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Sample records for varying ph conditions

  1. TRANSFORMATION OF PB(II FROM CERRUSITE TO CHLOROPYROMORPHITE IN THE PRESENCE OF HYDROXYAPATITE UNDER VARYING CONDITIONS OF PH

    Science.gov (United States)

    The soluble Pb concentration and formation of chloropyromorphite [Pb5(PO4)3Cl] were monitored during the reaction of cerrusite (PbCO3), a highly bioavailable soil Pb species, and hydroxyapatite [Ca5(PO4)3OH] at various P/Pb molar ratios under constant and dynamic pH conditions. ...

  2. Panorama 2011: Refining: varying conditions by region

    International Nuclear Information System (INIS)

    Silva, C.

    2011-01-01

    The economic crisis has further weakened a sector that was already facing difficulties, if we look beyond the flush period (2005-2008) when, buoyed by strong demand, margins remained high and refiners could generate profits while maintaining a healthy level of activity. Falling demand and increased over-capacity in some regions - the immediate consequences of the deteriorating economic conditions over the past two years - have led to declining margins and to financial accounts being in the red. The adoption of increasingly stringent emissions standards and product specifications, burdensome regulatory requirements for refineries (for combating local pollution and reducing greenhouse gas emissions), stiffer competition from new fuels: all of these structural factors are weakening the sector, especially in industrialized nations with their more rigorous regulatory compliance. In this generally gloomy climate, numerous new projects are still being envisaged - although many have recently been postponed and tend to be concentrated in developing countries. (author)

  3. Estudo reológico da gelificação induzida pelo calor de proteínas do soro do leite e dos géis resultantes sob condições variadas de pH Rheological characterization of the heat-induced gelation of whey proteins and of the resulting gels under varied pH conditions

    Directory of Open Access Journals (Sweden)

    Cristina T. Andrade

    2005-06-01

    Full Text Available Medidas reólogicas sob cisalhamento oscilatório foram realizadas em reômetro de tensão e deformação controladas com suspensões de concentrado de proteínas do soro do leite (WPC a 10% (m/m em água e a diferentes condições de pH (pH 4,0, 4,6 e 7,0. O processo de gelificação induzida pelo calor foi investigado, assim como as propriedades viscoelásticas dos géis formados a 80°C e daqueles formados após o decréscimo da temperatura a 20°C. Foi verificado que, em presença de teores significativos de sais, procedentes do próprio soro, a concentração usada nos experimentos foi suficiente para a formação de géis macroscópicos, e que o pH exerce papel importante na formação e na natureza estrutural dos géis.Rheological measurements have been carried out in a controlled stress and strain rheometer on a whey proteins concentrate (WPC at 10% (w/w in water and at different pH conditions (pH 4.0, 4.6 and 7.0. The heat-induced gelation process was investigated, as well as the viscoelastic properties of the gels formed at 80°C and those formed after decreasing the temperature to 20°C. The results indicated that, in the presence of significant contents of salts from the whey sample, the concentration used in the experiments was sufficient for the formation of macroscopic gels, and that the pH exerts an important role on the formation and on the structural nature of the gels.

  4. Contact Dynamics of EHL Contacts under Time Varying Conditions

    NARCIS (Netherlands)

    Venner, Cornelis H.; Popovici, G.; Wijnant, Ysbrand H.; Dalmaz, G.; Lubrecht, A.A.; Priest, M

    2004-01-01

    By means of numerical simulations of two situations with time varying operating conditions it is shown that the dynamic behaviour of Elasto-Hydrodynamically Lubricated contacts in terms of vibrations can be characterized as: Changes in the mutual approach lead to film thickness changes in the inlet

  5. Vibration condition monitoring of planetary gearbox under varying external load

    Energy Technology Data Exchange (ETDEWEB)

    Bartelmus, W.; Zimroz, R. [Wroclaw University of Technology, Wroclaw (Poland)

    2009-01-15

    The paper shows that for condition monitoring of planetary gearboxes it is important to identify the external varying load condition. In the paper, systematic consideration has been taken of the influence of many factors on the vibration signals generated by a system in which a planetary gearbox is included. These considerations give the basis for vibration signal interpretation, development of the means of condition monitoring, and for the scenario of the degradation of the planetary gearbox. Real measured vibration signals obtained in the industrial environment are processed. The signals are recorded during normal operation of the diagnosed objects, namely planetary gearboxes, which are a part of the driving system used in a bucket wheel excavator, used in lignite mines. It has been found that the most important factor of the proper planetary gearbox condition is connected with perturbation of arm rotation, where an arm rotation gives rise to a specific vibration signal whose properties are depicted by a short-time Fourier transform (STFT) and Wigner-Ville distribution presented as a time-frequency map. The paper gives evidence that there are two dominant low-frequency causes that influence vibration signal modulation, i.e. the varying load, which comes from the nature of the bucket wheel digging process, and the arm/carrier rotation. These two causes determine the condition of the planetary gearboxes considered.

  6. Conditional CAPM: Time-varying Betas in the Brazilian Market

    Directory of Open Access Journals (Sweden)

    Frances Fischberg Blank

    2014-10-01

    Full Text Available The conditional CAPM is characterized by time-varying market beta. Based on state-space models approach, beta behavior can be modeled as a stochastic process dependent on conditioning variables related to business cycle and estimated using Kalman filter. This paper studies alternative models for portfolios sorted by size and book-to-market ratio in the Brazilian stock market and compares their adjustment to data. Asset pricing tests based on time-series and cross-sectional approaches are also implemented. A random walk process combined with conditioning variables is the preferred model, reducing pricing errors compared to unconditional CAPM, but the errors are still significant. Cross-sectional test show that book-to-market ratio becomes less relevant, but past returns still capture cross-section variation

  7. Atmospheric particle formation in spatially and temporally varying conditions

    Energy Technology Data Exchange (ETDEWEB)

    Lauros, J.

    2011-07-01

    Atmospheric particles affect the radiation balance of the Earth and thus the climate. New particle formation from nucleation has been observed in diverse atmospheric conditions but the actual formation path is still unknown. The prevailing conditions can be exploited to evaluate proposed formation mechanisms. This study aims to improve our understanding of new particle formation from the view of atmospheric conditions. The role of atmospheric conditions on particle formation was studied by atmospheric measurements, theoretical model simulations and simulations based on observations. Two separate column models were further developed for aerosol and chemical simulations. Model simulations allowed us to expand the study from local conditions to varying conditions in the atmospheric boundary layer, while the long-term measurements described especially characteristic mean conditions associated with new particle formation. The observations show statistically significant difference in meteorological and back-ground aerosol conditions between observed event and non-event days. New particle formation above boreal forest is associated with strong convective activity, low humidity and low condensation sink. The probability of a particle formation event is predicted by an equation formulated for upper boundary layer conditions. The model simulations call into question if kinetic sulphuric acid induced nucleation is the primary particle formation mechanism in the presence of organic vapours. Simultaneously the simulations show that ignoring spatial and temporal variation in new particle formation studies may lead to faulty conclusions. On the other hand, the theoretical simulations indicate that short-scale variations in temperature and humidity unlikely have a significant effect on mean binary water sulphuric acid nucleation rate. The study emphasizes the significance of mixing and fluxes in particle formation studies, especially in the atmospheric boundary layer. The further

  8. One-dimensional radionuclide transport under time-varying conditions

    International Nuclear Information System (INIS)

    Gelbard, F.; Olague, N.E.; Longsine, D.E.

    1990-01-01

    This paper discusses new analytical and numerical solutions presented for one-dimensional radionuclide transport under time-varying fluid-flow conditions including radioactive decay. The analytical solution assumes that all radionuclides have identical retardation factors, and is limited to instantaneous releases. The numerical solution does not have these limitations, but is tested against the limiting case given for the analytical solution. Reasonable agreement between the two solutions was found. Examples are given for the transport of a three-member radionuclide chain transported over distances and flow rates comparable to those reported for Yucca Mountain, the proposed disposal site for high-level nuclear waste

  9. Semantic conditioning of salivary pH for communication.

    Science.gov (United States)

    Ruf, Carolin A; De Massari, Daniele; Wagner-Podmaniczky, Franziska; Matuz, Tamara; Birbaumer, Niels

    2013-10-01

    Semantic conditioning of salivary pH was investigated as a new paradigm for binary communication. In a sample of eleven healthy participants, affirmation or negation of presented statements were paired with milk and lemon to condition changes in salivary pH level. Significant differences between the conditioned reactions were found at the group level. However, the analysis of pH changes on single-subject level revealed significant differences between affirmative and negative responses to the presented statements only for isolated samples in few participants. When classifying a change in pH value of more than .01 as correct response to a statement, only responses to affirmative statements reached mean accuracies of more than 60%. Improvements in the paradigm are necessary before testing it with the critical target population of patients to prove its profit for basic yes/no communication in case no other reliable means of communication could be preserved. Copyright © 2013 Elsevier B.V. All rights reserved.

  10. The in vitro digestibility of beef varies with its inherent ultimate pH.

    Science.gov (United States)

    Farouk, Mustafa M; Wu, Guojie; Frost, Deborah A; Clerens, Stefan; Knowles, Scott O

    2014-11-01

    Animal carcasses and cuts of meat are usually differentiated and valued according to size and compositional attributes. An underappreciated variable of red meat is its inherent ultimate pH (pHu) value, which affects organoleptic and processing characteristics. This study tests the hypothesis that high pHu aged meat would be more digestible than low pHu unaged (fresh) meat. Longissimus dorsi muscles collected from 59 bull carcasses had pHu values of 5.6-6.9. These were aged for 21 days at -1.5 °C, then raw and cooked (72 °C) samples were enzymatically digested at 37 °C with pepsin (pH 1.9 for 90 min) followed by pancreatin (pH 8.0 for an additional 120 min) to simulate conditions in the stomach and small intestine, respectively. Meat proteins and peptides in the digests were separated by 1D SDS PAGE. Regardless of pHu, ageing or cooking, most sarcoplasmic and myofibrillar proteins were rapidly digested by pepsin, with concomitant release of products identified by LC-MS/MS as mainly myosin-1, -2 and -7, α-actinin-2 or -3 and tropomyosin beta and alpha chains. These products were resistant to further digestion for the entire 210 min duration of the incubation. In terms of rate and extent of digestibility of these resistant products, high pHu > low pHu (P unaged (P meat samples increased with increasing pHu (P meat was highly digestible but could be further differentiated on the basis of its pHu and the ease of digestibility of proteins. Specific carcasses or cuts could be targeted to consumer groups in order to provide benefits and add value.

  11. A thermal model for photovoltaic panels under varying atmospheric conditions

    International Nuclear Information System (INIS)

    Armstrong, S.; Hurley, W.G.

    2010-01-01

    The response of the photovoltaic (PV) panel temperature is dynamic with respect to the changes in the incoming solar radiation. During periods of rapidly changing conditions, a steady state model of the operating temperature cannot be justified because the response time of the PV panel temperature becomes significant due to its large thermal mass. Therefore, it is of interest to determine the thermal response time of the PV panel. Previous attempts to determine the thermal response time have used indoor measurements, controlling the wind flow over the surface of the panel with fans or conducting the experiments in darkness to avoid radiative heat loss effects. In real operating conditions, the effective PV panel temperature is subjected to randomly varying ambient temperature and fluctuating wind speeds and directions; parameters that are not replicated in controlled, indoor experiments. A new thermal model is proposed that incorporates atmospheric conditions; effects of PV panel material composition and mounting structure. Experimental results are presented which verify the thermal behaviour of a photovoltaic panel for low to strong winds.

  12. Bioventing of gasoline-contaminated soil under varied laboratory conditions

    International Nuclear Information System (INIS)

    Hallman, M.; Shewfelt, K.; Lee, H.; Zytner, R.G.

    2002-01-01

    Bioventing is becoming a popular in situ soil remediation technology for the treatment of hydrocarbon-contaminated soil. Bioventing relies on enhancing the growth of indigenous microorganisms, which can mineralize the contaminant in the presence of sufficient nutrients. Although bioventing is currently being used as a remediation technology, there are some important questions that remain to be answered in order to optimize the process. These questions include the optimum soil moisture content, type and amount of nutrients necessary, and the best means of producing these conditions in the field. To address these questions, two distinct phases of experiments were conducted. The first experimental phase was designed to determine the optimum moisture content, C:N ratio and form of nitrogen supply for this soil. Using approximately 200g of contaminated soil in each of a series of sealed respirometers, microbial degradation of gasoline under bioventing conditions was quantified for C:N ratios of 5, 10 and 20:1, using varying mixtures of NH 4 + - and NO 3 - -N. The results of the studies indicated that the optimum soil moisture content was 15 wt%, with a C:N ratio of 10:1, using a 100% ammonium application. Using the results of the first phase, a second phase of laboratory research was initiated. Five mesoscale reactors have been developed to simulate the bioventing process that takes place in the field. These reactors are filled with approximately 4kg of gasoline-contaminated soil. The initial results are favourable. (author)

  13. Relieving Dry Mouth: Varying Levels of pH Found in Bottled Water.

    Science.gov (United States)

    Fisher, Bailey Jean; Spencer, Angela; Haywood, Van; Konchady, Gayathri

    2017-07-01

    It is estimated that 30% of people older than 60 years suffer from hyposalivation or dry mouth. Drinking water frequently has been recommended as a safe, non-pharmacologic way to combat hyposalivation. The saliva in patients with dry mouth is acidic. Beverages consumed daily may have an erosive potential on teeth. The pH and the mineral content of the beverage determine its erosive potential. An acidic beverage, therefore, may have harmful effects on mineralized tooth structures, causing erosion of enamel, dentin, and cementum. Because bottled water is both convenient and easily available, the authors tested the pH of eight common brands of bottled water. (One brand included two different bottle types, for a total of nine bottled waters tested.) To standardize the pH electrode, pH buffers of 4.7 and 10 were used. The pH was measured using the Denver Instruments basic pH meter. Six recordings were used for each brand and then averaged to report the pH. Two of the bottled water samples tested were below the critical level of 5.2 pH to 5.5 pH, the level at which erosion of enamel occurs. Six of the samples tested were below the critical pH of 6.8, at which erosion of root dentin occurs. The authors conclude that both patients and clinicians incorrectly presume bottled water to be innocuous. Clinicians should be cognizant of the erosive potential of different brands of bottled water to both educate patients and to recommend water with neutral or alkaline pH for patients with symptoms of dry mouth to prevent further deterioration and demineralization of tooth structure.

  14. Estimation of thermal sensation during varied air temperature conditions.

    Science.gov (United States)

    Katsuura, T; Tabuchi, R; Iwanaga, K; Harada, H; Kikuchi, Y

    1998-03-01

    Seven male students were exposed to four varied air temperature environments: hot (37 degrees C) to neutral (27 degrees C) (HN), neutral to hot (NH), cool (17 degrees C) to neutral (CN), and neutral to cool (NC). The air temperature was maintained at the first condition for 20 min, then was changed to the second condition after 15 min and was held there for 20 min. Each subject wore a T-shirt, briefs, trunks, and socks. Each sat on a chair and was continuously evaluated for thermal sensation, thermal comfort, and air velocity sensation. Some physiological and thermal parameters were also measured every 5 s during the experiment. The correlation between thermal sensation and skin temperature at 15 sites was found to be poor. The subjects felt much warmer during the rising phase of the air temperature (CN, NH) than during the descending phase (HN, NC) at a given mean skin temperature. However, thermal sensation at the same heat flux or at the same value of the difference between skin and air temperature (delta(Tsk - Ta)) was not so different among the four experimental conditions, and the correlation between thermal sensation and heat flux or delta(Tsk - Ta) was fairly good. The multiple regression equation of the thermal sensation (TS) on 15 sites of skin temperature (Tsk; degrees C) was calculated and the coefficient of determination (R*2) was found to be 0.656. Higher coefficients of determination were found in the equations of thermal sensation for the heat flux (H; kcal.m-2.h-1) at the right and left thighs of the subjects and on delta(Tsk - Ta) (degrees C) at 4 sites. They were as follows: TS = 2.04 - 0.016 Hright - 0.036 Hleft; R*2 = 0.717, TS = 1.649 + 0.013 delta(Tsk - Ta)UpperArm - 0.036 delta(Tsk - Ta)Chest - 0.223 delta(Tsk - Ta)Thigh-0.083 delta(Tsk - Ta)LowerLeg; R*2 = 0.752, respectively.

  15. Thermal shock behaviour of different tungsten grades under varying conditions

    Energy Technology Data Exchange (ETDEWEB)

    Wirtz, Oliver Marius

    2012-07-19

    Thermonuclear fusion power plants are a promising option to ensure the energy supply for future generations, but in many fields of research enormous challenges have to be faced. A major step on the way to the prototype fusion reactor DEMO will be ITER which is build in Cadarache, southern France. One of the most critical issues is the field of in-vessel materials and components, in particular the plasma facing materials (PFM). PFMs that will be used in a device like ITER have to withstand severe environmental conditions in terms of steady state and transient thermal loads as well as high particle fluxes such as hydrogen, helium and neutrons. Candidate wall materials are beryllium, tungsten and carbon based materials like CFC (carbon fibre composite). Tungsten is the most promising material for an application in the divertor region with very severe loading conditions and it will most probably also be used as PFM for DEMO. Hence, this work focuses on the investigation of the thermal shock response of different tungsten grades in order to understand the damage mechanisms and to identify material parameters which influence this behaviour under ITER and DEMO relevant operation conditions. Therefore the microstructure and the mechanical and thermal properties of five industrially manufactured tungsten grades were characterised. All five tungsten grades were exposed to transient thermal events with very high power densities of up to 1.27 GWm{sup -2} at varying base temperatures between RT and 600 C in the electron beam device JUDITH 1. The pulse numbers were limited to a maximum of 1000 in order to avoid immoderate workload on the test facility and to have enough time to cover a wide range of loading conditions. The results of this damage mapping enable to define different damage and cracking thresholds for the investigated tungsten grades and to identify certain material parameters which influence the location of these thresholds and the distinction of the induced

  16. Thermal shock behaviour of different tungsten grades under varying conditions

    International Nuclear Information System (INIS)

    Wirtz, Oliver Marius

    2012-01-01

    Thermonuclear fusion power plants are a promising option to ensure the energy supply for future generations, but in many fields of research enormous challenges have to be faced. A major step on the way to the prototype fusion reactor DEMO will be ITER which is build in Cadarache, southern France. One of the most critical issues is the field of in-vessel materials and components, in particular the plasma facing materials (PFM). PFMs that will be used in a device like ITER have to withstand severe environmental conditions in terms of steady state and transient thermal loads as well as high particle fluxes such as hydrogen, helium and neutrons. Candidate wall materials are beryllium, tungsten and carbon based materials like CFC (carbon fibre composite). Tungsten is the most promising material for an application in the divertor region with very severe loading conditions and it will most probably also be used as PFM for DEMO. Hence, this work focuses on the investigation of the thermal shock response of different tungsten grades in order to understand the damage mechanisms and to identify material parameters which influence this behaviour under ITER and DEMO relevant operation conditions. Therefore the microstructure and the mechanical and thermal properties of five industrially manufactured tungsten grades were characterised. All five tungsten grades were exposed to transient thermal events with very high power densities of up to 1.27 GWm -2 at varying base temperatures between RT and 600 C in the electron beam device JUDITH 1. The pulse numbers were limited to a maximum of 1000 in order to avoid immoderate workload on the test facility and to have enough time to cover a wide range of loading conditions. The results of this damage mapping enable to define different damage and cracking thresholds for the investigated tungsten grades and to identify certain material parameters which influence the location of these thresholds and the distinction of the induced damages

  17. Adsorption mechanism of alkyl polyglucoside (APG) on calcite nanoparticles in aqueous medium at varying pH

    Science.gov (United States)

    Suh, Seokjin; Choi, Kyeong-Ok; Yang, Seung-Chul; Kim, Yeong Eun; Ko, Sanghoon

    2017-07-01

    In this study, adsorption mechanism of alkyl polyglucoside (APG) on calcium carbonate (CaCO3) nanoparticles (CCNPs) in aqueous medium at varying pH was identified. An initial adsorption of APG on CCNP surface seemed to be occurred due to the van der Waals force. An initial surface charge influenced determination of a major driving force, which resulted in hydrogen bonds (pH 7) and the hydrophobic interaction (pH 10) as a main sources of adsorption of APG on the CCNP surface. Even if the initial surface charge of CCNPs had little effect on a quantitative adsorption of APG on CCNPs, eventually, it influence on the definitive adsorption structure between APG and CCNPs and improvement of dispersion stability of CCNPs in water. In conclusion, it was revealed that 0.39% APG aqueous solution was most appropriate to improve the dispersion stability of CCNPs, which is postulated to be used effectively in food and pharmaceutical fields.

  18. Varying Conditions for Hexanoic Acid Degradation with BioTiger™

    Energy Technology Data Exchange (ETDEWEB)

    Foreman, Koji [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Milliken, Charles [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Brigmon, Robin [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-07-27

    BioTiger™ (BT) is a consortium of 12 bacteria designed for petroleum waste biodegradation. BT is currently being studied and could be considered for bioremediation of the Athabasca oil sands refineries in Canada and elsewhere. The run-off ponds from the petroleum extraction processes, called tailings ponds, are a mixture of polycyclic aromatic hydrocarbons, naphthenic acids, hydrocarbons, toxic chemicals like heavy metals, water, and sand. Due to environmental regulations the oil industry would like to separate and degrade the hazardous chemical species from the tailings ponds while recycling the water. It has been shown that BT at 30 C° is able to completely degrade 10 mM hexanoic acid (HA) co-metabolically with 0.2% yeast extract (w/v) in 48 hours when starting at 0.4 OD 600nm. After establishing this stable degradation capability, variations were tested to explore the wider parameters of BT activity in temperature, pH, intermediate degradation, co-metabolic dependence, and transfer stability. Due to the vast differences in temperature at various points in the refineries, a wide range of temperatures were assessed. The results indicate that BT retains the ability to degrade HA, a model surrogate for tailings pond contaminants, at temperatures ranging from 15°C to 35°C. Hexanamide (HAM) was shown to be an intermediate generated during the degradation of HA in an earlier work and HAM is completely degraded after 48 hours, indicating that HAM is not the final product of HA degradation. Various replacements for yeast extract were attempted. Glucose, a carbon source; casein amino acids, a protein source; additional ammonia, mimicking known media; and additional phosphate with Wolffe’s vitamins and minerals all showed no significant degradation of HA compared to control. Decreasing the yeast extract concentration (0.05%) demonstrated limited but significant degradation. Finally, serial inoculations of BT were performed to determine the stability of degradation

  19. Design of Multijunction Photovoltaic Cells Optimized for Varied Atmospheric Conditions

    Directory of Open Access Journals (Sweden)

    C. Zhang

    2014-01-01

    Full Text Available Band gap engineering provides an opportunity to not only provide higher overall conversion efficiencies of the reference AM1.5 spectra but also customize PV device design for specific geographic locations and microenvironments based on atmospheric conditions characteristic to that particular location. Indium gallium nitride and other PV materials offer the opportunity for limited bandgap engineering to match spectra. The effects of atmospheric conditions such as aerosols, cloud cover, water vapor, and air mass have been shown to cause variations in spectral radiance that alters PV system performance due to both overrating and underrating. Designing PV devices optimized for spectral radiance of a particular region can result in improved PV system performance. This paper presents a new method for designing geographically optimized PV cells with using a numerical model for bandgap optimization. The geographic microclimate spectrally resolved solar flux for twelve representative atmospheric conditions for the incident radiation angle (zenith angle of 48.1° and fixed array angle of 40° is used to iteratively optimize the band gap for tandem, triple, and quad-layer of InGaN-based multijunction cells. The results of this method are illustrated for the case study of solar farms in the New York region and discussed.

  20. X-ray absorption spectroscopic study of trivalent and tetravalent actinides in solution at varying pH values

    Energy Technology Data Exchange (ETDEWEB)

    Brendebach, B.; Banik, N.L.; Marquardt, C.M.; Rothe, J.; Denecke, M.A.; Geckeis, H. [Forschungszentrum Karlsruhe (Germany). Inst. fuer Nukleare Entsorgung

    2009-07-01

    We perform X-ray absorption spectroscopy (XAS) investigations to monitor the stabilization of redox sensitive trivalent and tetravalent actinide ions in solution at acidic conditions in a pH range from 0 to 3 after treatment with holding reductants, hydroxylamine hydrochloride (NH{sub 2}OHHCl) and Rongalite (sodium hydroxymethanesulfinate, CH{sub 3}NaO{sub 3}S). X-ray absorption near edge structure (XANES) measurements clearly demonstrate the stability of the actinide species for several hours under the given experimental conditions. Hence, structural parameters can be accurately derived by extended X-ray absorption fine structure (EXAFS) investigations. The coordination structure of oxygen atoms belonging to water ligands surrounding the actinide ions does not change with increasing pH value (approximately 11 O atoms at 2.42 A in the case of U(IV) at pH 1, 9 0 atoms at 2.52 A for Np(III) at pH 1.5, and 10 O atoms at 2.49 A for Pu(III) up to pH 3), indicating that hydrolysis reactions are suppressed under the given chemical conditions. (orig.)

  1. Varied overstrain injuries of the vertebral column conditioned by evolution

    Energy Technology Data Exchange (ETDEWEB)

    Kohlbach, W

    1983-08-01

    During physiological growth of the juvenile vertebral column, various stages of stability occur which are characterized by the condition of the marginal rim of the vertebral bodies. If the vertebral juvenile column is overstrained, these variations in stability results in a variety of damage to vertebral bodies and vertebral disks. One of these lesions corresponds to Scheuermann's disease (osteochondrosis of vertebral epiphyses in juveniles). Damage of the vertebral column due to overstrain can occur only if the overstrain is applied in upright position. Since Man alone can damage his vertebral column in upright position (as a result of his evolutionary development), Scheuermann's thesis is confirmed that Scheuermann's disease is confined to Man. Spondylolysis/spondylolisthesis is also a damage caused by overstrain. Here, too, the damage can occur only if the load is exercised in upright position, with the exception of a slanted positioning of the intervertebral components.

  2. Varied overstrain injuries of the vertebral column conditioned by evolution

    International Nuclear Information System (INIS)

    Kohlbach, W.

    1983-01-01

    During physiological growth of the juvenile vertebral column, various stages of stability occur which are characterized by the condition of the marginal rim of the vertebral bodies. If the vertebral juvenile column is overstrained, these variations in stability results in a variety of damage to vertebral bodies and vertebral disks. One of these lesions corresponds to Scheuermann's disease (osteochondrosis of vertebral epiphyses in juveniles). Damage of the vertebral column due to overstrain can occur only if the overstrain is applied in upright position. Since Man alone can damage his vertebral column in upright position (as a result of his evolutionary development), Scheuermann's thesis is confirmed that Scheuermann's disease is confined to Man. Spondylolysis/spondylolisthesis is also a damage caused by overstrain. Here, too, the damage can occur only if the load is exercised in upright position, with the exception of a slanted positioning of the intervertebral components. (orig.) [de

  3. Varied overstrain injuries of the vertebral column conditioned by evolution

    Energy Technology Data Exchange (ETDEWEB)

    Kohlbach, W.

    1983-08-01

    During physiological growth of the juvenile vertebral column, various stages of stability occur which are characterized by the condition of the marginal rim of the vertebral bodies. If the vertebral juvenile column is overstrained, these variations in stability results in a variety of damage to vertebral bodies and vertebral disks. One of these lesions corresponds to Scheuermann's disease (osteochondrosis of vertebral epiphyses in juveniles). Damage of the vertebral column due to overstrain can occur only if the overstrain is applied in upright position. Since Man alone can damage his vertebral column in upright position (as a result of his evolutionary development), Scheuermann's thesis is confirmed that Scheuermann's disease is confined to Man. Spondylolysis/spondylolisthesis is also a damage caused by overstrain. Here, too, the damage can occur only if the load is exercised in upright position, with the exception of a slanted positioning of the intervertebral components.

  4. Decalcification and survival of benthic foraminifera under the combined impacts of varying pH and salinity.

    Science.gov (United States)

    Charrieau, Laurie M; Filipsson, Helena L; Nagai, Yukiko; Kawada, Sachiko; Ljung, Karl; Kritzberg, Emma; Toyofuku, Takashi

    2018-04-03

    Coastal areas display natural large environmental variability such as frequent changes in salinity, pH, and carbonate chemistry. Anthropogenic impacts - especially ocean acidification - increase this variability, which may affect the living conditions of coastal species, particularly, calcifiers. We performed culture experiments on living benthic foraminifera to study the combined effects of lowered pH and salinity on the calcification abilities and survival of the coastal, calcitic species Ammonia sp. and Elphidium crispum. We found that in open ocean conditions (salinity ∼35) and lower pH than usual values for these species, the specimens displayed resistance to shell (test) dissolution for a longer time than in brackish conditions (salinity ∼5 to 20). However, the response was species specific as Ammonia sp. specimens survived longer than E. crispum specimens when placed in the same conditions of salinity and pH. Living, decalcified juveniles of Ammonia sp. were observed and we show that desalination is one cause for the decalcification. Finally, we highlight the ability of foraminifera to survive under Ω calc  salinity and [Ca 2+ ] as building blocks are crucial for the foraminiferal calcification process. Copyright © 2018 Elsevier Ltd. All rights reserved.

  5. Weed spectrum and selectivity of tembotrione under varying environmental conditions

    Directory of Open Access Journals (Sweden)

    Gatzweiler, Elmar

    2012-03-01

    Full Text Available Tembotrione is a novel HPPD maize herbicide effective against a wide range of broadleaf and grass weeds. Some characteristics of this compound are described in this paper linking weed and crop responses following tembotrione applications to environmental parameters or use conditions. The activity of HPPD herbicides is very much dependant on the availability of light. Increasing illumination intensities following application augmented the activity levels of several comparable HPPD compounds in a growth chamber experiment. Tembotrione was shown to be more efficacious at low and high illumination intensities compared to standard herbicides applied at the same rate. At the high intensity, tembotrione retained its high efficacy from two up to four weeks after application showing a rapid and strong herbicidal activity. The activity following post-emergent treatments of tembotrione against broadleaf weeds was influenced by soil characteristics such as soil texture and organic matter content in a glasshouse test. The level of weed suppression clearly declined stronger on heavier soils than on lighter soils at a rather low application rate of 12.5 g a.i./ha and lower. This is a clear indication of residual efficacy of tembotrione. The selectivity of tembotrione was tested on numerous maize varieties following post-emergent treatment with tembotrione alone or in mixture with the safener isoxadifen-ethyl under field conditions in Germany in comparison to a standard herbicide. The level of crop phytotoxicity tended to increase in the following order: Tembotrione plus safener, standard herbicide to tembotrione alone. Only the mixture of tembotrione with safener did not cause significant adverse effects on maize. Another field experiment in the USA examined crop phytotoxicity using one maize variety in a situation of infurrow soil insecticide treatment followed by a post-emergent application of tembotrione (plus/minus isoxadifen-ethyl and standard herbicides

  6. Flux Balance Analysis of Escherichia coli under Temperature and pH Stress Conditions

    KAUST Repository

    Xu, Xiaopeng

    2015-01-01

    important roles in specific conditions and are essential genes under those conditions. E. coli is a model organism, which is widely used. It can adapt to many stress conditions, including temperature, pH, osmotic, antibiotic, etc. Underlying mechanisms

  7. Effect of environmental and cultural conditions on medium pH and explant growth performance of Douglas-fir ( Pseudotsuga menziesii) shoot cultures

    OpenAIRE

    Chen, Chien-Chih; Bates, Rick; Carlson, John

    2015-01-01

    The medium pH level of plant tissue cultures has been shown to be essential to many aspects of explant development and growth. Sensitivity or tolerance of medium pH change in vitro varies according to specific requirements of individual species. The objectives of this study are to 1) determine medium pH change over time in storage conditions and with presence of explants, 2) evaluate the effects of medium pH change on explant growth performance and 3) assess the effects of adding a pH stabili...

  8. Effect of rhizosphere pH condition on cadmium movement in a soybean plant

    International Nuclear Information System (INIS)

    Ohya, T.; Tanoi, K.; Iikura, H.; Rai, H.; Nakanishi, T.M.

    2008-01-01

    To study the effect of rhizosphere pH condition on the cadmium uptake movement, 109 Cd, was applied as a radioisotope tracer to a soybean plant grown in a water culture at pH 4.5 or pH 6.5. The distribution of 109 Cd in the soybean plant was observed radiographically with an imaging plate (IP). The amount of Cd transported from the root to the upper part of the plant at pH 4.5 was approximately two times higher than that at pH 6.5. However, the movement of Cd in the upper part of the plant was similar under both pH conditions. The distribution of Cd inside the internodes at pH 4.5 also showed similar pattern to that at pH 6.5, suggesting that once Cd reached to the vessel of the root, the movement of Cd was not dependent on rhizosphere pH conditions. (author)

  9. FORMATION OF PYROMORPHITE IN ANGLESITE-HYDROXYAPATITE SUSPENSIONS UNDER VARYING PH CONDITIONS

    Science.gov (United States)

    Addition of phosphate to lead [Pb(II)] contaminated soil to immobilize soil Pb by formation of pyromorphite has been proposed as an alternative remediation technique. Lead sulfate (PbSO4, anglesite), a Pb-bearing form found in contaminated soils and wastes, was reacted with a sy...

  10. Streptococcus oligofermentans Inhibits Streptococcus mutans in Biofilms at Both Neutral pH and Cariogenic Conditions.

    Science.gov (United States)

    Bao, Xudong; de Soet, Johannes Jacob; Tong, Huichun; Gao, Xuejun; He, Libang; van Loveren, Cor; Deng, Dong Mei

    2015-01-01

    Homeostasis of oral microbiota can be maintained through microbial interactions. Previous studies showed that Streptococcus oligofermentans, a non-mutans streptococci frequently isolated from caries-free subjects, inhibited the cariogenic Streptococcus mutans by the production of hydrogen peroxide (HP). Since pH is a critical factor in caries formation, we aimed to study the influence of pH on the competition between S. oligofermentans and S. mutans in biofilms. To this end, S. mutans and S. oligofermentans were inoculated alone or mixed at 1:1 ratio in buffered biofilm medium in a 96-well active attachment model. The single- and dual-species biofilms were grown under either constantly neutral pH or pH-cycling conditions. The latter includes two cycles of 8 h neutral pH and 16 h pH 5.5, used to mimic cariogenic condition. The 48 h biofilms were analysed for the viable cell counts, lactate and HP production. The last two measurements were carried out after incubating the 48 h biofilms in buffers supplemented with 1% glucose (pH 7.0) for 4 h. The results showed that S. oligofermentans inhibited the growth of S. mutans in dual-species biofilms under both tested pH conditions. The lactic acid production of dual-species biofilms was significantly lower than that of single-species S. mutans biofilms. Moreover, dual-species and single-species S. oligofermentans biofilms grown under pH-cycling conditions (with a 16 h low pH period) produced a significantly higher amount of HP than those grown under constantly neutral pH. In conclusion, S. oligofermentans inhibited S. mutans in biofilms not only under neutral pH, but also under pH-cycling conditions, likely through HP production. S. oligofermentans may be a compelling probiotic candidate against caries.

  11. Modelling and Control of Ionic Electroactive Polymer Actuators under Varying Humidity Conditions

    Directory of Open Access Journals (Sweden)

    S. Sunjai Nakshatharan

    2018-02-01

    Full Text Available In this work, we address the problem of position control of ionic electroactive polymer soft actuators under varying relative humidity conditions. The impact of humidity on the actuation performance of ionic actuators is studied through frequency response and impedance spectroscopy analysis. Considering the uncertain performance of the actuator under varying humidity conditions, an adaptable model using the neural network method is developed. The model uses relative humidity magnitude as one of the model parameters, making it robust to different environmental conditions. Utilizing the model, a closed-loop controller based on the model predictive controller is developed for position control of the actuator. The developed model and controller are experimentally verified and found to be capable of predicting and controlling the actuators with excellent tracking accuracy under relative humidity conditions varying in the range of 10–90%.

  12. Flux Balance Analysis of Escherichia coli under Temperature and pH Stress Conditions

    KAUST Repository

    Xu, Xiaopeng

    2015-05-12

    An interesting discovery in biology is that most genes in an organism are dispensable. That means these genes have minor effects on survival of the organism in standard laboratory conditions. One explanation of this discovery is that some genes play important roles in specific conditions and are essential genes under those conditions. E. coli is a model organism, which is widely used. It can adapt to many stress conditions, including temperature, pH, osmotic, antibiotic, etc. Underlying mechanisms and associated genes of each stress condition responses are usually different. In our analysis, we combined protein abundance data and mutant conditional fitness data into E. coli constraint-based metabolic models to study conditionally essential metabolic genes under temperature and pH stress conditions. Flux Balance Analysis was employed as the modeling method to analysis these data. We discovered lists of metabolic genes, which are E. coli dispensable genes, but conditionally essential under some stress conditions. Among these conditionally essential genes, atpA in low pH stress and nhaA in high pH stress found experimental evidences from previous studies. Our study provides new conditionally essential gene candidates for biologists to explore stress condition mechanisms.

  13. Computing Conditional VaR using Time-varying CopulasComputing Conditional VaR using Time-varying Copulas

    Directory of Open Access Journals (Sweden)

    Beatriz Vaz de Melo Mendes

    2005-12-01

    Full Text Available It is now widespread the use of Value-at-Risk (VaR as a canonical measure at risk. Most accurate VaR measures make use of some volatility model such as GARCH-type models. However, the pattern of volatility dynamic of a portfolio follows from the (univariate behavior of the risk assets, as well as from the type and strength of the associations among them. Moreover, the dependence structure among the components may change conditionally t past observations. Some papers have attempted to model this characteristic by assuming a multivariate GARCH model, or by considering the conditional correlation coefficient, or by incorporating some possibility for switches in regimes. In this paper we address this problem using time-varying copulas. Our modeling strategy allows for the margins to follow some FIGARCH type model while the copula dependence structure changes over time.

  14. Is Your Drinking Water Acidic? A Comparison of the Varied pH of Popular Bottled Waters.

    Science.gov (United States)

    Wright, Kellie F

    2015-06-01

    Dental professionals continually educate patients on the dangers of consuming acidic foods and beverages due to their potential to contribute to dental erosion and tooth decay. Excess acid in the diet can also lead to acidosis, which causes negative systemic side effects. However, water is not typically categorized as acidic. The purpose of this in-vitro study was to investigate the pH levels of several popular brands of bottled water and compare them to various other acidic beverages. Two different brands of marketed alkaline water (with a pH of 8.8 or higher) were also studied, tested for acidity and described. A pilot in-vitro study was conducted to determine the pH levels of a convenience sample of popular brands of bottled water, tap water and other known acidic beverages in comparison with the pH values reported on the respective manufacturers' website. Each beverage was tested in a laboratory using a calibrated Corning pH meter model 240, and waters were compared to the corresponding company's testified pH value. Waters were also compared and contrasted based on their process of purification. The data was then compiled and analyzed descriptively. The pH values for the tested beverages and bottled waters were found to be predominantly acidic. Ten out of the 14 beverages tested were acidic (pHwaters were neutral (pH=7) and 2 bottled waters were alkaline (pH>7). The majority of waters tested had a more acidic pH when tested in the lab than the value listed in their water quality reports. It is beneficial for the health care provider to be aware of the potential acidity of popular bottled drinking waters and educate patients accordingly. Copyright © 2015 The American Dental Hygienists’ Association.

  15. Mobility of Iron-Cyanide Complexes in a Humic Topsoil under Varying Redox Conditions

    Directory of Open Access Journals (Sweden)

    Thilo Rennert

    2009-01-01

    Full Text Available The potentially toxic Fe-CN complexes ferricyanide, [FeIII(CN6]3−, and ferrocyanide, [FeII(CN6]4−, undergo a variety of redox processes in soil, which affect their mobility. We carried out microcosm experiments with suspensions of a humic topsoil (pH 5.3; Corg 107 g kg-1 to which we added ferricyanide (20 mg l-1. We varied the redox potential (EH from −280 to 580 mV by using O2, N2 and glucose. The decrease of EH led to decreasing concentrations of Fe-CN complexes and partial reductive dissolution of (hydrous Fe and Mn oxides. The dynamics of aqueous Fe-CN concentrations was characterized by decreasing concentrations when the pH rose and the EH dropped. We attribute these dependencies to adsorption on organic surfaces, for which such a pH/EH behavior has been shown previously. Adsorption was reversible, because when the pH and EH changed into the opposite direction, desorption occurred. This study demonstrates the possible impact of soil organic matter on the fate of Fe-CN complexes in soil.

  16. Bearing Condition Recognition and Degradation Assessment under Varying Running Conditions Using NPE and SOM

    Directory of Open Access Journals (Sweden)

    Shaohui Zhang

    2014-01-01

    Full Text Available Manifold learning methods have been widely used in machine condition monitoring and fault diagnosis. However, the results reported in these studies focus on the machine faults under stable loading and rotational speeds, which cannot interpret the practical machine running. Rotating machine is always running under variable speeds and loading, which makes the vibration signal more complicated. To address such concern, the NPE (neighborhood preserving embedding is applied for bearing fault classification. Compared with other algorithms (PCA, LPP, LDA, and ISOP, the NPE performs well in feature extraction. Since the traditional time domain signal denoising is time consuming and memory consuming, we denoise the signal features directly in feature space. Furthermore, NPE and SOM (self-organizing map are combined to assess the bearing degradation performance. Simulation and experiment results validate the effectiveness of the proposed method.

  17. Determination of calcium salt solubility with changes in pH and P(CO(2)), simulating varying gastrointestinal environments.

    Science.gov (United States)

    Goss, Sandra L; Lemons, Karen A; Kerstetter, Jane E; Bogner, Robin H

    2007-11-01

    The amount of calcium available for absorption is dependent, in part, on its sustained solubility in the gastrointestinal (GI) tract. Many calcium salts, which are the calcium sources in supplements and food, have pH-dependent solubility and may have limited availability in the small intestine, the major site of absorption. The equilibrium solubility of four calcium salts (calcium oxalate hydrate, calcium citrate tetrahydrate, calcium phosphate, calcium glycerophosphate) were determined at controlled pH values (7.5, 6.0, 4.5 and solubility of calcium carbonate was also measured at pH 7.5, 6.0 and 4.5 with two CO(2) environments (0.3 and 152 mmHg) above the solution. The precipitation profile of CaCO(3) was calculated using in-vivo data for bicarbonate and pH from literature and equilibrium calculations. As pH increased, the solubility of each calcium salt increased. However, in distilled water each salt produced a different pH, affecting its solubility value. Although calcium citrate does have a higher solubility than CaCO(3) in water, there is little difference when the pH is controlled at pH 7.5. The partial pressure of CO(2) also played a role in calcium carbonate solubility, depressing the solubility at pH 7.5. The calculations of soluble calcium resulted in profiles of available calcium, which agreed with previously published in-vivo data on absorbed calcium. The experimental data illustrate the impact of pH and CO(2) on the solubility of many calcium salts in the presence of bicarbonate secretions in the intestine. Calculated profiles using in-vivo calcium and bicarbonate concentrations demonstrate that large calcium doses may not further increase intestinal calcium absorption once the calcium carbonate solubility product has been reached.

  18. Towards artificial intelligence based diesel engine performance control under varying operating conditions using support vector regression

    Directory of Open Access Journals (Sweden)

    Naradasu Kumar Ravi

    2013-01-01

    Full Text Available Diesel engine designers are constantly on the look-out for performance enhancement through efficient control of operating parameters. In this paper, the concept of an intelligent engine control system is proposed that seeks to ensure optimized performance under varying operating conditions. The concept is based on arriving at the optimum engine operating parameters to ensure the desired output in terms of efficiency. In addition, a Support Vector Machines based prediction model has been developed to predict the engine performance under varying operating conditions. Experiments were carried out at varying loads, compression ratios and amounts of exhaust gas recirculation using a variable compression ratio diesel engine for data acquisition. It was observed that the SVM model was able to predict the engine performance accurately.

  19. Leading-Edge Noise Prediction of General Airfoil Profiles with Spanwise-Varying Inflow Conditions

    NARCIS (Netherlands)

    Miotto, Renato Fuzaro; Wolf, William Roberto; De Santana, Leandro Dantas

    2018-01-01

    This paper presents a study of the leading-edge noise radiated by an airfoil undergoing a turbulent inflow. The noise prediction of generic airfoil profiles subjected to spanwise-varying inflow conditions is performed with the support of Amiet’s theory and the inverse strip technique. In the

  20. Leading-Edge Noise Prediction of General Airfoil Profiles with Spanwise-Varying Inflow Conditions

    NARCIS (Netherlands)

    Miotto, Renato Fuzaro; Wolf, William Roberto; De Santana, Leandro Dantas

    This paper presents a study of the leading-edge noise radiated by an airfoil undergoing a turbulent inflow. The noise prediction of generic airfoil profiles subjected to spanwise-varying inflow conditions is performed with the support of Amiet’s theory and the inverse strip technique. In the

  1. Incipient Fault Detection for Rolling Element Bearings under Varying Speed Conditions

    Directory of Open Access Journals (Sweden)

    Lang Xue

    2017-06-01

    Full Text Available Varying speed conditions bring a huge challenge to incipient fault detection of rolling element bearings because both the change of speed and faults could lead to the amplitude fluctuation of vibration signals. Effective detection methods need to be developed to eliminate the influence of speed variation. This paper proposes an incipient fault detection method for bearings under varying speed conditions. Firstly, relative residual (RR features are extracted, which are insensitive to the varying speed conditions and are able to reflect the degradation trend of bearings. Then, a health indicator named selected negative log-likelihood probability (SNLLP is constructed to fuse a feature set including RR features and non-dimensional features. Finally, based on the constructed SNLLP health indicator, a novel alarm trigger mechanism is designed to detect the incipient fault. The proposed method is demonstrated using vibration signals from bearing tests and industrial wind turbines. The results verify the effectiveness of the proposed method for incipient fault detection of rolling element bearings under varying speed conditions.

  2. Incipient Fault Detection for Rolling Element Bearings under Varying Speed Conditions.

    Science.gov (United States)

    Xue, Lang; Li, Naipeng; Lei, Yaguo; Li, Ningbo

    2017-06-20

    Varying speed conditions bring a huge challenge to incipient fault detection of rolling element bearings because both the change of speed and faults could lead to the amplitude fluctuation of vibration signals. Effective detection methods need to be developed to eliminate the influence of speed variation. This paper proposes an incipient fault detection method for bearings under varying speed conditions. Firstly, relative residual (RR) features are extracted, which are insensitive to the varying speed conditions and are able to reflect the degradation trend of bearings. Then, a health indicator named selected negative log-likelihood probability (SNLLP) is constructed to fuse a feature set including RR features and non-dimensional features. Finally, based on the constructed SNLLP health indicator, a novel alarm trigger mechanism is designed to detect the incipient fault. The proposed method is demonstrated using vibration signals from bearing tests and industrial wind turbines. The results verify the effectiveness of the proposed method for incipient fault detection of rolling element bearings under varying speed conditions.

  3. Remaining useful life estimation for deteriorating systems with time-varying operational conditions and condition-specific failure zones

    Directory of Open Access Journals (Sweden)

    Li Qi

    2016-06-01

    Full Text Available Dynamic time-varying operational conditions pose great challenge to the estimation of system remaining useful life (RUL for the deteriorating systems. This paper presents a method based on probabilistic and stochastic approaches to estimate system RUL for periodically monitored degradation processes with dynamic time-varying operational conditions and condition-specific failure zones. The method assumes that the degradation rate is influenced by specific operational condition and moreover, the transition between different operational conditions plays the most important role in affecting the degradation process. These operational conditions are assumed to evolve as a discrete-time Markov chain (DTMC. The failure thresholds are also determined by specific operational conditions and described as different failure zones. The 2008 PHM Conference Challenge Data is utilized to illustrate our method, which contains mass sensory signals related to the degradation process of a commercial turbofan engine. The RUL estimation method using the sensor measurements of a single sensor was first developed, and then multiple vital sensors were selected through a particular optimization procedure in order to increase the prediction accuracy. The effectiveness and advantages of the proposed method are presented in a comparison with existing methods for the same dataset.

  4. Globally exponential stability condition of a class of neural networks with time-varying delays

    International Nuclear Information System (INIS)

    Liao, T.-L.; Yan, J.-J.; Cheng, C.-J.; Hwang, C.-C.

    2005-01-01

    In this Letter, the globally exponential stability for a class of neural networks including Hopfield neural networks and cellular neural networks with time-varying delays is investigated. Based on the Lyapunov stability method, a novel and less conservative exponential stability condition is derived. The condition is delay-dependent and easily applied only by checking the Hamiltonian matrix with no eigenvalues on the imaginary axis instead of directly solving an algebraic Riccati equation. Furthermore, the exponential stability degree is more easily assigned than those reported in the literature. Some examples are given to demonstrate validity and excellence of the presented stability condition herein

  5. Interactions in heated milk model systems with different ratios of nanoparticulated whey protein at varying pH

    DEFF Research Database (Denmark)

    Liu, Guanchen; Jæger, Tanja C.; Nielsen, Søren B.

    2017-01-01

    To better understand the interactions between nanoparticulated whey protein (NWP) and other milk proteins during acidification, milk model systems were diluted to 0.5% protein concentration and adjusted to pH of 6.0-4.5 following homogenisation and heat treatment. The diluted systems with different...... concentrations of NWP (0-0.5%) were characterised in terms of particle size, viscosity, surface charge and hydrophobicity. When pH was adjusted to 5.5, aggregation was initiated at levels of NWP (0.25-0.5%) leading to significant increase in particle size and viscosity. Pure NWP (0.5%) showed largest initial...

  6. Effect of Sulfur Concentration and PH Conditions on Akaganeite Formation: Understanding Akaganeite Formation Conditions in Yellowknife Bay, Gale Crater, Mars

    Science.gov (United States)

    Fox, A.; Peretyazhko, T.; Sutter, B.; Niles, P.; Ming, D. W.; Morris, R. V.

    2015-01-01

    The Chemistry and Mineralogy Instrument (CHEMIN) on board the Mars Science Laboratory (MSL) Curiosity Rover identified minor amounts of akaganeite (beta-FeOOH) at Yellowknife Bay, Mars. There is also evidence for akaganeite at other localities on Mars from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM). Akaganeite is an iron(III) hydroxide with a hollandite- like structure and Cl in its tunnels. Terrestrial akaganeite usually forms in Cl-rich environments under acidic, oxidizing conditions. Previous studies of akaganeite have revealed that akaganeite formation is affected by the presence of sulfate (hereafter denoted as S. The prediction of circumneutral pH coupled with the detection of S at Yellowknife Bay dictate that work is needed to determine how S and pH together affect akaganeite formation. The goal of this work is to study how changes in both S concentration and pH influence akaganeite precipitation. Akaganeite formation was investigated at S/Cl molar ratios of 0, 0.017, 0.083, 0.17 and 0.33 at pH 1.5, 2, and 4. Results are anticipated to provide combined S concentration and pH constraints on akaganeite formation in Yellowknife Bay and elsewhere on Mars. Knowledge of solution pH and S concentrations can be utilized in understanding microbial habitability potential on the Martian surface.

  7. Modelling Conditional and Unconditional Heteroskedasticity with Smoothly Time-Varying Structure

    DEFF Research Database (Denmark)

    Amado, Christina; Teräsvirta, Timo

    multiplier type misspecification tests. Finite-sample properties of these procedures and tests are examined by simulation. An empirical application to daily stock returns and another one to daily exchange rate returns illustrate the functioning and properties of our modelling strategy in practice......In this paper, we propose two parametric alternatives to the standard GARCH model. They allow the conditional variance to have a smooth time-varying structure of either ad- ditive or multiplicative type. The suggested parameterizations describe both nonlinearity and structural change...... in the conditional and unconditional variances where the transition between regimes over time is smooth. A modelling strategy for these new time-varying parameter GARCH models is developed. It relies on a sequence of Lagrange multiplier tests, and the adequacy of the estimated models is investigated by Lagrange...

  8. Improving Delay-Range-Dependent Stability Condition for Systems with Interval Time-Varying Delay

    Directory of Open Access Journals (Sweden)

    Wei Qian

    2013-01-01

    Full Text Available This paper discusses the delay-range-dependent stability for systems with interval time-varying delay. Through defining the new Lyapunov-Krasovskii functional and estimating the derivative of the LKF by introducing new vectors, using free matrices and reciprocally convex approach, the new delay-range-dependent stability conditions are obtained. Two well-known examples are given to illustrate the less conservatism of the proposed theoretical results.

  9. A new fluorescent pH probe for extremely acidic conditions

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Yu [School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China); Taishan College, Shandong University, Jinan 250100 (China); Jiang, Zheng [School of Life Science, Shandong University, Jinan 250100 (China); Taishan College, Shandong University, Jinan 250100 (China); Xiao, Yu [School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China); Taishan College, Shandong University, Jinan 250100 (China); Bi, Fu-Zhen [School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China); Miao, Jun-Ying, E-mail: miaojy@sdu.edu.cn [School of Life Science, Shandong University, Jinan 250100 (China); Zhao, Bao-Xiang, E-mail: bxzhao@sdu.edu.cn [School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China)

    2014-04-01

    A new coumarin-based fluorescent probe can detect highly acidic conditions in both solution and bacteria with high selectivity and sensitivity. Highlights: • A new fluorescence probe for very low pH was synthesized and characterized. • The probe can monitor pH in solution and bacteria. • The two-step protonation of N atoms of the probe leads to fluorescence quenching. Abstract: A novel turn-off fluorescent probe based on coumarin and imidazole moiety for extremely acidic conditions was designed and developed. The probe with pKa = 2.1 is able to respond to very low pH value (below 3.5) with high sensitivity relying on fluorescence quenching at 460 nm in fluorescence spectra or the ratios of absorbance maximum at 380 nm to that at 450 nm in UV–vis spectra. It can quantitatively detect pH value based on equilibrium equation, pH = pKa -log[(Ix - Ib)/(Ia - Ix)]. It had very short response time that was less than 1 min, good reversibility and nearly no interference from common metal ions. Moreover, using ¹H NMR analysis and theoretical calculation of molecular orbital, we verified that a two-step protonation process of two N atoms of the probe leaded to photoinduced electron transfer (PET), which was actually the mechanism of the fluorescence quenching phenomenon under strongly acidic conditions. Furthermore, the probe was also applied to imaging strong acidity in bacteria, E.coli and had good effect. This work illustrates that the new probe could be a practical and ideal pH indicator for strongly acidic conditions with good biological significance.

  10. Sex differences in in-group cooperation vary dynamically with competitive conditions and outcomes.

    Science.gov (United States)

    Bailey, Drew H; Winegard, Benjamin; Oxford, Jon; Geary, David C

    2012-03-18

    Men's but not women's investment in a public goods game varied dynamically with the presence or absence of a perceived out-group. Three hundred fifty-four (167 male) young adults participated in multiple iterations of a public goods game under intergroup and individual competition conditions. Participants received feedback about whether their investments in the group were sufficient to earn a bonus to be shared among all in-group members. Results for the first trial confirm previous research in which men's but not women's investments were higher when there was a competing out-group. We extended these findings by showing that men's investment in the in-group varied dynamically by condition depending on the outcome of the previous trial: In the group condition, men, but not women, decreased spending following a win (i.e., earning an in-group bonus). In the individual condition, men, but not women, increased spending following a win. We hypothesize that these patterns reflect a male bias to calibrate their level of in-group investment such that they sacrifice only what is necessary for their group to successfully compete against a rival group.

  11. Sex Differences in In-Group Cooperation Vary Dynamically with Competitive Conditions and Outcomes

    Directory of Open Access Journals (Sweden)

    Drew H. Bailey

    2012-01-01

    Full Text Available Men's but not women's investment in a public goods game varied dynamically with the presence or absence of a perceived out-group. Three hundred fifty-four (167 male young adults participated in multiple iterations of a public goods game under intergroup and individual competition conditions. Participants received feedback about whether their investments in the group were sufficient to earn a bonus to be shared among all in-group members. Results for the first trial confirm previous research in which men's but not women's investments were higher when there was a competing out-group. We extended these findings by showing that men's investment in the in-group varied dynamically by condition depending on the outcome of the previous trial: In the group condition, men, but not women, decreased spending following a win (i.e., earning an in-group bonus. In the individual condition, men, but not women, increased spending following a win. We hypothesize that these patterns reflect a male bias to calibrate their level of in-group investment such that they sacrifice only what is necessary for their group to successfully compete against a rival group.

  12. The effect of varying talker identity and listening conditions on gaze behavior during audiovisual speech perception.

    Science.gov (United States)

    Buchan, Julie N; Paré, Martin; Munhall, Kevin G

    2008-11-25

    During face-to-face conversation the face provides auditory and visual linguistic information, and also conveys information about the identity of the speaker. This study investigated behavioral strategies involved in gathering visual information while watching talking faces. The effects of varying talker identity and varying the intelligibility of speech (by adding acoustic noise) on gaze behavior were measured with an eyetracker. Varying the intelligibility of the speech by adding noise had a noticeable effect on the location and duration of fixations. When noise was present subjects adopted a vantage point that was more centralized on the face by reducing the frequency of the fixations on the eyes and mouth and lengthening the duration of their gaze fixations on the nose and mouth. Varying talker identity resulted in a more modest change in gaze behavior that was modulated by the intelligibility of the speech. Although subjects generally used similar strategies to extract visual information in both talker variability conditions, when noise was absent there were more fixations on the mouth when viewing a different talker every trial as opposed to the same talker every trial. These findings provide a useful baseline for studies examining gaze behavior during audiovisual speech perception and perception of dynamic faces.

  13. Study of the crystallographic phase change on copper (I) selenide thin films prepared through chemical bath deposition by varying the pH of the solution

    Energy Technology Data Exchange (ETDEWEB)

    Sandoval-Paz, M.G., E-mail: myrnasandoval@udec.cl [Departament of Physics, Faculty of Physical Sciences and Mathematics, University of Concepcion, Box 160-C, Concepción (Chile); Rodríguez, C.A. [Department of Materials Engineering, Faculty of Engineering, University of Concepción, Edmundo Larenas 270, Concepción 4070409 (Chile); Porcile-Saavedra, P.F. [Departament of Physics, Faculty of Physical Sciences and Mathematics, University of Concepcion, Box 160-C, Concepción (Chile); Trejo-Cruz, C. [Department of Physics, Faculty of Science, University of Biobío, Avenue Collao 1202, Box 5C, Concepción 4051381 (Chile)

    2016-07-15

    Copper (I) selenide thin films with orthorhombic and cubic structure were deposited on glass substrates by using the chemical bath deposition technique. The effects of the solution pH on the films growth and subsequently the structural, optical and electrical properties of the films were studied. Films with orthorhombic structure were obtained from baths wherein both metal complex and hydroxide coexist; while films with cubic structure were obtained from baths where the metal hydroxide there is no present. The structural modifications are accompanied by changes in bandgap energy, morphology and electrical resistivity of the films. - Graphical abstract: “Study of the crystallographic phase change on copper (I) selenide thin films prepared through chemical bath deposition by varying the pH of the solution” by M. G. Sandoval-Paz, C. A. Rodríguez, P. F. Porcile-Saavedra, C. Trejo-Cruz. Display Omitted - Highlights: • Copper (I) selenide thin films were obtained by chemical bath deposition. • Orthorhombic to cubic phase change was induced by varying the reaction solution pH. • Orthorhombic phase is obtained mainly from a hydroxides cluster mechanism. • Cubic phase is obtained mainly from an ion by ion mechanism. • Structural, optical and electrical properties are presented as a function of pH.

  14. Understanding and simulating vibrations of plain bridge cables under varying meteorological conditions

    DEFF Research Database (Denmark)

    Matteoni, Giulia

    amplitude peak to peak amplitudes, occurred. This latter behaviour was likely to be associated to dry inclined galloping. Passive dynamic wind tunnel tests were finally undertaken in presence of rain, using the same cable model as adopted in the dry state. The tests served to improve the current......The dissertation investigates the phenomenon of wind induced vibration of bridge cables under varying meteorological conditions. A twin research approach is adopted, where wind tunnel investigation of full-scale bridge cable section models is paralleled with theoretical modelling. A literature......-scale monitoring, wind tunnel testing and theoretical modelling. An extensive wind tunnel test campaign was then undertaken in order to further understand the onset conditions and characteristics of instability in the different climatic conditions described in the literature. Tests were separated into two...

  15. Synthesis of different-sized silver nanoparticles by simply varying reaction conditions with leaf extracts of Bauhinia variegata L.

    Science.gov (United States)

    Kumar, V; Yadav, S K

    2012-03-01

    Green synthesis of nanoparticles is one of the crucial requirements in today's climate change scenario all over the world. In view of this, leaf extract (LE) of Bauhinia variegata L. possessing strong antidiabetic and antibacterial properties has been used to synthesise silver nanoparticles (SNP) in a controlled manner. Various-sized SNP (20-120 nm) were synthesised by varying incubation temperature, silver nitrate and LE concentrations. The rate of SNP synthesis and their size increased with increase in AgNO(3) concentration up to 4 mM. With increase in LE concentration, size and aggregation of SNP was increased. The size and aggregation of SNP were also increased at temperatures above and below 40°C. This has suggested that size and dispersion of SNP can be controlled by varying reaction components and conditions. Polarity-based fractionation of B. variegata LE has suggested that only water-soluble fraction is responsible for SNP synthesis. Fourier transform infrared spectroscopy analysis revealed the attachment of polyphenolic and carbohydrate moieties to SNP. The synthesised SNPs were found stable in double distilled water, BSA and phosphate buffer (pH 7.4). On the contrary, incubation of SNP with NaCl induced aggregation. This suggests the safe use of SNP for various in vivo applications.

  16. Differences in displayed pump flow compared to measured flow under varying conditions during simulated cardiopulmonary bypass.

    LENUS (Irish Health Repository)

    Hargrove, M

    2008-07-01

    Errors in blood flow delivery due to shunting have been reported to reduce flow by, potentially, up to 40-83% during cardiopulmonary bypass. The standard roller-pump measures revolutions per minute and a calibration factor for different tubing sizes calculates and displays flow accordingly. We compared displayed roller-pump flow with ultrasonically measured flow to ascertain if measured flow correlated with the heart-lung pump flow reading. Comparison of flows was measured under varying conditions of pump run duration, temperature, viscosity, varying arterial\\/venous loops, occlusiveness, outlet pressure, use of silicone or polyvinyl chloride (PVC) in the roller race, different tubing diameters, and use of a venous vacuum-drainage device.

  17. The effect of varied pH on the luminescence characteristics of antibody-mercaptoacetic acid conjugated ZnS nanowires

    Science.gov (United States)

    Chaudhry, Madeeha; Rehman, Malik Abdul; Gul, Asghari; Qamar, Raheel; Bhatti, Arshad Saleem

    2017-11-01

    We demonstrate here that the effect of varied pH of the media on the photoluminescence (PL) properties of mercaptoacetic acid (MAA) and digoxin antibody (Ab) conjugated zinc sulphide (ZnS) nanowires. The charge-transfer kinetics from MAA to ZnS and vice versa showed a profound effect on the luminescence of ZnS defect states. The PL intensity of the ZnS defect states showed strong dependence on the value of pH with respect to the pKa of MAA. The carboxyl and thiol group of MAA in the protonated (pH pKa) states resulted in the quenched PL intensity. While for pH ∼ pKa, the PL intensity was regained as there was equal probability of both protonated and deprotonated carboxyl and thiol groups. These findings indicated that pH of the environment is a key parameter for the use of MAA-Ab conjugated ZnS nanowires as an optical biomarker.

  18. An in vitro experimental study of flow past aortic valve under varied pulsatile conditions

    Science.gov (United States)

    Zhang, Ruihang; Zhang, Yan

    2017-11-01

    Flow past aortic valve represents a complex fluid-structure interaction phenomenon that involves pulsatile, vortical, and turbulent conditions. The flow characteristics immediately downstream of the valve, such as the variation of pulsatile flow velocity, formation of vortices, distribution of shear stresses, are of particular interest to further elucidate the role of hemodynamics in various aortic diseases. However, the fluid dynamics of a realistic aortic valve is not fully understood. Particularly, it is unclear how the flow fields downstream of the aortic valve would change under varied pulsatile inlet boundary conditions. In this study, an in vitro experiment has been conducted to investigate the flow fields downstream of a silicone aortic valve model within a cardiovascular flow simulator. Phased-locked Particle Image Velocimetry measurements were performed to map the velocity fields and Reynolds normal and shear stresses at different phases in a cardiac cycle. Temporal variations of pressure across the valve model were measured using high frequency transducers. Results have been compared for different pulsatile inlet conditions, including varied frequencies (heart rates), magnitudes (stroke volumes), and cardiac contractile functions (shapes of waveforms).

  19. Applicability of common stomatal conductance models in maize under varying soil moisture conditions.

    Science.gov (United States)

    Wang, Qiuling; He, Qijin; Zhou, Guangsheng

    2018-07-01

    In the context of climate warming, the varying soil moisture caused by precipitation pattern change will affect the applicability of stomatal conductance models, thereby affecting the simulation accuracy of carbon-nitrogen-water cycles in ecosystems. We studied the applicability of four common stomatal conductance models including Jarvis, Ball-Woodrow-Berry (BWB), Ball-Berry-Leuning (BBL) and unified stomatal optimization (USO) models based on summer maize leaf gas exchange data from a soil moisture consecutive decrease manipulation experiment. The results showed that the USO model performed best, followed by the BBL model, BWB model, and the Jarvis model performed worst under varying soil moisture conditions. The effects of soil moisture made a difference in the relative performance among the models. By introducing a water response function, the performance of the Jarvis, BWB, and USO models improved, which decreased the normalized root mean square error (NRMSE) by 15.7%, 16.6% and 3.9%, respectively; however, the performance of the BBL model was negative, which increased the NRMSE by 5.3%. It was observed that the models of Jarvis, BWB, BBL and USO were applicable within different ranges of soil relative water content (i.e., 55%-65%, 56%-67%, 37%-79% and 37%-95%, respectively) based on the 95% confidence limits. Moreover, introducing a water response function, the applicability of the Jarvis and BWB models improved. The USO model performed best with or without introducing the water response function and was applicable under varying soil moisture conditions. Our results provide a basis for selecting appropriate stomatal conductance models under drought conditions. Copyright © 2018 Elsevier B.V. All rights reserved.

  20. Biosynthesis of schwertmannite by Acidithiobacillus ferrooxidans cell suspensions under different pH condition

    Energy Technology Data Exchange (ETDEWEB)

    Liao Yuehua [Department of Environmental Engineering, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095 (China); Zhou Lixiang [Department of Environmental Engineering, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095 (China)], E-mail: lxzhou@njau.edu.cn; Liang Jianru; Xiong Huixin [Department of Environmental Engineering, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095 (China)

    2009-01-01

    Oxidation of FeSO{sub 4} solution with initial pH in the range of 1.40-3.51 by Acidithiobacillus ferrooxidans LX5 cell at 26 deg. C and subsequent precipitation of resulting Fe(III) were investigated in the present study. Results showed that the oxidation rate of Fe(II) was around 1.2-3.9 mmol l{sup -1} h{sup -1}. X-ray diffraction (XRD) indicated that the formed precipitates were composed of natrojarosite with schwertmannite when the initial pH was 3.51, while only schwertmannite was produced when initial pH was in the range of 1.60-3.44 and no precipitate occurred when initial pH {<=} 1.40. Scanning electron microscope (SEM) analyses showed that precipitates formed in solution with initial pH 3.51 were spherical particles of about 0.4 {mu}m in diameter and had a smooth surface, whereas precipitates in solution with initial pH {<=} 3.44 were spherical particles of approximately 1.0 {mu}m in diameter, having specific sea-urchin morphology. Specific surface area of the precipitates varied from 3.42 to 23.45 m{sup 2} g{sup -1}. X-ray fluorescence analyses revealed that schwertmannite formed in solution with initial pH in the range of 2.00-3.44 had similar elemental composition and could be expressed as Fe{sub 8}O{sub 8}(OH){sub 4.42}(SO{sub 4}){sub 1.79,} whereas Fe{sub 8}O{sub 8}(OH){sub 4.36}(SO{sub 4}){sub 1.82} and Fe{sub 8}O{sub 8}(OH){sub 4.29}(SO{sub 4}){sub 1.86} as its chemical formula when the initial pH was 1.80 and 1.60, respectively.

  1. Modelling of the diffusion of pollutants in the atmosphere under varying conditions in large cultivated regions

    International Nuclear Information System (INIS)

    Wueneke, C.D.; Schultz, H.

    1975-01-01

    The most important routines of a numerical code based on the particle-in-cell-method for calculating the transport and the turbulent dispersion of inert and radio-active pollutants in the atmosphere have been programmed and have been tested successfully on the CDC computer CYBER 73/76 of the Regional Computer Centre for Niedersachsen in Hanover. Compared to the Gaussian plume model such a numerical code based on the particle-in-cell-method offers several advantages for the computation of the diffusion under varying conditions in large cultivated regions. (orig.) [de

  2. Effect of environmental and cultural conditions on medium pH and explant growth performance of Douglas-fir (Pseudotsuga menziesii shoot cultures [version 2; referees: 2 approved

    Directory of Open Access Journals (Sweden)

    Chien-Chih Chen

    2015-05-01

    Full Text Available The medium pH level of plant tissue cultures has been shown to be essential to many aspects of explant development and growth. Sensitivity or tolerance of medium pH change in vitro varies according to specific requirements of individual species. The objectives of this study are to 1 determine medium pH change over time in storage conditions and with presence of explants, 2 evaluate the effects of medium pH change on explant growth performance and 3 assess the effects of adding a pH stabilizer, 2-(N-morpholinoethanesulfonic acid (MES that is commonly used in Douglas-fir micropropagation medium. Vegetative buds were collected in the spring before breaking dormancy from juvenile and mature donor trees for conducting these evaluations. Medium, with or without MES, was pre-adjusted to five pH levels before adding MES, agar and autoclaving. Medium pH changes and explant growth parameters were measured at eight different incubation times. Overall, MES provided a more stable medium pH, relative to starting pH values, under both light and dark storage conditions as well as with presence of explants. A general trend of decreasing medium pH over time was found comparing explants from juvenile and mature donor genotypes. Explant height and weight growth increased over time, but differ among explants from juvenile and mature donor genotypes. Our findings suggest that a 21-day subculture practice may best sustain medium freshness, medium pH level and desirable explant growth.

  3. Positive and negative variations in capacitive images for given defects under varying experimental conditions

    Science.gov (United States)

    Li, Chen; Yin, Xiaokang; Li, Zhen; Li, Wei; Chen, Guoming

    2018-04-01

    Capacitive imaging (CI) technique is a novel electromagnetic NDE technique. The Quasi-static electromagnetic field from the carefully designed electrode pair will vary when the electrical properties of the sample change, leading to the possibility of imaging. It is observed that for a given specimen, the targeted features appear as different variations in capacitive images under different experimental conditions. In some cases, even opposite variations occur, which brings confusion to indication interpretation. It is thus thought interesting to embark on investigations into the cause and effects of the negative variation phenomenon. In this work, the positive and negative variations were first explained from the measurement sensitivity distribution perspective. This was then followed by a detailed analysis using finite element models in COMSOL. A parametric experimental study on a glass fiber composite plate with artificial defects was then carried out to investigate how the experimental conditions affect the variation.

  4. Assessment of a surface-layer parameterization scheme in an atmospheric model for varying meteorological conditions

    Directory of Open Access Journals (Sweden)

    T. J. Anurose

    2014-06-01

    Full Text Available The performance of a surface-layer parameterization scheme in a high-resolution regional model (HRM is carried out by comparing the model-simulated sensible heat flux (H with the concurrent in situ measurements recorded at Thiruvananthapuram (8.5° N, 76.9° E, a coastal station in India. With a view to examining the role of atmospheric stability in conjunction with the roughness lengths in the determination of heat exchange coefficient (CH and H for varying meteorological conditions, the model simulations are repeated by assigning different values to the ratio of momentum and thermal roughness lengths (i.e. z0m/z0h in three distinct configurations of the surface-layer scheme designed for the present study. These three configurations resulted in differential behaviour for the varying meteorological conditions, which is attributed to the sensitivity of CH to the bulk Richardson number (RiB under extremely unstable, near-neutral and stable stratification of the atmosphere.

  5. Analysis of grain filling process to the varied meteorological conditions in winter wheat [Triticum aestivum] cultivars

    International Nuclear Information System (INIS)

    Inoue, K.; Nakazono, K.; Wakiyama, Y.

    2005-01-01

    This paper describes effects of varied meteorological conditions on the grain filling periods, stabilities of yield and quality of winter wheat cultivars with different maturity characteristics (cv. Ayahikari, Norin61, Bandowase, and Tsurupikari). In the field experiments, the meteorological treatments were made during the first heading time on 17 April 2001 and the middle heading time on 24 April 2000. Air temperature, global solar radiation and soil moisture were controlled using a rain shelter, cheesecloth and irrigation system. The growth speed and growth period of wheat grains varied among four winter wheat cultivars, depending on meteorological conditions. The growth speed increased within 1 8.4 deg C of mean air temperature over the 30 days after the anthesis. On the other hand, it was found that the growth speed of wheat grains and the maximum number of wheat grains (Ymax) decreased greatly with the 44.4% interception of global solar radiation. Logistic functions were fitted to the relationship between the relative thousand-kernel-weight (Y/Ymax) and the total integrated temperature (sigmaTa) after heading for all treatment conditions. The maximum weight of grains (Ymax) achieved at the harvest time varied somewhat clearly among four winter wheat cultivars and meteorological conditions. Multiple regression analysis showed that the grain yield (Ymax) of four wheat cultivars correlated positively with daily mean solar radiation. It was also found that the cultivar Ayahikari had a highly significant negative correlation between its grain weight and soil moisture. Namely, the grain weight of high soil moisture plot with pF=1.5 was lower by about 9% than that of a control plot with pF=3.5. On the other hand, the grain yield of cultivar Norin61 responded inversely to a wet environment, indicating that its grain weight was higher for high soil moisture and high wet-bulb temperature than for a dry environment. The grain yield of early varieties of Bandowase and

  6. Adsorption of diclofenac onto organoclays: Effects of surfactant and environmental (pH and temperature) conditions

    OpenAIRE

    De Oliveira , Tiago; Guégan , Régis; Thiebault , Thomas; Le Milbeau , Claude; Muller , Fabrice; Teixeira , Vinicius; Giovanela , Marcelo; Boussafir , Mohammed

    2017-01-01

    Accepted Manuscript; International audience; Among pharmaceutical products (PPs) recalcitrant to water treatments, diclofenac shows a high toxicity and remains at high concentration in natural aquatic environments. The aim of this study concerns the understanding of the adsorption mechanism of this anionic PP onto two organoclays prepared with two long-alkyl chains cationic surfactants showing different chemical nature for various experimental pH and temperature conditions. The experimental d...

