exchange was complete within 90 min, and the capacity was 354 mg/g, representing 99% removal. These values are greater than current anion exchangers such as the resins Amberlite IRA-400 (249 mg/g), Purolite A530E (104 mg/g), and layered double hydroxides (28 mg/g). Moreover, unlike resins and layered double hydroxides, SBN is fully reusable and displays 96% regeneration to SBN in nitrate solution, with new crystal formation allowing the indefinite cycling for perchlorate. We show seven cycles as proof of concept. Perchlorate contamination of water represents a serious health threat because it is a thyroid endocrine disruptor. This noncomplexing anionic pollutant is significantly mobile and environmentally persistent. Removal of other anionic pollutants from water such as chromate, pertechnetate, or arsenate may be possible by this methodology. PMID:26765213

  18. Reversible dementias

    OpenAIRE

    Tripathi, Manjari; Vibha, Deepti

    2009-01-01

    In recent years, more attention has been given to the early diagnostic evaluation of patients with dementia which is essential to identify patients with cognitive symptoms who may have treatable conditions. Guidelines suggest that all patients presenting with dementia or cognitive symptoms should be evaluated with a range of laboratory tests, and with structural brain imaging with computed tomography (CT) or magnetic resonance imaging (MRI). While many of the disorders reported as ‘reversible...

  19. THE DEVELOPMENT OF CONTROL SYSTEM OF REVERSE OSMOSIS WATER TREATMENT UNIT%反渗透水处理设备电导率控制系统的研制

    Institute of Scientific and Technical Information of China (English)

    李修仁; 秦旭达; 哈鼎文

    2001-01-01

    本文介绍了一种模糊控制器,应用于反渗透水处理设备中,可实现电导率实时自动控制,提高了反渗透水处理过程中设备工作效率和水的利用率。%This paper introduces a fuzzy controller that authors designed. It was applied to reverse osmosis water treatment unit, realizing the conductivity auto-controlled and raising the working efficiency of the equipment and the utilization ratio of water remarkably in the reverse osmosis process.

  20. Enzymatic hydrolysis of penicillin and in situ product separation in thermally induced reversible phase-separation of ionic liquids/water mixture.

    Science.gov (United States)

    Mai, Ngoc Lan; Koo, Yoon-Mo

    2014-09-01

    Enzymatic hydrolysis of penicillin G to produce 6-aminopenicillanic acid, key intermediate for the production of semisynthetic β-lactam antibiotics, is one of the most relevant example of industrial implementation of biocatalysts. The hydrolysis reaction is traditionally carried out in aqueous buffer at pH 7.5-8. However, the aqueous rout exhibits several drawbacks in enzyme stability and product recovery. In this study, several ionic liquids (ILs) have been used as media for enzymatic hydrolysis of penicillin G. The results indicated that hydrophobic ILs/water two-phase system were good media for the reaction. In addition, a novel aqueous two-phase system based on the lower critical solution temperature type phase changes of amino acid based ILs/water mixture was developed for in situ penicillin G hydrolysis and product separation. For instance, hydrolysis yield of 87.13% was obtained in system containing 30 wt% [TBP][Tf-ILe] with pH control (pH 7.6). Since the phase-separation of this medium system can be reversible switched from single to two phases by slightly changing the solution temperature, enzymatic hydrolytic reaction and product recovery were more efficient than those of aqueous system. In addition, the ILs could be reused for at least 5 cycles without significant loss in hydrolysis efficiency.

  1. FATE OF REVERSE OSMOSIS (RO) MEMBRANES DURING OXIDATION BY DISINFECTANTS USED IN WATER TREATMENT: IMPACT ON MEMBRANE STRUCTURE AND PERFORMANCES

    KAUST Repository

    Maugin, Thomas

    2013-12-01

    Providing pretreatment prior RO filtration is essential to avoid biofouling and subsequent loss of membrane performances. Chlorine is known to degrade polymeric membrane, improving or reducing membrane efficiency depending on oxidation conditions. This study aimed to assess the impact of alternative disinfectant, NH2Cl, as well as secondary oxidants formed during chloramination of seawater, e.g. HOBr, HOI, or used in water treatment e.g. ClO2, O3, on membrane structure and performances. Permeability, total and specific rejection (Cl-, SO4 2-, Br-, Boron), FTIR profile, elemental composition were analyzed. Results showed that each oxidant seems to react differently with the membrane. HOCl, HOBr, ClO2 and O3 improved membrane permeability but decreased rejection in different extent. In comparison, chloramines resulted in identical trends but oxidized membrane very slowly. On the contrary, iodine improved membrane rejection e.g. boron, but decreased permeability. Reaction conducted with chlorine, bromine, iodine and chloramines resulted in the incorporation of halogen in the membrane structure. All oxidant except iodine were able to break amide bonds of the membrane structure in our condition. In addition, chloramine seemed to react with membrane differently, involving a potential addition of nitrogen. Chloramination of seawater amplified membrane performances evolutions due to generation of bromochloramine. Moreover, chloramines reacted both with NOM and membrane during oxidation in natural seawater, leading to additional rejection drop.

  2. Combining AOT, Angstrom Exponent and PM concentration data, with PSCF model, to distinguish fine and coarse aerosol intrusions in Southern France

    Science.gov (United States)

    Dimitriou, Konstantinos; Kassomenos, Pavlos

    2016-05-01

    In this paper, a cluster analysis of backward air mass trajectories, arriving in Avignon (Southern France), was combined with a Potential Source Contribution Function (PSCF) model on a 0.5° × 0.5° resolution grid, in order to indicate possible aerosol intrusions. A strict triple criterion was constructed from Aerosol Optical Thickness (AOT), Angstrom Exponent (AE), and PM (PM10 and PM2.5) concentration measurements, aiming to distinguish more effectively Episodes of Fine, Coarse and Overall Aerosols (FAE, CAE and OAE respectively). Large fractions of FAE (60.0%) and CAE (40.6%) were strongly attributed to the prevalence of Eastern and South-Southwest (S-SW) airflows respectively, whereas these distinct trajectory clusters also gathered large fractions of OAE (90.2% cumulatively). According to PSCF results, FAE events were strongly associated with the influence of air masses traveling over North Italy and Southern Germany, hence the impact of urban and industrial combustion was emerged. Main sources of coarse aerosols were principally isolated over the Mediterranean, thus the import of sea spray and dust from the Sahara desert is presumed. Satellite AOT observations were used for a more detailed identification of an intense 5-day intrusion of coarse aerosols. Short range slow moving air mass trajectories, were proven to be a clear marker of atmospheric stagnation, based on a wind speed analysis, triggering the accumulation of locally emitted anthropogenic aerosols (mainly PM2.5) and lack of city ventilation.

  3. Application of Multivariate Calibration Techniques to Simultaneous Spectrophotometric Determination of Copper and Iron Using 1-(2-Pyridylazo)-2-naphthol in AOT Micellar Solution

    Institute of Scientific and Technical Information of China (English)

    KARIM-NEZHAD Ghasem; SAGHATFOROUSH Lotfali; ERSHAD Sohrab; BAHRAMI Kokab

    2008-01-01

    Multivariate calibration models(PCR and PLS)were developed for simultaneous determination of Fe(Ⅲand Cu(Ⅱ)with 1-(2-pyridylazo)-2-naphthol and AOT as chromogenic reagent and micellizing agent,respectively.In the presence of AOT the spectrum of Fe(Ⅲ)-PAN complex was shifted to higher wavelength and the overlapping with Cu-PAN spectrum decreased.It seems that this anionic surfactant enters the structure of the Fe-PAN complex to cause a shift in the absorption spectrum of it.The parameters controlling behavior of the systems were investigated and optimum conditions were selected.Sixteen ternary mixtures were selected as the calibration set.To select the number of factors in PCR and PLS algorithms,a cross validation method,leaving out one sample at a time,was employed.The calibration models were validated with 8 synthetic mixtures containing the metal ions in different proportions that were randomly designed.The best calibration model was obtained by using PLS regression.The method was successfully applied to simultaneous determination of copper and iron in biological samples.

  4. Reversible and Irreversible Adsorption Energetics of Poly(ethylene glycol) and Sorbitan Poly(ethoxylate) at a Water/Alkane Interface.

    Science.gov (United States)

    Huston, Kyle J; Larson, Ronald G

    2015-07-14

    We simulate poly(ethylene glycol) (PEG) oligomers and model Tween 80 (polyoxyethylene sorbitan monooleate) molecules at water/alkane interfaces. Using the weighted histogram analysis method (WHAM), including an extension of WHAM to two reaction coordinates to remove hysteresis, we calculate interfacial potentials of mean force (PMFs) for PEG and Tween 80 using three force fields: the atomistic GROMOS 53a6OXY+D and two coarse-grained (CG) MARTINI force fields. Because the force fields have not yet been validated for PEO adsorption to hydrophobic interfaces, we calculate PMFs for alcohol ethoxylates C12E2 and C12E8 and find that they agree with semiempirical results of Mulqueen and Blankschtein [Langmuir 2002, 18 (2), 365-376] for the GROMOS 53a6OXY+D force field, whereas for both MARTINI force fields, PEO adsorbs too weakly to a clean hydrophobic interface. One MARTINI force field incorrectly shows depletion rather than adsorption to a clean hydrophobic interface. We find that the adsorption free energy for PEG oligomers at a clean, planar water/alkane interface is around 1.3 kBT per monomer for the atomistic force field but is less than half of this for the two CG force fields. With the newly validated GROMOS 53a6OXY+D force field, we bracket the dilute adsorption free energy for a model Tween 80 molecule at the clean water/squalane interface. We also calculate the pressure-area isotherm. We exploit these data with the Nikas-Mulqueen-Blankschtein (NMB) theory and a simple transport model to demonstrate a transition from irreversible to reversible adsorption with increasing surface coverage, consistent with experimental results of Reichert and Walker [Langmuir 2013, 29 (6), 1857-1867].

  5. Preliminary design of seawater and brackish water reverse osmosis desalination systems driven by low-temperature solar organic Rankine cycles (ORC)

    Energy Technology Data Exchange (ETDEWEB)

    Delgado-Torres, Agustin M. [Dpto. Fisica Fundamental y Experimental, Electronica y Sistemas, Escuela Tecnica Superior de Ingenieria Civil e Industrial, Universidad de La Laguna (ULL), Avda. Astrofisico Francisco Sanchez s/n. 38206 La Laguna (Tenerife) (Spain); Garcia-Rodriguez, Lourdes [Dpto. Ingenieria Energetica, Universidad de Sevilla Escuela Tecnica Superior de Ingenieros, Camino de los Descubrimientos, s/n 41092 Sevilla (Spain)

    2010-12-15

    In this paper, the coupling between the low-temperature solar organic Rankine cycle (ORC) and seawater and brackish water reverse osmosis desalination units has been carried out. Four substances have been considered as working fluids of the solar cycle (butane, isopentane, R245fa and R245ca). With these four fluids the volumetric flow of fresh water produced per unit of aperture area of stationary solar collector has been calculated. The former has been made with the optimized direct vapour generation (DVG) configuration and heat transfer fluid (HTF) configuration of the solar ORC. In the first one (DVG), working fluid of the ORC is directly heated inside the absorber of the solar collector. In the second one (HTF), a fluid different than the working fluid of the ORC (water in this paper) is heated without phase change inside the absorber of the solar collector. Once this fluid has been heated it is carried towards a heat exchanger where it is cooled. Thermal energy delivered in this cooling process is transferred to the working fluid of the ORC. Influence of condensation temperature of the ORC and regeneration's process effectiveness over productivity of the system has also been analysed. Finally, parameters of several preliminary designs of the low-temperature solar thermal driven RO desalination are supplied. R245fa is chosen as working fluid of the ORC in these preliminary designs. The information of the proposed preliminary designs can also be used, i.e., for the assessment of the use of thermal energy rejected by the solar cycle. Overall analysis of the efficiency of the solar thermal driven RO desalination technology is given with the results presented in this paper and the results obtained with the medium temperature solar thermal RO desalination system presented by the authors in previous papers. This work has been carried out within the framework of the OSMOSOL and POWERSOL projects. (author)

  6. TiO2-Based Advanced Oxidation Nanotechnologies For Water Purification And Reuse

    Science.gov (United States)

    TiO2 photocatalysis, one of the UV-based advanced oxidation technologies (AOTs) and nanotechnologies (AONs), has attracted great attention for the development of efficient water treatment and purification systems due to the effectiveness of TiO2 to generate ...

  7. Linear modeling of the soil-water partition coefficient normalized to organic carbon content by reversed-phase thin-layer chromatography.

    Science.gov (United States)

    Andrić, Filip; Šegan, Sandra; Dramićanin, Aleksandra; Majstorović, Helena; Milojković-Opsenica, Dušanka

    2016-08-01

    Soil-water partition coefficient normalized to the organic carbon content (KOC) is one of the crucial properties influencing the fate of organic compounds in the environment. Chromatographic methods are well established alternative for direct sorption techniques used for KOC determination. The present work proposes reversed-phase thin-layer chromatography (RP-TLC) as a simpler, yet equally accurate method as officially recommended HPLC technique. Several TLC systems were studied including octadecyl-(RP18) and cyano-(CN) modified silica layers in combination with methanol-water and acetonitrile-water mixtures as mobile phases. In total 50 compounds of different molecular shape, size, and various ability to establish specific interactions were selected (phenols, beznodiazepines, triazine herbicides, and polyaromatic hydrocarbons). Calibration set of 29 compounds with known logKOC values determined by sorption experiments was used to build simple univariate calibrations, Principal Component Regression (PCR) and Partial Least Squares (PLS) models between logKOC and TLC retention parameters. Models exhibit good statistical performance, indicating that CN-layers contribute better to logKOC modeling than RP18-silica. The most promising TLC methods, officially recommended HPLC method, and four in silico estimation approaches have been compared by non-parametric Sum of Ranking Differences approach (SRD). The best estimations of logKOC values were achieved by simple univariate calibration of TLC retention data involving CN-silica layers and moderate content of methanol (40-50%v/v). They were ranked far well compared to the officially recommended HPLC method which was ranked in the middle. The worst estimates have been obtained from in silico computations based on octanol-water partition coefficient. Linear Solvation Energy Relationship study revealed that increased polarity of CN-layers over RP18 in combination with methanol-water mixtures is the key to better modeling of

  8. Reversible Statistics

    DEFF Research Database (Denmark)

    Tryggestad, Kjell

    2004-01-01

    The study aims is to describe how the inclusion and exclusion of materials and calculative devices construct the boundaries and distinctions between statistical facts and artifacts in economics. My methodological approach is inspired by John Graunt's (1667) Political arithmetic and more recent work...... within constructivism and the field of Science and Technology Studies (STS). The result of this approach is here termed reversible statistics, reconstructing the findings of a statistical study within economics in three different ways. It is argued that all three accounts are quite normal, albeit...... in different ways. The presence and absence of diverse materials, both natural and political, is what distinguishes them from each other. Arguments are presented for a more symmetric relation between the scientific statistical text and the reader. I will argue that a more symmetric relation can be achieved...

  9. Performance Comparison of Two Newly Developed Bimetallic (X-Mo/Al2O3, X=Fe or Co) Catalysts for Reverse Water Gas Shift Reaction

    Institute of Scientific and Technical Information of China (English)

    Abolfazl Gharibi Kharaji; Ahmad Shariati

    2016-01-01

    The performance of the two newly developed bimetallic catalysts based on the precursor, Mo/Al2O3, was com-pared for reverse water gas shift (RWGS) reaction. The structures of the precursor and the catalysts were studied using X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) analysis, inductively coupled plasma-atomic emission spec-trometry (ICP-AES), CO chemisorption, temperature programmed reduction of hydrogen (H2-TPR) and scanning electron microscopy (SEM) techniques. The activity of Fe-Mo and Co-Mo catalysts was compared in a ifxed bed reactor at different temperatures. It is shown that the Co-Mo catalyst has higher CO2 conversion at all temperature level. The time-on-stream (TOS) analysis of the activity of catalysts for the RWGS reaction was carried out over a continuous period of 60 h for both catalysts. The Fe-Mo/Al2O3 catalyst exhibits good stability within a period of 60 h, however, the Co-Mo/Al2O3 is gradually deactivated after 50 h of reaction time. Existence of Fe2(MoO4)3 phase in Fe-Mo/Al2O3 catalyst makes this catalyst more stable for RWGS reaction.

  10. Reversible ion exchange and structural stability of garnet-type Nb-doped Li7La3Zr2O12 in water for applications in lithium batteries

    Science.gov (United States)

    Liu, Cai; Rui, Kun; Shen, Chen; Badding, Michael E.; Zhang, Gaoxiao; Wen, Zhaoyin

    2015-05-01

    H+/Li+ ion exchange and structural stability of the high ionic conductivity Nb-doped Zr-garnet Li6.75La3Nb0.25Zr1.75O12 (LLNZO) are investigated in this study. Relationships between ion exchange and Li-population per unit cell, which are necessary to establish the practical framework of garnet electrolytes, are deduced for garnet oxides within ion-exchange process. H+/Li+ ion exchange of cubic LLNZO powder is performed continuously in distilled water and products with various exchange levels are obtained via this simple method. FTIR spectra show the evolution of H-O bonding through the ion-exchange process. A maximum of 74.8% exchange of Li+ by H+ was found, consistent with a preferential replacement of octahedrally coordinated Li. The cubic garnet phase is maintained throughout all levels of proton exchange observed. The formation of garnet-type solid solution of Li6.75-xHxLa3Nb0.25Zr1.75O12 is indicated by well-resolved lattice fringes as well as the linear evolution of crystal lattice parameters with the ion exchange level. The reverse ion exchange of H+ by Li+ is successfully achieved in Li+ containing aqueous solutions, demonstrating its high structural stability and good compatibility for promising applications in lithium batteries.

  11. Process of forming compounds using reverse micelle or reverse microemulsion systems

    Science.gov (United States)

    Linehan, John C.; Fulton, John L.; Bean, Roger M.

    1998-01-01

    The present invention is directed to a process for producing a nanometer-sized metal compound. The process comprises forming a reverse micelle or reverse microemulsion system comprising a polar fluid in a non-polar or low-polarity fluid. A first reactant comprising a multi-component, water-soluble metal compound is introduced into the polar fluid in a non-polar or low-polarity fluid. This first reactant can be introduced into the reverse micelle or reverse microemulsion system during formation thereof or subsequent to the formation of the reverse micelle or microemulsion system. The water-soluble metal compound is then reacted in the reverse micelle or reverse microemulsion system to form the nanometer-sized metal compound. The nanometer-sized metal compound is then precipitated from the reverse micelle or reverse microemulsion system.

  12. Non-chemical water purification a Westinghouse/Wallenius product for nuclear power plant needs

    International Nuclear Information System (INIS)

    Increasing demand for ecologically effective water treatment technologies has resulted in the development of several new oxidation methods. These technologies are generally labelled Advanced Oxidation Technologies (AOT) or Advanced Oxidation Processes (AOP) and currently represent the most widely recognized alternative for ecologically sound, high-tech water purification. Many years of intensive research have culminated in the innovative Wallenius-AOT technology, a patented method that is remarkable in several ways. It imitates nature's own water purification method. This means no chemical additives are needed. The technology utilizes the ability of light, together with photo-catalytic semiconductor surfaces, to produce free radicals, like nature does. These reactive radicals create an environment in which organic and inorganic substances oxidize, whereby a broad spectrum of organisms is rendered harmless more effectively than with conventional UV technology. The entire process takes just a few micro-seconds. A major advantage of the technology is that it can be adjusted according to the desired degree of purification. By altering the dynamics of the process, the purification can be designed for specific applications. In this way, AOT tackles precise problems, regardless of flow and whether the problem is chemical or biological. The product was originally introduced for ballast treatment in the shipping industry. Ballast water has created severe damages to the biology at many locations. By moving an organism from one ocean to another we have introduced a possible threat to the local ecosystem. This has been prevented by using the AOT water treatment units. During ballasting and de-ballasting, the units create radicals with the help of a catalyst and a light source. These radicals then destroy the cell membrane of microorganisms. The radicals, which never leave the unit, have a lifetime of only a few milliseconds and pose no risk to the environment or crew

  13. 倒极电去离子苦咸水淡化技术的试验研究%BRACKISH WATER DESALINATION BY ELECTRODEIONIZATION WITH POLARITY REVERSAL

    Institute of Scientific and Technical Information of China (English)

    陈维利; 王建友; 费兆辉; 樊改肖

    2012-01-01

    在常规电去离子(EDI)的浓缩室中采取与淡水室相同的树脂填充策略构成频繁倒极电去离子(EDIR)过程,以模拟苦咸水为处理对象,重点考察了阴阳树脂比例、树脂粒径、隔板厚度、树脂填充方式对EDI苦咸水淡化过程的影响.结果表明,在阴阳树脂体积比4∶6、树脂粒径0.45~0.71mm、采用隔板厚度3mm以及树脂均匀混合填充时,可获得最低的产水能耗.对于3000mg/L的进水含盐量,EDIR的脱盐率可达90%以上,耗电量1.95kWh/m3,过程运行稳定.EDIR有望成为具备较强竞争力的苦咸水淡化新技术.%In this paper, the electrodeionization process with frequent polarity reversal (EDIR) process, using the same resin filling strategy both in the dilute and concentrate compartments, was carried out for brackish water desalination. With the feed of simulated brackish water, the influences of volume ratio of anion-cation resins, resin particle size distribution, compartment thickness and resin filling pattern on the separation performances of the EDIR were investigated. The results showed that at a resin ratio of 4:6 (anion to cation), resin particle range of 0.45 to 0.71 mm and the compartment thickness of 3 mm, the lowest power Consumption was achieved when the even mixing pattern of resin filling was adopted. When the feed TDS was 3 000 mg/L, the EDIR can give a salt rejection of 90% while the power consumption was 1.95 kWh/m3 with good stability. The EDIR was hopeful to be a new choice for brackish water desalination with potential superiorities.

  14. Synthesis of nanosilver particles by reverse micelle method and study of their bactericidal properties

    Energy Technology Data Exchange (ETDEWEB)

    Tran Thi Ngoc Dung; Ngo Quoc Buu; Dang Viet Quang; Le Anh Bang; Nguyen Hoai Chau; Nguyen Thi Ly [Institute of Environmental Technology, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Road, Cau Giay Distr., Hanoi (Viet Nam); Huynh Thi Ha [Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Road, Cau Giay Distr., Hanoi (Viet Nam); Nguyen Vu Trung [National Institute for Infectious and Tropical Diseases, 1 Ton That Tung, Dong Da Distr., Hanoi (Viet Nam)], E-mail: ttndzung@yahoo.com, E-mail: buu_nq@yahoo.com

    2009-09-01

    Nanosilver particles have been synthesized by the reverse micelle method, where AgNO{sub 3} was used as a silver ions source, NaBH{sub 4} and quercetin - as reducing agents, CTAB, SDOSS and AOT- as surfactants, while the stabilizer was Vietnamese chitosan. Studying the factors influencing the process of nanosilver particle formation, it was shown that the particle size of the nanosilver products depends on the concentration of the reaction components and their stoichiometric ratio. It was also shown that the reaction system using AOT surfactant is capable of producing nanosilver particles with smallest nanoparticles ({phi}{sub av} {approx} 5 nm) and good particle-size distribution. The study on bactericidal activity of the nanosilver products indicated that the disinfecting solution with a nanosilver concentration of 3 ppm was able to inhibit all E.coli and Coliforms, TPC and fungi at 15 ppm, while Vibrio cholerae cells were inactivated completely with 0.5 ppm of nanosilver after 30 minutes exposition.

  15. Reverse Osmosis Optimization

    Energy Technology Data Exchange (ETDEWEB)

    McMordie Stoughton, Kate; Duan, Xiaoli; Wendel, Emily M.

    2013-08-26

    This technology evaluation was prepared by Pacific Northwest National Laboratory on behalf of the U.S. Department of Energy’s Federal Energy Management Program (FEMP). ¬The technology evaluation assesses techniques for optimizing reverse osmosis (RO) systems to increase RO system performance and water efficiency. This evaluation provides a general description of RO systems, the influence of RO systems on water use, and key areas where RO systems can be optimized to reduce water and energy consumption. The evaluation is intended to help facility managers at Federal sites understand the basic concepts of the RO process and system optimization options, enabling them to make informed decisions during the system design process for either new projects or recommissioning of existing equipment. This evaluation is focused on commercial-sized RO systems generally treating more than 80 gallons per hour.¬

  16. Reverse Osmosis Optimization

    Energy Technology Data Exchange (ETDEWEB)

    None

    2013-08-01

    This technology evaluation was prepared by Pacific Northwest National Laboratory on behalf of the U.S. Department of Energy’s Federal Energy Management Program (FEMP). The technology evaluation assesses techniques for optimizing reverse osmosis (RO) systems to increase RO system performance and water efficiency. This evaluation provides a general description of RO systems, the influence of RO systems on water use, and key areas where RO systems can be optimized to reduce water and energy consumption. The evaluation is intended to help facility managers at Federal sites understand the basic concepts of the RO process and system optimization options, enabling them to make informed decisions during the system design process for either new projects or recommissioning of existing equipment. This evaluation is focused on commercial-sized RO systems generally treating more than 80 gallons per hour.

  17. Theoretical studies on the catalysis of the reverse water-gas shift reaction using first-row transition metal beta-diketiminato complexes.

    Science.gov (United States)

    Liu, Cong; Munjanja, Lloyd; Cundari, Thomas R; Wilson, Angela K

    2010-06-01

    The reverse water-gas shift reaction CO(2) + H(2) --> H(2)O + CO has been investigated using a set of homogeneous catalyst models L'M(I) (L' = beta-diketiminate, C(3)N(2)H(5)(-); M = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn). The thermodynamics of prototypical reaction pathways were simulated at two levels of theory: B3LYP/6-311+G(d) and B3LYP/aug-cc-pVTZ. The modeled catalytic reaction has been considered in the following steps: coordination of CO(2) by the catalyst to generate a carbon dioxide complex, L'M(CO(2)); scission of L'M(CO(2)) to yield L'M(CO) and L'M(O); L'M(O) hydrogenation to form L'M(H(2)O). The final products, H(2)O and CO, were obtained from the dissociation of L'M(H(2)O) and L'M(CO). All of the reactants, intermediates, and products were modeled, where different possible conformers and multiplicities were identified and considered as potential minima. The reaction enthalpy DeltaH, of all steps for each catalyst as a function of transition metal have been determined. The Mn and Fe catalysts show more thermodynamically accessible pathways than the other catalyst models studied. The overall reaction enthalpy has been determined not only by B3LYP/6-311+G(d) and B3LYP/aug-cc-pVTZ but also via a more rigorous ab initio electron-correlation-based approach, the correlation consistent Composite Approach (ccCA). PMID:20462216

  18. Determination of Methanol Increment in Mobile Phase Consisting of Methanol and Water by On-line UV Spectrometry in Reversed Phase Liquid Chromatography

    Institute of Scientific and Technical Information of China (English)

    GENG,Xin-Du(耿信笃); REGNIER,Fred E(弗莱德 依 瑞格涅尔)

    2002-01-01

    An on-line UV spectrometric method for the quantitative determination of methanol increment of methanol-water in the mobile phase(i.e., ofgreater concentration than that of the mobile phase ) by frontal analysis (FA) of insulin in reversed phase liquid chromatography (RPLC) was presented. When the methanol increment concentration ranged from 0.05% to 0.50%, V( CH3OH)/ V(H2O), a set of elution curves could be obtained at 198 nm by a diode-array detector in the presence of 47% methanol, V(CH3OH)/V(H2O) containing 0.03% hydrochloric acid, V ( CH3OH-H2O ) / V ( HCl ) in the mobile phase. The plateau height of the elution curves of the methanol increment was found to be proportional to the methanol increment in the mobile phase. The methanol increment could be determined on a quantitative basis. When the method was used to investigate the elution curve of insulin by FA in RPLC, a small plateau, being the methanol increment,was detected before the usual insulin plateau of each elution curve. In this case the methanol increment was found to vary with insulin concentration in the mobile phase. When that concentration was between 0.025 mg/mL and 0.30 mg/mL,the methanol increment could be determined in the range from 0.03% to0.19% with a deviation of ±0.02% and a relative deviation of ± 10%. A nuclear magnetic resonance spectrometer (NMR) was also employed to confirm the obtained result. A methodology with a very rigorous experimental procedure for obtaining results of such accuracy is also included.The presented result may be used to prove that a displacement process definitely occurs as insulin is adsorbed by the RPLC stationary phase inFA.

  19. BOILER MAKE-UP WATER TREATMENT USING REVERSE OSMOSIS-MIXED BED SYSTEM%采用反渗透-混床系统进行锅炉补给水处理

    Institute of Scientific and Technical Information of China (English)

    杨文君; 何新玲

    2001-01-01

    介绍了反渗透-混床除盐系统处理锅炉补给水时的运行经验。经4年的实践表明:(1)采用机械搅拌澄清池和三级过滤的系统,可以达到反渗透组件对进水水质的要求;(2)反渗透组件的脱盐率每年约降低1%~2%,在设计中必须考虑;(3)一般情况下,反渗透装置的出水应经过除碳器再送入混床;(4)混床的出力必须有足够的余量,以免影响供水。%Operational experience of boiler make-up water treatment by using reverse osmosis-mixed bed demin-eralizing system has been described. Practice during the period of four years shows: (1) Settled water pond and three-stage filtration system with mechanical agitation can meet the requitments of reverse-osmosis components to the inlet water quality; (2) It must be considered in the design that the demineralization efficiency of reverse-osmosis components will be decreased about 1%~2% in every year; (3) In normal case, the outlet water from reverse-osmosis equipment shall enter into mixed bed via a decarbonator; (4) The output capacity of the mixed bed must have a sufficient surplus, to avoid its influence on the water supply.

