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Sample records for calcium oxide sorbent

  1. Mercury Control with Calcium-Based Sorbents and Oxidizing Agents

    Energy Technology Data Exchange (ETDEWEB)

    Thomas K. Gale

    2005-07-01

    This Final Report contains the test descriptions, results, analysis, correlations, theoretical descriptions, and model derivations produced from many different investigations performed on a project funded by the U.S. Department of Energy, to investigate calcium-based sorbents and injection of oxidizing agents for the removal of mercury. Among the technologies were (a) calcium-based sorbents in general, (b) oxidant-additive sorbents developed originally at the EPA, and (c) optimized calcium/carbon synergism for mercury-removal enhancement. In addition, (d) sodium-tetrasulfide injection was found to effectively capture both forms of mercury across baghouses and ESPs, and has since been demonstrated at a slipstream treating PRB coal. It has been shown that sodium-tetrasulfide had little impact on the foam index of PRB flyash, which may indicate that sodium-tetrasulfide injection could be used at power plants without affecting flyash sales. Another technology, (e) coal blending, was shown to be an effective means of increasing mercury removal, by optimizing the concentration of calcium and carbon in the flyash. In addition to the investigation and validation of multiple mercury-control technologies (a through e above), important fundamental mechanism governing mercury kinetics in flue gas were elucidated. For example, it was shown, for the range of chlorine and unburned-carbon (UBC) concentrations in coal-fired utilities, that chlorine has much less effect on mercury oxidation and removal than UBC in the flyash. Unburned carbon enhances mercury oxidation in the flue gas by reacting with HCl to form chlorinated-carbon sites, which then react with elemental mercury to form mercuric chloride, which subsequently desorbs back into the flue gas. Calcium was found to enhance mercury removal by stabilizing the oxidized mercury formed on carbon surfaces. Finally, a model was developed to describe these mercury adsorption, desorption, oxidation, and removal mechanisms, including

  2. MERCURY CONTROL WITH CALCIUM-BASED SORBENTS AND OXIDIZING AGENTS

    Energy Technology Data Exchange (ETDEWEB)

    Thomas K. Gale

    2002-06-01

    The initial tasks of this DOE funded project to investigate mercury removal by calcium-based sorbents have been completed, and initial testing results have been obtained. Mercury monitoring capabilities have been obtained and validated. An approximately 1MW (3.4 Mbtu/hr) Combustion Research Facility at Southern Research Institute was used to perform pilot-scale investigations of mercury sorbents, under conditions representative of full-scale boilers. The initial results of ARCADIS G&M proprietary sorbents, showed ineffective removal of either elemental or oxidized mercury. Benchscale tests are currently underway to ascertain the importance of differences between benchscale and pilot-scale experiments. An investigation of mercury-capture temperature dependence using common sorbents has also begun. Ordinary hydrated lime removed 80 to 90% of the mercury from the flue gas, regardless of the temperature of injection. High temperature injection of hydrated lime simultaneously captured SO{sub 2} at high temperatures and Hg at low temperatures, without any deleterious effects on mercury speciation. Future work will explore alternative methods of oxidizing elemental mercury.

  3. SIMULTANEOUS CONTROL OF HGO, SO2, AND NOX BY NOVEL OXIDIZED CALCIUM-BASED SORBENTS

    Science.gov (United States)

    The paper gives results of an investigation of two classes of calcium (Ca)-based sorbents (hydrated limes and silicate compounds). (NOTE: Efforts to develop multipollutant control strategies have demonstrated that adding certain oxidants to different classes of Ca-based sorbents...

  4. SIMULTANEOUS CONTROL OF HG(0), SO2, AND NOX BY NOVEL OXIDIZED CALCIUM-BASED SORBENTS

    Science.gov (United States)

    The paper gives results of an investigation of two classes of calcium (Ca)-based sorbents (hydrated limes and silicate compounds). {NOTE: Efforts to develop multipollutant control strategies have demonstrated that adding certain oxidants to different classes of Ca-based sorbents ...

  5. Effect of Calcium Oxide Additive on the Performance of Iron Oxide Sorbent for High-Temperature Coal Gas Desulfurization

    Institute of Scientific and Technical Information of China (English)

    Huiling Fan; Kechang Xie; Ju Shangguan; Fang Shen; Chunhu Li

    2007-01-01

    The effect of calcium oxide additive in iron oxide sorbent for hot gas desulfurization was investigated by XRD and TPR techniques. XRD characterization showed that CaO was highly dispersed after the calcination of sorbents. Calcium sulfate formed in the desulfurization was decomposed and regenerated to CaO by reacting with CO before the next sulfidation process. Calcium participated in every sulfidation/regeneration cycle and contributed to the enhancement of sulfur capacity. The TPR results showed that the reduction temperature of the sorbent increased with the increase of the content of calcium. Calcium played a role of retarding reduction. Therefore, the addition of calcium oxide additive will benefit the utilization of iron oxide sorbent in strongly reducing atmospheres.

  6. High temperature CO2 capture using calcium oxide sorbent in a fixed-bed reactor.

    Science.gov (United States)

    Dou, Binlin; Song, Yongchen; Liu, Yingguang; Feng, Cong

    2010-11-15

    The gas-solid reaction and breakthrough curve of CO(2) capture using calcium oxide sorbent at high temperature in a fixed-bed reactor are of great importance, and being influenced by a number of factors makes the characterization and prediction of these a difficult problem. In this study, the operating parameters on reaction between solid sorbent and CO(2) gas at high temperature were investigated. The results of the breakthrough curves showed that calcium oxide sorbent in the fixed-bed reactor was capable of reducing the CO(2) level to near zero level with the steam of 10 vol%, and the sorbent in CaO mixed with MgO of 40 wt% had extremely low capacity for CO(2) capture at 550°C. Calcium oxide sorbent after reaction can be easily regenerated at 900°C by pure N(2) flow. The experimental data were analyzed by shrinking core model, and the results showed reaction rates of both fresh and regeneration sorbents with CO(2) were controlled by a combination of the surface chemical reaction and diffusion of product layer. PMID:20724072

  7. High temperature CO2 capture using calcium oxide sorbent in a fixed-bed reactor

    International Nuclear Information System (INIS)

    The gas-solid reaction and breakthrough curve of CO2 capture using calcium oxide sorbent at high temperature in a fixed-bed reactor are of great importance, and being influenced by a number of factors makes the characterization and prediction of these a difficult problem. In this study, the operating parameters on reaction between solid sorbent and CO2 gas at high temperature were investigated. The results of the breakthrough curves showed that calcium oxide sorbent in the fixed-bed reactor was capable of reducing the CO2 level to near zero level with the steam of 10 vol%, and the sorbent in CaO mixed with MgO of 40 wt% had extremely low capacity for CO2 capture at 550 deg. C. Calcium oxide sorbent after reaction can be easily regenerated at 900 deg. C by pure N2 flow. The experimental data were analyzed by shrinking core model, and the results showed reaction rates of both fresh and regeneration sorbents with CO2 were controlled by a combination of the surface chemical reaction and diffusion of product layer.

  8. Mechanochemically Activated, Calcium Oxide-Based, Magnesium Oxide-Stabilized Carbon Dioxide Sorbents.

    Science.gov (United States)

    Kurlov, Alexey; Broda, Marcin; Hosseini, Davood; Mitchell, Sharon J; Pérez-Ramírez, Javier; Müller, Christoph R

    2016-09-01

    Carbon dioxide capture and storage (CCS) is a promising approach to reduce anthropogenic CO2 emissions and mitigate climate change. However, the costs associated with the capture of CO2 using the currently available technology, that is, amine scrubbing, are considered prohibitive. In this context, the so-called calcium looping process, which relies on the reversible carbonation of CaO, is an attractive alternative. The main disadvantage of naturally occurring CaO-based CO2 sorbents, such as limestone, is their rapid deactivation caused by thermal sintering. Here, we report a scalable route based on wet mechanochemical activation to prepare MgO-stabilized, CaO-based CO2 sorbents. We optimized the synthesis conditions through a fundamental understanding of the underlying stabilization mechanism, and the quantity of MgO required to stabilize CaO could be reduced to as little as 15 wt %. This allowed the preparation of CO2 sorbents that exceed the CO2 uptake of the reference limestone by 200 %. PMID:27529608

  9. A calcium oxide sorbent process for bulk separation of carbon dioxide. Quarterly progress report 17, July--September 1993

    Energy Technology Data Exchange (ETDEWEB)

    Harrison, D.P.

    1993-10-01

    Phase II research involves a scale-up from microgram to gram quantities of sorbent and a switch from the electrobalance reactor to a fixed-bed reactor with capability for feed and product gas analysis. Parameters being studied in Phase II are essentially the same as in Phase I. The reactor response is being studied as a function of calcination and carbonation temperature and pressure, composition of the calcination and carbonation feed gas, and space velocity during the carbonation cycle. Multicycle tests are also being conducted to extend the information on sorbent durability. During the current quarter, reactor modifications to permit easier addition and removal of sorbent to and from the reactor were accomplished. It is now possible to remove sorbent after a run in discrete axial sections which will permit characterization of the sorbent as a function of axial position. Tracer response tests in which the chromatograph response to step function injections of hydrogen to flowing nitrogen under non-reactive conditions were carried out to evaluate the lag time between feeding reactive gases to the reactor and their appearance in the product gas sample. Fourteen additional calcination/carbonation reaction tests were completed this quarter, and the effects of carbonation background gas composition, sorbent particle size, calcination temperature, calcination gas flow rate, and calcination gas composition were studied. In addition, the first multicycle test involving complete calcination/carbonation cycles was carried out.

  10. Characterization of calcium carbonate sorbent particle in furnace environment

    International Nuclear Information System (INIS)

    The oxy-fuel combustion system is a promising technology to control CO2 and NOX emissions. Furthermore, sulfation reaction mechanism under CO2-rich atmospheric condition in a furnace may lead to in-furnace desulfurization. In the present study, we evaluated characteristics of calcium carbonate (CaCO3) sorbent particles under different atmospheric conditions. To examine the physical/chemical characteristics of CaCO3, which is used as a sorbent particle for in-furnace desulfurization in the oxy-fuel combustion system, they were injected into high temperature drop tube furnace (DTF). Experiments were conducted at varying temperatures, residence times, and atmospheric conditions in a reactor. To evaluate the aerosolizing characteristics of the CaCO3 sorbent particle, changes in the size distribution and total particle concentration between the DTF inlet and outlet were measured. Structural changes (e.g., porosity, grain size, and morphology) of the calcined sorbent particles were estimated by BET/BJH, XRD, and SEM analyses. It was shown that sorbent particles rapidly calcined and sintered in the air atmosphere, whereas calcination was delayed in the CO2 atmosphere due to the higher CO2 partial pressure. Instead, the sintering effect was dominant in the CO2 atmosphere early in the reaction. Based on the SEM images, it was shown that the reactions of sorbent particles could be explained as a grain–subgrain structure model in both the air and CO2 atmospheres.

  11. Characterization of calcium carbonate sorbent particle in furnace environment.

    Science.gov (United States)

    Lee, Kang Soo; Jung, Jae Hee; Keel, Sang In; Yun, Jin Han; Min, Tai Jin; Kim, Sang Soo

    2012-07-01

    The oxy-fuel combustion system is a promising technology to control CO₂ and NO(x) emissions. Furthermore, sulfation reaction mechanism under CO₂-rich atmospheric condition in a furnace may lead to in-furnace desulfurization. In the present study, we evaluated characteristics of calcium carbonate (CaCO₃) sorbent particles under different atmospheric conditions. To examine the physical/chemical characteristics of CaCO₃, which is used as a sorbent particle for in-furnace desulfurization in the oxy-fuel combustion system, they were injected into high temperature drop tube furnace (DTF). Experiments were conducted at varying temperatures, residence times, and atmospheric conditions in a reactor. To evaluate the aerosolizing characteristics of the CaCO₃ sorbent particle, changes in the size distribution and total particle concentration between the DTF inlet and outlet were measured. Structural changes (e.g., porosity, grain size, and morphology) of the calcined sorbent particles were estimated by BET/BJH, XRD, and SEM analyses. It was shown that sorbent particles rapidly calcined and sintered in the air atmosphere, whereas calcination was delayed in the CO₂ atmosphere due to the higher CO₂ partial pressure. Instead, the sintering effect was dominant in the CO₂ atmosphere early in the reaction. Based on the SEM images, it was shown that the reactions of sorbent particles could be explained as a grain-subgrain structure model in both the air and CO₂ atmospheres. PMID:22578525

  12. Characterization of calcium carbonate sorbent particle in furnace environment

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kang Soo [Aerosol and Particle Technology Laboratory, Department of Mechanical Engineering, KAIST 291 Daehak-ro, Yuseong-gu, Daejeon, 305-701 (Korea, Republic of); Jung, Jae Hee [Environment Sensor System Research Center, KIST 39-1 Hawolgok-dong, Seongbuk-gu, Seoul, 136-791 (Korea, Republic of); Keel, Sang In; Yun, Jin Han; Min, Tai Jin [Environmental Systems Research Division, KIMM 104 Sinseongno, Yuseong-gu, Daejeon, 305-343 (Korea, Republic of); Kim, Sang Soo, E-mail: sskim@kaist.ac.kr [Aerosol and Particle Technology Laboratory, Department of Mechanical Engineering, KAIST 291 Daehak-ro, Yuseong-gu, Daejeon, 305-701 (Korea, Republic of)

    2012-07-01

    The oxy-fuel combustion system is a promising technology to control CO{sub 2} and NO{sub X} emissions. Furthermore, sulfation reaction mechanism under CO{sub 2}-rich atmospheric condition in a furnace may lead to in-furnace desulfurization. In the present study, we evaluated characteristics of calcium carbonate (CaCO{sub 3}) sorbent particles under different atmospheric conditions. To examine the physical/chemical characteristics of CaCO{sub 3}, which is used as a sorbent particle for in-furnace desulfurization in the oxy-fuel combustion system, they were injected into high temperature drop tube furnace (DTF). Experiments were conducted at varying temperatures, residence times, and atmospheric conditions in a reactor. To evaluate the aerosolizing characteristics of the CaCO{sub 3} sorbent particle, changes in the size distribution and total particle concentration between the DTF inlet and outlet were measured. Structural changes (e.g., porosity, grain size, and morphology) of the calcined sorbent particles were estimated by BET/BJH, XRD, and SEM analyses. It was shown that sorbent particles rapidly calcined and sintered in the air atmosphere, whereas calcination was delayed in the CO{sub 2} atmosphere due to the higher CO{sub 2} partial pressure. Instead, the sintering effect was dominant in the CO{sub 2} atmosphere early in the reaction. Based on the SEM images, it was shown that the reactions of sorbent particles could be explained as a grain-subgrain structure model in both the air and CO{sub 2} atmospheres.

  13. Modeling of calcium-based sorbent reactions with sulfur dioxide

    Directory of Open Access Journals (Sweden)

    Tomanović Ivan

    2015-01-01

    Full Text Available A mathematical model of calcium sorbent reactions for simulation of sulfur dioxide reduction from pulverized coal combustion fl e gasses is developed, implemented within numerical code and validated against available measurements under controlled conditions. The model attempts to closely resemble reactions of calcination, sintering and sulfation, occurring during the sorbent particles motion in the furnace. The sulfation is based on PSSM (Partially Sintered Spheres Model, coupled with simulated particle calcination and sintering. Complex geometry of the particle is taken into account, with the assumption that it consists of spherical grains in contact with each other. Numerical simulations of drop down tube reactors were performed for both CaCO3 and Ca(OH2 sorbent particles and results were compared with available experimental data from literature. The sorbent reactions model will be further used for simulations of desulfurization reactions in turbulent gas-particle flow under coalcombustion conditions. [Projekat Ministarstva nauke Republike Srbije, br. TR-33018: Increase in energy and ecology efficiency of processes in pulverized coal-fired furnace and optimization of utility steam boiler air preheater by using in-house developed software tools

  14. Modelling of non-isothermal calcination, sintering and sulphation of calcium based sorbent particles at high temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Alvfors, P. (Dept. of Heat Technology, Royal Institute of Technology, Stockholm (SE))

    1990-01-01

    A model has been developed for the simulation of the chemical and physical processes taking place in a sorbent particle, consisting of limestone, or limestone with an inert content in the form of magnesium carbonate, injected into the furnace of a pulverized coal-fired or grate-fired boiler. This process is important since the reaction between limestone and the sulphur dioxide formed during the combustion of coal is one important way of sulphur capture. The characteristics of this process are: typical temperatures in the interval 900-1200 deg. C, short residence time and hence short available reaction time for the sorbent particles, 1-2 seconds, and small sorbent particles, typically less than 50 {mu}m. The model accounts for the three processes believed to be the major factors in determining the conversion of the calcium carbonate in the sorbent particles. These are: the calcination of the sorbent, which produces the reactive oxide through emittance of carbon dioxide, the sintering of the calcination product, leading to a decrease in the reactivity of the oxide through grain growth, and the sulphation of the reactive oxide. The sulphation model includes pore diffusion, diffusion through solid product layer and the chemical reaction on the active surface. The structural changes due to different molar volumes of reactant and product are accounted for as well as the influence that changing porosity has on the pore diffusion rate. Results from model simulations were compared with experimental data for verification. The model correctly predicts trends in conversion for different temperatures, sorbent particle sizes, sulphur dioxide concentrations, and inert content in the sorbent. It is a valuable tool for predicting the effects on the calcium conversion when changes are brought about in the parameters mentioned. (author) 17 refs.

  15. Investigation on durability and reactivity of promising metal oxide sorbents during sulfidation and regeneration. Quarterly report, October--December 1994

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, K.C.

    1995-01-01

    Hot-gas desulfurization for the integrated gasification combined cycle (IGCC) process has been investigated by many researchers to remove effectively hydrogen sulfide with various metal oxide sorbents at high pressures and high temperatures. Metal oxides such as zinc titanate oxides, zinc ferrite oxide, copper oxide, manganese oxide and calcium oxide, were found to be promising sorbents in comparison with other removal methods such as membrane separations and reactive membrane separations. Some metal oxide sorbents exhibited the quite favorable performance in terms of attrition resistance and sulfur capacity. Removal reaction of H{sub 2}S from coal gas mixtures with ZT-4 or other promising sorbents of fine solid particles, and regeneration reaction of sulfur-loaded sorbents will be carried on in a batch reactor or a continuous differential reactor. The objectives of this research project are to find intrinsic initial reaction kinetics for the metal oxide-hydrogen sulfide heterogeneous reaction system, to obtain effects of concentrations of coal gas components such as hydrogen, carbon monoxide, carbon dioxide, oxygen, nitrogen and moisture on equilibrium reaction rate constants of the reaction system at various reaction temperatures and pressures, to identify regeneration kinetics of sulfur-loaded metal oxide sorbents, and to formulate promising metal oxide sorbent for the removal of sulfur from coal gas mixtures. Promising durable metal oxide sorbents of high-sulfur-absorbing capacity will be formulated by mixing active metal oxide powders with inert metal oxide powders and calcining these powder mixtures, or impregnating active metal oxide sorbents on supporting metal oxide matrixes.

  16. Study of calcium chloride and calcium nitrate purification on inorganic sorbents

    International Nuclear Information System (INIS)

    Purification of calcium chloride and calcium nitrate from iron, chromium, manganese and cobalt impurities by sorption on some inorganic collectors are considered in this article. Study was conducted by means of radioactive-tracer technique at concurrent use of several γ-radioactive isotopes. As a collectors were used hydrated aluminium and zirconium oxides. Dependence of effectiveness of precipitation by collectors on ph-value of medium, quantity of collector, nature and concentration of components is studied. Optimal parameters of purification of calcium chloride and calcium nitrate are defined.

  17. Calcium looping spent sorbent as a limestone replacement in the manufacture of portland and calcium sulfoaluminate cements.

    Science.gov (United States)

    Telesca, Antonio; Marroccoli, Milena; Tomasulo, Michele; Valenti, Gian Lorenzo; Dieter, Heiko; Montagnaro, Fabio

    2015-06-01

    The calcium looping (CaL) spent sorbent (i) can be a suitable limestone replacement in the production of both ordinary Portland cement (OPC) and calcium sulfoaluminate (CSA) cement, and (ii) promotes environmental benefits in terms of reduced CO2 emission, increased energy saving and larger utilization of industrial byproducts. A sample of CaL spent sorbent, purged from a 200 kWth pilot facility, was tested as a raw material for the synthesis of two series of OPC and CSA clinkers, obtained from mixes heated in a laboratory electric oven within temperature ranges 1350°-1500 °C and 1200°-1350 °C, respectively. As OPC clinker-generating mixtures, six clay-containing binary blends were investigated, three with limestone (reference mixes) and three with the CaL spent sorbent. All of them showed similar burnability indexes. Moreover, three CSA clinker-generating blends (termed RM, MA and MB) were explored. They included, in the order: (I) limestone, bauxite and gypsum (reference mix); (II) CaL spent sorbent, bauxite and gypsum; (III) CaL spent sorbent plus anodization mud and a mixture of fluidized bed combustion (FBC) fly and bottom ashes. The maximum conversion toward 4CaO·3Al2O3·SO3, the chief CSA clinker component, was the largest for MB and almost the same for RM and MA. PMID:25915150

  18. Hydration products of FBC wastes as SO2 sorbents: comparison between ettringite and calcium hydroxide

    International Nuclear Information System (INIS)

    Fluidized bed combustion (FBC) enables the in situ capture of SO2, but generates large amounts of wastes whose composition and physico-chemical properties make both landfilling and reuse in traditional fields of application (e.g., cement and concrete industries) problematic. Reactivation by water hydration of the desulphurizing ability of these residues is considered a viable mean for their recycling: besides Ca(OH)2, this process can generate other hydration products, such as ettringite. This paper is devoted to a comparison between the behaviour of Ca(OH)2 and ettringite as SO2 sorbents. To this end, synthetic preparations (in the particle size range 0.4-0.6 mm) of the two materials were dehydrated and then sulphated in a lab-scale fluidized bed reactor. Sulphation tests were carried out at 850 C by fluidizing the bed with an SO2-N2-O2 mixture (1800 ppm SO2) at 0.8 m/s. Calcium conversion degree and fines elutriation rate were evaluated as a function of sulphation time. The propensity of the sorbents to undergo fragmentation was also estimated by particle sizing of in-bed exhausted sorbent particles, with the aid of laser granulometry. Mercury intrusion porosimetry of samples was directed to the assessment of the influence of sorbent dehydration and subsequent sulphation on pore size distribution and porosimetric texture. X-ray diffraction and differential thermal analysis on the synthetic sorbents complemented the characterization. Results showed that dehydration/thermal decomposition brought about a significant increase of the overall porosity for both sorbents, more extensive than it is commonly observed with calcined commercial limestones. Upon sulphation, the two sorbents showed satisfactory degrees of calcium conversion, larger than those usually observed with limestones. Sulphation resulted into a decrease of particle voidage (that of the Ca(OH)2-based sorbent was negligible after the process). Ettringite was more prone to attrition/fragmentation than

  19. Calcium-based sorbents behaviour during sulphation at oxy-fuel fluidised bed combustion conditions

    OpenAIRE

    García Labiano, Francisco; Rufas, Aránzazu; Diego Poza, Luis F. de; Obras-Loscertales, Margarita de las; Gayán Sanz, Pilar; Abad Secades, Alberto; Adánez Elorza, Juan

    2011-01-01

    Sulphur capture by calcium-based sorbents is a process highly dependent on the temperature and CO2 concentration. In oxy-fuel combustion in fluidised beds (FB), CO2 concentration in the flue gas may be enriched up to 95%. Under so high CO2 concentration, different from that in conventional coal combustion with air, the calcination and sulphation behaviour of the sorbent must be defined to determine the optimum operating temperature in the FB combustors. In this work, the SO2 retention capacit...

  20. SMALL-SCALE PILOT EVALUATION OF CALCIUM- AND SODIUM-BASED SORBENTS FOR DRY SO2 REMOVAL

    Science.gov (United States)

    The paper discusses a 100 cu m/h pilot facility (consisting of a spray dryer, a sorbent injection system, a duct section, and a pulse-jet baghouse or cyclone separator) used for testing the reaction at low temperature between various calcium- and sodium-based sorbents and SO2 in ...

  1. SE-SR with sorbents based on calcium aluminates: Process optimization

    International Nuclear Information System (INIS)

    Highlights: • State of the art and past experimental investigations were describe. • Feeding flow rate effect on SE-SR performance was investigated. • S/C and particle size effects on SE-SR performance were investigated. • CO2 capture capacity of M3 sorbent was compared to the state of the art. • Operating conditions of SE-SR process with M3 sorbent were optimized. - Abstract: The development of a sustainable power generation using fossil fuels will be strongly encouraged in the future in order to achieve European targets in terms of CO2 emissions. In this context, sorption-enhanced steam reforming (SE-SR) is a promising process that can be implemented as a CCS pre-combustion methodology. Regarding conventional catalyst-CO2 sorbent materials, main challenges concern the development of innovative CO2 sorbents with higher stability and regeneration temperature lower than CaO one. In recent study, a high-performance material based on incorporation of CaO particles into calcium aluminates was developed by authors exhibiting high sorption capacity and stability in multi cycle process. In this study, such a sorbent was packed, together with the catalyst, in a fixed bed reactor and tested in multi-cycle SE-SR process optimizing the operating conditions. Sensitivity analysis was carried out in reference to feeding flow rate, steam to carbon molar ratio and material particle size. The innovative sorbent exhibits, in optimized process, significant performance improvements (in terms of H2 purity and total CO2 amount adsorbed in each carbonation cycle) respect similar approaches available in the technical literature

  2. Mercury removal sorbents

    Energy Technology Data Exchange (ETDEWEB)

    Alptekin, Gokhan

    2016-03-29

    Sorbents and methods of using them for removing mercury from flue gases over a wide range of temperatures are disclosed. Sorbent materials of this invention comprise oxy- or hydroxyl-halogen (chlorides and bromides) of manganese, copper and calcium as the active phase for Hg.sup.0 oxidation, and are dispersed on a high surface porous supports. In addition to the powder activated carbons (PACs), this support material can be comprised of commercial ceramic supports such as silica (SiO.sub.2), alumina (Al.sub.2O.sub.3), zeolites and clays. The support material may also comprise of oxides of various metals such as iron, manganese, and calcium. The non-carbon sorbents of the invention can be easily injected into the flue gas and recovered in the Particulate Control Device (PCD) along with the fly ash without altering the properties of the by-product fly ash enabling its use as a cement additive. Sorbent materials of this invention effectively remove both elemental and oxidized forms of mercury from flue gases and can be used at elevated temperatures. The sorbent combines an oxidation catalyst and a sorbent in the same particle to both oxidize the mercury and then immobilize it.

  3. Sulphation of calcium-based sorbents in circulating fluidised beds under oxy-fuel combustion conditions

    Energy Technology Data Exchange (ETDEWEB)

    Francisco Garcia-Labiano; Luis F. de Diego; Alberto Abad; Pilar Gayan; Margarita de las Obras-Loscertales; Aranzazu Rufas; Juan Adanez [Instituto de Carboquimica (CSIC), Zaragoza (Spain). Dept. Energy and Environment

    2009-07-01

    Sulphur Retention (SR) by calcium-based sorbents is a process highly dependent on the temperature and CO{sub 2} concentration. In circulating fluidised beds combustors (CFBC's) operating under oxy-fuel conditions, the sulphation process takes place in atmospheres enriched in CO{sub 2} with bed concentrations that can vary from 40 to 95%. Under so high CO{sub 2} concentrations, very different from that in conventional coal combustion atmosphere with air, the calcination and sulphation behaviour of the sorbent must be defined to optimise the SR process in the combustor. The objective of this work was to determine the SO{sub 2} retention capacity of a Spanish limestone at typical oxy-fuel conditions in CFBC's. Long term duration tests of sulphation (up to 24 h), to simulate the residence time of sorbents in CFBC's, were carried out by thermogravimetric analysis (TGA). Clear behaviour differences were found under calcining and non-calcining conditions. Especially relevant was the result obtained at calcining conditions but close to the thermodynamic temperature given for sorbent calcination. This situation must be avoided in CFBC's because the CO{sub 2} produced inside the particle during calcination can destroy the particles if a non-porous sulphate product layer has been formed around the particle. The effect of the main variables on the sorbent sulphation such as SO{sub 2} concentration, temperature, and particle size were analysed in the long term TGA tests. These data were also used to determine the kinetic parameters for the sulphation under oxy-fuel combustion conditions, which were able to adequately predict the sulphation conversion values in a wide range of operating conditions. 20 refs., 5 figs., 2 tabs.

  4. Desulfurization sorbent regeneration

    Science.gov (United States)

    Jalan, V.M.; Frost, D.G.

    1982-07-07

    A spent solid sorbent resulting from the removal of hydrogen sulfide from a fuel gas flow is regenerated with a steam-air mixture. The mixture of steam and air may also include additional nitrogen or carbon dioxide. The gas mixture contacts the spent sorbent containing metal sulfide at a temperature above 500/sup 0/C to regenerate the sulfide to metal oxide or carbonate. Various metal species including the period four transition metals and the lanthanides are suitable sorbents that may be regenerated by this method. In addition, the introduction of carbon dioxide gas permits carbonates such as those of strontium, barium and calcium to be regenerated. The steam permits regeneration of spent sorbent without formation of metal sulfate. Moreover, the regeneration will proceed with low oxygen concentrations and will occur without the increase in temperature to minimize the risk of sintering and densification of the sorbent. This method may be used for high-temperature fuel cells.

  5. Sorbents for the oxidation and removal of mercury

    Energy Technology Data Exchange (ETDEWEB)

    Olson, Edwin S.; Holmes, Michael J.; Pavlish, John Henry

    2014-09-02

    A promoted activated carbon sorbent is described that is highly effective for the removal of mercury from flue gas streams. The sorbent comprises a new modified carbon form containing reactive forms of halogen and halides. Optional components may be added to increase reactivity and mercury capacity. These may be added directly with the sorbent, or to the flue gas to enhance sorbent performance and/or mercury capture. Mercury removal efficiencies obtained exceed conventional methods. The sorbent can be regenerated and reused. Sorbent treatment and preparation methods are also described. New methods for in-flight preparation, introduction, and control of the active sorbent into the mercury contaminated gas stream are described.

  6. Sorbents for the oxidation and removal of mercury

    Science.gov (United States)

    Olson, Edwin S.; Holmes, Michael J.; Pavlish, John H.

    2012-05-01

    A promoted activated carbon sorbent is described that is highly effective for the removal of mercury from flue gas streams. The sorbent comprises a new modified carbon form containing reactive forms of halogen and halides. Optional components may be added to increase reactivity and mercury capacity. These may be added directly with the sorbent, or to the flue gas to enhance sorbent performance and/or mercury capture. Mercury removal efficiencies obtained exceed conventional methods. The sorbent can be regenerated and reused. Sorbent treatment and preparation methods are also described. New methods for in-flight preparation, introduction, and control of the active sorbent into the mercury contaminated gas stream are described.

  7. Sorbents for the oxidation and removal of mercury

    Science.gov (United States)

    Olson, Edwin S.; Holmes, Michael J.; Pavlish, John H.

    2008-10-14

    A promoted activated carbon sorbent is described that is highly effective for the removal of mercury from flue gas streams. The sorbent comprises a new modified carbon form containing reactive forms of halogen and halides. Optional components may be added to increase reactivity and mercury capacity. These may be added directly with the sorbent, or to the flue gas to enhance sorbent performance and/or mercury capture. Mercury removal efficiencies obtained exceed conventional methods. The sorbent can be regenerated and reused. Sorbent treatment and preparation methods are also described. New methods for in-flight preparation, introduction, and control of the active sorbent into the mercury contaminated gas stream are described.

  8. Effects of rapid calcination on properties of calcium-based sorbents

    International Nuclear Information System (INIS)

    The calcination process may influence subsequent fragmentation, sintering and swelling when CaO derived from limestone acts as a CO2 or SO2-sorbent in combustion, gasification and reforming. Sorbent properties are affected by CO2 partial pressure, total pressure, temperature, heating rate, impurities and sample size. In this study, the effect of calcination heating rate was investigated based on an electrically heated platinum foil. The effects of heating rate (up to 800 C/s), calcination temperature (700-950 C), particle size (90-180 μm) and sweep gas velocity were investigated. Higher initial heating rates led to lower extents of limestone calcination, but the extents of carbonation of the resulting CaO were similar to each other. Calcium utilization declined markedly during carbonation or sulphation of CaO after calcination by rapid heating. Experimental results show that carbonation and calcium utilization were most effective for carbonation temperatures between 503 and 607 C. Increasing the extent of calcination is not the best way to improve overall calcium utilization due to the vast increase in energy consumption. (author)

  9. NOVEL MERCURY OXIDANT AND SORBENT FOR MERCURY EMISSIONS CONTROL FROM COAL-FIRED POWER PLANTS

    Science.gov (United States)

    The authors have successfully developed novel efficient and cost-effective sorbent and oxidant for removing mercury from power plant flue gases. These sorbent and oxidant offer great promise for controlling mercury emissions from coal-fired power plants burning a wide range of c...

  10. Nanostructured Metal Oxide Sorbents for the Collection and Recovery of Uranium from Seawater

    Energy Technology Data Exchange (ETDEWEB)

    Chouyyok, Wilaiwan; Warner, Cynthia L.; Mackie, Katherine E.; Warner, Marvin G.; Gill, Gary A.; Addleman, Raymond S.

    2016-02-07

    The ability to collect uranium from seawater offers the potential for a long-term green fuel supply for nuclear energy. However, extraction of uranium, and other trace minerals, is challenging due to the high ionic strength and low mineral concentrations in seawater. Herein we evaluate the use of nanostructured metal oxide sorbents for the collection and recovery of uranium from seawater. Chemical affinity, chemical adsorption capacity and kinetics of preferred sorbent materials were evaluated. High surface area manganese and iron oxide nanomaterials showed excellent performance for uranium collection from seawater. Inexpensive nontoxic carbonate solutions were demonstrated to be an effective and environmental benign method of stripping the uranium from the metal oxide sorbents. Various formats for the utilization of the nanostructured metals oxide sorbent materials are discussed including traditional and nontraditional methods such as magnetic separation. Keywords: Uranium, nano, manganese, iron, sorbent, seawater, magnetic, separations, nuclear energy

  11. Zinc-oxide-based sorbents and processes for preparing and using same

    Science.gov (United States)

    Gangwal, Santosh Kumar; Turk, Brian Scott; Gupta, Raghubir Prasael

    2010-03-23

    Zinc oxide-based sorbents, and processes for preparing and using them are provided. The sorbents are preferably used to remove one or more reduced sulfur species from gas streams. The sorbents comprise an active zinc component, optionally in combination with one or more promoter components and/or one or more substantially inert components. The active zinc component is a two phase material, consisting essentially of a zinc oxide (ZnO) phase and a zinc aluminate (ZnAl.sub.2O.sub.4) phase. Each of the two phases is characterized by a relatively small crystallite size of typically less than about 500 Angstroms. Preferably the sorbents are prepared by converting a precursor mixture, comprising a precipitated zinc oxide precursor and a precipitated aluminum oxide precursor, to the two-phase, active zinc oxide containing component.

  12. CO2 capture performance of calcium-based sorbent doped with manganese salts during calcium looping cycle

    International Nuclear Information System (INIS)

    Graphical abstract: Comparison of carbonation conversions of Mn-doped and original CaCO3 during long-term cycles for calcination at 850 oC and carbonation at 700 oC. The Mn/Ca molar ratio is 1/100 and 1.5/100 for Mn(NO3)2-doped and MnCO3-doped CaCO3, respectively. Highlights: → We modified CaCO3 with manganese salts including Mn(NO3)2 and MnCO3. → The CO2 capture capacity during multiple cycles is enhanced by modification. → Mn-doped sorbents keep better pore structure during calcium looping cycles. → The improvements of Mn(NO3)2 and MnCO3 on CO2 capture capacity are almost the same. -- Abstract: The effects of manganese salts including Mn(NO3)2 and MnCO3 on CO2 capture performance of calcium-based sorbent during cyclic calcination/carbonation reactions were investigated. Mn(NO3)2 and MnCO3 were added by wet impregnation method. The cyclic CO2 capture capacities of Mn(NO3)2-doped CaCO3, MnCO3-doped CaCO3 and original CaCO3 were studied in a twin fixed-bed reactor and a thermo-gravimetric analyzer (TGA), respectively. The results show that the addition of manganese salts improves the cyclic carbonation conversions of CaCO3 except the previous cycles. When the Mn/Ca molar ratios are 1/100 for Mn(NO3)2-doped CaCO3 and 1.5/100 for MnCO3-doped CaCO3, the highest carbonation conversions are achieved respectively. The carbonation temperature of 700-720 oC is beneficial to CO2 capture of Mn-doped CaCO3. The residual carbonation conversions of Mn(NO3)2-doped and MnCO3-doped CaCO3 are 0.27 and 0.24 respectively after 100 cycles, compared with the conversion of 0.16 for original one after the same number of cycles. Compared with calcined original CaCO3, better pore structure is kept for calcined Mn-doped CaCO3 during calcium looping cycle. The pore volume of calcined MnCO3-doped CaCO3 is 2.4 times as high as that of calcined original CaCO3 after 20 cycles. The pores of calcined MnCO3-doped CaCO3 in the pore size range of 27-142 nm are more abundant relative to

  13. CO{sub 2} capture efficiency and energy requirement analysis of power plant using modified calcium-based sorbent looping cycle

    Energy Technology Data Exchange (ETDEWEB)

    Li, Y.J.; Zhao, C.S.; Chen, H.C.; Ren, Q.Q.; Duan, L.B. [Southeast University, Nanjing (China). School of Energy & Environment

    2011-03-15

    This paper examines the average carbonation conversion, CO{sub 2} capture efficiency and energy requirement for post-combustion CO{sub 2} capture system during the modified calcium-based sorbent looping cycle. The limestone modified with acetic acid solution, i.e. calcium acetate is taken as an example of the modified calcium-based sorbents. The modified limestone exhibits much higher average carbonation conversion than the natural sorbent under the same condition. The CO{sub 2} capture efficiency increases with the sorbent flow ratios. Compared with the natural limestone, much less makeup mass flow of the recycled and the fresh sorbent is needed for the system when using the modified limestone at the same CO{sub 2} capture efficiency. Achieving 0.95 of CO{sub 2} capture efficiency without sulfation, 272 kJ/mol CO{sub 2} is required in the calciner for the natural limestone, whereas only 223 kJ/mol CO{sub 2} for the modified sorbent. The modified limestone possesses greater advantages in CO{sub 2} capture efficiency and energy consumption than the natural sorbent. When the sulfation and carbonation of the sorbents take place simultaneously, more energy is required. It is significantly necessary to remove SO{sub 2} from the flue gas before it enters the carbonator in order to reduce energy consumption in the calciner.

  14. Application of a sorbent trap system to gas-phase elemental and oxidized mercury analysis.

    Science.gov (United States)

    Zhang, Zishuo; Eom, Yujin; Lee, Michelle J; Lee, Tai Gyu

    2016-07-01

    A sorbent trap that utilizes activated carbon (AC) as the solid trapping medium is a new technology for measuring total mercury (Hg) emissions from combustion facilities. In this study, sorbent trap technology was further developed, improved and evaluated at the laboratory scale. AC was impregnated with 5% aqua regia to enhance its Hg adsorption capacity. Sorbent traps spiked with an Hg standard solution were found to be reproducibly prepared and highly stable. The effect of the Hg concentration on the spiking efficiency was further investigated. The adsorption of elemental and oxidized Hg by the sorbent trap was studied under various experimental conditions (temperature, flow rate and inlet Hg concentration). The Hg concentration of the flue gas effluent from the sorbent trap was measured. In addition, the concentration of Hg adsorbed on the AC was determined by digesting the used AC with an acid according to US EPA method 3052 and then analyzing it with cold vapor atomic absorption spectrometry. Furthermore, the gas-phase Hg emissions from a combustion source were measured using the sorbent trap according to US EPA method 30B. The results showed that the sorbent trap could be used for Hg concentrations between 10.0 and 40.0 μg m(-3) and flow rates between 0.5 and 1.0 lpm with adsorption efficiencies greater than 90%. PMID:27060637

  15. Effect of the presence of HCl on cyclic CO2 capture of calcium-based sorbent in calcium looping process

    International Nuclear Information System (INIS)

    Highlights: • HCl improves CO2 capture capacity of limestone in the previous a dozen cycles. • HCl sharply decreases limestone reactivity after a dozen cycles. • HCl intensifies effects of carbonation and calcination temperature on CO2 capture. • HCl enlarges effects of particle size on CO2 capture. • HCl severely aggravates the sintering of limestone after a dozen cycles. - Abstract: The effect of the presence of HCl on cyclic CO2 capture behavior of calcium-based sorbent in the calcium looping process was investigated. When HCl was present in the carbonation atmosphere, the effects of carbonation temperature, calcination temperature, HCl concentration and particle size on CO2 capture of the limestone in the multiple calcination/carbonation cycles were studied in a dual fixed-bed reactor. The presence of HCl in the carbonation atmosphere improves CO2 capture capacity of the limestone in the previous a dozen cycles, but sharply decreases its reactivity with further increasing the cycle number above a dozen. The presence of HCl intensifies the effects of carbonation temperature and calcination temperature on CO2 capture capacity of the limestone. The optimum carbonation temperature and the feasible calcination temperature for cyclic CO2 capture of the limestone in the presence of HCl should be 700 °C and below 900 °C, respectively. The cyclic CO2 capture capacity of the limestone in the previous a dozen cycles achieves the maximum in the presence of 300 ppm HCl with increasing the HCl concentration from 100 to 1000 ppm. The higher CO2 capture capacity of the limestone is achieved with smaller particle size in the presence of HCl. The presence of HCl may destroy the compact CaCO3 product layer and it is beneficial to CO2 diffusion through the layer in the initial cycles. The chlorination conversion and the molten CaCl2–CaCO3 product layer thickness of the limestone in the presence of HCl increase with the number of calcination/carbonation cycles. It

  16. CO2 separation by calcium looping from full and partial fuel oxidation processes

    OpenAIRE

    Sivalingam, Senthoorselvan

    2013-01-01

    This thesis work deals with the research and development of Calcium Looping(CaL) process for CO2 separation from full and partial fuel oxidation based power generation systems. CaL process involves separation of CO2 at high temperatures (600-700°C) by calcium sorbents (CaO). CO2 reacts with CaO in a carbonation process and produces CaCO3. In a subsequent thermal regeneration (>850°C) called calcination, the CO2 is released from CaCO3. Moreover, the CaL is realised in industrial scale with dua...

  17. Ecological comparison of calcium hydroxide and sodium hydrogen carbonate as sorbents; Oekologischer Vergleich der Sorptionsmittel Calciumhydroxid und Natriumhydrogencarbonat

    Energy Technology Data Exchange (ETDEWEB)

    Pacher, Christian; Weber-Blaschke, Gabriele [Technische Univ. Muenchen, Freising (Germany). Lehrstuhl fuer Rohstoff- und Energietechnologie; Mocker, Mario [ATZ Entwicklungszentrum, Sulzbach-Rosenberg (Germany); Faulstich, Martin [Technische Univ. Muenchen, Straubing (Germany). Wissenschaftszentrum Straubing

    2009-07-01

    Lime products have long been used with success for flue gas purification in waste incineration plants, where they serve to eliminate acid gas pollutants such as sulphur dioxide, hydrogen chloride and hydrogen fluoride. This article presents excerpts of a study commissioned by the German lime industry association for the purpose of obtaining an unbiased well-founded comparison of the environmental impact of the two sorbents calcium hydroxide and sodium hydrogen carbonate. The following questions were addressed by the study: Which of the two flue gas additives provides greater environmental benefit under specified conditions? What parameters influence the outcome? How can the results be viewed in regard to different plant configurations?.

  18. 21 CFR 184.1210 - Calcium oxide.

    Science.gov (United States)

    2010-04-01

    ... specifications of the Food Chemicals Codex, 3d Ed. (1981), p. 55, which is incorporated by reference. Copies are... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium oxide. 184.1210 Section 184.1210 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR...

  19. Barium oxide, calcium oxide, magnesia, and alkali oxide free glass

    Science.gov (United States)

    Lu, Peizhen Kathy; Mahapatra, Manoj Kumar

    2013-09-24

    A glass composition consisting essentially of about 10-45 mole percent of SrO; about 35-75 mole percent SiO.sub.2; one or more compounds from the group of compounds consisting of La.sub.2O.sub.3, Al.sub.2O.sub.3, B.sub.2O.sub.3, and Ni; the La.sub.2O.sub.3 less than about 20 mole percent; the Al.sub.2O.sub.3 less than about 25 mole percent; the B.sub.2O.sub.3 less than about 15 mole percent; and the Ni less than about 5 mole percent. Preferably, the glass is substantially free of barium oxide, calcium oxide, magnesia, and alkali oxide. Preferably, the glass is used as a seal in a solid oxide fuel/electrolyzer cell (SOFC) stack. The SOFC stack comprises a plurality of SOFCs connected by one or more interconnect and manifold materials and sealed by the glass. Preferably, each SOFC comprises an anode, a cathode, and a solid electrolyte.

  20. Effect of rice husk ash addition on CO2 capture behavior of calcium-based sorbent during calcium looping cycle

    International Nuclear Information System (INIS)

    Rice husk ash/CaO was proposed as a CO2 sorbent which was prepared by rice husk ash and CaO hydration together. The CO2 capture behavior of rice husk ash/CaO sorbent was investigated in a twin fixed bed reactor system, and its apparent morphology, pore structure characteristics and phase variation during cyclic carbonation/calcination reactions were examined by SEM-EDX, N2 adsorption and XRD, respectively. The optimum preparation conditions for rice husk ash/CaO sorbent are hydration temperature of 75 C, hydration time of 8 h, and mole ratio of SiO2 in rice husk ash to CaO of 1.0. The cyclic carbonation performances of rice husk ash/CaO at these preparation conditions were compared with those of hydrated CaO and original CaO. The temperature at 660 C-710 C is beneficial to CO2 absorption of rice husk ash/CaO, and it exhibits higher carbonation conversions than hydrated CaO and original CaO during multiple cycles at the same reaction conditions. Rice husk ash/CaO possesses better anti-sintering behavior than the other sorbents. Rice husk ash exhibits better effect on improving cyclic carbonation conversion of CaO than pure SiO2 and diatomite. Rice husk ash/CaO maintains higher surface area and more abundant pores after calcination during the multiple cycles; however, the other sorbents show a sharp decay at the same reaction conditions. Ca2SiO4 found by XRD detection after calcination of rice husk ash/CaO is possibly a key factor in determining the cyclic CO2 capture behavior of rice husk ash/CaO. (author)

  1. Sulfidation and reduction of zinc titanate and zinc oxide sorbents for injection in gasifier exit ducts

    Energy Technology Data Exchange (ETDEWEB)

    Ishikawa, K. [Tufts Univ., Medford, MA (United States). Dept. of Chemical Engineering]|[Kawasaki Heavy Industries Ltd., Akashi, Hyogo (Japan). Technical Inst.; Krueger, C.; Flytzani-Stephanopoulos, M. [Tufts Univ., Medford, MA (United States). Dept. of Chemical Engineering; Jl, W.; Higgins, R.J.; Bishop, B.A.; Goldsmith, R.L. [CeraMem Corp., Waltham, MA (United States)

    1995-12-31

    The sulfidation reaction kinetics of fine particles of zinc titanate and zinc oxide with H{sub 2}S were studied in order to test the potential of the sorbent injection hot-gas desulfurization process. Fine sorbent particles with diameter between 0.3 and 60 {mu}m were sulfided with H{sub 2}S and/or reduced with H{sub 2} in a laminar flow reactor over the temperature range of 500-900{degrees}C. Sulfidation/reduction conversion was compared for different particle sizes and sorbents with various porosities and atomic ratios of Zn and Ti. In reduction of ZnO with H{sub 2} and without H{sub 2}S, significant amount of Zn was formed and vaporized, while the presence of H{sub 2}S suppressed elemental Zn formation. This suggests that H{sub 2}S may suppress the surface reduction of ZnO and/or gaseous Zn may react with H{sub 2}S homogeneously and form fine particles of ZnS. Formation and vaporization of elemental Zn from zinc titanate sorbents was slower than from zinc oxide with and without H{sub 2}S.

  2. THE COMPARISON OF SEVERAL STANDARD MATERIALS AND TECHNIQUES FOR THE WARREN-AVERBACH DETERMINATION OF MICRO-STRUCTURE CHARACTERISTICS OF CALCIUM HYDROXIDE SORBENT MATERIALS

    Science.gov (United States)

    The paper gives results of a comparison of several standard materials and techniques for the Warren-Averbach determination of microstructure characteristics of calcium hydroxide--Ca(OH)2--sorbent materials. The comparison is part of an investigation of the injection of dry Ca(OH)...

  3. Highly efficient CO2 sorbents: development of synthetic, calcium-rich dolomites.

    Science.gov (United States)

    Filitz, Rainer; Kierzkowska, Agnieszka M; Broda, Marcin; Müller, Christoph R

    2012-01-01

    The reaction of CaO with CO(2) is a promising approach for separating CO(2) from hot flue gases. The main issue associated with the use of naturally occurring CaCO(3), that is, limestone, is the rapid decay of its CO(2) capture capacity over repeated cycles of carbonation and calcination. Interestingly, dolomite, a naturally occurring equimolar mixture of CaCO(3) and MgCO(3), possesses a CO(2) uptake that remains almost constant with cycle number. However, owing to the large quantity of MgCO(3) in dolomite, the total CO(2) uptake is comparatively small. Here, we report the development of a synthetic Ca-rich dolomite using a coprecipitation technique, which shows both a very high and a stable CO(2) uptake over repeated cycles of calcination and carbonation. To obtain such an excellent CO(2) uptake characteristic it was found to be crucial to mix the Ca(2+) and Mg(2+) on a molecular level, that is, within the crystalline lattice. For sorbents which were composed of mixtures of microscopic crystals of CaCO(3) and MgCO(3), a decay behavior similar to natural limestone was observed. After 15 cycles, the CO(2) uptake of the best sorbent was 0.51 g CO(2)/g sorbent exceeding the CO(2) uptake of limestone by almost 100%. PMID:22129091

  4. CO{sub 2} separation by calcium looping from full and partial fuel oxidation processes

    Energy Technology Data Exchange (ETDEWEB)

    Sivalingam, Senthoorselvan

    2013-06-05

    This thesis work deals with the research and development of calcium looping process for CO{sub 2} separation from full and partial fuel oxidation based power generation systems. CO{sub 2} is the main greenhouse gas and undoubtedly a major contributor to the global warming. It is estimated that more than one third of the total anthropogenic CO{sub 2} emissions come from fossil fuel based heat and power generation. Moreover, fossil fuels are unlikely to be phased out rapidly, since developing alternative energy sources not only take time but also require huge investments and infrastructure. An alternative way to reduce emissions in a medium term is to capture the CO{sub 2} from fossil fueled power plants and store it away from the atmosphere. This process system combining a bunch of technologies is called carbon capture and storage (CCS). CO{sub 2} capture is an important and costly part of CCS and an array of technologies is considered for this. Calcium looping (CaL) is one of such and seems to offer effective and efficient CO{sub 2} separation from fuel oxidation processes. CaL process involves separation of CO{sub 2} at high temperatures (600-700 C) by calcium sorbents (CaO). CO{sub 2} reacts with CaO in a carbonation process and produces CaCO{sub 3}. In a subsequent thermal regeneration (>850 C) called calcination, the CO{sub 2} is released from CaCO{sub 3}. By alternating carbonations and calcinations over multiple cycles, CO{sub 2} is separated from a gas stream. Moreover, the CaL is realised in industrial scale with dual fluidised bed reactors for CO{sub 2} capture (the carbonator) and sorbent regeneration (the calciner). As a process in the development, research is still required in many aspects from thermodynamic modeling to experimental studies. Research works have been carried out in process simulations, sorbent reactivity and optimisation studies in a controlled reactor environment and process parametric studies in a semi-pilot scale CaL test facility

  5. CO2 separation by calcium looping from full and partial fuel oxidation processes

    International Nuclear Information System (INIS)

    This thesis work deals with the research and development of calcium looping process for CO2 separation from full and partial fuel oxidation based power generation systems. CO2 is the main greenhouse gas and undoubtedly a major contributor to the global warming. It is estimated that more than one third of the total anthropogenic CO2 emissions come from fossil fuel based heat and power generation. Moreover, fossil fuels are unlikely to be phased out rapidly, since developing alternative energy sources not only take time but also require huge investments and infrastructure. An alternative way to reduce emissions in a medium term is to capture the CO2 from fossil fueled power plants and store it away from the atmosphere. This process system combining a bunch of technologies is called carbon capture and storage (CCS). CO2 capture is an important and costly part of CCS and an array of technologies is considered for this. Calcium looping (CaL) is one of such and seems to offer effective and efficient CO2 separation from fuel oxidation processes. CaL process involves separation of CO2 at high temperatures (600-700 C) by calcium sorbents (CaO). CO2 reacts with CaO in a carbonation process and produces CaCO3. In a subsequent thermal regeneration (>850 C) called calcination, the CO2 is released from CaCO3. By alternating carbonations and calcinations over multiple cycles, CO2 is separated from a gas stream. Moreover, the CaL is realised in industrial scale with dual fluidised bed reactors for CO2 capture (the carbonator) and sorbent regeneration (the calciner). As a process in the development, research is still required in many aspects from thermodynamic modeling to experimental studies. Research works have been carried out in process simulations, sorbent reactivity and optimisation studies in a controlled reactor environment and process parametric studies in a semi-pilot scale CaL test facility. ASPEN Plus power plant simulations integrating the CaL based CO2 capture

  6. Calcium-looping for post-combustion CO2 capture. On the adverse effect of sorbent regeneration under CO2

    International Nuclear Information System (INIS)

    Highlights: • Carbonation/calcination tests are reported in which the sorbent is regenerated under high CO2 partial pressure. • A drastic drop of CaO conversion occurs in just a few carbonation/calcination cycles. • Recarbonation has an adverse effect. • The growth of the CaO crystal structure along reactive oriented surfaces is precluded. • The presence of H2O would counteract the adverse effect of regeneration under CO2. - Abstract: The multicyclic carbonation/calcination (c/c) of CaO solid particles at high temperature is at the basis of the recently emerged Calcium-looping (CaL) technology, which has been shown to be potentially suitable for achieving high and sustainable post-combustion CO2 capture efficiency. Despite the success of pilot plant projects at the MWth scale, a matter of concern for scaling-up the CaL technology to a commercial level (to the GWth scale) is that the CaO carbonation reactivity can be recovered only partially when the sorbent is regenerated by calcination at high temperatures (around 950 °C) as required by the CO2 high concentration in the calciner. In order to reactivate the sorbent, a novel CaL concept has been proposed wherein a recarbonator reactor operated at high temperature/high CO2 concentration leads to further carbonation of the solids before entering into the calciner for regeneration. Multicyclic thermogravimetric analysis (TGA) tests demonstrate the feasibility of recarbonation to reactivate the sorbent regenerated at high calcination temperatures yet at unrealistically low CO2 partial pressure mainly because of technical limitations concerning low heating/cooling rates. We report results from multicyclic c/c and carbonation/recarbonation/calcination (c/r/c) TGA tests at high heating/coling rates and in which the sorbent is regenerated in a dry atmosphere at high CO2 partial pressure. It is shown that at these conditions there is a drastic drop of CaO conversion to a very small residual value in just a few

  7. Graphene oxide-polamides as a sorbent of radioactive ions

    Czech Academy of Sciences Publication Activity Database

    Schelonka, Darina; Štengl, Václav; Tolasz, Jakub; Ecorchard, Petra

    Aveiro : University of Aveiro, 2015. [International conference on Advanced Nanomaterials /6./, International conference on Graphene Technology /1./, International conference on Hydrogen Energy /1./ - ANM2015. 20.07.2015-22.07.2015, Aveiro] R&D Projects: GA TA ČR(CZ) TA04020222 Institutional support: RVO:61388980 Keywords : Graphene oxide-polamides Subject RIV: CA - Inorganic Chemistry http://www.anm2015.com/wp-content/uploads/2015/07/GT-abstract-Book-Final.pdf

  8. INVESTIGATION OF MIXED METAL SORBENT/CATALYSTS FOR THE SIMULTANEOUS REMOVAL OF SULFUR AND NITROGEN OXIDES; FINAL

    International Nuclear Information System (INIS)

    Simultaneous removal of SO(sub 2) and NO(sub x) using a regenerable solid sorbent will constitute an important improvement over the use of separate processes for the removal of these two pollutants from stack gases and possibly eliminate several shortcomings of the individual SO(sub 2) and NO(sub x) removal operations. The work done at PETC and the DOE-funded investigation of the investigators on the sulfation and regeneration of alumina-supported cerium oxide sorbents have shown that they can perform well at relatively high temperatures (823-900 K) as regenerable desulfurization sorbents. Survey of the recent literature shows that addition of copper oxide to ceria lowers the sulfation temperature of ceria down to 773 K, sulfated ceria-based sorbents can function as selective SCR catalysts even at elevated temperatures, SO(sub 2) can be directly reduced to sulfur by CO on CuO-ceria catalysts, and ceria-based catalysts may have a potential for selective catalytic reduction of NO(sub x) by methane. These observations indicate a possibility of developing a ceria-based sorbent/catalyst which can remove both SO(sub 2) and NO(sub x) from flue gases within a relatively wide temperature window, produce significant amounts of elemental sulfur during regeneration, and use methane for the selective catalytic reduction of NO(sub x)

  9. 40 CFR 721.10011 - Barium calcium manganese strontium oxide.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Barium calcium manganese strontium... Specific Chemical Substances § 721.10011 Barium calcium manganese strontium oxide. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as barium...

  10. Effect of inhibitors on macroscopical oxidation kinetics of calcium sulfite

    Institute of Scientific and Technical Information of China (English)

    ZHAO Yi; WANG Li-dong; WANG Xiao-ming; LI Qiang-wei; XU Pei-yao

    2005-01-01

    In the presence of inhibitors, the macroscopical oxidation kinetics of calcium sulfite, the main byproduct in wet limestone scrubbing, was studied for the first time by adding different inhibitors and varying pH, concentration of calcium sulfite, oxygen partial pressure, concentration of inhibitors and temperature. The mathematical model about the general oxidation reaction was established,which was controlled by three steps involving dissolution of calcium sulfite, mass transfer of oxygen and chemical reaction in the solution.It was concluded that the general reaction was controlled by mass transfer of oxygen under uncatalyzed conditions, while it was controlled by dissolution of calcium sulfite after adding three kinds of inhibitors. Thus, the theory was provided for investigating the mechanism and oxidation kinetics of sulfite. The beneficial references were also supplied for design of oxidation technics in the wet limestone scrubbing.

  11. Heterogeneous nucleation of calcium oxalate on native oxide surfaces

    International Nuclear Information System (INIS)

    The aqueous deposition of calcium oxalate onto colloidal oxides has been studied as a model system for understanding heterogeneous nucleation processes of importance in biomimetic synthesis of ceramic thin films. Calcium oxalate nucleation has been monitored by measuring induction times for nucleation using Constant Composition techniques and by measuring nucleation densities on extended oxide surfaces using an atomic force microscope. Results show that the dependence of calcium oxalate nucleation on solution supersaturation fits the functional form predicted by classical nucleation theories. Anionic surfaces appear to promote nucleation better than cationic surfaces, lowering the effective energy barrier to heterogeneous nucleation

  12. Experimental kinetic study and modeling of calcium oxide carbonation

    International Nuclear Information System (INIS)

    Anthropogenic carbon dioxide (CO2) emissions, major contributors to the greenhouse effect, are considered as the main cause of global warming. So, decrease of CO2 emitted by large industrial combustion sources or power plants, is an important scientific goal. One of the approaches is based on CO2 separation and capture from flue gas, followed by sequestration in a wide range of geological formations. In this aim, CO2 is captured by sorbents like calcium oxide (CaO) in multi-cycle process of carbonation/de-carbonation. However, it was shown that the most important limitations of such process are related to the reversibility of reaction. CaO rapidly loses activity towards CO2, so the maximum extent of carbonation decreases as long as the number of cycles increases. In order to well understand the processes and parameters influencing the capture capacity of CaO-based sorbents, it appears important to get details on the kinetic law governing the reaction, which have not been really studied up to now. To investigate this reaction, CaO carbonation kinetics was followed by means of thermogravimetric analysis (TGA) on divided materials. Special care was given to the validation of the usual kinetic assumptions such as steady state and rate-determining step assumptions. The aim was to obtain a model describing the reaction in order to explain the influence of intensive variables such as carbonation temperature and CO2 partial pressure. TGA curves obtained under isothermal and isobaric conditions showed an induction period linked to the nucleation process and a strong slowing down of the reaction rate once a given fractional conversion was reached. Both phenomena were observed to depend on carbonation temperature and CO2 partial pressure. To explain these results, the evolution of texture and microstructure of the solid during the reaction was regarded as essential. Reaction at the grain scale induces a volume increase from CaO to CaCO3 which causes a change in the porosity

  13. Direct chemical reduction of neptunium oxide to neptunium metal using calcium and calcium chloride

    Science.gov (United States)

    Squires, Leah N.; Lessing, Paul

    2016-04-01

    A process of direct reduction of neptunium oxide to neptunium metal using calcium metal as the reducing agent is discussed. After reduction of the oxide to metal, the metal is separated by density from the other components of the reaction mixture and can be easily removed upon cooling. The direct reduction technique consistently produces high purity (98%-99% pure) neptunium metal.

  14. Catalytic oxidation of calcium sulfite in solution/aqueous slurry

    Institute of Scientific and Technical Information of China (English)

    WU Xiao-qin; WU Zhong-biao; WANG Da-hui

    2004-01-01

    Forced oxidation of calcium sulfite aqueous slurry is a key step for the calcium-based flue gas desulfurization(FGD) residue. Experiments were conducted in a semi-batch system and a continuous flow system on lab scales. The main reactor in semi-batch system is a 1000 ml volume flask. It has five necks for continuous feeding of gas and a batch of calcium sulfite solution/aqueous slurry. In continuous flow system, the main part is a jacketed Pyrex glass reactor in which gas and solution/aqueous slurry are fed continuously. Calcium sulfite oxidation is a series of complex free-radical reactions. According to experimental results and literature data, the reactions are influenced significantly by manganese as catalyst. At low concentration of manganese and calcium sulfite, the reaction rate is dependent on 1.5 order of sulfite concentration, 0.5 order of manganese concentration, and zero order of oxygen concentration in which the oxidation is controlled by chemical kinetics. With concentrations of calcium sulfite and manganese increasing, the reactions are independent gradually on the constituents in solution but are impacted by oxygen concentration. Manganese can accelerate the free-radical reactions, and then enhances the mass transfer of oxygen from gas to liquid. The critical concentration of calcium sulfite is 0.007 mol/L, manganese is 10-4 mol/L, and oxygen is of 0.2-0.4 atm.

  15. Sulfhydryl oxidation overrides Mg(2+) inhibition of calcium-induced calcium release in skeletal muscle triads.

    OpenAIRE

    Donoso, P; Aracena, P; Hidalgo, C.

    2000-01-01

    We studied the effect of oxidation of sulfhydryl (SH) residues on the inhibition by Mg(2+) of calcium-induced calcium release (CICR) in triad-enriched sarcoplasmic reticulum vesicles isolated from rabbit skeletal muscle. Vesicles were either passively or actively loaded with calcium before eliciting CICR by dilution at pCa 4.6-4.4 in the presence of 1.2 mM free [ATP] and variable free [Mg(2+)]. Native triads exhibited a significant inhibition of CICR by Mg(2+), with a K(0.5) approximately 50 ...

  16. Carbon Dioxide Captured from Flue Gas by Modified Ca-based Sorbents in Fixed-bed Reactor at High Temperature

    Institute of Scientific and Technical Information of China (English)

    YANG Lei; YU Hongbing; WANG Shengqiang; WANG Haowen; ZHOU Qibin

    2013-01-01

    Four kinds of Ca-based sorbents were prepared by calcination and hydration reactions using different precursors: calcium hydroxide,calcium carbonate,calcium acetate monohydrate and calcium oxide.The CO2 absorption capacity of those sorbents was investigated in a fixed-bed reactor in the temperature range of 350 650 ℃.It was found that all of those sorbents showed higher capacity for CO2 absorption when the operating temperature higher than 450 ℃.The CaAc2-CaO sorbent showed the highest CO2 absorption capacity of 299 mg·g-1.The morphology of those sorbents was examined by scanning electron microscope(SEM),and the changes of composition before and after carbonation were also determined by X-ray diffraction(XRD).Results indicated that those sorbents have the similar chemical compositions and crystalline phases before carbonation reaction [mainly Ca(OH)2],and CaCO3 is the main component after carbonation reaction.The SEM morphology shows clearly that the sorbent pores were filled with reaction products after carbonation reaction,and became much denser than before.The N2 adsorption-desorption isotherms indicated that the CaAc2-CaO and CaCO3-CaO sorbents have higher specific surface area,larger pore volume and appropriate pore size distribution than that of CaO-CaO and Ca(OH)2-CaO.

  17. Sorbents for mercury removal from flue gas

    Energy Technology Data Exchange (ETDEWEB)

    Granite, Evan J.; Hargis, Richard A.; Pennline, Henry W.

    1998-01-01

    A review of the various promoters and sorbents examined for the removal of mercury from flue gas is presented. Commercial sorbent processes are described along with the chemistry of the various sorbent-mercury interactions. Novel sorbents for removing mercury from flue gas are suggested. Since activated carbons are expensive, alternate sorbents and/or improved activated carbons are needed. Because of their lower cost, sorbent development work can focus on base metal oxides and halides. Additionally, the long-term sequestration of the mercury on the sorbent needs to be addressed. Contacting methods between the flue gas and the sorbent also merit investigation.

  18. Analysis and design of a calcium-based sulfur sorbent for applications in integrated gasification combined cycle energy systems

    Science.gov (United States)

    Hasler, David Johann Ludwig

    The reactivity of various Ca-based sorbent materials in pelletized form with H2S or CO2 was investigated at high temperatures (750--880°C). An extensive study was conducted to compare the performance of sorbent pellets derived from plaster of Paris and limestone. Multicycle absorption and regeneration tests showed that plaster-based pellets out performed the limestone-based pellets primarily due to a higher surface area and mesoporosity. The effect of pore-modifiers on the reactivity of limestone with H 2S was investigated by incorporating additives such as cornstarch, graphite and polyvinylalcohol (PVA) in the sorbent. Multicycle sulfidation and regeneration tests of the modified sorbent showed that starch did not improve the reactivity of the limestone, graphite reduced the reactivity, while PVA improved it. The effect of the chemical additives MgO and SrO on the performance of CaO-based sorbent pellets was investigated. The effect of MgO was tested by starting with materials that contained MgCO3 in a natural form, such as dolomite. The effect of SrO was tested by starting with SrCO 3 either co-precipitated with CaCO3 or by wet-mixing SrCO 3 with limestone in slurry form. The MgO was found to improve the thermal stability of the CaO-based sorbent but lowered the overall absorption capacity of the material when reacted with CO2 or H2S, while SrO decreased the thermal stability of the sorbent when it was reacted with CO2; no absorption tests were run with H2S. A study of the performance of pelletized CaO-based cores coated with a refractory material such as alumina and limestone or alumina and kaolin was conducted. The reactivity of the core and shell pellets with H2S was determined. The strength and durability of the pellets were determined by using crushing strength analysis and abrasion resistance tests. Pellets coated with either alumina and limestone or alumina and kaolin proved to be strong and adequate for use in industrial reactors. A semi

  19. Graphene Oxide - manganese(IV) Oxide Nanostructure Composite as a Photocatalytic Destructive Sorbent

    Czech Academy of Sciences Publication Activity Database

    Tolasz, Jakub; Schelonka, Darina; Slušná, Michaela; Šťastný, Martin; Kormunda, M.; Štengl, Václav

    Jeju Island, 2015. [International Conference on Photochemistry /27./. 28.06.2015-03.07.2015, Jeju Island] R&D Projects: GA MŠk(CZ) ED3.1.00/14.0328 Institutional support: RVO:61388980 Keywords : Graphene Oxide Subject RIV: CA - Inorganic Chemistry

  20. The calcium oxide influence on formation of manganese, calcium pyrovanadate solid solutions

    International Nuclear Information System (INIS)

    The X-ray graphic, derivatographic, microscopic and chemical methods are used to study solid solutions of manganese, calcium pyrovanadates containing 1-10 mass% CaO and the products of interaction of reprocessing charges of vanadium-containing converter slags intended for he formation of manganese and calcium pyrovanadates with additions of calcium oxide within 10-90 mass%. It is established that in the case of 1-6 mass% CaO content in manganese pyrovanadate solid interstitial solutions appear, while at 6-20 mass% CaO - solid substitution solutions form. The results of calculating elementary cell parameters as well as melting temperatures and pyrovanadate solid solution solubility depending on CaO content are presented. The best solubility of introduction solid solutions during vanadium extraction according to the lime technology is found

  1. Graphene oxide - manganese(IV) oxide nanostructure composite as destructive sorbent

    Czech Academy of Sciences Publication Activity Database

    Tolasz, Jakub; Schelonka, Darina; Slušná, Michaela; Šťastný, Martin; Kormunda, M.; Štengl, Václav

    Aveiro : University of Aveiro, 2015. s. 31. [International conference on Advanced Nanomaterials /6./, International conference on Graphene Technology /1./, International conference on Hydrogen Energy /1./ - ANM2015. 20.07.2015-22.07.2015, Aveiro] R&D Projects: GA MŠk(CZ) ED3.1.00/14.0328 Institutional support: RVO:61388980 Keywords : Graphene oxide Subject RIV: CA - Inorganic Chemistry http://www.anm2015.com/wp-content/uploads/2015/07/GT-abstract-Book-Final.pdf

  2. Aerogel sorbents

    Energy Technology Data Exchange (ETDEWEB)

    Begag, Redouane; Rhine, Wendell E; Dong, Wenting

    2016-04-05

    The current invention describes methods and compositions of various sorbents based on aerogels of various silanes and their use as sorbent for carbon dioxide. Methods further provide for optimizing the compositions to increase the stability of the sorbents for prolonged use as carbon dioxide capture matrices.

  3. Oxidative Stress and Maxi Calcium-Activated Potassium (BK Channels

    Directory of Open Access Journals (Sweden)

    Anton Hermann

    2015-08-01

    Full Text Available All cells contain ion channels in their outer (plasma and inner (organelle membranes. Ion channels, similar to other proteins, are targets of oxidative impact, which modulates ion fluxes across membranes. Subsequently, these ion currents affect electrical excitability, such as action potential discharge (in neurons, muscle, and receptor cells, alteration of the membrane resting potential, synaptic transmission, hormone secretion, muscle contraction or coordination of the cell cycle. In this chapter we summarize effects of oxidative stress and redox mechanisms on some ion channels, in particular on maxi calcium-activated potassium (BK channels which play an outstanding role in a plethora of physiological and pathophysiological functions in almost all cells and tissues. We first elaborate on some general features of ion channel structure and function and then summarize effects of oxidative alterations of ion channels and their functional consequences.

  4. Development of Superior Sorbents for Separation of CO2 from Flue Gas at a Wide Temperature Range During Coal Combustion

    Energy Technology Data Exchange (ETDEWEB)

    Panagiotis G. Smirniotis

    2007-06-30

    In chapter 1, the studies focused on the development of novel sorbents for reducing the carbon dioxide emissions at high temperatures. Our studies focused on cesium doped CaO sorbents with respect to other major flue gas compounds in a wide temperature range. The thermo-gravimetric analysis of sorbents with loadings of CaO doped on 20 wt% cesium demonstrated high CO{sub 2} sorption uptakes (up to 66 wt% CO{sub 2}/sorbent). It is remarkable to note that zero adsorption affinity for N{sub 2}, O{sub 2}, H{sub 2}O and NO at temperatures as high as 600 C was observed. For water vapor and nitrogen oxide we observed a positive effect for CO{sub 2} adsorption. In the presence of steam, the CO{sub 2} adsorption increased to the highest adsorption capacity of 77 wt% CO{sub 2}/sorbent. In the presence of nitrogen oxide, the final CO{sub 2} uptake remained same, but the rate of adsorption was higher at the initial stages (10%) than the case where no nitrogen oxide was fed. In chapter 2, Ca(NO{sub 3}){sub 2} {center_dot} 4H{sub 2}O, CaO, Ca(OH){sub 2}, CaCO{sub 3}, and Ca(CH{sub 3}COO){sub 2} {center_dot} H{sub 2}O were used as precursors for synthesis of CaO sorbents on this work. The sorbents prepared from calcium acetate (CaAc{sub 2}-CaO) resulted in the best uptake characteristics for CO{sub 2}. It possessed higher BET surface area and higher pore volume than the other sorbents. According to SEM images, this sorbent shows 'fluffy' structure, which probably contributes to its high surface area and pore volume. When temperatures were between 550 and 800 C, this sorbent could be carbonated almost completely. Moreover, the carbonation progressed dominantly at the initial short period. Under numerous adsorption-desorption cycles, the CaAc{sub 2}-CaO demonstrated the best reversibility, even under the existence of 10 vol % water vapor. In a 27 cyclic running, the sorbent sustained fairly high carbonation conversion of 62%. Pore size distributions indicate that their

  5. Analytical Performances of Nanostructured Gold Supported on Metal Oxide Sorbents for the Determination of Gaseous Mercury

    OpenAIRE

    Julien Lusilao-Makiese; Emmanuel Tessier; David Amouroux; Ewa Cukrowska

    2014-01-01

    Nanostructured gold supported TiO2, ZnO, and Al2O3 materials (1% w/w Au) were tested as sorbents for gaseous mercury (Hg) trapping and preconcentration. Their analytical performances were first compared with the one of traditional gold wool trap for the quantification of Hg standards injected into the argon flow followed by thermal desorption at 600°C and CVAFS detection. Good linearity and reproducibility were obtained, especially for Au/TiO2 material (R 2 = 0.995; slope: 1.39) in the volume...