  7. Basic regulatory principles of Escherichia coli's electron transport chain for varying oxygen conditions.

    Science.gov (United States)

    Henkel, Sebastian G; Ter Beek, Alexander; Steinsiek, Sonja; Stagge, Stefan; Bettenbrock, Katja; de Mattos, M Joost Teixeira; Sauter, Thomas; Sawodny, Oliver; Ederer, Michael

    2014-01-01

    For adaptation between anaerobic, micro-aerobic and aerobic conditions Escherichia coli's metabolism and in particular its electron transport chain (ETC) is highly regulated. Although it is known that the global transcriptional regulators FNR and ArcA are involved in oxygen response it is unclear how they interplay in the regulation of ETC enzymes under micro-aerobic chemostat conditions. Also, there are diverse results which and how quinones (oxidised/reduced, ubiquinone/other quinones) are controlling the ArcBA two-component system. In the following a mathematical model of the E. coli ETC linked to basic modules for substrate uptake, fermentation product excretion and biomass formation is introduced. The kinetic modelling focusses on regulatory principles of the ETC for varying oxygen conditions in glucose-limited continuous cultures. The model is based on the balance of electron donation (glucose) and acceptance (oxygen or other acceptors). Also, it is able to account for different chemostat conditions due to changed substrate concentrations and dilution rates. The parameter identification process is divided into an estimation and a validation step based on previously published and new experimental data. The model shows that experimentally observed, qualitatively different behaviour of the ubiquinone redox state and the ArcA activity profile in the micro-aerobic range for different experimental conditions can emerge from a single network structure. The network structure features a strong feed-forward effect from the FNR regulatory system to the ArcBA regulatory system via a common control of the dehydrogenases of the ETC. The model supports the hypothesis that ubiquinone but not ubiquinol plays a key role in determining the activity of ArcBA in a glucose-limited chemostat at micro-aerobic conditions.

  8. Mapping and simulating systematics due to spatially varying observing conditions in DES science verification data

    International Nuclear Information System (INIS)

    Leistedt, B.; Peiris, H. V.; Elsner, F.; Benoit-Lévy, A.; Amara, A.

    2016-01-01

    Spatially varying depth and the characteristics of observing conditions, such as seeing, airmass, or sky background, are major sources of systematic uncertainties in modern galaxy survey analyses, particularly in deep multi-epoch surveys. We present a framework to extract and project these sources of systematics onto the sky, and apply it to the Dark Energy Survey (DES) to map the observing conditions of the Science Verification (SV) data. The resulting distributions and maps of sources of systematics are used in several analyses of DES–SV to perform detailed null tests with the data, and also to incorporate systematics in survey simulations. We illustrate the complementary nature of these two approaches by comparing the SV data with BCC-UFig, a synthetic sky catalog generated by forward-modeling of the DES–SV images. We analyze the BCC-UFig simulation to construct galaxy samples mimicking those used in SV galaxy clustering studies. We show that the spatially varying survey depth imprinted in the observed galaxy densities and the redshift distributions of the SV data are successfully reproduced by the simulation and are well-captured by the maps of observing conditions. The combined use of the maps, the SV data, and the BCC-UFig simulation allows us to quantify the impact of spatial systematics on N(z), the redshift distributions inferred using photometric redshifts. We conclude that spatial systematics in the SV data are mainly due to seeing fluctuations and are under control in current clustering and weak-lensing analyses. However, they will need to be carefully characterized in upcoming phases of DES in order to avoid biasing the inferred cosmological results. Finally, the framework presented here is relevant to all multi-epoch surveys and will be essential for exploiting future surveys such as the Large Synoptic Survey Telescope, which will require detailed null tests and realistic end-to-end image simulations to correctly interpret the deep, high

  9. Testing the stability of magnetic iron oxides/kaolinite nanocomposite under various pH conditions

    Science.gov (United States)

    Tokarčíková, Michaela; Tokarský, Jonáš; Kutláková, Kateřina Mamulová; Seidlerová, Jana

    2017-09-01

    Magnetically modified clays containing iron oxides nanoparticles (FexOy NPs) are low-cost and environmentally harmless materials suitable for sorption of pollutants from wastewaters. Stability of this smart material was evaluated both experimentally and theoretically using molecular modelling. Original kaolinite and prepared FexOy/kaolinite nanocomposite were characterized using X-ray fluorescence spectroscopy, X-ray powder diffraction, infrared spectroscopy, and transmission electron microscopy, and the stability was studied using leaching tests performed according to the European technical standard EN 12457-2 in deionized water and extraction agents with varying pH (2, 4, 9, and 11). The influence of pH on amount of FexOy NPs released from the composite and amount of the basic elements released from the kaolinite structure was studied using inductively coupled plasma atomic emission spectroscopy. All experiments proved that the magnetic properties of the nanocomposite will not change even after leaching in extraction agents with various pH.

  10. Developments in the monitoring and control of Eh and pH conditions in hydrothermal experiments

    International Nuclear Information System (INIS)

    Myers, J.; Ulmer, G.C.; Grandstaff, D.E.; Brozdowski, R.; Danielson, M.J.; Koski, O.H.

    1984-01-01

    In the design of a high-level nuclear waste repository it is essential to obtain accurate groundwater Eh-pH data. Design considerations such as the choice of matrix for the waste form, type and dimensions of canister material, use of buffers, and type and amount of backfill would all benefit from an exact knowledge of oxidation potentials (Eh) and acidity levels (pH) of the groundwater. The Basalt Waste Isolation Project (BWIP) has initiated a research effort to develop sensors which can be mounted in autoclaves to provide constant monitoring of the Eh-pH conditions that exist during waste form/barrier material/groundwater hydrothermal interaction tests. Sensors must withstand temperatures up to 300 0 C and pressures up to 300 bars. This report considers Teflon hydrogen diffusion membranes and zirconia pH sensors. The development of these sensors represents a significant advance in the environmental monitoring of Eh and pH conditions at elevated temperatures and pressures

  11. Insulin at pH 2: structural analysis of the conditions promoting insulin fibre formation.

    Science.gov (United States)

    Whittingham, Jean L; Scott, David J; Chance, Karen; Wilson, Ashley; Finch, John; Brange, Jens; Guy Dodson, G

    2002-04-26

    When insulin solutions are subjected to acid, heat and agitation, the normal pattern of insulin assembly (dimers-->tetramers-->hexamers) is disrupted; the molecule undergoes conformational changes allowing it to follow an alternative aggregation pathway (via a monomeric species) leading to the formation of insoluble amyloid fibres. To investigate the effect of acid pH on the conformation and aggregation state of the protein, the crystal structure of human insulin at pH 2.1 has been determined to 1.6 A resolution. The structure reveals that the native fold is maintained at low pH, and that the molecule is still capable of forming dimers similar to those found in hexameric insulin structures at higher pH. Sulphate ions are incorporated into the molecule and the crystal lattice where they neutralise positive charges on the protein, stabilising its structure and facilitating crystallisation. The sulphate interactions are associated with local deformations in the protein, which may indicate that the structure is more plastic at low pH. Transmission electron microscopy analysis of insulin fibres reveals that the appearance of the fibres is greatly influenced by the type of acid employed. Sulphuric acid produces distinctive highly bunched, truncated fibres, suggesting that the sulphate ions have a sophisticated role to play in fibre formation, rather as they do in the crystal structure. Analytical ultracentrifugation studies show that in the absence of heating, insulin is predominantly dimeric in mineral acids, whereas in acetic acid the equilibrium is shifted towards the monomer. Hence, the effect of acid on the aggregation state of insulin is also complex. These results suggest that acid conditions increase the susceptibility of the molecule to conformational change and dissociation, and enhance the rate of fibrillation by providing a charged environment in which the attractive forces between the protein molecules is increased. (c) 2002 Elsevier Science Ltd.

  12. Detection and classification of alarm threshold violations in condition monitoring systems working in highly varying operational conditions

    Science.gov (United States)

    Strączkiewicz, M.; Barszcz, T.; Jabłoński, A.

    2015-07-01

    All commonly used condition monitoring systems (CMS) enable defining alarm thresholds that enhance efficient surveillance and maintenance of dynamic state of machinery. The thresholds are imposed on the measured values such as vibration-based indicators, temperature, pressure, etc. For complex machinery such as wind turbine (WT) the total number of thresholds might be counted in hundreds multiplied by the number of operational states. All the parameters vary not only due to possible machinery malfunctions, but also due to changes in operating conditions and these changes are typically much stronger than the former ones. Very often, such a behavior may lead to hundreds of false alarms. Therefore, authors propose a novel approach based on parameterized description of the threshold violation. For this purpose the novelty and severity factors are introduced. The first parameter refers to the time of violation occurrence while the second one describes the impact of the indicator-increase to the entire machine. Such approach increases reliability of the CMS by providing the operator with the most useful information of the system events. The idea of the procedure is presented on a simulated data similar to those from a wind turbine.

  13. Detection and classification of alarm threshold violations in condition monitoring systems working in highly varying operational conditions

    International Nuclear Information System (INIS)

    Strączkiewicz, M; Barszcz, T; Jabłoński, A

    2015-01-01

    All commonly used condition monitoring systems (CMS) enable defining alarm thresholds that enhance efficient surveillance and maintenance of dynamic state of machinery. The thresholds are imposed on the measured values such as vibration-based indicators, temperature, pressure, etc. For complex machinery such as wind turbine (WT) the total number of thresholds might be counted in hundreds multiplied by the number of operational states. All the parameters vary not only due to possible machinery malfunctions, but also due to changes in operating conditions and these changes are typically much stronger than the former ones. Very often, such a behavior may lead to hundreds of false alarms. Therefore, authors propose a novel approach based on parameterized description of the threshold violation. For this purpose the novelty and severity factors are introduced. The first parameter refers to the time of violation occurrence while the second one describes the impact of the indicator-increase to the entire machine. Such approach increases reliability of the CMS by providing the operator with the most useful information of the system events. The idea of the procedure is presented on a simulated data similar to those from a wind turbine. (paper)

  14. Influence of geometry of pipe on flow accelerated corrosion - a study under neutral pH condition

    International Nuclear Information System (INIS)

    Madasamy, P.; Mukunthan, M.; Chandramohan, P.; Krishna Mohan, T.V.; Velmurugan, S.; Sylvanus, Andrews; Natarajan, E.

    2015-01-01

    The carbon steel piping material's degradation due to flow accelerated corrosion (FAC) is one of the problems in nuclear power plant. FAC impacts plant operation and maintenance significantly. Wall thinning of structural materials should be predictable based on combined hydrodynamics analyses and experimental corrosion data. Such predictive tools help to take preventive measures before loss of material becomes a serious issue for plant operation. In order to develop predictive tools, data on the effect of various parameters that control FAC are required. As per existing literature, one of the important parameters that affect FAC is piping configuration (Geometry of flow path). Hence, experiments were carried out to assess the role played by the geometry of the piping in the FAC of carbon steel. In this study, experiments were conducted in simulation loop under neutral pH condition while varying the geometry parameter of bend such as bend angle and bend radius. Therefore, pipe specimen holder 15 NB bend with 58 °, 73 ° as bend angle and 4D, 2D bend radius was designed and fabricated. The experiments were carried out in order to quantify the wear rate (wall thickness measurement was by ultrasonic method) with a single phase flow velocity (7 m/s) under neutral pH conditions With the pipe specimen four experiments were conducted under neutral pH condition and at 120 DC. Wall thickness mapping was carried out by ultrasonic thickness gauge using a template before and after the experiment. High wall thickness reduction under neutral water chemistry enables easy measurement by ultrasonic thickness gauge. It was observed from the first two sets (2D 58°, 4D 58°) that the corrosion rate with 4D, 58 ° was 50% less than the corrosion with 2D 58°. Subsequently, another two sets of experiments (2D 73° and 4D 73°) was carried out in SIM loop at 7 m/s under neutral pH conditions for two months. Thus, this method of experiments enables us to understand the geometrical

  15. Clostridium tyrobutyricum strains show wide variation in growth at different NaCl, pH, and temperature conditions.

    Science.gov (United States)

    Ruusunen, Marjo; Surakka, Anu; Korkeala, Hannu; Lindström, Miia

    2012-10-01

    Outgrowth from Clostridium tyrobutyricum spores in milk can lead to butyric acid fermentation in cheeses, causing spoilage and economical loss to the dairy industry. The aim of this study was to investigate the growth of 10 C. tyrobutyricum strains at different NaCl, pH, and temperature conditions. Up to 7.5-fold differences among the maximum growth rates of different strains in the presence of 2.0% NaCl were observed. Five of 10 strains were able to grow in the presence of 3.0% NaCl, while a NaCl concentration of 3.5% was completely inhibitory to all strains. Seven of 10 strains were able to grow at pH 5.0, and up to 4- and 12.5-fold differences were observed among the maximum growth rates of different strains at pH 5.5 and 7.5, respectively. The maximum growth temperatures varied from 40.2 to 43.3°C. The temperature of 10°C inhibited the growth of all strains, while 8 of 10 strains grew at 12 and 15°C. Despite showing no growth, all strains were able to survive at 10°C. In conclusion, wide variation was observed among different C. tyrobutyricum strains in their ability to grow at different stressful conditions. Understanding the physiological diversity among the strains is important when designing food control measures and predictive models for the growth of spoilage organisms in cheese.

  16. pH dependent green synthesis of gold nanoparticles by completely C6-carboxylated curdlan under high temperature and various pH conditions.

    Science.gov (United States)

    Qiu, Wen-Yi; Wang, Kai; Wang, Yao-Yao; Ding, Zhi-Chao; Wu, Li-Xia; Cai, Wu-Dan; Yan, Jing-Kun

    2018-01-01

    A C6-carboxylated curdlan (C6-Cc) obtained from 4-acetamido-TEMPO-mediated oxidation of curdlan was used both as a reducing and stabilizing agent for green synthesis of pH-responsive AuNPs, which was carried out by controlling the pH of the C6-Cc solution at a high temperature (100°C). C6-Cc presented a semi-flexible random coil chain in the aqueous medium at pH 5.5 and became more expanded and rigid in alkaline conditions (pH 7.1-12.0), though the primary chemical structure of C6-Cc was virtually unchanged with the pH variation. The AuNPs prepared with C6-Cc at various pHs were characterized by various instrumental measurements. The shapes and sizes of AuNPs were found to be strongly dependent on the pH of the C6-Cc solution. The C6-Cc-decorated AuNPs exhibited a more well-dispersed spherical morphology with smaller particle sizes under alkaline conditions (pH 7.1-12.0). Through this study, a facile, simple, and green method has been demonstrated for preparation of stimuli-sensitive AuNPs using biocompatible polyanionic polysaccharides. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Risky behavior and its effect on survival: snowshoe hare behavior under varying moonlight conditions

    Science.gov (United States)

    Gigliotti, Laura C.; Diefenbach, Duane R.

    2018-01-01

    Predation and predation risk can exert strong influences on the behavior of prey species. However, risk avoidance behaviors may vary among populations of the same species. We studied a population of snowshoe hares (Lepus americanus) near the southern edge of their range, in Pennsylvania. This population occupies different habitat types, experiences different environmental conditions, and are exposed to different predator species and densities than northern hare populations; therefore, they might exhibit differences in risk avoidance behaviors. We analyzed hare survival, movement rates, and habitat use under different levels of predation risk, as indexed by moonlight. Similar to previous work, we found snowshoe hare survival decreased with increased moon illumination during the winter, but we found differences in behavioral responses to increased predation risk. We found that snowshoe hares did not reduce movement rates during high‐risk nights, but instead found that hares selected areas with denser canopy cover, compared to low‐risk nights. We suggest that behavioral plasticity in response to predation risk allows populations of the same species to respond to localized conditions.

  18. PERT: A Method for Expression Deconvolution of Human Blood Samples from Varied Microenvironmental and Developmental Conditions

    Science.gov (United States)

    Csaszar, Elizabeth; Yu, Mei; Morris, Quaid; Zandstra, Peter W.

    2012-01-01

    The cellular composition of heterogeneous samples can be predicted using an expression deconvolution algorithm to decompose their gene expression profiles based on pre-defined, reference gene expression profiles of the constituent populations in these samples. However, the expression profiles of the actual constituent populations are often perturbed from those of the reference profiles due to gene expression changes in cells associated with microenvironmental or developmental effects. Existing deconvolution algorithms do not account for these changes and give incorrect results when benchmarked against those measured by well-established flow cytometry, even after batch correction was applied. We introduce PERT, a new probabilistic expression deconvolution method that detects and accounts for a shared, multiplicative perturbation in the reference profiles when performing expression deconvolution. We applied PERT and three other state-of-the-art expression deconvolution methods to predict cell frequencies within heterogeneous human blood samples that were collected under several conditions (uncultured mono-nucleated and lineage-depleted cells, and culture-derived lineage-depleted cells). Only PERT's predicted proportions of the constituent populations matched those assigned by flow cytometry. Genes associated with cell cycle processes were highly enriched among those with the largest predicted expression changes between the cultured and uncultured conditions. We anticipate that PERT will be widely applicable to expression deconvolution strategies that use profiles from reference populations that vary from the corresponding constituent populations in cellular state but not cellular phenotypic identity. PMID:23284283

  19. Assessing the effects of adaptation measures on optimal water resources allocation under varied water availability conditions

    Science.gov (United States)

    Liu, Dedi; Guo, Shenglian; Shao, Quanxi; Liu, Pan; Xiong, Lihua; Wang, Le; Hong, Xingjun; Xu, Yao; Wang, Zhaoli

    2018-01-01

    Human activities and climate change have altered the spatial and temporal distribution of water availability which is a principal prerequisite for allocation of different water resources. In order to quantify the impacts of climate change and human activities on water availability and optimal allocation of water resources, hydrological models and optimal water resource allocation models should be integrated. Given that increasing human water demand and varying water availability conditions necessitate adaptation measures, we propose a framework to assess the effects of these measures on optimal allocation of water resources. The proposed model and framework were applied to a case study of the middle and lower reaches of the Hanjiang River Basin in China. Two representative concentration pathway (RCP) scenarios (RCP2.6 and RCP4.5) were employed to project future climate, and the Variable Infiltration Capacity (VIC) hydrological model was used to simulate the variability of flows under historical (1956-2011) and future (2012-2099) conditions. The water availability determined by simulating flow with the VIC hydrological model was used to establish the optimal water resources allocation model. The allocation results were derived under an extremely dry year (with an annual average water flow frequency of 95%), a very dry year (with an annual average water flow frequency of 90%), a dry year (with an annual average water flow frequency of 75%), and a normal year (with an annual average water flow frequency of 50%) during historical and future periods. The results show that the total available water resources in the study area and the inflow of the Danjiangkou Reservoir will increase in the future. However, the uneven distribution of water availability will cause water shortage problems, especially in the boundary areas. The effects of adaptation measures, including water saving, and dynamic control of flood limiting water levels (FLWLs) for reservoir operation, were

  20. Determination of the second virial coefficient of bovine serum albumin under varying pH and ionic strength by composition-gradient multi-angle static light scattering.

    Science.gov (United States)

    Ma, Yingfang; Acosta, Diana M; Whitney, Jon R; Podgornik, Rudolf; Steinmetz, Nicole F; French, Roger H; Parsegian, V Adrian

    2015-01-01

    Composition-gradient multi-angle static light scattering (CG-MALS) is an emerging technique for the determination of intermolecular interactions via the second virial coefficient B22. With CG-MALS, detailed studies of the second virial coefficient can be carried out more accurately and effectively than with traditional methods. In addition, automated mixing, delivery and measurement enable high speed, continuous, fluctuation-free sample delivery and accurate results. Using CG-MALS we measure the second virial coefficient of bovine serum albumin (BSA) in aqueous solutions at various values of pH and ionic strength of a univalent salt (NaCl). The systematic variation of the second virial coefficient as a function of pH and NaCl strength reveals the net charge change and the isoelectric point of BSA under different solution conditions. The magnitude of the second virial coefficient decreases to 1.13 x 10(-5) ml*mol/g(2) near the isoelectric point of pH 4.6 and 25 mM NaCl. These results illuminate the role of fundamental long-range electrostatic and van der Waals forces in protein-protein interactions, specifically their dependence on pH and ionic strength.

  1. pH control in the midgut of Aedesaegypti under different nutritional conditions.

    Science.gov (United States)

    Nepomuceno, Denise Barguil; Santos, Vânia Cristina; Araújo, Ricardo Nascimento; Pereira, Marcos Horácio; Sant'Anna, Maurício Roberto; Moreira, Luciano Andrade; Gontijo, Nelder Figueiredo

    2017-09-15

    Aedes aegypti is one of the most important disease vectors in the world. Because their gut is the first site of interaction with pathogens, it is important to understand A. aegypti gut physiology. In this study, we investigated the mechanisms of pH control in the midgut of A. aegypti females under different nutritional conditions. We found that unfed females have an acidic midgut (pH ∼6). The midgut of unfed insects is actively maintained at pH 6 regardless of the ingestion of either alkaline or acidic buffered solutions. V-ATPases are responsible for acidification after ingestion of alkaline solutions. In blood-fed females, the abdominal midgut becomes alkaline (pH 7.54), and the luminal pH decreases slightly throughout blood digestion. Only ingested proteins were able to trigger this abrupt increase in abdominal pH. The ingestion of amino acids, even at high concentrations, did not induce alkalinisation. During blood digestion, the thoracic midgut remains acidic, becoming a suitable compartment for carbohydrate digestion, which is in accordance with the higher alpha-glucolytic activity detected in this compartment. Ingestion of blood releases alkalising hormones in the haemolymph, which induce alkalinisation in ex vivo preparations. This study shows that adult A. aegypti females have a very similar gut physiology to that previously described for Lutzomyia longipalpis It is likely that all haematophagous Nematocera exhibit the same type of physiological behaviour. © 2017. Published by The Company of Biologists Ltd.

  2. Electrocatalytic hydrogen evolution under densely buffered neutral pH conditions

    KAUST Repository

    Shinagawa, Tatsuya

    2015-08-18

    Under buffered neutral pH conditions, solute concentrations drastically influence the hydrogen evolution reaction (HER). The iR-free HER performance as a function of solute concentration was found to exhibit a volcano-shaped trend in sodium phosphate solution at pH 5, with the maximum occurring at 2 M. A detailed microkinetic model that includes calculated activity coefficients, solution resistance, and mass-transport parameters accurately describes the measured values, clarifying that the overall HER performance is predominantly governed by mass-transport of slow phosphate ions (weak acid). In the HER at the optimum concentration of approximately 2 M sodium phosphate at pH 5, our theoretical model predicts that the concentration overpotential accounts for more than half of the required overpotential. The substantial concentration overpotential would originate from the electrolyte property, suggesting that the proper electrolyte engineering will result in an improved apparent HER performances. The significance of concentration overpotential shown in the study is critical in the advancement of electrocatalysis, biocatalysis, and photocatalysis.

  3. Electrocatalytic hydrogen evolution under densely buffered neutral pH conditions

    KAUST Repository

    Shinagawa, Tatsuya; Takanabe, Kazuhiro

    2015-01-01

    Under buffered neutral pH conditions, solute concentrations drastically influence the hydrogen evolution reaction (HER). The iR-free HER performance as a function of solute concentration was found to exhibit a volcano-shaped trend in sodium phosphate solution at pH 5, with the maximum occurring at 2 M. A detailed microkinetic model that includes calculated activity coefficients, solution resistance, and mass-transport parameters accurately describes the measured values, clarifying that the overall HER performance is predominantly governed by mass-transport of slow phosphate ions (weak acid). In the HER at the optimum concentration of approximately 2 M sodium phosphate at pH 5, our theoretical model predicts that the concentration overpotential accounts for more than half of the required overpotential. The substantial concentration overpotential would originate from the electrolyte property, suggesting that the proper electrolyte engineering will result in an improved apparent HER performances. The significance of concentration overpotential shown in the study is critical in the advancement of electrocatalysis, biocatalysis, and photocatalysis.

  4. Continuous biohydrogen production from fruit wastewater at low pH conditions.

    Science.gov (United States)

    Diamantis, Vasileios; Khan, Abid; Ntougias, Spyridon; Stamatelatou, Katerina; Kapagiannidis, Anastasios G; Aivasidis, Alexander

    2013-07-01

    Biohydrogen production from a simulated fruit wastewater (soluble COD = 3.17 ± 0.10 g L⁻¹) was carried out in a continuous stirred tank reactor (CSTR) of 2 L operational volume without biomass inoculation, heat pre-treatment or pH adjustment, resulting in a low operational pH (3.75 ± 0.09). The hydraulic retention time (HRT) varied from 15 to 5 h. A strong negative correlation (p CSTR was operated under the same HRT. The biogas hydrogen content was estimated as high as 55.8 ± 2.3 % and 55.4 ± 2.5 % at 25 and 30 °C, respectively. The main fermentation end products were acetic and butyric acids, followed by ethanol. Significant differences (p CSTR at 25 or 30 °C were identified for butyric acid at almost all HRTs examined. Simulation of the acidogenesis process in the CSTR (based on COD and carbon balances) indicated the possible metabolic compounds produced at 25 and 30 °C reactions and provided an adequate fit of the experimental data.

  5. Genome-wide transcriptome analysis of soybean primary root under varying water-deficit conditions.

    Science.gov (United States)

    Song, Li; Prince, Silvas; Valliyodan, Babu; Joshi, Trupti; Maldonado dos Santos, Joao V; Wang, Jiaojiao; Lin, Li; Wan, Jinrong; Wang, Yongqin; Xu, Dong; Nguyen, Henry T

    2016-01-15

    Soybean is a major crop that provides an important source of protein and oil to humans and animals, but its production can be dramatically decreased by the occurrence of drought stress. Soybeans can survive drought stress if there is a robust and deep root system at the early vegetative growth stage. However, little is known about the genome-wide molecular mechanisms contributing to soybean root system architecture. This study was performed to gain knowledge on transcriptome changes and related molecular mechanisms contributing to soybean root development under water limited conditions. The soybean Williams 82 genotype was subjected to very mild stress (VMS), mild stress (MS) and severe stress (SS) conditions, as well as recovery from the severe stress after re-watering (SR). In total, 6,609 genes in the roots showed differential expression patterns in response to different water-deficit stress levels. Genes involved in hormone (Auxin/Ethylene), carbohydrate, and cell wall-related metabolism (XTH/lipid/flavonoids/lignin) pathways were differentially regulated in the soybean root system. Several transcription factors (TFs) regulating root growth and responses under varying water-deficit conditions were identified and the expression patterns of six TFs were found to be common across the stress levels. Further analysis on the whole plant level led to the finding of tissue-specific or water-deficit levels specific regulation of transcription factors. Analysis of the over-represented motif of different gene groups revealed several new cis-elements associated with different levels of water deficit. The expression patterns of 18 genes were confirmed byquantitative reverse transcription polymerase chain reaction method and demonstrated the accuracy and effectiveness of RNA-Seq. The primary root specific transcriptome in soybean can enable a better understanding of the root response to water deficit conditions. The genes detected in root tissues that were associated with

  6. Phytoremdiation Species And Their Modification Under By Weed Varying Climatic Condition A Changing Scenario

    Directory of Open Access Journals (Sweden)

    Anita Singh

    2015-08-01

    Full Text Available Abstract The major reasons for environmental contamination are population explosion increase in industrial and other urban activities. One of the consequent effect of these activities is heavy metal pollution. It is one of the serious issue to be discussed by the scientists and academicians that how to solve this problem to protect the environment. As heavy metals are non-biodegradable so they require effective cleanup technology. Most of the traditional methods such as excavation solidification and burial are very costly or they simply involve the isolation of the metals from contaminated sites. Among different technologies phytoremediation is best approach for removing metal contamination from environment. It involves plants to remove detoxify or immobilize metals from environment. Weed plants are found to be play very important role in metal remediation. They get affected by climatic variation which is also a consequent effect of environmental pollution. The physiology of plants as well as physiochemical properties of soil gets affected by varying climatic condition. Therefore the present review gives the information on metal remediation processes and how these process particularly phytoremediation by weed plants get affected by climatic changes.

  7. Asymmetric Vibration of Polar Orthotropic Annular Circular Plates of Quadratically Varying Thickness with Same Boundary Conditions

    Directory of Open Access Journals (Sweden)

    N. Bhardwaj

    2008-01-01

    Full Text Available In the present paper, asymmetric vibration of polar orthotropic annular circular plates of quadratically varying thickness resting on Winkler elastic foundation is studied by using boundary characteristic orthonormal polynomials in Rayleigh-Ritz method. Convergence of the results is tested and comparison is made with results already available in the existing literature. Numerical results for the first ten frequencies for various values of parameters describing width of annular plate, thickness profile, material orthotropy and foundation constant for all three possible combinations of clamped, simply supported and free edge conditions are shown and discussed. It is found that (a higher elastic property in circumferential direction leads to higher stiffness against lateral vibration; (b Lateral vibration characteristics of F-Fplates is more sensitive towards parametric changes in material orthotropy and foundation stiffness than C-C and S-Splates; (c Effect of quadratical thickness variation on fundamental frequency is more significant in cases of C-C and S-S plates than that of F-Fplates. Thickness profile which is convex relative to plate center-line tends to result in higher stiffness of annular plates against lateral vibration than the one which is concave and (d Fundamental mode of vibration of C-C and S-Splates is axisymmetrical while that of F-Fplates is asymmetrical.

  8. Heavy metals in precipitation waters under conditions of varied anthropopressure in typical of European low mountain regions

    Directory of Open Access Journals (Sweden)

    Rabajczyk A.

    2013-04-01

    Full Text Available The environment is a dynamic system, subject to change resulting from a variety of physicochemical factors, such as temperature, pressure, pH, redox potential and human activity. The quantity and variety of these determinants cause the inflow of substances into individual environmental elements to vary in both time and space, as well as in terms of substance types and quantities. The energy and matter flow in the environment determines its integrity, which means that the processes occurring in one element of the environment affect the others. A certain measure of the energy and matter flow is the migration of chemical substances in various forms from one place to another. In a particular geographical space, under natural conditions, a specific level of balance between individual processes appears; in areas subject to anthropopressure, the correlations are different. In small areas, varying deposition volumes and chemism of precipitation waters which reach the substratum directly can both be observed. The study area is similar in terms of geological origins as well as morphological, structural and physico-chemical properties, and is typical of European low mountain regions. A qualitative and quantitative study of wet atmospheric precipitation was conducted between February 2009 and May 2011 in the Bobrza river catchment in the Holy Cross (Świętokrzyskie Mountains (Poland, at three sampling sites of varying land development and distance from sources of various acidic-alkaline emissions. Field and laboratory work was conducted over 29 months, from February 2009 to May 2011. Atmospheric precipitation measurements were carried out in a continuous manner by means of a Hellman rain gauge (200cm2. The collecting surface was placed at ground level (0m AGL. The application of a collecting funnel and an adequately prepared polyethylene collecting can in the rain gauge enabled the measurement of precipitation volume and water sampling for chemical

  9. The influence of spatially and temporally varying oceanographic conditions on meroplanktonic metapopulations

    Science.gov (United States)

    Botsford, L. W.; Moloney, C. L.; Hastings, A.; Largier, J. L.; Powell, T. M.; Higgins, K.; Quinn, J. F.

    We synthesize the results of several modelling studies that address the influence of variability in larval transport and survival on the dynamics of marine metapopulations distributed along a coast. Two important benthic invertebrates in the California Current System (CCS), the Dungeness crab and the red sea urchin, are used as examples of the way in which physical oceanographic conditions can influence stability, synchrony and persistence of meroplanktonic metapopulations. We first explore population dynamics of subpopulations and metapopulations. Even without environmental forcing, isolated local subpopulations with density-dependence can vary on time scales roughly twice the generation time at high adult survival, shifting to annual time scales at low survivals. The high frequency behavior is not seen in models of the Dungeness crab, because of their high adult survival rates. Metapopulations with density-dependent recruitment and deterministic larval dispersal fluctuate in an asynchronous fashion. Along the coast, abundance varies on spatial scales which increase with dispersal distance. Coastwide, synchronous, random environmental variability tends to synchronize these metapopulations. Climate change could cause a long-term increase or decrease in mean larval survival, which in this model leads to greater synchrony or extinction respectively. Spatially managed metapopulations of red sea urchins go extinct when distances between harvest refugia become greater than the scale of larval dispersal. All assessments of population dynamics indicate that metapopulation behavior in general dependes critically on the temporal and spatial nature of larval dispersal, which is largely determined by physical oceanographic conditions. We therfore explore physical influences on larval dispersal patterns. Observed trends in temperature and salinity applied to laboratory-determined responses indicate that natural variability in temperature and salinity can lead to variability in

  10. Effect of Varying Acid Hydrolysis Condition in Gracilaria Sp. Fermentation Using Sasad

    Science.gov (United States)

    Mansuit, H.; Samsuri, M. D. C.; Sipaut, C. S.; Yee, C. F.; Yasir, S. M.; Mansa, R.

    2015-04-01

    Macroalgae or seaweed is being considered as promising feedstock for bioalcohol production due to high polysaccharides content. Polysaccharides can be converted into fermentable sugar through acid hydrolysis pre-treatment. In this study, the potential of using carbohydrate-rich macroalgae, Gracilaria sp. as feedstock for bioalcohol production via various acid hydrolysis conditions prior to the fermentation process was investigated and evaluated. The seaweed used in this research was from the red algae group, using species of Gracilaria sp. which was collected from Sg. Petani Kedah, Malaysia. Pre-treatment of substrate was done using H2SO4 and HCl with molarity ranging from 0.2M to 0.8M. The pretreatment time were varied in the range of 15 to 30 minutes. Fermentation was conducted using Sasad, a local Sabahan fermentation agent as a starter culture. Alcohol extraction was done using a distillation unit. Reducing sugar analysis was done by Benedict test method. Alcohol content analysis was done using specific gravity test. After hydrolysis, it was found out that acid hydrolysis at 0.2M H2SO4 and pre-treated for 20 minutes at 121°C has shown the highest reducing sugar content which has yield (10.06 mg/g) of reducing sugar. It was followed by other samples hydrolysis using 0.4M HCl with 30 minutes pre-treatment and 0.2M H2SO4, 15 minutes pre-treatment with yield of 8.06 mg/g and 5.75 mg/g reducing sugar content respectively. In conclusion, acid hydrolysis of Gracilaria sp. can produce higher reducing sugar yield and thus it can further enhance the bioalcohol production yield. Hence, acid hydrolysis of Gracilaria sp. should be studied more as it is an important step in the bioalcohol production and upscaling process.

  11. Multi-Fibre Optode Microsensors: affordable designs for monitoring oxygen in soils under varying environmental conditions

    Science.gov (United States)

    Rezanezhad, F.; Milojevic, T.; Parsons, C. T.; Smeaton, C. M.; Van Cappellen, P.

    2017-12-01

    , where the imaged data is transmitted remotely using a photo-logging system. The MuFO sensor is currently being tested at a Southern Ontario field site in a year-long experiment. Here we present the field and laboratory results of soil O2 monitoring by this newly developed MuFO microsensor system under varying environmental conditions.

  12. Conformational Plasticity of the Influenza A M2 Transmembrane Helix in Lipid Bilayers Under Varying pH, Drug Binding and Membrane Thickness

    Science.gov (United States)

    Hu, Fanghao; Luo, Wenbin; Cady, Sarah D.; Hong, Mei

    2010-01-01

    Membrane proteins change their conformations to respond to environmental cues, thus conformational plasticity is important for function. The influenza A M2 protein forms an acid-activated proton channel important for the virus lifecycle. Here we have used solid-state NMR spectroscopy to examine the conformational plasticity of membrane-bound transmembrane domain of M2 (M2TM). 13C and 15N chemical shifts indicate coupled conformational changes of several pore-facing residues due to changes in bilayer thickness, drug binding and pH. The structural changes are attributed to the formation of a well-defined helical kink at G34 in the drug-bound state and in thick lipid bilayers, non-ideal backbone conformation of the secondary-gate residue V27 in the presence of drug, and non-ideal conformation of the proton-sensing residue H37 at high pH. The chemical shifts constrained the (ϕ, ψ) torsion angles for three basis states, the equilibrium among which explains the multiple resonances per site in the NMR spectra under different combinations of bilayer thickness, drug binding and pH conditions. Thus, conformational plasticity is important for the proton conduction and inhibition of M2TM. The study illustrates the utility of NMR chemical shifts for probing the structural plasticity and folding of membrane proteins. PMID:20883664

  13. The effect of emulsifying salts on the turbidity of a diluted milk system with varying pH and protein concentration.

    Science.gov (United States)

    Culler, M D; Saricay, Y; Harte, F M

    2017-06-01

    Solutions of 10 commonly used emulsifying salts (ES) listed in the Code of Federal Regulations (21CFR133.179) for pasteurized process cheese were tested for their effect on the turbidity of a diluted milk system at different pH and protein concentrations to characterize the conditions that affect micellar structure. Emulsifying salt solutions were made by mixing the ES in a 1-in-20 dilution of water in skim milk ultrafiltrate (3 kDa molecular weight cut-off) to obtain ES concentrations from 0 to 248 mM. Skim milk was added to solutions containing nanopure water, skim milk ultrafiltrate, and a specific ES ranging in concentration from 0 to 248 mM and pH 5, 5.8, 6.8, 7.8, and 8.8. The turbidity of the samples was measured as the optical density at 400 nm immediately after mixing (time, t = 0), after 30 s (t = 30s), and after 30 min (t = 30min). Emulsifying salts were found to cause a decrease in the turbidity of the system, which was modeled using an exponential decay model, where C* represents a threshold salt concentration at which rapid dissociation occurs. At pH values 5.8 and 6.8, the ES caused the greatest decrease in turbidity of the diluted milk system. At pH 5, the ES had the least effect on the turbidity of the system. Sodium hexametaphosphate was found to have the strongest dissociative effect, with a C* value of 0.33 mM for t = 0 at pH 6.8. In contrast, the largest C* value calculated at pH 6.8 was monosodium phosphate at 278.22 mM. Increased time resulted in lower C* values. The model established for this study can be used to predict the dissociation of casein micelles in the presence of various types of ES. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  14. Attenuation of organic micropollutants in an urban lowland stream under varying seasonal and hydrological conditions

    Science.gov (United States)

    Jaeger, Anna; Posselt, Malte; Schaper, Jonas; Lewandowski, Jörg

    2017-04-01

    Transport and fate of polar organic micropollutants in urban streams are of increasing concern for urban water management. Appropriate river management techniques may support a river's ability to self-purify. The river Erpe, an urban lowland stream located in Berlin, Germany, receives treated wastewater which increases its discharge up to 4-fold. Numerous micropollutants (e.g. pharmaceuticals, personal care products, performance chemicals) which survive the treatment process are released into the river and threaten ecosystems and aquatic groundwater quality. In the present work the transport of 57 substances was investigated along a 4.7 km stretch of the river with the aim of understanding the influence of varying seasonal and hydrological conditions on micropollutant fate. We hypothesized that particularly transient storage is a main driver of micropollutant attenuation. A Lagrangian sampling scheme was applied to follow water parcels down the river using the diurnal fluctuations of conservative solute concentrations as an intrinsic tracer. Water samples were collected at two (April) and three (June) stations along a 4.7 km reach downstream of the wastewater inflow. In June the experiment was conducted twice, before and after the first stretch was cleared of macrophytes. Each experiment comprised of hourly sample collection for 48 hours, accompanied by discharge measurements and continuous data logging of water-level, -temperature and electric conductivity. The set of micropollutants, which included both parent compounds and transformation products, was analysed by a newly developed direct injection-UHPLC-MS/MS method. The behaviour of individual micropollutants was compound-specific. Carbamazepine and benzotriazole were persistent along the river stretch while substances such as valsartan and metoprolol were attenuated by up to 15% of their original concentration. Interestingly, some transformation products, such as valsartan acid increased in concentration

  15. Effect of Varying Hemodynamic and Vascular Conditions on Fractional Flow Reserve: An In Vitro Study.

    Science.gov (United States)

    Kolli, Kranthi K; Min, James K; Ha, Seongmin; Soohoo, Hilary; Xiong, Guanglei

    2016-06-30

    The aim of this study was to investigate the impact of varying hemodynamic conditions on fractional flow reserve (ratio of pressure distal [Pd] and proximal [Pa] to stenosis under hyperemia) in an in vitro setting. Failure to achieve maximal hyperemia and the choice of hyperemic agents may have differential effects on coronary hemodynamics and, consequently, on the determination of fractional flow reserve. An in vitro flow system was developed to experimentally model the physiological coronary circulation as flow-dependent stenosis resistance in series with variable downstream resistance. Five idealized models with 30% to 70% diameter stenosis severity were fabricated using VeroClear rigid material in an Objet260 Connex printer. Mean aortic pressure was maintained at 7 levels (60-140 mm Hg) from hypotension to hypertension using a needle valve that mimicked adjustable microcirculatory resistance. A range of physiological flow rates was applied by a steady flow pump and titrated by a flow sensor. The pressure drop and the pressure ratio (Pd/Pa) were assessed for the 7 levels of aortic pressure and differing flow rates. The in vitro experimental data were coupled with pressure-flow relationships from clinical data for populations with and without myocardial infarction, respectively, to evaluate fractional flow reserve. The curve for pressure ratio and flow rate demonstrated a quadratic relationship with a decreasing slope. The absolute decrease in fractional flow reserve in the group without myocardial infarction (with myocardial infarction) was on the order of 0.03 (0.02), 0.05 (0.02), 0.07 (0.05), 0.17 (0.13) and 0.20 (0.24), respectively, for 30%, 40%, 50%, 60%, and 70% diameter stenosis, for an increase in aortic pressure from 60 to 140 mm Hg. The fractional flow reserve value, an index of physiological stenosis significance, was observed to decrease with increasing aortic pressure for a given stenosis in this idealized in vitro experiment for vascular

  16. Volatility spillover and time-varying conditional correlation between DDGS, corn, and soybean meal markets

    NARCIS (Netherlands)

    Etienne, Xiaoli L.; Trujillo-Barrera, Andrés; Hoffman, Linwood A.

    2017-01-01

    We find distiller's dried grains with solubles (DDGS) prices to be positively correlated with both corn and soybean meal prices in the long run. However, neither corn nor soybean meal prices respond to deviations from this long-run relationship. We also identify strong time-varying dynamic

  17. Sensitive detection of strong acidic condition by a novel rhodamine-based fluorescent pH chemosensor.

    Science.gov (United States)

    Tan, Jia-Lian; Yang, Ting-Ting; Liu, Yu; Zhang, Xue; Cheng, Shu-Jin; Zuo, Hua; He, Huawei

    2016-05-01

    A novel rhodamine-based fluorescent pH probe responding to extremely low pH values has been synthesized and characterized. This probe showed an excellent photophysical response to pH on the basis that the colorless spirocyclic structure under basic conditions opened to a colored and highly fluorescent form under extreme acidity. The quantitative relationship between fluorescence intensity and pH value (1.75-2.62) was consistent with the equilibrium equation pH = pKa + log[(Imax - I)/(I - Imin)]. This sensitive pH probe was also characterized with good reversibility and no interaction with interfering metal ions, and was successfully applied to image Escherichia coli under strong acidity. Copyright © 2015 John Wiley & Sons, Ltd.

  18. Emulsion properties of pork myofibrillar protein in combination with microbial transglutaminase and calcium alginate under various pH conditions.

    Science.gov (United States)

    Hong, Geun Pyo; Min, Sang-Gi; Chin, Koo Bok

    2012-01-01

    In this study, the effects of microbial transglutaminase (MTG) and calcium alginate (CA) systems in combination with soybean oil on the emulsion properties of porcine myofibrillar protein (MP) were evaluated under various pH conditions. MTG was shown to improve emulsifying capacity and creaming stability, which increased with increasing pH values up to 6.5. The CA did not influence emulsifying capacity, but it improved the creaming stability of the MP-stabilized emulsions. Both MTG and CA enhanced the rheological properties, but their effects on the physical characteristics of the protein evidenced an opposite trend in relation to pH, i.e., the MTG system improved both the emulsion and gelling properties with increasing pH, whereas the CA system was effective when the pH was lowered. By combining the two MP gelling systems, a stable and pH-insensible emulsion could be produced. Copyright © 2011 Elsevier Ltd. All rights reserved.

  19. Estimating time-varying conditional correlations between stock and foreign exchange markets

    Science.gov (United States)

    Tastan, Hüseyin

    2006-02-01

    This study explores the dynamic interaction between stock market returns and changes in nominal exchange rates. Many financial variables are known to exhibit fat tails and autoregressive variance structure. It is well-known that unconditional covariance and correlation coefficients also vary significantly over time and multivariate generalized autoregressive model (MGARCH) is able to capture the time-varying variance-covariance matrix for stock market returns and changes in exchange rates. The model is applied to daily Euro-Dollar exchange rates and two stock market indexes from the US economy: Dow-Jones Industrial Average Index and S&P500 Index. The news impact surfaces are also drawn based on the model estimates to see the effects of idiosyncratic shocks in respective markets.

  20. The sensitivity of particle pH to NH3: Can high NH3 cause London Fog conditions?

    Science.gov (United States)

    Weber, R. J.; Guo, H.; Nenes, A.

    2017-12-01

    High ammonia emissions from agriculture or other sources have been suggested to elevate ambient particle pH levels to near neutral acidity (pH=7), a condition that promotes rapid SO2 oxidation by NO2 to form aerosol sulfate concentration consistent with "London fog" levels. This mechanism has been used to explain pollution haze events in China. Predicted pH for locations in the US and Europe show fine particles are highly acidic with pH typically less than 2. The results are consistent with measured ammonia and nitric acid gas-particle partitioning, validating predicted pH levels. Using these data sets from representative sites around the world we conduct a thermodynamic analysis of aerosol pH and its sensitivity to ammonia levels. We find that particle pH, regardless of ammonia levels, is always acidic even for the unusually high ammonia levels found in highly polluted Asian cities, Beijing (pH=4.5) and Xi'an (pH=5), locations where sulfate production from NOx is proposed. These results indicate that sulfur dioxide oxidation through a NO2-mediated pathway is not likely in China, nor any other region of the world (e.g., US, Mediterranean) since the fine aerosol is consistently acidic. The mildly acidic conditions would, however, permit rapid oxidation of sulfur dioxide through transition metal chemistry. The limited alkalinity from the carbonate buffer in dust and seasalt can provide the only likely set of conditions where NO2-mediated oxidation of SO2 outcompetes with other well-established pathways.

  1. Optimization of hydrostatic pressure at varied sonication conditions--power density, intensity, very low frequency--for isothermal ultrasonic sludge treatment.

    Science.gov (United States)

    Delmas, Henri; Le, Ngoc Tuan; Barthe, Laurie; Julcour-Lebigue, Carine

    2015-07-01

    This work aims at investigating for the first time the key sonication (US) parameters: power density (DUS), intensity (IUS), and frequency (FS) - down to audible range, under varied hydrostatic pressure (Ph) and low temperature isothermal conditions (to avoid any thermal effect). The selected application was activated sludge disintegration, a major industrial US process. For a rational approach all comparisons were made at same specific energy input (ES, US energy per solid weight) which is also the relevant economic criterion. The decoupling of power density and intensity was obtained by either changing the sludge volume or most often by changing probe diameter, all other characteristics being unchanged. Comprehensive results were obtained by varying the hydrostatic pressure at given power density and intensity. In all cases marked maxima of sludge disintegration appeared at optimum pressures, which values increased at increasing power intensity and density. Such optimum was expected due to opposite effects of increasing hydrostatic pressure: higher cavitation threshold then smaller and fewer bubbles, but higher temperature and pressure at the end of collapse. In addition the first attempt to lower US frequency down to audible range was very successful: at any operation condition (DUS, IUS, Ph, sludge concentration and type) higher sludge disintegration was obtained at 12 kHz than at 20 kHz. The same values of optimum pressure were observed at 12 and 20 kHz. At same energy consumption the best conditions - obtained at 12 kHz, maximum power density 720 W/L and 3.25 bar - provided about 100% improvement with respect to usual conditions (1 bar, 20 kHz). Important energy savings and equipment size reduction may then be expected. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. THE PREDICTION OF pH BY GIBBS FREE ENERGY MINIMIZATION IN THE SUMP SOLUTION UNDER LOCA CONDITION OF PWR

    Directory of Open Access Journals (Sweden)

    HYOUNGJU YOON

    2013-02-01

    Full Text Available It is required that the pH of the sump solution should be above 7.0 to retain iodine in a liquid phase and be within the material compatibility constraints under LOCA condition of PWR. The pH of the sump solution can be determined by conventional chemical equilibrium constants or by the minimization of Gibbs free energy. The latter method developed as a computer code called SOLGASMIX-PV is more convenient than the former since various chemical components can be easily treated under LOCA conditions. In this study, SOLGASMIX-PV code was modified to accommodate the acidic and basic materials produced by radiolysis reactions and to calculate the pH of the sump solution. When the computed pH was compared with measured by the ORNL experiment to verify the reliability of the modified code, the error between two values was within 0.3 pH. Finally, two cases of calculation were performed for the SKN 3&4 and UCN 1&2. As results, pH of the sump solution for the SKN 3&4 was between 7.02 and 7.45, and for the UCN 1&2 plant between 8.07 and 9.41. Furthermore, it was found that the radiolysis reactions have insignificant effects on pH because the relative concentrations of HCl, HNO3, and Cs are very low.

  3. PIXE analysis of mineral composition of alfalfa root-tip exposed to low pH or aluminum stress condition

    International Nuclear Information System (INIS)

    Yokota, Satoshi; Mae, Tadahiko; Ojima, Kunihiko; Ishii, Keizo.

    1994-01-01

    PIXE analysis was applied to study alteration of mineral composition (Al, P, K, and Cl) of alfalfa root-tip exposed to low pH or aluminum stress. These minerals were detectable using one or two pieces of root-tips. Short-term (within 4 h) decreases in K/P and Cl/P ratios were observed under low pH and aluminum stress conditions. However, degree of the decrease was not same. Differences in toxic effects of low pH and Al on the root-tip of alfalfa are discussed. (author)

  4. "On-off-on" switchable sensor: a fluorescent spiropyran responds to extreme pH conditions and its bioimaging applications.

    Science.gov (United States)

    Wan, Shulin; Zheng, Yang; Shen, Jie; Yang, Wantai; Yin, Meizhen

    2014-11-26

    A novel spiropyran that responds to both extreme acid and extreme alkali and has an "on-off-on" switch is reported. Benzoic acid at the indole N-position and carboxyl group at the indole 6-position contribute to the extreme acid response. The ionizations of carboxyl and phenolic hydroxyl groups cause the extreme alkali response. Moreover, the fluorescent imaging in bacterial cells under extreme pH conditions supports the mechanism of pH response.

  5. Linear parameter varying control of wind turbines covering both partial load and full load conditions

    DEFF Research Database (Denmark)

    Østergaard, Kasper Zinck; Stoustrup, Jakob; Brath, Per

    2009-01-01

    operations tend to be ill-conditioned. The paper proposes a controller construction algorithm together with various remedies for improving the numerical conditioning the algorithm.The proposed algorithm is applied to the design of a LPV controller for wind turbines, and a comparison is made with a controller...... designed using classical techniques to conclude that an improvement in performance is obtained for the entire operating envelope....

  6. Numerical simulation of diurnally varying thermal environment in a street canyon under haze-fog conditions

    Science.gov (United States)

    Tan, Zijing; Dong, Jingliang; Xiao, Yimin; Tu, Jiyuan

    2015-10-01

    The impact of haze-fog on surface temperature, flow pattern, pollutant dispersion and pedestrian thermal comfort are investigated using computational fluid dynamics (CFD) approach based on a three-dimensional street canyon model under different haze-fog conditions. In this study, light extinction coefficient (Kex) is adopted to represent haze-fog pollution level. Numerical simulations are performed for different Kex values at four representative time events (1000 LST, 1300 LST, 1600 LST and 2000 LST). The numerical results suggest that the surface temperature is strongly affected by the haze-fog condition. Surface heating induced by the solar radiation is enhanced by haze-fog, as higher surface temperature is observed under thicker haze-fog condition. Moreover, the temperature difference between sunlit and shadow surfaces is reduced, while that for the two shadow surfaces is slightly increased. Therefore, the surface temperature among street canyon facets becomes more evenly distributed under heavy haze-fog conditions. In addition, flow patterns are considerably altered by different haze-fog conditions, especially for the afternoon (1600 LST) case, in which thermal-driven flow has opposite direction as that of the wind-driven flow direction. Consequently, pollutants such as vehicular emissions will accumulate at pedestrian level, and pedestrian thermal comfort may lower under thicker haze-fog condition.

  7. Adaptive observer-based control for an IPMC actuator under varying humidity conditions

    Science.gov (United States)

    Bernat, Jakub; Kolota, Jakub

    2018-05-01

    As ionic polymer metal composites (IPMC) are increasingly applied to mechatronic systems, many new IPMC modeling efforts have been reported in the literature. The demands of rapidly growing technology has generated interest in advancing the intrinsic actuation and sensing capabilities of IPMC. Classical IPMC applications need constant hydration to operate. On the other hand, for IPMCs operating in air, the water content of the polymer varies with the humidity level of the ambient environment, which leads to its strong humidity-dependent behavior. Furthermore, decreasing water content over time plays a crucial role in the effectiveness of IPMC. Therefore, the primary challenge of this work is to accurately model this phenomenon. The principal contribution of the paper is a new IPMC model, which considers the change of moisture content. A novel nonlinear adaptive observer is designed to determine the unknown electric potential and humidity level in the polymer membrane. This approach effectively determines the moisture content of the IPMC during long-term continuous operation in air. This subsequently allows us to develop an effective back-stepping control algorithm that considers varying moisture content. Data from experiments are presented to support the effectiveness of the observation process, which is shown in illustrative examples.

  8. The dissolution rate constant of magnetite in water at different temperatures and pH conditions

    International Nuclear Information System (INIS)

    Mohajery, Khatereh; Deydier de Pierrefeu, Laurent; Lister, Derek H.

    2012-09-01

    chemistry. For most determinations, a jet of water conditioned to the required chemistry but stripped of dissolved iron with ion-exchange is directed onto a pellet of magnetite and the dissolution monitored; the high velocity of the jet ensures that mass transfer effects are minimised. The magnetite is synthesised by a solid-state method involving heating a mixture of haematite and iron under vacuum at 600 deg. C, compacting under pressure and sintering into a pellet under argon at 1,100 deg. C. The product has an appropriate consistency and resistance to erosion. Most experiments have measured the average dissolution rate by estimating the amount of magnetite lost from the pellet by surface analysis and profilometry after exposure for a given time. Concomitant electrochemical information is obtained by electrically isolating the pellet from the loop and connecting it to a potentiostat, along with a counter-electrode and reference electrode strategically mounted in the loop test section. Detailed kinetic data are obtained by irradiating the magnetite before installation in the loop and monitoring on-line with gamma spectrometry the transport of dissolved, radioactive 59 Fe. Preliminary determinations had used radioactive magnetite precipitated under galvanostatic conditions from a solution of irradiated FeSO 4 in EDTA onto a platinum coupon. The coupon was then mounted axially in the loop test section and subjected to a range of imposed potentials during exposure; however, this coupon technique gave dissolution results confounded by the release of magnetite crystallites, so we concentrated on the pellet technique. The paper presents the results of exposures carried out over a range of temperatures and alkalinities at oxygen concentrations between 0 and 20 ppb. It shows how dissolution rate constants obtained under CANDU primary coolant conditions of 310 deg. C and pH 25C 10.5 (with LiOH) fall between published values, which were obtained with a different technique under

  9. Growth-promoting effects of a seaweed concentrate at various pH and water hardness conditions

    Directory of Open Access Journals (Sweden)

    Georgina D. Arthur

    2013-11-01

    Full Text Available Kelpak® – a liquid seaweed concentrate made from the kelp Ecklonia maxima (Osbeck Papenfuss – is used as a natural biostimulant to promote rooting and improve yield in crops. Plant–soil environmental conditions and the chemistry of water used for irrigation may affect the efficiency of Kelpak. The effect of pH (pH 4.5, 6.5 and 8.5 and water hardness (200 mg/L and 400 mg/L Ca2+ on the growth-promoting ability of Kelpak was assessed using the mungbean rooting bioassay and in a pot trial with Swiss chard. Kelpak promoted rooting in all the treatments in the mungbean bioassay with maximum rooting generally achieved with 20% Kelpak. With 20% Kelpak, the addition of 200 mg/L and 400 mg/L Ca2+ decreased rooting at pH 4.5, increased rooting at pH 6.5 and did not affect rooting at pH 8.5. A similar trend was observed in the pot trial with Swiss chard: leaf and root (fresh weight and pigment content (chl a, chl b and carotenoids improved with the addition of 200 mg/L Ca2+ + 5% Kelpak at pH 6.5 or pH 8.5, while Kelpak was able to partially mask the negative effect of 200 mg/L Ca2+ at pH 4.5. These results suggest that while Kelpak is most effective in neutral pHs, it can be used to promote plant growth in a wide range of pH and water hardness conditions.

  10. Optimization of pH and direct imaging conditions of complexed ...

    Indian Academy of Sciences (India)

    Unknown

    Materials with light induced absorption or refractive index changes are of ... showed that high pH and high exposure energy gave .... Figure 4. A plot of rate of bleaching vs time for different pH. ... Moreover, it does not need any dark room.

  11. Performance of asphaltic concrete incorporating styrene butadiene rubber subjected to varying aging condition

    Science.gov (United States)

    Salah, Faisal Mohammed; Jaya, Ramadhansyah Putra; Mohamed, Azman; Hassan, Norhidayah Abdul; Rosni, Nurul Najihah Mad; Mohamed, Abdullahi Ali; Agussabti

    2017-12-01

    The influence of styrene butadiene rubber (SBR) on asphaltic concrete properties at different aging conditions was presented in this study. These aging conditions were named as un-aged, short-term, and long-term aging. The conventional asphalt binder of penetration grade 60/70 was used in this work. Four different levels of SBR addition were employed (i.e., 0 %, 1 %, 3 %, and 5 % by binder weight). Asphalt concrete mixes were prepared at selected optimum asphalt content (5 %). The performance was evaluated based on Marshall Stability, resilient modulus, and dynamic creep tests. Results indicated the improving stability and permanent deformation characteristics that the mixes modified with SBR polymer have under aging conditions. The result also showed that the stability, resilient modulus, and dynamic creep tests have the highest rates compared to the short-term aging and un-aged samples. Thus, the use of 5 % SBR can produce more durable asphalt concrete mixtures with better serviceability.

  12. The Metal-Halide Lamp Under Varying Gravity Conditions Measured by Emission and Laser Absorption Spectroscopy

    Science.gov (United States)

    Flikweert, A. J.; Nimalasuriya, T.; Kroesen, G. M. W.; Haverlag, M.; Stoffels, W. W.

    2009-11-01

    Diffusive and convective processes in the metal-halide lamp cause an unwanted axial colour segregation. Convection is induced by gravity. To understand the flow phenomena in the arc discharge lamp it has been investigated under normal laboratory conditions, micro-gravity (ISS and parabolic flights) and hyper-gravity (parabolic flights 2 g, centrifuge 1 g-10 g). The measurement techniques are webcam imaging, and emission and laser absorption spectroscopy. This paper aims to give an overview of the effect of different artificial gravity conditions on the lamp and compares the results from the three measurement techniques.

  13. Pre-Swirl Stator and Propeller Design for Varying Operating Conditions

    DEFF Research Database (Denmark)

    Saettone, Simone; Regener, Pelle Bo; Andersen, Poul

    2016-01-01

    blades ahead of the propeller.This paper describes the hydrodynamic design of apre-swirl stator with radially variable pitch, paired with aconventional propeller. The aim is to achieve the highest possible effciency in various operating conditions, and to avoid effciency penalties in off-design operation.......To investigate the propeller and stator designs and configurations in different operating conditions, the computationally inexpensive vortex-lattice method is used a sa first step to optimize the geometry in an initial parameter study. Then the flow over hull, stator and propelleris simulated in a CFD...

  14. Experimental study on Kd of 137Cs at varying suspended load conditions

    International Nuclear Information System (INIS)

    Jaison, T.J.; Jain, Abhishek; Patra, A.K.; Ravi, P.M.; Tripathi, R.M.

    2018-01-01

    137 Cs is one of the radionuclide likely to be released through liquid effluents from a nuclear facility. It is soluble in water, but its mobility in aquatic environments is highly retarded by its strong interaction with suspended sediment. The 137 Cs + sorption by suspended load, especially in the subtropics and tropics are not fully understood. Besides, according to IAEA document in emergency situation 137 Cs and 131 I being marker radionuclides, are easier to identify and representative of all the other radionuclides present. Hence a laboratory study is carried out on sorption of 137 Cs with varying silt load, using the upstream lake water and sediments to estimate site specific distribution coefficient (K d )

  15. Basic regulatory principles of Escherichia coli's electron transport chain for varying oxygen conditions

    NARCIS (Netherlands)

    Henkel, S.G.; Ter Beek, A.S.; Steinsiek, S.; Stagge, S.; Bettenbrock, K.; Teixeira De Mattos, M.J.; Sauter, T.; Sawodny, O.; Ederer, M.

    2014-01-01

    For adaptation between anaerobic, micro-aerobic and aerobic conditions Escherichia coli's metabolism and in particular its electron transport chain (ETC) is highly regulated. Although it is known that the global transcriptional regulators FNR and ArcA are involved in oxygen response it is unclear

  16. Adult Tea Green Leafhoppers, Empoasca onukii (Matsuda), Change Behaviors under Varying Light Conditions.

    Science.gov (United States)

    Shi, Longqing; Vasseur, Liette; Huang, Huoshui; Zeng, Zhaohua; Hu, Guiping; Liu, Xin; You, Minsheng

    2017-01-01

    Insect behaviors are often influenced by light conditions including photoperiod, light intensity, and wavelength. Understanding pest insect responses to changing light conditions may help with developing alternative strategies for pest control. Little is known about the behavioral responses of leafhoppers (Hemiptera: Cicadellidae) to light conditions. The behavior of the tea green leafhopper, Empoasca onukii Matsuda, was examined when exposed to different light photoperiods or wavelengths. Observations included the frequency of locomotion and cleaning activities, and the duration of time spent searching. The results suggested that under normal photoperiod both female and male adults were generally more active in darkness (i.e., at night) than in light. In continuous darkness (DD), the locomotion and cleaning events in Period 1 (7:00-19:00) were significantly increased, when compared to the leafhoppers under normal photoperiod (LD). Leafhoppers, especially females, changed their behavioral patterns to a two day cycle under DD. Under continuous illumination (continuous quartz lamp light, yellow light at night, and green light at night), the activities of locomotion, cleaning, and searching were significantly suppressed during the night (19:00-7:00) and locomotion activities of both females and males were significantly increased during the day (7:00-19:00), suggesting a shift in circadian rhythm. Our work suggests that changes in light conditions, including photoperiod and wavelength, can influence behavioral activities of leafhoppers, potentially affecting other life history traits such as reproduction and development, and may serve as a method for leafhopper behavioral control.

  17. Fate of As(V)-treated nano zero-valent iron: determination of arsenic desorption potential under varying environmental conditions by phosphate extraction.

    Science.gov (United States)

    Dong, Haoran; Guan, Xiaohong; Lo, Irene M C

    2012-09-01

    Nano zero-valent iron (NZVI) offers a promising approach for arsenic remediation, but the spent NZVI with elevated arsenic content could arouse safety concerns. This study investigated the fate of As(V)-treated NZVI (As-NZVI), by examining the desorption potential of As under varying conditions. The desorption kinetics of As from As-NZVI as induced by phosphate was well described by a biphasic rate model. The effects of As(V)/NZVI mass ratio, pH, and aging time on arsenic desorption from As-NZVI by phosphate were investigated. Less arsenic desorption was observed at lower pH or higher As(V)/NZVI mass ratio, where stronger complexes (bidentate) formed between As(V) and NZVI corrosion products as indicated by FTIR analysis. Compared with the fresh As-NZVI, the amount of phosphate-extractable As significantly decreased in As-NZVI aged for 30 or 60 days. The results of the sequential extraction experiments demonstrated that a larger fraction of As was sorbed in the crystalline phases after aging, making it less susceptible to phosphate displacement. However, at pH 9, a slightly higher proportion of phosphate-extractable As was observed in the 60-day sample than in the 30-day sample. XPS results revealed the transformation of As(V) to more easily desorbed As(III) during aging and a higher As(III)/As(V) ratio in the 60-day sample at pH 9, which might have resulted in the higher desorption. Copyright © 2012 Elsevier Ltd. All rights reserved.

  18. The in vitro fitness cost of antimicrobial resistance in Escherichia coli varies with the growth conditions

    DEFF Research Database (Denmark)

    Petersen, Andreas; Aarestrup, Frank Møller; Olsen, John Elmerdahl

    2009-01-01

    The objective of this study was to investigate the influence of stressful growth conditions on the fitness cost of antimicrobial resistance in Escherichia coli BJ4 caused by chromosomal mutations and plasmid acquisition. The fitness cost of chromosomal streptomycin resistance increased......H and at high-salt concentrations. Strains with an impaired rpoS demonstrated a reduced fitness only during growth in a high-salt concentration. In conclusion, it was demonstrated that bacterial fitness cost in association with antimicrobial resistance generally increases under stressful growth conditions....... However, the growth potential of bacteria with antimicrobial resistances did not increase in a straightforward manner in these in vitro experiments and is therefore probably even more difficult to predict in vivo....

  19. Varying Conditions for Hexanoic Acid Degradation with BioTigerTM

    International Nuclear Information System (INIS)

    Foreman, Koji; Milliken, Charles; Brigmon, Robin

    2016-01-01

    BioTiger TM (BT) is a consortium of 12 bacteria designed for petroleum waste biodegradation. BT is currently being studied and could be considered for bioremediation of the Athabasca oil sands refineries in Canada and elsewhere. The run-off ponds from the petroleum extraction processes, called tailings ponds, are a mixture of polycyclic aromatic hydrocarbons, naphthenic acids, hydrocarbons, toxic chemicals like heavy metals, water, and sand. Due to environmental regulations the oil industry would like to separate and degrade the hazardous chemical species from the tailings ponds while recycling the water. It has been shown that BT at 30 C° is able to completely degrade 10 mM hexanoic acid (HA) co-metabolically with 0.2% yeast extract (w/v) in 48 hours when starting at 0.4 OD 600nm. After establishing this stable degradation capability, variations were tested to explore the wider parameters of BT activity in temperature, pH, intermediate degradation, co-metabolic dependence, and transfer stability. Due to the vast differences in temperature at various points in the refineries, a wide range of temperatures were assessed. The results indicate that BT retains the ability to degrade HA, a model surrogate for tailings pond contaminants, at temperatures ranging from 15°C to 35°C. Hexanamide (HAM) was shown to be an intermediate generated during the degradation of HA in an earlier work and HAM is completely degraded after 48 hours, indicating that HAM is not the final product of HA degradation. Various replacements for yeast extract were attempted. Glucose, a carbon source; casein amino acids, a protein source; additional ammonia, mimicking known media; and additional phosphate with Wolffe's vitamins and minerals all showed no significant degradation of HA compared to control. Decreasing the yeast extract concentration (0.05%) demonstrated limited but significant degradation. Finally, serial inoculations of BT were performed to determine the stability of

  20. Characterization of Transient Plasma Ignition Flame Kernel Growth for Varying Inlet Conditions

    Science.gov (United States)

    2009-12-01

    from Intercity Manufacturing. Without their expertise in precision machining this thesis would not have been possible. Their countless hours spent...somewhere within the combustor due to the time required to produce the required conditions, and will be travelling at near Mach 5 speeds for most...atmospheric pressure. This sudden drop in pressure creates a rarefaction wave that travels forward in the combustor. The blowdown time for a 1 meter long

  1. Detection of respiratory viruses in shelter dogs maintained under varying environmental conditions

    Directory of Open Access Journals (Sweden)

    Francielle Liz Monteiro

    Full Text Available Abstract Three dog shelters in Rio Grande do Sul were investigated for associations between the occurrence of respiratory viruses and shelter environmental conditions. Nasal secretions randomly collected during the cold season were tested via PCR, and this data collection was followed by nucleotide sequencing of the amplicons. In shelter #1 (poor sanitary and nutritional conditions, high animal density and constant contact between dogs, 78% (58/74 of the nasal samples were positive, 35% (26/74 of which were in single infections and 44% (32/74 of which were in coinfections. Shelters #2 and #3 had satisfactory sanitary and nutritional conditions, outdoors exercise areas (#2 and animal clustering by groups (#3. In shelter #2, 9% (3/35 of the samples were positive for Canine parainfluenza virus (CPIV, and 6% (2/35 were positive for Canid herpesvirus 1 (CaHV-1. In shelter #3, 9% (7/77 of the samples were positive for Canine adenovirus type 2 (CAdV-2, and 1% (1/77 were positive for Canine distemper virus (CDV. The amplicon sequences (CPIV and CDV nucleoprotein gene; CAdV-2 E3 gene; CaHV-1 glycoprotein B gene showed 94-100% nucleotide identity with GenBank sequences. Our results demonstrate that CPIV, CAdV-2 and CDV are common in dog shelters and that their frequencies appear to be related with environmental and nutritional conditions. These results indicate the need for control/prevention measures, including vaccination and environmental management, to minimize these infections and improve dog health.

  2. Transient response of a polymer electrolyte membrane fuel cell subjected to time-varying modulating conditions

    Energy Technology Data Exchange (ETDEWEB)

    Noorani, S.; Shamim, T. [Michigan-Dearborn Univ., Dearborn, MI (United States). Dept. of Mechanical Engineering

    2009-07-01

    In order for fuel cells to compete with internal combustion engines, they must have significant advantages in terms of overall efficiency, weight, packaging, safety and cost. A key requirement is its ability to operate under highly transient conditions during start-up, acceleration, and deceleration with stable performance. Therefore, a better understanding of fuel cell dynamic behaviour is needed along with better water management and distributions inside the cell. Therefore, this study investigated the effect of transient conditions on water distribution inside a polymer electrolyte membrane (PEM) cell. A macroscopic single-fuel cell based, one-dimensional, isothermal mathematical model was used to study the effect of modulating cell voltage on the water distribution of anode, cathode, catalyst layers, and membrane. Compared to other existing models, this model did not rely on the non-physical assumption of the uptake curve equilibrium between the pore vapour and ionomer water in the catalyst layers. Instead, the transition between the two phases was modeled as a finite-rate equilibration process. The modulating conditions were simulated by forcing the temporal variations in fuel cell voltage. The results revealed that cell voltage modulations cause a departure in the cell behaviour from its steady behaviour, and the finite-rate equilibration between the catalyst vapour and liquid water can be a factor in determining the cell response. The cell response is also affected by the modulating frequency and amplitude. The peak cell response was observed at low frequencies. Keywords: fuel cell, water transport, dynamic behaviour, numerical simulations. 9 refs., 1 tab., 5 figs.

  3. Oral complementary medicine and alternative practitioner use varies across chronic conditions and attitudes to risk

    Directory of Open Access Journals (Sweden)

    Robert J Adams

    2010-11-01

    Full Text Available Robert J Adams1, Sarah L Appleton1, Antonia Cole2, Tiffany K Gill3, Anne W Taylor3, Catherine L Hill11The Health Observatory, 2Rheumatology Unit, 3Population Research and Outcomes Unit, SA Health, The University of Adelaide Discipline of Medicine, Queen Elizabeth Hospital, Woodville, AustraliaObjectives: To determine whether chronic conditions and patient factors, such as risk perception and decision-making preferences, are associated with complementary medicine and alternative practitioner use in a representative longitudinal population cohort.Participants and setting: Analysis of data from Stage 2 of the North West Adelaide Health Study of 3161 adults who attended a study clinic visit in 2004–2006. The main outcome measures were the medications brought by participants to the study clinic visit, chronic health conditions, attitudes to risk, levels of satisfaction with conventional medicine, and preferred decision-making style.Results: At least one oral complementary medicine was used by 27.9% of participants, and 7.3% were visiting alternative practitioners (naturopath, osteopath. Oral complementary medicine use was significantly associated with arthritis, osteoporosis, and mental health conditions, but not with other chronic conditions. Any pattern of complementary medicine use was generally significantly associated with female gender, age at least 45 years, patient-driven decision-making preferences (odds ratio [OR] 1.38, 95% confidence interval [CI]: 1.08–1.77, and frequent general practitioner visits (>five per year; OR 3.62, 95% CI: 2.13–6.17. Alternative practitioner visitors were younger, with higher levels of education (diploma/trade [OR 1.88, 95% CI: 1.28–2.76], bachelor’s degree [OR 1.77, 95% CI: 1.11–2.82], income > $80,000 (OR 2.28, 95% CI: 1.26–4.11, female gender (OR 3.15, 95% CI: 2.19–4.52, joint pain not diagnosed as arthritis (OR 1.68, 95% CI: 1.17–2.41, moderate to severe depressive symptoms (OR 2.15, 95% CI

  4. Nitrous Oxide Production and Fluxes from Coastal Sediments under Varying Environmental Conditions

    Science.gov (United States)

    Ziebis, W.; Wankel, S. D.; de Beer, D.; Dentinger, J.; Buchwald, C.; Charoenpong, C.

    2014-12-01

    Although coastal zones represent important contributors to the increasing levels of atmospheric nitrous oxide (N2O), it is still unclear which role benthic processes play and whether marine sediments represent sinks or sources for N2O, since interactions among closely associated microbial groups lead to a high degree of variability. In addition, coastal areas are extremely dynamic regions, often exposed to increased nutrient loading and conditions of depleted oxygen. We investigated benthic N2O fluxes and how environmental conditions affect N2O production in different sediments at 2 different geographical locations (German Wadden Sea, a California coastal lagoon). At each location, a total of 32 sediment cores were taken in areas that differed in sediment type, organic content and pore-water nutrient concentrations, as well as in bioturbation activity. Parallel cores were incubated under in-situ conditions, low oxygen and increased nitrate levels for 10 days. Zones of N2O production and consumption were identified in intact cores by N2O microprofiles at the beginning and end of the experiments. In a collaborative effort to determine the dominant sources of N2O, samples were taken throughout the course of the experiments for the determination of the isotopic composition of N2O (as well as nitrate, nitrite and ammonium). Our results indicate that both, nitrate addition and low oxygen conditions in the overlying water, caused an increase of subsurface N2O production in most sediments, with a high variability between different sediment types. N2O production in the sediments was accompanied by N2O consumption, reducing the fluxes to the water column. In general, organic rich sediments showed the strongest response to environmental changes with increased production and efflux of N2O into the overlying water. Bioturbation activity added to the complexity of N2O dynamics by an increase in nitrification-denitrification processes, as well as enhanced pore-water transport

  5. Oral complementary medicine and alternative practitioner use varies across chronic conditions and attitudes to risk.

    Science.gov (United States)

    Adams, Robert J; Appleton, Sarah L; Cole, Antonia; Gill, Tiffany K; Taylor, Anne W; Hill, Catherine L

    2010-11-08

    To determine whether chronic conditions and patient factors, such as risk perception and decision-making preferences, are associated with complementary medicine and alternative practitioner use in a representative longitudinal population cohort. Analysis of data from Stage 2 of the North West Adelaide Health Study of 3161 adults who attended a study clinic visit in 2004-2006. The main outcome measures were the medications brought by participants to the study clinic visit, chronic health conditions, attitudes to risk, levels of satisfaction with conventional medicine, and preferred decision-making style. At least one oral complementary medicine was used by 27.9% of participants, and 7.3% were visiting alternative practitioners (naturopath, osteopath). Oral complementary medicine use was significantly associated with arthritis, osteoporosis, and mental health conditions, but not with other chronic conditions. Any pattern of complementary medicine use was generally significantly associated with female gender, age at least 45 years, patient-driven decision-making preferences (odds ratio [OR] 1.38, 95% confidence interval [CI]: 1.08-1.77), and frequent general practitioner visits (>five per year; OR 3.62, 95% CI: 2.13-6.17). Alternative practitioner visitors were younger, with higher levels of education (diploma/trade [OR 1.88, 95% CI: 1.28-2.76], bachelor's degree [OR 1.77, 95% CI: 1.11-2.82], income >$80,000 (OR 2.28, 95% CI: 1.26-4.11), female gender (OR 3.15, 95% CI: 2.19-4.52), joint pain not diagnosed as arthritis (OR 1.68, 95% CI: 1.17-2.41), moderate to severe depressive symptoms (OR 2.15, 95% CI: 1.04-4.46), and risk-taking behavior (3.26, 1.80-5.92), or low-to-moderate risk aversion (OR 2.08, 95% CI: 1.26-4.11). Although there is widespread use of complementary medicines in the Australian community, there are differing patterns of use between those using oral complementary medicines and those using alternative practitioners.