  20. On softened water reverse osmosis centralized control scheme and common defect analysis%软化水反渗透系统集控方案及常见故障分析

    Institute of Scientific and Technical Information of China (English)

    张琦

    2015-01-01

    介绍了软化水反渗透系统的主要包含部分及功能,着重对该系统常见的故障进行了原因分析,主要有RO增压泵不工作、计量泵不工作、反渗透产水量下降等问题,以制定出有效的解决措施,保证系统的正常运行。%The paper introduces the main parts and functions of the softened water reverse osmosis system,analyzes reasons for common defects of the system,including the insufficiency in the RO booster pump and metering pump,and lower water yield of the reverse osmosis,so as to make the effective solutions and ensure the common operation of the system.

  1. Effect of water temperature on reverse osmosis unit and countermeasures%水温对反渗透装置运行的影响及对策措施

    Institute of Scientific and Technical Information of China (English)

    陈乾荣; 何驹; 娄伦武; 王启延

    2015-01-01

    This paper sketches obvious effects of water temperature on operation pressure, desalination rate, pressure drop and producing water capacity, it also introduces producing water capacity in winter appears linear decrease with reduction of water temperature in reverse osmosis plants, through heating reverse osmosis feedwater with steam condensate, on condition of no-adding new device and energy consumption which solves producing water capacity low in winter, guaranteed efficiently water demand for follow-up devices.%简述了进水温度对反渗透装置的运行压力、脱盐率、压降以及产水能力影响极为明显,介绍该公司反渗透装置出现了冬季产水量随着水温降低而呈现线性下降的情况,通过换热装置用蒸汽冷凝液加热反渗透进水,在不增加新装置和能耗的前提下解决了冬季产水量少的问题,有效保障了后续装置的用水需求。

  2. Application of Electric Pulse-coagulation Treatment Method in Reverse Osmosis Concentrated Water Treatment%电脉冲-混凝处理法在反渗透浓水处理中的应用

    Institute of Scientific and Technical Information of China (English)

    于玥; 邓柏杰

    2015-01-01

    文章以炼油厂反渗透浓缩水为研究对象,采用电脉冲—混凝法处理炼油厂反渗透浓水。选择聚环氧乙烷作为助凝剂,采用电脉冲—聚环氧乙烷混凝处理反渗透浓水,确定优化参数,分析和讨论实验现象和实验结果。%Taking reverse osmosis concentrated water as the research object in refinery,reverse osmosis concentrated water is treated by electric pulse-coagulation treatment in refinery.The choice of polyethylene oxide as a coagulant,the electric pulse-polyethylene oxide coagulation treatment of concentrated water reverse osmosis,determining the optimal parameter;the experimental phenomena and experimental results are analyzed and discussed in the paper.

  3. Study on preparation of D5 reverse micelle systems and their water solubilization performance%D5反胶束体系的制备及其增溶特性的研究

    Institute of Scientific and Technical Information of China (English)

    万伟; 刘今强; 李莎; 鲁凤鸣; 王际平; 张玉高

    2009-01-01

    以对生态环境友好的D5(十甲基环五硅氧烷)替代传统反胶束体系中的烷烃作为连续相介质,制备新型的D5反胶束体系,并对该体系的增溶行为进行研究,分别比较了阴离子表面活性剂、阳离子表面活性剂、非离子表面活性剂的D5反胶束体系的增溶水量.结果表明,用非极性的D5替代传统反胶束体系中的烷烃来制备对生态环境友好的反胶束体系的方法可行;在某些需要助表面活性剂才能形成的D5反胶束体系里,助表面活性剂醇的用量和表面活性剂的类型及其浓度都影响着体系的增溶水量;非离子表面活性剂形成的TX-10/正辛醇/D5反胶束体系增溶水量最大.%The novel D5 reverse micelle systems have been prepared by substituting the eco-friendly D5 (decamethyl cyclopentasiloxane) for the alkanes of traditional reverse micelle systems as continuous phase medium, and the water solubilization behaviors of the systems have been investigated by comparing the water solubilization amount of D5 reverse micelle systems prepared with anionic surfactant, cau'onic surfactant and non-ionic surfactant respectively. The results show that it is a feasible way to substitute the non-polar D5 for the traditional alkanes for preparing reverse micelle systems, and it is much more eco-friendly ; in the cases of that cosurfactants are necessary for preparing reverse micelle systems, both the dosage of the alcohol as cosurfactant and the type and the concentration of the surfactant affect the water solubilization amount;the TX-10/n-octanol/D5 reverse micelle system formed from non-ionic surfactant has the maximum water solubilization amount.

  4. OP-7/氯仿反胶束体系的制备及其增溶水量的研究%Study on preparation of OP-7/chloroform reverse micelle systems and their water solubilization performance

    Institute of Scientific and Technical Information of China (English)

    赵群; 陈怡秀; 朱青; 沈炎冰; 邓龙根; 马超; 阎克路

    2013-01-01

    The novel OP-7/chloroform reverse micelle system have been prepared by substituting chloroform for the alkanes of traditional reverse micelle systems,and the water solubilization behaviors of the systems have been investigated.The impact of OP-7' s concentration and the type of cosurfactant on the water solubilization amount of reverse micelle systems and the relationship between the water solubilization amount and the size and the conductivity of the systems were studied.The results showed that both the dosage of OP-7,the type and the concentration of the alcohol as cosufactant affect the water solubilization amount ; at the same time,the size and conductivity of the systems increased with increasing water solubilization amount,the OP-7/n-octanol/chloroform has the maximum water solubilization amount.%以氯仿代替传统的烃类溶剂,制备新型OP-7(非离子表面活性剂)/氯仿反胶束体系,并对该体系的增溶行为进行研究.考察了OP-7的浓度和不同的助表面活性剂对该体系增溶水量的影响及增溶水量与体系的粒径、电导率的关系.结果表明,OP-7的浓度、助表面活性剂醇的种类和用量都影响着体系的增溶水量;同时增溶水量增加,体系的粒径和电导率随之增加,OP-7/正辛醇/氯仿反胶束体系增溶水量最大.

  5. Renewable synthesis-gas-production. Do hydrocarbons in the reactant flow of the reverse water-gas shift reaction cause coke formation?

    Energy Technology Data Exchange (ETDEWEB)

    Wolf, A.; Kern, C.; Jess, A. [Bayreuth Univ. (Germany). Dept. of Chemical Engineering

    2013-11-01

    In a two-step synthetic fuel production process based on carbon dioxide and renewable hydrogen, the best possible selectivity towards liquid hydrocarbons (Hc) shall be implemented. The process consists of a combination of the Reverse Water-Gas Shift reaction and the Fischer-Tropsch synthesis. To achieve this goal, gaseous short-chained Hc from the FTS reactor are recycled in the RWGS unit. In this paper, challenges coming up with the implementation of a recycle loop are discussed. First of all, it has to be examined whether Hc are converted under conditions present in the RWGS reactor. The coking caused by the recycle of Hc is regarded, including thermal coking in the heating zone of the reactor and catalytic coking in the catalyst bed. Coking of course is unwanted, as it deactivates the catalyst. The scope of this work is to find out to which extent and under which conditions gaseous Hc can be recycled. Therefore, experiments were carried out in both, a quartz glass reactor using a commercial Ni-catalyst at ambient pressure and in a pressurized steel reactor (without catalyst) to examine coking during the thermal decomposition of Hc. The catalytic experiments at atmospheric pressure showed that a recycle of CH{sub 4} did not cause coking up to a ratio of CH{sub 4}/CO{sub 2} below one. For these conditions, long term stability was proved. The reaction rates of the CH{sub 4} conversion were below those of the RWGS reaction. However, replacing CH{sub 4} by C{sub 3}H{sub 8} leads to thermal and catalytic coking. Catalytic coking hits the maximum level at about 700 C and decreases for higher temperatures and, thus is not regarded as a problem for the RWGS reactor. In contrast to that, thermal coking raises with higher temperatures, but it can be supressed efficiently with additional injection of H{sub 2}O, which of course shifts the equilibrium towards the undesired reactant side. (orig.)

  6. Water in oil microemulsions containing NaCl for transdermal delivery of fluorouracil%含电解质的W/O型微乳作为氟尿嘧啶透皮给药载体的研究

    Institute of Scientific and Technical Information of China (English)

    肖衍宇; 刘芳; 陈志鹏; 平其能

    2011-01-01

    This study is to prepare the W/O microemulsion containing NaC1 and fluorouracil (5-Fu) as a model drug to investigate the transdermal characteristics and skin irritation of the microemulsion in vitro. Isopropylmyristate (IPM) acting as oil phase, Aerosol-OT (AOT) as surfactant, Tween 85 as cosurfactant, NaC1 solution was added dropwise to the oil phase to prepare W/O microemulsion at room temperature using magnetic stirring, and then 5-Fu powder was added. According to the area of microemulsion based on the pseudo-tertiary phase diagrams, the optimum formulation was screened initially. And the permeation flux of fluorouracil across excised mice skin was determined in vitro using Franz: diffusion cells to study the influence of the amount of water and the drug loading capacity and optimize the formulation further. Refer to 5-Fu cream, the irritation of microemulsion on the rat skin was studied. The optimum formulation was composed of 0.7% (w/v) 5-Fu, 50% NaC1 solution (0.05 mol·L-1), 20% mix-surfactant (AOT/Tween 85, Km = 2) and 29.3% oil (IPM). The cumulative amount of fluorouracil permeated in 12 h was (2 013.4± 41.6) μg·cm-2, 20.23 folds and 10.38 folds more than 0.7% fluorouracil aqueous solution and 2.5% (w/w) fluorouracil cream, respectively. Microemulsion exhibited some irritation, but could be reversed after drug withdrawal. The addition of NaC1 significantly increased the content of water and the drug loading in microemulsion systems. The NaC1/AOT-Tween 85/IPM microemulsion system promoted the permeation of fluorouracil greatly, which may be a promising vehicle for the transdermal delivery of fluorouracil and other hydrophilic drug.%通过电解质氯化钠(NaCl)的加入,制备含水量高、载药量高且透过能力强的氟尿嘧啶(5-Fu)W/O型微乳,并研究其体外透皮特性及皮肤刺激性.以肉豆蔻酸异丙酯(IPM)为油相,磺化琥珀酸二辛酯钠(AOT)为表面活性剂,Tween 85为助表面活性剂,在室温下采用

  7. The Application of Reverse Osmosis Technology in QingJiang Petrochemical Demineralized Water Process%反渗透技术在清江石化除盐水工艺中的应用

    Institute of Scientific and Technical Information of China (English)

    周健; 华伦

    2012-01-01

    This paper summarizes the structure,producing area and application industry of the Dow reverse osmosis membrane membrane.The technical process,the process control parameters(recovery rate,desalination rate,in-and-out water quality) and process flow and reverse osmosis desalting operation of the reverse osmosis desalting device in Qingjiang petrochemical plant are included.The use of Dow reverse osmosis membrane element,the characteristics and the application,design principle of process,process flow,parameters,and the cleaning frequency in application are also covered.At the same time,some relevant improvement measures are proposed.%综述了陶氏反渗透膜的膜结构、产地及应用行业。阐述了清江石化反渗透脱盐装置的工艺过程、工艺控制参数(回收率、脱盐率、进出水水质)及工艺流程和反渗透脱盐装置的运行情况,包括使用的陶氏反渗透膜元件的特点及应用,设计的工艺原理、流程、参数,以及应用中存在的清洗周期短、制水比居高不下等问题及相关改进措施。

  8. Application of Reverse Osmosis Technology on Treatment of Saline Condensate Water%反渗透技术在含盐冷凝水处理中的应用

    Institute of Scientific and Technical Information of China (English)

    陈留平; 张云云

    2012-01-01

    文章根据国内制盐行业的水资源使用现状,结合国内典型的真空制盐装置,介绍了反渗透技术改造电站传统制水装置后处理含盐冷凝水方案,并对其经济性作了分析,展示了反渗透技术处理含盐冷凝水的环保价值和经济价值,以及在制盐行业的应用前景.%According to the status of water resource utilization in civil salt industry and combining with typical vacuum salt production equipment, the treatment solution to saline condensate water discharged from traditional water preparation system in power station is introduced by reverse osmosis technology. The economy is also analyzed. It is shown that there will be environmental protection value, economic value and application prospects in salt industry if the reverse osmosis technology is used to treat saline condensate water.

  9. Removal of Mutagenic Organic Pollutants from Drinking Water by Combined Reverse Osmosis%反渗透组合工艺去除水中致突变有机物

    Institute of Scientific and Technical Information of China (English)

    张绍园; 姜兆春; 贾智萍; 李予江

    2001-01-01

    Using CODMn and Ames test as evaluation index,the reverse osmosisbase d process for drinking water treatment was studied on removal of mutagenic organ ic pollutants from tap water.The study results show that the activated carbon un it in the process can remove about 50% of organic pollutants,but the attenuation of tap water mutagenicity is poor.The reverse osmosis unit can remove organic p ollutants and attenuate mutagenicity simultaneously.This combined process is fea sible for providing safe potable water with good quality.%以高锰酸盐指数(CODMn)和Ames试验为评价指标,研究了以反渗透为主的组合工艺对自来水中致突变性有机物的去除效果。试验表明,组合工艺中的活性炭单元可以去除自来水中约50%的有机污染物,但对自来水的致突变性没有明显改善;反渗透膜单元能达到同时去除有机污染物和改善自来水致突变性的效果。此工艺是获得安全优质饮用水的一种可行办法。

  10. Reversible arithmetic logic unit

    OpenAIRE

    zhou, Rigui; Shi, Yang; Zhang, Manqun

    2011-01-01

    Quantum computer requires quantum arithmetic. The sophisticated design of a reversible arithmetic logic unit (reversible ALU) for quantum arithmetic has been investigated in this letter. We provide explicit construction of reversible ALU effecting basic arithmetic operations. By provided the corresponding control unit, the proposed reversible ALU can combine the classical arithmetic and logic operation in a reversible integrated system. This letter provides actual evidence to prove the possib...

  11. Waste water treatment by means of chamber filtration and reverse osmosis - an economic alternative for centrifuges and evaporators; Abwasserbehandlung mittels Kammerfiltration und Reverse Osmose - eine wirtschaftliche Alternative zu Zentrifuge und Verdampfer

    Energy Technology Data Exchange (ETDEWEB)

    Marr, E. [Hansa Projekt Anlagentechnik GmbH, Moerfelden (Germany); Anderssohn, H. [Hansa Projekt Anlagentechnik GmbH, Hamburg (Germany)

    2003-07-01

    Pre-coated filters and boiling water systems were used up to now for the treatment of the washing and sump water arising in the controlled area of nuclear power plants. In order to optimize the operation of the vaporiser systems and arrange them free of interference, centrifugal systems were connected in series for separating undissolved solids. Indrum drying plants are used for further processing of the evaporator sludge right through to a salt block. As the type of problem in the waste water sector has been subject to a change over the last few years, on the one hand no new power plants are being built in Germany and the demands are coming out of the decommissioning of the plants, while on the other a trend away from vaporiser systems towards filtration systems can be observed abroad and here especially in the USA. As HPA has been operating very strongly on the Korean market for several years and the same change is apparent here as in the USA, we have developed adequate systems for application in nuclear plants. (orig.)

  12. Process optimization for reverse micellar extraction of stem bromelain with a focus on back extraction.

    Science.gov (United States)

    Dhaneshwar, Amrut D; Chaurasiya, Ram Saran; Hebbar, H Umesh

    2014-01-01

    In the current study, reverse micellar extraction (RME) for the purification of stem bromelain was successfully achieved using the sodium bis(2-ethylhexyl) sulfosuccinate (AOT)/isooctane system. A maximum forward extraction efficiency of 58.0% was obtained at 100 mM AOT concentration, aqueous phase pH of 8.0 and 0.2 M NaCl. Back extraction studies on altering stripping phase pH and KCl concentration, addition of counter-ion and iso-propyl alcohol (IPA) and mechanical agitation with glass beads indicated that IPA addition and agitation with glass beads have significant effects on extraction efficiency. The protein extraction was higher (51.9%) in case of the IPA (10% v/v) added system during back extraction as compared to a cetyltrimethylammonium bromide (100 mM) added system (9.42%). The central composite design technique was used to optimize the back extraction conditions further. Concentration of IPA, amount of glass beads, mixing time, and agitation speed (in rpm) were the variables selected. IPA concentration of 8.5% (v/v), glass bead concentration of 0.6 (w/v), and mixing time of 45 min at 400 rpm resulted in higher back extraction efficiency of 45.6% and activity recovery of 88.8% with purification of 3.04-fold. The study indicated that mechanical agitation using glass beads could be used for destabilizing the reverse micelles and release of bromelain back into the fresh aqueous phase. PMID:24616421

  13. Managing Reverse Logistics or Reversing Logistics Management?

    NARCIS (Netherlands)

    M.P. de Brito (Marisa)

    2004-01-01

    textabstractIn the past, supply chains were busy fine-tuning the logistics from raw material to the end customer. Today an increasing flow of products is going back in the chain. Thus, companies have to manage reverse logistics as well.This thesis contributes to a better understanding of reverse log

  14. Reverse osmosis application studies

    International Nuclear Information System (INIS)

    To assess the feasibility of applying reverse osmosis (RO) and ultrafiltration (UF) for effective treatment of process and waste streams from operations at Ontario Hydro's thermal and nuclear stations, an extensive literature survey has been carried out. It is concluded that RO is not at present economic for pretreatment of Great Lakes water prior to ion exchange demineralization for boiler makeup. Using both conventional and novel commercial membrane modules, RO pilot studies are recommended for treatment of boiler cleaning wastes, fly ash leachates, and flue gas desulphurization scrubber discharges for removal of heavy metals. Volume reduction and decontamination of nuclear station low-level active liquid waste streams by RO/UF also appear promising. Research programmes are proposed

  15. Operation of waste water recycling system in reverse osmosis and ultra-filtration and its improvement%超滤反渗透污水回用系统的运行及改进

    Institute of Scientific and Technical Information of China (English)

    孙柏岩; 李晓巍; 孔剑锋; 隗华

    2012-01-01

      After four years operation of the water recycling system with ultra filtration and reverse osmosis in Gold East Paper, scale formation and dirt blockage occurred in reverse osmosis because of higher alkalinity, conductivity and water hardness. The composite membrane treatment project was adopted to reduce the running cost and fresh water consumption, eliminate the hidden danger.%  金东纸业超滤(UF)和反渗透(RO)污水处理回用系统在运行约四年后,由于反渗透进水水质存在波动,碱度、电导率和硬度常常偏高,导致反渗透系统非常容易结垢和污堵。采用综合膜处理方案,结合应用3D TRASAR膜自动化技术后,污水回用系统总运行费用(TCO)明显下降,减少了清水用量,从根本上消除了系统运行的隐患。

  16. Reversible Thermoset Adhesives

    Science.gov (United States)

    Mac Murray, Benjamin C. (Inventor); Tong, Tat H. (Inventor); Hreha, Richard D. (Inventor)

    2016-01-01

    Embodiments of a reversible thermoset adhesive formed by incorporating thermally-reversible cross-linking units and a method for making the reversible thermoset adhesive are provided. One approach to formulating reversible thermoset adhesives includes incorporating dienes, such as furans, and dienophiles, such as maleimides, into a polymer network as reversible covalent cross-links using Diels Alder cross-link formation between the diene and dienophile. The chemical components may be selected based on their compatibility with adhesive chemistry as well as their ability to undergo controlled, reversible cross-linking chemistry.

  17. Comparison of Aerosol Optical Properties and Water Vapor Among Ground and Airborne Lidars and Sun Photometers During TARFOX

    Science.gov (United States)

    Ferrare, R.; Ismail, S.; Browell, E.; Brackett, V.; Clayton, M.; Kooi, S.; Melfi, S. H.; Whiteman, D.; Schwemmer, G.; Evans, K.

    2000-01-01

    We compare aerosol optical thickness (AOT) and precipitable water vapor (PWV) measurements derived from ground and airborne lidars and sun photometers during the Tropospheric Aerosol Radiative Forcing Observational Experiment. Such comparisons are important to verify the consistency between various remote sensing measurements before employing them in any assessment of the impact of aerosols on the global radiation balance. Total scattering ratio and extinction profiles measured by the ground-based NASA Goddard Space Flight Center scanning Raman lidar system, which operated from Wallops Island, Virginia (37.86 deg N, 75.51 deg W); are compared with those measured by the Lidar Atmospheric Sensing Experiment (LASE) airborne lidar system aboard the NASA ER-2 aircraft. Bias and root-mean-square differences indicate that these measurements generally agreed within about 10%. Aerosol extinction profiles and estimates of AOT are derived from both lidar measurements using a value for the aerosol extinction/backscattering ratio S(sub a) = 60 sr for the aerosol extinction/backscattering ratio, which was determined from the Raman lidar measurements. The lidar measurements of AOT are found to be generally within 25% of the AOT measured by the NASA Ames Airborne Tracking Sun Photometer (AATS-6). However, during certain periods the lidar and Sun photometer measurements of AOT differed significantly, possibly because of variations in the aerosol physical characteristics (e.g., size, composition) which affect S(sub a). Estimates of PWV, derived from water vapor mixing ratio profiles measured by LASE, are within 5-10% of PWV derived from the airborne Sun photometer. Aerosol extinction profiles measured by both lidars show that aerosols were generally concentrated in the lowest 2-3 km.

  18. Reverse Shoulder Arthroplasty

    Medline Plus

    Full Text Available ... you can use for reverse shoulder replacement. The standard delto-pectoral approach, or the superior approach, which ... that are different between a reverse and a standard total is, first of all, we don't ...

  19. Reverse cholesterol transport revisited

    Institute of Scientific and Technical Information of China (English)

    Astrid; E; van; der; Velde

    2010-01-01

    Reverse cholesterol transport was originally described as the high-density lipoprotein-mediated cholesterol flux from the periphery via the hepatobiliary tract to the intestinal lumen, leading to fecal excretion. Since the introduction of reverse cholesterol transport in the 1970s, this pathway has been intensively investigated. In this topic highlight, the classical reverse cholesterol transport concepts are discussed and the subject reverse cholesterol transport is revisited.

  20. Reverse logistics - a framework

    NARCIS (Netherlands)

    M.P. de Brito (Marisa); R. Dekker (Rommert)

    2002-01-01

    textabstractIn this paper we define and compare Reverse Logistics definitions. We start by giving an understanding framework of Reverse Logistics: the why-what-how. By this means, we put in context the driving forces for Reverse Logistics, a typology of return reasons, a classification of product

  1. Clean energy generation using capacitive electrodes in reverse electrodialysis

    NARCIS (Netherlands)

    Vermaas, D.A.; Bajracharya, S.; Bastos Sales, B.; Saakes, Michel; Hamelers, B.; Nijmeijer, D.C.

    2013-01-01

    Capacitive reverse electrodialysis (CRED) is a newly proposed technology to generate electricity from mixing of salt water and fresh water (salinity gradient energy) by using a membrane pile as in reverse electrodialysis (RED) and capacitive electrodes. The salinity difference between salt water and

  2. 同程布置冷水系统管网水力特性计算机分析%Computer calculation method of hydraulic characteristics of reversed return chilled water system

    Institute of Scientific and Technical Information of China (English)

    刘雪峰; 刘金平; 陈星龙; 陆继东

    2012-01-01

    以同程布置的冷水系统管网为研究对象,在充分考虑末端支路温度调节阀调节特性的基础上,建立了管网水力计算数学模型,提出了虚拟流量的计算机逻辑算法.以10个AHU支路的同程式管网为例,在所有末端支路水力可调、部分AHU关闭及部分AHU调节失灵3种情况下,分别计算了不同供回水压差下各支路温度调节阀的开度和实际流量,计算结果符合同程式管网的固有特性.%Taking a reverse-return chilled water system as the research object, based on full consideration of the regulating characteristics of temperature regulating valves in terminal branches, establishes a mathematical model of pipe network hydraulic characteristics, and puts forward a computer logic algorithm with virtual flow. Taking a reverse-return pipe network with ten AHU branches as the example, calculates the opening of temperature regulating valves and actual flow in branches respectively in the condition of different supply-return water pressure differences in three kinds of operating conditions of pipe network including all terminal branches being hydraulic adjustable, part AHU closing and part AHU being out of adjustment. The calculation results are in accord with the natural characteristics of reversed return pipe network.

  3. Physic-Chemical treatment and demineralization by EDR to reutilize the effluent of an urban waste water treatment plant; Tratamiento fisico-quimico y desmineralizacion por electrodialisis reversible para reutilizar el efluente de una EDAR urbana

    Energy Technology Data Exchange (ETDEWEB)

    Torres Corral, M.; Pino, M.P. del; Gil Lodos, M.; Rodriguez Garcia, M.

    1998-12-01

    Etudes held at the research and development center DEREA placed at Gran Canaria, Canary islands, have proved the viability of regenerating urban waste waters treating the effluent of an urban waste water treatment plant (WWTP del surest) with a physic-chemical treatment followed by a demineralization by electrodialysis reversal. The physic-chemical system was composed of the following units: 1 coagulation tank, 3 floculators, 1 lamellar decanter, 1 pH neutralization system, 1 chlorination system, 1 multi bed filter with chemicals reservoir, dosifiers for lime, FeCl{sub 3} polielectrolytes, sulfuric acid, and NaOCl. The physic-chemical system treated daily about 250-300 cubic meters of the effluents of the EDAR del surest, without chlorination effluent, and worked with a 90% recovery (got 90 m``3 for each 100 feeded). (Author)

  4. ENVIRONMENTAL TECHNOLOGY VERIFICATION REPORT, REMOVAL OF ARSENIC IN DRINKING WATER: WATTS PREMIER M-SERIES M-15,000 REVERSE OSMOSIS TREATMENT SYSTEM

    Science.gov (United States)

    Verification testing of the Watts Premier M-Series M-15,000 RO Treatment System was conducted over a 31-day period from April 26, 2004, through May 26, 2004. This test was conducted at the Coachella Valley Water District (CVWD) Well 7802 in Thermal, California. The source water...

  5. REMOVAL OF CHEMICAL AND MICROBIAL CONTAMINANTS IN DRINKING WATER - WATTS PREMIER M-2400 POINT-OF-ENTRY REVERSE OSMOSIS DRINKINGWATER TREATMENT SYSTEM

    Science.gov (United States)

    The Watts Premier M-2400 POE RO Drinking Water Treatment System was tested at the NSF Drinking Water Treatment Systems Laboratory for removal of the viruses fr and MS2, the bacteria Brevundimonas diminuta, and chemicals aldicarb, benzene, cadmium, carbofuran, cesium, chl...

  6. Non-Thermal Plasma (NTP) session overview: Second International Symposium on Environmental Applications of Advanced Oxidation Technologies (AOTs)

    International Nuclear Information System (INIS)

    Advanced Oxidation Technologies (used in pollution control and treating hazardous wastes) has expanded from using hydroxyl radicals to treat organic compounds in water, to using reductive free radicals as well, and to application to pollutants in both gases and aqueous media. Non-Thermal Plasma (NTP) is created in a gas by an electrical discharge or energetic electron injection. Highly reactive species (O atoms, OH, N radicals, plasma electrons) react with entrained hazardous organic chemicals in the gas, converting them to CO2, H2O, etc. NTP can be used to simultaneously remove different kinds of pollutants (eg, VOCs, SOx, NOx in flue gases). This paper presents an overview of NTP technology for pollution control and hazardous waste treatment; it is intended as an introduction to the NTP session of the symposium

  7. RESEARCH ON REVERSE OSMOSIS TREATMENT OF THE RECYCLE OF THE CONDENSATE FROM CANE MILLS TO THE BOILER SUPPLY WATER%反渗透处理糖厂二效汽凝水回用锅炉的研究

    Institute of Scientific and Technical Information of China (English)

    钮德明; 郝媛媛; 李耀熙

    2009-01-01

    The important measure to reduce energy consumption and discharge in cane mills is to use the condensate of the second effect evaporator to replace raw water as the boiler supply water. But the boilers are not used efficiently and securely when the sugar content of the condensate is too high. The condensate of the second effect evaporator has been purified carefully by using one stage reverse osmosis equipment. The results show that after the treatment, the desalination rate of the reverse osmosis system is stabilized about 87.82 % , and the effluent water quality has completely reached standards of the medium pressure boiler supply water. It is suggested that the new process of the condensate purification should be used in cane mills with medium pressure boilers.%糖厂以二效汽凝水取代原水回用锅炉是"节能减排"的重要措施,但含糖量过高的二效汽凝水回用锅炉后,将影响锅炉高效、安全使用.故此采用一级反渗透装置对二效汽凝水进行除糖净化处理.实验结果表明:反渗透系统的脱盐率能够稳定在87.82%左右,出水水质完全达到中压锅炉补充给水水质标准.建议拥有中压锅炉的糖厂采用糖厂锅炉补充给水除糖净化新工艺.

  8. APPLICATION OF REVERSE OSMOSIS TECHNOLOGY TO THE DESALINATION PROCESS IN SUPPLEMENT WATER FOR SUBMERGED ARC FURNACE%反渗透技术在矿热炉补充水除盐工艺的应用

    Institute of Scientific and Technical Information of China (English)

    吴秋勤; 曾世林; 王正

    2015-01-01

    This paper introduced the application of reverse osmosis technology to the desalination process in supplement water for submerged arc furnace. It tested the effects of original water suspended matter concentration,hardness and static pressure difference both sides of RO membrane on system operation, water yield and desalination rate. The result shows that original water suspended matter has great effects on system water production and original water hardness has less ef-fect on RO water production. It is beneficial to enhance desalination to decrease the static pressure difference both sides of RO membrane. It plays a key role in normal operation of system to increase combined deep pretreatment, decrease the original water concentration and strengthen germicide and algicide in pretreatment stage.%介绍了反渗透技术在矿热炉补充水除盐工艺中的应用,并进行了原水悬浮物浓度、硬度和RO膜两侧静压差对系统运行状况、产水量和除盐率影响的测试.结果表明,原水悬浮物对系统产水量有严重影响;原水硬度对RO产水量影响相对较小;RO膜两侧静差降低,有利于提高除盐率.增加组合深度预处理工序,降低原水的悬浮物浓度,强化预处理阶段杀菌灭藻,对除盐系统设备正常运行起关键作用.