  6. Dithizone-modified graphene oxide nano-sheet as a sorbent for pre-concentration and determination of cadmium and lead ions in food.

    Science.gov (United States)

    Moghadam Zadeh, Hamid Reza; Ahmadvand, Parvaneh; Behbahani, Ali; Amini, Mostafa M; Sayar, Omid

    2015-01-01

    Graphene oxide nano-sheet was modified with dithizone as a novel sorbent for selective pre-concentration and determination of Cd(II) and Pb(II) in food. The sorbent was characterised by various analytical methods and the effective parameters for Cd(II) and Pb(II) adsorption were optimised during this work. The high adsorption capacity and selectivity of this sorbent makes the method capable of fast determinations of the Cd(II) and Pb(II) content in complicated matrices even at μg l(-1) levels using commonly available instrumentation. The precision of this method was method was applied to the determination of Cd(II) and Pb(II) ions in common food samples and satisfactory results were obtained. PMID:26179656

  7. Biodiesel from sunflower oil in supercritical methanol with calcium oxide

    International Nuclear Information System (INIS)

    In this study, sunflower seed oil was subjected to the transesterification reaction with calcium oxide (CaO) in supercritical methanol for obtaining biodiesel. Methanol is used most frequently as the alcohol in the transesterification process. Calcium oxide (CaO) can considerably improve the transesterification reaction of sunflower seed oil in supercritical methanol. The variables affecting the methyl ester yield during the transesterification reaction, such as the catalyst content, reaction temperature and the molar ratio of soybean oil to alcohol, were investigated and compared with those of non-catalyst runs. The catalytic transesterification ability of CaO is quite weak under ambient temperature. At a temperature of 335 K, the yield of methyl ester is only about 5% in 3 h. When CaO was added from 1.0% to 3.0%, the transesterification speed increased evidently, while when the catalyst content was further enhanced to 5%, the yield of methyl ester slowly reached to a plateau. It was observed that increasing the reaction temperature had a favorable influence on the methyl ester yield. In addition, for molar ratios ranging from 1 to 41, as the higher molar ratios of methanol to oil were charged, the greater transesterification speed was obtained. When the temperature was increased to 525 K, the transesterification reaction was essentially completed within 6 min with 3 wt% CaO and 41:1 methanol/oil molar ratio

  8. Effect of cetyl trimethyl ammonium bromide concentration on structure, morphology and carbon dioxide adsorption capacity of calcium hydroxide based sorbents

    Science.gov (United States)

    Hlaing, Nwe Ni; Vignesh, K.; Sreekantan, Srimala; Pung, Swee-Yong; Hinode, Hirofumi; Kurniawan, Winarto; Othman, Radzali; Thant, Aye Aye; Mohamed, Abdul Rahman; Salim, Chris

    2016-02-01

    Calcium hydroxide (Ca(OH)2) has been proposed as an important material for industrial, architectural, and environmental applications. In this study, calcium acetate was used as a precursor and cetyl trimethyl ammonium bromide (CTAB) was used as a surfactant to synthesize Ca(OH)2 based adsorbents for carbon dioxide (CO2) capture. The effect of CTAB concentration (0.2-0.8 M) on the structure, morphology and CO2 adsorption performance of Ca(OH)2 was studied in detail. The synthesized samples were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FESEM), BET surfaced area and thermogravimetry-differential thermal analysis (TG-DTA) techniques. The phase purity, crystallite size, Brunauer-Emmett-Teller (BET) surface area and CO2 adsorption performance of Ca(OH)2 precursor adsorbents were significantly increased when the concentration of CTAB was increased. XRD results showed that pure Ca(OH)2 phase was obtained at the CTAB concentration of 0.8 M. TGA results exhibited that 0.8 M of CTAB-assisted Ca(OH)2 precursor adsorbent possessed a residual carbonation conversion of ∼56% after 10 cycles.

  9. Magnetic graphene oxide-polystyrene and magnetic activated carbon-polystyrene nanocomposites as sorbents for bisphenol A.

    Science.gov (United States)

    Rekos, Kyriazis; Kampouraki, Zoi Christina; Samanidou, Victoria; Deliyanni, Eleni

    2016-04-01

    Magnetic graphene oxide-polystyrene and magnetic activated carbon-polystyrene nanocomposites as sorbents for bisphenol A. Kyriazis Rekos1, Zoi Christina Kampouraki1, Victoria Samanidou2, Eleni Deliyanni1 1 Laboratory of General and Inorganic Chemical Technology, Department of Chemistry, Aristotle University of Thessaloniki, GR-541 24 Thessaloniki, Greece 2 Laboratory of Analytical Chemistry, Department of Chemistry, Aristotle University of Thessaloniki, GR-541 24 Thessaloniki, Greece The aim of this work was to prepare and characterize novel composites of magnetic activated carbon or magnetic graphene oxide with polystyrene (GO/PSm), through one step simple and effective route. Μagnetite nanoparticles, prepared in the laboratory, were dispersed in the presence of activated carbon (C) or graphene oxide (GO) in a polystyrene (PS) solution in dimethylformamide, at elevated temperature, for the fabrication of the magnetite-Carbon-PS (C-PSm) and magnetite- Graphene Oxide-PS (GO-PSm) hybrid-nanoparticles. For comparison, C-PS and GO-PS composites were also prepared in the same route. The nanocomposites were tested for their sorption ability for an endocrine disruptor, bisphenol A. The effect of solution pH, initial concentration, contact time and temperature were examined. The magnetic graphite oxide-polystyrene presented higher adsorption capacity (100 mg/g) than the non magnetic composites (70 mg/g), as well as than initial graphite oxide (20 mg/g). FTIR, XRD, BET, TGA, VSM and SEM were performed in order to investigate the role of the PS on the better adsorption performance of the mGO-PS nanocomposites. The characterization with these techniques revealed the possible interactions of the surface functional groups of activated carbon and/or graphite oxide with polystyrene that resulted in the better performance of the magnetic nanocomposites for bisphenol A adsorption.

  10. New type of sorbents based on polyethers and some hydrophobic anions Pt. 2

    International Nuclear Information System (INIS)

    The preparation of sorbents composed of polyethylene glycol and metal(II) salts of heteropolyacids has been described. It has been found that the calcium salt of phosphomolybdic acid of the type Ca3(PMo12O40)2 is precipitated in the presence of polyethylene glycol (m.wt. 1000). In this precipitate one calcium cation combines approximately with 10.9 ethylene oxide units of polyethylene glycol. The solubility of the sorbents has been found to be several tenths of a gram per litre of water or 0.1M hydrochloric acid. The sorption of radium has been studied as a function of the composition of the sorbents. High distribution ratios (Ksub(D) approximately 103-104) have been reached using 0.1M hydrochloric acid solution. (author)

  11. A Novel Synthesis Method of Porous Calcium Silicate Hydrate Based on the Calcium Oxide/Polyethylene Glycol Composites

    OpenAIRE

    Wei Guan; Fangying Ji; Yong Cheng; Zhuoyao Fang; Dexin Fang; Peng Yan; Qingkong Chen

    2013-01-01

    This paper proposed a novel method to prepare porous calcium silicate hydrate (CSH) based on the calcium oxide/polyethylene glycol (CaO/PEG2000) composites as the calcium materials. The porosity formation mechanism was revealed via X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), Brunauer-Emmett-Teller (BET), and Fourier transformed infrared spectroscopy (FT-IR). The reactivity of silica materials (SiO2) enhanced by increasing pH value. Ca2+ could not sustain rele...

  12. Use of calcium oxide in palm oil methyl ester production

    Directory of Open Access Journals (Sweden)

    Kulchanat Prasertsit

    2014-04-01

    Full Text Available Introducing an untreated calcium oxide (CaO as a solid heterogeneous catalyst for biodiesel production from palm oil by transesterification was studied in this work. The four studied parameters were methanol to oil molar ratio, CaO catalyst concentration, reaction time, and water content. The results for palm oil show that when the water content is higher than 3%wt and the amount of CaO greater than 7%wt soap formation from saponification occurs. A higher methanol to oil molar ratio requires a higher amount of CaO catalyst to provide the higher product purity. The appropriate methanol to CaO catalyst ratio is about 1.56. Commercial grade CaO gives almost the same results as AR grade CaO. In addition, reusing commercial grade CaO for about 5 to 10 repetitions without catalyst regeneration drops the percentage of methyl ester purity approximately 5 to 10%, respectively.

  13. Phosphate Adsorption using Modified Iron Oxide-based Sorbents in Lake Water: Kinetics, Equilibrium, and Column Tests

    Science.gov (United States)

    Adsorption behavior of Bayoxide ® E33 (E33) and three E33-modified sorbents for the removal of phosphate from lake water was investigated in this study. E33-modified sorbents were synthesized by coating with manganese (E33/Mn) and silver (E33/AgI and E33/AgII) nanoparticles. Adso...

  14. Selection of metal oxides in the preparation of rice husk ash (RHA)/CaO sorbent for simultaneous SO{sub 2} and NO removal

    Energy Technology Data Exchange (ETDEWEB)

    Dahlan, Irvan; Lee, Keat Teong; Kamaruddin, Azlina Harun [School of Chemical Engineering, Universiti Sains Malaysia, Engineering Campus, Seri Ampangan, 14300 Nibong Tebal, Pulau Pinang (Malaysia); Mohamed, Abdul Rahman, E-mail: chrahman@eng.usm.my [School of Chemical Engineering, Universiti Sains Malaysia, Engineering Campus, Seri Ampangan, 14300 Nibong Tebal, Pulau Pinang (Malaysia)

    2009-07-30

    In this work, the removal of SO{sub 2} and NO from simulated flue gas from combustion process was investigated in a fixed-bed reactor using rice husk ash (RHA)/CaO-based sorbent. Various metal precursors were used in order to select the best metal impregnated over RHA/CaO sorbents. The results showed that RHA/CaO sorbents impregnated with CeO{sub 2} had the highest sorption capacity among other impregnated metal oxides for the simultaneous removal of SO{sub 2} and NO. Infrared spectroscopic results indicated the formation of both sulfate (SO{sub 4}{sup 2-}) and nitrate (NO{sub 3}{sup -}) species due to the catalytic role played by CeO{sub 2}. Apart from that, the catalytic activity of the RHA/CaO/CeO{sub 2} sorbent was found to be closely related to its physical properties (specific surface area, total pore volume and average pore diameter).

  15. Gas desulfurization macrokinetics in the calcium oxide reaction

    International Nuclear Information System (INIS)

    High amounts of sulfur dioxide (SO2) are produced by burning of fossil fuels in air in excess, a pollutant agent which, once reaching the atmosphere, transforms in sulfuric acid . One solution of diminishing the SO2 releases is injection of powder limestone in the oven. The reaction CaCO3 = CaO + CO2 gives rise to porous calcium oxide grains which react with SO2 in the presence of oxygen. As a result, calcium sulphate is formed by the reaction CaO + SO2 + 1/2O2 = CaSO4. This technology is convenient for thermal power plants due to small investments and simple operation. However,the desulfurization degree is reduced and the process kinetics is still unelucidated. In this work, the kinetics of the second reaction is studied by thermogravimetry with CAHN TG-121 device. Conversion-time kinetic diagrams were generated for five granulometric classes of Ca CO3 with an average diameter of 25-900 μm. The measurements were carried out at 973 K - 1173 K and gas flow speeds of 0.023 - 0.0277 m/s. The kinetic parameters of the external mass transfer, solid crust diffusion and chemical reaction were determined. The influence of external mass transfer in all operation conditions is insignificant. The influence of solid crust diffusion is dominant even for the smallest particles (25 μm). Therefore, the process is described by a combined macrokinetics reaction-diffusion model, where the resistance to the diffusion is about 80% of the total resistance. Complementary structure determinations using structural models are required for the solid undergoing the reaction in order to rigorously identify the enhancing factors of the process. (authors)

  16. Effect of Calcium Oxide Microstructure on the Diffusion of Isotopes

    CERN Document Server

    Fernandes Ramos, João Pedro; Stora, T

    2012-01-01

    Calcium oxide (CaO) powder targets have been successfully used at CERN-ISOLDE to produce neutron deficient exotic argon and carbon isotopes under proton irradiation at high temperatures (>1000°C). These targets outperform the other related targets for the production of the same beams. However, they presented either slow release rates (yields) from the beginning or a rapid decrease over time. This problem was believed to come from the target microstructure degradation, justifying the material investigation. In order to do so, the synthesis, reactivity in ambient air and sintering kinetics of CaO were studied, through surface area determination by N2 adsorption, X-ray diffraction for crystalline phase identification and crystallite size determination, and scanning and transmission electron microscopy to investigate the microstructure. The synthesis studies revealed that a nanometric material is obtained from the decarbonation of CaCO3 in vacuum at temperatures higher than 550°C, which is very reactive in air....

  17. Manganese Oxide Nanoarchitectures as Broad-Spectrum Sorbents for Toxic Gases.

    Science.gov (United States)

    Long, Jeffrey W; Wallace, Jean M; Peterson, Gregory W; Huynh, Kim

    2016-01-20

    We demonstrate that sol-gel-derived manganese oxide (MnOx) nanoarchitectures exhibit broad-spectrum filtration activity for three chemically diverse toxic gases: NH3, SO2, and H2S. Manganese oxides are synthesized via the reaction of NaMnO4 and fumaric acid to form monolithic gels of disordered, mixed-valent Na-MnOx; incorporated Na(+) is readily exchanged for H(+) by subsequent acid rinsing to form a more crystalline H-MnOx phase. For both Na-MnOx and H-MnOx forms, controlled pore-fluid removal yields either densified, yet still mesoporous, xerogels or low-density aerogels (prepared by drying from supercritical CO2). The performance of these MnOx nanoarchitectures as filtration media is assessed using dynamic-challenge microbreakthrough protocols. We observe technologically relevant sorption capacities under both dry conditions and wet (80% relative humidity) for each of the three toxic industrial chemicals investigated. The Na-MnOx xerogels and aerogels provide optimal performance with the aerogel exhibiting maximum sorption capacities of 39, 200, and 680 mg g(-1) for NH3, SO2, and H2S, respectively. Postbreakthrough characterization using X-ray photoelectron spectroscopy (XPS) and diffuse-reflectance infrared Fourier transform spectroscopy (DRIFTS) confirms that NH3 is captured and partially protonated within the MnOx structure, while SO2 undergoes oxidation by the redox-active oxide to form adsorbed sulfate at the MnOx surface. Hydrogen sulfide is also oxidized to form a combination of sulfate and sulfur/polysulfide products, concomitant with a decrease in the average Mn oxidation state from 3.43 to 2.94 and generation of a MnOOH phase. PMID:26741498

  18. Conductivity study of nitrogen-doped calcium zinc oxide prepared by spray pyrolysis

    Science.gov (United States)

    Hsu, Yu-Ting; Lan, Wen-How; Huang, Kai-Feng; Lin, Jia-Ching; Chang, Kuo-Jen

    2016-01-01

    In this study, the spray pyrolysis method was used to prepare unintentionally doped and nitrogen-doped calcium zinc oxide films by using zinc acetate, calcium nitrate precursor, and ammonium acetate precursor. Morphological and structural analyses were conducted using scanning electron microscopy and X-ray diffraction. The results indicated that film grain size decreased as the nitrogen doping was increased. Both calcium oxide and zinc oxide structures were identified in the unintentionally doped calcium zinc oxide. When nitrogen doping was introduced, the film mainly exhibited a zinc oxide structure with preferred (002) and (101) orientations. The concentration and mobility were investigated using a Hall measurement system. P-type films with a mobility and concentration of 10.6 cm2 V-1 s-1 and 2.8×1017 cm-3, respectively, were obtained. Moreover, according to a temperature-dependent conductivity analysis, an acceptor state with activation energy 0.266 eV dominated the p-type conduction for the unintentionally doped calcium zinc oxide. By contrast, a grain boundary with a barrier height of 0.274-0.292 eV dominated the hole conduction for the nitrogen-doped calcium zinc oxide films.

  19. Deuterium oxide normalizes blood pressure and vascular calcium uptake in Dahl salt-sensitive hypertensive rats

    International Nuclear Information System (INIS)

    This study examined the effect of 25% deuterium oxide in drinking water on systolic blood pressure, uptakes of calcium, and rubidium 86 by aortas of Dahl salt-sensitive rats on 0.4% (low) and 8% (high) sodium chloride (salt) diet. Twenty-four rats were divided into four groups. Groups I and II were on the low salt diet and groups III and IV on the high salt diet from 6 weeks of age. Additionally, at 10 weeks of age groups I and III were placed on 100% water and groups II and IV on 25% deuterium oxide. At 14 weeks, systolic blood pressure, uptakes of calcium, and rubidium 86 by aortas were significantly higher (p less than 0.01) in rats on the high salt diet as compared with those on the low salt diet. Deuterium oxide intake normalized systolic blood pressure and aortic calcium uptake but not aortic rubidium 86 uptake in hypertensive rats on the high salt diet. Deuterium oxide had no effect on blood pressure or aortic calcium uptake in rats on the low salt diet. The parallel increase in systolic blood pressure and vascular calcium uptake suggests that increased calcium uptake mechanisms are associated with hypertension in salt-sensitive Dahl rats. Furthermore, deuterium oxide appears to normalize elevated blood pressure in salt-sensitive hypertensive rats by normalizing elevated vascular (aortic) calcium uptake

  20. Comparison of Calcium Phosphate and Zinc Oxide Nanoparticles as Dermal Penetration Enhancers for Albumin

    OpenAIRE

    Shokri, Narges; Javar, H. A.

    2015-01-01

    Dermal drug delivery is highly preferred by patients due to its several advantages. Protein therapeutics have attracted huge attention recently. Since dermal delivery of proteins encounter problems, in this investigation, zinc oxide nanoparticles and calcium phosphate nanoparticles were compared as enhancers for dermal permeation of albumin. Albumin was applied simultaneously with zinc oxide nanoparticles or calcium phosphate nanoparticles on pieces of mouse skin. Skin permeation of albumin o...

  1. Nanotubes from Oxide-Based Misfit Family: The Case of Calcium Cobalt Oxide.

    Science.gov (United States)

    Panchakarla, Leela S; Lajaunie, Luc; Ramasubramaniam, Ashwin; Arenal, Raul; Tenne, Reshef

    2016-06-28

    Misfit layered compounds (MLCs) have generated significant interest in recent years as potential thermoelectric materials. MLC nanotubes could reveal behavior that is entirely different from the bulk material. Recently, new chemical strategies were exploited for the synthesis of nanotubular forms of chalcogenide-based MLCs, which are promising candidates for thermoelectric materials. However, analogous synthesis of oxide-based MLC nanotubes has not been demonstrated until now. Here, we report a chemical strategy for synthesis of cobalt-oxide-based misfit nanotubes. A combination of high-resolution (scanning) transmission electron microscopy (including image simulations), spatially resolved electron energy-loss spectroscopy, electron diffraction, and density functional theory (DFT) calculations is used to discover the formation of a phase within these nanotubes that differs significantly from bulk calcium cobaltite MLCs. Furthermore, DFT calculations show that this phase is semiconducting with a band gap in excess of 1 eV, unlike bulk calcium cobaltite MLCs, which are known to be metallic. Through systematic experiments, we propose a formation mechanism for these nanotubes that could also apply more generally to realizing other oxide-based MLC nanotubes. PMID:27215812

  2. A Novel Synthesis Method of Porous Calcium Silicate Hydrate Based on the Calcium Oxide/Polyethylene Glycol Composites

    Directory of Open Access Journals (Sweden)

    Wei Guan

    2013-01-01

    Full Text Available This paper proposed a novel method to prepare porous calcium silicate hydrate (CSH based on the calcium oxide/polyethylene glycol (CaO/PEG2000 composites as the calcium materials. The porosity formation mechanism was revealed via X-ray diffraction (XRD, field-emission scanning electron microscopy (FESEM, Brunauer-Emmett-Teller (BET, and Fourier transformed infrared spectroscopy (FT-IR. The reactivity of silica materials (SiO2 enhanced by increasing pH value. Ca2+ could not sustain release from CaO/PEG2000 and reacted with caused by silica to form CSH until the hydrothermal temperature reached to 170°C, avoiding the hardly dissolved intermediates formation efficiently. The as-prepared CSH, due to the large specific surface areas, exhibited excellent release capability of Ca2+ and OH−. This porous CSH has potential application in reducing the negative environmental effects of continual natural phosphate resource depletion.

  3. Hydrogen peroxide-mediated oxidative stress disrupts calcium binding on calmodulin: More evidence for oxidative stress in vitiligo

    International Nuclear Information System (INIS)

    Patients with acute vitiligo have low epidermal catalase expression/activities and accumulate 10-3 M H2O2. One consequence of this severe oxidative stress is an altered calcium homeostasis in epidermal keratinocytes and melanocytes. Here, we show decreased epidermal calmodulin expression in acute vitiligo. Since 10-3M H2O2 oxidises methionine and tryptophan residues in proteins, we examined calcium binding to calmodulin in the presence and absence of H2O2 utilising 45calcium. The results showed that all four calcium atoms exchanged per molecule of calmodulin. Since oxidised calmodulin looses its ability to activate calcium ATPase, enzyme activities were followed in full skin biopsies from lesional skin of patients with acute vitiligo (n = 6) and healthy controls (n = 6). The results yielded a 4-fold decrease of ATPase activities in the patients. Computer simulation of native and oxidised calmodulin confirmed the loss of all four calcium ions from their specific EF-hand domains. Taken together H2O2-mediated oxidation affects calcium binding in calmodulin leading to perturbed calcium homeostasis and perturbed L-phenylalanine-uptake in the epidermis of acute vitiligo

  4. Calcium Oxide Supported on Monoclinic Zirconia as a Highly Active Solid Base Catalyst

    NARCIS (Netherlands)

    Frey, A.M.; Haasterecht, van T.; Jong, de K.P.; Bitter, J.H.

    2013-01-01

    Calcium oxide supported on ZrO2 is a highly active catalyst for base-catalyzed reactions such as aldol-type reactions and transesterification reactions. The role of key parameters during preparation, that is, impregnation versus precipitation, heat treatment, and metal oxide loading on the basicity

  5. Bioactive calcium phosphate coating formed on micro-arc oxidized magnesium by chemical deposition

    Energy Technology Data Exchange (ETDEWEB)

    Liu, G.Y. [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Hu, J., E-mail: hujin@hit.edu.cn [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Ding, Z.K.; Wang, C. [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China)

    2011-01-01

    In order to improve the bioactivity of the micro-arc oxidized magnesium, a calcium phosphate coating was formed on the surface of micro-arc oxidized magnesium using a chemical method. The microstructures of the substrate and the calcium phosphate coating before and after the simulated body fluids (SBF) incubation were characterized by X-ray diffraction, Fourier-transformed infrared spectroscopy and scanning electron microscopy. The results showed that the calcified coating was composed of calcium deficient hydroxyapatite (HA) and dicalcium phosphate dihydrate (DCPD). After SBF incubation, some new apatite formation on the calcified coating surface from SBF could be found. The corrosion behaviours of the samples in SBF were also investigated by potentiodynamic polarization curves and immersion tests. The results showed that calcium phosphate coating increased the corrosion potential, and decreased the hydrogen gas release.

  6. Solidification of aqueous tritium-containing wastes with calcium oxide and asphalt

    International Nuclear Information System (INIS)

    A simple method is proposed for solidifying aqueous tritium-containing wastes with calcium oxide and asphalt. We incorporated tritiated calcium hydroxide into molten asphalt at 100-210/degree/C and studied the evolution of tritium (T) oxides there from as well as the extent to which calcium and tritium are leached out of the solidified product. Depending on temperature and heating time, the evolution of HTO from a Ca(OH)OT-asphalt mixture was low (between 5.6 x 10/sup /minus/4/ and 5.9 x 10/sup /minus/4/ wt.% of the original amount). Tritium evolution rates and leaching coefficients of tritium and calcium showed the solidified product to have high stability in water. Conclusions were drawn as to the usefulness of the proposed method

  7. Oxidant-Induced Inhibition of Myocardial Calcium-Independent Phospholipase A2

    OpenAIRE

    McHowat, Jane; Swift, Luther M.; Sarvazyan, Narine

    2001-01-01

    We discovered the acute inhibition of myocardial phospholipase A2 activity by micromolar concentrations of tert-butyl hydroperoxide and hydrogen peroxide. Specifically, freshly isolated adult rat cardiomyocytes were treated with the oxidants for 30 min, and phospholipase A2 activity was assessed in cell subcellular fractions using (16:0, [3H]18:1) plasmenylcholine and phosphatidylcholine substrates in the absence or presence of calcium. Calcium-independent phospholipase A2 activity was inhibi...

  8. Sorbent preparation/modification/additives. Final report, September 1, 1992--November 30, 1993

    Energy Technology Data Exchange (ETDEWEB)

    Prudich, M.E.; Venkataramakrishnan, R. [Ohio Univ., Athens, OH (United States)

    1994-02-01

    Sorbent preparation techniques used today have generally been adapted from techniques traditionally used by the lime industry. Traditional dry hydration and slaking processes have been optimized to produce materials intended for use in the building industry. These preparation techniques should be examined with an eye to optimization of properties important to the SO{sub 2} capture process. The study of calcium-based sorbents for sulfur dioxide capture is complicated by two factors: (1) little is known about the chemical mechanisms by which the standard sorbent preparation and enhancement techniques work, and (2) a sorbent preparation technique that produces a calcium-based sorbent that enjoys enhanced calcium utilization in one regime of operation [flame zone (>2400 F), in-furnace (1600--2400 F), economizer (800--1100 F), after air preheater (<350 F)] may not produce a sorbent that enjoys enhanced calcium utilization in the other reaction zones. Again, an in-depth understanding of the mechanism of sorbent enhancement is necessary if a systematic approach to sorbent development is to be used. As a long-term goal, an experimental program is being carried out for the purpose of (1) defining the effects of slaking conditions on the properties of calcium-based sorbents, (2) determining how the parent limestone properties of calcium-based sorbents, and (3) elucidating the mechanism(s) relating to the activity of various dry sorbent additives. An appendix contains a one-dimensional duct injection model with modifications to handle the sodium additives.

  9. Nano-thick calcium oxide armed titanium: boosts bone cells against methicillin-resistant Staphylococcus aureus

    Science.gov (United States)

    Cao, Huiliang; Qin, Hui; Zhao, Yaochao; Jin, Guodong; Lu, Tao; Meng, Fanhao; Zhang, Xianlong; Liu, Xuanyong

    2016-02-01

    Since the use of systemic antibiotics for preventing acute biomaterial-associated infections (BAIs) may build up bacterial resistance and result in huge medical costs and unpredictable mortality, new precaution strategies are required. Here, it demonstrated that titanium armed with a nano-thick calcium oxide layer was effective on averting methicillin-resistant Staphylococcus aureus (MRSA) infections in rabbits. The calcium oxide layer was constructed by, firstly, injecting of metallic calcium into titanium via a plasma immersion ion implantation process, and then transforming the outer most surface into oxide by exposing to the atmosphere. Although the calcium oxide armed titanium had a relative low reduction rate (~74%) in growth of MRSA in vitro, it could markedly promote the osteogenic differentiation of bone marrow stem cells (BMSCs), restore local bone integration against the challenge of MRSA, and decrease the incidence of MRSA infection with a rate of 100% (compared to the titanium control). This study demonstrated for the first time that calcium, as one of the major elements in a human body, could be engineered to avert MRSA infections, which is promising as a safe precaution of disinfection for implantable biomedical devices.

  10. Thermodynamics of HCl and HF Interferences in Hot Producer Gas Desulfurization by Zinc, Cerium and Lanthanum Oxide Based Sorbents

    Czech Academy of Sciences Publication Activity Database

    Svoboda, Karel; Hartman, Miloslav; Havlica, Jaromír; Leitner, J.; Pohořelý, Michael; Šyc, Michal; Chen, P.-Ch.

    - : -, 2015 - (ScienceKNOW Conferences C.B.), s. 202 ISBN 978-84-944311-1-1. [International Conference on Chemical and Biochemical Engineering. Paris-Saint Denis (FR), 20.07.2015-22.07.2015] Grant ostatní: NSC(TW) 103-2923-E-042A-001-MY3 Institutional support: RVO:67985858 Keywords : gas cleaning * thermodynamics * Ce2O3, La2O3 sorbent Subject RIV: CI - Industrial Chemistry, Chemical Engineering

  11. Nacre-like calcium carbonate controlled by ionic liquid/graphene oxide composite template

    International Nuclear Information System (INIS)

    Nacre-like calcium carbonate nanostructures have been mediated by an ionic liquid (IL)-graphene oxide (GO) composite template. The resultant crystals were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy, and X-ray powder diffractometry (XRD). The results showed that either 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM]BF4) or graphene oxide can act as a soft template for calcium carbonate formation with unusual morphologies. Based on the time-dependent morphology changes of calcium carbonate particles, it is concluded that nacre-like calcium carbonate nanostructures can be formed gradually utilizing [BMIM]BF4/GO composite template. During the process of calcium carbonate formation, [BMIM]BF4 acted not only as solvents but also as morphology templates for the fabrication of calcium carbonate materials with nacre-like morphology. Based on the observations, the possible mechanisms were also discussed. - Highlights: • Nacre-like CaCO3/GO were prepared by gas diffusion. • Ionic liquid/GO served as composite templates. • The interaction of Ca2+ ions and GO played a very important role in the formation of nacre-like CaCO3

  12. Biodiesel production using calcium manganese oxide as catalyst and different raw materials

    International Nuclear Information System (INIS)

    Highlights: ► Biodiesel production using a calcium manganese oxide catalyst was studied. ► The active specie was Ca0.9Mn0.1O and its deactivation occurred by hydration. ► The studied catalyst presented lower activation temperature than CaO. ► Biodiesel production and quality using different raw materials is reported. ► Compared to the conventional process, biodiesel water content improved. - Abstract: The use of heterogeneous catalysts for biodiesel production aims to simplify the production process as well as to reduce purification costs and related environmental impacts. Calcium manganese oxide was recently identified by the authors as an interesting heterogeneous catalyst for biodiesel production from animal fat; however, the difference between this and other catalysts, the catalyst activation/deactivation mechanisms, its behaviour in the synthesis using different raw materials as well as the impacts of its use on product quality remained unclear. Therefore, the present work: (i) compared biodiesel production using calcium manganese oxide and other catalysts (CaO and NaOH); (ii) studied the reasons leading to activation/deactivation of the heterogeneous catalyst; (iii) analysed biodiesel heterogeneous synthesis using calcium manganese oxide and different raw materials (lard, waste frying oil and a mixture); and (iv) evaluated raw material and catalyst impact on the product quality. Considering the use of different catalysts, the results showed that, after 8 h of reaction, product purity was similar using the different catalysts, being 92.5 wt.% using both NaOH and calcium manganese oxide and 93.8 wt.% using CaO. The active species of the heterogeneous catalysts were CaO, in the case of calcinated calcium carbonate, and Ca0.9Mn0.1O, in the case of calcinated calcium manganese oxide. Because the deactivating species were different for both catalysts, the calcium manganese oxide required lower activation temperature, which should be an advantage. When

  13. Purifications of calcium carbonate and molybdenum oxide powders for neutrinoless double beta decay experiment, AMoRE

    International Nuclear Information System (INIS)

    The AMoRE (Advanced Mo based Rare process Experiment) collaboration is going to use calcium molybdate crystals to search for neutrinoless double beta decay of 100Mo isotope. In order to make the crystal, we use calcium carbonate and molybdenum oxide powders as raw materials. Therefore it is highly necessary to reduce potential sources for radioactive backgrounds such as U and Th in the powders. In this talk, we will present our studies for purification of calcium carbonate and molybdenum oxide powders

  14. Dispersive solid phase microextraction with magnetic graphene oxide as the sorbent for separation and preconcentration of ultra-trace amounts of gold ions.

    Science.gov (United States)

    Kazemi, Elahe; Dadfarnia, Shayessteh; Haji Shabani, Ali Mohammad

    2015-08-15

    A selective, simple and rapid dispersive solid phase microextraction was developed using magnetic graphene oxide (MGO) as an efficient sorbent for the separation and preconcentration of gold ions. The MGO was synthesized by means of the simple one step chemical coprecipitation method, characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM). Gold ions retained by the sorbent were eluted using 0.5mol L(-)(1) thiourea in 0.1mol L(-1) HCl solution and determined by the flow injection flame atomic absorption spectrometry (FI-FAAS). The factors affecting the separation and preconcentration of gold were investigated and optimized. Under the optimized conditions, the method exhibited a linear dynamic range of 0.02-100.0µg L(-)(1) with a detection limit of 4ng L(-1) and an enrichment factor of 500. The relative standard deviations of 3.2% and 4.7% (n=6) were obtained at 20µg L(-1) level of gold ions for the intra and the inter day analysis, respectively. The method was successfully applied to the determination of gold ions in water and waste water samples as well as a certified reference material (CCU-1b, copper flotation concentrate). PMID:25966414

  15. Concentration dependent effect of calcium on brain mitochondrial bioenergetics and oxidative stress parameters

    Directory of Open Access Journals (Sweden)

    Patrick G Sullivan

    2013-12-01

    Full Text Available Mitochondrial dysfunction following traumatic brain and spinal cord injury (TBI and SCI plays a pivotal role in the development of secondary pathophysiology and subsequent neuronal cell death. Previously, we demonstrated a loss of mitochondrial bioenergetics in the first 24 h following TBI and SCI initiates a rapid and extensive necrotic event at the primary site of injury. Within the mitochondrial derived mechanisms, the cross talk and imbalance amongst the processes of excitotoxicity, Ca2+ cycling/overload, ATP synthesis, free radical production, and oxidative stress damage ultimately leading to mitochondrial damage followed by neuronal cell death and loss of behaviors. Mitochondria are one of the most important organelles that regulate for intracellular calcium (Ca2+ homeostasis; and are equipped with a tightly regulated Ca2+ transport system. However, owing to the lack of consensus and the link between the downstream effects of calcium in published literature, we undertook a systematic in vitro study for measuring concentration dependent effects of calcium (100-1000 nmols/mg mitochondrial protein on mitochondrial respiration, enzyme activities, reactive oxygen/nitrogen species (ROS/RNS generation, membrane potential (∆Ψ and oxidative damage markers in isolated brain mitochondria. We observed a dose- and time-dependent inhibition of mitochondrial respiration by calcium without influencing mitochondrial pyruvate dehydrogenase complex (PDHC and NADH dehydrogenase (Complex I enzyme activities. We observed dose-dependent decreased production of hydrogen peroxide and total ROS/RNS species generation by calcium and no significant changes in protein and lipid oxidative damage markers. These results may shed new light on the prevailing dogma of the direct effects of calcium on mitochondrial bioenergetics, free radical production and oxidative stress parameters that are primary regulatory mitochondrial mechanisms following neuronal injury.

  16. Preparation and bioactivity of micro-arc oxidized calcium phosphate coatings

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Y.K. [Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Ji' nan, Shandong 250061 (China); School of Materials Science and Engineering, Shandong University, Ji' nan, Shandong 250061 (China); Chen, C.Z., E-mail: czchen@sdu.edu.cn [Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Ji' nan, Shandong 250061 (China); School of Materials Science and Engineering, Shandong University, Ji' nan, Shandong 250061 (China); Wang, D.G.; Lin, Z.Q. [Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Ji' nan, Shandong 250061 (China); School of Materials Science and Engineering, Shandong University, Ji' nan, Shandong 250061 (China)

    2013-09-16

    Calcium phosphate (CaP) coatings were prepared on ZK60 magnesium alloy by micro-arc oxidation (MAO) in electrolyte containing calcium acetate monohydrate (CH{sub 3}COO){sub 2}Ca·H{sub 2}O) and disodium hydrogen phosphate dodecahydrate (Na{sub 2}HPO{sub 4}·12H{sub 2}O). Scanning electron microscope (SEM), energy-dispersive X-ray spectrometry (EDX) and X-ray diffractometer (XRD) were employed to characterize the microstructure, elemental distribution and phase composition of the CaP coatings respectively. Simulated body fluid (SBF) immersion test was used to evaluate the coating degradability and bioactivity. After 30 days of SBF immersion, the CaP coatings effectively reduce the degradation rate. The surfaces of CaP coatings are covered by a new layer formed of numerous needle-like, spherical and columned calcium phosphates. SEM, EDX and XRD results suggest that these calcium phosphates are bioactive calcium phosphate phases such as hydroxyapatite (Ca{sub 10}(PO{sub 4}){sub 6}(OH){sub 2}, HA) and calcium pyrophosphates (Ca{sub 2}P{sub 2}O{sub 7}, CPP). The formation of these calcium phosphates indicates that the CaP coatings have bioactivity. - Highlights: • Bioactive CaP coatings are successfully formed on ZK60 magnesium alloy. • CaP coatings consist of MgO, MgF{sub 2}, CaO, CaF{sub 2} and Ca{sub 3}(PO{sub 4}){sub 2}. • Needle-like, spherical and columned calcium phosphates formed in SBF. • CaP coatings exhibit bioactivity and low corrosion rate.

  17. Electrophoretic deposition of calcium silicate-reduced graphene oxide composites on titanium substrate

    DEFF Research Database (Denmark)

    Mehrali, Mehdi; Akhiani, Amir Reza; Talebian, Sepehr;

    2016-01-01

    silicate-reduced graphene oxide (CS-rGO) composites were synthesized, using an in situ hydrothermal method. CS nanowires were uniformly decorated on the rGO, with an appropriate interfacial bonding. The CS-rGO composites behaved like hybrid composites when deposited on a titanium substrate by cathodic......Calcium silicate (CS)/graphene coatings have been used to improve the biological and mechanical fixation of metallic prosthesis. Among the extraordinary features of graphene is its very high mechanical strength, which makes it an attractive nanoreinforcement material for composites. Calcium...

  18. Serum calcium response following oral zinc oxide administrations in dairy cows

    DEFF Research Database (Denmark)

    Thilsing-Hansen, T; Jørgensen, R J; Thilsing, Trine

    2001-01-01

    lactating cows dropped dramatically indicating the existence of an antagonistic effect between Zn and Ca. The first Zn induced hypocalcaemic episode in the lactating cows was followed by a rise in serum calcium to a level above the pre-dosing level and above the mean value of the control group. The depth of...... the hypocalcaemic response decreased with the number of zinc oxide dosings. This effect was explained as a response from the stimulation of the calcium homeostatic mechanisms. In the Zn dosed non-lactating cows responses were similar but less clear. The perspective of these findings is discussed in...

  19. KINETICS OF HOT-GAS DESULFURIZATION SORBENTS FOR TRANSPORT REACTORS

    Energy Technology Data Exchange (ETDEWEB)

    K.C. Kwon

    2002-01-01

    Hot-gas desulfurization for the integrated gasification combined cycle (IGCC) process has been investigated by many researchers to remove effectively hydrogen sulfide with various metal oxide sorbents at elevated temperatures. Various metal oxide sorbents are formulated with metal oxides such as Fe, Co, Zn, and Ti. Initial reaction kinetics of formulated sorbents with hydrogen sulfide is studied in the presence of various amounts of moisture and hydrogen at various reaction temperatures. The objectives of this research are to study initial reaction kinetics for a sorbent-hydrogen sulfide heterogeneous reaction system, to investigate effects of concentrations of hydrogen sulfide, hydrogen, and moisture on dynamic absorption of H{sub 2}S into sorbents, and to evaluate effects of temperature and sorbent amounts on dynamic absorption of H{sub 2}S into sorbents. Experimental data on initial reaction kinetics of hydrogen sulfide with metal oxide sorbents were obtained with a 0.83-cm{sup 3} differential reactor. The reactivity of MCRH-67 was examined in this report. This sorbent was obtained from the Research Triangle Institute (RTI). The sorbent in the form of 130 mm particles are reacted with 18000-ppm hydrogen sulfide at 350-525 C. The range of space time of reaction gas mixtures is 0.069-0.088 s. The range of reaction duration is 4-180 s.

  20. Intercellular calcium signaling and nitric oxide feedback during constriction of rabbit renal afferent arterioles

    DEFF Research Database (Denmark)

    Uhrenholt, Torben Rene; Schjerning, J; Vanhoutte, Paul M. G.;

    2007-01-01

    Vasoconstriction and increase in the intracellular calcium concentration ([Ca(2+)](i)) of vascular smooth muscle cells may cause an increase of endothelial cell [Ca(2+)](i), which, in turn, augments nitric oxide (NO) production and inhibits smooth muscle cell contraction. This hypothesis was tested...... in microperfused rabbit renal afferent arterioles, using fluorescence imaging microscopy with the calcium-sensitive dye fura-2 and the NO-sensitive dye 4-amino-5-methylamino-2',7'-difluorescein. Both dyes were loaded into smooth muscle and endothelium. Depolarization with 100 mmol/l KCl led to a...... transient vasoconstriction which was converted into a sustained response by N-nitro-l-arginine methyl ester (l-NAME). Depolarization increased smooth muscle cell [Ca(2+)](i) from 162 +/- 15 nmol/l to a peak of 555 +/- 70 nmol/l (n = 7), and this response was inhibited by 80% by the l-type calcium channel...

  1. Development of kinetic model for the reaction between SO{sub 2}/NO and coal fly ash/CaO/CaSO{sub 4} sorbent

    Energy Technology Data Exchange (ETDEWEB)

    Keat-Teong Lee; Kok-Chong Tan; Irvan Dahlan; Abdul Rahman Mohamed [Universiti Sains Malaysia, Pulau Pinang (Malaysia)

    2008-08-15

    Sorbents for semidry-type flue gas desulfurization (FGD) process can be synthesized by mixing coal fly ash, calcium oxide, and calcium sulfate in a hydration process. As sorbent reactivity is directly correlated with the specific surface area of the sorbent, reacting temperature, concentration of the reacting gas species and relative humidity, two major aim in the development of a kinetic model for the FGD process are to obtain an accurate model and at the same time, incorporating all the parameters above. Thus, the objective of this work is to achieve these two aims. The kinetic model proposed is based on the material balance for the gaseous and solid phase using partial differential equations incorporating a modified surface coverage model which assumes that the reaction is controlled by chemical reaction on sorbent grain surface. The kinetic parameters of the mathematical model were obtained from a series of experimental desulfurization reactions carried out under isothermal conditions at various operating parameters; inlet concentration of SO{sub 2}, inlet concentration of NO, reaction temperature and relative humidity. For a variety of initial operating conditions, the mathematical model is shown to give comparable predictive capability when used for interpolation and extrapolation with error less than 7%. The model was found useful to predict the daily operation of flue gas desulfurization processes by using CaO/CaSO{sub 4}/coal fly ash sorbent to remove SO{sub 2} from flue gas. 22 refs., 4 figs.

  2. Characterization of calcium containing plasma electrolytic oxidation coatings on AM50 magnesium alloy

    International Nuclear Information System (INIS)

    An attempt was made to produce calcium containing plasma electrolytic oxidation (PEO) coatings on AM50 magnesium alloy using an alkaline electrolyte. This study was performed in three alkaline electrolytes containing calcium hydroxide and sodium phosphate with three different mass ratios viz., 1:2.5, 1:5 and 1:7.5. All the three coatings produced were found to contain Ca and P in appreciable amounts. The concentration of P was found to be higher in the coatings obtained in the electrolytes with higher concentration of phosphate ions. Even though all the three coatings were found to be constituted with magnesium oxide and magnesium phosphate phases, X-ray diffraction analyses revealed that the phase composition was influenced by the phosphate ion concentration/conductivity of the electrolyte. Further, the PEO coating obtained in the 1:7.5 ratio electrolyte was found to contain di-calcium phosphate (monetite) and calcium peroxide phases, which were absent in the other two coatings. Potentiodynamic polarization studies performed in 0.1 M NaCl solution showed that the coatings obtained from the 1:5 ratio electrolyte possessed a superior corrosion resistance, which is attributed to the combined effect of thickness, compactness and phase/chemical composition of this coating.

  3. Effect of oral drenching with zinc oxide or synthetic zeolite A on total blood calcium in dairy cows

    DEFF Research Database (Denmark)

    Jørgensen, R J; Hansen, T; Jensen, M L;

    2001-01-01

    values. Oral drenching with a single dose of zinc oxide of 100 mg/kg of body weight as well as with zeolite in doses of 500 g of zeolite/cow twice a day for 2.5 d was reflected in serum calcium levels. In the group given zeolite A, there was a depression in evening values of total serum calcium although...

  4. Analysis of the color alteration and radiopacity promoted by bismuth oxide in calcium silicate cement

    Directory of Open Access Journals (Sweden)

    Marina Angelica Marciano

    2013-07-01

    Full Text Available The aim of the study was to determine if the increase in radiopacity provided by bismuth oxide is related to the color alteration of calcium silicate-based cement. Calcium silicate cement (CSC was mixed with 0%, 15%, 20%, 30% and 50% of bismuth oxide (BO, determined by weight. Mineral trioxide aggregate (MTA was the control group. The radiopacity test was performed according to ISO 6876/2001. The color was evaluated using the CIE system. The assessments were performed after 24 hours, 7 and 30 days of setting time, using a spectrophotometer to obtain the ΔE, Δa, Δb and ΔL values. The statistical analyses were performed using the Kruskal-Wallis/Dunn and ANOVA/Tukey tests (p 3 mm equivalent of Al. The MTA group was statistically similar to the CSC / 30% BO group (p > 0.05. In regard to color, the increase of bismuth oxide resulted in a decrease in the ΔE value of the calcium silicate cement. The CSC group presented statistically higher ΔE values than the CSC / 50% BO group (p < 0.05. The comparison between 24 hours and 7 days showed higher ΔE for the MTA group, with statistical differences for the CSC / 15% BO and CSC / 50% BO groups (p < 0.05. After 30 days, CSC showed statistically higher ΔE values than CSC / 30% BO and CSC / 50% BO (p < 0.05. In conclusion, the increase in radiopacity provided by bismuth oxide has no relation to the color alteration of calcium silicate-based cements.

  5. Phase formation and chemical phase equilibria in aqueous-based systems pertinent to waste-management: calcium oxide-alluminum oxide-borate-water, calcium oxide-lead oxide-phosphate-water and calcium oxide-arsenate-water

    Science.gov (United States)

    Bothe, James Vincent, Jr.

    This thesis explores three aqueous-based systems that have importance in the area of waste-management: (1) CaO-Alsb2Osb3-Bsb2Osb3-Hsb2O, (2) CaO-PbO-Psb2Osb5-Hsb2O and (3) CaO-Assb2Osb5-Hsb2O. More specifically, the objective of this research is to identify various precipitated compounds that can effectively immobilize certain elements that either directly or indirectly have an adverse effect on the environment. In the first quaternary system, CaO-Alsb2Osb3-Bsb2Osb3-Hsb2O, boron is the element desired to be ``fixed'' because ``free'' boron is the cause of delayed hardening in cement paste intended for the encapsulation of nuclear waste. Soluble boron also causes the cement paste to prematurely set, a phenomenon called ``flash-set.'' Isothermal calorimetry was used to track the progress of tricalcium aluminate hydration in the presence of boric acid and Ca(OH)sb2 and revealed the presence of a pronounced induction period, the length of which varied with both temperature and boric acid concentration. It was determined that a diffusion barrier, most likely an amorphous calcium borate, deposited onto the active anhydrous tricalcium aluminate grains inhibiting further hydration. Also, under certain conditions, the precipitation of crystalline 4CaO{*}Alsb2Osb3{*}1/2Bsb2Osb3{*}12Hsb2O may be responsible for the observed flash-set due to its flat, plate-like morphology. Another quaternary hydrate, 6CaO{*}Alsb2Osb3{*}2Bsb2Osb3{*}39Hsb2O (boro-ettringite) was also synthesized during this research and crystallized as hexagonal prisms. In contrast to the fast crystallization of 4CaO{*}Alsb2Osb3{*}1/2Bsb2Osb3{*}12Hsb2O, boro-ettringite was observed to form slowly and in stages with the precipitation of the transient phase CaO-Bsb2Osb3{*}6Hsb2O preceding it. Further investigation of these two hydrates lead to the construction of a quaternary phase diagram and to the determination of their solubility products (pKsp = -logKsp), which were determined to be 44.23 for boro

  6. Bulk and Grain Boundary Electrical Behaviours in Nb and Sn Doped Calcium Copper Titanium Oxide

    OpenAIRE

    Arbintarso, Ellyawan Setyo

    2014-01-01

    Three types of Calcium Copper Titanium oxide (CCTO), i.e. pure CCTO, niobium doped CCTO, and tin doped CCTO were obtained by mixed oxide route. The niobium and tin as a dopant were selected with the variation of doping concentration to create the stoichiometric formula CaCu3Ti4-xMxO12 (x = 0.05, 0.10, 0.15, 0.20, and 0.25; M = Nb, and Sn). Three different sintering times were applied for all the samples. X-ray diffraction, scanning electron microscopy,impedance spectroscopy at high and low te...

  7. Asenapine modulates nitric oxide release and calcium movements in cardiomyoblasts

    Directory of Open Access Journals (Sweden)

    Elena Grossini

    2016-01-01

    Full Text Available Objective: To examine the effects of asenapine on nitric oxide (NO release and Ca2+ transients in H9C2 cell line, which were either subjected to peroxidation or not. Materials and Methods: H9C2 were treated with asenapine alone or in presence of intracellular kinase blockers, serotoninergic and dopaminergic antagonists, and voltage Ca2+ channels inhibitors. Experiments were also performed in H9C2 treated with hydrogen peroxide. NO release and intracellular Ca2+ were measured through specific probes. Results: In H9C2, asenapine differently modulated NO release and Ca2+ movements depending on peroxidative condition. The Ca2+ pool mobilized by asenapine mainly originated from the extracellular space and was slightly affected by thapsigargin. Moreover, the effects of asenapine were reduced or prevented by kinases blockers, dopaminergic and serotoninergic receptors inhibitors, and voltage Ca2+ channels blockers.Conclusions: On the basis of our findings, we can conclude that asenapine by interacting with its specific receptors, exerts dual effects on NO release and Ca2+ homeostasis in H9C2; this would be of particular clinical relevance when considering their role in cardiac function modulation.

  8. Ultra-trace determination of arsenic species in environmental waters, food and biological samples using a modified aluminum oxide nanoparticle sorbent and AAS detection after multivariate optimization

    International Nuclear Information System (INIS)

    We describe a simple and efficient method for solid phase extraction and speciation of trace quantities of arsenic. It is based on the use of functionalized aluminum oxide nanoparticles and does not require any oxidation or reduction steps. The experimental parameters affecting extraction and quantitation were optimized using fractional factorial design methods. Adsorbed arsenic was eluted from the sorbent with 1 M hydrochloric acid and determined by graphite furnace atomic absorption spectrometry. Preconcentration factors up to 750 were achieved depending on the sample volume. Studies on potential interferences by various anions and cations showed the method to be highly selective. Under optimum conditions, the calibration plots are linear in the 5.0 to 280 ng L−1 and 8.0 to 260 ng L−1 concentration ranges for As(III) and total arsenic, respectively. The detection limits (calculated for S/N ratios of 3) are 1.81 and 1.97 ng L−1 for As(III) and total arsenic, respectively. The method was successfully applied to the determination and speciation of arsenic in (spiked) environmental, food and biological samples and gave good recoveries. The method was validated using a certified geological reference material. (author)

  9. High calcium diet improves the liver oxidative stress and microsteatosis in adult obese rats that were overfed during lactation.

    Science.gov (United States)

    Conceição, E P S; Moura, E G; Soares, P N; Ai, X X; Figueiredo, M S; Oliveira, E; Lisboa, P C

    2016-06-01

    Obesity is related to diabetes, higher oxidative stress and nonalcoholic fatty liver disease, and dietetic therapies, for instance calcium-rich diet, can improve these dysfunctions. Rats raised in small litters (SL) had increased fat depots and insulin resistance at adulthood associated with higher liver oxidative stress and microsteatosis. Thus, we evaluated if dietary calcium can improve these changes. In PN3, litter size was adjusted to 3 pups (SL group) to induce overfeeding, while controls had 10 pups until weaning. At PN120, SL group was randomly divided into: rats fed with standard chow or fed with calcium supplementation (SL-Ca group, 10 g/kg chow) for 60 days. At PN180, dietary calcium normalized food consumption, visceral fat, plasma aspartate aminotransferase (AST) and glycaemia. Concerning oxidative balance, calcium restored both higher hepatic lipid peroxidation and protein carbonylation as well as higher plasma lipid peroxidation. Higher fatty acid synthase (FAS) content, steatosis and lower protein kinase B (Akt) in SL group were normalized by dietary calcium and SL-Ca rats had lower hepatic cholesterol. Thus, calcium supplementation improved the insulin sensitivity, redox balance and steatosis in the liver. Therefore, dietary calcium can be a promising therapy for liver disease in the metabolic syndrome. PMID:27108106

  10. Styrene epoxidation with hydrogen peroxide over calcium oxide catalysts prepared from various precursors

    Institute of Scientific and Technical Information of China (English)

    Qingming Gu; Dan Han; Lei Shi; Qi Sun

    2012-01-01

    A series of CaO samples were prepared by calcination of commercially available and synthesis of calcium salt precursors such as calcium acetate,carbonate,hydroxide and oxalate etc.CaO samples were found to be effective for the epoxidation of styrene using hydrogen peroxide as an oxidant in the presence of acetonitrile.To determine the influence of the physicochemical properties and surface basicity on the catalytic activity,the prepared CaO samples were characterized using thermogravimetry (TG),X-ray diffraction (XRD),scanning electron microscopy (SEM),N2-adsorption and temperature-programmed desorption of CO2 (CO2-TPD).The results indicate that the amounts of very strong basic sites and high basicity strength on CaO sample are key factors for its excellent catalytic performance.In contrast,the surface area,porosity and the surface structure of CaO sample have a relatively minor effect on the catalytic activity.CaO sample,obtained by the decomposition of Ca(OH)2,prepared by precipitating calcium nitrate with sodium hydroxide in ethylene glycol solution,exhibits the highest amount of very strong basic sites and stronger strength of basic sites,and therefore it catalyses the epoxidation of styrene with the highest rate among the tested CaO samples.Under the selected reaction conditions,the selectivity of 97.5% to styrene oxide at a conversion in excess of 99% could be obtained.

  11. Calcium-sensing receptor regulates stomatal closure through hydrogen peroxide and nitric oxide in response to extracellular calcium in Arabidopsis

    OpenAIRE

    Wang, Wen-Hua; Yi, Xiao-Qian; Han, Ai-Dong; Liu, Ting-Wu; Chen, Juan; Wu, Fei-Hua; Dong, Xue-Jun; He, Jun-Xian; Pei, Zhen-Ming; Zheng, Hai-Lei

    2011-01-01

    The Arabidopsis calcium-sensing receptor CAS is a crucial regulator of extracellular calcium-induced stomatal closure. Free cytosolic Ca2+ (Ca2+ i) increases in response to a high extracellular calcium (Ca2+ o) level through a CAS signalling pathway and finally leads to stomatal closure. Multidisciplinary approaches including histochemical, pharmacological, fluorescent, electrochemical, and molecular biological methods were used to discuss the relationship of hydrogen peroxide (H2O2) and nitr...

  12. Effect of calcium oxide on the efficiency of ferrous ion oxidation and total iron precipitation during ferrous ion oxidation in simulated acid mine drainage treatment with inoculation of Acidithiobacillus ferrooxidans.

    Science.gov (United States)

    Liu, Fenwu; Zhou, Jun; Jin, Tongjun; Zhang, Shasha; Liu, Lanlan

    2016-01-01

    Calcium oxide was added into ferrous ion oxidation system in the presence of Acidithiobacillus ferrooxidans at concentrations of 0-4.00 g/L. The pH, ferrous ion oxidation efficiency, total iron precipitation efficiency, and phase of the solid minerals harvested from different treatments were investigated during the ferrous ion oxidation process. In control check (CK) system, pH of the solution decreased from 2.81 to 2.25 when ferrous ions achieved complete oxidation after 72 h of Acidithiobacillus ferrooxidans incubation without the addition of calcium oxide, and total iron precipitation efficiency reached 20.2%. Efficiency of ferrous ion oxidation and total iron precipitation was significantly improved when the amount of calcium oxide added was ≤1.33 g/L, and the minerals harvested from systems were mainly a mixture of jarosite and schwertmannite. For example, the ferrous ion oxidation efficiency reached 100% at 60 h and total iron precipitation efficiency was increased to 32.1% at 72 h when 1.33 g/L of calcium oxide was added. However, ferrous ion oxidation and total iron precipitation for jarosite and schwertmannite formation were inhibited if the amount of calcium oxide added was above 2.67 g/L, and large amounts of calcium sulfate dihydrate were generated in systems. PMID:27003087

  13. Immobilization of calcium oxide solid reactant on a yttria fabric and thermodynamic analysis of UT-3 thermochemical hydrogen production cycle

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Man Su [Mechanical and Aerospace Engineering, University of Florida, P.O. Box 116300, Gainesville, FL 32611 (United States); Goswami, D. Yogi; Stefanakos, Elias K. [Clean Energy Research Center, University of South Florida, 4202 E Fowler Avenue Tampa, FL 33620 (United States)

    2009-01-15

    UT-3 cycle has been considered as one of the most promising thermochemical processes for hydrogen production. In order to make the cycle practical, however, the solid reactants in the cyclic reactions must have adequate lifespan and better kinetics. In this paper, hydrolysis reaction of calcium bromide, the slowest process in the cycle, was investigated theoretically and experimentally. A new type of calcium oxide reactant was fabricated by dispersing and fixing it on a yttria fabric via a comparatively straightforward and inexpensive immobilization process. The characteristics and cyclic performance of the prepared fabric samples were evaluated and compared with the conventional calcium oxide pellets. It was shown that the calcium oxide immobilized on the yttria fabric had continuous higher reactivity and comparable hydrolysis rate compared with the conventional calcium oxide pellets. A theoretical analysis of the thermodynamic cycle was also conducted. The effect of excess steam on the equilibrium conversion was significant; however, the reaction temperature was limited due to the melting point of calcium bromide. By continuously removing the product gas, the conversion in the hydrolysis reaction which is the slowest reaction in the cycle could be completed theoretically. This hypothesis was found to be true based on the experimental tests. (author)

  14. Enhanced durability and reactivity for zinc ferrite desulfurization sorbent

    Energy Technology Data Exchange (ETDEWEB)

    Silaban, A.; Harrison, D.P. (Louisiana State Univ., Baton Rouge, LA (United States). Dept. of Chemical Engineering)

    1989-05-02

    AMAX Research Development Center (AMAX R D) has been investigating methods for enhancing the reactivity and durability of the zinc ferrite desulfurization sorbent. Zinc ferrite sorbents are intended for use in desulfurization of hot coal gas in integrated gasification combined cycle (IGCC) or molten carbonate fuel cell (MCFC) applications. For the present program, the reactivity of the sorbent may be defined as its sulfur sorption capacity at the breakthrough point and at saturation in a bench-scale, fixed-bed reactor. Durability may be defined as the ability of the sorbent to maintain important physical characteristics such as size, strength, and specific surface area during 10 cycles of sulfidation and oxidation.

  15. 40 CFR 721.10018 - Calcium hydroxide oxide silicate (Ca6(OH)2O2(Si2O5)3).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Calcium hydroxide oxide silicate (Ca6... New Uses for Specific Chemical Substances § 721.10018 Calcium hydroxide oxide silicate (Ca6(OH)2O2... substance identified as calcium hydroxide oxide silicate (Ca6(OH)2O2(Si2O5)3) (PMN P-01-442; CAS No....

  16. Evaluation of Physical and Structural Properties of Biofield Energy Treated Barium Calcium Tungsten Oxide

    OpenAIRE

    Trivedi, Mahendra Kumar

    2015-01-01

    Barium calcium tungsten oxide (Ba2CaWO6) is known for its double perovskite-type crystal structure. The present study was designed to see the effect of biofield energy treatment on physical, atomic, and structural properties of Ba2CaWO6. In this study, Ba2CaWO6 powder sample was divided into two parts, one part was remained as untreated, denoted as control, while the other part was subjected to Mr. Trivedi’s biofield energy treatment and coded as treated. After that, the control and tre...

  17. Chemical composition and dry matter digestibility of sugar cane oxide treated with calcium

    OpenAIRE

    C.O. Romão; G.G.P. Carvalho; V.M. Leite; Santos, A. S.; D.M.T. Chagas; O.L. Ribeiro; P.A. Oliveira; Magalhães, A F; A.J.V. Pires

    2014-01-01

    The aim of this study was to identify the most adequate level of calcium oxide (CaO) in the treatment of sugar cane by evaluating the chemical composition and in vitro digestibility of dry matter. The sugar cane was homogenized with CaO levels 0, 0.75, 1.5, 2.25, 3.0, 3.75 and 4.5%, in natura matter, for 24 hours. The dry matter and mineral matter increased, while the organic matter of the sugar cane decreased (P

  18. Diets Based on Sugar Cane Treated with Calcium Oxide for Lambs

    OpenAIRE

    G.G.P. Carvalho; R. Garcia; A.J.V. Pires; R.R. Silva; Detmann, E.; Filho, A. Eustaquio; Ribeiro, L. S. O.; L.M. Carvalho

    2013-01-01

    This experiment was conducted to evaluate the intake, nutrient apparent digestibility and the effect of total collection days (two and four days) on apparent digestibility estimates for lambs fed diets containing sugar cane treated with calcium oxide (CaO). Eight Santa Inês castrated male lambs with a 16.6±1.8 kg body weight were used. The lambs were distributed in two 4×4 Latin squares, with four experimental periods of 14 d each. The animals were kept in 1.2 m2 individual pens, and the inta...

  19. Absorption of calcium ions on oxidized graphene sheets and study its dynamic behavior by kinetic and isothermal models

    Science.gov (United States)

    Fathy, Mahmoud; Abdel Moghny, Th.; Mousa, Mahmoud Ahmed; El-Bellihi, Abdel-Hameed A.-A.; Awadallah, Ahmed E.

    2016-07-01

    Sorption of calcium ion from the hard underground water using novel oxidized graphene (GO) sheets was studied in this paper. Physicochemical properties and microstructure of graphene sheets were investigated using Raman spectrometer, thermogravimetry analyzer, transmission electron microscope, scanning electron microscope. The kinetics adsorption of calcium on graphene oxide sheets was examined using Lagergren first and second orders. The results show that the Lagergren second-order was the best-fit model that suggests the conception process of calcium ion adsorption on the Go sheets. For isothermal studies, the Langmuir and Freundlich isotherm models were used at temperatures ranging between 283 and 313 K. Thermodynamic parameters resolved at 283, 298 and 313 K indicating that the GO adsorption was exothermic spontaneous process. Finally, the graphene sheets show high partiality toward calcium particles and it will be useful in softening and treatment of hard water.

  20. Experimental study on the reuse of spent rapidly hydrated sorbent for circulating fluidized bed flue gas desulfurization.

    Science.gov (United States)

    Li, Yuan; Zheng, Kai; You, Changfu

    2011-11-01

    Rapidly hydrated sorbent, prepared by rapidly hydrating adhesive carrier particles and lime, is a highly effective sorbent for moderate temperature circulating fluidized bed flue gas desulfurization (CFB-FGD) process. The residence time of fine calcium-containing particles in CFB reactors increases by adhering on the surface of larger adhesive carrier particles, which contributes to higher sorbent calcium conversion ratio. The circulation ash of CFB boilers (α-adhesive carrier particles) and the spent sorbent (β and γ-adhesive carrier particles) were used as adhesive carrier particles for producing the rapidly hydrated sorbent. Particle physical characteristic analysis, abrasion characteristics in fluidized bed and desulfurization characteristics in TGA and CFB-FGD systems were investigated for various types of rapidly hydrated sorbent (α, β, and γ-sorbent). The adhesion ability of γ-sorbent was 50.1% higher than that of α-sorbent. The abrasion ratio of β and γ-sorbent was 16.7% lower than that of α-sorbent. The desulfurization abilities of the three sorbent in TGA were almost same. The desulfurization efficiency in the CFB-FGD system was up to 95% at the bed temperature of 750 °C for the β-sorbent. PMID:21928832

  1. Calcium-based mixed oxide catalysts for methanolysis of Jatropha curcas oil to biodiesel

    International Nuclear Information System (INIS)

    Calcium-based mixed oxides catalysts (CaMgO and CaZnO) have been investigated for the transesterification of Jatropha curcas oil (JCO) with methanol, in order to evaluate their potential as heterogeneous catalysts for biodiesel production. Both CaMgO and CaZnO catalysts were prepared by coprecipitation method of the corresponding mixed metal nitrate solution in the presence of a soluble carbonate salt at ∼ pH 8-9. The catalysts were characterized by X-ray diffraction (XRD), temperature programmed desorption of CO2 (CO2-TPD), scanning electron microscopy (SEM) and N2 adsorption (BET). The conversion of JCO by CaMgO and CaZnO were studied and compared with calcium oxide (CaO), magnesium oxide (MgO) and zinc oxide (ZnO) catalysts. Both CaMgO and CaZnO catalysts showed high activity as CaO and were easily separated from the product. CaMgO was found more active than CaZnO in the transesterification of JCO with methanol. Under the suitable transesterification conditions at 338 K (catalyst amount = 4 wt. %, methanol/oil molar ratio = 15, reaction time = 6 h), the JCO conversion of more than 80% can be achieved over CaMgO and CaZnO catalysts. Even though CaO gave the highest activity, the conversion of JCO decreased significantly after reused for forth run whereas the conversion was only slightly lowered for CaMgO and CaZnO after sixth run.

  2. Oxidative damage increases intracellular free calcium [Ca2+]i concentration in human erythrocytes incubated with lead.

    Science.gov (United States)

    Quintanar-Escorza, M A; González-Martínez, M T; del Pilar, Intriago-Ortega Ma; Calderón-Salinas, J V

    2010-08-01

    One important effect of lead toxicity in erythrocytes consists of increasing [Ca(2+)](i) which in turn may cause alterations in cell shape and volume and it is associated with cellular rigidity, hemolysis, senescence and apoptosis. In this work, we proposed the use of erythrocytes incubated with Pb(2+) to assess association of the mechanisms of lead erythrocyte oxidative damage and calcium homeostasis. Lead incubation produced an increase in [Ca(2+)](i) dose- and time-dependent, which mainly involved Ca(2+) entry mechanism. Additionally, in this in vitro model alterations similar to erythrocytes of lead-exposed workers were produced: Increase in Ca(2+) influx, decrease in (Ca(2+)-Mg(2+))-ATPase activity and GSH/GSGG ratio; increase in lipoperoxidation, protein carbonylation and osmotic fragility accompanied of dramatic morphological changes. Co-incubation with trolox, a soluble vitamin-E analog is able to prevent these alterations indicating that lead damage mechanism is strongly associated with oxidative damage with an intermediate toxic effect via [Ca(2+)](i) increase. Furthermore, erythrocytes oxidation induced with a free radical generator (APPH) showed effects in [Ca(2+)](i) and oxidative damage similar to those found in erythrocytes incubated with lead. Co-incubation with trolox prevents the oxidative effects induced by AAPH in erythrocytes. These results suggest that increase of [Ca(2+)](i) depends on the oxidative status of the erythrocytes incubated with lead. We consider that this model contributes in the understanding of the relation between oxidative damage induced by lead exposure and Ca(2+) homeostasis, the consequences related to these phenomena and the molecular basis of lead toxicity in no excitable cells. PMID:20460147

  3. Superhydrophobic and Superoleophilic Micro-Wrinkled Reduced Graphene Oxide as a Highly Portable and Recyclable Oil Sorbent.

    Science.gov (United States)

    Feng, Chunfang; Yi, Zhifeng; She, Fenghua; Gao, Weimin; Peng, Zheng; Garvey, Christopher J; Dumée, Ludovic F; Kong, Lingxue

    2016-04-20

    The potential of superhydrophobic and superoleophilic microwrinkled reduced graphene oxide (MWrGO) structures is here demonstrated for oil spill cleanup. The impact of the thickness of MWrGO films on the sorption performance of three different oils was investigated. Water contact angles across the MWrGO surfaces were found to exceed 150°, while oil could be easily absorbed by the microwrinkled structures of MWrGO within seconds after contact. Although the oil surface diffusion rate was not found to be dependent on the thickness of the graphene oxide films, the oil sorption capacity was the largest with the thinner MWrGO films due to the high surface area resulting from their fine surface texture. Furthermore, the composite films can be repeatedly used for at least 20 oil sorption-removal cycles without any notable loss in selectivity and uptake capacity. These MWrGO/elastomer composite films could be applied as a potential candidate material for future oil spill cleanup. PMID:27043421

  4. Manganese-based sorbents for coal gas desulfurization

    Energy Technology Data Exchange (ETDEWEB)

    Gasper-Galvin, L.D.; Fisher, E.P. [USDOE Morgantown Energy Technology Center, WV (United States); Goyette, W.J. [Chemetals, Inc., Baltimore, MD (United States)

    1996-12-31

    The intent of this study is to perform a preliminary screening on a particular Mn-based sorbent, CST-939 (from Chemetals), for hot gas desulfurization. The purpose of the preliminary screening is to determine which temperature and type of coal gas this sorbent demonstrates the greatest capacity and efficiency for sulfur removal. The following conclusions were made from the data collected on the CST-939 sorbent: The sorbent efficiency and capacity are much greater at 343{degrees}C (650{degrees}F) than at 871{degrees}C (1,600{degrees}F). The sorbent efficiency and capacity are much greater in the presence of the more highly-reducing Shell gas than with the less-reducing KRW gas. The sorbent showed tremendous capacity for sulfur pickup, with actual loadings as high as 21 weight percent. Oxidative regeneration at 871{degrees}C (1,600{degrees}F) appeared to decompose sulfate; however, unusually high SO{sub 2} release during the second sulfidations and/or reductive regenerations indicated incomplete regeneration. The average crush strength of the reacted sorbent did not indicate any loss of strength as compared to the fresh sorbent. Superior sorbent performance was obtained in the presence of simulated Shell gas at 538{degrees}C (1,000{degrees}F).

  5. EVALUATION OF PILOT ESP PERFORMANCE WITH ELEVATED LOADINGS FROM SORBENT INJECTION PROCESSES

    Science.gov (United States)

    The paper gives results of an evaluation of pilot electrostatic precipitator (ESP) performance with elevated loadings from the advanced silicate (ADVACATE) sorbent injection process. Measurements were made of a calcium silicate sorbent injected into a duct upstream of an ESP. he ...

  6. Influence of addition of calcium oxide on physicochemical properties of Portland cement with zirconium or niobium oxide

    Directory of Open Access Journals (Sweden)

    Mario Tanomaru-Filho

    2015-01-01

    Full Text Available Context: Calcium oxide (CaO may be added to mineral trioxide aggregate (MTA or Portland cement (PC to improve physicochemical and biological properties. Aims: To evaluate the physicochemical properties of PC associated with radiopacifiers and CaO. Materials and Methods: MTA Angelus, PC + 30% zirconium oxide (Zr, or 30% niobium oxide (Nb associated with 10 or 20% of CaO were evaluated. Gilmore needles were used to evaluate initial and final setting time. Compressive strength was evaluated after the periods of 24 hours and 21 days. pH was analyzed after 3, 12, 24 hours, 7, 14, 21 days. Solubility and flow tests were performed based on the ISO 6876. The data obtained were submitted to analysis of variance and Tukey tests (P ≤ 0.05. Results: The associations with 10% CaO showed greater strength that the associations with 20% CaO. The shortest initial setting time was observed for the association PC + Zr + 20% CaO and MTA. All the cements presented alkaline pH. The flow of all cements was similar. The highest solubility was found in the associations with 20% CaO. Conclusion: The addition of CaO to PC favored the alkaline property and the PC + Zr + 20% CaO presented setting time similar to MTA.