  6. Aerodynamic performance of a vibrating piezoelectric fan under varied operational conditions

    International Nuclear Information System (INIS)

    Stafford, J; Jeffers, N

    2014-01-01

    This paper experimentally examines the bulk aerodynamic performance of a vibrating fan operating in the first mode of vibration. The influence of operating condition on the local velocity field has also been investigated to understand the flow distribution at the exit region and determine the stalling condition for vibrating fans. Fan motion has been generated and controlled using a piezoelectric ceramic attached to a stainless steel cantilever. The frequency and amplitude at resonance were 109.4 Hz and 12.5 mm, respectively. A test facility has been developed to measure the pressure-flow characteristics of the vibrating fan and simultaneously conduct local velocity field measurements using particle image velocimetry. The results demonstrate the impact of system characteristics on the local velocity field. High momentum regions generated due to the oscillating motion exist with a component direction that is tangent to the blade at maximum displacement. These high velocity zones are significantly affected by increasing impedance while flow reversal is a dominant feature at maximum pressure rise. The findings outlined provide useful information for design of thermal management solutions that may incorporate this air cooling approach.

  7. Buckling of Nonprismatic Column on Varying Elastic Foundation with Arbitrary Boundary Conditions

    Directory of Open Access Journals (Sweden)

    Ahmad A. Ghadban

    2017-01-01

    Full Text Available Buckling of nonprismatic single columns with arbitrary boundary conditions resting on a nonuniform elastic foundation may be considered as the most generalized treatment of the subject. The buckling differential equation for such columns is extremely difficult to solve analytically. Thus, the authors propose a numerical approach by discretizing the column into a finite number of segments. Each segment has constants E (modulus of elasticity, I (moment of inertia, and β (subgrade stiffness. Next, an exact analytical solution is derived for each prismatic segment resting on uniform elastic foundation. These segments are then assembled in a matrix from which the critical buckling load is obtained. The derived formulation accounts for different end boundary conditions. Validation is performed by benchmarking the present results against analytical solutions found in the literature, showing excellent agreement. After validation, more examples are solved to illustrate the power and flexibility of the proposed method. Overall, the proposed method provides reasonable results, and the examples solved demonstrate the versatility of the developed approach and some of its many possible applications.

  8. Schema bias in source monitoring varies with encoding conditions: support for a probability-matching account.

    Science.gov (United States)

    Kuhlmann, Beatrice G; Vaterrodt, Bianca; Bayen, Ute J

    2012-09-01

    Two experiments examined reliance on schematic knowledge in source monitoring. Based on a probability-matching account of source guessing, a schema bias will only emerge if participants do not have a representation of the source-item contingency in the study list, or if the perceived contingency is consistent with schematic expectations. Thus, the account predicts that encoding conditions that affect contingency detection also affect schema bias. In Experiment 1, the schema bias commonly found when schematic information about the sources is not provided before encoding was diminished by an intentional source-memory instruction. In Experiment 2, the depth of processing of schema-consistent and schema-inconsistent source-item pairings was manipulated. Participants consequently overestimated the occurrence of the pairing type they processed in a deep manner, and their source guessing reflected this biased contingency perception. Results support the probability-matching account of source guessing. PsycINFO Database Record (c) 2012 APA, all rights reserved.

  9. Rimsulfuron in Soil: Effects on Microbiological Properties under Varying Soil Conditions

    Directory of Open Access Journals (Sweden)

    Ljiljana Radivojević

    2011-01-01

    Full Text Available The effects of rimsulfuron a sulfonylurea herbicide on the growth and activity of soil microorganisms under laboratory conditions was investigated in two soils. The application rates were: 0.2, 2.0 and 20.0 mg a.i kg-1 soil. The lowest concentration tested was the label rate (0.2 mg a.i kg-1, and the other two were ten and hundred timeshigher. No adverse effects on microbiological processes were observed for the label rate. Decrease in microbial biomass carbon, dehydrogenase activity, fungi and bacteria in comparison with untreated control, were found at higher rates. The magnitude of these effects were generally slight and transitory.

  10. IR radiation characteristics of rocket exhaust plumes under varying motor operating conditions

    Directory of Open Access Journals (Sweden)

    Qinglin NIU

    2017-06-01

    Full Text Available The infrared (IR irradiance signature from rocket motor exhaust plumes is closely related to motor type, propellant composition, burn time, rocket geometry, chamber parameters and flight conditions. In this paper, an infrared signature analysis tool (IRSAT was developed to understand the spectral characteristics of exhaust plumes in detail. Through a finite volume technique, flow field properties were obtained through the solution of axisymmetric Navier-Stokes equations with the Reynolds-averaged approach. A refined 13-species, 30-reaction chemistry scheme was used for combustion effects and a k-ε-Rt turbulence model for entrainment effects. Using flowfield properties as input data, the spectrum was integrated with a line of sight (LOS method based on a single line group (SLG model with Curtis-Godson approximation. The model correctly predicted spectral distribution in the wavelengths of 1.50–5.50 μm and had good agreement for its location with imaging spectrometer data. The IRSAT was then applied to discuss the effects of three operating conditions on IR signatures: (a afterburning; (b chamber pressure from ignition to cutoff; and (c minor changes in the ratio of hydroxyl-terminated polybutadiene (HTPB binder to ammonium perchlorate (AP oxidizer in propellant. Results show that afterburning effects can increase the size and shape of radiance images with enhancement of radiation intensity up to 40%. Also, the total IR irradiance in different bands can be characterized by a non-dimensional chamber pressure trace in which the maximum discrepancy is less than 13% during ignition and engine cutoff. An increase of chamber pressure can lead to more distinct diamonds, whose distance intervals are extended, and the position of the first diamond moving backwards. In addition, an increase in HTPB/AP causes a significant jump in spectral intensity. The incremental rates of radiance intensity integrated in each band are linear with the increase of HTPB

  11. Hydroxyisohexyl 3-cyclohexene carboxaldehyde (lyral) in patch test preparations under varied storage conditions.

    Science.gov (United States)

    Hamann, Dathan; Hamann, Carsten R; Zimerson, Erik; Bruze, Magnus

    2013-01-01

    The common practice of preparing patch tests in advance has recently been called into question by researchers. It has been established that fragrance compounds are volatile and their testing efficacy may be affected by storage conditions and preparation. Allergens in fragrance mix I rapidly decrease in concentration after preapplication to test chambers. This study aimed to investigate the volatility of hydroxyisohexyl 3-cyclohexene carboxaldehyde (HICC) in petrolatum when stored in test chambers and to explore the correlation between vapor pressure and allergen loss in petrolatum during preparation and storage. Standardized HICC in petrolatum was prepared and stored in IQ Chambers and Finn Chambers with covers at 5°C, 25°C, and 35°C, and concentration was analyzed at intervals for up to 9 days using gel permeation chromatography. Changes in HICC concentrations were not statistically significant at 8 hours at 5°C, 25°C, and 35°C. After 9 days, HICC concentrations were found to fall approximately 30% when stored at 35°C, 10% at 25°C, and less than 5% at 5°C. There was no significant difference between IQ and Finn chambers. Hydroxyisohexyl 3-cyclohexene carboxaldehyde concentrations are more stable in petrolatum than many other studied fragrance allergens, but HICC is still at risk for decreasing concentration when exposed to ambient air or heat for prolonged periods.

  12. Vibration Analysis of a Tire in Ground Contact under Varied Conditions

    Directory of Open Access Journals (Sweden)

    Karakus Murat

    2017-03-01

    Full Text Available The effect of three different factors, which are inflation pressure, vertical load and coefficient of friction on the natural frequencies of a tire (175/70 R13 has been studied. A three dimensional tire model is constructed, using four different material properties and parts in the tire. Mechanical properties of the composite parts are evaluated. After investigating the free vibration, contact analysis is carried out. A concrete block and the tire are modelled together, using three different coefficients of friction. Experiments are run under certain conditions to check the accuracy of the numerical model. The natural frequencies are measured to describe free vibration and vibration of the tire contacted by ground, using a damping monitoring method. It is seen, that experimental and numerical results are in good agreement. On the other hand, investigating the impact of three different factors together is quite difficult on the natural frequencies. When some of these factors are assumed to be constant and the variables are taken one by one, it is easier to assess the effects.

  13. Toxicity of pentachlorophenol to aquatic organisms under naturally varying and controlled environmental conditions

    Energy Technology Data Exchange (ETDEWEB)

    Hedtke, S.F.; West, C.W.; Allen, K.N.; Norberg-King, T.J.; Mount, D.I.

    1986-06-01

    The toxicity of pentachlorophenol (PCP) was determined in the laboratory for 11 aquatic species. Tests were conducted seasonally in ambient Mississippi River water and under controlled conditions in Lake Superior water. Fifty-one acute toxicity tests were conducted, with LC50 values ranging from 85 micrograms/L for the white sucker Catastomus commersoni during the summer to greater than 7770 micrograms/L for the isopod Asellus racovitzai during the winter. The effect of PCP on growth and/or reproduction was determined for seven species. The most sensitive chronically exposed organisms were the cladoceran Ceriodaphnia reticulata and the snail Physa gyrina. The greatest variation in toxicity was due to species sensitivity. Within a given, season there was as much as a 40-fold difference in LC50 values between species. For any one species, the maximum variation in LC50 between seasons was approximately 14-fold. There were also substantial differences in acute-chronic relationships, with acute/chronic ratios ranging from greater than 37 for C. reticulata to 1 for Simocephalus vetulus. It is suggested that the composition of the aquatic community should be the most important consideration in estimating the potential environmental effects of PCP.

  14. Comparison of the kinetics of different Markov models for ligand binding under varying conditions

    International Nuclear Information System (INIS)

    Martini, Johannes W. R.; Habeck, Michael

    2015-01-01

    We recently derived a Markov model for macromolecular ligand binding dynamics from few physical assumptions and showed that its stationary distribution is the grand canonical ensemble [J. W. R. Martini, M. Habeck, and M. Schlather, J. Math. Chem. 52, 665 (2014)]. The transition probabilities of the proposed Markov process define a particular Glauber dynamics and have some similarity to the Metropolis-Hastings algorithm. Here, we illustrate that this model is the stochastic analog of (pseudo) rate equations and the corresponding system of differential equations. Moreover, it can be viewed as a limiting case of general stochastic simulations of chemical kinetics. Thus, the model links stochastic and deterministic approaches as well as kinetics and equilibrium described by the grand canonical ensemble. We demonstrate that the family of transition matrices of our model, parameterized by temperature and ligand activity, generates ligand binding kinetics that respond to changes in these parameters in a qualitatively similar way as experimentally observed kinetics. In contrast, neither the Metropolis-Hastings algorithm nor the Glauber heat bath reflects changes in the external conditions correctly. Both converge rapidly to the stationary distribution, which is advantageous when the major interest is in the equilibrium state, but fail to describe the kinetics of ligand binding realistically. To simulate cellular processes that involve the reversible stochastic binding of multiple factors, our pseudo rate equation model should therefore be preferred to the Metropolis-Hastings algorithm and the Glauber heat bath, if the stationary distribution is not of only interest

  15. Comparison of the kinetics of different Markov models for ligand binding under varying conditions

    Energy Technology Data Exchange (ETDEWEB)

    Martini, Johannes W. R., E-mail: jmartin2@gwdg.de [Max Planck Institute for Developmental Biology, Tübingen (Germany); Felix Bernstein Institute for Mathematical Statistics in the Biosciences, University of Göttingen, Göttingen (Germany); Habeck, Michael, E-mail: mhabeck@gwdg.de [Felix Bernstein Institute for Mathematical Statistics in the Biosciences, University of Göttingen, Göttingen (Germany); Max Planck Institute for Biophysical Chemistry, Göttingen (Germany)

    2015-03-07

    We recently derived a Markov model for macromolecular ligand binding dynamics from few physical assumptions and showed that its stationary distribution is the grand canonical ensemble [J. W. R. Martini, M. Habeck, and M. Schlather, J. Math. Chem. 52, 665 (2014)]. The transition probabilities of the proposed Markov process define a particular Glauber dynamics and have some similarity to the Metropolis-Hastings algorithm. Here, we illustrate that this model is the stochastic analog of (pseudo) rate equations and the corresponding system of differential equations. Moreover, it can be viewed as a limiting case of general stochastic simulations of chemical kinetics. Thus, the model links stochastic and deterministic approaches as well as kinetics and equilibrium described by the grand canonical ensemble. We demonstrate that the family of transition matrices of our model, parameterized by temperature and ligand activity, generates ligand binding kinetics that respond to changes in these parameters in a qualitatively similar way as experimentally observed kinetics. In contrast, neither the Metropolis-Hastings algorithm nor the Glauber heat bath reflects changes in the external conditions correctly. Both converge rapidly to the stationary distribution, which is advantageous when the major interest is in the equilibrium state, but fail to describe the kinetics of ligand binding realistically. To simulate cellular processes that involve the reversible stochastic binding of multiple factors, our pseudo rate equation model should therefore be preferred to the Metropolis-Hastings algorithm and the Glauber heat bath, if the stationary distribution is not of only interest.

  16. Modeling Quantum Dot Nanoparticle Fate and Transport in Saturated Porous Media under Varying Flow Conditions

    Science.gov (United States)

    Becker, M. D.; Wang, Y.; Englehart, J.; Pennell, K. D.; Abriola, L. M.

    2010-12-01

    As manufactured nanomaterials become more prevalent in commercial and industrial applications, the development of mathematical models capable of predicting nanomaterial transport and retention in subsurface systems is crucial to assessing their fate and distribution in the environment. A systematic modeling approach based on a modification of clean-bed filtration theory was undertaken to elucidate mechanisms governing the transport and deposition behavior of quantum dots in saturated quartz sand as a function of grain size and flow velocity. The traditional deposition governing equation, which assumes irreversible attachment by a first-order rate (katt), was modified to include a maximum or limiting retention capacity (Smax) and first-order detachment of particles from the solid phase (kdet). Quantum dot mobility experiments were performed in columns packed with three size fractions of Ottawa sand (d50 = 125, 165, and 335 μm) at two different pore-water velocities (0.8 m/d and 7.6 m/d). The CdSe quantum dots in a CdZnS shell and polyacrylic acid coating were negatively charged (zeta potential measured ca. -35 mV) with a hydrodynamic diameter of approximately 30 nm. Fitted values of katt, Smax, and kdet were obtained for each transport and deposition experiment through the implementation of a nonlinear least-squares routine developed to fit the model to experimental breakthrough and retention data via multivariate optimization. Fitted attachment rates and retention capacities increased exponentially with decreasing grain size at both flow rates, while no discernable trend was apparent for the fitted detachment rates. Maximum retention capacity values were plotted against a normalized mass flux expression, which accounts for flow conditions and grain size. A power function fit to the data yielded a dependence that was consistent with a previous study undertaken with fullerene nanoparticles.

  17. Cation effects on phosphatidic acid monolayers at various pH conditions.

    Science.gov (United States)

    Zhang, Ting; Cathcart, Matthew G; Vidalis, Andrew S; Allen, Heather C

    2016-10-01

    The impact of pH and cations on phase behavior, stability, and surface morphology for dipalmitoylphosphatidic acid (DPPA) monolayers was investigated. At pHCations are found to expand and stabilize the monolayer in the following order of increasing magnitude at pH 5.6: Na + >K + ∼Mg 2+ >Ca 2+ . Additionally, cation complexation is tied to the pH and protonation state of DPPA, which are the primary factors controlling the monolayer surface behavior. The binding affinity of cations to the headgroup and thus deprotonation capability of the cation, ranked in the order of Ca 2+ >Mg 2+ >Na + >K + , is found to be well explained by the law of matching water affinities. Nucleation of surface 3D lipid structures is observed from Ca 2+ , Mg 2+ , and Na + , but not from K + , consistent with the lowest binding affinity of K + . Unraveling cation and pH effects on DPPA monolayers is useful in further understanding the surface properties of complex systems such as organic-coated marine aerosols where organic films are directly influenced by the pH and ionic composition of the underlying aqueous phase. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  18. Temperature and pH conditions for mycelial growth of Agaricus brasiliensis on axenic cultivation

    OpenAIRE

    Colauto, Nelson Barros; Universidade Paranaense; Aizono, Patrícia Midori; Universidade Paranaense; Carvalho, Lis Ribeiro Magalhães de; Universidade Paranaense; Paccola-Meirelles, Luzia Doretto; Universidade Estadual de Londrina; Linde, Giani Andrea; Universidade Paranaense

    2008-01-01

    Few studies have been done to determine Agaricus brasiliensis Wasser et al. (A. blazei; A. subrufescens) basic mycelial growth characteristics on axenic cultivation. This study aimed to determine the optimal temperature and initial pH for mycelial growth of A. brasiliensis on malt extract agar medium to develop axenic cultivation techniques. Studied initial pH values for mycelial growth were adjusted to 3.0, 4.0, 5.0, 5.5, with HCl, 6.0, 7.0, 8.0, with NaOH, and again 7.0 and 8.0, with CaCO3....

  19. The solubility and sorption of nickel and niobium under high pH conditions

    International Nuclear Information System (INIS)

    Pilkington, N.J.; Stone, N.S.

    1990-01-01

    The solubilities of nickel and niobium were measured in a range of cement-equilibrated waters. For nickel the effects of cellulose degradation products and of chloride were examined and the dependence of nickel solubility on pH was measured. The sorption of nickel and niobium on to cement representative of the ''near field'' of a radioactive waste repository was also measured. (author)

  20. Nitrogen-Utilization by Plant-Species from Acid Heathland Soils .2. Growth and Shoot/Root Partitioning of No3- Assimilation at Constant Low Ph and Varying No3-/Nh4+ Ratio

    NARCIS (Netherlands)

    Troelstra, S.R.; Wagenaar, R.; Smant, W.

    1995-01-01

    The growth of four heathland species, two grasses (D. flexuosa, M. caerulea) and two dwarf shrubs (C. vulgaris, E. tetralix), was tested in solution culture at pH 4.0 with 2 mol m(-3) N, varying the NO3-/NH4+ ratio up to 40% nitrate. In addition, measurements of NRA, plant chemical composition, and

  1. Influence of coolant pH on corrosion of 6061 aluminum under reactor heat transfer conditions

    International Nuclear Information System (INIS)

    Pawel, S.J.; Felde, D.K.; Pawel, R.E.

    1995-10-01

    To support the design of the Advanced Neutron Source (ANS), an experimental program was conducted wherein aluminum alloy specimens were exposed at high heat fluxes to high-velocity aqueous coolants in a corrosion test loop. The aluminum alloys selected for exposure were candidate fuel cladding materials, and the loop system was constructed to emulate the primary coolant system for the proposed ANS reactor. One major result of this program has been the generation of an experimental database defining oxide film growth on 6061 aluminum alloy cladding. Additionally, a data correlation was developed from the database to permit the prediction of film growth for any reasonable thermal-hydraulic excursion. This capability was utilized effectively during the conceptual design stages of the reactor. During the course of this research, it became clear that the kinetics of film growth on the aluminum alloy specimens were sensitively dependent on the chemistry of the aqueous coolant and that relatively small deviations from the intended pH 5 operational level resulted in unexpectedly large changes in the corrosion behavior. Examination of the kinetic influences and the details of the film morphology suggested that a mechanism involving mass transport from other parts of the test loop was involved. Such a mechanism would also be expected to be active in the operating reactor. This report emphasizes the results of experiments that best illustrate the influence of the nonthermal-hydraulic parameters on film growth and presents data to show that comparatively small variations in pH near 5.0 invoke a sensitive response. Simply, for operation in the temperature and heat flux range appropriate for the ANS studies, coolant pH levels from 4.5 to 4.9 produced significantly less film growth than those from pH 5.1 to 6. A mechanism for this behavior based on the concept of treating the entire loop as an active corrosion system is presented

  2. Electrodialytic extraction of Cr from water-washed MSWI fly ash by changing pH and redox conditions

    DEFF Research Database (Denmark)

    Chen, Wan; Kirkelund, Gunvor Marie; Jensen, Pernille Erland

    2018-01-01

    Electrodialytic process offers a range of possibilities to waste management by electrodialytic separation (EDS) of heavy metals, depending on how the process is designed. Using three EDS cell setups (two two-compartment and one three-compartment) and their combinations, the extraction of Cr from...... rate of 27.5%, is an improvement on the single-step that extracted maximum 3.1%. The highest extraction was obtained due to the combined extraction of Cr(III) under low pH (accompanied with high redox) conditions and Cr(VI) under high pH (low redox) conditions subsequently. The Cr leaching from...... the treated ashes with acidic pH was lower than from those with alkaline pH; after the three-step treatment, Cr leaching was much lower from the coarse fraction (> 50 µm), as compared to the fine (≤ 50 µm) or the unsieved ash. As for the coarse fraction, two/three-step treatment reduced the leaching of Cr...

  3. Improved fluorescent labeling of chitin oligomers: Chitinolytic properties of acidic mammalian chitinase under somatic tissue pH conditions.

    Science.gov (United States)

    Wakita, Satoshi; Kimura, Masahiro; Kato, Naoki; Kashimura, Akinori; Kobayashi, Shunsuke; Kanayama, Naoto; Ohno, Misa; Honda, Shotaro; Sakaguchi, Masayoshi; Sugahara, Yasusato; Bauer, Peter O; Oyama, Fumitaka

    2017-05-15

    Acidic mammalian chitinase (AMCase) has been implicated in various pathophysiological conditions including asthma, allergic inflammation and food processing. AMCase is most active at pH 2.0, and its activity gradually decreases to up to pH 8. Here we analyzed chitin degradation by AMCase in weak acidic to neutral conditions by fluorophore-assisted carbohydrate electrophoresis established originally for oligosaccharides analysis. We found that specific fragments with slower-than-expected mobility as defined by chitin oligosaccharide markers were generated at pH 5.0∼8.0 as by-products of the reaction. We established an improved method for chitin oligosaccharides suppressing this side reaction by pre-acidification of the fluorophore-labeling reaction mixture. Our improved method specifically detects chitin oligosaccharides and warrants quantification of up to 50nmol of the material. Using this strategy, we found that AMCase produced dimer of N-acetyl-d-glucosamine (GlcNAc) at strong acidic to neutral condition. Moreover, we found that AMCase generates (GlcNAc) 2 as well as (GlcNAc) 3 under physiological conditions. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  4. Varying the agglomeration position of particles in a micro-channel using Acoustic Radiation Force beyond the resonance condition.

    Science.gov (United States)

    Dron, Olivier; Aider, Jean-Luc

    2013-09-01

    It is well-known that particles can be focused at mid-height of a micro-channel using Acoustic Radiation Force (ARF) tuned at the resonance frequency (h=λ/2). The resonance condition is a strong limitation to the use of acoustophoresis (particles manipulation using acoustic force) in many applications. In this study we show that it is possible to focus the particles anywhere along the height of a micro-channel just by varying the acoustic frequency, in contradiction with the resonance condition. This result has been thoroughly checked experimentally. The different physical properties as well as wall materials have been changed. The wall materials is finally the only critical parameters. One of the specificity of the micro-channel is the thickness of the carrier and reflector layer. A preliminary analysis of the experimental results suggests that the acoustic focusing beyond the classic resonance condition can be explained in the framework of the multilayered resonator proposed by Hill [1]. Nevertheless, further numerical studies are needed in order to confirm and fully understand how the acoustic pressure node can be moved over the entire height of the micro channel by varying the acoustic frequency. Despite some uncertainties about the origin of the phenomenon, it is robust and can be used for improved acoustic sorting or manipulation of particles or biological cells in confined set-ups. Copyright © 2013 Elsevier B.V. All rights reserved.

  5. Urban tree species show the same hydraulic response to vapor pressure deficit across varying tree size and environmental conditions.

    Directory of Open Access Journals (Sweden)

    Lixin Chen

    Full Text Available The functional convergence of tree transpiration has rarely been tested for tree species growing under urban conditions even though it is of significance to elucidate the relationship between functional convergence and species differences of urban trees for establishing sustainable urban forests in the context of forest water relations.We measured sap flux of four urban tree species including Cedrus deodara, Zelkova schneideriana, Euonymus bungeanus and Metasequoia glyptostroboides in an urban park by using thermal dissipation probes (TDP. The concurrent microclimate conditions and soil moisture content were also measured. Our objectives were to examine 1 the influence of tree species and size on transpiration, and 2 the hydraulic control of urban trees under different environmental conditions over the transpiration in response to VPD as represented by canopy conductance. The results showed that the functional convergence between tree diameter at breast height (DBH and tree canopy transpiration amount (E(c was not reliable to predict stand transpiration and there were species differences within same DBH class. Species differed in transpiration patterns to seasonal weather progression and soil water stress as a result of varied sensitivity to water availability. Species differences were also found in their potential maximum transpiration rate and reaction to light. However, a same theoretical hydraulic relationship between G(c at VPD = 1 kPa (G(cref and the G(c sensitivity to VPD (-dG(c/dlnVPD across studied species as well as under contrasting soil water and R(s conditions in the urban area.We concluded that urban trees show the same hydraulic regulation over response to VPD across varying tree size and environmental conditions and thus tree transpiration could be predicted with appropriate assessment of G(cref.

  6. Urban tree species show the same hydraulic response to vapor pressure deficit across varying tree size and environmental conditions.

    Science.gov (United States)

    Chen, Lixin; Zhang, Zhiqiang; Ewers, Brent E

    2012-01-01

    The functional convergence of tree transpiration has rarely been tested for tree species growing under urban conditions even though it is of significance to elucidate the relationship between functional convergence and species differences of urban trees for establishing sustainable urban forests in the context of forest water relations. We measured sap flux of four urban tree species including Cedrus deodara, Zelkova schneideriana, Euonymus bungeanus and Metasequoia glyptostroboides in an urban park by using thermal dissipation probes (TDP). The concurrent microclimate conditions and soil moisture content were also measured. Our objectives were to examine 1) the influence of tree species and size on transpiration, and 2) the hydraulic control of urban trees under different environmental conditions over the transpiration in response to VPD as represented by canopy conductance. The results showed that the functional convergence between tree diameter at breast height (DBH) and tree canopy transpiration amount (E(c)) was not reliable to predict stand transpiration and there were species differences within same DBH class. Species differed in transpiration patterns to seasonal weather progression and soil water stress as a result of varied sensitivity to water availability. Species differences were also found in their potential maximum transpiration rate and reaction to light. However, a same theoretical hydraulic relationship between G(c) at VPD = 1 kPa (G(cref)) and the G(c) sensitivity to VPD (-dG(c)/dlnVPD) across studied species as well as under contrasting soil water and R(s) conditions in the urban area. We concluded that urban trees show the same hydraulic regulation over response to VPD across varying tree size and environmental conditions and thus tree transpiration could be predicted with appropriate assessment of G(cref).

  7. Comparison of creep behavior under varying load/temperature conditions between Hastelloy XR alloys with different boron content levels

    International Nuclear Information System (INIS)

    Tsuji, Hirokazu; Nakajima, Hajime; Shindo, Masami; Tanabe, Tatsuhiko; Nakasone, Yuji.

    1996-01-01

    In the design of the high-temperature components, it is often required to predict the creep rupture life under the conditions in which the stress and/or temperature may vary by using the data obtained with the constant load and temperature creep rupture tests. Some conventional creep damage rules have been proposed to meet the above-mentioned requirement. Currently only limited data are available on the behavior of Hastelloy XR, which is a developed alloy as the structural material for high-temperature components of the High-Temperature Engineering Test Reactor (HTTR), under varying stress and/or temperature creep conditions. Hence a series of constant load and temperature creep rupture tests as well as varying load and temperature creep rupture tests was carried out on two kinds of Hastelloy XR alloys whose boron content levels are different, i.e., below 10 and 60 mass ppm. The life fraction rule completely fails in the prediction of the creep rupture life of Hastelloy XR with 60 mass ppm boron under varying load and temperature conditions though the rule shows good applicability for Hastelloy XR with below 10 mass ppm boron. The change of boron content level of the material during the tests is the most probable source of impairing the applicability of the life fraction rule to Hastelloy XR whose boron content level is 60 mass ppm. The modified life fraction rule has been proposed based on the dependence of the creep rupture strength on the boron content level of the alloy. The modified rule successfully predicts the creep rupture life under the two stage creep test conditions from 1000 to 900degC. The trend observed in the two stage creep tests from 900 to 1000degC can be qualitatively explained by the mechanism that the oxide film which is formed during the prior exposure to 900degC plays the role of the protective barrier against the boron dissipation into the environment. (J.P.N.)

  8. Struvite recovery from swine waste biogas digester effluent through a stainless steel device under constant pH conditions.

    Science.gov (United States)

    Perera, P W Anton; Wu, Wei-Xiang; Chen, Ying-Xu; Han, Zhi-Ying

    2009-06-01

    To investigate the struvite precipitation under constant and non-constant pH conditions and to test a stainless steel device under different operating regimes to maximize the recovery of struvite. The molar ratio of NH4+: Mg2+: PO4(3-) was adjusted to 1: 1.2: 1.2 and pH was elevated to 9.0. The absorbance measurement was used to trace the process of struvite crystallization. Wastewater and precipitate analysis was done by standard analytical methods. The pH constant experiment reported a significantly higher struvite precipitation (24.6 +/- 0.86 g) than the non-constant pH experiment (19.8 +/- 1.86 g). The SAR ranged from 5.6 to 8.2 g m(-2) h(-1) to 3.6-4.8 g m(-2) h(-1) in pH constant and non-constant experiments, respectively. The highest struvite deposit on the device was found in regime 3 followed by in regimes 2 and 4. The highest PO4(3-) (97.2%) and NH4+ (71%) removal was reported in the R1 regime. None of the influent Cu2+ or Zn2+ was precipitated on the device. A higher struvite yield is evident in pH constant experiments. Moreover, the stainless steel device facilitates the isolation of heavy metal free pure (around 96%) struvite from swine waste biogas digester effluent contaminated with cu2+ and Zn2+ and the highest yield is attainable with the device operating at 50 rpm with agitation by a magnetic stirrer.

  9. Structural match of heterogeneously nucleated Mn(OH)_2(s) nanoparticles on quartz under various pH conditions

    International Nuclear Information System (INIS)

    Jung, Haesung; Lee, Byeongdu; Jun, Young-Shin

    2016-01-01

    The early nucleation stage of Mn (hydr)oxide on mineral surfaces is crucial to understand its occurrence and the cycling of nutrients in environmental systems. However, there are only limited studies on the heterogeneous nucleation of Mn(OH)_2(s) as the initial stage of Mn (hydr)oxide precipitation. Here, we investigated the effect of pH on the initial nucleation of Mn(OH)_2(s) on quartz. Under various pH conditions of 9.8, 9.9, and 10.1, we analyzed the structural matches between quartz and heterogeneously nucleated Mn(OH)_2(s). The structural matches were calculated by measuring lateral and vertical dimensions using grazing incidence small angle X-ray scattering (GISAXS) and atomic force microscopy (AFM), respectively. We found that a poorer structural match occurred at a higher pH than at a lower pH. The faster nucleation at a higher pH condition accounted for the observed poorer structural match. By fitting the structural match using classical nucleation theory, we also calculated the interfacial energy between Mn(OH)_2(s) and water (γ_n_f = 71 ± 7 mJ/m"2). The calculated m values and γ_n_f provided the variance of interfacial energy between quartz and Mn(OH)_2(s): γ_s_n = 262–272 mJ/m"2. As a result, this study provides new qualitative and quantitative information about heterogeneous nucleation on environmentally an abundant mineral surface, quartz, and it offers important underpinnings for understanding the fate and transport of trace ions in environmental systems.

  10. Fate of cadmium at the soil-solution interface: a thermodynamic study as influenced by varying pH at South 24 Parganas, West Bengal, India.

    Science.gov (United States)

    Karak, Tanmoy; Paul, Ranjit Kumar; Das, Sampa; Das, Dilip K; Dutta, Amrit Kumar; Boruah, Romesh K

    2015-11-01

    A study on the sorption kinetics of Cd from soil solution to soils was conducted to assess the persistence of Cd in soil solution as it is related to the leaching, bioavailability, and potential toxicity of Cd. The kinetics of Cd sorption on two non-contaminated alkaline soils from Canning (22° 18' 48.02″ N and 88° 39' 29.0″ E) and Lakshmikantapur (22° 06' 16.61″ N and 88° 19' 08.66″ E) of South 24 Parganas, West Bengal, India, were studied using conventional batch experiment. The variable soil suspension parameters were pH (4.00, 6.00, 8.18, and 9.00), temperatures (308, 318, and 328 K) and Cd concentrations (5-100 mg L(-1)). The average rate coefficient (kavg) and half-life (t1/2) values indicate that the persistence of Cd in soil solution is influenced by both temperature and soil suspension pH. The concentration of Cd in soil solution decreases with increase of temperature; therefore, Cd sorption on the soil-solution interface is an endothermic one. Higher pH decreases the t 1/2 of Cd in soil solution, indicating that higher pH (alkaline) is not a serious concern in Cd toxicity than lower pH (acidic). Based on the energy of activation (Ea) values, Cd sorption in acidic pH (14.76±0.29 to 64.45±4.50 kJ mol(-1)) is a surface control phenomenon and in alkaline pH (9.33±0.09 to 44.60±2.01 kJ mol(-1)) is a diffusion control phenomenon The enthalpy of activation (ΔH∓) values were found to be between 7.28 and 61.73 kJ mol(-1). Additionally, higher positive energy of activation (ΔG∓) values (46.82±2.01 to 94.47±2.36 kJ mol(-1)) suggested that there is an energy barrier for product formation.

  11. Spore germination and gametophyte development of Cyathea atrovirens (Langsd. & Fisch. Domin (Cyatheaceae under different pH conditions

    Directory of Open Access Journals (Sweden)

    C. Rechenmacher

    Full Text Available Cyathea atrovirens (Langsd. & Fisch. Domin, an intensely exploited tree fern, is found inside forests in several succession stages, as well as in swamps, roadsides and unused fields in the Rio dos Sinos basin, in the state of Rio Grande do Sul, southern Brazil. This study evaluated the in vitro germination and gametophyte development of C.atrovirens under different pH conditions, as well as spore viability after different storage times at 7 ºC. The lowest germination rate of spores was obtained at pH 7.0. At pH 5.0 to 6.5, laminar gametophyte development started at 20 to 30 days of culture. Antheridia and archegonia were first observed at 35 and 128 days, respectively. Storage at 7 ºC did not affect germination rates. The capability of germination at different pH levels may explain the occurrence of the species in a wide range of habitats. The present study contributes to the understanding of the full life-cycle of C. atrovirens and to the analysis of the influence of abiotic components, providing information for the cultivation, management and conservation of the species.

  12. Data showing chemical compositions of the essential oils of the leaves of Cymbopogon citratus obtained by varying pH of the extraction medium

    Directory of Open Access Journals (Sweden)

    E.O. Ajayi

    2016-09-01

    Full Text Available This article describes the various chemical components as obtained from the oils in the leaves of Cymbopogon citratus using hydrodistillation and solvent-free microwave extraction methods. Furthermore, extractions of the oils were also carried out with a slight in pH variation and compared, “GC–MS evaluation of C. citratus (DC Stapf oil obtained using modified hydrodistillation and microwave extraction methods” (Ajayi et al., 2016 [1]. The current article contains one table exhibiting a list of compounds in the four different methods of extraction. Comparative studies amongst the various methods of extraction are highlighted in the table. Keywords: Essential oil, Cymbopogon citratus, pH Extraction medium

  13. Rare Earth Element Behavior During Incongruent Weathering and Varying Discharge Conditions in Silicate Dominated River Systems: The Australian Victorian Alps

    Science.gov (United States)

    Hagedorn, K. B.; Cartwright, I.

    2008-12-01

    The distribution of rare earth elements (REE) and trace elements was measured by ICP-MS on fresh, slightly weathered and weathered granite and surface water samples from a network of 11 pristine rivers draining the Australian Victorian Alps during (i) high and (ii) low discharge conditions. River water REE concentrations are largely derived from atmospheric precipitation (rain, snow), as indicated by similar Chondrite normalized REE patterns (higher LREE over HREE; negative Ce anomalies, positive Eu anomalies) and similar total REE concentrations during both dry and wet seasons. Calculations based on the covariance between REE and Cl concentrations and oxygen and hydrogen isotopes indicate precipitation input coupled with subsequent evaporation may account for 30% o 100% of dissolved REE in stream waters. The dissolved contribution to the granitic substratum to stream water comes mainly from the transformation of plagioclase to smectite, kaolinite and gibbsite and minor apatite dissolution. However, since most REE of the regional granite are present in accessory minerals (titanite, zircon, etc.) they do not significantly contribute to the river REE pool. REE concentrations drop sharply downstream as a result of dilution and chemical attenuation. A trend of downstream enrichment of the heavier REE is due to selective partitioning of the lighter REE (as both free REE or REECO3 complexes) to hydrous oxides of suspended Al which, in turn, is controlled by a downstream increase of pH to values > 6.1 (for free REE) and > 7.3 (for REECO3 complexes). Although most circumneutral waters were supersaturated with REE phosphate compounds, precipitation of LnPO4 is not believed to have been a dominant process because the predicted phosphate fractionation pattern is inconsistent with the observed trends. Negative saturation indices of hydrous ferric oxides also militate against surface complexation onto goethite. Instead, REE attenuation most likely resulted from adsorption onto

  14. Assessing and monitoring the effects of filter material amendments on the biophysicochemical properties during composting of solid winery waste under open field and varying climatic conditions.

    Science.gov (United States)

    Mtimkulu, Y; Meyer, A H; Mulidzi, A R; Shange, P L; Nchu, F

    2017-01-01

    Waste management in winery and distillery industries faces numerous disposal challenges as large volumes of both liquid and solid waste by-products are generated yearly during cellar practices. Composting has been suggested as a feasible option to beneficiate solid organic waste. This incentivized the quest for efficient composting protocols to be put in place. The objective of this study was to experiment with different composting strategies for spent winery solid waste. Compost materials consisting of chopped pruning grape stalks, skins, seed and spent wine filter material consisting of a mixture of organic and inorganic expend ingredients were mixed in compost heaps. The filter material component varied (in percentage) among five treatments: T1 (40%) lined, T2 (20%) lined, T3 (0%) lined, T4 (40%) ground material, lined and T5 (40%) unlined. Composting was allowed to proceed under open field conditions over 12months, from autumn to summer. Indicators such as temperature, moisture, enzyme activities, microbial counts, pH, and C/N ratio, were recorded. Generally, season (df=3, 16, Pwinery solid waste. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Varying hydric conditions during incubation influence egg water exchange and hatchling phenotype in the red-eared slider turtle.

    Science.gov (United States)

    Delmas, Virginie; Bonnet, Xavier; Girondot, Marc; Prévot-Julliard, Anne-Caroline

    2008-01-01

    Environmental conditions within the nest, notably temperature and moisture of substrate, exert a powerful influence during embryogenesis in oviparous reptiles. The influence of fluctuating nest temperatures has been experimentally examined in different reptile species; however, similar experiments using moisture as the key variable are lacking. In this article, we examine the effect of various substrate moisture regimes during incubation on different traits (egg mass, incubation length, and hatchling mass) in a chelonian species with flexible-shelled eggs, the red-eared slider turtle (Trachemys scripta elegans). Our results show that the rate of water uptake by the eggs was higher in wet than in dry substrate and varied across development. More important, during the first third of development, the egg mass changes were relatively independent of the soil moisture level; they became very sensitive to moisture levels during the other two-thirds. Moreover, hydric conditions exerted a strong influence on the eggs' long-term sensitivity to the moisture of the substrate. Even short-term episodes of high or low levels of moisture modified permanently their water sensitivity, notably through modification of eggshell shape and volume, and in turn entailed significant effects on hatchling mass (and hence offspring quality). Such complex influences of fluctuating moisture levels at various incubation stages on hatchling phenotype better reflect the natural situation, compared to experiments based on stable, albeit different, moisture levels.

  16. Stabilization Mechanism of Roxithromycin Tablets under Gastric pH Conditions.

    Science.gov (United States)

    Inukai, Koki; Noguchi, Shuji; Kimura, Shin-Ichiro; Itai, Shigeru; Iwao, Yasunori

    2018-05-31

    Macrolide antibiotics are widely used at clinical sites. Clarithromycin (CAM), a 14-membered macrolide antibiotic, was reported to gelate under acidic conditions. Gelation allows oral administration of acid-sensitive CAM without enteric coating by hindering the penetration of gastric fluid into CAM tablets. However, it is unknown whether this phenomenon occurs in other macrolide antibiotics. In this study, we examined the gelation ability of three widely used macrolide antibiotics, roxithromycin (RXM), erythromycin A (EM), and azithromycin (AZM). The results indicated that not only CAM but also RXM gelated under acidic conditions. EM and AZM did not gelate under the same conditions. Gelation of RXM delayed the disintegration of the tablet and release of RXM from the tablet. Disintegration and release were also delayed in commercial RXM tablets containing disintegrants. This study showed that two of the four macrolides gelated, which affects tablet disintegration and dissolution and suggests that this phenomenon might also occur in other macrolides. Copyright © 2018. Published by Elsevier Inc.

  17. Roles of iron species and pH optimization on sewage sludge conditioning with Fenton's reagent and lime.

    Science.gov (United States)

    Yu, Wenbo; Yang, Jiakuan; Shi, Yafei; Song, Jian; Shi, Yao; Xiao, Jun; Li, Chao; Xu, Xinyu; He, Shu; Liang, Sha; Wu, Xu; Hu, Jingping

    2016-05-15

    Conditioning sewage sludge with Fenton's reagent could effectively improve its dewaterability. However, drawbacks of conditioning with Fenton's reagent are requirement of acidic conditions to prevent iron precipitation and subsequent neutralization with alkaline additive to obtain the pH of the filtrate close to neutrality. In this study, roles of pH were thoroughly investigated in the acidification pretreatment, Fenton reaction, and the final filtrate after conditioning. Through the response surface methodology (RSM), the optimal dosages of H2SO4, Fe(2+), H2O2, and lime acted as a neutralizer were found to be 0 (no acidification), 47.9, 34.3 and 43.2 mg/g DS (dry solids). With those optimal doses, water content of the dewatered sludge cakes could be reduced to 55.8 ± 0.6 wt%, and pH of the final filtrate was 6.6 ± 0.2. Fenton conditioning without initial acidification can simplify the conditioning process and reduce the usage of lime. The Fe(3+) content in the sludge cakes showed a close correlation with the dewaterability of conditioned sludge, i.e., the water content of sludge cakes, SRF (specific resistance to filtration), CST (capillary suction time), bound water content, and specific surface area. It indicated that the coagulation by Fe(3+) species in Fenton reaction could play an important role, compared to traditional Fenton oxidation effect on sludge conditioning. Thus, a two-step mechanism of Fenton oxidation and Fe(III) coagulation was proposed in sewage sludge conditioning. The mechanisms include the following: (1) extracellular polymeric substances (EPS) were firstly degraded into dissolved organics by Fenton oxidation; (2) bound water was converted to free water due to degradation of EPS; (3) the sludge particles were disintegrated into small ones by oxidation; (4) Fe(3+) generated from Fenton reaction acted as a coagulant to agglomerate smaller sludge particles into larger dense particles with less bond water; (5) finally, the dewatered

  18. Experiments and numerical modeling of fast flowing liquid metal thin films under spatially varying magnetic field conditions

    Science.gov (United States)

    Narula, Manmeet Singh

    Innovative concepts using fast flowing thin films of liquid metals (like lithium) have been proposed for the protection of the divertor surface in magnetic fusion devices. However, concerns exist about the possibility of establishing the required flow of liquid metal thin films because of the presence of strong magnetic fields which can cause flow disrupting MHD effects. A plan is underway to design liquid lithium based divertor protection concepts for NSTX, a small spherical torus experiment at Princeton. Of these, a promising concept is the use of modularized fast flowing liquid lithium film zones, as the divertor (called the NSTX liquid surface module concept or NSTX LSM). The dynamic response of the liquid metal film flow in a spatially varying magnetic field configuration is still unknown and it is suspected that some unpredicted effects might be lurking. The primary goal of the research work being reported in this dissertation is to provide qualitative and quantitative information on the liquid metal film flow dynamics under spatially varying magnetic field conditions, typical of the divertor region of a magnetic fusion device. The liquid metal film flow dynamics have been studied through a synergic experimental and numerical modeling effort. The Magneto Thermofluid Omnibus Research (MTOR) facility at UCLA has been used to design several experiments to study the MHD interaction of liquid gallium films under a scaled NSTX outboard divertor magnetic field environment. A 3D multi-material, free surface MHD modeling capability is under development in collaboration with HyPerComp Inc., an SBIR vendor. This numerical code called HIMAG provides a unique capability to model the equations of incompressible MHD with a free surface. Some parts of this modeling capability have been developed in this research work, in the form of subroutines for HIMAG. Extensive code debugging and benchmarking exercise has also been carried out. Finally, HIMAG has been used to study the

  19. Metal release from contaminated coastal sediments under changing pH conditions: Implications for metal mobilization in acidified oceans.

    Science.gov (United States)

    Wang, Zaosheng; Wang, Yushao; Zhao, Peihong; Chen, Liuqin; Yan, Changzhou; Yan, Yijun; Chi, Qiaoqiao

    2015-12-30

    To investigate the impacts and processes of CO2-induced acidification on metal mobilization, laboratory-scale experiments were performed, simulating the scenarios where carbon dioxide was injected into sediment-seawater layers inside non-pressurized chambers. Coastal sediments were sampled from two sites with different contamination levels and subjected to pre-determined pH conditions. Sediment samples and overlying water were collected for metal analysis after 10-days. The results indicated that CO2-induced ocean acidification would provoke increased metal mobilization causing adverse side-effects on water quality. The mobility of metals from sediment to the overlying seawater was correlated with the reduction in pH. Results of sequential extractions of sediments illustrated that exchangeable metal forms were the dominant source of mobile metals. Collectively, our data revealed that high metal concentrations in overlying seawater released from contaminated sediments under acidic conditions may strengthen the existing contamination gradients in Maluan Bay and represent a potential risk to ecosystem health in coastal environments. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Modeling of acetate-type fermentation of sugar-containing wastewater under acidic pH conditions.

    Science.gov (United States)

    Huang, Liang; Pan, Xin-Rong; Wang, Ya-Zhou; Li, Chen-Xuan; Chen, Chang-Bin; Zhao, Quan-Bao; Mu, Yang; Yu, Han-Qing; Li, Wen-Wei

    2018-01-01

    In this study, a kinetic model was developed based on Anaerobic Digestion Model No. 1 to provide insights into the directed production of acetate and methane from sugar-containing wastewater under low pH conditions. The model sufficiently described the dynamics of liquid-phase and gaseous products in an anaerobic membrane bioreactor by comprehensively considering the syntrophic bioconversion steps of sucrose hydrolysis, acidogenesis, acetogenesis and methanogenesis under acidic pH conditions. The modeling results revealed a significant pH-dependency of hydrogenotrophic methanogenesis and ethanol-producing processes that govern the sucrose fermentative pathway through changing the hydrogen yield. The reaction thermodynamics of such acetate-type fermentation were evaluated, and the implications for process optimization by adjusting the hydraulic retention time were discussed. This work sheds light on the acid-stimulated acetate-type fermentation process and may lay a foundation for optimization of resource-oriented processes for treatment of food wastewater. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Impact of Varying Wave Conditions on the Mobility of Arsenic in a Nearshore Aquifer on the Great Lakes

    Science.gov (United States)

    Rakhimbekova, S.; O'Carroll, D. M.; Robinson, C. E.

    2017-12-01

    Groundwater-coastal water interactions play an important role in controlling the behavior of inorganic chemicals in nearshore aquifers and the subsequent flux of these chemicals to receiving coastal waters. Previous studies have shown that dynamic groundwater flows and water exchange across the sediment-water interface can set up strong geochemical gradients and an important reaction zone in a nearshore aquifer that affect the fate of reactive chemicals. There is limited understanding of the impact of transient coastal forcing such as wave conditions on groundwater dynamics and geochemistry in a nearshore aquifer. The goal of this study was to assess the impact of intensified wave conditions on the behavior of arsenic in a nearshore aquifer and to determine the hydrological and geochemical factors controlling its fate and ultimate delivery to receiving coastal waters. Field investigations were conducted over the period of intensified wave conditions on a freshwater beach on Lake Erie, Canada. High spatial resolution aqueous and sediment sampling was conducted to characterize the subsurface distribution of inorganic species in the nearshore aquifer. Numerical groundwater flow and transport simulations were conducted to evaluate wave-induced perturbations in the flow dynamics including characterizing changes in the groundwater flow recirculations in the nearshore aquifer. The combination of field data and numerical simulations reveal that varying wave conditions alter groundwater flows and set up geochemical transition zones within the aquifer resulting in the release and sequestration of arsenic. Interactions between oxic surface water, mildly reducing shallow groundwater, and reducing sulfur- and iron-rich deep groundwater promote dynamic iron, sulfur and manganese cycling which control the mobility of arsenic in the aquifer. The findings of this study have potential implications for the fate and transport of other reactive chemicals (e.g. phosphorus, mercury) in

  2. Physico-chemical changes of ZnO nanoparticles with different size and surface chemistry under physiological pH conditions.

    Science.gov (United States)

    Gwak, Gyeong-Hyeon; Lee, Won-Jae; Paek, Seung-Min; Oh, Jae-Min

    2015-03-01

    We studied the physico-chemical properties of ZnO nanoparticles under physiological pH conditions (gastric, intestinal and plasma) as functions of their size (20 and 70 nm) and surface chemistry (pristine, L-serine, or citrate coating). ZnO nanoparticles were dispersed in phosphate buffered saline under physiological pH conditions and aliquots were collected at specific time points (0.5, 1, 4, 10 and 24 h) for further characterization. The pH values of the aqueous ZnO colloids at each condition were in the neutral to slightly basic range and showed different patterns depending on the original size and surface chemistry of the ZnO nanoparticles. The gastric pH condition was found to significantly dissolve ZnO nanoparticles up to 18-30 wt%, while the intestinal or plasma pH conditions resulted in much lower dissolution amounts than expected. Based on the X-ray diffraction patterns and X-ray absorption spectra, we identified partial phase transition of the ZnO nanoparticles from wurtzite to Zn(OH)2 under the intestinal and plasma pH conditions. Using scanning electron microscopy, we verified that the overall particle size and morphology of all ZnO nanoparticles were maintained regardless of the pH. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Evaluation of the Survivability of Microorganisms Deposited on Filtering Respiratory Protective Devices under Varying Conditions of Humidity

    Directory of Open Access Journals (Sweden)

    Katarzyna Majchrzycka

    2016-01-01

    Full Text Available Bioaerosols are common biological factors in work environments, which require routine use of filtering respiratory protective devices (FRPDs. Currently, no studies link humidity changes in the filter materials of such devices, during use, with microorganism survivability. Our aim was to determine the microclimate inside FRPDs, by simulating breathing, and to evaluate microorganism survivability under varying humidity conditions. Breathing was simulated using commercial filtering facepiece respirators in a model system. Polypropylene melt-blown nonwoven fabrics with moisture contents of 40%, 80%, and 200%, were used for assessment of microorganisms survivability. A modified AATCC 100-2004 method was used to measure the survivability of ATCC and NCAIM microorganisms: Escherichia coli, Staphylococcus aureus, Bacillus subtilis, Candida albicans and Aspergillus niger. During simulation relative humidity under the facepiece increased after 7 min of usage to 84%–92% and temperature increased to 29–30 °C. S. aureus survived the best on filter materials with 40%–200% moisture content. A decrease in survivability was observed for E. coli and C. albicans when mass humidity decreased. We found that B. subtilis and A. niger proliferated for 48–72 h of incubation and then died regardless of the moisture content. In conclusion, our tests showed that the survivability of microorganisms on filter materials depends on the amount of accumulated moisture and microorganism type.

  4. Evaluation of the Survivability of Microorganisms Deposited on Filtering Respiratory Protective Devices under Varying Conditions of Humidity.

    Science.gov (United States)

    Majchrzycka, Katarzyna; Okrasa, Małgorzata; Skóra, Justyna; Gutarowska, Beata

    2016-01-04

    Bioaerosols are common biological factors in work environments, which require routine use of filtering respiratory protective devices (FRPDs). Currently, no studies link humidity changes in the filter materials of such devices, during use, with microorganism survivability. Our aim was to determine the microclimate inside FRPDs, by simulating breathing, and to evaluate microorganism survivability under varying humidity conditions. Breathing was simulated using commercial filtering facepiece respirators in a model system. Polypropylene melt-blown nonwoven fabrics with moisture contents of 40%, 80%, and 200%, were used for assessment of microorganisms survivability. A modified AATCC 100-2004 method was used to measure the survivability of ATCC and NCAIM microorganisms: Escherichia coli, Staphylococcus aureus, Bacillus subtilis, Candida albicans and Aspergillus niger. During simulation relative humidity under the facepiece increased after 7 min of usage to 84%-92% and temperature increased to 29-30 °C. S. aureus survived the best on filter materials with 40%-200% moisture content. A decrease in survivability was observed for E. coli and C. albicans when mass humidity decreased. We found that B. subtilis and A. niger proliferated for 48-72 h of incubation and then died regardless of the moisture content. In conclusion, our tests showed that the survivability of microorganisms on filter materials depends on the amount of accumulated moisture and microorganism type.

  5. The effects of intermittent exposure to low pH and oxygen conditions on survival and growth of juvenile red abalone

    Science.gov (United States)

    Kim, T. W.; Barry, J. P.; Micheli, F.

    2013-02-01

    Exposure of nearshore animals to hypoxic, low pH waters upwelled from below the continental shelf and advected near the coast may be stressful to marine organisms and lead to impaired physiological performance. We mimicked upwelling conditions in the laboratory and tested the effect of fluctuating exposure to water with low pH and/or low oxygen levels on the mortality and growth of juvenile red abalone (Haliotis rufescens, shell length 5-10 mm). Mortality rates of juvenile abalone exposed to low pH (7.5, total scale) and low O2 (40% saturation, 5 mg L-1) conditions for periods of 3 to 6 h every 3-5 days over 2 weeks did not differ from those exposed to control conditions (O2: 100% saturation, 12 mg L-1; pH 8.0). However, when exposure was extended to 24 h repeated twice over a 15 day period, juveniles experienced higher mortality in the low oxygen treatments compared to control conditions, regardless of pH levels (pH 7.5 vs. 8.0). Growth rates were reduced significantly when juveniles were exposed to low pH or low oxygen treatments and the growth was lowest when low pH exposure was combined with low O2. Furthermore, individual variation of growth rate increased when they were exposed to low pH and low O2 conditions. These results indicate that prolonged exposure to low oxygen levels is detrimental for the survival of red abalone, whereas both pH and oxygen is a crucial factor for their growth. However, given the higher individual variation in growth rate, they may have an ability to adapt to extended exposure to upwelling conditions.

  6. Relationship between continuity of care and adverse outcomes varies by number of chronic conditions among older adults with diabetes

    Directory of Open Access Journals (Sweden)

    Eva H. DuGoff

    2016-06-01

    Full Text Available Follow us on Twitter Co-Editors-in-Chief Martin Fortin Jane Gunn Stewart W. Mercer Susan Smith Marjan van den Akker Society for Academic Primary Care Journal Help USER You are logged in as... avalster My Profile Log Out JOURNAL CONTENT Search Search Scope Search Browse By Issue By Author By Title By Sections By Identify Types OPEN JOURNAL SYSTEMS FONT SIZE Make font size smallerMake font size defaultMake font size larger INFORMATION For Readers For Authors For Librarians ARTICLE TOOLS Print this article Indexing metadata How to cite item Supplementary files Finding References Email this article Email the author Post a Comment NOTIFICATIONS View (378 new Manage IRCMO NEWS ‘Addressing the global challenge of... Publications on multimorbidity... The CARE Plus study Prevalence of multimorbidity in the... Multimorbidity in adults from a... CURRENT ISSUE Atom logo RSS2 logo RSS1 logo HOSTED BY Part of the PKP Publishing Services Network HOME ABOUT USER HOME SEARCH CURRENT ARCHIVES ANNOUNCEMENTS PUBLISHER AUTHOR GUIDELINES SUBMISSIONS WHY PUBLISH WITH US? Home > Vol 6, No 2 (2016 >\tDuGoff Relationship between continuity of care and adverse outcomes varies by number of chronic conditions among older adults with diabetes Eva H. DuGoff, Karen Bandeen-Roche, Gerard F. Anderson Abstract Background: Continuity of care is a basic tenant of primary care practice. However, the evidence on the importance of continuity of care for older adults with complex conditions is mixed. Objective: To assess the relationship between measurement of continuity of care, number of chronic conditions, and health outcomes. Design: We analyzed data from a cohort of 1,600 US older adults with diabetes and ≥1 other chronic condition in a private Medicare health plan from July 2010 to December 2011. Multivariate regression models were used to examine the association of baseline continuity (the first 6 months and the composite outcome of any emergency room use or inpatient

  7. Effects of solution pH and complexing reagents on uranium and thorium desorption under saturated equilibrium conditions

    International Nuclear Information System (INIS)

    Wang, Yug-Yea; Yu, C.

    1992-01-01

    Three contaminated bulk surface soils were used for investigating the effect of solution pH and complexing reagents on uranium and thorium desorption. At a low solution pH, the major chemical species of uranium and thorium, uranyl UO 2 +2 , thorium dihydroxide Th(OH) 2 +2 , and thorium hydroxide Th(OH) +3 , tend to form complexes with acetates in the solution phase, which increases the fractions of uranium and thorium desorbed into this phase. At a high solution pH, important uranium and thorium species such as uranyl tricarbonate complex UO 2 (CO) 33 -4 and thorium tetrahydroxide complex Th(OH) 4 tend to resist complexation with acetates. The presence of complexing reagents in solution can release radionuclides such as uranium and/or thorium from the soil to the solution by forming soluble complexes. Sodium bicarbonate (NaHCO 3 ) and diethylenetriaminepentaacetic acid (DTPA) are strong complex formers that released 38% to 62% of total uranium activity and 78% to 86% of total thorium activity, respectively, from the soil samples investigated. Solutions of 0.1 molar sodium nitrate (NaNO 3 ) and 0.1 molar sodium sulfate (Na 2 SO 4 ) were not effective complex formers with uranium and thorium under the experimental conditions. Fractions of uranium and thorium desorbed by 0.15g/200ml humic acid ranged from 4.62% to 6.17% and 1.59% to 7.09%, respectively. This work demonstrates the importance of a knowledge of solution chemistry in investigating the desorption of radionuclides

  8. Experimental measurements of the solubilities of selected long-lived fission products, activation products and actinide daughters under high pH conditions

    International Nuclear Information System (INIS)

    Pilkington, N.J.; Shadbolt, P.J.; Wilkins, J.D.

    1988-05-01

    Solubility measurements of several elements have been attempted under high pH and oxic conditions in a range of concrete leachates. The elements investigated were niobium, tin, selenium, lead and thorium. (author)

  9. Growth and Tissue Elemental Composition Response of Butterhead Lettuce (Lactuca sativa, cv. Flandria to Hydroponic Conditions at Different pH and Alkalinity

    Directory of Open Access Journals (Sweden)

    Tyler S. Anderson

    2017-07-01

    Full Text Available Biomass and tissue elemental differences were quantified for lettuce grown in deep-water conventional hydroponic conditions at two pH and alkalinity conditions. Nutrient solutions were created using inorganic salts and either reverse osmosis (RO water or municipal water with high alkalinity. Three treatments were evaluated: (a nutrient solution created with reverse osmosis (RO water and maintained at pH 5.8 (H5; (b same as H5 but maintained at pH 7.0 (H7; and (c nutrient solution created using municipal water and maintained at pH 7.0, referred to as HA7. Averaged across three trials, the HA7 and H7 treatments produced 26% less shoot fresh weight (FW than the H5 treatment with an 18% reduction in dry weight (DW. The H5 treatment had the least biomass in root FW and DW. In tissue elemental analyses, both the pH 7.0 treatments showed lower concentrations than H5 in Cu, N, Mo, and Sr, and increased concentrations in Ba, Mg, Na, and Zn. There were no differences in Al, C, Ca, Fe, K, Mn, Ni, P, S, and Si concentrations among treatments (p = 0.05. The results from this experiment can be used to isolate the effects of pH and alkalinity in aquaponic conditions where pH and alkalinity will mimic HA7 conditions.

  10. Effects of Powder Attributes and Laser Powder Bed Fusion (L-PBF) Process Conditions on the Densification and Mechanical Properties of 17-4 PH Stainless Steel

    Science.gov (United States)

    Irrinki, Harish; Dexter, Michael; Barmore, Brenton; Enneti, Ravi; Pasebani, Somayeh; Badwe, Sunil; Stitzel, Jason; Malhotra, Rajiv; Atre, Sundar V.

    2016-03-01

    The effects of powders attributes (shape and size distribution) and critical processing conditions (energy density) on the densification and mechanical properties of laser powder bed fusion (L-PBF) 17-4 PH stainless steel were studied using four types of powders. The % theoretical density, ultimate tensile strength and hardness of both water- and gas-atomized powders increased with increased energy density. Gas-atomized powders showed superior densification and mechanical properties when processed at low energy densities. However, the % theoretical density and mechanical properties of water-atomized powders were comparable to gas-atomized powders when sintered at a high energy density of 104 J/mm3. An important result of this study was that, even at high % theoretical density (97% ± 1%), the properties of as-printed parts could vary over a relatively large range (UTS: 500-1100 MPa; hardness: 25-39 HRC; elongation: 10-25%) depending on powder characteristics and process conditions. The results also demonstrate the feasibility of using relatively inexpensive water-atomized powders as starting raw material instead of the typically used gas-atomized powders to fabricate parts using L-PBF techniques by sintering at high energy densities.

  11. Stability of Anthocyanins and Their Degradation Products from Cabernet Sauvignon Red Wine under Gastrointestinal pH and Temperature Conditions.

    Science.gov (United States)

    Yang, Ping; Yuan, Chunlong; Wang, Hua; Han, Fuliang; Liu, Yangjie; Wang, Lin; Liu, Yang

    2018-02-07

    This study investigated the stability of wine anthocyanins under simulated gastrointestinal pH and temperature conditions, and further studied the evolution of anthocyanin degradation products through simulated digestive conditions. The aim of this study was to investigate the relation between anthocyanins' structure and their digestive stability. Results showed that a total of 22 anthocyanins were identified in wine and most of these anthocyanins remained stable under simulated gastric digestion process. However, a dramatic concentration decrease happened to these anthocyanins during simulated intestinal digestion. The stability of anthocyanins in digestive process appeared to be related to their structure. The methoxy group in the B-ring enhanced the stability of anthocyanins, whereas hydroxyl group resulted in a reduction of their stability. Acylation decreased the stability of malvidin 3- O -glucoside. Pyruvic acid conjugation enhanced the structural stability of pyranoanthocyanins, whereas acetaldehyde attachment weakened their stability. A commercial malvidin 3- O -glucoside standard was used to investigate anthocyanin degradation products under simulated digestion process, and syringic acid, protocatechuic acid and vanillic acid were confirmed to be the degradation products via anthocyanin chalcone conversion path. Gallic acid, protocatechuic acid, vanillic acid, syringic acid, and p -coumaric acid in wine experienced a significant concentration decrease during digestion process. However, wine model solution revealed that phenolic acids remained stable under gastrointestinal conditions, except gallic acid.

  12. Stability of Anthocyanins and Their Degradation Products from Cabernet Sauvignon Red Wine under Gastrointestinal pH and Temperature Conditions

    Directory of Open Access Journals (Sweden)

    Ping Yang

    2018-02-01

    Full Text Available This study investigated the stability of wine anthocyanins under simulated gastrointestinal pH and temperature conditions, and further studied the evolution of anthocyanin degradation products through simulated digestive conditions. The aim of this study was to investigate the relation between anthocyanins’ structure and their digestive stability. Results showed that a total of 22 anthocyanins were identified in wine and most of these anthocyanins remained stable under simulated gastric digestion process. However, a dramatic concentration decrease happened to these anthocyanins during simulated intestinal digestion. The stability of anthocyanins in digestive process appeared to be related to their structure. The methoxy group in the B-ring enhanced the stability of anthocyanins, whereas hydroxyl group resulted in a reduction of their stability. Acylation decreased the stability of malvidin 3-O-glucoside. Pyruvic acid conjugation enhanced the structural stability of pyranoanthocyanins, whereas acetaldehyde attachment weakened their stability. A commercial malvidin 3-O-glucoside standard was used to investigate anthocyanin degradation products under simulated digestion process, and syringic acid, protocatechuic acid and vanillic acid were confirmed to be the degradation products via anthocyanin chalcone conversion path. Gallic acid, protocatechuic acid, vanillic acid, syringic acid, and p-coumaric acid in wine experienced a significant concentration decrease during digestion process. However, wine model solution revealed that phenolic acids remained stable under gastrointestinal conditions, except gallic acid.

  13. A cow-level association of ruminal pH on body condition score, serum beta-hydroxybutyrate and postpartum disorders in Thai dairy cattle.

    Science.gov (United States)

    Chaidate, Inchaisri; Somchai, Chanpongsang; Jos, Noordhuizen; Henk, Hogeveen

    2014-09-01

    Subacute ruminal acidosis in dairy cows occurs when ruminal pH is below about 5.5. However, the exact threshold level of ruminal pH affecting cow health is still in debate. This investigation was carried out in 505 cows within 31 farms. The postpartum disorders, including dystocia, retained placenta, anestrus, cystic ovary, metritis, clinical mastitis and lameness, were analyzed. Ruminal pH, serum beta-hydroxy butyrate (SBHB), serum urea nitrogen and body condition score (BCS) were measured once during the 3 to 6 weeks postpartum, while BCS was determined once more at 1 week before calving. Ruminal pH was determined by ruminocentesis technique. The ruminal pH was evaluated to study the association with BCS, SBHB and postpartum disorders using linear regression in a generalized linear mixed model with farm as a random effect. The results show that low ruminal pH was associated with dystocia, metritis and lameness. Moreover, a low ruminal pH can be found in cows with a high loss of BCS after calving and also in cows with low SBHB postpartum. These findings confirmed the feasibility of the ruminocentesis technique and the association of low ruminal pH on various postpartum disorders at the individual cow level. However, the consequences of low ruminal pH on dairy cow health still needs more exploration for a better understanding of the physiological mechanisms. © 2014 Japanese Society of Animal Science.

  14. Varied Human Tolerance to the Combined Conditions of Low Contrast and Diminished Luminance: A Quasi-Meta Analysis

    Science.gov (United States)

    2017-08-30

    conditions (e.g., dry eyes , mild cataractous conditions, Stevens-Johnson Syndrome ) using CS alone as the performance index. More commonly, it has been...subjects tested under conditions of spherical blur, astigmatic blur, low luminance, and one eye vs. two eyes ...conditions). The vast majority of past mesopic visual performance studies were predominantly isolated to evaluations of various eye disease

  15. Highly effective degradation of selected groups of organic compounds by cavitation based AOPs under basic pH conditions.

    Science.gov (United States)

    Gągol, Michał; Przyjazny, Andrzej; Boczkaj, Grzegorz

    2018-07-01

    Cavitation has become on the most often applied methods in a number of industrial technologies. In the case of oxidation of organic pollutants occurring in the aqueous medium, cavitation forms the basis of numerous advanced oxidation processes (AOPs). This paper presents the results of investigations on the efficiency of oxidation of the following groups of organic compounds: organosulfur, nitro derivatives of benzene, BTEX, and phenol and its derivatives in a basic model effluent using hydrodynamic and acoustic cavitation combined with external oxidants, i.e., hydrogen peroxide, ozone and peroxone. The studies revealed that the combination of cavitation with additional oxidants allows 100% oxidation of the investigated model compounds. However, individual treatments differed with respect to the rate of degradation. Hydrodynamic cavitation aided by peroxone was found to be the most effective treatment (100% oxidation of all the investigated compounds in 60 min). When using hydrodynamic and acoustic cavitation alone, the effectiveness of oxidation was diversified. Under these conditions, nitro derivatives of benzene and phenol and its derivatives were found to be resistant to oxidation. In addition, hydrodynamic cavitation was found to be more effective in degradation of model compounds than acoustic cavitation. The results of investigations presented in this paper compare favorably with the investigations on degradation of organic contaminants using AOPs under conditions of basic pH published thus far. Copyright © 2018 Elsevier B.V. All rights reserved.

  16. Mode of de-esterification of alkaline and acidic pectin methyl esterases at different pH conditions.

    Science.gov (United States)

    Duvetter, Thomas; Fraeye, Ilse; Sila, Daniel N; Verlent, Isabel; Smout, Chantal; Hendrickx, Marc; Van Loey, Ann

    2006-10-04

    Highly esterified citrus pectin was de-esterified at pH 4.5 and 8.0 by a fungal pectin methyl esterase (PME) that was shown to have an acidic isoelectric pH (pI) and an acidic pH optimum and by a plant PME that was characterized by an alkaline pI and an alkaline pH optimum. Interchain and intrachain de-esterification patterns were studied by digestion of the pectin products with endo-polygalacturonase and subsequent analysis using size exclusion and anion-exchange chromatography. No effect of pH was observed on the de-esterification mode of either of the two enzymes. Acidic, fungal PME converted pectin according to a multiple-chain mechanism, with a limited degree of multiple attack at the intrachain level, both at pH 4.5 and at pH 8.0. A multiple-attack mechanism, with a high degree of multiple attack, was more appropriate to describe the action mode of alkaline, plant PME, both at pH 4.5 and at pH 8.0.

  17. The Influence of Polymerization Condition to Optical Properties of Poly-o-toludine Films for PH Sensor Application

    Directory of Open Access Journals (Sweden)

    Yanti Sabarinah

    2006-04-01

    Full Text Available Properties of poly-o-toludine film strongly bonded to non polar substrate was studied for application as optical pH sensor. Characterization of film in various pH value is carried out by recording absorbance curve using uv-visible spectrophotometer. All poly-o-toluidine film was then found to be applicable as optical pH sensor in the pH range of 2.0- 6.0. Further computational processing by means of curve fitting into logaritmic trend will allow expansion of measurement to the pH range of 2.0-8.0. Sensitivity of pH response was highest in poly-o-toluidine film fabricate at HCl 1.0 M and at 12 hours of dipping time. This paper also studied hysteresis effect in pH response. It was concluded that poly-o-toluidine salt exposed to basic pH will not be easily regenerated. For this reason, poly-o-toluidine film will only be suitable for single usage of pH measurement.

  18. Leaching and accumulation of trace elements in sulfate reducing granular sludge under concomitant thermophilic and low pH conditions

    KAUST Repository

    Gonzalez-Gil, Graciela; Lopes, Sí lvia I C; Saikaly, Pascal; Lens, Piet Nl L

    2012-01-01

    The leaching and/or accumulation of trace elements in sulfate reducing granular sludge systems was investigated. Two thermophilic up-flow anaerobic sludge bed (UASB) reactors operated at pH 5 were fed with sucrose (4gCODl reactor -1d -1) and sulfate at different COD/SO 4 2- ratios. During the start-up of such acidogenic systems, an initial leaching of trace elements from the inoculum sludge occurred regardless of trace elements supplementation in the reactor influent. The granular sludge maintained the physical structure despite high Fe leaching. After start-up and nonetheless the acidic conditions, Co, Ni, Cu, Zn, Mo and Se were retained or accumulated by the sludge when added. Particularly, Ni and Co accumulated in the carbonates and exchangeable fractions ensuring potential bioavailability. Otherwise, the initial stock in the inoculum sludge sufficed to operate the process for nearly 1year without supplementation of trace elements and no significant sludge wash-out occurred. © 2012 Elsevier Ltd.

  19. Leaching and accumulation of trace elements in sulfate reducing granular sludge under concomitant thermophilic and low pH conditions

    KAUST Repository

    Gonzalez-Gil, Graciela

    2012-12-01

    The leaching and/or accumulation of trace elements in sulfate reducing granular sludge systems was investigated. Two thermophilic up-flow anaerobic sludge bed (UASB) reactors operated at pH 5 were fed with sucrose (4gCODl reactor -1d -1) and sulfate at different COD/SO 4 2- ratios. During the start-up of such acidogenic systems, an initial leaching of trace elements from the inoculum sludge occurred regardless of trace elements supplementation in the reactor influent. The granular sludge maintained the physical structure despite high Fe leaching. After start-up and nonetheless the acidic conditions, Co, Ni, Cu, Zn, Mo and Se were retained or accumulated by the sludge when added. Particularly, Ni and Co accumulated in the carbonates and exchangeable fractions ensuring potential bioavailability. Otherwise, the initial stock in the inoculum sludge sufficed to operate the process for nearly 1year without supplementation of trace elements and no significant sludge wash-out occurred. © 2012 Elsevier Ltd.

  20. Generation of synthetic surface electromyography signals under fatigue conditions for varying force inputs using feedback control algorithm.

    Science.gov (United States)

    Venugopal, G; Deepak, P; Ghosh, Diptasree M; Ramakrishnan, S

    2017-11-01

    Surface electromyography is a non-invasive technique used for recording the electrical activity of neuromuscular systems. These signals are random, complex and multi-component. There are several techniques to extract information about the force exerted by muscles during any activity. This work attempts to generate surface electromyography signals for various magnitudes of force under isometric non-fatigue and fatigue conditions using a feedback model. The model is based on existing current distribution, volume conductor relations, the feedback control algorithm for rate coding and generation of firing pattern. The result shows that synthetic surface electromyography signals are highly complex in both non-fatigue and fatigue conditions. Furthermore, surface electromyography signals have higher amplitude and lower frequency under fatigue condition. This model can be used to study the influence of various signal parameters under fatigue and non-fatigue conditions.