  9. Water

    Science.gov (United States)

    ... www.girlshealth.gov/ Home Nutrition Nutrition basics Water Water Did you know that water makes up more ... to drink more water Other drinks How much water do you need? top Water is very important, ...

  10. Solubilization of water in water-in-oil microemulsions of kerosene

    Energy Technology Data Exchange (ETDEWEB)

    Andheria, A.P.; Bhagwat, S.S. [Univ. of Bombay (India)

    1995-04-01

    The incorporation of water into fuels formulated as microemulsions can offer several advantages such as fire resistance, increased flash point, and improved air-fuel contact. To this end, phase equilibria of kerosene microemulsions employing ionic and nonionic surfactants such as sodium di-(2-ethylhexyl) sulfosuccinate (AOT), lauryl diethanolamide (LDEA), nonylphenol EO-4.5 (NPEO-4.5), sorbitan monolaurate (Span-20), and cetyltrimethylammonium bromide (CTAB), as well as cosurfactants such as n-pentanol, n-hexanol, and n-heptanol, were studied. The effect of the aromaticity of the oil phase on the solubilization of water was also investigated.

  11. Contrasting effects of ozone under different water supplies in two Mediterranean tree species

    Science.gov (United States)

    Ribas, Àngela; Peñuelas, Josep; Elvira, Susana; Gimeno, Benjamín S.

    The effects of ozone (O 3) exposure under different water availabilities were studied in two Mediterranean tree species: Quercus ilex and Ceratonia siliqua. Plants were exposed to different O 3 concentrations in open top chambers (charcoal-filtered air (CF), non-filtered air (NF)) and non-filtered air plus 40 ppb v of O 3 ((7:00-17:00 solar time) (NF+)) during 2 years, and to different water regimes (IR, sample irrigation, and WS, reduced water dose to 50%) through the last of those 2 years. AOT40 in the NF+ treatment was 59265 ppb v h (from March 1999 to August 1999) while in the NF treatment, the AOT40 was 6727 ppb v h for the same period. AOT40 was always 0 in the CF treatment. WS plants presented lower stomatal conductances and net photosynthetic rates, and higher foliar N concentrations than IR plants in both species. The irrigation treatment did not change the response trends to ozone in Q. ilex, the most sensitive species to O 3 ambient concentrations, but it changed those of C. siliqua, the least sensitive species, since its ozone-fumigated WS plants did not decrease their net photosynthetic rates nor their biomass accumulation as it happened to its ozone-fumigated IR plants. These results show interspecific variations in O 3 sensitivity under different water availabilities.

  12. States of water located in the continuous organic phase of 1-butyl-3-methylimidazolium tetrafluoroborate/Triton X-100/triethylamine reverse microemulsions.

    Science.gov (United States)

    Li, Na; Cao, Quan; Gao, Yanan; Zhang, Jin; Zheng, Liqiang; Bai, Xiangtao; Dong, Bin; Li, Zhen; Zhao, Mingwei; Yu, Li

    2007-10-22

    We demonstrate a novel ionic liquid (IL) microemulsion, consisting of 1-butyl-3-methylimidazolium tetrafluoroborate (bmimBF4) and nonionic surfactant Triton X-100 prepared in triethylamine which is used either as an organic solvent or a Lewis base. The effects of small amounts of added water on the microstructure of the IL microemulsion are investigated by various techniques. UV/Vis spectroscopic analysis and FTIR spectra indicate that these water molecules are not solubilized into the IL pools of the microemulsions. 1H NMR spectra further show that the added water binds with triethylamine to form a surrounding OH- base environment. Some of OH- ions enter the palisade layers of the IL microemulsions and a continuous base interface is created. The unique solubilization behavior of water reveals that it is possible to use the triethylamine microemulsions as a template to prepare metal hydroxides as well as metal oxides in the microemulsions, which is not possible when using traditional microemulsions. PMID:17886245

  13. Water Quality Analysis of Reverse Osmosis Desalination Brine%反渗透海水淡化后浓海水的水质特点研究

    Institute of Scientific and Technical Information of China (English)

    胡海燕; 周琳

    2012-01-01

      Seawater desalination develops fast as a significant method to solve the global water resource crisis. But there are rare report about the quality of concentrated sea water. In this paper,many parameters of seawater desalination water and original seawater are analyzed. the data we got may be something useful for the water environment management and scientific study.%  作为水资源的开源增量技术,海水淡化已经成为解决全球水资源危机的重要途径。通过对浓海水的水质分析,分析了海水淡化水质状况和存在的主要问题,为水源地的水环境管理和规划提供重要科学依据。

  14. Comparison of nucleic acid extraction and reverse transcription-qPCR approaches for detection of GI and GII noroviruses in drinking water

    Science.gov (United States)

    Noroviruses (NoVs) are responsible for a number of waterborne and foodborne gastroenteritis cases each year. They are frequently associated with human sewage, and thus a potential link between wastewater discharge and contamination of source waters exists. Subsequently, contami...

  15. 利用反渗透技术的 RO -SPC超纯水系统的设计%On RO-SPC Ultra Pure Water System Using Reverse Osmosis Technology

    Institute of Scientific and Technical Information of China (English)

    黄京

    2014-01-01

    随着超纯水技术在各个行业的应用日益广泛,对超纯水的要求也越来越高,各种先进检测分析仪器也就应运而生。本文详述了如何利用反渗透技术制备超纯水的工作原理及工艺流程,在该系统中增加控制电路并采用PLC控制系统运行来监测水质。%With ultra pure water technology being applied in various industries ,requirements for the ultra pure water are increasingly high ,thus all kinds of advanced detection analy-sis instrument emerge as the times require .This paper describes the working procedure of producing ultra pure water by using reverse osmosis technology ,and explains how to moni-tor water quality by using control circuit and PLC control system .

  16. Offline solid-phase extraction for preconcentration of pharmaceuticals and personal care products in environmental water and their simultaneous determination using the reversed phase high-performance liquid chromatography method.

    Science.gov (United States)

    G Archana; Dhodapkar, Rita; Kumar, Anupama

    2016-09-01

    The present study reports a precise and simple offline solid-phase extraction (SPE) coupled with reversed-phase high-performance liquid chromatography (RP-HPLC) method for the simultaneous determination of five representative and commonly present pharmaceuticals and personal care products (PPCPs), a new class of emerging pollutants in the aquatic environment. The target list of analytes including ciprofloxacin, acetaminophen, caffeine benzophenone and irgasan were separated by a simple HPLC method. The column used was a reversed-phase C18 column, and the mobile phase was 1 % acetic acid and methanol (20:80 v/v) under isocratic conditions, at a flow rate of 1 mL min(-1). The analytes were separated and detected within 15 min using the photodiode array detector (PDA). The linearity of the calibration curves were obtained with correlation coefficients 0.98-0.99.The limit of detection (LOD), limit of quantification (LOQ), precision, accuracy and ruggedness demonstrated the reproducibility, specificity and sensitivity of the developed method. Prior to the analysis, the SPE was performed using a C18 cartridge to preconcentrate the targeted analytes from the environmental water samples. The developed method was applied to evaluate and fingerprint PPCPs in sewage collected from a residential engineering college campus, polluted water bodies such as Nag river and Pili river and the influent and effluent samples from a sewage treatment plant (STP) situated at Nagpur city, in the peak summer season. This method is useful for estimation of pollutants present in microquantities in the surface water bodies and treated sewage as compared to nanolevel pollutants detected by mass spectrometry (MS) detectors. PMID:27502523

  17. STUDY ON REMOVAL OF SULFATE FROM CIRCULATING WATER OF MINERAL PROCESSING BY REVERSE OSMOSIS%反渗透脱除选矿循环水中硫酸根的研究

    Institute of Scientific and Technical Information of China (English)

    宋敏娟; 熊守安; 张荣; 刘曙; 刘红

    2013-01-01

    Reverse osmosis was used for the treatment of sulfate from synthetic wastewater, and effects of operating rime, operating pressure as well as SO42-concentration of wastewater on separating performance of sulfete and membrane permeate flux were investigated.The actual wastewater was treated under optimal technical conditions.The results showed that under the different experimental conditions, the removal rate of sulfate from synthetic wastewater by reverse osmosis membrane was all steadily above 95%, but permeate flux changed greatly.When the operating pressure was 0.4 MPa and water temperature was 25 ℃, the removal rate of sulfate from circulating water of mineral processing was 98%.The concentration of sulfate and chloride, as well as the chroma and turbidity in the effluent all achieved the standard of GB/T 19923-2005, which met the requirements of water reuse.%采用反渗透处理废水中的SO42-,考察了运行时间、操作压力、废水中SO42-含量等因素对SO4-分离性能及膜产水量的影响,并于最佳工艺条件下处理选矿循环水.结果表明,在不同试验条件下,反渗透膜对模拟废水中SO42-的去除率均稳定在95%以上,但产水量变化较大;在操作压力0.4 MPa、温度25℃的条件下,选矿循环水中SO42-的去除率高达98%,出水中SO42-、Cl-含量及色度、浊度均达到GB/T 19923-2005标准,满足回用要求.

  18. Introduction to reversible computing

    CERN Document Server

    Perumalla, Kalyan S

    2013-01-01

    Few books comprehensively cover the software and programming aspects of reversible computing. Filling this gap, Introduction to Reversible Computing offers an expanded view of the field that includes the traditional energy-motivated hardware viewpoint as well as the emerging application-motivated software approach. Collecting scattered knowledge into one coherent account, the book provides a compendium of both classical and recently developed results on reversible computing. It explores up-and-coming theories, techniques, and tools for the application of rever

  19. Design of Reversible Counter

    OpenAIRE

    Md. Selim Al Mamun; B. K. Karmaker

    2014-01-01

    This article presents a research work on the design and synthesis of sequential circuits and flip-flops that are available in digital arena; and describes a new synthesis design of reversible counter that is optimized in terms of quantum cost, delay and garbage outputs compared to the existing designs. We proposed a new model of reversible T flip-flop in designing reversible counter.

  20. Posterior Reversible Encephalopathy Syndrome

    OpenAIRE

    J Gordon Millichap

    2013-01-01

    Investigators at Children's Hospital of Montefiore, Albert Einstein College of Medicine, NY, determined the incidence of posterior reversible encephalopathy syndrome (PRES) in a pediatric critical care unit.

  1. A model for triple helix formation on human telomerase reverse transcriptase (hTERT) promoter and stabilization by specific interactions with the water soluble perylene derivative, DAPER.

    Science.gov (United States)

    Rossetti, Luigi; D'Isa, Giuliana; Mauriello, Clementina; Varra, Michela; De Santis, Pasquale; Mayol, Luciano; Savino, Maria

    2007-08-01

    The promoter of human telomerase reverse transcriptase (hTERT) gene, in the region from -1000 to +1, contains two homopurine-homopyrimidine sequences (-835/-814 and -108/-90), that can be considered as potential targets to triple helix forming oligonucleotides (TFOs) for applying antigene strategy. We have chosen the sequence (-108/-90) on the basis of its unfavorable chromatin organization, evaluated by theoretical nucleosome positioning and nuclease hypersensitive sites mapping. On this sequence, anti-parallel triplex with satisfactory thermodynamic stability is formed by two TFOs, having different lengths. Triplex stability is significantly increased by specific interactions with the perylene derivative N,N'-bis[3,3'-(dimethylamino) propylamine]-3,4,9,10-perylenetetracarboxylic diimide (DAPER). Since DAPER is a symmetric molecule, the induced Circular Dichroism (CD) spectra in the range 400-600 nm allows us to obtain information on drug binding to triplex and duplex DNA. The drug-induced ellipticity is significantly higher in the case of triplex with respect to duplex and, surprisingly, it increases at decreasing of DNA. A model is proposed where self-stacked DAPER binds to triplex or to duplex narrow grooves. PMID:17560709

  2. Integrated Disinfection By-Products Mixtures Research: Concentration by Reverse Osmosis Membrane Techniques of Disinfection By-Products from Water Disinfected by Chlorination and Ozonation/Postchlorination

    Science.gov (United States)

    To conduct the health-effect studies described in subsequent articles in this series, concentrated aqueous mixtures of disinfection by-products were required for the two water treatment trains described in the preceding article (Miltner et al., 2008). To accomplish this, the fini...

  3. 反渗透法处理浓水存在的问题及解决方案%The Problems and Solution in Reverse Osmosis Recycling Concentrated Water

    Institute of Scientific and Technical Information of China (English)

    李松杰; 宋绍军; 聂明

    2012-01-01

    反渗透浓水中有机物含量较高,因此常发生生物污染,如果处理不当,会使反渗透系统发生严重的污染堵塞。不仅可以使膜的性能下降,还会缩短其使用寿命。通过离线清洗,并选择了合适的化学药剂进行处理,反渗透系统已经恢复正常运行。%The concentrated water has high content of organic matter.Therefore,biological contamination often occurs.If handled improperly,reverse osmosis system will plug a serious pollution.It can make the performance of membranes declined and shorten the lifetime.We conducted off-line cleaning and chose the right chemical agent.Reverse osmosis system has resumed normal operation.

  4. Treatment of Simulated Radioactive Waste Water by Reverse Osmosis%反渗透技术处理模拟核电站放射性废水中的钴

    Institute of Scientific and Technical Information of China (English)

    王欣鹏; 蒯琳萍; 车俊霞

    2011-01-01

    Aromatic polyamide composite reverse osmosis membrane was selected to treat radioactive waste water. Sodium ions and calcium ions are key metal ions contained in the low and intermediate level radioactive waste water. The effect of sodium ions, calcium ions on the retention efficiency of non-active nuclides cobalt ions and membrane permeation flux were studied under different pH values and operating pressures. The study shows that Na+ and Ca2+ in the radioactive waste water can reduce the retention efficiency of cobalt, and the depression effect of Ca2+ on the removal of cobalt is greater than the effect of Na+. The optimum process parameters are determined as follows: pH=10, operating pressure greater than 1 MPa. The retention efficiency of cobalt in radioactive waste water is maintained up to 98%. The results show that reverse osmosis can effectively remove cobalt from radioactive waste water, and meanwhile get a stable membrane flux.%选用聚酰胺反渗透膜处理模拟核电站中低放射性废水.考察了核电站中低放射性废水中主要存在的金属离子Na+、Ca2+在不同pH值及不同操作压力下对废水中钴离子的截留率及膜通量的影响.研究表明,核电站放射性废水中含有的Na+、Ca2+会降低反渗透对钴的截留率,且Ca2+对钴截留率的影响要大于Na+对钴截留率的影响.得到较优的实验条件为:在pH=10、压力大于1 MPa时,对模拟废水中钴的截留率稳定保持在98%以上.反渗透技术可以有效地去除核电站放射性废水中的钴元素,并且可以获得稳定的膜通量.

  5. Excited state intramolecular charge transfer reaction in non-aqueous reverse micelles: Effects of solvent confinement and electrolyte concentration

    Indian Academy of Sciences (India)

    Tuhin Pradhan; Harun Al Rasid Gazi; Biswajit Guchhait; Ranjit Biswas

    2012-03-01

    Steady state and time resolved fluorescence emission spectroscopy have been employed to investigate the effects of solvent confinement and electrolyte concentration on excited state intramolecular charge transfer (ICT) reaction in 4-(1-pyrrolidinyl) benzonitrile (P5C), 4-(1-piperidinyl) benzonitrile (P6C), and 4-(1-morpholenyl) benzonitrile (M6C) in AOT/n-heptane/acetonitrile and AOT/n-heptane/methanol reverse micelles. Dramatic confinement effects have been revealed via a huge reduction (factor ranging between 100 and 20) over bulk values of both equilibrium and reaction rate constants. A strong dependence on the size of the confinement () of these quantities has also been observed. dependent average static dielectric constant, viscosity and solvation time-scale have been determined. Estimated dielectric constants for confined methanol and acetonitrile show a decrease from the respective bulk values by a factor of 3-5 and viscosities increased by a factor of 2 at the highest considered. Addition of electrolyte at = 5 for acetonitrile is found to produce a linear increase of confined solvent viscosity but leads to a non-monotonic electrolyte concentration dependence of average solvation time. Reaction rate constant is found to decrease linearly with electrolyte concentration for P5C and P6C but non-monotonically for M6C, the highest decrease for all the molecules being ∼ 20% over the value in the absence of added electrolyte in the solvent pool. The observed huge reduction in reaction rate constant is attributed to the effects of decreased solution polarity, enhanced viscosity and slowed-down solvent reorganization of the solvent under confinement in these non-aqueous reverse micelles.

  6. Chemical reactions in reverse micelle systems

    Science.gov (United States)

    Matson, Dean W.; Fulton, John L.; Smith, Richard D.; Consani, Keith A.

    1993-08-24

    This invention is directed to conducting chemical reactions in reverse micelle or microemulsion systems comprising a substantially discontinuous phase including a polar fluid, typically an aqueous fluid, and a microemulsion promoter, typically a surfactant, for facilitating the formation of reverse micelles in the system. The system further includes a substantially continuous phase including a non-polar or low-polarity fluid material which is a gas under standard temperature and pressure and has a critical density, and which is generally a water-insoluble fluid in a near critical or supercritical state. Thus, the microemulsion system is maintained at a pressure and temperature such that the density of the non-polar or low-polarity fluid exceeds the critical density thereof. The method of carrying out chemical reactions generally comprises forming a first reverse micelle system including an aqueous fluid including reverse micelles in a water-insoluble fluid in the supercritical state. Then, a first reactant is introduced into the first reverse micelle system, and a chemical reaction is carried out with the first reactant to form a reaction product. In general, the first reactant can be incorporated into, and the product formed in, the reverse micelles. A second reactant can also be incorporated in the first reverse micelle system which is capable of reacting with the first reactant to form a product.

  7. Relevant factors for membrane fouling in brackish water reverse osmosis desalination%苦咸水反渗透淡化中影响膜面的污染因素∗

    Institute of Scientific and Technical Information of China (English)

    宋跃飞; 李铁梅; 周建国; 苏保卫; 高从堦

    2015-01-01

    Fouling phenomenon, type and degree in brackish water reverse osmosis ( BWRO ) desalination are significantly different from seawater reverse osmosis ( SWRO) process, due to the complex components of brackish water in different regions and the higher concentrate factor ( CF ) value in the majority of BWRO processes. Currently, membrane fouling as one of the bottlenecks for the large⁃scale BWRO application, has attracted in creasing attentions. In this review, overseas and domestic research progresses in application factors influencing the fouling on membrane surface in BWRO desalination were summarized in detail. The fouling components, fouling potential and quality indicators in water resources, and the physical properties influencing membrane fouling were introduced respectively. Two types of pretreatment methods including conventional and membrane technology were analysed, and the advantage of consistently high quality independent of influent associated with for membrane pretreatment was pointed out. In addition, the problems and suggestions for the current research status were proposed.%由于苦咸水的化学组成和浓度分布在不同地区有着显著的差异,以及淡化工艺中普遍较高的浓缩因子( concentrate factor, CF)值(在4—10之间),苦咸水反渗透( brackish water reverse osmosis, BWRO)淡化过程中的膜污染现象、类型和程度较海水反渗透( seawater reverse osmosis, SWRO)淡化过程有明显的不同。目前,膜污染已成为BWRO大规模应用于苦咸水淡化领域的瓶颈之一,如何解决这一问题成为该领域的研究热点。本文详细综述了国内外BWRO淡化过程中影响膜面污染因素的应用研究进展,重点介绍了进水来源污染成分及污染倾向、进水水质优劣指标和进水物性对膜面污染的影响;按照分离技术的不同,分类讨论了常规预处理和膜法预处理工艺,指出后者不易受进水水质变化的

  8. 煤化工反渗透浓盐水处理和回用的探讨%On the Coal Chemical iIndustry of Reverse Osmosis Concentrated Water Treatment and Reuse of

    Institute of Scientific and Technical Information of China (English)

    陈海斌

    2012-01-01

      This paper explores how to study for coal chemical reverse osmosis concentrated brine was effective for treatment and reuse of wastewater, further improve the comprehensive reuse rate, greatly reduce discharge of wastewater and waste water discharged together with the chemical oxygen demand (COD)aggregates, which for the coal chemical industry and long-term development has important sense.%  研究探讨如何针对煤化工反渗透浓盐水进行有效处理回用,进一步提高废水的综合回用率,大幅度减少废水排放量以及随废水一同排放的化学耗氧量(COD)总量,这对于煤化工行业的长远发展具有重要意义。

  9. Treatment of reverse osmosis concentrated water by ClO2 three-phase catalytic oxidation%二氧化氯三相催化氧化法处理反渗透浓水试验研究

    Institute of Scientific and Technical Information of China (English)

    李常青; 杨岳; 刘发强; 刘光利; 江岩; 巫树峰

    2011-01-01

    In view of the fact that the reverse osmosis concentrated water from wastewater reuse device of Petrochemical Corporation is hard to be biodegraded for its high CODcr. And salt concentration, C1O2 three-phase catalytic oxidation process was used to treat the said kind of wastewater. The results of the test showed that: with the aid of catalyst under the condition that the optimal active components of the catalyst was CuO/NiO/La2O3/ CeO2, the optimal mole ratio of these metal oxides was 3 : 1 : 2 : 2; when the input flow of the reverse osmosis concentrated water was 50 L/h, the mass concentration of CODcr was 95 - 230 mg/L, the optimal pH value was 6.0 - 7.0, the C1O2 dosage was 90 - 120 mg/L, the air input was 0.6 - 0.9 mVh, the reaction time was 30 min, the removal rate of CODcr. Reached above 85%, the treated reverse osmosis concentrated water quality was stable and could meet the discharge standard. Thus it could draw a conclusion that, C1O2 three-phase catalytic oxidation is a feasible and competitive technology for reverse osmosis concentrated water treatment.%针对炼化企业污水回用装置反渗透单元浓水CODCr浓度高、难生化降解以及含盐量高等特点,利用ClO2三相催化氧化法处理反渗透浓水.试验结果表明:在催化剂存在条件下,催化剂的最佳活性组成为CuO/NiO/La2O3/CeO2,活性组分的最佳物质的量之比为3∶1∶2∶2;在反渗透浓水进水量为50 L/h、进水CODCr的质量浓度为95 ~ 230 mg/L时,最佳反应pH值为6.0~7.0,ClO2投加量为90~120 mg/L,空气进气量为0.6 ~ 0.9 m3/h,反应时间为30 min,CODCr去除率大于85%,处理后的反渗透浓水可以实现稳定达标排放.C1O2三相催化氧化处理反渗透浓水是一项具有良好实用性和很强竞争力的处理方法.

  10. 基于MCGS和PLC的反渗透水处理监控系统设计%Design of reverse osmosis water treatment monitoring system base on MCGS and PLC

    Institute of Scientific and Technical Information of China (English)

    徐惠芳; 曹嘉; 伍星

    2011-01-01

    For the purpose of enhancing system reliability, improving the control precision and the passing rate of water treatment and reducing the burden on operators, a reverse osmosis water treatment monitoring system was designed based on MCCS and PLC, combining the practice in certain plant. Automatic control, centralized data management, fault alarm, and many other functions were achieved; Graphical interface displays the whole process and operates easily. It works reliably in water plant and the passing rate substantially increases, so it has a high practical value.%为了增强系统运行的可靠性,提高控制精度和水质处理合格率,同时减轻操作负担,结合某厂实际,设计了基于MCGS组态软件和可编程控制器(PLC)的反渗透水处理监控系统.此系统实现了自动控制、数据集中管理、故障报警等多方面功能,图形化的人机界面显示了设备运行全过程,操作简明快捷.在水厂的实际运行中安全可靠,出水合格率大幅提高,具有很高的实用价值.

  11. 超滤-反渗透双膜法用于中水回用的中试研究%Pilot test on the reclaimed water by a ultrafiltration/reverse osmosis process

    Institute of Scientific and Technical Information of China (English)

    李倩; 汪后港; 于萍; 罗运柏

    2013-01-01

    To reduce their fresh water consumption,Wuhan Iron and Steel (Group) Corporation has attempted to reclaim its mixed treated wastewater.Due to the high conductivity,a integrated ultrafiltration/reverse osmosis (UF/RO) system was built.The influence of effluent water quality on the UF membrane flux,trans-membrane pressure and cross-flow velocity was investigated.The backwashing period was determined.The pollution situation of UF membrane was analyzed.After advanced treatment by the UF/RO process,the conductivity of producing water was reduced to 20 μS/cm and the average desalinization ratio reached to 96.9 %.%针对钢铁企业污水处理站出水回用时存在含盐量高的问题,采用超滤-反渗透双膜法对出水进行深度处理.试验考察了武钢污水处理站出水水质对超滤膜通量、跨膜压差和膜面流速的影响,确定了超滤反洗周期,分析了超滤膜的污染情况,经双膜法深度处理后的产水电导率保持在20 μ S/cm以下,平均除盐率为96.9%.

  12. An alternative hybrid concept combining seawater desalination, solar energy and reverse electrodialysis for a sustainable production of sweet water and electrical energy

    OpenAIRE

    Brauns, E.

    2010-01-01

    Fresh water and oil/gas based energy will become scarce since their actual (increase in) consumption rate is definitely unsustainable, when considering their restricted world reserves. Moreover, the large scale burning of such fuels for the production of electrical energy or in industry/transport results in a significant rising of the carbon dioxide concentration in the atmosphere and therefore a rising of global temperatures. Research and development regarding alternative energy sources such...

  13. Lidar Observations of Low-level Wind Reversals over the Gulf of Lion and Characterization of Their Impact on the Water Vapour Variability

    OpenAIRE

    Di Girolamo Paolo; Flamant Cyrille; Cacciani Marco; Summa Donato; Stelitano Dario; Mancini Ignazio; Richard Evelyne; Ducrocq Véronique; Nuret Mathieu; Said Frédérique

    2016-01-01

    International audience Water vapour measurements from a ground-based Raman lidar and an airborne differential absorption lidar, complemented by high resolution numerical simulations from two mesoscale models (Arome-WMED and MESO-NH), are considered to investigate transition events from Mistral/Tramontane to southerly marine flow taking place over the Gulf of Lion in Southern France in the time frame September-October 2012, during the Hydrological Cycle in the Mediterranean Experiment (HyMe...

  14. 反渗透深度处理维生素C凝结水的中试研究%Pilot test on reverse osmosis to treat condensed water containing vitamin C

    Institute of Scientific and Technical Information of China (English)

    肖入峰; 刘景洋; 张建强; 孙晓明; 陈雪

    2012-01-01

    针对沈阳某药厂维生素C生产工艺中凝结水产量大、处理成本高和杂质复杂等问题,提出了采用反渗透技术对工艺凝结水进行处理.通过建立中试规模膜装置,在间歇试验和连续试验的基础上,分析了膜通量、压力、运行时间、电导率、总有机碳(TOC)等指标关系,研究了运行临界通量、清洗方式等工艺条件.反渗透系统处理效果明显,脱盐率和TOC去除率分别维持在99.9%和99%以上,该工艺切实可行.%Aiming at the problems in vitamin C production process in some pharmacy plant in Shenyang, such as large condensed water quantity, high treatment cost, and complicated impurities, the reverse osmosis process was suggested to treat the production condensed water in this paper. Based on the bench experiments and continuous experiments, this paper analyzed the relationship between the indexes of membrane flux, pressure, operation time, electrical conductivity, total organic carbon (TOC) through the pilot scale membrane facility, meanwhile, some process parameters, including the critical operation flux and cleaning method, were also studied. The reverse osmosis showed good performance in study. The desalination rate and TOC removal rate were above 9 9.9% and 99 % , respectively, which indicated that this process was applicable.

  15. Quantum reverse hypercontractivity

    Energy Technology Data Exchange (ETDEWEB)

    Cubitt, Toby [Department of Computer Science, University College London, London, United Kingdom and Centre for Quantum Information and Foundations, DAMTP, University of Cambridge, Cambridge (United Kingdom); Kastoryano, Michael [NBIA, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen (Denmark); Montanaro, Ashley [School of Mathematics, University of Bristol, Bristol (United Kingdom); Temme, Kristan [Institute for Quantum Information and Matter, California Institute of Technology, Pasadena, California 91125 (United States)

    2015-10-15

    We develop reverse versions of hypercontractive inequalities for quantum channels. By generalizing classical techniques, we prove a reverse hypercontractive inequality for tensor products of qubit depolarizing channels. We apply this to obtain a rapid mixing result for depolarizing noise applied to large subspaces and to prove bounds on a quantum generalization of non-interactive correlation distillation.

  16. Emerging micropollutants in water/wastewater: growing demand on removal technologies.

    Science.gov (United States)

    Trapido, M; Epold, I; Bolobajev, J; Dulova, N

    2014-11-01

    Developing advanced treatment technologies for improving the removal of micropollutants in water/wastewater is important. A suitable treatment is more likely to be used as the polishing step in the treatment scheme. Advanced oxidation technologies (AOTs) are relevant for removing micropollutants. The ability of direct UV photolysis and selected AOTs to degrade pharmaceuticals, endocrine-disrupting compound and herbicide has been studied and compared. The tested methods resulted in the degradation of the studied micropollutants; however, none of the methods was preferred for the removal of all tested compounds. The UV-active processes have strong potential for removal of the studied micropollutants. The utilisation of a moderate hydrogen peroxide admixture resulted in a more reliable treatment. PMID:24840356

  17. Emerging micropollutants in water/wastewater: growing demand on removal technologies.

    Science.gov (United States)

    Trapido, M; Epold, I; Bolobajev, J; Dulova, N

    2014-11-01

    Developing advanced treatment technologies for improving the removal of micropollutants in water/wastewater is important. A suitable treatment is more likely to be used as the polishing step in the treatment scheme. Advanced oxidation technologies (AOTs) are relevant for removing micropollutants. The ability of direct UV photolysis and selected AOTs to degrade pharmaceuticals, endocrine-disrupting compound and herbicide has been studied and compared. The tested methods resulted in the degradation of the studied micropollutants; however, none of the methods was preferred for the removal of all tested compounds. The UV-active processes have strong potential for removal of the studied micropollutants. The utilisation of a moderate hydrogen peroxide admixture resulted in a more reliable treatment.