  7. Adsorption of superparamagnetic iron oxide nanoparticles on silica and calcium carbonate sand.

    Science.gov (United States)

    Park, Yoonjee C; Paulsen, Jeffrey; Nap, Rikkert J; Whitaker, Ragnhild D; Mathiyazhagan, Vidhya; Song, Yi-Qiao; Hürlimann, Martin; Szleifer, Igal; Wong, Joyce Y

    2014-01-28

    Superparamagnetic iron oxide (SPIO) nanoparticles have the potential to be used in the characterization of porous rock formations in oil fields as a contrast agent for NMR logging because they are small enough to traverse through nanopores and enhance contrast by shortening NMR T2 relaxation time. However, successful development and application require detailed knowledge of particle stability and mobility in reservoir rocks. Because nanoparticle adsorption to sand (SiO2) and rock (often CaCO3) affects their mobility, we investigated the thermodynamic equilibrium adsorption behavior of citric acid-coated SPIO nanoparticles (CA SPIO NPs) and poly(ethylene glycol)-grafted SPIO nanoparticles (PEG SPIO NPs) on SiO2 (silica) and CaCO3 (calcium carbonate). Adsorption behavior was determined at various pH and salt conditions via chemical analysis and NMR, and the results were compared with molecular theory predictions. Most of the NPs were recovered from silica, whereas far fewer NPs were recovered from calcium carbonate because of differences in the mineral surface properties. NP adsorption increased with increasing salt concentration: this trend was qualitatively explained by molecular theory, as was the role of the PEG grafting in preventing NPs adsorption. Quantitative disagreement between the theoretical predictions and the data was due to NP aggregation, especially at high salt concentration and in the presence of calcium carbonate. Upon aggregation, NP concentrations as determined by NMR T2 were initially overestimated and subsequently corrected using the relaxation rate 1/T2, which is a function of aggregate size and fractal dimension of the aggregate. Our experimental validation of the theoretical predictions of NP adsorption to minerals in the absence of aggregation at various pH and salt conditions demonstrates that molecular theory can be used to determine interactions between NPs and relevant reservoir surfaces. Importantly, this integrated experimental and

  8. Noscapine protects OLN-93 oligodendrocytes from ischemia-reperfusion damage: Calcium and nitric oxide involvement.

    Science.gov (United States)

    Nadjafi, S; Ebrahimi, S-A; Rahbar-Roshandel, N

    2015-12-01

    This study was carried out to evaluate the effects of noscapine, a benzylisoquinoline alkaloid from opium poppy, on oligodendrocyte during ischemia/reperfusion-induced excitotoxic injury. Changes in intracellular calcium levels due to chemical ischemia and nitric oxide (NO) production during ischemia/reperfusion were evaluated as the hallmarks of ischemia-derived excitotoxic event. OLN-93 cell line (a permanent immature rat oligodendrocyte) was used as a model of oligodendrocyte. 30- or 60-minute-oxygen-glucose deprivation/24 hours reperfusion were used to induce excitotoxicity. MTT (3-[4,5-Dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide) assay was used to evaluate cell viability. Ratiometric fluorescence microscopy using Ca(2+)-sensitive indicator Fura-2/AM was utilized to assess intracellular calcium levels. NO production was evaluated by Griess method. Noscapine (4 μM) significantly attenuated intracellular Ca(2+) elevation (P < 0.001). Also, noscapine significantly decreased NO production during a 30-minute oxygen-glucose deprivation/reperfusion (P < 0.01). The inhibitory effect of noscapine (4 μM) on intracellular Ca(2+) was greater than ionotropic glutamate receptors antagonists. Noscapine is protective against ischemia/reperfusion-induced excitotoxic injury in OLN-93 oligodendrocyte. This protective effect seems to be related to attenuation of intracellular Ca(2+) overload and NO production. PMID:26690027

  9. Polyaniline-graphene oxide nanocomposite sensor for quantification of calcium channel blocker levamlodipine.

    Science.gov (United States)

    Jain, Rajeev; Sinha, Ankita; Khan, Ab Lateef

    2016-08-01

    A novel polyaniline-graphene oxide nanocomposite (PANI/GO/GCE) sensor has been fabricated for quantification of a calcium channel blocker drug levamlodipine (LAMP). Fabricated sensor has been characterized by electrochemical impedance spectroscopy, square wave and cyclic voltammetry, Raman spectroscopy and Fourier transform infrared (FTIR) spectroscopy. The developed PANI/GO/GCE sensor has excellent analytical performance towards electrocatalytic oxidation as compared to PANI/GCE, GO/GCE and bare GCE. Under optimized experimental conditions, the fabricated sensor exhibits a linear response for LAMP for its oxidation over a concentration range from 1.25μgmL(-1) to 13.25μgmL(-1) with correlation coefficient of 0.9950 (r(2)), detection limit of 1.07ngmL(-1) and quantification limit of 3.57ngmL(-1). The sensor shows an excellent performance for detecting LAMP with reproducibility of 2.78% relative standard deviation (RSD). The proposed method has been successfully applied for LAMP determination in pharmaceutical formulation with a recovery from 99.88% to 101.75%. PMID:27157745

  10. Complete Oxidation of Methane over Palladium Supported on Alumina Modified with Calcium, Lanthanum, and Cerium Ions

    Institute of Scientific and Technical Information of China (English)

    Beata Stasinska; Wojciech Gac; Theophilos Ioannides; Andrzej Machocki

    2007-01-01

    The activity and thermal stability of Pd/Al2O3 and Pd/(Al2O3+MOx) (M=Ca, La, Ce) palladium catalysts in the reaction of complete oxidation of methane are presented in this study. The catalyst supports were prepared by sol-gel method and they were dried either conventionally or with supercritical carbon dioxide. Then they were impregnated with palladium nitrate solution. The catalysts with unmodified alumina had a high surface area. The activity and thermal stability of the alumina-supported catalyst was also very high. The introduction of calcium, lanthanum, or cerium oxide into alumina support caused a decrease of the surface area in the way dependent on the support precursor drying method. These modifiers decreased the activity of palladium catalysts, and they required higher temperatures for the complete oxidation of methane than unmodified Pd/Al2O3. The improvement of the palladium activity by lanthanum and cerium support modifier was observed only at low temperatures of the reaction.

  11. Corrosion behavior of silicon nitride, magnesium oxide, and several metals in molten calcium chloride with chlorine

    International Nuclear Information System (INIS)

    In this paper corrosion studies are described in a molten calcium chloride environment sparged with chlorine gas at 850 degrees C, both in the melt and in the gas phase above the salt, in support of efforts at Westinghouse Savannah River Company to develop more resistant materials of construction for molten salt processing of plutonium. Corrosion rates and electron microscope analyses are reported for Inconel alloys 601 and 617, tantalum, tungsten, magnesium oxide, and silicon nitride. Silicon nitride exhibited the greatest resistance, showing 2 · h loss in both melt and vapor None of the metallic coupons withstood the chlorine vapor environment, although Inconel indicated resistance immersed in the melt if protected from chlorine gas

  12. Doping of a high calcium oxide metaphosphate glass with titanium dioxide

    OpenAIRE

    Abou Neel, Ensanya A; Chrzanowski, Wojciech; Valappil, Sabeel P.; O'Dell, Luke A.; Pickup, David M.; Smith, Mark E; Newport, Robert J.; Knowles, Jonathan C

    2009-01-01

    This study investigates the effect of doping a high calcium oxide containing metaphosphate glass series (CaO)(40)(Na2O)(10)(P2O5)(50) with TiO2 (1, 3, and 5 mol%). TiO2 incorporation increased the density and glass transition temperature while reduced the degradation rate (5 mol% in particular) by twofold compared with (CaO)30 system reported previously. This has been confirmed by ion release and the minimal pH changes. TiP2O7, NaCa(PO3)(3) and CaP2O6 phases were detected for all TiO2-contain...

  13. Role of barium nitrate on the sulfur fixation of calcium oxide`

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    In this paper, the effect of Ba(NO3)2 on the efficiency of sulfur fixation of calcium oxide during coal combustion was studied. The results showed that addition of barium nitrate to the CaO can enhance the sulfur removal rate of CaO significantly. The X-ray diffraction spectrum of residual ash of coal added some sulfur fixative expressed that Ba2+ can form a compound of Ba-Al-Si-O which encloses the CaSO4 to prevent it's decomposition, so Ba2+ can improve the action of sulfur fixation of CaO. The combustion character os the original coal and original coal added sulfur fixative was researched with thermal-gravity analyzer and the results expressed that adding some sulfur fixative to the coal will make the combustion character of coal change little.

  14. Iron oxide functionalized graphene oxide as an efficient sorbent for dispersive micro-solid phase extraction of sulfadiazine followed by spectrophotometric and mode-mismatched thermal lens spectrometric determination.

    Science.gov (United States)

    Kazemi, Elahe; Dadfarnia, Shayessteh; Haji Shabani, Ali Mohammad; Abbasi, Amir; Rashidian Vaziri, Mohammad Reza; Behjat, Abbas

    2016-01-15

    A simple and rapid dispersive micro-solid phase extraction (DMSPE) combined with mode-mismatched thermal lens spectrometry as well as fiber optic linear array spectrophotometry was developed for the separation, extraction and determination of sulfadiazine. Graphene oxide was synthesized using the modified Hummers method and functionalized with iron oxide nanoparticles by means of a simple one step chemical coprecipitation method. The synthesized iron oxide functionalized graphene oxide was utilized as an efficient sorbent in DMSPE of sulfadiazine. The retained analyte was eluted by using 180µL of a 6:4 mixture of methanol/acetic acid solution and was spectrophotometrically determined based on the formation of an azo dye through coupling with thenoyltrifluoroacetone. Under the optimized conditions, with the application of spectrophotometry technique and with a sample volume of 100mL, the method exhibited a linear dynamic range of 3-80µg L(-1) with a detection limit of 0.82µg L(-1), an enrichment factor of 200 as well as the relative standard deviations of 2.6% and 4.3% (n=6) at 150µg L(-1) level of sulfadiazine for intra- and inter-day analyses, respectively. Whereas, through the application of the thermal lens spectrometry and a sample volume of 10mL, the method exhibited a linear dynamic range of 1-800µg L(-1) with a detection limit of 0.34µg L(-1) and the relative standard deviations of 3.1% and 5.4% (n=6) at 150µg L(-1) level of sulfadiazine for intra- and inter-day analyses, respectively. The method was successfully applied to the determination of sulfadiazine in milk, honey and water samples. PMID:26592647

  15. Effect of calcium on adsorptive removal of As(III) and As(V) by iron oxide-based adsorbents

    KAUST Repository

    Uwamariya, V.

    2014-06-25

    The effects of calcium on the equilibrium adsorption capacity of As(III) and As(V) onto iron oxide-coated sand (IOCS) and granular ferric hydroxide (GFH) were investigated through batch experiments, rapid small-scale column tests (RSSCT) and kinetics modelling. Batch experiments showed that at calcium concentrations≤20 mg/L, high As(III) and As(V) removal efficiencies by IOCS and GFH are achieved at pH 6. An increase of the calcium concentration to 40 and 80 mg/L reversed this trend, giving higher removal efficiencies at higher pH (8). The adsorption capacities of IOCS and GFH at an equilibrium arsenic concentration of 10 g/L were found to be between 2.0 and 3.1 mg/g for synthetic water without calcium and between 2.8 and 5.3 mg/g when 80 mg/L of calcium was present at the studied pH values. After 10 hours of filter run in RSSCT, approximately 1000 empty bed volumes, the ratios of C/Co for As(V) were 26% and 18% for calcium-free model water; and only 1% and 0.2% after addition of 80 mg/L of Ca for filter columns with IOCS and GFH, respectively. The adsorption of As(III) and As(V) onto GFH follows a second-order reaction, with and without addition of calcium. The adsorption of As(III) and As(V) onto IOCS follows a first-order reaction without calcium addition, and moves to the second-reaction-order kinetics when calcium is added. Based on the intraparticle diffusion model, the main controlling mechanism for As(III) adsorption is intraparticle diffusion, while surface diffusion contributes greatly to the adsorption of As(V).

  16. Oxidized low density lipoprotein (LDL) and platelet intracellular calcium: interaction with nitric oxide.

    Science.gov (United States)

    Zuliani, V; Tommasol, R; Gaino, S; Degan, M; Cominacini, L; Davoli, A; Lechi, C; Lechi, A; Minuz, P

    1998-01-01

    The present study tested the effects of ox-low density lipoprotein (LDL) on nitric oxide (NO)-dependent decrease in agonist-stimulated [Ca2+]i. The effects of ox-LDL on platelet aggregation were also evaluated. Platelets loaded with FURA 2 AM (2 micromol/litre) were incubated with NO-donors for 2-10 min to obtain a 40-50% reduction in \\[Ca2+]i and with NO-donors plus ox-LDL (100 microg of protein/ml). Thrombin (0.03 U/ml) was used as an agonist. In some experiments 8-Br-cGMP (0.5-1 mmol/l) was used to investigate the NO-dependent intraplatelet signalling system. Slightly oxidized LDL was obtained by leaving native LDL in the light at room temperature for at least 7 days. Ox-LDL did not cause any increase in thrombin-induced [Ca2+] (control: 215.4 +/- 44.3 nmol/l, ox-LDL 223.4 +/- 35.3 nmol/l, M +/- SEM; n = 8) and platelet aggregation (control: 78.7 +/- 4.9% , ox-LDL: 78.9 +/- 4.2% , n = 12). Ox-LDL antagonized the effects of NO-donors on platelet [Ca2+]i (NO-donor: 137.4 +/- 22.1 nmol/l, NO + ox-LDL: 177.3 +/- 27.6 nmol/l, n = 11; P < 0.001) and platelet aggregation (NO-donor: 15.4 +/- 3.4% , NO + ox-LDL: 28.9 +/- 3.8%, n = 24; P < 0.001). Ox-LDL did not affect the inhibitory activities of 8-Br-cGMP on platelet aggregation (8-Br-cGMP: 22.0 +/- 8.5%, 8-Br-cGMP + ox-LDL: 19.3 +/- 7.8%, n = 5) and platelet [Ca2+]i . In conclusion, slightly oxidized LDL does not directly activate platelets and does not i affect the intracellular NO-dependent signalling system. The present results suggest that LDL reduces the antiplatelet activity of NO mainly by preventing its biological effects. PMID:16793716

  17. Sorption of europium (3) by polymer sorbents with grafted heterocyclic nitrogen-containing groupings

    International Nuclear Information System (INIS)

    On polymer sorbents (copolymer of styrene-divinylbenzene) with grafted heterocyclic nitrogen-containing functional groupings of tetrazole, triazole and imidazole (sorbents 1,2,3, respectively). It is stated that europium sorption takes place from neutral solutions in presence of organic solvents. Luminescent properties of europium on sorbent are used to develope methods of its determination in high purity lanthanide and yttrium oxides. Europium determination limits consist 7.5·10-5μg/ml on 1 and 3 sorbents and 1.5·10-4μg/ml on sorbent 2, Sp value is 0.089 and 0.075, respectivaly

  18. Influence of extra-cellular and intra-cellular acting thiol oxidants on the 45calcium uptake by the islets of Langerhans of the rat

    International Nuclear Information System (INIS)

    The glucose-stimulated calcium uptake by the islets of Langerhans is dependent on the intra-cellular GSH/GSSG ratios. The inhibition of calcium uptake is not the consequence of a direct oxidation of membrane-fixed thiol groups. In contrast, direct oxidation of extra cellular thiols leads to an increase in calcium uptake when intra-cellular oxidation is simultaneously prevented. Since this effect only occurs at high intra-cellular GSH/GSSG ratios it can be assumed that the redox state of extra-cellular thiols is dependent on the redox state of the intra-cellular GSH/GSSG ratios. These findings support the theory that the oxidation of extra-cellular thiols by thiol oxidants leads to an increase in calcium uptake and that the extent of uptake is higher, the more the redox state of the extra-cellular thiols tends towards the reduced state prior to oxidation. (orig./MG)

  19. Enhanced durability of desulfurization sorbents for fluidized-bed applications

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, R.P.; Gangwal, S.K.

    1991-06-01

    Advanced integrated gasification combined cycle (IGCC) power systems require the development of high-temperature desulfurization sorbents capable of removing hydrogen sulfide from coal gasifier down to very low levels. The objective of this investigation was to identify and demonstrate methods for enhancing the long-term chemical reactivity and mechanical strength of zinc ferrite, a leading regenerable sorbent, for fluidized-bed applications. Fluidized sorbent beds offer significant potential in IGCC systems because of their ability to control the highly exothermic regeneration involved. However, fluidized beds require a durable, attrition-resistant sorbent in the 100--300 {mu}m size range. A bench-scale high-temperature, high- pressure (HTHP) fluidized-bed reactor (7.6-cm I.D.) system capable of operating up to 24 atm and 800{degree}C was designed, built and tested. A total of 175 sulfidation-regeneration cycles were carried out using KRW-type coal gas with various zinc ferrite formulations. A number of sorbent manufacturing techniques including spray drying, impregnation, crushing and screening, and granulation were investigated. While fluidizable sorbents prepared by crushing durable pellets and screening had acceptable sulfur capacity, they underwent excessive attrition during multicycle testing. The sorbent formulations prepared by a proprietary technique were found to have excellent attrition resistance and acceptable chemical reactivity during multicycle testing. However, zinc ferrite was found to be limited to 550{degree}C, beyond which excessive sorbent weakening due to chemical transformations, e.g., iron oxide reduction, was observed.

  20. Inorganic sorbents for removal of radioactivity from aqueous waste streams: 1. Development of seeded ultrafiltration. 2. Ion exchange properties of hydrous titanium oxide. 3. The novel absorber evaluation club

    International Nuclear Information System (INIS)

    This report describes briefly three areas of work involving inorganic sorbents that have been carried out at AEA Technology, Harwell during the course of the Co-ordinated Research Programme (CRP). 1. Seed ultrafiltration, in which finely divided sodium nickel hexacyanoferrate (II), zirconium phosphate and a hydrous titanium oxide were used as a 'seed' cocktail, in combination with cross-flow membrane filtration, to decontaminate a simulate PWR primary coolant. All but one of the eight radionuclides present were reduced in concentration by a factor of ten or more. 2. Some data on the ion-exchange properties of hydrous titanium oxides are presented. These include the cation exchange capacity for barium (as a stand-in for radium), kinetics of sorption and Na:Ti ratio at different values of pH. 3. Some of the data collected from tests carried out by the Novel Absorber Evaluation Club are presented for a number of sorbents that have been examined during the period of this CRP. (author). 1 ref., 5 figs, 6 tabs

  1. Preparation of a graphene oxide/silica composite modified with nitro-substituted tris(indolyl)methane as a solid-phase extraction sorbent for the extraction of organic acids.

    Science.gov (United States)

    Wang, Na; Yu, Hui; Shao, Shijun

    2016-05-01

    This paper describes the use of graphene oxide/silica modified with nitro-substituted tris(indolyl)methane as a solid-phase extraction sorbent for the determination of organic acids. The resultant graphene oxide/silica modified with nitro-substituted tris(indolyl)methane was characterized by FTIR spectroscopy and adsorption experiments. Solid-phase extraction parameters such as sorbent type, sample solution pH, sample loading rate, eluent salt concentration, eluent methanol concentration, elution rate, sample loading, and elution volume were optimized. The method showed good precision, accuracy, sensitivity, and linear response for organic acids analysis over a concentration range of 1-100 μg/L for benzoic acid, p-methoxybenzoic acid, and salicylic acid and 5-100 μg/L for the remaining organic acids (cinnamic acid, p-chlorobenzoic acid, and p-bromobenzoic acid) with coefficients of determination (r(2) ) of higher than 0.9957. Limits of detection from 0.50 to 1.0 μg/L for six organic acids were achieved. The developed method was successfully applied to determine organic acids in real samples. PMID:26969351

  2. Oxidative Stress Tolerance by Calcium and Histidine in Two Tomato Cultivars Under Nickel Stress

    Directory of Open Access Journals (Sweden)

    Mozafari H.

    2014-05-01

    Full Text Available We investigated calcium (Ca and L-histidine (His interaction on nickel (Ni-induced oxidative stress tolerance in two tomato (Solanum lycopersicum Mill. cultivars including Cal-J N3 and Petoearly CH. CaCl2 (0 and 300 µM and L-histidine (0 and 300 µM effects on the oxidative responses in these cultivars cultured were compared in the hydroponic media under Ni stress (NiSO4; 0,150 and 300 µM. The activities of antioxidative enzymes including catalase (CAT, guaiacol peroxidase (GPX, ascorbate peroxidase (APX, superoxide dismutase (SOD and total content of proteins, malondialdehyde (MDA, other aldehydes, H2O2, Ca2+, Ni2+, ascorbate (ASC, dehydroascorbate (DHA and electrolytes leakage (EL were determined. The obtained results indicated that the application of Ca and His generally reduced oxidative markers such as the contents of EL, H2O2, MDA and activity of CAT as well as the Ni2+content of root and shoot organs under nickel toxicity, while application of Ni treatment without Ca+His increased these oxidative parameters and accumulation of Ni2+, compared to the control. Applying Ni without Ca and His has resulted in reduction of GPX, APX and SOD activities as well as concentrations of root and shoot Ca2+and ASC in the two mentioned cultivars. Application of Ca and His lead to the elevated contents of Ca2+ and ASC, increased activities of GPX, APX and SOD as well as inhibition of Ni2+ accumulation differently in both cultivars. Ca and His also alleviated the adverse effects of Ni stress on the selected investigated parameters especially in Petoearly CH cultivar. Thus, interaction of Ca and His appeared to improve adaptive responses to Ni stress leading to decreasing Ni-induced oxidative stress in the tomato plants. Therefore, our results suggest that Ca+His alleviated nickel-induced oxidative stress by uptake and inhibition of translocation of Ni2+ plus Ni chelating mechanism improvement in the tomato cultivars.

  3. KINETICS OF HOT-GAS DESULFURIZATION SORBENTS FOR TRANSPORT REACTORS; ANNUAL

    International Nuclear Information System (INIS)

    Hot-gas desulfurization for the integrated gasification combined cycle (IGCC) process has been investigated by many researchers to remove effectively hydrogen sulfide with various metal oxide sorbents at elevated temperatures. Various metal oxide sorbents are formulated with metal oxides such as Fe, Co, Zn, and Ti. Initial reaction kinetics of formulated sorbents with hydrogen sulfide is studied in the presence of various amounts of moisture and hydrogen at various reaction temperatures. The objectives of this research are to study initial reaction kinetics for a sorbent-hydrogen sulfide heterogeneous reaction system, to investigate effects of concentrations of hydrogen sulfide, hydrogen, and moisture on dynamic absorption of H(sub 2)S into sorbents, and to evaluate effects of temperature and sorbent amounts on dynamic absorption of H(sub 2)S into sorbents. Experimental data on initial reaction kinetics of hydrogen sulfide with metal oxide sorbents were obtained with a 0.83-cm(sup 3) differential reactor. The reactivity of MCRH-67 was examined in this report. This sorbent was obtained from the Research Triangle Institute (RTI). The sorbent in the form of 130 mm particles are reacted with 18000-ppm hydrogen sulfide at 350-525 C. The range of space time of reaction gas mixtures is 0.069-0.088 s. The range of reaction duration is 4-180 s

  4. ADVANCED SORBENT DEVELOPMENT

    Energy Technology Data Exchange (ETDEWEB)

    Javad Abbasian

    2000-01-01

    The overall objective of this program was to develop regenerable sorbents for use in the temperature range of 343 to 538 C (650 to 1000 F) to remove hydrogen sulfide (H{sub 2}S) from coal-derived fuel gases in a fluidized-bed reactor. The goal was to develop sorbents that are capable of reducing the H{sub 2}S level in the fuel gas to less than 20 ppmv in the specified temperature range and pressures in the range of 1 to 20 atmospheres, with chemical characteristics that permit cyclic regeneration over many cycles without a drastic loss of activity, as well as physical, characteristics that are compatible with the fluidized bed application. This topical report focuses on the investigation directed toward preparation of zinc-based sorbents using the sol-gel approach that has been shown to require only a moderate temperature for calcination, while resulting in significantly more attrition-resistant sorbents. The sorbents prepared in this part of the investigation and the results from their evaluation in packed-bed and fluidized-bed reactors are described in this report.

  5. CO2 capture performance of synthetic sorbent prepared from carbide slag and aluminum nitrate hydrate by combustion synthesis

    International Nuclear Information System (INIS)

    Highlights: • Carbide slag as material is used to prepare CO2 sorbent by combustion synthesis. • Glycerol addition in preparation of synthetic sorbent improves its CO2 uptake. • The feasible combustion synthesis temperature for sorbent preparation is 800 °C. • Synthetic sorbent (mass ratio of CaO:Ca3Al2O6 = 73:27) shows higher CO2 uptake. • Synthetic sorbent possesses much higher sintering resistance than carbide slag. - Abstract: A new CO2 sorbent was prepared from carbide slag, aluminum nitrate hydrate and glycerol water solution by combustion synthesis method. The effects of the sorbent preparation conditions (glycerol addition, combustion synthesis temperature, ratio of carbide slag to aluminum nitrate hydrate) and carbonation/calcination conditions (temperature, atmosphere and time) on CO2 capture performance of the synthetic sorbent were investigated in the calcium looping cycles. The addition of glycerol during the sorbent preparation exhibits an improvement on the cyclic CO2 capture capacity. It was also found that the optimal combustion synthesis temperature for the synthetic sorbent was in the range of 750–800 °C. The synthetic sorbent contained the mass ratio of CaO derived from carbide slag to Al2O3 derived from aluminum nitrate hydrate = 90:10 exhibited higher CO2 capture capacity (0.38 g CO2/g sorbent after 50 cycles). X-ray diffraction analysis showed that the main compounds of the synthetic sorbent were CaO and Ca3Al2O6 by X-ray diffraction analysis. The synthetic sorbent showed higher CO2 capture capacity than the carbide slag under severe calcination conditions (950 °C, CO2) and at short carbonation time (<5 min). From the present investigation, it shows that a high active synthetic CO2 sorbent could be obtained using the carbide slag in the calcium looping technology

  6. The inclusion of MgH2 into iron oxide and nickel oxide modified mesoporous carbon sorbent, an investigation on hydrogen production

    Directory of Open Access Journals (Sweden)

    Moradi Seyyed Ershad

    2012-01-01

    Full Text Available In the present work, we investigated the hydrogen desorption properties of nano-sized MgH2 that was loaded on ordered mesoporous carbon (OMC surface that had been already modified with nickel and iron oxide nanoparticles. The surface modified mesoporous carbon was characterized by BET surface area and X-ray diffraction (XRD analysis. The amount of MgH2 on the carbon surface was confirmed by thermogravimetric analysis (TGA. Dehydrogenation data of MgH2 on the ordered mesoporous carbon were collected for the pressure up to 8 MPa (80 bar at 500 K. The incorporated MgH2 on nickel oxide-mesoporous carbon nanocomposite had faster dehydrogenation kinetics compared to incorporated MgH2 on iron oxide-mesoporous carbon nanocomposite as well as incorporated MgH2 on mesoporous carbon. This can be attributed to the particle size of the former being smaller than that of the latter, as well as much accessible nanosized surface of loaded MgH2.

  7. Characteristics and reactivity of rapidly hydrated sorbent for semidry flue gas desulfurization.

    Science.gov (United States)

    Zhang, Jie; You, Changfu; Zhao, Suwei; Chen, Changhe; Qi, Haiying

    2008-03-01

    Semidry flue gas desulfurization with a rapidly hydrated sorbent was studied in a pilot-scale circulating fluidized bed (CFB) experimental facility. The desulfurization efficiency was measured for various operating parameters, including the sorbent recirculation rate and the water spray method. The experimental results show that the desulfurization efficiencies of the rapidly hydrated sorbent were 1.5-3.0 times higher than a commonly used industrial sorbent for calcium to sulfur molar ratios from 1.2 to 3.0, mainly due to the higher specific surface area and pore volume. The Ca(OH)2 content in the cyclone separator ash was about 2.9% for the rapidly hydrated sorbent and was about 0.1% for the commonly used industrial sorbent, due to the different adhesion between the fine Ca(OH)2 particles and the fly ash particles, and the low cyclone separation efficiency for the fine Ca(OH)2 particles that fell off the sorbent particles. Therefore the actual recirculation rates of the active sorbent with Ca(OH)2 particles were higher for the rapidly hydrated sorbent, which also contributed to the higher desulfurization efficiency. The high fly ash content in the rapidly hydrated sorbent resulted in good operating stability. The desulfurization efficiency with upstream water spray was 10-15% higher than that with downstream water spray. PMID:18441824

  8. Space-filling polyhedral sorbents

    Science.gov (United States)

    Haaland, Peter

    2016-06-21

    Solid sorbents, systems, and methods for pumping, storage, and purification of gases are disclosed. They derive from the dynamics of porous and free convection for specific gas/sorbent combinations and use space filling polyhedral microliths with facial aplanarities to produce sorbent arrays with interpenetrating interstitial manifolds of voids.

  9. CALCIUM HYDROXIDE AND CALCIUM CARBONATE PARTICLE SIZE EFFECTS ON REACTIVITY WITH SULFUR DIOXIDE

    Science.gov (United States)

    The paper reports results of measurements of the effect of in situ calcium-based sorbent particle size upon reactivity with 3000 ppm SO2 in an 1100 c drop-tube furnace, using on-line collection of the reacted sorbent with a particle cascade impactor. Significant agglomeration occ...

  10. Laboratory Synthesized Calcium Oxide and Calcium Hydroxide Grains: A Candidate to Explain the 6.8 Micron Band

    Science.gov (United States)

    Kimura, Yuki; Nuth, Joseph A., III

    2005-01-01

    We will demonstrate that CaO and Ca(OH)2 are excellent candidates to explain the 6.8 microns feature, which is one of the most obscure features in young stellar objects. We discuss the condensation of CaO grains and the potential formation of a Ca(OH)2 surface layer. The infrared spectra of these grains are compared with the spectra of fifteen young stellar objects. We note that CaO-rich grains are seen in all meteoritic CAIs (calcium-aluminum-rich inclusions) and the 6.8 micron feature has only been observed in young stellar objects. Therefore, we consider CaO grains to be a plausible candidate to explain the 6.8 microns feature and hypothesize that they are produced in the hot interiors of young stellar environments.

  11. Formate oxidation-driven calcium carbonate precipitation by Methylocystis parvus OBBP.

    Science.gov (United States)

    Ganendra, Giovanni; De Muynck, Willem; Ho, Adrian; Arvaniti, Eleni Charalampous; Hosseinkhani, Baharak; Ramos, Jose Angel; Rahier, Hubert; Boon, Nico

    2014-08-01

    Microbially induced carbonate precipitation (MICP) applied in the construction industry poses several disadvantages such asammonia release to the air and nitric acid production. An alternative MICP from calcium formate by Methylocystis parvus OBBP is presented here to overcome these disadvantages. To induce calcium carbonate precipitation, M. parvus was incubated at different calcium formate concentrations and starting culture densities. Up to 91.4% ± 1.6% of the initial calcium was precipitated in the methane-amended cultures compared to 35.1% ± 11.9% when methane was not added. Because the bacteria could only utilize methane for growth, higher culture densities and subsequently calcium removals were exhibited in the cultures when methane was added. A higher calcium carbonate precipitate yield was obtained when higher culture densities were used but not necessarily when more calcium formate was added. This was mainly due to salt inhibition of the bacterial activity at a high calcium formate concentration. A maximum 0.67 ± 0.03 g of CaCO3 g of Ca(CHOOH)2(-1) calcium carbonate precipitate yield was obtained when a culture of 10(9) cells ml(-1) and 5 g of calcium formate liter(-)1 were used. Compared to the current strategy employing biogenic urea degradation as the basis for MICP, our approach presents significant improvements in the environmental sustainability of the application in the construction industry. PMID:24837386

  12. Endogenous nitric oxide mediates alleviation of cadmium toxicity induced by calcium in rice seedlings

    Institute of Scientific and Technical Information of China (English)

    Long Zhang; Zhen Chen; Cheng Zhu

    2012-01-01

    The effect of calcium chloride (CaCl2) on rice seedling growth under cadmium chloride (CdCl2) stress,as well as the possible role of endogenous nitric oxide (NO) in this process,was studied.The growth of rice seedlings was seriously inhibited by CdCl2,and the inhibition was significantly mitigated by CaCl2.However,hemoglobin (Hb) and 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline1-oxyl-3-oxide (cPTIO) weakened the promotion effect of CaCl2.The resuhs of NO fluorescence localization suggest that growth accelerated by CaCl2 might be associated with elevated NO levels.The content of Cd,protein thiols (PBT),and nonprotein thiols (NPT) in cell walls,cell organelles,and soluble fractions,respectively,of rice seedlings decreased considerably in the presence of CaCl2,whereas the content of pectin,hemicellulose 1 (HC1),and hemicellulose 2 (HC2) increased significantly.Elimination of endogenous NO in Cd+Ca treatment could promote the transportation of Cd2+ to cell organelles and soluble fractions and increase the content of NPT and PBT in leaves.In addition,transportation of Cd2+ to cell organelles and soluble fractions was retarded in roots,the content of NPT increased,and the content of PBT decreased.With elimination of endogenous NO in Cd+Ca treatment,the content of pectin,HC 1,and HC2 decreased significantly.Thus,Ca may alleviate Cd toxicity via endogenous NO with variation in the levels of NPT,PBT,and matrix polysaccharides.

  13. Multivariate regression models for the simultaneous quantitative analysis of calcium and magnesium carbonates and magnesium oxide through drifts data

    Directory of Open Access Journals (Sweden)

    Marder Luciano

    2006-01-01

    Full Text Available In the present work multivariate regression models were developed for the quantitative analysis of ternary systems using Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS to determine the concentration in weight of calcium carbonate, magnesium carbonate and magnesium oxide. Nineteen spectra of standard samples previously defined in ternary diagram by mixture design were prepared and mid-infrared diffuse reflectance spectra were recorded. The partial least squares (PLS regression method was applied to the model. The spectra set was preprocessed by either mean-centered and variance-scaled (model 2 or mean-centered only (model 1. The results based on the prediction performance of the external validation set expressed by RMSEP (root mean square error of prediction demonstrated that it is possible to develop good models to simultaneously determine calcium carbonate, magnesium carbonate and magnesium oxide content in powdered samples that can be used in the study of the thermal decomposition of dolomite rocks.

  14. Calcium zirconate: preparation, properties and application to the solid oxide galvanic cells

    International Nuclear Information System (INIS)

    Stoichiometric, and doped with a small amount of CaO, calcium zirconate dense samples were prepared. X-ray analysis revealed that the solid solution was formed in the concentration range up to x=0.06 in the {xCaO+(1-x)CaZrO3} mixture. The activity of CaO in the solid solution was determined by the emf method at the temperatures 1073 and 1273 K. The electrical conductivity was measured using both dc four-probe and ac impedance spectroscopy methods. The maximum conductivity values were observed for the sample with x=0.06. This sample was used for further investigation. The oxygen-ion transference number, estimated by the emf method, appeared to be close to unity. The partial electronic (electron and electron hole) conductivities, deduced from current-potential curves following the polarisation method, were found to be very small with respect to total electrical conductivity. Then, the sample was tested as an electrolyte in solid oxide galvanic cells. In this way, the values of the standard free enthalpy of formation of cobalt and nickel silicates at the temperatures 1073 and 1273 K were determined and compared with those obtained by other authors

  15. Qualitative parameters of sugarcane silages treated with urea and calcium oxide

    Directory of Open Access Journals (Sweden)

    Susi Cristina dos Santos Guimarães Martins

    2015-04-01

    Full Text Available The objective was to evaluate the fermentation parameters, chemical composition and fractionation of carbohydrates of sugarcane silages treated with urea and calcium oxide (CaO. Upon ensiling, the treatments applied to the sugarcane were: 1% urea; 0.5% urea + 0.5% CaO; and 1% CaO, in relation to a control silage, without additive. The chemical additives (urea and CaO were added at ensiling, in an amount calculated based on the fresh matter (as is. A completely randomized design consisting of four treatments (silages and nine replicates was adopted. The material was conditioned in PVC mini-silos for five months. At the end of the storage period, silos were weighed again and samples were collected to quantify the losses caused by fermentation, dry matter recovery, pH, and ammonia nitrogen (N-NH3 of the silages and to evaluate the chemical composition and fractionation of carbohydrates. The silage with 1% CaO showed the highest recovery of dry matter, and in terms of carbohydrate fractionation, it showed the highest levels of soluble and potentially soluble carbohydrates. Addition of 1% CaO during ensiling reduces the fermentation losses of sugarcane silages.

  16. Evaluation of oxidized buckypaper as material for the solid phase extraction of cobalamins from milk: Its efficacy as individual and support sorbent of a hydrophilic-lipophilic balance copolymer.

    Science.gov (United States)

    Pérez-Fernández, V; Gentili, A; Martinelli, A; Caretti, F; Curini, R

    2016-01-01

    This work describes a new analytical method for the determination of four cobalamins (adenosylcobalamin (AdoCbl), methylcobalamin (MeCbl), hydroxocobalamin (OHCbl) and cyanocobalamin (CNCbl)) in cow's milk. The extraction procedure is fast and based on dilution/protein precipitation of a milk sample with 50mM sodium acetate buffer (pH 4.6), followed by solid phase extraction (SPE) of the filtered supernatant. Relative recoveries higher than 60% have been obtained for all the cobalamins by combining two different types of sorbents in the same SPE cartridge: two disks of buckypaper (BP), a nanoporous felt composed of oxidized multiwalled carbon nanotubes (MWCNTs), separated by a Teflon frit from OASIS HLB (500mg), a hydrophilic-lipophilic balance copolymer. Before its use as sorbent, BP was characterized in terms of porosity, permeability, surface area, specific adsorption capacity and tested for a potential reuse after adequate chemical regeneration. The analysis of the extracts was performed by liquid chromatography (LC) coupled to tandem mass spectrometry (MS/MS) on an analytical C18 column in less than 10min. After validation, the method was applied to the determination of the natural content of the four B12 homologues in cow's milk samples, providing data lacking in the literature. PMID:26265001

  17. Advanced sorbent development progam; development of sorbents for moving-bed and fluidized-bed applications

    International Nuclear Information System (INIS)

    The integrated gasification combined cycle (IGCC) power system using high-temperature coal gas cleanup is one of the most promising advanced technologies for the production of electric power from coal in an environmentally acceptable manner. Unlike conventional low-temperature cleanup systems that require costly heat exchangers, high-temperature coal gas cleanup systems can be operated near 482-538 C (900-1000F) or higher, conditions that are a closer match with the gasifier and turbine components in the IGCC system, thus resulting is a more efficient overall system. GE is developing a moving-bed, high-temperature desulfurization system for the IGCC power cycle in which zinc-based regenerable sorbents are currently being used as desulfurization sorbents. Zinc titanate and other proprietary zinc-based oxides are being considered as sorbents for use in the Clean Coal Technology Demonstration Program at Tampa Electric Co.s (TECo) Polk Power Station. Under cold startup conditions at TECo, desulfurization and regeneration may be carried out at temperatures as low as 343 C (650 F), hence a versatile sorbent is desirable to perform over this wide temperature range. A key to success in the development of high-temperature desulfurization systems is the matching of sorbent properties for the selected process operating conditions, namely, sustainable desulfurization kinetics, high sulfur capacity, and mechanical durability over multiple cycles. Additionally, the sulfur species produced during regeneration of the sorbent must be in a form compatible with sulfur recovery systems, such as sulfuric acid or elemental sulfur processes. The overall objective of this program is to develop regenerable sorbents for hydrogen sulfide removal from coal-derived fuel gases in the temperature range 343-538 C (650-1000 F). Two categories of reactor configurations are being considered: moving-bed reactors and fluidized-bed (bubbling and circulating) reactors. In addition, a cost assessment and

  18. ADVANCED SORBENT DEVELOPMENT PROGRAM DEVELOPMENT OF SORBENTS FOR MOVING-BED AND FLUIDIZED-BED APPLICATIONS

    Energy Technology Data Exchange (ETDEWEB)

    R.E Ayala; V.S. Venkataramani; Javad Abbasian; Rachid B. Slimane; Brett E. Williams; Minoo K. Zarnegar; James R. Wangerow; Andy H. Hill

    2000-03-31

    The integrated gasification combined cycle (IGCC) power system using high-temperature coal gas cleanup is one of the most promising advanced technologies for the production of electric power from coal in an environmentally acceptable manner. Unlike conventional low-temperature cleanup systems that require costly heat exchangers, high-temperature coal gas cleanup systems can be operated near 482-538 C (900-1000 F) or higher, conditions that are a closer match with the gasifier and turbine components in the IGCC system, thus resulting is a more efficient overall system. GE is developing a moving-bed, high-temperature desulfurization system for the IGCC power cycle in which zinc-based regenerable sorbents are currently being used as desulfurization sorbents. Zinc titanate and other proprietary zinc-based oxides are being considered as sorbents for use in the Clean Coal Technology Demonstration Program at Tampa Electric Co.'s (TECo) Polk Power Station. Under cold startup conditions at TECo, desulfurization and regeneration may be carried out at temperatures as low as 343 C (650 F), hence a versatile sorbent is desirable to perform over this wide temperature range. A key to success in the development of high-temperature desulfurization systems is the matching of sorbent properties for the selected process operating conditions, namely, sustainable desulfurization kinetics, high sulfur capacity, and mechanical durability over multiple cycles. Additionally, the sulfur species produced during regeneration of the sorbent must be in a form compatible with sulfur recovery systems, such as sulfuric acid or elemental sulfur processes. The overall objective of this program is to develop regenerable sorbents for hydrogen sulfide removal from coal-derived fuel gases in the temperature range 343-538 C (650-1000 F). Two categories of reactor configurations are being considered: moving-bed reactors and fluidized-bed (bubbling and circulating) reactors. In addition, a cost

  19. ADVANCED SORBENT DEVELOPMENT PROGRAM; DEVELOPMENT OF SORBENTS FOR MOVING-BED AND FLUIDIZED-BED APPLICATIONS

    Energy Technology Data Exchange (ETDEWEB)

    AYALA, R E; VENKATARAMANI, V S

    1998-09-30

    The integrated gasification combined cycle (IGCC) power system using high-temperature coal gas cleanup is one of the most promising advanced technologies for the production of electric power from coal in an environmentally acceptable manner. Unlike conventional low-temperature cleanup systems that require costly heat exchangers, high-temperature coal gas cleanup systems can be operated near 482-538 °C (900-1000 °F) or higher, conditions that are a closer match with the gasifier and turbine components in the IGCC system, thus resulting is a more efficient overall system. GE is developing a moving-bed, high-temperature desulfurization system for the IGCC power cycle in which zinc-based regenerable sorbents are currently being used as desulfurization sorbents. Zinc titanate and other proprietary zinc-based oxides are being considered as sorbents for use in the Clean Coal Technology Demonstration Program at Tampa Electric Co.'s (TECo) Polk Power Station. Under cold startup conditions at TECo, desulfurization and regeneration may be carried out at temperatures as low as 343 °C (650 °F), hence a versatile sorbent is desirable to perform over this wide temperature range. A key to success in the development of high-temperature desulfurization systems is the matching of sorbent properties for the selected process operating conditions, namely, sustainable desulfurization kinetics, high sulfur capacity, and mechanical durability over multiple cycles. Additionally, the sulfur species produced during regeneration of the sorbent must be in a form compatible with sulfur recovery systems, such as sulfuric acid or elemental sulfur processes. The overall objective of this program is to develop regenerable sorbents for hydrogen sulfide removal from coal-derived fuel gases in the temperature range 343-538 °C (650-1000 °F). Two categories of reactor configurations are being considered: moving-bed reactors and fluidized-bed (bubbling and circulating) reactors. In addition, a

  20. Developmental changes of the sensitivity of cardiac and liver mitochondrial permeability transition pore to calcium load and oxidative stress

    Czech Academy of Sciences Publication Activity Database

    Drahota, Zdeněk; Milerová, Marie; Endlicher, R.; Rychtrmoc, D.; Červinková, Z.; Ošťádal, Bohuslav

    2012-01-01

    Roč. 61, Suppl.1 (2012), S165-S172. ISSN 0862-8408 R&D Projects: GA MŠk(CZ) LL1204; GA ČR(CZ) GAP303/12/1162 Institutional support: RVO:67985823 Keywords : mitochondrial permeability transition pore * cardiac mitochondria * liver mitochondria * oxidative stress * calcium load * rat Subject RIV: ED - Physiology Impact factor: 1.531, year: 2012

  1. Design of engineered sorbent barriers

    International Nuclear Information System (INIS)

    A sorbent barrier uses sorbent material such as activated carbon or natural zeolites to prevent the migration of radionuclides from a low-level waste site to the aquifer. The sorbent barrier retards the movement of radioactive contaminants, thereby providing time for the radionuclides to decay. Sorbent barriers can be a simple, effective, and inexpensive method for reducing the migration of radionuclides to the environment. Designing a sorbent barrier consists of using soil and sorbent material properties and site conditions as input to a model which will determine the necessary sorbent barrier thickness to meet contaminant limits. The paper covers the following areas: techniques for measuring sorption properties of barrier materials and underlying soils, use of a radionuclide transport model to determine the required barrier thickness and performance under a variety of site conditions, and cost estimates for applying the barrier

  2. Decontamination of soil by a magnetic sorbent

    International Nuclear Information System (INIS)

    At the former Sered hydrometallurgical plant (Slovakia), the residues of iron-nickel laterite ore (further: SOR) is magnetic and finely-powdered material which is in fact ready-to-use in sorbent-in-pulp separations of radionuclides and toxic elements from suspensions of contaminated material. Feasibility of the magnetic separation process was further investigated as concerns the sorption isotherms, the dynamics of soil-to-sorbent mass transfer, and the reversibility of sorption of the Cs+, Sr2+ and Eu3+ ions. Overall efficiency of the radionuclides transfer from artificially contaminated soil to SOR was evaluated using Freundlich sorption isotherms obtained at various concentration of contaminants, competing ions and pH. Speciation of sorbed radionuclides was obtained by standard sequential leaching procedures (the Tessier and BCR schemes). Radionuclides cesium and europium are bound by the oxide component of the magnetic sorbent, strontium is absorbed by ion-exchange mechanism. A slow and rapid component of transfer rate can be interpreted also by two major adsorption sites. At the mass ratio of magnetic sorbent to soil 5:1 w/w, the removable fraction of mobile Cs-137 and Sr-85 in soil was more than 98%, and 83% for Eu-152. (authors)

  3. Enhanced durability and reactivity for zinc ferrite desulfurization sorbent. Volume 2, Single particle kinetic studies of sulfidation and regeneration reactions of candidate zinc ferrite sorbents

    Energy Technology Data Exchange (ETDEWEB)

    Silaban, A.; Harrison, D.P. [Louisiana State Univ., Baton Rouge, LA (United States). Dept. of Chemical Engineering

    1989-05-02

    AMAX Research & Development Center (AMAX R&D) has been investigating methods for enhancing the reactivity and durability of the zinc ferrite desulfurization sorbent. Zinc ferrite sorbents are intended for use in desulfurization of hot coal gas in integrated gasification combined cycle (IGCC) or molten carbonate fuel cell (MCFC) applications. For the present program, the reactivity of the sorbent may be defined as its sulfur sorption capacity at the breakthrough point and at saturation in a bench-scale, fixed-bed reactor. Durability may be defined as the ability of the sorbent to maintain important physical characteristics such as size, strength, and specific surface area during 10 cycles of sulfidation and oxidation.

  4. Azelnidipine prevents cardiac dysfunction in streptozotocin-diabetic rats by reducing intracellular calcium accumulation, oxidative stress and apoptosis

    Directory of Open Access Journals (Sweden)

    Kain Vasundhara

    2011-11-01

    Full Text Available Abstract Background Numerous evidences suggest that diabetic heart is characterized by compromised ventricular contraction and prolonged relaxation attributable to multiple causative factors including calcium accumulation, oxidative stress and apoptosis. Therapeutic interventions to prevent calcium accumulation and oxidative stress could be therefore helpful in improving the cardiac function under diabetic condition. Methods This study was designed to examine the effect of long-acting calcium channel blocker (CCB, Azelnidipine (AZL on contractile dysfunction, intracellular calcium (Ca2+ cycling proteins, stress-activated signaling molecules and apoptosis on cardiomyocytes in diabetes. Adult male Wistar rats were made diabetic by a single intraperitoneal (IP injection of streptozotocin (STZ. Contractile functions were traced from live diabetic rats to isolated individual cardiomyocytes including peak shortening (PS, time-to-PS (TPS, time-to-relengthening (TR90, maximal velocity of shortening/relengthening (± dL/dt and intracellular Ca2+ fluorescence. Results Diabetic heart showed significantly depressed PS, ± dL/dt, prolonged TPS, TR90 and intracellular Ca2+ clearing and showed an elevated resting intracellular Ca2+. AZL itself exhibited little effect on myocyte mechanics but it significantly alleviated STZ-induced myocyte contractile dysfunction. Diabetes increased the levels of superoxide, enhanced expression of the cardiac damage markers like troponin I, p67phox NADPH oxidase subunit, restored the levels of the mitochondrial superoxide dismutase (Mn-SOD, calcium regulatory proteins RyR2 and SERCA2a, and suppressed the levels of the anti-apoptotic Bcl-2 protein. All of these STZ-induced alterations were reconciled by AZL treatment. Conclusion Collectively, the data suggest beneficial effect of AZL in diabetic cardiomyopathy via altering intracellular Ca2+ handling proteins and preventing apoptosis by its antioxidant property.

  5. Modeling phosphate transport and removal in a compact bed filled with a mineral-based sorbent for domestic wastewater treatment

    Science.gov (United States)

    Herrmann, Inga; Jourak, Amir; Gustafsson, Jon Petter; Hedström, Annelie; Lundström, T. Staffan; Viklander, Maria

    2013-11-01

    Phosphorus filter units containing mineral-based sorbents with a high phosphate (PO4) binding capacity have been shown to be appropriate for removing PO4 in the treatment of domestic wastewater in on-site facilities. However, a better understanding of their PO4 removal mechanisms, and reactions that could lead to the formation of PO4 compounds, is required to evaluate the potential utility of candidate sorbents. Models based on data obtained from laboratory-scale experiments with columns of selected materials can be valuable for acquiring such understanding. Thus, in this study the transport and removal of PO4 in experiments with a laboratory-scale column filled with a commercial silicate-based sorbent were modeled, using the hydro-geochemical transport code PHREEQC. The resulting models, that incorporated the dissolution of calcite, kinetic constrains for the dissolution of calcium oxide (CaO) and wollastonite (CaSiO3), and the precipitation of amorphous tricalcium phosphate, Ca3(PO4)2, successfully simulated the removal of PO4 observed in the experiments.

  6. Seeking homeostasis: Temporal trends in respiration, oxidation, and calcium in SOD1 G93A Amyotrophic Lateral Sclerosis mice

    Directory of Open Access Journals (Sweden)

    Cameron W Irvin

    2015-07-01

    Full Text Available Impairments in mitochondria, oxidative regulation, and calcium homeostasis have been well documented in numerous amyotrophic lateral sclerosis (ALS experimental models, especially in the superoxide dismutase 1 glycine 93 to alanine (SOD1 G93A transgenic mouse. However, the timing of these deficiencies has been debatable. In a systematic review of 45 articles, we examine experimental measurements of cellular respiration, mitochondrial mechanisms, oxidative markers, and calcium regulation. We evaluate the quantitative magnitude and statistical temporal trend of these aggregated assessments in high transgene copy SOD1 G93A mice compared to wild type mice. Analysis of overall trends reveals cellular respiration, intracellular ATP, and corresponding mitochondrial elements (Cox, cytochrome c, complex I, enzyme activity are depressed for the entire lifespan of the SOD1 G93A mouse. Oxidant markers (H2O2, 8OH2’dG, MDA are initially similar to wild type but are double that of wild type by the time of symptom onset despite early post-natal elevation of protective heat shock proteins. All aspects of calcium regulation show early disturbances, although a notable and likely compensatory convergence to near wild type levels appears to occur between 40-80 days (pre-onset, followed by a post-onset elevation in intracellular calcium. The identified temporal trends and compensatory fluctuations provide evidence that the cause of ALS may lay within failed homeostatic regulation, itself, rather than any one particular perturbing event or cellular mechanism. We discuss the vulnerabilities of motoneurons to regulatory instability and possible hypotheses regarding failed regulation and its potential treatment in ALS.

  7. Optimization of transesterification of rubber seed oil using heterogeneous catalyst calcium oxide

    Science.gov (United States)

    Inggrid, Maria; Kristanto, Aldi; Santoso, Herry

    2015-12-01

    Biodiesel is an alternative fuel manufactured with the help of alkali hydroxide catalyst through transesterification reaction of vegetable oil. This study aims to examine methods and the most suitable conditions for transesterification reaction producing biodiesel from crude rubber seed oil by varying process parameters such as the molar ratio of alcohol, CaO amount as the alkaline catalyst, and reaction time. The rubber seed oil has a high level of free fatty acid content, which means the use of homogenous alkaline catalyst gives some technological problems such as soap formation which leaded in difficulty in the separation and purification of the product. Calcium oxide (CaO) is one of the most favorable heterogeneous base catalysts because it's reusable, noncorrosive, and low cost. Pre-treatment was performed by acid esterification with H2SO4 as the catalyst to decrease the content of free fatty acid in the rubber seed oil, in this pretreatment process the 12% FFA of crude oil could be reduced to below 3% FFA. The product after esterification process was then transesterified by alkaline transesterification by varying process parameters to convert triglyceride into biodiesel. The study found that maximum curvature for biodiesel yield occurred at 9:1 molar ratio of alcohol, 5%w catalyst loading, and 3 hours reaction time. Design expert software is used to determine the optimum point from experimental data. The result showed that the optimum yield of methyl ester from transesterification was 73.5 % by mass with 0.69 degree of desirability. The yielded methyl ester was tested for its density, viscosity, acid number, and solubility to meet SNI requirement standards.

  8. Novel Sorbent to Clean Up Biogas for CHPs

    Energy Technology Data Exchange (ETDEWEB)

    Alptekin, Gökhan O. [TDA Research, Incorporated, Wheat Ridge, CO (United States); Jayataman, Ambalavanan [TDA Research, Incorporated, Wheat Ridge, CO (United States); Schaefer, Matthew [TDA Research, Incorporated, Wheat Ridge, CO (United States); Ware, Michael [TDA Research, Incorporated, Wheat Ridge, CO (United States); Hunt, Jennifer [FuelCell Energy, Inc., Danbury, CT (United States); Dobek, Frank [FuelCell Energy, Inc., Danbury, CT (United States)

    2015-05-30

    In this project, TDA Research Inc. (TDA) has developed low-cost (on a per unit volume of gas processed basis), high-capacity expendable sorbents that can remove both the H2S and organic sulfur species in biogas to the ppb levels. The proposed sorbents will operate downstream of a bulk desulfurization system as a polishing bed to provide an essentially sulfur-free gas to a fuel cell (or any other application that needs a completely sulfur-free feed). Our sorbents use a highly dispersed mixed metal oxides active phase with desired modifiers prepared over on a mesoporous support. The support structure allows the large organic sulfur compounds (such as the diethyl sulfide and dipropyl sulfide phases with a large kinetic diameter) to enter the sorbent pores so that they can be adsorbed and removed from the gas stream.

  9. Aerosol Formation during the Combustion of Straw with Addition of Sorbents

    DEFF Research Database (Denmark)

    Zeuthen, Frederik Jacob; Jensen, Peter Arendt; Jensen, Jørgen P.;

    2007-01-01

    experiments showed similar reductions to the ones found in full-scale. When feeding ammonium sulfate, the aerosol mass concentration increased as a result of the feeding method. The chemical compositions of the fine particles suggest that there is chemical equilibrium in the gas for the sulfation reaction at...... mixtures of clay minerals and consist mainly of the oxides from Fe, Al, and Si. The straw used was Danish wheat and seed grass. Measurements were also made with increased flow of primary air. The experiments showed between 46% and 70% reduction in particle mass concentrations when adding ammonium sulfate......, calcium phosphate, Bentonite, ICA5000, and clay. The addition of chalk increased the aerosol mass concentration by 24%. Experiments in a laminar flow aerosol condenser with the six sorbents were carried out in the laboratory using a synthetic flue gas to avoid fluctuations in the alkali feeding. These...

  10. The latest sorbent testing

    International Nuclear Information System (INIS)

    This paper describes an efficient oil spill and chemical hazards response equipment testing program. The type of equipment tested include sorbents, skimmers, pumps, oil-water separators and other mechanical containment and recovery products, with the emphasis on sorbents. The ultimate goal of the testing program developed by Science Applications International Corporation (SAIC Canada) of North York and Ottawa, Ontario, is to develop databases of performance information regarding oil spill equipment which would be tested to internationally recognized standards such as those developed by ASTM for oil spill recovery equipment. To date, a range of performance and handling criteria have been identified which enable end users to determine their priorities and rank sorbents accordingly. A recent successful application of the testing system involved the test of recovery devices designed to deal with some peculiar properties of a heavy oil (extreme viscosity and stickiness), properties which make conventional spill response equipment and techniques ineffective. A more extensive description of the system is promised at the Environment Canada-sponsored Arctic and Marine Oil Spill Technical Seminar scheduled for June in Vancouver

  11. O2/CO2方式下钙基吸收剂在脱硫过程中微观结构变化的研究%MICROSTRUCTURE CHANGES OF CALCIUM--BASED SORBENT DURING DESULFURIZATION IN O2/CO2 MIXTURE

    Institute of Scientific and Technical Information of China (English)

    王宏; 张礼知; 陆晓华; 郑楚光

    2001-01-01

    This paper reports on a study of microstructure changes of calcium-basedsorbent during desulfurization in O2/CO2 mixture. It's found thatpronounced influence on microstructure of calcium-based sorbent lies betweenhigh CO2 concentration and low CO2 concentration. The results indicatethat high CO2 concentration is better for capture of SO2 compared toair condition at high temperature accounting for minimizing sintering of CaOand plugging of reaction product CaSO4.%本文研究了O2/CO2方式下钙基吸收剂在脱硫过程中微观结构的变化。研究结果表明,不同浓度的CO2对孔隙结构的影响完全不同;且提高温度有利于改善高浓度CO2气氛下钙基吸收剂煅烧后的孔隙结构,较之空气气氛,高浓度CO2气氛更有利于高温下炉内喷钙脱硫。

  12. Enhancing the Use of Coals by Gas Reburning - Sorbent Injection Volume 5 - Guideline Manual

    Energy Technology Data Exchange (ETDEWEB)

    None

    1998-06-01

    The purpose of the Guideline Manual is to provide recommendations for the application of combined gas reburning-sorbent injection (GR-SI) technologies to pre-NSPS boilers. The manual includes design recommendations, performance predictions, economic projections and comparisons with competing technologies. The report also includes an assessment of boiler impacts. Two full-scale demonstrations of gas reburning-sorbent injection form the basis of the Guideline Manual. Under the U.S. Department of Energy's Clean Coal Technology Program (Round 1), a project was completed to demonstrate control of boiler emissions that comprise acid rain precursors, specifically oxides of nitrogen (NOX) and sulfur dioxide (S02). Other project sponsors were the Gas Research Institute and the Illinois State Department of Commerce and Community Affairs. The project involved d,emonstrating the combined use of Gas Reburning and Sorbent Injection (GR-SI) to assess the air emissions reduction potential of these technologies.. Three potential coal-fired utility boiler host sites were evaluated: Illinois Power's tangentially-fired 71 MWe (net) Hennepin Unit #1, City Water Light and Power's cyclone- fired 33 MWe (gross) Lakeside Unit #7, and Central Illinois Light Company's wall-fired 117 MWe (net) Edwards Unit #1. Commercial demonstrations were completed on the Hennepin and Lakeside Units. The Edwards Unit was removed from consideration for a site demonstration due to retrofit cost considerations. Gas Reburning (GR) controls air emissions of NOX. Natural gas is introduced into the furnace hot flue gas creating a reducing reburning zone to convert NOX to diatomic nitrogen (N,). Overfire air is injected into the furnace above the reburning zone to complete the combustion of the reducing (fuel) gases created in the reburning zone. Sorbent Injection (S1) consists of the injection of dry, calcium-based sorbents into furnace hot flue gas to achieve S02 capture. `At each site where

  13. Enhancing the Use of Coals by Gas Reburning - Sorbent Injection - Volume 5 - Guideline Manual

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    1998-09-01

    The purpose of the Guideline Manual is to provide recommendations for the application of combined gas reburning-sorbent injection (GR-SI) technologies to pre-NSPS boilers. The manual includes design recommendations, performance predictions, economic projections and comparisons with competing technologies. The report also includes an assessment of boiler impacts. Two full-scale demonstrations of gas reburning-sorbent injection form the basis of the Guideline Manual. Under the U.S. Department of Energy's Clean Coal Technology Program (Round 1), a project was completed to demonstrate control of boiler emissions that comprise acid rain precursors, specifically oxides of nitrogen (NOx) and sulfur dioxide (SO2). Other project sponsors were the Gas Research Institute and the Illinois State Department of Commerce and Community Affairs. The project involved demonstrating the combined use of Gas Reburning and Sorbent Injection (GR-SI) to assess the air emissions reduction potential of these technologies.. Three potential coal-fired utility boiler host sites were evaluated: Illinois Power's tangentially-fired 71 MWe (net) Hennepin Unit #1, City Water Light and Power's cyclone- fired 33 MWe (gross) Lakeside Unit #7, and Central Illinois Light Company's wall-fired 117 MWe (net) Edwards Unit #1. Commercial demonstrations were completed on the Hennepin and Lakeside Units. The Edwards Unit was removed from consideration for a site demonstration due to retrofit cost considerations. Gas Reburning (GR) controls air emissions of NOx. Natural gas is introduced into the furnace hot flue gas creating a reducing reburning zone to convert NOx to diatomic nitrogen (N2). Overfire air is injected into the furnace above the reburning zone to complete the combustion of the reducing (fuel) gases created in the reburning zone. Sorbent Injection (SI) consists of the injection of dry, calcium-based sorbents into furnace hot

  14. Buffering storage of thermal energy by means of the reaction heat of the system calcium oxide/calcium hydroxide. Die Pufferspeicherung thermischer Energie mittels der Waermetoenung des Systems Calciumoxid/Calciumhydroxid

    Energy Technology Data Exchange (ETDEWEB)

    Lehmann, B.

    1986-12-01

    The heat of reaction from the chemical system calcium oxide/calcium hydroxide is used as a buffering facility for thermal energy. In case of forward reaction by adding water to calcium oxide, reaction heat is released that can be used for heating, hot water supply, or for generating steam for industrial purposes. For running the reaction reversely, energy has to be fed into calcium hydroxide to gain calcium oxide. This energy could be supplied by concentrating solar collectors or by high-temperature reactors (HTR) using nuclear energy. Other possible heat sources can be volcanic rocks delivering geothermal energy and refuse-fuelled power plants. Heat at temperatures exceeding 450/sup 0/C has to be furnished for the loading phase. The discharging reaction delivers temperatures up to 400/sup 0/C. For testing this kind of heat storage, a gas-loop has been designed, built and operated. The energy transport in the cycle is provided by an inert gas stream (nitrogen) with variable volumes of steam entrained. The operating conditions were measured by transducers and evaluated with computer programs. The documentation of the measured data and of the deduced values, i.e. energy release and storage rates, pressure drops and behaviour of the storage mass, are presented in this report.

  15. Modification of oxide inclusions present in aluminum-killed low carbon steel by addition of calcium

    Directory of Open Access Journals (Sweden)

    José Carlos S. Pires

    2004-09-01

    Full Text Available A crescente demanda por aços de alta qualidade com elevada limpeza interna tem levado a uma contínua melhoria nas práticas de produção do aço, em especial na etapa de refino secundário. O interesse especial é no controle das inclusões não-metálicas, devido ao seu efeito prejudicial nas etapas subseqüentes (lingotamento e conformação plástica e devido às sua grande influência nas propriedades do produto final. Através do controle do tamanho, da quantidade e da composição química das inclusões, é possível obter um produto final de alta qualidade. O controle da formação das inclusões não-metálicas e a identificação de suas fases constituintes são de suma importância para a obtenção de aços limpos. Nesse trabalho, amostras de aço de baixo teor de carbono, desoxidado ao silício, coletadas em uma indústria siderúrgica, são analisadas e é demonstrado que, pela comparação do teor total de cálcio e de oxigênio no aço, é possível prever os tipos de inclusões presentes no aço.The increasing demand in recent years for high-quality steel products has led to the continuous improvement of steelmaking practices. There is a special interest in the control of non-metallic inclusions due to their harmful effect on the subsequent stages and their great influence on the properties of the final product. Through the control of the amount, size and chemical composition of the inclusions it is possible to obtain a final product of good quality. The control of the formation of non-metallic inclusions and the identification of their constituent phases are of extreme importance for the obtaining of clean steels. In this work, samples collected in a steelmaking process are analyzed and it is demonstrated that by comparing the total calcium and oxygen contents in the steel, it is possible to have an overview of the types of oxide inclusions present.

  16. Zeolite/iron oxide composite as sorbent for magnetic solid-phase extraction of benzene, toluene, ethylbenzene and xylenes from water samples prior to gas chromatography⬜mass spectrometry.

    Science.gov (United States)

    Fernández, Elena; Vidal, Lorena; Canals, Antonio

    2016-08-01

    This study reports a new composite based on ZSM-5 zeolite decorated with iron oxide magnetic nanoparticles as a valuable sorbent for magnetic solid-phase extraction (MSPE). A proposal is made to determine benzene, toluene, ethylbenzene and xylenes (BTEX) as model analytes in water samples using gas chromatography-mass spectrometry. A two-step multivariate optimization strategy, using Plackett⬜Burman and circumscribed central composite designs, was employed to optimize experimental parameters affecting MSPE. The method was evaluated under optimized extraction conditions (i.e., amount of sorbent, 138mg; extraction time, 11min; sample pH, pH of water (i.e., 5.5⬜6.5); eluent solvent volume, 0.5mL; and elution time, 5min), obtaining a linear response from 1 to 100μgL(↙1) for benzene; from 10 to 100μgL(↙1) for toluene, ethylbenzene and o-xylene; and from 10 to 75μgL(↙1) for m,p-xylene. The repeatability of the proposed method was evaluated at a 40μgL(↙1) spiking level and coefficients of variation ranged between 8 and 11% (n=5). Limits of detection were found to be 0.3μgL(↙1) for benzene and 3μgL(↙1) for the other analytes. These values satisfy the current normative of the Environmental Protection Agency and European Union for BTEX content in waters for human consumption. Finally, drinking water, wastewater and river water were selected as real water samples to assess the applicability of the method. Relative recoveries varied between 85% and 114% showing negligible matrix effects. PMID:27373373

  17. Productive performance and efficiency of utilization of the diet components in dairy cows fed castor meal treated with calcium oxide

    OpenAIRE

    Juliana Variz Cobianchi; André Soares de Oliveira; José Maurício de Souza Campos; Amanda Vasconcelos Guimarães; Sebastião de Campos Valadares Filho; Flávio Pereira Cobianchi; Thalita Evani Silva de Oliveira

    2012-01-01

    The effect of replacing of 0; 0.33; 0.67 and 1.0 (kg/kg) of soybean meal (SBM) by undecorticated castor seed meal treated with calcium oxide (CMT - 60 g/kg) was evaluated on performance and efficiency of nutrient utilization in dairy cows. Sixteen Holstein and crossbred cows were distributed in four 4 × 4 latin squares. Animals received concentrated feed at a ratio of 1 kg for 3 kg of milk produced, in the natural matter. The diets had the same amount of nitrogen (150.4 g crude protein/kg DM)...

  18. Correlation of Cell Strain in Single Osteocytes with Intracellular Calcium, but not Intracellular Nitric Oxide, in Response to Fluid Flow

    OpenAIRE

    Rath, Amber L.; Bonewald, Lynda F.; Ling, Jian; Jiang, Jean X.; VAN DYKE, MARK E.; Nicolella, Daniel P

    2010-01-01

    Osteocytes compose 90–95% of all bone cells and are the mechanosensors of bone. In this study, the strain experienced by individual osteocytes resulting from an applied fluid flow shear stress was quantified and correlated to two biological responses measured in real-time within the same individual osteocytes: 1) the upregulation of intracellular calcium and 2) changes in intracellular nitric oxide. Osteocyte-like MLO-Y4 cells were loaded with Fluo-4 AM and DAR-4M and exposed to uniform lamin...

  19. Influence of Electrolyte Composition on the Calcium-Phosphorus compound Coating on Titanium Substrate by Micro-arc Oxidation

    Institute of Scientific and Technical Information of China (English)

    ZHUXiu-hong; WANGCong-zeng; KOUBin-da; SUXue-kuan; ZHANGWen-quan

    2004-01-01

    The compound bioceramic coating containing calcium (Ca) and phosphorus (P) on titanium alloy substrate was prepared by means of micro-arc oxidation (MAO) treatment. The results show that under the different electrolyte the coating with the color of gray or black and surface morphology of cauliflower or honeycomb, where Ca content and P contain can attain 30% and 20% respectively, can be obtained. Meanwhile, the influences of electrolyte temperature, current density and discharge time on morphology and thickness of coating are also discussed here.

  20. Transesterification of Jatropha and Karanja oils by using waste egg shell derived calcium based mixed metal oxides

    International Nuclear Information System (INIS)

    Highlights: • Waste chicken eggshell derived CaO(cesp) based mixed metal oxides were prepared. • Transesterification of high free fatty acid containing non-edible oils were achieved using prepared catalysts. • CaO(cesp) based mixed metal oxides have shown better activity in comparison to neat CaO(cesp). • Best Conversions were achieved with ZnO–CaO(cesp). • Catalyst has shown good reusability up to 4 cycles without significant loss in its activity. - Abstract: Solid base heterogeneous catalysts are one of the promising materials for the transesterification of vegetable oils because these catalysts are generally more reactive than solid acid catalysts which require very severe operating conditions. Calcium oxide has shown good catalytic activity due to its high basicity which is required for transesterification of triacylglycerides (TAGs). In the present study, the transesterification of non-edible, high free fatty acid containing Jatropha and Karanja oils was studied by using waste chicken egg shell derived calcium (i.e. CaO(cesp)) based mixed metal oxides (M-CaO; M = ZnO, MnO2, Fe2O3 and Al2O3) as heterogeneous catalyst. A comparison was also made on the catalytic performance of these prepared catalysts. The catalyst characterizations were done by XRD, SEM, TGA, FT-IR and BET techniques. The effectiveness of the catalysts was highly influenced by the calcination temperature. ZnO–CaO(cesp) catalyst was found to be the most efficient catalyst among all. The maximum conversion for the transesterification of Jatropha and Karanja oils were achieved using 5 wt% catalyst, 65 °C temperature and 12:1 methanol/oil ratio. The catalyst could be re-used effectively during four cycles. Use of the CaO(cesp) based mixed oxides made the process more environmental benign and economical. The biodiesel prepared has shown good fuel characteristics as per EN, ASTM and IS standards

  1. Integration of calcium and chemical looping combustion using composite CaO/CuO-based materials.

    Science.gov (United States)

    Manovic, Vasilije; Anthony, Edward J

    2011-12-15

    Calcium looping cycles (CaL) and chemical looping combustion (CLC) are two new, developing technologies for reduction of CO(2) emissions from plants using fossil fuels for energy production, which are being intensively examined. Calcium looping is a two-stage process, which includes oxy-fuel combustion for sorbent regeneration, i.e., generation of a concentrated CO(2) stream. This paper discuss the development of composite materials which can use copper(II)-oxide (CuO) as an oxygen carrier to provide oxygen for the sorbent regeneration stage of calcium looping. In other words, the work presented here involves integration of calcium looping and chemical looping into a new class of postcombustion CO(2) capture processes designated as integrated CaL and CLC (CaL-CLC or Ca-Cu looping cycles) using composite pellets containing lime (CaO) and CuO together with the addition of calcium aluminate cement as a binder. Their activity was tested in a thermogravimetric analyzer (TGA) during calcination/reduction/oxidation/carbonation cycles. The calcination/reduction typically was performed in methane (CH(4)), and the oxidation/carbonation stage was carried out using a gas mixture containing both CO(2) and O(2). It was confirmed that the material synthesized is suitable for the proposed cycles; with the very favorable finding that reduction/oxidation of the oxygen carrier is complete. Various schemes for the Ca-Cu looping process have been explored here that would be compatible with these new composite materials, along with some different possibilities for flow directions among carbonator, calciner, and air reactor. PMID:22022778

  2. Reduction of chromium oxides with calcium carbide during thestainless steelmaking process

    Directory of Open Access Journals (Sweden)

    B. Arh

    2015-04-01

    Full Text Available An efficient reduction of chromium from slag requires an appropriate reduction agent for the given steelmaking technology. The usual slag reduction praxis consists of carbon injections and additions of ferrosilicon and aluminum.Reduction of chromium containing slags with calcium carbide is an appealing alternative. Calcium carbide is a strong reduction agent that unlike ferrosilicon and aluminum also provides the possibility of foaming slag formation.Experimental work regarding chromium slag reduction with calcium carbide towards usual slag reduction praxis is described in this work. The results show that higher reduction rates in the stage of refining period of the melt and higher level of overall chromium reduction from slag can be reached with the blowing of CaC2.