  1. A SVDD and K-Means Based Early Warning Method for Dual-Rotor Equipment under Time-Varying Operating Conditions

    Directory of Open Access Journals (Sweden)

    Zhinong Jiang

    2018-01-01

    Full Text Available Under frequently time-varying operating conditions, equipment with dual rotors like gas turbines is influenced by two rotors with different rotating speeds. Alarm methods of fixed threshold are unable to consider the influences of time-varying operating conditions. Hence, those methods are not suitable for monitoring dual-rotor equipment. An early warning method for dual-rotor equipment under time-varying operating conditions is proposed in this paper. The influences of time-varying rotating speeds of dual rotors on alarm thresholds have been considered. Firstly, the operating conditions are divided into several limited intervals according to rotating speeds of dual rotors. Secondly, the train data within each interval is processed by SVDD and the allowable ranges (i.e., the alarm threshold of the vibration are determined. The alarm threshold of each interval of operating conditions is obtained. The alarm threshold can be expressed as a sphere, whose controlling parameters are the coordinate of the center and the radius. Then, the cluster center of the test data, whose alarm state is to be judged, can be extracted through K-means. Finally, the alarm state can be obtained by comparing the cluster center with the corresponding sphere. Experiments are conducted to validate the proposed method.

  2. Microbial reduction of Fe(III) in the presence of oxygen under low pH conditions

    Energy Technology Data Exchange (ETDEWEB)

    Kusel, K.; Roth, U.; Drake, H.L. [University of Bayreuth, Bayreuth (Germany)

    2002-07-01

    In acidic, coal mining lake sediments, facultatively anaerobic Acidiphilium species are probably involved in the reduction of Fe(III). Previous results indicate that these bacteria can co-respire O{sub 2} and Fe(III). In this study, we investigated the capacity of the sediment microbiota to reduce Fe(III) in the presence of O{sub 2} at pH 3. In sediment microcosms with 4% O{sub 2} in the headspace, the concentration of Fe(II) increased at a rate of 1.03 {mu}mol (g wet sediment){sup -1} day{sup -1} within the first 7 days of incubation which was similar to the rate obtained with controls incubated under anoxic conditions. However, in microcosms incubated under air, Fe(II) was consumed after a lag phase of 8 h with a rate of 2.66 {mu}mol (g wet sediment){sup -1} day{sup -1}. Acidiphilium cryptum JF-5, isolated from this sediment, reduced soluble Fe(III) with either 4 or 21% O{sub 2} in the headspace, and concomitantly consumed O{sub 2}. However, the rate of Fe(II) formation normalized for cell density decreased under oxic conditions. Schwertmannite, the predominant Fe(III)-mineral of this sediment, was also reduced by A. cryptum JF-5 under oxic conditions. The rate of Fe(II) formation by A. cryptum JF-5 decreased after transfer from preincubation under air in medium lacking Fe(III). Acidiphilium cryptum JF-5 did not form Fe(II) when preincubated under air and transferred to anoxic medium containing Fe(III) and chloramphenicol, an inhibitor of protein synthesis. These results indicate that: (i) the reduction of Fe(III) can occur at low O{sub 2} concentrations in acidic sediments; (ii) Fe(II) can be oxidized at O{sub 2} concentrations near saturation; and (iii) the enzyme(s) responsible for the reduction of Fe(III) in A. cryptum JF-5 are not constitutive.

  3. Biodiesel production process optimization and characterization to assess the suitability of the product for varied environmental conditions

    Energy Technology Data Exchange (ETDEWEB)

    Eevera, T.; Rajendran, K.; Saradha, S. [Department of Biotechnology, Periyar Maniammai University, Periyar Nagar, Vallam, Thanjavur, Tamilnadu 613 403 (India)

    2009-03-15

    In this study, both edible (coconut oil, palm oil, groundnut oil, and rice bran oil) and non-edible oils (pongamia, neem and cotton seed oil) were used to optimize the biodiesel production process variables like catalyst concentration, amount of methanol required for reaction, reaction time and reaction temperature. The fuel properties like specific gravity, moisture content, refractive index, acid value, iodine number, saponification value and peroxide value were estimated. Based on the cetane number and iodine value, the methyl esters obtained from palm and coconut oils were not suitable to use as biodiesel in cold weather conditions, but for hot climate condition biodiesel obtained from the remaining oil sources is suitable. (author)

  4. Analytical solution for multi-species contaminant transport in finite media with time-varying boundary conditions

    Science.gov (United States)

    Most analytical solutions available for the equations governing the advective-dispersive transport of multiple solutes undergoing sequential first-order decay reactions have been developed for infinite or semi-infinite spatial domains and steady-state boundary conditions. In this work we present an ...

  5. Foam Core Particleboards with Intumescent FRT Veneer: Cone Calorimeter Testing With Varying Adhesives, Surface Layer Thicknesses, and Processing Conditions

    Science.gov (United States)

    Mark A. Dietenberger; Johannes Welling; Ali Shalbafan

    2014-01-01

    Intumescent FRT Veneers adhered to the surface of foam core particleboard to provide adequate fire protection were evaluated by means of cone calorimeter tests (ASTM E1354). The foam core particleboards were prepared with variations in surface layer treatment, adhesives, surface layer thicknesses, and processing conditions. Ignitability, heat release rate profile, peak...

  6. Spinning in different directions: western rock lobster larval condition varies with eddy polarity, but does their diet?

    OpenAIRE

    O'Rorke, R.; Jeffs, A. G.; Wang, M.; Waite, A. M.; Beckley, L. E.; Lavery, S. D.

    2015-01-01

    Larvae of the western rock lobster (Panulirus cygnus) that occur in the south-east Indian Ocean offshore of Western Australia have been found to be in poorer nutritional condition in anticyclonic compared with cyclonic mesoscale eddies. The reason for this is unknown, but culture-based experiments have shown that diet composition and water temperature are key determinants of phyllosoma health and survival. Whether differences in prey composition are the cause of poor phyllosoma co...

  7. Effects of varying environmental conditions on emissivity spectra of bulk lunar soils: Application to Diviner thermal infrared observations of the Moon

    Science.gov (United States)

    Donaldson Hanna, K. L.; Greenhagen, B. T.; Patterson, W. R.; Pieters, C. M.; Mustard, J. F.; Bowles, N. E.; Paige, D. A.; Glotch, T. D.; Thompson, C.

    2017-02-01

    Currently, few thermal infrared measurements exist of fine particulate (samples (e.g. minerals, mineral mixtures, rocks, meteorites, and lunar soils) measured under simulated lunar conditions. Such measurements are fundamental for interpreting thermal infrared (TIR) observations by the Diviner Lunar Radiometer Experiment (Diviner) onboard NASA's Lunar Reconnaissance Orbiter as well as future TIR observations of the Moon and other airless bodies. In this work, we present thermal infrared emissivity measurements of a suite of well-characterized Apollo lunar soils and a fine particulate (sample as we systematically vary parameters that control the near-surface environment in our vacuum chamber (atmospheric pressure, incident solar-like radiation, and sample cup temperature). The atmospheric pressure is varied between ambient (1000 mbar) and vacuum (radiation is varied between 52 and 146 mW/cm2, and the sample cup temperature is varied between 325 and 405 K. Spectral changes are characterized as each parameter is varied, which highlight the sensitivity of thermal infrared emissivity spectra to the atmospheric pressure and the incident solar-like radiation. Finally spectral measurements of Apollo 15 and 16 bulk lunar soils are compared with Diviner thermal infrared observations of the Apollo 15 and 16 sampling sites. This comparison allows us to constrain the temperature and pressure conditions that best simulate the near-surface environment of the Moon for future laboratory measurements and to better interpret lunar surface compositions as observed by Diviner.

  8. Evaluation of citric acid and GDL in the recovery at different pH levels of Clostridium sporogenes PA 3679 spores subjected to HTST treatment conditions.

    Science.gov (United States)

    Silla Santos, M H; Torres Zarzo, J

    1996-04-01

    Spores of Clostridium sporogenes PA 3679 were treated at different temperatures (121, 126, 130 and 135 degrees C) in white asparagus purée (pH 5.8) and acidified with glucono-delta-lactone (GDL) and citric acid to pH levels of 5.5, 5.0 and 4.5. Afterwards, the spores were recovered in MPA3679 medium in various conditions: unacidified (pH 7.5), acidified with GDL (500 ppm) and acidified with citric acid (500 and 250 ppm) to pH levels of 6.5, 6.0 and 5.0. The results indicated that the pH levels, concentration and type of acid used act synergistically rather than independently. Citric acid has a stronger inhibiting effect than GDL on the recovery of C. sporogenes PA 3679 spores. At the higher heat treatments (130 and 135 degrees C) the major injury on the spores sensitize more than against the acids and low pH values.

  9. Evolution of deformation structures under varying loading conditions followed in situ by high angular resolution 3DXRD

    DEFF Research Database (Denmark)

    Pantleon, Wolfgang; Wejdemann, Christian; Jakobsen, B.

    2009-01-01

    copper to different loading conditions are presented: during uninterrupted tensile deformation, formation of subgrains can be observed concurrently with broadening of the Bragg reflection shortly after onset of plastic deformation. With continued tensile deformation, the subgrain structure develops...... intermittently. When the traction is terminated, stress relaxation occurs and number, size and orientation of subgrains are found to be constant. The subgrain structure freezes and only a minor clean-up of the dislocation structure is observed. When changing the tensile direction after pre-deformation in tension...

  10. Effect of the temperature, pH and irradiance on the photosynthetic activity by Scenedesmus obtusiusculus under nitrogen replete and deplete conditions.

    Science.gov (United States)

    Cabello, Juan; Toledo-Cervantes, Alma; Sánchez, León; Revah, Sergio; Morales, Marcia

    2015-04-01

    This paper evaluates the effect of the irradiance, pH and temperature on the photosynthetic activity (PA) of Scenedesmus obtusiusculus under N-replete and N-deplete conditions through oxygen measurements. The highest PA values were 160 mgO2 gb(-1) h(-1) at 620 μmol m(-2) s(-1), 35 °C and pH of 8 under N-replete conditions and 3.3 mgO2 gb(-1) h(-1) at 100 μmol m(-2) s(-1), 28.5 °C and pH of 5.5 for N-deplete conditions. Those operation conditions were tested in a flat-panel photobioreactor. The biomass productivity was 0.97 gb L(-1) d(-1) under N-replete conditions with a photosynthetic efficiency (PE) of 4.4% yielding 0.85 gb mol photon(-1). Similar biomass productivity was obtained under N-deplete condition; and the lipid productivity was 0.34 gL L(-1) d(-1) with a PE of 7.8% yielding 0.39 gL mol photon(-1). The apparent activation and deactivation energies were 16.1 and 30 kcal mol(-1), and 11.9 and 15.3 kcal mol(-1), for N-replete and N-deplete conditions, respectively. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Effects of cell condition, pH, and temperature on lead, zinc, and copper sorption to Acidithiobacillus caldus strain BC13

    International Nuclear Information System (INIS)

    Aston, John E.; Apel, William A.; Lee, Brady D.; Peyton, Brent M.

    2010-01-01

    Research highlights: →At. caldus sorbs lead, zinc, and copper across a range of pH and temperature. →At. caldus shows a relatively high sorption capacity for zinc and copper at low pH. → Lead, zinc, and copper sorption decreases in tertiary mixtures. → Copper appears to sorb via a different mechanism(s) than lead or zinc. - Abstract: This study describes the effects of cell condition, pH, and temperature on lead, zinc, and copper sorption to Acidithiobacillus caldus strain BC13 with a Langmuir model. Copper exhibited the highest loading capacity, 4.76 ± 0.28 mmol g -1 , to viable cells at pH 5.5. The highest k L (binding-site affinity) observed was 61.2 ± 3.0 L mmol -1 to dehydrated cells at pH 4.0. The pHs that maximized loading capacities and binding-site affinities were generally between 4.0 and 5.5, where the sum of free-proton and complexed-metal concentrations was near a minimum. Of additional importance, lead, zinc, and copper sorbed to viable cells at pH values as low as 1.5. Previous studies with other acidithiobacilli did not measure viable-cell sorption below pH 4.0. In separate experiments, desorption studies showed that far less copper was recovered from viable cells than any other metal or cell condition, suggesting that uptake may play an important role in copper sorption by At. caldus strain BC13. To reflect an applied system, the sorption of metal mixtures was also studied. In these experiments, lead, zinc, and copper sorption from a tertiary mixture were 40.2 ± 4.3%, 28.7 ± 3.8%, and 91.3 ± 3.0%, respectively, of that sorbed in single-metal systems.

  12. Alternatives for biosurfactants and bacteriocins extraction from Lactococcus lactis cultures produced under different pH conditions.

    Science.gov (United States)

    Rodríguez, N; Salgado, J M; Cortés, S; Domínguez, J M

    2010-08-01

    Study of the potential of Lactococcus lactis CECT-4434 as a biosurfactants and nisin (the only bacteriocin allowed to be used in the food industry) producer for industrial applications, exploiting the possibility of recovering separately both metabolites, taking into account that L. lactis is an interesting micro-organism with several applications in the food industry because it is recognized as GRAS. The results showed the ability of this strain to produce cell-bound biosurfactants, under controlled pH, and cell-bound biosurfactants and bacteriocins, when pH was not controlled. Three extraction procedures were designed to separately recover these substances. The strain L. lactis CECT-4434 showed to be a cell-bound biosurfactants and bacterocins producer when fermentations were carried out under uncontrolled pH. Both products can be recovered separately. Development of a convenient tool for the extraction of cell-bound biosurfactants and bacteriocins from the fermentation broth.

  13. Investigating the emerging role of comparative proteomics in the search for new biomarkers of metal contamination under varying abiotic conditions

    Energy Technology Data Exchange (ETDEWEB)

    Vellinger, Céline, E-mail: celine.vellinger@gmail.com [Laboratoire Interdisciplinaire des Environnements Continentaux (LIEC), CNRS UMR 7360, Université de Lorraine – Metz (France); Sohm, Bénédicte, E-mail: benedicte.sohm@univ-lorraine.fr [Laboratoire Interdisciplinaire des Environnements Continentaux (LIEC), CNRS UMR 7360, Université de Lorraine – Metz (France); Parant, Marc, E-mail: marc.parant@univ-lorraine.fr [Laboratoire Interdisciplinaire des Environnements Continentaux (LIEC), CNRS UMR 7360, Université de Lorraine – Metz (France); Immel, Françoise, E-mail: Francoise.Immel@u-bourgogne.fr [Biogéosciences, CNRS UMR 6282, Université de Bourgogne – Dijon (France); Usseglio-Polatera, Philippe, E-mail: philippe.usseglio-polatera@univ-lorraine.fr [Laboratoire Interdisciplinaire des Environnements Continentaux (LIEC), CNRS UMR 7360, Université de Lorraine – Metz (France)

    2016-08-15

    This study aims at investigating the potential use of comparative proteomics as a multi-marker approach of metal contamination, taking into account the potential confounding effect of water temperature. The major objective was to identify combinations of proteins specifically responding to a given metal, even if included in a metal mixture. The diagnostic approach was performed via the comparative analysis of protein expression on spot mapping provided by adult males of Gammarus pulex (Amphipoda, Crustacea) respectively exposed to arsenate (As), cadmium (Cd) or a binary mixture of these metals (AsCd) at three realistic temperatures (5, 10 and 15 °C). Proteomic expression analysis was performed by Differential in-Gel Electrophoresis (2D-DiGE), and completed by an adapted inferential statistical approach. Combinations of under/over-expressed protein spots discriminated the metal identity. However, none of these spots discriminated both the individual metal effect (As or Cd) and its effect in metal mixture (AsCd) whatever the tested temperature. Some limits of the two-dimensional analysis of protein spot maps in G. pulex have been highlighted: (i) the presence of contaminating peptides and/or abundant “déja-vu” proteins which can mask the responses of other proteins of interest or (ii) the presence of post-translational modifications. An optimization of the experimental design (especially during the sample preparation) has been described for future investigations. This study has also highlighted (i) the importance of precisely identifying the protein spots of interest to avoid erroneous interpretations in terms of action mechanisms of chemicals and (ii) the importance of working under controlled laboratory conditions with a temperature close to 10 °C. In such conditions, we have demonstrated a higher impact of As than Cd on the energetic metabolism of Gammarus. This As impact is reduced in AsCd mixture confirming the antagonistic interaction of this binary

  14. Investigating the emerging role of comparative proteomics in the search for new biomarkers of metal contamination under varying abiotic conditions

    International Nuclear Information System (INIS)

    Vellinger, Céline; Sohm, Bénédicte; Parant, Marc; Immel, Françoise; Usseglio-Polatera, Philippe

    2016-01-01

    This study aims at investigating the potential use of comparative proteomics as a multi-marker approach of metal contamination, taking into account the potential confounding effect of water temperature. The major objective was to identify combinations of proteins specifically responding to a given metal, even if included in a metal mixture. The diagnostic approach was performed via the comparative analysis of protein expression on spot mapping provided by adult males of Gammarus pulex (Amphipoda, Crustacea) respectively exposed to arsenate (As), cadmium (Cd) or a binary mixture of these metals (AsCd) at three realistic temperatures (5, 10 and 15 °C). Proteomic expression analysis was performed by Differential in-Gel Electrophoresis (2D-DiGE), and completed by an adapted inferential statistical approach. Combinations of under/over-expressed protein spots discriminated the metal identity. However, none of these spots discriminated both the individual metal effect (As or Cd) and its effect in metal mixture (AsCd) whatever the tested temperature. Some limits of the two-dimensional analysis of protein spot maps in G. pulex have been highlighted: (i) the presence of contaminating peptides and/or abundant “déja-vu” proteins which can mask the responses of other proteins of interest or (ii) the presence of post-translational modifications. An optimization of the experimental design (especially during the sample preparation) has been described for future investigations. This study has also highlighted (i) the importance of precisely identifying the protein spots of interest to avoid erroneous interpretations in terms of action mechanisms of chemicals and (ii) the importance of working under controlled laboratory conditions with a temperature close to 10 °C. In such conditions, we have demonstrated a higher impact of As than Cd on the energetic metabolism of Gammarus. This As impact is reduced in AsCd mixture confirming the antagonistic interaction of this binary

  15. An empirical assessment of driver motivation and emotional states in perceived safety margins under varied driving conditions.

    Science.gov (United States)

    Zhang, Yu; Kaber, David B

    2013-01-01

    Motivation models in driving behaviour postulate that driver motives and emotional states dictate risk tolerance under various traffic conditions. The present study used time and driver performance-based payment systems to manipulate motivation and risk-taking behaviour. Ten participants drove to a predefined location in a simulated driving environment. Traffic patterns (density and velocity) were manipulated to cause driver behaviour adjustments due to the need to conform with the social norms of the roadway. The driving environment complexity was investigated as a mediating factor in risk tolerance. Results revealed the performance-based payment system to closely relate to risk-taking behaviour as compared with the time-based payment system. Drivers conformed with social norms associated with specific traffic patterns. Higher roadway complexity led to a more conservative safety margins and speeds. This research contributes to the further development of motivational models of driver behaviour. This study provides empirical justification for two motivation factors in driver risk-taking decisions, including compliance with social norm and emotions triggered by incentives. Environment complexity was identified as a mediating factor in motivational behaviour model. This study also recommended safety margin measures sensitive to changes in driver risk tolerance.

  16. Modulating the phenology and yield of camelina sativa L. by varying sowing dates under water deficit stress conditions

    Directory of Open Access Journals (Sweden)

    Ejaz Ahmad Waraich

    2017-05-01

    Full Text Available Camelina (Camelina sativa L. an oilseed crop has emerged as a potential source for biofuels and bio-products. Camelina is an economic crop due to its less requirements of agronomic inputs as compared to other oilseed crops. However, it is direly required to evaluate the adaptability of camelina and characterize its production potential. Therefore, a pot experiment was carried out in rain out shelter at the Department of Agronomy, University of Agriculture, Faisalabad, Pakistan to optimize appropriate sowing date with respect to growth and yield potential of different genotypes of camelina under drought stress. Completely randomized design with factorial arrangements was adopted. Three sowing dates with the difference of 10 days (November 13 th, 23rd and December 03rd, two water regimes (100% FC and 60% FC and two camlena genotypes (611 and 618 were used in this experiment. Results indicated that camelina growth and yield related traits were significantly influenced by difference in sowing dates and water regimes. Maximum leaf area index (LAI, crop growth rate (CGR, leaf area duration (LAD, net assimilation rate (NAR and yield related traits were recorded with early sowing (13th November which was followed by sowing on 23rd November and least values of these variables were recorded in late sowing (December 03rd. Plants grown under water deficit conditions (60% FC showed the decreased values of LAI, CGR, LAD, NAR and yield related attributes as compared to normally irrigated plants (100% FC. However, the response of genotypes of camelina 611 and 618 remained statistically similar to each other.

  17. Leaching and accumulation of trace elements in sulfate reducing granular sludge under concomitant thermophilic and low pH conditions

    NARCIS (Netherlands)

    Gonzalez-Gil, G.; Lopes, S.I.C.; Saikaly, P.E.; Lens, P.N.L.

    2012-01-01

    The leaching and/or accumulation of trace elements in sulfate reducing granular sludge systems was investigated. Two thermophilic up-flow anaerobic sludge bed (UASB) reactors operated at pH 5 were fed with sucrose (4 g COD l(reactor)(-1) d(-1)) and sulfate at different COD/SO42- ratios. During the

  18. Characterization of citrus pectin samples extracted under different conditions: influence of acid type and pH of extraction

    Science.gov (United States)

    Kaya, Merve; Sousa, António G.; Crépeau, Marie-Jeanne; Sørensen, Susanne O.; Ralet, Marie-Christine

    2014-01-01

    Background and Aims Pectin is a complex macromolecule, the fine structure of which is influenced by many factors. It is used as a gelling, thickening and emulsifying agent in a wide range of applications, from food to pharmaceutical products. Current industrial pectin extraction processes are based on fruit peel, a waste product from the juicing industry, in which thousands of tons of citrus are processed worldwide every year. This study examines how pectin components vary in relation to the plant source (orange, lemon, lime, grapefruit) and considers the influence of extraction conditions on the chemical and macromolecular characteristics of pectin samples. Methods Citrus peel (orange, lemon, lime and grapefruit) from a commercial supplier was used as raw material. Pectin samples were obtained on a bulk plant scale (kilograms; harsh nitric acid, mild nitric acid and harsh oxalic acid extraction) and on a laboratory scale (grams; mild oxalic acid extraction). Pectin composition (acidic and neutral sugars) and physicochemical properties (molar mass and intrinsic viscosity) were determined. Key Results Oxalic acid extraction allowed the recovery of pectin samples of high molecular weight. Mild oxalic acid-extracted pectins were rich in long homogalacturonan stretches and contained rhamnogalacturonan I stretches with conserved side chains. Nitric acid-extracted pectins exhibited lower molecular weights and contained rhamnogalacturonan I stretches encompassing few and/or short side chains. Grapefruit pectin was found to have short side chains compared with orange, lime and lemon. Orange and grapefruit pectin samples were both particularly rich in rhamnogalacturonan I backbones. Conclusions Structural, and hence macromolecular, variations within the different citrus pectin samples were mainly related to their rhamnogalacturonan I contents and integrity, and, to a lesser extent, to the length of their homogalacturonan domains. PMID:25081519

  19. Processes influencing migration of bioavailable organic compounds from polymers - investigated during biotic and abiotic testing under static and non-static conditions with varying S/V-ratios

    DEFF Research Database (Denmark)

    Corfitzen, Charlotte B.; Arvin, Erik; Albrechtsen, Hans-Jørgen

    . The bioavailable migration from the polymer surface was influence by diffusion over the solid-liquid boundary layer under sterile conditions, which resulted in an inversely proportionally relationship between bioavailable migration expressed per unit surface area of material and the surface to volume ratio (S/V-ratio...... the effect of the boundary layer, since bioavailable migration was continuously consumed by the bacteria. Thus the driving force for the diffusion process was maintained at a maximum, thereby enhancing the bioavailable migration from the material surfaces. Thus neither non-static conditions nor varying S/V-ratios...

  20. Creep rupture properties under varying load/temperature conditions on a nickel-base heat-resistant alloy strengthened by boron addition

    International Nuclear Information System (INIS)

    Tsuji, Hirokazu; Tanabe, Tatsuhiko; Nakajima, Hajime

    1994-01-01

    A series of constant load and temperature creep rupture tests and varying load and temperature creep rupture tests was carried out on Hastelloy XR whose boron content level is 60 mass ppm at 900 and 1000 C in order to examine the behavior of the alloy under varying load and temperature conditions. The life fraction rule completely fails in the prediction of the creep rupture life under varying load and temperature conditions though the rule shows good applicability for Hastelloy XR whose boron content level is below 10 mass ppm. The modified life fraction rule has been proposed based on the dependence of the creep rupture strength on the boron content level of the alloy. The modified rule successfully predicts the creep rupture life under the test conditions from 1000 to 900 C. The trend observed in the tests from 900 to 1000 C can be qualitatively explained by the mechanism that the oxide film which is formed during the prior exposure to 900 C plays the role of the protective barrier against the boron dissipation into the environment. (orig.)

  1. Creep rupture properties under varying load/temperature conditions on a nickel-base heat-resistant alloy strengthened by boron addition

    International Nuclear Information System (INIS)

    Tsuji, Hirokazu; Nakajima, Hajime; Tanabe, Tatsuhiko.

    1993-09-01

    A series of constant load and temperature creep rupture tests and varying load and temperature creep rupture tests was carried out on Hastelloy XR whose boron content level is 60 mass ppm at 900 and 1000degC in order to examine the behavior of the alloy under varying load and temperature conditions. The life fraction rule completely fails in the prediction of the creep rupture life under varying load and temperature conditions though the rule shows good applicability for Hastelloy XR whose boron content level is below 10 mass ppm. The modified life fraction rule has been proposed based on the dependence of the creep rupture strength on the born content level of the alloy. The modified rule successfully predicts the creep rupture life under the test conditions from 1000degC to 900degC. The trend observed in the tests from 900degC to 1000degC can be qualitatively explained by the mechanism that the oxide film which is formed during the prior exposure to 900degC plays the role of the protective barrier against the boron dissipation into the environment. (author)

  2. Stability of poly(N-isopropylacrylamide-co-acrylic acid polymer microgels under various conditions of temperature, pH and salt concentration

    Directory of Open Access Journals (Sweden)

    Zahoor H. Farooqi

    2017-03-01

    Full Text Available This research article describes the colloidal stability of poly(N-isopropylacrylamide-co-acrylic acid [P(NIPAM-co-AAc] polymer microgels with different acrylic acid contents in aqueous medium under various conditions of temperature, pH and sodium chloride concentrations. Three samples of multi-responsive P(NIPAM-co-AAc polymer microgels were synthesized using different amounts of acrylic acid by free radical emulsion polymerization. Dynamic laser light scattering was used to investigate the responsive behavior and stability of the prepared microgels under various conditions of pH, temperature and ionic strength. The microgels were found to be stable at all pH values above the pKa value of acrylic acid moiety in the temperature range from 15 to 60 °C in the presence and absence of sodium chloride. Increase in temperature, salt concentration and decrease in pH causes aggregation and decreases the stability of microgels due to the decrease in hydrophilicity.

  3. The Effect of Saccharomyces Strains and Fermentation Condition on the pH, Foam Property and CO2 Concentration of Non-alcoholic Beer (Ma-al-shaeer

    Directory of Open Access Journals (Sweden)

    S. Sohrabvandi

    2014-12-01

    Full Text Available This study aims to determine the effect of fermentation condition and Saccharomyces strains on the pH, foam property and CO2 concentration of non-alcoholic beer (Ma-al-shaeer. For this, the beer samples were inoculated with four different species of Saccharomyces (Saccharomyces rouxii 70531, S. rouxii 70535, S. ludwigii 3447 and S. cerevisiae 70424 and fermented for 48h in both aerobic and periodic aeration at three different temperatures. Then their pH, CO2 concentration and foam property were analyzed in 12h intervals during 48h fermentation. The results shows that the treatments with 4×107 CFU.ml-1 and periodic aeration at 24˚C showed the greatest decrease in pH, and the treatments with 107 CFU.ml-1 and aerobic-periodic aeration at 4˚C showed the lowest decrease in pH. The highest and lowest amounts of CO2 and foam property were obtained in the treatments with 4×107 CFU.ml-1 inoculation, aerobic condition, and the treatments with 107 CFU.ml-1, periodic aeration, respectively. These results further demonstrated that the highest drop in pH, and the highest ability of producing CO2 and foam were for S. cerevisiae 70424, and the lowest belonged to S. rouxii 70531. The overall outcome of the study points to the fact that physico-chemical properties of Ma-al-shaeer is important from the consumers' point of view. Therefore, S. cerevisiae with 4×107 CFU.ml-1 inoculation and aerobic condition at 4˚C has promising potential for producing Ma-al-shaeer with good physicochemical properties.

  4. Speciation of humic acid and some transition metal ions in presence of each other under alkaline pH conditions

    International Nuclear Information System (INIS)

    Padmanabhan, Hemalatha; Desai, M.V.M.

    1998-12-01

    Humic acid, the major natural organic matter of marine sediments, is extracted and its interactions with Zn, Mn, Co, Fe and Hg are studied. All these elements are found to form cationic, anionic and neutral complexes with humic acid in the pH range of 7 to 13. A novel feature of the work is that the humic acid itself undergoes change in its ionic character in presence of trace elements in the entire pH range studied. The rates of formation of anionic and neutral species for Zn, Mn, Co, Fe and Hg are different for each metal ion. Iron forms predominantly anionic species and the best fit lines of anionic and neutral species are practically parallel to each other. The best fit line of anionic and neutral species have positive slopes in case of Mn and Co. In case of Hg, the best fit line of the anionic species has positive slope and that of neutral species has a negative slope. Thus the abundance and type of species have an interdependence on metal ion, types of species and pH. (author)

  5. THE BIOENERGETICS OF AMMONIA AND HYDROXYLAMINE OXIDATION IN NITROSOMONAS-EUROPAEA AT ACID AND ALKALINE PH

    NARCIS (Netherlands)

    FRIJLINK, MJ; ABEE, T; LAANBROEK, HJ; DEBOER, W; KONINGS, WN

    Autotrophic ammonia oxidizers depend on alkaline or neutral conditions for optimal activity. Below pH 7 growth and metabolic activity decrease dramatically. Actively oxidizing cells of Nitrosomonas europaea do not maintain a constant internal pH when the external pH is varied from 5 to 8. Studies of

  6. Theoretical study on the interactions between chlordecone hydrate and acidic surface groups of activated carbon under basic pH conditions.

    Science.gov (United States)

    Melchor-Rodríguez, Kenia; Gamboa-Carballo, Juan José; Ferino-Pérez, Anthuan; Passé-Coutrin, Nady; Gaspard, Sarra; Jáuregui-Haza, Ulises Javier

    2018-05-01

    A theoretical study of the influence of acidic surface groups (SG) of activated carbon (AC) on chlordecone hydrate (CLDh) adsorption is presented, in order to help understanding the adsorption process under basic pH conditions. A seven rings aromatic system (coronene) with a functional group in the edge was used as a simplified model of AC to evaluate the influence of SG in the course of adsorption from aqueous solution at basic pH conditions. Two SG were modeled in their deprotonated form: carboxyl and hydroxyl (COO - and O - ), interacting with CLDh. In order to model the solvation process, all systems under study were calculated with up to three water molecules. Multiple Minima Hypersurface (MMH) methodology was employed to study the interactions of CLDh with SG on AC using PM7 semiempirical Hamiltonian, to explore the potential energy surfaces of the systems and evaluate their thermodynamic association energies. The re-optimization of representative structures obtained from MMH was done using M06-2X Density Functional Theory. The Quantum Theory of Atoms in Molecules (QTAIM) was used to characterize the interaction types. As result, the association of CLDh with acidic SG at basic pH conditions preferentially occurs between the two alcohol groups of CLDh with COO - and O - groups and by dispersive interactions of chlorine atoms of CLDh with the graphitic surface. On the other hand, the presence of covalent interactions between the negatively charged oxygen of SG and one hydrogen atom of CLDh alcohol groups (O - ⋯HO interactions) without water molecules, was confirmed by QTAIM study. It can be concluded that the interactions of CLDh with acidic SG of AC under basic pH conditions confirms the physical mechanisms of adsorption process. Copyright © 2018 Elsevier Inc. All rights reserved.

  7. Synthesis and HNO Donating Properties of the Piloty's Acid Analogue Trifluoromethanesulphonylhydroxamic acid: Evidence for Quantitative Release of HNO at Neutral pH Conditions.

    Science.gov (United States)

    Adas, Sonya K; Bharadwaj, Vinay; Zhou, Yang; Zhang, Jiuhong; Seed, Alexander J; Brasch, Nicola Elizabeth; Sampson, Paul

    2018-03-11

    Trifluoromethanesulphonylhydroxamic acid, CF3SO2NHOH, is shown to release HNO under physiological pH conditions. A two-step synthesis is presented with the first complete characterization of CF3SO2NHOH. This molecule rapidly decomposes in neutral aqueous solution to cleanly release HNO and CF3SO2-, demonstrated using the HNO traps TXPTS and HOCbl, and by 19F NMR spectroscopy. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. EXAFS study on the neptunium(V) complexation by various humic acids under neutral pH conditions

    Energy Technology Data Exchange (ETDEWEB)

    Sachs, S.; Schmeide, K.; Brendler, V.; Heise, K.H.; Bernhard, G. [Forschungszentrum Rossendorf e.V., Inst. of Radiochemistry, Dresden (Germany); Reich, T. [Forschungszentrum Rossendorf e.V., Inst. of Radiochemistry, Dresden (Germany); Univ. Mainz, Inst. of Nuclear Chemistry (Germany)

    2005-07-01

    The structure of Np(V) humic acid (HA) complexes at pH 7 was studied by extended X-ray absorption fine structure analysis (EXAFS). For the first time, the influence of phenolic OH groups on the complexation of HA and Np(V) in the neutral pH range was investigated using modified HAs with blocked phenolic OH groups and Bio-Rex70, a cation exchange resin having only carboxyl groups as proton exchanging sites. The formation of Np(V) humate complexes was verified by near-infrared (NIR) spectroscopy. Axial Np-O bond distances of 1.84-1.85 Aa were determined for the studied Np(V) humate complexes and the Np(V)-Bio-Rex70 sorbate. In the equatorial plane Np(V) is surrounded by about 3 oxygen atoms with bond lengths of 2.48-2.49 Aa. The comparison of the structural parameters of the Np(V) humates with those of Np(V)-Bio-Rex70 points to the fact that the interaction between HA and Np(V) in the neutral pH range is dominated by carboxylate groups. However, up to now a contribution of phenolic OH groups to the interaction process cannot be excluded completely. The comparison of the obtained structural data for the Np(V) humates to those of Np(V) carboxylates and Np(V) aquo ions reported in the literature indicates that humic acid carboxylate groups predominantly act as monodentate ligands. A differentiation between equatorial coordinated carboxylate groups and water molecules using EXAFS spectroscopy is impossible. (orig.)

  9. Effects of Soil Oxygen Conditions and Soil pH on Remediation of DDT-contaminated Soil by Laccase from White Rot Fungi

    Directory of Open Access Journals (Sweden)

    Yuechun Zhao

    2010-04-01

    Full Text Available High residues of DDT in agricultural soils are of concern because they present serious threats to food security and human health. This article focuses on remediation of DDT-contaminated soil using laccase under different soil oxygen and soil pH conditions. The laboratory experiment results showed significant effects of soil oxygen conditions and soil pH on remediation of DDT-contaminated soil by laccase at the end of a 25-d incubation period. This study found the positive correlation between the concentration of oxygen in soil and the degradation of DDT by laccase. The residue of DDTs in soil under the atmosphere of oxygen decreased by 28.1% compared with the atmosphere of nitrogen at the end of the incubation with laccase. A similar pattern was observed in the remediation of DDT-contaminated soil by laccase under different flooding conditions, the higher the concentrations of oxygen in soil, the lower the residues of four DDT components and DDTs in soils. The residue of DDTs in the nonflooding soil declined by 16.7% compared to the flooded soil at the end of the incubation. The residues of DDTs in soils treated with laccase were lower in the pH range 2.5–4.5.

  10. A review of pH calculation and corrosion product solubilities under PWR primary coolant chemistry conditions

    International Nuclear Information System (INIS)

    Thornton, E.W.; Polley, M.V.

    1986-12-01

    The calculation of high temperature pH in boric acid solutions is discussed and various relationships for the ionisation constant Ksub(w) or ion product Qsub(w) for water are reviewed. It is shown that the boric acid equilibria of Mesmer, Baes and Sweeton remain virtually unaltered when Marshall and Franck's relationship for Ksub(w) is substituted in a re-analysis of Mesmer, Baes and Sweeton's original experimental data. Magnetite solubility data and Westinghouse's studies of iron, nickel and cobalt solubility from mixed ferrites are collated and consideration is given to experimental difficulties which could have contributed to the variability in the data. Thermodynamic model fits have been computerised and used to compare different studies and to determine pH values at which the temperature dependence of solubility is predicted to be zero. Consideration is given to the differing dependences of solubility on dissolved hydrogen concentration in the three model fits. Two models for predicting iron and nickel solubility with respect to non-stoichiometric nickel ferrites are briefly discussed showing that only one of these is likely to be credible. (author)

  11. Carbon allocation to major metabolites in illuminated leaves is not just proportional to photosynthesis when gaseous conditions (CO2 and O2 ) vary.

    Science.gov (United States)

    Abadie, Cyril; Bathellier, Camille; Tcherkez, Guillaume

    2018-04-01

    In gas-exchange experiments, manipulating CO 2 and O 2 is commonly used to change the balance between carboxylation and oxygenation. Downstream metabolism (utilization of photosynthetic and photorespiratory products) may also be affected by gaseous conditions but this is not well documented. Here, we took advantage of sunflower as a model species, which accumulates chlorogenate in addition to sugars and amino acids (glutamate, alanine, glycine and serine). We performed isotopic labelling with 13 CO 2 under different CO 2 /O 2 conditions, and determined 13 C contents to compute 13 C-allocation patterns and build-up rates. The 13 C content in major metabolites was not found to be a constant proportion of net fixed carbon but, rather, changed dramatically with CO 2 and O 2 . Alanine typically accumulated at low O 2 (hypoxic response) while photorespiratory intermediates accumulated under ambient conditions and at high photorespiration, glycerate accumulation exceeding serine and glycine build-up. Chlorogenate synthesis was relatively more important under normal conditions and at high CO 2 and its synthesis was driven by phosphoenolpyruvate de novo synthesis. These findings demonstrate that carbon allocation to metabolites other than photosynthetic end products is affected by gaseous conditions and therefore the photosynthetic yield of net nitrogen assimilation varies, being minimal at high CO 2 and maximal at high O 2 . © 2018 The Authors. New Phytologist © 2018 New Phytologist Trust.

  12. Geochemical Data for Upper Mineral Creek, Colorado, Under Existing Ambient Conditions and During an Experimental pH Modification, August 2005

    Science.gov (United States)

    Runkel, Robert L.; Kimball, Briant A.; Steiger, Judy I.; Walton-Day, Katherine

    2009-01-01

    Mineral Creek, an acid mine drainage stream in south-western Colorado, was the subject of a water-quality study that employed a paired synoptic approach. Under the paired synoptic approach, two synoptic sampling campaigns were conducted on the same study reach. The initial synoptic campaign, conducted August 22, 2005, documented stream-water quality under existing ambient conditions. A second synoptic campaign, conducted August 24, 2005, documented stream-water quality during a pH-modification experiment that elevated the pH of Mineral Creek. The experimental pH modification was designed to determine the potential reductions in dissolved constituent concentrations that would result from the implementation of an active treatment system for acid mine drainage. During both synoptic sampling campaigns, a solution containing lithium bromide was injected continuously to allow for the calculation of streamflow using the tracer-dilution method. Synoptic water-quality samples were collected from 30 stream sites and 11 inflow locations along the 2-kilometer study reach. Data from the study provide spatial profiles of pH, concentration, and streamflow under both existing and experimentally-altered conditions. This report presents the data obtained August 21-24, 2005, as well as the methods used for sample collection and data analysis.

  13. Physiological functions at single-cell level of Lactobacillus spp. isolated from traditionally fermented cabbage in response to different pH conditions.

    Science.gov (United States)

    Olszewska, Magdalena A; Kocot, Aleksandra M; Łaniewska-Trokenheim, Łucja

    2015-04-20

    Changes in pH are significant environmental stresses that may be encountered by lactobacilli during fermentation processes or passage through the gastrointestinal tract. Here, we report the cell response of Lactobacillus spp. isolated from traditionally fermented cabbage subjected to acid/alkaline treatments at pH 2.5, 7.4 and 8.1, which represented pH conditions of the gastrointestinal tract. Among six isolates, four species of Lactobacillus plantarum and two of Lactobacillus brevis were identified by fluorescence in situ hybridization (FISH). The fluorescence-based strategy of combining carboxyfluorescein diacetate (CFDA) and propidium iodine (PI) into a dual-staining assay was used together with epifluorescence microscopy (EFM) and flow cytometry (FCM) for viability assessment. The results showed that the cells maintained esterase activity and membrane integrity at pH 8.1 and 7.4. There was also no loss of culturability as shown by plate counts. In contrast, the majority of 2.5 pH-treated cells had a low extent of esterase activity, and experienced membrane perturbation. For these samples, an extensive loss of culturability was demonstrated. Comparison of the results of an in situ assessment with that of the conventional culturing method has revealed that although part of the stressed population was unable to grow on the growth media, it was deemed viable using a CFDA/PI assay. However, there was no significant change in the cell morphology among pH-treated lactobacilli populations. These analyses are expected to be useful in understanding the cell response of Lactobacillus strains to pH stress and may facilitate future investigation into functional and industrial aspects of this response. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Corrosion study of API 5L x-series pipeline steels in 3.5% NaCl solution under varying conditions

    International Nuclear Information System (INIS)

    Shahid, M.; Qureshi, M.I.; Farooq, M.U.; Khan, M.I.

    2003-01-01

    Pipelines provide convenient and efficient means for mass transportation of variety of fluids, such as oil and gas, over varying distances. In the last two decades or so, pipeline designers focused mainly on the usage of larger sizes and higher operating pressures for achieving higher transportation efficiency. This has been accomplished through the provision of steels with progressive increase in yield strength coupled with good weldability and sufficient toughness to restrict crack propagation. In addition to higher strength and toughness, developing pipeline technologies have required improved resistance to corrosion, which has been tried with specific alloy additions and special control over non-metallic inclusions. Corrosion investigations were carried out on various grades of pipeline steels (API 5L X-46, X-52, X-56, X-60 and X- 70) under varying environmental conditions. This paper describes the results pertaining to corrosion behavior of the steels in 3.5% NaCl solutions in stagnant, turbulent and deaerated conditions. It was found that all grades corrode in this solution and their corrosion potentials and corrosion currents are in close vicinity of each other. Turbulent solutions, however, have shown an increase in corrosion rates whereas deaeration has revealed a relative decrease in aggressivity of the electrolyte. (author)

  15. Electrolyte Engineering Toward Efficient Hydrogen Production Electrocatalysis with Oxygen-crossover Regulation under Densely Buffered Near-neutral pH Conditions

    KAUST Repository

    Shinagawa, Tatsuya; Takanabe, Kazuhiro

    2015-01-01

    This study tackles the core issues associated with near-neutral pH water splitting, particularly regarding electrolyte engineering in the electrocatalysis and product cross-over. We demonstrate that solute engineering has a major impact on water splitting electrocatalysis because the diffusion component, often not well integrated into performance descriptions, largely determines the overall performance. The hydrogen evolution reaction (HER) was investigated on Pt, Ni and NiMo catalysts in various concentrations of cations (Li+, K+, Na+) and anions (H2PO4−, HPO42−, PO43− and HCO3−) to describe its performance by quantifying kinetics, diffusion and solution resistance. In fact, the choice of electrolyte in terms of its identity and activity drastically altered the HER rate and oxygen mass-transport flux at near-neutral pH. Electrolyte properties (activity coefficient, kinematic viscosity and diffusion coefficient) accurately described the diffusion contribution, which can be easily isolated when a highly active Pt catalyst was used for the HER. By analyzing these properties, we maximized the HER rate on the Pt by tuning the solute concentration (typically 1.5 – 2.0 M). Moreover, the kinematic viscosity and oxygen solubility in such densely buffered conditions governed the oxygen mass-transport flux in the electrolyte, which in turn tuned the cross-over flux. At near-neutral pH, as high as 90 % selectivity toward the HER was achieved even under an oxygen saturated condition, where only a 40 mV overpotential was needed to achieve 10 mA cm−2 for the HER. This information can be regarded as an important milestone for achieving a highly efficient water splitting system at near-neutral pH.

  16. Electrolyte Engineering Toward Efficient Hydrogen Production Electrocatalysis with Oxygen-crossover Regulation under Densely Buffered Near-neutral pH Conditions

    KAUST Repository

    Shinagawa, Tatsuya

    2015-12-30

    This study tackles the core issues associated with near-neutral pH water splitting, particularly regarding electrolyte engineering in the electrocatalysis and product cross-over. We demonstrate that solute engineering has a major impact on water splitting electrocatalysis because the diffusion component, often not well integrated into performance descriptions, largely determines the overall performance. The hydrogen evolution reaction (HER) was investigated on Pt, Ni and NiMo catalysts in various concentrations of cations (Li+, K+, Na+) and anions (H2PO4−, HPO42−, PO43− and HCO3−) to describe its performance by quantifying kinetics, diffusion and solution resistance. In fact, the choice of electrolyte in terms of its identity and activity drastically altered the HER rate and oxygen mass-transport flux at near-neutral pH. Electrolyte properties (activity coefficient, kinematic viscosity and diffusion coefficient) accurately described the diffusion contribution, which can be easily isolated when a highly active Pt catalyst was used for the HER. By analyzing these properties, we maximized the HER rate on the Pt by tuning the solute concentration (typically 1.5 – 2.0 M). Moreover, the kinematic viscosity and oxygen solubility in such densely buffered conditions governed the oxygen mass-transport flux in the electrolyte, which in turn tuned the cross-over flux. At near-neutral pH, as high as 90 % selectivity toward the HER was achieved even under an oxygen saturated condition, where only a 40 mV overpotential was needed to achieve 10 mA cm−2 for the HER. This information can be regarded as an important milestone for achieving a highly efficient water splitting system at near-neutral pH.

  17. Tribological and Wear Performance of Carbide Tools with TiB2 PVD Coating under Varying Machining Conditions of TiAl6V4 Aerospace Alloy

    Directory of Open Access Journals (Sweden)

    Jose Mario Paiva

    2017-11-01

    Full Text Available Tribological phenomena and tool wear mechanisms during machining of hard-to-cut TiAl6V4 aerospace alloy have been investigated in detail. Since cutting tool wear is directly affected by tribological phenomena occurring between the surfaces of the workpiece and the cutting tool, the performance of the cutting tool is strongly associated with the conditions of the machining process. The present work shows the effect of different machining conditions on the tribological and wear performance of TiB2-coated cutting tools compared to uncoated carbide tools. FEM modeling of the temperature profile on the friction surface was performed for wet machining conditions under varying cutting parameters. Comprehensive characterization of the TiB2 coated vs. uncoated cutting tool wear performance was made using optical 3D imaging, SEM/EDX and XPS methods respectively. The results obtained were linked to the FEM modeling. The studies carried out show that during machining of the TiAl6V4 alloy, the efficiency of the TiB2 coating application for carbide cutting tools strongly depends on cutting conditions. The TiB2 coating is very efficient under roughing at low speeds (with strong buildup edge formation. In contrast, it shows similar wear performance to the uncoated tool under finishing operations at higher cutting speeds when cratering wear predominates.

  18. Automatic Traffic Data Collection under Varying Lighting and Temperature Conditions in Multimodal Environments: Thermal versus Visible Spectrum Video-Based Systems

    Directory of Open Access Journals (Sweden)

    Ting Fu

    2017-01-01

    Full Text Available Vision-based monitoring systems using visible spectrum (regular video cameras can complement or substitute conventional sensors and provide rich positional and classification data. Although new camera technologies, including thermal video sensors, may improve the performance of digital video-based sensors, their performance under various conditions has rarely been evaluated at multimodal facilities. The purpose of this research is to integrate existing computer vision methods for automated data collection and evaluate the detection, classification, and speed measurement performance of thermal video sensors under varying lighting and temperature conditions. Thermal and regular video data was collected simultaneously under different conditions across multiple sites. Although the regular video sensor narrowly outperformed the thermal sensor during daytime, the performance of the thermal sensor is significantly better for low visibility and shadow conditions, particularly for pedestrians and cyclists. Retraining the algorithm on thermal data yielded an improvement in the global accuracy of 48%. Thermal speed measurements were consistently more accurate than for the regular video at daytime and nighttime. Thermal video is insensitive to lighting interference and pavement temperature, solves issues associated with visible light cameras for traffic data collection, and offers other benefits such as privacy, insensitivity to glare, storage space, and lower processing requirements.

  19. The effect of bedload transport rates on bedform and planform morphological development in a laboratory meandering stream under varying flow conditions

    Science.gov (United States)

    Sullivan, C.; Good, R. G. R.; Binns, A. D.

    2017-12-01

    Sediment transport processes in streams provides valuable insight into the temporal evolution of planform and bedform geometry. The majority of previous experimental research in the literature has focused on bedload transport and corresponding bedform development in rectangular, confined channels, which does not consider planform adjustment processes in streams. In contrast, research conducted with laboratory streams having movable banks can investigate planform development in addition to bedform development, which is more representative of natural streams. The goal of this research is to explore the relationship between bedload transport rates and the morphological adjustments in meandering streams. To accomplish this, a series of experimental runs were conducted in a 5.6 m by 1.9 m river basin flume at the University of Guelph to analyze the bedload impacts on bed formations and planform adjustments in response to varying flow conditions. In total, three experimental runs were conducted: two runs using steady state conditions and one run using unsteady flow conditions in the form of a symmetrical hydrograph implementing quasi steady state flow. The runs were performed in a series of time-steps in order to monitor the evolution of the stream morphology and the bedload transport rates. Structure from motion (SfM) was utilized to capture the channel morphology after each time-step, and Agisoft PhotoScan software was used to produce digital elevation models to analyze the morphological evolution of the channel with time. Bedload transport rates were quantified using a sediment catch at the end of the flume. Although total flow volumes were similar for each run, the morphological evolution and bedload transport rates in each run varied. The observed bedload transport rates from the flume are compared with existing bedload transport formulas to assess their accuracy with respect to sediment transport in unconfined meandering channels. The measured sediment transport

  20. On the formation of sulphuric acid – amine clusters in varying atmospheric conditions and its influence on atmospheric new particle formation

    Directory of Open Access Journals (Sweden)

    I. K. Ortega

    2012-10-01

    Full Text Available Sulphuric acid is a key component in atmospheric new particle formation. However, sulphuric acid alone does not form stable enough clusters to initiate particle formation in atmospheric conditions. Strong bases, such as amines, have been suggested to stabilize sulphuric acid clusters and thus participate in particle formation. We modelled the formation rate of clusters with two sulphuric acid and two amine molecules (JA2B2 at varying atmospherically relevant conditions with respect to concentrations of sulphuric acid ([H2SO4], dimethylamine ([DMA] and trimethylamine ([TMA], temperature and relative humidity (RH. We also tested how the model results change if we assume that the clusters with two sulphuric acid and two amine molecules would act as seeds for heterogeneous nucleation of organic vapours (other than amines with higher atmospheric concentrations than sulphuric acid. The modelled formation rates JA2B2 were functions of sulphuric acid concentration with close to quadratic dependence, which is in good agreement with atmospheric observations of the connection between the particle formation rate and sulphuric acid concentration. The coefficients KA2B2 connecting the cluster formation rate and sulphuric acid concentrations as JA2B2=KA2B2[H2SO4]2 turned out to depend also on amine concentrations, temperature and relative humidity. We compared the modelled coefficients KA2B2 with the corresponding coefficients calculated from the atmospheric observations (Kobs from environments with varying temperatures and levels of anthropogenic influence. By taking into account the modelled behaviour of JA2B2 as a function of [H2SO4], temperature and RH, the atmospheric particle formation rate was reproduced more closely than with the traditional semi-empirical formulae based on sulphuric acid concentration only. The formation rates of clusters with two sulphuric acid and two amine molecules with different amine compositions (DMA or TMA or one of both had

  1. Reorganization of the 3D matrix of polyelectrolytes complexes of chitosan/chondroitin sulfate swollen in different conditions of pH and immersion time

    International Nuclear Information System (INIS)

    Fajardo, Andre R.; Piai, Juliana F.; Rubira, Adley F.; Muniz, Edvani C.

    2009-01-01

    The chitosan (CT), a polysaccharide that has excellent properties for use as biomaterials, shows cationic nature and properties of high charge density in acidic solutions, thus CT can form complex polyelectrolyte (PEC) with polyanionic moieties such as the chondroitin sulfate (CS), a key component of cartilage matrix. We studied the reorganization of chains on 3D matrix of CT/CS PEC at swollen state in different conditions of pH and immersion time. It was verified that this PEC (QT/CS) has the capacity to reorganize its 3D matrix but it depends of the pH of the medium in which it is swelled and the time that remains immersed. The reorganization of the 3D matrix is caused by the reordering of the chains forming the PEC after the release of the CS, that occurs mainly at pH values higher than or close to the pKa of CT (pKa CT) . Such reorganization was detected by X-ray diffraction profiles and allows an increase in crystallinity, thermal stability and pore size of the PEC. This shows that the PEC produced can be processed to suit its use as bio material, applied i.e. as drugs release devices. (author)

  2. Reorganization of the 3D matrix of polyelectrolytes complexes of chitosan/chondroitin sulfate swollen in different conditions of pH and immersion time

    Energy Technology Data Exchange (ETDEWEB)

    Fajardo, Andre R.; Piai, Juliana F.; Rubira, Adley F.; Muniz, Edvani C., E-mail: ecmuniz@uem.b [Universidade Estadual de Maringa (DG/UEM), PR (Brazil). Dept. de Quimica. Grupo de Materiais Polimericos e Compositos

    2009-07-01

    The chitosan (CT), a polysaccharide that has excellent properties for use as biomaterials, shows cationic nature and properties of high charge density in acidic solutions, thus CT can form complex polyelectrolyte (PEC) with polyanionic moieties such as the chondroitin sulfate (CS), a key component of cartilage matrix. We studied the reorganization of chains on 3D matrix of CT/CS PEC at swollen state in different conditions of pH and immersion time. It was verified that this PEC (QT/CS) has the capacity to reorganize its 3D matrix but it depends of the pH of the medium in which it is swelled and the time that remains immersed. The reorganization of the 3D matrix is caused by the reordering of the chains forming the PEC after the release of the CS, that occurs mainly at pH values higher than or close to the pKa of CT (pKa CT) . Such reorganization was detected by X-ray diffraction profiles and allows an increase in crystallinity, thermal stability and pore size of the PEC. This shows that the PEC produced can be processed to suit its use as bio material, applied i.e. as drugs release devices. (author)

  3. Assessment of GFP fluorescence in cells of Streptococcus gordonii under conditions of low pH and low oxygen concentration

    DEFF Research Database (Denmark)

    Hansen, M.C.; Palmer, R.J.; Udsen, C.

    2001-01-01

    (obtained by addition of L-cysteine as reducing agent). When an anaerobically grown (nonfluorescent) >50 mum thick biofilm was shifted to aerobic conditions, fluorescence could be detected within 4 min, reaching a maximum over the next 16 min. It was not possible to detect any fluorescence gradients...

  4. Reconstruction of Oryza sativa indica Genome Scale Metabolic Model and Its Responses to Varying RuBisCO Activity, Light Intensity, and Enzymatic Cost Conditions

    Directory of Open Access Journals (Sweden)

    Ankita Chatterjee

    2017-11-01

    Full Text Available To combat decrease in rice productivity under different stresses, an understanding of rice metabolism is needed. Though there are different genome scale metabolic models (GSMs of Oryza sativa japonica, no GSM with gene-protein-reaction association exist for Oryza sativa indica. Here, we report a GSM, OSI1136 of O.s. indica, which includes 3602 genes and 1136 metabolic reactions and transporters distributed across the cytosol, mitochondrion, peroxisome, and chloroplast compartments. Flux balance analysis of the model showed that for varying RuBisCO activity (Vc/Vo (i the activity of the chloroplastic malate valve increases to transport reducing equivalents out of the chloroplast under increased photorespiratory conditions and (ii glyceraldehyde-3-phosphate dehydrogenase and phosphoglycerate kinase can act as source of cytosolic ATP under decreased photorespiration. Under increasing light conditions we observed metabolic flexibility, involving photorespiration, chloroplastic triose phosphate and the dicarboxylate transporters of the chloroplast and mitochondrion for redox and ATP exchanges across the intracellular compartments. Simulations under different enzymatic cost conditions revealed (i participation of peroxisomal glutathione-ascorbate cycle in photorespiratory H2O2 metabolism (ii different modes of the chloroplastic triose phosphate transporters and malate valve, and (iii two possible modes of chloroplastic Glu–Gln transporter which were related with the activity of chloroplastic and cytosolic isoforms of glutamine synthetase. Altogether, our results provide new insights into plant metabolism.

  5. Differences in nutrient uptake capacity of the benthic filamentous algae Cladophora sp., Klebsormidium sp. and Pseudanabaena sp. under varying N/P conditions.

    Science.gov (United States)

    Liu, Junzhuo; Vyverman, Wim

    2015-03-01

    The N/P ratio of wastewater can vary greatly and directly affect algal growth and nutrient removal process. Three benthic filamentous algae species Cladophora sp., Klebsormidium sp. and Pseudanabaena sp. were isolated from a periphyton bioreactor and cultured under laboratory conditions on varying N/P ratios to determine their ability to remove nitrate and phosphorus. The N/P ratio significantly influenced the algal growth and phosphorus uptake process. Appropriate N/P ratios for nitrogen and phosphorus removal were 5-15, 7-10 and 7-20 for Cladophora sp., Klebsormidium sp. and Pseudanabaena sp., respectively. Within these respective ranges, Cladophora sp. had the highest biomass production, while Pseudanabaena sp. had the highest nitrogen and phosphorus contents. This study indicated that Cladophora sp. had a high capacity of removing phosphorus from wastewaters of low N/P ratio, and Pseudanabaena sp. was highly suitable for removing nitrogen from wastewaters with high N/P ratio. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Phosphorus sorption-desorption and effects of temperature, pH and salinity on phosphorus sorption in marsh soils from coastal wetlands with different flooding conditions.

    Science.gov (United States)

    Bai, Junhong; Ye, Xiaofei; Jia, Jia; Zhang, Guangliang; Zhao, Qingqing; Cui, Baoshan; Liu, Xinhui

    2017-12-01

    Wetland soils act as a sink or source of phosphorus (P) to the overlaying water due to phosphorus sorption-desorption processes. Litter information is available on sorption and desorption behaviors of phosphorus in coastal wetlands with different flooding conditions. Laboratory experiments were conducted to investigate phosphorus sorption-desorption processes, fractions of adsorbed phosphorus, and the effects of salinity, pH and temperature on phosphorus sorption on soils in tidal-flooding wetlands (TW), freshwater-flooding wetlands (FW) and seasonal-flooding wetlands (SW) in the Yellow River Delta. Our results showed that the freshly adsorbed phosphorus dominantly exists in Occluded-P and Fe/AlP and their percentages increased with increasing phosphorus adsorbed. Phosphorus sorption isotherms could be better described by the modified Langmuir model than by the modified Freundlich model. A binomial equation could be properly used to describe the effects of salinity, pH, and temperature on phosphorus sorption. Phosphorus sorption generally increased with increasing salinity, pH, and temperature at lower ranges, while decreased in excess of some threshold values. The maximum phosphorus sorption capacity (Q max ) was larger for FW soils (256 mg/kg) compared with TW (218 mg/kg) and SW soils (235 mg/kg) (p < 0.05). The percentage of phosphorus desorption (P des ) in the FW soils (7.5-63.5%) was much lower than those in TW (27.7-124.9%) and SW soils (19.2-108.5%). The initial soil organic matter, pH and the exchangeable Al, Fe and Cd contents were important factors influencing P sorption and desorption. The findings of this study indicate that freshwater restoration can contribute to controlling the eutrophication status of water bodies through increasing P sorption. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Influence of pH and media composition on suspension stability of silver, zinc oxide, and titanium dioxide nanoparticles and immobilization of Daphnia magna under guideline testing conditions.

    Science.gov (United States)

    Cupi, Denisa; Hartmann, Nanna B; Baun, Anders

    2016-05-01

    In aquatic toxicity testing of engineered nanoparticles (ENPs) the process of agglomeration is very important as it may alter bioavailability and toxicity. In the present study, we aimed to identify test conditions that are favorable for maintaining stable ENP suspensions. We evaluated the influence of key environmental parameters: pH (2-12) and ionic strength using M7, Soft EPA (S EPA) medium, and Very Soft EPA (VS EPA) medium; and observed the influence of these parameters on zeta potential, zeta average, and acute immobilization of Daphnia magna for three different ENPs. Despite being sterically stabilized, test suspensions of silver (Ag) ENPs formed large agglomerates in both VS EPA and M7 media; and toxicity was found to be higher in VS EPA medium due to increased dissolution. Low-agglomerate suspensions for zinc oxide (ZnO) could be obtained at pH 7 in VS EPA medium, but the increase in dissolution caused higher toxicity than in M7 medium. Titanium dioxide (TiO2) ENPs had a point of zero charge in the range of pH 7-8. At pH 7 in VS EPA, agglomerates with smaller hydrodynamic diameters (~200nm) were present compared to the high ionic strength M7 medium where hydrodynamic diameters reached micrometer range. The stable suspensions of TiO2 ENPs caused immobilization of D. magna, 48-h EC50 value of 13.7mgL(-1) (95% CI, 2.4mg-79.1mgL(-1)); whereas no toxicity was seen in the unstable, highly agglomerated M7 medium suspensions, 48-h EC50 >100mgL(-1). The current study provides a preliminary approach for methodology in testing and assessing stability and toxicity of ENPs in aquatic toxicity tests of regulatory relevance. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. Seed banks as a source of vegetation regeneration to support the recovery of degraded rivers: A comparison of river reaches of varying condition.

    Science.gov (United States)

    O'Donnell, Jessica; Fryirs, Kirstie A; Leishman, Michelle R

    2016-01-15

    Anthropogenic disturbance has contributed to widespread geomorphic adjustment and the degradation of many rivers. This research compares for river reaches of varying condition, the potential for seed banks to support geomorphic river recovery through vegetation regeneration. Seven river reaches in the lower Hunter catchment of south-eastern Australia were assessed as being in poor, moderate, or good condition, based on geomorphic and ecological indicators. Seed bank composition within the channel and floodplain (determined in a seedling emergence study) was compared to standing vegetation. Seed bank potential for supporting geomorphic recovery was assessed by measuring native species richness, and the abundance of different plant growth forms, with consideration of the roles played by different growth forms in geomorphic adjustment. The exotic seed bank was considered a limiting factor for achieving ecological restoration goals, and similarly analysed. Seed bank native species richness was comparable between the reaches, and regardless of condition, early successional and pioneer herbs, sedges, grasses and rushes dominated the seed bank. The capacity for these growth forms to colonise and stabilise non-cohesive sediments and initiate biogeomorphic succession, indicates high potential for the seed banks of even highly degraded reaches to contribute to geomorphic river recovery. However, exotic propagules increasingly dominated the seed banks of moderate and poor condition reaches and reflected increasing encroachment by terrestrial exotic vegetation associated with riparian degradation. As the degree of riparian degradation increases, the resources required to control the regeneration of exotic species will similarly increase, if seed bank-based regeneration is to contribute to both geomorphic and ecological restoration goals. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. New Insight into the Hydrogen Evolution Reaction under Buffered Near-Neutral pH Conditions: Enthalpy and Entropy of Activation

    KAUST Repository

    Shinagawa, Tatsuya

    2016-10-06

    Electrochemical conversion of thermodynamically stable chemicals of water and carbon dioxide is regarded as a core technology for achieving sustainability in our society. In both cases, the electrochemical hydrogen evolution reaction (HER) is a key reaction, particularly at near-neutral pH. This study addresses the kinetic aspects of the HER in buffered near-neutral pH conditions using a variety of electrode materials (W, Ni, Pt, Au, and Cu) over a wide temperature range (299–346 K). When the overall performance was summarized with respect to the binding energy of the reaction intermediate species, a classic volcano-shaped relationship was obtained. Interestingly, the temperature sensitivity analysis disclosed that smaller activation energies did not always lead to higher performance in 1.5 mol L–1 K-phosphate solution (pH 5.8). Detailed analysis of the temperature- and potential-dependent parameters revealed that smaller activation energies coincided with smaller values of the pre-exponential factor in the Arrhenius’ equation (associated with the entropy of activation). Due to the trade-off relationship of enthalpy–entropy compensation in the current system, the conventional approach of mixing elements of lower and higher binding energies to the intermediate species failed: even though Ni–Cu showed lower apparent activation energy, its activity toward the HER was between that of Ni and Cu due to the lowered entropy of activation. This study demonstrates the unrevealed fundamental aspects of the HER in buffered near-neutral condition, which contributes to the rational development of efficient energy and material conversion systems.

  10. Persistent and non-persistent strains of Listeria monocytogenes: A focus on growth kinetics under different temperature, salt, and pH conditions and their sensitivity to sanitizers.

    Science.gov (United States)

    Magalhães, R; Ferreira, V; Brandão, T R S; Palencia, R Casquete; Almeida, G; Teixeira, P

    2016-08-01

    This study aimed to investigate the effect of different conditions, including temperature (37 °C, 22 °C, and 4 °C), NaCl concentrations (2.5%, 4%, and 8%), and acidity (pH = 5), on the growth response of persistent and non-persistent isolates of Listeria monocytogenes. The resistance to two common sanitizers (benzalkonium chloride and hydrogen peroxide) was also investigated. A selected group of 41 persistent and non-persistent L. monocytogenes isolates recovered from three cheese processing plants during a previous longitudinal study was assembled. Average lag time was similar for persistent and non-persistent isolates grown at 37 °C, 22 °C and 4 °C but significantly shorter (p < 0.05) for persistent isolates grown at 2.5%, 4% and 8% NaCl, and at pH 5. Average growth rates were significantly higher (p < 0.05) for persistent than for non-persistent isolates when grown at 22 °C, 2.5%, 4% and 8% NaCl, and at pH 5. These results suggest that persistent strains may be better adapted to grow under stressful conditions frequently encountered in food processing environments than non-persistent strains. No relation between persistence and resistance to the tested sanitizers was found. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. A method comparison of total and HMW adiponectin: HMW/total adiponectin ratio varies versus total adiponectin, independent of clinical condition.

    Science.gov (United States)

    van Andel, Merel; Drent, Madeleine L; van Herwaarden, Antonius E; Ackermans, Mariëtte T; Heijboer, Annemieke C

    2017-02-01

    Total and high-molecular-weight (HMW) adiponectin have been associated with endocrine and cardiovascular pathology. As no gold standard is available, the discussion about biological relevance of isoforms is complicated. In our study we perform a method comparison between two commercially available assays measuring HMW and total adiponectin, in various patient groups, thus contributing further to this discussion. We determined levels of HMW and total adiponectin using assays by Lumipulse® and Millipore® respectively, in 126 patients with different clinical characteristics (n=29 healthy volunteers, n=22 dialysis patients, n=25 elderly with body mass index (BMI) LUMIPULSE ∗0.5-0.9=total adiponectin MILLIPORE , albeit with significant deviation from linearity (p<0.001). Pearson's correlation was R=0.987 (p=0.000). No significant differences between patient groups were observed (p=0.190). The HMW/total adiponectin ratio varies with total adiponectin concentration independent of clinical conditions studied. Our results imply that total and HMW adiponectin have similar utility when assessing adiponectin levels in blood, as the ratio is independent of clinical condition. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Effects of Varying RedoxConditions on Natural Attenuation of Inorganic Contaminants from the D-Area Coal Pile Runoff Basin (U)

    Energy Technology Data Exchange (ETDEWEB)

    Kaplan, D

    2004-05-30

    The objective of this study was to provide geochemical parameters to characterize the D-Area Coal Pile Runoff Basin (DCPRB) sediment as a potential source term. It is anticipated that the measured values will be used in risk calculations and will provide additional technical support for imposing Monitored Natural Attenuation at D-Area. This study provides a detailed evaluation of the DCPRB sediment and is part of another study that quantified the Monitored Natural Attenuation of inorganic contaminants more broadly at the D-Area Expanded Operable Unit, which includes the DCPRB (Powell et al. 2004). Distribution coefficients (K{sub d} values; a solid to liquid contaminant concentration ratio) and the Potentially Leachable Fraction (the percent of the total contaminant concentration in the sediment that can likely contribute to a contaminant plume) were measured in a DCPRB sediment as a function of redox conditions. Redox conditions at the DCPRB are expected to vary greatly as the system undergoes varying drying and flooding conditions. Conservative values; K{sub d} values that err on the side of being too low and Potentially Leachable Fraction values that err on the side of being too high, are presented. The K{sub d} values are high compared to conservative literature values, and underscores the importance of measuring site-specific values to provide estimates of sediments natural attenuation/sorption capacities. The Potentially Leachable Fraction indicates that as little as 27% of the As, but all of the Cu and Tl will be part of the source term. In the case of the As, the remaining 83% will likely never leach out of the sediment, thereby providing a form of natural attenuation. Importantly, Be, Cr, Cu, Ni, and V concentrations in the sediment were less-than twice background levels, indicating this sediment was not a potential source for these contaminants. K{sub d} values generally increased significantly (As, Cd, Co, Cr, Cu, Ni, Se, and Tl) when the sediment was

  13. Release of copper from sintered tungsten-bronze shot under different pH conditions and its potential toxicity to aquatic organisms

    International Nuclear Information System (INIS)

    Thomas, Vernon G.; Santore, Robert C.; McGill, Ian

    2007-01-01

    Sintered tungsten-bronze is a new substitute for lead shot, and is about to be deposited in and around the wetlands of North America. This material contains copper in the alloyed form of bronze. This in vitro study was performed according to U.S. Fish and Wildlife Service criteria to determine the dissolution rate of copper from the shot, and to assess the toxic risk that it may present to aquatic organisms. The dissolution of copper from tungsten-bronze shot, pure copper shot, and glass beads was measured in a buffered, moderately hard, synthetic water of pH 5.5, 6.6, and 7.8 over a 28-day period. The dissolution of copper from both the control copper shot and the tungsten-bronze shot was affected significantly by the pH of the water and the duration of dissolution (all p values < 0.000). The rate of copper release from tungsten bronze shot was 30 to 50 times lower than that from the copper shot, depending on pH (p < 0.0000). The observed expected environmental concentration of copper released from tungsten-bronze shot after 28 days was 0.02 μg/L at pH 7.8, and 0.4 μg/L at pH 5.6, using a loading and exposure scenario specific in a U.S. Fish and Wildlife Service protocol. Ratio Quotient values derived from the highest EEC observed in this study (0.4 μg/L), and the copper toxic effect levels for all aquatic species listed in the U.S. Environmental Protection Agency ambient water quality criteria database, were all far less than the 0.1 criterion value. Given the conditions stipulated by the U.S. Fish and Wildlife Service and the U.S. Environmental Protection Agency, heavy loading from discharged tungsten-bronze shot would not pose a toxic risk to potable water, or to soil. Consequently, it would appear that no toxic risks to aquatic organisms will attend the use of tungsten-bronze shot of the approved composition. Given the likelihood that sintered tungsten-bronze of the same formula will be used for fishing weights, bullets, and wheel balance weights, it is

  14. Survival of lactic acid and chlorine dioxide treated Campylobacter jejuni under suboptimal conditions of pH, temperature and modified atmosphere

    DEFF Research Database (Denmark)

    Smigic, Nada; Rajkovic, Andreja; Nielsen, Dennis Sandris

    2010-01-01

    As mild decontamination treatments are gaining more and more interest due to increased consumer demands for fresh foods, it is of great importance to establish the influence of decontamination treatments on the subsequent bacterial behaviour under suboptimal storage conditions. For this purpose...... Campylobacter jejuni cells treated with lactic acid (LA, 3% lactic acid, pH 4.0, 2 min) or chlorine dioxide (ClO(2), 20 ppm, 2 min) were inoculated in Bolton broth (pH 6.0) and incubated under 80% O(2)/20% N(2), 80% CO(2)/20% N(2), air or micro-aerophilic (10% CO(2)/85% N(2)/5% O(2)) atmosphere, at 4 degrees C...... on their pH(i) values. The pH(i) response was independent on the surrounding atmosphere since similar distribution of the subpopulations was observed for all tested atmospheres. However, the pH(i) response was dependent on the initial decontamination treatment. The investigation of intracellular parameters...

  15. Effects of Organic Load, pH, and EC Variations of Raw Wastewater and Weather Condition on the Efficiency of Yazd Stabilization Ponds

    Directory of Open Access Journals (Sweden)

    Seyed Alireza Mozaheb

    2009-06-01

    Full Text Available This study investigates the effects of organic load, pH, and EC variations of raw wastewater as well as the effect of weather condition on organic removal in Yazd wastewater Stabilization Ponds (2007. During the course of this study, composite samples were collected from the inlet and outlet of the anaerobic pond and the final effluent to measure such quality parameters as BOD5, COD, TSS, EC, and pH.  BOD5, COD, TSS, and Fecal coliform removal efficiencies in the final effluent were found to be 64.9%, 44.9 %, 62.6 %, and 99.96%, respectively. No intestinal nematode egg was observed. Comparison of BOD5 and COD concentrations in the filtered and non-filtered samples showed that 52% of the BOD5 and 57% of the COD in the final effluent, respectively, were due to the presence of algal mass and organic suspended solids in the non-filtered samples. The results showed that variations in organic load, pH, EC as well as seasonal weather variations had no effects on organic removal and that the removal of BOD5 was almost constant. Effluent EC was higher than influent EC. This phenomenon can be related to the evaporation rate in wastewater stabilization ponds. The survey of algae in the final effluent showed that the major species of algae were Phytoconis, Chlorella, and Anabaena.

  16. In vitro, ex vivo and in vivo examination of buccal absorption of metoprolol with varying pH in TR146 cell culture, porcine buccal mucosa and Göttingen minipigs

    DEFF Research Database (Denmark)

    Holm, René; Meng-Lund, Emil; Andersen, Morten B.