  18. Climatology Analysis of Aerosol Effect on Marine Water Cloud from Long-Term Satellite Climate Data Records

    OpenAIRE

    Xuepeng Zhao; Andrew K. Heidinger; Andi Walther

    2016-01-01

    Satellite aerosol and cloud climate data records (CDRs) have been used successfully to study the aerosol indirect effect (AIE). Data from the Advanced Very High Resolution Radiometer (AVHRR) now span more than 30 years and allow these studies to be conducted from a climatology perspective. In this paper, AVHRR data are used to study the AIE on water clouds over the global oceans. Correlation analysis between aerosol optical thickness (AOT) and cloud parameters, including cloud droplet effecti...

  19. 反渗透技术用于高矿化度矿井水处理的研究%APPLICATION OF REVERSE OSMOSIS TECHNOLOGY IN THE TREATMENT OF HIGHLY MINERALIZED MINE WATER

    Institute of Scientific and Technical Information of China (English)

    杨慧敏; 何绪文; 何咏

    2009-01-01

    The reverse osmosis (RO) technology was adopted to treat mine water with high salinity,in which the removal of various ions in the mine water by the usage of CPA (Composite Polyamide) membrane were investigated. The results showed that: during the 24 d of systems operation, the treatment effect of RO process in treating the coal mine water was good, the average removal rates of various ions could reach above 98% (Ca~(2+)), above 94% (Cl~-), above 98% (SO_4~(2-)) and above 95% (Mg~(2+)) respectively, the system effluent quality is stable and the tested items of the effluent met the national drinking water standards; and the pollution characteristics of RO membrane was summarized according to the static cleaning of the polluted membrane, finally the optimal washing process was determined, that is washing the RO membrane firstly by alkali and later by acid.%采用反渗透技术对高矿化度矿井水进行处理,考察了CPA(芳香族聚酰胺)膜对矿井水中各种离子的去除效果.试验结果表明:系统运行24 d,对矿井水的处理效果显著,Ca~(2+)、Cl~-、SO_4~(2-)、Mg~(2+)各离子的平均去除率可分别达到98%、94%、98%、95%以上,系统出水水质稳定,出水达到国家饮用水标准;并根据静态清洗反渗透(RO)污染膜的分析结果,总结出反渗透膜的污染特征,最终优选出先碱洗后酸洗的膜清洗方案.

  20. An Algebra of Reversible Computation

    OpenAIRE

    Wang, Yong

    2014-01-01

    We design an axiomatization for reversible computation called reversible ACP (RACP). It has four extendible modules, basic reversible processes algebra (BRPA), algebra of reversible communicating processes (ARCP), recursion and abstraction. Just like process algebra ACP in classical computing, RACP can be treated as an axiomatization foundation for reversible computation.

  1. ELECTRIC ADSORPTION TREATMENT STUDY ON REFINERY REVERSE OSMOSIS CONDENSED WATER DESALINATION%电吸附法处理炼化反渗透浓水脱盐研究

    Institute of Scientific and Technical Information of China (English)

    张国珍; 李娜; 武福平; 杨公博; 杨仕超

    2012-01-01

    采用电吸附法对反渗透浓水进行处理,先研究了不同盐含量、电压、流量、初始pH等因素对NaCl模拟水去除效果的影响,得出适宜参数,再分别通过单级和多级电吸附法处理反渗透浓水,分析脱盐效果.结果表明,NaCl模拟水在初始电导率为2 mS/cm时,pH为7.56、电压1.8V、体积流量10 mL/min时处理效果最优,单级脱盐率达到17.18%;反渗透浓水在初始电导率为2 mS/cm时,以pH为7.17、电压为1.8 V、体积流量为10 mL/min时处理,单级脱盐率达到15.86%,经过3级处理后脱盐率达到了46.02%.%The thesis adopted electric adsorption processing to treat the reverse osmosis condensed water, first, studying simulation solution of NaCl desalination effects on some factors such as different concentrations, voltage, flow, initial pH, and obtain the best parameters by experiment condition, then by dealing with reverse osmosis condensed water to analysis desalination effect with single stage and several stages respectively. The results showed that when the initial conductivity of the simulation solution of NaCl desalination in was 2 mS/cm, pH was 7.56, the voltage was 1.8 V, the velocity was 10 mL/min, the treatment effect achieved the best, the desalination rate reached 17.18%. When the initial conductivity of condensed water was 2 mS/cm, the pH was 7.17, the voltage was 1.8 V, the velocity was 10 mL/min, the single stage desalination rate reached 15.86%, which reached 46.02% after through three stages.

  2. Analysis on reverse fault activation and water inrush possibility for coal mining above confined aquifer in a mining area%某矿区带压开采逆断层活化及突水性分析

    Institute of Scientific and Technical Information of China (English)

    卜万奎; 徐慧

    2011-01-01

    According to the geological characteristics of 732 working face in a mining area,a mechanical model was built,and the expression for normal stress and shear stress on the fault was given respectively.By calculating the normal stress and shear stress on F16 reverse fault in excavation process,it is obtained that additional normal stress and additional shear stress is produced.Additional normal stress makes the tensional fracture emergence and development within F16 fault,while additional shear stress makes the shear fracture opening within F16 fault and makes shear joint opening on both parts of F16 fault.These results lead to water permeability improved within F16 fault.On this basis,failure distribution of coal roof and seepage feature of coal floor was simulated by using RFPA2D-Flow software.The results show that there is no connected fracture channel between aquifer on other part and working face in excavation process,because the shallow depths of F16 reverse fault is compactly closed and shale on coal floor isn't destroyed.Ordovician limestone water can't burst into working face and the seepage flow on coal floor is not enough to lead to water inrush accident.%根据某矿区732工作面的实际地质特征,建立了力学模型,给出了断层位置法向应力和剪应力的计算公式,计算了该矿区在开采过程中F16逆断层面上的法向应力和剪应力,得出:随着732工作面的开挖,F16逆断层面产生附加法向应力和附加剪应力,附加的法向应力使得断层带内张性裂隙产生与发展,附加的剪应力使得断层带内剪切裂隙和断层两侧的剪节理张开,透水性增强。在此基础上,利用RFPA2D-Flow有限元软件模拟了732工作面开采过程中顶板破坏情况及底板渗流特征,结果表明:732工作面开挖过程中,由于F16逆断层浅部紧闭不导

  3. 反渗透技术处理压水堆一回路放射性废水试验研究%EXPERIMENTAL STUDY ON THE TREATMENT OF SIMULATED RADIOACTIVE WASTE WATER FROM PRIMARY LOOP BY REVERSE OSMOSIS

    Institute of Scientific and Technical Information of China (English)

    王欣鹏; 蒯琳萍; 邵嘉慧; 李雯玺

    2011-01-01

    Aromatic polyamide composite reverse osmosis was selected to treat radioactive waste water from primary loop. The radioactive waste water from primary loop contained high-concentration of boric acid. The effect of boric acid and nickel ion on the retention efficiency of non-active nuclides cobalt ions and membrane permeation flux were explored under different concentrations and operating pressures. The study showed that boric acid in the radioactive waste water could undermine the retention efficiency of cobalt. When the concentration of boric acid decreased from 2500 to 500 mg·L-1, the retention efficiency rised from 79.3% to 88.8%. The retention efficiency went up with the operation pressure, the efficiency was 86% and membrane flux was 30 m3- m-2 · s-1 at the pressure of 1.4 Mpa. The results showed that reverse osmosis can effectively remove cobalt from radioactive nuclear waste, and meanwhile got a stable membrane flux.%选用聚酰胺反渗透膜处理核电站一回路放射性废水.对反渗透去除核电站一回路放射性废水及反应堆停堆换料期间一回路排水中的钴离子进行研究.在不同操作压力及浓度下,考察废水中硼酸及镍离子对稳定核素钴的截留率影响.研究表明,一回路废水中含有的硼酸会降低反渗透对钴的截留率,硼酸质量浓度由2 500 mg·L-1下降到500 mg·L-1时,去除率由79.3%上升到88.8%.截留率及膜通量随着膜面压力上升而升高,在1.4 MPa时分别达到86%及30m3·m-2·s-1.结果说明反渗透技术可以有效地去除核电站放射性废水中的钴元素,并且可以获得稳定的膜通量.

  4. Research on reverse osmosis membrane treatment technology of condensate water containing organic acid%反渗透膜处理含有机酸凝结水技术

    Institute of Scientific and Technical Information of China (English)

    李静; 刘景洋; 乔琦; 海热提; 孙晓明

    2012-01-01

    采用反渗透膜对某制药厂含甲酸、乙酸、丙酸、丁酸、戊酸、己酸、异丁酸和2-甲基丁酸的凝结水进行处理,研究了进水温度、压力和pH值对凝结水中有机酸截留效果的影响,讨论了反渗透膜对有机酸的截留机理。研究结果表明:温度为20~40℃、压力为0.5~1.5 MPa、pH值为4~10时,产水中丁酸、戊酸、己酸和2-甲基丁酸的浓度低于检测限,甲酸、乙酸、丙酸和异丁酸的截留率随着压力和pH值增加而增大,随着温度升高而降低;产水率随着压力增大、温度升高而增大,不受pH值变化影响。说明反渗透膜对有机酸的机械筛除作用及膜与有机酸之间的电荷作用对有机酸的截留具有重要影响。%This research focused on the application of reverse osmosis membrane to treat the condensate water containing formic acid,acetic acid,propionic acid,butyric acid,pentanoic acid,carproic acid,isobutyric acid and 2-methyl-butyric acid.The effects of water temperature,pressure and pH on retention rate of organic acids,as well as the retention mechanism were discussed.The results indicated the concentration of butyric acid,pentanoic acid and 2-methyl-butyric acid in producing water were below detection limit when the experimental conditions of water temperature at 20— 40 ℃,pressure at 0.5—1.5 MPa,pH at 4—10.The retention rate of formic acid,acetic acid,propionic acid and carproic acid decreased with the increase of water temperature and increased with the increase of pressure and pH.The water production rate increased when both water temperature and pressure increased.The mechanic screening of reverse osmosis membrane and the charge effect between organic acid and membrane should have important influences on the retention effect of organic acids.

  5. On the construction of reversible automata for reversible languages

    OpenAIRE

    Lombardy, Sylvain

    2002-01-01

    International audience Reversible languages occur in many different domains. Although the decision for the membership of reversible languages was solved in 1992 by Pin, an effective construction of a reversible automaton for a reversible language was still unknown. We give in this paper a method to compute a reversible automaton from the minimal automaton of a reversible language. With this intention, we use the universal automaton of the language that can be obtained from the minimal auto...

  6. Reversible flowchart languages and the structured reversible program theorem

    DEFF Research Database (Denmark)

    Yokoyama, Tetsuo; Axelsen, Holger Bock; Glück, Robert

    2008-01-01

    Many irreversible computation models have reversible counterparts, but these are poorly understood at present. We introduce reversible flowcharts with an assertion operator and show that any reversible flowchart can be simulated by a structured reversible flowchart using only three control flow o...... justification for low-level machine code for reversible microprocessors as well as high-level block-structured reversible languages. We give examples for both such languages and illustrate them with a lossless encoder for permutations given by Dijkstra....

  7. Reverse Shoulder Arthroplasty

    Medline Plus

    Full Text Available ... stability and soft tissue envelope. In the early days of reverse arthroplasty, it used to be said ... often we'll drain these patients for a day to try to prevent hematoma formation, especially in ...

  8. Purchasing As Reverse Marketing

    OpenAIRE

    Blenkhorn, D L; Banting, P M

    1989-01-01

    This paper describes a new concept called reverse marketing, which is changing the conventional buyer-seller relationship and has important implications for the traditional role of the industrial marketer.

  9. Reversible Data Hiding Techniques

    Directory of Open Access Journals (Sweden)

    Dhananjay Yadav

    2012-03-01

    Full Text Available Reversible data hiding is a technique that is used to hide data inside an image. The data is hidden in such a way that the exact or original data is not visible. The hidden data can be retrieved as and when required. There are several methods that are used in reversible data hiding techniques like Watermarking, Lossless embedding and encryption. In this paper we present a review of reversible watermarking techniques and show different methods that are used to get reversible data hiding technique with higher embedding capacity and invisible objects. Watermark need not be hidden. Watermarking can be applied to 1. Images, 2. Text, 3. Audio/video, 4. Software.

  10. Reverse Shoulder Arthroplasty

    Medline Plus

    Full Text Available ... dislocations, although it's also reported to have a higher rate of getting the components in not perfect ... about infection and other things. There is a higher rate of infection with reverse replacement, probably because ...

  11. Reverse Shoulder Arthroplasty

    Medline Plus

    Full Text Available ... here in New York to bring you a video of a recent case of reverse shoulder arthroplasty ... helped design the system that's shown in this video, so I receive royalties and therefore have a ...

  12. Reverse Shoulder Arthroplasty

    Medline Plus

    Full Text Available ... a friction bite that if you try to work it around the corner, you can get an ... stability and soft tissue envelope. In the early days of reverse arthroplasty, it used to be said ...

  13. Reverse Shoulder Arthroplasty

    Medline Plus

    Full Text Available ... with an intact cuff, we would consider a traditional shoulder replacement. There are two basic approaches you ... less limited with the superior reverse versus the traditional. And I assume the question means the approach: ...

  14. Reverse Shoulder Arthroplasty

    Medline Plus

    Full Text Available ... the reverse allow patients to play tennis or sports where the arm swings backward. Our experience has ... who simply wants to be stronger or play sports better. But in terms of the patients that ...

  15. Reverse Shoulder Arthroplasty

    Medline Plus

    Full Text Available ... case of reverse shoulder arthroplasty for cuff deficient arthritis. You should be aware that I helped design ... in the last decade for cuff deficient shoulder arthritis in the United States. The indications are a ...

  16. Vasectomy reversal in humans

    OpenAIRE

    Bernie, Aaron M.; Osterberg, E Charles; Stahl, Peter J.; Ramasamy, Ranjith; Goldstein, Marc

    2012-01-01

    Vasectomy is the most common urological procedure in the United States with 18% of men having a vasectomy before age 45. A significant proportion of vasectomized men ultimately request vasectomy reversal, usually due to divorce and/or remarriage. Vasectomy reversal is a commonly practiced but technically demanding microsurgical procedure that restores patency of the male excurrent ductal system in 80–99.5% of cases and enables unassisted pregnancy in 40–80% of couples. The discrepancy between...

  17. PROCESSING REVERSE LOGISTICS INVENTORIES

    OpenAIRE

    Bajor, Ivona; Novačko, Luka; Ogrizović, Dario

    2014-01-01

    Developed logistics systems have organized reverse logistics flows and are continuously analyzing product returns, tending to detect patterns in oscillations of returning products in certain time periods. Inventory management in reverse logistics systems depends on different criteria, regarding goods categories, formed contracts between subjects of supply chains, uncertainty in manufacturer’s quantities of DOA (dead on arrival) products, etc. The developing logistics systems, such as the Croa...

  18. Reverse vending machine update

    Energy Technology Data Exchange (ETDEWEB)

    Rypins, S.; Papke, C.

    1986-02-01

    The document discusses reverse vending machines. Placed outdoors in supermarket parking lots or indoors in the lobby of the grocery market, these hightech machines exchange aluminum cans (or other containers in more specialized machines) for cash, coupons or redeemable receipts. The placement of reverse venders (RV) in or near supermarkets has made recycling more visible and more convenient, although the machines have yet to fully reach industry goals.

  19. Application of time reversal in underwater communication

    Institute of Scientific and Technical Information of China (English)

    LU Minghui; ZHANG Bixing; WANG Chenghao

    2004-01-01

    Time reversal is applied to the underwater spreading spectrum coding communication. On the base of analyzing the focusing characteristics of the time reversal in underwater waveguide, the time reversal is studied to overcome the wave distortion of the encoded signal caused by the multi-path effect. The experiment research for underwater coding communication is carried out in a lab water tank and the corresponding theoretical analysis is also conducted by Binary Phase Shift Keying (BPSK) encoding and Barker code with 7 chips for the spreading spectrum signal. The results show that the time reversal can improve the focusing gain and increase the ratio of the principal to the second lobe of the coding signal, and can decrease the bit error rate and increase the communication distance.

  20. Separation of water-soluble vitamins by reversed-phase high performance liquid chromatography with ultra-violet detection: application to polyvitaminated premixes.

    Science.gov (United States)

    Heudi, Olivier; Kilinç, Tamara; Fontannaz, Patric

    2005-04-01

    Nine water-soluble vitamins: [thiamine (B1), ascorbic acid (C), nicotinamide (PP), pyridoxine (B6), calcium pantothenate (B5), folic acid (B9), cyanocobalamin (B12), riboflavin (B2) and biotin (B8)] were separated on a YMC-Pack Pro C18 column (250 mm x 4.6 mm, 5 microm particle size) in a single run with a gradient elution of mobile phase consisting of 0.025% trifluoroacetic acid pH 2.6 (solvent A) and acetonitrile (solvent B). The separation was achieved within 17 min with a flow rate of 0.8 ml min(-1) and the detection was performed at two wavelengths (210 and 275 nm). The calibration graphs plotted with six concentrations of each vitamin were linear with a regression coefficient R2 > 0.995. The method was applied for the quantification of vitamins B1, C, PP, B6, B5, B9 B2 and B8 in polyvitaminated premixes (premixes) used for the fortification of infant nutrition products. The sample preparation involves an aqueous extraction of vitamins and two different samples dilution were used prior the LC-analysis. The specificity of the method was demonstrated by the retention characteristics, UV spectra and by comparing the peak purity with the standard of each vitamin. The repeatability of the method was evaluated at different level of concentrations on 12 premixes and the coefficients of variation (CVr) were below 6.5%. The values of the intermediate precision (CV1) were below 9.6% (n = 6). The concentrations of vitamins found in premixes with our method were comparable to the declared values, since no bias was found between the two sets of results at 95% confidence. The simplicity of the procedure should make it highly desirable for quality control of premixes in the food industry. PMID:15861787

  1. Solar detoxification of waste waters

    Energy Technology Data Exchange (ETDEWEB)

    Herrmann, J. M.

    2000-07-01

    Heterogeneous photocatalysis is a discipline which includes a large variety of reactions: mild or total oxidations, dehydrogenation, hydrogen transfer. oxygen-18 and deuterium isotopic exchange, metal deposition, water detoxification, gaseous pollutant removal, etc. In line with the latter point, it can be considered as one of the new Advanced Oxidation Technologies (AOT) for air and water purification treatment. Several books and reviews have been recently devoted to this problem (1-6). A recent review has reported more than 1200 references on the subject (7). Heterogeneous photocatalysis can be carried out in various media: gas phase, pure organic liquid phases or aqueous solutions. As for classical heterogeneous catalysis, the overall process can be decomposed into five independent steps: 1. Transfer of the reactants in the fluid to the surface. 2. Adsorption of a least one of the reactants. 3. Reaction in the adsorbed phase 4. Desorption of the product (s) 5. Removal of the products from the interface region. (Author) 11 refs.

  2. Solar Detoxification of Waste Waters

    Energy Technology Data Exchange (ETDEWEB)

    Herrmann, J.M.

    2002-07-01

    Heterogeneous photocatalysis is a discipline which includes a large variety of reactions: mild or total oxidations, dehydrogenation, hydrogen transfer, oxygen-18 and deuterium isotopic exchange, metal deposition, water detoxification, gaseous pollutant removal, etc. In line with the latter point, it can be considered as one of the new. Advanced Oxidation Technologies (AOT) for air and water purification treatment. Several books and reviews have been recently devoted to this problem (1-6). A recent review has reported more than 1200 references on the subject. Heterogeneous photocatalysis can be carried out in various media: gas phase, pure organic liquid phases or aqueous solutions. As for classical heterogeneous catalysis, the overall process can be decomposed into five independent steps: 1. Transfer of the reactants in the fluid phase to the surface 2. Adsorption of a least one of the reactants 3. Reaction in the adsorbed phase 4. Desorption of the products 5. Removal of the products from the interface region. (Author)

  3. Effect of Replacement of New Reverse Osmosis Film of Water Purification System to Clinical Biochemistry%实验室纯水系统更换反渗透膜对生化检验的影响

    Institute of Scientific and Technical Information of China (English)

    莫基浩; 刘鲜茹; 李少侠

    2014-01-01

    目的:研究实验室纯水系统更换新反渗透膜后,所产纯水的质量是否符合生化检验的要求并评价其影响。方法通过Beckman Coulter生化分析系统配套纯水机天创TCHS-RO/100A自带电阻表和 HM COM-100电导率测量笔连续监测新产纯水中的实时离子含量。用正常纯水在 AU680上重复20次测量 ALT,AST,TBIL,ALP,GGT,TP,ALB,BUN, CR,UA,GLU,TC,TG,HDL,LDL,CK,LDH,P,Ca(对照组),更换为新产纯水后进行相同试验操作(试验组),以评估新产纯水对生化分析的影响。连续5天,每天3次(间隔2 h)监测新产纯水的 TG试剂空白,监测水中甘油水平。结果开机30 min后,HM COM-100测得电导率降至(0.1±0.0)μS/cm,机载电阻表测得新产纯水在开机50 min后稳定在18.25 MΩcm。在用 AU680进行生化分析时,对照组中TG测量值=1.04 mmol/L,试验组=21.39 mmol/L,差异有统计学意义(P<0.01),而除TG其他生化项目偏倚均在5%以内,CV<1/4CLIA’88,差异无统计学意义(P>0.05)。TG试剂空白在第5天稳定在A660nm=0.0156±0.0004。结论新纯水系统在生产约2800 L水后,所产纯水中的甘油可以清除干净。实验室纯水系统在更换反渗透膜后,需要对水质进行连续监测,以评价其对常规生化项目检测的影响。%Objective To test if the quality of produced water could come up to the standards of clinical biochemistry,and e-valuate the effect of the produced water after replacement of a new reverse osmosis film of the laboratory water purification system.Methods The ion concentration of the produced water was tested by ohmmeter in Beckman Coulter supporting TianChuang water purification system TCHS-RO/100A and HM COM-100 conductivity meter.The biochemical index ALT,AST,TBIL,ALP,GGT,TP,ALB,BUN,CR,UA,GLU,TC,TG,HDL,LDL,CK,LDH,P,Ca of mixed serum were tested 20 times by AU680 under the condition of

  4. Reverse electrodialysis : evaluation of suitable electrode systems

    NARCIS (Netherlands)

    Veerman, J.; Saakes, M.; Metz, S. J.; Harmsen, G. J.

    2010-01-01

    Reverse electrodialysis (RED) is a method for directly extracting electrical energy from salinity gradients, especially from sea and river water. For the commercial implementation of RED, the electrode system is a key component. In this paper, novel electrode systems for RED were compared with exist

  5. Reversed extension flow

    DEFF Research Database (Denmark)

    Nielsen, Jens Kromann; Rasmussen, Henrik K.

    2008-01-01

    Afilament stretching rheometer (FSR) was used for measuring the start-up of uni-axial elongational flow followed by reversed bi-axial flow, both with a constant elongational rate. A narrow molecular mass distribution linear polystyrene with a molecular weight of 145 kg / mole wis subjected...... to the start-up of elongation for three Hencky strain units and subsequently the reversed flow. The integral molecular stress function formulation within the 'interchain pressure' concept agrees with the experiments. In the experiments the Hencky strain at which the str~ss becomes zero (the recovery strain......) in the reversed flow has been identified. The recovery strain is found to increase with elongational rate, and has a maximum value of approximately 1.45. The Doi Edwards model using any stretch evolution equation is not able to predict the correct level of the recovery strain....

  6. REVIEWS OF TOPICAL PROBLEMS: Waves and patterns in reaction-diffusion systems. Belousov-Zhabotinsky reaction in water-in-oil microemulsions

    Science.gov (United States)

    Vanag, Vladimir K.

    2004-09-01

    Advances in nonequilibrium pattern formation in reaction-diffusion systems are reviewed. Special emphasis is placed on patterns found in the spatially extended Belousov-Zhabotinsky reaction dispersed in aerosol OT water-in-oil microemulsions (BZ-AOT system): Turing patterns, packet and standing waves, antispirals and segmented spirals, and accelerating waves and oscillons. All experimental results are explained theoretically and reproduced in computer simulations.

  7. Treatment of Reverse Osmosis Concentrated Water in Refinery by Biological Activated Carbon Process%生物活性炭工艺处理炼油厂反渗透浓缩水

    Institute of Scientific and Technical Information of China (English)

    徐传海; 魏新; 郦和生; 王岽

    2011-01-01

    The reverse osmosis concentrated water in refinery was treated by biological activated carbon process. Under the conditions of cracked-anthracite-made activated carbon size 2. 4 -5. 9 mm, influent pH 7. 5, empty bed residence time 30 min and average influent COD 100 mg/L, the system can keep stable running for 48 d, the average removal rates of COD and A2Si are 50% and 77% respectively, and the effluent COD is below 60 mg/L, which can meet the first grade discharge standard of GB8978 - 1996.%采用生物活性炭工艺处理炼油厂反渗透浓缩水.在无烟煤破碎炭粒径为2.4~5.9 mm、进水pH为7.5、空床停留时间为30 min、平均进水COD为100 mg/L的条件下,系统可稳定运行48 d,平均COD去除率为50%,平均A254(反渗透浓缩水在波长254 nm处的吸光度)降低率为77%,出水COD低于60 mg/L,达到GB8978-1996《污水综合排放标准》中的一级排放标准.

  8. Chemical recycling of carbon dioxide emissions from a cement plant into dimethyl ether, a case study of an integrated process in France using a Reverse Water Gas Shift (RWGS) step

    International Nuclear Information System (INIS)

    Recycling of carbon dioxide (CO2) and hydrogen (H2) into liquid fuel technology has recently gained wide public interest since it is a potential pathway to increase the liquid fuel supply and to mitigate CO2 emissions simultaneously. In France, the majority of the electricity production is derived from nuclear and renewable energy which have a low CO2 footprint. This electricity power enables a potential for massive hydrogen production with low carbon emissions. We studied the possibility to develop this technology at an industrial scale in the French context on a typical industrial example of a cement manufacture in the south of France. An integrated process is proposed, which enables the use of the heat released by the CO2 to fuel process to help to capture the CO2 released by the cement manufacture. Some technological issues are discussed, and a potential solution is proposed for the catalyst used in the critical step of the Reverse Water Gas-Shift reaction (RWGS) of the process. (authors)

  9. Radiation controlling reversible window

    Energy Technology Data Exchange (ETDEWEB)

    Gell, H.A. Jr.

    1980-01-01

    A coated glass glazing system is presented including a transparent glass substrate having one surface coated with a radiation absorptive film which is overcoated with a radiation reflective film by a technique which renders the radiation reflective film radiation absorptive at the surface contracting the radiating absorptive film. The coated glass system is used as glazing for storm windows which are adapted to be reversible so that the radiation reflective surface may be exposed to the outside of the dwelling during the warm seasons to prevent excessive solar radiation from entering a dwelling and reversed during cold seasons to absorb solar radiation and utilize it to aid in keeping the dwelling interior warm.

  10. 微萃取/反相液相色谱法测定水中苯甲酰脲类农药%Determination of Benzoylurea Insecticides in Water by Microextraction Flask/Reversed-phase Liquid Chromatography

    Institute of Scientific and Technical Information of China (English)

    周建科; 杨冬霞; 徐鹏

    2011-01-01

    A method using microextraction enrichment and reversed-phase high-performance liquid chromatography was used for determination of benzoylurea insecticides in surface water.The sample was extracted by isooctane.Benzoylurea insecticides were separated on Diamonsil C18 column with acetonitrile∶ methanol∶ water= 20∶ 65∶ 15 as mobile phase and determined using UV detector at 260 nm.For triflumuron, hexaflumuron and teflubenzuron, the average recoveries are 92.23%, 102.18% and 89.77% respectively.The relative standard deviations are less than 5.7%.The linearity is good in the range of 0.5 to 100 μg/mL with the correlation coefficients of equal to or more than 0.999 8.%以异辛烷作萃取剂,采用微萃取瓶富集,用反相高效液相色谱法测定地表水中的苯甲酰脲类农药.检测条件如下:Diamonsil C色谱柱,乙腈:甲醇:水=20:65:15流动相,260 nm紫外检测.该方法检测杀铃脲、氟铃脲和氟苯脲的平均回收率分别为92.23%、102.18%和89.77%,相对标准偏差<5.7%,在0.5~100μg/mL范围内三组分线性良好,相关系数≥0.999 8.

  11. Characterization of hereditarily reversible posets

    OpenAIRE

    Kukieła, Michał

    2013-01-01

    A poset P is called reversible if every order preserving bijective self map of P is an order automorphism. P is called hereditarily reversible if every subposet of P is reversible. We give a complete characterization of hereditarily reversible posets in terms of forbidden subsets. A similar result is stated also for preordered sets. As a corollary we extend the list of known examples of hereditarily reversible topological spaces.

  12. 利用反渗透浓排水代替深井水制取液体氯化钡的实验研究%Experimental study of using of reverse osmosis concentrated drainage insteading of deep well water preparing liquid barium chloride

    Institute of Scientific and Technical Information of China (English)

    王春红; 王会昌

    2011-01-01

    介绍了用反渗透浓排水代替深井水制备氯化钡的实验情况。实验结果表明,用反渗透浓排水制备氯化钡是可行的。%The experimental condition of using reverse osmosis concentrated drainage insteading of deep well water preparing barium chloride was introduced.The results show that using reverse osmosis concentrated drainage preparing barium chloride was feasible.