  3. Calcium-borosilicate glass-ceramics wasteforms to immobilize rare-earth oxide wastes from pyro-processing

    Science.gov (United States)

    Kim, Miae; Heo, Jong

    2015-12-01

    Glass-ceramics containing calcium neodymium(cerium) oxide silicate [Ca2Nd8-xCex(SiO4)6O2] crystals were fabricated for the immobilization of radioactive wastes that contain large portions of rare-earth ions. Controlled crystallization of alkali borosilicate glasses by heating at T ≥ 750 °C for 3 h formed hexagonal Ca-silicate crystals. Maximum lanthanide oxide waste loading was >26.8 wt.%. Ce and Nd ions were highly partitioned inside Ca-silicate crystals compared to the glass matrix; the rare-earth wastes are efficiently immobilized inside the crystalline phases. The concentrations of Ce and Nd ions released in a material characterization center-type 1 test were below the detection limit (0.1 ppb) of inductively coupled plasma mass spectroscopy. Normalized release values performed by a product consistency test were 2.64·10-6 g m-2 for Ce ion and 2.19·10-6 g m-2 for Nd ion. Results suggest that glass-ceramics containing calcium neodymium(cerium) silicate crystals are good candidate wasteforms for immobilization of lanthanide wastes generated by pyro-processing.

  4. Improved cycling performance of P2-type layered sodium cobalt oxide by calcium substitution

    Science.gov (United States)

    Matsui, Masaki; Mizukoshi, Fumikazu; Imanishi, Nobuyuki

    2015-04-01

    P2-type Na2/3-xCaxCoO2 is synthesized via a conventional solid-state reaction. The substituted calcium ions occupy the sodium ion layer and eliminate the lattice mismatches of the two phases in Na2/3-xCaxCoO2. Several voltage steps typically observed in the voltage profiles of NaxCoO2 are mostly disappeared associated with the expansion of single-phase regions, because the substituted calcium ions hinder the ordering of sodium ions and vacancies. Furthermore the Na2/3-xCaxCoO2 shows improved cycling performance especially at high charging-discharging rate. During the cycling test, the calcium-free Na0.74CoO2 shows phase separation to form an inactive sodium poor phase, while the Na5/8Ca1/24CoO2 maintained the single phase, suggesting that the calcium substitution suppress the structural change of the P2-type NaxCoO2 to prevent the phase separation, resulting in the improved cycling performance.

  5. Cheap carbon sorbents produced from lignite by catalytic pyrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Kuznetsov, B.N.; Schchipko, M.L. [Inst. of Chemistry of Natural Organic Materials, Akademgorodok, Krasnoyarsk (Russian Federation)

    1995-12-01

    Some data are presented describing the new technology of carbon sorbent production from powdered lignite in the installation with fluidized bed of catalyst. It was shown the different types of char products with extended pore structure and high sorption ability can be produced from cheap and accessible lignite of Kansk-Achinsk coal pit in pilot installation with fluidized bed of Al-Cu-Cr oxide catalyst or catalytically active slag materials. In comparison with the conventional technologies of pyrolysis the catalytic pyrolysis allows to increase by 3-5 times the process productivity and to decrease significantly the formation of harmful compounds. The latter is accomplished by complete oxidation of gaseous pyrolysis products in the presence of catalysts and by avoiding the formation of pyrolysis tars - the source of cancerogenic compounds. The technology of cheap powdered sorbent production from lignites makes possible to obtain from lignite during the time of pyrolysis only a few seconds char products with porosity up to 0.6 cm{sup 3} /g, and specific surface area more than 400 m{sup 3} /g. Some methods of powdered chars molding into carbon materials with the different shape were proved for producing of firmness sorbents. Cheap carbon sorbents obtained by thermocatalytic pyrolysis can be successfully used in purification of different industrial pollutants as one-time sorbent or as adsorbents of long-term application with periodic regeneration.

  6. Chronic deficit in nitric oxide elicits oxidative stress and augments T-type calcium-channel contribution to vascular tone of rodent arteries and arterioles

    DEFF Research Database (Denmark)

    Howitt, Lauren; Kuo, Ivana Y; Ellis, Anthie;

    2013-01-01

    /L) significantly increased the T-type, but not the L-type, channel contribution to vascular tone in vitro and in vivo, and altered the smooth muscle expression of the Cav3.1 and Cav3.2 T-type channels. In pressurized mesenteric arteries of Cav3.1ko and Cav3.2ko mice, acutely treated with l-NAME, the contribution...... of T-type channels relative to L-type channels was significantly reduced, compared with arteries from wild-type mice.Chronic l-NAME treatment (40 mg/kg/day; 14-18 days) increased blood pressure, vascular superoxide, and the contribution of T-type channels to vascular tone in vivo. The latter was......, by regulating the bioavailability of reactive oxygen species produced by NADPH oxidase. Our data provide evidence for a novel causal link between nitric oxide deficit, oxidative stress, and T-type calcium channel function....

  7. Anionic sorbents for arsenic and technetium species

    International Nuclear Information System (INIS)

    Two sorbents, zirconium coated zeolite and magnesium hydroxide, were tested for their effectiveness in removing arsenic from Albuquerque municipal water. Results for the zirconium coated zeolite indicate that phosphate present in the water interfered with the sorption of arsenic. Additionally, there was a large quantity of iron and copper present in the water, corrosion products from the piping system, which may have interfered with the uptake of arsenic by the sorbent. Magnesium hydroxide has also been proven to be a strong sorbent for arsenic as well as other metals. Carbonate, present in water, has been shown to interfere with the sorption of arsenic by reacting with the magnesium hydroxide to form magnesium carbonate. The reaction mechanism was investigated by FT-IR and shows that hydrogen bonding between an oxygen on the arsenic species and a hydrogen on the Mg(OH)2 is most likely the mechanism of sorption. This was also confirmed by RAMAN spectroscopy and XRD. Technetium exists in multiple oxidation states (IV and VII) and is easily oxidized from the relatively insoluble Tc(IV) form to the highly water soluble and mobile Tc(VII) form. The two oxidation states exhibit different sorption characteristics. Tc(VII) does not sorb to most materials whereas Tc(IV) will strongly sorb to many materials. Therefore, it was determined that it is necessary to first reduce the Tc (using SnCl2) before sorption to stabilize Tc in the environment. Additionally, the effect of carbonate and phosphate on the sorption of technetium by hydroxyapatite was studied and indicated that both have a significant effect on reducing Tc sorption

  8. Desulfurization of indigenous coal with sorbent injection

    International Nuclear Information System (INIS)

    Desulfurization of Lakhra Coal with sorbent injection was carried out in furnace. Limestone and lime was used as sorbent and sorbent/sulphur ratio was varied. The sorbent/sulphur ratio was varied from 0.5 to 5 and size of sorbent from 80 mesh to 325 mesh. Surface capture observed was higher for CaO than CaCO/sub 3/. The %age removal increased as sorbent/sulphur ratio was increased and the finer size also gave increased removal of sulphur, which was due to greater active sites presents in finer size of sorbent. (author)

  9. Comparative study on the change in index of refraction in ion-exchange interdiffusion in alkali-silicate glasses containing calcium, strontium, barium and titanium oxides

    International Nuclear Information System (INIS)

    Different ability to ion exchange from the salts of lithium-sodium-silicate glass melt containing calcium (or strontium, or barium) and titanium oxides in addition has been shown. CaO, SrO and BaO have negative effect, but TiO2 -positive one on the fullness of ion exchange of lithium-sodium and on the rate of interdiffusion in alkali-silicate glass. The value of change in index of refraction of glass with TiO2 is twice higher than glass with calcium oxide (or strontium, or barium) as the fourth component

  10. Transesterification of Jatropha curcas crude oil to biodiesel on calcium lanthanum mixed oxide catalyst: Effect of stoichiometric composition

    International Nuclear Information System (INIS)

    Highlights: • Biodiesel synthesis from Jatropha curcas oil catalyzed by CaO–La2O3 mixed oxide. • Effects of Ca-to-La ratio, catalyst concentration, methanol/oil ratio and reaction temperature were optimized. • Biodiesel yield >85% was achieved at 65 °C temperature. • CaO–La2O3 catalyst can be easy regenerated. - Abstract: Heterogeneous solid mixed oxide (CaO–La2O3) catalysts with different molar ratios of calcium to lanthanum (Ca-to-La) were synthesized by co-precipitation method. The synthesized solid CaO–La2O3 mixed metal oxide catalysts were utilized in transesterification of Jatropha curcus oil as feedstock to produce biodiesel. Under the optimized conditions at 65 °C, 4% catalyst dose with 24:1 MeOH to Jatropha oil molar ratio, the transesterification reaction exhibited 86.51% of biodiesel yield. The prepared catalysts were characterized using various techniques such as X-ray diffraction (XRD), nitrogen sorption with Brunauer–Emmer–Teller (BET) method, temperature-programmed desorption of CO2 (CO2-TPD) and scanning electron microscopy (SEM). Influence of Ca-to-La atomic ratio in the mixed metal oxide catalyst, catalyst amount, methanol to oil molar ratio, reaction time, different oils on the fatty acid methyl ester (FAME) yield were appraised. Different catalyst regeneration procedures were also performed to investigate the reusability of the CaO–La2O3 catalyst

  11. Micro-arc oxidation as a tool to develop multifunctional calcium-rich surfaces for dental implant applications

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, A.R., E-mail: arribeiro@inmetro.gov.br [Department of Periodontology, Araraquara Dental School, University Estadual Paulista, Rua Humaitá 1680, 14801-903 Araraquara, São Paulo (Brazil); Directory of Metrology Applied to Life Science, National Institute of Metrology Quality and Technology, Av. N. S. das Graças 50, Xerém, Duque de Caxias, Rio de Janeiro (Brazil); Brazilian Branch of Institute of Biomaterials, Tribocorrosion and Nanomedicine (IBTN/Br) (Brazil); Oliveira, F., E-mail: fernando@dem.uminho.pt [Brazilian Branch of Institute of Biomaterials, Tribocorrosion and Nanomedicine (IBTN/Br) (Brazil); Centre for Mechanical and Materials Technologies, University of Minho, Campus de Azurém, 4800-058 Guimarães (Portugal); Boldrini, L.C., E-mail: lcboldrini@inmetro.gov.br [Directory of Metrology Applied to Life Science, National Institute of Metrology Quality and Technology, Av. N. S. das Graças 50, Xerém, Duque de Caxias, Rio de Janeiro (Brazil); Leite, P.E., E-mail: leitepec@gmail.com [Directory of Metrology Applied to Life Science, National Institute of Metrology Quality and Technology, Av. N. S. das Graças 50, Xerém, Duque de Caxias, Rio de Janeiro (Brazil); Falagan-Lotsch, P., E-mail: prifalagan@gmail.com [Directory of Metrology Applied to Life Science, National Institute of Metrology Quality and Technology, Av. N. S. das Graças 50, Xerém, Duque de Caxias, Rio de Janeiro (Brazil); Linhares, A.B.R., E-mail: adrianalinhares@hotmail.com [Clinical Research Unit, Antonio Pedro Hospital, Fluminense Federal University, Niterói (Brazil); and others

    2015-09-01

    Titanium (Ti) is commonly used in dental implant applications. Surface modification strategies are being followed in last years in order to build Ti oxide-based surfaces that can fulfill, simultaneously, the following requirements: induced cell attachment and adhesion, while providing a superior corrosion and tribocorrosion performance. In this work micro-arc oxidation (MAO) was used as a tool for the growth of a nanostructured bioactive titanium oxide layer aimed to enhance cell attachment and adhesion for dental implant applications. Characterization of the surfaces was performed, in terms of morphology, topography, chemical composition and crystalline structure. Primary human osteoblast adhesion on the developed surfaces was investigated in detail by electronic and atomic force microscopy as well as immunocytochemistry. Also an investigation on the early cytokine production was performed. Results show that a relatively thick hybrid and graded oxide layer was produced on the Ti surface, being constituted by a mixture of anatase, rutile and amorphous phases where calcium (Ca) and phosphorous (P) were incorporated. An outermost nanometric-thick amorphous oxide layer rich in Ca was present in the film. This amorphous layer, rich in Ca, improved fibroblast viability and metabolic activity as well as osteoblast adhesion. High-resolution techniques allowed to understand that osteoblasts adhered less in the crystalline-rich regions while they preferentially adhere and spread over in the Ca-rich amorphous oxide layer. Also, these surfaces induce higher amounts of IFN-γ cytokine secretion, which is known to regulate inflammatory responses, bone microarchitecture as well as cytoskeleton reorganization and cellular spreading. These surfaces are promising in the context of dental implants, since they might lead to faster osseointegration. - Highlights: • A nanometric-structured calcium-rich amorphous layer with improved bioactivity was produced on titanium surfaces.

  12. Micro-arc oxidation as a tool to develop multifunctional calcium-rich surfaces for dental implant applications

    International Nuclear Information System (INIS)

    Titanium (Ti) is commonly used in dental implant applications. Surface modification strategies are being followed in last years in order to build Ti oxide-based surfaces that can fulfill, simultaneously, the following requirements: induced cell attachment and adhesion, while providing a superior corrosion and tribocorrosion performance. In this work micro-arc oxidation (MAO) was used as a tool for the growth of a nanostructured bioactive titanium oxide layer aimed to enhance cell attachment and adhesion for dental implant applications. Characterization of the surfaces was performed, in terms of morphology, topography, chemical composition and crystalline structure. Primary human osteoblast adhesion on the developed surfaces was investigated in detail by electronic and atomic force microscopy as well as immunocytochemistry. Also an investigation on the early cytokine production was performed. Results show that a relatively thick hybrid and graded oxide layer was produced on the Ti surface, being constituted by a mixture of anatase, rutile and amorphous phases where calcium (Ca) and phosphorous (P) were incorporated. An outermost nanometric-thick amorphous oxide layer rich in Ca was present in the film. This amorphous layer, rich in Ca, improved fibroblast viability and metabolic activity as well as osteoblast adhesion. High-resolution techniques allowed to understand that osteoblasts adhered less in the crystalline-rich regions while they preferentially adhere and spread over in the Ca-rich amorphous oxide layer. Also, these surfaces induce higher amounts of IFN-γ cytokine secretion, which is known to regulate inflammatory responses, bone microarchitecture as well as cytoskeleton reorganization and cellular spreading. These surfaces are promising in the context of dental implants, since they might lead to faster osseointegration. - Highlights: • A nanometric-structured calcium-rich amorphous layer with improved bioactivity was produced on titanium surfaces.

  13. Oxidized Low-density Lipoprotein (ox-LDL) Cholesterol Induces the Expression of miRNA-223 and L-type Calcium Channel Protein in Atrial Fibrillation.

    Science.gov (United States)

    He, Fengping; Xu, Xin; Yuan, Shuguo; Tan, Liangqiu; Gao, Lingjun; Ma, Shaochun; Zhang, Shebin; Ma, Zhanzhong; Jiang, Wei; Liu, Fenglian; Chen, Baofeng; Zhang, Beibei; Pang, Jungang; Huang, Xiuyan; Weng, Jiaqiang

    2016-01-01

    Atrial fibrillation (AF) is the most common sustained arrhythmia causing high morbidity and mortality. While changing of the cellular calcium homeostasis plays a critical role in AF, the L-type calcium channel α1c protein has suggested as an important regulator of reentrant spiral dynamics and is a major component of AF-related electrical remodeling. Our computational modeling predicted that miRNA-223 may regulate the CACNA1C gene which encodes the cardiac L-type calcium channel α1c subunit. We found that oxidized low-density lipoprotein (ox-LDL) cholesterol significantly up-regulates both the expression of miRNA-223 and L-type calcium channel protein. In contrast, knockdown of miRNA-223 reduced L-type calcium channel protein expression, while genetic knockdown of endogenous miRNA-223 dampened AF vulnerability. Transfection of miRNA-223 by adenovirus-mediated expression enhanced L-type calcium currents and promoted AF in mice while co-injection of a CACNA1C-specific miR-mimic counteracted the effect. Taken together, ox-LDL, as a known factor in AF-associated remodeling, positively regulates miRNA-223 transcription and L-type calcium channel protein expression. Our results implicate a new molecular mechanism for AF in which miRNA-223 can be used as an biomarker of AF rheumatic heart disease. PMID:27488468

  14. Oxidized Low-density Lipoprotein (ox-LDL) Cholesterol Induces the Expression of miRNA-223 and L-type Calcium Channel Protein in Atrial Fibrillation

    Science.gov (United States)

    He, Fengping; Xu, Xin; Yuan, Shuguo; Tan, Liangqiu; Gao, Lingjun; Ma, Shaochun; Zhang, Shebin; Ma, Zhanzhong; Jiang, Wei; Liu, Fenglian; Chen, Baofeng; Zhang, Beibei; Pang, Jungang; Huang, Xiuyan; Weng, Jiaqiang

    2016-08-01

    Atrial fibrillation (AF) is the most common sustained arrhythmia causing high morbidity and mortality. While changing of the cellular calcium homeostasis plays a critical role in AF, the L-type calcium channel α1c protein has suggested as an important regulator of reentrant spiral dynamics and is a major component of AF-related electrical remodeling. Our computational modeling predicted that miRNA-223 may regulate the CACNA1C gene which encodes the cardiac L-type calcium channel α1c subunit. We found that oxidized low-density lipoprotein (ox-LDL) cholesterol significantly up-regulates both the expression of miRNA-223 and L-type calcium channel protein. In contrast, knockdown of miRNA-223 reduced L-type calcium channel protein expression, while genetic knockdown of endogenous miRNA-223 dampened AF vulnerability. Transfection of miRNA-223 by adenovirus-mediated expression enhanced L-type calcium currents and promoted AF in mice while co-injection of a CACNA1C-specific miR-mimic counteracted the effect. Taken together, ox-LDL, as a known factor in AF-associated remodeling, positively regulates miRNA-223 transcription and L-type calcium channel protein expression. Our results implicate a new molecular mechanism for AF in which miRNA-223 can be used as an biomarker of AF rheumatic heart disease.

  15. High-temperature CO2 capture cycles of hydrated limestone prepared with aluminum (hydr)oxides derived from kaolin

    International Nuclear Information System (INIS)

    Highlights: • Hydrated limestone exhibited a higher reactivity and stability. • Microstructure of hydrated limestone was significantly improved. • Hydrated limestone still suffered less loss-incapacity. • Hydrated limestone sorbents with kaolin-based binders were prepared and characterized. • Sorbents prepared from hydrated limestone and Al(OH)3 binder are a promising sorbent. - Abstract: A simple and convenient process was used to improve the utilization of natural limestone and kaolin for calcium looping technology and environmental applications. The calcined natural limestone modified with the distilled water (denoted as Limestone-W), was systematically studied and compared with the other CaO sorbents (calcium acetate, calcium D-gluconate and calcined natural limestone). These CaO-based sorbents were tested for their CO2 capture behavior through 20 carbonation/calcination cycles in a thermo-gravimetric analyzer (TGA). Their morphology, pore structure and phase composition before and after carbonation/calcination cycles were determined by scanning electron microscopy, nitrogen adsorption, and X-ray diffraction. The first-cycle and multicycle sorption results revealed that the Limestone-W sorbent exhibited a relatively faster reaction rate and higher cyclic CO2 capture. The characterization data indicated that the Limestone-W was composed of a special calcium oxide structure with lower crystalline and higher porosity nanoparticles, which appeared to be the main reasons for its higher CO2 capture capability. However, the Limestone-W still suffered loss of reactivity, even though it was less pronounced than the other CaO sorbent. To avoid this unfavorable effect, a thermally stable inert material (aluminum hydroxide derived from kaolin) was incorporated into the Limestone-W structure. This new sorbent revealed higher stability because the formation of a stable framework of Ca12Al14O33 particles hindered densification and sintering of the CaO phase. It was

  16. FAME Production from Jatropha curcas Seed Oil via Calcium Oxide Catalyzed Transesterification and its Purification using Acid Activated Bentonite

    Directory of Open Access Journals (Sweden)

    Novizar Nazir

    2013-01-01

    Full Text Available This paper presents the study of transesterification of Jatropha curcas oil (JCO via environmentally benign process using calcium oxide as heterogeneous catalyst.  Response surface methodology (RSM based on central composite design (CCD was performed to optimize three reaction variables in this study.  The transesterification process variables were reaction time, x1 (60 minutes-120 minutes,   molar ratio of methanol: oil, x2 (5:1 – 13:1, and amount of catalyst,  x3 (0.5 % –1.50 % of mass fraction.  Since water washing method is not suitable to purify CaO synthesized fatty acid methyl esters (FAME,   the purification of as-synthesized FAME with acid-activated bentonites to eliminate the remaining calcium was also investigated.   It was found that the yield of JCO FAME could reach up to 94.35 % using the following reaction conditions: 79.33 minutes reaction time, 10.41:1 methanol:oil molar ratio and 0.99 %  catalyst at reaction temperature 65oC.  Among bentonites used in the purification,   2.5% of H2SO4-activated bentonite shows a good performance as decalcifying agent for FAME purification.  The properties of purified jatropha FAME were comparable to those of diesel and satisfied the international standard.

  17. The Retentive Strength of Cemented Zirconium Oxide Crowns after Dentin Pretreatment with Desensitizing Paste Containing 8% Arginine and Calcium Carbonate.

    Science.gov (United States)

    Pilo, Raphael; Harel, Noga; Nissan, Joseph; Levartovsky, Shifra

    2016-01-01

    The effect of dentin pretreatment with Desensitizing Paste containing 8% arginine and calcium carbonate on the retention of zirconium oxide (Y-TZP) crowns was tested. Forty molar teeth were mounted and prepared using a standardized protocol. Y-TZP crowns were produced using computer-aided design and computer-aided manufacturing (CAD-CAM) technology. The 40 prepared teeth were either pretreated with Desensitizing Paste or not pretreated. After two weeks, each group was subdivided into two groups, cemented with either Resin Modified Glass Ionomer Cement (RMGIC) or Self Adhesive Resin Cement (SARC)). Prior to cementation, the surface areas of the prepared teeth were measured. After aging, the cemented crown-tooth assemblies were tested for retentive strength using a universal testing machine. The debonded surfaces of the teeth and crowns were examined microscopically at 10× magnification. Pretreating the dentin surfaces with Desensitizing Paste prior to cementation did not affect the retention of the Y-TZP crowns. The retentive values for RMGIC (3.04 ± 0.77 MPa) were significantly higher than those for SARC (2.28 ± 0.58 MPa). The predominant failure modes for the RMGIC and SARC were adhesive cement-dentin and adhesive cement-crown, respectively. An 8.0% arginine and calcium carbonate in-office desensitizing paste can be safely used to reduce post-cementation sensitivity without reducing the retentive strength of Y-TZP crowns. PMID:27023532

  18. The Retentive Strength of Cemented Zirconium Oxide Crowns after Dentin Pretreatment with Desensitizing Paste Containing 8% Arginine and Calcium Carbonate

    Directory of Open Access Journals (Sweden)

    Raphael Pilo

    2016-03-01

    Full Text Available The effect of dentin pretreatment with Desensitizing Paste containing 8% arginine and calcium carbonate on the retention of zirconium oxide (Y-TZP crowns was tested. Forty molar teeth were mounted and prepared using a standardized protocol. Y-TZP crowns were produced using computer-aided design and computer-aided manufacturing (CAD-CAM technology. The 40 prepared teeth were either pretreated with Desensitizing Paste or not pretreated. After two weeks, each group was subdivided into two groups, cemented with either Resin Modified Glass Ionomer Cement (RMGIC or Self Adhesive Resin Cement (SARC. Prior to cementation, the surface areas of the prepared teeth were measured. After aging, the cemented crown-tooth assemblies were tested for retentive strength using a universal testing machine. The debonded surfaces of the teeth and crowns were examined microscopically at 10× magnification. Pretreating the dentin surfaces with Desensitizing Paste prior to cementation did not affect the retention of the Y-TZP crowns. The retentive values for RMGIC (3.04 ± 0.77 MPa were significantly higher than those for SARC (2.28 ± 0.58 MPa. The predominant failure modes for the RMGIC and SARC were adhesive cement-dentin and adhesive cement-crown, respectively. An 8.0% arginine and calcium carbonate in-office desensitizing paste can be safely used to reduce post-cementation sensitivity without reducing the retentive strength of Y-TZP crowns.

  19. Productive performance and efficiency of utilization of the diet components in dairy cows fed castor meal treated with calcium oxide

    Directory of Open Access Journals (Sweden)

    Juliana Variz Cobianchi

    2012-10-01

    Full Text Available The effect of replacing of 0; 0.33; 0.67 and 1.0 (kg/kg of soybean meal (SBM by undecorticated castor seed meal treated with calcium oxide (CMT - 60 g/kg was evaluated on performance and efficiency of nutrient utilization in dairy cows. Sixteen Holstein and crossbred cows were distributed in four 4 × 4 latin squares. Animals received concentrated feed at a ratio of 1 kg for 3 kg of milk produced, in the natural matter. The diets had the same amount of nitrogen (150.4 g crude protein/kg DM, containing 325.6 g of concentrated feed/kg DM. There was no effect on the serum concentration of transaminase and the animals showed no clinical symptoms of intoxication by ricin. The intake of DM, crude protein (CP and non-fibrous carbohydrates (NFC reduced from 0.67 replacement of SBM by CMT. The intake of neutral detergent fibers corrected for ash and protein (NDFap increased from 0.33 replacement of SBM with CMT. Although the digestibility of dietary components decreased from 0.33 replacement, the intake of digestible components only reduced from 0.67 replacement. Because of the reduction of digestible energy, the synthesis of microbial CP and the utilization efficiency of rumen-degradable protein for the synthesis of microbial CP reduced with full replacement of SBM by CMT. Milk yield, milk composition, daily variation of body weight and the efficiency of utilization of the nutrients for the synthesis of N in milk reduced from 0.67 replacement of SBM by CMT. Castor seed meal treated with calcium oxide can replace up to 0.33 of SBM (50 g/kg DM diet DM in the diet of dairy cows with an average milk production of 20 kg/day.

  20. The hygroscopic properties of spray dryer sorbents with select additives

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, C.S.; Rood, M.J. (Illinois Univ., Urbana, IL (USA))

    1988-01-01

    The use of spray dryers to separate and remove SO{sub 2} and HCl gases from emissions generated by the combustion of low sulfur coal and municipal solid waste is becoming a widely accepted practice. Advantages of spray drying compared to wet scrubbing include lower capital costs, reduction in corrosion and scaling problems, elimination of a wet sludge by-product, and better reliability. Some of the disadvantages include higher sorbent costs, potential blinding of the particle control device that is downstream of the spray dryer, and low NO{sub x} collection efficiencies. Because of the spray dryer's inherent advantages, it would be useful to improve the spray dryer's ability to simultaneously remove SO{sub 2}, NO{sub x}, and HCl from flue gases while using a low cost sorbent. Results of the effort to develop a spray dryer with these capabilities is presented in this paper. Preliminary research on the use of inorganic additives to enhance the SO{sub 2} collection efficiency of spray dryers has already been performed by other researchers. However, further research pertaining to the fundamental aspects of the use of additives would be useful to describe how inorganic additives enhance the reactivity of potential spray dryer sorbents with SO{sub 2}, NO{sub x}, and HCl. This investigation focuses on the use of additives to increase the amount of H{sub 2}O adsorbed by select sorbents and to increase the chemical reactivity of the sorbent. Several inorganic deliquescent salts and oxidants were selected as additives because of their potential ability to increase the amount of liquid H{sub 2}O associated with the sorbents and to enhance the rate of oxidation of SO{sub 2} and NO{sub x} in the liquid phase.

  1. Lipid oxidation in fish oil enriched mayonnaise : Calcium disodium ethylenediaminetetraacetate, but not gallic acid, strongly inhibited oxidative deterioration

    DEFF Research Database (Denmark)

    Jacobsen, Charlotte; Hartvigsen, Karsten; Thomsen, Mikael Holm;

    2001-01-01

    attributed to its ability to chelate free metal ions and iron from egg yolk located at the oil-water interface. Gallic acid reduced the levels of both free radicals and lipid hydroperoxides but promoted slightly the oxidative flavor deterioration in mayonnaise and influenced the profile of volatiles. Gallic......The antioxidative effects of gallic acid, EDTA, and extra emulsifier Panodan DATEM TR in mayonnaise enriched with 16% fish oil were investigated. EDTA reduced the formation of free radicals, lipid hydroperoxides, volatiles, and fishy and rancid off-flavors. The antioxidative effect of EDTA was...... acid may therefore promote the decomposition of lipid hydroperoxides to volatile oxidation products. Addition of extra emulsifier reduced the lipid hydroperoxide levels but did not influence the level of free radicals or the oxidative flavor deterioration in mayonnaisse; however, it appeared to alter...

  2. Novel sorbents for environmental remediation

    Science.gov (United States)

    Manariotis, Ioannis D.; Karapanagioti, Hrissi K.; Werner, David

    2014-05-01

    Nowadays, one of the major environmental problems is the pollution of aquatic systems and soil by persistent pollutants. Persistent pollutants have been found widespread in sediments, surface waters, and drinking water supplies. The removal of pollutants can be accomplished prior to their discharge to receiving bodies or by immobilizing them onto soil. Sorption is the most commonly applied process, and activated carbons have been widely used. Rapid progress in nanotechnology and a new focus on biomass-based instead of non-renewable starting materials have produced a wide range of novel engineered sorbents including biosorbents, biochars, carbon-based nanoparticles, bio-nano hybrid materials, and iron-impregnated activated carbons. Sorbent materials have been used in environmental remediation processes and especially in agricultural soil, sediments and contaminated soil, water treatment, and industrial wastewater treatment. Furthermore, sorbents may enhance the synergistic action of other processes, such as volatilization and biodegradation. Novel sorbents have been employed for the removal or immobilization of persistent pollutants such as and include heavy metals (As, Cr, Cu, Pb, Cd, and Hg), halogenated organic compounds, endocrine disrupting chemicals, metalloids and non-metallic elements, and other organic pollutants. The development and evaluation of novel sorbents requires a multidisciplinary approach encompassing environmental, nanotechnology, physical, analytical, and surface chemistry. The necessary evaluations encompass not only the efficiency of these materials to remove pollutants from surface waters and groundwater, industrial wastewater, polluted soils and sediments, etc., but also the potential side-effects of their environmental applications. The aim of this work is to present the results of the use of biochar and impregnated carbon sorbents for the removal of organic pollutants and metals. Furthermore, the new findings from the forthcoming session

  3. Development of new sorbents to remove mercury and selenium from flue gas. Final report, September 1, 1993--August 31, 1994

    Energy Technology Data Exchange (ETDEWEB)

    Shiao, S.Y. [Babcock and Wilcox Co., Alliance, OH (United States)

    1995-02-01

    Mercury (Hg) and selenium (Se) are two of the volatile trace metals in coal, which are often not captured by conventional gas clean up devices of coal-fired boilers. An alternative is to use sorbents to capture the volatile components of trace metals after coal combustion. In this project sorbent screening tests were performed in which ten sorbents were selected to remove metallic mercury in N{sub 2}. These sorbents included activated carbon, char prepared from Ohio No. 5 coal, molecular sieves, silica gel, aluminum oxide, hydrated lime, Wyoming bentonite, kaolin, and Amberite IR-120 (an ion-exchanger). The sorbents were selected based on published information and B&W`s experience on mercury removal. The promising sorbent was then selected and modified for detailed studies of removal of mercury and selenium compounds. The sorbents were tested in a bench-scale adsorption facility. A known amount of each sorbent was loaded in the column as a packed bed. A carrier gas was bubbled through the mercury and selenium compounds. The vaporized species were carried by the gas and went through the sorbent beds. The amount of mercury and selenium compounds captured by the sorbents was determined by atomic absorption. Results are discussed.

  4. Carrageenan-grafted magnetite nanoparticles as recyclable sorbents for dye removal

    Energy Technology Data Exchange (ETDEWEB)

    Daniel-da-Silva, Ana L., E-mail: ana.luisa@ua.pt; Salgueiro, Ana M., E-mail: a38242@ua.pt; Creaney, Bianca, E-mail: bianca.creaney@gmail.com; Oliveira-Silva, Rui, E-mail: ruipedro.silva@ua.pt [University of Aveiro, Department of Chemistry, CICECO, Aveiro Institute of Materials (Portugal); Silva, Nuno J. O., E-mail: nunojoao@ua.pt [University of Aveiro, Department of Physics, CICECO, Aveiro Institute of Materials (Portugal); Trindade, Tito, E-mail: tito@ua.pt [University of Aveiro, Department of Chemistry, CICECO, Aveiro Institute of Materials (Portugal)

    2015-07-15

    The efforts dedicated to improving water decontamination procedures have prompted the interest in the development of efficient, inexpensive, and reusable sorbents for the uptake of dye pollutants. In this work, novel sorbents consisting of carrageenan polysaccharides grafted to magnetic iron oxide nanoparticles were prepared. κ- and ι-carrageenan were first chemically modified by carboxymethylation and then covalently attached via amide bond to the surface of aminated silica-coated magnetite nanoparticles, both steps monitored using infrared spectroscopy (FTIR) analysis. The kinetics and the equilibrium behavior of the cationic dye methylene blue (MB) adsorption onto the carrageenan sorbents were investigated. ι-carrageenan sorbents displayed higher MB adsorption capacity that was ascribed to high content of sulfonate groups. Overall, the pseudo-second order equation provided a good description of the adsorption kinetics. The κ-carrageenan sorbents followed an unusual Z-type equilibrium adsorption isotherm whereas the isotherm of ι-carrageenan sorbents, although displaying a conventional shape, could not be successfully predicted by isotherm models commonly used. Noteworthy, both sorbents were long-term stable and could easily be recycled by simply rinsing with KCl aqueous solution. The removal efficiency of κ-carrageenan sorbents was 92 % in the first adsorption cycle and kept high (>80 %) even after six consecutive adsorption/desorption cycles.

  5. Carrageenan-grafted magnetite nanoparticles as recyclable sorbents for dye removal

    International Nuclear Information System (INIS)

    The efforts dedicated to improving water decontamination procedures have prompted the interest in the development of efficient, inexpensive, and reusable sorbents for the uptake of dye pollutants. In this work, novel sorbents consisting of carrageenan polysaccharides grafted to magnetic iron oxide nanoparticles were prepared. κ- and ι-carrageenan were first chemically modified by carboxymethylation and then covalently attached via amide bond to the surface of aminated silica-coated magnetite nanoparticles, both steps monitored using infrared spectroscopy (FTIR) analysis. The kinetics and the equilibrium behavior of the cationic dye methylene blue (MB) adsorption onto the carrageenan sorbents were investigated. ι-carrageenan sorbents displayed higher MB adsorption capacity that was ascribed to high content of sulfonate groups. Overall, the pseudo-second order equation provided a good description of the adsorption kinetics. The κ-carrageenan sorbents followed an unusual Z-type equilibrium adsorption isotherm whereas the isotherm of ι-carrageenan sorbents, although displaying a conventional shape, could not be successfully predicted by isotherm models commonly used. Noteworthy, both sorbents were long-term stable and could easily be recycled by simply rinsing with KCl aqueous solution. The removal efficiency of κ-carrageenan sorbents was 92 % in the first adsorption cycle and kept high (>80 %) even after six consecutive adsorption/desorption cycles

  6. Calcium oxide/carbon dioxide reactivity in a packed bed reactor of a chemical heat pump for high-temperature gas reactors

    International Nuclear Information System (INIS)

    The thermal performance of a chemical heat pump that uses a calcium oxide/carbon dioxide reaction system was discussed as a heat storage system for utilizing heat output from high temperature gas reactors (HTGR). Calcium oxide/carbon dioxide reactivity for the heat pump was measured using a packed bed reactor containing 1.0 kg of reactant. The reactor was capable of storing heat at 900 deg. C by decarbonation of calcium carbonate and generating up to 997 deg. C by carbonation of calcium oxide. The amount of stored heat in the reactor was 800-900 kJ kg-1. The output temperature of the reactor could be controlled by regulating the carbonation pressure. The thermal storage performance of the reactor was superior to that of conventional sensible heat storage systems. A heat pump using this CaO/CO2 reactor is expected to contribute to thermal load leveling and to realize highly efficient utilization of HTGR output due to the high heat storage density and high-quality temperature output of the heat pump

  7. On the preparation of TiAl alloy by direct reduction of the oxide mixtures in calcium chloride melt

    Energy Technology Data Exchange (ETDEWEB)

    Prabhat K. Tripathy; Derek J. Fray

    2011-11-01

    electrode in a pool of molten calcium chloride at a temperature of 9000C. The dominant mechanism of the oxygen removal was the ionization of oxygen followed by its subsequent discharge, as CO2/CO, at the anode surface. The removal of oxygen from the oxide mixture helped form the alloy in situ. The presentation shall cover the detailed experimental results pertaining to the preparation, evaluation and characterization of Ti-47Al-2Nb-2Cr (atom%) alloy.

  8. 21 CFR 573.240 - Calcium periodate.

    Science.gov (United States)

    2010-04-01

    ... with calcium hydroxide or calcium oxide to form a substance consisting of not less than 60 percent by... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium periodate. 573.240 Section 573.240 Food... Additive Listing § 573.240 Calcium periodate. The food additive calcium periodate may be safely used...

  9. Reducing nitrous oxide emissions by changing N fertiliser use from calcium ammonium nitrate (CAN) to urea based formulations.

    Science.gov (United States)

    Harty, M A; Forrestal, P J; Watson, C J; McGeough, K L; Carolan, R; Elliot, C; Krol, D; Laughlin, R J; Richards, K G; Lanigan, G J

    2016-09-01

    The accelerating use of synthetic nitrogen (N) fertilisers, to meet the world's growing food demand, is the primary driver for increased atmospheric concentrations of nitrous oxide (N2O). The IPCC default emission factor (EF) for N2O from soils is 1% of the N applied, irrespective of its form. However, N2O emissions tend to be higher from nitrate-containing fertilisers e.g. calcium ammonium nitrate (CAN) compared to urea, particularly in regions, which have mild, wet climates and high organic matter soils. Urea can be an inefficient N source due to NH3 volatilisation, but nitrogen stabilisers (urease and nitrification inhibitors) can improve its efficacy. This study evaluated the impact of switching fertiliser formulation from calcium ammonium nitrate (CAN) to urea-based products, as a potential mitigation strategy to reduce N2O emissions at six temperate grassland sites on the island of Ireland. The surface applied formulations included CAN, urea and urea with the urease inhibitor N-(n-butyl) thiophosphoric triamide (NBPT) and/or the nitrification inhibitor dicyandiamide (DCD). Results showed that N2O emissions were significantly affected by fertiliser formulation, soil type and climatic conditions. The direct N2O emission factor (EF) from CAN averaged 1.49% overall sites, but was highly variable, ranging from 0.58% to 3.81. Amending urea with NBPT, to reduce ammonia volatilisation, resulted in an average EF of 0.40% (ranging from 0.21 to 0.69%)-compared to an average EF of 0.25% for urea (ranging from 0.1 to 0.49%), with both fertilisers significantly lower and less variable than CAN. Cumulative N2O emissions from urea amended with both NBPT and DCD were not significantly different from background levels. Switching from CAN to stabilised urea formulations was found to be an effective strategy to reduce N2O emissions, particularly in wet, temperate grassland. PMID:27155080

  10. Effects of temperature on the heterogeneous oxidation of sulfur dioxide by ozone on calcium carbonate

    Directory of Open Access Journals (Sweden)

    L. Y. Wu

    2011-01-01

    Full Text Available The heterogeneous oxidations of sulfur dioxide by ozone on CaCO3 were studied as a function of temperature (230 to 298 K at ambient pressure. Oxidation reactions were followed in real time using diffuse reflectance infrared Fourier transform spectrometry (DRIFTS to obtain kinetics and mechanistic data. From the analysis of the spectral features, the formation of sulfate was identified on the surface in the presence of O3 and SO2 at different temperatures from 230 to 298 K. The results showed that the heterogeneous oxidations and the rate of sulfate formation were sensitive to temperature. An interesting stage-transition state was observed at temperatures range from 230 to 257 K, but it became ambiguous gradually above 257 K. The reactive uptake coefficients at different temperatures from 230 to 298 K were acquired for the first time, which can be used directly in the model studies to predict the formation of secondary sulfate aerosol in the troposphere. Furthermore, the rate of sulfate formation had a turning point at about 250 K. The sulfate concentration at 250 K was about twice as large as that at 298 K. The rate of sulfate formation increased with decreasing temperature at temperatures above 250 K, while there is a contrary temperature effect at temperatures below 250 K. The activation energy for heterogeneous oxidations at temperatures from 245 K to 230 K was determined to be 14.63 ± 0.20 kJ mol−1. Mechanism of temperature dependence was proposed and the atmospheric implications were discussed.

  11. Effects of temperature on the heterogeneous oxidation of sulfur dioxide by ozone on calcium carbonate

    Directory of Open Access Journals (Sweden)

    L. Y. Wu

    2011-07-01

    Full Text Available The heterogeneous oxidation of sulfur dioxide by ozone on CaCO3 was studied as a function of temperature (230 to 298 K at ambient pressure. Oxidation reactions were followed in real time using diffuse reflectance infrared Fourier transform spectrometry (DRIFTS to obtain kinetic and mechanistic data. From the analysis of the spectral features, the formation of sulfate was identified on the surface in the presence of O3 and SO2 at different temperatures from 230 to 298 K. The results showed that the heterogeneous oxidation and the rate of sulfate formation were sensitive to temperature. An interesting stage-transition region was observed at temperatures ranging from 230 to 257 K, but it became ambiguous gradually above 257 K. The reactive uptake coefficients at different temperatures from 230 to 298 K were acquired for the first time, which can be used directly in atmospheric chemistry modeling studies to predict the formation of secondary sulfate aerosol in the troposphere. Furthermore, the rate of sulfate formation had a turning point at about 250 K. The sulfate concentration at 250 K was about twice as large as that at 298 K. The rate of sulfate formation increased with decreasing temperature at temperatures above 250 K, while there is a contrary temperature effect at temperatures below 250 K. The activation energy for heterogeneous oxidation at temperatures from 245 K to 230 K was determined to be 14.63 ± 0.20 kJ mol−1. A mechanism for the temperature dependence was proposed and the atmospheric implications were discussed.

  12. Calcium entry induces mitochondrial oxidant stress in vagal neurons at risk in Parkinson’s disease

    OpenAIRE

    Goldberg, Joshua A.; Guzman, Jaime N.; Estep, Chad M.; Ilijic, Ema; Kondapalli, Jyothisri; Sanchez-Padilla, Javier; Surmeier, D. James

    2012-01-01

    Mitochondrial oxidant stress is widely viewed as critical to pathogenesis in Parkinson’s disease. But the origins of this stress are poorly defined. One possibility is that it arises from the metabolic demands associated with regenerative activity. To test this hypothesis, neurons in the dorsal motor nucleus of the vagus (DMV), a population cholinergic neurons that shows signs of pathology in the early stages of Parkinson’s disease, were characterized in mouse brain slices. DMV neurons were s...

  13. Economic Evaluation for the Production of Sorbents and Catalysts Derived from Hydrous Titanium Oxide Microspheres Prepared by the HMTA Internal Gelation Process

    International Nuclear Information System (INIS)

    Hydrous metal oxides of Zr, Ti, Hf, Fe, Al, etc. are inorganic ion exchangers that have high selectivities and efficiencies for separating and removing fission products, actinides, and other undesirable elements from aqueous waste streams. In most cases, these ion exchangers are commercially available only as fine powders or as unstable granular particles that are not readily adaptable to continuous processing techniques such as column chromatography. Hydrous metal oxides can be prepared as microspheres by the internal gelation process. This process is unique in that it provides a means of making a usable engineered form of inorganic ion exchanger that can be used in large-scale column separations. With such material, the flow dynamics in column operations would be greatly enhanced. In addition, the microspheres are in a stable form that has little or no tendency to degrade under dynamic conditions. Another advantage of the process is that the gelation time and size of the microspheres can be controlled. Also, microspheres can be reproducibly prepared on either a small or a large scale-which is not always true for batch preparation of the powdered or granular forms. The use of these materials can be expanded in a number of ways. The process allows for the microspheres to be homogeneously embedded with fine particles of other selective ion exchangers, and for the microspheres (undried) to be chemically converted to microspheres of other ion-exchanger materials such as phosphates, silicophosphates, hexacyanoferrates, tungstates, and molybdates. This report presents an economic evaluation of the preparation of hydrous titanium oxide (HTiO) microspheres by an internal gelation process for use in making ion exchangers, catalysts, and getters. It also examines the estimated costs for a company to produce the material but does not discuss the price to be charged since that value would take into account company policy-matters that cannot be covered here. Since the volume

  14. Performance and economic assessments of a solid oxide fuel cell system with a two-step ethanol-steam-reforming process using CaO sorbent

    Science.gov (United States)

    Tippawan, Phanicha; Arpornwichanop, Amornchai

    2016-02-01

    The hydrogen production process is known to be important to a fuel cell system. In this study, a carbon-free hydrogen production process is proposed by using a two-step ethanol-steam-reforming procedure, which consists of ethanol dehydrogenation and steam reforming, as a fuel processor in the solid oxide fuel cell (SOFC) system. An addition of CaO in the reformer for CO2 capture is also considered to enhance the hydrogen production. The performance of the SOFC system is analyzed under thermally self-sufficient conditions in terms of the technical and economic aspects. The simulation results show that the two-step reforming process can be run in the operating window without carbon formation. The addition of CaO in the steam reformer, which runs at a steam-to-ethanol ratio of 5, temperature of 900 K and atmospheric pressure, minimizes the presence of CO2; 93% CO2 is removed from the steam-reforming environment. This factor causes an increase in the SOFC power density of 6.62%. Although the economic analysis shows that the proposed fuel processor provides a higher capital cost, it offers a reducing active area of the SOFC stack and the most favorable process economics in term of net cost saving.

  15. Electrolytic reduction of mixed (Fe, Ti) oxide using molten calcium chloride electrolyte

    International Nuclear Information System (INIS)

    Highlights: ► Tan et al. have electrolyzed mixtures of TiO2 and Fe2O3 to produce alloys containing Fe–Ti intermetallic phases such as FeTi and Fe2Ti using the FFC process. However, the produced alloys have a porous structure with many carbon impurities, e.g., titanium carbide (TiC). Most of the carbon contamination could be caused by the presence of carbon particles in the porous alloy structure. They did not mention any obvious ways of excluding carbon and other impurities, and only suggested that the use of mixed oxides with refined structures or using a single phase, namely ilmenite (FeO·TiO2), were methods of decreasing impurities in the formed alloys. For future industrialization, there is an urgent need for obvious ways of producing purer Fe–Ti alloys with dense structures, rather than porous structures, as these absorb carbon impurities. ► Finally, we successfully reduced to a highly purified Fe–Ti intermetallic alloy of FeTi and β-Ti (FeTi4) phases. FeTi phases of size around 5–10 μm were dispersed in a matrix of the β-Ti (FeTi4) phase. The carbon content of the electrolyzed alloy was as low as less than 0.01 mass%. It was suggested that the dense structure of the alloy of FeTi and β-Ti (FeTi4) avoided the inclusion of carbon particle impurities, unlike the porous alloy structure. - Abstract: The production of high-purity metals or alloys using effective technologies is critical for future industrialization. With this aim in mind, a fundamental study of electrolysis in molten CaCl2 electrolytes was conducted to develop a new production process for ferrotitanium (Fe–Ti) intermetallic alloys. Mixed solid oxides of TiO2 and Fe2O3 were used in a molar ratio of 5.44:1.00. In this composition of Ti and Fe, FeTi and β-Ti containing iron can co-exist in equilibrium. A mixed solid (Fe, Ti) oxide was reduced electrochemically in a molten CaCl2 electrolyte at 950 °C. The metallic samples formed by electrolytic reduction of the mixed solid (Fe, Ti

  16. Self-assembled titanium calcium oxide nanopatterns as versatile reactive nanomasks for dry etching lithographic transfer with high selectivity.

    Science.gov (United States)

    Faustini, Marco; Drisko, Glenna L; Letailleur, Alban A; Montiel, Rafael Salas; Boissière, Cédric; Cattoni, Andrea; Haghiri-Gosnet, Anne Marie; Lerondel, Gilles; Grosso, David

    2013-02-01

    We report the simple preparation of ultra-thin self-assembled nanoperforated titanium calcium oxide films and their use as reactive nanomasks for selective dry etching of silicon. This novel reactive nanomask is composed of TiO(2) in which up to 50% of Ti was replaced by Ca (Ca(x)Ti(1-x)O(2-x)). The system was prepared by evaporation induced self-assembly of dip-coated solution of CaCl(2), TiCl(4) and poly(butadiene-block-ethylene oxide) followed by 5 min of thermal treatment at 500 °C in air. The mask exhibits enhanced selectivity by forming a CaF(2) protective layer in the presence of a chemically reactive fluorinated plasma. In particular it is demonstrated that ordered nano-arrays of dense Si pillars, or deep cylindrical wells, with high aspect ratio i.e. lateral dimensions as small as 20 nm and height up to 200 nm, can be formed. Both wells and pillars were formed by tuning the morphology and the homogeneity of the deposited mask. The mask preparation is extremely fast and simple, low-cost and easily scalable. Its combination with reactive ion etching constitutes one of the first examples of what can be achieved when sol-gel chemistry is coupled with top-down technologies. The resulting Si nanopatterns and nanostructures are of high interest for applications in many fields of nanotechnology including electronics and optics. This work extends and diversifies the toolbox of nanofabrication methods. PMID:23247472

  17. Cross-talk between calcium-calmodulin and nitric oxide in abscisic acid signaling in leaves of maize plants

    Institute of Scientific and Technical Information of China (English)

    Jianrong Sang; Aying Zhang; Fan Lin; Mingpu Tan; Mingyi Jiang

    2008-01-01

    Using pharmacological and biochemical approaches,the signaling pathways between hydrogen peroxide (H2O2),calcium (Ca2+)-calmodulin (CAM),and nitric oxide (NO) in abscisic acid (ABA)-induced antioxidant defense were investigated in leaves of maize (Zea mays L.) plants.Treatments with ABA,H2O2,and CaCI2 induced increases in the generation of NO in maize mesophyll cells and the activity of nitric oxide synthase (NOS) in the cytosolic and microsomal fractions of maize leaves.However,such increases were blocked by the pretreatments with Ca2+ inhibitors and CaM antagonists.Meanwhile,pretreatments with two NOS inhibitors also suppressed the Ca2+-induced increase in the production of NO.On the other hand,treatments with ABA and the NO donor sodium nitroprusside (SNP) also led to increases in the concentration of cytosolic Ca2+ in protoplasts of mesophyll cells and in the expression of calmodulin 1 (CaMI) gene and the contents of CaM in leaves of maize plants,and the increases induced by ABA were reduced by the pretreatments with a NO scavenger and a NOS inhibitor.Moreover,SNP-induced increases in the expression of the antioxidant genes superoxide dismutase 4 (SOD4),cytosolic ascorbate peroxidase (cAPX),and glutathione reductase 1 (GRI) and the activities of the chloroplastic and cytosolic antioxidant enzymes were arrested by the pretreatments with Ca2+ inhibitors and CaM antagonists.Our results suggest that Ca2+-CaM functions both upstream and downstream of NO production,which is mainly from NOS,in ABA- and H2O2-induced antioxidant defense in leaves of maize plants.

  18. Indole-3-acetic acid-induced oxidative burst and an increase in cytosolic calcium ion concentration in rice suspension culture.

    Science.gov (United States)

    Nguyen, Hieu T H; Umemura, Kenji; Kawano, Tomonori

    2016-08-01

    Indole-3-acetic acid (IAA) is the major natural auxin involved in the regulation of a variety of growth and developmental processes such as division, elongation, and polarity determination in growing plant cells. It has been shown that dividing and/or elongating plant cells accompanies the generation of reactive oxygen species (ROS) and a number of reports have suggested that hormonal actions can be mediated by ROS through ROS-mediated opening of ion channels. Here, we surveyed the link between the action of IAA, oxidative burst, and calcium channel activation in a transgenic cells of rice expressing aequorin in the cytosol. Application of IAA to the cells induced a rapid and transient generation of superoxide which was followed by a transient increase in cytosolic Ca(2+) concentration ([Ca(2+)]c). The IAA-induced [Ca(2+)]c elevation was inhibited by Ca(2+) channel blockers and a Ca(2+) chelator. Furthermore, ROS scavengers effectively blocked the action of IAA on [Ca(2+)]c elevation. PMID:27149194

  19. A Simulation Study on the Feasibility of Radio Enhancement Therapy with Calcium Tungstate and Hafnium Oxide Nanoparticles

    CERN Document Server

    Sherck, Nicholas J

    2016-01-01

    Herein is a simulation study on the radio enhancement potential of calcium tungstate (CaWO4) and hafnium oxide (HfO2) nanoparticles (NPs) relative to gold (Au) NPs. The work utilizes the extensively studied Au NP as the "gold standard" to which the novel materials can be compared. All three materials were investigated in-silico with the software Penetration and Energy Loss of Positrons and Electrons (PENELOPE) developed by Francesc Salvat and distributed in the United States by the Radiation Safety Information Computational Center (RSICC) at Oak Ridge National Laboratory. The aims are: (1) Do CaWO4 and HfO2 NPs function like Au?, and (2) if not, how else might they function to enhance radio therapy? Our investigations have found that HfO2 likely functions as Au, but not as effectively. CaWO4 likely does not function as Au, and we propose that CaWO4 may exhibit cancer killing traits through its intrinsic UV luminescence property.

  20. A regenerable sorbent injection/filtration process for H{sub 2}S removal from hot gas

    Energy Technology Data Exchange (ETDEWEB)

    Higgins, R.J.; Ji, W.; Connors, M.J.; Jones, J.F.; Goldsmith, R.L. [CeraMem Corp., Waltham, MA (United States)

    1996-12-31

    The operational characteristics of a hot gas desulfurization process involving regenerable sorbent injection and its subsequent collection with a ceramic filtration device were studied utilizing a bench-scale transport reactor. Hydrogen sulfide removal from simulated hot gas was evaluated as a function of both zinc oxide-based sorbent physical and chemical characteristics and various process parameters. In addition, the sorbent capture efficiency and regenerability of the ceramic filtration device were evaluated, and regeneration of sulfided sorbents via injection into an oxidizing gas was studied. For both sorbent sulfidation and spent sorbent regeneration, gas-solid reaction occurred both in the duct and within layers of partially reacted sorbent captured by the ceramic filter. Very high sulfur removal efficiencies were obtained only in highly reducing hot gas compositions at or above about 700 C, using stoichiometric ratio (defined as ZnO/H{sub 2}S ratio) values of about 1.5, and sorbent particles of about 20 {micro}m or less in diameter. Under such conditions, the experimental data indicated that reaction of H{sub 2}S with zinc vapor formed by reduction of zinc oxide contributed appreciably to sulfur removal. Negligible zinc loss from the hot zone of the reactor was detected, apparently due to rapid formation of zinc sulfide product layers on zinc oxide particles. The ceramic filtration devices captured 100% of all sorbent particles and were fully regenerable over periods of several tens of injection/backpulse cleaning cycles. Spent sorbent could be fully regenerated rapidly at 850 C without problems due to exotherm generation.

  1. Concentration of strontium-90 from natural fresh waters by titanium-silica gel sorbent

    International Nuclear Information System (INIS)

    Extraction of 90Sr microamounts from fresh water of the Beloyarsk reservoir using titanium-silica gel sorbent (61.7 % SiO2, 32.8 % TiO2) was considered. Linearity region of strontium distribution under static conditions was ascertained. Applicatibility of diffusion model to a restricted cylinder and to sphere, for particles of cylindrical and irregular shape respectively, was shown. Diffusion coefficients were calculated. The sorbent and method proved to be effective for problems of radioactive strontium extraction at the backgropund of stable strontium and calcium in concentrations typical of natural waters

  2. The high-temperature sulphation behavior of barium-based sorbents during coal combustion

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, J.; Li, N.; Zhou, J.; Cao, X.; Liu, J.; Zhao, X.; Cen, K.

    2000-07-01

    In order to promote the sulfur removal efficiency during coal combustion, the high-temperature sulfation behavior of barium-based sorbents was studied. The sulfation product BaSO{sub 4} which did not decompose until 1,580 C had much better thermal stability than CaSO{sub 4} which rapidly decomposed at about 1,300 C. The desulfurization effect of barium salt Ba{sup 2+} was much better than calcium salt Ca{sup 2+} during coal combustion at about 1,200{approximately}1,300 C. The sulfur removal efficiency of barium-based sorbents could achieve 35.5% in industrial grate furnace.

  3. Characterizing Pyroxene Reaction Space in Calcium-Aluminum Rich Inclusions: Oxidation During CAI Rim Formation

    Science.gov (United States)

    Dyl, K. A.; Young, E. D.

    2009-12-01

    We define the reaction space that controls changes in pyroxene composition in CAIs and Wark-Lovering (WL) rims in an oxidizing solar nebula. Ti-rich pyroxenes in CAIs record a sub-solar oxygen fugacity (Ti3+/Ti4+~1.5). WL rim pyroxenes in the CAI Leoville 144A have a distinctly lower oxidation state.This difference supports WL rim condensation in an environment of increasing O2(g) and Mg(g) (Simon et al. 2005). We used the following phase components to identify four linearly independent reactions (Thompson 1982): diopside, CaTs (Al2Mg-1Si-1), T3 (Ti3+AlMg-1Si-1), T4 (Ti4+Al2Mg-1Si-2), En (MgCa-1), perovskite, O(g), Mg(g), SiO(g), and Ca(g). Compositional variation in this system is dominated by two reactions. The first is oxidation of Ti3+ via reaction with O and Mg in the gas phase: 1.5 O(g) + Mg(g) → ¼ Di + [Ti4+Mg3/4Ti3+-1Ca-1/4Si-1/2] (1). Pyroxene is produced and En is introduced. The second reaction (2) is perovskite formation. It is observed in the WL rim of Leoville 144A, and experiments confirm that an elevated Ti component converts pyroxene to perovskite(Gupta et al. 1973). MgCa-1 is the third linearly independent reaction (3). They combine to give: ½ Di + x Ca(g)→ x Mg(g)+ Pv + [Mg1/2-xSiTi4+-1Ca-1/2+x](2,3). Unlike (1), pyroxene is consumed in this reaction. The parameter x defines the extent of Mg-Ca exchange. When x > 0.5, WL rim formation occurs in an environment where Mg is volatile and Ca condenses. The reaction space defined by reactions (1) and (2,3) describes the transition from CAI interior to WL rims. WL rim pyroxene Ti contents, [CaTs], and Ca < 1 pfu are all explained in this space. The fourth linearly independent reaction is SiO(g):1/8 Di + ¼ Mg(g)→ ¾ SiO(g) + [Mg3/8Ca1/8Ti4+Ti3+-1Si-1/2](4). Silica reduction forms Ti4+, releasing SiO(g). (4) does not describe the oxidation of Ti3+ in WL rim pyroxene, but (1) - (4) results in En formation directly from the gas phase. This may explain WL rim analyses that have Si contents in excess

  4. DEGRADATION OF SM2ZR2O7 THERMAL BARRIER COATING CAUSED BY CALCIUM-MAGNESIUM-ALUMINUM-SILICON OXIDE (CMAS) DEPOSITION

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Honglong; Sheng, Zhizhi; Tarwater, Emily; Zhang, Xingxing; Dasgupta, Sudip; Fergus, Jeffrey

    2015-03-16

    Rare earth zirconates are promising materials for use as thermal barrier coatings in gas turbine engines. Among the lanthanide zirconate materials, Sm2Zr2O7 with the pyrochlore structure has lower thermal conductivity and better corrosion resistance against calcium-magnesium-aluminum-silicon oxide (CMAS). In this work, after reaction with CMAS, the pyrochlore structure transforms to the cubic fluorite structure and Ca2Sm8(SiO4)6O2 forms in elongated grain.

  5. Alterations of rat liver mitochondrial oxidative phosphorylation and calcium uptake by benzo[a]pyrene

    International Nuclear Information System (INIS)

    We report that oxidative phosphorylation and Ca2+ uptake processes are enhanced in liver mitochondria isolated from benzo[a]pyrene (B[a]P)-treated rats. The carcinogen did not affect either the respiratory control index or the Ca2+ control ratio. B[a]P treatment increased the oxidation rate of several substrates that donate electrons at the level of all three coupling sites, either the ADP- or Ca2+-stimulated rates or those observed after ADP or Ca2+ exhaustion. However, the efficiency of energy coupling was maintained because both ADP/O and Ca2+/site ratios remained unchanged. The electron flow through NADH-oxidase, NADH-duroquinone reductase, NADH-juglone reductase, NADH-cytochrome c reductase, succinate-cytochrome c reductase, and cytochrome c oxidase was enhanced by B[a]P; however, succinate dehydrogenase activity was not affected. All these effects depended on the time post B[a]P administration, with a greater increase close to 48 h after administration of the carcinogen. The contents of cytochromes b, c1, and a + a3 from liver mitochondria, especially those isolated 48 h after B[a]P, were also significantly increased, although cytochrome c levels was just lightly increased 24 h after B[a]P treatment. These results suggest that B[a]P treatment stimulates mitochondrial respiration by increasing the level of several components of the mitochondrial respiratory chain. This may reflect mitochondrial adaptation to the cellular energy requirements of cell division in the neoplastic transformation process

  6. Octahedral molecular sieve sorbents and catalysts

    Science.gov (United States)

    Li, Liyu [Richland, WA; King, David L [Richland, WA

    2010-04-20

    Octahedral molecular sieve sorbents and catalysts are disclosed, including silver hollandite and cryptomelane. These materials can be used, for example, to catalyze the oxidation of CO.sub.x (e.g., CO), NO.sub.x (e.g., NO), hydrocarbons (e.g., C.sub.3H.sub.6) and/or sulfur-containing compounds. The disclosed materials also may be used to catalyze other reactions, such as the reduction of NO.sub.2. In some cases, the disclosed materials are capable of sorbing certain products from the reactions they catalyze. Silver hollandite, in particular, can be used to remove a substantial portion of certain sulfur-containing compounds from a gas or liquid by catalysis and/or sorption. The gas or liquid can be, for example, natural gas or a liquid hydrocarbon.

  7. Development of the advanced coolside sorbent injection process for SO2

    International Nuclear Information System (INIS)

    The goal of this work was to develop a low-capital-cost process capable of over 90% SO2 removal as an economically attractive option for compliance with the Clean Air Act. The Advanced Coolside Process uses a contactor to simultaneously remove fly ash and saturate the flue gas with water, followed by sorbent injection into the highly humid flue gas and collection of the sorbent by the existing particulate collector High sorbent utilization is achieved by sorbent recycle. The original performance targets of 90% SO2 removal and 60% sorbent utilization were exceeded in 1000 acfm pilot plant operations using commercial hydrated lime as the only sorbent. Process optimization simplified the process equipment, resulting in significant cost reduction. Recent accomplishments include completion of equipment testing and sorbent optimization, a waste management study, and a long-term performance test. An economic evaluation for the optimized process projects capital costs 55% to 60 % less than those of limestone forced oxidation wet FGD. The projected levelized control cost is 15% to 35% lower than wet FGD (25% lower for a 260 MWe plant burning a 2.5% sulfur coal), depending on plant size and coal sulfur content

  8. Development of the advanced coolside sorbent injection process for SO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Withum, J.A.; Maskew, J.T.; Rosenhoover, W.A. [Consol, Inc., Library, PA (United States)] [and others

    1995-11-01

    The goal of this work was to develop a low-capital-cost process capable of over 90% SO{sub 2} removal as an economically attractive option for compliance with the Clean Air Act. The Advanced Coolside Process uses a contactor to simultaneously remove fly ash and saturate the flue gas with water, followed by sorbent injection into the highly humid flue gas and collection of the sorbent by the existing particulate collector High sorbent utilization is achieved by sorbent recycle. The original performance targets of 90% SO{sub 2} removal and 60% sorbent utilization were exceeded in 1000 acfm pilot plant operations using commercial hydrated lime as the only sorbent. Process optimization simplified the process equipment, resulting in significant cost reduction. Recent accomplishments include completion of equipment testing and sorbent optimization, a waste management study, and a long-term performance test. An economic evaluation for the optimized process projects capital costs 55% to 60 % less than those of limestone forced oxidation wet FGD. The projected levelized control cost is 15% to 35% lower than wet FGD (25% lower for a 260 MWe plant burning a 2.5% sulfur coal), depending on plant size and coal sulfur content.

  9. Calcium-binding sites of calmodulin and electron transfer by inducible nitric oxide synthase.

    Science.gov (United States)

    Gribovskaja, Irena; Brownlow, Kaleb C; Dennis, Sam J; Rosko, Andrew J; Marletta, Michael A; Stevens-Truss, Regina

    2005-05-24

    Like that of the neuronal nitric oxide synthase (nNOS), the binding of Ca(2+)-bound calmodulin (CaM) also regulates the activity of the inducible isoform (iNOS). However, the role of each of the four Ca(2+)-binding sites of CaM in the activity of iNOS is unclear. Using a series of single-point mutants of Drosophila melanogaster CaM, the effect that mutating each of the Ca(2+)-binding sites plays in the transfer of electrons within iNOS has been examined. The same Glu (E) to Gln (Q) mutant series of CaM used previously [Stevens-Truss, R., Beckingham, K., and Marletta, M. A. (1997) Biochemistry 36, 12337-12345] to study the role of the Ca(2+)-binding sites in the activity of nNOS was used for these studies. We demonstrate here that activity of iNOS is dependent on Ca(2+) being bound to sites II (B2Q) and III (B3Q) of CaM. Nitric oxide ((*)NO) producing activity (as measured using the hemoglobin assay) of iNOS bound to the B2Q and B3Q CaMs was found to be 41 and 43% of the wild-type activity, respectively. The site I (B1Q) and site IV (B4Q) CaM mutants only minimally affected (*)NO production (95 and 90% of wild-type activity, respectively). These results suggest that NOS isoforms, although all possessing a prototypical CaM binding sequence and requiring CaM for activity, interact with CaM differently. Moreover, iNOS activation by CaM, like nNOS, is not dependent on Ca(2+) being bound to all four Ca(2+)-binding sites, but has specific and distinct requirements. This novel information, in addition to helping us understand NOS, should aid in our understanding of CaM target activation. PMID:15896003

  10. Physicochemical properties and in vitro cytocompatibility of modified titanium surfaces prepared via micro-arc oxidation with different calcium concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Sui-Dan; Zhang, Hui [Guanghua School of Stomatology, Hospital of Stomatology, Guangdong Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou 510055 (China); Dong, Xu-Dong [Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, BC V6T 1Z3 (Canada); Ning, Cheng-Yun [College of Material Science and Engineering, South China University of Technology, Guangzhou 510641 (China); Fok, Alex S.L. [Minnesota Dental Research Center of Biomaterials and Biomechanics, School of Dentistry, University of Minnesota, Minneapolis, MN 55414 (United States); Wang, Yan, E-mail: wyan65@163.com [Guanghua School of Stomatology, Hospital of Stomatology, Guangdong Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou 510055 (China)

    2015-02-28

    Highlights: • MAO coating improves the surface characteristics and cytocompatibility of titanium. • Composition of MAO coating varies with the electrolyte concentration. • MAO coating properties can be optimized by adjusting the electrolyte concentration. • Higher CA concentration contributes to more favorable MAO coating cytocompatibility. - Abstract: Objective: To explore the effect of calcium concentration in the electrolyte solution on the physicochemical properties and biocompatibility of coatings formed by micro-arc oxidation (MAO) on titanium surfaces. Methods: The surfaces of pure titanium plates were modified by MAO in an electrolytic solution containing calcium acetate (CA; C{sub 4}H{sub 6}CaO{sub 4}) at concentrations of 0.05, 0.1, 0.2, or 0.3 M and β-glycerophosphate disodium salt pentahydrate (β-GP; C{sub 3}H{sub 7}Na{sub 2}O{sub 6}P·5H{sub 2}O) at a fixed concentration of 0.02 M. Surface topography, elemental characteristics, phase composition, and roughness were investigated by scanning electron microscopy, energy-dispersive X-ray analysis, X-ray diffraction, and a surface roughness tester, respectively. To assess the cytocompatibility and osteoinductivity of the surfaces, MC3T3-E1 preosteoblasts were cultured on the surfaces in vitro, and cell morphology, adhesion, proliferation, and differentiation were observed. Results: The porous MAO coating was composed primarily of TiO{sub 2} rutile and anatase. The amount of TiO{sub 2} rutile, the Ca/P ratio, and the surface roughness of the MAO coating increased with increasing CA concentration in the electrolyte solution. Ca{sub 3}(PO{sub 4}){sub 2}, CaCO{sub 3}, and CaTiO{sub 3} were formed on MAO-treated surfaces prepared with CA concentrations of 0.2 and 0.3 M. Cell proliferation and differentiation increased with increasing CA concentration, with MC3T3-E1 cells exhibiting favorable morphologies for bone–implant integration. Conclusions: MAO coating improves the surface characteristics and

  11. Physicochemical properties and in vitro cytocompatibility of modified titanium surfaces prepared via micro-arc oxidation with different calcium concentrations

    International Nuclear Information System (INIS)

    Highlights: • MAO coating improves the surface characteristics and cytocompatibility of titanium. • Composition of MAO coating varies with the electrolyte concentration. • MAO coating properties can be optimized by adjusting the electrolyte concentration. • Higher CA concentration contributes to more favorable MAO coating cytocompatibility. - Abstract: Objective: To explore the effect of calcium concentration in the electrolyte solution on the physicochemical properties and biocompatibility of coatings formed by micro-arc oxidation (MAO) on titanium surfaces. Methods: The surfaces of pure titanium plates were modified by MAO in an electrolytic solution containing calcium acetate (CA; C4H6CaO4) at concentrations of 0.05, 0.1, 0.2, or 0.3 M and β-glycerophosphate disodium salt pentahydrate (β-GP; C3H7Na2O6P·5H2O) at a fixed concentration of 0.02 M. Surface topography, elemental characteristics, phase composition, and roughness were investigated by scanning electron microscopy, energy-dispersive X-ray analysis, X-ray diffraction, and a surface roughness tester, respectively. To assess the cytocompatibility and osteoinductivity of the surfaces, MC3T3-E1 preosteoblasts were cultured on the surfaces in vitro, and cell morphology, adhesion, proliferation, and differentiation were observed. Results: The porous MAO coating was composed primarily of TiO2 rutile and anatase. The amount of TiO2 rutile, the Ca/P ratio, and the surface roughness of the MAO coating increased with increasing CA concentration in the electrolyte solution. Ca3(PO4)2, CaCO3, and CaTiO3 were formed on MAO-treated surfaces prepared with CA concentrations of 0.2 and 0.3 M. Cell proliferation and differentiation increased with increasing CA concentration, with MC3T3-E1 cells exhibiting favorable morphologies for bone–implant integration. Conclusions: MAO coating improves the surface characteristics and cytocompatibility of titanium for osseointegration. Higher CA concentration in the MAO

  12. Role of calcium oxide in sludge granulation and methanogenesis for the treatment of palm oil mill effluent using UASB reactor

    International Nuclear Information System (INIS)

    Graphical abstract: SEM micrograph of granules; Outer surface of the granule; Scanning electron micrographs of the granule: Archaea (Methanosarcina sp.) showing the arrangement of bacterial cells in granule surrounded by extracellular polymeric substances (EPS), the seed sludge and granules sampled on day 150. Highlights: ► Examine the treatability of POME and effects of CaO–CKD on the granulation process in UASB reactors. ► The main objective was to determine the influent CaO–CKD concentration and the relationship between the CaO concentration in the feed and biomass accumulation, specific granulation, methanogenic activity, and the density and composition of granules. ► The biomass concentration profiles along the reactors and the size distribution of granules were also measured to track and to assess granulation, methanogenesis, and COD removal on levels at the industrial scale. ► SEM micrograph are showing smooth surface of granule with a large opening cavities likely for biogas escape. - Abstract: The granulation process in palm oil mill effluent using calcium oxide-cement kiln dust (CaO–CKD) provides an attractive and cost effective treatment option. In this study the efficiency of CaO–CKD at doses of 1.5–20 g/l was tested in batch experiments and found that 10 g of CaO/l caused the greatest degradation of VFA, butyrate and acetate. An upflow anaerobic sludge blanket (UASB) reactor was operated continuously at 35 °C for 150 days to investigate the effect of CaO–CKD on sludge granulation and methanogenesis during start-up. The treatment of POME emphasized the influence of varying organic loading rates (OLR). Up to 94.9% of COD was removed when the reactor was fed with the 15.5–65.5 g-COD g/l at an OLR of 4.5–12.5 kg-COD/m3 d, suggesting the feasibility of using CaO in an UASB process to treat POME. The ratio of volatile solids/total solids (VS/TS) and volatile fatty acids in the anaerobic sludge in the UASB reactor decreased

  13. Cinnamaldehyde and cinnamaldehyde-containing micelles induce relaxation of isolated porcine coronary arteries: role of nitric oxide and calcium

    Directory of Open Access Journals (Sweden)

    Raffai G

    2014-05-01

    Full Text Available Gábor Raffai,1 Byungkuk Kim,1 Sanga Park,1 Gilson Khang,1 Dongwon Lee,1 Paul M Vanhoutte1,21World Class University, Department of BIN Fusion Technology, Chonbuk National University, Jeonju, Jeonbuk, South Korea; 2Department of Pharmacology and Pharmacy and State Key Laboratory for Pharmaceutical Biotechnology, Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong, Special Administrative Region, ChinaBackground and purpose: Cinnamaldehyde, a major component of cinnamon, induces the generation of reactive oxygen species and exerts vasodilator and anticancer effects, but its short half-life limits its clinical use. The present experiments were designed to compare the acute relaxing properties of cinnamaldehyde with those of self-assembling polymer micelles either loaded with cinnamaldehyde or consisting of a polymeric prodrug [poly(cinnamaldehyde] that incorporates the compound in its backbone.Methods: Rings of porcine coronary arteries were contracted with the thromboxane A2 receptor agonist U46619 or 40 mM KCl, and changes in isometric tension were recorded.Results: Cinnamaldehyde induced concentration-dependent but endothelium-independent, nitric oxide synthase (NOS-independent, cyclooxygenase-independent, soluble guanylyl cyclase (sGC-independent, calcium-activated potassium-independent, and TRPA1 channel-independent relaxations. Cinnamaldehyde also inhibited the contractions induced by 40 mM KCl Ca2+ reintroduction in 40 mM KCl Ca2+-free solution or by the Ca2+ channel opener Bay K8644. Cinnamaldehyde-loaded control micelles induced complete, partly endothelium-dependent relaxations sensitive to catalase and inhibitors of NOS or sGC, but not cyclooxygenase or TRPA1, channels. Cinnamaldehyde-loaded micelles also inhibited contractions induced by 40 mM KCl Ca2+ reintroduction or Bay K8644. Poly(cinnamaldehyde micelles induced only partial, endothelium-dependent relaxations that were reduced by inhibitors of NOS or sGC and by

  14. Role of calcium oxide in sludge granulation and methanogenesis for the treatment of palm oil mill effluent using UASB reactor

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, Anwar, E-mail: anwarak218@yahoo.co.uk [Faculty of Civil Engineering and Earth Resources, University Malaysia Pahang (UMP), Lebuhraya Tun Razak, 26300 Gambang, Kuantan, Pahang (Malaysia); Ghufran, Rumana; Wahid, Zularisam Abd. [Faculty of Civil Engineering and Earth Resources, University Malaysia Pahang (UMP), Lebuhraya Tun Razak, 26300 Gambang, Kuantan, Pahang (Malaysia)

    2011-12-30

    Graphical abstract: SEM micrograph of granules; Outer surface of the granule; Scanning electron micrographs of the granule: Archaea (Methanosarcina sp.) showing the arrangement of bacterial cells in granule surrounded by extracellular polymeric substances (EPS), the seed sludge and granules sampled on day 150. Highlights: Black-Right-Pointing-Pointer Examine the treatability of POME and effects of CaO-CKD on the granulation process in UASB reactors. Black-Right-Pointing-Pointer The main objective was to determine the influent CaO-CKD concentration and the relationship between the CaO concentration in the feed and biomass accumulation, specific granulation, methanogenic activity, and the density and composition of granules. Black-Right-Pointing-Pointer The biomass concentration profiles along the reactors and the size distribution of granules were also measured to track and to assess granulation, methanogenesis, and COD removal on levels at the industrial scale. Black-Right-Pointing-Pointer SEM micrograph are showing smooth surface of granule with a large opening cavities likely for biogas escape. - Abstract: The granulation process in palm oil mill effluent using calcium oxide-cement kiln dust (CaO-CKD) provides an attractive and cost effective treatment option. In this study the efficiency of CaO-CKD at doses of 1.5-20 g/l was tested in batch experiments and found that 10 g of CaO/l caused the greatest degradation of VFA, butyrate and acetate. An upflow anaerobic sludge blanket (UASB) reactor was operated continuously at 35 Degree-Sign C for 150 days to investigate the effect of CaO-CKD on sludge granulation and methanogenesis during start-up. The treatment of POME emphasized the influence of varying organic loading rates (OLR). Up to 94.9% of COD was removed when the reactor was fed with the 15.5-65.5 g-COD g/l at an OLR of 4.5-12.5 kg-COD/m{sup 3} d, suggesting the feasibility of using CaO in an UASB process to treat POME. The ratio of volatile solids

  15. Effect of electrolysis voltage on electrochemical reduction of titanium oxide to titanium in molten calcium chloride

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The electrochemical reduction of solid TiO2 directly to solid metal is a ptomising alternative to the current Kroll process. The present work is aimed at studying the effect of electrolysis voltage on the rate of electrochemical reduction. The products of electrochemical reduction of TiO2 and Ti2O were examined using the scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques. The results show that Ti2O was reduced to low valent titanium oxide at 1.5 -1.7 V, which was the result of ionization of oxygen. TiO2 and Ti2O were reduced to titanium metal at 2.1-3.1 V, which was the co-action of ionization of oxygen and calciothermic reduction. The oxygen content decreased rapidly with voltage increasing from 2.1 to 2.6 V, while it changed little from 2.6 to 3.1 V. The optimized cell voltage was 2.6-3.1 V.