    2013-01-01

    This work studied the buccal absorption of metoprolol in vitro, ex vivo and in vivo as a function of buffered pH at 7.4, 8.5, 9.0 and 9.5. Permeability studies showed a correlation (r(2)=0.92) between in vitro TR146 cell culture and ex vivo porcine buccal mucosa in a modified Ussing chamber...... was obtained after buccal dosing (58-107%) compared to oral (3%) administration, ranging 58-107% and 3%, respectively. Macroscopically, no local toxic effects were observed by visual inspection of mini-pig cheeks. A very clear level C in vitro in vivo correlation (r(2)=0.98) was obtained between the observed....... A higher apparent permeability was observed at higher pH values, i.e. the more compound that was unionised the higher the permeability. In vivo studies were conducted in anaesthetised Göttingen mini-pigs. A clear influence of pH on the absorption was seen and a significant higher absolute bioavailability...

  17. Variability of the morphometric features of Calliphora vicina (Diptera, Calliphoridae under the varying and constant micro-climatic condi-tions

    Directory of Open Access Journals (Sweden)

    L. I. Faly

    2013-03-01

    Full Text Available Variability of the main morphometric features of imago flies Calliphora vicina R.-D. (Diptera, Calliphoridae of two samples was studied. First sample consists of individuals caught in the wild (park ecosystems of Dnipropetrovsk, the second one – specimens cultured in the laboratory under the constant temperature and humidity. Possible using of C. vicina R.-D. as a bioindicator of anthropogenic factors is analysed. Environmental factors may act as the stimulators of adaptive changes in physiological functions, as the constraints that cause impossibility of the existence of certain species in particular conditions, and as modifiers that determine the morpho- anatomical and physiological changes in organisms. The most significant differences between studied samples were found for the width (“laboratory” individuals are characterized by larger head size and for the length of limbs segments. The fluctuating range of the head width in specimens collected in the wild is much wider, due to the heterogeneity of the micro-climatic conditions of the larvae development and trophic resources. Maximal negative asymmetry of the head width is observed in individuals C. vicina R.-D. of the “natural” sample as compared with “laboratory” individuals. Among imagoes caught in the wild the individuals with a relatively wide head are dominated, as evidenced by the large positive value of kurtosis. At the same time, the distribution of values in “laboratory” individuals is almost normal. In adults bred in the laboratory the shortening of segments of the leg pair I is observed in comparison with the individuals of “natural” sample. Similar results were recorded for other insect groups cultivated in a laboratory. For most other linear measurements of the C. vicina R.-D. body the differences between samples are not registered. Ephemeral existence of the substrate of blow flies leads to higher prevailing evolutionary adaptation of species to varying

  18. Conservadorismo condicional: estudo a partir de variáveis econômicas Conditional conservatism: a study based on economic variables

    Directory of Open Access Journals (Sweden)

    Rafael de Lacerda Moreira

    2010-12-01

    Full Text Available A Contabilidade, na perspectiva da abordagem da informação, volta-se à utilidade da informação. O Conservadorismo Condicional está ligado à tendência de a Contabilidade exigir um maior grau de verificação das boas notícias para reconhecê-las no resultado em relação ao grau de verificação das más notícias. Em face das preocupações referentes à qualidade da informação contábil, o objetivo deste artigo consiste em analisar o reflexo do Conservadorismo Condicional no resultado contábil a partir de variáveis econômicas. O estudo utiliza o Modelo Reverso de Lucros Associados a Retornos (BASU, 1997 e o modelo proposto por Kahn e Watts (2009, que analisam a relação entre as variáveis lucro contábil e retorno econômico, utilizando os valores dos retornos positivos e negativos como proxy de boas e más notícias, e outras variáveis largamente aceitas na avaliação do conservadorismo. Para tanto, foram estimados os modelos estatísticos para uma amostra de 96 empresas para o período de 2005 a 2007 partindo de informações anuais disponíveis no Economática® e dados reportados em notas explicativas. Com o objetivo de selecionar um evento econômico que pode impactar no reconhecimento assimétrico do resultado econômico, decidiu-se comparar os resultados entre empresas listadas nos níveis de governança da Bovespa com as demais empresas. Os resultados obtidos confirmam a hipótese de utilização de conservadorismo condicional na mensuração do resultado das companhias da amostra. A diferenciação positiva quanto ao grau de conservadorismo para as empresas que aderiram aos níveis de governança não são conclusivas, visto que os modelos apresentaram resultados dispersos. As variáveis econômicas criam vantagens quando as más notícias não podem ser tão claramente visíveis nas Demonstrações Contábeis, podendo diminuir os resultados futuros esperados.Accounting from an information perspective looks at the

  19. PH sensor

    OpenAIRE

    Artero, C.; Nogueras Cervera, Marc; Manuel Lázaro, Antonio

    2012-01-01

    This paper presents a design of a marine instrument for the measurement of pH in seawater. The measurement system consists of a pH electrode connected to the underwater observatory OBSEA. The extracted data are useful for scientists researching ocean acidification. Peer Reviewed

  20. Evaluation of biochar-ultrafiltration membrane processes for humic acid removal under various hydrodynamic, pH, ionic strength, and pressure conditions.

    Science.gov (United States)

    Shankar, Vaibhavi; Heo, Jiyong; Al-Hamadani, Yasir A J; Park, Chang Min; Chu, Kyoung Hoon; Yoon, Yeomin

    2017-07-15

    The performance of an ultrafiltration (UF)-biochar process was evaluated in comparison with a UF membrane process for the removal of humic acid (HA). Bench-scale UF experiments were conducted to study the rejection and flux trends under various hydrodynamic, pH, ionic strength, and pressure conditions. The resistance-in-series model was used to evaluate the processes and it showed that unlike stirred conditions, where low fouling resistance was observed (28.7 × 10 12  m -1 to 32.5 × 10 12  m -1 ), higher values and comparable trends were obtained for UF-biochar and UF alone for unstirred conditions (28.7 × 10 12  m -1 to 32.5 × 10 12  m -1 ). Thus, the processes were further evaluated under unstirred conditions. Additionally, total fouling resistance was decreased in the presence of biochar by 6%, indicating that HA adsorption by biochar could diminish adsorption fouling on the UF membrane and thus improve the efficiency of the UF-biochar process. The rejection trends of UF-biochar and UF alone were similar in most cases, whereas UF-biochar showed a noticeable increase in flux of around 18-25% under various experimental conditions due to reduced membrane fouling. Three-cycle filtration tests further demonstrated that UF-biochar showed better membrane recovery and antifouling capability by showing more HA rejection (3-5%) than UF membrane alone with each subsequent cycle of filtration. As a result of these findings, the UF-biochar process may potentially prove be a viable treatment option for the removal of HA from water. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Successful transportation of human corneal endothelial tissues without cool preservation in varying Indian tropical climatic conditions and in vitro cell expansion using a novel polymer.

    Science.gov (United States)

    Rao, Srinivas K; Sudhakar, John; Parikumar, Periyasamy; Natarajan, Sundaram; Insaan, Aditya; Yoshioka, Hiroshi; Mori, Yuichi; Tsukahara, Shigeo; Baskar, Subramani; Manjunath, Sadananda Rao; Senthilkumar, Rajappa; Thamaraikannan, Paramasivam; Srinivasan, Thangavelu; Preethy, Senthilkumar; Abraham, Samuel J K

    2014-02-01

    Though the transplantation of human corneal endothelial tissue (CET) separated from cadaver cornea is in practice, its transportation has not been reported. We report the successful transportation of CET in varying Indian climatic conditions without cool preservation and the in vitro expansion of Human Corneal Endothelial Precursor Cells (HCEPCs) using a novel Thermo-reversible gelation polymer (TGP). CET from cadaver corneas (n = 67), unsuitable for transplantation, were used. In phase I, CET was transported in Basal Culture Medium (Group I) and TGP (Group II) and in Phase II, in TGP cocktail alone, from three hospitals 250-2500 km away, to a central laboratory. The transportation time ranged from 6 h to 72 h and the outdoor temperature between 20°C and 41°C. On arrival, CET were processed, cells were expanded upto 30 days in basal culture medium (Group A) and TGP scaffold (Group B). Cell viability and morphology were documented and Reverse transcription polymerase chain reaction (RT-PCR) characterization undertaken. In Phase I, TGP yielded more viable cells (0.11 × 10(6) cells) than Group I (0.04 × 10(6) cells). In Phase II, the average cell count was 5.44 × 10(4) cells. During expansion, viability of HCEPCs spheres in TGP was maintained for a longer duration. The cells from both the groups tested positive for B-3 tubulin and negative for cytokeratins K3 and K12, thereby proving them to be HCEPCs. TGP preserves the CET during transportation without cool preservation and supports in vitro expansion, with a higher yield of HCEPCs, similar to that reported in clinical studies.

  2. Successful transportation of human corneal endothelial tissues without cool preservation in varying Indian tropical climatic conditions and in vitro cell expansion using a novel polymer

    Directory of Open Access Journals (Sweden)

    Srinivas K Rao

    2014-01-01

    Full Text Available Background: Though the transplantation of human corneal endothelial tissue (CET separated from cadaver cornea is in practice, its transportation has not been reported. We report the successful transportation of CET in varying Indian climatic conditions without cool preservation and the in vitro expansion of Human Corneal Endothelial Precursor Cells (HCEPCs using a novel Thermo-reversible gelation polymer (TGP. Materials and Methods: CET from cadaver corneas (n = 67, unsuitable for transplantation, were used. In phase I, CET was transported in Basal Culture Medium (Group I and TGP (Group II and in Phase II, in TGP cocktail alone, from three hospitals 250-2500 km away, to a central laboratory. The transportation time ranged from 6 h to 72 h and the outdoor temperature between 20°C and 41°C. On arrival, CET were processed, cells were expanded upto 30 days in basal culture medium (Group A and TGP scaffold (Group B. Cell viability and morphology were documented and Reverse transcription polymerase chain reaction (RT-PCR characterization undertaken. Results: In Phase I, TGP yielded more viable cells (0.11 × 10 6 cells than Group I (0.04 × 10 6 cells. In Phase II, the average cell count was 5.44 × 10 4 cells. During expansion, viability of HCEPCs spheres in TGP was maintained for a longer duration. The cells from both the groups tested positive for B-3 tubulin and negative for cytokeratins K3 and K12, thereby proving them to be HCEPCs. Conclusion: TGP preserves the CET during transportation without cool preservation and supports in vitro expansion, with a higher yield of HCEPCs, similar to that reported in clinical studies.

  3. Effect of Fe, Ni, and Cr on the corrosion behaviour of hyper-eutectic Al-Si automotive alloy under different pH conditions

    Directory of Open Access Journals (Sweden)

    Mohammad Salim Kaiser

    2018-05-01

    Full Text Available Effect of Fe, Ni and Cr on the corrosion behaviour of hyper-eutectic Al-Si automotive alloy was studied. The test of corrosion behaviour at different environmental pH 1, 3, 5, 7, 9, 11 and 13 was performed using conventional gravimetric measurements and complemented by resistivity, optical micrograph, scanning electron microscopy (SEM and X-ray analyser (EDX investigations. The highest corrosion rate was observed at pH 13 followed by pH 1, while in the pH range of 3.0 to 11, there is a high protection of surface due to formation of stable surface oxide film. The highest corrosion rate at pH 13 is due to presence of sodium hydroxide in the solution in which the surface oxide film is soluble. At pH 1, however, high corrosion rate can be attributed to dissolution of Al due to the surface attack by aggressive chloride ions. Presence of Fe, Ni and Cr in hyper-eutectic Al-Si automotive alloy has significant effect on the corrosion rate at both environmental pH values. Resistivity of alloy surfaces initially decreases at pH 1 and pH 13 due to formation of thin films. The SEM images of corroded samples immersed in pH 1 solution clearly show pores due to uniform degradation of the alloy. In pH 13 solution, however, the corrosion layer looks more packed and impermeable.

  4. Temperature and pH conditions for mycelial growth of Agaricus brasiliensis on axenic cultivation/ Condições de temperatura e pH para o crescimento micelial de Agaricus brasiliensis em cultivo axênico

    Directory of Open Access Journals (Sweden)

    Luzia Doretto Paccola-Meirelles

    2008-08-01

    Full Text Available Few studies have been done to determine Agaricus brasiliensis Wasser et al. (A. blazei; A. subrufescens basic mycelial growth characteristics on axenic cultivation. This study aimed to determine the optimal temperature and initial pH for mycelial growth of A. brasiliensis on malt extract agar medium to develop axenic cultivation techniques. Studied initial pH values for mycelial growth were adjusted to 3.0, 4.0, 5.0, 5.5, with HCl, 6.0, 7.0, 8.0, with NaOH, and again 7.0 and 8.0, with CaCO3. Studied temperatures for mycelial growth were 22 ºC, 25 ºC, 28 ºC, 31 ºC and 34 ºC. It was concluded that A. brasiliensis can grow in axenic cultivation at temperature range from 22 oC to 34 ºC, with optimal temperature range from 28 oC to 31 ºC and optimal temperature value of 30.5 ºC ± 0.3 ºC. It also grows in initial pH range from 4.0 to 7.0, adjusted with HCl or NaOH but not CaCO3, with optimal initial pH range from 5.5 to 6.0 and optimal initial pH value of 5.56 ± 0.05. Mycelial growth is inhibited with pH of 3.0 or lower, 8.0 or higher, or when CaCO3 is used to adjust pH in the substratum to 7.0 or higher.Poucos estudos foram desenvolvidos para determinar as condições básicas de crescimento micelial do fungo Agaricus brasiliensis Wasser et al. (A. blazei, A. subrufescens. O objetivo deste trabalho foi determinar a faixa ótima de temperatura e pH para o crescimento micelial, em agar-extrato-de-malte, de A. brasiliensis, visando o desenvolvimento de técnicas de cultivo axênica. Os valores de pH estudados foram 3,0, 4,0, 5,0 e 5,5, ajustados com HCl, 6,0, 7,0 e 8,0, ajustados com NaOH, e 7,0 e 8,0, ajustados com CaCO3. As temperaturas de crescimento estudadas foram 22 ºC; 25 ºC; 28 ºC; 31 ºC e 34 oC. Concluiu-se que A. brasiliensis cresce em uma faixa de temperatura ótima de 28 oC a 31 ºC, com valor ótimo de temperatura de 30,5 ºC ± 0,3 ºC. A faixa de pH inicial ótimo no substrato é de 5,5 a 6,0 e o valor de pH inicial

  5. Carbon steel corrosion under anaerobic-aerobic cycling conditions in near-neutral pH saline solutions - Part 1: Long term corrosion behaviour

    International Nuclear Information System (INIS)

    Sherar, B.W.A.; Keech, P.G.; Shoesmith, D.W.

    2011-01-01

    Highlights: → Anaerobic-aerobic cycling on pipeline steel forms two distinct surface morphologies. → Seventy-five percentage of the surface was covered by a black, compact layer ∼4.5 μm thick. → A tubercle, ∼3 to 4 mm in cross section, covered the remaining 25% of surface. → The tubercle cross section showed a single large pit ∼275 μm deep. - Abstract: The influence of anaerobic-aerobic cycling on pipeline steel corrosion was investigated in near-neutral carbonate/sulphate/chloride solution (pH 9) over 238 days. The corrosion rate increased and decreased as exposure conditions were switched between redox conditions. Two distinct corrosion morphologies were observed. The majority of the surface corroded uniformly to produce a black magnetite/maghemite layer approximately 4.5 μm thick. The remaining surface was covered with an orange tubercle, approximately 3-4 mm in cross section. Analysis of the tubercle cross section revealed a single large pit approximately 275 μm deep. Repeated anaerobic-aerobic cycling localized the corrosion process within this tubercle-covered pit.

  6. Comparative estimation of inevitable endogenous ileal flow of amino acids in Pekin ducks under varying dietary or physiological conditions and their significance to nutritional requirements for amino acids.

    Science.gov (United States)

    Akinde, D O

    2017-10-01

    In 2 experiments in Pekin ducks the inevitable endogenous ileal flow (IEIF) of AA was estimated at changing intake and source of crude fiber (CF) or soybean oil (SO) level. Also the roles of dry matter intake (DMI) and BW or age as well as the proportion of IEIF in the dietary requirement for AA were studied. In experiment 1 three basal CP (20, 60, or 100 g/kg) diets were formulated containing a low CF (LCF, 30 g/kg) or high (HCF, 80 g/kg) level; achieved with cellulose supplementation. All diets were similar in every other respect including having SO content of 40 g/kg. Four floor pens of eight 85-day-old ducks were randomly allocated to each diet. Similar diets were mixed in experiment 2 but corn cob meal replaced cellulose as the fiber source. A high SO (HSO) series was also formed by increasing the SO level from 40 g/kg in the basal series to 100 g/kg. Thus the LCF series was concurrently classified as low SO (LSO) series to control SO effect. Each of the eventual 9 diets were fed to 5 floor pens of ten 65-day-old ducks. Ileal AA flow was measured after a 5 day feeding period in both experiments. Linear regression was calculated between ileal flow and dietary intake of individual AA. The IEIF interpreted as the y-intercept of each linear function responded neither to elevated ingestion of each CF type nor to SO level. Age and DMI had no effect on IEIF computed in relation to BW, but wide discrepancies resulted when related to DMI. Overall IEIF of AA varied between 14.3 to 129.8 mg/kg BW d-1. These flows were established in model computations to account for 10 to 64% of the recommended intake of limiting AA. In conclusion the ileal inevitable flow is constant within the dietary/age conditions investigated. However it is modulated by feed intake and accounts for a significant portion of total amino acid requirement. © 2017 Poultry Science Association Inc.

  7. Accumulation of N and P in the Legume Lespedeza davurica in Controlled Mixtures with the Grass Bothriochloa ischaemum under Varying Water and Fertilization Conditions.

    Science.gov (United States)

    Xu, Bingcheng; Xu, Weizhou; Wang, Zhi; Chen, Zhifei; Palta, Jairo A; Chen, Yinglong

    2018-01-01

    Water and fertilizers affect the nitrogen (N) and phosphorus (P) acquisition and allocation among organs in dominant species in natural vegetation on the semiarid Loess Plateau. This study aimed to clarify the N and P accumulation and N:P ratio at organ and plant level of a local legume species mixed with a grass species under varying water and fertilizer supplies, and thus to fully understand the requirements and balance of nutrient elements in response to growth conditions change of native species. The N and P concentration in the organ (leaf, stem, and root) and plant level of Lespedeza davurica (C 3 legume), were examined when intercropped with Bothriochloa ischaemum (C 4 grass). The two species were grown outdoors in pots under 80, 60, and 40% of soil water field capacity (FC), -NP, +N, +P, and +NP supply and the grass:legume mixture ratios of 2:10, 4:8, 6:6, 8:4, 10:2, and 12:0. The three set of treatments were under a randomized complete block design. Intercropping with B. ischaemum did not affect N concentrations in leaf, stem and root of L. davurica , but reduced P concentration in each organ under P fertilization. Only leaf N concentration in L. davurica showed decreasing trend as soil water content decreased under all fertilization and mixture proportion treatments. Stems had the lowest, while roots had the highest N and P concentration. As the mixture proportion of L. davurica decreased under P fertilization, P concentration in leaf and root also decreased. The N concentration in L. davurica at the whole plant level was 11.1-17.2%. P fertilization improved P concentration, while decreased N:P ratio in L. davurica . The N:P ratios were less than 14.0 under +P and +NP treatments. Our results implied that exogenous N and P fertilizer application may change the N:P stoichiometry and influence the balance between nutrients and organs of native dominant species in natural grassland, and P element should be paid more attention when considering rehabilitating

  8. Accumulation of N and P in the Legume Lespedeza davurica in Controlled Mixtures with the Grass Bothriochloa ischaemum under Varying Water and Fertilization Conditions

    Directory of Open Access Journals (Sweden)

    Bingcheng Xu

    2018-02-01

    Full Text Available Water and fertilizers affect the nitrogen (N and phosphorus (P acquisition and allocation among organs in dominant species in natural vegetation on the semiarid Loess Plateau. This study aimed to clarify the N and P accumulation and N:P ratio at organ and plant level of a local legume species mixed with a grass species under varying water and fertilizer supplies, and thus to fully understand the requirements and balance of nutrient elements in response to growth conditions change of native species. The N and P concentration in the organ (leaf, stem, and root and plant level of Lespedeza davurica (C3 legume, were examined when intercropped with Bothriochloa ischaemum (C4 grass. The two species were grown outdoors in pots under 80, 60, and 40% of soil water field capacity (FC, -NP, +N, +P, and +NP supply and the grass:legume mixture ratios of 2:10, 4:8, 6:6, 8:4, 10:2, and 12:0. The three set of treatments were under a randomized complete block design. Intercropping with B. ischaemum did not affect N concentrations in leaf, stem and root of L. davurica, but reduced P concentration in each organ under P fertilization. Only leaf N concentration in L. davurica showed decreasing trend as soil water content decreased under all fertilization and mixture proportion treatments. Stems had the lowest, while roots had the highest N and P concentration. As the mixture proportion of L. davurica decreased under P fertilization, P concentration in leaf and root also decreased. The N concentration in L. davurica at the whole plant level was 11.1–17.2%. P fertilization improved P concentration, while decreased N:P ratio in L. davurica. The N:P ratios were less than 14.0 under +P and +NP treatments. Our results implied that exogenous N and P fertilizer application may change the N:P stoichiometry and influence the balance between nutrients and organs of native dominant species in natural grassland, and P element should be paid more attention when considering

  9. Regional scenario building as a tool to support vulnerability assessment of food & water security and livelihood conditions under varying natural resources managements

    Science.gov (United States)

    Reinhardt, Julia; Liersch, Stefan; Dickens, Chris; Kabaseke, Clovis; Mulugeta Lemenih, Kassaye; Sghaier, Mongi; Hattermann, Fred

    2013-04-01

    Participatory regional scenario building was carried out with stakeholders and local researchers in four meso-scale case studies (CS) in Africa. In all CS the improvement of food and / or water security and livelihood conditions was identified as the focal issue. A major concern was to analyze the impacts of different plausible future developments on these issues. The process of scenario development is of special importance as it helps to identify main drivers, critical uncertainties and patterns of change. Opportunities and constraints of actors and actions become clearer and reveal adaptation capacities. Effective strategies must be furthermore reasonable and accepted by local stakeholders to be implemented. Hence, developing scenarios and generating strategies need the integration of local knowledge. The testing of strategies shows how they play out in different scenarios and how robust they are. Reasons and patterns of social and natural vulnerability can so be shown. The scenario building exercise applied in this study is inspired by the approach from Peter Schwartz. It aims at determining critical uncertainties and to identify the most important driving forces for a specific focal issue which are likely to shape future developments of a region. The most important and uncertain drivers were analyzed and systematized with ranking exercises during meetings with local researchers and stakeholders. Cause-effect relationships were drawn in the form of concept maps either during the meetings or by researchers based on available information. Past observations and the scenario building outcomes were used to conduct a trend analysis. Cross-comparisons were made to find similarities and differences between CS in terms of main driving forces, patterns of change, opportunities and constraints. Driving forces and trends which aroused consistently over scenarios and CS were identified. First results indicate that livelihood conditions of people rely often directly on the

  10. A cow-level association of ruminal pH on body condition score, serum beta-hydroxybutyrate and postpartum disorders in Thai dairy cattle

    NARCIS (Netherlands)

    Inchaisri, C.; Chanpongsang, S.; Noordhuizen, J.; Hogeveen, H.

    2014-01-01

    Subacute ruminal acidosis in dairy cows occurs when ruminal pH is below about 5.5. However, the exact threshold level of ruminal pH affecting cow health is still in debate. This investigation was carried out in 505 cows within 31 farms. The postpartum disorders, including dystocia, retained

  11. Effects of varying levels of vegetable juice powder and incubation time on color, residual nitrate and nitrite, pigment, pH, and trained sensory attributes of ready-to-eat uncured ham.

    Science.gov (United States)

    Sindelar, J J; Cordray, J C; Sebranek, J G; Love, J A; Ahn, D U

    2007-08-01

    Vegetable juice powder (VJP) and a starter culture containing Staphylococcus carnosus have been identified as necessary ingredients for the manufacture of uncured, no-nitrate/nitrite-added meat products with quality and sensory attributes similar to traditional cured products. The objectives of this study were to determine the effects of varying concentrations of VJP and incubation time (MIN-HOLD) on quality characteristics, including lipid oxidation, color, and cured meat pigment concentrations, of ham over a 90-d storage period, compare residual nitrate and nitrite content, and determine if differences exist in sensory properties of finished products. Four ham treatments (TRT) (TRT 1: 0.20% VJP, 0 MIN-HOLD; TRT 2: 0.20% VJP, 120 MIN-HOLD; TRT 3: 0.35% VJP, 0 MIN-HOLD; TRT 4: 0.35% VJP, 120 MIN-HOLD) and a sodium nitrite-added control (C) were used for this study. No differences (P > 0.05) were observed between TRTs and C for CIE L*, a*, b*, and cured color measured by reflectance ratio. Lipid oxidation (TBARS) for combined TRTs and C revealed little change over time while the C had less (P 0.05) were reported for cured pigment concentration between TRTs and C. Trained sensory panel intensity ratings for ham and vegetable aroma, and flavor, color, and firmness showed that a high concentration (0.35%) of VJP resulted in the highest scores for undesirable vegetable aroma and flavor. Treatment combinations with a low concentration (0.20%) of VJP were comparable to the C for all sensory attributes.

  12. CdSe/ZnS quantum dots conjugated with a fluorescein derivative: a FRET-based pH sensor for physiological alkaline conditions.

    Science.gov (United States)

    Kurabayashi, Tomokazu; Funaki, Nayuta; Fukuda, Takeshi; Akiyama, Shinnosuke; Suzuki, Miho

    2014-01-01

    Dual pH-dependent fluorescence peaks from a semiconductor quantum dot (QD) and a pH-dependent fluorescent dye can be measured by irradiating with a single wavelength light, and the pH can be estimated from the ratio of the fluorescent intensity of the two peaks. In this work, ratiometric pH sensing was achieved in an aqueous environment by a fluorescent CdSe/ZnS QD appended with a pH-sensitive organic dye, based on fluorescence resonance energy transfer (FRET). By functionalizing the CdSe/ZnS QD with 5-(and 6)-carboxynaphthofluorescein succinimidyl ester as a pH-dependent fluorescent dye, we succeeded in fabricating sensitive nanocomplexes with a linear response to a broad range of physiological pH levels (7.5-9.5) when excited at 450 nm. We found that a purification process is important for increasing the high-fluorescence intensity ratio of a ratiometric fluorescence pH-sensor, and the fluorescence intensity ratio was improved up to 1.0 at pH 8.0 after the purification process to remove unreacted CdSe/ZnS QDs even though the fluorescence of the dye could not be observed without the purification process. The fluorescence intensity ratio corresponds to the fluorescence intensity of the dye, and this fluorescent dye exhibited pH-dependent fluorescence intensity changes. These facts indicate that the fluorescence intensity ratio linearly increased with increasing pH value of the buffer solution containing the QD and the dye. The FRET efficiencies changed from 0.3 (pH 7.5) to 6.2 (pH 9.5).

  13. Conditions of Antonin seam exploitation in the open pit Druzba near Sokolov with regard to the protection of thermal and mineral water resources in Karlovy Vary

    International Nuclear Information System (INIS)

    Grmela, A.; Sterba, J.

    1997-01-01

    From new structural-tectonic findings concerning the extent and character of the Nove Sedlo fault in the area of the Druzba open pit in the Sokolov Basin, it is evident that it is a form of listric fault of shallow range, ending in an intermediate slip. This finding has a decisive relevance for deciding as to the current placement of the pit in the protection zone of Karlovy Vary's thermal springs. For the purposes of the exploitation of the Antonin seam, it is necessary to create a network of multipurpose bore holes at the bottom of the pit and in front of the working face for the regulation of pressure in the basal aquifer and to ensure unity of monitoring and its complex evaluation on the basis of numerical modelling of the hydrodynamic state of the basal aquifer and the geotechnical processes of the seam's impermeable bedrock. 4 refs

  14. Tracer Studies to Characterize the Effects of Roadside Noise Barriers on Near-Road Pollutant Dispersion under Varying Atmospheric Stability Conditions

    Science.gov (United States)

    A roadway toxics dispersion study was conducted by the Field Research Division (FRD) of NOAA at the Idaho National Laboratory (INL) near Idaho Falls, ID to document the effects on concentrations of roadway emissions behind a roadside sound barrier in various conditions of atmosph...

  15. Automatically varying the composition of a mixed refrigerant solution for single mixed refrigerant LNG (liquefied natural gas) process at changing working conditions

    International Nuclear Information System (INIS)

    Xu, Xiongwen; Liu, Jinping; Cao, Le; Pang, Weiqiang

    2014-01-01

    The SMR (single mixed refrigerant) process is widely used in the small- and medium-scale liquefaction of NG (natural gas). Operating the MR (mixed-refrigerant) process outside of the design specifications is difficult but essential to save energy. Nevertheless, it is difficult to realize because the process needs to alter the working refrigerant composition. To address this challenge, this study investigated the performance diagnosis mechanism for SMR process. A control strategy was then proposed to control the changes in working refrigerant composition under different working conditions. This strategy separates the working refrigerant flow in the SMR process into three flows through two phase separators before it flows into the cold box. The first liquid flow is rich in the high-temperature component (isopentane). The second liquid flow is rich in the middle-temperature components (ethylene and propane), and the gas flow is rich in the low-temperature components (nitrogen and methane). By adjusting the flow rates, it is easy to decouple the control variables and automate the system. Finally, this approach was validated by process simulation and shown to be highly adaptive and exergy efficient in response to changing working conditions. - Highlights: • The performance diagnosis mechanism of SMR LNG process is studied. • A measure to automatically change the operation composition as per the working conditions is proposed for SMR process. • SMR process simulation is performed to verify the validity of the control solution. • The control solution notably improves the energy efficiency of SMR process at changing working condition

  16. Co-production of lipids, eicosapentaenoic acid, fucoxanthin, and chrysolaminarin by Phaeodactylum tricornutum cultured in a flat-plate photobioreactor under varying nitrogen conditions

    Science.gov (United States)

    Gao, Baoyan; Chen, Ailing; Zhang, Wenyuan; Li, Aifen; Zhang, Chengwu

    2017-10-01

    The marine diatom Phaeodactylum tricornutum is a polymorphological, ecologically significant, and well-studied model of unicellular microalga. This diatom can accumulate diverse important metabolites. Herein, we cultured P. tricornutum in an internally installed tie-piece flat-plate photobioreactor under 14.5 m mol L-1 (high nitrogen, HN) and 2.9 m mol L-1 (low nitrogen, LN) of KNO3 and assessed its time-resolved changes in biochemical compositions. The results showed that HN was inductive to accumulate high biomass (4.1 g L-1). However, the LN condition could accelerate lipid accumulation in P. tricornutum. The maximum total lipid (TL) content under LN was up to 42.5% of biomass on day 12. Finally, neutral lipids (NLs) were 63.8% and 75.7% of TLs under HN and LN, respectively. The content of EPA ranged from 2.3% to 1.5% of dry weight during the growth period under the two culture conditions. Peak volumetric lipid productivity of 128.4 mg L-1d-1 was achieved in the HN group (on day 9). The highest volumetric productivity values of EPA, chrysolaminarin, and fucoxanthin were obtained in the exponential phase (on day 6) under HN, which were 9.6, 93.6, and 4.7 mg L-1d-1, respectively. In conclusion, extractable amounts of lipids, EPA, fucoxanthin, and chrysolaminarin could be obtained from P. tricornutum by regulating the culture conditions.

  17. [Changes of vascular reactivity and reactive oxygen species in conditions of varying duration of permanent stay in the alienation zone in mice].

    Science.gov (United States)

    Tkachenko, M M; Kotsiuruba, A V; Baziliuk, O V; Horot', I V; Sahach, V F

    2010-01-01

    Peculiarities of changes in the vascular reactivity and in the content of reactive forms of oxygen and stable metabolites of nitric oxide (NO) were studied in the aorta preparations of C57BL/6 and BALB/c mice of the two age groups (6 and 18 mo.), which were born and permanently kept in the Chernobyl alienation zone. The results obtained showed a disturbance of acetylcholine-induced endothelium-dependent reactions of relaxation of smooth muscles of the thoracic aorta. A lower level of NO synthesis and lower level of oxidative arginase metabolism of arginine corresponded to a higher degree of damage of endothelium-dependent reactions of relaxation of the thoracic aorta smooth muscles. A decrease of NO synthesis in conditions of permanent effects of low doses of radiation was conditioned by an increase of generation of reactive forms of oxygen, namely, superoxide and hydroxyl radicals, which might be formed in mitochondria. In conditions of permanent effects of low doses of radiation a lesser level of protein nitrosothilation, same as lesser one of generation of OH-radical, corresponded to a higher level of damage of endothelium-dependent reactions.

  18. A new luminescence dating chronology for the Rhafas cave site (NE Morocco): Insights into Palaeolithic human cultural change under varying palaeoenvironmental conditions in the Maghreb

    Science.gov (United States)

    Dörschner, Nina; Fitzsimmons, Kathryn E.; Ditchfield, Peter; McLaren, Sue J.; Steele, Teresa E.; Zielhofer, Christoph; McPherron, Shannon P.; Bouzouggar, Abdeljalil; Hublin, Jean-Jacques

    2016-04-01

    Archaeological sites in northern Africa provide a rich record that is of increasing importance for current debates relating to the origins of modern human behaviour and to Out of Africa human dispersal events. Particular interest is placed on the cultural transition between the North African Middle Stone Age (MSA) and Late Stone Age (LSA), and the need for accurately defined chronologies, however the timing and nature of Palaeolithic human behaviour and dispersal across north-western Africa (the Maghreb) and potential correlation with environmental conditions remain poorly understood. The inland cave site of Rhafas (Morocco) preserves a long stratified sequence providing valuable chronological information about cultural changes in the Maghreb spanning the North African MSA through to the Neolithic. In this study, we apply optically stimulated luminescence (OSL) dating on sand-sized quartz grains to the cave deposits of Rhafas as well as to a section on the terrace in front of the cave entrance. Single grain OSL dating reliably constrains the timing of technocomplexes beyond the limits of radiocarbon by directly dating sediment associated with archaeological traces. We combine OSL dating with multi-proxy geological investigations (XRF, grain size analyses, stable isotopes, thin sections) to investigate site formation processes and reconstruct palaeoenvironmental conditions during human occupation phases at Rhafas. Our results indicate that the occupation of the site started at least in MIS 6 during a phase of relatively arid environmental conditions. Climatic amelioration after c.140 ka is associated with a change in sediment geochemistry at the site, most likely linked to a change in sediment source due to shifting wind directions. Tanged pieces - typical for the classical Aterian technocomplex - start to occur in the archaeological sequence in MIS 5, consistent with previously published chronological data from the Maghreb. From 55 ka, climatic conditions were

  19. A Comparative Study of Environmental Conditions, Bee Management and the Epidemiological Situation in Apiaries Varying in the Level of Colony Losses

    Directory of Open Access Journals (Sweden)

    Pohorecka Krystyna

    2014-12-01

    Full Text Available Explaining the reasons for the increased mortality of the honey bee (Apis mellifera L. in recent years, in Europe and North America, has become a global research priority in apicultural science. Our project was aimed at determining the relationship between environmental conditions, beekeeping techniques, the epidemiological situation of pathogens, and the mortality rate of bee colonies. Dead bee samples were collected by beekeepers from 2421 colonies. The samples were examined for the presence of V. destructor, Nosema spp. (Nosema apis and Nosema ceranae, chronic bee paralysis virus (CBPV, acute bee paralysis virus (ABPV, deformed wing virus (DWV, and Israeli acute paralysis virus (IAPV.

  20. Projected atoll shoreline and run-up changes in response to sea-level rise and varying large wave conditions at Wake and Midway Atolls, Northwestern Hawaiian Islands

    Science.gov (United States)

    Shope, James B.; Storlazzi, Curt D.; Hoeke, Ron K.

    2017-10-01

    Atoll islands are dynamic features that respond to seasonal alterations in wave conditions and sea level. It is unclear how shoreline wave run-up and erosion patterns along these low elevation islands will respond to projected sea-level rise (SLR) and changes in wave climate over the next century, hindering communities' preparation for the future. To elucidate how these processes may respond to climate change, extreme boreal winter and summer wave conditions under future sea-level rise (SLR) and wave climate scenarios were simulated at two atolls, Wake and Midway, using a shallow-water hydrodynamic model. Nearshore wave conditions were used to compute the potential longshore sediment flux along island shorelines via the CERC empirical formula and wave-driven erosion was calculated as the divergence of the longshore drift; run-up and the locations where the run-up exceed the berm elevation were also determined. SLR is projected to predominantly drive future island morphological change and flooding. Seaward shorelines (i.e., ocean fronted shorelines directly facing incident wave energy) were projected to experience greater erosion and flooding with SLR and in hypothetical scenarios where changes to deep water wave directions were altered, as informed by previous climate change forced Pacific wave modeling efforts. These changes caused nearshore waves to become more shore-normal, increasing wave attack along previously protected shorelines. With SLR, leeward shorelines (i.e., an ocean facing shoreline but sheltered from incident wave energy) became more accretive on windward islands and marginally more erosive along leeward islands. These shorelines became more accretionary and subject to more flooding with nearshore waves becoming more shore-normal. Lagoon shorelines demonstrated the greatest SLR-driven increase in erosion and run-up. They exhibited the greatest relative change with increasing wave heights where both erosion and run-up magnitudes increased. Wider

  1. Projected atoll shoreline and run-up changes in response to sea-level rise and varying large wave conditions at Wake and Midway Atolls, Northwestern Hawaiian Islands

    Science.gov (United States)

    Shope, James B.; Storlazzi, Curt; Hoeke, Ron

    2017-01-01

    Atoll islands are dynamic features that respond to seasonal alterations in wave conditions and sea level. It is unclear how shoreline wave run-up and erosion patterns along these low elevation islands will respond to projected sea-level rise (SLR) and changes in wave climate over the next century, hindering communities' preparation for the future. To elucidate how these processes may respond to climate change, extreme boreal winter and summer wave conditions under future sea-level rise (SLR) and wave climate scenarios were simulated at two atolls, Wake and Midway, using a shallow-water hydrodynamic model. Nearshore wave conditions were used to compute the potential longshore sediment flux along island shorelines via the CERC empirical formula and wave-driven erosion was calculated as the divergence of the longshore drift; run-up and the locations where the run-up exceed the berm elevation were also determined. SLR is projected to predominantly drive future island morphological change and flooding. Seaward shorelines (i.e., ocean fronted shorelines directly facing incident wave energy) were projected to experience greater erosion and flooding with SLR and in hypothetical scenarios where changes to deep water wave directions were altered, as informed by previous climate change forced Pacific wave modeling efforts. These changes caused nearshore waves to become more shore-normal, increasing wave attack along previously protected shorelines. With SLR, leeward shorelines (i.e., an ocean facing shoreline but sheltered from incident wave energy) became more accretive on windward islands and marginally more erosive along leeward islands. These shorelines became more accretionary and subject to more flooding with nearshore waves becoming more shore-normal. Lagoon shorelines demonstrated the greatest SLR-driven increase in erosion and run-up. They exhibited the greatest relative change with increasing wave heights where both erosion and run-up magnitudes increased. Wider

  2. Estimating pesticide sampling rates by the polar organic chemical integrative sampler (POCIS) in the presence of natural organic matter and varying hydrodynamic conditions

    International Nuclear Information System (INIS)

    Charlestra, Lucner; Amirbahman, Aria; Courtemanch, David L.; Alvarez, David A.; Patterson, Howard

    2012-01-01

    The polar organic chemical integrative sampler (POCIS) was calibrated to monitor pesticides in water under controlled laboratory conditions. The effect of natural organic matter (NOM) on the sampling rates (R s ) was evaluated in microcosms containing −1 of total organic carbon (TOC). The effect of hydrodynamics was studied by comparing R s values measured in stirred (SBE) and quiescent (QBE) batch experiments and a flow-through system (FTS). The level of NOM in the water used in these experiments had no effect on the magnitude of the pesticide sampling rates (p > 0.05). However, flow velocity and turbulence significantly increased the sampling rates of the pesticides in the FTS and SBE compared to the QBE (p < 0.001). The calibration data generated can be used to derive pesticide concentrations in water from POCIS deployed in stagnant and turbulent environmental systems without correction for NOM. - Highlights: ► We assessed the effect of TOC and stirring on pesticide sampling rates by POCIS. ► Total organic carbon (TOC) had no effect on the sampling rates. ► Water flow and stirring significantly increased the magnitude of the sampling rates. ► The sampling rates generated are directly applicable to field conditions. - This study provides POCIS sampling rates data that can be used to estimate freely dissolved concentrations of toxic pesticides in natural waters.

  3. Influence of pH and media composition on suspension stability of silver, zinc oxide, and titanium dioxide nanoparticles and immobilization of Daphnia magna under guideline testing conditions

    DEFF Research Database (Denmark)

    Cupi, Denisa; Hartmann, Nanna B.; Baun, Anders

    2016-01-01

    sterically stabilized, test suspensions of silver (Ag) ENPs formed large agglomerates in both VS EPA and M7 media; and toxicity was found to be higher in VS EPA medium due to increased dissolution. Low-agglomerate suspensions for zinc oxide (ZnO) could be obtained at pH 7 in VS EPA medium, but the increase...

  4. Estimating pesticide sampling rates by the polar organic chemical integrative sampler (POCIS) in the presence of natural organic matter and varying hydrodynamic conditions

    Science.gov (United States)

    Charlestra, Lucner; Amirbahman, Aria; Courtemanch, David L.; Alvarez, David A.; Patterson, Howard

    2012-01-01

    The polar organic chemical integrative sampler (POCIS) was calibrated to monitor pesticides in water under controlled laboratory conditions. The effect of natural organic matter (NOM) on the sampling rates (Rs) was evaluated in microcosms containing -1 of total organic carbon (TOC). The effect of hydrodynamics was studied by comparing Rs values measured in stirred (SBE) and quiescent (QBE) batch experiments and a flow-through system (FTS). The level of NOM in the water used in these experiments had no effect on the magnitude of the pesticide sampling rates (p > 0.05). However, flow velocity and turbulence significantly increased the sampling rates of the pesticides in the FTS and SBE compared to the QBE (p < 0.001). The calibration data generated can be used to derive pesticide concentrations in water from POCIS deployed in stagnant and turbulent environmental systems without correction for NOM.

  5. A Mathematical Model of Hourly Solar Radiation in Varying Weather Conditions for a Dynamic Simulation of the Solar Organic Rankine Cycle

    Directory of Open Access Journals (Sweden)

    Taehong Sung

    2015-07-01

    Full Text Available A mathematical model of hourly solar radiation with weather variability is proposed based on the simple sky model. The model uses a superposition of trigonometric functions with short and long periods. We investigate the effects of the model variables on the clearness (kD and the probability of persistence (POPD indices and also evaluate the proposed model for all of the kD-POPD weather classes. A simple solar organic Rankine cycle (SORC system with thermal storage is simulated using the actual weather conditions, and then, the results are compared with the simulation results using the proposed model and the simple sky model. The simulation results show that the proposed model provides more accurate system operation characteristics than the simple sky model.

  6. PhD students and integrative research

    NARCIS (Netherlands)

    Fry, G.; Tress, B.; Tress, G.

    2006-01-01

    The training of PhD students is currently very dynamic and varies widely from place to place. We present some examples of this variation and comment on how it may affect the way PhD students cope with integrative studies. Our focus is on the training needs of PhD students studying integrative

  7. Straw incorporation increases crop yield and soil organic carbon sequestration but varies under different natural conditions and farming practices in China: a system analysis

    Directory of Open Access Journals (Sweden)

    X. Han

    2018-04-01

    Full Text Available Loss of soil organic carbon (SOC from agricultural soils is a key indicator of soil degradation associated with reductions in net primary productivity in crop production systems worldwide. Technically simple and locally appropriate solutions are required for farmers to increase SOC and to improve cropland management. In the last 30 years, straw incorporation (SI has gradually been implemented across China in the context of agricultural intensification and rural livelihood improvement. A meta-analysis of data published before the end of 2016 was undertaken to investigate the effects of SI on crop production and SOC sequestration. The results of 68 experimental studies throughout China in different edaphic conditions, climate regions and farming regimes were analyzed. Compared with straw removal (SR, SI significantly sequestered SOC (0–20 cm depth at the rate of 0.35 (95 % CI, 0.31–0.40 Mg C ha−1 yr−1, increased crop grain yield by 13.4 % (9.3–18.4 % and had a conversion efficiency of the incorporated straw C of 16 % ± 2 % across China. The combined SI at the rate of 3 Mg C ha−1 yr−1 with mineral fertilizer of 200–400 kg N ha−1 yr−1 was demonstrated to be the best farming practice, where crop yield increased by 32.7 % (17.9–56.4 % and SOC sequestrated by the rate of 0.85 (0.54–1.15 Mg C ha−1 yr−1. SI achieved a higher SOC sequestration rate and crop yield increment when applied to clay soils under high cropping intensities, and in areas such as northeast China where the soil is being degraded. The SOC responses were highest in the initial starting phase of SI, then subsequently declined and finally became negligible after 28–62 years. However, crop yield responses were initially low and then increased, reaching their highest level at 11–15 years after SI. Overall, our study confirmed that SI created a positive feedback loop of SOC enhancement together with

  8. Straw incorporation increases crop yield and soil organic carbon sequestration but varies under different natural conditions and farming practices in China: a system analysis

    Science.gov (United States)

    Han, Xiao; Xu, Cong; Dungait, Jennifer A. J.; Bol, Roland; Wang, Xiaojie; Wu, Wenliang; Meng, Fanqiao

    2018-04-01

    Loss of soil organic carbon (SOC) from agricultural soils is a key indicator of soil degradation associated with reductions in net primary productivity in crop production systems worldwide. Technically simple and locally appropriate solutions are required for farmers to increase SOC and to improve cropland management. In the last 30 years, straw incorporation (SI) has gradually been implemented across China in the context of agricultural intensification and rural livelihood improvement. A meta-analysis of data published before the end of 2016 was undertaken to investigate the effects of SI on crop production and SOC sequestration. The results of 68 experimental studies throughout China in different edaphic conditions, climate regions and farming regimes were analyzed. Compared with straw removal (SR), SI significantly sequestered SOC (0-20 cm depth) at the rate of 0.35 (95 % CI, 0.31-0.40) Mg C ha-1 yr-1, increased crop grain yield by 13.4 % (9.3-18.4 %) and had a conversion efficiency of the incorporated straw C of 16 % ± 2 % across China. The combined SI at the rate of 3 Mg C ha-1 yr-1 with mineral fertilizer of 200-400 kg N ha-1 yr-1 was demonstrated to be the best farming practice, where crop yield increased by 32.7 % (17.9-56.4 %) and SOC sequestrated by the rate of 0.85 (0.54-1.15) Mg C ha-1 yr-1. SI achieved a higher SOC sequestration rate and crop yield increment when applied to clay soils under high cropping intensities, and in areas such as northeast China where the soil is being degraded. The SOC responses were highest in the initial starting phase of SI, then subsequently declined and finally became negligible after 28-62 years. However, crop yield responses were initially low and then increased, reaching their highest level at 11-15 years after SI. Overall, our study confirmed that SI created a positive feedback loop of SOC enhancement together with increased crop production, and this is of great practical importance to straw management as agriculture

  9. Sulfate reduction during the acidification of sucrose at pH 5 under thermophilic (55 degrees C) conditions. I: Effect of trace metals

    NARCIS (Netherlands)

    Lopes, S.I.C.; Capela, M.I.; Lens, P.N.L.

    2010-01-01

    This work studied the effect of supplying trace metals (7.5 mu M Fe and 0.5 mu M Co, Ni, Mn, Zn, Cu, B, Se, Mo and W) on sulfate reduction and acidification in thermophilic (55 degrees C) UASB reactors fed with sucrose (4 gCOD (I-reactor d)(-1)) operated at a reactor mixed liquor pH controlled at 5.

  10. First results on T91 claddings with and without modified FeCrAlY coatings exposed in PbBi under varying conditions

    International Nuclear Information System (INIS)

    Weisenburger, A.; Heinzel, A.; Miller, G.; Rousanov, A.

    2008-01-01

    It is well known that at temperatures above 500 deg C low activation austenitic steels suffer from severe corrosion in lead or lead-bismuth. Low activation martensitic steels instead form under similar conditions concerning temperature and oxygen content thick oxide scales that periodically may span off. Both groups of materials are therefore restricted to areas having lower temperature load. For parts that are intended to be used in high-temperature regions, like claddings, surface protection has to be applied. From gas turbines the role of elements forming thin stable oxide scales is well understood. The concept chosen here for thermally high loaded parts, the claddings, is the deposition of a FeCrAlY coating of about 30 vt,m thickness that is afterwards re-melted applying a pulsed electron beam (GESA). The beam energy is adjusted in a way to melt the entire coating together with a few thin region of the bulk to create a perfect intermixing at the boundary. This results in a new surface area of the cladding with an aluminium content of the order of 5 wt.% that will be sufficiently high to grow thin stable oxide scales. This concept is proven for austenitic cladding materials like 1.4970 as well as for martensitic ones like T91. In long-term corrosion tests the compatibility to Pb or PbBi, the resistance against corrosion and severe oxidation, was clearly demonstrated. No negative response of such a modified coating on the mechanical properties and the stability under irradiation has been observed as of yet. This paper will focus on the surface modification process, the corrosion results thus far obtained and on the evaluation of some mechanical properties. For example, the swelling of the fuel by irradiation will lead during operation to an increase of the internal pressure. This is simulated in experiments where an internal pressure of defined value was applied on T91 cladding tubes. The influence of flow velocity between to 3 m/s on the oxidation behaviour of T

  11. 3D printing conditions determination for feedstock used in fused filament fabrication (FFF of 17-4PH stainless steel parts

    Directory of Open Access Journals (Sweden)

    J. Gonzalez-Gutierez

    2018-01-01

    Full Text Available Fused filament fabrication combined with debinding and sintering could be an economical process for 3D printing of metal parts. In this study, compounding, filament making and FFF processing of a feedstock material containing 55 vol. % of 17-4PH stainless steel powder and a multicomponent binder system are presented. For the FFF process, processing windows of the most significant parameters, such as range of extrusion temperatures (210 to 260 °C, flow rate multipliers (150 to 200 %, and 3D printing speed multipliers (60 to 100 % were determined for a constant printing bed temperature of 60 °C.

  12. pH controls over methanogenesis and iron reduction along soil depth profile in Arctic tundra

    Science.gov (United States)

    Zheng, J.; Gu, B.; Wullschleger, S. D.; Graham, D. E.

    2017-12-01

    Increasing soil temperature in the Arctic is expected to accelerate rates of soil organic matter decomposition. However, the magnitude of this impact is uncertain due to the many physical, chemical, and biological processes that control the decomposition pathways. Varying soil redox conditions present a key control over pathways of organic matter decomposition by diverting the flow of reductants among different electron accepting processes and further driving acid-base reactions that alter soil pH. In this study we investigated the pH controls over anaerobic carbon mineralization, methanogenesis, Fe(III) reduction and the interplay between these processes across a range of pH and redox conditions. pH manipulation experiments were conducted by incubating soils representing organic, mineral, cryoturbated transitional layers and permafrost. In the experiments we sought to understand (1) if methanogenesis or Fe(III) reduction had similar pH optima; (2) if this pH response also occurs at `upstream' fermentation process; and (3) if pH alters organo-mineral association or organic matter sorption and desorption and its availability for microbial degradation. Our preliminary results suggest that the common bell-shaped pH response curve provides a good fit for both Fe(III) reduction and methanogenesis, with optimum pH at 6.0-7.0. Exceptions to this were found in transitional layer where methanogenesis rates positively correlated with increasing pH, with maximum rates measured at pH 8.5. It is likely that the transitional layer harbors distinct groups of methanogens that prefer a high pH. Variations in the optimum pH of Fe(III) reduction and methanogenesis may play a significant role in regulating organic matter decomposition pathways and thus greenhouse gas production in thawing soils. These results support biogeochemical modeling efforts to accurately simulate organic matter decomposition under changing redox and pH conditions.

  13. Joint route planning under varying market conditions

    NARCIS (Netherlands)

    Cruijssen, Frans; Bräysy, Olli; Dullaert, Wout; Fleuren, Hein; Salomon, Marc

    2007-01-01

    Purpose - To provide empirical evidence on the level of savings that can be attained by joint route planning and how these savings depend on specific market characteristics. Design/methodology/approach - Joint route planning is a measure that companies can take to decrease the costs of their

  14. RNA Binding of T-cell Intracellular Antigen-1 (TIA-1) C-terminal RNA Recognition Motif Is Modified by pH Conditions*

    Science.gov (United States)

    Cruz-Gallardo, Isabel; Aroca, Ángeles; Persson, Cecilia; Karlsson, B. Göran; Díaz-Moreno, Irene

    2013-01-01

    T-cell intracellular antigen-1 (TIA-1) is a DNA/RNA-binding protein that regulates critical events in cell physiology by the regulation of pre-mRNA splicing and mRNA translation. TIA-1 is composed of three RNA recognition motifs (RRMs) and a glutamine-rich domain and binds to uridine-rich RNA sequences through its C-terminal RRM2 and RRM3 domains. Here, we show that RNA binding mediated by either isolated RRM3 or the RRM23 construct is controlled by slight environmental pH changes due to the protonation/deprotonation of TIA-1 RRM3 histidine residues. The auxiliary role of the C-terminal RRM3 domain in TIA-1 RNA recognition is poorly understood, and this work provides insight into its binding mechanisms. PMID:23902765

  15. Optimized conditions for primary culture of pituitary cells from the Atlantic cod (Gadus morhua). The importance of osmolality, pCO₂, and pH.

    Science.gov (United States)

    Hodne, Kjetil; von Krogh, Kristine; Weltzien, Finn-Arne; Sand, Olav; Haug, Trude M

    2012-09-01

    Protocols for primary cultures of teleost cells are commonly only moderately adjusted from similar protocols for mammalian cells, the main adjustment often being of temperature. Because aquatic habitats are in general colder than mammalian body temperatures and teleosts have gills in direct contact with water, pH and buffer capacity of blood and extracellular fluid are different in fish and mammals. Plasma osmolality is generally higher in marine teleosts than in mammals. Using Atlantic cod (Gadus morhua) as a model, we have optimized these physiological parameters to maintain primary pituitary cells in culture for an extended period without loosing key properties. L-15 medium with adjusted osmolality, adapted to low pCO(2) (3.8mm Hg) and temperature (12°C), and with pH 7.85, maintained the cells in a physiologically sounder state than traditional culture medium, significantly improving cell viability compared to the initial protocol. In the optimized culture medium, resting membrane potential and response to releasing hormone were stable for at least two weeks, and the proportion of cells firing action potentials during spawning season was about seven times higher than in the original culture medium. The cells were moderately more viable when the modified medium was supplemented with newborn calf serum or artificial serum substitute. Compared to serum-free L-15 medium, expression of key genes (lhb, fshb, and gnrhr2a) was better maintained in medium containing SSR, whereas NCS tended to decrease the expression level. Although serum-free medium is adequate for many applications, serum supplement may be preferable for experiments dependent on membrane integrity. Copyright © 2012 Elsevier Inc. All rights reserved.

  16. Biotite and chlorite weathering at 25 degrees C: the dependence of pH and (bi)carbonate on weathering kinetics, dissolution stoichiometry, and solubility; and the relation to redox conditions in granitic aquifers

    Energy Technology Data Exchange (ETDEWEB)

    Malmstroem, M.; Banwart, S. [Royal Inst. of Technology, Stockholm (Sweden). Dept. of Inorganic Chemistry; Duro, L. [Universidad Politecnica de Cataluna, Barcelona (Spain). Dept. de Ingneria Quimica; Wersin, P.; Bruno, J. [MBT Technologia Ambiental, Cerdanyola (Spain)

    1995-01-01

    We have studied the kinetics and thermodynamics of biotite and chlorite weathering in the pH range 2<pH<10 at 25 degrees C. The dissolution is highly non-stoichiometric and pH dependent in the whole pH region. By XPD we have identified a clay mineral to be the main weathering product formed. A model of biotite dissolution and the formation of secondary solubility controlling minerals, such as Fe(III)-hydroxide, Na-clay, quartz and gibbsite is used to explain experimental equilibrium concentrations of silicon, iron, aluminium and magnesium. The model predict redox potentials in the range of -200-400 mV at neutral pH and qualitatively agrees with field data reported in the literature. We use observed iron release rate to make conservative estimates of timescales of 1. the depletion of molecular oxygen from deep aquifers (810{sup 2}-10{sup 2} year); and 2. the development of characteristic Fe(III) concentrations (10{sup -5} M in 10{sup -}1 years). The Fe(III)-bearing clay minerals formed during these experiments are similar to the fracture-filling-material observed at the Aespoe Hard Rock Laboratory. Such clays can provide reducing capacity to a repository. They can help maintain anoxic conditions by consuming oxygen that enters the repository during the construction and operation phases thereby helping maintain the redox stability of the repository regarding canister corrosion. The half-life of oxygen trapped in the repository at the time of closure depends on the rate of oxygen uptake by Fe(II) minerals, sulfide minerals and organic carbon. Fe(II)-clay minerals are important to the redox stability of a repository, as well as providing a sorption barrier to radionuclide migration. 107 refs, 52 figs, 35 tabs.

  17. Title: Elucidation of Environmental Fate of Artificial Sweeteners (Aspartame, Acesulfame K and Saccharin) by Determining Bimolecular Rate Constants with Hydroxyl Radical at Various pH and Temperature Conditions and Possible Reaction By-Products

    Science.gov (United States)

    Teraji, T.; Arakaki, T.; Suzuka, T.

    2012-12-01

    Use of artificial sweeteners in beverages and food has been rapidly increasing because of their non-calorie nature. In Japan, aspartame, acesulfame K and sucralose are among the most widely used artificial sweeteners. Because the artificial sweeteners are not metabolized in human bodies, they are directly excreted into the environment without chemical transformations. We initiated a study to better understand the fate of artificial sweeteners in the marine environment. The hydroxyl radical (OH), the most potent reactive oxygen species, reacts with various compounds and determines the environmental oxidation capacity and the life-time of many compounds. The steady-state OH concentration and the reaction rate constants between the compound and OH are used to estimate the life-time of the compound. In this study, we determine the bimolecular rate constants between aspartame, acefulfame K and saccharin and OH at various pH and temperature conditions using a competition kinetics technique. We use hydrogen peroxide as a photochemical source of OH. Bimolecular rate constant we obtained so far for aspartame was (2.6±1.2)×109 M-1 s-1 at pH = 3.0 and (4.9±2.3)×109 M-1 s-1 at pH = 5.5. Little effect was seen by changing the temperatures between 15 and 40 oC. Activation energy (Ea) was calculated to be -1.0 kJ mol-1 at pH = 3.0, +8.5 kJ mol-1 at pH = 5.5, which could be regarded as zero. We will report bimolecular rate constants at different pHs and temperatures for acesulfame K and saccharin, as well. Possible reaction by-products for aspartame will be also reported. We will further discuss the fate of aspartame in the coastal environment.

  18. Optimization of culture conditions (sucrose, pH, and photoperiod) for in vitro regeneration and early detection of somaclonal variation in ginger lime (Citrus assamensis).

    Science.gov (United States)

    Yaacob, Jamilah Syafawati; Mahmad, Noraini; Mat Taha, Rosna; Mohamed, Normadiha; Mad Yussof, Anis Idayu; Saleh, Azani

    2014-01-01

    Various explants (stem, leaf, and root) of Citrus assamensis were cultured on MS media supplemented with various combinations and concentrations (0.5-2.0 mg L(-1)) of NAA and BAP. Optimum shoot and root regeneration were obtained from stem cultures supplemented with 1.5 mg L(-1) NAA and 2.0 mg L(-1) BAP, respectively. Explant type affects the success of tissue culture of this species, whereby stem explants were observed to be the most responsive. Addition of 30 gL(-1) sucrose and pH of 5.8 was most optimum for in vitro regeneration of this species. Photoperiod of 16 hours of light and 8 hours of darkness was most optimum for shoot regeneration, but photoperiod of 24 hours of darkness was beneficial for production of callus. The morphology (macro and micro) and anatomy of in vivo and in vitro/ex vitro Citrus assamensis were also observed to elucidate any irregularities (or somaclonal variation) that may arise due to tissue culture protocols. Several minor micromorphological and anatomical differences were observed, possibly due to stress of tissue culture, but in vitro plantlets are expected to revert back to normal phenotype following full adaptation to the natural environment.

  19. Identification of bioactive compounds from jambolão (Syzygium cumini) and antioxidant capacity evaluation in different pH conditions.

    Science.gov (United States)

    Faria, Adelia F; Marques, Marcella C; Mercadante, Adriana Z

    2011-06-15

    The composition of carotenoids and phenolic compounds from jambolão fruits (Syzygium cumini) was determined by HPLC-DAD-MS/MS. Two main carotenoids were found in the fruits, all-trans-lutein (43.7%) and all-trans-β-carotene (25.4%). The anthocyanin composition was characterised by the presence of 3,5-diglucosides of five out of six aglycones commonly found in foods. This pattern was also observed for the other flavonoids, since diglucosides of dihydromyricetin, methyl-dihydromyricetin and dimethyl-dihydromyricetin, along with myricetin glucoside and a galloyl-glucose ester were identified. Furthermore, the antioxidant capacity of a functional extract rich in anthocyanins was evaluated through the scavenging capacities of ABTS(+) and peroxyl radical (ORAC) and the protective effect against singlet oxygen ((1)O2). The TEAC values indicated that the hemiacetals/chalcones and quinonoidal bases species (pH⩾5) possess higher scavenging capacity as compared to the flavylium cation (pH<3). The functional extract also showed 60% of dimethylanthracene protection against (1)O2 and an ORAC value of 16.4μmolTrolox/gfruit. Copyright © 2010 Elsevier Ltd. All rights reserved.

  20. PENENTUAN WAKTU KONTAK DAN pH OPTIMUM PENYERAPAN METILEN BIRU MENGGUNAKAN ABU SEKAM PADI

    Directory of Open Access Journals (Sweden)

    Anung Riapanitra

    2006-11-01

    Full Text Available Dyes are widely used for colouring in textile industries, significant losses occur during the manufacture and processing of the product, and these lost chemical are discharged in surrounding effluent. Adsorption of dyes is an effective technology for treatment of wastewater contaminated by the mismanaged of different types of dyes. In this research, we investigated the potential of rice husk ash for removal of methylene blue dyeing agent in aqueous system. The aim of this research is to find out the optimum contact time and pH on the adsorption of methylene blue using rice husk ash. Batch kinetics studies were carried out under varying experimental condition of contact time and pH. An adsorption equilibrium condition was reached within 10 minutes and the optimum condition for adsorption was at pH 3. The adsorption of methylene blue was decreasing with decreasing the solution pH value.

  1. Hidrólise da uréia em latossolos: efeito da concentração de uréia, temperatura, pH, armazenamento e tempo de incubação Urea hydrolysis in oxisols: effects of substrate concentration, temperature, pH, incubation time and storage conditions

    Directory of Open Access Journals (Sweden)

    Regina Marcia Longo

    2005-07-01

    Full Text Available Este trabalho objetivou estudar a velocidade de hidrólise da uréia em dois diferentes solos brasileiros (Latossolo Vermelho Aluminoférrico típico e Latossolo Vermelho distrófico típico onde foram realizados ensaios sobre o efeito do tempo e condições de armazenamento, concentração do substrato (uréia, temperatura, pH e tempo de incubação sobre a atividade da urease. As melhores condições de armazenamento foram em temperatura ambiente ou 5 ºC, após secagem ao ar, por um período de até 7 dias; para as condições estudadas, o melhor tempo de incubação foi de uma hora a 25-30 ºC, sem a utilização de tampão para acertar o pH, e a concentração de uréia suficiente foi de 3,30 g L-1, para o Latossolo Vermelho Aluminoférrico típico, e de 2,5 g L-1, para o Latossolo Vermelho distrófico típico para obter a velocidade máxima da enzima.This study evaluated the kinetics of urease hydrolysis in two different Brazilian soils (Rhodic Oxisols: a typic alumino-ferric Red Latossol and a typic distrophic Red Latosol. The trials were carried out to study the effects of air drying, soil sampling, storage conditions and temperature, pH, time of incubation, and substrate concentration on the urease activity. Results showed that best conditions for soil sample storage after air-drying for a 7-day period were at room temperature or at a temperature of 5 ºC. For the studied conditions the best incubation time was one hour at 25-30 ºC, without pH buffering. The ideal urea concentration suggested for the detection of the maximum velocity was 3.3 g L-1 for the typic alumino-ferric Red Latossol and 2.5 g L-1 for the typic distrophic Red Latosol.

  2. Zn(II, Mn(II and Sr(II Behavior in a Natural Carbonate Reservoir System. Part I: Impact of Salinity, Initial pH and Initial Zn(II Concentration in Atmospheric Conditions

    Directory of Open Access Journals (Sweden)

    Auffray B.

    2016-07-01

    Full Text Available The sorption of inorganic elements on carbonate minerals is well known in strictly controlled conditions which limit the impact of other phenomena such as dissolution and/or precipitation. In this study, we evidence the behavior of Zn(II (initially in solution and two trace elements, Mn(II and Sr(II (released by carbonate dissolution in the context of a leakage from a CO2 storage site. The initial pH chosen are either equal to the pH of the water-CO2 equilibrium (~ 2.98 or equal to the pH of the water-CO2-calcite system (~ 4.8 in CO2 storage conditions. From this initial influx of liquid, saturated or not with respect to calcite, the batch experiments evolve freely to their equilibrium, as it would occur in a natural context after a perturbation. The batch experiments are carried out on two natural carbonates (from Lavoux and St-Emilion with PCO2 = 10−3.5 bar, with different initial conditions ([Zn(II]i from 10−4 to 10−6 M, either with pure water or 100 g/L NaCl brine. The equilibrium regarding calcite dissolution is confirmed in all experiments, while the zinc sorption evidenced does not always correspond to the two-step mechanism described in the literature. A preferential sorption of about 10% of the concentration is evidenced for Mn(II in aqueous experiments, while Sr(II is more sorbed in saline conditions. This study also shows that this preferential sorption, depending on the salinity, is independent of the natural carbonate considered. Then, the simulations carried out with PHREEQC show that experiments and simulations match well concerning the equilibrium of dissolution and the sole zinc sorption, with log KZn(II ~ 2 in pure water and close to 4 in high salinity conditions. When the simulations were possible, the log K values for Mn(II and Sr(II were much different from those in the literature obtained by sorption in controlled conditions. It is shown that a new conceptual model regarding multiple Trace Elements (TE sorption is

  3. Influence of pH of spray solution on optoelectronic properties of cadmium oxide thin films

    International Nuclear Information System (INIS)

    Hodlur, R. M.; Rabinal, M. K.

    2015-01-01

    Highly conducting transparent cadmium oxide thin films were prepared by the conventional spray pyrolysis technique. The pH of the spray solution is varied by adding ammonia/hydrochloric acid. The effect of pH on the morphology, crystallinity and optoelectronic properties of these films is studied. The structural analysis showed all the films in the cubic phase. For the films with pH < 7 (acidic condition), the preferred orientation is along the (111) direction and for those with pH >7 (alkaline condition), the preferred orientation is along the (200) direction. A lowest resistivity of 9.9 × 10 −4 Ω·cm (with carrier concentration = 5.1 × 10 20 cm −3 , mobility = 12.4 cm 2 /(V·s)) is observed for pH ≈ 12. The resistivity is tuned almost by three orders of magnitude by controlling the bath pH with optical transmittance more than 70%. Thus, the electrical conductivity of CdO films could be easily tuned by simply varying the pH of the spray solution without compromising the optical transparency. (paper)

  4. Ph3CCOOSnPh3.Ph3PO AND Ph3CCOOSnPh3.Ph3AsO: SYNTHESIS AND INFRARED STUDY

    Directory of Open Access Journals (Sweden)

    ABDOU MBAYE

    2014-08-01

    Full Text Available The mixture of ethanolic solutions of Ph3CCOOSnPh3 and Ph3PO or Ph3AsO gives Ph3CCOOSnPh3.Ph3PO and Ph3CCOOSnPh3.Ph3AsO adducts which have been characterized by infrared spectroscopy. A discrete structure is suggested for both, the environment around the tin centre being trigonal bipyramidal, the triphenylacetate anion behaving as a mondentate ligand.

  5. Integrated combined effects of temperature, pH and sodium chloride concentration on biofilm formation by Salmonella enterica ser. Enteritidis and Typhimurium under low nutrient food-related conditions.

    Science.gov (United States)

    Iliadis, Ioannis; Daskalopoulou, Aikaterini; Simões, Manuel; Giaouris, Efstathios

    2018-05-01

    Salmonella enterica is a major foodborne bacterial pathogen. This forms biofilms on surfaces and persists, depending on the strain and the environment. The integrative interaction of temperature (T; 13-39 °C), pH (5-8) and sodium chloride (NaCl) concentration (0.5-8.5%) on biofilm formation by two S. enterica strains (ser. Enteritidis and Typhimurium) was here evaluated under low nutrient conditions. This was achieved using response surface methodology to model the combined effect of each factor on the response, through mathematical quadratic fitting of the outcomes of a sequence of designed experiments. These last were executed by incubating stainless steel coupons carrying sessile bacteria, for 24 h, in 1:10 diluted tryptone soya broth, under 15 different combinations of three independent factors (T, pH and NaCl). For each strain, a second order polynomial model, describing the relationship between biofilm formation (log CFU/cm 2 ) and the factors (T, pH and NaCl), was developed using least square regression analysis. Both derived models predicted the combined influences of these factors on biofilm formation, with agreement between predictions and experimental observations (R 2  ≥ 0.96, P ≤ 0.0001). For both strains, the increase of NaCl content restricted their sessile growth, while under low salinity conditions (NaCl formation was favored as pH increased, regardless of T. Interestingly, under low salt content, and depending on the strain, biofilm formation was either favored or hindered by increasing T. Thus, 34.5 and 13 °C were the T predicted to maximize biofilm formation by strains Enteritidis and Typhimurium, respectively, something which was also experimentally verified. To sum, these models can predict the interactive influences of crucial food-related factors on biofilm growth of a significant foodborne pathogen towards the efforts to limit its persistence in food industry. Copyright © 2018 Elsevier Ltd. All rights reserved.

  6. The flux pinning properties of BaSnO{sub 3}-added GdBa{sub 2}Cu3O{sub 7-δ} films with varying growth conditions

    Energy Technology Data Exchange (ETDEWEB)

    Lee, J. K.; Oh, J. Y.; Kang, B. [Dept. of Physics, Chungbuk National University, Cheongju (Korea, Republic of); Lee, J. M.; Kang, W. N. [Dept. of Physics, Sungkyunkwan University, Suwon (Korea, Republic of)

    2017-09-15

    Addition of BaSnO{sub 3} (BSO) to GdBa{sub 2}Cu{sub 3}O{sub 7-δ} (GdBCO) is reported to enhance the flux pinning property of GdBCO thick films. To investigate the effect of growth condition on the pinning properties, 700 nm-thick BSO-added GdBCO films deposited with varying temperatures and growth rates were prepared by using a pulsed laser deposition method. As the deposition temperature increases, the critical current density and the pinning force density show an improved field dependence up to 750 ℃ due to the increase in the formation of the a-axis growth and the BSO nanostructures. The films deposited at higher temperatures show degraded surfaces and as a result, degraded pinning behaviors. For the change in growth rate, the critical current density and the pinning force increase as the repetition rate increase at low magnetic fields, but this behavior is reversed in high magnetic fields. These results indicate that the film growth conditions significantly affect the formation of BSO nanostructures and the pinning properties of BSO-added GdBCO films.

  7. varying elastic parameters distributions

    KAUST Repository

    Moussawi, Ali

    2014-12-01

    The experimental identication of mechanical properties is crucial in mechanics for understanding material behavior and for the development of numerical models. Classical identi cation procedures employ standard shaped specimens, assume that the mechanical elds in the object are homogeneous, and recover global properties. Thus, multiple tests are required for full characterization of a heterogeneous object, leading to a time consuming and costly process. The development of non-contact, full- eld measurement techniques from which complex kinematic elds can be recorded has opened the door to a new way of thinking. From the identi cation point of view, suitable methods can be used to process these complex kinematic elds in order to recover multiple spatially varying parameters through one test or a few tests. The requirement is the development of identi cation techniques that can process these complex experimental data. This thesis introduces a novel identi cation technique called the constitutive compatibility method. The key idea is to de ne stresses as compatible with the observed kinematic eld through the chosen class of constitutive equation, making possible the uncoupling of the identi cation of stress from the identi cation of the material parameters. This uncoupling leads to parametrized solutions in cases where 5 the solution is non-unique (due to unknown traction boundary conditions) as demonstrated on 2D numerical examples. First the theory is outlined and the method is demonstrated in 2D applications. Second, the method is implemented within a domain decomposition framework in order to reduce the cost for processing very large problems. Finally, it is extended to 3D numerical examples. Promising results are shown for 2D and 3D problems.

  8. On-line monitoring of CO2 production in Lactococcus lactis during physiological pH decrease using membrane inlet mass spectrometry with dynamic pH calibration.

    Science.gov (United States)

    Andersen, Ann Zahle; Lauritsen, Frants Roager; Olsen, Lars Folke

    2005-12-20

    Monitoring CO2 production in systems, where pH is changing with time is hampered by the chemical behavior and pH-dependent volatility of this compound. In this article, we present the first method where the concentration and production rate of dissolved CO2 can be monitored directly, continuously, and quantitatively under conditions where pH changes rapidly ( approximately 2 units in 15 min). The method corrects membrane inlet mass spectrometry (MIMS) measurements of CO2 for pH dependency using on-line pH analysis and an experimentally established calibration model. It is valid within the pH range of 3.5 to 7, despite pH-dependent calibration constants that vary in a non-linear fashion with more than a factor of 3 in this interval. The method made it possible to determine the carbon dioxide production during Lactococcus lactis fermentations, where pH drops up to 3 units during the fermentation. The accuracy was approximately 5%. We used the method to investigate the effect of initial extracellular pH on carbon dioxide production during anarobic glucose fermentation by non-growing Lactocoocus lactis and demonstrated that the carbon dioxide production rate increases considerably, when the initial pH was increased from 6 to 6.8. (c) 2005 Wiley Periodicals, Inc.

  9. Efficacy of Neutral pH Electrolyzed Water in Reducing Escherichia coli O157:H7 and Salmonella Typhimurium DT 104 on Fresh Produce Items using an Automated Washer at Simulated Food Service Conditions.