  13. Reverse Coherent Information

    OpenAIRE

    García-Patrón, Raúl; Pirandola, Stefano; Lloyd, Seth; Shapiro, Jeffrey H.

    2008-01-01

    In this letter we define a family of entanglement distribution protocols assisted by feedback classical communication that gives an operational interpretation to reverse coherent information, i.e., the symmetric counterpart of the well known coherent information. This lead to the definition of a new entanglement distribution capacity that exceeds the unassisted capacity for some interesting channels.

  14. Reverse Coherent Information

    Science.gov (United States)

    García-Patrón, Raúl; Pirandola, Stefano; Lloyd, Seth; Shapiro, Jeffrey H.

    2009-05-01

    In this Letter we define a family of entanglement distribution protocols assisted by feedback classical communication that gives an operational interpretation to reverse coherent information, i.e., the symmetric counterpart of the well-known coherent information. This leads to the definition of a new entanglement distribution capacity that exceeds the unassisted capacity for some interesting channels.

  15. Reversible focal splenial lesions

    Energy Technology Data Exchange (ETDEWEB)

    Gallucci, Massimo; Limbucci, Nicola [University of L' Aquila, Department of Radiology, S. Salvatore Hospital, L' Aquila (Italy); Paonessa, Amalia [Loreto Nuovo Hospital, Department of Neuroradiology, Napoli (Italy); Caranci, Ferdinando [Federico II University, Department of Neurological Sciences, Napoli (Italy)

    2007-07-15

    Reversible focal lesions in the splenium of the corpus callosum (SCC) have recently been reported.They are circumscribed and located in the median aspect of the SCC. On MRI, they are hyperintense on T2-W and iso-hypointense on T1-W sequences, with no contrast enhancement. On DWI, SCC lesions are hyperintense with low ADC values, reflecting restricted diffusion due to cytotoxic edema. The common element is the disappearance of imaging abnormalities with time, including normalization of DWI. Clinical improvement is often reported. The most established and frequent causes of reversible focal lesions of the SCC are viral encephalitis, antiepileptic drug toxicity/withdrawal and hypoglycemic encephalopathy. Many other causes have been reported, including traumatic axonal injury. The similar clinical and imaging features suggest a common mechanism induced by different pathological events leading to the same results. Edema and diffusion restriction in focal reversible lesions of the SCC have been attributed to excitotoxic mechanisms that can result from different mechanisms; no unifying relationship has been found to explain all the pathologies associated with SCC lesions. In our opinion, the similar imaging, clinical and prognostic aspects of these lesions depend on a high vulnerability of the SCC to excitotoxic edema and are less dependent on the underlying pathology. In this review, the relevant literature concerning reversible focal lesions in the SCC is analyzed and hypotheses about their pathogenesis are proposed. (orig.)

  16. On reverse hypercontractivity

    CERN Document Server

    Mossel, Elchanan; Sen, Arnab

    2011-01-01

    We study the notion of reverse hypercontractivity. We show that reverse hypercontractive inequalities are implied by standard hypercontractive inequalities as well as by the modified log-Sobolev inequality. Our proof is based on a new comparison lemma for Dirichlet forms and an extension of the Strook-Varapolos inequality. A consequence of our analysis is that {\\em all} simple operators $L=Id-\\E$ as well as their tensors satisfy uniform reverse hypercontractive inequalities. That is, for all $qreverse hypercontractive inequalities established here imply new mixing and isoperimetric results for short random walks in product spaces, for certain card-shufflings, for Glauber dynamics in high-temperat...

  17. Reversing insect pollinator decline

    OpenAIRE

    Potts, Simon; Wentworth, Jonathan

    2013-01-01

    Pollination by insects enables the reproduction of flowering plants and is critical to UK agriculture.1 Insect pollinators have declined globally, with implications for food security and wild habitats. This POSTnote summarises the causes for the recent trends, gaps in knowledge and possible strategies for reversing pollinator decline.

  18. Reverse Shoulder Arthroplasty

    Medline Plus

    Full Text Available Reverse Shoulder Arthroplasty Zimmer, Inc. New York City, New York March 17, 2010 Welcome to this OR Live presentation, brought to you by Zimmer. Hi. I'm ... my partner, Brad Parsons. We're here in New York to bring you a video of a ...

  19. 反渗透膜处理维生素C凝结水的最优工艺条件%Optimum technological conditions of reverse osmosis processing VC condensation water

    Institute of Scientific and Technical Information of China (English)

    肖入峰; 刘景洋; 张建强

    2012-01-01

    Problems in the condensate water of vitamin C production project, such as its large amount, diffi- culties in disposal, storage and transport and low nutrients were analyzed in this paper, and the reverse osmosis technology was put forward accordingly. Through setting up the small sale pilot of reverse osmosis technology e- quipment and adopting the dimensionless multiple regression analysis method, relationship between operating con- ditions index and permeate water evaluation index was analyzed based on the batch experiments, the degree of the operating conditions index impacting on the permeate water evaluation indexes was quantitatively evaluated, and based on this research the optimal process parameters of the operating conditions were studied. The results show that the dimensionless multiple regression analysis method is practical and effective. In the range of orthogonal experi- ment design level, the operation pressure, pH and reflux ratio are all remarkable influencing factors of the multi-target system, and the sequence of influence degree size is :pressure 〉 pH 〉 reflux ratio 〉 temperature ,and the percentages of each factor are 43.02%, 29.01%, 25.07% and 2.89%, respectively. The influence of each operation index on the system is independent. If not to consider the membrane pollution but only the system benefits, the optimal operating conditions are temperature of 30.65℃, pressure of 1.5 MPa, reflux ratio of 0.78 and pH of 7. 475.%针对维生素C生产工艺中产生的凝结水产量大、处理成本高、存储运输困难和营养物质含量偏低等问题,采用反渗透技术对VC凝结水进行处理。实验建立小试规模反渗透膜处理装置,采用无量纲化多元回归分析方法,分析了操作条件指标与渗透水评价指标两套指标体系之间的关系,定量评价了各个操作条件指标对渗透水评价指标的整体影响程度,并在此基础上研究了最佳操作条件的工艺参数。结

  20. Reversible quantum cellular automata

    CERN Document Server

    Schumacher, B

    2004-01-01

    We define quantum cellular automata as infinite quantum lattice systems with discrete time dynamics, such that the time step commutes with lattice translations and has strictly finite propagation speed. In contrast to earlier definitions this allows us to give an explicit characterization of all local rules generating such automata. The same local rules also generate the global time step for automata with periodic boundary conditions. Our main structure theorem asserts that any quantum cellular automaton is structurally reversible, i.e., that it can be obtained by applying two blockwise unitary operations in a generalized Margolus partitioning scheme. This implies that, in contrast to the classical case, the inverse of a nearest neighbor quantum cellular automaton is again a nearest neighbor automaton. We present several construction methods for quantum cellular automata, based on unitaries commuting with their translates, on the quantization of (arbitrary) reversible classical cellular automata, on quantum c...

  1. Study on Health Safety of Fine Drinking Water by Reverse Osmosis Membrane%反渗透膜制终端直饮水的健康安全性考察

    Institute of Scientific and Technical Information of China (English)

    庞小燕; 宿程远; 黄小玲; 吕明; 陈晶; 黄意

    2011-01-01

    通过动态试验,考察了反渗透膜制终端直饮水系统对有机物、TDS、氨氮、UV254以及硝酸盐等的去除效果;同时分析了进水UV254与CODMn的相关性。试验表明:该系统对CODMnTDS与硝酸盐氮的平均去除率分别为60%、95%和86%,出水的氨氮浓度基本为0;该系统对UV25。的平均去除率为90%,可保证饮水水质安全;同时试验表明进水UV254与CODMn之间有一定的相关性。%The removal effects for organic matters, TDS, NH4 -N, UV254 and nitrate nitrogen by reverse osmosis (RO) system were reviewed through dynamic experiments. This paper also analyzes the correlation between the inflow CODMn and UV254. The results showed that the removal rates of CODM., TDS and nitrate nitrogen by RO system were 60%, 95% and 86% respectively. The NH4 - N concentration of effluent was nearly zero. The average UV254 removal rate was 90%. The health safety of the drinking water is secured and the experiments also proved a certain degree of correlation between the inflow UV254 and CODMn.

  2. Reversible Multi-Head Finite Automata Characterize Reversible Logarithmic Space

    DEFF Research Database (Denmark)

    Axelsen, Holger Bock

    2012-01-01

    Deterministic and non-deterministic multi-head finite automata are known to characterize the deterministic and non- deterministic logarithmic space complexity classes, respectively. Recently, Morita introduced reversible multi-head finite automata (RMFAs), and posed the question of whether RMFAs...... characterize reversible logarithmic space as well. Here, we resolve the question affirmatively, by exhibiting a clean RMFA simulation of logarithmic space reversible Turing machines. Indirectly, this also proves that reversible and deterministic multi-head finite automata recognize the same languages....

  3. Reversible watermarking for images

    Science.gov (United States)

    van Leest, Arno J.; van der Veen, Michiel; Bruekers, Fons

    2004-06-01

    Reversible watermarking is a technique for embedding data in a digital host signal in such a manner that the original host signal can be restored in a bit-exact manner in the restoration process. In this paper, we present a general framework for reversible watermarking in multi-media signals. A mapping function, which is in general neither injective nor surjective, is used to map the input signal to a perceptually equivalent output signal. The resulting unused sample values of the output signal are used to encode additional (watermark) information and restoration data. At the 2003 SPIE conference, examples of this technique applied to digital audio were presented. In this paper we concentrate on color and gray-scale images. A particular challenge in this context is not only the optimization of rate-distortion, but also the measure of perceptual quality (i.e. the distortion). In literature distortion is often expressed in terms of PSNR, making comparison among different techniques relatively straightforward. We show that our general framework for reversible watermarking applies to digital images and that results can be presented in terms of PSNR rate-distortions. However, the framework allows for more subtle signal manipulations that are not easily expressed in terms of PSNR distortion. These changes involve manipulations of contrast and/or saturation.

  4. 油包水微乳液中抗体酶催化布洛芬酯选择性水解的酶学特性%Enzymological Characteristics of Catalytic Antibody-catalyzed enantioselective Hydrolysis of Ibuprofen Ester in Water-in-oil microemulsion

    Institute of Scientific and Technical Information of China (English)

    杨根生; 戚映丹; 欧志敏; 姚善泾

    2009-01-01

    The asymmetric hydrolyzation of racemic ibuprofen ester is one of the most important methods for chiral separation of ibuprofen. A catalytic antibody that accelerates the rate of enantioselective hydrolysis of ibuprofen methyl ester was successfully elicited against an immunogen consisting of tetrahedral sulfate hapten attached to bovine serum albumin (BSA). The rate constant enhancement factor Kcat/Kuncat was about 1.6x104. The catalytic activity of the catalytic antibody in a reverse micelle reaction system based on sodium b/s (2-ethylhexyl) sodium sulfosuccinate (AOT) in isooctane was studied. Kinetic analysis of the catalytic antibody-catalyzed reaction was found to be possible in this system. Kinetic studies showed that hydrolysis in the microemulsion system follow Michaelis-Menten kinetics. The catalytic antibody can also accelerate catalysis of S-ibuprofen methyl ester in the microemulsion system. Temperature effects, the pH profile, Km,app and Kcat were determined. The dependence of the catalytic antibody hydrolytic activity on the Wo (molar ratio of water to surfactant) showed a bell-shaped curve, presenting a maximum at about wo = 21.%根据过渡态理论设计和合成了能诱导产生催化选择性水解布洛芬甲酯的催化抗体的四面体硫酸盐半抗原,并与牛血清白蛋白(BSA)偶联制备成免疫源,通过免疫手段成功筛选出具有加速选择性水解生成S-布洛芬的特异性催化抗体.其Kcat,app/Kuncat,app达1.6x104.进一步地将催化抗体运用到W/O微乳体系(反胶束)中进行布洛芬酯的选择性水解研究,其动力学研究证明其催化过程同样遵循Michaelis.Menten方程.考察了pH值和温度对催化初速度影响,Wo(体系中水和琥珀酸二辛酯磺酸钠(AOT)的摩尔比)对催化初速度影响呈现为钟罩型,最适的Wo.为21.

  5. Distance dependence of magnetic field effect inside confined environment of reverse micelles

    Science.gov (United States)

    Sarangi, Manas Kumar; Basu, Samita

    2013-06-01

    In this article, we emphasize on the distance dependence of the magnetic field effect (MFE) on the donoracceptor (D-A) pair inside the confined environment of AOT/H2O/n-heptane reverse micellar (RMs) system. For this study N, N-dimethyl aniline (DMA) is used as an electron donor while the protonated form of Acr is treated as an electron acceptor. We report of the occurrence of an associated excited state proton transfer with the photoinduced electron transfer between Acr and DMA forming corresponding radical pair (RP) and radical ion pairs (RIP). The fate of these reaction products has been tested in the presence of an external magnetic field (˜0.08T) by varying the size of the RMs. The MFE between Acr and DMA has been compared to the results with the earlier reported interactions between Acr and TEA (Chemical Physics Letters, 2011, 506, 205-210). We accentuate the importance of the localization of the D and A inside the RMs, and the intervening distance between the pair to be the critical component for observing substantial MFE.

  6. Preparations of nanosized TiO{sub 2} in reverse microemulsion and their photocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Man Sig; Lee, Gun-Dae; Ju, Chang-Sik; Hong, Seong-Soo [Division of Chemical Engineering, Pukyong National University, San 100 Yongdang-dong, Nam-Ku, Pusan 608-739 (Korea, Republic of)

    2005-09-15

    Nanosized titania sol has been produced by the controlled hydrolysis of titanium tetraisopropoxide (TTIP) in sodium bis(2-ethylhexyl)sulfosuccinate (AOT) reverse micelles. The physical properties, such as surface area, crystallite size and crystallinity according to R and W{sub 0} ratio, have been investigated by TEM, XRD, BET, FT-IR, TGA and DTA. In addition, the photocatalytic decomposition of p-nitrophenol has been studied by using a batch reactor in the presence of UV light in order to compare the photocatalytic activity of prepared nanosized titania. It is shown that the anatase structure appears in the 300-600{sup o}C calcination temperature range and the transformation of anatase into rutile starts above 700{sup o}C. The crystallite size increases with increasing R and W{sub 0} ratio but W{sub 0} ratio shows a stronger effect on the crystallite size than R ratio. In the photocatalytic decomposition of p-nitrophenol, the photocatalytic activity is mainly determined by the crystallinity of titania. In addition, the titania calcined at 500{sup o}C shows the highest activity on the photocatalytic decomposition of p-nitrophenol(k=5.6x10{sup -3}min{sup -1}) and the pure anatase structure.

  7. Designing Parity Preserving Reversible Circuits

    OpenAIRE

    Paul, Goutam; Chattopadhyay, Anupam; Chandak, Chander

    2013-01-01

    Making a reversible circuit fault-tolerant is much more difficult than classical circuit and there have been only a few works in the area of parity-preserving reversible logic design. Moreover, all of these designs are ad hoc, based on some pre-defined parity preserving reversible gates as building blocks. In this paper, we for the first time propose a novel and systematic approach towards parity preserving reversible circuits design. We provide some related theoretical results and give two a...

  8. Reverse Engineering of RFID devices

    OpenAIRE

    Bokslag, Wouter

    2015-01-01

    This paper discusses the relevance and potential impact of both RFID and reverse engineering of RFID technology, followed by a discussion of common protocols and internals of RFID technology. The focus of the paper is on providing an overview of the different approaches to reverse engineering RFID technology and possible countermeasures that could limit the potential of such reverse engineering attempts.

  9. Graphite-teflon composite bienzyme electrodes for the determination of cholesterol in reversed micelles. Application to food samples.

    Science.gov (United States)

    Peña, N; Ruiz, G; Reviejo, A J; Pingarrón, J M

    2001-03-15

    A bienzyme amperometric composite biosensor for the determination of free and total cholesterol in food samples is reported. Cholesterol oxidase and horseradish peroxidase, together with potassium ferrocyanide as a mediator, are incorporated into a graphite-70% Teflon matrix. The compatibility of this biosensor design with predominantly nonaqueous media allows the use of reversed micelles as working medium. The reversed micelles are formed with ethyl acetate as continuous phase (in which cholesterol is soluble), a 4% final concentration of 0.05 mol L(-1) phosphate buffer solution, pH 7.4, as dispersed phase, and 0.1 mol L(-1) AOT as emulsifying agent. Studies on the repeatability of the amperometric response obtained at +0.10 V, with and without regeneration of the electrode surface by polishing, on the useful lifetime of one single biosensor and on the reproducibility in the fabrication of different pellets illustrate the robustness of the biosensor design. Determination of free and total cholesterol in food samples such as butter, lard, and egg yoke was carried out, and the obtained results were advantageously compared with those provided by using a commercial Boehringer test kit. PMID:11305650

  10. Reversible brazing process

    Science.gov (United States)

    Pierce, Jim D.; Stephens, John J.; Walker, Charles A.

    1999-01-01

    A method of reversibly brazing surfaces together. An interface is affixed to each surface. The interfaces can be affixed by processes such as mechanical joining, welding, or brazing. The two interfaces are then brazed together using a brazing process that does not defeat the surface to interface joint. Interfaces of materials such as Ni-200 can be affixed to metallic surfaces by welding or by brazing with a first braze alloy. The Ni-200 interfaces can then be brazed together using a second braze alloy. The second braze alloy can be chosen so that it minimally alters the properties of the interfaces to allow multiple braze, heat and disassemble, rebraze cycles.

  11. Fundamentals of reversible flowchart languages

    DEFF Research Database (Denmark)

    Yokoyama, Tetsuo; Axelsen, Holger Bock; Glück, Robert

    2016-01-01

    . Although reversible flowcharts are superficially similar to classical flowcharts, there are crucial differences: atomic steps are limited to locally invertible operations, and join points require an explicit orthogonalizing conditional expression. Despite these constraints, we show that reversible......Abstract This paper presents the fundamentals of reversible flowcharts. They are intended to naturally represent the structure and control flow of reversible (imperative) programming languages in a simple computation model, in the same way classical flowcharts do for conventional languages......, structured reversible flowcharts are as expressive as unstructured ones, as shown by a reversible version of the classic Structured Program Theorem. We illustrate how reversible flowcharts can be concretized with two example programming languages, complete with syntax and semantics: a low-level unstructured...

  12. Reversibly Bistable Flexible Electronics

    KAUST Repository

    Alfaraj, Nasir

    2015-05-01

    Introducing the notion of transformational silicon electronics has paved the way for integrating various applications with silicon-based, modern, high-performance electronic circuits that are mechanically flexible and optically semitransparent. While maintaining large-scale production and prototyping rapidity, this flexible and translucent scheme demonstrates the potential to transform conventionally stiff electronic devices into thin and foldable ones without compromising long-term performance and reliability. In this work, we report on the fabrication and characterization of reversibly bistable flexible electronic switches that utilize flexible n-channel metal-oxide-semiconductor field-effect transistors. The transistors are fabricated initially on rigid (100) silicon substrates before they are peeled off. They can be used to control flexible batches of light-emitting diodes, demonstrating both the relative ease of scaling at minimum cost and maximum reliability and the feasibility of integration. The peeled-off silicon fabric is about 25 µm thick. The fabricated devices are transferred to a reversibly bistable flexible platform through which, for example, a flexible smartphone can be wrapped around a user’s wrist and can also be set back to its original mechanical position. Buckling and cyclic bending of such host platforms brings a completely new dimension to the development of flexible electronics, especially rollable displays.

  13. Reversible posterior leukoencephalopathy syndrome

    International Nuclear Information System (INIS)

    To review reversible posterior leukoencephalopathy syndrome. We reviewed 22 patients (M:F=3:19; age, 17-46 years) with the characteristic clinical and imaging features of reversible posterior leukoencephalopathy syndrome. All underwent brain MRI, and in three cases both CT and MRI were performed. In one, MRA was obtained, and in eleven, follow-up MR images were obtained. We evaluated the causes of this syndrome, its clinical manifestations, and MR findings including the locations of lesions, the presence or absence of contrast enhancement, and the changes seen at follow-up MRI. Of the 22 patients, 13 had eclampsia (six during pregnancy and seven during puerperium). Four were receiving immunosuppressive therapy (three, cyclosporine ; one, FK 506). Four suffered renal failure and one had complicated migraine. The clinical manifestations included headache (n=12), visual disturbance (n=13), seizure (n=15), focal neurologic sign (n=3), and altered mental status (n=2). Fifteen patients had hypertension and the others normotension. MRI revealed that lesions were bilateral (n=20) or unilateral (n=2). In all patients the lesion was found in the cortical and subcortical areas of the parieto-occipital lobes ; other locations were the basal ganglia (n=9), posterior temporal lobe (n=8), frontal lobe (n=5), cerebellum (n=5), pons (n=2), and thalamus (n=1). All lesions were of high signal intensity on T2-weighted images, and of iso to low intensity on T1-weighted images. One was combined with acute hematoma in the left basal ganglia. In eight of 11 patients who underwent postcontrast T1-weighted MRI, there was no definite enhancement ; in one, enhancement was mild, and in tow, patchy. CT studies showed low attenuation, and MRA revealed mild vasospasm. The symptoms of all patients improved. Follow-up MRI in nine of 11 patients depicted complete resolution of the lesions ; in two, small infarctions remained but the extent of the lesions had decreased. Reversible posterior

  14. Reversible posterior leukoencephalopathy syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Eun Ja; Yu, Won Jong; Ahn, Kook Jin; Jung, So Lyung; Lee, Yeon Soo; Kim, Ji Chang; Kang, Si Won [The Catholic Univ. of Korea, Taejon (Korea, Republic of); Song, Chang Joon [Chungnam National Univ. School of Medicine, Cheonju (Korea, Republic of); Song, Soon-Young; Koo, Ja Hong [Kwandong Univ. College of Medicine, Myungji Hospital, Seoul (Korea, Republic of); Kim, Man Deuk [College of Medicine Pochon CHA Univ., Seoul (Korea, Republic of)

    2001-10-01

    To review reversible posterior leukoencephalopathy syndrome. We reviewed 22 patients (M:F=3:19; age, 17-46 years) with the characteristic clinical and imaging features of reversible posterior leukoencephalopathy syndrome. All underwent brain MRI, and in three cases both CT and MRI were performed. In one, MRA was obtained, and in eleven, follow-up MR images were obtained. We evaluated the causes of this syndrome, its clinical manifestations, and MR findings including the locations of lesions, the presence or absence of contrast enhancement, and the changes seen at follow-up MRI. Of the 22 patients, 13 had eclampsia (six during pregnancy and seven during puerperium). Four were receiving immunosuppressive therapy (three, cyclosporine ; one, FK 506). Four suffered renal failure and one had complicated migraine. The clinical manifestations included headache (n=12), visual disturbance (n=13), seizure (n=15), focal neurologic sign (n=3), and altered mental status (n=2). Fifteen patients had hypertension and the others normotension. MRI revealed that lesions were bilateral (n=20) or unilateral (n=2). In all patients the lesion was found in the cortical and subcortical areas of the parieto-occipital lobes ; other locations were the basal ganglia (n=9), posterior temporal lobe (n=8), frontal lobe (n=5), cerebellum (n=5), pons (n=2), and thalamus (n=1). All lesions were of high signal intensity on T2-weighted images, and of iso to low intensity on T1-weighted images. One was combined with acute hematoma in the left basal ganglia. In eight of 11 patients who underwent postcontrast T1-weighted MRI, there was no definite enhancement ; in one, enhancement was mild, and in tow, patchy. CT studies showed low attenuation, and MRA revealed mild vasospasm. The symptoms of all patients improved. Follow-up MRI in nine of 11 patients depicted complete resolution of the lesions ; in two, small infarctions remained but the extent of the lesions had decreased. Reversible posterior

  15. Reversed field pinches

    Energy Technology Data Exchange (ETDEWEB)

    Bodin, H.A.B. (Euratom/UKAEA Fusion Association, Abingdon (UK). Culham Lab.)

    1983-03-15

    The present status of RFP research is reviewed with emphasis on recent experimental developments. The basic properties of the RFP are summarised in section 2 including equilibrium and relaxed states, self-reversal and stability. The remainder of the paper deals with experimental results. There are five intermediate sized machines operating with the minor radii of the metal bellows liner in the range 9-26 cm, peak currents of a few hundred kA reached in between 0.1 and 4 ms with pulse lengths of up to more than 10 ms. The field configuration is set up using self-reversal usually assisted by slow Bsub(PHI) control. The temperatures are typically a few hundred eV (maximum approx.=600 eV on TPE-IR(M) in Japan) and the density is typically 10/sup 13/-10/sup 14/ cm/sup -3/ with maximum ..beta..sub(THETA)> or approx.10%. It is found that some plasma properties depend on the value of I/N (I is the current and N the line density) with a clear high-density limit due to radiation. The electron temperature increases with current; much of the data fits a dependence T..cap alpha..Isup(n) where 0.5reversed field pinch research will be highlighted with an indication of future trends in this work.

  16. Partial Reversible Gates(PRG) for Reversible BCD Arithmetic

    OpenAIRE

    Thapliyal, Himanshu; Arabnia, Hamid R; Bajpai, Rajnish; Sharma, Kamal K

    2007-01-01

    IEEE 754r is the ongoing revision to the IEEE 754 floating point standard and a major enhancement to the standard is the addition of decimal format. Furthermore, in the recent years reversible logic has emerged as a promising computing paradigm having its applications in low power CMOS, quantum computing, nanotechnology, and optical computing. The major goal in reversible logic is to minimize the number of reversible gates and garbage outputs. Thus, this paper proposes the novel concept of pa...

  17. Multiple stimulus reversible hydrogels

    Science.gov (United States)

    Gutowska, Anna; Krzyminski, Karol J.

    2006-04-25

    A polymeric solution capable of gelling upon exposure to a critical minimum value of a plurality of environmental stimuli is disclosed. The polymeric solution may be an aqueous solution utilized in vivo and capable of having the gelation reversed if at least one of the stimuli fall below, or outside the range of, the critical minimum value. The aqueous polymeric solution can be used either in industrial or pharmaceutical environments. In the medical environment, the aqueous polymeric solution is provided with either a chemical or radioisotopic therapeutic agent for delivery to a specific body part. The primary advantage of the process is that exposure to one environmental stimuli alone will not cause gelation, thereby enabling the therapeutic agent to be conducted through the body for relatively long distances without gelation occurring.

  18. Reverse photoacoustic standoff spectroscopy

    Science.gov (United States)

    Van Neste, Charles W.; Senesac, Lawrence R.; Thundat, Thomas G.

    2011-04-12

    A system and method are disclosed for generating a reversed photoacoustic spectrum at a greater distance. A source may emit a beam to a target and a detector measures signals generated as a result of the beam being emitted on the target. By emitting a chopped/pulsed light beam to the target, it may be possible to determine the target's optical absorbance by monitoring the intensity of light collected at the detector at different wavelengths. As the wavelength of light is changed, the target may absorb or reject each optical frequency. Rejection may increase the intensity at the sensing element and absorption may decrease the intensity. Accordingly, an identifying spectrum of the target may be made with the intensity variation of the detector as a function of illuminating wavelength.

  19. A Reversible Processor Architecture and its Reversible Logic Design

    DEFF Research Database (Denmark)

    Thomsen, Michael Kirkedal; Axelsen, Holger Bock; Glück, Robert

    2012-01-01

    We describe the design of a purely reversible computing architecture, Bob, and its instruction set, BobISA. The special features of the design include a simple, yet expressive, locally-invertible instruction set, and fully reversible control logic and address calculation. We have designed...... an architecture with an ISA that is expressive enough to serve as the target for a compiler from a high-level structured reversible programming language. All-in-all, this paper demonstrates that the design of a complete reversible computing architecture is possible and can serve as the core of a programmable...

  20. Effects of residual scale inhibitors on the performance of reverse osmosis membrane in blow-down water from circulating water system%循环水排污水中残余阻垢剂对反渗透膜性能的影响

    Institute of Scientific and Technical Information of China (English)

    杨伟; 刘芳; 高雅; 闫茜; 张利

    2015-01-01

    循环水排污水中残余的阻垢剂会导致其水质的变化,从而影响反渗透膜性能。本文以循环水中常用的阻垢剂聚天冬氨酸(PASP)、羟基亚乙基=膦酸(HEDP)和氨基三亚甲基膦酸(ATMP)为研究对象,首先考察了它们的阻垢性能,然后在此基础上,通过静态浸泡试验和动态试验考察了它们的存在对反渗透膜性能的影响。研究结果表明,PASP、HEDP和ATMP中,PASP的阻垢性能最优,阻垢率高达84.21%,三者均会对反渗透膜的表面结构、组成成分、膜通量以及脱盐率产生一定的影响。当PASP、HEDP和ATMP的浓度分别为50mg/L、10mg/L和30mg/L时,在反渗透系统连续运行10h后,膜通量分别下降5.53%、4.89%和9.09%,小于空白时的18.95%;此外,脱盐率有不同程度的提高。%Residual scale inhibitors can cause water quality changes in circulating cooling process,thus affect the performances of reverse osmosis membrane. This study investigated the scale inhibition performance of scale inhibitors,PASP,HEDP and ATMP. The effects on the performance of reverse osmosis membrane were investigated by static test and dynamic test. Results showed that among PASP,HEDP and ATMP,the scale inhibition performances of PASP were best and scale inhibition rate could be as high as 84.21%. All the three materials had certain effects on the surface of the reverse osmosis membrane structure,composition and membrane flux. When the concentration of PASP, HEDP and ATMP was 50mg/L,10mg/L and 30mg/L respectively,the membrane flux decreased by 5.53%,4.89%,9.09%,less than 18.95% of the blank solution. In addition,desalination rates increased.