  16. Biocorrosion resistance of coated magnesium alloy by microarc oxidation in electrolyte containing zirconium and calcium salts

    Science.gov (United States)

    Wang, Ya-Ming; Guo, Jun-Wei; Wu, Yun-Feng; Liu, Yan; Cao, Jian-Yun; Zhou, Yu; Jia, De-Chang

    2014-09-01

    The key to use magnesium alloys as suitable biodegradable implants is how to adjust their degradation rates. We report a strategy to prepare biocompatible ceramic coating with improved biocorrosion resistance property on AZ91D alloy by microarc oxidation (MAO) in a silicate-K2ZrF6 solution with and without Ca(H2PO4)2 additives. The microstructure and biocorrosion of coatings were characterized by XRD and SEM, as well as electrochemical and immersion tests in simulated body fluid (SBF). The results show that the coatings are mainly composed of MgO, Mg2SiO4, m-ZrO2 phases, further Ca containing compounds involve the coating by Ca(H2PO4)2 addition in the silicate-K2ZrF6 solution. The corrosion resistance of coated AZ91D alloy is significantly improved compared with the bare one. After immersing in SBF for 28 d, the Si-Zr5-Ca0 coating indicates a best corrosion resistance performance.

  17. Nanosilica supported CaO: A regenerable and mechanically hard CO2 sorbent at Ca-looping conditions

    International Nuclear Information System (INIS)

    Highlights: • A synthetic CO2 sorbent is prepared by impregnation of calcium nitrate on a nanosilica matrix. • Sintering of the nascent CaO in the calcination stage of carbonation/calcination cycles is hindered. • CaO conversion reaches a stable value well above the residual conversion of natural limestone. • Particle fragmentation as caused by ultrasonic irradiation in a liquid dispersion is hindered. - Abstract: This work presents a CO2 sorbent that may be synthesized from low-cost and widely available materials following a simple method basically consisting of impregnation of a nanostructured silica support with a saturated solution of calcium nitrate. In a first impregnation stage, the use of a stoichiometric CaO/SiO2 ratio serves to produce a calcium silicate matrix after calcination. This calcium silicate matrix acts as a thermally stable and mechanically hard support for CaO deposited on it by further impregnation. The CaO-impregnated sorbent exhibits a stable CaO conversion at Ca-looping conditions whose value depends on the CaO wt% deposited on the calcium silicate matrix, which can be increased by successive reimpregnations. A 10 wt% CaO impregnated sorbent reaches a stable conversion above 0.6 whereas the stable conversion of a 30 wt% CaO impregnated sorbent is around 0.3, which is much larger than the residual conversion of CaO derived from natural limestone (between 0.07 and 0.08). Moreover, particle size distribution measurements of samples predispersed in a liquid and subjected to high energy ultrasonic waves indicate that the CaO-impregnated sorbent has a relatively high mechanical strength as compared to limestone derived CaO

  18. Calcium manganite as oxygen electrode materials for reversible solid oxide fuel cell.

    Science.gov (United States)

    Ni, Chengsheng; Irvine, John T S

    2015-01-01

    For an efficient high-temperature reversible solid oxide fuel cell (RSOFC), the oxygen electrode should be highly active for the conversion between oxygen anions and oxygen gas. CaMnO(3-δ) (CM) is a perovskite that can be readily reduced with the formation of Mn(3+) giving rise to oxygen defective phases. CM is examined here as the oxygen electrode for a RSOFC. CaMn(0.9)Nb(0.1)O(3-δ) (CMN) with Nb doping shows superior electric conductivity (125 S cm(-1) at 700 °C) compared with CM (1-5 S cm(-1) at 700 °C) in air which is also examined for comparison. X-ray diffraction (XRD) data show that CM and CMN are compatible with the widely used yttria-stabilized zirconia (YSZ) electrolyte up to 950 °C. Both materials show a thermal expansion coefficient (TEC) close to 10.8-10.9 ppm K(-1) in the temperature range between 100-750 °C, compatible with that of YSZ. Polarization curves and electrochemical impedance spectra for both fuel cell and steam electrolysis modes were investigated at 700 °C, showing that CM presented a polarization resistance of 0.059 Ω cm(2) under a cathodic bias of -0.4 V while CMN gave a polarization resistance of 0.081 Ω cm(2) under an anodic bias of 0.4 V. The phase stability up to 900 °C of these materials was investigated with thermogravimetric analysis (TGA) and variable temperature XRD. PMID:26212316

  19. Palmitate induces ER calcium depletion and apoptosis in mouse podocytes subsequent to mitochondrial oxidative stress.

    Science.gov (United States)

    Xu, S; Nam, S M; Kim, J-H; Das, R; Choi, S-K; Nguyen, T T; Quan, X; Choi, S J; Chung, C H; Lee, E Y; Lee, I-K; Wiederkehr, A; Wollheim, C B; Cha, S-K; Park, K-S

    2015-01-01

    Pathologic alterations in podocytes lead to failure of an essential component of the glomerular filtration barrier and proteinuria in chronic kidney diseases. Elevated levels of saturated free fatty acid (FFA) are harmful to various tissues, implemented in the progression of diabetes and its complications such as proteinuria in diabetic nephropathy. Here, we investigated the molecular mechanism of palmitate cytotoxicity in cultured mouse podocytes. Incubation with palmitate dose-dependently increased cytosolic and mitochondrial reactive oxygen species, depolarized the mitochondrial membrane potential, impaired ATP synthesis and elicited apoptotic cell death. Palmitate not only evoked mitochondrial fragmentation but also caused marked dilation of the endoplasmic reticulum (ER). Consistently, palmitate upregulated ER stress proteins, oligomerized stromal interaction molecule 1 (STIM1) in the subplasmalemmal ER membrane, abolished the cyclopiazonic acid-induced cytosolic Ca(2+) increase due to depletion of luminal ER Ca(2+). Palmitate-induced ER Ca(2+) depletion and cytotoxicity were blocked by a selective inhibitor of the fatty-acid transporter FAT/CD36. Loss of the ER Ca(2+) pool induced by palmitate was reverted by the phospholipase C (PLC) inhibitor edelfosine. Palmitate-dependent activation of PLC was further demonstrated by following cytosolic translocation of the pleckstrin homology domain of PLC in palmitate-treated podocytes. An inhibitor of diacylglycerol (DAG) kinase, which elevates cytosolic DAG, strongly promoted ER Ca(2+) depletion by low-dose palmitate. GF109203X, a PKC inhibitor, partially prevented palmitate-induced ER Ca(2+) loss. Remarkably, the mitochondrial antioxidant mitoTEMPO inhibited palmitate-induced PLC activation, ER Ca(2+) depletion and cytotoxicity. Palmitate elicited cytoskeletal changes in podocytes and increased albumin permeability, which was also blocked by mitoTEMPO. These data suggest that oxidative stress caused by saturated FFA

  20. Highly stable and regenerable Mn-based/SBA-15 sorbents for desulfurization of hot coal gas

    International Nuclear Information System (INIS)

    Highlights: ► A series of mesoporous CuxMnyOz/SBA-15 sorbents were fabricated for hot coal gas desulfurization. ► 1Cu9Mn/SBA-15 sorbent with high breakthrough sulfur capacity is high stable and regenerable. ► Utilization of SBA-15 constrained the sintering and pulverization of sorbents. - Abstract: A series of mesoporous xCuyMn/SBA-15 sorbents with different Cu/Mn atomic ratios were prepared by wet impregnation method and their desulfurization performance in hot coal gas was investigated in a fixed-bed quartz reactor in the range of 700–850 °C. The successive nine desulfurization–regeneration cycles at 800 °C revealed that 1Cu9Mn/SBA-15 presented high performance with durable regeneration ability due to the high dispersion of Mn2O3 particles incorporated with a certain amount of copper oxides. The breakthrough sulfur capacity of 1Cu9Mn/SBA-15 observed 800 °C is 13.8 g S/100 g sorbents, which is remarkably higher than these of 40 wt%LaFeO3/SBA-15 (4.8 g S/100 g sorbents) and 50 wt%LaFe2Ox/MCM-41 (5.58 g S/100 g sorbents) used only at 500–550 °C. This suggested that the loading of Mn2O3 active species with high thermal stability to SBA-15 support significantly increased sulfur capacity at relatively higher sulfidation temperature. The fresh and used xCuyMn/SBA-15 sorbents were characterized by means of BET, XRD, XPS, XAES, TG/DSC and HRTEM techniques, confirmed that the structure of the sorbents remained intact before and after hot coal gas desulfurization.

  1. Electro membrane extraction using sorbent filled porous membrane bag.

    Science.gov (United States)

    Naing, Nyi Nyi; Li, Sam Fong Yau; Lee, Hian Kee

    2015-12-01

    Electro membrane extraction-solid-liquid phase microextraction (EME-SLPME) was developed for the first time to determine phenolic contaminants in water. The extraction system consisted of a solid/liquid interface that permitted a three-phase microextraction approach involving an aqueous sample (donor phase): an organic solvent-sorbent within a membrane bag, and an organic solvent (extractant phase), operated in a direct immersion sampling system. The sorbent, reduced graphene oxide/polyvinyl alcohol, synthesized using graphene oxide and polyvinyl alcohol by dispersing the graphene oxide in polyvinyl alcohol and chemically reducing it in aqueous solution. The prepared sorbent was dispersed in 1-octanol and the solution was immobilized by sonication in the membrane bag wall pores which was in contact with the aqueous donor solution and organic extractant solvent (1-octanol) in the main bag itself. The analytes were transported by application of an electrical potential difference of 100V across the sorbent/solvent phase from the aqueous sample into the organic extractant phase in the membrane bag. After extraction and derivatization, gas chromatography-mass spectrometry was used to determine the derivatized analytes. This proposed EME-LSPME procedure provided high extraction efficiency with relative recoveries up to 99.6%. A linearity range of between 0.05 and 100μgL(-1) with corresponding coefficients of determination (r(2)) of between 0.987 and 0.996 were obtained. The limits of detection were in the range of between 0.003 and 0.053μgL(-1). This proposed method was successfully applied to the extraction of phenolic contaminants from water sample. PMID:26530143

  2. Sorption of UO22+ on calcium carbonate

    International Nuclear Information System (INIS)

    Sorption of uranyl ions on calcium carbonate from aqueous solutions featuring different concentration of calcium nitrate was studied experimentally. It is shown that uranium sorption decreases with calcium concentration growth in solution, irrespective of the ratio of solid phase and solution masses. Specific sorption of uranium per unit of the sorbent surface depends linearly on the ratio of UO22+ and Ca2+ ions activities in solution with proportionality factor (sorption equilibrium constant) 1.71 ± 0.16 mol/m2 at 20 deg C

  3. High capacity carbon dioxide sorbent

    Energy Technology Data Exchange (ETDEWEB)

    Dietz, Steven Dean; Alptekin, Gokhan; Jayaraman, Ambalavanan

    2015-09-01

    The present invention provides a sorbent for the removal of carbon dioxide from gas streams, comprising: a CO.sub.2 capacity of at least 9 weight percent when measured at 22.degree. C. and 1 atmosphere; an H.sub.2O capacity of at most 15 weight percent when measured at 25.degree. C. and 1 atmosphere; and an isosteric heat of adsorption of from 5 to 8.5 kilocalories per mole of CO.sub.2. The invention also provides a carbon sorbent in a powder, a granular or a pellet form for the removal of carbon dioxide from gas streams, comprising: a carbon content of at least 90 weight percent; a nitrogen content of at least 1 weight percent; an oxygen content of at most 3 weight percent; a BET surface area from 50 to 2600 m.sup.2/g; and a DFT micropore volume from 0.04 to 0.8 cc/g.

  4. Decontamination formulation with sorbent additive

    Science.gov (United States)

    Tucker; Mark D. , Comstock; Robert H.

    2007-10-16

    A decontamination formulation and method of making that neutralizes the adverse health effects of both chemical and biological compounds, especially chemical warfare (CW) and biological warfare (BW) agents, and toxic industrial chemicals. The formulation provides solubilizing compounds that serve to effectively render the chemical and biological compounds, particularly CW and BW compounds, susceptible to attack, and at least one reactive compound that serves to attack (and detoxify or kill) the compound. The formulation includes at least one solubilizing agent, a reactive compound, a bleaching activator, a sorbent additive, and water. The highly adsorbent, water-soluble sorbent additive (e.g., sorbitol or mannitol) is used to "dry out" one or more liquid ingredients, such as the liquid bleaching activator (e.g., propylene glycol diacetate or glycerol diacetate) and convert the activator into a dry, free-flowing powder that has an extended shelf life, and is more convenient to handle and mix in the field.

  5. Handling, transport and dispersion of sorbent powder for in-furnace injection. Third year final report

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Liang-Shih; Bavarian, F.; Lee, R.J.; Hsia, Chung-wei; Abou-Zeida, E.; Jiang, Peijun; Dastidar, A.G.; Mahuli, S. [Ohio State Univ., Columbus, OH (United States)

    1993-09-01

    The purpose of this study is to explain, using fundamental theories of interparticle forces, the difference in transport and dispersion between various sorbents. This project is closely tied with 1.1 through the focus of maximum utilization of sorbent materials used in the LIMB process. Interparticle forces lead to agglomeration or removal to transport tube walls of the sorbent fine particles, reducing sulfur removal capabilities. In the first and second years, the pneumatic transport of sorbent powders was investigated for four typical sorbent materials, calcium carbonate, dolomite, dolomitic hydrate and hydrated lime. Results indicate that hydrated lime has the best dispersion and flowability. Studies in the third year involved investigating improving the performance of hydrated lime with additives. The addition of calcium liposulfonate to the water of hydration appears to improve both the dispersibility and reactivity of the resulting product hydrate. Increased reactivity is closely tied to available surface area for reaction, as expected. However, in applications where powder flowability becomes important, such as in the use of hydrate in flue-gas desulfurization, a balance between the flowability and surface area must be considered. If the powder has poor flowability, the added surface area may not be utilized. Powder dispersion and the high-temperature are used to determine the dispersibility of the modified and unmodified sorbents at room temperature and at typical furnace temperatures. Results verify that an increase in dispersibility is realized with the liposulfonate-modified hydrate. Phase 1 results show this increased dispersibility to be due to electrostatic repulsion between liposulfonate molecules on the surface of the dry powder.

  6. Calcium - urine

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/003603.htm Calcium - urine To use the sharing features on this ... enable JavaScript. This test measures the amount of calcium in urine. All cells need calcium in order ...

  7. Calcium supplements

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/007477.htm Calcium supplements To use the sharing features on this page, please enable JavaScript. WHO SHOULD TAKE CALCIUM SUPPLEMENTS? Calcium is an important mineral for the ...

  8. Demonstration of Mercury Sorbents to Meet DOE Customer Needs

    Energy Technology Data Exchange (ETDEWEB)

    Klasson, K.T.

    2000-05-08

    Many sorbents have been developed for the removal of mercury and heavy metals from water; however, the majority of data published to date do not address the removal of mercury to the target levels represented in this project. The application for which these sorbents were targeted for use was the removal of mercury from microgram-per-liter levels to low nanogram-per-liter levels. Overall, the thiol-based resins had the best performance when removing low concentrations of mercury in water at two U.S. Department of Energy facilities in field experiments. It was difficult to achieve the targeted low nanogram-per-liter levels at both sites; however, a substantial amount of mercury was removed by the resins. This is attributed to the mercury speciation, since filtration tests have shown that a significant portion of the mercury at each test location is particle bound or associated with particulate and colloidal matter. The engineered Self-Assembled Mercaptan on Mesoporous Silica (SAMMS) material proved to be as effective as some of the commercial sorbents in removing mercury at the Nonradiological Wastewater Treatment Plant (NRWTP) at Oak Ridge National Laboratory. The material performed almost as well as some of the best sorbents at the Upper East Fork Poplar Creek site at the Oak Ridge Y-12 Plant. The most effective sorbents were SAMMS; Keyle:X, by SolmeteX, Inc.; and SIR-200, by ResinTech, Inc. It was also found that the Keyle:X performed better at the NRWTP when the water was pretreated with hypochlorite to oxidize some mercury species. Because of the scattering of data, mathematical modeling was limited to predicting the behavior of active mercury. Since the field samples contained a substantial amount of particle-bound mercury, the mathematical models did not represent the field data very well. Nevertheless, it was useful to predict the performance of these sorbents at very low concentrations of mercury. Mathematical modeling was also used to investigate the

  9. Calcium Oscillations

    OpenAIRE

    Dupont, Geneviève; Combettes, Laurent; Bird, Gary S.; Putney, James W.

    2011-01-01

    Calcium signaling results from a complex interplay between activation and inactivation of intracellular and extracellular calcium permeable channels. This complexity is obvious from the pattern of calcium signals observed with modest, physiological concentrations of calcium-mobilizing agonists, which typically present as sequential regenerative discharges of stored calcium, a process referred to as calcium oscillations. In this review, we discuss recent advances in understanding the underlyin...

  10. Rhythmical changes of a level nitric oxide (NO in roots etiolated seedlings of pea (Pisum sativum L. and influence of exogenous calcium

    Directory of Open Access Journals (Sweden)

    A.K. Glyan’ko

    2014-12-01

    Full Text Available Studied time dynamics (during 60 mines a level oxide nitric (NO in cross cuts of roots 2 – day etiolated seedlings of pea sowing (Pisum sativum L. by use of fluorescent probe DAF-2DA and a fluorescent microscope depending on action exogenous calcium (Ca2+. During an exposition of seedlings on water, solution CaCl2 are shown fluctuation in level NO in roots – his increase and decrease that testifies to the certain rhythm in generation NO. Exogenous factors (Ca2+ change time dynamics of level NO in comparison with variant “water”. Ca2+chelate EGTA removes action exogenous calcium on rhythmical change of a level NO in roots. Results are discussed in aspect of close interference of signaling systems and molecules (Ca2+, NO, Н2О2.

  11. Large Particle Titanate Sorbents

    Energy Technology Data Exchange (ETDEWEB)

    Taylor-Pashow, K. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-10-08

    This research project was aimed at developing a synthesis technique for producing large particle size monosodium titanate (MST) to benefit high level waste (HLW) processing at the Savannah River Site (SRS). Two applications were targeted, first increasing the size of the powdered MST used in batch contact processing to improve the filtration performance of the material, and second preparing a form of MST suitable for deployment in a column configuration. Increasing the particle size should lead to improvements in filtration flux, and decreased frequency of filter cleaning leading to improved throughput. Deployment of MST in a column configuration would allow for movement from a batch process to a more continuous process. Modifications to the typical MST synthesis led to an increase in the average particle size. Filtration testing on dead-end filters showed improved filtration rates with the larger particle material; however, no improvement in filtration rate was realized on a crossflow filter. In order to produce materials suitable for column deployment several approaches were examined. First, attempts were made to coat zirconium oxide microspheres (196 µm) with a layer of MST. This proved largely unsuccessful. An alternate approach was then taken synthesizing a porous monolith of MST which could be used as a column. Several parameters were tested, and conditions were found that were able to produce a continuous structure versus an agglomeration of particles. This monolith material showed Sr uptake comparable to that of previously evaluated samples of engineered MST in batch contact testing.

  12. Desulfurization sorbent development activities at METC

    Energy Technology Data Exchange (ETDEWEB)

    Siriwardane, R.V.

    1995-06-01

    Development of a suitable regenerable sorbent is a major barrier issue in the hot gas cleanup program for integrated gasification combined-cycle (IGCC) systems. This has been a challenging problem during the last 20 years, since many of the sorbents developed in the program could not retain their reactivity and physical integrity during repeated cycles of sulfidation and regeneration reactions. A series of promising sorbents (METC 2-10), which were capable of sustaining their reactivity and physical integrity during repeated sulfidation/ regeneration cycles, have been developed at the Morgantown Energy Technology Center (METC). These sorbents were tested both in low-pressure (260 KPa/23 psig) and high-pressure (520 KPa/60.7 psig) fixed-bed reactors at 538{degrees}C (1000{degrees}F) with simulated coal gas. High-pressure testing was continued for 20 cycles with steam regeneration. A major research goal during the last year was to lower the cost of materials utilized during the sorbent preparation. The METC 9 sorbent was prepared by substituting low-cost materials for some of the materials in METC 6 sorbent. The sulfur capacity of the two sorbents were similar during the 20-cycle testing. METC 2 sorbent was exposed to coal gas in the Modular Gas Cleanup Rig and it was later tested in the high-pressure fixed-bed reactor. The reactivity of the METC 2 sorbent was unaffected by the exposure to the coal gas. Development of these sorbents will be continued for both fluid-bed and moving-bed applications.

  13. Antinociceptive Effect of Vardenafil on Carrageenan-Induced Hyperalgesia in Rat: involvement of Nitric Oxide/Cyclic Guanosine Monophosphate/Calcium Channels Pathway.

    Science.gov (United States)

    Gediz, Ezgi İkiz; Nacitarhan, Cahit; Minareci, Edibe; Sadan, Gulay

    2015-01-01

    In this study, we aimed to investigate the peripheral antinociception effects of specific phosphodiesterase 5 (PDE-5) inhibitor vardenafil on carrageenan-induced nociception in rats, and the role of calcium besides the L-arginine- nitric oxide (NO)- cyclic guanosine monophophate (cGMP) pathway in these effects. Hyperalgesia was induced by the intraplantar injection of 0.1 mL fresh carrageenan solution to right hind-paw whereas, saline as a vehicle of carrageenan was injected to the left paw. This procedure was used for measuring mechanic nociception pressure via an analgesimeter. Pressure which produced nociception was measured before (0 minute) and after(15, 30, 60 and 120 minutes) carrageenan injection. Local administration of vardenafil produced a dose-dependent antinociceptive effect. Pretreatment with N(W)-nitro-L-arginine methyl ester (L-NAME, nitric oxide synthase inhibitor), oxadiazolo (4, 3, a) quinoxalin -1-one (ODQ, inhibitor of guanylyl cyclase) or A23187 (calcium ionophore) decreased the effect of vardenafil. In contrast, L-arginine (nitric oxide donor) seemed to potentiate the vardenafil-induced antinociception. Our results suggest that phosphodiesterase type-5 inhibitor vardenafil may offer a new therapeutic tool to treat pain. It's effect was probably result from L-arginine/NO-cGMP pathway activation and Ca + 2 channels are also involved. PMID:26664380

  14. Macrophage activation by a vanadyl-aspirin complex is dependent on L-type calcium channel and the generation of nitric oxide

    International Nuclear Information System (INIS)

    Bone homeostasis is the result of a tight balance between bone resorption and bone formation where macrophage activation is believed to contribute to bone resorption. We have previously shown that a vanadyl(IV)-aspirin complex (VOAspi) regulates cell proliferation and differentiation of osteoblasts in culture. In this study, we assessed VOAspi and VO effects and their possible mechanism of action on a mouse macrophage cell line RAW 264.7. Both vanadium compounds inhibited cell proliferation in a dose-dependent manner. Nifedipine completely reversed the VOAspi-induced macrophage cytotoxicity, while it could not block the effect of VO. VOAspi also stimulated nitric oxide (NO) production, the oxidation of dihydrorhodamine 123 (DHR-123) and enhanced the expression of both constitutive and inducible isoforms of nitric oxide syntases (NOS). All these effects were abolished by nifedipine. Althogether our finding give evidence that VOAspi-induced macrophage cytotoxicity is dependent on L-type calcium channel and the generation of NO though the induction of eNOS and iNOS. Contrary, the parent compound VO exerted a cytotoxic effect by mechanisms independent of a calcium entry and the NO/NOS activation

  15. PENJERAPAN GAS CO HASIL PEMBAKARAN SAMPAH MENGGUNAKAN SORBENT TERMODIFIKASI DALAM REAKTOR FIXED BED

    Directory of Open Access Journals (Sweden)

    Mariana Mariana

    2013-11-01

    Full Text Available ADSORPTION OF CO FROM WASTE COMBUSTION USING MODIFIED SORBENT IN A FIXED BED REACTOR. Gases produced by garbage burning consist of dangerous gases such as CO, SO2 and other gases. Technology for reducing dangerous gases from incinerator outlet can be done by using a dry or wet process. The dry process is more economical process because of simple process, easy maintenance and no liquid waste as product. However, the weakness of the dry process is low absorption conversion and low gas removal efficiency. One way to overcome these problems is to use sorbent which has high reactivity. An inexpensive sorbent that commonly used is Ca(OH2. The aim of this research was to increase the reactivity of Ca(OH2 sorbent by using diatomaceous earth and compost as a source of silica and biosorbent, respectively. Diatomaceous earth contains CaO, SiO2 and Al2O3 and compost contains bacteria as a biosorbent that can convert CO to CO2 and CH4. The reaction between SiO2 and Ca(OH2 would form calcium silicate hydrate (CaO.SiO2.2H2O that has a high porosity and reactivity. The results showed that the reactivity of Ca(OH2 sorbent increased by addition of diatomaceous earth and compost. The results also showed that the sorption of CO gas increases with increasing of height of sorbent bed and temperature. The highest CO gas sorption was obtained at temperature of 150oC and sorbent bed height of 6 cm using the modified sorbent with Ca(OH2/DE/compost ratio of 3:1:1. Gas hasil pembakaran sampah terdiri dari gas-gas yang berbahaya seperti CO, SO2 dan lain sebagainya. Teknologi penghilangan gas-gas tersebut dapat dilakukan dengan menggunakan proses kering maupun proses basah. Penghilangan dengan proses kering lebih ekonomis karena sederhana, mudah pemeliharaan dan tidak menghasilkan limbah cair. Namun demikian, kelemahan proses kering adalah konversi absorpsi rendah dan efisiensi penyisihan  gas relatif kecil. Salah satu cara mengatasi masalah tersebut di atas adalah dengan

  16. Evaluation of Ohio fly ash/hydrated lime slurries and Type 1 cement sorbent slurries in the U.C. Pilot spray dryer facility. Final report, September 1, 1993--August 31, 1994

    Energy Technology Data Exchange (ETDEWEB)

    Keener, T.C.; Khang, S.J.; Meyers, G.R. [Cincinnati Univ., OH (United States)

    1995-02-01

    The objectives of this year`s work included an evaluation of the performance of fly ash/hydrated lime as well as hydrated cement sorbents for spray drying adsorption (SDA) of SO{sub 2} from a simulated high-sulfur flue gas. These sorbents were evaluated for several different hydration methods, and under different SDA operating conditions. In addition, the physical properties of surface area and porosity of the sorbents was determined. The most reactive fly ash/hydrated lime sorbent studied was prepared at room temperature with milled fly ash. Milling fly ash prior to hydration with lime did have a beneficial effect on calcium utilization. No benefit in utilization was experienced either by hydrating the slurries at a temperature of 90{degrees}C as compared to hydration at room temperature, or by increasing hydration time. While the surface areas varied greatly from sorbent to sorbent, the pore size distributions indicated ``ink bottle`` pores with surface porosity on the order of 0.5 microns. No correlation could be drawn between the surface area of the sorbents and calcium utilization. These results suggest that the composition of the resulting sorbent might be more important than its surface area. The most effective sorbent studied this year was produced by hydrating cement for 3 days at room temperature. This sorbent provided a removal efficiency and a calcium utilization over 25 percent higher than baseline results at an approach to saturation temperature of 30{degrees}F and a stoichiometric ratio of 0.9. A maximum SO{sub 2} removal efficiency of about 90 percent was experienced with this sorbent at an approach to saturation temperature of 20{degrees}F.

  17. Calcium Oxide Decomposed From Chicken’s and Goat’s Bones as Catalyst For Converting Discarded Cooking Oil to be Biodiesel

    Directory of Open Access Journals (Sweden)

    Aldes Lesbani

    2015-01-01

    Full Text Available Thermal decomposition of calcium oxide from chicken’s (Gallus gallus domesticus and goat’s (Capra Hircus Aegragus bones was prepared at temperature variations of 400, 500, 800, 900, 1000, and 1100 oC respectively. X-ray diffractometer (XRD, FT-IR and SEM were used for calcium oxide characterization. XRD diffraction pattern of the bone’s after thermal decomposition at 1100oC has similarity to the XRD standard diffraction pattern from Joint Committee on Powder Diffraction Standard (JCPDS. Diffractions of 2q values being used are 34.2o, 37.3o, 58.3o, 64.1o, and 67.3 o.  Ca-O presence in the samples was detected by FT-IR characterization at wavenumber of 354,90 cm-1. SEM profile show reducing size of bones after decomposition in both chicken’s and goat’s bones. Furthermore, the prepared calcium oxide was applied for biodiesel synthesis from discarded cooking oil through transesterification reaction. By applying the catalysts decomposed from chicken’s and goat’s bones, the biodiesel product showed characteristics as follows: biodiesel applied the chicken’s bone catalyst has fatty acid number of 0.56 mg/KOH, iod number of 22.41 g I2/100 g KOH, density of 0.88 g/cm3 and viscosity of 5.91 mm2/s, while biodiesel applied the goat’s bone catalyst has 0.56 mg/KOH, iod number of 21.57 g I2/100 g KOH, density of 0.88 g/cm3 and viscosity of 6.34 mm2/s. Those biodiesel’s characteristic values meet the National Standard of Indonesia (SNI for biodiesel.

  18. Reusability and Stability Tests of Calcium Oxide Based Catalyst (K2O/CaO-ZnO for Transesterification of Soybean Oil to Biodiesel

    Directory of Open Access Journals (Sweden)

    Istadi Istadi

    2016-03-01

    Full Text Available This paper was purposed for testing reusability and stability of calcium oxide-based catalyst (K2O/CaO-ZnO over transesterification reaction of soybean oil with methanol to produce biodiesel. The K2O/CaO-ZnO catalyst was synthesized by co-precipitation method of calcium and zinc nitrates followed by impregnation of potassium nitrate. The fresh and used catalysts were tested after regeneration. The catalysts were characterized by Scanning Electron Microscopy (SEM, X-ray Diffraction (XRD, and BET Surface Area in order to compare the catalyst structure between the fresh and used catalysts. The catalyst testing in transesterification proses was carried out at following operating conditions, i.e. catalyst weight of 6 wt.%, oil to methanol mole ratio of 1:15, and temperature of 60 oC. In addition, metal oxide leaching of K2O/CaO-ZnO catalyst during reaction was also tested. From the results, the catalysts exhibited high catalytic activity (80% fatty acid methyl ester (FAME yield after three-cycles of usage and acceptable reusability after regeneration. The catalyst also showed acceptable stability of catalytic activity, even after three-cycles of usage. Copyright © 2016 BCREC GROUP. All rights reserved Received: 10th November 2015; Revised: 16th January 2016; Accepted: 16th January 2016 How to Cite: Istadi, I., Mabruro, U., Kalimantini, B.A.,  Buchori, L., Anggoro, D.D. (2016. Reusability and Stability Tests of Calcium Oxide Based Catalyst (K2O/CaO-ZnO for Transesterification of Soybean Oil to Biodiesel. Bulletin of Chemical Reaction Engineering & Catalysis, 11 (1: 34-39. (doi:10.9767/bcrec.11.1.413.34-39 Permalink/DOI: http://dx.doi.org/10.9767/bcrec.11.1.413.34-39

  19. Dietary Calcium and Dairy Modulation of Oxidative Stress and Mortality in aP2-Agouti and Wild-type Mice

    OpenAIRE

    Antje Bruckbauer; Zemel, Michael B

    2009-01-01

    Oxidative and inflammatory stress have been implicated as major contributors to the aging process. Dietary Ca reduced both factors in short-term interventions, while milk exerted a greater effect than supplemental Ca. In this work, we examined the effects of life-long supplemental and dairy calcium on lifespan and life-span related biomarkers in aP2-agouti transgenic (model of diet-induced obesity) and wild-type mice fed obesigenic diets until their death. These data demonstrate that dairy Ca...

  20. Sorbent Structural Impacts Due to Humidity on Carbon Dioxide Removal Sorbents for Advanced Exploration Systems

    Science.gov (United States)

    Watson, David; Knox, James C.; West, Phillip; Stanley, Christine M.; Bush, Richard

    2015-01-01

    The Life Support Systems Project (LSSP) under the Advanced Exploration Systems (AES) program builds upon the work performed under the AES Atmosphere Resource Recovery and Environmental Monitoring (ARREM) project focusing on the numerous technology development areas. The CO2 removal and associated air drying development efforts are focused on improving the current state-of-the-art system on the International Space Station (ISS) utilizing fixed beds of sorbent pellets by seeking more robust pelletized sorbents, evaluating structured sorbents, and examining alternate bed configurations to improve system efficiency and reliability. A component of the CO2 removal effort encompasses structural stability testing of existing and emerging sorbents. Testing will be performed on dry sorbents and sorbents that have been conditioned to three humidity levels. This paper describes the sorbent structural stability screening efforts in support of the LSS Project within the AES Program.

  1. Fabrication and characterization of nano-HA-45S5 bioglass composite coatings on calcium-phosphate containing micro-arc oxidized CP-Ti substrates

    Energy Technology Data Exchange (ETDEWEB)

    Farnoush, Hamidreza, E-mail: farnoush@aut.ac.ir [Department of Metallurgy and Materials Engineering, Faculty of Engineering, University of Kashan, P.O. Box 87317-51167, Kashan (Iran, Islamic Republic of); Muhaffel, Faiz; Cimenoglu, Huseyin [Department of Metallurgical and Materials Engineering, Istanbul Technical University, 34469 Maslak, Istanbul (Turkey)

    2015-01-01

    Highlights: • Introducing a calcium-containing titanium oxide interlayer by MAO on CP-Ti. • EPD was utilized for HA and HA-BG coatings on MAO CP-Ti substrates. • Highest bonding strength was obtained for HA-BG/MAO 360 Ti sample. • Enhancement of corrosion resistance for HA-BG/MAO 360 Ti sample in SBF. - Abstract: In the present study, micro-arc oxidation (MAO) was carried out on commercially pure titanium (CP-Ti) to fabricate porous titanium oxide coatings containing calcium phosphates (CaP) at different applied voltages of 300, 330 and 360 V for 5 min. Subsequently, nano-hydroxyapatite (HA) and HA-45S5 bioglass (BG) composite were effectively coated on micro-arc oxidized substrate by electrophoretic deposition (EPD) at a constant voltage of 30 V for 120 s. The phase, structural agents, microstructure and composition of MAO interlayer and subsequent EPD coatings were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy and energy-dispersive X-ray spectroscopy, respectively. Thermal stability of the as-deposited coatings was analyzed by simultaneous differential scanning calorimetry and thermal gravimetery. The pull-off adhesion tests showed the highest bonding strength was obtained for HA-BG coating on micro-oxidized sample at 360 V. The results of potentiodynamic polarization and impedance spectroscopic measurements in simulated body fluid solution depicted that the combination of MAO treatment at 360 V and EPD of HA-BG composite could effectively increase the corrosion resistance of CP-Ti substrates.

  2. Fabrication and characterization of nano-HA-45S5 bioglass composite coatings on calcium-phosphate containing micro-arc oxidized CP-Ti substrates

    International Nuclear Information System (INIS)

    Highlights: • Introducing a calcium-containing titanium oxide interlayer by MAO on CP-Ti. • EPD was utilized for HA and HA-BG coatings on MAO CP-Ti substrates. • Highest bonding strength was obtained for HA-BG/MAO 360 Ti sample. • Enhancement of corrosion resistance for HA-BG/MAO 360 Ti sample in SBF. - Abstract: In the present study, micro-arc oxidation (MAO) was carried out on commercially pure titanium (CP-Ti) to fabricate porous titanium oxide coatings containing calcium phosphates (CaP) at different applied voltages of 300, 330 and 360 V for 5 min. Subsequently, nano-hydroxyapatite (HA) and HA-45S5 bioglass (BG) composite were effectively coated on micro-arc oxidized substrate by electrophoretic deposition (EPD) at a constant voltage of 30 V for 120 s. The phase, structural agents, microstructure and composition of MAO interlayer and subsequent EPD coatings were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy and energy-dispersive X-ray spectroscopy, respectively. Thermal stability of the as-deposited coatings was analyzed by simultaneous differential scanning calorimetry and thermal gravimetery. The pull-off adhesion tests showed the highest bonding strength was obtained for HA-BG coating on micro-oxidized sample at 360 V. The results of potentiodynamic polarization and impedance spectroscopic measurements in simulated body fluid solution depicted that the combination of MAO treatment at 360 V and EPD of HA-BG composite could effectively increase the corrosion resistance of CP-Ti substrates

  3. Effects of phosphates on microstructure and bioactivity of micro-arc oxidized calcium phosphate coatings on Mg-Zn-Zr magnesium alloy.

    Science.gov (United States)

    Pan, Y K; Chen, C Z; Wang, D G; Zhao, T G

    2013-09-01

    Calcium phosphate (CaP) coatings were prepared on Mg-Zn-Zr magnesium alloy by micro-arc oxidation (MAO) in electrolyte containing calcium acetate monohydrate (CH3COO)2Ca·H2O) and different phosphates (i.e. disodium hydrogen phosphate dodecahydrate (Na2HPO4·12H2O), sodium phosphate (Na3PO4·H2O) and sodium hexametaphosphate((NaPO3)6)). Scanning electron microscope (SEM), energy-dispersive X-ray spectrometry (EDS) and X-ray diffractometer (XRD) were employed to characterize the microstructure, elemental distribution and phase composition of the CaP coatings. Simulated body fluid (SBF) immersion test was used to evaluate the coating bioactivity and degradability. Systemic toxicity test was used to evaluate the coating biocompatibility. Fluoride ion selective electrode (ISE) was used to measure F(-) ions concentration during 30 days SBF immersion. The CaP coatings effectively reduced the corrosion rate and the surfaces of CaP coatings were covered by a new layer formed of numerous needle-like and scale-like apatites. The formation of these calcium phosphate apatites indicates that the coatings have excellent bioactivity. The coatings formed in (NaPO3)6-containging electrolyte exhibit thicker thickness, higher adhesive strength, slower degradation rate, better apatite-inducing ability and biocompatibility. PMID:23603036

  4. Extraction of polycyclic aromatic hydrocarbons with a magnetic sorbent composed of alginate, magnetite nanoparticles and multiwalled carbon nanotubes

    International Nuclear Information System (INIS)

    The article describes a magnetic composite sorbent for the extraction of traces of polycyclic aromatic hydrocarbons (PAHs) from water samples. The composite was prepared by caging Fe3O4 nanoparticles (NPs) and MWCNTs into calcium alginate beads. The large surface area of the MWCNTs and their π-interactions with the aromatic rings of PAHs obviously facilitate strong adsorption. The hydrophilicity of the calcium alginate cage, in turn, enhances the dispersibility of the sorbent in the water sample. Finally, the use of magnetic NPs facilitates a simple and fast separation of the sorbent. The composite sorbent was successfully applied to the extraction of PAHs from (spiked) water samples. PAHs were quantified by HPLC with fluorescence detection. Under optimized experimental conditions, the calibration plot is linear in the range of 5 to 50 μg∙L−1 for benzo[a]anthracene and benzo[a]pyrene, and 10 to 50 μg∙L−1 for benzo[b]fluoranthene. Other figures of merit include a limit of detection of 5 ng∙L−1 for benzo[a]anthracene and benzo(a)pyrene, and of 10 ng∙L−1 for benzo[b]fluoranthene, recoveries ranging from 92.0 to 97.7 %, and relative standard deviations of <5 %. The method has several attractive features including an easily prepared and eco-friendly sorbent, a convenient and fast extraction procedure, and a high extraction efficiency. (author)

  5. Oxidative stability of a heme iron-fortified bakery product: Effectiveness of ascorbyl palmitate and co-spray-drying of heme iron with calcium caseinate.

    Science.gov (United States)

    Alemán, Mercedes; Bou, Ricard; Tres, Alba; Polo, Javier; Codony, Rafael; Guardiola, Francesc

    2016-04-01

    Fortification of food products with iron is a common strategy to prevent or overcome iron deficiency. However, any form of iron is a pro-oxidant and its addition will cause off-flavours and reduce a product's shelf life. A highly bioavailable heme iron ingredient was selected to fortify a chocolate cream used to fill sandwich-type cookies. Two different strategies were assessed for avoiding the heme iron catalytic effect on lipid oxidation: ascorbyl palmitate addition and co-spray-drying of heme iron with calcium caseinate. Oxidation development and sensory acceptability were monitored in the cookies over one-year of storage at room temperature in the dark. The addition of ascorbyl palmitate provided protection against oxidation and loss of tocopherols and tocotrienols during the preparation of cookies. In general, ascorbyl palmitate, either alone or in combination with the co-spray-dried heme iron, prevented primary oxidation and hexanal formation during storage. The combination of both strategies resulted in cookies that were acceptable from a sensory point of view after 1year of storage. PMID:26593529

  6. Dietary Calcium and Dairy Modulation of Oxidative Stress and Mortality in aP2-Agouti and Wild-type Mice

    Directory of Open Access Journals (Sweden)

    Antje Bruckbauer

    2009-08-01

    Full Text Available Oxidative and inflammatory stress have been implicated as major contributors to the aging process. Dietary Ca reduced both factors in short-term interventions, while milk exerted a greater effect than supplemental Ca. In this work, we examined the effects of life-long supplemental and dairy calcium on lifespan and life-span related biomarkers in aP2-agouti transgenic (model of diet-induced obesity and wild-type mice fed obesigenic diets until their death. These data demonstrate that dairy Ca exerts sustained effects resulting in attenuated adiposity, protection against age-related muscle loss and reduction of oxidative and inflammatory stress in both mouse strains. Although these effects did not alter maximum lifespan, they did suppress early mortality in wild-type mice, but not in aP2-agouti transgenic mice.

  7. Development of a Steel-Slag-Based, Iron-Functionalized Sorbent for an Autothermal Carbon Dioxide Capture Process.

    Science.gov (United States)

    Tian, Sicong; Jiang, Jianguo; Hosseini, Davood; Kierzkowska, Agnieszka M; Imtiaz, Qasim; Broda, Marcin; Müller, Christoph R

    2015-11-01

    We propose a new class of autothermal CO2 -capture process that relies on the integration of chemical looping combustion (CLC) into calcium looping (CaL). In the new process, the heat released during the oxidation of a reduced metallic oxide is utilized to drive the endothermic calcination of CaCO3 (the regeneration step in CaL). Such a process is potentially very attractive (both economically and technically) as it can be applied to a variety of oxygen carriers and CaO is not in direct contact with coal (and the impurities associated with it) in the calciner (regeneration step). To demonstrate the practical feasibility of the process, we developed a low-cost, steel-slag-based, Fe-functionalized CO2 sorbent. Using this material, we confirm experimentally the feasibility to heat-integrate CaCO3 calcination with a Fe(II)/Fe(III) redox cycle (with regards to the heat of reaction and kinetics). The autothermal calcination of CaCO3 could be achieved for a material that contained a Ca/Fe ratio of 5:4. The uniform distribution of Ca and Fe in a solid matrix provides excellent heat transfer characteristics. The cyclic CO2 uptake and redox stability of the material is good, but there is room for further improvement. PMID:26616682

  8. Desulfurization characteristics of rapidly hydrated sorbents with various adhesive carrier particles for a semidry CFB-FGD system.

    Science.gov (United States)

    You, Changfu; Li, Yuan

    2013-03-19

    Semidry flue gas desulfurization (FGD) experiments were conducted using rapidly hydrated sorbents with four different adhesive carrier particles: circulation ash from a circulating fluidized bed boiler (CFBB circulation ash), fly ash from the first electrical field of the electrostatic precipitator of a circulating fluidized bed boiler (CFBB ESP ash), fly ash from a chain boiler (chain boiler ash), and river sand smaller than 1 mm. The influences of various adhesive carrier particles and operating conditions on the desulfurization characteristics of the sorbents were investigated, including sprayed water, reaction temperature, and the ratio of calcium to sulfur (Ca/S). The experimental results indicated that the rapidly hydrated sorbents had better desulfurization characteristics by using adhesive carrier particles which possessed better pore, adhesion, and fluidization characteristics. The desulfurization efficiency of the system increased as the reaction temperature decreased, it improved from 35% to 90% as the mass flow rate of the sprayed water increased from 0 to 10 kg/h, and it increased from 65.6% to 82.7% as Ca/S increased from 1.0 to 2.0. Based on these findings, a new semidry circulating fluidized bed (CFB)-FGD system using rapidly hydrated sorbent was developed. Using the rapidly hydrated sorbent, this system uses a cyclone separator instead of an ESP or a bag filter to recycle the sorbent particles, thereby decreasing the system flow resistance, saving investment and operating costs of the solids collection equipment. PMID:23398211

  9. Estradiol coupling to human monocyte nitric oxide release is dependent on intracellular calcium transients: evidence for an estrogen surface receptor.

    Science.gov (United States)

    Stefano, G B; Prevot, V; Beauvillain, J C; Fimiani, C; Welters, I; Cadet, P; Breton, C; Pestel, J; Salzet, M; Bilfinger, T V

    1999-10-01

    We tested the hypothesis that estrogen acutely stimulates constitutive NO synthase (cNOS) activity in human peripheral monocytes by acting on an estrogen surface receptor. NO release was measured in real time with an amperometric probe. 17beta-estradiol exposure to monocytes stimulated NO release within seconds in a concentration-dependent manner, whereas 17alpha-estradiol had no effect. 17beta-estradiol conjugated to BSA (E2-BSA) also stimulated NO release, suggesting mediation by a membrane surface receptor. Tamoxifen, an estrogen receptor inhibitor, antagonized the action of both 17beta-estradiol and E2-BSA, whereas ICI 182,780, a selective inhibitor of the nuclear estrogen receptor, had no effect. We further showed, using a dual emission microfluorometry in a calcium-free medium, that the 17beta-estradiol-stimulated release of monocyte NO was dependent on the initial stimulation of intracellular calcium transients in a tamoxifen-sensitive process. Leeching out the intracellular calcium stores abolished the effect of 17beta-estradiol on NO release. RT-PCR analysis of RNA obtained from the cells revealed a strong estrogen receptor-alpha amplification signal and a weak beta signal. Taken together, a physiological dose of estrogen acutely stimulates NO release from human monocytes via the activation of an estrogen surface receptor that is coupled to increases in intracellular calcium. PMID:10490972

  10. The reductive decomposition of calcium sulphate I. Kinetics of the apparent solid-solid reaction

    NARCIS (Netherlands)

    Kamphuis, B.; Potma, A.W.; Prins, W.; Swaaij, van W.P.M.

    1992-01-01

    The reductive decomposition of calcium sulphate by hydrogen is used for the regeneration of calcium-based atmospheric fluidized bed combustion (AFBC) SO2 sorbents. The apparent solid¿solid reaction between CaS and CaSO4, one of the steps involved in the reaction mechanism of the reductive decomposit

  11. Nanosilica supported CaO: A regenerable and mechanically hard CO2 sorbent at Ca-looping conditions

    OpenAIRE

    Sánchez-Jiménez, P.E.; Pérez-Maqueda, Luis A; J.M. Valverde

    2014-01-01

    This work presents a CO2 sorbent that may be synthesized from low-cost and widely available materials following a simple method basically consisting of impregnation of a nanostructured silica support with a saturated solution of calcium nitrate. In a first impregnation stage, the use of a stoichiometric CaO/SiO2 ratio serves to produce a calcium silicate matrix after calcination. This calcium silicate matrix acts as a thermally stable and mechanically hard support for CaO deposited on it by f...

  12. Competition of sulphation and carbonation reactions during looping cycles for CO2 capture by CaO-based sorbents.

    Science.gov (United States)

    Manovic, Vasilije; Anthony, Edward J

    2010-03-25

    Two types of sorbents are investigated here (natural limestone and highly reactive calcium aluminate pellets) to elucidate their reactivity in terms of sulphation and carbonation and determine the resulting effect on looping cycles for CO(2) capture. The sorbents are tested in a thermogravimetric analyzer (TGA) apparatus using typical synthetic flue gas mixtures containing 15% CO(2) and various concentrations of SO(2). The sulphation and carbonation conversions were determined during sulphation/carbonation/calcination cycles. The sorbent morphology and its changes were determined by means of a scanning electron microscope (SEM). The results showed that sulphation, that is, the formation of CaSO(4) at the sorbent surface, is a cumulative process with increasing numbers of reaction cycles, which hinders sorbent ability to capture CO(2). In the case of high sorbent reactivity, as determined by its morphology, the unfavorable effect of sulphation is more pronounced. Unfortunately, any increase in the temperature in the carbonation stage accelerates sulphation more than carbonation as a result of higher activation energy for the sulphation reaction. The SEM analyses showed that although sulphation and carbonation occur during cycles involving calcination, an unreacted core/partially sulphated shell sorbent particle pattern is formed. The main outcomes of this research indicate that special attention should be paid to the sulphation when more reactive and more expensive, synthetic CaO-based sorbents are used for CO(2) capture looping cycles. Desulphurization of flue gas before CO(2) capture appears to be essential because CO(2) looping cycles are so strongly affected by the presence of SO(2). PMID:20050624

  13. Fabrication and characterization of nano-HA-45S5 bioglass composite coatings on calcium-phosphate containing micro-arc oxidized CP-Ti substrates

    Science.gov (United States)

    Farnoush, Hamidreza; Muhaffel, Faiz; Cimenoglu, Huseyin

    2015-01-01

    In the present study, micro-arc oxidation (MAO) was carried out on commercially pure titanium (CP-Ti) to fabricate porous titanium oxide coatings containing calcium phosphates (CaP) at different applied voltages of 300, 330 and 360 V for 5 min. Subsequently, nano-hydroxyapatite (HA) and HA-45S5 bioglass (BG) composite were effectively coated on micro-arc oxidized substrate by electrophoretic deposition (EPD) at a constant voltage of 30 V for 120 s. The phase, structural agents, microstructure and composition of MAO interlayer and subsequent EPD coatings were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy and energy-dispersive X-ray spectroscopy, respectively. Thermal stability of the as-deposited coatings was analyzed by simultaneous differential scanning calorimetry and thermal gravimetery. The pull-off adhesion tests showed the highest bonding strength was obtained for HA-BG coating on micro-oxidized sample at 360 V. The results of potentiodynamic polarization and impedance spectroscopic measurements in simulated body fluid solution depicted that the combination of MAO treatment at 360 V and EPD of HA-BG composite could effectively increase the corrosion resistance of CP-Ti substrates.

  14. Full scale calcium bromide injection with subsequent mercury oxidation and removal within wet flue gas desulphurization system: Experience at a 700 MW coal-fired power facility

    Science.gov (United States)

    Berry, Mark Simpson

    The Environmental Protection Agency promulgated the Mercury and Air Toxics Standards rule, which requires that existing power plants reduce mercury emissions to meet an emission rate of 1.2 lb/TBtu on a 30-day rolling average and that new plants meet a 0.0002 lb/GWHr emission rate. This translates to mercury removals greater than 90% for existing units and greater than 99% for new units. Current state-of-the-art technology for the control of mercury emissions uses activated carbon injected upstream of a fabric filter, a costly proposition. For example, a fabric filter, if not already available, would require a 200M capital investment for a 700 MW size unit. A lower-cost option involves the injection of activated carbon into an existing cold-side electrostatic precipitator. Both options would incur the cost of activated carbon, upwards of 3M per year. The combination of selective catalytic reduction (SCR) reactors and wet flue gas desulphurization (wet FGD) systems have demonstrated the ability to substantially reduce mercury emissions, especially at units that burn coals containing sufficient halogens. Halogens are necessary for transforming elemental mercury to oxidized mercury, which is water-soluble. Plants burning halogen-deficient coals such as Power River Basin (PRB) coals currently have no alternative but to install activated carbon-based approaches to control mercury emissions. This research consisted of investigating calcium bromide addition onto PRB coal as a method of increasing flue gas halogen concentration. The treated coal was combusted in a 700 MW boiler and the subsequent treated flue gas was introduced into a wet FGD. Short-term parametric and an 83-day longer-term tests were completed to determine the ability of calcium bromine to oxidize mercury and to study the removal of the mercury in a wet FGD. The research goal was to show that calcium bromine addition to PRB coal was a viable approach for meeting the Mercury and Air Toxics Standards rule

  15. Sorbent utilization studies using a mini-pilot spray dryer

    Energy Technology Data Exchange (ETDEWEB)

    Keener, T.C.; Khang, S.J.; Wang, J. (Cincinnati Univ., OH (United States))

    1992-10-01

    This report stems from a program supported by the Ohio Coal Development Office, that is part of a multi-task, multi-university effort concerned with developing and enhancing the efficiency of dry'' high-sulfur flue gas scrubbing processes using calcium based sorbents. The application of spray-drying flue gas desulfurization (FGD) to sources burning Ohio coal will depend on many factors, two of which are process simplicity and flexibility, and overall cost. The ability of the system to be able to handle variations in volumetric flow SO[sub 2] concentration, and even perhaps, new regulatory requirements imposed in the future are very important In addition, the amount and characteristics of the waste produced will be a major component in the operating costs of these systems. Spray-drying FGD has been shown to have a capital, cost advantage over conventional wet scrubbing, and the method has been proven to be comparatively simple and flexible. The major disadvantage is the inability of these systems to obtain high (> 90%) S0[sub 2] removal efficiencies on flue gas from high sulfur coal sources. This is the result of chemical mass transfer and thermal limitations imposed on these systems using calcium hydroxide in a slurry as the scrubbing agent. The project 1.5 has investigated a number of novel methods to improve the performance of these systems in a mini-pilot plant spray dryer facility. The objectives of project 1.5 were the following: Perform baseline parametric testing, study the effect of additives on reactivity, and perform sorbent recycle tests.

  16. Anti-tumor Necrosis Factor Alpha (Infliximab) Attenuates Apoptosis, Oxidative Stress, and Calcium Ion Entry Through Modulation of Cation Channels in Neutrophils of Patients with Ankylosing Spondylitis.

    Science.gov (United States)

    Ugan, Yunus; Nazıroğlu, Mustafa; Şahin, Mehmet; Aykur, Mehmet

    2016-08-01

    Ankylosing Spondylitis (AS) is known to be associated with increased neutrophil activation and oxidative stress, however, the mechanism of neutrophil activation is still unclear. We have hypothesized that the antioxidant and anti-tumor necrosis factor properties of infliximab may affect intracellular Ca(2+) concentration in the neutrophils of AS patients. The objective of this study was to investigate the effects of infliximab on calcium signaling, oxidative stress, and apoptosis in neutrophils of AS patients. Neutrophils collected from ten patients with AS and ten healthy controls were used in the study. In a cell viability test, the ideal non-toxic dose and incubation time of infliximab were found as 100 μM and 1 h, respectively. In some experiments, the neutrophils were incubated with the voltage-gated calcium channel (VGCC) blockers verapamil + diltiazem (V + D) and the TRPM2 channel blocker 2-aminoethyl diphenylborinate (2-APB). Intracellular Ca(2+) concentration, lipid peroxidation, apoptosis, caspase 3, and caspase 9 values were high in neutrophils of AS patients and were reduced with infliximab treatment. Reduced glutathione level and glutathione peroxidase activity were low in the patients and increased with infliximab treatment. The intracellular Ca(2+) concentrations were low in 2-APB and V + D groups. In conclusion, the current study suggests that infliximab is useful against apoptotic cell death and oxidative stress in neutrophils of patients with AS, which seem to be dependent on increased levels of intracellular Ca(2+) through activation of TRPM2 and VGCC. PMID:26956056

  17. Inorganic sorbents for concentration of hydrogen sulfide

    International Nuclear Information System (INIS)

    Present work is devoted to application of inorganic sorbents for concentration of hydrogen sulfide. The elaboration of method is conducted under controlled concentrations of hydrogen sulphide from 1.00 til 0.01 mg/l.

  18. ROLE OF H2O2-ACTIVATED TRPM2 CALCIUM CHANNEL IN OXIDANT-INDUCED ENDOTHELIAL INJURY

    OpenAIRE

    Hecquet, Claudie M.; Malik, Asrar B.

    2009-01-01

    The transient receptor potential (melastatin) 2 (TRPM2), is an oxidant-activated nonselective cation channel, that is widely expressed in mammalian tissues including the vascular endothelium. Oxidative stress, through the generation of oxygen metabolites including H2O2, stimulates intracellular ADP-ribose formation which, in turn, opens TRPM2 channels. These channels act as an endogenous redox sensor for mediating oxidative stress/ROS-induced Ca2+ entry and the subsequent specific Ca2+-depend...

  19. Advanced Utility Mercury-Sorbent Field-Testing Program

    Energy Technology Data Exchange (ETDEWEB)

    Ronald Landreth

    2007-12-31

    This report summarizes the work conducted from September 1, 2003 through December 31, 2007 on the project entitled Advanced Utility Mercury-Sorbent Field-Testing Program. The project covers the testing at the Detroit Edison St. Clair Plant and the Duke Power Cliffside and Buck Stations. The St. Clair Plant used a blend of subbituminous and bituminous coal and controlled the particulate emissions by means of a cold-side ESP. The Duke Power Stations used bituminous coals and controlled their particulate emissions by means of hot-side ESPs. The testing at the Detroit Edison St. Clair Plant demonstrated that mercury sorbents could be used to achieve high mercury removal rates with low injection rates at facilities that burn subbituminous coal. A mercury removal rate of 94% was achieved at an injection rate of 3 lb/MMacf over the thirty day long-term test. Prior to this test, it was believed that the mercury in flue gas of this type would be the most difficult to capture. This is not the case. The testing at the two Duke Power Stations proved that carbon- based mercury sorbents can be used to control the mercury emissions from boilers with hot-side ESPs. It was known that plain PACs did not have any mercury capacity at elevated temperatures but that brominated B-PAC did. The mercury removal rate varies with the operation but it appears that mercury removal rates equal to or greater than 50% are achievable in facilities equipped with hot-side ESPs. As part of the program, both sorbent injection equipment and sorbent production equipment was acquired and operated. This equipment performed very well during this program. In addition, mercury instruments were acquired for this program. These instruments worked well in the flue gas at the St. Clair Plant but not as well in the flue gas at the Duke Power Stations. It is believed that the difference in the amount of oxidized mercury, more at Duke Power, was the difference in instrument performance. Much of the equipment was

  20. [Application of deactivating properties of some sorbents in aquaculture feed production].

    Science.gov (United States)

    Vasukevich, T A; Nitievskaya, L S

    2014-01-01

    The possibility and effectiveness of application of selective sorbents for fish feed production in aquaculture in the area exposed to the radioactive pollution were studied. The investigations of the fish feed deactivating properties with additives of ferrocyn and potassium alginate, and magnesium on whitefish fry-fingerlings and yearlings were carried out. The study has shown that the ferrocyn performance is greater than 99% regardless of the fish age. 1% ferrocyn addition to feed allows increasing the acceptable concentration of feed compo- nents polluted by the above norm cesium radionuclide up to 20 times. The alginate additives in feed provide almost double decrease in the activity of fish tissues. The optimally effective alginate dose should exceed the calcium concentration in feed up to 4 times. It was found that utilization of the feedstock (fish meal, crops and legumes, oil meal and oil cake) polluted by radionuclides is possible in combined aquaculture feed pro- duction. The application of sorbents in feed will allow increasing the amount permissible for use of the feed components polluted above the norm; ensure the radiation safety of feed and, finally, the protection of aquatic biological resources from radioactive contamination. It is shown that the sorbent additive in feed is also jus- tified in case of fish farming in closed waters affected by radioactive pollution. Feeding by mixed fodder with the sorbent additives prevents fish from radionuclide intake from natural food sources. PMID:25980288

  1. Surface characterization and corrosion behavior of calcium phosphate-base composite layer on titanium and its alloys via plasma electrolytic oxidation: A review paper.

    Science.gov (United States)

    Rafieerad, A R; Ashra, M R; Mahmoodian, R; Bushroa, A R

    2015-12-01

    In recent years, calcium phosphate-base composites, such as hydroxyapatite (HA) and carbonate apatite (CA) have been considered desirable and biocompatible coating layers in clinical and biomedical applications such as implants because of the high resistance of the composites. This review focuses on the effects of voltage, time and electrolytes on a calcium phosphate-base composite layer in case of pure titanium and other biomedical grade titanium alloys via the plasma electrolytic oxidation (PEO) method. Remarkably, these parameters changed the structure, morphology, pH, thickness and crystallinity of the obtained coating for various engineering and biomedical applications. Hence, the structured layer caused improvement of the biocompatibility, corrosion resistance and assignment of extra benefits for Osseo integration. The fabricated layer with a thickness range of 10 to 20 μm was evaluated for physical, chemical, mechanical and tribological characteristics via XRD, FESEM, EDS, EIS and corrosion analysis respectively, to determine the effects of the applied parameters and various electrolytes on morphology and phase transition. Moreover, it was observed that during PEO, the concentration of calcium, phosphor and titanium shifts upward, which leads to an enhanced bioactivity by altering the thickness. The results confirm that the crystallinity, thickness and contents of composite layer can be changed by applying thermal treatments. The corrosion behavior was investigated via the potentiodynamic polarization test in a body-simulated environment. Here, the optimum corrosion resistance was obtained for the coating process condition at 500 V for 15 min in Ringer solution. This review has been summarized, aiming at the further development of PEO by producing more adequate titanium-base implants along with desired mechanical and biomedical features. PMID:26354281

  2. Evaluation of Type I cement sorbent slurries in the U.C. pilot spray dryer facility. Final report, November 1, 1994--February 28, 1996

    Energy Technology Data Exchange (ETDEWEB)

    Keener, T.C.; Khang, S.J.

    1996-07-31

    This research was focused on evaluating hydrated cement sorbents in the U. C. pilot spray dryer. The main goal of this work was to determine the hydration conditions resulting in reactive hydrated cement sorbents. Hydration of cement was achieved by stirring or by grinding in a ball mill at either room temperature or elevated temperatures. Also, the effects of several additives were studied. Additives investigated include calcium chloride, natural diatomite, calcined diatomaceous earth, and fumed silica. The performance of these sorbents was compared with conventional slaked lime. Further, the specific surface area and pore volume of the dried SDA sorbents were measured and compared to reactivity. Bench-scale tests were performed to obtain a more detailed picture of the development of the aforementioned physical properties as a function of hydration time.

  3. Trolox-sensitive reactive oxygen species regulate mitochondrial morphology, oxidative phosphorylation and cytosolic calcium handling in healthy cells

    NARCIS (Netherlands)

    Distelmaier, F.; Valsecchi, F.; Forkink, M.; Emst-de Vries, S.E. van; Swarts, H.G.P.; Rodenburg, R.J.T.; Verwiel, E.T.P.; Smeitink, J.A.M.; Willems, P.H.G.M.; Koopman, W.J.H.

    2012-01-01

    AIMS: Cell regulation by signaling reactive oxygen species (sROS) is often incorrectly studied through extracellular oxidant addition. Here, we used the membrane-permeable antioxidant Trolox to examine the role of sROS in mitochondrial morphology, oxidative phosphorylation (OXPHOS), and cytosolic ca

  4. Role of H(2)O(2)-activated TRPM2 calcium channel in oxidant-induced endothelial injury.

    Science.gov (United States)

    Hecquet, Claudie M; Malik, Asrar B

    2009-04-01

    The transient receptor potential (melastatin) 2 (TRPM2), is an oxidant-activated non-selective cation channel that is widely expressed in mammalian tissues including the vascular endothelium. Oxidative stress, through the generation of oxygen metabolites including H(2)O(2), stimulates intracellular ADP-ribose formation which, in turn, opens TRPM2 channels. These channels act as an endogenous redox sensor for mediating oxidative stress/ROS-induced Ca(2+) entry and the subsequent specific Ca(2+)-dependent cellular reactions such as endothelial hyperpermeability and apoptosis. This review summarizes recent findings on the mechanism by which oxidants induce TRPM2 activation, the role of these channels in the signalling vascular endothelial dysfunctions, and the modulation of oxidant-induced TRPM2 activation by PKCalpha and phospho-tyrosine phosphates L1. PMID:19350103

  5. ROLE OF H2O2-ACTIVATED TRPM2 CALCIUM CHANNEL IN OXIDANT-INDUCED ENDOTHELIAL INJURY

    Science.gov (United States)

    Hecquet, Claudie M.; Malik, Asrar B.

    2013-01-01

    The transient receptor potential (melastatin) 2 (TRPM2), is an oxidant-activated nonselective cation channel, that is widely expressed in mammalian tissues including the vascular endothelium. Oxidative stress, through the generation of oxygen metabolites including H2O2, stimulates intracellular ADP-ribose formation which, in turn, opens TRPM2 channels. These channels act as an endogenous redox sensor for mediating oxidative stress/ROS-induced Ca2+ entry and the subsequent specific Ca2+-dependent cellular reactions such as endothelial hyper-permeability and apoptosis. This review summarizes recent findings on the mechanism by which oxidants induce TRPM2 activation, the role of these channels in the signaling vascular endothelial dysfunctions, and the modulation of oxidant-induced TRPM2 activation by PKCα and phospho-tyrosine phosphates L1. PMID:19350103

  6. The alpha hemolysin of Escherichia Coli power the metabolism oxidative of neutrophils human beings in response to the peptide chemotactic FMLP: comparison with the ionophore of calcium A23187

    International Nuclear Information System (INIS)

    The calcium ionophore ionomycin primes polymorphonuclear leukocytes (PMN) for increased superoxide production upon stimulation with the chemotactic peptide FMLP (Helman Finkel, T. et al J Biol Chem 1987; 262: 12589-12596) In this investigation we assessed the effect of PMN priming with either alpha hemolysin (AH) or the calcium ionophore A23187, both of which increase intracellular calcium, on the oxidative metabolism of PMN (as measured by chemiluminescence) in response to secondary stimulation with FMLP. Both A23187 and AH priming increased, the luminol-enhanced chemiluminescence in response to secondary stimulation with FMLP, indicating overstimulation of PMLP oxidative metabolism. Additional experiments using lucigenin as chemiluminescence enhancer showed that A23187, but not AH priming of PMN, increased superoxide release in a manner similar to that reported for ionomycin. These results are discussed in reference to infectious processes involving hemolytic E. coli (Author)

  7. High-Yield Method for Isolation and Culture of Endothelial Cells from Rat Coronary Blood Vessels Suitable for Analysis of Intracellular Calcium and Nitric Oxide Biosynthetic Pathways

    Science.gov (United States)

    Nistri, Silvia; Mazzetti, Luca; Failli, Paola

    2002-01-01

    We describe here a method for isolating endothelial cells from rat heart blood vessels by means of coronary microperfusion with collagenase. This methods makes it possible to obtain high amounts of endothelial cells in culture which retain the functional properties of their in vivo counterparts, including the ability to uptake fluorescently-labeled acetylated low-density lipoproteins and to respond to vasoactive agents by modulating intracellular calcium and by upregulating intrinsic nitric oxide generation. The main advantages of our technique are: (i) good reproducibility, (ii) accurate sterility that can be maintained throughout the isolation procedure and (iii) high yield of pure endothelial cells, mainly due to microperfusion and temperature-controlled incubation with collagenase which allow an optimal distribution of this enzyme within the coronary vascular bed. PMID:12734571

  8. A decontamination system for chemical weapons agents using a liquid solution on a solid sorbent

    International Nuclear Information System (INIS)

    A decontamination system for chemical warfare agents was developed and tested that combines a liquid decontamination reagent solution with solid sorbent particles. The components have fewer safety and environmental concerns than traditional chlorine bleach-based products or highly caustic solutions. The liquid solution, based on Decon GreenTM, has hydrogen peroxide and a carbonate buffer as active ingredients. The best solid sorbents were found to be a copolymer of ethylene glycol dimethacrylate and n-lauryl methacrylate (Polytrap 6603 Adsorber); or an allyl methacrylate cross-linked polymer (Poly-Pore E200 Adsorber). These solids are human and environmentally friendly and are commonly used in cosmetics. The decontaminant system was tested for reactivity with pinacolyl methylphosphonofluoridate (Soman, GD), bis(2-chloroethyl)sulfide (Mustard, HD), and S-(2-diisopropylaminoethyl) O-ethyl methylphosphonothioate (VX) by using NMR Spectroscopy. Molybdate ion (MoO4-2) was added to the decontaminant to catalyze the oxidation of HD. The molybdate ion provided a color change from pink to white when the oxidizing capacity of the system was exhausted. The decontaminant was effective for ratios of agent to decontaminant of up to 1:50 for VX (t1/2 ≤ 4 min), 1:10 for HD (t1/2 1/2 < 2 min). The vapor concentrations of GD above the dry sorbent and the sorbent with decontamination solution were measured to show that the sorbent decreased the vapor concentration of GD. The E200 sorbent had the additional advantage of absorbing aqueous decontamination solution without the addition of an organic co-solvent such as isopropanol, but the rate depended strongly on mixing for HD

  9. Calcium carboorthovanadate - a new compound with the apa

    International Nuclear Information System (INIS)

    Data on calcium carboorthovanadate, Ca10(VO4)6CO3, a new compound with an appatite structure based on calcium orthovanadate, are reported. The synthesis has been conducted in a stoichiometric mixture of finely ground calcium carbonate and calcium orthovanadate. It is found that calcium carboorthovanadate belongs to the hexagonal syngony and has an apatite structure. An analysis of the infrared spectra of initial compounds and calcium carboorthovanadate confirmed the presence of carbonate (CO3)2- and orthovanadate (VO4)3 groupings in the latter. On heating in air, beginning with 450 deg C calcium carboorthovanadate decomposes at a slow rate into calcium oxide, calcium orthovanadate, and carbon dioxide

  10. Effect of ZnO on phase emergence, microstructure and surface modifications of calcium phosphosilicate glass/glass-ceramics having iron oxide

    International Nuclear Information System (INIS)

    The effect of ZnO on phase emergence and microstructure properties of glass and glass-ceramics with composition 25SiO2-50CaO-15P2O5-(10 - x)Fe2O3-xZnO (where x = 0, 2, 5, 7 mol%) has been studied. They have been characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). Surface modifications of these glass-ceramics in simulated body fluid have been studied using Fourier transform infrared reflection spectroscopy (FTIR), XPS and SEM. Results have shown a decrease in the fraction of non-bridging oxygen with increase in zinc oxide content. Emergence of crystalline phases in glass-ceramics at different heat treatment temperatures was studied using XRD. When glass is heat treated at 800 deg. C calcium phosphate, hematite and magnetite are developed as major phases in the glass-ceramics samples with ZnO up to 5 mol%. In addition to these, calcium silicate (Ca3Si2O7) phase is also observed when glass is heat treated at 1000 deg. C. The microstructure of the glass-ceramics heat treated at 800 deg. C exhibits the formation of nano-size (40-50 nm) grains. On heat treatment at 1000 deg. C crystallites grow to above 50 nm size and more than one phase are observed in the microstructure. The formation of thin flake-like structure with coarse particles is observed at high zinc oxide concentration (x = 7 mol%). In vitro studies have shown the surface modifications and formation of Ca-P-rich layer on the glass-ceramics when immersed in simulated body fluids (SBF) for different durations. The bioactive response was found to depend on ZnO content.