    Science.gov (United States)

    Afari, George K; Hung, Yen-Con; King, Christopher H

    2015-08-01

    The objective of this study was to determine the efficacy of neutral pH electrolyzed (NEO) water (155 mg/L free chlorine, pH 7.5) in reducing Escherichia coli O157:H7 and Salmonella Typhimurium DT 104 on romaine lettuce, iceberg lettuce, and tomatoes washed in an automated produce washer for different times and washing speeds. Tomatoes and lettuce leaves were spot inoculated with 100 μL of a 5 strain cocktail mixture of either pathogen and washed with 10 or 8 L of NEO water, respectively. Washing lettuce for 30 min at 65 rpm led to the greatest reductions, with 4.2 and 5.9 log CFU/g reductions achieved for E. coli O157:H7 and S. Typhimurium respectively on romaine, whereas iceberg lettuce reductions were 3.2 and 4.6 log CFU/g for E. coli O157:H7 and S. Typhimurium respectively. Washing tomatoes for 10 min at 65 rpm achieved reductions greater than 8 and 6 log CFU/tomato on S. Typhimurium and E. coli O157:H7 respectively. All pathogens were completely inactivated in NEO water wash solutions. No detrimental effects on the visual quality of the produce studied were observed under all treatment conditions. Results show the adoption of this washing procedure in food service operations could be useful in ensuring produce safety. © 2015 Institute of Food Technologists®

  10. Effective degradation of rhodamine B by electro-Fenton process, using ferromagnetic nanoparticles loaded on modified graphite felt electrode as reusable catalyst: in neutral pH condition and without external aeration.

    Science.gov (United States)

    Tian, Jiangnan; Zhao, Jixiang; Olajuyin, Ayobami Matthew; Sharshar, Moustafa Mohamed; Mu, Tingzhen; Yang, Maohua; Xing, Jianmin

    2016-08-01

    Polytetrafluoroethylene/ferromagnetic nanoparticle/carbon black (PTFE/MNP/CB)-modified graphite felt (GF) was successfully applied as cathode for the mineralization of rhodamine B (RhB) in electro-Fenton (EF) process. The modified cathode showed high decolorization efficiency for RhB solution even in neutral pH condition and without external aeration, achieving nearly complete decolorization and 89.52 % total organic carbon (TOC) removal after 270-min oxidation with the MNP load 1.2 g at 50 A/m(2). Moreover, the operational parameters (current density, MNP load, initial pH, and airflow rate) were optimized. After that, adsorption isotherm was also conducted to compare the absorption quantity of CB and carbon nanotube (CNT). Then, the surface morphologies of MNPs were characterized by transmission electron microscope (TEM), energy-dispersive X-ray detector (EDX), and Fourier transform infrared spectroscopy (FTIR); and the modified cathode was characterized by SEM and contact angle. Finally, the stability and reusability of modified cathode were tested. Result uncovered that the PTFE/MNP/CB-modified cathode has the potential for industrial application and the solution after treatment was easily biodegradable.

  11. Evaluation des performances de la production de graines par tamisage manuel du sol chez trois variétés de Stylosanthes guianensis (Aublet Swartz, dans les conditions du Plateau des Batéké (RDC

    Directory of Open Access Journals (Sweden)

    Bulakali, BP.

    2013-01-01

    Full Text Available Performance Assessment of the Production of Seeds by Manual Sieving of the Soil of Three Varieties of Stylosanthes guianensis (Aublet Swartz under the Conditions of the Batéké Plateau (DRC. In manual agriculture with low resources level, Stylosanthes guianensis is one of the most interesting cover crop for developing direct seeding mulch-based cropping systems. To promote its cultivation in the DRC, the performances of a seed production method by sieving of the soil were evaluated for three varieties of Stylo (a local ecotype, CIAT 184 variety, and 202cc variety in two sites of the Batéké plateau characterized by contrasted fertility levels. The results obtained demonstrate the interest of the seed multiplication method tested, both in quantities and quality of the produced seeds. The production cost of one kg of seeds varies with the soil fertility, the planting date, and the cultivar. Among the three compared varieties, CIAT 184 variety produced the highest quantity of seeds. If sown at the beginning of the long rainy season, after a long fallow, in one of the most fertile soils of the plateau, this cultivar can produce 600 kg ha-1 seed in the first year of cultivation with a production cost of USD 1.31 kg-1, equivalent to less than 0.5 man.day.kg-1.

  12. Surface activity evaluation of an arabinose ester as water/oil demulsifier at severe conditions of temperature, salinity and pH; Avaliacao da atividade superficial de um ester de arabinose, como desemulsificante agua/oleo, em condicoes severas de temperatura, salinidade e pH

    Energy Technology Data Exchange (ETDEWEB)

    Borges, Mauricio Rodrigues; Garcia, Rosangela Balaban; Santos, Jaciara Alves dos; Vieira, Mariane; Silva, Luciana Carvalho; Campos, Viviane de Oliveira; Silva, Rayane Araujo da; Santos, Telma Pitanga dos [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil)

    2008-07-01

    This work had for objective to compare the superficial properties of an arabinose ester, no-ionic, nontoxic, biodegradable, with two commercial products: the first one based on sodium dodecyl sulfate and the second one based on poly-oxy alkylene phenol formaldehyde. The arabinose ester was synthesized on the Petroleum Research Laboratory - UFRN, through enzymatic catalysis by protease from Bacillus subtilis, using arabinose and vegetable oil, in organic medium. In previous work [1], this sugar ester was evaluated as a possible water/oil demulsifier and the results were compared with the results of the commercial product based on poly-oxy alkylene phenol formaldehyde, showing that, for certain reaction conditions, the sugar ester presented better acting (71%) that the commercial product (33%) as demulsifier. In this work, the stability of this arabinose ester was evaluated in severe conditions of temperature, salinity and pH, through superficial tests in a tensiometer, using Wilhelmy plate method and the results were compared with the results obtained for two commercial products above mentioned. (author)

  13. Condições de pH e temperatura para máxima atividade da bromelina do abacaxi (Ananas Comosus L. Merril = Temperature and pH conditions for maximum activity of bromelain extracted from pineapple (Ananas Comosus L. Merril

    Directory of Open Access Journals (Sweden)

    Moacyr Jorge Elias

    2011-04-01

    Full Text Available A bromelina, enzima presente no abacaxi, hidrolisa ligações peptídicas das proteínas; tem aplicação em diversas áreas envolvendo alimentos e medicina. Visando o aproveitamento da bromelina recuperada, a partir dos resíduos da industrialização do fruto(variedade pérola, foram pesquisadas condições de pH e temperatura para maior atividade, empregando caseína como substrato. O extrato foi obtido pela trituração da casca e do talo interno do fruto. A atividade foi expressa em mmol tirosina L-1 min.-1 pela absorbância a280 nm dos aminoácidos aromáticos gerados na hidrólise da caseína. Os ensaios foram efetuados em duplicata para duas relações enzima/substrato: 1/25 e 1/125 (em massa. Foi estabelecido um planejamento experimental em estrela tendo como ponto central pH em7,0 e temperatura de 35°C. Os resultados foram tratados empregando o aplicativo computacional MINITAB 15 da Minitab Inc. que forneceu as equações do modelo e as superfícies de resposta. As equações foram tratadas matematicamente (cálculo diferencial, fornecendo gráficos da melhor atividade em função da temperatura. Observou-se perda daatividade enzimática com a elevação da temperatura para relação 1/25, atribuída à maior presença de enzima livre em comparação com a relação 1/125.Bromelain, the enzyme found in pineapple, hydrolyzes proteins’ peptide bonds, has several applications in the food industry and in medicine. Temperature and pH conditions for highest activity with casein as substrate were investigated from the bromelain recovered from industrialized pineapple (‘pérola’ variety fruit residues. Extract was obtained by grinding fruit rind and its internal stem. The activity was expressed in mmol tyrosine L-1 min.-1 by absorbance at 280 nm of aromatic amino acids produced in casein hydrolysis. Assays were undertaken in duplicate for two enzyme/substrate with ratios: 1/25 and 1/125 (mass. Eight-pointed experimental design was

  14. Time-varying BRDFs.

    Science.gov (United States)

    Sun, Bo; Sunkavalli, Kalyan; Ramamoorthi, Ravi; Belhumeur, Peter N; Nayar, Shree K

    2007-01-01

    The properties of virtually all real-world materials change with time, causing their bidirectional reflectance distribution functions (BRDFs) to be time varying. However, none of the existing BRDF models and databases take time variation into consideration; they represent the appearance of a material at a single time instance. In this paper, we address the acquisition, analysis, modeling, and rendering of a wide range of time-varying BRDFs (TVBRDFs). We have developed an acquisition system that is capable of sampling a material's BRDF at multiple time instances, with each time sample acquired within 36 sec. We have used this acquisition system to measure the BRDFs of a wide range of time-varying phenomena, which include the drying of various types of paints (watercolor, spray, and oil), the drying of wet rough surfaces (cement, plaster, and fabrics), the accumulation of dusts (household and joint compound) on surfaces, and the melting of materials (chocolate). Analytic BRDF functions are fit to these measurements and the model parameters' variations with time are analyzed. Each category exhibits interesting and sometimes nonintuitive parameter trends. These parameter trends are then used to develop analytic TVBRDF models. The analytic TVBRDF models enable us to apply effects such as paint drying and dust accumulation to arbitrary surfaces and novel materials.

  15. Biotite and chlorite weathering at 25 degrees C: the dependence of pH and (bi)carbonate on weathering kinetics, dissolution stoichiometry, and solubility; and the relation to redox conditions in granitic aquifers

    International Nuclear Information System (INIS)

    Malmstroem, M.; Banwart, S.

    1995-01-01

    We have studied the kinetics and thermodynamics of biotite and chlorite weathering in the pH range 2 2 -10 2 year); and 2. the development of characteristic Fe(III) concentrations (10 -5 M in 10 - 1 years). The Fe(III)-bearing clay minerals formed during these experiments are similar to the fracture-filling-material observed at the Aespoe Hard Rock Laboratory. Such clays can provide reducing capacity to a repository. They can help maintain anoxic conditions by consuming oxygen that enters the repository during the construction and operation phases thereby helping maintain the redox stability of the repository regarding canister corrosion. The half-life of oxygen trapped in the repository at the time of closure depends on the rate of oxygen uptake by Fe(II) minerals, sulfide minerals and organic carbon. Fe(II)-clay minerals are important to the redox stability of a repository, as well as providing a sorption barrier to radionuclide migration. 107 refs, 52 figs, 35 tabs

  16. The influence of pH adjustment on kinetics parameters in tapioca wastewater treatment using aerobic sequencing batch reactor system

    Science.gov (United States)

    Mulyani, Happy; Budianto, Gregorius Prima Indra; Margono, Kaavessina, Mujtahid

    2018-02-01

    The present investigation deals with the aerobic sequencing batch reactor system of tapioca wastewater treatment with varying pH influent conditions. This project was carried out to evaluate the effect of pH on kinetics parameters of system. It was done by operating aerobic sequencing batch reactor system during 8 hours in many tapioca wastewater conditions (pH 4.91, pH 7, pH 8). The Chemical Oxygen Demand (COD) and Mixed Liquor Volatile Suspended Solids (MLVSS) of the aerobic sequencing batch reactor system effluent at steady state condition were determined at interval time of two hours to generate data for substrate inhibition kinetics parameters. Values of the kinetics constants were determined using Monod and Andrews models. There was no inhibition constant (Ki) detected in all process variation of aerobic sequencing batch reactor system for tapioca wastewater treatment in this study. Furthermore, pH 8 was selected as the preferred aerobic sequencing batch reactor system condition in those ranging pH investigated due to its achievement of values of kinetics parameters such µmax = 0.010457/hour and Ks = 255.0664 mg/L COD.

  17. Detection of dynamically varying interaural time differences

    DEFF Research Database (Denmark)

    Kohlrausch, Armin; Le Goff, Nicolas; Breebaart, Jeroen

    2010-01-01

    of fringes surrounding the probe is equal to the addition of the effects of the individual fringes. In this contribution, we present behavioral data for the same experimental condition, called dynamically varying ITD detection, but for a wider range of probe and fringe durations. Probe durations varied...

  18. Influence of pH on extracellular matrix preservation during lung decellularization.

    Science.gov (United States)

    Tsuchiya, Tomoshi; Balestrini, Jenna L; Mendez, Julio; Calle, Elizabeth A; Zhao, Liping; Niklason, Laura E

    2014-12-01

    The creation of decellularized organs for use in regenerative medicine requires the preservation of the organ extracellular matrix (ECM) as a means to provide critical cues for differentiation and migration of cells that are seeded onto the organ scaffold. The purpose of this study was to assess the influence of varying pH levels on the preservation of key ECM components during the decellularization of rat lungs. Herein, we show that the pH of the 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate (CHAPS)-based decellularization solution influences ECM retention, cell removal, and also the potential for host response upon implantation of acellular lung tissue. The preservation of ECM components, including elastin, fibronectin, and laminin, were better retained in the lower pH conditions that were tested (pH ranges tested: 8, 10, 12); glycosaminoglycans were preserved to a higher extent in the lower pH groups as well. The DNA content following decellularization of the rat lung was inversely correlated with the pH of the decellularization solution. Despite detectible levels of cyotoskeletal proteins and significant residual DNA, tissues decellularized at pH 8 demonstrated the greatest tissue architecture maintenance and the least induction of host response of all acellular conditions. These results highlight the effect of pH on the results obtained by organ decellularization and suggest that altering the pH of the solutions used for decellularization may influence the ability of cells to properly differentiate and home to appropriate locations within the scaffold, based on the preservation of key ECM components and implantation results.

  19. Formation of M-Like Intermediates in Proteorhodopsin in Alkali Solutions (pH ≥ ∼8.5) Where the Proton Release Occurs First in Contrast to the Sequence at Lower pH.

    Science.gov (United States)

    Tamogami, Jun; Sato, Keitaro; Kurokawa, Sukuna; Yamada, Takumi; Nara, Toshifumi; Demura, Makoto; Miyauchi, Seiji; Kikukawa, Takashi; Muneyuki, Eiro; Kamo, Naoki

    2016-02-23

    Proteorhodopsin (PR) is an outward light-driven proton pump observed in marine eubacteria. Despite many structural and functional similarities to bacteriorhodopsin (BR) in archaea, which also acts as an outward proton pump, the mechanism of the photoinduced proton release and uptake is different between two H(+)-pumps. In this study, we investigated the pH dependence of the photocycle and proton transfer in PR reconstituted with the phospholipid membrane under alkaline conditions. Under these conditions, as the medium pH increased, a blue-shifted photoproduct (defined as Ma), which is different from M, with a pKa of ca. 9.2 was produced. The sequence of the photoinduced proton uptake and release during the photocycle was inverted with the increase in pH. A pKa value of ca. 9.5 was estimated for this inversion and was in good agreement with the pKa value of the formation of Ma (∼ 9.2). In addition, we measured the photoelectric current generated by PRs attached to a thin polymer film at varying pH. Interestingly, increases in the medium pH evoked bidirectional photocurrents, which may imply a possible reversal of the direction of the proton movement at alkaline pH. On the basis of these findings, a putative photocycle and proton transfer scheme in PR under alkaline pH conditions was proposed.

  20. Corrosion fatigue investigation of a high nitrogen 12% Cr-steel and of a high strength martensitic PH 13-8 Mo steel under simulated steam turbine conditions. Final report

    International Nuclear Information System (INIS)

    Schmitt-Thomas, K.G.; Schweigart, H.

    1992-01-01

    This report summarizes the results of the corrosion fatigue investigations of two martensitic stainless steels (PH 13-8 Mo, X20 CrMoV 12 1; corrosion medium: 0,01 m NaCl or 22 wt% NaCl; pH value 3 or 7). The working programm includes electrochemical and corrosion fatigue tests. Also chemical analysis, mechanical-technological and metallographical as SEM investigations were performed. (orig.)

  1. PH og modernismen

    DEFF Research Database (Denmark)

    Ahnfeldt-Mollerup, Merete

    2012-01-01

    Artiklen kaster et kritisk blik på Poul Henningsens samfundsanalyse og dennes sammenhæng med hans design. PH ses i en bredere national og international sammenhæng. Diskussion af designmetoder, æstetik og Bauhaus.......Artiklen kaster et kritisk blik på Poul Henningsens samfundsanalyse og dennes sammenhæng med hans design. PH ses i en bredere national og international sammenhæng. Diskussion af designmetoder, æstetik og Bauhaus....

  2. Relación entre la variación de las condiciones ambientales y la temperatura interna de la yema del manzano 'Anna' Inner bud temperature of' Anna' apple trees in relation to varying environmental conditions

    Directory of Open Access Journals (Sweden)

    Casierra Posada Fannor

    2001-12-01

    Full Text Available En Paipa (Colombia, se realizó un ensayo de campo con el fin de determinar el efecto de la variación de las condiciones ambientales sobre la temperatura interna de la yema del manzano 'Anna' cultivado en condiciones de altiplano tropical. Los registros se hicieron en un árbol de cuatro años, el cual se defolió manualmente y se podó pocas semanas después de la cosecha. Se midió la temperatura del aire y se comparó con la temperatura de una yema en el árbol. Para medir la temperatura de la yema se colocó un sensor digital muy delgado entre los catáfilos de la yema; la temperatura ambiente se registró con un termómetro de bulbo. Las mediciones se realizaron cada media hora entre las 7:00 y las 17:30 horas del día, durante 19 días, empezando el día en que el árbol fue defoliado hasta cuando la yema alcanzó el estado fenológico "green tip". Al tiempo con cada medición de temperatura se registró el fenómeno climático más sobresaliente (lluvia, tiempo soleado, viento, tiempo nublado, etc. y los datos se agruparon según cada fenómeno climático. Los resultados mostraron que la yema presentó una temperatura 1,49°C por encima de la temperatura del aire durante el transcurso del día, en la noche no hubo diferencia de temperatura. En condiciones de lluvia, la temperatura
    de la yema estuvo 0,57°C por encima de la temperatura
    del aire. Bajo cielo nublado la yema estuvo 0,56°C más cálida
    que el aire. En condiciones de viento la yema presentó una
    diferencia de 0,87°C sobre la temperatura del aire. En días
    soleados, la yema mantuvo una temperatura 2,3°C sobre la temperatura del aire. Las diferencias entre la temperatura del aire y la de la yema se discuten con base en la transpiración, la convección y la radiación.A field experiment was conducted in Paipa (Colombia to study the effect of environmental varying over inner bud temperature of an 'Anna' apple tree 4 years old growing in tropical

  3. Spectroscopic determination of pH

    International Nuclear Information System (INIS)

    Faanu, A.; Glover, E.T.; Bailey, E.; Rochelle, C.

    2009-01-01

    A technique of measuring pH at temperature range of 20 - 70 0 C and high pressure conditions of 1 - 200 atmospheres has been developed by relating the ratio of absorbance peaks of indicator solutions (basic and acidic) as a function of pH, using ultraviolet-visible spectrophotometer. The pH values of the buffer solutions measured at 20 0 C and 70 0 C indicated slight temperature dependence, while the pressure had no effect. The pH of the buffer solutions increased with temperature with relative standard deviations in the range 0.4 - 0.5 % at 95 % confidence interval. The possible causes of the temperature dependence were attributed to changes in pH values as the temperature changed. (au)

  4. How fields vary.

    Science.gov (United States)

    Krause, Monika

    2018-03-01

    Field theorists have long insisted that research needs to pay attention to the particular properties of each field studied. But while much field-theoretical research is comparative, either explicitly or implicitly, scholars have only begun to develop the language for describing the dimensions along which fields can be similar to and different from each other. In this context, this paper articulates an agenda for the analysis of variable properties of fields. It discusses variation in the degree but also in the kind of field autonomy. It discusses different dimensions of variation in field structure: fields can be more or less contested, and more or less hierarchical. The structure of symbolic oppositions in a field may take different forms. Lastly, it analyses the dimensions of variation highlighted by research on fields on the sub- and transnational scale. Post-national analysis allows us to ask how fields relate to fields of the same kind on different scales, and how fields relate to fields on the same scale in other national contexts. It allows us to ask about the role resources from other scales play in structuring symbolic oppositions within fields. A more fine-tuned vocabulary for field variation can help us better describe particular fields and it is a precondition for generating hypotheses about the conditions under which we can expect to observe fields with specified characteristics. © London School of Economics and Political Science 2017.

  5. Salivary pH: A diagnostic biomarker

    Directory of Open Access Journals (Sweden)

    Sharmila Baliga

    2013-01-01

    Full Text Available Objectives: Saliva contains a variety of host defense factors. It influences calculus formation and periodontal disease. Different studies have been done to find exact correlation of salivary biomarkers with periodontal disease. With a multitude of biomarkers and complexities in their determination, the salivary pH may be tried to be used as a quick chairside test. The aim of this study was to analyze the pH of saliva and determine its relevance to the severity of periodontal disease. Study Design: The study population consisted of 300 patients. They were divided into three groups of 100 patients each: Group A had clinically healthy gingiva, Group B who had generalized chronic gingivitis and Group C who had generalized chronic periodontitis. The randomized unstimulated saliva from each patient was collected and pH was tested. Data was analyzed statistically using analysis of variance technique. Results: The salivary pH was more alkaline for patients with generalized chronic gingivitis as compared with the control group (P = 0.001 whereas patients with generalized chronic periodontitis had more acidic pH as compared with the control group (P = 0.001. Conclusion: These results indicate a significant change in the pH depending on the severity of the periodontal condition. The salivary pH shows significant changes and thus relevance to the severity of periodontal disease. Salivary pH may thus be used as a quick chairside diagnostic biomarker.

  6. Salivary pH: A diagnostic biomarker.

    Science.gov (United States)

    Baliga, Sharmila; Muglikar, Sangeeta; Kale, Rahul

    2013-07-01

    Saliva contains a variety of host defense factors. It influences calculus formation and periodontal disease. Different studies have been done to find exact correlation of salivary biomarkers with periodontal disease. With a multitude of biomarkers and complexities in their determination, the salivary pH may be tried to be used as a quick chairside test. The aim of this study was to analyze the pH of saliva and determine its relevance to the severity of periodontal disease. The study population consisted of 300 patients. They were divided into three groups of 100 patients each: Group A had clinically healthy gingiva, Group B who had generalized chronic gingivitis and Group C who had generalized chronic periodontitis. The randomized unstimulated saliva from each patient was collected and pH was tested. Data was analyzed statistically using analysis of variance technique. The salivary pH was more alkaline for patients with generalized chronic gingivitis as compared with the control group (P = 0.001) whereas patients with generalized chronic periodontitis had more acidic pH as compared with the control group (P = 0.001). These results indicate a significant change in the pH depending on the severity of the periodontal condition. The salivary pH shows significant changes and thus relevance to the severity of periodontal disease. Salivary pH may thus be used as a quick chairside diagnostic biomarker.

  7. Effect of pH on the toxicity and bioconcentration of sulfadiazine on Daphnia magna

    DEFF Research Database (Denmark)

    Anskjær, Gitte Gotholdt; Rendal, Cecilie; Kusk, Kresten Ole

    2013-01-01

    The antimicrobial sulfonamide sulfadiazine has in the last decades been detected in environmental water bodies, both surface and ground water. Since pH in the environment may vary considerably, this study examined the toxicity of the amphoter sulfadiazine towards Daphnia magna at pH levels of 6.......0, 7.5 and 8.5, thus taking the impact of speciation into consideration, contrary to earlier eco-toxicity studies conducted at standard conditions. Toxicity tests were performed using the standard ISO 6341 test procedure modified to accommodate the three pH levels and the toxicity was expressed as EC50....... After 48h the EC50 was determined to be 27.2, 188 and 310mgL−1 at pH 6.0, 7.5 and 8.5, respectively, thus demonstrating a significant effect of pH on the toxicity of sulfadiazine. Furthermore, the bioconcentration factor (dry weight) was determined to be 50 and 36 at pH 6.0 and 8.5, respectively...

  8. Plant Habitat (PH)

    Science.gov (United States)

    Onate, Bryan

    2016-01-01

    The International Space Station (ISS) will soon have a platform for conducting fundamental research of Large Plants. Plant Habitat (PH) is designed to be a fully controllable environment for high-quality plant physiological research. PH will control light quality, level, and timing, temperature, CO2, relative humidity, and irrigation, while scrubbing ethylene. Additional capabilities include leaf temperature and root zone moisture and oxygen sensing. The light cap will have red (630 nm), blue (450 nm), green (525 nm), far red (730 nm) and broad spectrum white LEDs. There will be several internal cameras (visible and IR) to monitor and record plant growth and operations.

  9. Inhibitors of acid secretion can benefit gastric wound repair independent of luminal pH effects on the site of damage

    Science.gov (United States)

    Demitrack, Elise S; Aihara, Eitaro; Kenny, Susan; Varro, Andrea; Montrose, Marshall H

    2012-01-01

    Background and aims The authors’ goal was to measure pH at the gastric surface (pHo) to understand how acid secretion affects the repair of microscopic injury to the gastric epithelium. Methods Microscopic gastric damage was induced by laser light, during confocal/two-photon imaging of pH-sensitive dyes (Cl-NERF, BCECF) that were superfused over the mucosal surface of the exposed gastric corpus of anaesthetised mice. The progression of repair was measured in parallel with pHo. Experimental conditions included varying pH of luminal superfusates, and using omeprazole (60 mg/kg ip) or famotidine (30 mg/kg ip) to inhibit acid secretion. Results Similar rates of epithelial repair and resting pHo values (~pH 4) were reported in the presence of luminal pH 3 or pH 5. Epithelial repair was unreliable at luminal pH 2 and pHo was lower (2.5±0.2, P pH 3). Epithelial repair was slower at luminal pH 7 and pHo was higher (6.4±0.1, PpH 3 or pH 7, omeprazole reduced maximal damage size and accelerated epithelial repair, although only at pH 3 did omeprazole further increase surface pH above the level caused by imposed damage. At luminal pH 7, famotidine also reduced maximal damage size and accelerated epithelial repair. Neither famotidine nor omeprazole raised plasma gastrin levels during the time course of the experiments. Conclusions Epithelial repair in vivo is affected by luminal pH variation, but the beneficial effects of acutely blocking acid secretion extend beyond simply raising luminal and/or surface pH. PMID:21997560

  10. Effect of pH value on electromagnetic loss properties of Co–Zn ferrite prepared via coprecipitation method

    International Nuclear Information System (INIS)

    Huang, Xiaogu; Zhang, Jing; Wang, Wei; Sang, Tianyi; Song, Bo; Zhu, Hongli; Rao, Weifeng; Wong, Chingping

    2016-01-01

    In this paper, the cobalt zinc ferrite was prepared by coprecipitation method at different pH conditions. The influence of pH values on the coprecipitation reaction was theoretically analyzed at first. The calculated results showed that the pH values should be controlled in the range of 9–11 to form the stable precipitation. The XRD investigation was used to further confirm the formation of the composite on specific pH values. In addition, the morphological study revealed that the average particle size of the composite decreased from 40 nm to 30 nm when the pH value increased from 9–11. The variation of microstructure plays a critical role in controlling the electromagnetic properties. From the electromagnetic analysis, the dielectric loss factor was 0.02–0.07 and magnetic loss factor was 0.2–0.5 for the composite synthesized at pH of 9, which presents dramatically improved dielectric loss and magnetic loss properties than the samples prepared at pH of 10 and 11. The as-prepared cobalt zinc ferrite are highly promising to be used as microwave absorption materials. - Highlights: • Co–Zn ferrite was prepared by coprecipitation method with different pH values. • To obtain pure Co–Zn ferrite, the theoretical pH values were 9–11. • Microstructure and electromagnetic properties can be tuned by varying pH values. • Co–Zn ferrite prepared with pH=9 performed well electromagnetic loss properties.

  11. Towards an improved understanding of hillslope runoff as a supply for groundwater recharge: Assessing hillslope runoff under regional deforestation and varying climate conditions in a drainage basin in central coastal California

    Science.gov (United States)

    Young, K. S.; Beganskas, S.; Fisher, A. T.

    2017-12-01

    We use a hydrologic model to analyze hillslope runoff under a range of climate and land use conditions in the San Lorenzo River Basin (SLRB), central coastal California, including contemporary land use and incremental deforestation. The SLRB is a heavily forested watershed with chronically overdrafted aquifers; in some areas, groundwater levels have been lowered by >50 m in recent decades. Managed aquifer recharge (MAR) can help mitigate declines in groundwater storage, routing excess surface flows to locations where they can infiltrate. We are especially interested in opportunities for collection of stormwater runoff, particularly where development and other changes in landuse have increased hill slope runoff. To assess hillslope runoff at the subwatershed scale (10-100 ha; 25-250 ac), we apply the Precipitation Runoff Modeling System (PRMS) to a high-resolution, digital elevation model and populate the simulation with area- and density-weighted vegetation and soil parameters calculated from high resolution input data. We also develop and apply a catalog of dry, normal, and wet climate scenarios from the historic record (1981-2014). In addition, we simulate conditions ranging from 0 to 100 percent of redwoods harvested (representing the mid-1800s to 1930s logging era) using a historical land use data set to alter soil and vegetation conditions. Results under contemporary land use suggest there are ample opportunities to establish MAR projects during all climate scenarios; hill slope runoff generation is spatially variable and on average exceeds 23,000 ac-ft/yr (3.2 in/yr) during the driest climate scenario. Preliminary results from the deforestation scenarios show notable increases in hillslope runoff with progressive redwood harvesting. Relative to pre-logging conditions, between 1.1 in (dry climates) and 1.5 in (wet climates) more runoff is generated under contemporary conditions, with most of the runoff increase occurring in urban areas. These modeling methods

  12. Productivity of seed agrocenosis of common millet (Panicum miliaceum L. at varying so­ ing w terms and techniques under the conditions of Right- Bank Forest-Steppe

    Directory of Open Access Journals (Sweden)

    С. П. Полторецький

    2013-08-01

    Full Text Available The objective of the research is to improve the techno­logy of growing high-quality seeds of millet broomcorn by means of the optimization of sowing terms and methods, aimed at increasing its productivity and improving seed qualities under conditions of unstable moistening of the Right-Bank Forest-Steppe of Ukraine. Scientific literature review indicates the study of the influence of these technology elements on the formation of sowing qualities and crop capacity of millet seeds has been of schematic and occasional nature. The issue has not been studied in this region condition at all, that is why the research has considerable significance and novelty. Analysis, observations and calculations were done by means of conventional methods. Research results indicate that under conditions of unstable moistening of the southern part of the Right-Bank Forest-Steppe of Ukraine the highest yield of Slobozhanske and Lana varieties was reached at sowing in drills – 39.2 and 41.0 metric centners per hectare, respectively. That was 2.4 and 3.9 metric centners per hectare increase against the wide-row sowing. In the years with optimal hydrothermal conditions maximum seed productivity of millet broomcorn at the level of 4.24 to 4.79 metric tons per hectare (Slobozhanske variety and 4.53 to 5.28 metric tons per hectare (Lana variety was observed at postponing the sowing terms to the third decade of May. If atypical for the region hydrothermal conditions (drought or excessive moistening are forecasted du­ ring the vegetation period of millet, the highest productivity is provided by sowing in the second decade of May. Early sowing in the first decade of May causes decrease in yield at the level of 0.14 to 0.48 metric tons per hectare (Slobozhanske variety and 0.14 to 0.48 metric tons per hectare (Lana variety; if the sowing is postponed to the first decade of June, the yield increases by 0.31 to 0.77 and 0.39 to 0.84 metric tons per hectare, respectively. Early

  13. The isotopic composition of valves and organic tissue of diatoms grown in steady state cultures under varying conditions of temperature, light and nutrients. Implications for the interpretation of oxygen isotopes from sedimentary biogenic opal as proxies of environmental variations

    Energy Technology Data Exchange (ETDEWEB)

    Kowalczyk, K

    2006-05-15

    The oxygen isotopes of diatomaceous silica from marine and freshwater sediments are frequently used as indicators of the palaeotemperature development, particularly in cases where calcareous microfossils are rare or absent. With regard to terrestrial waters it is unknown whether or not palaeotemperature scale can be used in a limnic ecosystem. Due to the fact that the seasonal variations in lakes are larger than in oceans, specific problems arise when working with freshwater sediments. Thus, an understanding of the contribution of the various factors (e.g. temperature, light nutrients, competition) influencing the formation of isotope signals in biogenic opal is a prerequisite for the accurate interpretation of environmental processes. Since it is impossible to examine the influence of a single parameter under natural ecosystem conditions due to permanent changes of the environment, laboratory experiments with single diatom species are needed. Therefore, the aim of this study was to investigate the correlation between the oxygen isotope variations in biogenic opal and different environmental parameters using steady state cultures with diatoms. It should be examined whether or not the different diatom species grown under identical conditions show equal oxygen isotope ratios (species relationship), if variations of the water temperature induce variations of the oxygen isotope ratio (relationship with temperature), variable parameters such as light intensity and nitrate concentration influence the isotope ratio, and if vital effects (e.g. growth rate) lead to variations of the oxygen isotope ratio. (orig.)

  14. The isotopic composition of valves and organic tissue of diatoms grown in steady state cultures under varying conditions of temperature, light and nutrients. Implications for the interpretation of oxygen isotopes from sedimentary biogenic opal as proxies of environmental variations

    International Nuclear Information System (INIS)

    Kowalczyk, K.

    2006-05-01

    The oxygen isotopes of diatomaceous silica from marine and freshwater sediments are frequently used as indicators of the palaeotemperature development, particularly in cases where calcareous microfossils are rare or absent. With regard to terrestrial waters it is unknown whether or not palaeotemperature scale can be used in a limnic ecosystem. Due to the fact that the seasonal variations in lakes are larger than in oceans, specific problems arise when working with freshwater sediments. Thus, an understanding of the contribution of the various factors (e.g. temperature, light nutrients, competition) influencing the formation of isotope signals in biogenic opal is a prerequisite for the accurate interpretation of environmental processes. Since it is impossible to examine the influence of a single parameter under natural ecosystem conditions due to permanent changes of the environment, laboratory experiments with single diatom species are needed. Therefore, the aim of this study was to investigate the correlation between the oxygen isotope variations in biogenic opal and different environmental parameters using steady state cultures with diatoms. It should be examined whether or not the different diatom species grown under identical conditions show equal oxygen isotope ratios (species relationship), if variations of the water temperature induce variations of the oxygen isotope ratio (relationship with temperature), variable parameters such as light intensity and nitrate concentration influence the isotope ratio, and if vital effects (e.g. growth rate) lead to variations of the oxygen isotope ratio. (orig.)

  15. Fluctuation of Dof1/Dof2 expression ratio under the influence of varying nitrogen and light conditions: involvement in differential regulation of nitrogen metabolism in two genotypes of finger millet (Eleusine coracana L.).

    Science.gov (United States)

    Gupta, Supriya; Gupta, Sanjay Mohan; Gupta, Alok Kumar; Gaur, Vikram Singh; Kumar, Anil

    2014-08-10

    In order to gain insights into the mechanism of high nitrogen use efficiency (NUE) of finger millet (FM) the role of Dof2 transcription factor (TF), which is a repressor of genes involved in C/N metabolism was investigated. The partial cDNA fragment of EcDof2 (912-bp; GenBank acc. no. KF261117) was isolated and characterized from finger millet (FM) that showed 63% and 58% homology with Dof2 of Zea mays at nucleotide and protein level, respectively. Its expression studies were carried out along with the activator EcDof1 in two genotypes (GE3885, high protein genotype (HPG); GE1437, low protein genotype (LPG)) of FM differing in grain protein contents (13.8% and 6.2%) showed that EcDof2 is expressed in both shoot and root tissues with significantly (p≤0.05) higher expression in the roots. The diurnal expression of both EcDof1 and EcDof2 in shoots was differential having different time of peak expression indicating a differential response to diurnal condition. Under continuous dark conditions, expression of EcDof1 and EcDof2 oscillated in both the genotypes whereas on illumination, the fold expression of EcDof1 was higher as compared to EcDof2. Under increasing nitrate concentration, EcDof2 expression increases in roots and shoots of LPG while it remains unchanged in HPG. However, the EcDof1 expression was found to increase in both genotypes. Further, time kinetics studies under single nitrate concentration revealed that EcDof2 was repressed in the roots of both genotypes whereas EcDof1 oscillated with time. The EcDof1/EcDof2 ratio measured showed differential response under different light and nitrogen conditions. It was higher in the roots of HPG indicating higher activation of genes involved in N uptake and assimilation resulting in high grain protein accumulation. The results indicate that both light and nitrogen concentration influence Dof1 and Dof2 expression and suggests a complex pattern of regulation of genes influenced by these plant specific TFs. In

  16. The PhD by Publication

    Directory of Open Access Journals (Sweden)

    Susi Peacock

    2017-07-01

    Full Text Available Aim/Purpose: The purpose of this work is to develop more nuanced understandings of the PhD by publication, particularly raising awareness of the retrospective PhD by publication. The article aims to contribute to contemporary debates about the differing pathways to the attainment of doctoral study completion and the artifacts submitted for that purpose. It also seeks to support prospective graduate students and supervisors who are embarking upon alternative routes to doctoral accreditation. Background: The PhD is considered the pinnacle of academic study – highly cherished, and replete with deeply held beliefs. In response to changes in job markets, developments in the disciplines, and more varied student cohorts, diverse pathways to completion of this award have emerged, such as the PhD by publication (PhDP. A PhDP may either be prospective or retrospective. For the former, publications are planned and created with their contributions to the PhDP in mind. The retrospective PhD is assembled after some, or most, of the publications have been completed. The artifact submitted for examination in this case consists of a series of peer-reviewed academic papers, books, chapters, or equivalents that have been published or accepted for publication, accompanied by an over-arching narrative. The retrospective route is particularly attractive for professionals who are research-active but lack formal academic accreditation at the highest level. Methodology: This article calls upon a literature review pertaining to the award of PhDP combined with the work of authors who offer their personal experiences of the award. The author also refers to her candidature as a Scottish doctoral student whilst studying for the award of PhD by publication. Contribution: This work raises awareness of the PhDP as a credible and comparable pathway for graduate students. The article focuses upon the retrospective PhDP which, as with all routes to doctoral accreditation, has

  17. Ellipsometry with randomly varying polarization states

    NARCIS (Netherlands)

    Liu, F.; Lee, C. J.; Chen, J. Q.; E. Louis,; van der Slot, P. J. M.; Boller, K. J.; F. Bijkerk,

    2012-01-01

    We show that, under the right conditions, one can make highly accurate polarization-based measurements without knowing the absolute polarization state of the probing light field. It is shown that light, passed through a randomly varying birefringent material has a well-defined orbit on the Poincar

  18. Low pH Cements

    International Nuclear Information System (INIS)

    Savage, David; Benbow, Steven

    2007-05-01

    The development of low-pH cements for use in geological repositories for radioactive waste stems from concerns over the potential for deleterious effects upon the host rock and other EBS materials (notably bentonite) under the hyperalkaline conditions (pH > 12) of cement pore fluids. Low pH cement (also known as low heat cement) was developed by the cement industry for use where large masses of cement (e.g. dams) could cause problems regarding heat generated during curing. In low pH cements, the amount of cement is reduced by substitution of materials such as fly ash, blast furnace slag, silica fume, and/or non-pozzolanic silica flour. SKB and Posiva have ruled out the use of blast furnace slag and fly-ash and are focusing on silica fume as a blending agent. Currently, no preferred composition has been identified by these agencies. SKB and Posiva have defined a pH limit ≤ 11 for cement grout leachates. To attain this pH, blending agents must comprise at least 50 wt % of dry materials. Because low pH cement has little, or no free portlandite, the cement consists predominantly of calcium silicate hydrate (CSH) gel with a Ca/Si ratio ≤ 0.8. Although there are potential implications for the performance of the spent fuel and cladding due to the presence of hyperalkaline fluids from cement, the principal focus for safety assessment lies with the behaviour of bentonite. There are a number of potential constraints on the interaction of hyperalkaline cement pore fluids with bentonite, including mass balance, thermodynamic issues, mass transport, and kinetics, but none of these is likely to be limiting if conventional OPC cements are employed in repository construction. Nevertheless: Low-pH cements may supply approximately 50 % less hydroxyl ions than conventional OPC for a given volume of cement, but mass balance constraints are complicated by the uncertainty concerning the type of secondary minerals produced during cement-bentonite interaction. The change of aqueous

  19. Low pH Cements

    Energy Technology Data Exchange (ETDEWEB)

    Savage, David; Benbow, Steven [Quintessa Ltd., Henley-on-Thames (United Kingdom)

    2007-05-15

    The development of low-pH cements for use in geological repositories for radioactive waste stems from concerns over the potential for deleterious effects upon the host rock and other EBS materials (notably bentonite) under the hyperalkaline conditions (pH > 12) of cement pore fluids. Low pH cement (also known as low heat cement) was developed by the cement industry for use where large masses of cement (e.g. dams) could cause problems regarding heat generated during curing. In low pH cements, the amount of cement is reduced by substitution of materials such as fly ash, blast furnace slag, silica fume, and/or non-pozzolanic silica flour. SKB and Posiva have ruled out the use of blast furnace slag and fly-ash and are focusing on silica fume as a blending agent. Currently, no preferred composition has been identified by these agencies. SKB and Posiva have defined a pH limit {<=} 11 for cement grout leachates. To attain this pH, blending agents must comprise at least 50 wt % of dry materials. Because low pH cement has little, or no free portlandite, the cement consists predominantly of calcium silicate hydrate (CSH) gel with a Ca/Si ratio {<=} 0.8. Although there are potential implications for the performance of the spent fuel and cladding due to the presence of hyperalkaline fluids from cement, the principal focus for safety assessment lies with the behaviour of bentonite. There are a number of potential constraints on the interaction of hyperalkaline cement pore fluids with bentonite, including mass balance, thermodynamic issues, mass transport, and kinetics, but none of these is likely to be limiting if conventional OPC cements are employed in repository construction. Nevertheless: Low-pH cements may supply approximately 50 % less hydroxyl ions than conventional OPC for a given volume of cement, but mass balance constraints are complicated by the uncertainty concerning the type of secondary minerals produced during cement-bentonite interaction. The change of aqueous

  20. Evaluating high pH for control of dreissenid mussels

    Directory of Open Access Journals (Sweden)

    Dave Evans

    2013-04-01

    Full Text Available Two field experiments were carried out using a custom built flow-through laboratory to test the effect of elevated pH on dreissenid musselsas a potential control method. Both experiments tested the ability of dreissenid pediveligers to settle under conditions of elevated pH and thelong-term survival of adult dreissenids under the same conditions. The two experimental sites had different water quality and differentspecies of dreissenids present. The settlement of quagga mussel pediveligers at the lower Colorado River was inhibited with increasing pH.At the maximum achieved pH of 9.1, there was approximately 90% reduction compared to the maximum settlement observed in the controls.Since the settlement was almost as low in pH 8.9 as at pH 9.1, the inhibition in settlement may have been due to the presence of a precipitateformed under high pH conditions rather than the increase in background pH. No mortality of quagga mussel adults was observed in theexperimental pH levels at the lower Colorado River. At San Justo Reservoir, zebra mussel settlement decreased with increasing pH. Newsettlement was almost entirely absent at the highest pH tested (pH 9.6. The observed mortality of adult zebra mussels was low, but did tendto increase with increasing pH. We also tested the response of adult zebra mussels to short-term exposure to very high pH levels (i.e. pH 10,11, and 12. Adult mussels in poor physical condition experienced 90% mortality after 12 hours at pH 12. For unstressed adult zebra mussels,90% mortality was reached after 120 hours at pH 12. Significant mortalities were also observed both at pH 10 and pH 11. From this study,we conclude that pH elevation could be used both as a preventative treatment to eliminate settlement by dreissenid mussels and as an end ofseason treatment to eliminate adults. The high pH treatment would have to be tailored to the site water quality to prevent formation ofprecipitate during treatment and to minimize corrosive

  1. The γ-aminobutyric acid-producing ability under low pH conditions of lactic acid bacteria isolated from traditional fermented foods of Ishikawa Prefecture, Japan, with a strong ability to produce ACE-inhibitory peptides.

    Science.gov (United States)

    Barla, Florin; Koyanagi, Takashi; Tokuda, Naoko; Matsui, Hiroshi; Katayama, Takane; Kumagai, Hidehiko; Michihata, Toshihide; Sasaki, Tetsuya; Tsuji, Atsushi; Enomoto, Toshiki

    2016-06-01

    Many traditional fermented products are onsumed in Ishikawa Prefecture, Japan, such as kaburazushi , narezushi , konkazuke , and ishiru. Various kinds of lactic acid bacteria (LAB) are associated with their fermentation, however, characterization of LAB has not yet been elucidated in detail. In this study, we evaluated 53 isolates of LAB from various traditional fermented foods by taxonomic classification at the species level by analyzing the 16S ribosomal RNA gene (rDNA) sequences and carbohydrate assimilation abilities. We screened isolates that exhibited high angiotensin-converting enzyme (ACE) inhibitory activities in skim milk or soy protein media and produced high γ-aminobutyric acid (GABA) concentrations in culture supernatants when grown in de Man Rogosa Sharpe broth in the presence of 1% (w/v) glutamic acid. The results revealed that 10 isolates, i.e., Lactobacillus buchneri (2 isolates), Lactobacillus brevis (6 isolates), and Weissella hellenica (2 isolates) had a high GABA-producing ability of >500 mg/100 ml after 72 h of incubation at 35 °C. The ACE inhibitory activity of the whey cultured with milk protein by using L. brevis (3 isolates), L. buchneri (2 isolates), and W. hellenica (2 isolates) was stronger than that of all whey cultured with soy protein media, and these IC 50 were GABA-producing activities at pH 3, suggesting that they could be powerful candidates for use in the fermentation of food materials having low pH.

  2. PhD Dissertations

    OpenAIRE

    Redazione Reti Medievali (a cura di)

    2010-01-01

    Report of PhD Dissertations.Anna Airò La scrittura delle regole. Politica e istituzioni a Taranto nel Quattrocento, Tesi di dottorato di ricerca in Storia medievale, Università degli studi di Firenze, 2005 Pasquale Arfé La Clavis Physicae II (316-529) di Honorius Augustodunensis. Studio ed edizione critica, Tesi di dottorato in Storia della filosofia medievale, Università degli Studi di Napoli "L'Orientale", 2005 Alessandro Azzimonti Scrittura agiografica e strutture di potere nell'Italia c...

  3. Path coefficient analysis of zinc dynamics in varying soil environment

    International Nuclear Information System (INIS)

    Rattan, R.K.; Phung, C.V.; Singhal, S.K.; Deb, D.L.; Singh, A.K.

    1994-01-01

    Influence of soil properties on labile zinc, as measured by diethylene-triamine pentaacetic acid (DTPA) and zinc-65, and self-diffusion coefficients of zinc was assessed on 22 surface soil samples varying widely in their characteristics following linear regression and path coefficient analysis techniques. DTPA extractable zinc could be predicted from organic carbon status and pH of the soil with a highly significant coefficient of determination (R 2 =0.84 ** ). Ninety seven per cent variation in isotopically exchangeable zinc was explained by pH, clay content and cation exchange capacity (CEC) of soil. The self-diffusion coefficients (DaZn and DpZn) and buffer power of zinc exhibited exponential relationship with soil properties, pH being the most dominant one. Soil properties like organic matter, clay content etc. exhibited indirect effects on zinc diffusion rates via pH only. (author). 13 refs., 6 tabs

  4. Esophageal pH monitoring

    Science.gov (United States)

    pH monitoring - esophageal; Esophageal acidity test ... Esophageal pH monitoring is used to check how much stomach acid is entering the esophagus. It also checks how well the acid is cleared downward into the ...

  5. The γ-aminobutyric acid-producing ability under low pH conditions of lactic acid bacteria isolated from traditional fermented foods of Ishikawa Prefecture, Japan, with a strong ability to produce ACE-inhibitory peptides

    Directory of Open Access Journals (Sweden)

    Florin Barla

    2016-06-01

    Full Text Available Many traditional fermented products are onsumed in Ishikawa Prefecture, Japan, such as kaburazushi, narezushi, konkazuke, and ishiru. Various kinds of lactic acid bacteria (LAB are associated with their fermentation, however, characterization of LAB has not yet been elucidated in detail. In this study, we evaluated 53 isolates of LAB from various traditional fermented foods by taxonomic classification at the species level by analyzing the 16S ribosomal RNA gene (rDNA sequences and carbohydrate assimilation abilities. We screened isolates that exhibited high angiotensin-converting enzyme (ACE inhibitory activities in skim milk or soy protein media and produced high γ-aminobutyric acid (GABA concentrations in culture supernatants when grown in de Man Rogosa Sharpe broth in the presence of 1% (w/v glutamic acid. The results revealed that 10 isolates, i.e., Lactobacillus buchneri (2 isolates, Lactobacillus brevis (6 isolates, and Weissella hellenica (2 isolates had a high GABA-producing ability of >500 mg/100 ml after 72 h of incubation at 35 °C. The ACE inhibitory activity of the whey cultured with milk protein by using L. brevis (3 isolates, L. buchneri (2 isolates, and W. hellenica (2 isolates was stronger than that of all whey cultured with soy protein media, and these IC50 were < 1 mg protein/ml. Three of 10 isolates had high GABA-producing activities at pH 3, suggesting that they could be powerful candidates for use in the fermentation of food materials having low pH.

  6. The Effect of pH on Slurry Erosion-Corrosion of Tungsten Carbide Overlays Alloyed with Ru

    Science.gov (United States)

    Nelwalani, Ndivhuwo B.; van der Merwe, Josias W.

    2018-02-01

    The aim of the study was to determine the effect of Ru additions to WC-Fe overlays when exposed to low pH slurry erosion conditions. These overlays were applied through Plasma Transferred Arc, and the original bulk Ru powder concentrations varied from 0.5 to 5 wt.%. A slurry jet impingement erosion-corrosion test rig was used to evaluate wear, and electrochemical measurements were performed to characterize the corrosion properties. The slurry mixtures contained silica sand and synthetic mine water. The pH was varied between 3 and 6.5 for the slurry erosion tests and lowered further for the corrosion characterization. Samples were examined optically and with a scanning electron microscope using energy-dispersive x-ray spectroscopy. X-ray diffraction analysis was used to determine the phases present. For the slurry erosion-corrosion results at the pH of 6.5, addition of Ru did not show a decrease in erosion-corrosion rates. However, when the pH was decreased to 3, by the addition of HCl, Ru improved the resistance. From the electrochemistry, it was also clear that Ru additions improved the corrosion resistance, but more than 1 wt.% Ru was required. At very low pH levels, the presence of Ru was not able to prevent corrosion.

  7. Condition varies with habitat choice in postbreeding forest birds

    Science.gov (United States)

    Scott H. Stoleson

    2013-01-01

    Many birds that are experiencing population declines require extensive tracts of mature forest habitat for breeding. Recent work suggests that at least some may shift their habitat use to early-successional areas after nesting but before migration. I used constant-effort mist netting in regenerating clearcuts (4-8 years postcut) and dense mature-forest understories to...

  8. Spectroscopy on metal-halide lamps under varying gravity conditions

    NARCIS (Netherlands)

    Flikweert, A.J.

    2008-01-01

    Worldwide, 20% of all electricity is used for lighting. For this reason, efficient lamps are economically and ecologically important. High intensity discharge (HID) lamps are efficient lamps. The most common HID lamp these days is the metal-halide (MH) lamp. MH lamps have a good colour rendering

  9. Skin pH, Atopic Dermatitis, and Filaggrin Mutations

    DEFF Research Database (Denmark)

    Bandier, Josefine; Johansen, Jeanne Duus; Petersen, Lars Jelstrup

    2014-01-01

    mutations may influence skin pH. OBJECTIVE: We aimed to determine the epidermal pH in different groups stratified by filaggrin mutations and atopic dermatitis. Further, we investigated the changes in pH according to severity of mutational status among patients with dermatitis, irrespective of skin condition....... METHODS: pH was measured with a multiprobe system pH probe (PH 905), and the study population was composed of 67 individuals, who had all been genotyped for 3 filaggrin mutations (R501X, 2282del4, R2447X). RESULTS: We found no clear pattern in relation to filaggrin mutation carrier status. Individuals...... with wild-type filaggrin displayed both the most acidic and most alkaline values independent of concomitant skin disease; however, no statistical differences between the groups were found. CONCLUSIONS: The lack of significant diversity in skin pH in relation to filaggrin mutation carrier status suggests...

  10. Scales and sources of pH and dissolved oxygen variability in a shallow, upwelling-driven ecosystem

    Science.gov (United States)

    Tanner, C. A.; Martz, T.; Levin, L. A.

    2011-12-01

    semidiurnal pH variability increases 5-fold relative to the magnitude of change during northward alongshore. Applying an empirically-determined alkalinity relationship, we conclude that changes in the carbonate chemistry parameters are largely driven by changes in total carbon. On small spatial scales, cross-shore differences exist in mean oxygen and pH but differences in alongshore mean oxygen and pH at a given depth appears to be negligible. Cross-shore differences can equate to a 0.05 pH unit decrease and 25 μmol kg-1 oxygen decrease over 1 km at a given depth. Strong spatial variability in pH and oxygen conditions exist over vertical gradients in the kelp forest, with mean pH at the surface (7m) being 0.2 pH units greater than at the bottom (17m) and mean oxygen being 104 μmol kg-1 greater. The observed range of pH (7.55-8.22) observed in this shallow environment during the course of a year is greater than open ocean predictions for a global mean pH reduction of 0.2-0.3 units predicted by the year 2100. These results suggest that organisms on exposed upwelling coasts may be adapted to a range of pH conditions and highlight the need for scientists to consider biological response to varying scales of pH change in order to develop more realistic predictions of the impacts of climate change for the coastal zone.

  11. Optoelectronic pH Meter: Further Details

    Science.gov (United States)

    Jeevarajan, Antony S.; Anderson, Mejody M.; Macatangay, Ariel V.

    2009-01-01

    A collection of documents provides further detailed information about an optoelectronic instrument that measures the pH of an aqueous cell-culture medium to within 0.1 unit in the range from 6.5 to 7.5. The instrument at an earlier stage of development was reported in Optoelectronic Instrument Monitors pH in a Culture Medium (MSC-23107), NASA Tech Briefs, Vol. 28, No. 9 (September 2004), page 4a. To recapitulate: The instrument includes a quartz cuvette through which the medium flows as it is circulated through a bioreactor. The medium contains some phenol red, which is an organic pH-indicator dye. The cuvette sits between a light source and a photodetector. [The light source in the earlier version comprised red (625 nm) and green (558 nm) light-emitting diodes (LEDs); the light source in the present version comprises a single green- (560 nm)-or-red (623 nm) LED.] The red and green are repeatedly flashed in alternation. The responses of the photodiode to the green and red are processed electronically to obtain the ratio between the amounts of green and red light transmitted through the medium. The optical absorbance of the phenol red in the green light varies as a known function of pH. Hence, the pH of the medium can be calculated from the aforesaid ratio.

  12. Dynamic patterns and ecological impacts of declining ocean pH in a high-resolution multi-year dataset.

    Science.gov (United States)

    Wootton, J Timothy; Pfister, Catherine A; Forester, James D

    2008-12-02

    Increasing global concentrations of atmospheric CO(2) are predicted to decrease ocean pH, with potentially severe impacts on marine food webs, but empirical data documenting ocean pH over time are limited. In a high-resolution dataset spanning 8 years, pH at a north-temperate coastal site declined with increasing atmospheric CO(2) levels and varied substantially in response to biological processes and physical conditions that fluctuate over multiple time scales. Applying a method to link environmental change to species dynamics via multispecies Markov chain models reveals strong links between in situ benthic species dynamics and variation in ocean pH, with calcareous species generally performing more poorly than noncalcareous species in years with low pH. The models project the long-term consequences of these dynamic changes, which predict substantial shifts in the species dominating the habitat as a consequence of both direct effects of reduced calcification and indirect effects arising from the web of species interactions. Our results indicate that pH decline is proceeding at a more rapid rate than previously predicted in some areas, and that this decline has ecological consequences for near shore benthic ecosystems.

  13. Comparative Studies on the pH Dependence of DOW of Microcystin-RR and -LR Using LC-MS

    Directory of Open Access Journals (Sweden)

    Gaodao Liang

    2011-01-01

    Full Text Available Microcystins (MCs are well known worldwide as hepatotoxins produced by cyanobacteria, but little is known about the physicochemical properties of these compounds. The dependence of the n-octanol/water distribution ratio (DOW of MC-RR and -LR to pH was measured by high-performance liquid chromatography combined with mass spectrometry (LC-MS. There was a remarkable difference in such relationships between MC-RR and -LR. The log DOW of MC-LR decreased from 1.63 at pH 1.0 to -1.26 at pH 6.5, and stabilized between -1.04 and -1.56 at a pH of 6.5~12.0; log DOW of MC-RR varied between -1.24 and -0.67 at a pH of 1.00~4.00, and stabilized between -1.20 and -1.54 at a pH of 4.00~12.00. The difference of hydrophobicity in acidic condition between MC-RR and -LR is important, not only for the analytical method of both toxins, but perhaps also for understanding the difference of toxicity to animals between the two toxins.

  14. Heat-denaturation and aggregation of quinoa (Chenopodium quinoa) globulins as affected by the pH value.

    Science.gov (United States)

    Mäkinen, Outi E; Zannini, Emanuele; Koehler, Peter; Arendt, Elke K

    2016-04-01

    The influence of heating (100 °C; 0-15 min) on the relative molecular mass, protein unfolding and secondary structure of quinoa globulins was studied at pH 6.5 (low solubility), 8.5 and 10.5 (high solubility). The patterns of denaturation and aggregation varied with pH. Heating triggered the disruption of the disulfide bonds connecting the acidic and basic chains of the chenopodin subunits at pH 8.5 and 10.5, but not at pH 6.5. Large aggregates unable to enter a 4% SDS-PAGE gel were formed at pH 6.5 and 8.5, which became soluble under reducing conditions. Heating at pH 10.5 lead to a rapid dissociation of the native chenopodin and to the disruption of the subunits, but no SDS-insoluble aggregates were formed. No major changes in secondary structure occurred during a 15 min heating, but an increase in hydrophobicity indicated unfolding of the tertiary structure in all samples. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. PhD Dissertations

    Directory of Open Access Journals (Sweden)

    Redazione Reti Medievali (a cura di

    2004-06-01

    Full Text Available Report of PhD Dissertations. Francesco Barone Istituzioni, società ed economia a Catania nel tardo medioevo (XIV-XV secolo, Tesi di dottorato in Storia medievale (XVI ciclo, Università degli Studi di Firenze, 2004   Laura Berti Ceroni Il territorio e le strutture di Cesarea e Classe tra tarda antichità e alto medioevo in rapporto con Ravenna, Tesi di dottorato di ricerca in Storia e Informatica, Università degli studi di Bologna, 2002-2003.   Marco Bicchierai Poppi dalla signoria dei conti Guidi al vicariato del Casentino (1360-1480, Tesi di dottorato in Storia medievale (XIV ciclo, Università degli Studi di Firenze, 2004   Emanuela Garimberti Spatiosa ad habitandum loca. Luoghi e identità nella Historia Langobardorum di Paolo Diacono, Tesi di dottorato in Storia medievale (XV ciclo, Università degli Studi di Bologna, 2004   Lorenzo Tanzini Sistemi normativi e pratiche istituzionali a Firenze dalla fine del XIII all’inizio del XV secolo, Tesi di dottorato di ricerca in Storia medievale (XVI ciclo, Università degli Studi di Firenze, 2004   Stefania Tarquini Pellegrinaggio e asseto urbano di Roma, Tesi di dottorato di ricerca in Storia dei centri, delle vie e della cultura dei pellegrinaggi nel Medioevo euro mediterraneo (XV ciclo, Università degli studi di Lecce, 2003

  16. PhD Dissertations

    Directory of Open Access Journals (Sweden)

    Redazione Reti Medievali (a cura di

    2010-06-01

    Full Text Available Report of PhD dissertations. Andrea Brugnoli Una storia locale: l’organizzazione del territorio veronese nel medioevo: trasformazioni della realtà e schemi notarili (IX-metà XII secolo, Tesi di dottorato di ricerca in Scienze Storiche e Antropologiche (XXII ciclo, Università degli Studi di Verona, 2010   Luca Filangieri Famiglie e gruppi dirigenti a Genova (secoli XII-metà XIII, Tesi di dottorato di ricerca in Storia medievale (XXII ciclo, Università degli Studi di Firenze, 2010   Jakub Kujawi ski Wernakularna kolekcja historiograficzna z rękopisu francuskiego nr 688 z Biblioteki Narodowej w Paryżu. Studium źródłoznawcze (La raccolta dei volgarizzamenti delle opere storiografiche nel manoscritto francese 688 della Biblioteca Nazionale di Parigi, Tesi di dottorato, Università “Adam Mickiewicz”, Facoltà di Storia, Pozna, a.a. 2009/2010   Marta Longhi I signori “de Radicata”. Strategie di affermazione familiare e patrimoniale nel Piemonte dei secoli XII-XIV, Tesi di dottorato di ricerca in Istituzioni, Società, Religioni dal Tardo Antico alla fine del Medioevo (XX ciclo, Università di Torino, 2008

  17. PhD Dissertations

    Directory of Open Access Journals (Sweden)

    Redazione Reti Medievali (a cura di

    2003-06-01

    Full Text Available Reporto of PhD Dissertations.   Mario Dalle Carbonare Società, potere e clientele nell’Irlanda altomedievale (secoli V-IX, Tesi di dottorato di ricerca in Storia sociale europea, Università "Ca' Foscari" di Venezia, 2003 Vieri Mazzoni La legislazione antighibellina e la politica oligarchica della Parte Guelfa di Firenze nel secondo Trecento (1347-1378, Tesi di dottorato di ricerca in Storia Medievale (ciclo XII, Università degli Studi di Firenze   Alma Poloni Pisa dalle origini del movimento popolare alla discesa di Ludovico il Bavaro. I gruppi dirigenti cittadini tra continuità e trasformazione, Tesi di dottorato di ricerca in Storia dell'Europa nel medioevo, Università degli studi di Pisa, 2003   Andrea Puglia Potere marchionale, amministrazione del territorio, società locali dalla morte di Ugo di Tuscia a Guelfo VI di Baviera (1001-1160, Tesi di dottorato di ricerca in Storia medievale, Università degli studi di Milano, 2003

  18. H{sub 2x}Mn{sub x}Sn{sub 3-x}S{sub 6}(x=0.11-0.25): a novel reusable sorbent for highly specific Mercury capture under extreme pH conditions

    Energy Technology Data Exchange (ETDEWEB)

    Manos, Manolis J; Kanatzidis, Mercouri G [Department of Chemistry, Northwestern University, Evanston, IL (United States); Petkov, Valeri G [Department of Physics, Central Michigan University, Mt. Pleasant, MI (United States)

    2009-04-09

    The H{sub 2x}Mn{sub x}Sn{sub 3-x}S{sub 6} (x = 0.11-0.25) is a new solid acid with a layered hydrogen metal sulfide (LHMS). It derives from K{sub 2x}Mn{sub x}Sn{sub 3-x}S{sub 6}(x=0.5-0.95) (KMS-1) upon treating it with highly acidic solutions. We demonstrate that LHMS-1 has enormous affinity for the very soft metal ions such as Hg{sup 2+} and Ag{sup +} which occurs via a rapid ion exchange process. The tremendous affinity of LHMS-1 for Hg{sup 2+} is reflected in very high distribution coefficient K{sub d}{sup Hg} values (>10{sup 6} mL g{sup -1}). The large affinity and selectivity of LHMS-1 for Hg{sup 2+} persists in a very wide pH range (from less than zero to nine) and even in the presence of highly concentrated HCl and HNO{sub 3} acids. LHMS-1 is significantly more selective for Hg{sup 2+} and Ag{sup +} than for the less soft cations Pb{sup 2+} and Cd{sup 2+}. The Hg{sup 2+} ions are immobilized in octahedral sites between the sulfide layers of the materials via Hg-S bonds as suggested by pair distribution function (PDF) analysis. LHMS-1 could decrease trace concentrations of Hg{sup 2+} (e.g. <100 ppb) to well below the acceptable limits for the drinking water in less than two min. Hg-laden LHMS-1 shows a remarkable hydrothermal stability and resistance in 6 M HCl solutions. LHMS-1 could be regenerated by treating Hg-loaded samples with 12 M HCl and re-used without loss of its initial exchange capacity. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  19. Variation in pH optima of hydrolytic enzyme activities in tropical rain forest soils.

    Science.gov (United States)

    Turner, Benjamin L

    2010-10-01

    Extracellular enzymes synthesized by soil microbes play a central role in the biogeochemical cycling of nutrients in the environment. The pH optima of eight hydrolytic enzymes involved in the cycles of carbon, nitrogen, phosphorus, and sulfur, were assessed in a series of tropical forest soils of contrasting pH values from the Republic of Panama. Assays were conducted using 4-methylumbelliferone-linked fluorogenic substrates in modified universal buffer. Optimum pH values differed markedly among enzymes and soils. Enzymes were grouped into three classes based on their pH optima: (i) enzymes with acidic pH optima that were consistent among soils (cellobiohydrolase, β-xylanase, and arylsulfatase), (ii) enzymes with acidic pH optima that varied systematically with soil pH, with the most acidic pH optima in the most acidic soils (α-glucosidase, β-glucosidase, and N-acetyl-β-glucosaminidase), and (iii) enzymes with an optimum pH in either the acid range or the alkaline range depending on soil pH (phosphomonoesterase and phosphodiesterase). The optimum pH values of phosphomonoesterase were consistent among soils, being 4 to 5 for acid phosphomonoesterase and 10 to 11 for alkaline phosphomonoesterase. In contrast, the optimum pH for phosphodiesterase activity varied systematically with soil pH, with the most acidic pH optima (3.0) in the most acidic soils and the most alkaline pH optima (pH 10) in near-neutral soils. Arylsulfatase activity had a very acidic optimum pH in all soils (pH ≤3.0) irrespective of soil pH. The differences in pH optima may be linked to the origins of the enzymes and/or the degree of stabilization on solid surfaces. The results have important implications for the interpretation of hydrolytic enzyme assays using fluorogenic substrates.

  20. The influence of pH and media composition on suspension stability of Ag, ZnO, and TiO2 nanoparticles and immobilization of Daphnia magna under guideline testing conditions

    DEFF Research Database (Denmark)

    Cupi, Denisa; Hartmann, Nanna B.; Baun, Anders

    2015-01-01

    In aquatic toxicity testing of engineered nanoparticles (ENPs) the process of agglomeration is very important as it may alter the bioavailability of the ENPs and hence their toxicity. In this study we evaluated test conditions that are more favorable in maintaining a stable and low agglomerate si...

  1. Variation in bacterial ATP concentration during rapid changes in extracellular pH and implications for the activity of attached bacteria.

    Science.gov (United States)

    Albert, Lynal S; Brown, Derick G

    2015-08-01

    In this study we investigated the relationship between a rapid change in extracellular pH and the alteration of bacterial ATP concentration. This relationship is a key component of a hypothesis indicating that bacterial bioenergetics - the creation of ATP from ADP via a proton gradient across the cytoplasmic membrane - can be altered by the physiochemical charge-regulation effect, which results in a pH shift at the bacteria's surface upon adhesion to another surface. The bacterial ATP concentration was measured during a rapid change in extracellular pH from a baseline pH of 7.2 to pH values between 3.5 and 10.5. Experiments were conducted with four neutrophilic bacterial strains, including the Gram-negative Escherichia coli and Pseudomonas putida and the Gram-positive Bacillus subtilis and Staphylococcus epidermidis. A change in bulk pH produced an immediate response in bacterial ATP, demonstrating a direct link between changes in extracellular pH and cellular bioenergetics. In general, the shifts in ATP were similar across the four bacterial strains, with results following an exponential relationship between the extracellular pH and cellular ATP concentration. One exception occurred with S. epidermidis, where there was no variation in cellular ATP at acidic pH values, and this finding is consistent with this species' ability to thrive under acidic conditions. These results provide insight into obtaining a desired bioenergetic response in bacteria through (i) the application of chemical treatments to vary the local pH and (ii) the selection and design of surfaces resulting in local pH modification of attached bacteria via the charge-regulation effect. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. Effect of pH on the structural, optical and morphological properties of Ga-doped ZnO nanoparticles by reflux precipitation method

    Science.gov (United States)

    Ungula, J.; Dejene, B. F.; Swart, H. C.

    2018-04-01

    Gallium-doped zinc oxide nanoparticles (GZO NPs) were synthesized by the reflux precipitation method at 1, 3, 5, 7 and 8 pH conditions of Ga/Zn precursor solution (Ga/Zn sol.). Analysis of X-ray diffraction (XRD) spectra showed that the diffraction peak intensities of GZO NPs increased and the crystallite sizes varied from 11 to 27 nm with an increase in the pH of the Zn/Ga sol. Scanning electron microscopy micrographs showed agglomerated tiny particles that formed on big slabs of nanorods at the lower pH, but fine and enlarged particles on nano-spherical bases formed at the higher pH values. The photoluminescence exciton peak intensities of the GZO NPs and their respective FWHM increased to a maximum at the 5 pH and then reduced slightly as the solution got more basic. The increase of the deep level peak intensities with the increase in the pH followed the XRD diffraction intensity results. It was observed that both the exciton and DLE peaks emission positions shifted to lower wavelengths up to the 5 pH and then red shifted for a further increase in the pH values. The UV-vis analysis also demonstrated that the optical properties of the GZO NPs improved with the increase Ga/Zn sol. pH, as shown by the blue shift of the absorption edge of the reflectance spectra. The band gap energy was tuned from 3.18 to 3.31 eV with the increase in the pH from 1 to 5. An additional increase in the pH yielded no significant change in the optical properties of the GZO NPs.

  3. Coral calcifying fluid pH is modulated by seawater carbonate chemistry not solely seawater pH.

    Science.gov (United States)

    Comeau, S; Tambutté, E; Carpenter, R C; Edmunds, P J; Evensen, N R; Allemand, D; Ferrier-Pagès, C; Tambutté, S; Venn, A A

    2017-01-25

    Reef coral calcification depends on regulation of pH in the internal calcifying fluid (CF) in which the coral skeleton forms. However, little is known about calcifying fluid pH (pH CF ) regulation, despite its importance in determining the response of corals to ocean acidification. Here, we investigate pH CF in the coral Stylophora pistillata in seawater maintained at constant pH with manipulated carbonate chemistry to alter dissolved inorganic carbon (DIC) concentration, and therefore total alkalinity (A T ). We also investigate the intracellular pH of calcifying cells, photosynthesis, respiration and calcification rates under the same conditions. Our results show that despite constant pH in the surrounding seawater, pH CF is sensitive to shifts in carbonate chemistry associated with changes in [DIC] and [A T ], revealing that seawater pH is not the sole driver of pH CF Notably, when we synthesize our results with published data, we identify linear relationships of pH CF with the seawater [DIC]/[H + ] ratio, [A T ]/ [H + ] ratio and [[Formula: see text

  4. Time-varying Crash Risk

    DEFF Research Database (Denmark)

    Christoffersen, Peter; Feunoua, Bruno; Jeon, Yoontae

    We estimate a continuous-time model with stochastic volatility and dynamic crash probability for the S&P 500 index and find that market illiquidity dominates other factors in explaining the stock market crash risk. While the crash probability is time-varying, its dynamic depends only weakly on re...

  5. Eestlased Karlovy Varys / J. R.

    Index Scriptorium Estoniae

    J. R.

    2007-01-01

    Ilmar Raagi mängufilm "Klass" osaleb 42. Karlovy Vary rahvusvahelise filmifestivali võistlusprogrammis "East of the West" ja Asko Kase lühimängufilm "Zen läbi prügi" on valitud festivali kõrvalprogrammi "Forum of Independents"

  6. Esmaklassiline Karlovy Vary / Jaanus Noormets

    Index Scriptorium Estoniae

    Noormets, Jaanus

    2007-01-01

    Ilmar Raagi mängufilm "Klass" võitis 42. Karlovy Vary rahvusvahelise filmifestivalil kaks auhinda - ametliku kõrvalvõistlusprogrammi "East of the West" eripreemia "Special mention" ja Euroopa väärtfilmikinode keti Europa Cinemas preemia. Ka Asko Kase lühifilmi "Zen läbi prügi linastumisest ning teistest auhinnasaajatest ning osalejatest

  7. Optimistlik Karlovy Vary / Jaan Ruus

    Index Scriptorium Estoniae

    Ruus, Jaan, 1938-2017

    2007-01-01

    42. Karlovy Vary rahvusvahelise filmifestivali auhinnatud filmidest (žürii esimees Peter Bart). Kristallgloobuse sai Islandi-Saksamaa "Katseklaasilinn" (režii Baltasar Kormakur), parimaks režissööriks tunnistati norralane Bard Breien ("Negatiivse mõtlemise kunst"). Austraallase Michael James Rowlandi "Hea õnne teekond" sai žürii eripreemia

  8. Effect of pH and phosphate on calcium carbonate polymorphs precipitated at near-freezing temperature

    NARCIS (Netherlands)

    Hu, Yu-Bin; Wolthers, Mariëtte; Wolf-Gladrow, Dieter A.; Nehrke, Gernot

    2015-01-01

    The effects of pH and phosphate on the precipitation of calcium carbonate polymorphs from aqueous solution were investigated. Experiments were carried out at near-freezing temperature and two different pH conditions (pH 13.4 and 9.0). At each pH condition, solutions having different concentrations

  9. Genetic polymorphisms in varied environments.

    Science.gov (United States)

    Powell, J R

    1971-12-03

    Thirteen experimenital populationis of Drosophila willistoni were maintained in cages, in some of which the environments were relatively constant and in others varied. After 45 weeks, the populations were assayed by gel electrophoresis for polymorphisms at 22 protein loci. The average heterozygosity per individual and the average unmber of alleles per locus were higher in populations maintained in heterogeneous environments than in populations in more constant enviroments.

  10. A PhD is a PhD is a PhD

    OpenAIRE

    Ostrow, Deborah Anne

    2017-01-01

    A PhD is a PhD is a PhD is a practice-based project that interrogates the process of an artist undertaking PhD research under established criteria. It consists of an exegesis, an original screenplay, and a digital film made for online viewing, with images drawn from a range of documentaries and films found on YouTube. They have been dissected, re-assembled and then re-embedded to YouTube. The source material covers topics such as medicalization of madness, the conspicuous appropriation of uni...

  11. THE EFFECTS OF TEMPERATURE AND pH ON BACTERIAL ...

    African Journals Online (AJOL)

    PROF EKWUEME

    The effect of temperature and pH on bacterial degradation of latex paint under humid condition by .... blade and plastic bags as described by Okpokwasili and. Ituen(1996) and .... provided different ecological niche for bacteria at favourable ...

  12. The Thermal Collector With Varied Glass Covers

    International Nuclear Information System (INIS)

    Luminosu, I.; Pop, N.