  1. An Algebra of Reversible Quantum Computing

    OpenAIRE

    Wang, Yong

    2015-01-01

    Based on the axiomatization of reversible computing RACP, we generalize it to quantum reversible computing which is called qRACP. By use of the framework of quantum configuration, we show that structural reversibility and quantum state reversibility must be satisfied simultaneously in quantum reversible computation. RACP and qRACP has the same axiomatization modulo the so-called quantum forward-reverse bisimularity, that is, classical reversible computing and quantum reversible computing are ...

  2. Defining the Polar Field Reversal

    Science.gov (United States)

    Upton, Lisa; Hathaway, David H.

    2013-01-01

    The polar fields on the Sun are directly related to solar cycle variability. Recently there has been interest in studying an important characteristic of the polar fields: the timing of the polar field reversals. However this characteristic has been poorly defined, mostly due to the limitations of early observations. In the past, the reversals have been calculated by averaging the flux above some latitude (i.e. 55deg or 75deg). Alternatively, the reversal could be defined by the time in which the previous polarity is completely canceled and replaced by the new polarity at 90de, precisely at the pole. We will use a surface flux transport model to illustrate the differences in the timing of the polar field reversal based on each of these definitions and propose standardization in the definition of the polar field reversal. The ability to predict the timing of the polar field reversal using a surface flux transport model will also be discussed.

  3. Company policy toward reverse logistics

    OpenAIRE

    Klapalová Alena; Králová Maria

    2012-01-01

    The paper deals with the results of questionnaire survey examining the character of companies’ policies towards management of reverse flows logistics, namely innovativeness of policy related to the reasons of involvement to manage reverse flows and to the planning system of reverse logistics. Answers from the informants and respondents from 150 Czech companies were analysed with the employment of statistical methods (frequencies, contingency tables and Man – Whitney test) to explore the poten...

  4. Geomagnetic Reversals during the Phanerozoic.

    Science.gov (United States)

    McElhinny, M W

    1971-04-01

    An antalysis of worldwide paleomagnetic measurements suggests a periodicity of 350 x 10(6) years in the polarity of the geomagnetic field. During the Mesozoic it is predominantly normal, whereas during the Upper Paleozoic it is predominantly reversed. Although geomagnetic reversals occur at different rates throughout the Phanerozoic, there appeaars to be no clear correlation between biological evolutionary rates and reversal frequency. PMID:17735224

  5. Magnetic reversals and mass extinctions

    Science.gov (United States)

    Raup, D. M.

    1985-01-01

    The results of a study of reversals of the earth's magnetic field over the past 165 Myr are presented. A stationary periodicity of 30 Myr emerges which predicts pulses of increased reversal activity centered at 10, 40, 70, . . . Myr before the present. The correlation between the reversal intensity and biological extinctions is examined, and a nontrivial discrepancy is found between the magnetic and extinction periodicity.

  6. Magnetic Reversal on Vicinal Surfaces

    OpenAIRE

    Hyman, R. A.; Zangwill, A.; Stiles, M. D.

    1998-01-01

    We present a theoretical study of in-plane magnetization reversal for vicinal ultrathin films using a one-dimensional micromagnetic model with nearest-neighbor exchange, four-fold anisotropy at all sites, and two-fold anisotropy at step edges. A detailed "phase diagram" is presented that catalogs the possible shapes of hysteresis loops and reversal mechanisms as a function of step anisotropy strength and vicinal terrace length. The steps generically nucleate magnetization reversal and pin the...

  7. Arsenic and Antimony Removal from Drinking Water by Point-of-Entry Reverse Osmosis Coupled with Dual Plumbing Distribution - U.S. EPA Demonstration Project at Carmel Elementary School in Carmel, ME -Final Performance Evaluation Report

    Science.gov (United States)

    This report documents the activities performed for and the results obtained from the arsenic and antimony removal treatment technology demonstration project at the Carmel Elementary School (CES) in Carmel, ME. An innovative approach of employing point of entry (POE) reverse osmo...

  8. Initiation of HIV Reverse Transcription

    Directory of Open Access Journals (Sweden)

    Roland Marquet

    2010-01-01

    Full Text Available Reverse transcription of retroviral genomes into double stranded DNA is a key event for viral replication. The very first stage of HIV reverse transcription, the initiation step, involves viral and cellular partners that are selectively packaged into the viral particle, leading to an RNA/protein complex with very specific structural and functional features, some of which being, in the case of HIV-1, linked to particular isolates. Recent understanding of the tight spatio-temporal regulation of reverse transcription and its importance for viral infectivity further points toward reverse transcription and potentially its initiation step as an important drug target.

  9. Reversal of underground mine ventilation

    Energy Technology Data Exchange (ETDEWEB)

    Ray, S.K.; Sahay, N.; Singh, R.P.; Singh, A.K.; Bhowmick, B.C. [Central Mining Research Institute, Dhanbad (India)

    2002-09-01

    Reversal of main ventilation is one of the important means to isolate a fire during emergency. In America, it has been reported that by fan reversal lives have been saved in underground coal mines. Indian coal mines have so far not come forward to adopt this method. Not much research work has so far been carried out in India. This paper deals with international review of the work carried out in other countries. Laws relating to the reversal of ventilation in different countries of the world is discussed. The effect of reversal on goaf gases and adjustment of ventilation flow is also outlined. 17 refs., 1 fig., 2 tabs.

  10. REVERSE LOGISTICS OF ELECTRONICS WASTE

    Directory of Open Access Journals (Sweden)

    ADRIANO NICOLAU SELPIS

    2012-07-01

    Full Text Available The growing demand for electronics equipment, its fast obsolescence, lack of oversight and legislation of its final destination, has contributed them to be discarted in common junk. Electronic equipments and their parts such as computers, TVs, cell phones, refrigerators, batteries, among others, contains highly toxic heavy metals such as mercury, cadmium, arsenic, copper, lead, and others, that if they are burned, pollute the air, besides being potential risk to the health of the garbage collectors, and also, when being in contact with the ground, they can pollute the water table, plants, animals, and consequently affect the human health. Based on research conducted by the analytical-descriptive method, we tried to link the the main threats to the environment and health that the incorrect disposal of waste electronics may represent, as well as identify and present some actions to minimize this impact. It was concluded that the main factors that contribute to the indiscriminate disposal of waste electronics are the lack of legislation to responsibility the manufacturers, strict supervision, tax incentives for the practice of reverse logistics, technology for sophisticated components recycling and environmental education.

  11. Design of Reversible Sequential Circuit Using Reversible Logic Synthesis

    Directory of Open Access Journals (Sweden)

    Md. Mosharof Hossin

    2012-01-01

    Full Text Available Reversible logic is one of the most vital issue at present time and it has different areas for its application, those are low power CMOS, quantum computing, nanotechnology, cryptography, optical computing, DNA computing, digital signal processing (DSP, quantum dot cellular automata, communication, computer graphics. It is not possible to realize quantum computing without implementation of reversible logic. The main purposes of designing reversible logic are to decrease quantum cost, depth of the circuits and the number of garbage outputs. In this paper, we have proposed a new reversible gate. And we have designedRS flip flop and D flip flop by using our proposed gate and Peres gate. The proposed designs are better than the existing proposed ones in terms of number of reversible gates and garbage outputs. So, this realization is more efficient and less costly than other realizations.

  12. Design of Reversible Sequential Circuit Using Reversible Logic Synthesis

    Directory of Open Access Journals (Sweden)

    Md. Belayet Ali

    2011-12-01

    Full Text Available Reversible logic is one of the most vital issue at present time and it has different areas for its application,those are low power CMOS, quantum computing, nanotechnology, cryptography, optical computing, DNA computing, digital signal processing (DSP, quantum dot cellular auto meta, communication, computer graphics. It is not possible to realize quantum computing without implementation of reversible logic. The main purposes of designing reversible logic are to decrease quantum cost, depth of the circuits and the number of garbage outputs. In this paper, we have proposed a new reversible gate. And we have designed RS flip flop and D flip flop by using our proposed gate and Peres gate. The proposed designs are better than the existing proposed ones in terms of number of reversible gates and garbage outputs. So, this realization is more efficient and less costly than other realizations.

  13. Time reversal and holography with spacetime transformations

    Science.gov (United States)

    Bacot, Vincent; Labousse, Matthieu; Eddi, Antonin; Fink, Mathias; Fort, Emmanuel

    2016-10-01

    Wave control is usually performed by spatially engineering the properties of a medium. Because time and space play similar roles in wave propagation, manipulating time boundaries provides a complementary approach. Here, we experimentally demonstrate the relevance of this concept by introducing instantaneous time mirrors. We show with water waves that a sudden change of the effective gravity generates time-reversed waves that refocus at the source. We generalize this concept for all kinds of waves, introducing a universal framework which explains the effect of any time disruption on wave propagation. We show that sudden changes of the medium properties generate instant wave sources that emerge instantaneously from the entire space at the time disruption. The time-reversed waves originate from these `Cauchy sources’, which are the counterpart of Huygens virtual sources on a time boundary. It allows us to revisit the holographic method and introduce a new approach for wave control.

  14. Field reversal experiments (FRX)

    International Nuclear Information System (INIS)

    The equilibrium, confinement, and stability properties of the reversed-field configuration (RFC) are being studied in two theta-pinch facilities. The RFC is an elongated toroidal plasma confined in a purely poloidal field geometry. The open field lines of the linear theta pinch support the closed-field RFC much like the vertical field centers the toroidal plasma in a tokamak. Depending on stability and confinement properties, the RFC might be used to greatly reduce the axial losses in linear fusion devices such as mirrors, theta pinches, and liners. The FRX systems produce RFC's with a major radius R = 2-6 cm, minor radius a approximately 2 cm, and a total length l approximately 35 cm. The observed temperatures are T/sub e/ approximately 100 eV and T/sub i/ = 150-350 eV with a peak density n approximately 2 x 1015 cm-3. After the plasma reaches equilibrium, the RFC remains stable for up to 30 μs followed by the rapid growth of the rotational m = 2 instability, which terminates the confinement. During the stable equilibrium, the particle and energy confinement times are more than 10 times longer than in an open-field system. The behavior of the m = 2 mode qualitatively agrees with the theoretically predicted instability for rotational velocities exceeding some critical value

  15. Driving forward in reverse

    International Nuclear Information System (INIS)

    We describe the use of TILLING in Lotus japonicus and the development of deletion (De)-TILLING in Medicago truncatula. The evolution of RevGenUK has been driven by the development of reverse genetics technologies in these two model legumes and Brassica rapa, which functions as a translational species for brassica crops. TILLING and De-TILLING, are underpinned by populations of plants mutagenised with either EMS (that causes point mutations) or fast neutrons (that cause deletions) respectively. They permit the isolation of either allelic series of mutants or knockouts. Mutation detection will be developed from a number of independent gel-based systems to be carried out on a single platform - capillary electrophoresis. We are currently TILLING in both model legumes, but these developments will be applied to all three species. The resource will develop an open source database-driven system to support laboratory information management, analysis and the cataloguing of mutants in a genome context across all the species. (author)

  16. Driving Forward in Reverse

    International Nuclear Information System (INIS)

    We describe the use of TILLING in Lotus japonicus and the development of deletion (De)-TILLING in Medicago truncatula. The evolution of RevGen UK has been driven by the development of reverse genetics technologies in these two model legumes and Brassica rapa, which functions as a translational species for brassica crops. TILLING and De-TILLING are underpinned by populations of plants mutagenized with either EMS (that causes point mutations) or fast neutrons (that cause deletions), respectively. They permit the isolation of either allelic series of mutants or knockouts. Mutation detection will be developed from a number of independent gel-based systems to be carried out on a single platform - capillary electrophoresis. We are currently TILLING in both model legumes, but these developments will be applied to all three species. The resource will develop an open source database-driven system to support laboratory information management, analysis and the cataloguing of mutants in a genome context across all the species. (author)

  17. Time Reversal Violation

    Energy Technology Data Exchange (ETDEWEB)

    Quinn, H; /SLAC

    2009-01-27

    This talk briefly reviews three types of time-asymmetry in physics, which I classify as universal, macroscopic and microscopic. Most of the talk is focused on the latter, namely the violation of T-reversal invariance in particle physics theories. In sum tests of microscopic T-invariance, or observations of its violation, are limited by the fact that, while we can measure many processes, only in very few cases can we construct a matched pair of process and inverse process and observe it with sufficient sensitivity to make a test. In both the cases discussed here we can achieve an observable T violation making use of flavor tagging, and in the second case also using the quantum properties of an antisymmetric coherent state of two B mesons to construct a CP-tag. Both these tagging properties depend only on very general properties of the flavor and/or CP quantum numbers and so provide model independent tests for T-invariance violations. The microscopic laws of physics are very close to T-symmetric. There are small effects that give CP- and T-violating processes in three-generation-probing weak decays. Where a T-violating observable can be constructed we see the relationships between T-violation and CP-violation expected in a CPT conserving theory. These microscopic effects are unrelated to the 'arrow of time' that is defined by increasing entropy, or in the time direction defined by the expansion of our Universe.

  18. Biocatalysis in water-in-ionic liquid microemulsions: a case study with horseradish peroxidase.

    Science.gov (United States)

    Moniruzzaman, M; Kamiya, N; Goto, M

    2009-01-20

    In this article we report the first results on the enzymatic activity of horseradish peroxidase (HRP) microencapsulated in water-in-ionic liquid (w/IL) microemulsions using pyrogallol as the substrate. Toward this goal, the system used in this study was composed of anionic surfactant AOT (sodium bis(2-ethyl-1-hexyl)sulfosuccinate)/hydrophobic IL [C(8)mim][Tf(2)N] (1-octyl-3-methyl imidazolium bis(trifluoromethylsulfonyl)amide)/water/1-hexanol. In this system, the catalytic activity of HRP was measured as a function of substrate concentrations, W(0) (molar ratio of water to surfactant), pH, and 1-hexanol content. The curve of the activity-W(0) profile was found to be hyperbolic for the new microemulsion. The apparent Michaelis-Menten kinetic parameters (k(cat) and K(m)) were estimated and compared to those obtained from a conventional microemulsion. Apparently, it was found that HRP-catalyzed oxidation of pyrogallol by hydrogen peroxide in IL microemulsuions is much more effective than in a conventional AOT/water/isooctane microemulsion. The stability of HRP solubilized in the newly developed w/IL microemulsions was examined, and it was found that HRP retained almost 70% of its initial activity after incubation at 28 degrees C for 30 h. PMID:19113810

  19. Enzyme recovery using reversed micelles.

    NARCIS (Netherlands)

    Dekker, M.

    1990-01-01

    The objective of this study was to develop a liquid-liquid extraction process for the recovery of extracellular enzymes. The potentials of reaching this goal by using reversed micelles in an organic solvent have been investigated.Reversed micelles are aggregates of surfactant molecules containing an

  20. Towards a Reversible Functional Language

    DEFF Research Database (Denmark)

    Yokoyama, Tetsuo; Axelsen, Holger Bock; Glück, Robert

    2011-01-01

    We identify concepts of reversibility for a functional language by means of a set of semantic rules with specific properties. These properties include injectivity along with local backward determinism, an important operational property for an efficient reversible language. We define a concise rev...

  1. A novel hybrid process of reverse electrodialysis and reverse osmosis for low energy seawater desalination and brine management

    OpenAIRE

    Li, Y.; Krantz, B; Cornelissen, R; Post, W.; Verliefde, A.R.D.; Tang, Y.

    2013-01-01

    This paper introduces a novel concept for a hybrid desalination system that combines reverse electrodialysis (RED) and reverse osmosis (RO) processes. In this hybrid process the RED unit harvests the energy in the form of electricity from the salinity gradient between a highly concentrated solution (e.g., seawater or concentrated brine) and a low salinity solution (e.g., biologically treated secondary effluent or impaired water). The RED-treated high salinity solution has a lower salt concent...

  2. AOT微乳液中通过水化电子产额调控合成BaSO4纳米纤维%Synthesis of BaSO4 Nanofibers Controlled by the Yield of Hydrated Electrons in AOT-Based Microemulsions

    Institute of Scientific and Technical Information of China (English)

    徐文丽; 陈庆德; 沈兴海

    2014-01-01

    Single-crystal BaSO4 nanofibers and multi-architecture bundles were successful y synthesized in sodium bis(2-ethylhexyl) sulfosuccinate (AOT)-based microemulsions containing K2S2O8 and BaCl2, in which the control ed release of SO24-ions was realized in situ by the radiolytic reduction of S2O28-ions. The molar ratio of water to surfactant (ωvalues), the counterions of Ba2+, and the addition of aromatic compounds into the oil phase of the microemulsions were used to adjust the yield of hydrated electrons (e-aq). This al owed for control ing the reduction of S2O28- ions and the release of SO24- ions, leading to the shape manipulation of BaSO4 nanoparticle. With an increase inωvalues or dose rate, the yield of e-aq increased, which led to a quicker release of SO24-ions, and this did not favor the formation of BaSO4 nanofibers. When BaCl2 was replaced with Ba(NO3)2 the formation of nanofilaments became possible at a higher dose rate and a higherωvalue, because NO3-effectively decreased the yield of e-aq and the rate of S2O28-ion reduction. When toluene was added into the oil phase of the microemulsions, the excess electrons were effectively scavenged in the oil phase, and the concentration of e-aq in the water pool decreased. This favored the formation of nanofibers at higher dose rates. These results showed that the mechanism about morphology control by the yield of e-aq was verified in the syntheses of BaSO4 nanoparticle.%通过γ-辐照含有K2S2O8和BaCl2的二(2-乙基己基)琥珀酸酯磺酸钠(AOT)反相微乳液,将S2O28-通过辐射还原实现了SO24-的原位缓释,从而成功制备出BaSO4纳米纤维单晶,并进一步制得多层次的纳米纤维束结构。在此基础上,通过改变水与表面活性剂物质的量之比(ω值)、改变钡盐阴离子和在微乳液连续相添加芳香化合物等手段来调节水化电子(e-aq)产额,控制微乳液水池中S2O28-的还原和SO24-的缓释速率,成功实现了对BaSO4纳米粒子

  3. A Typology of Reverse Innovation

    DEFF Research Database (Denmark)

    von Zedtwitz, Max; Corsi, Simone; Søberg, Peder Veng;

    2015-01-01

    secondary market introduction, this study expands the espoused definition of reverse innovation beyond its market-introduction focus with reversals in the flow of innovation in the ideation and product development phases. Recognizing that each phase can take place in different geographical locations......Reverse innovation commonly refers to an innovation initially launched in a developing country and later introduced to an advanced country. Adopting a linear innovation model with the four sequential phases of concept ideation, product development, primary target market introduction, and subsequent......, the paper then introduces a typology of global innovation with 16 different types of innovation flows between advanced and emerging countries, 10 of which are reverse innovation flows. The latter are further differentiated into weak and strong reverse innovation, depending on the number of innovation phases...

  4. Reversed polarity patches at the CMB and geomagnetic field reversal

    Institute of Scientific and Technical Information of China (English)

    XU; Wenyao(徐文耀); WEI; Zigang(魏自刚)

    2002-01-01

    The International Geomagnetic Reference Field models (IGRF) for 1900-2000 are used to calculate the geomagnetic field distribution in the Earth' interior from the ground surface to the core-mantle boundary (CMB) under the assumption of insulated mantle. Four reversed polarity patches, as one of the most important features of the CMB field, are revealed. Two patches with +Z polarity (downward) at the southern African and the southern American regions stand out against the background of -Z polarity (upward) in the southern hemisphere, and two patches of -Z polarity at the North Polar and the northern Pacific regions stand out against the +Z background in the northern hemisphere. During the 1900-2000 period the southern African (SAF) patch has quickly drifted westward at a speed of 0.2-0.3°/a; meanwhile its area has expanded 5 times, and the magnetic flux crossing the area has intensified 30 times. On the other hand, other three patches show little if any change during this 100-year period. Extending upward, each of the reversed polarity patches at the CMB forms a chimney-shaped "reversed polarity column" in the mantle with the bottom at the CMB. The height of the SAF column has grown rapidly from 200km in 1900 to 900km in 2000. If the column grows steadily at the same rate in the future, its top will reach to the ground surface in 600-700 years. And then a reversed polarity patch will be observed at the Earth's surface, which will be an indicator of the beginning of a magnetic field reversal. On the basis of this study, one can describe the process of a geomagnetic polarity reversal, the polarity reversal may be observed firstly in one or several local regions; then the areas of these regions expand, and at the same time, other new reversed polarity regions may appear. Thus several poles may exist during a polarity reversal.

  5. Reversible computing and cellular automata - A survey

    OpenAIRE

    Morita, Kenichi

    2008-01-01

    Reversible computing is a paradigm where computing models are defined so that they reflect physical reversibility, one of the fundamental microscopic physical property of Nature. In this survey/tutorial paper, we discuss how computation can be carried out in a reversible system, how a universal reversible computer can be constructed by reversible logic elements, and how such logic elements are related to reversible physical phenomena. We shall see that, in reversible systems, computation can ...

  6. 普通反渗透复合膜处理高含盐量高硬度苦咸水实验研究%Experimental Study on Processing Blackish Water with High Salinity and High Hardness by Ordinary Reverse Osmosis Composite Membrane

    Institute of Scientific and Technical Information of China (English)

    李旭; 武福平

    2011-01-01

    According to the characteristics of groundwater with high hardness and salinity along Nanjiang railway,desalination experiments of blackish water were carried out by using BW30. 4040 ordinary reverse osmosis membrane. The effects of the desalination tine and the temperature of blackish water as well as the pressure on the separation performance and stability of reverse osmosis membrane were investigated. The best operation parameter has been determined,namely,recovery rate is 40~60%, operating pressure is 1. 3 ~1. 6 Mpa and temperature is 10~25 ℃. The results show that it is reasonable and effective to desalinate the high concentration blackish water with ordinary reverse osmosis composite membrane.%针对南疆铁路沿线地下水极高硬度及含盐量的水质特征,实验考察了采用普通反渗透复合膜处理其水质的可行性,考察了该膜的分离性能随操作压力、温度、运行时间等变化的影响及膜的运行稳定性,确定了最佳运行条件,即:回收率为:40%~60%,操作压力1.3~1.6 MPa,温度10~25℃.结果表明:采用普通反渗透复合膜来处理高含盐量高硬度苦咸水是可行的也是有效的.

  7. Boron Removal in Seawater Reverse Osmosis System

    KAUST Repository

    Rahmawati, Karina

    2011-07-01

    Reverse osmosis successfully proves to remove more than 99% of solute in seawater, providing fresh water supply with satisfied quality. Due to some operational constraints, however, some trace contaminants removal, such as boron, cannot be achieved in one pass system. The stringent criterion for boron from World Health Organization (WHO) and Saudi Arabia local standard (0.5 mg/l) is hardly fulfilled by single pass sea water reverse osmosis (SWRO) plants. Some design processes have been proposed to deal with boron removal, but they are not economically efficient due to high energy and chemical consumption. The objective of this study was to study boron removal by different reverse osmosis membranes in two pH conditions, with and without antiscalant addition. Thus, it was expected to observe the possibility of operating single pass system and necessity to operate two pass system using low energy membrane. Five membrane samples were obtained from two different manufacturers. Three types of feed water pH were used, pH 8, pH 10, and pH 10 with antiscalant addition. Experiment was conducted in parallel to compare membrane performance from two manufacturers. Filtration was run with fully recycle mode for three days. Sample of permeate and feed were taken every 12 hours, and analyzed for their boron and TDS concentration. Membrane samples were also tested for their surface charge. The results showed that boron rejection increases as the feed pH increases. This was caused by dissociation of boric acid to negatively charged borate ion and more negatively charged membrane surface at elevated pH which enhance boron rejection. This study found that single pass reverse osmosis system, with and without elevating the pH, may not be possible to be applied because of two reasons. First, permeate quality in term of boron, does not fulfill WHO and local Saudi Arabia regulations. Second, severe scaling occurs due to operation in alkaline condition, since Ca and Mg concentration are

  8. Development of reversible strain gage

    International Nuclear Information System (INIS)

    A high-temperature strain gage which can be peeled after taking required apparent strain measurements in a furnace and can be attached reverse-side-up at the point of interest on a test structure was developed. Using the ''reversible'' strain gage with selected room-temperature curing type polyester adhesive, one can expect to measure thermal strain accurately, especially for on large structures, at the first test in temperature up to 250 deg C. The repeatability of apparent strains for about 100 reversible gages was within 50 microstrains of difference at 250 deg C (within 30 microstrains of difference for 80 % of the test gages). (author)

  9. Reversal of the CD4(+)/CD8(+) T-cell ratio in lymph node cells upon in vitro mitogenic stimulation by highly purified, water-soluble S3-S4 dimer of pertussis toxin.

    Science.gov (United States)

    Latif, R; Kerlero de Rosbo, N; Amarant, T; Rappuoli, R; Sappler, G; Ben-Nun, A

    2001-05-01

    Pertussis toxin (PT), a holomer consisting of a catalytic S1 subunit and a B oligomer composed of S2-S4 and S3-S4 dimers, held together by the S5 subunit, exerts profound effects on immune cells, including T-cell mitogenicity. While the mitogenic activity of PT was shown to reside fully within the B oligomer, it could not be assigned to any particular B-oligomer component. In this study, we purified the S3-S4 dimer to homogeneity under conditions propitious to maintenance of the native conformation. In contrast to previous reports which suggested that both S3-S4 and S2-S4 dimers are necessary for mitogenic activity, our preparation of the highly purified S3-S4 dimer was as strongly mitogenic as the B oligomer, suggesting that the S3-S4 dimer accounts for the mitogenic activity of the B oligomer. Moreover, in vitro stimulation of naive lymphocytes by the S3-S4 dimer resulted in reversal of the normal CD4(+)/CD8(+) T-cell ratio from approximately 2:1 to 1:2. The reversal of the CD4(+)/CD8(+) T-cell ratio is unlikely to be due to preferential apoptosis-necrosis of CD4(+) T cells, as indicated by fluorescence-activated cell sorter analysis of annexin-stained T-cell subsets, or to preferential stimulation of CD8(+) T cells. The mechanism underlying the reversal requires further investigation. Nevertheless, the data presented indicate that the S3-S4 dimer may have potential use in the context of diseases amenable to immunological modulation.

  10. What Do Reversible Programs Compute?

    DEFF Research Database (Denmark)

    Axelsen, Holger Bock; Glück, Robert

    2011-01-01

    Reversible computing is the study of computation models that exhibit both forward and backward determinism. Understanding the fundamental properties of such models is not only relevant for reversible programming, but has also been found important in other fields, e.g., bidirectional model...... be the starting point of a computational theory of reversible computing. We provide a novel semantics-based approach to such a theory, using reversible Turing machines (RTMs) as the underlying computation model. We show that the RTMs can compute exactly all injective, computable functions. We find that the RTMs...... are not strictly classically universal, but that they support another notion of universality; we call this RTM-universality. Thus, even though the RTMs are sub-universal in the classical sense, they are powerful enough as to include a self-interpreter. Lifting this to other computation models, we propose r...

  11. Reverse Engineering Quantum Field Theory

    CERN Document Server

    Oeckl, Robert

    2012-01-01

    An approach to the foundations of quantum theory is advertised that proceeds by "reverse engineering" quantum field theory. As a concrete instance of this approach, the general boundary formulation of quantum theory is outlined.

  12. Reverse engineering quantum field theory

    Science.gov (United States)

    Oeckl, Robert

    2012-12-01

    An approach to the foundations of quantum theory is advertised that proceeds by "reverse engineering" quantum field theory. As a concrete instance of this approach, the general boundary formulation of quantum theory is outlined.

  13. An Overview of Reverse Logistics

    Institute of Scientific and Technical Information of China (English)

    WANG Jia-xiang; HE Xin

    2005-01-01

    Until recently, investment in logistics has focused mainly on the flows from companies to markets. Growing concerns for the environment and conserving resources have created new logistical approaches to more effectively manage the distribution function, and make better use of the resources available to an organization. One such approach is reverse logistics, which uses various methods to give scope for a back-load of finished products, components, waste, reusable packing, etc. from consumer to manufacturer. Back-loads allow manufacturers to reduce costs by using the distribution vehicle's return journey to create income or added value. This basic concept is now being developed to create novel solutions to the problems of reducing pollution, costs and vehicle movements, whilst maintaining high customer service levels. In this paper, the idea of reverse logistics is presented; motivations for it are analyzed, several successful practices are demonstrated and some important truths regarding successful reverse logistics are identified, trend of reverse logistics is provided.

  14. Designing the Reverse Supply Chain

    DEFF Research Database (Denmark)

    Gobbi, Chiara

    2011-01-01

    for the reverse supply chain. Design/methodology/approach – In order to identify the relevance of the Fisher model, the model needs to be recast in terms of PRV, which, in this context, is considered the independent variable in the reverse logistics arena. Products defined as innovative in Fisher's taxonomy......Purpose – The purpose of this paper is to explore the impact of the product residual value (PRV) and the loss of value over time of returned products in the reverse supply chain configuration. It also examines whether or not the distinction of Fisher's functional and innovative products holds...... correspond to disposed products with high residual value, whereas functional products correspond to disposed products with low residual value. Furthermore, the PRV and the speed at which returned products lose their value are considered in order to determine the configuration of the reverse supply chain...

  15. CEO Turnover in Reverse Splits

    OpenAIRE

    Li-Hsun Wang; Chu-Hsiung Lin; Hsien-Ming Chen

    2010-01-01

    This study examines the application of CEO turnover on reverse stock splits firms. Using Taiwanese samples, we find that non-CEO turnover firms receive negative long-term abnormal returns, and their financial performances continue to decline following reverse splits. These findings are consistent with prior studies. Contrarily, neither significantly negative long-term abnormal returns nor changes on financial performance were found for CEO turnover firms. This study concludes that applying CE...