  11. IEA low NOx combustion project Stage III. Low NOx combustion and sorbent injection demonstration projects. V.2

    International Nuclear Information System (INIS)

    This report summarizes the main results from an IES project concerning the demonstration of low-NOx combustion and sorbent injection as techniques for the control of NOx and SOx emissions from pulverized coal fired utility boilers. The project has built upon information generated in two previous stages of activity, where NOx and SOx control processes were evaluated at both fundamental and pilot-scales. The concept for this stage of the project was for a unique collaboration, where the participating countries (Canada, Denmark and Sweden, together with the United States) have pooled information from full scale boiler demonstrations of low-NOx burner and sorbent injection technologies, and have jointly contributed to establishing a common basis for data evaluation. Demonstration testing was successfully carried out on five wall-fired commercial boiler systems which ranged in size from a 20 MW thermal input boiler used for district heating, up to a 300 MW electric utility boiler. All of these units were fired on high-volatile bituminous coals with sulfur contents ranging from 0.6-3.2 percent. At each site the existing burners were either modified or replaced to provide for low-NOx combustion, and provisions were made to inject calcium based sorbent materials into the furnace space for SO2 emission control. The results of sorbent injection testing showed moderate levels of SO2 removal which ranged from approximately 15 to 55 percent at an injected calcium to sulfur molar ratio to 2.0 and with boiler operation at nominal full load. Sulfur capture was found to depend upon the combined effects of parameters such as: sorbent type and reactivity; peak sorbent temperature; coal sulfur content; and the thermal characteristics of the boilers. (8 refs., 58 figs., 6 tabs.)

  12. Phosphorus removal from aqueous solution using iron coated natural and engineered sorbents

    Energy Technology Data Exchange (ETDEWEB)

    Boujelben, N. [Laboratoire Eau Energie et Environnement, departement de genie geologique, Ecole Nationale d' Ingenieurs de Sfax, BP W 3038 Sfax (Tunisia)], E-mail: nesrine.boujelben@tunet.tn; Bouzid, J.; Elouear, Z. [Laboratoire Eau Energie et Environnement, departement de genie geologique, Ecole Nationale d' Ingenieurs de Sfax, BP W 3038 Sfax (Tunisia); Feki, M. [Unite de chimie industrielle I, Ecole Nationale d' Ingenieurs de Sfax, BP W 3038 Sfax (Tunisia); Jamoussi, F. [Laboratoire de Georessources CERTE BP 95, 2050 Hamam-Lif (Tunisia); Montiel, A. [Societe Anonyme de Gestion des Eaux de Paris, 9 rue Schoelcher, 75675 Paris Cedex 14 (France)

    2008-02-28

    New filtration materials covered with metallic oxides are good adsorbents for both cation and anion forms of pollutants. Sfax is one of the most important industrial towns in Tunisia. Its phosphate manufacture in particular is causing considerable amounts of water pollution. Therefore, there is a need to find out a new way of getting rid of this excessive phosphate from water. This work is aimed to examining the potential of three sorbent materials (synthetic iron oxide coated sand (SCS), naturally iron oxide coated sand (NCS) and iron oxide coated crushed brick (CB)) for removing phosphate ions from aqueous solutions. According to our literature survey CB was not used as adsorbent previously. Phosphate ions are used here as species model for the elimination of other similar pollutants (arsenates, antimonates). Optical microscope and scanning electron microscope (SEM) analyses were used to investigate the surface properties and morphology of the coated sorbents. Infra-red spectroscopy and X-ray diffraction techniques were also used to characterize the sorbent structures. Results showed that iron coated crushed brick possess more micro pores and a higher surface area owing to its clay nature. The comparative sorption of PO{sub 4}{sup 3-} from aqueous solutions by SCS, CB and NCS was investigated by batch experiments. The estimated optimum pH of phosphate ion retention for the considered sorbents was 5. The equilibrium data were analysed using the Langmuir and Freundlich isotherms. The sorption capacities of PO{sub 4}{sup 3-} at pH 5 were 1.5 mg/g for SCS, 1.8 mg/g for CB and 0.88 mg/g for NCS. The effect of temperature on sorption phenomenon was also investigated. The results indicated that adsorption is an endothermic process for phosphate ions removal. This study demonstrates that all the considered sorbents can be used as an alternative emerging technology for water treatment without any side effect or treatment process alteration.

  13. Effects of calcium and phosphate on uranium(IV) oxidation. Comparison between nanoparticulate uraninite and amorphous UIV–phosphate

    Energy Technology Data Exchange (ETDEWEB)

    Latta, Drew E. [Argonne National Lab. (ANL), Argonne, IL (United States); Kemner, Kenneth M. [Argonne National Lab. (ANL), Argonne, IL (United States); Mishra, Bhoopesh [Argonne National Lab. (ANL), Argonne, IL (United States); Illinois Inst. of Technology, Chicago, IL (United States); Boyanov, Maxim I. [Argonne National Lab. (ANL), Argonne, IL (United States); Bulgarian Academy of Sciences, Sofia (Bulgaria)

    2016-02-01

    The mobility of uranium in subsurface environments depends strongly on its redox state, with UIV phases being significantly less soluble than UVI minerals. This study compares the oxidation kinetics and mechanisms of two potential products of UVI reduction in natural systems, a nanoparticulate UO2 phase and an amorphous UIV–Ca–PO4 analog to ningyoite (CaUIV(PO4)2·1–2H2O). The valence of U was tracked by X-ray absorption near-edge spectroscopy (XANES), showing similar oxidation rate constants for UIVO2 and UIV–phosphate in solutions equilibrated with atmospheric O2 and CO2 at pH 7.0 (kobs,UO2 = 0.17 ± 0.075 h-1 vs. kobs,UIVPO4 = 0.30 ± 0.25 h-1). Addition of up to 400 μM Ca and PO4 decreased the oxidation rate constant by an order of magnitude for both UO2 and UIV–phosphate. The intermediates and products of oxidation were tracked by electron microscopy, powder X-ray diffraction (pXRD), and extended X-ray absorption fine-structure spectroscopy (EXAFS). In the absence of Ca or PO4, the product of UO2 oxidation is Na–uranyl oxyhydroxide (under environmentally relevant concentrations of sodium, 15 mM NaClO4 and low carbonate concentration), resulting in low concentrations of dissolved UVI (<2.5 × 10-7 M). Oxidation of UIV–phosphate produced a Na-autunite phase (Na2(UO2)PO4·xH2O), resulting in similarly low dissolved U concentrations (<7.3 × 10-8 M). When Ca and PO4 are present in the solution, the EXAFS data and the solubility of the UVI phase resulting from oxidation of UO2 and UIV–phosphate are consistent with the precipitation of Na-autunite. Bicarbonate extractions and Ca K-edge X-ray absorption spectroscopy of oxidized solids indicate the formation of a Ca–UVI–PO4 layer on the UO2 surface and suggest a passivation layer mechanism for the decreased rate of UO2 oxidation in the presence of Ca and PO4. Interestingly, the extractions were unable to remove all of the oxidized U from partially oxidized UO2 solids, suggesting that oxidized U is

  14. Effects of calcium and phosphate on uranium(IV) oxidation: Comparison between nanoparticulate uraninite and amorphous UIV-phosphate

    Science.gov (United States)

    Latta, Drew E.; Kemner, Kenneth M.; Mishra, Bhoopesh; Boyanov, Maxim I.

    2016-02-01

    The mobility of uranium in subsurface environments depends strongly on its redox state, with UIV phases being significantly less soluble than UVI minerals. This study compares the oxidation kinetics and mechanisms of two potential products of UVI reduction in natural systems, a nanoparticulate UO2 phase and an amorphous UIV-Ca-PO4 analog to ningyoite (CaUIV(PO4)2·1-2H2O). The valence of U was tracked by X-ray absorption near-edge spectroscopy (XANES), showing similar oxidation rate constants for UIVO2 and UIV-phosphate in solutions equilibrated with atmospheric O2 and CO2 at pH 7.0 (kobs,UO2 = 0.17 ± 0.075 h-1 vs. kobs,UIVPO4 = 0.30 ± 0.25 h-1). Addition of up to 400 μM Ca and PO4 decreased the oxidation rate constant by an order of magnitude for both UO2 and UIV-phosphate. The intermediates and products of oxidation were tracked by electron microscopy, powder X-ray diffraction (pXRD), and extended X-ray absorption fine-structure spectroscopy (EXAFS). In the absence of Ca or PO4, the product of UO2 oxidation is Na-uranyl oxyhydroxide (under environmentally relevant concentrations of sodium, 15 mM NaClO4 and low carbonate concentration), resulting in low concentrations of dissolved UVI (<2.5 × 10-7 M). Oxidation of UIV-phosphate produced a Na-autunite phase (Na2(UO2)PO4·xH2O), resulting in similarly low dissolved U concentrations (<7.3 × 10-8 M). When Ca and PO4 are present in the solution, the EXAFS data and the solubility of the UVI phase resulting from oxidation of UO2 and UIV-phosphate are consistent with the precipitation of Na-autunite. Bicarbonate extractions and Ca K-edge X-ray absorption spectroscopy of oxidized solids indicate the formation of a Ca-UVI-PO4 layer on the UO2 surface and suggest a passivation layer mechanism for the decreased rate of UO2 oxidation in the presence of Ca and PO4. Interestingly, the extractions were unable to remove all of the oxidized U from partially oxidized UO2 solids, suggesting that oxidized U is distributed between

  15. Oxidation of RyR2 Has a Biphasic Effect on the Threshold for Store Overload-Induced Calcium Release.

    Science.gov (United States)

    Waddell, Helen M M; Zhang, Joe Z; Hoeksema, Katie J; McLachlan, Julia J; McLay, Janet C; Jones, Peter P

    2016-06-01

    At the single-channel level, oxidation of the cardiac ryanodine receptor (RyR2) is known to activate and inhibit the channel depending on the level of oxidation. However, the mechanisms through which these changes alter the activity of RyR2 in a cellular setting are poorly understood. In this study, we determined the effect of oxidation on a common form of RyR2 regulation; store overload-induced Ca(2+) release (SOICR). We found that oxidation resulted in concentration and time-dependent changes in the activation threshold for SOICR. Low concentrations of the oxidant H2O2 resulted in a decrease in the threshold for SOICR, which led to an increase in SOICR events. However, higher concentrations of H2O2, or prolonged exposure, reversed these changes and led to an increase in the threshold for SOICR. This increase in the threshold for SOICR in most cells was to such an extent that it led to the complete inhibition of SOICR. Acute exposure to high concentrations of H2O2 led to an initial decrease and then increase in the threshold for SOICR. In the majority of cells the increased threshold could not be reversed by the application of the reducing agent dithiothreitol. Therefore, our data suggest that low levels of RyR2 oxidation increase the channel activity by decreasing the threshold for SOICR, whereas high levels of RyR2 oxidation irreversibly increase the threshold for SOICR leading to an inhibition of RyR2. Combined, this indicates that oxidation regulates RyR2 by the same mechanism as phosphorylation, methylxanthines, and mutations, via changes in the threshold for SOICR. PMID:27276257

  16. The antimicrobial efficiency of silver activated sorbents

    Science.gov (United States)

    Đolić, Maja B.; Rajaković-Ognjanović, Vladana N.; Štrbac, Svetlana B.; Rakočević, Zlatko Lj.; Veljović, Đorđe N.; Dimitrijević, Suzana I.; Rajaković, Ljubinka V.

    2015-12-01

    This study is focused on the surface modifications of the materials that are used for antimicrobial water treatment. Sorbents of different origin were activated by Ag+-ions. The selection of the most appropriate materials and the most effective activation agents was done according to the results of the sorption and desorption kinetic studies. Sorption capacities of selected sorbents: granulated activated carbon (GAC), zeolite (Z), and titanium dioxide (T), activated by Ag+-ions were following: 42.06, 13.51 and 17.53 mg/g, respectively. The antimicrobial activity of Ag/Z, Ag/GAC and Ag/T sorbents were tested against Gram-negative bacteria E. coli, Gram-positive bacteria S. aureus and yeast C. albicans. After 15 min of exposure period, the highest cell removal was obtained using Ag/Z against S. aureus and E. coli, 98.8 and 93.5%, respectively. Yeast cell inactivation was unsatisfactory for all three activated sorbents. The antimicrobial pathway of the activated sorbents has been examined by two separate tests - Ag+-ions desorbed from the activated surface to the aqueous phase and microbial cell removal caused by the Ag+-ions from the solid phase (activated surface sites). The results indicated that disinfection process significantly depended on the microbial-activated sites interactions on the modified surface. The chemical state of the activating agent had crucial impact to the inhibition rate. The characterization of the native and modified sorbents was performed by X-ray diffraction technique, X-ray photoelectron spectroscopy and scanning electron microscope. The concentration of adsorbed and released ions was determined by inductively coupled plasma optical emission spectroscopy and mass spectrometry. The antimicrobial efficiency of activated sorbents was related not only to the concentration of the activating agent, but moreover on the surface characteristics of the material, which affects the distribution and the accessibility of the activating agent.

  17. Highly stable and regenerable Mn-based/SBA-15 sorbents for desulfurization of hot coal gas

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, F.M. [Department of Chemistry, Tianjin University, Tianjin 300072 (China); Liu, B.S., E-mail: bingsiliu@tju.edu.cn [Department of Chemistry, Tianjin University, Tianjin 300072 (China); Zhang, Y.; Guo, Y.H.; Wan, Z.Y.; Subhan, Fazle [Department of Chemistry, Tianjin University, Tianjin 300072 (China)

    2012-09-30

    Highlights: Black-Right-Pointing-Pointer A series of mesoporous Cu{sub x}Mn{sub y}O{sub z}/SBA-15 sorbents were fabricated for hot coal gas desulfurization. Black-Right-Pointing-Pointer 1Cu9Mn/SBA-15 sorbent with high breakthrough sulfur capacity is high stable and regenerable. Black-Right-Pointing-Pointer Utilization of SBA-15 constrained the sintering and pulverization of sorbents. - Abstract: A series of mesoporous xCuyMn/SBA-15 sorbents with different Cu/Mn atomic ratios were prepared by wet impregnation method and their desulfurization performance in hot coal gas was investigated in a fixed-bed quartz reactor in the range of 700-850 Degree-Sign C. The successive nine desulfurization-regeneration cycles at 800 Degree-Sign C revealed that 1Cu9Mn/SBA-15 presented high performance with durable regeneration ability due to the high dispersion of Mn{sub 2}O{sub 3} particles incorporated with a certain amount of copper oxides. The breakthrough sulfur capacity of 1Cu9Mn/SBA-15 observed 800 Degree-Sign C is 13.8 g S/100 g sorbents, which is remarkably higher than these of 40 wt%LaFeO{sub 3}/SBA-15 (4.8 g S/100 g sorbents) and 50 wt%LaFe{sub 2}O{sub x}/MCM-41 (5.58 g S/100 g sorbents) used only at 500-550 Degree-Sign C. This suggested that the loading of Mn{sub 2}O{sub 3} active species with high thermal stability to SBA-15 support significantly increased sulfur capacity at relatively higher sulfidation temperature. The fresh and used xCuyMn/SBA-15 sorbents were characterized by means of BET, XRD, XPS, XAES, TG/DSC and HRTEM techniques, confirmed that the structure of the sorbents remained intact before and after hot coal gas desulfurization.

  18. Reuse of partially sulphated CFBC ash as an SO{sub 2} sorbent

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Y.; Jia, L.; Anthony, E.J. [Natural Resources Canada, Ottawa, ON (Canada). CANMET Energy; Nobili, M.; Telesca, A. [Basilicata Univ., Potenza (Italy). Dept. of Environmental Engineering and Physics; Montagnaro, F. [Naples Univ., Naples (Italy). Dept. of Chemistry

    2010-06-15

    Ash produced from circulating fluidized bed combustion (CFBC) boilers typically contains large amounts of unreacted calcium oxide (CaO) when limestone is added into the combustor for in situ removal of sulphur dioxide (SO{sub 2}). This paper reported on a study that evaluated the reactivation of partially sulphated ash obtained from an industrial circulating fluidized bed combustion (CFBC) boiler by hydration with liquid water and steam. A pilot-scale mini-CFBC was used to evaluate the results of reactivation on the bed ash by hydrating with liquid water and admixtures of sodium carbonate (Na{sub 2}CO{sub 3}) in solution or as powder. Re-sulphation tests on the hydrated samples were performed in a Cahn 1000 thermogravimetric analyzer (TGA) at 850 degrees C for 90 minutes in a simulated flue gas environment with sulphur dioxide (SO{sub 2}) concentration at 5000 ppm. Re-sulphation was carried out on unhydrated ash at the same conditions used in the baseline test. The TGA results showed that although liquid water and steam successfully hydrate and reactivate the unreacted CaO in the bed ash, the treated ashes sulphated to widely different extents. Attempts to reactivate fly ash with hydration failed, but the fly ash by itself was extremely reactive. When the treated ash was re-injected into the combustor with the fuel, the effect on SO{sub 2} removal efficiency was negligible if Na{sub 2}CO{sub 3} was added as powder. Doping with aqueous solution improved SO{sub 2} removal, but to a lesser extent than if only water hydration was used. Increasing the amount of water to reactivate the ash did not improve the sulphur capture capacity in the mini-CFBC. It was concluded that reactivation by water is the most practical way to reuse the partially sulphated bed ash as a sulphur sorbent. 21 refs., 7 tabs., 3 figs.

  19. Effect of sorbent hydration on the average activity of CaO in a Ca-looping system

    Energy Technology Data Exchange (ETDEWEB)

    Arias, B.; Grasa, G.S.; Abanades, J.C. [CSIC, Oviedo (Spain)

    2010-10-01

    It is well known that the solid sorbents used in calcium looping CO{sub 2} capture systems experience a reduction in carrying capacity with the number of cycles. Several sorbent reactivation schemes have been proposed as means of overcoming this deactivation process. This work analyzes the integration of a reactivation process in a Ca-looping cycle by means of a hydration reactor. The mass balances involved in this three-reactor systems must then be solved in order to evaluate the effect of the different variables on the average activity of the sorbent. The positive impact of reactivation by hydration (i.e. average increase in activity of the sorbent arriving at the carbonator) is discussed in conjunction with the negative impacts on the overall operation of the system (e.g. steam consumption, etc.) and on the large reactivation reactors. Two different scenarios employing different degrees of hydration have been evaluated. The results obtained show that steam is used more efficiently when only a small fraction of the circulating solids is hydrated to a high degree. Moreover, the performance of the sorbent reactivation step is better when low make up flows of limestone are used.

  20. Performance of Zn-Fe-Mn/MCM-48 sorbents for high temperature H2S removal and analysis of regeneration process

    Science.gov (United States)

    Huang, Z. B.; Liu, B. S.; Wang, F.; Amin, R.

    2015-10-01

    MCM-48 was synthesized using a rapid and facile process at room temperature. A series of 50%Zn-Fe-Mn/MCM-48 sorbents were prepared and their performance of hot coal gas desulfurization was investigated. High breakthrough sulfur capacity (13.2 g-S/100 g sorbent) and utilization (66.1%) of 50%1Zn2Fe2Mn/MCM-48 sorbent at 550 °C was achieved. The characterization results of XRD, BET, TPR and FT-IR revealed that MCM-48 had excellent thermal stability at less than 700 °C, ZnMn2O4 and (Mn, Zn)Fe2O4 were mainly active particles in fresh sorbents which were highly dispersed on support. The MCM-48 mesoporous structure remained intact after eight successive desulfurization/regeneration cycles. The regeneration process of 50%1Zn2Fe2Mn/MCM-48 sorbent was analyzed, it indicated that the breakthrough sulfur capacity decline of sorbent was due to the migration of Zn onto the sorbent surface and Zn accumulated on the surface and vaporized to the exterior from the surface. In the TPO test, the oxidation of Zn was different for 50%Zn/MCM-48 at 700 °C. It revealed that the temperature of regeneration for ZnO sorbent should be higher than 700 °C.

  1. Hepatic calcium efflux during cytochrome P-450-dependent drug oxidations at the endoplasmic reticulum in intact liver.

    Science.gov (United States)

    Sies, H; Graf, P; Estrela, J M

    1981-06-01

    During metabolism of (type I) drugs by cytochrome P-450-dependent monooxygenase of the endoplasmic reticulum, the NADPH/NADP+ ratio in rat liver selectively decreases to approximately one-half of the control values, whereas the NADH/NAD+ ratio remains practically unaffected [Sies, H. & Brauser, B. (1970) Eur. J. Biochem. 15, 521-540]. In view of the observations with isolated mitochondria [Lehninger, A. L., Vercesi, A. & Bababunmi, E. A. (1978) Proc. Natl. Acad. Sci. USA 75, 1690-1694] of stimulated Ca2+ efflux upon nicotinamide nucleotide oxidation, the selective oxidation of NADPH in cytosol and mitochondria during drug oxidations was considered a useful experimental tool for the determination of whether the oxidation of NADPH or of NADH is responsible for Ca2+ efflux. With perfused livers from phenobarbital-treated rats, Ca2+ efflux was demonstrated, amounting to 8 nmol/min per gram of liver (wet weight), with aminopyrine, ethylmorphine, or hexobarbital as drug substrates. Drug-associated Ca2+ release was diminished when the inhibitor metyrapone was also present, or when drug oxidation was suppressed during N2 anoxia or in the presence of antimycin A in livers from fasted rats. Ca2+ efflux was elicited also by infusion of the thiol oxidant diamide, and by t-butyl hydroperoxide. However whereas Ca2+ efflux elicited by these compounds was restricted upon addition of the thiol dithioerythritol, there was little, if any, sensitivity of the drug-associated Ca2+ efflux to the thiol. Further mitochondrial oxidation of NADPH by addition of ammonium chloride had no effect on drug-associated Ca2+ efflux. Prior addition of the alpha-agonist phenylephrine suppressed the Ca2+ release by drug addition. While the molecular mechanism involved in Ca2+ efflux from liver mitochondria and from hepatocytes as well as the regulatory significance are not yet known, it is concluded from the present experiments that in case of nicotinamide nucleotide-linked Ca2+ efflux the oxidation of

  2. Chronic hyperammonemia reduces the activity of neuronal nitric oxide synthase in cerebellum by altering its localization and increasing its phosphorylation by calcium-calmodulin kinase II.

    Science.gov (United States)

    El-Mlili, Nisrin; Rodrigo, Regina; Naghizadeh, Bahareh; Cauli, Omar; Felipo, Vicente

    2008-08-01

    Impaired function of the glutamate-nitric oxide-cGMP pathway contributes to cognitive impairment in hyperammonemia and hepatic encephalopathy. The mechanisms by which hyperammonemia impairs this pathway remain unclear. Understanding these mechanisms would allow designing clinical treatments for cognitive deficits in hepatic encephalopathy. The aims of this work were: (i) to assess whether chronic hyperammonemia in vivo alters basal activity of neuronal nitric oxide synthase (nNOS) in cerebellum and/or its activation in response to NMDA receptor activation and (ii) to analyse the molecular mechanisms by which hyperammonemia induces these alterations. It is shown that hyperammonemia reduces both basal activity of nNOS and its activation following NMDA receptor activation. Reduced basal activity is because of increased phosphorylation in Ser847 (by 69%) which reduces basal activity of nNOS by about 40%. Increased phosphorylation of nNOS in Ser847 is because of increased activity of calcium-calmodulin-dependent protein kinases (CaMKII) which in turn is because of increased phosphorylation at Thr286. Inhibiting CaMKII with KN-62 normalizes phosphorylation of Ser847 and basal NOS activity in hyperammonemic rats, returning to values similar to controls. Reduced activation of nNOS in response to NMDA receptor activation in hyperammonemia is because of altered subcellular localization of nNOS, with reduced amount in post-synaptic membranes and increased amount in the cytosol. PMID:18498443

  3. Introducing surface-modified ordered mesoporous carbon as a promising sorbent for extraction of N-nitrosamines.

    Science.gov (United States)

    Lashgari, Maryam; Lee, Hian Kee

    2016-11-01

    The extraction and pre-concentration of N-nitrosamines (NAs) before their determination are mainly achieved by carbonaceous sorbents. However, the non-polar or relatively less polar NAs are strongly absorbed on the carbonaceous surface of the sorbent, leading to low extraction recoveries. In the present study, for the first time, CMK-3 and surfacemodified CMK-3 (O-CMK-3) were used to extract NAs from water. The CMK-3 surface was modified by oxidative treatment and different carboxylic groups were attached to create a hydrophilic/hydrophobic balance on the inert surface of the carbonaceous sorbent. The proposed sorbents were compared with 10 different kinds of commercial carbonaceous sorbents for the micro-solid phase extraction of eight NAs possessing a wide range of polarities. The best extraction results for both polar and non-polar NAs were obtained using O-CMK-3. Specifically, significant enhancements in the extraction of the nonpolar NAs were observed. For instance, extraction of up to 27.67 and 2.32 times greater were observed for N-nitrosodiphenylamine, and N-nitrosodimethylamine respectively, when O-CMK-3 was used instead of coconut charcoal sorbent. PMID:27451033

  4. Rapid reduction of titanium dioxide nano-particles by reduction with a calcium reductant

    OpenAIRE

    Kikuchi, Tatsuya; Yoshida, Masumi; Matsuura, Shiki; Natsui, Shungo; Tsuji, Etsuji; Habazaki, Hiroki; Suzuki, Ryosuke O.

    2014-01-01

    Micro-, submicron-,andnano-scaletitaniumdioxideparticleswerereducedbyreductionwithametallic calcium reductantincalciumchloridemoltensaltat1173K,andthereductionmechanismoftheoxides by thecalciumreductantwasexplored.Theseoxideparticles,metalliccalciumasareducingagent,and calcium chlorideasamoltensaltwereplacedinatitaniumcrucibleandheatedunderanargon atmosphere. Titaniumdioxidewasreducedtometallictitaniumthroughacalciumtitanateandlower titanium oxide,andthematerialsweresinteredtog...

  5. Sorbent Structural Testing on Carbon Dioxide Removal Sorbents for Advanced Exploration Systems

    Science.gov (United States)

    Watson, David; Knox, James C.; West, Phillip; Bush, Richard

    2016-01-01

    Long term space missions require carbon dioxide removal systems that can function with minimal downtime required for maintenance, low power consumption and maximum efficiency for CO2 removal. A major component of such a system are the sorbents used for the CO2 and desiccant beds. Sorbents must not only have adequate CO2 and H2O removal properties, but they must have the mechanical strength to prevent structural breakdown due to pressure and temperature changes during operation and regeneration, as well as resistance to breakdown due to moisture in the system from cabin air. As part of the studies used to select future CO2 sorbent materials, mechanical tests are performed on various zeolite sorbents to determine mechanical performance while dry and at various humidified states. Tests include single pellet crush, bulk crush and attrition tests. We have established a protocol for testing sorbents under dry and humid conditions, and previously tested the sorbents used on the International Space Station carbon dioxide removal assembly. This paper reports on the testing of a series of commercial sorbents considered as candidates for use on future exploration missions.

  6. Long Life Moving-Bed Zinc Titanate Sorbent

    International Nuclear Information System (INIS)

    The objective of this work was to develop and test long-life sorbents for hot gas cleanup. Specifically, we measured the sulfur loading at space velocities typically used for absorption of H2S and regenerated the sorbent with diluted air for multiple cycles. Based on the experimental results, we prepared a conceptual design of the sorbent-fabrication system, and estimated the cost of sorbent production and of sulfur removal

  7. INTERACTION BETWEEN SO2 FROM FLUE GAS AND SORBENT PARTICLES IN DRY FGD PROCESSES

    Institute of Scientific and Technical Information of China (English)

    Haiying; Qi; Changfu; You; Xuchang; Xu

    2005-01-01

    Among the technologies to control SO2 emission from coal-fired boilers, the dry flue gas desulphurization (FGD) method,with appropriate modifications, has been identified as a candidate for realizing high SO2 removal efficiency to meet both technical and economic requirements, and for making the best quality byproduct gypsum as a useful additive for improving alkali soil.Among the possible modifications two major factors have been selected for study:(1) favorable chemical reaction kinetics at elevated temperatures and the sorbent characteristics;(2) enhanced diffusion of SO2 to the surface and within the pores of sorbent particles that are closely related to gas-solid two-phase flow patterns caused by flue gas and sorbent particles in the reactor.To achieve an ideal pore structure, a sorbent was prepared through hydration reaction by mixing lime and fly ash collected from bag house of power plants to form a slurry, which was first dewatered and then dried. The dry sorbent was found capable of rapid conversion of 70% of its calcium content at 700 ℃, reaching a desulphurization efficiency of over 90% at a Ca/S ratio of 1.3.Experiments confirmed that the diffusion effect of SO2 is an important factor and that gas-solid two-phase flow plays a key role to mixing and contact between SO2 and sorbent particles. For designing the FDG reactor, a new theoretical drag model was developed by combination of CFD with the Energy Minimization Multi-Scale (EMMS) theory for dense fluidization systems. This new drag model was first verified by comparing calculated and measured drag values, and was then implemented in simulation of gas-solid two-phase flow in two circulating fluidized beds with different sizes and flow parameters. One riser has diameter and height of 0.15 m×3 m and another one 0.2 m×14.2 m. Their superficial gas velocities The results show that not only the static pressure drop along the riser height, but also radial distributions of particle volume fraction have

  8. Encapsulated liquid sorbents for carbon dioxide capture

    Science.gov (United States)

    Vericella, John J.; Baker, Sarah E.; Stolaroff, Joshuah K.; Duoss, Eric B.; Hardin, James O.; Lewicki, James; Glogowski, Elizabeth; Floyd, William C.; Valdez, Carlos A.; Smith, William L.; Satcher, Joe H.; Bourcier, William L.; Spadaccini, Christopher M.; Lewis, Jennifer A.; Aines, Roger D.

    2015-02-01

    Drawbacks of current carbon dioxide capture methods include corrosivity, evaporative losses and fouling. Separating the capture solvent from infrastructure and effluent gases via microencapsulation provides possible solutions to these issues. Here we report carbon capture materials that may enable low-cost and energy-efficient capture of carbon dioxide from flue gas. Polymer microcapsules composed of liquid carbonate cores and highly permeable silicone shells are produced by microfluidic assembly. This motif couples the capacity and selectivity of liquid sorbents with high surface area to facilitate rapid and controlled carbon dioxide uptake and release over repeated cycles. While mass transport across the capsule shell is slightly lower relative to neat liquid sorbents, the surface area enhancement gained via encapsulation provides an order-of-magnitude increase in carbon dioxide absorption rates for a given sorbent mass. The microcapsules are stable under typical industrial operating conditions and may be used in supported packing and fluidized beds for large-scale carbon capture.

  9. Manganese-doped lanthanum calcium titanate as an interconnect for flat-tubular solid oxide fuel cells

    Science.gov (United States)

    Raeis Hosseini, Niloufar; Sammes, Nigel Mark; Chung, Jong Shik

    2014-01-01

    A cost-effective screen-printing process is developed to fabricate a dense layer of solid oxide fuel cell (SOFC) interconnect material. A series of lanthanum-manganese-doped CaTiO3 perovskite oxides (La0.4Ca0.6Ti1-xMnxO3-δ; (x = 0.0, 0.2, 0.4, 0.6)) powders is successfully synthesized using an EDTA-citrate method and co-sintered as an interconnect material on an extruded porous anode substrate in a flat-tubular solid oxide fuel cell. All samples adopt a single perovskite phase after calcination at 950 °C for 5 h. High-temperature XRD confirms that the perovskite structure is thermally stable in both oxidizing and reducing conditions. The highest electrical conductivity occurs when x = 0.6; at 12.20 S cm-1 and 2.70 S cm-1 under oxidizing and reducing conditions. The thermal expansion coefficient of La0.4Ca0.6Ti0.4Mn0.6O3 is 10.76 × 10-6 K-1, which closely matches that of 8 mol% yttria-stabilized zirconia. Chemical compatibility of samples and their reduction stability are verified at the operating temperature. The power density and area-specific resistance value at x = 0.6 is 208 mW cm-1 and 1.23 Ω cm2 at 800 °C under open circuit voltage, and 200 mV signal amplitude under 3% humidified hydrogen and air respectively. This performance indicates that La0.4Ca0.6Ti0.4Mn0.6O3-δ has potential for use as interconnect in a flat tubular SOFC.

  10. FURNACE INJECTION OF ALKALINE SORBENTS FOR SULFURIC ACID REMOVAL

    Energy Technology Data Exchange (ETDEWEB)

    Gary M. Blythe

    2004-01-01

    The objective of this project has been to demonstrate the use of alkaline reagents injected into the furnace of coal-fired boilers as a means of controlling sulfuric acid emissions. The project was co-funded by the U.S. DOE National Energy Technology Laboratory under Cooperative Agreement DE-FC26-99FT40718, along with EPRI, the American Electric Power Company (AEP), FirstEnergy Corporation, the Tennessee Valley Authority, and Carmeuse North America. Sulfuric acid controls are becoming of increased interest for coal-fired power generating units for a number of reasons. In particular, sulfuric acid can cause plant operation problems such as air heater plugging and fouling, back-end corrosion, and plume opacity. These issues will likely be exacerbated with the retrofit of selective catalytic reduction (SCR) for NOX control, as SCR catalysts are known to further oxidize a portion of the flue gas SO{sub 2} to SO{sub 3}. The project tested the effectiveness of furnace injection of four different magnesium-based or dolomitic alkaline sorbents on full-scale utility boilers. These reagents were tested during one- to two-week tests conducted on two FirstEnergy Bruce Mansfield Plant (BMP) units. One of the sorbents tested was a magnesium hydroxide slurry byproduct from a modified Thiosorbic{reg_sign} Lime wet flue gas desulfurization process. The other three sorbents are available commercially and include dolomite, pressure-hydrated dolomitic lime, and commercially available magnesium hydroxide. The dolomite reagent was injected as a dry powder through out-of-service burners. The other three reagents were injected as slurries through air-atomizing nozzles inserted through the front wall of the upper furnace. After completing the four one- to two-week tests, the most promising sorbents were selected for longer-term (approximately 25-day) full-scale tests on two different units. The longer-term tests were conducted to confirm sorbent effectiveness over extended operation on two

  11. Alkaline sorbent injection for mercury control

    Science.gov (United States)

    Madden, Deborah A.; Holmes, Michael J.

    2003-01-01

    A mercury removal system for removing mercury from combustion flue gases is provided in which alkaline sorbents at generally extremely low stoichiometric molar ratios of alkaline earth or an alkali metal to sulfur of less than 1.0 are injected into a power plant system at one or more locations to remove at least between about 40% and 60% of the mercury content from combustion flue gases. Small amounts of alkaline sorbents are injected into the flue gas stream at a relatively low rate. A particulate filter is used to remove mercury-containing particles downstream of each injection point used in the power plant system.

  12. Desulfurization Sorbents for Transport-Bed Applications

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Raghubir P.; Turk, Brian S.; Vierheilig, Albert A.

    1997-07-01

    This project extends the prior work on the development of fluidizable zinc titanate particles using a spray-drying technique to impart high reactivity and attrition resistance. The specific objectives are: (1) To develop highly reactive and attrition-resistant zinc titanate sorbents in 40- to 150-{micro}m particle size range for transport reactor applications; (2) To transfer sorbent production technology to private sector; and (3) To provide technical support to Sierra Pacific Clean Coal Technology Demonstration plant and FETC's Hot-Gas Desulfurization Process Development Unit (PDU), both employing a transport reactor system.

  13. Desulfurization Sorbents for Transport-Bed Applications

    International Nuclear Information System (INIS)

    This project extends the prior work on the development of fluidizable zinc titanate particles using a spray-drying technique to impart high reactivity and attrition resistance. The specific objectives are: (1) To develop highly reactive and attrition-resistant zinc titanate sorbents in 40- to 150-(micro)m particle size range for transport reactor applications; (2) To transfer sorbent production technology to private sector; and (3) To provide technical support to Sierra Pacific Clean Coal Technology Demonstration plant and FETC's Hot-Gas Desulfurization Process Development Unit (PDU), both employing a transport reactor system

  14. Topical Report 5: Sorbent Performance Report

    Energy Technology Data Exchange (ETDEWEB)

    Krutka, Holly; Sjostrom, Sharon

    2011-05-31

    ADA-ES has completed an extensive sorbent screening program funded primarily through DOE NETL cooperative agreement DE-NT0005649 with support from EPRI and industry cost-share participants. Tests were completed on simulated and actual flue gas. The overall project objective is to address the viability and accelerate development of a solid-based postcombustion CO2 capture technology that can be retrofit to the existing fleet of coal-fired power plants. An important component of the viability assessment was to evaluate the state of development of sorbents and measure key performance characteristics under realistic operating conditions.

  15. Potassium and calcium application ameliorates growth and oxidative homeostasis in salt-stressed indian mustard (brassica juncea) plants

    International Nuclear Information System (INIS)

    The effect of potassium (K) and calcium (Ca) on growth and antioxidant defence system of salt-stressed Indian mustard plants was studied. Twenty-day-old Indian mustard plants grown hydroponically in Hoagland growth medium were randomly divided into five groups. To served as control and did not receive any additional K or Ca (except that present in Hoagland solution), T1 received 150 mM NaCl, T2 was given an additional doze of 6 mM K, T3 was given 5.6 mM Ca as additional doze, while as T4 received a combination of 150 mM NaCl + 6 mM K + 5.6 mM Ca. The response of the plants was studied ten days after treatment. Salt stress inhibited growth parameters including biomass, chlorophyll content, protein content and NR activity. Membrane damage was induced by the salt treatment with a concurrent increase in antioxidant defence system and proline content. Individual application of K and Ca mitigated the negative influence of the stress with the maximum alleviating potential exhibited by the combined application of these nutrients. Results obtained on real time expression of genes encoding enzymatic antioxidants (SOD, APX, CAT and GR), NR and proline supported our findings with biochemical assays. We conclude from the study that maintaining high K and Ca levels may serve as an effective means for regulating the growth and productivity of Indian mustard plants under saline conditions. (author)

  16. Insight into elastic behavior of calcium silicate hydrated oxide (C–S–H) under pressure and composition effect

    International Nuclear Information System (INIS)

    The present work relates to the study of structural and elastic properties of Tobermorite 11 Å as a function of external pressure and composition in terms of calcium to silicon ratio. Basing on the lattice dynamics method, the main aim of this work is precisely to shed light, for the first time, on the high pressure structural phase transition in Tobermorite 11 Å and the possible correlation with some elastic quantities. In order to check the transferability of the potentials used we have, additionally, performed a single calculation based on the density functional theory (DFT) for a pressure of 15 GPa in the case of Ca/Si = 1. The variation of the unit cell parameters with pressure indicates that Tobermorite 11 Å undergoes a structural instability around 15 GPa along b-axis and around 20 GPa along a-axis which is confirmed from our calculations of X-Rays diffraction patterns at various pressure values. We have also observed the anisotropic character of the Tobermorite structure for both cases (Ca/Si = 1 and Ca/Si = 0.83). Our results show that around 20 GPa an important change appears in the elastic behaviour of Tobermorite. As pressure increases the calculated elastic quantities for Ca/Si = 1 became closer to those evaluated for Ca/Si = 0.83, which may stimulate further experimental and theoretical research on the matter.

  17. Thermodynamics of the conversion of calcium and magnesium fluorides to the parent metal oxides and hydrogen fluoride

    Energy Technology Data Exchange (ETDEWEB)

    West, M.H.; Axler, K.M.

    1997-02-01

    The authors have used thermodynamic modeling to examine the reaction of calcium fluoride (CaF{sub 2}) and magnesium fluoride (MgF{sub 2}) with water (H{sub 2}O) at elevated temperatures. The calculated, equilibrium composition corresponds to the global free-energy minimum for the system. Optimum, predicted reaction temperatures and reactant mole ratios are reported for the recovery of hydrogen fluoride (HF), a valuable industrial feedstock. Complete conversion of MgF{sub 2} is found at 1,000 C and a ratio of 40 moles of H{sub 2}O per 1 mole of MgF{sub 2}. For CaF{sub 2}, temperatures as high as 1,400 C are required for complete conversion at a corresponding mole ratio of 40 moles of H{sub 2}O per 1 mole of CaF{sub 2}. The authors discuss the presence of minor chemical constituents as well as the stability of various potential container materials for the pyrohydrolysis reactions at elevated temperatures. CaF{sub 2} and MgF{sub 2} slags are available as wastes at former uranium production facilities within the Department of Energy Complex and other facilities regulated by the Nuclear Regulatory Commission. Recovery of HF from these wastes is an example of environmental remediation at such facilities.

  18. Involvement of Nitric Oxide on Calcium Mobilization and Arachidonic Acid Pathway Activation during Platelet Aggregation with different aggregating agonists

    OpenAIRE

    Banerjee, Debipriya; Mazumder, Sahana; Kumar Sinha, Asru

    2016-01-01

    Platelet aggregation by different aggregating agonists is essential in the normal blood coagulation process, the excess of which caused acute coronary syndrome (ACS). In all cases, the activation of arachidonic acid by cycloxygenase was needed for the synthesis of thromboxane A2 (TXA2) but the mechanism of arachidonic acid release in platelets remains obscure. Studies were conducted to determine the role of nitric oxide (NO), if any, on the release of arachidonic acid in platelets. The cytoso...

  19. Calcium(II)(3) (3,5-Diisopropylsalicylate)(6)(H(2)O)(6) Activates Nitric Oxide Synthase: An Accounting for its Action in Decreasing Platelet Aggregation.

    Science.gov (United States)

    Donham, D C; Sorenson, J R

    2000-01-01

    Purposes of these studies were first; to determine whether or not Calcium(II)(3) (3,5- diisopropylsalicylate)(6)(H(2)O)(6) [Ca(II)(3)(3,5-DIPS)(6)], a lipophilic calcium complex, could decrease activated-platelet aggregation, and second; to determine whether or not it is plausible that Ca(II)(3)(3,5-DIPS)(6) decreases activated-platelet aggregation by facilitating the synthesis of Nitric Oxide (NO) by Nitric Oxide Synthase (NOS). The influence of Ca(II)(3)(3,5-DIPS)(6) on the initial rate of activated-platelet aggregation was determined by measuring the decrease in rate of increase in transmission at 550 nm for a suspension of Thrombin-CaCl(2) activated platelets following the addition of 0, 50, 100, 250, or 500 muM Ca(II)(3)(3,5-DIPS)(6). To establish that the Ca(lI)(3)(3,5- DIPS)(6)-mediated decrease in aggregation was due to activation of NOS, the effect of L-NMMA, an inhibitor of NOS, on the inhibition of platelet aggregation by Ca(II)(3)(3,5-DIPS)(6) was determined using a suspension of activated platelets contaimng 0 or 250 muM Ca(II)(3)(3,5-DIPS)(6) without or with 1 mM L-NMMA. An in vitro Bovine Brain NOS reaction mixture, containing CaCl(2) for the activation of Phosphodiesterase-3' ,5'-Cyclic Nucleotide Activator required for the activation of NOS, was used to determine whether or not Ca(II)(3)(3,5-DIPS)(6) could be used as a substitute for the addition of Ca. The decrease in absorbance at 340 nm, lambda maximum for NADPH, was measured to determine NOS activity following the addition of NOS to the complete reaction mixture containing either CaCl(2), Ca(II)(3)(3,5-DIPS)(6), or neither Ca compound. Increasing the concentration of Ca(II)(3)(3,5-DIPS)(6) caused a concentration related decrease in activated platelet aggregation. The addition of L-NMMA to activated platelets, in the absence of Ca(II)(3)(3,5-DIPS)(6), caused a 129% increase in initial rate of platelet aggregation. The initial rate of platelet aggregation decreased 74% with the addition of 250 mu

  20. Changes in the level of cytosolic calcium, nitric oxide and nitric oxide synthase activity during platelet aggregation: an in vitro study in platelets from normal subjects and those with cirrhosis

    Indian Academy of Sciences (India)

    Sam Annie-JeyachristYn; Arumugam Geetha; Rajagopal Surendran

    2008-03-01

    Variceal bleeding due to abnormal platelet function is a well-known complication of cirrhosis. Nitric oxide-related stress has been implicated in the pathogenesis of liver cirrhosis. In the present investigation, we evaluated the level of platelet aggregation and concomitant changes in the level of platelet cytosolic calcium (Ca2+), nitric oxide (NO) and NO synthase (NOS) activity in liver cirrhosis. The aim of the present study was to investigate whether the production of NO by NOS and level of cytosolic Ca2+ influence the aggregation of platelets in patients with cirrhosis of the liver. Agonist-induced aggregation and the simultaneous changes in the level of cytosolic Ca2+, NO and NOS were monitored in platelets of patients with cirrhosis. Platelet aggregation was also measured in the presence of the eNOS inhibitor, diphenylene iodinium chloride (DIC). The level of agonist-induced platelet aggregation was significantly low in the platelets of patients with cirrhosis compared with that in platelets from normal subjects. During the course of platelet aggregation, concomitant elevation in the level of cytosolic Ca2+ was observed in normal samples, whereas the elevation was not significant in platelets of patients with cirrhosis. A parallel increase was observed in the levels of NO and NOS activity. In the presence of the eNOS inhibitor, platelet aggregation was enhanced and accompanied by an elevated calcium level. The inhibition of platelet aggregation in liver cirrhosis might be partly due to greater NO formation by eNOS. Defective Ca2+ release from the internal stores to the cytosol may account for inhibition of aggregation of platelets in cirrhosis. The NO-related defective aggregation of platelets in patients with cirrhosis found in our study is of clinical importance, and the underlying mechanism of such changes suggests a possible therapeutic strategy with cell-specific NO blockers.

  1. NIR fluorescence spectroscopic investigations of Er{sup 3+}-ions doped borate based tellurium calcium zinc niobium oxide glasses

    Energy Technology Data Exchange (ETDEWEB)

    Ravi, O. [Department of Instrumentation, Sri Venkateswara University, Tirupati 517502 (India); Dhoble, S.J. [Department of Physics, RTM Nagpur University, Nagpur 440033 (India); Ramesh, B.; Devarajulu, G. [Department of Physics, Sri Venkateswara University, Tirupati 517502 (India); Reddy, C. Madhukar [Department of Physics, AP Model School, Yerravaripalem 517194 (India); Linganna, K. [Department of Physics, Sri Venkateswara University, Tirupati 517502 (India); Reddy, G. Rajasekhar [Department of Instrumentation, Sri Venkateswara University, Tirupati 517502 (India); Raju, B. Deva Prasad, E-mail: drdevaprasadraju@gmail.com [Department of Physics, Sri Venkateswara University, Tirupati 517502 (India); Department of Future Studies, Sri Venkateswara University, Tirupati 517502 (India)

    2015-08-15

    A series of Er{sup 3+} ions doped tellurium calcium zinc niobium borate glasses were prepared by the melt quenching technique. The prepared samples were investigated by optical absorption and near infrared fluorescence spectroscopic studies. The obtained Judd–Ofelt intensity parameters Ω{sub λ} (λ=2, 4 and 6) were determined through experimental and calculated oscillator strengths obtained from absorption spectra and their results are studied and compared with reported literature. The stark-level energies of {sup 4}I{sub 13/2} excited and {sup 4}I{sub 15/2} ground states were evaluated by using both the absorption and emission measurements. The effect of Er{sup 3+} ion concentration on the emission intensity of {sup 4}I{sub 13/2}→{sup 4}I{sub 15/2} transition was discussed. Intense and broad 1.53 µm infrared fluorescence is observed at 980 nm diode laser excitation. Photoluminescence (PL) and its decay behavior studies were carried out for the transition {sup 4}I{sub 13/2}→{sup 4}I{sub 15/2} at 1.53 µm emission. The broad emission together with higher values of the bandwidth (81 nm), stimulated emission cross-section (32.25×10{sup −22} cm{sup 2}) and lifetime (530 µs for 1.0 mol% of Er{sup 3+}) of level {sup 4}I{sub 13/2} make these glasses attractive for broadband amplifiers. From the analysis of spectroscopic data, the present glass is a prospective photonic material for practical applications in the visible and NIR region. - Highlights: • In this study we prepared TCZNB glasses doped with Er{sup 3+} ions. • Glasses are characterized with absorption, emission and lifetime analysis. • Judd–Ofelt theory is used to calculate radiative properties. • TCZNB glasses could be used as NIR lasers.

  2. NIR fluorescence spectroscopic investigations of Er3+-ions doped borate based tellurium calcium zinc niobium oxide glasses

    International Nuclear Information System (INIS)

    A series of Er3+ ions doped tellurium calcium zinc niobium borate glasses were prepared by the melt quenching technique. The prepared samples were investigated by optical absorption and near infrared fluorescence spectroscopic studies. The obtained Judd–Ofelt intensity parameters Ωλ (λ=2, 4 and 6) were determined through experimental and calculated oscillator strengths obtained from absorption spectra and their results are studied and compared with reported literature. The stark-level energies of 4I13/2 excited and 4I15/2 ground states were evaluated by using both the absorption and emission measurements. The effect of Er3+ ion concentration on the emission intensity of 4I13/2→4I15/2 transition was discussed. Intense and broad 1.53 µm infrared fluorescence is observed at 980 nm diode laser excitation. Photoluminescence (PL) and its decay behavior studies were carried out for the transition 4I13/2→4I15/2 at 1.53 µm emission. The broad emission together with higher values of the bandwidth (81 nm), stimulated emission cross-section (32.25×10−22 cm2) and lifetime (530 µs for 1.0 mol% of Er3+) of level 4I13/2 make these glasses attractive for broadband amplifiers. From the analysis of spectroscopic data, the present glass is a prospective photonic material for practical applications in the visible and NIR region. - Highlights: • In this study we prepared TCZNB glasses doped with Er3+ ions. • Glasses are characterized with absorption, emission and lifetime analysis. • Judd–Ofelt theory is used to calculate radiative properties. • TCZNB glasses could be used as NIR lasers

  3. Formation of (FexMn(2-x))O3 solid solution and high sulfur capacity properties of Mn-based/M41 sorbents for hot coal gas desulfurization.

    Science.gov (United States)

    Zhang, Y; Liu, B S; Zhang, F M; Zhang, Z F

    2013-03-15

    Several MCM-41 materials were synthesized at different conditions by hydrothermal procedure using cheap and easily available industrial water glass as silica source. Fe doped manganese-based oxide/MCM-41 sorbents were prepared by a sol-gel method. The effects of loadings of metal oxide, Fe/Mn molar ratios over MCM-41 and reaction temperature on the performance of sorbent for hot coal gas desulfurization were investigated. Various techniques such as BET, XRD, XPS, LRS and HRTEM were used to characterize the sorbents. The result indicated Fe(3+) ions could occupy a position of Mn(3+) in cubic lattice of Mn2O3 and the (FexMn2-x)O3 solid solution is mainly active phase of sorbent. Moreover, the result of nine successive sulfurization-regeneration cycles of sorbent showed high sulfur adsorption capacity and endurable stability of FeMn4Ox/MCM-41 for H2S removal. PMID:23337625

  4. Design of a sorbent to enhance reactive adsorption of hydrogen sulfide.

    Science.gov (United States)

    Wang, Long-Jiang; Fan, Hui-Ling; Shangguan, Ju; Croiset, Eric; Chen, Zhongwei; Wang, Hui; Mi, Jie

    2014-12-10

    A series of novel zinc oxide-silica composites with three-dimensionally ordered macropores (3DOM) structure were synthesized via colloidal crystal template method and used as sorbents for hydrogen sulfide (H2S) removal at room temperature for the first time. The performances of the prepared sorbents were evaluated by dynamic breakthrough testing. The materials were characterized before and after adsorption using scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen adsorption, X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS). It was found that the composite with 3DOM structure exhibited remarkable desulfurization performance at room temperature and the enhancement of reactive adsorption of hydrogen sulfide was attributed to the unique structure features of 3DOM composites; high surface areas, nanocrystalline ZnO and the well-ordered interconnected macroporous with abundant mesopores. The introduction of silica could be conducive to support the 3DOM structure and the high dispersion of zinc oxide. Moisture in the H2S stream plays a crucial role in the removal process. The effects of Zn/Si ratio and the calcination temperature of 3DOM composites on H2S removal were studied. It demonstrated that the highest content of ZnO could reach up to 73 wt % and the optimum calcination temperature was 500 °C. The multiple adsorption/regeneration cycles showed that the 3DOM ZnO-SiO2 sorbent is stable and the sulfur capacity can still reach 67.4% of that of the fresh sorbent at the fifth cycle. These results indicate that 3DOM ZnO-SiO2 composites will be a promising sorbent for H2S removal at room temperature. PMID:25382853

  5. Trace-Metal Scavenging from Biomass Syngas with Novel High-Temperature Sorbents

    Energy Technology Data Exchange (ETDEWEB)

    Gale, Thomas K. [Southern Research Inst., Birmingham, AL (United States); Walsh, Pete M. [Southern Research Inst., Birmingham, AL (United States)

    2007-03-21

    downstream equipment from damage. Finally, the high-temperature sorbent technology would be expanded to look at the role that these sorbents play in relation to tars and acid gases, which are the other significant pollutants within syngas. In addition to the technology development work described above, all of the information obtained in this work was to be incorporated into a syngas speciation model, which would allow direct prediction of transformations that occur in syngas as it passes from the gasifier and the sorbent-injection section and through the barrier filters. Unfortunately, Congressional budget cuts prevented most of this work from being accomplished. Hopefully, additional funds will be provided to this work in the future, which will allow its completion. However, at the halting point of this project, the following has been accomplished. A major initial objective of the project was accomplished, which was to determine whether or not high-temperature sorbents found to work within vitiated air might also work in an inert environment. Kaolinite, one of the sorbents previously investigated as a high-temperature sorbent for incinerators, was found to effectively capture potassium. In addition, while previous work on short-time (i.e., 1 to 2 seconds) dispersed-phase reactions found that sorbent utilization was limited to two metal oxide species captured for every one aluminosilicate crystal structure, the present investigation found that many times higher insoluble metal/sorbent capture ratios were obtained. This result not only suggests that small additions of sorbent might be highly effective, but the fact that the products were insoluble (in part due to the temperature of sorbent injection, i.e., < 1500 °F) may be an indication that the products are unlikely to react with, corrode, or otherwise damage the candle-filter elements. There has been little work on the capture of potassium metal vapor by high-temperature sorbents, prior to this work. The fact that

  6. Cross-flow, filter-sorbent-catalyst for particulate, SO{sub 2} and NO{sub x} control. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Benedek, K. [Little (Arthur D.), Inc., Cambridge, MA (United States); Flytzani-Stephanopoulos, M. [Massachusetts Inst. of Tech., Cambridge, MA (United States)

    1994-05-01

    This report describes work performed on a new concept for integrated pollutant control: An active filter comprised of layered, gas permeable membranes that act as a particle filter, an SO{sub 2} sorbent, and a NO{sub x}, reduction catalyst. The focus of the research program documented in this final report is the development of the sorbent/catalyst materials that are the basis of such an emission control system. The device investigated in this program will simultaneously remove particulates, SO{sub 2} and NO{sub x}, from combustion exhaust gases. Sulfur dioxide capture and nitrogen oxide reduction are achieved with a reg le, mixed-metal oxide sorbent-catalyst. The device is a filter with layered walls: A small-pore layer is a barrier to particles, and a macroporus active layer is a SO{sub 2} sorbent and a catalyst for the selective catalytic reduction of NO{sub x}. The small-pore layer could be an inert ceramic that provides structural strength to the unit and protects the active (sorbent-catalyst) material from abrasion or contamination from fly ash particles. We have found that 95--100% removal efficiency of SO{sub 2} and 60--90% removal of NO{sub x}, is achievable with the use of mixed-metal oxide sorbent-catalysts in the device. The ceramic filters are barriers to particles and typically have removal efficiencies of 99.9%.

  7. Involvement of Nitric Oxide on Calcium Mobilization and Arachidonic Acid Pathway Activation during Platelet Aggregation with different aggregating agonists.

    Science.gov (United States)

    Banerjee, Debipriya; Mazumder, Sahana; Kumar Sinha, Asru

    2016-03-01

    Platelet aggregation by different aggregating agonists is essential in the normal blood coagulation process, the excess of which caused acute coronary syndrome (ACS). In all cases, the activation of arachidonic acid by cycloxygenase was needed for the synthesis of thromboxane A2 (TXA2) but the mechanism of arachidonic acid release in platelets remains obscure. Studies were conducted to determine the role of nitric oxide (NO), if any, on the release of arachidonic acid in platelets. The cytosolic Ca(2+) was visualized and quantitated by fluorescent spectroscopy by using QUIN-2. NO was measured by methemoglobin method. Arachidonic acid was determined by HPLC. TXA2 was measured as ThromboxaneB2 (TXB2) by ELISA. Treatment of platelets in platelet-rich plasma (PRP) with different aggregating agents resulted in the inhibition of nitric oxide synthase (NOS) which inhibited the production of NO synthesis and increased TXA2 synthesis. Furthermore, the treatment of washed PRP with different platelet aggregating agents resulted in the increase of [Ca(2+)] in nM ranges. In contrast, the pre-treatment of washed PRP with aspirin increased platelet NO level and inhibited the Ca(2+) mobilization and TXA2 synthesis. These results indicated that the aggregation of platelets by different aggregating agonists was caused by the cytosolic Ca(2+) mobilization due to the inhibition of NOS. PMID:27127451

  8. Niobium doped lanthanum calcium ferrite perovskite as a novel electrode material for symmetrical solid oxide fuel cells

    Science.gov (United States)

    Kong, Xiaowei; Zhou, Xiaoliang; Tian, Yu; Wu, Xiaoyan; Zhang, Jun; Zuo, Wei

    2016-09-01

    Development of cost-effective and efficient electrochemical catalysts for the fuel cells electrode is of prime importance to emerging renewable energy technologies. Here, we report for the first time the novel La0.9Ca0.1Fe0.9Nb0.1O3-δ (LCFNb) perovskite with good potentiality for the electrode material of the symmetrical solid oxide fuel cells (SSOFC). The Sc0.2Zr0.8O2-δ (SSZ) electrolyte supported symmetrical cells with impregnated LCFNb and LCFNb/SDC (Ce0.8Sm0.2O2-δ) electrodes achieve relatively high power outputs with maximum power densities (MPDs) reaching up to 392 and 528.6 mW cm-2 at 850 °C in dry H2, respectively, indicating the excellent electro-catalytic activity of LCFNb towards both hydrogen oxidation and oxygen reduction. Besides, the MPDs of the symmetrical cells with LCFNb/SDC composite electrodes in CO and syngas (CO: H2 = 1:1) are almost identical to those in H2, implying that LCFNb material has similar catalytic activities to carbon monoxide compared with hydrogen. High durability in both H2, CO and syngas during the short term stability tests for 50 h are also obtained, showing desirable structure stability, and carbon deposition resistance of LCFNb based electrodes. The present results indicate that the LCFNb perovskite with remarkable cell performance is a promising electrode material for symmetrical SOFCs.

  9. Calcium Carbonate

    Science.gov (United States)

    ... before being swallowed; do not swallow them whole. Drink a full glass of water after taking either the regular or chewable tablets or capsules. Some liquid forms of calcium carbonate must be shaken well before use.Do not ...

  10. Calcium Electroporation

    DEFF Research Database (Denmark)

    Frandsen, Stine Krog; Gibot, Laure; Madi, Moinecha;

    2015-01-01

    BACKGROUND: Calcium electroporation describes the use of high voltage electric pulses to introduce supraphysiological calcium concentrations into cells. This promising method is currently in clinical trial as an anti-cancer treatment. One very important issue is the relation between tumor cell kill...... efficacy-and normal cell sensitivity. METHODS: Using a 3D spheroid cell culture model we have tested the effect of calcium electroporation and electrochemotherapy using bleomycin on three different human cancer cell lines: a colorectal adenocarcinoma (HT29), a bladder transitional cell carcinoma (SW780......), and a breast adenocarcinoma (MDA-MB231), as well as on primary normal human dermal fibroblasts (HDF-n). RESULTS: The results showed a clear reduction in spheroid size in all three cancer cell spheroids three days after treatment with respectively calcium electroporation (p<0.0001) or...

  11. Calcium Calculator

    Science.gov (United States)

    ... Latvia - Lebanon - Libya - Lithuania - Luxembourg - Macedonia, Republic of - Malaysia - Malta - Mexico - Moldova - Morocco - Netherlands - New Zealand - Nigeria - ... and Statistics Popular content Calcium content of common foods What is Osteoporosis? The Board Introduction to Bone ...

  12. A perspective on sorbents: responding to a bunker oil spill

    International Nuclear Information System (INIS)

    Some practical guidelines for the selection of sorbents for use in oil spill cleanup are provided. Sorbents may be classified as selective or oleophilic, and non-selective or universal. Oleophilic sorbents are water-repelling, i.e. they will soak up oil spills and leave water behind. Universal sorbents will soak up most liquids. Sorbents come in such forms as booms, pads, socks, pillows, and loose particulates for spills on land. A case history involving a spill of Bunker C oil in a drainage ditch was provided to illustrate the variety of sorbents that may have to be employed to contain a particular spill. Since unexpected situations during a cleanup effort are the rule more than the exception, it is wise to use a sorbent supplier company that can fulfill a variety of spill response needs

  13. Trichloroethylene decomposition and in-situ dry sorption of Cl-products by calcium oxides prepared from hydrated limes.

    Science.gov (United States)

    Gotoh, Yoshimi; Iwata, Goichi; Choh, Kyaw; Kubota, Mitsuhiro; Matsuda, Hitoki

    2011-10-01

    A comparison of CaOs produced by calcining two types of hydrated lime and calcium carbonate was made for decomposition of trichloroethylene and in-situ dry sorption of the decomposed Cl-products using a lab-scale gas flow type tubular packed bed reactor. About 20 mg of CaO sample was mixed with about 2 g of Al2O3 particles and packed in the reactor and allowed to react with a flowing standard gas containing 500 ppm of C2HCl3 (N2 balance) at 673 and 873 K, under the condition that the reaction of CaO with C2HCl3 might be completed within a few hours. It was found that no thermal decomposition of C2HCl3 at or below 673 K was observed in a reactor packed only with Al2O3 particles. However, a considerable amount of decomposition of C2HCl3 was obtained in a reactor packed with CaO and Al2O3, even at 673 K. For 1 mol of CaO prepared by calcining highly reactive Ca(OH)2 at 673 K, decomposition of 0.42 mol of C2HCl3 and in-situ absorption product of 0.53 mol of CaCl2 were obtained. At 873 K, about 46% of C2HCl3 was thermally decomposed. The total amount of C2HCl3 decomposed in CaO-Al2O3 particle bed at 873 K became nearly twice larger than that at 673 K. For 1 mol of CaO prepared by calcining highly reactive Ca(OH)2 at 873 K, decomposition of 0.59 mol of C2HCl3 and in-situ absorption product of 0.67 mol of CaCl2 were obtained. Small amounts of C2Cl2, C2Cl4, CCl4, etc. were detected during decomposition of C2HCl3 at 673 and 873 K. It was recognized that the data on decomposition of C2HCl3 as well as in-situ dry sorption of Cl-products in CaO particle bed were correlated with specific surface area of the CaO employed. PMID:21821273

  14. Study on calcium precursors for CaO preparation to capture CO2 at high temperature%CaO高温吸附捕集CO2-制备CaO的钙基前驱体材料筛选

    Institute of Scientific and Technical Information of China (English)

    张明明; 计超; 孙泽; 汪瑾; 李平; 于建国

    2012-01-01

    价格低廉的CaO材料在高温下能高效吸附捕集CO2气体,被认为是碳减排的有效方法之一.然而,CaO长时间循环碳酸化/煅烧解吸后,其CO2的化学吸附容量下降,稳定性较差,限制了该材料的工业应用.本文采用天然钙源(牡蛎壳和方解石等)和化学试剂(醋酸钙)为钙基前驱材料制备CaO.采用扫描电子显微镜(SEM),X射线衍射仪(XRD)和氮气吸附仪等手段对制备的CaO材料进行形貌和物理结构的分析表征;在高温和模拟的烟道气氛条件下(10% CO2和90% N2),采用热重分析仪测量CaO吸附CO2的能力和长时间循环碳酸化/煅烧解吸后的稳定性.我们经过与目前所报道的其他钙基吸附材料进行比较,并结合钙基前驱材料的市场价格,发现CaO(醋酸钙)的CO2吸附能力和稳定性较为理想,醋酸钙在高温烟气捕碳方面具有非常好的应用前景.%As an abundant and cheap material, calcium oxide (CaO) is an efficient sorbent for CO2 capture at high temperature. The carbonation/calcination loop of CaO/CaCO3 is an effective process for CO2 capture and storage (CCS). However, both the gradual decline of the CO2 capture capacity and the poor stability, because of the pore filling and pore closure at the high calcination temperature, limit the industrial application of calcium-based sorbents. In this paper, study on calcium precursors was carried out in order to obtain CaO sorbents to capture CO2 with high efficiency. The candidate materials include seashell materials (oyster shells), natural minerals (calcite) and chemical reagents (calcium acetate hydrate). Oyster shell powder and calcite powder were analyzed by XRD, and CaO sorbents prepared from various precursors were characterized by nitrogen physisorption apparatus. The fresh CaO sorbents and CaO after multiple cycles to capture CO2 were characterized by scanning electron microscopy (SEM). The capture CO2 capability and the stability of CaO sorbents were

  15. Puerarin activates endothelial nitric oxide synthase through estrogen receptor-dependent PI3-kinase and calcium-dependent AMP-activated protein kinase

    International Nuclear Information System (INIS)

    The cardioprotective properties of puerarin, a natural product, have been attributed to the endothelial nitric oxide synthase (eNOS)-mediated production of nitric oxide (NO) in EA.hy926 endothelial cells. However, the mechanism by which puerarin activates eNOS remains unclear. In this study, we sought to identify the intracellular pathways underlying eNOS activation by puerarin. Puerarin induced the activating phosphorylation of eNOS on Ser1177 and the production of NO in EA.hy926 cells. Puerarin-induced eNOS phosphorylation required estrogen receptor (ER)-mediated phosphatidylinositol 3-kinase (PI3K)/Akt signaling and was reversed by AMP-activated protein kinase (AMPK) and calcium/calmodulin-dependent kinase II (CaMKII) inhibition. Importantly, puerarin inhibited the adhesion of tumor necrosis factor (TNF)-α-stimulated monocytes to endothelial cells and suppressed the TNF-α induced expression of intercellular cell adhesion molecule-1. Puerarin also inhibited the TNF-α-induced nuclear factor-κB activation, which was attenuated by pretreatment with NG-nitro-L-arginine methyl ester, a NOS inhibitor. These results indicate that puerarin stimulates eNOS phosphorylation and NO production via activation of an estrogen receptor-mediated PI3K/Akt- and CaMKII/AMPK-dependent pathway. Puerarin may be useful for the treatment or prevention of endothelial dysfunction associated with diabetes and cardiovascular disease. -- Highlights: ► Puerarin induced the phosphorylation of eNOS and the production of NO. ► Puerarin activated eNOS through ER-dependent PI3-kinase and Ca2+-dependent AMPK. ► Puerarin-induced NO was involved in the inhibition of NF-kB activation. ► Puerarin may help for prevention of vascular dysfunction and diabetes.

  16. Calcium carbonate electronic-insulating layers improve the charge collection efficiency of tin oxide photoelectrodes in dye-sensitized solar cells

    International Nuclear Information System (INIS)

    In dye-sensitized solar cells (DSSCs), a surface passivation layer has been employed on the tin oxide (SnO2) photoanodes to enhance the charge collection efficiency, and thus the power conversion efficiency. Herein, we demonstrate that the electronic-insulating layering of calcium carbonate (CaCO3) can improve the charge collection efficiency in dye-sensitized solar cells designed with photoanodes. In order to evaluate the effectiveness of CaCO3 layering, both layered and pristine SnO2 photoanodes are characterized with regard to their structures, morphologies, and photo-electrochemical measurements. The SnO2-6L CaCO3 photoanode has demonstrated as high as 3.5% power conversion efficiency; 3.5-fold greater than that of the pristine SnO2 photoanode. The enhancement in the power conversion efficiency is corroborated with the number of the dye molecules, the passivation of surface states, a negative shift in the conduction band position, and the reduced electron recombination rate of photoelectrons following the coating of the CaCO3 surface layer

  17. Theoretical analysis of the spin effect on the electronic and magnetic properties of the calcium manganese oxide CaMnO{sub 3}: GGA+U calculation

    Energy Technology Data Exchange (ETDEWEB)

    Hamdad, N., E-mail: hamdad.noura@yahoo.f [Modeling and Simulation in Materials Science Laboratory, University of Sidi Bel-Abbes, Physics Department, Sidi Bel Abbes 22 000 (Algeria); Bouhafs, B. [Modeling and Simulation in Materials Science Laboratory, University of Sidi Bel-Abbes, Physics Department, Sidi Bel Abbes 22 000 (Algeria)

    2010-11-15

    An electron is a magnetic solid that can perturb local moment via exchange interactions between spin and those of the ions. In our paper, we explore the fundamental physics behind the scarcity of ferromagnetic coexistence on the calcium manganese perovskite oxide CaMnO{sub 3}, and examine the structural, electronic and magnetic properties of some known magnetically ordered systems. Various magnetic structures are studied using the first-principles calculation based on density functional theory DFT, using different approximations such as local density approximation (LDA), generalized gradient approximation (GGA), LSDA+U, and GGA+U, which motivated our obtained results. We described in our paper the ground states of different magnetic phases: ferromagnetic (Ferro), A-type anti-ferromagnetic (A-AFM), and G-type anti-ferromagnetic (G-AFM), and the non-spin polarized (NSP) configuration for the ideal cubic perovskite structure. We investigated also a detailed study on the four-layered 4H-hexagonal structure of the compound. We have shown the band structure, density of states and the charge density of all configurations considered in our examination. The magnetic moment and the effect of the U-Hubbard term on our calculation are discussed. Our results are in excellent agreement with available theoretical works and experimental data.