    2010-01-01

    The thermal collector with varied glass covers represents an innovation realized in order to build a collector able to reach the desired temperature by collecting the solar radiation from the smallest surface, with the highest efficiency. In the case of the thermal collector with variable cover glasses, the number of the glass plates covering the absorber increases together with the length of the circulation pipe for the working fluid. The thermal collector with varied glass covers compared to the conventional collector better meet user requirements because: for the same temperature increase, has the collecting area smaller; for the same collection area, realizes the highest temperature increase and has the highest efficiency. This works is addressed to researchers in the solar energy and to engineers responsible with air-conditioning systems design or industrial and agricultural products drying.

  13. The pH Game.

    Science.gov (United States)

    Chemecology, 1996

    1996-01-01

    Describes a game that can be used to teach students about the acidity of liquids and substances around their school and enable them to understand what pH levels tell us about the environment. Students collect samples and measure the pH of water, soil, plants, and other natural material. (DDR)

  14. Kinetic Rate Law Parameter Measurements on a Borosilicate Waste Glass: Effect of Temperature, pH, and Solution Composition on Alkali Ion Exchange

    International Nuclear Information System (INIS)

    Pierce, Eric M.; McGrail, B PETER.; Icenhower, J P.; Rodriguez, Elsa A.; Steele, Jackie L.; Baum, Steven R.

    2004-01-01

    The reaction kinetics of glass is controlled by matrix dissolution and ion exchange (IEX). Dissolution of an alkali-rich simulated borosilicate waste glass was investigated using single-pass flow-through (SPFT) experiments. Experiments were conducted as a function of temperature, pH, and solution composition by varying the SiO 2 (aq) activity in the influent solution. Results showed that under dilute conditions matrix dissolution increased with increasing pH and temperature, and decreased with increasing SiO 2 (aq) activity. IEX rates decreased with increasing pH and temperature, and increased with increasing SiO 2 (aq) activity. Over the solution composition range interrogated in this study the dominant dissolution mechanism changed from matrix dissolution to IEX. These results suggest that ''secondary'' reactions may become dominant under certain environmental conditions and emphasize the need to incorporate these reactions into dissolution rate models

  15. Evaluating high pH for control of dreissenid mussels

    OpenAIRE

    Dave Evans; Sergey E. Mastitsky; Katherine L. Prescott; Thomas H. Prescott; Renata Claudi; Anna Carolina Taraborelli

    2013-01-01

    Two field experiments were carried out using a custom built flow-through laboratory to test the effect of elevated pH on dreissenid musselsas a potential control method. Both experiments tested the ability of dreissenid pediveligers to settle under conditions of elevated pH and thelong-term survival of adult dreissenids under the same conditions. The two experimental sites had different water quality and differentspecies of dreissenids present. The settlement of quagga mussel pediveligers at ...

  16. Growth of aspergillus terreus and the production of itaconic acid in batch and continuous cultures. The influence of pH

    Energy Technology Data Exchange (ETDEWEB)

    Rychtera, M.; Wase, J.D.A.

    1981-01-01

    Aspergillus terreus (NRRL 1960) was cultivated in batch and in continuous single-stage culture. The influence of pH on the growth of the organism, on the formation of itaconic acid and on the kinetics of fermentation was studied under phosphate limitation, both at controlled ph values and also when the pH was allowed to decrease in a natural way. In the pH range 1.7-3.5, the ratio of undissociated:half-dissociated acid varied from 190:1 to 1.5:1. The amount of completely dissociated acid may be regarded as negligible. In batch systems operated without pH control, an initial pH of 3.1 proved to be the most effective. Product formation under such conditions started at a point where the exponential growth phase commenced and was described by a zero-order equation. The maximum itaconic acid production rate was shifted behind maximum growth rate. The continuous single-stage system was first order with respect to product formation. At pH greater than 3.1, a number of aberrant and pellet forms of the mould occurred, resulting in decreased acid production. (Refs. 41).

  17. Varying Constants, Gravitation and Cosmology

    Directory of Open Access Journals (Sweden)

    Jean-Philippe Uzan

    2011-03-01

    Full Text Available Fundamental constants are a cornerstone of our physical laws. Any constant varying in space and/or time would reflect the existence of an almost massless field that couples to matter. This will induce a violation of the universality of free fall. Thus, it is of utmost importance for our understanding of gravity and of the domain of validity of general relativity to test for their constancy. We detail the relations between the constants, the tests of the local position invariance and of the universality of free fall. We then review the main experimental and observational constraints that have been obtained from atomic clocks, the Oklo phenomenon, solar system observations, meteorite dating, quasar absorption spectra, stellar physics, pulsar timing, the cosmic microwave background and big bang nucleosynthesis. At each step we describe the basics of each system, its dependence with respect to the constants, the known systematic effects and the most recent constraints that have been obtained. We then describe the main theoretical frameworks in which the low-energy constants may actually be varying and we focus on the unification mechanisms and the relations between the variation of different constants. To finish, we discuss the more speculative possibility of understanding their numerical values and the apparent fine-tuning that they confront us with.

  18. RIFIFI: Analytical calculation method of the critical condition and flux in a varied regions reactor by two-group theory and one dimension developed for the Mercury-Ferranti computer; Rififi: methode de calcul analytique de la condition critique et des flux d'une pile a regions variees en theorie a deux groupes et a une dimension programmee pour le calculateur electronique Mercury (Ferranti)

    Energy Technology Data Exchange (ETDEWEB)

    Amouyal, A; Bacher, P; Lago, B; Mengin, F L; Parker, E [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1960-07-01

    The calculation method presented in this report has been developed for the Mercury-Ferranti computer of the C.E.N.S. This calculation method allows to resolve the diffusion equations and continuity equations of flux and flow with two groups of neutrons and one dimension in spherical, cylindrical and linear geometry. In the cylindrical and linear configurations, we can take the height and extrapolated radius into account. The critical condition can be realised by varying linearly one or more parameters: k{sub {infinity}}, medium frontier, height or extrapolated radius. The calculation method enables also to calculate the flux, adjoint flux and various integrals. In the first part, it explains what is needed to know before using the method: data presentation, method possibilities, results presentation with some information about restrictions, accuracy and calculation time. The complete formulation of the calculation method is given in the second part. (M.P.)

  19. Changes in microbial communities associated with the sea anemone Anemonia viridis in a natural pH gradient.

    Science.gov (United States)

    Meron, Dalit; Buia, Maria-Cristina; Fine, Maoz; Banin, Ehud

    2013-02-01

    Ocean acidification, resulting from rising atmospheric carbon dioxide concentrations, is a pervasive stressor that can affect many marine organisms and their symbionts. Studies which examine the host physiology and microbial communities have shown a variety of responses to the ocean acidification process. Recently, several studies were conducted based on field experiments, which take place in natural CO(2) vents, exposing the host to natural environmental conditions of varying pH. This study examines the sea anemone Anemonia viridis which is found naturally along the pH gradient in Ischia, Italy, with an aim to characterize whether exposure to pH impacts the holobiont. The physiological parameters of A. viridis (Symbiodinium density, protein, and chlorophyll a+c concentration) and its microbial community were monitored. Although reduction in pH was seen to have had an impact on composition and diversity of associated microbial communities, no significant changes were observed in A. viridis physiology, and no microbial stress indicators (i.e., pathogens, antibacterial activity, etc.) were detected. In light of these results, it appears that elevated CO(2) does not have a negative influence on A. viridis that live naturally in the site. This suggests that natural long-term exposure and dynamic diverse microbial communities may contribute to the acclimation process of the host in a changing pH environment.

  20. Aerobic decolourization of two reactive azo dyes under varying ...

    African Journals Online (AJOL)

    Bacillus cereus isolated from dye industrial waste, that is, effluent and soil samples was screened for its ability to decolourize two reactive azo dye – cibacron black PSG and cibacron red P4B under aerobic conditions at pH 7 and incubated at 35°C over a five day period. Different carbon and nitrogen sources were used for ...

  1. Extracellular pH modulates GABAergic neurotransmission in rat hypothalamus.

    Science.gov (United States)

    Chen, Z L; Huang, R Q

    2014-06-20

    Changes in extracellular pH have a modulatory effect on GABAA receptor function. It has been reported that pH sensitivity of the GABA receptor is dependent on subunit composition and GABA concentration. Most of previous investigations focused on GABA-evoked currents, which only reflect the postsynaptic receptors. The physiological relevance of pH modulation of GABAergic neurotransmission is not fully elucidated. In the present studies, we examined the influence of extracellular pH on the GABAA receptor-mediated inhibitory neurotransmission in rat hypothalamic neurons. The inhibitory postsynaptic currents (IPSCs), tonic currents, and the GABA-evoked currents were recorded with whole-cell patch techniques on the hypothalamic slices from Sprague-Dawley rats at 15-26 postnatal days. The amplitude and frequency of spontaneous GABA IPSCs were significantly increased while the external pH was changed from 7.3 to 8.4. In the acidic pH (6.4), the spontaneous GABA IPSCs were reduced in amplitude and frequency. The pH induced changes in miniature GABA IPSCs (mIPSCs) similar to that in spontaneous IPSCs. The pH effect on the postsynaptic GABA receptors was assessed with exogenously applied varying concentrations of GABA. The tonic currents and the currents evoked by sub-saturating concentration of GABA ([GABA]) (10 μM) were inhibited by acidic pH and potentiated by alkaline pH. In contrast, the currents evoked by saturating [GABA] (1mM) were not affected by pH changes. We also investigated the influence of pH buffers and buffering capacity on pH sensitivity of GABAA receptors on human recombinant α1β2γ2 GABAA receptors stably expressed in HEK 293 cells. The pH influence on GABAA receptors was similar in HEPES- and MES-buffered media, and not dependent on protonated buffers, suggesting that the observed pH effect on GABA response is a specific consequence of changes in extracellular protons. Our data suggest that the hydrogen ions suppress the GABAergic neurotransmission

  2. Weighted approximation with varying weight

    CERN Document Server

    Totik, Vilmos

    1994-01-01

    A new construction is given for approximating a logarithmic potential by a discrete one. This yields a new approach to approximation with weighted polynomials of the form w"n"(" "= uppercase)P"n"(" "= uppercase). The new technique settles several open problems, and it leads to a simple proof for the strong asymptotics on some L p(uppercase) extremal problems on the real line with exponential weights, which, for the case p=2, are equivalent to power- type asymptotics for the leading coefficients of the corresponding orthogonal polynomials. The method is also modified toyield (in a sense) uniformly good approximation on the whole support. This allows one to deduce strong asymptotics in some L p(uppercase) extremal problems with varying weights. Applications are given, relating to fast decreasing polynomials, asymptotic behavior of orthogonal polynomials and multipoint Pade approximation. The approach is potential-theoretic, but the text is self-contained.

  3. Estrelas variáveis

    OpenAIRE

    Viana, Sérgio Manuel de Oliveira

    2001-01-01

    A observação do céu nocturno é uma prática que vem da Antiguidade. Desde então e durante muito tempo pensou-se que as estrelas mantinham o brilho constante. Assim foi até ao século XVI, quando David Fabricius observou uma estrela cujo brilho variava periodicamente. Dois séculos mais tarde, Jonh Goodricke descobriu uma segunda estrela e com o desenvolvimento de instrumentos de observação este conjunto foi muito alargado e hoje inclui o Sol.A variação do brilho das estrelas variáveis permite d...

  4. Pemodelan Markov Switching Dengan Time-varying Transition Probability

    OpenAIRE

    Savitri, Anggita Puri; Warsito, Budi; Rahmawati, Rita

    2016-01-01

    Exchange rate or currency is an economic variable which reflects country's state of economy. It fluctuates over time because of its ability to switch the condition or regime caused by economic and political factors. The changes in the exchange rate are depreciation and appreciation. Therefore, it could be modeled using Markov Switching with Time-Varying Transition Probability which observe the conditional changes and use information variable. From this model, time-varying transition probabili...

  5. Urine pH test

    Science.gov (United States)

    ... urine test Male urinary tract References Bose A, Monk RD, Bushinsky DA. Kidney stones. In: Melmed S, Polonsky ... and its influence on urine pH. J Am Diet Assoc . 1995;95(7):791-797. PMID: 7797810 ...

  6. Exercise and Pulmonary Hypertension (PH)

    Science.gov (United States)

    ... Situations Find a Doctor PH Care Centers PHA Classroom PHA Registry Insurance Guide Specialty Pharmacy Other Resources ... no published data in the medical literature regarding routine exercise in patients with PAH. However, there are ...

  7. Influence of pH on pesticide sorption by soil containing wheat residue-derived char

    International Nuclear Information System (INIS)

    Sheng Guangyao; Yang Yaning; Huang Minsheng; Yang Kai

    2005-01-01

    Field burning of crop residues incorporates resulting chars into soil and may thus influence the environmental fate of pesticides in the soil. This study evaluated the influence of pH on the sorption of diuron, bromoxynil, and ametryne by a soil in the presence and absence of a wheat residue-derived char. The sorption was measured at pHs ∼3.0 and ∼7.0. Wheat char was found to be a highly effective sorbent for the pesticides, and its presence (1% by weight) in soil contributed >70% to the pesticide sorption (with one exception). The sorption of diuron was not influenced by pH, due to its electroneutrality. Bromoxynil becomes dissociated at high pHs to form anionic species. Its sorption by soil and wheat char was lower at pH ∼7.0 than at pH ∼3.0, probably due to reduced partition of the anionic species of bromoxynil into soil organic matter and its weak interaction with the carbon surface of the char. Ametryne in its molecular form at pH ∼7.0 was sorbed by char-amended soil via partitioning into soil organic matter and interaction with the carbon surface of the char. Protonated ametryne at pH ∼3.0 was substantially sorbed by soil primarily via electrostatic forces. Sorption of protonated ametryne by wheat char was also significant, likely due not only to the interaction with the carbon surface but also to interactions with hydrated silica and surface functional groups of the char. Sorption of ametryne by char-amended soil at pH ∼3.0 was thus influenced by both the soil and the char. Environmental conditions may thus significantly influence the sorption and behavior of pesticides in agricultural soils containing crop residue-derived chars. - Wheat char was effective for adsorption of pesticides in soil, with efficacy varying with pH and particular pesticides

  8. Influence of pH on pesticide sorption by soil containing wheat residue-derived char

    Energy Technology Data Exchange (ETDEWEB)

    Sheng Guangyao [Department of Crop, Soil, and Environmental Sciences, University of Arkansas, Fayetteville, AR 72701 (United States)]. E-mail: gsheng@uark.edu; Yang Yaning [Department of Crop, Soil, and Environmental Sciences, University of Arkansas, Fayetteville, AR 72701 (United States); Huang Minsheng [Department of Environmental Science and Technology, East China Normal University, Shanghai 200062 (China); Yang Kai [Department of Environmental Science and Technology, East China Normal University, Shanghai 200062 (China)

    2005-04-01

    Field burning of crop residues incorporates resulting chars into soil and may thus influence the environmental fate of pesticides in the soil. This study evaluated the influence of pH on the sorption of diuron, bromoxynil, and ametryne by a soil in the presence and absence of a wheat residue-derived char. The sorption was measured at pHs {approx}3.0 and {approx}7.0. Wheat char was found to be a highly effective sorbent for the pesticides, and its presence (1% by weight) in soil contributed >70% to the pesticide sorption (with one exception). The sorption of diuron was not influenced by pH, due to its electroneutrality. Bromoxynil becomes dissociated at high pHs to form anionic species. Its sorption by soil and wheat char was lower at pH {approx}7.0 than at pH {approx}3.0, probably due to reduced partition of the anionic species of bromoxynil into soil organic matter and its weak interaction with the carbon surface of the char. Ametryne in its molecular form at pH {approx}7.0 was sorbed by char-amended soil via partitioning into soil organic matter and interaction with the carbon surface of the char. Protonated ametryne at pH {approx}3.0 was substantially sorbed by soil primarily via electrostatic forces. Sorption of protonated ametryne by wheat char was also significant, likely due not only to the interaction with the carbon surface but also to interactions with hydrated silica and surface functional groups of the char. Sorption of ametryne by char-amended soil at pH {approx}3.0 was thus influenced by both the soil and the char. Environmental conditions may thus significantly influence the sorption and behavior of pesticides in agricultural soils containing crop residue-derived chars. - Wheat char was effective for adsorption of pesticides in soil, with efficacy varying with pH and particular pesticides.

  9. PhEDEx Data Service

    International Nuclear Information System (INIS)

    Egeland, Ricky; Wildish, Tony; Huang, Chih-Hao

    2010-01-01

    The PhEDEx Data Service provides access to information from the central PhEDEx database, as well as certificate-authenticated managerial operations such as requesting the transfer or deletion of data. The Data Service is integrated with the 'SiteDB' service for fine-grained access control, providing a safe and secure environment for operations. A plug-in architecture allows server-side modules to be developed rapidly and easily by anyone familiar with the schema, and can automatically return the data in a variety of formats for use by different client technologies. Using HTTP access via the Data Service instead of direct database connections makes it possible to build monitoring web-pages with complex drill-down operations, suitable for debugging or presentation from many aspects. This will form the basis of the new PhEDEx website in the near future, as well as providing access to PhEDEx information and certificate-authenticated services for other CMS dataflow and workflow management tools such as CRAB, WMCore, DBS and the dashboard. A PhEDEx command-line client tool provides one-stop access to all the functions of the PhEDEx Data Service interactively, for use in simple scripts that do not access the service directly. The client tool provides certificate-authenticated access to managerial functions, so all the functions of the PhEDEx Data Service are available to it. The tool can be expanded by plug-ins which can combine or extend the client-side manipulation of data from the Data Service, providing a powerful environment for manipulating data within PhEDEx.

  10. Programmable pH buffers

    Science.gov (United States)

    Gough, Dara Van; Huber, Dale L.; Bunker, Bruce C.; Roberts, Mark E.

    2017-01-24

    A programmable pH buffer comprises a copolymer that changes pK.sub.a at a lower critical solution temperature (LCST) in water. The copolymer comprises a thermally programmable polymer that undergoes a hydrophobic-to-hydrophilic phase change at the LCST and an electrolytic polymer that exhibits acid-base properties that are responsive to the phase change. The programmable pH buffer can be used to sequester CO.sub.2 into water.

  11. Diurnal variation in ruminal pH on the digestibility of highly digestible perennial ryegrass during continuous culture fermentation.

    Science.gov (United States)

    Wales, W J; Kolver, E S; Thorne, P L; Egan, A R

    2004-06-01

    Dairy cows grazing high-digestibility pastures exhibit pronounced diurnal variation in ruminal pH, with pH being below values considered optimal for digestion. Using a dual-flow continuous culture system, the hypothesis that minimizing diurnal variation in pH would improve digestion of pasture when pH was low, but not at a higher pH, was tested. Four treatments were imposed, with pH either allowed to exhibit normal diurnal variation around an average pH of 6.1 or 5.6, or maintained at constant pH. Digesta samples were collected during the last 3 d of each of four, 9-d experimental periods. A constant pH at 5.6 compared with a constant pH of 6.1 reduced the digestibility of organic matter (OM), neutral detergent (NDF), and acid detergent fiber (ADF) by 7, 14, and 21%, respectively. When pH was allowed to vary (averaging 5.6), digestion of OM, NDF, and ADF were reduced by 15,30, and 36%, respectively, compared with pH varying at 6.1. There was little difference in digestion parameters when pH was either constant or varied with an average pH of 6.1. However, when average pH was 5.6, maintaining a constant pH significantly increased digestion of OM, NDF, and ADF by 5, 25, and 24% compared with a pH that exhibited normal diurnal variation. These in vitro results show that gains in digestibility and potential milk production can be made by minimizing diurnal variation in ruminal pH, but only when ruminal pH is low (5.6). However, larger gains in productivity can be achieved by increasing average daily ruminal pH from 5.6 to 6.1.

  12. Quantification of pH gradients and implications in insulator-based dielectrophoresis of biomolecules.

    Science.gov (United States)

    Gencoglu, Aytug; Camacho-Alanis, Fernanda; Nguyen, Vi Thanh; Nakano, Asuka; Ros, Alexandra; Minerick, Adrienne R

    2011-09-01

    Direct current (DC) insulator-based dielectrophoretic (iDEP) microdevices have the potential to replace traditional alternating current dielectrophoretic devices for many cellular and biomolecular separation applications. The use of large DC fields suggest that electrode reactions and ion transport mechanisms can become important and impact ion distributions in the nanoliters of fluid in iDEP microchannels. This work tracked natural pH gradient formation in a 100 μm wide, 1 cm-long microchannel under applicable iDEP protein manipulation conditions. Using fluorescence microscopy with the pH-sensitive dye FITC Isomer I and the pH-insensitive dye TRITC as a reference, pH was observed to drop drastically in the microchannels within 1 min in a 3000 V/cm electric field; pH drops were observed in the range of 6-10 min within a 100 V/cm electric field and varied based on the buffer conductivity. To address concerns of dye transport impacting intensity data, electrokinetic mobilities of FITC were carefully examined and found to be (i) toward the anode and (ii) 1 to 2 orders of magnitude smaller than H⁺ transport which is responsible for pH drops from the anode toward the cathode. COMSOL simulations of ion transport showed qualitative agreement with experimental results. The results indicate that pH changes are severe enough and rapid enough to influence the net charge of a protein or cause aggregation during iDEP experiments. The results also elucidate reasonable time periods over which the phosphate buffering capacity can counter increases in H⁺ and OH⁻ for unperturbed iDEP manipulations. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Modulation of Connexin-36 Gap Junction Channels by Intracellular pH and Magnesium Ions.

    Science.gov (United States)

    Rimkute, Lina; Kraujalis, Tadas; Snipas, Mindaugas; Palacios-Prado, Nicolas; Jotautis, Vaidas; Skeberdis, Vytenis A; Bukauskas, Feliksas F

    2018-01-01

    Connexin-36 (Cx36) protein forms gap junction (GJ) channels in pancreatic beta cells and is also the main Cx isoform forming electrical synapses in the adult mammalian brain. Cx36 GJs can be regulated by intracellular pH (pH i ) and cytosolic magnesium ion concentration ([Mg 2+ ] i ), which can vary significantly under various physiological and pathological conditions. However, the combined effect and relationship of these two factors over Cx36-dependent coupling have not been previously studied in detail. Our experimental results in HeLa cells expressing Cx36 show that changes in both pH i and [Mg 2+ ] i affect junctional conductance (g j ) in an interdependent manner; in other words, intracellular acidification cause increase or decay in g j depending on whether [Mg 2+ ] i is high or low, respectively, and intracellular alkalization cause reduction in g j independently of [Mg 2+ ] i . Our experimental and modelling data support the hypothesis that Cx36 GJ channels contain two separate gating mechanisms, and both are differentially sensitive to changes in pH i and [Mg 2+ ] i . Using recombinant Cx36 we found that two glutamate residues in the N-terminus could be partly responsible for the observed interrelated effect of pH i and [Mg 2+ ] i . Mutation of glutamate at position 8 attenuated the stimulatory effect of intracellular acidification at high [Mg 2+ ] i , while mutation at position 12 and double mutation at both positions reversed stimulatory effect to inhibition. Moreover, Cx36 * E8Q lost the initial increase of g j at low [Mg 2+ ] i and double mutation lost the sensitivity to high [Mg 2+ ] i . These results suggest that E8 and E12 are involved in regulation of Cx36 GJ channels by Mg 2+ and H + ions.

  14. Helicobacter pylori colonization critically depends on postprandial gastric conditions

    Science.gov (United States)

    Bücker, Roland; Azevedo-Vethacke, Marina; Groll, Claudia; Garten, Désirée; Josenhans, Christine; Suerbaum, Sebastian; Schreiber, Sören

    2012-01-01

    The risk of Helicobacter pylori infection is highest in childhood, but the colonization process of the stomach mucosa is poorly understood. We used anesthetized Mongolian gerbils to study the initial stages of H. pylori colonization. Prandial and postprandial gastric conditions characteristic of humans of different ages were simulated. The fraction of bacteria that reached the deep mucus layer varied strongly with the modelled postprandial conditions. Colonization success was weak with fast gastric reacidification typical of adults. The efficiency of deep mucus entry was also low with a slow pH decrease as seen in pH profiles simulating the situation in babies. Initial colonization was most efficient under conditions simulating the postprandial reacidification and pepsin activation profiles in young children. In conclusion, initial H. pylori colonization depends on age-related gastric physiology, providing evidence from an in vivo infection model that suggests an explanation why the bacterium is predominantly acquired in early childhood. PMID:23251780

  15. Decolorisation of Congo Red by Aeromonas hydrophila Under Microaerophilic Conditions

    International Nuclear Information System (INIS)

    El Gizawy, S.; Refae, R.A.; Abd El Kareem, H.; Gomaa, O.M.; Hamed, H.

    2009-01-01

    Among 22 local bacterial isolates, Aeromonas hydrophila isolated from Bolti fish showed a remarkable ability to decolorize congo red under microaerophilic conditions (98.8% in 48 hrs) without prior adaptation. The bacterium had the ability to grow and decolorized high concentrations of congo red which varied from 50 to 1000 mg/l , the decolorisation was irrelevant to bacterial growth. The strain was capable of decolorizing congo red under a wide range of temperatures (20-40 degree C), ph (3-8), NaCl (0-200 mg/l) and also had the ability to decolorized mono, di and poly azo dyes. This bacterium is notable in its ability to decolorized the diazo congo red under extreme conditions of temperature, ph, salinity and high dye concentrations which makes it suitable for decolorisation under extreme industrial conditions

  16. Critical assessment of the pH of children's soap

    Directory of Open Access Journals (Sweden)

    Bruna Rafaela Mendes

    2016-06-01

    Full Text Available Abstract Objective: To evaluate the pH value of children's antibacterial soaps and syndets used in children's baths and verify whether there is information regarding pH on the product label. Methods: Quantitative, cross-sectional, analytical observational study that included ninety soap samples, both in bar and liquid presentations, as follows: 67 children's soap (group 1, 17 antibacterial soaps (group 2, and 6 syndets (group 3. Each sample had its pH measured after 1% dilution. In addition to descriptive statistics, the Pearson-Yates chi-squared test and Student's t-tests were applied, considering the minimal significance level of 5%. The Wilcoxon-Mann-Whitney test, Fisher's exact test, and the Kruskal-Wallis test were used for inferential statistics. Results: The pH levels varied considerably between liquid and bar presentations, with lower levels (4.4-7.9 found for the liquids (p < 0.05. Syndets showed pH levels close to the ideal (slightly acid and the antibacterial soaps showed the highest pH levels (up to 11.34 (p < 0.05. Only two of the soaps included in the study had information about their pH levels on the product packaging. Conclusions: Knowledge of the pH of children's soap by doctors and users is important, considering the great pH variability found in this study. Moreover, liquid soaps, and especially syndets, are the most recommended for the sensitive skin of neonates and infants, in order to guarantee skin barrier efficacy.

  17. Critical assessment of the pH of children's soap.

    Science.gov (United States)

    Mendes, Bruna Rafaela; Shimabukuro, Danielle Midori; Uber, Marjorie; Abagge, Kerstin Taniguchi

    2016-01-01

    To evaluate the pH value of children's antibacterial soaps and syndets used in children's baths and verify whether there is information regarding pH on the product label. Quantitative, cross-sectional, analytical observational study that included ninety soap samples, both in bar and liquid presentations, as follows: 67 children's soap (group 1), 17 antibacterial soaps (group 2), and 6 syndets (group 3). Each sample had its pH measured after 1% dilution. In addition to descriptive statistics, the Pearson-Yates chi-squared test and Student's t-tests were applied, considering the minimal significance level of 5%. The Wilcoxon-Mann-Whitney test, Fisher's exact test, and the Kruskal-Wallis test were used for inferential statistics. The pH levels varied considerably between liquid and bar presentations, with lower levels (4.4-7.9) found for the liquids (p<0.05). Syndets showed pH levels close to the ideal (slightly acid) and the antibacterial soaps showed the highest pH levels (up to 11.34) (p<0.05). Only two of the soaps included in the study had information about their pH levels on the product packaging. Knowledge of the pH of children's soap by doctors and users is important, considering the great pH variability found in this study. Moreover, liquid soaps, and especially syndets, are the most recommended for the sensitive skin of neonates and infants, in order to guarantee skin barrier efficacy. Copyright © 2016 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda. All rights reserved.

  18. Effect of pH on sludge composting

    International Nuclear Information System (INIS)

    Hashimoto, Shoji; Watanabe, Hiromasa; Nishimura, Koichi; Kawakami, Waichiro

    1984-01-01

    The effect of pH on composting of irradiated sewage sludge was discussed. Inorganic materials, such as activated alumina, Kanuma-soil, and Akadama-soil, were used as bulking agents. Na 2 CO 3 was used as a pH adjuster. The fermentations were done isothermally at the optimum temperature, 50 0 C. The rate of CO 2 evolution increased initially with time, and then, decreased. The peak value of CO 2 evolution and the time to attain the peak varied by the addition of Na 2 CO 3 . When Kanuma-soil was used as the bulking agent, for example, the peak value became larger as the amount of Na 2 CO 3 was increased to 1.0 % and became smaller over this value. From pH measurements, it was found that the optimum pH for fermentation was ranged from 6 to 8 when activated alumina was used. When other bulking agents were used, the maximum value of CO 2 evolution rate was obtained at pH 7 to 8.5. The peak value and the peak time also varied by the addition of NH 3 in the aeration gas. (author)

  19. Biological degradation of EDTA in pulping effluents at higher pH - a laboratory study

    Energy Technology Data Exchange (ETDEWEB)

    Ek, M; Remberger, M; Allard, A S

    1999-01-01

    The biological degradation of EDTA at different pH, sludge load and sludge age has been investigated in laboratory experiments. The experiments showed that relatively fast degradation of EDTA in the form found in this waste water (from production of TMP) took place at least at pH around 8.5 with moderate COD load and high sludge age. In continuous reactors the degradation of EDTA in a pulp and paper waste water was 2-3 mg EDTA/g SS*day at both pH 7 and 8,5, and at sludge ages from 5 to 21 days. The degradation was dependent on sludge load, and no degradation was seen above 1 g COD/g SS*day. In kinetic experiments with half strength waste water the same degradation rate (1,5-2 mg EDTA/g SS*day) was found at pH 7 and at pH 8,5 with sludge of low age (9 and 5 days SRT). Much faster degradation was found at pH 8,5 with sludge of high age (21 days in the continuous experiment). The mean degradation rate was over 10 mg EDTA/g SS*day from 20 to 5 mg EDTA/l. v{sub max} was determined to be 35 mg EDTA/g SS*day and K{sub M} to 31 mg EDTA/l. COD removal was at least as good at pH 8,5 as at pH 7. Sludge properties were best at pH 8,5 and long sludge retention time (giving low sludge load). Both sludge volume index and residual suspended solids after sedimentation were lower than under normal conditions at pH 7. The direct cost for caustic lime would be about 15 SEK per ton of TMP, with a water like the one investigated here. This can vary a lot depending on starting pH and buffering capacity. Costs for addition of nitrogen source could probably be omitted, but this is normally not more than 1-2 SEK per ton of TMP. The extra need for oxygen in the treatment would not be more than some percent, but may be important if oxygen is limited. A substantial extra cost would be if the aeration volume has to be increased. According to the best results from the kinetic study, this would not be needed in an extended aeration activated plant with 2 days HRT and sludge concentrations of 2

  20. B cell markers in Ph1-positive acute lymphoblastic leukemia.

    Science.gov (United States)

    Alimena, G; De Rossi, G; Gastaldi, R; Guglielmi, C; Mandelli, F

    1980-01-01

    A case of acute lymphoblastic leukemia (ALL) where the blast cells had B cell markers and displayed the presence of a typical Ph1 chromosome, originated by a standard t (9;22) translocation, is reported. Cytological and clinical aspects during the entire course of the disease were consistent with the diagnosis of ALL. Evidence of differentiation along a well-defined lymphoid cell line in a Ph1-positive cell confirms the presence of the Ph1 chromosome in conditions other than chronic granulocytic leukemia and shows that it possibly does not occur in an exclusively undifferentiated totipotent stem cell.

  1. pH is the primary determinant of the bacterial community structure in agricultural soils impacted by polycyclic aromatic hydrocarbon pollution

    Science.gov (United States)

    Wu, Yucheng; Zeng, Jun; Zhu, Qinghe; Zhang, Zhenfa; Lin, Xiangui

    2017-01-01

    Acidification and pollution are two major threats to agricultural ecosystems; however, microbial community responses to co-existed soil acidification and pollution remain less explored. In this study, arable soils of broad pH (4.26–8.43) and polycyclic aromatic hydrocarbon (PAH) gradients (0.18–20.68 mg kg−1) were collected from vegetable farmlands. Bacterial community characteristics including abundance, diversity and composition were revealed by quantitative PCR and high-throughput sequencing. The bacterial 16S rRNA gene copies significantly correlated with soil carbon and nitrogen contents, suggesting the control of nutrients accessibility on bacterial abundance. The bacterial diversity was strongly related to soil pH, with higher diversity in neutral samples and lower in acidic samples. Soil pH was also identified by an ordination analysis as important factor shaping bacterial community composition. The relative abundances of some dominant phyla varied along the pH gradient, and the enrichment of a few phylotypes suggested their adaptation to low pH condition. In contrast, at the current pollution level, PAH showed marginal effects on soil bacterial community. Overall, these findings suggest pH was the primary determinant of bacterial community in these arable soils, indicative of a more substantial influence of acidification than PAH pollution on bacteria driven ecological processes. PMID:28051171

  2. pH is the primary determinant of the bacterial community structure in agricultural soils impacted by polycyclic aromatic hydrocarbon pollution

    Science.gov (United States)

    Wu, Yucheng; Zeng, Jun; Zhu, Qinghe; Zhang, Zhenfa; Lin, Xiangui

    2017-01-01

    Acidification and pollution are two major threats to agricultural ecosystems; however, microbial community responses to co-existed soil acidification and pollution remain less explored. In this study, arable soils of broad pH (4.26-8.43) and polycyclic aromatic hydrocarbon (PAH) gradients (0.18-20.68 mg kg-1) were collected from vegetable farmlands. Bacterial community characteristics including abundance, diversity and composition were revealed by quantitative PCR and high-throughput sequencing. The bacterial 16S rRNA gene copies significantly correlated with soil carbon and nitrogen contents, suggesting the control of nutrients accessibility on bacterial abundance. The bacterial diversity was strongly related to soil pH, with higher diversity in neutral samples and lower in acidic samples. Soil pH was also identified by an ordination analysis as important factor shaping bacterial community composition. The relative abundances of some dominant phyla varied along the pH gradient, and the enrichment of a few phylotypes suggested their adaptation to low pH condition. In contrast, at the current pollution level, PAH showed marginal effects on soil bacterial community. Overall, these findings suggest pH was the primary determinant of bacterial community in these arable soils, indicative of a more substantial influence of acidification than PAH pollution on bacteria driven ecological processes.

  3. Synthesis and new structure shaping mechanism of silica particles formed at high pH

    International Nuclear Information System (INIS)

    Zhang, Henan; Zhao, Yu; Akins, Daniel L.

    2012-01-01

    For the sol–gel synthesis of silica particles under high pH catalytic conditions (pH>12) in water/ethanol solvent, we have deduced that the competing dynamics of chemical etching and sol–gel process can explain the types of silica particles formed and their morphologies. We have demonstrated that emulsion droplets that are generated by adding tetraethyl orthosilicate (TEOS) to a water–ethanol solution serve as soft templates for hollow spherical silica (1–2 μm). And if the emulsion is converted by the sol–gel process, one finds that suspended solid silica spheres of diameter of ∼900 nm are formed. Moreover, several other factors are found to play fundamental roles in determining the final morphologies of silica particles, such as by variation of the pH (in our case, using OH – ) to a level where condensation dominates; by changing the volume ratios of water/ethanol; and using an emulsifier (specifically, CTAB) - Graphical abstract: “Local chemical etching” and sol–gel process have been proposed to interpret the control of morphologies of silica particles through varying initial pHs in syntheses. Highlights: ► Different initial pHs in our syntheses provides morphological control of silica particles. ► “Local chemical etching” and sol–gel process describes the formation of silica spheres. ► The formation of emulsions generates hollow silica particles.

  4. Pyrite oxidation at circumneutral pH

    Science.gov (United States)

    Moses, Carl O.; Herman, Janet S.

    1991-02-01

    Previous studies of pyrite oxidation kinetics have concentrated primarily on the reaction at low pH, where Fe(III) has been assumed to be the dominant oxidant. Studies at circumneutral pH, necessitated by effective pH buffering in some pyrite oxidation systems, have often implicitly assumed that the dominant oxidant must be dissolved oxygen (DO), owing to the diminished solubility of Fe(III). In fact, Fe(III)(aq) is an effective pyrite oxidant at circumneutral pH, but the reaction cannot be sustained in the absence of DO. The purpose of this experimental study was to ascertain the relative roles of Fe(III) and DO in pyrite oxidation at circumneutral pH. The rate of pyrite oxidation was first-order with respect to the ratio of surface area to solution volume. Direct determinations of both Fe(II) (aq)> and Fe(III) (aq) demonstrated a dramatic loss of Fe(II) from the solution phase in excess of the loss for which oxidation alone could account. Based on rate data, we have concluded that Fe(II) is adsorbed onto the pyrite surface. Furthermore, Fe(II) is preferred as an adsorbate to Fe(III), which we attribute to both electrostatic and acid-base selectivity. We also found that the rate of pyrite oxidation by either Fe(III) (aq) or DO is reduced in the presence of aqueous Fe(II), which leads us to conclude that, under most natural conditions, neither Fe(III) (aq) nor DO directly attacks the pyrite surface. The present evidence suggests a mechanism for pyrite oxidation that involves adsorbed Fe( II ) giving up electrons to DO and the resulting Fe(III) rapidly accepting electrons from the pyrite. The adsorbed Fe is, thus, cyclically oxidized and reduced, while it acts as a conduit for electrons traveling from pyrite to DO. Oxygen is transferred from the hydration sphere of the adsorbed Fe to pyrite S. The cycle of adsorbed Fe oxidation and reduction and the successive addition of oxygen to pyrite S continues until a stable sulfoxy species dissociates from the surface. Prior

  5. Metabolism of the intervertebral disc: effects of low levels of oxygen, glucose, and pH on rates of energy metabolism of bovine nucleus pulposus cells.

    Science.gov (United States)

    Bibby, Susan R S; Jones, Deborah A; Ripley, Ruth M; Urban, Jill P G

    2005-03-01

    In vitro measurements of metabolic rates of isolated bovine nucleus pulposus cells at varying levels of oxygen, glucose, and pH. To obtain quantitative information on the interactions between oxygen and glucose concentrations and pH, and the rates of oxygen and glucose consumption and lactic acid production, for disc nucleus cells. Disc cells depend on diffusion from blood vessels at the disc margins for supply of nutrients. Loss of supply is thought to lead to disc degeneration, but how loss of supply affects nutrient concentrations in the disc is not known; nutrient concentrations within discs can normally only be calculated, because concentration measurements are invasive. However, realistic predictions cannot be made until there are data from measurements of metabolic rates at conditions found in the disc in vivo, i.e., at low levels of oxygen, glucose, and pH. A metabolism chamber was designed to allow simultaneous recording of oxygen and glucose concentrations and of pH. These concentrations were measured electrochemically with custom-built glucose and oxygen sensors; lactic acid was measured biochemically. Bovine nucleus pulposus cells were isolated and inserted into the chamber, and simultaneous rates of oxygen and glucose consumption and of lactic acid production were measured over a range of glucose, oxygen, and pH levels. There were strong interactions between rates of metabolism and oxygen consumption and pH. At atmospheric oxygen levels, oxygen consumption rate at pH 6.2 was 32% of that at pH 7.4. The rate fell by 60% as oxygen concentration was decreased from 21 to 5% at pH 7.4, but only by 20% at pH 6.2. Similar interactions were seen for lactic acid production and glucose consumption rates; we found that glycolysis rates fell at low oxygen and glucose concentrations and low pH. Equations were derived that satisfactorily predict the effect of nutrient and metabolite concentrations on rates of lactic acid production rate and oxygen consumption. Disc

  6. Effect of complexing agents and pH on microstructure and tribological properties of Co-W coatings produced by double pulse electrodeposition

    International Nuclear Information System (INIS)

    Su Fenghua; Liu Cansen; Huang Ping

    2012-01-01

    The Co-W coatings were produced by double pulse electrodeposition from aqueous bath with cobalt sulphate and sodium tungstate. Effect of complexing agent and pH value in the plating bath on the microstructure, morphology and hardness of the electrodeposited Co-W coatings were investigated using an X-ray diffraction (XRD), scanning electron microscope (SEM) and a Vickers hardness tester, respectively. The friction and wear properties of the Co-W coatings deposited from different baths were evaluated with a ball-on-disk UMT-3MT tribometer. The correlation among the electrodepositing condition that varied with the complexing agent or pH value, the microstructure and the tribological properties of the deposited Co-W coatings were discussed. The results show that the complexing agent and pH value significantly affect the microstructure and tribological properties of the electrodeposited Co-W coatings. The sodium citrate is the best complexing agent to improve the tribological properties of the electrodeposited Co-W coatings at pH 6.0, followed by the sodium gluconate. The Co-W coatings electrodeposited from the near neutral bath can obtain better tribological properties than those deposited from strong acid or strong alkaline bath. The differences of the tribological properties for Co-W coatings from different baths were attributed to their different hardness, crystal structure and morphological characterizations, which can be optimized by the electrodepositing condition, i.e., the complexing agent and pH value in bath.

  7. Analysis on the influence of rainfall and mine water ratio against pH in East pit 3 West Banko coal mine

    Directory of Open Access Journals (Sweden)

    Rochyani Neny

    2017-01-01

    Full Text Available In the coal mining area, the pH of mine water is found tend to low and acids. In order to increase the pH, it is important to consider the treatment of acid mine drainage using lime, due the indicators of pollution. This work is focused on the influence of rainfall volume on the pH of acid mine drainage. This research conducted using a ratio of mine water and rainfall water that varies in the 9 (nine conditions, respectively: 1: 1, 1: 2, 1: 3, 1: 4 and 1: 5 and 5: 4, 5: 3 , 5: 2 and 5: 1. The results were then measured and tested with statistical analysis. The ratio of rainfall and mine water showed a significant effect on the pH. The higher of the rainfall lead to increase pH. This condition will affect the water neutralization process using lime where there are some possible differences on dose of lime needed to neutralized the acid mine drainage in the rainy season and dry season.

  8. Calibration of antimony-based electrode for ph monitoring into underground components of nuclear repositories

    International Nuclear Information System (INIS)

    Betelu, S.; Ignatiadis, I.

    2012-01-01

    unchanged with regard to pH variations, considering the RSD based on reproducibility. Whatever the ligand, no complex has competed with both the antimony hydrolysis and the oxygen depletion. The Sb electrode potential (E Sb ) varied linearly as a function of pH. Electrodes exhibit almost ideal Nernstian response. There was sufficient oxidation at the metal surface to ensure the equilibration conditions. Moreover, E Sb was somewhat affected by hysteresis. The potential of the platinum electrode (E Pt ) under atmospheric oxygen saturation is fixed by the O 2 /H 2 O redox couple. Under these conditions, EPt is governed by the PtO/Pt couple via PtO + 2H + + 2e - ↔ Pt + H 2 O with E PtO/Pt (mV/NHE) = 60.5 pH + 902. At the same pH and under aerobic conditions, a difference of about 700 mV (pH 0) is observed between EPt and E Sb . This difference is reduced to about 330 mV under anoxic conditions where O 2 /H 2 O is the predominant redox couple with a very low quantity of oxygen. Moreover, the slope of the E Sb -pH line remains the same regardless of the medium, which is very important, while the intercept giving the potential at pH = 0 differs by about 50 mV. This shows the dependence, although weak, of the Sb-based electrodes on the O 2 /H 2 O redox couple in the solution. This work provides information concerning the simultaneous but different behavior of two different electrodes under identical conditions and the same reference electrode. Knowledge of their electrochemical curves will allow us to draw potential-pH diagrams when observing and monitoring pH in the underground components of radioactive waste repositories where reference electrodes will not be used. Mono-crystalline Sb electrode appears to be appropriate for accurate measurements of pH in these conditions. Work is in progress to demonstrate the robustness of the Sb-electrode into COx over a long period

  9. pH tolerance of Daphnia pulex (leydig, emend. , richard)

    Energy Technology Data Exchange (ETDEWEB)

    Davis, P; Ozburn, G W

    1969-01-01

    The survival time and reproduction of female Daphnia pulex in solutions varying in pH have been observed. Dilute sodium hydroxide or sulfuric acid solutions were added to four different diluent waters: distilled water, aerated tap water, aerated and filtered tap water from an aquarium containing Dace minnows, and Mcintyre River water. D. Pulex (initially up to 72 hours old) survived for the duration of the experiment (32 hours) in river water within a pH range of 6.1 to 10.3; in aquarium water within a pH range of 4.3 to 10.4; only at pH 6.4 and pH 7.6 in distilled water; and in none of the solutions using aerated tap water. The dissolved oxygen content was measured at the beginning and end of every experiment and was found never to fall below 6.2 p.p.M. Those individuals which survived were cultured in the laboratory and parthenogenesis was observed at pH values between 7.0 and 8.7.

  10. Effects of pH on the crystallographic structure and magnetic properties of electrodeposited cobalt nanowires

    International Nuclear Information System (INIS)

    Zafar, N.; Shamaila, S.; Sharif, R.; Wali, H.; Naseem, S.; Riaz, S.; Khaleeq-ur-Rahman, M.

    2015-01-01

    Anodic aluminum oxide templates with pore diameter of 40 nm and inter pore separation of 100 nm are prepared by two step anodization in 0.3 M oxalic acid solution. These templates are used to fabricate dc-deposited Co nanowires at different pH values of acidic bath. Continuous and densely packed nanowires having length ∼8 µm are observed. The hcp configuration appeared at moderate and high pH whereas both fcc and hcp phases are observed at low pH. However the crystallinity distorted at high pH due to formation of polycrystalline structure of cobalt nanowires. Alignment of easy-axis of nanowires can be tailored by varying pH of solution. - Highlights: • Variation in the structure of dc deposited cobalt nanowires can be obtained by varying pH of acidic bath. • The hcp structure is stable at room temperature with low voltage deposition for electrodeposited Co nanowires. Co with fcc structure, is stable at temperatures above 422 °C or at pH<3 with high potential. • The hcp (100) plane is obtained with pH∼3.5 and (101) is stable at pH∼5.5 due to variation in temperature inside the pores with respect to the pH. • Alignment of easy-axis of nanowires can be tailored by varying pH of solution

  11. Paulette Gray, Ph.D.

    Science.gov (United States)

    Paulette S. Gray, Ph.D. is the Director for the Division of Extramural Activities (DEA). As the director of the division, she is responsible for the overall scientific, fiscal, and administrative management of the division, including broad strategic planning, development, implementation, and evaluation.

  12. pH in Action

    NARCIS (Netherlands)

    Tijskens, L.M.M.; Biekman, E.S.A.

    2001-01-01

    Based on fundamental chemical relations, well-established in chemical engineering and chemical technology over almost a century, the effects of pH in food and agricultural products will be deduced for different situations and processes. Based on simple equilibria and dissociation of water, salts,

  13. Neuronal pH regulation

    DEFF Research Database (Denmark)

    Vorstrup, S; Jensen, K E; Thomsen, C

    1989-01-01

    The intracellular pH in the brain was studied in six healthy volunteers before and immediately after the administration of 2 g of acetazolamide. Phosphorus-31 nuclear magnetic resonance spectroscopy by a 1.5 tesla whole-body scanner was used. The chemical shift between the inorganic phosphate...

  14. Improvement of the respiration efficiency of Lactococcus lactis by decreasing the culture pH.

    Science.gov (United States)

    Shi, Weijia; Li, Yu; Gao, Xueling; Fu, Ruiyan

    2016-03-01

    The growth characteristics and intracellular hemin concentrations of Lactococcus lactis grown under different culture pH and aeration conditions were examined to investigate the effect of culture pH on the respiration efficiency of L. lactis NZ9000 (pZN8148). Cell biomass and biomass yield of L. lactis grown with 4 μg hemin/ml and O2 were higher than those without aeration when the culture pH was controlled at 5-6.5. The culture pH affected the respiratory efficiency in the following order of pH: 5 > 5.5 > 6 > 6.5; the lag phase increased as the culture pH decreased. Hemin accumulation was sensitive to culture pH. Among the four pH conditions, pH 5.5 was optimal for hemin accumulation in the cells. The highest intracellular hemin level in L. lactis resting cells incubated at different pH saline levels (5-6.5) was at pH 5.5. The respiration efficiency of L. lactis under respiration-permissive conditions increases markedly as the culture pH decreases. These results may help develop high cell-density L. lactis cultures. Thus, this microorganism may be used for industrial applications.

  15. Influence of pH on optoelectronic properties of zinc sulphide thin films prepared using hydrothermal and spin coating method

    Science.gov (United States)

    Choudapur, V. H.; Bennal, A. S.; Raju, A. B.

    2018-04-01

    The ZnS nanomaterial is synthesized by hydrothermal method under optimized conditions using Zinc acetate and sodium sulphide as precursors. The Zinc Sulphide thin films are obtained by simple spin coating method with high optical transmittance. The prepared thin films are adhesive and uniform. The x-ray diffraction analysis showed that the films are polycrystalline in cubic phase with the preferred orientation along (111) direction. Current-voltage curves were recorded at room temperature using Keithley 617 programmable electrometer and conductivity is calculated for the film coated on ITO by two probe method. The pH of the solution is varied by using ammonia and hydrochloric acid. The comparative studies of effect of pH on the morphology, crystallanity and optoelectronic properties of the films are studied. It is observed that the pH of the solution has large influence on optoelectronic properties. The thin film prepared with neutral pH has higher crystallanity, bandgap and conductivity as compared to the samples prepared in acidic or basic solutions.

  16. Variation in gastric pH may determine kiwifruit's effect on functional GI disorder: an in vitro study.

    Science.gov (United States)

    Donaldson, Bruce; Rush, Elaine; Young, Owen; Winger, Ray

    2014-04-11

    Consumption of kiwifruit is reported to relieve symptoms of functional gastrointestinal (GI) disorder. The effect may be related to the proteases in kiwifruit. This in vitro study aimed to measure protein hydrolysis due to kiwifruit protease under gastric and duodenal conditions. A sequence of experiments incubated meat protein, with and without kiwifruit, with varying concentrations of pepsin and hydrochloric acid, at 37 °C for 60 min over the pH range 1.3-6.2 to simulate gastric digestion. Duodenal digestion was simulated by a further 120 min incubation at pH 6.4. Protein digestion efficiency was determined by comparing Kjeldahl nitrogen in pre- and post-digests. Where acid and pepsin concentrations were optimal for peptic digestion, hydrolysis was 80% effective and addition of kiwifruit made little difference. When pH was increased to 3.1 and pepsin activity reduced, hydrolysis decreased by 75%; addition of kiwifruit to this milieu more than doubled protein hydrolysis. This in vitro study has shown, when gastric pH is elevated, the addition of kiwifruit can double the rate of hydrolysis of meat protein. This novel finding supports the hypothesis that consumption of kiwifruit with a meal can increase the rate of protein hydrolysis, which may explain how kiwifruit relieves functional GI disorder.

  17. Variation in Gastric pH May Determine Kiwifruit’s Effect on Functional GI Disorder: An in Vitro Study

    Directory of Open Access Journals (Sweden)

    Bruce Donaldson

    2014-04-01

    Full Text Available Consumption of kiwifruit is reported to relieve symptoms of functional gastrointestinal (GI disorder. The effect may be related to the proteases in kiwifruit. This in vitro study aimed to measure protein hydrolysis due to kiwifruit protease under gastric and duodenal conditions. A sequence of experiments incubated meat protein, with and without kiwifruit, with varying concentrations of pepsin and hydrochloric acid, at 37 °C for 60 min over the pH range 1.3–6.2 to simulate gastric digestion. Duodenal digestion was simulated by a further 120 min incubation at pH 6.4. Protein digestion efficiency was determined by comparing Kjeldahl nitrogen in pre- and post-digests. Where acid and pepsin concentrations were optimal for peptic digestion, hydrolysis was 80% effective and addition of kiwifruit made little difference. When pH was increased to 3.1 and pepsin activity reduced, hydrolysis decreased by 75%; addition of kiwifruit to this milieu more than doubled protein hydrolysis. This in vitro study has shown, when gastric pH is elevated, the addition of kiwifruit can double the rate of hydrolysis of meat protein. This novel finding supports the hypothesis that consumption of kiwifruit with a meal can increase the rate of protein hydrolysis, which may explain how kiwifruit relieves functional GI disorder.

  18. Perturbation methods and the Melnikov functions for slowly varying oscillators

    International Nuclear Information System (INIS)

    Lakrad, Faouzi; Charafi, Moulay Mustapha

    2005-01-01

    A new approach to obtaining the Melnikov function for homoclinic orbits in slowly varying oscillators is proposed. The present method applies the Lindstedt-Poincare method to determine an approximation of homoclinic solutions. It is shown that the resultant Melnikov condition is the same as that obtained in the usual way involving distance functions in three dimensions by Wiggins and Holmes [Homoclinic orbits in slowly varying oscillators. SIAM J Math Anal 1987;18(3):612

  19. Bounds and asymptotics for orthogonal polynomials for varying weights

    CERN Document Server

    Levin, Eli

    2018-01-01

    This book establishes bounds and asymptotics under almost minimal conditions on the varying weights, and applies them to universality limits and entropy integrals.  Orthogonal polynomials associated with varying weights play a key role in analyzing random matrices and other topics.  This book will be of use to a wide community of mathematicians, physicists, and statisticians dealing with techniques of potential theory, orthogonal polynomials, approximation theory, as well as random matrices. .

  20. Industrial PhD report: Sustainable Innovation

    DEFF Research Database (Denmark)

    Olesen, Gitte Gylling Hammershøj

    2011-01-01

    Erhvervs PhD rapport udarbejdet i tilknytning til Erhvervs PhD kurset der er obligatorisk for Erhvervs PhD studerende. Rapporten omhandler relationer melllem den akademiske verden og industrien i sammenhæng med PhD projektet, betragtet og analyseret gennem teori om bæredygtig innovation....

  1. Intracellular pH in rat pancreatic ducts

    DEFF Research Database (Denmark)

    Novak, I; Hug, M; Greger, R

    1997-01-01

    In order to study the mechanism of H+ and HCO3- transport in a HCO3- secreting epithelium, pancreatic ducts, we have measured the intracellular pH (pHi) in this tissue using the pH sensitive probe BCECF. We found that exposures of ducts to solutions containing acetate/acetic acid or NH4+/NH3...... buffers (20 mmol/l) led to pHi changes in accordance with entry of lipid-soluble forms of the buffers, followed by back-regulation of pHi by duct cells. In another type of experiment, changes in extracellular pH of solutions containing HEPES or HCO3-/CO2 buffers led to significant changes in pHi that did....... Under some conditions, these exchangers can be invoked to regulate cell pH....

  2. Characterizing the variation in pH measurements with apheresis platelets.

    Science.gov (United States)

    Moroff, Gary; Seetharaman, Shalini; Kurtz, James; Wagner, Stephen J

    2011-11-01

    pH measurements of platelet (PLT) components remain a key parameter when assessing how storage and shipping conditions influence the retention of PLT properties. Studies were conducted to characterize variations in pH measured with two pH meters and a blood gas analyzer. Samples were obtained from apheresis PLT units that were stored with or without continuous agitation to measure a range of pH values. pH values were determined with pH meters at room temperature (20-24°C) upon placing of samples in 5-mL sterile polypropylene tubes and with the blood gas analyzer at 37°C upon injection of identical samples, with conversion to 22°C. The calculated coefficient of variation (%CV) of pH measurements using pH meters (n = 10) was 0.43% or less. The %CV values were comparable with different samples having pH values ranging from 6.0 to 7.4. The %CV levels with the blood gas analyzer were comparable to those observed with the pH meters. The difference in the mean pH values for the two pH meters was no greater than 0.10 units, with 9 of 10 samples having differences in values of 0.05 or less; however, greater differences of values (0.1 to 0.2) were observed between pH measured using the blood gas analyzer and pH meters. Our data show good precision and comparability of pH measurements with two pH meters. Differences in pH values were greater on comparison of the blood gas analyzer with the pH meters. © 2011 American Association of Blood Banks.

  3. A varying-α brane world cosmology

    International Nuclear Information System (INIS)

    Youm, Donam

    2001-08-01

    We study the brane world cosmology in the RS2 model where the electric charge varies with time in the manner described by the varying fine-structure constant theory of Bekenstein. We map such varying electric charge cosmology to the dual variable-speed-of-light cosmology by changing system of units. We comment on cosmological implications for such cosmological models. (author)

  4. Biogenic precipitation of manganese oxides and enrichment of heavy metals at acidic soil pH

    Science.gov (United States)

    Mayanna, Sathish; Peacock, Caroline L.; Schäffner, Franziska; Grawunder, Anja; Merten, Dirk; Kothe, Erika; Büchel, Georg

    2014-05-01

    The precipitation of biogenic Mn oxides at acidic pH is rarely reported and poorly understood, compared to biogenic Mn oxide precipitation at near neutral conditions. Here we identified and investigated the precipitation of biogenic Mn oxides in acidic soil, and studied their role in the retention of heavy metals, at the former uranium mining site of Ronneburg, Germany. The site is characterized by acidic pH, low carbon content and high heavy metal loads including rare earth elements. Specifically, the Mn oxides were present in layers identified by detailed soil profiling and within these layers pH varied from 4.7 to 5.1, Eh varied from 640 to 660 mV and there were enriched total metal contents for Ba, Ni, Co, Cd and Zn in addition to high Mn levels. Using electron microprobe analysis, synchrotron X-ray diffraction and X-ray absorption spectroscopy, we identified poorly crystalline birnessite (δ-MnO2) as the dominant Mn oxide in the Mn layers, present as coatings covering and cementing quartz grains. With geochemical modelling we found that the environmental conditions at the site were not favourable for chemical oxidation of Mn(II), and thus we performed 16S rDNA sequencing to isolate the bacterial strains present in the Mn layers. Bacterial phyla present in the Mn layers belonged to Firmicutes, Actinobacteria and Proteobacteria, and from these phyla we isolated six strains of Mn(II) oxidizing bacteria and confirmed their ability to oxidise Mn(II) in the laboratory. The biogenic Mn oxide layers act as a sink for metals and the bioavailability of these metals was much lower in the Mn layers than in adjacent layers, reflecting their preferential sorption to the biogenic Mn oxide. In this presentation we will report our findings, concluding that the formation of natural biogenic poorly crystalline birnessite can occur at acidic pH, resulting in the formation of a biogeochemical barrier which, in turn, can control the mobility and bioavailability of heavy metals in

  5. Pressure fluctuations on the bed of surge tank at the H.P. Zimapan, Hgo., with different arrangements studied on hydraulic model, with the lowest operation conditions; Fluctuaciones de presion en la base del pozo de oscilacion del P.H. Zimapan Hgo., con diferentes arreglos estudiados en modelo hidraulico ante las condiciones minimas de operacion

    Energy Technology Data Exchange (ETDEWEB)

    Marengo Mogollon, H. [Facultad de Ingenieria, Universidad Nacional Autonoma de Mexico (Mexico)]. E-mail: humberto.marengo@cfe.gob.mx; Ochoa Alvarez, F.J.; Cortes Cortes, C. [Comision Federal de Electricidad (Mexico)]. E-mail: federico.ochoa@cfe.gob.mx; carlos.cortes01@cfe.gob.mx

    2009-10-15

    In this paper, the pressure fluctuations of the surge tank in the Zimapan Hydroelectric Project are compared in a hydraulic model. The shaft is located lateral, over the conduction tunnel and in the simple form (permitting the tunnel entering the shaft); with and without orifice plates taking into account the demand and supply condition of energy with the minimum level of water of the conduction. It was determined the hydraulic efficiency and it was found that it was the best constructive option. [Spanish] En este articulo se comparan las fluctuaciones de presion en el pozo de oscilacion del P.H. Zimapan, Hgo., Mexico las cuales fueron estudiadas en modelo hidraulico al considerar dicho pozo ubicado en diferentes posiciones; lateralmente y sobre el eje de la conduccion; pozo simple y con tuberia de conexion; con y sin placa de orificio, para maniobras de rechazo y demanda de carga de las turbinas de generacion con el nivel del agua correspondiente al NAMINO. Se determino la eficiencia hidraulica comparandola con las otras opciones encontrandose que la mejor opcion para el funcionamiento hidraulico es el pozo lateral, que ademas permite optimizar el procedimiento constructivo.

  6. Measurement of pH, exudate composition and temperature in wound healing: a systematic review.

    Science.gov (United States)

    Power, G; Moore, Z; O'Connor, T

    2017-07-02

    To assess the potential of measurements of pH, exudate composition and temperature in wounds to predict healing outcomes and to identify the methods that are employed to measure them. A systematic review based on the outcomes of a search strategy of quantitative primary research published in the English language was conducted. Inclusion criteria limited studies to those involving in vivo and human participants with an existing or intentionally provoked wound, defined as 'a break in the epithelial integrity of the skin', and excluded in vitro and animal studies. Data synthesis and analysis was performed using structured narrative summaries of each included study arranged by concept, pH, exudate composition and temperature. The Evidence Based Literature (EBL) Critical Appraisal Checklist was implemented to appraise the quality of the included studies. A total of 23 studies, three for pH (mean quality score 54.48%), 12 for exudate composition (mean quality score 46.54%) and eight for temperature (mean quality score 36.66%), were assessed as eligible for inclusion in this review. Findings suggest that reduced pH levels in wounds, from alkaline towards acidic, are associated with improvements in wound condition. Metalloproteinase-9 (MMP-9), matrix metalloproteinase-2 (MMP-2), tissue inhibitor of metalloproteinase (TIMP), neutrophil elastase (NE) and albumin, in descending order, were the most frequently measured analytes in wounds. MMP-9 emerged as the analyte which offers the most potential as a biomarker of wound healing, with elevated levels observed in acute or non-healing wounds and decreasing levels in wounds progressing in healing. Combined measures of different exudate components, such as MMP/TIMP ratios, also appeared to offer substantial potential to indicate wound healing. Finally, temperature measurements are highest in non-healing, worsening or acute wounds and decrease as wounds progress towards healing. Methods used to measure pH, exudate composition and

  7. Alkaline pH sensor molecules.

    Science.gov (United States)

    Murayama, Takashi; Maruyama, Ichiro N

    2015-11-01

    Animals can survive only within a narrow pH range. This requires continual monitoring of environmental and body-fluid pH. Although a variety of acidic pH sensor molecules have been reported, alkaline pH sensor function is not well understood. This Review describes neuronal alkaline pH sensors, grouped according to whether they monitor extracellular or intracellular alkaline pH. Extracellular sensors include the receptor-type guanylyl cyclase, the insulin receptor-related receptor, ligand-gated Cl- channels, connexin hemichannels, two-pore-domain K+ channels, and transient receptor potential (TRP) channels. Intracellular sensors include TRP channels and gap junction channels. Identification of molecular mechanisms underlying alkaline pH sensing is crucial for understanding how animals respond to environmental alkaline pH and how body-fluid pH is maintained within a narrow range. © 2015 Wiley Periodicals, Inc.

  8. Nanomechanical DNA Origami pH Sensors

    Directory of Open Access Journals (Sweden)

    Akinori Kuzuya

    2014-10-01

    Full Text Available Single-molecule pH sensors have been developed by utilizing molecular imaging of pH-responsive shape transition of nanomechanical DNA origami devices with atomic force microscopy (AFM. Short DNA fragments that can form i-motifs were introduced to nanomechanical DNA origami devices with pliers-like shape (DNA Origami Pliers, which consist of two levers of 170-nm long and 20-nm wide connected at a Holliday-junction fulcrum. DNA Origami Pliers can be observed as in three distinct forms; cross, antiparallel and parallel forms, and cross form is the dominant species when no additional interaction is introduced to DNA Origami Pliers. Introduction of nine pairs of 12-mer sequence (5'-AACCCCAACCCC-3', which dimerize into i-motif quadruplexes upon protonation of cytosine, drives transition of DNA Origami Pliers from open cross form into closed parallel form under acidic conditions. Such pH-dependent transition was clearly imaged on mica in molecular resolution by AFM, showing potential application of the system to single-molecular pH sensors.

  9. Nanomechanical DNA origami pH sensors.

    Science.gov (United States)

    Kuzuya, Akinori; Watanabe, Ryosuke; Yamanaka, Yusei; Tamaki, Takuya; Kaino, Masafumi; Ohya, Yuichi

    2014-10-16

    Single-molecule pH sensors have been developed by utilizing molecular imaging of pH-responsive shape transition of nanomechanical DNA origami devices with atomic force microscopy (AFM). Short DNA fragments that can form i-motifs were introduced to nanomechanical DNA origami devices with pliers-like shape (DNA Origami Pliers), which consist of two levers of 170-nm long and 20-nm wide connected at a Holliday-junction fulcrum. DNA Origami Pliers can be observed as in three distinct forms; cross, antiparallel and parallel forms, and cross form is the dominant species when no additional interaction is introduced to DNA Origami Pliers. Introduction of nine pairs of 12-mer sequence (5'-AACCCCAACCCC-3'), which dimerize into i-motif quadruplexes upon protonation of cytosine, drives transition of DNA Origami Pliers from open cross form into closed parallel form under acidic conditions. Such pH-dependent transition was clearly imaged on mica in molecular resolution by AFM, showing potential application of the system to single-molecular pH sensors.

  10. NH4+-NH3 removal from simulated wastewater using UV-TiO2 photocatalysis: effect of co-pollutants and pH.

    Science.gov (United States)

    Vohra, M S; Selimuzzaman, S M; Al-Suwaiyan, M S

    2010-05-01

    The main objective of the present study was to investigate the efficiency of titanium dioxide (TiO2) assisted photocatalytic degradation (PCD) process for the removal of ammonium-ammonia (NH4(+)-NH3) from the aqueous phase and in the presence of co-pollutants thiosulfate (S2O3(2-)) and p-cresol (C6H4CH3OH) under varying mixed conditions. For the NH4(+)-NH3 only PCD experiments, results showed higher NH4 -NH3 removal at pH 12 compared to pH 7 and 10. For the binary NH4(+)-NH3/S2O3(2-) studies the respective results indicated a significant lowering in NH4(+)-NH3 PCD in the presence of S2O32- at pH 7/12 whereas at pH 10 a marked increase in NH4(+)-NH3 removal transpired. A similar trend was noted for the p-cresol/NH4(+)-NH3 binary system. Comparing findings from the binary (NH4(+)-NH3/S2O3(2-) and p-cresol/NH4(+)-NH3) and tertiary (NH4(+)-NH3/S2O3(2-)/p-cresol) systems, at pH 10, showed fastest NH4(+)-NH3 removal transpiring for the tertiary system as compared to the binary systems, whereas both the binary systems indicated comparable NH4(+)-NH3 removal trends. The respective details have been discussed.

  11. Distribution of tetracycline resistance genes in anaerobic treatment of waste sludge: The role of pH in regulating tetracycline resistant bacteria and horizontal gene transfer.

    Science.gov (United States)

    Huang, Haining; Chen, Yinguang; Zheng, Xiong; Su, Yinglong; Wan, Rui; Yang, Shouye

    2016-10-01

    Although pH value has been widely regarded as an important factor that affects resource recovery of waste sludge, the potential influence of diverse pHs on the distribution of tetracycline resistance genes (TRGs) during sludge anaerobic treatment is largely unknown. Here we reported that in the range of pH 4-10, 0.58-1.18 log unit increase of target TRGs was observed at pH 4, compared with that at pH 7, while 0.70-1.31 log unit further removal were obtained at pH 10. Mechanism study revealed that varied pHs not only altered the community structures of tetracycline resistant bacteria (TRB), but also changed their relative abundances, benefitting the propagation (acidic pHs) or attenuation (alkaline pHs) of TRB. Further investigation indicated that the amount and gene-possessing abilities of key genetic vectors for horizontal TRGs transfer were greatly promoted at acidic pHs but restricted under alkaline conditions. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. A reciprocal Wald theorem for varying gravitational function

    International Nuclear Information System (INIS)

    Fay, Stephane

    2004-01-01

    We study when a cosmological constant is a natural issue if it is mimicked by the potential of a massive Hyperextended Scalar Tensor theory with a perfect fluid for Bianchi type I and V models. We then deduce a reciprocal Wald theorem giving the conditions such that the potential tends to a non vanishing constant when the gravitational function varies. We also get the conditions allowing the potential to vanish or diverge. (orig.)

  13. Identification of a molecular pH sensor in coral.

    Science.gov (United States)

    Barott, Katie L; Barron, Megan E; Tresguerres, Martin

    2017-11-15

    Maintaining stable intracellular pH (pHi) is essential for homeostasis, and requires the ability to both sense pH changes that may result from internal and external sources, and to regulate downstream compensatory pH pathways. Here we identified the cAMP-producing enzyme soluble adenylyl cyclase (sAC) as the first molecular pH sensor in corals. sAC protein was detected throughout coral tissues, including those involved in symbiosis and calcification. Application of a sAC-specific inhibitor caused significant and reversible pHi acidosis in isolated coral cells under both dark and light conditions, indicating sAC is essential for sensing and regulating pHi perturbations caused by respiration and photosynthesis. Furthermore, pHi regulation during external acidification was also dependent on sAC activity. Thus, sAC is a sensor and regulator of pH disturbances from both metabolic and external origin in corals. Since sAC is present in all coral cell types, and the cAMP pathway can regulate virtually every aspect of cell physiology through post-translational modifications of proteins, sAC is likely to trigger multiple homeostatic mechanisms in response to pH disturbances. This is also the first evidence that sAC modulates pHi in any non-mammalian animal. Since corals are basal metazoans, our results indicate this function is evolutionarily conserved across animals. © 2017 The Author(s).

  14. Electrochemical Impedance Spectroscopic Analysis of RuO2 Based Thick Film pH Sensors

    International Nuclear Information System (INIS)

    Manjakkal, Libu; Djurdjic, Elvira; Cvejin, Katarina; Kulawik, Jan; Zaraska, Krzysztof; Szwagierczak, Dorota

    2015-01-01

    The conductimetric interdigitated thick film pH sensors based on RuO 2 were fabricated and their electrochemical reactions with solutions of different pH values were studied by electrochemical impedance spectroscopy (EIS) technique. The microstructural properties and composition of the sensitive films were examined by scanning electron microscopy, X-ray energy dispersive spectroscopy and Raman spectroscopy. The EIS analysis of the sensor was carried out in the frequency range 10 mHz–2 MHz for pH values of test solutions 2–12. The electrical parameters of the sensor were found to vary with changing pH. The conductance and capacitance of the film were distinctly dependent on pH in the low frequency range. The Nyquist and Bode plots derived from the impedance data for the metal oxide thick film pH sensor provided information about the underlying electrochemical reactions

  15. Intracellular pH and 42.00 C heat response of CHO cells cultured at pH 6.6

    International Nuclear Information System (INIS)

    Cook, J.A.; Fox, M.H.

    1987-01-01

    The authors previously reported that cells under chronic low pH (6.6) conditions have altered thermotolerance. They further characterized both the doubling time (t/sub d/) and the internal pH (pH/sub 1/) of CHO cells continuously cultured at pH 6.6 for times greater than one year. The following differences were noted: 1) A t/sub d/ of 16 hr compared to a t/sub d/ of 12 hr for cells at normal pH (7.3) and a t/sub d/ of 25 hr for the acute low pH cells (pH = 6.6; incubation time = 4 hr). 2) A pH/sub i/ 0.1-0.15 pH units > normal cells and 0.3 pH units > acute low pH cells. 3) Survival at 42.0 0 C which differed from both normal and acute low pH cells. The chronic culture was still quite sensitive to 42.0 0 C treatments during the first 5 hr, but developed tolerance at a higher level than cells under acute low pH conditions. The pH/sub i/ of the chronic culture responded to 42.0 0 C heating in a manner similar to that for acute low pH cells. Whether this culture represents a normal response to long term low pH exposure, or was the response of a mutant population is at the present unknown

  16. The pH of commonly available soaps, liquid cleansers, detergents and alcohol gels.

    Science.gov (United States)

    Boonchai, Waranya; Iamtharachai, Pacharee

    2010-01-01

    The hydrogen ion concentration (pH) of a cleanser certainly has an impact on skin condition. Dermatologists always need to recommend a cleanser to patients with hand dermatitis or sensitive skin; particularly during the outbreak of swine (AH1N1 virus) influenza, frequent hand washing and alcohol gel cleansing were greatly recommended. The purpose of this study was to evaluate the pH of various commonly available cleansers and alcohol gels on the market to assess patient comfort in using such products and to make good recommendations to our patients. Multiple brands of liquid cleansers, dishwashing liquids, soaps, laundry detergents, and alcohol gels commonly available on the market were assessed for pH by using a pH meter and pH-indicator strips. The pH assessment imitated real-life conditions by diluting each cleanser with tap water and then comparing the changed pH. The pH levels of liquid cleansers, dishwashing liquids, a beauty bar, and alcohol gels were acidic to neutral and compatible with normal skin pH. Most bar soaps, baby soaps, and powdered laundry detergents had a pH in the alkali range. The pH of concentrated cleansers was slightly different from that of their dissolved forms. Regarding the antiseptic property and pH of the cleansers, alcohol gels with moisturizers appeared to be the best hand cleansers to recommend to our patients.

  17. Fetal scalp pH testing

    Science.gov (United States)

    Fetal scalp blood; Scalp pH testing; Fetal blood testing - scalp; Fetal distress - fetal scalp testing; Labor - fetal scalp testing ... a baby. In these cases, testing the scalp pH can help the doctor decide whether the fetus ...

  18. Acid loading test (pH)

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/003615.htm Acid loading test (pH) To use the sharing features on this page, please enable JavaScript. The acid loading test (pH) measures the ability of the ...

  19. Variation of iron redox kinetics and its relation with molecular composition of standard humic substances at circumneutral pH.

    Science.gov (United States)

    Lee, Ying Ping; Fujii, Manabu; Kikuchi, Tetsuro; Terao, Koumei; Yoshimura, Chihiro

    2017-01-01

    Oxidation and reduction kinetics of iron (Fe) and proportion of steady-state Fe(II) concentration relative to total dissolved Fe (steady-state Fe(II) fraction) were investigated in the presence of various types of standard humic substances (HS) with particular emphasis on the photochemical and thermal reduction of Fe(III) and oxidation of Fe(II) by dissolved oxygen (O2) and hydrogen peroxide (H2O2) at circumneutral pH (pH 7-8). Rates of Fe(III) reduction were spectrophotometrically determined by a ferrozine method under the simulated sunlight and dark conditions, whereas rates of Fe(II) oxidation were examined in air-saturated solution using luminol chemiluminescence technique. The reduction and oxidation rate constants were determined to substantially vary depending on the type of HS. For example, the first-order rate constants varied by up to 10-fold for photochemical reduction and 7-fold for thermal reduction. The degree of variation in Fe(II) oxidation was larger for the H2O2-mediated reaction compared to the O2-mediated reaction (e.g., 15- and 3-fold changes for the former and latter reactions, respectively, at pH 8). The steady-state Fe(II) fraction under the simulated sunlight indicated that the Fe(II) fraction varies by up to 12-fold. The correlation analysis indicated that variation of Fe(II) oxidation is significantly associated with aliphatic content of HS, suggesting that Fe(II) complexation by aliphatic components accelerates Fe(II) oxidation. The reduction rate constant and steady-state Fe(II) fractions in the presence of sunlight had relatively strong positive relations with free radical content of HS, possibly due to the reductive property of radical semiquinone in HS. Overall, the findings in this study indicated that the Fe reduction and oxidation kinetics and resultant Fe(II) formation are substantially influenced by chemical properties of HS.