  16. Laparoscopic reversal of Hartmann's procedure

    DEFF Research Database (Denmark)

    Svenningsen, Peter Olsen; Bulut, Orhan; Jess, Per

    2010-01-01

    A change in procedure from open to laparoscopic reversal of Hartmann's colostomy was implemented at our department between May 2005 and December 2008. The aim of the study was to investigate if this change was beneficial for the patients.......A change in procedure from open to laparoscopic reversal of Hartmann's colostomy was implemented at our department between May 2005 and December 2008. The aim of the study was to investigate if this change was beneficial for the patients....

  17. Deciphering records of geomagnetic reversals

    Science.gov (United States)

    Valet, Jean-Pierre; Fournier, Alexandre

    2016-06-01

    Polarity reversals of the geomagnetic field are a major feature of the Earth's dynamo. Questions remain regarding the dynamical processes that give rise to reversals and the properties of the geomagnetic field during a polarity transition. A large number of paleomagnetic reversal records have been acquired during the past 50 years in order to better constrain the structure and geometry of the transitional field. In addition, over the past two decades, numerical dynamo simulations have also provided insights into the reversal mechanism. Yet despite the large paleomagnetic database, controversial interpretations of records of the transitional field persist; they result from two characteristics inherent to all reversals, both of which are detrimental to an ambiguous analysis. On the one hand, the reversal process is rapid and requires adequate temporal resolution. On the other hand, weak field intensities during a reversal can affect the fidelity of magnetic recording in sedimentary records. This paper is aimed at reviewing critically the main reversal features derived from paleomagnetic records and at analyzing some of these features in light of numerical simulations. We discuss in detail the fidelity of the signal extracted from paleomagnetic records and pay special attention to their resolution with respect to the timing and mechanisms involved in the magnetization process. Records from marine sediments dominate the database. They give rise to transitional field models that often lead to overinterpret the data. Consequently, we attempt to separate robust results (and their subsequent interpretations) from those that do not stand on a strong observational footing. Finally, we discuss new avenues that should favor progress to better characterize and understand transitional field behavior.

  18. Vasectomy reversal: a clinical update

    OpenAIRE

    Patel, Abhishek P; Smith, Ryan P.

    2016-01-01

    textabstractVasectomy is a safe and effective method of contraception used by 42-60 million men worldwide. Approximately 3%-6% of men opt for a vasectomy reversal due to the death of a child or divorce and remarriage, change in financial situation, desire for more children within the same marriage, or to alleviate the dreaded postvasectomy pain syndrome. Unlike vasectomy, vasectomy reversal is a much more technically challenging procedure that is performed only by a minority of urologists and...

  19. Reversals of the solar dipole

    OpenAIRE

    Moss, David; Kitchatinov, Leonid L.; Sokoloff, Dmitri

    2012-01-01

    During a solar magnetic field reversal the magnetic dipole moment does not vanish, but migrates between poles, in contradiction to the predictions of mean-field dynamo theory. We try to explain this as a consequence of magnetic fluctuations. We exploit the statistics of fluctuations to estimate observable signatures. Simple statistical estimates, taken with results from mean-field dynamo theory, suggest that a non-zero dipole moment may persist through a global field reversal. Fluctuations in...

  20. Proceedings of the Interdisciplinary colloquium on reversibility

    International Nuclear Information System (INIS)

    This document contains the contributions to a colloquium, presented either in full text or as Power Point presentations. After an opening speech on decision reversibility of waste retrieval, the contributions respectively addressed: The charge taking ability, Proving and demonstrating reversibility, The issue of reversibility in an evolutional system in the case of CO2 geological disposal, Interactions between reversibility and disposal safety, Reversible disposal of radioactive wastes, Reversibility and retrievability within debates on decision-making about nuclear wastes in Finland and United Kingdom, The political qualities of technologies (irreversibility and reversibility in nuclear waste management), The contribution of economic analysis to the reversibility of nuclear waste disposal, The economic cost of reversibility, The appropriation of the notion of reversibility by the Andra, Arguments about the notion of reversibility, The notion of reversibility as a political symbol or actual concern, The project of document space 'ExploRe' (opened pluri-disciplinary exploration of reversibility), The participatory documentarisation at the service of reversibility. Posters addressed the following topics: Andra and reversibility, Reversibility, operational safety and long term safety in geological disposal, Andra's R and D in relationship the monitoring and survey of reversible disposal installations, Numerical simulation for the prediction and the analysis of disposal operation and aid-to-decision for its management, Demand of reversibility with respect to disposal progressive development, Taking reversibility into account for the complementarity between warehousing and storage

  1. Liquid-liquid extraction by reversed micelles in biotechnological processes

    Directory of Open Access Journals (Sweden)

    Kilikian B. V.

    2000-01-01

    Full Text Available In biotechnology there is a need for new purification and concentration processes for biologically active compounds such as proteins, enzymes, nucleic acids, or cells that combine a high selectivity and biocompatibility with an easy scale-up. A liquid-liquid extraction with a reversed micellar phase might serve these purposes owing to its capacity to solubilize specific biomolecules from dilute aqueous solutions such as fermentation and cell culture media. Reversed micelles are aggregates of surfactant molecules containing an inner core of water molecules, dispersed in a continuous organic solvent medium. These reversed micelles are capable of selectively solubilizing polar compounds in an apolar solvent. This review gives an overview of liquid-liquid extraction by reversed micelles for a better understanding of this process.

  2. Design of High speed Low Power Reversible Vedic multiplier and Reversible Divider

    OpenAIRE

    Srikanth G Department of Electronics & Communication Engineerig, Indur Institute of Engineering & Technology, Siddipet, Medak, JNTUH University, Telangana, India.; Nasam Sai Kumar

    2014-01-01

    This paper bring out a 32X32 bit reversible Vedic multiplier using "Urdhva Tiryakabhayam" sutra meaning vertical and crosswise, is designed using reversible logic gates, which is the first of its kind. Also in this paper we propose a new reversible unsigned division circuit. This circuit is designed using reversible components like reversible parallel adder, reversible left-shift register, reversible multiplexer, reversible n-bit register with parallel load line. The reversibl...

  3. Design of Reversible Random Access Memory

    OpenAIRE

    Mamun, Md. Selim Al; Hossain, Syed Monowar

    2013-01-01

    Reversible logic has become immensely popular research area and its applications have spread in various technologies for their low power consumption. In this paper we proposed an efficient design of random access memory using reversible logic. In the way of designing the reversible random access memory we proposed a reversible decoder and a write enable reversible master slave D flip-flop. All the reversible designs are superior in terms of quantum cost, delay and garbage outputs compared to ...

  4. A study on Reverse Osmosis Concentrated Water of Petrochemical Enterprises Treated by Zeolite Loading TiO2%沸石负载型TiO2处理炼化反渗透浓缩水的研究

    Institute of Scientific and Technical Information of China (English)

    李进辉; 丁慧; 张秀霞; 刘娜; 黄文升

    2013-01-01

    This paper studies zeolite loading titanium dioxide which is used to deal with reverse osmosis concentrated water of petrochemical enterprises. Besides it researches the performance of the catalyst on concentrated water and analyzes the factors which affect the degradation. The study shows that: the degradation rate of TOC in reverse osmosis titanium dioxide concentrated water can reach 67.4% and the best conditions of degradation are as follows: the pH value of 4 to 6, temperature of 30℃ to 40℃, illumination time of 2. 5 h, and catalyst dosage of 1. 5g/L. The experiment provides a new basis for the development of concentrated water treatment technology.%利用沸石负载型二氧化钛对炼化企业的反渗透浓缩水进行研究,考察了催化剂对浓缩水的处理效果及影响降解的因素.由实验结果可知:沸石负载型二氧化钛对反渗透浓缩水TOC降解率达到67.4%,降解浓缩水的最佳条件为.pH值为4~6,温度30~40℃,光照时间2.5h,催化剂投加量为1.5g/L.实验为浓缩水处理技术的发展提供了新的依据.

  5. A novel water-in-ionic liquid microemulsion and its interfacial effect on the activity of laccase.

    Science.gov (United States)

    Xue, Luyan; Qiu, Huajun; Li, Ying; Lu, Lu; Huang, Xirong; Qu, Yinbo

    2011-02-01

    It is of great significance to develop an appropriate water-in-ionic liquid (W/IL) microemulsion suitable for the expression of the catalytic activity of a given enzyme. In this paper, the phase diagram of a new AOT/Triton X-100/H(2)O/[Bmim][PF(6)] pseudo ternary system is presented. With the aid of nonionic surfactant Triton X-100, AOT could be dissolved in hydrophobic ionic liquid [Bmim][PF(6)], forming a large single phase microemulsion region. The water-in-[Bmim][PF(6)] (W/IL) microemulsion domain was identified electrochemically by using K(3)Fe(CN)(6) as a probe. The existence of W/IL microemulsions was demonstrated spectrophotometrically by using CoCl(2) as a probe. New evidences from the FTIR spectroscopic study, which was first introduced to the W/IL microemulsion by substituting D(2)O for H(2)O to eliminate the spectral interference, demonstrated that there existed bulk water at larger ω(0) values (ω(0) was defined as the molar ratio of water to the total surfactant) in the W/IL microemulsion, which had remained unclear before. In addition to the inorganic salts, biomacromolecule laccase could be solubilized in the W/IL microemulsion. The laccase hosted in the microemulsion exhibited a catalytic activity and the activity could be regulated by the composition of the interfacial membrane. PMID:20951007

  6. Reversals in nature and the nature of reversals

    CERN Document Server

    Stefani, F; Günther, U; Sorriso-Valvo, L; Xu, M; G\\"unther, Uwe; Gerbeth, Gunter; Sorriso-Valvo, Luca; Stefani, Frank; Xu, Mingtian

    2007-01-01

    The asymmetric shape of reversals of the Earth's magnetic field indicates a possible connection with relaxation oscillations as they were early discussed by van der Pol. A simple mean-field dynamo model with a spherically symmetric $\\alpha$ coefficient is analysed with view on this similarity, and a comparison of the time series and the phase space trajectories with those of paleomagnetic measurements is carried out. For highly supercritical dynamos a very good agreement with the data is achieved. Deviations of numerical reversal sequences from Poisson statistics are analysed and compared with paleomagnetic data. The role of the inner core is discussed in a spectral theoretical context and arguments and numerical evidence is compiled that the growth of the inner core might be important for the long term changes of the reversal rate and the occurrence of superchrons.

  7. Investigation on Single Phase Water Reverse Flow in Inverted U-Tubes of Steam Generator under Condition of Natural Circulation%自然循环蒸汽发生器倒U型管内单相流体倒流特性研究

    Institute of Scientific and Technical Information of China (English)

    王川; 于雷

    2011-01-01

    利用RELAP5/MOD3.3程序对某压水堆单相流体自然循环工况进行建模计算,给出了典型自然循环工况下蒸汽发生器(SG)倒U型传热管内正流和倒流的流最分布,分析了产生倒流现象的原因以及发生倒流的条件及判断依据.结果表明:SG倒U型管发生倒流的条件是SG出口腔压力高于入口腔压力;传热管内流体的提升压头不足以克服流动阻力压降.对于本文描述的核动力装置,在强迫循环转自然循环过程中,如果SG水位保持正常,则较短的倒U型传热管流量下滑更快且最终发生倒流.倒U型管内倒流流体温度分布均匀,与SG二次侧温度基本相同.%Using the code RELAP5/MOD3.3 to model and calculate the natural circulation of single-phase flow for the PWR, this paper provides the distribution of forward flow and reverse flow in the inverted U-tubes of the steam generator(SG) under some typical operating conditions in the natural circulation case, and analyzes the cause, occurrence condition and judgment principle of reverse flow phenomenon. The calculation results show that the occurrence conditions for reverse flow phenomenon are that the steam generator outlet pressure is higher than the inlet pressure and gravitational pressure drop is lower than the total of frictional pressure drop and area change pressure drop. As to the nuclear power plant described in this paper,if the water level of steam generator keeps normal, the mass flux of the shorter U-tubes will drop more quickly and reverse flow will occur. The temperature distributes uniformly in U-tubes with reverse flow and it is almost identical with that of SG in secondary side.

  8. Vasectomy reversal: a clinical update

    Directory of Open Access Journals (Sweden)

    Abhishek P Patel

    2016-01-01

    Full Text Available Vasectomy is a safe and effective method of contraception used by 42-60 million men worldwide. Approximately 3%-6% of men opt for a vasectomy reversal due to the death of a child or divorce and remarriage, change in financial situation, desire for more children within the same marriage, or to alleviate the dreaded postvasectomy pain syndrome. Unlike vasectomy, vasectomy reversal is a much more technically challenging procedure that is performed only by a minority of urologists and places a larger financial strain on the patient since it is usually not covered by insurance. Interest in this procedure has increased since the operating microscope became available in the 1970s, which consequently led to improved patency and pregnancy rates following the procedure. In this clinical update, we discuss patient evaluation, variables that may influence reversal success rates, factors to consider in choosing to perform vasovasostomy versus vasoepididymostomy, and the usefulness of vasectomy reversal to alleviate postvasectomy pain syndrome. We also review the use of robotics for vasectomy reversal and other novel techniques and instrumentation that have emerged in recent years to aid in the success of this surgery.

  9. Cylindrical air flow reversal barrier

    Energy Technology Data Exchange (ETDEWEB)

    Woznica, C.; Rodziewicz, M.

    1988-06-01

    Describes an innovative design introduced in the ZMP mine in Zory for quick reversal of ventilation air flow. Geologic mining conditions at the 705 m deep horizon, where the barrier was built, are described. According to the design used until now, a reversal system consisted of safety barriers, ventilation air locks, a ventilation bridge and stopping needed in case of a fire when air flow direction must be reversed. Nine air locks and an expensive concrete ventilation bridge were needed and the air locks had to be operated at 8 points of the region to effect reversal. The new design consists of a 2-storey cylindrical barrier which also fulfills the function of a ventilation bridge. It can be manually or remotely operated by a mechanical or pneumatic system. Tests showed that the new barrier permits immediate air flow reversal while retaining 60% of the original air, which is important in the case of fire and methane hazards. It permits improved seam panelling and splitting of pillars and brings an economy of about 40 million zlotys in construction cost. Design and operation of the barrier is illustrated and ventilation air circulation is explained. 7 figs.

  10. REVERSE LOGISTICS RETAIL LEVEL RETURN

    Directory of Open Access Journals (Sweden)

    Ivona Bajor

    2014-06-01

    Full Text Available Conducting scientific research regarding reverse logistics systems includes certain difficulties. Developed logistics systems are aimed at analysing reverse logistics issues and tend to continuously detect differences and oscillations in the flow of returned products and their characteristics. Developing logistics systems, as Croatian, find reverse logistics issues, regarding product returns, significantly complex and very often these issues are not observed as issues of priority. As distributive flow, reverse logistics systems fundaments should be also based on detailed analysis. Analysis in this flow presents amounts, reasons, process flows and quality of returned items. Because of complex product evaluation on individual level, reverse logistics procedures should be implemented as a methodology individually developed for every supply chain subject. This paper presents a research of retail level returns on the Croatian market, where the analysis implicated that the majority of products in return for this level is directed from final consumers and presents noncurrent inventories of distribution chain. The paper will present conducted research regarding characteristics of returns and routing these products from the retail level.

  11. Low Cost Reversible Signed Comparator

    Directory of Open Access Journals (Sweden)

    Farah Sharmin

    2013-10-01

    Full Text Available Nowadays exponential advancement in reversible comp utation has lead to better fabrication and integration process. It has become very popular ove r the last few years since reversible logic circuit s dramatically reduce energy loss. It consumes less p ower by recovering bit loss from its unique input-o utput mapping. This paper presents two new gates called RC-I and RC-II to design an n-bit signed binary comparator where simulation results show that the p roposed circuit works correctly and gives significa ntly better performance than the existing counterparts. An algorithm has been presented in this paper for constructing an optimized reversible n-bit signed c omparator circuit. Moreover some lower bounds have been proposed on the quantum cost, the numbers of g ates used and the number of garbage outputs generated for designing a low cost reversible sign ed comparator. The comparative study shows that the proposed design exhibits superior performance consi dering all the efficiency parameters of reversible logic design which includes number of gates used, quantum cost, garbage output and constant inputs. This proposed design has certainly outperformed all the other existing approaches.

  12. International overview of seawater desalination plant by reverse osmosis technology

    OpenAIRE

    Kangwen, Shu

    2012-01-01

    In a world faced with increased urbanization, population growth, climate change and degradation of water supplies, the importance of a reliable source of technology to provide fresh water emphasizes the importance of seawater desalination. Over the years a variety of seawater desalination methods have been developed throughout the world. The most common technologies available for desalination around the world are membrane reverse osmosis (RO), thermal distillation (TD) and electrodialysis ...

  13. Fault Testing for Reversible Circuits

    CERN Document Server

    Patel, K N; Markov, I L; Patel, Ketan N.; Hayes, John P.; Markov, Igor L.

    2004-01-01

    Applications of reversible circuits can be found in the fields of low-power computation, cryptography, communications, digital signal processing, and the emerging field of quantum computation. Furthermore, prototype circuits for low-power applications are already being fabricated in CMOS. Regardless of the eventual technology adopted, testing is sure to be an important component in any robust implementation. We consider the test set generation problem. Reversibility affects the testing problem in fundamental ways, making it significantly simpler than for the irreversible case. For example, we show that any test set that detects all single stuck-at faults in a reversible circuit also detects all multiple stuck-at faults. We present efficient test set constructions for the standard stuck-at fault model as well as the usually intractable cell-fault model. We also give a practical test set generation algorithm, based on an integer linear programming formulation, that yields test sets approximately half the size o...

  14. Ice ages and geomagnetic reversals

    Science.gov (United States)

    Wu, Patrick

    1992-01-01

    There have been speculations on the relationship between climatic cooling and polarity reversals of the earth's magnetic field during the Pleistocene. Two of the common criticisms on this relationship have been the reality of these short duration geomagnetic events and the accuracy of their dates. Champion et al. (1988) have reviewed recent progress in this area. They identified a total of 10 short-duration polarity events in the last 1 Ma and 6 of these events have been found in volcanic rocks, which also have K-Ar dates. Supposing that the speculated relationship between climatic cooling and geomagnetic reversals actually exist, two mechanisms that assume climatic cooling causes short period magnetic reversals will be investigated. These two methods are core-mantle boundary topography and transfer of the rotational energy to the core.

  15. Reverse Knowledge Transfer in MNEs

    DEFF Research Database (Denmark)

    Mudambi, Ram; Piscitello, Lucia; Rabbiosi, Larissa

    2014-01-01

    It is now well recognized that multinational enterprises (MNEs) are differentiated networks wherein subsidiaries vary in terms of their ability to create new knowledge and competencies for their parent groups. In much of this theory, it is taken for granted that subsidiary innovativeness has...... a positive correlation with the extent of reverse knowledge transfers to the parent MNE. Relying on the headquarters-subsidiary view of the MNE, we argue that, beyond a point, increasing subsidiary innovativeness will be associated with lower reverse knowledge transfers. Further, we argue...... that this relationship is sensitive to the subsidiary entry mode. Using data from a sample of 293 Italian subsidiaries, we find strong support for our hypotheses. In particular, our results confirm that the effect of subsidiary innovativeness on reverse knowledge transfers displays an inverted-U shape...

  16. Marburg Virus Reverse Genetics Systems

    Directory of Open Access Journals (Sweden)

    Kristina Maria Schmidt

    2016-06-01

    Full Text Available The highly pathogenic Marburg virus (MARV is a member of the Filoviridae family and belongs to the group of nonsegmented negative-strand RNA viruses. Reverse genetics systems established for MARV have been used to study various aspects of the viral replication cycle, analyze host responses, image viral infection, and screen for antivirals. This article provides an overview of the currently established MARV reverse genetic systems based on minigenomes, infectious virus-like particles and full-length clones, and the research that has been conducted using these systems.

  17. Reversible arithmetic logic unit for quantum arithmetic

    DEFF Research Database (Denmark)

    Thomsen, Michael Kirkedal; Glück, Robert; Axelsen, Holger Bock

    2010-01-01

    This communication presents the complete design of a reversible arithmetic logic unit (ALU) that can be part of a programmable reversible computing device such as a quantum computer. The presented ALU is garbage free and uses reversible updates to combine the standard reversible arithmetic...

  18. Role of Reverse Divalent Cation Diffusion in Forward Osmosis Biofouling.

    Science.gov (United States)

    Xie, Ming; Bar-Zeev, Edo; Hashmi, Sara M; Nghiem, Long D; Elimelech, Menachem

    2015-11-17

    We investigated the role of reverse divalent cation diffusion in forward osmosis (FO) biofouling. FO biofouling by Pseudomonas aeruginosa was simulated using pristine and chlorine-treated thin-film composite polyamide membranes with either MgCl2 or CaCl2 draw solution. We related FO biofouling behavior-water flux decline, biofilm architecture, and biofilm composition-to reverse cation diffusion. Experimental results demonstrated that reverse calcium diffusion led to significantly more severe water flux decline in comparison with reverse magnesium permeation. Unlike magnesium, reverse calcium permeation dramatically altered the biofilm architecture and composition, where extracellular polymeric substances (EPS) formed a thicker, denser, and more stable biofilm. We propose that FO biofouling was enhanced by complexation of calcium ions to bacterial EPS. This hypothesis was confirmed by dynamic and static light scattering measurements using extracted bacterial EPS with the addition of either MgCl2 or CaCl2 solution. We observed a dramatic increase in the hydrodynamic radius of bacterial EPS with the addition of CaCl2, but no change was observed after addition of MgCl2. Static light scattering revealed that the radius of gyration of bacterial EPS with addition of CaCl2 was 20 times larger than that with the addition of MgCl2. These observations were further confirmed by transmission electron microscopy imaging, where bacterial EPS in the presence of calcium ions was globular, while that with magnesium ions was rod-shaped.

  19. Role of Reverse Divalent Cation Diffusion in Forward Osmosis Biofouling.

    Science.gov (United States)

    Xie, Ming; Bar-Zeev, Edo; Hashmi, Sara M; Nghiem, Long D; Elimelech, Menachem

    2015-11-17

    We investigated the role of reverse divalent cation diffusion in forward osmosis (FO) biofouling. FO biofouling by Pseudomonas aeruginosa was simulated using pristine and chlorine-treated thin-film composite polyamide membranes with either MgCl2 or CaCl2 draw solution. We related FO biofouling behavior-water flux decline, biofilm architecture, and biofilm composition-to reverse cation diffusion. Experimental results demonstrated that reverse calcium diffusion led to significantly more severe water flux decline in comparison with reverse magnesium permeation. Unlike magnesium, reverse calcium permeation dramatically altered the biofilm architecture and composition, where extracellular polymeric substances (EPS) formed a thicker, denser, and more stable biofilm. We propose that FO biofouling was enhanced by complexation of calcium ions to bacterial EPS. This hypothesis was confirmed by dynamic and static light scattering measurements using extracted bacterial EPS with the addition of either MgCl2 or CaCl2 solution. We observed a dramatic increase in the hydrodynamic radius of bacterial EPS with the addition of CaCl2, but no change was observed after addition of MgCl2. Static light scattering revealed that the radius of gyration of bacterial EPS with addition of CaCl2 was 20 times larger than that with the addition of MgCl2. These observations were further confirmed by transmission electron microscopy imaging, where bacterial EPS in the presence of calcium ions was globular, while that with magnesium ions was rod-shaped. PMID:26503882

  20. Doping silver nanoparticles in AOT lyotropic lamellarphases

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The organic lyotropic liquid crystal with long-range structural order is used as templateto assemble inorganic/organic hybrid by doping pre-fabricated Ag nanoparticles. The lamellar hy-brid with both hydrophilic and hydrophobic particles doped simultaneously is realized for the firsttime. The change of template structure after doping and the stability origin of dual-doped systemare characterized by small angle X-ray scattering and polarized optical microscopy. Results showthat the interaction and space matching between surfactant bilayers and doped particles are

  1. High pressure rotating reverse osmosis for long term space missions

    Science.gov (United States)

    Christensen Pederson, Cynthia Lynn

    Rotating reverse osmosis, which uses reverse osmosis to purify water and rotating filtration to improve the efficacy of filtration, has great potential for wastewater recycling on a long term space mission. Previous investigations of a proof-of-concept device indicated that the most efficient method to improve rotating reverse osmosis performance is to increase the operational pressure. Thus, a second generation device and fluid circuit were designed, fabricated, and tested to permit high pressure operation for long time periods. The design overcame several obstacles including membrane attachment, rotating seal design, and fluid and pressure management. A theoretical model of rotating reverse osmosis was modified to properly account for the flow conditions in the new design. Tests lasting a week were conducted with a variety of model wastewaters. Significant fouling and a decrease in flux were observed after three days of testing regardless of the operational parameters. A semi-empirical model, the fouling potential, was added to the theoretical model to account for the fouling. This allowed the simulation of 48 hour cleaning cycles that significantly increased the flux of the device. Experimental investigation of the rotational speed and concentrate flow rate indicated that an increase in either parameter decreased the fouling slightly. A week long test of a wastewater ersatz with a biocide did not exhibit a decrease in flux around day three that otherwise occurred. Therefore, biofouling was identified as the primary mechanism of fouling. Rotating reverse osmosis was compared with conventional spiral wound reverse osmosis and displayed increased rejection under dead end filtration conditions. The rotating device exhibited similar rejection and increased flux compared to a tubular reverse osmosis device previously used in a NASA wastewater recovery system. The integration of the rotating device into a NASA water recovery management system was evaluated. Lastly, a

  2. 电渗析组合反渗透过程处理头孢氨苄酶法母液废水的研究%Study on the treatment of waste water of the cephalexin enzymatic process by the combination process of electrodialysis and reverse osmosis

    Institute of Scientific and Technical Information of China (English)

    阮慧敏; 黄杰; 李健; 沈江南; 王家德; 高从堦

    2014-01-01

    利用电渗析技术脱除头孢氨苄酶法母液废水中的盐分,研究了操作电压、浓缩室与淡化室流速比、温度等因素对电渗析脱盐过程的影响,并研究了反渗透膜法处理脱盐母液废水的膜通量变化趋势。实验结果表明,当淡化室、浓缩室流量均为500 L/h(流速比1∶1),操作电压为25 V,温度<30℃时,电渗析在高效脱盐的同时具有理想的有机物截留率达99.50%以上,能耗3.65 kW⋅h/kg;反渗透膜法在处理脱盐母液废水时,膜通量衰减较慢,水回收率达到75.67%。实验结果表明,利用电渗析、反渗透组合工艺处理头孢氨苄酶法母液废水具有良好的可行性。%The-salt-in-the-waste-water-of-the-cephalexin-enzymatic-process-was-removed-by-electrodialysis.-The-influences-of-operating-voltage,velocity-ratio-and-temperature-on-the-desal-ination-process-were-investigated.-The-change-of-the-permeate-flux-in-the-reverse-osmosis-sepa-ration-process-was-also-studied.-The-results-showed-that-the-electrodialysis-process-performed-better-in-desalination-with-the-organic-matter-retention-rate-reaching-99.50%,the-energy-con-sumption-of-3.65-kW⋅h/kg-at-the-conditions-of-the-flow-of-500-L/h-(velocity-ratio-of-1∶1),the-operating-voltage-of-25-V-and-temperature<30℃.-During-the-reverse-osmosis-separation-pro-cess,the-decay-of-permeate-flux-was-slow-and-acceptable,and-the-water-recovery-rate-was-75.67%.-All-results-showed-that-it-was-feasible-to-treatment-the-waste-water-of-the-cephalexin-enzymatic-process-by-a-combined-process-of-electrodialysis-and-reverse-osmosis.

  3. 反渗透和纳滤分离矿井水中营养组分和重金属离子的研究%Study on separation of nutrients and heavy metal ions from mine water by reverse osmosis and nanofiltration

    Institute of Scientific and Technical Information of China (English)

    钟常明; 王宗丽; 王汝胜; 吴坤泽

    2013-01-01

    论文选用M-RO2521超低压反渗透膜和M-N2521纳滤膜对矿井水中营养组分和重金属离子的分离效果进行了实验研究,实验考察了操作压力、温度和水回收率等因素对分离效果的影响.结果表明:反渗透膜对重金属离子及营养组分的平均截留率分别为97.5%和97%;纳滤膜对重金属离子及营养组分的平均截留率分别为92.75%和33.63%;在一定的操作条件下,组合工艺ULPRO+NF对矿井水营养组分和重金属离子的平均截留率均达97%以上,同时具有更高的水回收率.%The experimental study of mine water is conducted by a commercial ultra-low pressure reverse osmosis membrane (M-RO2521) and nanofiltration membrane (M-N2521). The effects of operating pressure, operating temperature and ratio of water callback on the performance of reverse osmosis membrane, nanofiltration membrane and combination process (ULPRO+NF) were investigated. Experiment results show that an average removal efficiency of heavy metal ions and nutrients by reverse osmosis membrane were 97.5 % and 97 % respectively; an average removal efficiency of heavy metal ions and nutrients by nanofiltration membrane were 92.75 % and 33.63 % respectively; however, an average removal efficiency of heavy metal ions and nutrients by combination process are more than 97 % and also have a higher water recovery.