  18. Theoretical analysis of the spin effect on the electronic and magnetic properties of the calcium manganese oxide CaMnO3: GGA+U calculation

    International Nuclear Information System (INIS)

    An electron is a magnetic solid that can perturb local moment via exchange interactions between spin and those of the ions. In our paper, we explore the fundamental physics behind the scarcity of ferromagnetic coexistence on the calcium manganese perovskite oxide CaMnO3, and examine the structural, electronic and magnetic properties of some known magnetically ordered systems. Various magnetic structures are studied using the first-principles calculation based on density functional theory DFT, using different approximations such as local density approximation (LDA), generalized gradient approximation (GGA), LSDA+U, and GGA+U, which motivated our obtained results. We described in our paper the ground states of different magnetic phases: ferromagnetic (Ferro), A-type anti-ferromagnetic (A-AFM), and G-type anti-ferromagnetic (G-AFM), and the non-spin polarized (NSP) configuration for the ideal cubic perovskite structure. We investigated also a detailed study on the four-layered 4H-hexagonal structure of the compound. We have shown the band structure, density of states and the charge density of all configurations considered in our examination. The magnetic moment and the effect of the U-Hubbard term on our calculation are discussed. Our results are in excellent agreement with available theoretical works and experimental data.

  19. 电位滴定法测定石灰中有效氧化钙含量%Potentiotitrimetric Determination of Available Calcium Oxide in Lime

    Institute of Scientific and Technical Information of China (English)

    马兵兵

    2013-01-01

    Content of available calcium oxide in lime was determined by potentiometric titration using HC1 standard solution as titrant. Conditions of titration were optimized and given as follow: ① acidity at endpoint of titration: pH 7. 00; ② maximum rate of titration: 10 mL · min-1 ; ③ minimum rate of titration: 100 μL · min-1; (4) delay time: 5 s. The proposed method was applied to the analysis of lime sample, and the results obtained were checked quite well with those obtained by manual titration. Values of RSD's (n=5) were found in the range of 0. 10%-0. 19%.%采用电位滴定法,用盐酸标准溶液作为滴定剂,测定石灰中有效氧化钙含量.优化的滴定条件为:①滴定终点pH为7.00;②最大馈液速率10 mL·min-1;③最小馈液速率100 μL·min-1;④滞后时间5s;⑤搅拌时间1 min.方法用于石灰样品分析,测定值与手工滴定法测定值相符,相对标准偏差(n=5)在0.10%~0.19%之间.

  20. Capture of gas-phase arsenic oxide by lime: kinetic and mechanistic studies.

    Science.gov (United States)

    Jadhav, R A; Fan, L S

    2001-02-15

    Trace metal emission from coal combustion is a major concern for coal-burning utilities. Toxic compounds such as arsenic species are difficult to control because of their high volatility. Mineral sorbents such as lime and hydrated lime have been shown to be effective in capturing arsenic from the gas phase over a wide temperature range. In this study, the mechanism of interaction between arsenic oxide (As2O3) and lime (CaO) is studied over the range of 300-1000 degrees C. The interaction between these two components is found to depend on the temperature; tricalcium orthoarsenate (Ca3As2O8) is found to be the product of the reaction below 600 degrees C, whereas dicalcium pyroarsenate (Ca2As2O7) is found to be the reaction product in the range of 700-900 degrees C. Maximum capture of arsenic oxide is found to occur in the range of 500-600 degrees C. At 500 degrees C, a high reactivity calcium carbonate is found to capture arsenic oxide by a combination of physical and chemical adsorption. Intrinsic kinetics of the reaction between calcium oxide and arsenic oxide in the medium-temperature range of 300-500 degrees C is studied in a differential bed flow-through reactor. Using the shrinking core model, the order of reaction with respect to arsenic oxide concentration is found to be about 1, and the activation energy is calculated to be 5.1 kcal/mol. The effect of initial surface area of CaO sorbent is studied over a range of 2.7-45 m2/g using the grain model. The effect of other major acidic flue gas species (SO2 and HCl) on arsenic capture is found to be minimal under the conditions of the experiment. PMID:11349294

  1. Nifedipine treatment reduces resting calcium concentration, oxidative and apoptotic gene expression, and improves muscle function in dystrophic mdx mice.

    Directory of Open Access Journals (Sweden)

    Francisco Altamirano

    Full Text Available Duchenne Muscular Dystrophy (DMD is a recessive X-linked genetic disease, caused by mutations in the gene encoding dystrophin. DMD is characterized in humans and in mdx mice by a severe and progressive destruction of muscle fibers, inflammation, oxidative/nitrosative stress, and cell death. In mdx muscle fibers, we have shown that basal ATP release is increased and that extracellular ATP stimulation is pro-apoptotic. In normal fibers, depolarization-induced ATP release is blocked by nifedipine, leading us to study the potential therapeutic effect of nifedipine in mdx muscles and its relation with extracellular ATP signaling. Acute exposure to nifedipine (10 µM decreased [Ca(2+]r, NF-κB activity and iNOS expression in mdx myotubes. In addition, 6-week-old mdx mice were treated with daily intraperitoneal injections of nifedipine, 1 mg/Kg for 1 week. This treatment lowered the [Ca(2+]r measured in vivo in the mdx vastus lateralis. We demonstrated that extracellular ATP levels were higher in adult mdx flexor digitorum brevis (FDB fibers and can be significantly reduced after 1 week of treatment with nifedipine. Interestingly, acute treatment of mdx FDB fibers with apyrase, an enzyme that completely degrades extracellular ATP to AMP, reduced [Ca(2+]r to a similar extent as was seen in FDB fibers after 1-week of nifedipine treatment. Moreover, we demonstrated that nifedipine treatment reduced mRNA levels of pro-oxidative/nitrosative (iNOS and gp91(phox/p47(phox NOX2 subunits and pro-apoptotic (Bax genes in mdx diaphragm muscles and lowered serum creatine kinase (CK levels. In addition, nifedipine treatment increased muscle strength assessed by the inverted grip-hanging test and exercise tolerance measured with forced swimming test in mdx mice. We hypothesize that nifedipine reduces basal ATP release, thereby decreasing purinergic receptor activation, which in turn reduces [Ca(2+]r in mdx skeletal muscle cells. The results in this work open new

  2. Evaluation of palm oil mill fly ash supported calcium oxide as a heterogeneous base catalyst in biodiesel synthesis from crude palm oil

    International Nuclear Information System (INIS)

    Highlights: • Calcination temperature is an important influencing factor in catalytic activity. • The optimum calcination conditions were determined to be 850 °C for 2 h. • Maximum yield of 79.8% and FAME conversion of 97.1% was achieved. • Kinetic data fitted the pseudo-first order model and the Ea was 42.56 kJ mol−1. • The novel catalyst can be reused for 3 cycles with a final biodiesel yield of 60%. - Abstract: A palm oil mill fly ash supported calcium oxide (CaO) catalyst was developed to be used as a heterogeneous base catalyst in biodiesel synthesis from crude palm oil (CPO). The catalyst preparation procedure was optimised in terms of final calcination temperature and duration. The optimum catalyst preparation conditions were determined as final calcination at 850 °C for 2 h with 45 wt.% loading of calcined calcium carbonate (CaCO3). A maximum biodiesel yield of 75.73% was achieved for this catalyst under fixed transesterification conditions. Characterisation tests showed that the catalyst had higher surface area and basic sites which favoured transesterification. The effects of catalyst loading, methanol to oil molar ratio, reaction temperature and reaction time on biodiesel yield and fatty acid methyl ester (FAME) conversion were also investigated. It was determined that transesterification conditions of 6 wt.% catalyst loading, 12:1 methanol to oil molar ratio, 45 °C reaction temperature, 3 h reaction time and 700 rpm stirring speed resulted in biodiesel yield and FAME conversion of 79.76% and 97.09%, respectively. Experimental kinetic data obtained from the heterogeneous transesterification reactions fitted the pseudo-first order kinetic model. The activation energy (Ea) of the reaction was calculated to be 42.56 kJ mol−1. Key physicochemical properties of the produced biodiesel were measured and found to be within the limits set by EN 14214. The developed catalyst could feasibly be used up to three consecutive cycles after regeneration

  3. Reaction Mechanism of Calcium Hydroxide with Gaseous Hydrogen Chloride Mécanisme de réaction de l'hydroxyde de calcium avec de l'acide chlorhydrique gazeux

    Directory of Open Access Journals (Sweden)

    Allal K. M.

    2006-12-01

    Full Text Available The reduction of acid gas content in combustion or incineration flue gases can be carried out by reaction with dry, fine alkaline sorbents such as calcium oxide or calcium hydroxide. In the present work, in addition to the thermodynamic study of the different reactions involved in the dechlorination process, an experimental study to identify the reaction products by means of X-ray diffraction, electron microscopy and thermogravimetry has been carried out. It has been shown that the reaction of hydrochloric acid with hydrated lime leads to the formation of not only calcium chloride but calcium hydroxichloride. La diminution de la teneur en gaz acides dans les effluents provenant des unités de combustion ou d'incinération peut être accomplie en faisant réagir ces gaz polluants avec des absorbants alcalins tels que l'oxyde ou l'hydroxyde de calcium. Dans cet article, à l'étude thermodynamique des différentes réactions mises en jeu durant le processus de déchloruration, s'ajoute une étude expérimentale menant à l'identification des produits finaux en utilisant la diffraction X, la microscopie électronique ainsi que la thermogravimétrie. A l'issue de cette étude, il a été montré que la réaction de Ca(OH2 avec HCl entraîne la formation non seulement de CaCI2 mais aussi CaCIOH.

  4. Hydrogen sulfide removal from hot coal gas by various mesoporous silica supported Mn2O3 sorbents

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Mn2O3/KIT-1 presented the best desulfurization performance at 600–850 °C. • High sulfur capacity of Mn2O3/KIT-1 correlated closely with 3-D channel of KIT-1. • Desulfurization character depended strongly on framework structure of sorbents. • High steam content suppressed greatly the occurrence of sulfidation reaction. - Abstract: A series of 50 wt% Mn2O3 sorbents was prepared using various mesoporous silica, MCM-41, HMS, and KIT-1 as support. The influence of textural parameters of mesoporous silica, especially type of channel on the desulfurization performance of Mn2O3 sorbents was investigated at 600–850 °C using hot coal gas containing 0.33 vol.% H2S. The fresh and used sorbents were characterized by means of N2-adsorption, x-ray diffraction (XRD), high resolution transmission microscopy (HRTEM) and H2 temperature- programmed reduction (H2-TPR) techniques. The results confirmed that the manganese oxide was dispersed highly in regular pore channel of the mesoporous supports due to high surface area. Compared with the Mn2O3/diatomite, all mesoporous silica supported Mn2O3 sorbents exhibited high breakthrough sulfur capacity and a sharp deactivation rate after the breakthrough point. Compared to Mn2O3/MCM-41 and Mn2O3/HMS sorbent, the Mn2O3/KIT-1 showed better desulfurization performance because of the 3D wormhole-like channel. The high sulfur capacity of the Mn2O3/KIT-1 sorbent was maintained during the eight consecutive desulfurization-regeneration cycles. The Mn2O3/KIT-1 still presented high desulfurization activity when hot coal gas contained low steam (<5%)

  5. Calcium in plant cells

    Directory of Open Access Journals (Sweden)

    V. V. Schwartau

    2014-04-01

    connect ion conformationally rearranged, thus passing the signal through the chain of intermediaries. The most important function of calcium is its participation in many cell signaling pathways. Channels, pumps, gene expression, synthesis of alkaloids, protective molecules, NO etc. respond to changes in [Ca2+]cyt, while transductors are represented by a number of proteins. The universality of calcium is evident in the study in connection with other signaling systems, such as NO, which is involved in the immune response and is able to control the feedback activity of protein activators channels, producing nitric oxide. Simulation of calcium responses can determine the impact of key level and their regulation, and also depends on the type of stimulus and the effector protein that specifically causes certain changes. Using spatiotemporal modeling, scientists showed that the key components for the formation of Ca2+ bursts are the internal and external surfaces of the nucleus membrane. The research was aimed at understanding of the mechanisms of influence of Ca2+-binding components on Ca2+ oscillations. The simulation suggests the existence of a calcium depot EPR with conjugated lumen of the nucleus which releases its contents to nucleoplasm. With these assumptions, the mathematical model was created and confirmed experimentally. It describes the oscillation of nuclear calcium in root hairs of Medicago truncatula at symbiotic relationship of plants and fungi (rhizobia. Calcium oscillations are present in symbiotic relationships of the cortical layer of plant root cells. Before penetration of bacteria into the cells, slow oscillations of Ca2+ are observed, but with their penetration into the cells the oscillation frequency increases. These processes take place by changing buffer characteristics of the cytoplasm caused by signals from microbes, such as Nod-factor available after penetration of bacteria through the cell wall. Thus, the basic known molecular mechanisms for

  6. Development and testing of regenerable hot-coal-gas desulfurization sorbents

    Energy Technology Data Exchange (ETDEWEB)

    Grindley, T.; Steinfeld, G.

    1981-10-01

    Investigations over several years at the Morgantown Energy Technology Center have been concerned with the development of a regenerable metal oxide desulfurization sorbent which would function on hot coal-derived fuel gas. In the latest phase of testing, a combination of zinc oxide with iron oxide as zinc ferrite has produced a sorbent which has demonstrated regenerability and capability of removing sulfur from simulated hot coal gas to a level of 1 to 10 ppM by volume. The principal finding at this stage of the project is that the compound zinc ferrite and also iron oxide containing some zinc ferrite have hydrogen sulfide absorption performances very similar to those of zinc oxide. Extruded sorbents made from these compounds have been demonstrated to perform with varying ability in the temperature range 800/sup 0/F (427/sup 0/C) to 1400/sup 0/F (760/sup 0/C) at a space velocity of 2000 hourly and a hydrogen sulfide concentration of 2.7 percent. They have also been shown to be regenerable with a 50/50 percent v/v steam-air mixture at 1000/sup 0/F (538/sup 0/C) and 600 hourly space velocity with no loss of absorptive power. Both zinc ferrite and zinc oxide appear to perform optimally in the middle of the temperature range, where absorption capacity is greatest. Surprisingly, the experimental results indicate no trend to a lower degree of hydrogen sulfide removal with rise in temperature. Zinc ferrite appears to be superior to zinc oxide in terms of its absorption capacity and resistance to sintering at higher temperatures.

  7. Calcium pyrophosphate arthritis

    Science.gov (United States)

    Calcium pyrophosphate dihydrate deposition disease; CPPD disease; Acute CPPD arthritis; Pseudogout ... Calcium pyrophosphate arthritis is caused by the collection of salt called calcium pyrophosphate dihydrate (CPPD). The buildup ...

  8. GABAB Receptors Expressed in Human Aortic Endothelial Cells Mediate Intracellular Calcium Concentration Regulation and Endothelial Nitric Oxide Synthase Translocation

    Directory of Open Access Journals (Sweden)

    Xu-Ping Wang

    2014-01-01

    Full Text Available GABAB receptors regulate the intracellular Ca2+ concentration ([Ca2+]i in a number of cells (e.g., retina, airway epithelium and smooth muscle, but whether they are expressed in vascular endothelial cells and similarly regulate the [Ca2+]i is not known. The purpose of this study was to investigate the expression of GABAB receptors, a subclass of receptors to the inhibitory neurotransmitter γ-aminobutyric acid (GABA, in cultured human aortic endothelial cells (HAECs, and to explore if altering receptor activation modified [Ca2+]i and endothelial nitric oxide synthase (eNOS translocation. Real-time PCR, western blots and immunofluorescence were used to determine the expression of GABAB1 and GABAB2 in cultured HAECs. The effects of GABAB receptors on [Ca2+]i in cultured HAECs were demonstrated using fluo-3. The influence of GABAB receptors on eNOS translocation was assessed by immunocytochemistry. Both GABAB1 and GABAB2 mRNA and protein were expressed in cultured HAECs, and the GABAB1 and GABAB2 proteins were colocated in the cell membrane and cytoplasm. One hundred μM baclofen caused a transient increase of [Ca2+]i and eNOS translocation in cultured HAECs, and the effects were attenuated by pretreatment with the selective GABAB receptor antagonists CGP46381 and CGP55845. GABAB receptors are expressed in HAECs and regulate the [Ca2+]i and eNOS translocation. Cultures of HAECs may be a useful in vitro model for the study of GABAB receptors and vascular biology.

  9. Economic analysis of engineered sorbent barrier technology

    International Nuclear Information System (INIS)

    This paper evaluates the incremental cost of placing an engineered sorbent barrier beneath a shallow land burial (SLB) site in a humid climate. The cost estimates are also applicable to alternative uses of sorbent barrier technology such as redundant barriers around below-grade vaults. The preliminary costs presented represent only rough order-of-magnitude estimates. Further information obtained from field studies and refined performance models would allow a more precise cost estimate to be prepared. Flow-through column tests have shown that clinoptilolite is much more effective in sorbing strontium than indicated previously. The effectiveness of the barrier for cobalt was not as good as that measured previously. The costs in this paper are based on these updated data. 8 refs., 1 fig., 4 tabs

  10. New polymer bounces into sorbent market

    International Nuclear Information System (INIS)

    Spectacular spills like the Exxon Valdez capture headlines and dominate conversation, but most releases involve quantities too small to attract media attention. For these spills, companies often rely on sorbents to collect the oil and dispose it. These devices come in a variety of shapes, sizes and absorbent materials, including a new generation of products that offers solid results-literally. This paper reports on the Solidifier which absorbs oil, as well as chlorinated solvents, hydrocarbons and PCBs, and, as the name implies, solidifies into a rubber-like material. A polymer used extensively in the rubber industry is the key to the sorbent's success. Oil and other contaminants, act like catalysts. They dissolve into the polymer, causing its molecules to bond together and form a rubber-like mass. No. 2 diesel fuel oil can be bounced on the floor after it solidifies

  11. Nanomaterials as Sorbents for Water Treatment

    Czech Academy of Sciences Publication Activity Database

    Matějková, Martina; Soukup, Karel; Grabowski, J.; Šolcová, Olga

    Maribor : Inštitut za okoljevarstvo in senzorje d.o.o, 2013 - (Lobnik, A.; Gutmaher, A.), P2 ISBN 978-961-92863-2-6. [International Scientific Conference on Nanomaterials and Applications NANOAPP /1./. Portorož (SI), 22.09.2013-26.09.2013] Grant ostatní: RFCS(XE) RFCR-CT-2011-00002 Institutional support: RVO:67985858 Keywords : sorbents * water treatment * phenols Subject RIV: CI - Industrial Chemistry, Chemical Engineering

  12. Evaluation of different cleanup sorbents for multiresidue pesticide analysis in fatty vegetable matrices by liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    López-Blanco, Rafael; Nortes-Méndez, Rocío; Robles-Molina, José; Moreno-González, David; Gilbert-López, Bienvenida; García-Reyes, Juan F; Molina-Díaz, Antonio

    2016-07-22

    In this article we have evaluated the performance of different sorbents for the cleanup step in multiresidue pesticide analysis in fatty vegetable matrices using QuEChERS methodology. The three different matrices tested (olive oil, olives and avocado) were partitioned using acetonitrile prior to cleanup step. Afterwards, the supernatant was purified using different sorbents: C18+PSA (primary secondary amine), Z-Sep(+) (zirconium oxide and C18 dual bonded to silica), Z-Sep (zirconium oxide bonded to silica) and a novel sorbent Enhanced Matrix Removal-Lipid (EMR) whose composition has not been disclosed. The different cleanup strategies were compared for a group of 67 representative pesticides in terms of recovery rates, matrix effects, extract cleanliness and precision using ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS). The best extraction efficiencies in olive oil matrix were obtained using EMR, while the results for olives and avocado were pretty similar amongst the different sorbents with an overall lower performance in terms of matrix effects and recovery rates compared to olive oil data, particularly in olives due to the higher complexity and concentration of coextracted species. On the other hand, the average reproducibility was clearly better when EMR sorbent was employed in all selected matrices for most pesticides (RSDoil respectively). The best results in terms of matrix effects were also obtained with EMR; with signal suppression lower than 20% for 79%, 16% and 51% of pesticides tested in olive oil, olives and avocado respectively. Using EMR as cleanup sorbent, limits of quantitation using UHPLC-MS/MS, ranged from 0.10 to 90μgkg(-1), allowing their determination at the low concentration levels demanded by current olive oil regulations in most cases. PMID:27328883

  13. Spectroscopic Investigation of the Mechanisms Responsible for the Superior Stability of Hybrid Class 1/Class 2 CO2 Sorbents: A New Class 4 Category.

    Science.gov (United States)

    Wilfong, Walter Christopher; Kail, Brian W; Jones, Christopher W; Pacheco, Carlos; Gray, McMahan L

    2016-05-25

    Hybrid Class 1/Class 2 supported amine CO2 sorbents demonstrate superior performance under practical steam conditions, yet their amine immobilization and stabilization mechanisms are unclear. Uncovering the interactions responsible for the sorbents' robust features is critical for further improvements and can facilitate practical applications. We employ solid state (29)Si CP-MAS and 2-D FSLG (1)H-(13)C CP HETCOR NMR spectroscopies to probe the overall molecular interactions of aminosilane/silica, polyamine [poly(ethylenimine), PEI]/silica, and hybrid aminosilane/PEI/silica sorbents. A unique, sequential impregnation sorbent preparation method is executed in a diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) setup to decouple amine binding mechanisms at the amine-silica interface from those within bulk amine layers. These mechanisms are correlated with each sorbents' resistance to accelerated liquid H2O and TGA steam treatments (H2O stability) and to oxidative degradation (thermal stability). High percentages of CO2 capture retained (PCR) and organic content retained (OCR) values after H2O testing of N-(3-(trimethoxysilyl)propyl)ethylenediamine (TMPED)/PEI and (3-aminopropyl)trimethoxysilane (APTMS)/PEI hybrid sorbents are associated with a synergistic stabilizing effect of the amine species observed during oxidative degradation (thermal gravimetric analysis-differential scanning calorimetry, TGA-DSC). Solid state NMR spectroscopy reveals that the synergistic effect of the TMPED/PEI mixture is manifested by the formation of hydrogen-bonded PEI-NH2···NH2-TMPED and PEI-NH2···HO-Si/O-Si-O (TMPED, T(2)) linkages within the sorbent. DRIFTS further determines that PEI enhances the grafting of TMPED to silica and that PEI is dispersed among a stable network of polymerized TMPED in the bulk, utilizing H-bonded linkages. These findings provide the scientific basis for establishing a Class 4 category for aminosilane/polyamine/silica hybrid sorbents

  14. Calcium and bones

    Science.gov (United States)

    Bone strength and calcium ... calcium (as well as phosphorus) to make healthy bones. Bones are the main storage site of calcium in ... your body does not absorb enough calcium, your bones can get weak or will not grow properly. ...

  15. Get Enough Calcium

    Science.gov (United States)

    ... Calcium Print This Topic En español Get Enough Calcium Browse Sections The Basics Overview Foods and Vitamins ... 2 of 4 sections Take Action! Take Action: Calcium Sources Protect your bones – get plenty of calcium ...

  16. Calcium carbonate overdose

    Science.gov (United States)

    Tums overdose; Calcium overdose ... Calcium carbonate can be dangerous in large amounts. ... Some products that contain calcium carbonate are certain: ... and mineral supplements Other products may also contain calcium ...

  17. The Effects of Vitamin D-K-Calcium Co-Supplementation on Endocrine, Inflammation, and Oxidative Stress Biomarkers in Vitamin D-Deficient Women with Polycystic Ovary Syndrome: A Randomized, Double-Blind, Placebo-Controlled Trial.

    Science.gov (United States)

    Razavi, M; Jamilian, M; Karamali, M; Bahmani, F; Aghadavod, E; Asemi, Z

    2016-07-01

    The current study was conducted to assess the effects of vitamin D-K-calcium co-supplementation on endocrine, inflammation, and oxidative stress biomarkers in vitamin D-deficient women with polycystic ovary syndrome (PCOS). This randomized double-blind, placebo-controlled trial was performed on 60 vitamin D-deficient women diagnosed with PCOS aged 18-40 years old. Participants were randomly allocated into 2 groups to intake either 200 IU vitamin D, 90 μg vitamin K plus, 500 mg calcium supplements (n=30), or placebo (n=30) twice a day for 8 weeks. Endocrine, inflammation, and oxidative stress biomarkers were quantified at the beginning and the end of the study. After 8 weeks of intervention, compared with the placebo, vitamin D-K-calcium co-supplementation resulted in a significant reduction in serum-free testosterone (- 2.1±1.6 vs.+0.1±1.0 pg/ml, pPCOS had beneficial effects on serum DHEAS, free testosterone, plasma TAC, and MDA levels. PMID:27050252

  18. Ferromagnetic Sorbents for Collection an Utilization of Oil Products

    OpenAIRE

    Mironovs, V.; Lapkovskis, V.; Treijs, J.; Teirumnieks, E

    2011-01-01

    The paper deals with powder-like ferromagnetic sorbents for collection of the oil products spilled in water. Research is performed on properties, morphology of particles and comparison of different types of the ferromagnetic sorbents obtained on the basis of ferrous powders and technological waste, such as a rolled scale and pulverulent waste from filters. By means of the specially created electromagnetic device, efficiency of some types of ferromagnetic sorbents is tested for remova...

  19. Arsenic Adsorption Onto Iron Oxides Minerals

    Science.gov (United States)

    Aredes, S.; Klein, B.; Pawlik, M.

    2004-12-01

    The predominant form of arsenic in water is as an inorganic ion. Under different redox conditions arsenic in water is stable in the +5 and +3 oxidation states. Arsenic oxidation state governs its toxicity, chemical form and solubility in natural and disturbed environments. As (III) is found in anoxic environments such as ground water , it is toxic and the common species is the neutral form, H3AsO3. As (V) is found in aerobic conditions such as surface water, it is less toxic and the common species in water are: H2AsO4 - and HAsO4 {- 2}. The water pH determines the predominant arsenate or arsenite species, however, both forms of arsenic can be detected in natural water systems. Iron oxides minerals often form in natural waters and sediments at oxic-anoxic boundaries. Over time they undergo transformation to crystalline forms, such as goethite or hematite. Both As(V) and As(III) sorbs strongly to iron oxides, however the sorption behavior of arsenic is dependent on its oxidation state and the mineralogy of the iron oxides. Competition between arsenic and others ions, such fluoride, sulphate and phosphate also play a role. On the other hand, calcium may increase arsenic adsorption onto iron oxides. Electrokinetic studies and adsorption experiments were carried out in order to determine which conditions favour arsenic adsorption. Hematite, goethite and magnetite as iron based sorbents were used. Test were also conducted with a laterite soil rich in iron minerals. The focus of this study is to evaluate physical and chemical conditions which favour arsenic adsorption onto iron oxides minerals, the results contribute to an understanding of arsenic behaviour in natural and disturbed environments. Furthermore, results could contribute in developing an appropriate remediation technology for arsenic removal in water using iron oxides minerals.

  20. Regularities in aluminium and indium chemisorption on chelating polymeric sorbents

    International Nuclear Information System (INIS)

    Complexation properties of synthesized polymer chelate sorbents: substituted of polystyrene-azo-pyrocatechol are investigated and correlations between pK'OH of functional groups of sorbents as well as pH50 values of chelation and constants of stability (lgKstab) are established for studying regularities of effect of structure and acid-base properties of functional groups of sorbents on the parameters of Al3+ and In3+ chemical sorption. Established correlations make it possible to predict the physicochemical parameters of sorbents and sorption of metal ions with the aim of separation and concentration of aluminium and indium micro account from the objects of different origin

  1. Simple test guidelines for screening oilspill sorbents for toxicity

    International Nuclear Information System (INIS)

    Environment Canada's Emergencies Science Division has established a program to develop a standard test method suitable for evaluating the toxicity of common sorbent materials. Sorbents are used to absorb or adsorb spilled oil and other hazardous materials. They vary widely in composition and packaging. They are often treated with oleophilic and hydrophobic compounds to improve performance and have been used in large quantities during oil spills. Until now, their potential toxicity has never been considered. Three tests have been evaluated to determine how appropriate they are in screening the toxicity of sorbents. Seven toxicity test recommendations for sorbents were presented. 7 refs., 3 tabs., 2 figs

  2. 湿法烟气脱硫环境下亚硫酸钙的非催化氧化%NON-CATALYTIC OXIDATION KINETICS OF CALCIUM SULFITE IN WET LIMESTONE-GYPSUM FGD PROCESS

    Institute of Scientific and Technical Information of China (English)

    杜谦; 吴少华; 朱群益; 秦裕琨

    2003-01-01

    A study on non-catalytic oxidation kinetics of calcium sulfite is presented under typical conditions of wet flue gas desulfurization (FGD)in this paper. A laboratory-scale mechanically stirred tank reactor is used with continuous feed of both gas and liquid phase. The results show that increasing CaSO3 load from a lower value, the reaction rate increases and is limited by solid sulfite dissolution. The oxidation rate limitation is observed at loads exceeding certain concentration. The rate limitation is possibly caused by solid sulfite solubility or oxygen gas-liquid diffusion. The experimental conclusions are useful for design and operation of the holding tank in forced-oxidation wet FGD.

  3. Modeling packed bed sorbent systems with the Pore Surface Diffusion Model: Evidence of facilitated surface diffusion of arsenate in nano-metal (hydr)oxide hybrid ion exchange media.

    Science.gov (United States)

    Dale, Sachie; Markovski, Jasmina; Hristovski, Kiril D

    2016-09-01

    This study explores the possibility of employing the Pore Surface Diffusion Model (PSDM) to predict the arsenic breakthrough curve of a packed bed system operated under continuous flow conditions with realistic groundwater, and consequently minimize the need to conduct pilot scale tests. To provide the nano-metal (hydr)oxide hybrid ion exchange media's performance in realistic water matrices without engaging in taxing pilot scale testing, the multi-point equilibrium batch sorption tests under pseudo-equilibrium conditions were performed; arsenate breakthrough curve of short bed column (SBC) was predicted by the PSDM in the continuous flow experiments; SBC tests were conducted under the same conditions to validate the model. The overlapping Freundlich isotherms suggested that the water matrix and competing ions did not have any denoting effect on sorption capacity of the media when the matrix was changed from arsenic-only model water to real groundwater. As expected, the PSDM provided a relatively good prediction of the breakthrough profile for arsenic-only model water limited by intraparticle mass transports. In contrast, the groundwater breakthrough curve demonstrated significantly faster intraparticle mass transport suggesting to a surface diffusion process, which occurs in parallel to the pore diffusion. A simple selection of DS=1/2 DP appears to be sufficient when describing the facilitated surface diffusion of arsenate inside metal (hydr)oxide nano-enabled hybrid ion-exchange media in presence of sulfate, however, quantification of the factors determining the surface diffusion coefficient's magnitude under different treatment scenarios remained unexplored. PMID:26672387

  4. Calcium paradox and calcium entry blockers

    NARCIS (Netherlands)

    Ruigrok, T.J.C.; Slade, A.M.; Nayler, W.G.; Meijler, F.L.

    1984-01-01

    Reperfusion of isolated hearts with calcium-containing solution after a short period of calcium-free perfusion results in irreversible cell damage (calcium paradox). This phenomenon is characterized by an excessive influx of calcium into the cells, the rapid onset of myocardial contracture, exhausti

  5. Improved Regenerative Sorbent-Compressor Refrigerator

    Science.gov (United States)

    Jones, Jack A.

    1992-01-01

    Conceptual regenerative sorbent-compressor refrigerator attains regeneration efficiency and, therefore, overall power efficiency and performance greater than conventional refrigerators. Includes two fluid loops. In one, CH2FCF3 (R134a) ciculates by physical adsorption and desorption in four activated-charcoal sorption compressors. In other, liquid or gas coolant circulated by pump. Wave of regenerative heating and cooling propagates cyclically like peristatic wave among sorption compressors and associated heat exchangers. Powered by electricity, oil, gas, solar heat, or waste heat. Used as air conditioners, refrigerators, and heat pumps in industrial, home, and automotive applications.

  6. Study of silica sorbents by SANS

    International Nuclear Information System (INIS)

    Silica gels under study are materials intended for use as the packing sorbents in liquid chromatography (LC), namely in gel permeation chromatography (GPC). The quality of silica for LC should meet strict physical and chemical parameters. Especially in GPC is very important to know pore size and pore shape because they control the whole process of chromatographic separation. Pore size and thickness of pore wall can be measured by various methods. SANS technique is a nondestructive method providing an average information about a large number of scattering object in our case about objects (pore or wall) in silica and their shape. (author)

  7. SORBENTS FOR EXTRACTION OF SPILLED FUEL-LUBRICATE MATERIALS

    Directory of Open Access Journals (Sweden)

    Natalya V. Mashinskaya

    2009-04-01

    Full Text Available  Properties of absorbents of biological structure have been researched in the work. Its main advantages in comparison with chemical and polymeric sorbents have been shown. The offered Canadian peat-moss can be used in Ukraine as sorbent for oil products spill liquidation.

  8. Oil spill sorbents: Testing protocol and certification listing program

    International Nuclear Information System (INIS)

    A universally accepted standard method for testing oil spill sorbents is not currently employed by most sorbent manufacturers. Environment Canada is leading the development of an official Canadian standard for the testing and certification of sorbents using the Canadian General Standards Board as the certification body. A committee was formed through the Board consisting of representation from interested parties, producers, and end-users throughout North America. This led to the development of a new test procedure based on previous Environment Canada work and also incorporating methods from the American Society for Testing and Materials. The Board's certification and listing program currently consists of two documents, one being a standard for sorbent materials and the other specifically defining testing procedures for sorbents used on crude oil and similar spills. The program is structured to allow introduction of additional testing protocols. Standard CSA/CBSB-183.2 covers lab-conducted performance tests for all forms of sorbent materials. Specific performance characteristics identified as highly desirable in these materials include buoyancy, low water pickup, high oil pickup, reusability, and low rate of release. Established test methods include static and dynamic degradation tests and pre-tests, and tests to evaluate sorbent capacity, reuse, and retention. A draft method for testing sorbents is appended. 2 refs

  9. Trace contaminant adsorption and sorbent regeneration in closed ecological systems

    Science.gov (United States)

    Arnold, C. R.; Kersels, G. J.; Merrill, R. P.; Robell, A. J.; Wheeler, A.

    1972-01-01

    Correlation was obtained for determining sorptive capacity of carbon for pure and mixed contaminants under dry and humid conditions at various temperatures. Vacuum desorption rates were investigated for single particles and for sorbent beds. For sorbent beds, rate-determining step is Knudsen diffusion through interparticle voids.

  10. Comprehensive sulfation model verified for T-T sorbent clusters during flue gas desulfurization at moderate temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Yuran Li; Haiying Qi; Changfu You; Lizhai Yang [Tsinghua University, Beijing (China). Key Laboratory for Thermal Science and Power Engineering of Ministry of Education

    2010-08-15

    An empirical sulfation model for T-T sorbent clusters was developed based on amassed experimental results under moderate temperatures (300-800{sup o}C). In the model, the reaction rate is a function of clusters mass, SO{sub 2} concentration, CO{sub 2} concentration, calcium conversion and temperature. The smaller pore volume partly results in a lower reaction rate at lower temperatures. The exponent on SO{sub 2} concentration is 0.88 in the rapid reaction stage and then decreases gradually as reaction progresses. The exponent on the fraction of the unreacted calcium is 1/3 in the first stage and then increases significantly in the second stage. The CO{sub 2} concentration has a negative influence on SO{sub 2} removal, especially for the temperature range of 400-650{sup o}C, which should be avoided to achieve a high effective calcium conversion. The sulfation model has been verified for the T-T sorbent clusters and has also been applied to CaO particles. Over extensive reaction conditions, the predictions agree well with experimental data. 17 refs., 10 figs., 2 tabs.

  11. CARBON DIOXIDE CAPTURE FROM FLUE GAS USING DRY REGENERABLE SORBENTS

    Energy Technology Data Exchange (ETDEWEB)

    David A. Green; Thomas Nelson; Brian S. Turk; Paul Box; Weijiong Li; Raghubir P. Gupta

    2005-07-01

    This report describes research conducted between April 1, 2005 and June 30, 2005 on the use of dry regenerable sorbents for removal of carbon dioxide from flue gas from coal combustion and synthesis gas from coal gasification. Supported sodium carbonate sorbents removed up to 76% of the carbon dioxide from simulated flue gas in a downflow cocurrent flow reactor system, with an approximate 15 second gas-solid contact time. This reaction proceeds at temperatures as low as 25 C. Lithium silicate sorbents remove carbon dioxide from high temperature simulated flue gas and simulated synthesis gas. Both sorbent types can be thermally regenerated and reused. The lithium silicate sorbent was tested in a thermogravimetric analyzer and in a 1-in quartz reactor at atmospheric pressure; tests were also conducted at elevated pressure in a 2-in diameter high temperature high pressure reactor system. The lithium sorbent reacts rapidly with carbon dioxide in flue gas at 350-500 C to absorb about 10% of the sorbent weight, then continues to react at a lower rate. The sorbent can be essentially completely regenerated at temperatures above 600 C and reused. In atmospheric pressure tests with synthesis gas of 10% initial carbon dioxide content, the sorbent removed over 90% of the carbon dioxide. An economic analysis of a downflow absorption process for removal of carbon dioxide from flue gas with a supported sodium carbonate sorbent suggests that a 90% efficient carbon dioxide capture system installed at a 500 MW{sub e} generating plant would have an incremental capital cost of $35 million ($91/kWe, assuming 20 percent for contingencies) and an operating cost of $0.0046/kWh. Assuming capital costs of $1,000/kW for a 500 MWe plant the capital cost of the down flow absorption process represents a less than 10% increase, thus meeting DOE goals as set forth in its Carbon Sequestration Technology Roadmap and Program Plan.

  12. Advanced in-duct sorbent injection for SO{sub 2} control. Final technical report

    Energy Technology Data Exchange (ETDEWEB)

    Stouffer, M.R.; Withium, J.A.; Rosenhoover, W.A.; Maskew, J.T.

    1994-12-01

    The objective of this research project was to develop a second generation duct sorbent injection technology as a cost-effective compliance option for the 1990 Clean Air Act Amendments. Research and development work was focused on the Advanced Coolside process, which showed the potential for exceeding the original performance targets of 90% SO{sub 2} removal and 60% sorbent utilization. Process development was conducted in a 1000 acfm pilot plant. The pilot plant testing showed that the Advanced Coolside process can achieve 90% SO{sub 2} removal at sorbent utilizations up to 75%. The testing also showed that the process has the potential to achieve very high removal efficiency (90 to >99%). By conducting conceptual process design and economic evaluations periodically during the project, development work was focused on process design improvements which substantially lowered process capital and operating costs, A final process economic study projects capital costs less than one half of those for limestone forced oxidation wet FGD. Projected total SO{sub 2} control cost is about 25% lower than wet FGD for a 260 MWe plant burning a 2.5% sulfur coal. A waste management study showed the acceptability of landfill disposal; it also identified a potential avenue for by-product utilization which should be further investigated. Based on the pilot plant performance and on the above economic projections, future work to scale up the Advanced Coolside process is recommended.

  13. Formation of ettringite, Ca6Al2(SO4)3(OH)12·26H2O, AFt, and monosulfate, Ca4Al2O6(SO4)·14H2O, AFm-14, in hydrothermal hydration of Portland cement and of calcium aluminum oxide--calcium sulfate dihydrate mixtures studied by in situ synchrotron X-ray powder diffraction

    International Nuclear Information System (INIS)

    In the hydration of calcium aluminum oxide-gypsum mixtures, i.e., Ca3Al2O6, Ca12Al14O33 and CaSO4·2H2O, the reaction products can be ettringite, Ca6Al2(SO4)3(OH)12·26H2O, monosulfate, Ca4Al2O6(SO4)·14H2O, or the calcium aluminum oxide hydrate, Ca4Al2O7·19H2O. Ettringite is formed if sufficient CaSO4·2H2O is present in the mixture. Ettringite is converted to monosulfate when all CaSO4·2H2O is consumed in the synthesis of ettringite. The reactions were investigated in the temperature range 25-170 degree sign C using in situ synchrotron X-ray powder diffraction. This technique allows the study of very fast chemical reactions that are observed here under hydrothermal conditions. A new experimental approach was developed to perform in situ mixing of the reactants during X-ray data collection

  14. Efficient Theoretical Screening of Solid Sorbents for CO2 Capture Applications*

    Energy Technology Data Exchange (ETDEWEB)

    Duan, Yuhua; Luebke, David; Pennline, Henry

    2012-03-31

    By combining thermodynamic database mining with first principles density functional theory and phonon lattice dynamics calculations, a theoretical screening methodology to identify the most promising CO2 sorbent candidates from the vast array of possible solid materials has been proposed and validated. The ab initio thermodynamic technique has the advantage of allowing identification of thermodynamic properties of CO2 capture reactions without any experimental input beyond crystallographic structural information of the solid phases involved. For a given solid, the first step is to attempt to extract thermodynamic properties from thermodynamic databases and the available literatures. If the thermodynamic properties of the compound of interest are unknown, an ab initio thermodynamic approach is used to calculate them. These properties expressed conveniently as chemical potentials and heat of reactions, which obtained either from databases or from calculations, are further used for computing the thermodynamic reaction equilibrium properties of the CO2 absorption/desorption cycles. Only those solid materials for which lower capture energy costs are predicted at the desired process conditions are selected as CO2 sorbent candidates and are further considered for experimental validations. Solid sorbents containing alkali and alkaline earth metals have been reported in several previous studies to be good candidates for CO2 sorbent applications due to their high CO2 absorption capacity at moderate working temperatures. In addition to introducing our computational screening procedure, in this presentation we will summarize our results for solid systems composed by alkali and alkaline earth metal oxides, hydroxides, and carbon- ates/bicarbonates to validate our methodology. Additionally, applications of our computational method to mixed solid systems of Li2O with SiO2/ZrO2 with different mixing ratios, our preliminary results showed that increasing the Li2O/SiO2 ratio in

  15. Calcium and bones (image)

    Science.gov (United States)

    Calcium is one of the most important minerals for the growth, maintenance, and reproduction of the human ... body, are continually being re-formed and incorporate calcium into their structure. Calcium is essential for the ...

  16. Coronary Calcium Scan

    Science.gov (United States)

    ... the NHLBI on Twitter. What Is a Coronary Calcium Scan? A coronary calcium scan is a test ... you have calcifications in your coronary arteries. Coronary Calcium Scan Figure A shows the position of the ...

  17. Calcium hydroxide poisoning

    Science.gov (United States)

    Hydrate - calcium; Lime milk; Slaked lime ... Calcium hydroxide ... These products contain calcium hydroxide: Cement Limewater Many industrial solvents and cleaners (hundreds to thousands of construction products, flooring strippers, brick cleaners, cement ...

  18. Calcium source (image)

    Science.gov (United States)

    Getting enough calcium to keep bones from thinning throughout a person's life may be made more difficult if that person has ... as a tendency toward kidney stones, for avoiding calcium-rich food sources. Calcium deficiency also effects the ...

  19. Calcium in diet

    Science.gov (United States)

    Diet - calcium ... Calcium is one of the most important minerals for the human body. It helps form and maintain healthy teeth and bones. A proper level of calcium in the body over a lifetime can help ...

  20. Calcium Pyrophosphate Deposition (CPPD)

    Science.gov (United States)

    ... Patient / Caregiver Diseases & Conditions Calcium Pyrophosphate Deposition (CPPD) Calcium Pyrophosphate Deposition (CPPD) Fast Facts The risk of ... young people, too. Proper diagnosis depends on detecting calcium pyrophosphate crystals in the fluid of an affected ...

  1. Synthesis of a nanosilica supported CO2 sorbent in a fluidized bed reactor

    International Nuclear Information System (INIS)

    Highlights: • CaO coating at atmospheric pressure is applied on silica nanoparticles in a fluidized bed. • Atmospheric pressure would facilitate scaling-up of the process. • The conditions for the coating process at atmospheric pressure are discussed. • The CO2 sorbent capacity is demonstrated by TGA in carbonation/calcination. • STEM-EDX shows the presence of CaO on the surface of the nanoparticles. - Abstract: CaO has been deposited on a nanosilica powder matrix by a procedure based on atomic layer deposition (ALD) in a fluidized bed reactor at atmospheric pressure following a potentially scalable process. In previous works ALD in gas fluidized bed has been mostly performed under reduced pressure, which hampers scaling-up the production technology. The material synthesized in the present work is tested as CO2 solid sorbent at calcium looping conditions. Multicyclic thermogravimetric analysis (TGA) shows that the nanosilica support stabilizes the capture capacity of CaO. EDX-STEM analysis illustrates the presence of Ca well distributed on the surface of the SiO2 nanoparticles

  2. The calcination and sulphation behaviour of sorbents in fluidized bed combustion

    Energy Technology Data Exchange (ETDEWEB)

    Haji-Sulaiman, M.Z.; Scaroni, A.W. (Pennsylvania State University, University Park, PA (USA). Combustion Laboratory)

    1991-02-01

    A study was performed on the effects of the CO{sub 2} partial pressure in the calcining gas and sorbent impurities on the structure of calcines produced and on subsequent sulphation behaviour under fluidized bed combustion conditions. It was found that the average pore size and the BET surface area were affected markedly by these two parameters, but their effect on pore volume was not significant. Increasing both parameters increased the average pore size and decreased the surface area as a consequence of sintering. During sulphation the presence of impurities delayed pore closure due to the formation of CaSO{sub 4}. Hence, higher calcium utilization was achieved from the lower purity stones. The results highlight the importance of considering chemical composition in addition to initial physical properties in the selection of sorbents for use during fluidized bed coal combustion, since chemical composition controls, to a large extent, the physical properties developed upon calcination, and the structure of the calcine affects sulphation behaviour. 30 refs., 7 figs., 2 tabs.

  3. LIFAC sorbent injection desulfurization demonstration project. Final report, volume II: Project performance and economics

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-01-01

    This publication discusses the demonstration of the LIFAC sorbent injection technology at Richmond Power and Light`s Whitewater Valley Unit No. 2, performed under the auspices of the U.S. Department of Energy`s (DOE) Clean Coal Technology Program. LIFAC is a sorbent injection technology capable of removing 75 to 85 percent of a power plant`s SO{sub 2} emissions using limestone at calcium to sulfur molar ratios of between 2 and 2.5 to 1. The site of the demonstration is a coal-fired electric utility power plant located in Richmond, Indiana. The project is being conducted by LIFAC North America (LIFAC NA), a joint venture partnership of Tampella Power Corporation and ICF Kaiser Engineers, in cooperation with DOE, RP&L, and Research Institute (EPRI), the State of Indiana, and Black Beauty Coal Company. The purpose of Public Design Report Volume 2: Project Performance and Economics is to consolidate, for public use, the technical efficiency and economy of the LIFAC Process. The report has been prepared pursuant to the Cooperative Agreement No. DE-FC22-90PC90548 between LIFAC NA and the U.S. Department of Energy.

  4. In-duct sorbent injection for CO{sub 2} capture

    Energy Technology Data Exchange (ETDEWEB)

    Gemma Grasa; Nigel Simms; John Oakey; Juan Carlos Abanades [Cranfield University, Cranfield (United Kingdom). Power Generation Technology Centre

    2005-07-01

    The work presented in this poster is based on the use of a carbonation/calcination cycle to separate CO{sub 2} from combustion gases using lime as an effective sorbent to form calcium carbonate. Various options are possible when integrating the components of this cycle into a combustion plant. One of these options involves the direct injection of fine lime particles into the exhaust duct of a boiler. This configuration has been studied at laboratory and pilot scale with CO{sub 2} reductions in the order of 30-40% within a few seconds of nominal particle residence time. This option is shown to be of interest for retrofitting, requiring modest modifications in the plant layout. 3 refs., 4 figs., 1 tab.

  5. Molten iron oxysulfide as a superior sulfur sorbent. Final report, [September 1989--1993

    Energy Technology Data Exchange (ETDEWEB)

    Hepworth, M.T.

    1993-03-31

    The studies had as original objective the analysis of conditions for using liquid iron oxysulfide as a desulfuring agent during coal gasification. Ancillary was a comparison of iron oxysulfide with lime as sorbents under conditions where lime reacts with S-bearing gases to form Ca sulfate or sulfide. Primary thrust is to determine the thermodynamic requirements for desulfurization by iron additions (e.g., taconite concentrate) during combustion in gasifiers operating at high equivalence ratios. Thermodynamic analysis of lime-oxygen-sulfur system shows why lime is injected into burners under oxidizing conditions; reducing conditions forms CaS, requiring its removal, otherwise oxidation and release of S would occur. Iron as the oxysulfide liquid has a range of stability and can be used as a desulfurizing agent, if the burner/gasifier operates in a sufficiently reducing regime (high equivalence ratio); this operating range is given and is calculable for a coal composition, temperature, stoichiometry. High moisture or hydrogen contents of the coal yield a poorer degree of desulfurization. Kinetic tests on individual iron oxide particles on substrates or Pt cups with a TGA apparatus fail to predict reaction rates within a burner. Preliminary tests on the Dynamic Containment Burner with acetylene give some promise that this system can produce the proper conditions of coal gasification for use of added iron as a sulfur sorbent.

  6. 木素稀硝酸氧化及其与磷酸钙作用的研究%Study on oxidation of lignin by nitric acid and its reaction with calcium phosphate

    Institute of Scientific and Technical Information of China (English)

    马子川; 崔振水

    2001-01-01

    研究了造纸黑液木素稀硝酸氧化法制备活性氧化木素的适宜条件。结果表明,当磷酸含量为4.0%,木素与稀硝酸的质量配比为1∶10,可得到腐殖酸含量达46%的氧化木素。研究了氧化木素和氨化氧化木素对3种磷酸钙的溶解性的影响,讨论并合理地解释了反应机理。%Optimal conditions for preparation of active lignin oxide by oxidizing black-liquor lignin with nitric acid were studied.The results showed that the yield of lignin oxide was up to 46% when the concentration of phosphoric acid was under 4.0%,and the mass ratio of lignin to diluted nitric acid was 1∶10.Effects on solubilities of three kinds of calcium phosphate and ammoniated oxidized lignin were observed and reasonable reaction mechanism was discussed.

  7. High Calcium Diet Affects Serum Nitric Oxide Concentration and Antioxidant Function of Pullets%高钙饲粮对青年蛋鸡血清一氧化氮浓度和抗氧化功能的影响

    Institute of Scientific and Technical Information of China (English)

    郭小权; 黄克和; 曹华斌; 胡国良; 李浩棠; 张彩英

    2012-01-01

    本试验旨在研究高钙饲粮对青年蛋鸡血清一氧化氮(NO)浓度和抗氧化功能的影响.将35日龄100羽伊沙蛋鸡随机均分为对照组(含钙1.00%)和高钙组(含钙3.78%),每组5个重复,每个重复10羽.每天观察鸡的精神状态、食欲和粪便情况.在饲喂高钙饲粮第0、8、16、24和32天时,分别测定2组鸡的血清中NO浓度和丙二醛含量及抗氧化酶系统的变化.结果表明:1)高钙饲粮能引起青年蛋鸡长期腹泻,在饲喂高钙饲粮的第8天就发生高血钙症.2)与对照组相比,高钙组在饲喂高钙饲粮第8天和第16天血清NO浓度无显著变化(P>0.05),第24天和第32天显著升高(P<0.05);第8天和第24天血清超氧化物歧化酶活性、总抗氧化能力无显著变化(P>0.05),第16天显著升高(P<0.05),第32天显著降低(P<0.05);第8、16、24天血清丙二醛含量无显著变化(P>0.05),第32天显著升高(P<0.05);第24天和第32天黄嘌呤氧化酶活性有升高趋势(P>0.05).结果提示,饲喂高钙饲粮可导致青年蛋鸡发生长期腹泻,引起高血钙症,导致其机体内自由基的产生与清除的动态平衡遭到破坏,使自由基的产生远远超出清除能力.%This experiment was conducted to study the effects of high calcium diet on nitric oxide (NO) concentration and antioxidant function of pullets. One hundred healthy pullets aged 35 days were randomly divided into 2 groups with 5 replicates in each group and 10 chickens per replicate. The pullets in different groups were fed normal calcium diet (control group, 1. 00% calcium) and high calcium diet (HC group, 3. 78% calcium) , respectively. Healthy situations of the pullets were inspected daily. NO concentration, malondialdehyde (MDA) content and enzymatic antioxidant activity in serum were detected on days 0, 8, 16, 24 and 32 after feeding high calcium diet. The results showed as follows: 1) high calcium diet could cause diarrhea. Pullets would be hypercalcemia

  8. Involvement of reactive oxygen species and high-voltage-activated calcium currents in nanoparticle zinc oxide-induced cytotoxicity in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Zhao Jingxia [Nankai University, College of Medicine (China); Yao Yang [Tianjin First Central Hospital (China); Liu Shichang [Nankai University, College of Medicine (China); Zhang Tao [Nankai University, College of Life Science (China); Ren Guogang [University of Hertfordshire, Science and Technology Research Institute (United Kingdom); Yang Zhuo, E-mail: zhuoyang@nankai.edu.cn [Nankai University, College of Medicine (China)

    2012-11-15

    This study was to determine the possible neurotoxicity and mechanisms underlying the effects of nano-ZnO with sizes of 20-80 nm on central nervous system (CNS). The cytotoxicity of nano-ZnO was investigated in PC12 cells. The viability of cells was observed by a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, and the generation of reactive oxygen species (ROS) for cells was evaluated by a fluorometry assay. The apoptosis of cells was detected and analyzed by flow cytometry. In addition, effects of nano-ZnO on the properties of high-voltage-activated (HVA) calcium currents were studied in acutely isolated rat hippocampal pyramidal neurons using the whole-cell patch clamp technique. The results of MTT assay showed that nano-ZnO (10{sup -4} g/mL) caused a significant decrease in cell viability (P < 0.05). Nano-ZnO induced intracellular accumulation of ROS and the apoptosis of PC12 cells with the increasing concentration of nano-ZnO in flow cytometric assay (P < 0.05). Further results of electrophysiological recording indicated that 10{sup -4} g/mL nano-ZnO first altered the current-voltage curve and the peak amplitudes of HVA calcium currents at 10 min of the recording, and the peak current amplitudes were increased significantly at the end of 30 min (P < 0.05). All these results suggested that the increase of intracellular ROS was one of potential mechanisms of cellular apoptosis induced by nano-ZnO. Nano-ZnO could cause the elevation of cytosolic calcium levels by enhancement of HVA calcium currents, which would increase the generation of intracellular ROS, and consequently promote the neuronal apoptosis.

  9. Involvement of reactive oxygen species and high-voltage-activated calcium currents in nanoparticle zinc oxide-induced cytotoxicity in vitro

    International Nuclear Information System (INIS)

    This study was to determine the possible neurotoxicity and mechanisms underlying the effects of nano-ZnO with sizes of 20–80 nm on central nervous system (CNS). The cytotoxicity of nano-ZnO was investigated in PC12 cells. The viability of cells was observed by a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, and the generation of reactive oxygen species (ROS) for cells was evaluated by a fluorometry assay. The apoptosis of cells was detected and analyzed by flow cytometry. In addition, effects of nano-ZnO on the properties of high-voltage-activated (HVA) calcium currents were studied in acutely isolated rat hippocampal pyramidal neurons using the whole-cell patch clamp technique. The results of MTT assay showed that nano-ZnO (10−4 g/mL) caused a significant decrease in cell viability (P −4 g/mL nano-ZnO first altered the current–voltage curve and the peak amplitudes of HVA calcium currents at 10 min of the recording, and the peak current amplitudes were increased significantly at the end of 30 min (P < 0.05). All these results suggested that the increase of intracellular ROS was one of potential mechanisms of cellular apoptosis induced by nano-ZnO. Nano-ZnO could cause the elevation of cytosolic calcium levels by enhancement of HVA calcium currents, which would increase the generation of intracellular ROS, and consequently promote the neuronal apoptosis.

  10. Comportamento ingestivo em caprinos alimentados com dietas contendo cana-de-açúcar tratada com óxido de cálcio Ingestive behavior in goats fed diets containing sugar cane treated with calcium oxide

    Directory of Open Access Journals (Sweden)

    Gleidson Giordano Pinto de Carvalho

    2011-08-01

    Full Text Available Objetivou-se avaliar o efeito do tratamento da cana-de-açúcar com óxido de cálcio (CaO sobre o comportamento ingestivo em caprinos. Foram utilizados oito caprinos da raça Saanen, machos castrados, com peso corporal médio de 22,6 kg e 4 meses de idade, distribuídos em dois quadrados latinos 4 × 4, com quatro períodos experimentais de 14 dias. Os animais foram mantidos em baias individuais de 1,2 m², com piso ripado de madeira, providas de comedouros e bebedouros individuais. As dietas foram formuladas para ser isoproteicas e conter 14% de proteína bruta (PB e apresentaram 70% de cana-de-açúcar tratada com 0; 0,75; 1,5 ou 2,25% de óxido de cálcio (com base na matéria natural corrigida com 1% de ureia e 30% de concentrado fornecidas a vontade. A cana-de-açúcar com a adição das doses de óxido de cálcio, foi triturada em desintegradora estacionária, pesada e acondicionada em baldes plásticos de 50 L, tratada com o óxido de cálcio e fornecida aos animais após 24 horas de armazenamento. Os tempos despendidos em alimentação, ruminação (min/dia, min/kg MS e min/kg FDN e ócio (min/dia não foram afetados pela adição de óxido de cálcio à cana-de-açúcar. A adição de óxido de cálcio à cana-de-açúcar não influenciou a eficiência em alimentação e ruminação, mas provocou redução do tempo médio despendido por período de alimentação. O comportamento ingestivo de caprinos em crescimento não é afetado pela utilização de dietas contendo cana-de-açúcar tratada com até 2,25% de óxido de cálcio.The objective of this work was to evaluate the effect of sugar cane treated with calcium oxide (CaO on ingestive behavior in goats. It was used eight castrated male Saanen goats, with 22.6 kg average body weight and at four months of age, distributed in two 4 × 4 Latin squares, with four 14-day experimental periods. The animals were kept in individual 1.2-m² stalls, with wood battened floor, provided with

  11. CARBON DIOXIDE CAPTURE FROM FLUE GAS USING DRY REGENERABLE SORBENTS

    Energy Technology Data Exchange (ETDEWEB)

    David A. Green; Thomas Nelson; Brian S. Turk; Jeffrey W. Portzer; Raghubir P. Gupta

    2005-04-01

    This report describes research conducted between January 1, 2005 and March 31, 2005 on the use of dry regenerable sorbents for removal of carbon dioxide from flue gas. Engineered sorbents composed of sodium carbonate on a ceramic support were tested in a laboratory fluidized bed reactor system and found to be capable of essentially complete removal of carbon dioxide at 60 C in a short residence time. Upon breakthrough the sorbents can be thermally regenerated to recover essentially all of the absorbed carbon dioxide. An optimized supported sorbent tested in a pilot-scale entrained bed absorber retained its reactivity in multicycle tests and experienced no attrition. Removal of >90% of carbon dioxide in simulated flue gas was achieved in an entrained bed reactor.

  12. CO2 capture at ambient temperature in a fixed bed with CaO-based sorbents

    International Nuclear Information System (INIS)

    Highlights: • CaO-based pellets can be used for CO2 capture at ambient temperature. • Pre-hydration of pellets improves CO2 capture capacity significantly. • CO2 capture capacity of 0.5 g/g is obtained in a CaO-based fixed bed. • The capture capacity is sensitive to moisture and CO2 inlet concentration. - Abstract: This work investigates post-combustion CO2 capture at ambient temperature in a fixed bed by means of CaO-based sorbents. Two sorbents were used: limestone and pellets prepared from powdered limestone using calcium aluminate cement as a binder. The results showed that pre-hydration had a significant effect on CO2 capture performance of the two sorbents. For instance, after 8 h pre-hydration, the breakthrough time increased from 21 min to 660 min for lime, and from 19 min to 750 min for pellets. The performance of pellets was more sensitive to hydration conditions than for the lime. At breakthrough, full carbonation conversion over half of the reactor was achieved in a pre-hydrated bed of pellets exposed to a feed with 0.5% CO2, resulting in an average specific capture of 0.51 g CO2/g bed material. This was considered a sufficient capture performance, with a distinct mass transfer zone (MTZ) located in the upper half of the reactor. However, increasing CO2 inlet concentration to 2% shortened the breakthrough time and shifted the MTZ toward the entrance zone of the reactor. It was concluded that capturing CO2 from low-CO2 flue gases at ambient temperature using a fixed bed of pre-hydrated CaO-based pellets is a promising approach that has the potential to achieve reasonable capture performance at relatively low cost. The proposed process can be used for CO2 capture from CO2-depleted flue gases (residual CO2) from processes such as amine scrubbing and calcium looping. And it would allow for the possibility that capture could be increased to any given level required by new legislation for plant with carbon capture

  13. Water purification from radionuclides with using fibroid sorbents

    International Nuclear Information System (INIS)

    Full text: Purification waste water and drinking water from radionuclides, heavy metal ions, organic contamination is one of the important problems today. For solving this problem we have created three types of fibroid sorbents on the base of Polyester: cationic and anionic exchange and carbonic. Main properties of these sorbents are described in this article. For example characteristics of the sorbents for removing radionuclides Co-60,57, Zn-65, Sr-89,90, Cs-134,137, etc., radionuclides containing organic molecules M-P-32, M-I-131, M-Mo-99+Tc-99m, M-C-14, etc., heavy metal ions Zn, Ni, Cu, Sb, Pb, Cd, Cr, U, etc., organic molecules (pesticides, phenols, dioxin, benzene, toluene, etc.) were investigated. Influence of pH on percent removal, influence of K, Na and another ions concentrations in the liquid on the percent removal, decreasing of the saturation capacity from number of regeneration and another characteristics are described. Static exchange capacity of the cationic sorbents is 1-2 mg-equ/g and anionic - 0.5-1 mg-equ/g. Capacity of the carbonic sorbents for benzene is 100 mg/g. Time of chemical balance setting is 1-2 s. The sorbents are effective in removing the low concentrations of contamination from the water (lower than 100-200 mg/l) and the air (lower than 100 mg/m3). The use of sorbents in drinking water filters and mini-systems is described. The industrial water purification system consists of coagulating unit, sorbent unit and disinfectant unit. The systems are used in atomic power stations, electroplating plants, matches plants, leather and skin treating plants, car-washing stations, etc

  14. Use of sorbents in air quality control systems

    OpenAIRE

    Gallego Piñol, Eva; Roca Mussons, Francisco Javier; Perales Lorente, José Francisco; Guardino Solà, Xavier

    2009-01-01

    Sorbent based methods have been successfully used in the collection of air samples to determine air quality. The complexity of the occurrence in air samples of several compounds in terms of composition (polar to non-polar compounds, very volatile to semi-volatile compounds) and abundance (below detection limit to over detector saturation limit) are topics that have to be taken into account when analytical methods are developed, especially in terms of sorbent choosing. An important amount o...

  15. Industrial management of peat sorbent production in Tomsk region

    International Nuclear Information System (INIS)

    The intensification of production development causes the growth of energy consumption and increases the risk of oil leak. This involves the implementation of measures for the effective breakdown elimination. In this case the best method meeting the environmental requirements is the use of appropriate sorbent. The economic research of using the peat sorbent by oil and gas extraction companies in Tomsk region was carried out

  16. Calcium and Vitamin D

    Science.gov (United States)

    ... Home › Patients › Treatment › Calcium/Vitamin D Calcium/Vitamin D Getting enough calcium and vitamin D is essential ... counter medications and calcium supplements. What is Vitamin D and What Does it Do? Vitamin D plays ...

  17. Engineered sorbent barriers for low-level waste disposal

    International Nuclear Information System (INIS)

    The Engineered Sorbent Barriers Program at Pacific Northwest Laboratory is investigating sorbent materials to prevent the migration of soluble radio nuclides from low-level waste sites. These materials would allow water to pass, preventing the bathtub effect at humid sites. Laboratory studies identifield promising sorbent materials for three key radionuclides: for cesium, greensand; for cobalt, activated charcoal; and for strontium, synthetic zeolite or clinoptilolite. Mixtures of these sorbent materials were tested in 0.6-m-diameter columns using radioactive leachates. To simulate expected worst-case conditions, the leachate solution contained the radionuclides, competing cations, and a chelating agent and was adjusted to a pH of 5. A sorbent barrier comprised of greensand (1 wt%), activated charcoal (6 wt%), synthetic zeolite (20 wt%), and local soil (73 wt%) achieved the decontamination factors necessary to meet the regulatory performance requirements established for this study. Sorbent barriers can be applied to shallow-land burial, as backfill around the waste or engineered structures, or as backup to other liner systems. 7 refs., 14 figs., 12 tabs

  18. CARBON DIOXIDE CAPTURE FROM FLUE GAS USING DRY REGENERABLE SORBENTS

    Energy Technology Data Exchange (ETDEWEB)

    David A. Green; Brian S. Turk; Jeffrey W. Portzer; Raghubir P. Gupta; William J. McMichael; Ya Liang; Douglas P. Harrison

    2003-01-01

    The objective of this project is to develop a simple and inexpensive process to separate CO{sub 2} as an essentially pure stream from a fossil fuel combustion system using a regenerable sorbent. The sorbents being investigated in this project are primarily alkali carbonates, and particularly sodium carbonate and potassium carbonate, which are converted to bicarbonates or intermediate salts through reaction with carbon dioxide and water vapor. Bicarbonates are regenerated to carbonates when heated, producing a nearly pure CO{sub 2} stream after condensation of water vapor. This quarter, electrobalance tests suggested that high calcination temperatures decrease the activity of sodium bicarbonate Grade 1 (SBC No.1) during subsequent carbonation cycles, but there is little or no progressive decrease in activity in successive cycles. SBC No.1 appears to be more active than SBC No.3. As expected, the presence of SO{sub 2} in simulated flue gas results in a progressive loss of sorbent capacity with increasing cycles. This is most likely due to an irreversible reaction to produce Na{sub 2}SO{sub 3}. This compound appears to be stable at calcination temperatures as high as 200 C. Tests of 40% supported potassium carbonate sorbent and plain support material suggest that some of the activity observed in tests of the supported sorbent may be due to adsorption by the support material rather than to carbonation of the sorbent.

  19. Importance of Calcium

    OpenAIRE

    TANDOĞAN, Berivan; ULUSU, N. Nuray

    2005-01-01

    Calcium is the most abundant mineral in the body. Calcium regulates many cellular processes and has important structural roles in living organisms. Skeletal muscle structure and function, polymerisation of fibrin and the conduction of impulses in the nervous system are regulated by calcium. Calcium is an important intracellular messenger in protozoa, plants, and animals. Calcium-transporting systems which are located in the plasma membrane and in the organelles, regulate the ionic concentrati...

  20. New Sorbents for Removing Arsenic From Water

    Science.gov (United States)

    McConchie, D. M.; Genc-Fuhrman, H.; Clark, M. W.; Caldicott, W.; Davies-McConchie, F. G.

    2004-12-01

    Elevated concentrations of arsenic in the drinking water used in many countries, including some of the poorest developing countries, and recognition that consuming this water can have serious consequences for human health, have led to increased investigations of ways to obtain safe water supplies. Finding new groundwater resources is a possible solution but this is a costly strategy that has no guarantee of success, particularly in areas where water is already a scarce commodity. The alternative is to treat water that is already available, but existing technologies are usually too expensive, too difficult to operate and maintain, or not completely effective when used in less developed countries or remote areas. There is therefore, an urgent need to find a simple and effective but inexpensive sorbent for arsenic that can be used to treat large volumes of water under less than ideal conditions. In this paper we present the results of field and laboratory trials that used a new, highly cost-effective, sorbent to remove arsenic from contaminated water. BauxsolT is the name given to the cocktail of minerals prepared by treating caustic bauxite refinery residues with Mg and Ca to produce a substance with a reaction pH of about 8.5, a high acid neutralizing capacity and an excellent ability to trap trace metals, metalloids and some other ionic species. The trapped ions are tightly bound by processes that include; precipitation of low solubility neoformational minerals, isomorphous substitution, solid-state diffusion, and adsorption; it is also an excellent flocculant. Although ordinary BauxsolT has an excellent ability to bind arsenate, and to a lesser extent arsenite, this ability can be further increased for particular water types by using activated BauxsolT or BauxsolT combined with small amounts of other reagents. Field trials conducted at the Gilt Edge Mine, South Dakota, showed that the addition of BauxsolT to highly sulfidic waste rock reduced the arsenic

  1. Conversion coatings prepared or treated with calcium hydroxide solutions

    Science.gov (United States)

    Minevski, Zoran (Inventor); Clarke, Eric (Inventor); Maxey, Jason (Inventor); Nelson, Carl (Inventor); Eylem, Cahit (Inventor)

    2002-01-01

    A conversion coating process that forms a stable and corrosion-resistant oxide layer on metal or metal oxide substrates or layers. Particularly, the conversion coating process involves contacting the metal or metal oxide substrate or layer with the aqueous calcium hydroxide solutions in order to convert the surface of the substrate to a stable metal oxide layer or coating. According to the present invention, the calcium hydroxide solution is prepared by removing carbon dioxide from water or an aqueous solution before introducing the calcium hydroxide. In this manner, formation of calcium carbonate particles is avoided and the porosity of the conversion coating produced by the calcium hydroxide solution is reduced to below about 1%.

  2. Evaluation of Sorbent Injection for Mercury Control

    Energy Technology Data Exchange (ETDEWEB)

    Sharon Sjostrom

    2006-04-30

    The power industry in the U.S. is faced with meeting new regulations to reduce the emissions of mercury compounds from coal-fired plants. These regulations are directed at the existing fleet of nearly 1,100 boilers. These plants are relatively old with an average age of over 40 years. Although most of these units are capable of operating for many additional years, there is a desire to minimize large capital expenditures because of the reduced (and unknown) remaining life of the plant to amortize the project. Injecting a sorbent such as powdered activated carbon into the flue gas represents one of the simplest and most mature approaches to controlling mercury emissions from coal-fired boilers. This is the final site report for tests conducted at DTE Energy's Monroe Power Plant, one of five sites evaluated in this DOE/NETL program. The overall objective of the test program was to evaluate the capabilities of activated carbon injection at five plants: Sunflower Electric's Holcomb Station Unit 1, AmerenUE's Meramec Station Unit 2, Missouri Basin Power Project's Laramie River Station Unit 3, Detroit Edison's Monroe Power Plant Unit 4, and AEP's Conesville Station Unit 6. These plants have configurations that together represent 78% of the existing coal-fired generation plants. The goals for the program established by DOE/NETL were to reduce the uncontrolled mercury emissions by 50 to 70% at a cost 25 to 50% lower than the target established by DOE of $60,000/lb mercury removed. The results from Monroe indicate that using DARCO{reg_sign} Hg would result in higher mercury removal (80%) at a sorbent cost of $18,000/lb mercury, or 70% lower than the benchmark. These results demonstrate that the goals established by DOE/NETL were exceeded during this test program. The increase in mercury removal over baseline conditions is defined for this program as a comparison in the outlet emissions measured using the Ontario Hydro method during the baseline

  3. CaO-based pellets supported by calcium aluminate cements for high-temperature CO2 capture.

    Science.gov (United States)

    Manovic, Vasilije; Anthony, Edward J

    2009-09-15

    The development of highly efficient CaO-based pellet sorbents, using inexpensive raw materials (limestones) or the spent sorbent from CO2 capture cycles, and commercially available calcium aluminate cements (CA-14, CA-25, Secar 51, and Secar 80), is described here. The pellets were prepared using untreated powdered limestones or their corresponding hydrated limes and were tested for their CO2 capture carrying capacities for 30 carbonation/calcination cycles in a thermogravimetric analyzer (TGA). Their morphology was also investigated by scanning electron microscopy (SEM) and their compositions before and after carbonation/calcination cycleswere determined by X-ray diffraction (XRD). Pellets prepared in this manner showed superior behavior during CO2 capture cycles compared to natural sorbents, with the highest conversions being > 50% after 30 cycles. This improved performance was attributed to the resulting substructure of the sorbent particles, i.e., a porous structure with nanoparticles incorporated. During carbonation/calcination cycles mayenite (Ca12Al14O33) was formed, which is believed to be responsible for the favorable performance of synthetic CaO-based sorbents doped with alumina compounds. An added advantage of the pellets produced here is their superior strength, offering the possibility of using them in fluidized bed combustion (FBC) systems with minimal sorbent loss due to attrition. PMID:19806751

  4. Molten iron oxysulfide as a superior sulfur sorbent

    Energy Technology Data Exchange (ETDEWEB)

    Hepworth, M.T.