  20. Trends in MD/PhD Graduates Entering Psychiatry: Assessing the Physician-Scientist Pipeline.

    Science.gov (United States)

    Arbuckle, Melissa R; Luo, Sean X; Pincus, Harold Alan; Gordon, Joshua A; Chung, Joyce Y; Chavez, Mark; Oquendo, Maria A

    2018-06-01

    The goal of this study was to identify trends in MD/PhD graduates entering psychiatry, to compare these trends with other specialties, and to review strategies for enhancing the physician-scientist pipeline. Data on 226,588 medical students graduating from Liaison Committee on Medical Education accredited programs between 1999 and 2012 (6626 MD/PhDs) were used to evaluate the number, percentage, and proportion of MD/PhDs entering psychiatry in comparison with other specialties (neurology, neurosurgery, internal medicine, family medicine, and radiation oncology). Linear regression and multiple linear regression determined whether these values increased over time and varied by sex. Over 14 years, an average of 18 MD/PhDs (range 13-29) enrolled in psychiatry each year. The number of MD/PhDs going into psychiatry significantly increased, although these gains were modest (less than one additional MD/PhD per year). The proportion of students entering psychiatry who were MD/PhDs varied between 2.9 and 5.9 per 100 residents, with no significant change over time. There was also no change in the percentage of MD/PhDs entering psychiatry from among all MD/PhD graduates. The rate of increase in the number of MD/PhDs going into psychiatry did not differ significantly from other specialties except for family medicine, which is decreasing. The rate of MD/PhDs going into psychiatry was higher for women, suggesting closure of the sex gap in 17 years. Despite the increase in the number of MD/PhDs entering psychiatry, these numbers remain low. Expanding the cohort of physician-scientists dedicated to translational research in psychiatry will require a multipronged approach.

  1. pH sensor calibration procedure

    OpenAIRE

    Artero Delgado, Carola; Nogueras Cervera, Marc; Manuel Lázaro, Antonio; Prat Tasias, Jordi; Prat Farran, Joana d'Arc

    2013-01-01

    This paper describes the calibration of pH sensor located at the OBSEA marine Observatory. This instrument is based on an industrial pH electrode that is connected to a CTD instrument (Conductivity, Temperature, and Depth ). The calibration of the pH sensor has been done using a high precision spectrophotometer pH meter from Institute of Marine Sciences (ICM), and in this way it has been obtained a numerical function for the p H sensor propor...

  2. Low pH Enhances the Action of Maximin H5 against Staphylococcus aureus and Helps Mediate Lysylated Phosphatidylglycerol-Induced Resistance.

    Science.gov (United States)

    Dennison, Sarah R; Morton, Leslie Hg; Harris, Frederick; Phoenix, David A

    2016-07-12

    Maximin H5 (MH5) is an amphibian antimicrobial peptide specifically targeting Staphylococcus aureus. At pH 6, the peptide showed an improved ability to penetrate (ΔΠ = 6.2 mN m(-1)) and lyse (lysis = 48%) Staphylococcus aureus membrane mimics, which incorporated physiological levels of lysylated phosphatidylglycerol (Lys-PG, 60%), compared to that at pH 7 (ΔΠ = 5.6 mN m(-1) and lysis = 40% at pH 7) where levels of Lys-PG are lower (40%). The peptide therefore appears to have optimal function at pH levels known to be optimal for the organism's growth. MH5 killed S. aureus (minimum inhibitory concentration of 90 μM) via membranolytic mechanisms that involved the stabilization of α-helical structure (approximately 45-50%) and showed similarities to the "Carpet" mechanism based on its ability to increase the rigidity (Cs(-1) = 109.94 mN m(-1)) and thermodynamic stability (ΔGmix = -3.0) of physiologically relevant S. aureus membrane mimics at pH 6. On the basis of theoretical analysis, this mechanism might involve the use of a tilted peptide structure, and efficacy was noted to vary inversely with the Lys-PG content of S. aureus membrane mimics for each pH studied (R(2) ∼ 0.97), which led to the suggestion that under biologically relevant conditions, low pH helps mediate Lys-PG-induced resistance in S. aureus to MH5 antibacterial action. The peptide showed a lack of hemolytic activity (<2% hemolysis) and merits further investigation as a potential template for development as an antistaphylococcal agent in medically and biotechnically relevant areas.

  3. Process model for ammonia volatilization from anaerobic swine lagoons incorporating varying wind speeds and biogas bubbling

    Science.gov (United States)

    Ammonia volatilization from treatment lagoons varies widely with the total ammonia concentration, pH, temperature, suspended solids, atmospheric ammonia concentration above the water surface, and wind speed. Ammonia emissions were estimated with a process-based mechanistic model integrating ammonia ...

  4. The relationship between mantle pH and the deep nitrogen cycle

    Science.gov (United States)

    Mikhail, Sami; Barry, Peter H.; Sverjensky, Dimitri A.

    2017-07-01

    Nitrogen is distributed throughout all terrestrial geological reservoirs (i.e., the crust, mantle, and core), which are in a constant state of disequilibrium due to metabolic factors at Earth's surface, chemical weathering, diffusion, and deep N fluxes imposed by plate tectonics. However, the behavior of nitrogen during subduction is the subject of ongoing debate. There is a general consensus that during the crystallization of minerals from melts, monatomic nitrogen behaves like argon (highly incompatible) and ammonium behaves like potassium and rubidium (which are relatively less incompatible). Therefore, the behavior of nitrogen is fundamentally underpinned by its chemical speciation. In aqueous fluids, the controlling factor which determines if nitrogen is molecular (N2) or ammonic (inclusive of both NH4+ and NH30) is oxygen fugacity, whereas pH designates if ammonic nitrogen is NH4+ or NH30. Therefore, to address the speciation of nitrogen at high pressures and temperatures, one must also consider pH at the respective pressure-temperature conditions. To accomplish this goal we have used the Deep Earth Water Model (DEW) to calculate the activities of aqueous nitrogen from 1-5 GPa and 600-1000 °C in equilibrium with a model eclogite-facies mineral assemblage of jadeite + kyanite + quartz/coesite (metasediment), jadeite + pyrope + talc + quartz/coesite (metamorphosed mafic rocks), and carbonaceous eclogite (metamorphosed mafic rocks + elemental carbon). We then compare these data with previously published data for the speciation of aqueous nitrogen across these respective P-T conditions in equilibrium with a model peridotite mineral assemblage (Mikhail and Sverjensky, 2014). In addition, we have carried out full aqueous speciation and solubility calculations for the more complex fluids in equilibrium with jadeite + pyrope + kyanite + diamond, and for fluids in equilibrium with forsterite + enstatite + pyrope + diamond. Our results show that the pH of the fluid is

  5. Complexing Agents and pH Influence on Chemical Durability of Type I Molded Glass Containers.

    Science.gov (United States)

    Biavati, Alberto; Poncini, Michele; Ferrarini, Arianna; Favaro, Nicola; Scarpa, Martina; Vallotto, Marta

    2017-01-01

    . To prevent such situations, pharmaceutical and biopharmaceutical manufacturers need to understand the reasons for accelerate surface glass corrosion mainly in the case of injectables.Some drugs can contain active components with known ability to corrode glass silica networks. Sometimes these ingredients are dissolved in an alkaline medium that dramatically increases the glass corrosion and potentially causes the issue. As this action is strongly affected by time and temperature, flaking may become visible only after a long storage time. The purpose of this investigation is to verify the borosilicate glass chemical durability during controlled conditions of time and temperature when in contact with testing solutions containing different complexing agents by varying the pH. Si concentration in the extract solution is taken as an index of glass dissolution during constant autoclaving conditions for 1 h at 121 °C, which simulates approximately five years of contact at room temperature.Acetate, citrate, ethylenediaminetetraacetic acid (EDTA), phosphate, and glutarate 0.048 M or 0.024 M solutions were used at increasing pH from 5.5 to 9.0. The chemical durability of two borosilicate tubing glass vials of different glass compositions were compared with the molded one in the worst attack conditions by citric acid. Even if no delamination issue has been experienced by this study in type I molded and tubing containers, the conclusions developed can provide pharmaceutical manufacturers with useful information to prevent glass delamination risk in their processes. © PDA, Inc. 2017.

  6. Spacetime-varying couplings and Lorentz violation

    International Nuclear Information System (INIS)

    Kostelecky, V. Alan; Lehnert, Ralf; Perry, Malcolm J.

    2003-01-01

    Spacetime-varying coupling constants can be associated with violations of local Lorentz invariance and CPT symmetry. An analytical supergravity cosmology with a time-varying fine-structure constant provides an explicit example. Estimates are made for some experimental constraints

  7. Sorption of neptunium(V) on opalinus clay under aerobic/anaerobic conditions

    International Nuclear Information System (INIS)

    Froehlich, D.R.; Amayri, S.; Drebert, J.; Reich, T.

    2011-01-01

    The interaction between neptunium(V) and a natural argillaceous rock (Opalinus Clay (OPA), Mont Terri, Switzerland) has been investigated in batch sorption experiments by varying pH (6-10), Np(V) concentration (10 -12 -10 -4 M), solid-to-liquid ratio (2-20 g/L), and partial pressure of CO 2 (10 -3.5 and 10 -2.3 atm) under aerobic/anaerobic conditions in saturated calcite solution. All batch experiments were carried out using well characterized aerobic and anaerobic dry powders of OPA. The results show a great influence of pH on Np(V) sorption. Under aerobic conditions sorption increases with increasing pH until maximum sorption is reached between pH 8-9. At pH > 9 sorption decreases due to the formation of negatively charged Np(V)-carbonate complexes. By increasing p CO 2 from 10 -3.5 to 10 -2.3 atm, the sorption edge is shifted ∼ 0.5 units to lower pH values. Under anaerobic conditions stronger sorption of 8 x 10 -6 M Np(V) was found, possibly due to partial reduction of Np(V) to Np(IV). The sorption of 8 x 10 -6 M Np(V) under aerobic conditions at pH 8.2 in saturated calcite solution increases continuously with increasing solid-to-liquid ratio of OPA in the range of 2-20 g/L with a constant K d value of 126 ± 13 L/kg. The sorption isotherm was measured over seven orders of magnitude in Np(V) concentration using 239 Np as tracer. The sorption isotherm could be divided in a part of linear sorption behaviour between 10 -13 -10 -9 M Np(V) and non-linear behaviour in the range of 10 -9 -10 -4 M Np(V). (orig.)

  8. Stress corrosion cracking properties of 15-5PH steel

    Science.gov (United States)

    Rosa, Ferdinand

    1993-01-01

    Unexpected occurrence of failures, due to stress corrosion cracking (SCC) of structural components, indicate a need for improved characterization of materials and more advanced analytical procedures for reliably predicting structures performance. Accordingly, the purpose of this study was to determine the stress corrosion susceptibility of 15-5PH steel over a wide range of applied strain rates in a highly corrosive environment. The selected environment for this investigation was a highly acidified sodium chloride (NaCl) aqueous solution. The selected alloy for the study was a 15-5PH steel in the H900 condition. The slow strain rate technique was selected to test the metals specimens.

  9. Torsional Arming of Thiomannosyl Donors & Conformational Control of Hexahydropyridazines via pH

    DEFF Research Database (Denmark)

    Olsen, Jacob Ingemar

    The overall objective of the research presented in this PhD thesis was to investigate torsional arming of thiogalacto- and thiomannosyl donors (part 1) and to investigate the possible synthesis and attachment of a pH regulated conformational switch to an α-cyclodextrin (part 2). Part 1: It is well...... demonstrated their ability to change conformation under different conditions. These conformational changes are connected to various intramolecular interactions and can to some extent, be controlled by pH (Chapter 3). Fusing these conformationally labile compounds to the rim of a cyclodextrin would create...... compounds that could release molecules at a specified change in pH conditions. To investigate this, four hexahydropyridazines were synthesized and investigated for their pH induced conformational change (Chapter 4). Out of the four compounds, one revealed to flip between two conformations depending on pH...

  10. Iminoboronate Formation Leads to Fast and Reversible Conjugation Chemistry of α-Nucleophiles at Neutral pH.

    Science.gov (United States)

    Bandyopadhyay, Anupam; Gao, Jianmin

    2015-10-12

    Bioorthogonal reactions that are fast and reversible under physiological conditions are in high demand for biological applications. Herein, it is shown that an ortho boronic acid substituent makes aryl ketones rapidly conjugate with α-nucleophiles at neutral pH. Specifically, 2-acetylphenylboronic acid and derivatives were found to conjugate with phenylhydrazine with rate constants of 10(2) to 10(3) M(-1) s(-1) , comparable to the fastest bioorthogonal conjugations known to date. (11) B NMR analysis revealed the varied extent of iminoboronate formation of the conjugates, in which the imine nitrogen forms a dative bond with boron. The iminoboronate formation activates the imines for hydrolysis and exchange, rendering these oxime/hydrazone conjugations reversible and dynamic under physiological conditions. The fast and dynamic nature of the iminoboronate chemistry should find wide applications in biology. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Spectroscopic investigations on sorption of uranium onto suspended bentonite. Effects of pH, ionic strength and complexing anions

    Energy Technology Data Exchange (ETDEWEB)

    Verma, Parveen Kumar; Pathak, Priyanath; Mohapatra, Manoj; Mohapatra, Prasanta Kumar [Bhabha Atomic Research Centre, Mumbai (India). Radiochemistry Div.; Yadav, Ashok Kumar; Jha, Sambhunath; Bhattacharyya, Dibyendu [Bhabha Atomic Research Centre, Mumbai (India). Atomic and Molecular Physics Div.

    2015-06-01

    Batch sorption experiments were carried out under aerobic conditions to understand the sorption behavior of U(VI) onto bentonite clay under varying pH (2-8) and ionic strength (I = 0.01 - 1 M (NaClO{sub 4})) conditions. The influences of different complexing anions (1 x 10{sup -4} M) such as oxalic acid (ox), carbonate (CO{sub 3}{sup 2-}), citric acid (cit), and humic acid (HA, 10 mg/L) on the sorption behavior were also investigated. The sorption of U(VI) increased with increasing pH up to pH 6 beyond which a decrease was attributed to the formation of anionic carbonate species. Marginal influence of the change in the ionic strength of the medium on the sorption profile of uranium suggested inner-sphere complexation onto the bentonite surface. The presence of humic acid showed interesting sorption profile with varying pH. Initially, there was an enhancement in the sorption with increased pH followed by a plateau and finally a decrease thereafter due to the formation of aqueous U(VI)-humate complexes. Spectroscopic studies such as UV spectrophotometry, luminescence and extended X-ray absorption fine structure (EXAFS) measurements were also performed to understand the changes in aqueous speciation of U(VI) ion. The luminescence yields of different aqueous U(VI) species followed the order: U(VI){sub Hydroxy} > U(VI){sub HumicAcid} > U(VI){sub carbonate} > U(VI){sub citrate}. The lower luminescence yield of U(VI)carbonate complex can be attributed to the strong dynamic quenching by carbonate at room temperature. The U(VI) samples shows two distinct life-time suggesting the presence of the different luminescent U(VI) species. Similar trend was observed for U(VI)-bentonite suspension in presence/absence of the complexing ligands. There was luminescence quenching for the sorbed U(VI) due to surface complexation. These observations were further supported by spectrophotometric measurements. EXAFS spectra of U(VI) samples were recorded in luminescence mode at the U L{sub 3

  12. Effect of habitual arecanut chewing on resting whole mouth salivary flow rate and pH

    OpenAIRE

    Rooban T; Mishra G; Elizabeth J; Ranganathan K; Saraswathi T

    2006-01-01

    BACKGROUND: Resting whole mouth salivary flow rate (SFR) and pH play a significant role in pathogenesis of various oral diseases and conditions. AIM: To observe the effect of habitual use of arecanut and various arecanut containing products (AN) on SFR and pH. DESIGN: Cross sectional. SETTING: Outpatient Department of Dental College. PARTICIPANTS: AN chewers and non-chewers attending Dental college. MEASUREMENTS: SFR and pH. VARIABLES: Type, frequency, duration and exposure time of AN, Smokin...

  13. Secondary side water chemistry pH control strategy improvements

    Energy Technology Data Exchange (ETDEWEB)

    Roumiguiere, Fernando-Mario; Fandrich, Joerg; Ramminger, Ute; Hoffmann-Wankerl, Stephan; Drexler, Andreas [AREVA NP GmbH, Erlangen (Germany)

    2012-11-15

    When selecting a pH control strategy, plant design and operation characteristics have to be carefully considered. The strategy should be tailored to the plant-specific needs and requirements. Owing to the complexity of the interrelated variables, the best way is to perform a modeling with a suitable computer code. This work investigated the possibility of complementing the classic high pH all-volatile treatment (H-AVT) by addition of an organic amine at low concentrations complementarily to ammonia dosing to locally increase the pH in the water phase of the wet steam areas to counteract flow-assisted corrosion (FAC). Alternative conditioning scenarios were considered and calculated for comparative analysis using a computer code. The results obtained argue for the convenience of using ammonia as the main alkalizing agent whenever possible, avoiding multiple amine concepts and their associated drawbacks. (orig.)

  14. Dynamic regulation of gastric surface pH by luminal pH

    OpenAIRE

    Chu, Shaoyou; Tanaka, Shin; Kaunitz, Jonathan D.; Montrose, Marshall H.

    1999-01-01

    In vivo confocal imaging of the mucosal surface of rat stomach was used to measure pH noninvasively under the mucus gel layer while simultaneously imaging mucus gel thickness and tissue architecture. When tissue was superfused at pH 3, the 25 μm adjacent to the epithelial surface was relatively alkaline (pH 4.1 ± 0.1), and surface alkalinity was enhanced by topical dimethyl prostaglandin E2 (pH 4.8 ± 0.2). Luminal pH was changed from pH 3 to pH 5 to mimic the fasted-to-fed transition in intra...

  15. Digestion products of the PH20 hyaluronidase inhibit remyelination.

    Science.gov (United States)

    Preston, Marnie; Gong, Xi; Su, Weiping; Matsumoto, Steven G; Banine, Fatima; Winkler, Clayton; Foster, Scott; Xing, Rubing; Struve, Jaime; Dean, Justin; Baggenstoss, Bruce; Weigel, Paul H; Montine, Thomas J; Back, Stephen A; Sherman, Larry S

    2013-02-01

    Oligodendrocyte progenitor cells (OPCs) recruited to demyelinating lesions often fail to mature into oligodendrocytes (OLs) that remyelinate spared axons. The glycosaminoglycan hyaluronan (HA) accumulates in demyelinating lesions and has been implicated in the failure of OPC maturation and remyelination. We tested the hypothesis that OPCs in demyelinating lesions express a specific hyaluronidase, and that digestion products of this enzyme inhibit OPC maturation. Mouse OPCs grown in vitro were analyzed for hyaluronidase expression and activity. Gain of function studies were used to define the hyaluronidases that blocked OPC maturation. Mouse and human demyelinating lesions were assessed for hyaluronidase expression. Digestion products from different hyaluronidases and a hyaluronidase inhibitor were tested for their effects on OPC maturation and functional remyelination in vivo. OPCs demonstrated hyaluronidase activity in vitro and expressed multiple hyaluronidases, including HYAL1, HYAL2, and PH20. HA digestion by PH20 but not other hyaluronidases inhibited OPC maturation into OLs. In contrast, inhibiting HA synthesis did not influence OPC maturation. PH20 expression was elevated in OPCs and reactive astrocytes in both rodent and human demyelinating lesions. HA digestion products generated by the PH20 hyaluronidase but not another hyaluronidase inhibited remyelination following lysolecithin-induced demyelination. Inhibition of hyaluronidase activity lead to increased OPC maturation and promoted increased conduction velocities through lesions. We determined that PH20 is elevated in demyelinating lesions and that increased PH20 expression is sufficient to inhibit OPC maturation and remyelination. Pharmacological inhibition of PH20 may therefore be an effective way to promote remyelination in multiple sclerosis and related conditions. Copyright © 2012 American Neurological Association.

  16. Resilience and recovery of Dehalococcoides mccartyi following low pH exposure.

    Science.gov (United States)

    Yang, Yi; Cápiro, Natalie L; Yan, Jun; Marcet, Tyler F; Pennell, Kurt D; Löffler, Frank E

    2017-12-01

    Bioremediation treatment (e.g. biostimulation) can decrease groundwater pH with consequences for Dehalococcoides mccartyi (Dhc) reductive dechlorination activity. To explore the pH resilience of Dhc, the Dhc-containing consortium BDI was exposed to pH 5.5 for up to 40 days. Following 8- and 16-day exposure periods to pH 5.5, dechlorination activity and growth recovered when returned to pH 7.2; however, the ability of the culture to dechlorinate vinyl chloride (VC) to ethene was impaired (i.e. decreased rate of VC transformation). Dhc cells exposed to pH 5.5 for 40 days did not recover the ethene-producing phenotype upon transfer to pH 7.2 even after 200 days of incubation. When returned to pH 7.2 conditions after an 8-, a 16- and a 40-day low pH exposure, tceA and vcrA genes showed distinct fold increases, suggesting Dhc strain-specific responses to low pH exposure. Furthermore, a survey of Dhc biomarker genes in groundwater samples revealed the average abundances of Dhc 16S rRNA, tceA and vcrA genes in pH 4.5-6 groundwater were significantly lower (P-value pH 6-8.3 groundwater. Overall, the results of the laboratory study and the assessment of field data demonstrate that sustained Dhc activity should not be expected in low pH groundwater, and the duration of low pH exposure affects the ability of Dhc to recover activity at circumneutral pH. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  17. Histone deacetylase-mediated regulation of endolysosomal pH.

    Science.gov (United States)

    Prasad, Hari; Rao, Rajini

    2018-05-04

    The pH of the endolysosomal system is tightly regulated by a balance of proton pump and leak mechanisms that are critical for storage, recycling, turnover, and signaling functions in the cell. Dysregulation of endolysosomal pH has been linked to aging, amyloidogenesis, synaptic dysfunction, and various neurodegenerative disorders, including Alzheimer's disease. Therefore, understanding the mechanisms that regulate luminal pH may be key to identifying new targets for managing these disorders. Meta-analysis of yeast microarray databases revealed that nutrient-limiting conditions inhibited the histone deacetylase (HDAC) Rpd3 and thereby up-regulated transcription of the endosomal Na + /H + exchanger Nhx1, resulting in vacuolar alkalinization. Consistent with these findings, Rpd3 inhibition by the HDAC inhibitor and antifungal drug trichostatin A induced Nhx1 expression and vacuolar alkalinization. Bioinformatics analysis of Drosophila and mouse databases revealed that caloric control of the Nhx1 orthologs DmNHE3 and NHE6, respectively, is also mediated by HDACs. We show that NHE6 is a target of the transcription factor cAMP-response element-binding protein (CREB), a known regulator of cellular responses to low-nutrient conditions, providing a molecular mechanism for nutrient- and HDAC-dependent regulation of endosomal pH. Of note, pharmacological targeting of the CREB pathway to increase NHE6 expression helped regulate endosomal pH and correct defective clearance of amyloid Aβ in an apoE4 astrocyte model of Alzheimer's disease. These observations from yeast, fly, mouse, and cell culture models point to an evolutionarily conserved mechanism for HDAC-mediated regulation of endosomal NHE expression. Our insights offer new therapeutic strategies for modulation of endolysosomal pH in fungal infection and human disease. © 2018 Prasad and Rao.

  18. Effects of pH on embryo tolerance and adult behavior in the tiger salamander, Ambystoma tigrinum tigrinum

    Energy Technology Data Exchange (ETDEWEB)

    Whiteman, H H; Howard, R D; Whitten, K A [Purdue Univ., Lafayette, IN (United States). Dept. of Biological Sciences

    1995-08-01

    Adult discrimination ability and embryo performance was examined under different pH conditions in the eastern tiger salamander. Individuals from three populations were collected in habitats that differed naturally in pH. Two pH treatments were used to determine adult pH discrimination ability, and eight pH treatments to evaluate embryo performance. Results suggested that the pH of the source-population habitat could influence breeding-habitat discrimination by adults. Decreasing pH produced similar patterns of lethal and sublethal effects on embryos from the three populations, with reduced performance at low pH. The pH at which 50% mortality occurs was estimated at 4.2, suggesting that tiger salamanders were relatively acid tolerant. The study suggested that adult behavior patterns could influence the success of population reintroductions to previously acidified areas. 78 refs., 2 tabs., 4 figs.

  19. Eesti film võistleb Karlovy Varys

    Index Scriptorium Estoniae

    2008-01-01

    8. juulil esilinastub Karlovy Vary filmifestivalil Rene Vilbre noortefilm "Mina olin siin", mille aluseks on Sass Henno romaan "Mina olin siin. Esimene arest", stsenaariumi kirjutas Ilmar Raag. Film võistleb võistlusprogrammis "East of the West"

  20. Matching Value Propositions with Varied Customer Needs

    DEFF Research Database (Denmark)

    Heikka, Eija-Liisa; Frandsen, Thomas; Hsuan, Juliana

    2018-01-01

    Organizations seek to manage varied customer segments using varied value propositions. The ability of a knowledge-intensive business service (KIBS) provider to formulate value propositions into attractive offerings to varied customers becomes a competitive advantage. In this specific business based...... on often highly abstract service offerings, this requires the provider to have a clear overview of its knowledge and resources and how these can be configured to obtain the desired customization of services. Hence, the purpose of this paper is to investigate how a KIBS provider can match value propositions...... with varied customer needs utilizing service modularity. To accomplish this purpose, a qualitative multiple case study is organized around 5 projects allowing within-case and cross-case comparisons. Our findings describe how through the configuration of knowledge and resources a sustainable competitive...

  1. Compilation of Instantaneous Source Functions for Varying ...

    African Journals Online (AJOL)

    Compilation of Instantaneous Source Functions for Varying Architecture of a Layered Reservoir with Mixed Boundaries and Horizontal Well Completion Part III: B-Shaped Architecture with Vertical Well in the Upper Layer.

  2. Compilation of Instantaneous Source Functions for Varying ...

    African Journals Online (AJOL)

    Compilation of Instantaneous Source Functions for Varying Architecture of a Layered Reservoir with Mixed Boundaries and Horizontal Well Completion Part IV: Normal and Inverted Letter 'h' and 'H' Architecture.

  3. pH variations during diafiltration due to buffer nonidealities.

    Science.gov (United States)

    Baek, Youngbin; Yang, Deyu; Singh, Nripen; Arunkumar, Abhiram; Ghose, Sanchayita; Li, Zheng Jian; Zydney, Andrew L

    2017-11-01

    Diafiltration is used for final formulation of essentially all biotherapeutics. Several studies have demonstrated that buffer/excipient concentrations in the final diafiltered product can be different than that in the diafiltration buffer due to interactions between buffer species and the protein product. However, recent work in our lab has shown variations in solution pH that are largely independent of the protein concentration during the first few diavolumes. Our hypothesis is that these pH variations are due to nonidealities in the acid-base equilibrium coefficient. A model was developed for the diafiltration process accounting for the ionic strength dependence of the pK a . Experimental results obtained using phosphate and histidine buffers were in excellent agreement with model predictions. A decrease in ionic strength leads to an increase in the pK a for the phosphate buffer, causing a shift in the solution pH, even under conditions where the initial feed and the diafiltration buffer are at the same pH. This effect could be eliminated by matching the ionic strength of the feed and diafiltration buffer. The experimental data and model provide new insights into the factors controlling the pH profile during diafiltration processes. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:1555-1560, 2017. © 2017 American Institute of Chemical Engineers.

  4. Brane world cosmologies with varying speed of light

    International Nuclear Information System (INIS)

    Youm, Donam

    2001-02-01

    We study cosmologies in the Randall-Sundrum models, incorporating the possibility of time-varying speed of light and Newton's constant. The cosmologies with varying speed of light (VSL) were proposed by Moffat and by Albrecht and Magueijo as an alternative to inflation for solving the cosmological problems. We consider the case in which the speed of light varies with time after the radion or the scale of the extra dimension has been stabilized. We elaborate on the conditions under which the flatness problem and the cosmological constant problem can be resolved. Particularly, the VSL cosmologies may provide a possible mechanism for bringing the quantum corrections to the fine-tuned brane tensions after the SUSY breaking under control. (author)

  5. Determination of pH by flow-injection analysis and by fiber-optrode analysis

    International Nuclear Information System (INIS)

    Pia, S.H.; Waltman, D.P.; Hillman, D.C.

    1988-07-01

    Two new procedures for measuring pH were developed. The first measures pH colorimetrically using a proprietary indicator-dye mixture in a flow injection analysis (FIA) procedure. The second measures pH using a fiber-optic chemical sensor (FOCS) specifically developed for pH determinations. The FOCS method measures pH by monitoring the fluorescence of a fluorescein derivative bonded to the distal end of a fiber-optic cable called an optrade. The FIA method currently has a precision and accuracy of about + or - 0.2 pH units and can measure 100 samples/hour. The FOCS method has a precision of + or - 0.05-0.20 pH units and an accuracy of + or - 0.1 to 0.6 pH units. About 10 to 60 samples can be analyzed. The characteristics of the FOCS Method will vary significantly with individual optrodes. The experimental results indicate that either flow-injection analysis or fiber optic chemical sensor analysis could form the basis for an alternative to electrometric measurement of pH in certain circumstances

  6. Recent Developments in R.F. Magnetron Sputtered Thin Films for pH Sensing Applications—An Overview

    OpenAIRE

    D. K. Maurya; A. Sardarinejad; K. Alameh

    2014-01-01

    pH sensors are widely used in chemical and biological applications. Metal oxides-based pH sensors have many attractive features including insolubility, stability, mechanical strength, electrocatalyst and manufacturing technology. Various metal oxide thin films prepared by radio frequency (R.F.) magnetron sputtering have attractive features, including high pH sensitivity, fast response, high resolution, good stability and reversibility as well as potential for measuring pH under conditions th...

  7. Determination of the intracellular pH of intact erythrocytes by 1H NMR spectroscopy

    International Nuclear Information System (INIS)

    Rabenstein, D.L.; Isab, A.A.

    1982-01-01

    A method is described for determining the intracellular pH of intact erythrocytes by 1 H NMR. The determination is based on the pH dependence of the chemical shifts of resonances for carbon-bounded protons of an indicator molecule (imidazole) in intact cells. The imidazole is introduced into the erythrocytes by incubation in an isotonic saline solution of the indicator. The pH dependence of the chemical shifts of the imidazole resonances is calibrated from 1 H NMR spectra of the imidazole-containing red cell lysates whose pH is varied by the addition of acid or base and measured directly with a pH electrode. To reduce in intensity or eliminate the much more intense envelope of resonances from the hemoglobin, the 1 H NMR measurements are made by either the spin-echo Fourier transform technique or by the transfer-or-saturation by cross-relaxation method

  8. Polymorphisms in Renal Ammonia Metabolism Genes Correlate With 24-Hour Urine pH

    Directory of Open Access Journals (Sweden)

    Benjamin K. Canales

    2017-11-01

    Discussion: Overall, these findings suggest that variants in common genes involved in ammonia metabolism may substantively contribute to basal urine pH regulation. These variations might influence the likelihood of developing disease conditions associated with altered urine pH, such as uric acid or calcium phosphate kidney stones.

  9. Intracellular pH is a tightly controlled signal in yeast

    NARCIS (Netherlands)

    Orij, R.; Brul, S.; Smits, G.J.

    2011-01-01

    Background: Nearly all processes in living cells are pH dependent, which is why intracellular pH (pHi) is a tightly regulated physiological parameter in all cellular systems. However, in microbes such as yeast, pHi responds to extracellular conditions such as the availability of nutrients. This

  10. Development of a microprocessor-controlled coulometric system for stable ph control

    NARCIS (Netherlands)

    Bergveld, Piet; van der Schoot, B.H.

    1983-01-01

    The coulometric pH control system utilizes a programmable coulostat for controlling the pH of a certain volume of unbuffered solution. Based on theoretical considerations, conditions are established which guarantee stable operation with maximum suppression of disturbances from the dissolution of

  11. How Neighborhood Effects Vary: Childbearing and Fathering among Latino and African American Adolescents

    Directory of Open Access Journals (Sweden)

    Jessica L. Lucero

    2018-01-01

    Full Text Available This study examines what neighborhood conditions experienced at age 15 and after are associated with teen childbearing and fathering among Latino and African American youth and whether these neighborhood effects vary by gender and/or ethnicity. Administrative and survey data from a natural experiment are used for a sample of 517 Latino and African American youth whose families were quasi-randomly assigned to public housing operated by the Denver (CO Housing Authority (DHA. Characteristics of the neighborhood initially assigned by DHA to wait list applicants are utilized as identifying instruments for the neighborhood contexts experienced during adolescence. Cox Proportional Hazards (PH models reveal that neighborhoods having higher percentages of foreign-born residents but lower levels of social capital robustly predict reduced odds of teen parenting though the magnitude of these effects was contingent on gender and ethnicity. Specifically, the presence of foreign-born neighbors on the risk of teen parenting produced a stronger dampening effect for African American youth when compared to Latino youth. Additionally, the effects of social capital on teen parenting were stronger for males than females.

  12. [Characteristics of precipitation pH and conductivity at Mt. Huang].

    Science.gov (United States)

    Shi, Chun-e; Deng, Xue-liang; Wu, Bi-wen; Hong, Jie; Zhang, Su; Yang, Yuan-jian

    2013-05-01

    To understand the general characteristics of pH distribution and pollution in precipitation at Mt. Huang, statistical analyses were conducted for the routine measurements of pH and conductivity (K) at Mt. Huang during 2006-2011. The results showed that: (1) Over the period of study, the annual volume weighted mean (VWM) precipitation pH varied from 4.81 to 5.57, with precipitation acidity strengthening before 2009 and weakening thereafter. The precipitation acidity showed evident seasonal variations, with the VWM pH lowest in winter (4.78), and highest in summer (5.33). The occurrence frequency of acid rain was 46% , accounting for 45% of total rainfalls and with the most frequent pH falling into weak acid to neutral rain. (2) The annual VWM K varied from 16.91 to 27.84 microS x cm(-1), with no evident trend. As for ions pollution, the precipitation was relatively clean at Mt. Huang, with the most frequent K range being below 15 microS x cm(-1), followed by 15-25 microS x cm(-1). From February 2010 to December 2011, precipitation samples were collected on daily basis for ions analysis, as well as pH and K measurement in lab. Detailed comparisons were conducted between the two sets of pH and K, one set from field measurement and the other from lab measurement. The results indicated: (1) The lab measured pH (K) was highly correlated with the field pH (K); however, the lab pH tended to move towards neutral comparing with the corresponding field pH, and the shift range was closely correlated with the field pH and rainfall. The shift range of K from field to lab was highly correlated with the total ion concentration of precipitation. The field K showed evident negative correlation with the field pH with a correlation coefficient of -0.51. (2) When sampling with nylon-polyethylene bags, the statistics showed smaller bias between two sets of pH, with higher correlation coefficient between two sets of K. Furthermore, the lab K also showed evident negative correlation with

  13. pH distribution in human tumors

    International Nuclear Information System (INIS)

    Thistlethwaite, A.J.; Leeper, D.B.; Moylan, D.J.; Nerlinger, R.E.

    1984-01-01

    pH distribution in human tumors is being determined to evaluate this parameter as a prognostic indicator of hyperthermia response. pH is measured by a modified glass pH electrode (21g, model MI 408, Microelectrodes, Inc., Londonderry, NH) inserted through an 18g open-ended Angiocath. Eight tumors have been evaluated to date; and of those, 3 were also assayed after the first heat treatment coincident with determination of blood flow. Tumors were between 2-5 cm, of various histologies, and of primary, recurrent, or metastatic origin. 2-4 measurements were made per tumor. Pretreatment readings were between 6.4 and 7.2 pH units. As tumor blood flow increased after 1 hr heating (41.5 - 43 0 ) pH rose 0.1 - 0.3 units. Normal rat muscle yields pH readings of 7.35 - 7.45. Although there was considerable heterogeneity of pH within tumors, accuracy and drift were not a problem. 5-15 min were required for pH stabilization after catheter insertion and <5 min after electrode insertion. A saline wheal was used for anesthesia to preclude modification of pH by anesthetics. Patient tolerance has not been a problems. This study suggests that human tumor tissue has a preponderance of areas more acidic than normal tissue. This may serve to sensitize tumor cells to hyperthermia and provide a prognostic indicator of tumor response

  14. Regulation of arsenic mobility on basaltic glass surfaces by speciation and pH.

    Science.gov (United States)

    Sigfusson, Bergur; Meharg, Andrew A; Gislason, Sigurdur R

    2008-12-01

    The importance of geothermal energy as a source for electricity generation and district heating has increased over recent decades. Arsenic can be a significant constituent of the geothermal fluids pumped to the surface during power generation. Dissolved As exists in different oxidation states, mainly as As(III) and As(V), and the charge of individual species varies with pH. Basaltic glass is one of the most important rock types in many high-temperature geothermal fields. Static batch and dynamic column experiments were combined to generate and validate sorption coefficients for As(III) and As(V) in contact with basaltic glass at pH 3-10. Validation was carried out by two empirical kinetic models and a surface complexation model (SCM). The SCM provided a better fit to the experimental column data than kinetic models at high pH values. However, in certain circumstances, an adequate estimation of As transport in the column could not be attained without incorporation of kinetic reactions. The varying mobility with pH was due to the combined effects of the variable charge of the basaltic glass with the pH point of zero charge at 6.8 and the individual As species as pH shifted, respectively. The mobility of As(III) decreased with increasing pH. The opposite was true for As(V), being nearly immobile at pH 3 to being highly mobile at pH 10. Incorporation of appropriate sorption constants, based on the measured pH and Eh of geothermal fluids, into regional groundwater-flow models should allow prediction of the As(III) and As(V) transport from geothermal systems to adjacent drinking water sources and ecosystems.

  15. Competitive immobilization of Pb in an aqueous ternary-metals system by soluble phosphates with varying pH.

    Science.gov (United States)

    Zhang, Zhuo; Ren, Jie; Wang, Mei; Song, Xinlai; Zhang, Chao; Chen, Jiayu; Li, Fasheng; Guo, Guanlin

    2016-09-01

    Chemical immobilization by phosphates has been widely and successfully applied to treat Pb in wastewater and contaminated soils. Pb in wastewaters and soils, however, always coexists with other heavy metals and their competitive reactions with phosphates have not been quantitatively and systematically studied. In this approach, immobilization of Pb, Zn, and Cd by mono-, di-, and tripotassium phosphate (KH2PO4, K2HPO4, and K3PO4) was observed in the single- and ternary-metals solutions. The immobilization rates of the three metals were determined by the residual concentration. The mineral composition and structure of the precipitates were characterized by powder X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM). The results indicated that competitive reaction occurred in Pb-Zn-Cd ternary system, with immobilization rates decrease of system. The reaction of Pb with three phosphates exhibited intense competitiveness and the phosphates had a stronger affinity for Pb when Cl(-) was added. Pb-phosphate minerals formed by KH2PO4 with the better crystalline characteristics and largest size were very stable with a low dissolution rate (system. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Effects of niacin supplementation and dietary concentrate proportion on body temperature, ruminal pH and milk performance of primiparous dairy cows.

    Science.gov (United States)

    Lohölter, Malte; Meyer, Ulrich; Rauls, Caroline; Rehage, Jürgen; Dänicke, Sven

    2013-06-01

    The objective of this study was to investigate the effects of niacin and dietary concentrate proportion on body temperature, ruminal pH and milk production of dairy cows. In a 2 × 2 factorial design, 20 primiparous Holstein cows (179 ± 12 days in milk) were assigned to four dietary treatments aimed to receive either 0 or 24 g niacin and 30% (low) or 60% (high) concentrate with the rest being a partial mixed ration (PMR) composed of 60% corn and 40% grass silage (on dry matter basis). Ambient temperature and relative humidity were determined and combined by the calculation of temperature humidity index. Respiration rates, rectal, skin and subcutaneous temperatures were measured. Milk production and composition were determined. Ruminal pH and temperature were recorded at a frequency of 5 min using wireless devices for continuous intra-ruminal measurement (boluses). pH values were corrected for pH sensor drift. The climatic conditions varied considerably but temporarily indicated mild heat stress. Niacin did not affect skin, rectal and subcutaneous temperatures but tended to increase respiration rates. High concentrate reduced skin temperatures at rump, thigh and neck by 0.1-0.3°C. Due to the technical disturbances, not all bolus data could be subjected to statistical evaluation. However, both niacin and high concentrate influenced mean ruminal pH. High concentrate increased the time spent with a pH below 5.6 and ruminal temperatures (0.2-0.3°C). Niacin and high concentrate enhanced milk, protein and lactose yield but reduced milk fat and protein content. Milk fat yield was slightly reduced by high concentrate but increased due to niacin supplementation. In conclusion, niacin did not affect body temperature but stimulated milk performance. High concentrate partially influenced body temperatures and had beneficial effects on milk production.

  17. In Vitro binding capacity of zeolite A to calcium, phosphorus and magnesium in rumen fluid as influenced by changes in pH

    DEFF Research Database (Denmark)

    Thilsing, Trine; Jørgensen, Rolf Jess; Poulsen, H.D.

    2006-01-01

    with and without zeolite, as well as varying the content of Ca and/or P. The pH was lowered by addition of HCl so as to mimic abomasal conditions, followed by subsequent HCO3- addition to mimic small intestinal pH. Rumen fluid samples were taken at strategic time points in the experiment. All samples were......An in vitro experiment was designed to mimic the transport of ingested zeolite A in the forestomachs and proximal part of the small intestine so as to evaluate the binding capacity of zeolite A to Ca, P and Mg as influenced by changes in pH. This was done by incubation of rumen fluid solutions...... centrifuged and the supernatant analysed for Ca, P and Mg as indicators of the amount of unbound mineral. The addition of zeolite to rumen fluid solutions reduced the amount of supernatant Ca and Mg at rumen pH, whereas the level of P was not reduced. After adding HCl, a large proportion of the zeolite...

  18. Effect of pH on the optical and structural properties of HfO{sub 2}:Ln{sup 3+}, synthesized by hydrothermal route

    Energy Technology Data Exchange (ETDEWEB)

    Montes, E., E-mail: emontesr@live.com.mx [Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada IPN, Legaría 694, 11500, D.F. (Mexico); Martínez-Merlín, I.; Guzmán-Olguín, J.C.; Guzmán-Mendoza, J. [Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada IPN, Legaría 694, 11500, D.F. (Mexico); Martín, I.R. [Depto. de Física Fundamental y Experimental, Electrónica y Sistemas, Univ. de La Laguna, Av. Astrofísico Francisco Sánchez s/n E-38206, La Laguna. Tenerife (Spain); García-Hipólito, M. [Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México, Circuito Exterior, Cd. Universitaria, 04510, D.F. (Mexico); Falcony, C. [Departamento de Física, CINVESTAV IPN, Apartado Postal 14-740, 07000, D.F. (Mexico)

    2016-07-15

    In this work, the influence of the chlorine ions in the optical and structural properties of hafnium oxide (HfO{sub 2}) doped with europium (Eu{sup 3+}) and terbium (Tb{sup 3+}) are reported. The synthesis was conducted by hydrothermal route at a temperature of 200 °C, with a reaction time of 80 min and a concentration of 3 mol% of both dopants, in relation to hafnium in solution. In order to study the influence of acidity on the kinetics of reaction, the pH of the precursor solution was varied in the range of pH=4 to pH=12. X-ray powder diffraction patterns showed that the materials crystallized better under alkaline conditions with pH=11, noting a better crystallinity in the material doped with Eu{sup 3+}showed a better crystallinity that Tb{sup 3+} ions. The characteristic rhombohedral microstructure of HfO{sub 2} in the monoclinic phase was observed in alkaline media. Photoluminescent spectra showed the characteristic peaks of the emissions for both Eu an Tb dopants, where the intensity of the luminescent emission increases by decreasing the concentration of chlorine ions. On the other hand, it was found that radiative life kinetics of the dopant is related to the kinetics of crystallization, and therefore, to the acidity of the precursor solution.

  19. Varying constants, black holes, and quantum gravity

    International Nuclear Information System (INIS)

    Carlip, S.

    2003-01-01

    Tentative observations and theoretical considerations have recently led to renewed interest in models of fundamental physics in which certain 'constants' vary in time. Assuming fixed black hole mass and the standard form of the Bekenstein-Hawking entropy, Davies, Davis and Lineweaver have argued that the laws of black hole thermodynamics disfavor models in which the fundamental electric charge e changes. I show that with these assumptions, similar considerations severely constrain 'varying speed of light' models, unless we are prepared to abandon cherished assumptions about quantum gravity. Relaxation of these assumptions permits sensible theories of quantum gravity with ''varying constants,'' but also eliminates the thermodynamic constraints, though the black hole mass spectrum may still provide some restrictions on the range of allowable models

  20. Revealing the Dimeric Crystal and Solution Structure of β-Lactoglobulin at pH 4 and Its pH and Salt Dependent Monomer–Dimer Equilibrium

    DEFF Research Database (Denmark)

    Khan, Sanaullah; Ipsen, Richard; Almdal, Kristoffer

    2018-01-01

    The dimeric structure of bovine β-lactoglobulin A (BLGA) at pH 4.0 was solved to 2.0 Å resolution. Fitting the BLGA pH 4.0 structure to SAXS data at low ionic strength (goodness of fit R-factor = 3.6%) verified the dimeric state in solution. Analysis of the monomer–dimer equilibrium at varying pH...... and ionic strength by SAXS and scattering modeling showed that BLGA is dimeric at pH 3.0 and 4.0, shifting toward a monomer at pH 2.2, 2.6, and 7.0 yielding monomer/dimer ratios of 80/20%, 50/50%, and 25/75%, respectively. BLGA remained a dimer at pH 3.0 and 4.0 in 50–150 mM NaCl, whereas the electrostatic...... shielding raised the dimer content at pH 2.2, 2.6, and 7.0, i.e., below and above the pI. Overall, the findings provide new insights into the molecular characteristics of BLGA relevant for dairy product formulations and for various biotechnological and pharmaceutical applications....

  1. Experimental and theoretical evaluation of nanodiamonds as pH triggered drug carriers

    KAUST Repository

    Yan, Jingjing

    2012-01-01

    Nanodiamond (ND) and its derivatives have been widely used for drug, protein and gene delivery. Herein, experimental and theoretical methods have been combined to investigate the effect of pH on the delivery of doxorubicin (DOX) from fluorescein labeled NDs (Fc-NDs). In the endosomal recycling process, the nanoparticle will pass from mildly acidic vesicle to pH ≈ 4.8; thus, it is important to investigate DOX release from NDs at different pH values. Fc-NDs released DOX dramatically under acidic conditions, while an increase in the DOX loading efficiency (up to 6.4 wt%) was observed under basic conditions. Further theoretical calculations suggest that H + weakens the electrostatistic interaction between ND surface carboxyl groups and DOX amino groups, and the interaction energies at pH < 7, pH 7 and pH > 7 are 10.4 kcal mol -1, 25.0 kcal mol -1 and 27.0 kcal mol -1 respectively. Cellular imaging experiments show that Fc-NDs are readily ingested by breast adenocarcinoma (BA) cells and cell viability tests prove that they can be utilized as a safe drug delivery vehicle. Furthermore, pH triggered DOX release has been tested in vitro (pH 7.4 and pH 4.83) in breast adenocarcinoma (BA) cells. © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2012.

  2. Effect of pH value of applied solution on radioiodine sorption by soils

    International Nuclear Information System (INIS)

    Szabova, T.

    1976-01-01

    Sorption of radioiodine by soils was followed under static conditions at different pH values of the initial solution in five soil types. Sorption of radioiodine by soils is affected by the amount of the organic mass and by the pH of solutions. With the same pH, soils containing a higher amount of the organic mass absorb more radioiodine. The highest sorption percentage of 131 I - for all pH values was found in meadow chernozem soil and the lowest in the rendzina and in carboniferous meadow soils. The highest sorption of 131 I - for degraded chernozem, meadow chernozem soils and brown soil was recorded at pH 5 and for carboniferous meadow soil and rendzina at pH 7. (author)

  3. Novel silica surface charge density mediated control of the optical properties of embedded optically active materials and its application for fiber optic pH sensing at elevated temperatures.

    Science.gov (United States)

    Wang, Congjun; Ohodnicki, Paul R; Su, Xin; Keller, Murphy; Brown, Thomas D; Baltrus, John P

    2015-02-14

    Silica and silica incorporated nanocomposite materials have been extensively studied for a wide range of applications. Here we demonstrate an intriguing optical effect of silica that, depending on the solution pH, amplifies or attenuates the optical absorption of a variety of embedded optically active materials with very distinct properties, such as plasmonic Au nanoparticles, non-plasmonic Pt nanoparticles, and the organic dye rhodamine B (not a pH indicator), coated on an optical fiber. Interestingly, the observed optical response to varying pH appears to follow the surface charge density of the silica matrix for all the three different optically active materials. To the best of our knowledge, this optical effect has not been previously reported and it appears universal in that it is likely that any optically active material can be incorporated into the silica matrix to respond to solution pH or surface charge density variations. A direct application of this effect is for optical pH sensing which has very attractive features that can enable minimally invasive, remote, real time and continuous distributed pH monitoring. Particularly, as demonstrated here, using highly stable metal nanoparticles embedded in an inorganic silica matrix can significantly improve the capability of pH sensing in extremely harsh environments which is of increasing importance for applications in unconventional oil and gas resource recovery, carbon sequestration, water quality monitoring, etc. Our approach opens a pathway towards possible future development of robust optical pH sensors for the most demanding environmental conditions. The newly discovered optical effect of silica also offers the potential for control of the optical properties of optically active materials for a range of other potential applications such as electrochromic devices.

  4. Fluoride release from fluoride varnishes under acidic conditions.

    Science.gov (United States)

    Lippert, F

    2014-01-01

    The aim was to investigate the in vitro fluoride release from fluoride varnishes under acidic conditions. Poly(methyl methacrylate) blocks (Perspex, n=3 per group) were painted with 80 ± 5 mg fluoride varnish (n=10) and placed into artificial saliva for 30 min. Then, blocks were placed into either 1% citric acid (pH 2.27) or 0.3% citric acid (pH 3.75) solutions (n=3 per solution and varnish) for 30 min with the solutions being replaced every 5 min. Saliva and acid solutions were analyzed for fluoride content. Data were analyzed using three-way ANOVA (varnish, solution, time). The three-way interaction was significant (p>0.0001). Fluoride release and release patterns varied considerably between varnishes. Fluoride release in saliva varied by a factor of more than 10 between varnishes. Some varnishes (CavityShield, Nupro, ProFluorid, Vanish) showed higher fluoride release in saliva than during the first 5 min of acid exposure, whereas other varnishes (Acclean, Enamel-Pro, MI Varnish, Vella) showed the opposite behavior. There was little difference between acidic solutions. Fluoride release from fluoride varnishes varies considerably and also depends on the dissolution medium. Bearing in mind the limitations of laboratory research, the consumption of acidic drinks after fluoride varnish application should be avoided to optimize the benefit/risk ratio.

  5. Some effects of pH on iodine volatility in containment

    International Nuclear Information System (INIS)

    Ashmore, C.B.; Gwyther, J.R.; Sims, H.E.

    1994-01-01

    The behaviour of iodine in containment in the event of an accident involving fission product release would be strongly dependent on pH. High pH leads to a lower rate of radiolytic oxidation and in alkaline conditions the thermally stable form is IO 3 - . Much of the work on effects of pH on radiolytic oxidation reported in the literature may be erroneous or misleading because of postirradiation reaction and in this report some new experiments are described which were designed to overcome these problems involving sparged irradiated solutions of CsI spiked with 131 I. The rate of radiolytic oxidation has been measured as a function of pH between pH 4.6 and pH 9 and iodide concentrations between 10 -4 and 10 -6 mol dm -3 . Also discussed in the paper are factors which can affect the pH of the sump water and the effects of high pH in sprays. It is concluded that high pH is beneficial and it is important not only to achieve high pH but to maintain it. (author). 10 refs., 1 tab., 6 figs

  6. Hyperpolarized Amino Acid Derivatives as Multivalent Magnetic Resonance pH Sensor Molecules.

    Science.gov (United States)

    Hundshammer, Christian; Düwel, Stephan; Ruseckas, David; Topping, Geoffrey; Dzien, Piotr; Müller, Christoph; Feuerecker, Benedikt; Hövener, Jan B; Haase, Axel; Schwaiger, Markus; Glaser, Steffen J; Schilling, Franz

    2018-02-15

    pH is a tightly regulated physiological parameter that is often altered in diseased states like cancer. The development of biosensors that can be used to non-invasively image pH with hyperpolarized (HP) magnetic resonance spectroscopic imaging has therefore recently gained tremendous interest. However, most of the known HP-sensors have only individually and not comprehensively been analyzed for their biocompatibility, their pH sensitivity under physiological conditions, and the effects of chemical derivatization on their logarithmic acid dissociation constant (p K a ). Proteinogenic amino acids are biocompatible, can be hyperpolarized and have at least two pH sensitive moieties. However, they do not exhibit a pH sensitivity in the physiologically relevant pH range. Here, we developed a systematic approach to tailor the p K a of molecules using modifications of carbon chain length and derivatization rendering these molecules interesting for pH biosensing. Notably, we identified several derivatives such as [1- 13 C]serine amide and [1- 13 C]-2,3-diaminopropionic acid as novel pH sensors. They bear several spin-1/2 nuclei ( 13 C, 15 N, 31 P) with high sensitivity up to 4.8 ppm/pH and we show that 13 C spins can be hyperpolarized with dissolution dynamic polarization (DNP). Our findings elucidate the molecular mechanisms of chemical shift pH sensors that might help to design tailored probes for specific pH in vivo imaging applications.

  7. Influence of mixed electrolytes and pH on adsorption of bovine serum albumin in hydrophobic interaction chromatography.

    Science.gov (United States)

    Hackemann, Eva; Hasse, Hans

    2017-10-27

    Using salt mixtures instead of single salts can be beneficial for hydrophobic interaction chromatography (HIC). The effect of electrolytes on the adsorption of proteins, however, depends on the pH. Little is known on that dependence for mixed electrolytes. Therefore, the effect of the pH on protein adsorption from aqueous solutions containing mixed salts is systematically studied in the present work for a model system: the adsorption of bovine serum albumin (BSA) on the mildly hydrophobic resin Toyopearl PPG-600M. The pH is adjusted to 4.0, 4.7 or 7.0 using 25mM sodium phosphate or sodium citrate buffer. Binary and ternary salt mixtures of sodium chloride, ammonium chloride, sodium sulfate and ammonium sulfate as well as the pure salts are used at overall ionic strengths between 1500 and 4200mM. The temperature is always 25°C. The influence of the mixed electrolytes on the adsorption behavior of BSA changes completely with varying pH. Positive as well as negative cooperative effects of the mixed electrolytes are observed. The results are analyzed using a mathematical model which was recently introduced by our group. In that model the influence of the electrolytes is described by a Taylor series expansion in the individual ion molarities. After suitable parametrization using a subset of the data determined in the present work, the model successfully predicts the influence of mixed electrolytes on the protein adsorption. Furthermore, results for BSA from the present study are compared to literature data for lysozyme, which are available for the same adsorbent, temperature and salts. By calculating the ratio of the loading of the adsorbent for both proteins particularly favorable separation conditions can be selected. Hence, a model-based optimization of solvents for protein separation is possible. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Adsorption of Sr(II) on clay minerals: effects of salt concentration, loading and pH

    International Nuclear Information System (INIS)

    Rafferty, P.; Shiao, S.Y.; Binz, C.M.; Meyer, R.E.

    1981-01-01

    The adsorption of Sr(II) on a number of clay minerals has been investigated by means of a batch technique in solutions of sodium salts. Generally the results can be approximated by ideal ion exchange equations. Distribution coefficients at trace loading follow the linear relation log D = s log [Na(I)sub(aq)] + b where b is a constant and s had values of from about - 1.5 to - 2.0, which are fairly close to the ideal valve of - 2. Adsorption isotherms at constant pH and salt concentration are linear in the low loading region. Distribution coefficients for montmorillonite are almost independent of pH in the intermediate pH region 5 to 7 but for illite and kaolinite, increases in the distribution coefficient with pH are observed. Comparison of these results with literature values, insofar as it is possible, shows that distribution coefficients are usually within a factor of two or three for the same mineral with similar capacities under the same conditions even if techniques of preparation and measurement are different, but values may vary considerably more if the capacities of the different mineral samples are greatly different. Values of the distribution coefficient at very high salt concentration are very low, considerably less than unity at 4 M NaCl. Thus migration rates of Sr(II), relative to water flow, through geologic formations whose adsorption behavior is dominated by these clay minerals are likely to be high at high salt concentrations. (author)

  9. Resilience to temperature and pH changes in a future climate change scenario in six strains of the polar diatom Fragilariopsis cylindrus

    Science.gov (United States)

    Pančić, M.; Hansen, P. J.; Tammilehto, A.; Lundholm, N.

    2015-07-01

    The effects of ocean acidification and increased temperature on physiology of six strains of the polar diatom Fragilariopsis cylindrus from Greenland were investigated. Experiments were performed under manipulated pH levels (8.0, 7.7, 7.4, and 7.1) and different temperatures (1, 5, and 8 °C) to simulate changes from present to plausible future levels. Each of the 12 scenarios was run for 7 days, and a significant interaction between temperature and pH on growth was detected. By combining increased temperature and acidification, the two factors counterbalanced each other, and therefore no effect on the growth rates was found. However, the growth rates increased with elevated temperatures by ~ 20-50 % depending on the strain. In addition, a general negative effect of increasing acidification on growth was observed. At pH 7.7 and 7.4, the growth response varied considerably among strains. However, a more uniform response was detected at pH 7.1 with most of the strains exhibiting reduced growth rates by 20-37 % compared to pH 8.0. It should be emphasized that a significant interaction between temperature and pH was found, meaning that the combination of the two parameters affected growth differently than when considering one at a time. Based on these results, we anticipate that the polar diatom F. cylindrus will be unaffected by changes in temperature and pH within the range expected by the end of the century. In each simulated scenario, the variation in growth rates among the strains was larger than the variation observed due to the whole range of changes in either pH or temperature. Climate change may therefore not affect the species as such, but may lead to changes in the population structure of the species, with the strains exhibiting high phenotypic plasticity, in terms of temperature and pH tolerance towards future conditions, dominating the population.

  10. Coaching af ph.d.-studerende

    DEFF Research Database (Denmark)

    Godskesen, Mirjam Irene

    Rapporten danner grundlag for at etablere et koncept for ph.d.-coaching. Erfaringerne fra et 2-årigt projekt om ph.d.-coaching i SCKK regi beskrives. De centrale temaer er tilrettelæggelse af den individuelle coaching, typiske temaer i coachingen og arbejdsdeling mellem coach og vejleder. Der er...

  11. Ph og børnenes rum

    DEFF Research Database (Denmark)

    de Coninck-Smith, Ning

    2008-01-01

    Arkiteten og kulturkritikeren PH tegnede to bygninger til børn, nemlig fabriksbørnehaven ved Dehns Vaskeri fra 1948 og det ombyggede børnehjem Mindet fra 1954. Bidraget diskuterer PH's særlige greb om arkitektur til børn og placerer det ind i samtidens diskussion om børn, deres udvikling og behov....

  12. PER PhDs & Bachelor's Degrees

    Science.gov (United States)

    White, Susan C.

    2017-01-01

    Recently, the editor remarked to me that physics departments that offered a PhD with a specialization in Physics Education Research (PER) seemed to graduate more bachelor's degree recipients than those physics PhD departments that did not have the specialization. I was not convinced. That led to quite a bit of discussion between us. He compiled a…

  13. Urbanism PhD Research 2008 - 2010

    NARCIS (Netherlands)

    Smit, M.; Van der Hoeven, F.D.; Brand, N.; Van der Burg, L.; Çal??kan, O.; Tan, E.R.; Wang, C.Y.; Zhou, J.

    2009-01-01

    To ensure the quality of the Ph.D. research the Department introduced a special procedure for periodic evaluation: after a period of nine months the potential Ph.D. candidates are asked to present their research design, theoretical framework and methodological approach to the members of the

  14. (ajst) the influence of ph and adsorbent

    African Journals Online (AJOL)

    goethite sorbed a little more metal ion than the natural goethite. This was attributed ... was greatly governed by pH with nearly 100% adsorption of Pb occurring at initial pH of 5. Generally, Pb was ... extensively study and applied for the removal of heavy .... Goethite has variable surface charge characteristics, which gave it a ...

  15. On Calibration of pH Meters

    Directory of Open Access Journals (Sweden)

    Da-Ming Zhu

    2005-04-01

    Full Text Available The calibration of pH meters including the pH glass electrode, ISE electrodes,buffers, and the general background for calibration are reviewed. Understanding of basicconcepts of pH, pOH, and electrode mechanism is emphasized. New concepts of pH, pOH,as well as critical examination of activity, and activity coefficients are given. Theemergence of new solid state pH electrodes and replacement of the salt bridge with aconducting wire have opened up a new horizon for pH measurements. A pH buffer solutionwith a conducting wire may be used as a stable reference electrode. The misleadingunlimited linear Nernstian slope should be discarded. Calibration curves with 3 nonlinearportions for the entire 0—14 pH range due to the isoelectric point change effect areexplained. The potential measurement with stirring or unstirring and effects by double layer(DL and triple layer (TL will be discussed.

  16. "Mina olin siin" esilinastub Karlovy Varys

    Index Scriptorium Estoniae

    2008-01-01

    Karlovy Vary filmifestivalil esilinastub Rene Vilbre noortefilm "Mina olin siin", mille aluseks on Sass Henno romaan "Mina olin siin. Esimene arest", stsenaariumi kirjutas Ilmar Raag. Film võistleb võistlusprogrammis "East of the West". Esitlema sõidavad R. Vilbre, R. Sildos, R. Kaljujärv, T. Tuisk

  17. Tracking time-varying coefficient-functions

    DEFF Research Database (Denmark)

    Nielsen, Henrik Aalborg; Nielsen, Torben Skov; Joensen, Alfred K.

    2000-01-01

    is a combination of recursive least squares with exponential forgetting and local polynomial regression. It is argued, that it is appropriate to let the forgetting factor vary with the value of the external signal which is the argument of the coefficient functions. Some of the key properties of the modified method...... are studied by simulation...

  18. Filmihullu eluvesi voolab Karlovy Varys / Margit Tõnson

    Index Scriptorium Estoniae

    Tõnson, Margit, 1978-

    2010-01-01

    Karlovy Vary rahvusvahelisest filmifestivalist. Filmidest "Mr. Nobody" (rež. Jaco Van Dormaeli), "Kasside ema Teresa" (rež. Pawel Sala) ja "The Arbor" (rež. Clio Barnardi). Nimekiri võitnud töödest ja viimastel aastatel festivalil näidatud Eesti mängufilmidest

  19. Õunpuu Karlovy Varys edukas

    Index Scriptorium Estoniae

    2010-01-01

    45. Karlovy Vary filmifestivali võistlusprogrammis "East of the West" märgiti ära Veiko Õunpuu film "Püha Tõnu kiusamine". Peaauhind läks rumeenlase Cristi Puiu filmile "Aurora". Grand prix´sai Augustĺ Vila film "La mosquitera". Teisi preemiasaajaid

  20. The effects of pH and concentration on heavy metal speciation and mobility, and its relation to heavy metal hyperaccumulation and distribution in selected native Australian flora

    International Nuclear Information System (INIS)

    Menon, D.D.; McPhail, D.C.; Hallam, N.

    2000-01-01

    Full text: The purpose of this research is to establish a clearer understanding of the relations that exist between heavy metal activity, speciation, bioavailability and their uptake and spatial distribution into plants. A combination of experimental modeling and pot trials using toxic heavy metals (cadmium, lead, mercury, copper, chromium and zinc) will be carried out. In the experiments, selected native Australian flora (Eucalyptus, Acacia, Atriplex) adapted to adverse environmental conditions will be used. Varying external factors such as pH, and metal concentration altered the composition of heavy metal speciation in the soil solution. Mathematical and geochemical (PHREEQC) models were used to vary these factors and emulate the conditions under which experimentation will be taking place. These variations help determine the possible heavy metal speciation that would occur in both soil and hydroponic based experiments under given conditions. The rhizosphere, soil solution and the plant material will be analysed by Inductively Coupled Plasma Mass Spectroscopy (ICPMS). Proton Ion X-ray Emission (PIXE) and Secondary Ion Mass spectrometry will help ascertain the distribution, concentration of heavy metal taken up into plant tissues. Information derived from these data will be used to determine and understand how varying such environmental conditions and hence heavy metal speciation affect their bioavailability in the medium, and how their acceptance, accumulation and storage within the selected flora. Preliminary experimentation showed that, for lead and cadmium, the variation in soil solution pH affected the quantity of heavy metal accumulated into selected native Australian flora. ICP-MS analysis of plants subjected to a known soil solution spiked with 200 μmol of lead and cadmium showed that the quantities of lead and cadmium accumulated into plant sections (roots, stems and leaves) varied in the selected woody species. A. heteroclita, A. saligna, and A

  1. Determination Of Ph Including Hemoglobin Correction

    Science.gov (United States)

    Maynard, John D.; Hendee, Shonn P.; Rohrscheib, Mark R.; Nunez, David; Alam, M. Kathleen; Franke, James E.; Kemeny, Gabor J.

    2005-09-13

    Methods and apparatuses of determining the pH of a sample. A method can comprise determining an infrared spectrum of the sample, and determining the hemoglobin concentration of the sample. The hemoglobin concentration and the infrared spectrum can then be used to determine the pH of the sample. In some embodiments, the hemoglobin concentration can be used to select an model relating infrared spectra to pH that is applicable at the determined hemoglobin concentration. In other embodiments, a model relating hemoglobin concentration and infrared spectra to pH can be used. An apparatus according to the present invention can comprise an illumination system, adapted to supply radiation to a sample; a collection system, adapted to collect radiation expressed from the sample responsive to the incident radiation; and an analysis system, adapted to relate information about the incident radiation, the expressed radiation, and the hemoglobin concentration of the sample to pH.

  2. Endoscopic sensing of alveolar pH.

    Science.gov (United States)

    Choudhury, D; Tanner, M G; McAughtrie, S; Yu, F; Mills, B; Choudhary, T R; Seth, S; Craven, T H; Stone, J M; Mati, I K; Campbell, C J; Bradley, M; Williams, C K I; Dhaliwal, K; Birks, T A; Thomson, R R

    2017-01-01

    Previously unobtainable measurements of alveolar pH were obtained using an endoscope-deployable optrode. The pH sensing was achieved using functionalized gold nanoshell sensors and surface enhanced Raman spectroscopy (SERS). The optrode consisted of an asymmetric dual-core optical fiber designed for spatially separating the optical pump delivery and signal collection, in order to circumvent the unwanted Raman signal generated within the fiber. Using this approach, we demonstrate a ~100-fold increase in SERS signal-to-fiber background ratio, and demonstrate multiple site pH sensing with a measurement accuracy of ± 0.07 pH units in the respiratory acini of an ex vivo ovine lung model. We also demonstrate that alveolar pH changes in response to ventilation.

  3. Development of Hybrid pH sensor for long-term seawater pH monitoring.

    Science.gov (United States)

    Nakano, Y.; Egashira, T.; Miwa, T.; Kimoto, H.

    2016-02-01

    We have been developing the in situ pH sensor (Hybrid pH sensor: HpHS) for the long-term seawater pH monitoring. We are planning to provide the HpHS for researchers and environmental consultants for observation of the CCS (Carbon dioxide Capture and Storage) monitoring system, the coastal environment monitoring system (e.g. Blue Carbon) and ocean acidification. The HpHS has two types of pH sensors (i.e. potentiometric pH sensor and spectrophotometric pH sensor). The spectrophotometric pH sensor can measure pH correctly and stably, however it needs large power consumption and a lot of reagents in a long period of observation. The pH sensor used m-cresol purple (mCP) as an indicator of pH (Clayton and Byrne, 1993 and Liu et al., 2011). We can choose both coefficients before deployment. On the other hand, although the potentiometric pH sensor is low power consumption and high-speed response (within 10 seconds), drifts in the pH of the potentiometric measurements may possibly occur for a long-term observation. The HpHS can measure in situ pH correctly and stably combining advantage of both pH sensors. The HpHS consists of an aluminum pressure housing with optical cell (main unit) and an aluminum silicon-oil filled, pressure-compensated vessel containing pumps and valves (diaphragm pump and valve unit) and pressure-compensated reagents bags (pH indicator, pure water and Tris buffer or certified reference material: CRM) with an ability to resist water pressure to 3000m depth. The main unit holds system control boards, pump drivers, data storage (micro SD card), LED right source, photodiode, optical cell and pressure proof windows. The HpHS also has an aluminum pressure housing that holds a rechargeable lithium-ion battery or a lithium battery for the power supply (DC 24 V). The HpHS is correcting the value of the potentiometric pH sensor (measuring frequently) by the value of the spectrophotometric pH sensor (measuring less frequently). It is possible to calibrate in

  4. Redox stability of neptunium(V) in the presence of humic substances of varying functionality

    Energy Technology Data Exchange (ETDEWEB)

    Schmeide, K.; Geipel, G.; Bernhard, G. [Forschungszentrum Rossendorf e.V., Institute of Radiochemistry, P.O. Box 510 119, D-01314 Dresden (Germany)

    2005-07-01

    Full text of publication follows: Naturally occurring aquatic humic substances (humic and fulvic acids) are known to effect the speciation and thus, the migration behavior of actinide contaminants in environmental systems due to their complexing and redox properties and their ability to form colloids. Therefore, to understand and predict the mobility of actinides in natural aquifer systems, amongst others, information on their redox stability in the presence of humic substances is necessary. In the present work, the time dependence of the reduction of Np(V) to Np(IV) by humic substances of varying functionality has been studied under anaerobic conditions between pH 3.5 and pH 9. Synthetic humic acids with pronounced redox functionality (type Cat-Gly and Hyd-Glu) [1] were studied in comparison to natural humic substances (Aldrich humic acid, Kranichsee fulvic acid). For Np speciation in solution liquid-liquid extraction, laser-induced photoacoustic spectroscopy (LIPAS), NIR absorption spectroscopy, and ultrafiltration were applied. In comparison to the natural humic substances, the synthetic humic acids lead to a much stronger reduction of Np(V) to Np(IV) [2]. The Np(IV) formed in the course of the experiments is stabilized as Np(IV) humate. The tetravalent oxidation state of Np remained constant for several months. The redox capacities of the synthetic humic acids, which are significantly higher than those of the natural humic substances, can be attributed to their higher phenolic/acidic OH group contents compared to natural humic substances. The dominating role of phenolic/acidic OH groups for the reduction of Np(V) by humic substances could be verified applying a synthetic humic acid with blocked phenolic/acidic OH groups (type Hyd-Glu-PB). Furthermore, the influence of NO{sub 3}{sup -} on the Np(V) reduction by humic substances was studied. The results have shown that by application of the synthetic humic acids with distinct redox functionalities actinides can

  5. Interactions between iron, phenolic compounds, emulsifiers, and pH in omega-3-enriched oil-in-water emulsions

    DEFF Research Database (Denmark)

    Sørensen, Ann-Dorit Moltke; Haahr, Anne-Mette; Becker, E.M.

    2008-01-01

    The behavior of antioxidants in emulsions is influenced by several factors such as pH and emulsifier type. This study aimed to evaluate the interaction between selected food emulsifiers, phenolic compounds, iron, and pH and their effect on the oxidative stability of n-3 polyunsaturated lipids...... products. When iron was present, the pH was crucial for the formation of lipid oxidation products. At pH 3 some phenolic compounds, especially caffeic acid, reduced Fe3+ to Fe2+, and Fe2+ increased lipid oxidation at this pH compared to pH 6. Among the evaluated phenols, caffeic acid had the most...... significant effects, as caffeic acid was found to be prooxidative irrespective of pH, emulsifier type, and presence of iron, although the degrees of lipid oxidation were different at the different experimental conditions. The other evaluated phenols were prooxidative at pH 3 in Citrem-stabilized emulsions...

  6. Impact of desiccation and heat exposure stress on Salmonella tolerance to acidic conditions.

    Science.gov (United States)

    Richardson, Kurt E; Cox, Nelson A; Cosby, Douglas E; Berrang, Mark E

    2018-02-01

    In a recent study, the pH of commonly used Salmonella pre-enrichment media became acidic (pH 4.0 to 5.0) when feed or feed ingredients were incubated for 24 h. Acidic conditions have been reported to injure or kill Salmonella. In this study, cultures of four known feed isolates (S. montevideo, S. senftenberg, S. tennessee, and S. schwarzengrund) and four important processing plant isolates (S. typhimurium, S. enteritidis, S. infantis, and S. heidelberg) were grown on meat and bone meal and later subjected to desiccation and heat exposure to stress the microorganism. The impact of stress on the isolates ability to survive in acidic conditions ranging from pH 4.0 to 7.0 was compared to the non-stressed isolate. Cell injury was determined on xylose lysine tergitol 4 (XLT4) and cell death determined on nutrient agar (NA). When measured by cell death in non-stressed Salmonella, S. typhimurium was the most acid tolerant and S. heidelberg was the most acid sensitive whereas in stressed Salmonella, S. senftenberg was the most acid tolerant and S. tennessee was the most acid sensitive. The pH required to cause cell injury varied among isolates. With some isolates, the pH required for 50% cell death and 50% cell injury was similar. In other isolates, cell injury occurred at a more neutral pH. These findings suggest that the pH of pre-enrichment media may influence the recovery and bias the serotype of Salmonella recovered from feed during pre-enrichment.

  7. Modeling pH variation in reverse osmosis.

    Science.gov (United States)

    Nir, Oded; Bishop, Noga Fridman; Lahav, Ori; Freger, Viatcheslav

    2015-12-15

    The transport of hydronium and hydroxide ions through reverse osmosis membranes constitutes a unique case of ionic species characterized by uncommonly high permeabilities. Combined with electromigration, this leads to complex behavior of permeate pH, e.g., negative rejection, as often observed for monovalent ions in nanofiltration of salt mixtures. In this work we employed a rigorous phenomenological approach combined with chemical equilibrium to describe the trans-membrane transport of hydronium and