  4. TiO 2光催化处理炼化污水回用反渗透浓水的研究%Study on Treatment in the Concentrated Water from Wastewater Recycling RO Unite by TiO2 Photo-catalysis*TiO2 photocatalysis treatment of petrochemical wastewater reuse reverse osmosis concentrated water

    Institute of Scientific and Technical Information of China (English)

    赵朝成; 焦叙来; 崔爱玲; 刘春爽

    2014-01-01

    Using suspended TiO 2 , photo-catalysis of concentrated water from wastewater recycling reverse osmosis units was studied under ultraviolet.The different variables affecting the removal efficiency such as reaction time , TiO2 quantity, pH value, UV irradiation intensity, H2O2 quantity and aeration quantity were investigated.The result showed that the removal rates of COD and chromaticity were 93.63% and 98.15%, respectively , under the following optimum conditions of reaction time of 2 h, TiO2 quantity of 0.6 g/L, pH value of 4, irradiation of high-pressure mercury-lamp of 500 W, H2 O2 quantity of 0.8 ml/L and aeration quantity of 0.75 L/min.%以悬浮态TiO2为催化剂,在紫外光下对炼化污水回用装置反渗透浓水进行光催化处理,采用单因素实验,考察了反应时间、 pH值、光照强度、 TiO2投加量、 H2 O2投加量、曝气量对处理效果的影响。结果表明:在反应时间为2 h, pH为4,500 W高压汞灯, TiO2投加量为0.6 g/L, H2 O2投加量为0.8 ml/L,曝气量为0.75 L/min的条件下,反渗透浓水COD的去除率可达93.63%,脱色率可达98.15%。

  5. CAPSULE REPORT: REVERSE OSMOSIS PROCESS

    Science.gov (United States)

    A failure analysis has been completed for the reverse osmosis (RO) process. The focus was on process failures that result in releases of liquids and vapors to the environment. The report includes the following: 1) A description of RO and coverage of the principles behind the proc...

  6. Vasectomy reversal : a clinical update

    NARCIS (Netherlands)

    A.P. Patel (Abhishek); R.P. Smith (Ryan)

    2016-01-01

    textabstractVasectomy is a safe and effective method of contraception used by 42-60 million men worldwide. Approximately 3%-6% of men opt for a vasectomy reversal due to the death of a child or divorce and remarriage, change in financial situation, desire for more children within the same marriage,

  7. Reverse ventilation--perfusion mismatch

    International Nuclear Information System (INIS)

    Patients having lobar airway obstruction or consolidation usually have decreases of both ventilation and perfusion on lung scans. We report three patients in whom hypoxic vasoconstriction was apparently incomplete, resulting in a ''reversed'' ventilation-perfusion mismatch. Perfusion of the hypoxic lobe on the radionuclide scan was associated with metabolic alkalosis, pulmonary venous and pulmonary arterial hypertension in these patients

  8. Nano-mechanical magnetization reversal

    OpenAIRE

    Kovalev, Alexey A.; Bauer, Gerrit E. W.; Brataas, Arne

    2004-01-01

    The dynamics of the ferromagnetic order parameter in thin magnetic films is strongly affected by the magnetomechanical coupling at certain resonance frequencies. By solving the equation of motion of the coupled mechanical and magnetic degrees of freedom we show that the magnetic-field induced magnetization switching can be strongly accelerated by the lattice and illustrate the possibility of magnetization reversal by mechanical actuation.

  9. Reversibly enhanced aqueous solubilization of volatile organic compounds using a redox-reversible surfactant

    Institute of Scientific and Technical Information of China (English)

    Yingjie Li; Senlin Tian; Hong Mo; Ping Ning

    2011-01-01

    Surfactant-enhanced remediation (SER) is an effective method for the removal of volatile organic compounds (VOCs) from contaminated soils and groundwater.To reuse the surfactant the VOCs must be separated from the surfactant solutions.The water solubility of VOCs can be enhanced using reversible surfactants with a redox-acive group,(ferrocenylmethyl)dodecyldimethylammonium bromide (Fc12) and (ferrocenylmethyl)tetradecanedimethylammonium bromide (Fc14),above and below their critical micelle concentrations (CMC) under reducing (I+) and oxidative (I2+) conditions.The CMC values of Fc12 and Fc14 in I+ are 0.94 and 0.56 mmol/L and the solubilization of toluene by Fc12 and Fc14 in I+ for toluene is higher than the solubilization achieved with sodium dodecyl sulfate,cetyltrimethylammonium bromide and Trition X-114.The solubilization capacity of the ferrocenyl surfactants for each tested VOCs ranked as follows:ethylbenzene > toluene > benzene.The solubilities of VOCs by reversible surfactant in I+ were 30% higher than those in 12+ at comparable surfactant concentrations.The effects of Fc14 concentrations on VOCs removal efficiency were as follows:benzene > toluene > ethylbenzene.However,an improved removal efficiency was achieved at low ferrocenyl surfactant concentrations.Furthermore,the reversible surfactant could be recycled through chemical approaches to remove organic pollutants,which could significantly reduce the operating costs of SER technology.

  10. Aerosol optical properties and precipitable water vapor column in the atmosphere of Norway.

    Science.gov (United States)

    Muyimbwa, Dennis; Frette, Øyvind; Stamnes, Jakob J; Ssenyonga, Taddeo; Chen, Yi-Chun; Hamre, Børge

    2015-02-20

    Between February 2012 and April 2014, we measured and analyzed direct solar radiances at a ground-based station in Bergen, Norway. We discovered that the spectral aerosol optical thickness (AOT) and precipitable water vapor column (PWVC) retrieved from these measurements have a seasonal variation with highest values in summer and lowest values in winter. The highest value of the monthly median AOT at 440 nm of about 0.16 was measured in July and the lowest of about 0.04 was measured in December. The highest value of the monthly median PWVC of about 2.0 cm was measured in July and the lowest of about 0.4 cm was measured in December. We derived Ångström exponents that were used to deduce aerosol particle size distributions. We found that coarse-mode aerosol particles dominated most of the time during the measurement period, but fine-mode aerosol particles dominated during the winter seasons. The derived Ångström exponent values suggested that aerosols containing sea salt could have been dominating at this station during the measurement period. PMID:25968219

  11. Artificial Self-Sufficient P450 in Reversed Micelles

    Directory of Open Access Journals (Sweden)

    Teruyuki Nagamune

    2010-04-01

    Full Text Available Cytochrome P450s are heme-containing monooxygenases that require electron transfer proteins for their catalytic activities. They prefer hydrophobic compounds as substrates and it is, therefore, desirable to perform their reactions in non-aqueous media. Reversed micelles can stably encapsulate proteins in nano-scaled water pools in organic solvents. However, in the reversed micellar system, when multiple proteins are involved in a reaction they can be separated into different micelles and it is then difficult to transfer electrons between proteins. We show here that an artificial self-sufficient cytochrome P450, which is an enzymatically crosslinked fusion protein composed of P450 and electron transfer proteins, showed micelle-size dependent catalytic activity in a reversed micellar system. Furthermore, the presence of thermostable alcohol dehydrogenase promoted the P450-catalyzed reaction due to cofactor regeneration.

  12. Time-Reversal of Nonlinear Waves - Applicability and Limitations

    CERN Document Server

    Ducrozet, G; Chabchoub, A

    2016-01-01

    Time-reversal (TR) refocusing of waves is one of fundamental principles in wave physics. Using the TR approach, "Time-reversal mirrors" can physically create a time-reversed wave that exactly refocus back, in space and time, to its original source regardless of the complexity of the medium as if time were going backwards. Lately, laboratory experiments proved that this approach can be applied not only in acoustics and electromagnetism but also in the field of linear and nonlinear water waves. Studying the range of validity and limitations of the TR approach may determine and quantify its range of applicability in hydrodynamics. In this context, we report a numerical study of hydrodynamic TR using a uni-directional numerical wave tank, implemented by the nonlinear high-order spectral method, known to accurately model the physical processes at play, beyond physical laboratory restrictions. The applicability of the TR approach is assessed over a variety of hydrodynamic localized and pulsating structures' configu...

  13. Reversible Watermarking Using Statistical Information

    Directory of Open Access Journals (Sweden)

    Kurugollu Fatih

    2010-01-01

    Full Text Available In most reversible watermarking methods, a compressed location map is exploited in order to ensure reversibility. Besides, in some methods, a header containing critical information is appended to the payload for the extraction and recovery process. Such schemes have a highly fragile nature; that is, changing a single bit in watermarked data may prohibit recovery of the original host as well as the embedded watermark. In this paper, we propose a new scheme in which utilizing a compressed location map is completely removed. In addition, the amount of auxiliary data is decreased by employing the adjacent pixels information. Therefore, in addition to quality improvement, independent authentication of different regions of a watermarked image is possible.

  14. Reversible Simulations of Elastic Collisions

    OpenAIRE

    Perumalla, Kalyan S.; Protopopescu, Vladimir A.

    2013-01-01

    Consider a system of N identical hard spherical particles moving in a d-dimensional box and undergoing elastic, possibly multi-particle, collisions. We develop a new algorithm that recovers the pre-collision state from the post-collision state of the system, across a series of consecutive collisions, with essentially no memory overhead. The challenge in achieving reversibility for an n-particle collision (where, n

  15. Reverse ventilation--perfusion mismatch

    Energy Technology Data Exchange (ETDEWEB)

    Palmaz, J.C.; Barnett, C.A.; Reich, S.B.; Krumpe, P.E.; Farrer, P.A.

    1984-01-01

    Patients having lobar airway obstruction or consolidation usually have decreases of both ventilation and perfusion on lung scans. We report three patients in whom hypoxic vasoconstriction was apparently incomplete, resulting in a ''reversed'' ventilation-perfusion mismatch. Perfusion of the hypoxic lobe on the radionuclide scan was associated with metabolic alkalosis, pulmonary venous and pulmonary arterial hypertension in these patients.

  16. Theory of field reversed configurations

    International Nuclear Information System (INIS)

    This final report surveys the results of work conducted on the theory of field reversed configurations. This project has spanned ten years, beginning in early 1980. During this period, Spectra Technology was one of the leading contributors to the advances in understanding FRC. The report is organized into technical topic areas, FRC formation, equilibrium, stability, and transport. Included as an appendix are papers published in archival journals that were generated in the course of this report. 33 refs

  17. Reversible Seeding in Storage Rings

    Energy Technology Data Exchange (ETDEWEB)

    Ratner, Daniel; Chao, Alex; /SLAC

    2011-12-14

    We propose to generate steady-state microbunching in a storage ring with a reversible seeding scheme. High gain harmonic generation (HGHG) and echo-enabled harmonic generation (EEHG) are two promising methods for microbunching linac electron beams. Because both schemes increase the energy spread of the seeded beam, they cannot drive a coherent radiator turn-by-turn in a storage ring. However, reversing the seeding process following the radiator minimizes the impact on the electron beam and may allow coherent radiation at or near the storage ring repetition rate. In this paper we describe the general idea and outline a proof-of-principle experiment. Electron storage rings can drive high average power light sources, and free-electron lasers (FELs) are now producing coherent light sources of unprecedented peak brightness While there is active research towards high repetition rate FELs (for example, using energy recovery linacs), at present there are still no convenient accelerator-based sources of high repetition rate, coherent radiation. As an alternative avenue, we recently proposed to establish steady-state microbunching (SSMB) in a storage ring. By maintaining steady-state coherent microbunching at one point in the storage ring, the beam generates coherent radiation at or close to the repetition rate of the storage ring. In this paper, we propose a method of generating a microbunched beam in a storage ring by using reversible versions of linac seeding schemes.

  18. CONCEPTUAL ISSUES REGARDING REVERSE LOGISTICS

    Directory of Open Access Journals (Sweden)

    Ioana Olariu

    2014-01-01

    Full Text Available As the power of consumers is growing, the product return for customer service and customer retention has become a common practice in the competitive market, which propels the recent practice of reverse logistics in companies. Many firms attracted by the value available in the flow, have proactively participated in handling returned products at the end of their usefulness or from other parts of the product life cycle. Reverse logistics is the flow and management of products, packaging, components and information from the point of consumption to the point of origin. It is a collection of practices similar to those of supply chain management, but in the opposite direction, from downstream to upstream. It involves activities such as reuse, repair, remanufacture, refurbish, reclaim and recycle. For the conventional forward logistics systems, the flow starts upstream as raw materials, later as manufactured parts and components to be assembled and continues downstream to reach customers as final products to be disposed once they reach their economic or useful lives. In reverse logistics, the disposed products are pushed upstream to be repaired, remanufactured, refurbished, and disassembled into components to be reused or as raw material to be recycled for later use.

  19. Three distinct reversing modes in the geodynamo

    Science.gov (United States)

    Gallet, Y.; Pavlov, V. E.

    2016-03-01

    The data that describe the long-term reversing behavior of the geodynamo show strong and sudden changes in magnetic reversal frequency. This concerns both the onset and the end of superchrons and most probably the occurrence of episodes characterized by extreme geomagnetic reversal frequency (>10-15 rev./Myr). To account for the complexity observed in geomagnetic reversal frequency evolution, we propose a simple scenario in which the geodynamo operates in three distinct reversing modes: i—a "normal" reversing mode generating geomagnetic polarity reversals according to a stationary random process, with on average a reversal rate of ˜3 rev./Myr; ii—a non-reversing "superchron" mode characterizing long time intervals without reversal; iii—a hyper-active reversing mode characterized by an extreme geomagnetic reversal frequency. The transitions between the different reversing modes would be sudden, i.e., on the Myr time scale. Following previous studies, we suggest that in the past, the occurrence of these transitions has been modulated by thermal conditions at the core-mantle boundary governed by mantle dynamics. It might also be possible that they were more frequent during the Precambrian, before the nucleation of the inner core, because of a stronger influence on geodynamo activity of the thermal conditions at the core-mantle boundary.

  20. 反渗透过程中双壁碳纳米管通水阻盐性能的分子动力学模拟%Molecular Dynamics Simulation of Reverse-Osmotic Salt Rejection and Water Transport through Double-Walled Carbon Nanotube

    Institute of Scientific and Technical Information of China (English)

    谌庄琳; 贺高红; 张宁; 郝策

    2015-01-01

    采用分子动力学模拟方法,探究了非常规双壁碳纳米管(DWCNT)在反渗透过程中,不同内外管间距对管道内水分子与盐离子运动行为的影响.本文采用0.5 mol∙L-1氯化钠水溶液模拟海水,内管始终采用CNT(8,8)型,并对盐水层施加恒力模拟反渗透压.重点考察盐离子数量分布与通水情况,计算水分子平均力势,并分析水分子氢键寿命与偶极矩分布.结果表明,管间距不仅影响上述各项性质,还会改变盐离子与水分子在碳管中的渗透特性.模拟结果显示,小尺寸DWCNT可以有效实现盐水分离但水通量较小,大尺寸DWCNT的水容量较大但阻盐效率不高,而中尺寸DWCNT (即:管间距为0.815 nm)则具有最佳的通水阻盐性能.本文试图从分子层面揭示了DWCNT通水阻盐机理,并为人们设计新型海水淡化渗透膜提供理论指导.%Molecular dynamics simulation was used to study the effect of the outer-wal on water flux in the inner channel by varying the inter-layer spacing of unconventional double-wal ed carbon nanotube (DWCNT) under reverse-osmosis conditions. Salt rejection and the water transport behavior inside the DWCNT were also examined. In the simulation, 0.5 mol∙L-1 NaCl aqueous solution was used to mimic seawater, and the chiral index of the inner-wal was fixed at (8, 8). A constant force on the salt solution produced pressure. Calculation of the number density profile of ions along the DWCNT axis showed that the water could be separated completely from the NaCl aqueous solution in some types of DWCNTs studied. Analyses of the hydrogen-bond lifetime, potential of mean force, and dipole moment distribution of the water molecules inside the DWCNT showed different permeabilities by water molecules and ions. An increase in the inter-layer spacing improved water flow in the DWCNT, which decreased the salt rejection performance. Final y, it was found that DWCNT with an inter-layer spacing of 0.815 nm gave the

  1. Application of reverse osmosis in feed water treatment for once-through boiler in ultra supercritical units%反渗透技术在超超临界直流锅炉补给水处理的工程应用

    Institute of Scientific and Technical Information of China (English)

    梁华杰; 苏伟; 付强

    2012-01-01

    To conserve fresh water resources, the sea water reverse osmosis (SWRO) desalination technology was used in feed water treatment of 1 000 MW ultra supercritical once-through boiler in Guangdong Huilai power plants. The system output capacity, effluent quality, desalinization ratio have reached the design requirements. The results prove that SWRO can meet the request of feed water treatment of large coastal power plant. The equipments and operation condition of SWRO system were introduced. The key problems of typical SWRO system, such as pretreatment system dosage adjustment, application of energy recovery device PX, anti permeate thick drain, and sampling methods in permeate were discussed.%为节约淡水资源,广东惠来电厂1 000 MW超超临界机组直流锅炉补给水处理工艺中采用了反渗透海水淡化(SWRO)技术并取得成功,系统出力、出水水质、脱盐率均达到设计要求,证明反渗透技术能很好满足海域电厂大型机组锅炉水处理的使用要求.介绍SWRO系统及其各设备运行情况;探讨了典型SWRO系统的关键问题:预处理系统加药量的调整,能量回收装置的应用,反渗透膜产水的取样以及反渗透浓水排放等.

  2. 14 CFR 33.97 - Thrust reversers.

    Science.gov (United States)

    2010-01-01

    ... Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Block Tests; Turbine Aircraft Engines § 33.97 Thrust reversers. (a) If the engine incorporates a reverser, the endurance calibration, operation, and vibration tests prescribed...

  3. Design of a High Performance Reversible Multiplier

    Directory of Open Access Journals (Sweden)

    Md.Belayet Ali

    2011-11-01

    Full Text Available Reversible logic circuits are increasingly used in power minimization having applications such as low power CMOS design, optical information processing, DNA computing, bioinformatics, quantum computing and nanotechnology. The problem of minimizing the number of garbage outputs is an important issue in reversible logic design. In this paper we propose a new 44 universal reversible logic gate. The proposed reversible gate can be used to synthesize any given Boolean functions. The proposed reversible gate also can be used as a full adder circuit. In this paper we have used Peres gate and the proposed Modified HNG (MHNG gate to construct the reversible fault tolerant multiplier circuit. We show that the proposed 44 reversible multiplier circuit has lower hardware complexity and it is much better and optimized in terms of number of reversible gates and number of garbage outputs with compared to the existing counterparts.

  4. Ancient Magnetic Reversals: Clues to the Geodynamo.

    Science.gov (United States)

    Hoffman, Kenneth A.

    1988-01-01

    Discusses the question posed by some that the earth's magnetic field may reverse. States that rocks magnetized by ancient fields may offer clues to the underlying reversal mechanism in the earth's core. (TW)

  5. Biofouling management by the BiosS-Treat {sup registered} -process for purification of surface water by reverse osmosis; Biofouling-Management mit dem BiosS-Treat {sup registered} -Verfahren fuer die Aufbereitung von Oberflaechenwaessern mittels Umkehrosmose-Anlagen

    Energy Technology Data Exchange (ETDEWEB)

    Keil, U.; Brueggendick, H. [STEAG encotec GmbH, Essen (Germany)

    2007-07-01

    In most plants biofouling problems are causing frequent membrane blocking with the consequences of degradation of plant performance and finally in many cases of unavoidable replacement of RO elements. In contrast to existing technologies the new biofouling management called BiosS-Treat {sup registered}, focuses on a preventive concept which is based on microbiological aspects. CEK engineering and STE-AG encotec have developed this new design of pre-treatment for the river water RO plant of the STEAG refinery power plant in Leuna, Germany. By BioS-Treat {sup registered} the availability of the RO plant was optimised significantly and the operating costs have been reduced to more then 60% in five years of operation. (orig.)

  6. Periodicity and Immortality in Reversible Computing

    OpenAIRE

    Kari, Jarkko; Ollinger, Nicolas

    2008-01-01

    Additional material available on the web at http://www.lif.univ-mrs.fr/~nollinge/rec/gnirut/ We investigate the decidability of the periodicity and the immortality problems in three models of reversible computation: reversible counter machines, reversible Turing machines and reversible one-dimensional cellular automata. Immortality and periodicity are properties that describe the behavior of the model starting from arbitrary initial configurations: immortality is the property of having at ...

  7. Fast magnetization reversal of nanoclusters in resonator

    OpenAIRE

    Yukalov, V. I.; Yukalova, E. P.

    2012-01-01

    An effective method for ultrafast magnetization reversal of nanoclusters is suggested. The method is based on coupling a nanocluster to a resonant electric circuit. This coupling causes the appearance of a magnetic feedback field acting on the cluster, which drastically shortens the magnetization reversal time. The influence of the resonator properties, nanocluster parameters, and external fields on the magnetization dynamics and reversal time is analyzed. The magnetization reversal time can ...

  8. Design of High speed Low Power Reversible Vedic multiplier and Reversible Divider

    Directory of Open Access Journals (Sweden)

    Srikanth G Department of Electronics & Communication Engineerig, Indur Institute of Engineering & Technology, Siddipet, Medak, JNTUH University, Telangana, India.

    2014-09-01

    Full Text Available This paper bring out a 32X32 bit reversible Vedic multiplier using "Urdhva Tiryakabhayam" sutra meaning vertical and crosswise, is designed using reversible logic gates, which is the first of its kind. Also in this paper we propose a new reversible unsigned division circuit. This circuit is designed using reversible components like reversible parallel adder, reversible left-shift register, reversible multiplexer, reversible n-bit register with parallel load line. The reversible vedic multiplier and reversible divider modules have been written in Verilog HDL and then synthesized and simulated using Xilinx ISE 9.2i. This reversible vedic multiplier results shows less delay and less power consumption by comparing with array multiplier.

  9. OPTIMIZATION DESIGN TO REVERSE OSMOSIS PROCESSING VC CONDENSATION WATER BASED ON QUADRATIC REGRESSION ORTHOGONAL ROTATING COMBINATION%二次回归正交旋转组合设计对反渗透处理VC凝结水工艺条件的优化

    Institute of Scientific and Technical Information of China (English)

    肖入峰; 刘景洋; 张建强

    2012-01-01

    以VC凝结水为研究对象,选择反渗透膜的温度、压力、回流比、pH为自变量,以VC凝结水TOC去除率为响应值,采用二次回归正交旋转组合设计分析法研究自变量及其交互作用对TOC去除率的影响,并建立了回归方程,通过回归方程求解和响应曲面分析确定了反渗透最优工艺操作条件,并通过贡献率法研究了各因子对响应值的影响程度.结果表明,在试验范围内各因子影响作用大小依次为pH>温度>压力>回流比;反渗透最优操作条件为:温度33.58℃,压力1.34 MPa,回流比0.49,pH为7.45,优化条件下,VC凝结水TOC去除率可达90.22%.试验验证,实际值与模型预测值拟合性良好,偏差为4.75%,优化后去除率提高了8.26%.%In order to optimize the treatment of VC condensation water by Reverse Osmosis, Quadratic regression orthogonal rotating combination design methodology was employed to investigate the effects of the independent variables and their interactions on the removal rate of TOC of VC condensation water. Reaction temperature, pressure, backflow ratio and pH were selected as independent variables, and the removal rate of total organic carbon (TOC) of VC condensation water as the response value. The best process operation conditions of Reverse osmosis was studied by response surface analysis, and the influence degree of the factors was studied by the contribution method. The results showed that in the test range size the effect of factors were pH >reaction temperature >pressure >backflow ratio; and the optimal operating conditions of reverse osmosis were temperature 33.58℃, pressure 1.34 MPa, backflow ratio 0.49, pH 7.45. In optimized conditions, the removal rate of TOC of VC condensate water was 90.22%, Experiments showed that the actual value fit the model prediction with 4.75% relative deviation, and the removal rate increases 8.26% after optimization.

  10. Garbage collection for reversible functional languages

    DEFF Research Database (Denmark)

    Mogensen, Torben Ægidius

    2015-01-01

    Reversible languages are programming languages where all programs can run both forwards and backwards. Reversible functional languages have been proposed that use symmetric pattern matching and data construction. To be reversible, these languages require linearity: Every variable must be used exa...

  11. THEORETICAL FRAMES FOR DESIGNING REVERSE LOGISTICS PROCESSES

    OpenAIRE

    Grabara, Janusz K.; Sebastian Kot

    2009-01-01

    Logistics processes of return flow became more and more important in present business practice. Because of better customer satisfaction, environmental and financial aspects many enterprises deal with reverse logistics performance. The paper is a literature review focused on the design principles of reverse logistics processes Keywords: reverse logistics, designing.

  12. Kinetic Line Voronoi Operations and Their Reversibility

    DEFF Research Database (Denmark)

    Mioc, Darka; Anton, François; Gold, Christopher;

    2010-01-01

    , as the basic algorithms for addition, deletion and moving of spatial objects. Having developed reversible map operations on the lowest level, we were able to maintain reversibility of the map updates at higher levels as well. The reversibility in GIS can be used for efficient implementation of rollback...

  13. A Functional Language for Describing Reversible Logic

    DEFF Research Database (Denmark)

    Carøe, Michael Kirkedal

    2012-01-01

    . Reversibility of descriptions is guaranteed with a type system based on linear types. The language is applied to three examples of reversible computations (ALU, linear cosine transformation, and binary adder). The paper also outlines a design flow that ensures garbage- free translation to reversible logic...

  14. Cleaning Our World through Reverse Graffiti

    Science.gov (United States)

    Randazzo, Gabe; LaJevic, Lisa

    2013-01-01

    Over the last decade artists have begun to experiment with "reverse pollution" techniques, such as reverse graffiti, which focuses on cleaning environmental surfaces. Having recently been introduced to the works of Moose, the artist known for inventing the reverse graffiti technique, the authors decided to design a curriculum to increase…

  15. REVERSE ENGINEERING AND ITS REALISTIC APPLICATIONS

    OpenAIRE

    Nikita Bakshi; Shruti Gujral

    2014-01-01

    Reverse-engineering is used for many purposes like as a learning tool, as a way to make compatible products that are cheaper than what is currently on the market. This paper discusses what is software, its type, reverse engineering, applications of reverse engineering and their tools.

  16. 14 CFR 25.933 - Reversing systems.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Reversing systems. 25.933 Section 25.933... STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant General § 25.933 Reversing systems. (a) For turbojet reversing systems— (1) Each system intended for ground operation only must be designed so that during...

  17. 14 CFR 23.933 - Reversing systems.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Reversing systems. 23.933 Section 23.933... systems. (a) For turbojet and turbofan reversing systems. (1) Each system intended for ground operation... flight and landing under any possible position of the thrust reverser. (2) Each system intended for...

  18. 壁板坡隧道富水逆断层综合超前地质预报实践%Advanced Geological Prediction of Water-rich Reverse Faults in Tunnel Wall Slope

    Institute of Scientific and Technical Information of China (English)

    曾鹏; 钟勇奇; 江星宏; 杨新安

    2016-01-01

    壁板坡隧道为沪昆客运专线最长隧道,洞身被3条逆断层带切割,围岩破碎,地下水发育,工程地质条件复杂,针对壁板坡隧道富水逆断层带,建立超前地质预报体系。在分析总结已有超前地质预报成功经验的基础上,从短距离预报和中、长距离预报的角度,建立适用于壁板坡隧道复杂地质条件的超前地质预报体系。在隧道大角度穿越杨梅山-小达村逆断层中,以TSP长距离预测、红外探水短距离预测、超前地质钻探复核预测的方式,准确探知施工中可能出现的富水破碎带的位置和富水程度,为防范施工风险,确保施工安全提供了可靠依据,验证了该超前地质预报体系的可靠性及其效果。%Bibanpo extra-long tunnel is the longest tunnel on Shanghai-Kunming high-speed railway. The tunnel body is cut by three by faults with broken surrounding rock, rich groundwater and complex engineering geological conditions. An advanced geological prediction system is established in perspective of short-term forecasting and medium and long-term forecasting for such a tunnel. The system uses TSP for long range forecasting, infrared exploring meter for short range and geological drilling to accurately detect the location of water-rich broken zone and the degree of water content, providing an important basis for construction plan and tunnel safety and verifying the effectiveness of the system in engineering application.

  19. Reversed-field pinch fusion reactor

    International Nuclear Information System (INIS)

    A conceptual engineering design of a fusion reactor based on plasma confinement in a toroidal Reversed-Field Pinch (RFP) configuration is described. The plasma is ohmically ignited by toroidal plasma currents which also inherently provide the confining magnetic fields in a toroidal chamber having major and minor radii of 12.7 and 1.5 m, respectively. The DT plasma ignites in 2 to 3 s and undergoes a transient, unrefueled burn at 10 to 20 keV for approx. 20 s to give a DT burnup of approx. 50%. The 5-s dwell period between burn pulses for plasma quench and refueling allows steady-state operation of all thermal systems outside the first wall; no auxiliary thermal capacity is required. Tritium breeding occurs in a granular Li2O blanket which is packed around an array of radially oriented water/steam coolant tubes. The slightly superheated steam emerging from this blanket directly drives a turbine that produces electrical power at an efficiency of 30%. A borated-water shield is located immediately outside the thermal blanket to protect the superconducting magnet coils. Both the superconducting poloidal and toroidal field coils are energized by homopolar motor/generators. Accounting for all major energy sinks yields a cost-optimized system with a recirculating power fraction of 0.17; the power output is 750 MWe

  20. Remote Whispering Applying Time Reversal

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Brian Eric [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-07-16

    The purpose of this project was to explore the use of time reversal technologies as a means for communication to a targeted individual or location. The idea is to have the privacy of whispering in one’s ear, but to do this remotely from loudspeakers not located near the target. Applications of this work include communicating with hostages and survivors in rescue operations, communicating imaging and operational conditions in deep drilling operations, monitoring storage of spent nuclear fuel in storage casks without wires, or clandestine activities requiring signaling between specific points. This technology provides a solution in any application where wires and radio communications are not possible or not desired. It also may be configured to self calibrate on a regular basis to adjust for changing conditions. These communications allow two people to converse with one another in real time, converse in an inaudible frequency range or medium (i.e. using ultrasonic frequencies and/or sending vibrations through a structure), or send information for a system to interpret (even allowing remote control of a system using sound). The time reversal process allows one to focus energy to a specific location in space and to send a clean transmission of a selected signal only to that location. In order for the time reversal process to work, a calibration signal must be obtained. This signal may be obtained experimentally using an impulsive sound, a known chirp signal, or other known signals. It may also be determined from a numerical model of a known environment in which the focusing is desired or from passive listening over time to ambient noise.