    1990-01-01

    Slagging combustors with injected lime or limestone are being considered as replacements for conventional coal burners. They have advantages in that they can be staged to reduce NO{sub x} and SO{sub x} emissions. Iron oxide, as an alternative to lime or limestone may be effective not only as a desulfurizing agent, but, under the right conditions of oxygen potential, it can act as a flux to produce a glassy slag. This glassy slag should be dense and environmentally inert. In this reporting period, the thermodynamic conditions are determined for the operation of the first stage of a combustor which would have as its feed six types of coals. The calculations are made for the four phase equilibrium: FeO(wustite)/Fe/Liquid/Gas over the temperature range 950{degrees} to 1300{degrees}C. The minimum dosage of iron oxide required at equilibrium an the calculated maximum percent sulfur removal are reported. Also given are the expected pounds of S0{sub 2} per million Btu of heat evolution calculated for complete combustion. These preliminary results indicate in the Fe-O-S system that higher temperatures give better results approaching 96 percent sulfur removal from a coal containing (on a dry basis) 3.29% by weight sulfur. In the prior reporting period, a comparison is made between iron oxide and lime as a desulfurizing agent. With lime, the thermodynamic conditions were chosen: a set of conditions where the compound calcium sulfide is the product and a set of conditions where calcium sulfate is the product. The temperature limits of the sulfate forming and sulfide forming reactions were defined.

  5. Preparation of a calcium-substituted copper-rich yttrium barium copper oxide superconductor from a spray-dried nitrate precursor

    International Nuclear Information System (INIS)

    A calcium-substituted YBa2Cu4O8 (1-2-4) high-temperature superconductor is synthesized from a precursor obtained by spray-drying of a nitrate solution containing the corresponding metals in a stoichiometric ratio. The synthesis takes place during one-stage heat-treatment of the precursor at 800 C in an oxygen flow under a pressure of 1 atm within a relatively short period of time, additives as well as intermediate grinding and pressing of the products being not needed. Measurements of the a.c. susceptibility have revealed a very sharp superconducting transition which is comparable with that of samples prepared under a high pressure. The transition in Ca-substituted YBa2Cu4O8 occurs at a temperature by about 8 K higher than Tc of the Ca-free phase. Raman spectra suggest that during the substitution calcium does not occupy barium positions in the YBa2Cu4O8 lattice

  6. Oxidation of Mercury in Products of Coal Combustion

    Energy Technology Data Exchange (ETDEWEB)

    Peter Walsh; Giang Tong; Neeles Bhopatkar; Thomas Gale; George Blankenship; Conrad Ingram; Selasi Blavo Tesfamariam Mehreteab; Victor Banjoko; Yohannes Ghirmazion; Heng Ban; April Sibley

    2009-09-14

    scale, burning bituminous coals (Gale, 2006) and blends of bituminous coals with Powder River Basin coal (Gale, 2005). The removal of mercury by fly ash and unburned carbon in the flue gas from combustion of the bituminous coals and blends was reproduced with satisfactory accuracy by the model. The enhancement of mercury capture in the presence of calcium (Gale, 2005) explained a synergistic effect of blending on mercury removal across the baghouse. The extent of mercury oxidation, on the other hand, was not so well described by the simulation, because of oversensitivity of the oxidation process in the model to the concentration of unburned carbon. Combined catalysts and sorbents for oxidation and removal of mercury from flue gas at low temperature were based on surfactant-templated silicas containing a transition metal and an organic functional group. The presence of both metal ions and organic groups within the pore structure of the materials is expected to impart to them the ability to simultaneously oxidize elemental mercury and adsorb the resulting oxidized mercury. Twelve mesoporous organosilicate catalysts/sorbents were synthesized, with and without metals (manganese, titanium, vanadium) and organic functional groups (aminopropyl, chloropropyl, mercaptopropyl). Measurement of mercury oxidation and adsorption by the candidate materials remains for future work.

  7. Crocin Suppresses LPS-Stimulated Expression of Inducible Nitric Oxide Synthase by Upregulation of Heme Oxygenase-1 via Calcium/Calmodulin-Dependent Protein Kinase 4

    OpenAIRE

    Ji-Hee Kim; Ga-Young Park; Soo Young Bang; Sun Young Park; Soo-Kyung Bae; YoungHee Kim

    2014-01-01

    Crocin is a water-soluble carotenoid pigment that is primarily used in various cuisines as a seasoning and coloring agent, as well as in traditional medicines for the treatment of edema, fever, and hepatic disorder. In this study, we demonstrated that crocin markedly induces the expression of heme oxygenase-1 (HO-1) which leads to an anti-inflammatory response. Crocin inhibited inducible nitric oxide synthase (iNOS) expression and nitric oxide production via downregulation of nuclear factor k...

  8. Spill sorbents: A comparison of water and oil sorbency

    International Nuclear Information System (INIS)

    Sorbents for oil spills come in three general classes: organic, such as peat moss, sawdust, and paper fibre; inorganic, such as clay, vermiculite, and diatomaceous earth; and synthetic, including a variety of materials made from polymers such as polyethylene and polypropylene. The water and oil sorptive properties of various sorbents are listed and their characteristics are described. In spill remediation, most synthetic adsorbents are oleophilic with some degree of hydrophobic properties to prevent them from taking up water as they clean up the oil. In some situations, such as maintenance spills where aqueous liquids are also encountered, universal sorbents which have both oleophilic and hydrophilic properties are used. Sorbents are sold in a variety of product configurations, including powders, beads, rolls, ropes, and booms. Melt blown polypropylene is widely used since it is inexpensive, easy to apply, a good insulator, relatively inert, non-hazardous, and available in a wide variety of configurations. Its approximate oil sorbency is 20-30 times its own weight while its water sorbency is 0.0-0.1 times its own weight. In the Canadian market, sorbent products are available from importers, packagers, and manufacturers. The market is dominated by a few large companies that provide a range of high- and low-tech products in addition to ancillary products such as drums and skimmers. 2 tabs

  9. CARBON DIOXIDE CAPTURE FROM FLUE GAS USING DRY REGENERABLE SORBENTS

    Energy Technology Data Exchange (ETDEWEB)

    David A. Green; Brian S. Turk; Jeffrey W. Portzer; Raghubir P. Gupta; William J. McMichael; Ya Liang; Tyler Moore; Douglas P. Harrison

    2003-08-01

    This report describes research conducted between April 1, 2003 and June 30, 2003 on the use of dry regenerable sorbents for concentration of carbon dioxide from flue gas. Grade 1 sodium bicarbonate performed similarly to grade 5 sodium bicarbonate in fixed bed testing in that activity improved after the first carbonation cycle and did not decline over the course of 5 cycles. Thermogravimetric analysis indicated that sodium bicarbonate sorbents produced by calcination of sodium bicarbonate are superior to either soda ash or calcined trona. Energy requirements for regeneration of carbon dioxide sorbents (either wet or dry) is of primary importance in establishing the economic feasibility of carbon dioxide capture processes. Recent studies of liquid amine sorption processes were reviewed and found to incorporate conflicting assumptions of energy requirements. Dry sodium based processes have the potential to be less energy intensive and thus less expensive than oxygen inhibited amine based systems. For dry supported sorbents, maximizing the active fraction of the sorbent is of primary importance in developing an economically feasible process.

  10. Dual layer hollow fiber sorbents: Concept, fabrication and characterization

    KAUST Repository

    Bhandari, Dhaval

    2013-02-01

    Hollow fiber sorbents are pseudo-monolithic separations materials created with fiber spinning technology using a polymer \\'binder\\', impregnated with high loadings of sorbent \\'fillers\\' [1]. To increase purified gas recovery during the sorption step and to ensure consistent sorption capacity over repeated cycles, a dense, thin polymer barrier layer on the fiber sorbents is needed to allow only thermal interactions between the sorbate loaded layer and the thermal regeneration fluid. This paper considers materials and methods to create delamination-free dual layer fiber sorbents, with a porous core and a barrier sheath layer formed using a simultaneous co-extrusion process. Low permeability polymers were screened for sheath layer creation, with the core layer comprising cellulose acetate polymer as binder and zeolite NaY as sorbent fillers. Appropriate core and sheath layer dope compositions were determined by the cloud-point method and rheology measurements. The morphology of the as-spun fibers was characterized in detail by SEM, EDX and gas permeation analysis. A simplified qualitative model is described to explain the observed fiber morphology. The effects of core, sheath spin dope and bore fluid compositions, spinning process parameters such as air-gap height, spin dope and coagulation bath temperatures, and elongation draw ratio are examined in detail. © 2012 Elsevier B.V. All rights reserved.

  11. Facile synthesis of Fe3O4 nanoparticles decorated on 3D graphene aerogels as broad-spectrum sorbents for water treatment

    Science.gov (United States)

    Li, Yong; Zhang, Ruofang; Tian, Xike; Yang, Chao; Zhou, Zhaoxin

    2016-04-01

    In order to develop efficient and environment benign sorbents for water purification, the macroscopic multifunctional magnetite-reduced graphene oxides aerogels (M-RGOs) with strong interconnected networks were prepared via a one pot solvothermal method of graphene oxide sheets adsorbing iron ions and in situ simultaneous deposition of Fe3O4 nanoparticles in ethylene glycol or triethylene glycol solvents. Such M-RGOs exhibited excellent sorption capacity to different contaminants, including oils, organic solvents, arsenite ions, as well as dyes. In addition, it was demonstrated that the M-RGOs could be used as column packing materials to manufacture column for water purification by filtration. The method proposed was proved to be versatile to induce synergistic assembly of RGO sheets with other functional metal oxides nanoparticles and as a kind of broad-spectrum sorbents for removing different types of contaminants in water purification, simultaneously.

  12. Calcium in diet

    Science.gov (United States)

    ... best source. Milk and dairy products such as yogurt, cheeses, and buttermilk contain a form of calcium ... the amount of calcium in a dairy product. Yogurt, most cheeses, and buttermilk are excellent sources of ...

  13. Fenoprofen calcium overdose

    Science.gov (United States)

    Fenoprofen calcium is a type of medicine called a nonsteroidal anti-inflammatory drug. It is a prescription pain medicine used to relieve symptoms of arthritis . Fenoprofen calcium overdose occurs when someone takes more than the ...

  14. Calcium channel blocker overdose

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/002580.htm Calcium channel blocker overdose To use the sharing features on this page, please enable JavaScript. Calcium channel blockers are a type of medicine used ...

  15. Fenoprofen calcium overdose

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/002649.htm Fenoprofen calcium overdose To use the sharing features on this page, please enable JavaScript. Fenoprofen calcium is a type of medicine called a nonsteroidal ...

  16. Calcium and magnesium disorders.

    Science.gov (United States)

    Goff, Jesse P

    2014-07-01

    Hypocalcemia is a clinical disorder that can be life threatening to the cow (milk fever) and predisposes the animal to various other metabolic and infectious disorders. Calcium homeostasis is mediated primarily by parathyroid hormone, which stimulates bone calcium resorption and renal calcium reabsorption. Parathyroid hormone stimulates the production of 1,25-dihydroxyvitamin D to enhance diet calcium absorption. High dietary cation-anion difference interferes with tissue sensitivity to parathyroid hormone. Hypomagnesemia reduces tissue response to parathyroid hormone. PMID:24980727

  17. Calcium and Mitosis

    Science.gov (United States)

    Hepler, P.

    1983-01-01

    Although the mechanism of calcium regulation is not understood, there is evidence that calcium plays a role in mitosis. Experiments conducted show that: (1) the spindle apparatus contains a highly developed membrane system that has many characteristics of sarcoplasmic reticulum of muscle; (2) this membrane system contains calcium; and (3) there are ionic fluxes occurring during mitosis which can be seen by a variety of fluorescence probes. Whether the process of mitosis can be modulated by experimentally modulating calcium is discussed.

  18. CAN SORBENT-BASED GAS PHASE AIR CLEANING FOR VOCS SUBSTITUTE FOR VENTILATION IN COMMERCIAL BUILDINGS?

    OpenAIRE

    Fisk, William J.

    2008-01-01

    This paper reviews current knowledge about the suitability of sorbent-based air cleaning for removing volatile organic compounds (VOCs) from the air in commercial buildings, as needed to enable reductions in ventilation rates and associated energy savings. The principles of sorbent air cleaning are introduced, criteria are suggested for sorbent systems that can counteract indoor VOC concentration increases from reduced ventilation, major findings from research on sorbent performance for this...

  19. Synthesis of polymer sorbents on the base of polyethylene mine with the improved properties

    International Nuclear Information System (INIS)

    Full text: A number of polymer sorbents was obtained on the base of polyethylene mine with the improved sorption properties.Have been shown that protonization of functional groups of polymer results in improvement sorption properties of sorbents. The sorption capacity of polymer sorbents obtained on the base completely proton zed polyethylene mine almost twice above as compared to by sorbents synthesized by a customary way was established

  20. Deep Bed Iodine Sorbent Testing FY 2011 Report

    Energy Technology Data Exchange (ETDEWEB)

    Nick Soelberg; Tony Watson

    2011-08-01

    Nuclear fission results in the production of fission products (FPs) and activation products that increasingly interfere with the fission process as their concentrations increase. Some of these fission and activation products tend to evolve in gaseous species during used nuclear fuel reprocessing. Analyses have shown that I129, due to its radioactivity, high potential mobility in the environment, and high longevity (half life of 15.7 million years), can require control efficiencies of up to 1,000x or higher to meet regulatory emission limits. Deep-bed iodine sorption testing has been done to evaluate the performance of solid sorbents for capturing iodine in off-gas streams from nuclear fuel reprocessing plants. The objectives of the FY 2011 deep bed iodine sorbent testing are: (1) Evaluate sorbents for iodine capture under various conditions of gas compositions and operating temperature (determine sorption efficiencies, capacities, and mass transfer zone depths); and (2) Generate data for dynamic iodine sorption modeling. Three tests performed this fiscal year on silver zeolite light phase (AgZ-LP) sorbent are reported here. Additional tests are still in progress and can be reported in a revision of this report or a future report. Testing was somewhat delayed and limited this year due to initial activities to address some questions of prior testing, and due to a period of maintenance for the on-line GC. Each test consisted of (a) flowing a synthetic blend of gases designed to be similar to an aqueous dissolver off-gas stream over the sorbent contained in three separate bed segments in series, (b) measuring each bed inlet and outlet gas concentrations of iodine and methyl iodide (the two surrogates of iodine gas species considered most representative of iodine species expected in dissolver off-gas), (c) operating for a long enough time to achieve breakthrough of the iodine species from at least one (preferably the first two) bed segments, and (d) post-test purging

  1. Carbon Dioxide Capture from Flue Gas Using Dry Regenerable Sorbents

    Energy Technology Data Exchange (ETDEWEB)

    David A. Green; Brian S. Turk; Jeffrey W. Portzer; Raghubir P. Gupta; William J. McMichael; Thomas Nelson; Santosh Gangwal; Ya Liang; Tyler Moore; Margaret Williams; Douglas P. Harrison

    2004-09-30

    Laboratory studies were conducted to investigate dry, regenerable, alkali carbonate-based sorbents for the capture of CO{sub 2} from power plant flue gas. Electrobalance, fixed-bed and fluid-bed reactors were used to examine both the CO{sub 2} capture and sorbent regeneration phases of the process. Sodium carbonate-based sorbents (calcined sodium bicarbonate and calcined trona) were the primary focus of the testing. Supported sodium carbonate and potassium carbonate sorbents were also tested. Sodium carbonate reacts with CO{sub 2} and water vapor contained in flue gas at temperatures between 60 and 80 C to form sodium bicarbonate, or an intermediate salt (Wegscheider's salt). Thermal regeneration of this sorbent produces an off-gas containing equal molar quantities of CO{sub 2} and H{sub 2}O. The low temperature range in which the carbonation reaction takes place is suited to treatment of coal-derived flue gases following wet flue gas desulfurization processes, but limits the concentration of water vapor which is an essential reactant in the carbonation reaction. Sorbent regeneration in an atmosphere of CO{sub 2} and water vapor can be carried out at a temperature of 160 C or higher. Pure CO{sub 2} suitable for use or sequestration is available after condensation of the H{sub 2}O. Flue gas contaminants such as SO{sub 2} react irreversibly with the sorbent so that upstream desulfurization will be required when sulfur-containing fossil fuels are used. Approximately 90% CO{sub 2} capture from a simulated flue gas was achieved during the early stages of fixed-bed reactor tests using a nominal carbonation temperature of 60 C. Effectively complete sorbent carbonation is possible when the fixed-bed test is carried out to completion. No decrease in sorbent activity was noted in a 15-cycle test using the above carbonation conditions coupled with regeneration in pure CO{sub 2} at 160 C. Fluidized-bed reactor tests of up to five cycles were conducted. Carbonation of

  2. CARBON DIOXIDE CAPTURE FROM FLUE GAS USING DRY REGENERABLE SORBENTS

    Energy Technology Data Exchange (ETDEWEB)

    David A. Green; Brian S. Turk; Jeffrey W. Portzer; Raghubir P. Gupta; William J. McMichael; Thomas Nelson

    2004-11-01

    Laboratory studies were conducted to investigate dry, regenerable, alkali carbonate-based sorbents for the capture of CO{sub 2} from power plant flue gas. Electrobalance, fixed-bed and fluid-bed reactors were used to examine both the CO{sub 2} capture and sorbent regeneration phases of the process. Sodium carbonate-based sorbents (calcined sodium bicarbonate and calcined trona) were the primary focus of the testing. Supported sodium carbonate and potassium carbonate sorbents were also tested. Sodium carbonate reacts with CO{sub 2} and water vapor contained in flue gas at temperatures between 60 and 80 C to form sodium bicarbonate, or an intermediate salt (Wegscheider's salt). Thermal regeneration of this sorbent produces an off-gas containing equal molar quantities of CO{sub 2} and H{sub 2}O. The low temperature range in which the carbonation reaction takes place is suited to treatment of coal-derived flue gases following wet flue gas desulfurization processes, but limits the concentration of water vapor which is an essential reactant in the carbonation reaction. Sorbent regeneration in an atmosphere of CO{sub 2} and water vapor can be carried out at a temperature of 160 C or higher. Pure CO{sub 2} suitable for use or sequestration is available after condensation of the H{sub 2}O. Flue gas contaminants such as SO{sub 2} react irreversibly with the sorbent so that upstream desulfurization will be required when sulfur-containing fossil fuels are used. Approximately 90% CO{sub 2} capture from a simulated flue gas was achieved during the early stages of fixed-bed reactor tests using a nominal carbonation temperature of 60 C. Effectively complete sorbent carbonation is possible when the fixed-bed test is carried out to completion. No decrease in sorbent activity was noted in a 15-cycle test using the above carbonation conditions coupled with regeneration in pure CO{sub 2} at 160 C. Fluidized-bed reactor tests of up to five cycles were conducted. Carbonation of

  3. Calcium en cardioplegie

    NARCIS (Netherlands)

    Ruigrok, T.J.C.; Meijler, F.L.

    1985-01-01

    Coronary perfusion with a calcium-free solution, followed by reperfusion with a calcium containing solution, may result in acute myocardial cell death and in irreversible loss of the e1ectrical and mechanical activity of the heart. This phenomenon is known as the calcium paradox. A number of cardiop

  4. Influence of calcium-dependent potassium channel blockade and nitric oxide inhibition on norepinephrine-induced contractions in two forms of genetic hypertension

    Czech Academy of Sciences Publication Activity Database

    Líšková, Silvia; Petrová, M.; Karen, Petr; Kuneš, Jaroslav; Zicha, Josef

    2010-01-01

    Roč. 4, č. 3 (2010), s. 128-134. ISSN 1933-1711 R&D Projects: GA AV ČR(CZ) IAA500110902 Institutional research plan: CEZ:AV0Z50110509 Keywords : potassium channels * nitric oxide * norepinephrine Subject RIV: ED - Physiology Impact factor: 0.931, year: 2010

  5. Natural sorbents as barriers against migration of radionuclides from radioactive waste repositories

    International Nuclear Information System (INIS)

    The sorption properties of Bulgarian inorganic sorbents - clinoptilolite, vermiculite, bentonite, glauconite, celadonite and loess, which can be used as buffer, backfill and sealing materials in radwaste repository are studied. Experimental data about sorption and desorption capacities, radiation and thermal stability of sorbents from different Bulgarian deposits are reported and compared. Clinoptilolite from Beli Plast and its sodium variety from Kostino and Moryantsi is recommended as a barrier against radionuclide migration from radwaste repository due to their high sorption capacity of 137Ce, 90Sr and 60Co. The high selectivity of vermiculite for polyvalent ions (144Ce, 59Fe and 90Sr) gives grounds to include the sorption on vermiculite as a second step in the ion exchange technology for low level laundry waste decontamination. Bentonite is studied as a proposed buffer, backfill and sealing material. Its selectivity for cesium is lower compared to those of clinoptilolite. Thus a tailored-made mixture of bentonite and clinoptilolite will act as a barrier against radionuclides in different oxidation state. Glauconite can be successfully used as a barrier against migration of 144Ce, 90Sr, 54Mn and 65Zn. Loess is also included in the study, as the Kozloduy NPP is sited on loess formation and it is a natural potential site for low and intermediate level waste burial. It is concludes that zeolites and clays of Bulgarian deposits can be used effectively against radionuclide migration from radioactive waste repositories. 59 refs., 5 tabs. (author)

  6. Developing low-cost carbon-based sorbents for Hg capture from flue gas

    Energy Technology Data Exchange (ETDEWEB)

    Perry, R.; Lakatos, J.; Snape, C.E.; Sun, C. [University of Nottingham, Nottingham (United Kingdom). Nottingham Fuel and Energy Centre

    2005-07-01

    To help reduce the cost of Hg capture from flue gas a number of low-cost carbons are being investigated, including activated tyre char and PFA carbon, in conjunction with some of the pre-treatments that have been found to be effective for commercial actived carbons. Experimental conditions for screening the sorbents have been selected to determine breakthrough capacities rapidly. The unactivated carbons have low breakthrough capacities under the test conditions employed (around 0.1 mg g{sup -1}) but these improve upon steam activation (around 0.25 mg g{sup -1}) but are still lower than those of non-impregnated commercial activated carbons (around 0.4-0.7 mg g{sup -1}), due to their lower surface areas. Comparable improvements to the commercial carbons have been achieved for impregnation treatments, including sulfur and bromine. However, certain gasification chars do have much higher breakthrough capacities than commercial carbons used for flue gas injection. Manganese oxide impregnation with low concentration is particularly effective for the activated and unactivated carbons giving breakthrough capacities comparable to the commercial carbons. Pointers for further increasing breakthrough and equilibrium capacities for carbon-based sorbents are discussed. 7 refs., 1 fig., 3 tabs.

  7. Hybrid Polymer/UiO-66(Zr) and Polymer/NaY Fiber Sorbents for Mercaptan Removal from Natural Gas.

    Science.gov (United States)

    Chen, Grace; Koros, William J; Jones, Christopher W

    2016-04-20

    Zeolite NaY and metal organic frameworks MIL-53(Al) and UiO-66(Zr) are spun with cellulose acetate (CA) polymer to create hybrid porous composite fibers for the selective adsorption of sulfur odorant compounds from pipeline natural gas. Odorant removal is desirable to limit corrosion associated with sulfur oxide production, thereby increasing lifetime in gas turbines used for electricity generation. In line with these goals, the performance of the hybrid fibers is evaluated on the basis of sulfur sorption capacity and selectivity, as well as fiber stability and regenerability, compared to their polymer-free sorbent counterparts. The capacities of the powder sorbents are also measured using various desorption temperatures to evaluate the potential for lower temperature, energy, and cost-efficient system operation. Both NaY/CA and UiO-66(Zr)/CA hybrid fibers are prepared with high sorbent loadings, and both have high capacities and selectivities for t-butyl mercaptan (TBM) odorant sorption from a model natural gas (NG), while being stable to multiple regeneration cycles. The different advantages and disadvantages of both types of fibers relative are discussed, with both offering the potential advantages of low pressure drop, rapid heat and mass transfer, and low energy requirements over traditional sulfur removal technologies such as hydrodesulfurization (HDS) or adsorption in a pellet packed beds. PMID:27010604

  8. Chalcogenide aerogels as sorbents for radioactive iodine

    Energy Technology Data Exchange (ETDEWEB)

    Subrahmanyam, Kota S.; Sarma, Debajit; Malliakas, Christos; Polychronopoulou, Kyriaki; Riley, Brian J.; Pierce, David A.; Chun, Jaehun; Kanatzidis, Mercouri G.

    2015-04-14

    Iodine (129I) is one of the radionuclides released in nuclear fuel reprocessing and poses risk to public safety due to its involvement in human metabolic processes. In order to prevent the leaching of hazardous radioactive iodine into the environment, its effective capture and sequestration is pivotal. In the context of finding a suitable matrix for capturing radioactive iodine the chalcogels, NiMoS4, CoMoS4, Sb4Sn4S12, Zn2Sn2S6, and CoSx (x = 4-5) were explored as iodine sorbents. All the chalcogels showed high uptake, reaching up to 225 mass% (2.25 g/g) of the final mass owing to strong chemical and physical iodine-chalcogen interactions. Analysis of the iodine-loaded specimens revealed that the iodine chemically reacted with Sb4Sn4S12, Zn2Sn2S6, and CoSx to form metal complexes SbI3, SnI4, and, KI respectively. The NiMoS4 and CoMoS4 chalcogels did not appear to undergo a chemical reaction with iodine since iodide complexes were not observed with these samples. Once heated, the iodine-loaded chalcogels released iodine in the temperature range of 75 °C to 220 °C, depending on the nature of iodine speciation. In the case of Sb4Sn4S12 and Zn2Sn2S6 iodine release was observed around 150 °C in the form of SnI4 and SbI3, respectively. The NiMoS4, CoMoS4, and CoSx released iodine at ~75 °C, which is consistent with physisorbed iodine. Preliminary investigations on consolidation of iodine-loaded Zn2Sn2S6 with Sb2S3 as a glass forming additive showed the content of iodine in consolidated glass ingots at around 25 mass%.

  9. REMOVAL OF SO2 AND NO OVER RICE HUSK ASH (RHA)/CaO-SUPPORTED METAL OXIDES

    OpenAIRE

    IRVAN DAHLAN; GUI MEEI MEI; AZLINA HARUN KAMARUDDIN; ABDUL RAHMAN MOHAMED; KEAT TEONG LEE

    2008-01-01

    The activity of rice husk ash (RHA)/CaO-based sorbent supported with various metal oxides for the removal of SO2 and NO from simulated flue gas of combustion process has been studied. In this study, RHA/CaO-based sorbents were impregnated with an appropriate metal nitrates solution followed by drying and calcinations, which resulted in the sorbent having the following active phases; MgO, MnO, CoO, ZnO, Al2O3, Fe2O3, and CeO2. The sorbent-catalysts were tested in a fixed bed reactor by passing...

  10. Acute and chronic role of nitric oxide, renin-angiotensin system and sympathetic nervous system in the modulation of calcium sensitization in Wistar Rats

    Czech Academy of Sciences Publication Activity Database

    Brunová, Aneta; Bencze, Michal; Behuliak, Michal; Zicha, Josef

    2015-01-01

    Roč. 64, č. 4 (2015), s. 447-457. ISSN 0862-8408 R&D Projects: GA ČR(CZ) GAP304/12/0259; GA MZd(CZ) NV15-25396A Institutional support: RVO:67985823 Keywords : blood pressure * kalcium sensitization * Rho kinase * nitric oxide * renin-angiotensin system * sympathetic nervous system * fasudil Subject RIV: FA - Cardiovascular Diseases incl. Cardiotharic Surgery Impact factor: 1.293, year: 2014

  11. Fluorine-fixing efficiency on calcium-based briquette: pilot experiment, demonstration and promotion

    Institute of Scientific and Technical Information of China (English)

    YANG Jiao-lan; CHEN Dong-qing; LI Shu-min; YUE Yin-ling; JIN Xin; ZHAO Bing-cheng; YING Bo

    2010-01-01

    Background The fluorosis derived from coal burning is a very serious problem in China. By using fluorine-fixing technology during coal burning we are able to reduce the release of fluorides in coal at the source in order to reduce pollution to the surrounding environment by coal burning pollutants as well as decrease the intake and accumulating amounts of fluorine in the human body. The aim of this study was to conduct a pilot experiment on calcium-based fluorine-fixing material efficiency during coal burning to demonstrate and promote the technology based on laboratory research.Methods A proper amount of calcium-based fluorine sorbent was added into high-fluorine coal to form briquettes so that the fluorine in high-fluorine coal can be fixed in coal slag and its release into atmosphere reduced. We determined figures on various components in briquettes and fluorine in coal slag as well as the concentrations of indoor air pollutants, including fluoride, sulfur dioxide and respirable particulate matter (RPM), and evaluated the fluorine-fixing efficiency of calcium-based fluorine sorbents and the levels of indoor air pollutants.Results Pilot experiments on fluorine-fixing efficiency during coal burning as well as its demonstration and promotion were carried out separately in Guiding and Longli Counties of Guizhou Province, two areas with coal burning fluorosis problems. If the calcium-based fluorine sorbent mixed coal was made into honeycomb briquettes the average fluorine-fixing ratio in the pilot experiment was 71.8%. If the burning calcium-based fluorine-fixing bitumite was made into a coalball, the average of fluorine-fixing ratio was 77.3%. The concentration of fluoride, sulfur dioxide and PM10 of indoor air were decreased significantly. There was a 10% increase in the cost of briquettes due to the addition of calcium-based fluorine sorbent.Conclusions The preparation process of calcium-based fluorine-fixing briquette is simple yet highly flammable and it is

  12. Enhancing the use of coals by gas reburning-sorbent injection: Volume 4 -- Gas reburning-sorbent injection at Lakeside Unit 7, City Water, Light and Power, Springfield, Illinois. Final report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-03-01

    A demonstration of Gas Reburning-Sorbent Injection (GR-SI) has been completed at a cyclone-fired utility boiler. The Energy and Environmental Research Corporation (EER) has designed, retrofitted and tested a GR-SI system at City Water Light and Power`s 33 MWe Lakeside Station Unit 7. The program goals of 60% NO{sub x} emissions reduction and 50% SO{sub 2} emissions reduction were exceeded over the long-term testing period; the NO{sub x} reduction averaged 63% and the SO{sub 2} reduction averaged 58%. These were achieved with an average gas heat input of 22% and a calcium (sorbent) to sulfur (coal) molar ratio of 1.8. GR-SI resulted in a reduction in thermal efficiency of approximately 1% at full load due to firing natural gas which forms more moisture in flue gas than coal and also results in a slight increase in air heater exit gas temperature. Minor impacts on other areas of unit performance were measured and are detailed in this report. The project at Lakeside was carried out in three phases, in which EER designed the GR-SI system (Phase 1), completed construction and start-up activities (Phase 2), and evaluated its performance with both short parametric tests and a long-term demonstration (Phase 3). This report contains design and technical performance data; the economics data for all sites are presented in Volume 5.

  13. Sorbent-based sampling methods for volatile and semi-volatile organic compounds in air Part 1: Sorbent-based air monitoring options.

    Science.gov (United States)

    Woolfenden, Elizabeth

    2010-04-16

    Sorbent tubes/traps are widely used in combination with gas chromatographic (GC) analytical methods to monitor the vapour-phase fraction of organic compounds in air. Target compounds range in volatility from acetylene and freons to phthalates and PCBs and include apolar, polar and reactive species. Airborne vapour concentrations will vary depending on the nature of the location, nearby pollution sources, weather conditions, etc. Levels can range from low percent concentrations in stack and vent emissions to low part per trillion (ppt) levels in ultra-clean outdoor locations. Hundreds, even thousands of different compounds may be present in any given atmosphere. GC is commonly used in combination with mass spectrometry (MS) detection especially for environmental monitoring or for screening uncharacterised workplace atmospheres. Given the complexity and variability of organic vapours in air, no one sampling approach suits every monitoring scenario. A variety of different sampling strategies and sorbent media have been developed to address specific applications. Key sorbent-based examples include: active (pumped) sampling onto tubes packed with one or more sorbents held at ambient temperature; diffusive (passive) sampling onto sorbent tubes/cartridges; on-line sampling of air/gas streams into cooled sorbent traps; and transfer of air samples from containers (canisters, Tedlar) bags, etc.) into cooled sorbent focusing traps. Whichever sampling approach is selected, subsequent analysis almost always involves either solvent extraction or thermal desorption (TD) prior to GC(/MS) analysis. The overall performance of the air monitoring method will depend heavily on appropriate selection of key sampling and analytical parameters. This comprehensive review of air monitoring using sorbent tubes/traps is divided into 2 parts. (1) Sorbent-based air sampling option. (2) Sorbent selection and other aspects of optimizing sorbent-based air monitoring methods. The paper presents

  14. Interfacial Kinetics of High-Al-Containing Ultra-Lightweight Steels with Calcium Silicate-Based Molten Oxides at High Temperature

    Science.gov (United States)

    Kim, Gi Hyun; Sohn, Il

    2016-06-01

    The kinetics of the high-temperature reaction between high-Al- and -Mn-containing steels and synthesized molten calcium silicate-based fluxes from 1623 K to 1643 K (1350 °C to 1370 °C) was studied. Cylindrical steel rods were rotated in the molten fluxes for 300 to 1200 seconds at various temperatures below the melting point of the steels. The rods were connected to a rheometer, and the initial reaction rates were estimated from the torque variations. The dissolution of the steel into the molten slag was correlated to the variation in torque. The kinetics of the reaction between the rods and the slag estimated from the torque and subsequently from the viscosity were confirmed from the mass balance and from the variation in the chemical compositions of the rods and the molten slags, respectively. The liquid-phase mass transfer coefficient of Al2O3 was calculated to be 1.14 × 10-2 cm/s at 1623 K (1350 °C) and 1.52 × 10-2 cm/s at 1633 K (1360 °C). The kinetics calculated assuming liquid-phase mass transfer control was observed to be similar to the aforementioned kinetics determined from the dynamic viscosity variations. On the basis of dimensionless analysis of the Sherwood number (Sh = 0.05·Re0.65Sc0.31), liquid-phase mass transfer from the metal/flux interface was observed to be the rate-controlling step.

  15. Modified clay sorbents for wastewater treatment and immobilization of heavy metals in soils

    Science.gov (United States)

    Burlakovs, Juris; Klavins, Maris; Vincevica-Gaile, Zane; Stapkevica, Mara

    2014-05-01

    Soil and groundwater pollution with heavy metals is the result of both, anthropogenic and natural processes in the environment. Anthropogenic influence in great extent appears from industry, mining, treatment of metal ores and waste incineration. Contamination of soil and water can be induced by diffuse sources such as applications of agrochemicals and fertilizers in agriculture, air pollution from industry and transport, and by point sources, e.g., wastewater streams, runoff from dump sites and factories. Treatment processes used for metal removal from polluted soil and water include methodologies based on chemical precipitation, ion exchange, carbon adsorption, membrane filtration, adsorption and co-precipitation. Optimal removal of heavy metal ions from aqueous medium can be achieved by adsorption process which is considered as one of the most effective methods due to its cost-effectiveness and high efficiency. Immobilization of metals in contaminated soil also can be done with different adsorbents as the in situ technology. Use of natural and modified clay can be developed as one of the solutions in immobilization of lead, zinc, copper and other elements in polluted sites. Within the present study clay samples of different geological genesis were modified with sodium and calcium chlorides, iron oxyhydroxides and ammonium dihydrogen phosphate in variable proportions of Ca/P equimolar ratio to test and compare immobilization efficiency of metals by sorption and batch leaching tests. Sorption capacity for raw clay samples was considered as relatively lower referring to the modified species of the same clay type. In addition, clay samples were tested for powder X-ray difractometry, cation exchange, surface area properties, elemental composition, as well as scanning electron microscopy pictures of clay sample surface structures were obtained. Modified clay sorbents were tested for sorption of lead as monocontaminant and for complex contamination of heavy metals. The

  16. Recent developments in novel sorbents for flue gas clean up

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yan; Bisson, Teresa M.; Yang, Hongqun; Xu, Zhenghe [Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta (Canada)

    2010-10-15

    Coal combustion is one of the most important energy sources for electricity generation, but also produces airborne pollutants. The amount of SO{sub 2} and NO{sub x} for example, is in the order of hundreds to thousands of ppm, and tens to hundreds of ppm, respectively, while Hg in flue gases could be up to tens to hundreds of ppb. Flue gas desulphurization technology is already in place for SO{sub 2} removal, and new sorbents such as zeolites are being investigated for such an application. NO{sub x} can be removed by selective catalytic reduction with various catalysts. Mercury is the hardest to remove due to its persistent nature and relatively low concentration in flue gases. New sorbents have also been developed for mercury removal applications. A current trend in flue gas emission control is to remove Hg, NO{sub x} and SO{sub 2} simultaneously. Various catalytic sorbents have been investigated to remove two or more of these pollutants concurrently. This article reviews recent developments made for emission control of coal-fired power plant flue gases using novel sorbents to target individual or multiple pollutants. (author)

  17. Evaluation of inorganic sorbent treatment for LWR coolant process streams

    International Nuclear Information System (INIS)

    This report presents results of a survey of the literature and of experience at selected nuclear installations to provide information on the feasibility of replacing organic ion exchangers with inorganic sorbents at light-water-cooled nuclear power plants. Radioactive contents of the various streams in boiling water reactors and pressurized water reactors were examined. In addition, the methods and performances of current methods used for controlling water quality at these plants were evaluated. The study also includes a brief review of the physical and chemical properties of selected inorganic sorbents. Some attributes of inorganic sorbents would be useful in processing light water reactor (LWR) streams. The inorganic resins are highly resistant to damage from ionizing radiation, and their exchange capacities are generally equivalent to those of organic ion exchangers. However, they are more limited in application, and there are problems with physical integrity, especially in acidic solutions. Research is also needed in the areas of selectivity and anion removal before inorganic sorbents can be considered as replacements for the synthetic organic resins presently used in LWRs. 11 figures, 14 tables

  18. Comments on "Ceria-Zirconia High-Temperature Desulfurization Sorbents".

    Czech Academy of Sciences Publication Activity Database

    Hartman, Miloslav; Trnka, Otakar

    2006-01-01

    Roč. 45, č. 4 (2006), s. 1548-1549. ISSN 0888-5885 Institutional research plan: CEZ:AV0Z40720504 Keywords : hydrogen sulfide * desulfurization * cerium sorbent Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 1.518, year: 2006

  19. Alkali-Doped Lithium Orthosilicate Sorbents for Carbon Dioxide Capture.

    Science.gov (United States)

    Yang, Xinwei; Liu, Wenqiang; Sun, Jian; Hu, Yingchao; Wang, Wenyu; Chen, Hongqiang; Zhang, Yang; Li, Xian; Xu, Minghou

    2016-09-01

    New alkali-doped (Na2 CO3 and K2 CO3 ) Li4 SiO4 sorbents with excellent performance at low CO2 concentrations were synthesized. We speculate that alkali doping breaks the orderly arrangement of the Li4 SiO4 crystals, hence increasing its specific surface area and the number of pores. It was shown that 10 wt % Na2 CO3 and 5 wt % K2 CO3 are the optimal additive ratios for doped sorbents to attain the highest conversions. Moreover, under 15 vol % CO2 , the doped sorbents present clearly faster absorption rates and exhibit stable cyclic durability with impressive conversions of about 90 %, at least 20 % higher than that of non-doped Li4 SiO4 . The attained conversions are also 10 % higher than the reported highest conversion of 80 % on doped Li4 SiO4 . The performance of Li4 SiO4 is believed to be enhanced by the eutectic melt, and it is the first time that the existence of eutectic Li/Na or Li/K carbonate on doped sorbents when absorbing CO2 at high temperature is confirmed; this was done using systematical analysis combining differential scanning calorimetry with in situ powder X-ray diffraction. PMID:27531239

  20. Structure and properties of carbon fiber sorbents

    International Nuclear Information System (INIS)

    Adsorption properties of fiber carbon materials, differing in initial raw material, preparation process, final treatment temperature, i. e. the factors responsible for the fiber structure, were studied. Conditions of surface activation, like oxidant nature, gas feed rate, oxidation temperature and duration were varied in a wide range of values to prepare adsorbents featuring prescribed parameters of porous structure. One type of carbon fiber was chosen and activation conditions, permitting development of the initial surface from 0.5 to 2000 m2/g without any loss of mechanical strength, were selected for it

  1. Study on the Influence of Anti-oxidants on Oxidation Stability of the Calcium Sulfonate Complex Grease by Using Pressure Differential Scanning Calorimetry%抗氧剂对复合磺酸钙基润滑脂氧化安定性的高压差示扫描量热法研究

    Institute of Scientific and Technical Information of China (English)

    谢龙; 程型国; 周圆

    2012-01-01

    利用高压差示扫描量热法(PDSC)研究了典型抗氧剂T501(2,6-二叔丁基对甲基苯酚)、L135(高分子量液体酚)、L57(辛基/戊基二苯胺)和T531(N-苯基-α萘胺)对复合磺酸钙基润滑脂氧化安定性的影响,考察了抗氧剂浓度对抗氧化效果的影响.结果表明,PDSC是一种快速简便评价润滑脂氧化安定性的方法,适用于抗氧剂的筛选.与传统的旋转氧弹氧化法相比较而言,PDSC的评价结果更科学,更具有规律性.另外,根据阿仑尼乌斯公式计算了润滑脂氧化反应的表观活化能.%Pressure differential scanning calorimetry(PDSC) was used to evaluate the effect of several anti-oxidants such as T501 (2, 6-ditert-butyl-4-methyl phenol). L135 (high molecular weight liquid phenol), L57 (octyl/amyl diphenylamine) and T531 ( N-phenyl-α-naphthylamine) on the oxidation stability of calcium sulfonate complex grease. The results showed that PDSC was a simple and rapid method for testing the oxidation of grease, and suitable for screening anti-oxidants. Compared with traditional oxygen bomb oxidation method, the evaluation result of PDSC provided a better scientific foundation and better regularity. In addition, the active energies of grease oxidation were calculated by using Arrhenius-equation.

  2. Calcium absorption and achlorhydria

    International Nuclear Information System (INIS)

    Defective absorption of calcium has been thought to exist in patients with achlorhydria. The author compared absorption of calcium in its carbonate form with that in a pH-adjusted citrate form in a group of 11 fasting patients with achlorhydria and in 9 fasting normal subjects. Fractional calcium absorption was measured by a modified double-isotope procedure with 0.25 g of calcium used as the carrier. Mean calcium absorption (+/- S.D.) in the patients with achlorhydria was 0.452 +/- 0.125 for citrate and 0.042 +/- 0.021 for carbonate (P less than 0.0001). Fractional calcium absorption in the normal subjects was 0.243 +/- 0.049 for citrate and 0.225 +/- 0.108 for carbonate (not significant). Absorption of calcium from carbonate in patients with achlorhydria was significantly lower than in the normal subjects and was lower than absorption from citrate in either group; absorption from citrate in those with achlorhydria was significantly higher than in the normal subjects, as well as higher than absorption from carbonate in either group. Administration of calcium carbonate as part of a normal breakfast resulted in completely normal absorption in the achlorhydric subjects. These results indicate that calcium absorption from carbonate is impaired in achlorhydria under fasting conditions. Since achlorhydria is common in older persons, calcium carbonate may not be the ideal dietary supplement

  3. CARBON DIOXIDE CAPTURE FROM FLUE GAS USING DRY REGENERABLE SORBENTS

    International Nuclear Information System (INIS)

    The objective of this project is to develop a simple, inexpensive process to separate CO(sub 2) as an essentially pure stream from a fossil fuel combustion system using a regenerable, sodium-based sorbent. The sorbent being used in this project is sodium carbonate which is converted to sodium bicarbonate, or ''baking soda,'' through reaction with carbon dioxide and water vapor. Sodium bicarbonate is regenerated to sodium carbonate when heated, producing a nearly pure CO(sub 2) stream after condensation of water vapor. This quarter, five cycle thermogravimetric tests were conducted at the Louisiana State University (LSU) with sodium bicarbonate Grade 3 (SBC(numbersign)3) which showed that carbonation activity declined slightly over 5 cycles following severe calcination conditions of 200 C in pure CO(sub 2). Three different sets of calcination conditions were tested. Initial carbonation activity (as measured by extent of reaction in the first 25 minutes) was greatest subsequent to calcination at 120 C in He, slightly less subsequent to calcination in 80% CO(sub 2)/20% H(sub 2)O, and lowest subsequent to calcination in pure CO(sub 2) at 200 C. Differences in the extent of reaction after 150 minutes of carbonation, subsequent to calcination under the same conditions followed the same trend but were less significant. The differences between fractional carbonation under the three calcination conditions declined with increasing cycles. A preliminary fixed bed reactor test was also conducted at LSU. Following calcination, the sorbent removed approximately 19% of the CO(sub 2) in the simulated flue gas. CO(sub 2) evolved during subsequent calcination was consistent with an extent of carbonation of approximately 49%. Following successful testing of SBC(numbersign)3 sorbent at RTI reported in the last quarter, a two cycle fluidized bed reactor test was conducted with trona as the sorbent precursor, which was calcined to sodium carbonate. In the first carbonation cycle, CO

  4. EXERCISE ENHANCING CALCIUM ABSORPTION MECHANISM

    OpenAIRE

    Muliani

    2013-01-01

    Calcium has important role in many biological processes therefore calcium homeostasis should be maintained. Imbalance in calcium homeostasis would affects the bone metabolism, neuromuscular function, blood coagulation, cell proliferation and signal transduction. Homeostasis of calcium is maintained by three major organs: gastrointestinal tract, bone and kidney. Intestinal calcium absorption is the sole mechanism to supply calcium to the body. Calcium absorption controlled by calcitropic hormo...

  5. Kinetics of deso/sub x/ reaction on copper and cerium-based sorbent-catalysts

    International Nuclear Information System (INIS)

    Kinetics of SO/sub 2/ removal using a copper-based sorbent CuO/gamma-AI/sub 2/O/sub 3/ and a cerium modified copper sorbent CuO-CeO/sub 2/gamma-AI/sub 2/O, were measured on a TGA and their kinetics behaviors were simulated with a proposed empirical rate model (ERM). The purpose of cerium addition to the copper sorbent was to study the difference of sorbent's kinetics. The cerium modified copper sorbent showed a higher reaction rate on initial sulfation than the regular copper sorbent. Both sorbents however had similar calculated activation energy. The proposed ERM model appeared to describe the SO/sub 2/ removal kinetics well in the temperature range 250-400 degree C. (author)

  6. Solid Sorbents for Removal of Carbon Dioxide from Gas Streams at Low Temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Sirwardane, Ranjani V.

    2005-06-21

    New low-cost CO2 sorbents are provided that can be used in large-scale gas-solid processes. A new method is provided for making these sorbents that involves treating substrates with an amine and/or an ether so that the amine and/or ether comprise at least 50 wt. percent of the sorbent. The sorbent acts by capturing compounds contained in gaseous fluids via chemisorption and/or physisorption between the unit layers of the substrate's lattice where the polar amine liquids and solids and/or polar ether liquids and solids are located. The method eliminates the need for high surface area supports and polymeric materials for the preparation of CO2 capture systems, and provides sorbents with absorption capabilities that are independent of the sorbents' surface areas. The sorbents can be regenerated by heating at temperatures in excess of 35 degrees C.

  7. Sorbents for Phenol Removal from Contaminated Waters

    OpenAIRE

    Papežová, Barbora

    2014-01-01

    Nowadays, contamination of underground and surface water by various pollutants is serious environmental problem. Phenol and phenolic compounds belong to the most common organic pollutants. Huge sources of contamination are industrial waste waters (from chemical, rubber, pharmaceutical, petrochemical and other industry), which are necessary to purify. Various techniques (oxidation, enzymatic purification, sorption, photocatalysis, or their combination) are used for water treatment. This study ...

  8. Localization of Nitric Oxide Synthase-containing Neurons in the Bat Visual Cortex and Co-localization with Calcium-binding Proteins

    International Nuclear Information System (INIS)

    Microchiroptera (microbats) is a suborder of bats thought to have degenerated vision. However, many recent studies have shown that they have visual ability. In this study, we labeled neuronal nitric oxide synthase (nNOS)—the synthesizing enzyme of the gaseous non-synaptic neurotransmitter nitric oxide—and co-localized it with calbindin D28K (CB), calretinin (CR), and parvalbumin (PV) in the visual cortex of the greater horseshoe bat (Rhinolophus ferrumequinum, a species of microbats). nNOS-immunoreactive (IR) neurons were found in all layers of the visual cortex. Intensely labeled neurons were most common in layer IV, and weakly labeled neurons were most common in layer VI. Majority of the nNOS-IR neurons were round- or oval-type neurons; no pyramidal-type neurons were found. None of these neurons co-localized with CB, CR, or PV. However, the synthesis of nitric oxide in the bat visual cortex by nNOS does not depend on CB, CR, or PV

  9. A study on the carbon-based sorbents injection for gas phase mercury removal from flue gas

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S.; Rhim, Y.; Kim, S.; Park, Y. (and others) [Korea Institute of Energy Research, Daejoen (Republic of Korea). Clean Energy Research Department

    2003-07-01

    To develop carbon-based sorbents to be used in gas-phase mercury removal, the performance of virgin activated carbons (AC) and that of chemically treated activated carbons were compared. Virgin activated carbons (ACs) were made of bituminous coal, lignite, anthracite and NSH4X10. Chemical treated ACs used were those impregnated with sulphuric acid, nitric acid, 1% sulfur, and with mixed sulphuric and nitric acid. Pre-oxidation of activated carbons with acids was also investigated and adsorption performances were compared. Injection of activated carbons has been investigated and the influential factors such as temperature, carbon dose were also discussed. 5 refs., 4 figs., 2 tabs.

  10. Recovery of Cerium Dioxide from Spent Glass-Polishing Slurry and Its Utilization as a Reactive Sorbent for Fast Degradation of Toxic Organophosphates

    OpenAIRE

    Pavel Janoš; Pavel Kuráň; Jakub Ederer; Martin Šťastný; Luboš Vrtoch; Martin Pšenička; Jiří Henych; Karel Mazanec; Miroslav Skoumal

    2015-01-01

    The recovery of cerium (and possibly other rare earth elements) from the spent glass-polishing slurries is rather difficult because of a high resistance of polishing-grade cerium oxide toward common digestion agents. It was shown that cerium may be extracted from the spent polishing slurries by leaching with strong mineral acids in the presence of reducing agents; the solution may be used directly for the preparation of a ceria-based reactive sorbent. A mixture of concentrated nitric acid and...

  11. Lime-Based Sorbents for High-Temperature CO2 Capture—A Review of Sorbent Modification Methods

    Directory of Open Access Journals (Sweden)

    Edward J. Anthony

    2010-08-01

    Full Text Available This paper presents a review of the research on CO2 capture by lime-based looping cycles undertaken at CanmetENERGY’s (Ottawa, Canada research laboratories. This is a new and very promising technology that may help in mitigation of global warming and climate change caused primarily by the use of fossil fuels. The intensity of the anticipated changes urgently requires solutions such as more cost-effective technologies for CO2 capture. This new technology is based on the use of lime-based sorbents in a dual fluidized bed combustion (FBC reactor which contains a carbonator—a unit for CO2 capture, and a calciner—a unit for CaO regeneration. However, even though natural materials are cheap and abundant and very good candidates as solid CO2 carriers, their performance in a practical system still shows significant limitations. These limitations include rapid loss of activity during the capture cycles, which is a result of sintering, attrition, and consequent elutriation from FBC reactors. Therefore, research on sorbent performance is critical and this paper reviews some of the promising ways to overcome these shortcomings. It is shown that reactivation by steam/water, thermal pre-treatment, and doping simultaneously with sorbent reforming and pelletization are promising potential solutions to reduce the loss of activity of these sorbents over multiple cycles of use.

  12. Opening of small and intermediate calcium-activated potassium channels induces relaxation mainly mediated by nitric-oxide release in large arteries and endothelium-derived hyperpolarizing factor in small arteries from rat

    DEFF Research Database (Denmark)

    Stankevicius, Edgaras; Dalsgaard, Thomas; Kroigaard, Christel;

    2011-01-01

    current, and NO release that were blocked by apamin and TRAM-34 or charybdotoxin. These findings suggest that opening of SK(Ca) and IK(Ca) channels leads to endothelium-dependent relaxation that is mediated mainly by NO in large mesenteric arteries and by EDHF-type relaxation in small mesenteric arteries......This study was designed to investigate whether calcium-activated potassium channels of small (SK(Ca) or K(Ca)2) and intermediate (IK(Ca) or K(Ca)3.1) conductance activated by 6,7-dichloro-1H-indole-2,3-dione 3-oxime (NS309) are involved in both nitric oxide (NO) and endothelium......-derived hyperpolarizing factor (EDHF)-type relaxation in large and small rat mesenteric arteries. Segments of rat superior and small mesenteric arteries were mounted in myographs for functional studies. NO was recorded using NO microsensors. SK(Ca) and IK(Ca) channel currents and mRNA expression were investigated in...

  13. Magnetically separable reactive sorbent based on the CeO2/γ-Fe2O3 composite and its utilization for rapid degradation of the organophosphate pesticide parathion methyl and certain nerve agents

    Czech Academy of Sciences Publication Activity Database

    Janoš, P.; Kuráň, P.; Pilařová, V.; Trögl, J.; Šťastný, M.; Pelant, O.; Henych, Jiří; Bakardjieva, Snejana; Životský, O.; Kormunda, M.; Mazanec, K.; Skoumal, M.

    2015-01-01

    Roč. 262, FEB (2015), s. 747-755. ISSN 1385-8947 R&D Projects: GA ČR(CZ) GAP106/12/1116 Institutional support: RVO:61388980 Keywords : Magnetically separable sorbent * Destructive sorption * Cerium oxide * Parathion methyl * Toxic organophosphates Subject RIV: CA - Inorganic Chemistry Impact factor: 4.321, year: 2014

  14. Synthesis of iron-based chemical looping sorbents integrated with pH swing carbon mineral sequestration.

    Science.gov (United States)

    Kim, Hyung Ray; Lee, Dong Hyun; Fan, Liang-Shih; Park, Ah-Hyung Alissa

    2009-12-01

    The previously developed pH swing carbon mineral sequestration immobilizes the gaseous CO2 into a thermodynamically stable solid, MgCO3, using Mg-bearing minerals such as serpentine. This mineral carbonation technology is particularly promising since it generates value-added solid products: high surface area silica, iron oxide, and magnesium carbonate, while providing a safe and permanent storage option for CO2. By carefully controlling the pH of the system, these solids products can be produced with high purity. This study focuses on the synthesis of iron oxide particles as a chemical looping sorbent in order to achieve the integration between carbon capture and storage technologies. Since the solubility of Fe in aqueous phase is relatively low at neutral pH, the effect of the weak acid and chelating agents on the extraction of Fe from serpentine was investigated. The synthesized iron-based chemical looping sorbent was found to be as effective as commercially available iron oxide nanoparticles at converting syngas into high purity H2, while producing a sequestration-ready CO2 stream. PMID:19908801

  15. Dengue and Calcium

    OpenAIRE

    Shivanthan, Mitrakrishnan C; Rajapakse, Senaka

    2014-01-01

    Dengue is potentially fatal unless managed appropriately. No specific treatment is available and the mainstay of treatment is fluid management with careful monitoring, organ support, and correction of metabolic derangement. Evidence with regards to the role of calcium homeostasis in dengue is limited. Low blood calcium levels have been demonstrated in dengue infection and hypocalcemia maybe more pronounced in more severe forms. The cause of hypocalcemia is likely to be multifactorial. Calcium...

  16. Measurements of intracellular calcium

    International Nuclear Information System (INIS)

    Intracellular calcium concentration ([Ca2+]i) has been measured in cultured cells by using Fura-2 load cells and a computer-controlled Perkin Elmer LS-5B spectrofluorometer. Increased [Ca2+]i in cells exposed to extracellular bilirubin was observed both with and without extracellular calcium. However, the increase was considerable larger with extracellular calcium. The enhancement of [Ca2+]i became smaller with decreasing bilirubin/BSA (bovine serum albumine) ratio. 5 refs., 5 figs

  17. Calcium-dependent nitric oxide production is involved in the cytoprotective properties of n-acetylcysteine in glycochenodeoxycholic acid-induced cell death in hepatocytes

    International Nuclear Information System (INIS)

    The intracellular oxidative stress has been involved in bile acid-induced cell death in hepatocytes. Nitric oxide (NO) exerts cytoprotective properties in glycochenodeoxycholic acid (GCDCA)-treated hepatocytes. The study evaluated the involvement of Ca2+ on the regulation of NO synthase (NOS)-3 expression during N-acetylcysteine (NAC) cytoprotection against GCDCA-induced cell death in hepatocytes. The regulation of Ca2+ pools (EGTA or BAPTA-AM) and NO (L-NAME or NO donor) production was assessed during NAC cytoprotection in GCDCA-treated HepG2 cells. The stimulation of Ca2+ entrance was induced by A23187 in HepG2. Cell death, Ca2+ mobilization, NOS-1, -2 and -3 expression, AP-1 activation, and NO production were evaluated. GCDCA reduced intracellular Ca2+ concentration and NOS-3 expression, and enhanced cell death in HepG2. NO donor prevented, and L-NAME enhanced, GCDCA-induced cell death. The reduction of Ca2+ entry by EGTA, but not its release from intracellular stores by BAPTA-AM, enhanced cell death in GCDCA-treated cells. The stimulation of Ca2+ entrance by A23187 reduced cell death and enhanced NOS-3 expression in GCDCA-treated HepG2 cells. The cytoprotective properties of NAC were related to the recovery of intracellular Ca2+ concentration, NOS-3 expression and NO production induced by GCDCA-treated HepG2 cells. The increase of NO production by Ca2+-dependent NOS-3 expression during NAC administration reduces cell death in GCDCA-treated hepatocytes.

  18. Sorbent utilization studies using a mini-pilot spray dryer. Final report, August 1, 1991--August 31, 1992

    Energy Technology Data Exchange (ETDEWEB)

    Keener, T.C.; Khang, S.J.; Wang, J. [Cincinnati Univ., OH (United States)

    1992-10-01

    This report stems from a program supported by the Ohio Coal Development Office, that is part of a multi-task, multi-university effort concerned with developing and enhancing the efficiency of ``dry`` high-sulfur flue gas scrubbing processes using calcium based sorbents. The application of spray-drying flue gas desulfurization (FGD) to sources burning Ohio coal will depend on many factors, two of which are process simplicity and flexibility, and overall cost. The ability of the system to be able to handle variations in volumetric flow SO{sub 2} concentration, and even perhaps, new regulatory requirements imposed in the future are very important In addition, the amount and characteristics of the waste produced will be a major component in the operating costs of these systems. Spray-drying FGD has been shown to have a capital, cost advantage over conventional wet scrubbing, and the method has been proven to be comparatively simple and flexible. The major disadvantage is the inability of these systems to obtain high (> 90%) S0{sub 2} removal efficiencies on flue gas from high sulfur coal sources. This is the result of chemical mass transfer and thermal limitations imposed on these systems using calcium hydroxide in a slurry as the scrubbing agent. The project 1.5 has investigated a number of novel methods to improve the performance of these systems in a mini-pilot plant spray dryer facility. The objectives of project 1.5 were the following: Perform baseline parametric testing, study the effect of additives on reactivity, and perform sorbent recycle tests.

  19. Bioactivity studies of calcium magnesium silicate prepared from eggshell waste by sol–gel combustion synthesis

    OpenAIRE

    Rajan Choudhary; Sivasankar Koppala; Sasikumar Swamiappan

    2015-01-01

    The present study focused on the synthesis of calcium magnesium silicate (akermanite, Ca2MgSi2O7) using eggshell biowaste (as calcium source), magnesium nitrate and tetraethyl orthosilicate (TEOS) as starting materials. Sol–gel combustion method was adopted to obtain calcium magnesium silicate. Citric acid was used as a fuel (reducing agent) and nitrate ions present in the metal nitrates acts as an oxidizing agent during combustion process. The characterization of synthesized calcium magnesiu...

  20. Carbon Dioxide Capture from Flue Gas Using Dry Regenerable Sorbents

    Energy Technology Data Exchange (ETDEWEB)

    Thomas Nelson; David Green; Paul Box; Raghubir Gupta; Gennar Henningsen

    2007-06-30

    Regenerable sorbents based on sodium carbonate (Na{sub 2}CO{sub 3}) can be used to separate carbon dioxide (CO{sub 2}) from coal-fired power plant flue gas. Upon thermal regeneration and condensation of water vapor, CO{sub 2} is released in a concentrated form that is suitable for reuse or sequestration. During the research project described in this report, the technical feasibility and economic viability of a thermal-swing CO{sub 2} separation process based on dry, regenerable, carbonate sorbents was confirmed. This process was designated as RTI's Dry Carbonate Process. RTI tested the Dry Carbonate Process through various research phases including thermogravimetric analysis (TGA); bench-scale fixed-bed, bench-scale fluidized-bed, bench-scale co-current downflow reactor testing; pilot-scale entrained-bed testing; and bench-scale demonstration testing with actual coal-fired flue gas. All phases of testing showed the feasibility of the process to capture greater than 90% of the CO{sub 2} present in coal-fired flue gas. Attrition-resistant sorbents were developed, and these sorbents were found to retain their CO{sub 2} removal activity through multiple cycles of adsorption and regeneration. The sodium carbonate-based sorbents developed by RTI react with CO{sub 2} and water vapor at temperatures below 80 C to form sodium bicarbonate (NaHCO3) and/or Wegscheider's salt. This reaction is reversed at temperatures greater than 120 C to release an equimolar mixture of CO{sub 2} and water vapor. After condensation of the water, a pure CO{sub 2} stream can be obtained. TGA testing showed that the Na{sub 2}CO3 sorbents react irreversibly with sulfur dioxide (SO{sub 2}) and hydrogen chloride (HCl) (at the operating conditions for this process). Trace levels of these contaminants are expected to be present in desulfurized flue gas. The sorbents did not collect detectable quantities of mercury (Hg). A process was designed for the Na{sub 2}CO{sub 3}-based sorbent that

  1. Key factor in rice husk ash/CaO sorbent for high flue gas desulfurization activity

    Energy Technology Data Exchange (ETDEWEB)

    Irvan Dahlan; Keat Teong Lee; Azlina Harun Kamaruddin; Abdul Rahman Mohamed [Universiti Sains Malaysia, Nibong Tebal (Malaysia). School of Chemical Engineering

    2006-10-01

    Siliceous materials such as rice husk ash (RHA) have potential to be utilized as high performance sorbents for the flue gas desulfurization process in small-scale industrial boilers. This study presents findings on identifying the key factor for high desulfurization activity in sorbents prepared from RHA. Initially, a systematic approach using central composite rotatable design was used to develop a mathematical model that correlates the sorbent preparation variables to the desulfurization activity of the sorbent. The sorbent preparation variables studied are hydration period, x{sub 1} (6-16 h), amount of RHA, x{sub 2} (5-15 g), amount of CaO, x{sub 3} (2-6 g), amount of water, x{sub 4} (90-110 mL), and hydration temperature, x{sub 5} (150-250{sup o}C). The mathematical model developed was subjected to statistical tests and the model is adequate for predicting the SO{sub 2} desulfurization activity of the sorbent within the range of the sorbent preparation variables studied. Based on the model, the amount of RHA, amount of CaO, and hydration period used in the preparation step significantly influenced the desulfurization activity of the sorbent. The ratio of RHA and CaO used in the preparation mixture was also a significant factor that influenced the desulfurization activity of the sorbent. A RHA to CaO ratio of 2.5 leads to the formation of specific reactive species in the sorbent that are believed to be the key factor responsible for high desulfurization activity in the sorbent. Other physical properties of the sorbent such as pore size distribution and surface morphology were found to have insignificant influence on the desulfurization activity of the sorbent. 31 refs., 5 figs., 3 tabs.

  2. Characterization of gas reburning-sorbent injection technology by-products

    International Nuclear Information System (INIS)

    This paper reports that three samples of fly ashes from pilot-scale tests of gas reburning and sorbent injection (GR-SI) technology were characterized physically, chemically, and mineralogically. Texturally, the samples consist of approximately 97% of the total mass of the sample on average. Approximately 3% of the sample mass consisted of the elements Cl, Mg, P, K, Na, and Ti, and ).4% consisted of trace elements. Major crystalline compounds found in these samples were lime (CaO), anhydrite (CaSO4), and calcium carbonate (CaCO3). The morphology and chemistry of particles in GR-SI samples were similar to those of particles in conventional coal fly ashes. Most of the particles were calcerous. Silicate and alumino-silicate particles were fewer in number, and iron-rich particles were rare. The EP test indicated that extract concentrations of Ag, As, Ba, Cd, Cr, Pb, and Se were sell below the EPA regulatory levels. Predictions of leachate compositions from these types of fly ashes, if disposed of as a landfill at a midwestern U.S. site indicate, that during the first ten years the concentrations of Ca, SO4, Na, b, and OH would remain high. The concentrations of minor constituents (As, Ba, Cd, Cd, cu, Cr, Fe, Ni, and Se) in the leachate are predicted to be at trace levels

  3. Calcium D-saccharate

    DEFF Research Database (Denmark)

    Garcia, André Castilho; Hedegaard, Martina Vavrusova; Skibsted, Leif Horsfelt

    2016-01-01

    Molar conductivity of saturated aqueous solutions of calcium d-saccharate, used as a stabilizer of beverages fortified with calcium d-gluconate, increases strongly upon dilution, indicating complex formation between calcium and d-saccharate ions, for which, at 25 °C, Kassoc = 1032 ± 80, ΔHassoc......° = -34 ± 6 kJ mol-1, and ΔSassoc° = -55 ± 9 J mol-1 K-1, were determined electrochemically. Calcium d-saccharate is sparingly soluble, with a solubility product, Ksp, of (6.17 ± 0.32) × 10-7 at 25 °C, only moderately increasing with the temperature: ΔHsol° = 48 ± 2 kJ mol-1, and ΔSassoc° = 42 ± 7 J mol-1...... K-1. Equilibria in supersaturated solutions of calcium d-saccharate seem only to adjust slowly, as seen from calcium activity measurements in calcium d-saccharate solutions made supersaturated by cooling. Solutions formed by isothermal dissolution of calcium d-gluconate in aqueous potassium d...

  4. Synthesis and investigation of sorbing materials based on natural and synthetic dispersed oxide systems for sorbing active leaching products of lava-like fuel-containing materials

    International Nuclear Information System (INIS)

    Laboratory sorbent samples were synthesized on the basis of modified natural clayey raw material and fumed silica. Using chemical methods, composition of synthesized sorbents was established. Oxide and hydroxide structures, plated on the fumed silica and natural montmorillonite clay surface were identified. A forecast about sorbing properties of synthesized materials is made

  5. Serum Calcium Level in Hypertension

    OpenAIRE

    Hazari, Mohammed Abdul Hannan; Arifuddin, Mehnaaz Sameera; Muzzakar, Syed; Reddy, Vontela Devender

    2012-01-01

    Background: The alterations in extracellular calcium level may influence intracellular calcium level and possibly play a role in the pathogenesis of essential hypertension. Aim: The purpose was to find out the association between serum calcium levels and hypertension; and to compare the serum calcium levels between normotensive controls, hypertensive subjects on calcium channel blockers, and hypertensive subjects on antihypertensive medication other than calcium channel blockers. Materials an...

  6. Hydrogen sulfide removal from hot coal gas by various mesoporous silica supported Mn{sub 2}O{sub 3} sorbents

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Z.F.; Liu, B.S., E-mail: bingsiliu@tju.edu.cn; Wang, F.; Wang, W.S.; Xia, C.; Zheng, S.; Amin, R.

    2014-09-15

    Graphical abstract: - Highlights: • Mn{sub 2}O{sub 3}/KIT-1 presented the best desulfurization performance at 600–850 °C. • High sulfur capacity of Mn{sub 2}O{sub 3}/KIT-1 correlated closely with 3-D channel of KIT-1. • Desulfurization character depended strongly on framework structure of sorbents. • High steam content suppressed greatly the occurrence of sulfidation reaction. - Abstract: A series of 50 wt% Mn{sub 2}O{sub 3} sorbents was prepared using various mesoporous silica, MCM-41, HMS, and KIT-1 as support. The influence of textural parameters of mesoporous silica, especially type of channel on the desulfurization performance of Mn{sub 2}O{sub 3} sorbents was investigated at 600–850 °C using hot coal gas containing 0.33 vol.% H{sub 2}S. The fresh and used sorbents were characterized by means of N{sub 2}-adsorption, x-ray diffraction (XRD), high resolution transmission microscopy (HRTEM) and H{sub 2} temperature- programmed reduction (H{sub 2}-TPR) techniques. The results confirmed that the manganese oxide was dispersed highly in regular pore channel of the mesoporous supports due to high surface area. Compared with the Mn{sub 2}O{sub 3}/diatomite, all mesoporous silica supported Mn{sub 2}O{sub 3} sorbents exhibited high breakthrough sulfur capacity and a sharp deactivation rate after the breakthrough point. Compared to Mn{sub 2}O{sub 3}/MCM-41 and Mn{sub 2}O{sub 3}/HMS sorbent, the Mn{sub 2}O{sub 3}/KIT-1 showed better desulfurization performance because of the 3D wormhole-like channel. The high sulfur capacity of the Mn{sub 2}O{sub 3}/KIT-1 sorbent was maintained during the eight consecutive desulfurization-regeneration cycles. The Mn{sub 2}O{sub 3}/KIT-1 still presented high desulfurization activity when hot coal gas contained low steam (<5%)

  7. 氧化锌丁香油和氢氧化钙碘仿糊剂在乳牙根管充填中的疗效观察%Comparative study on zinc oxide eugenol and calcium hydroxide iodoform pastes as obturation materials for primary teeth

    Institute of Scientific and Technical Information of China (English)

    万惠; 符方满; 庞红霞; 符起亚

    2013-01-01

    目的 评估氧化锌丁香油和氢氧化钙碘仿糊剂作为乳牙根管充填材料的治疗效果.方法 将54颗下颌乳磨牙随机分为两组,其中27 颗接受氧化锌丁香油糊剂根管充填,27 颗接受氢氧化钙碘仿糊剂根管充填.在治疗后6 个月时用临床和影像指标评估治疗效果.结果 氧化锌丁香油和氢氧化钙碘仿糊剂根管充填后在临床和愈合指标方面差异无统计学意义(P>0.05),但超充后的氢氧化钙碘仿糊剂似乎比超充的氧化锌丁香油糊剂更容易吸收.结论 氧化锌丁香油和氢氧化钙碘仿糊剂在促进根尖愈合方面均为较好的根管充填材料,但若考虑到超充后材料的吸收,后者似乎更安全一些.%Objective To evaluate zinc oxide eugenol and calcium hydroxide iodoform as root canal obturation materials for primary teeth. Methods The canals of twenty-seven primary mandibular molars were obturated with zinc oxide eugenol and those of the other twenty-seven were obturated with calcium hydroxide iodoform. A set of clinical and radiological criteria was used to evaluate treatment outcomes at the completion of treatment and six months after treatment. Results No difference in terms of success rate 6 months after treatment was found between canals obturated with zinc oxide eugenol and those obturated with calcium hydroxide iodoform. In cases of overfill, calcium hydroxide iodoform seemed to be absorbed than zinc oxide eugenol. Conclusion Both zinc oxide eugenol and calcium hydroxide iodoform are good obturating materials. However, the latter may be a better choice where overfills are concerned.

  8. Synthesis, Characterization and Selectivity of some Radionuclides on EGIB Sorbent

    International Nuclear Information System (INIS)

    Polyacrylamide cerium titnate (EGIB) sorbent is a new composite ion exchanger was prepared via sol-gel mixing of organic polymer polyacrylamide into the matrices of the inorganic precipitate of Ce (IV) titanate. The material was characterized by X-ray diffraction, infrared, XRF, surface area, DTA and TGA. The effect of gamma irradiation has been evaluated by measuring the capacities for Cs+, Co2+ and Eu3+ ions in batch experiments. The results showed that the material has high radiation stability on expose to doses up to 50 kGy. There was no significant change in color, infrared spectra, XRD, DTA and TGA of the sorbent upon irradiation. The effect of drying temperatures was also studied for sorption of Cs+ ions on the prepared material

  9. Red muds are a new kind of sorbent for strontium

    International Nuclear Information System (INIS)

    Red mud is a kind of alumina production, characterized by high content of fine-dispersion Fe, Al and Ti oxyhydrates; it is studied from the viewpoint of its application as a sorbent for Sr. The red mud specific surface constitutes 23-25 m2/g, the density is of 3.3-3.4 g/cm3 and the melting temperature is 1350-1370 deg C. It is established that the maximum sorption capacity of the red mud for strontium equals 420 ± 24 mg-eq/100 g. The red mud high sorption properties make it possible to recommend it as a sorbent by constructing technogenic barriers at the radioactive wastes disposal sites

  10. CARBON DIOXIDE CAPTURE FROM FLUE GAS USING DRY REGENERABLE SORBENTS

    Energy Technology Data Exchange (ETDEWEB)

    David A. Green; Brian S. Turk; Raghubir Gupta; Alejandro Lopez-Ortiz

    2001-01-01

    Four grades of sodium bicarbonate and two grades of trona were characterized in terms of particle size distribution, surface area, pore size distribution, and attrition. Surface area and pore size distribution determinations were conducted after calcination of the materials. The sorbent materials were subjected to thermogravimetric testing to determine comparative rates and extent of calcination (in inert gas) and sorption (in a simulated coal combustion flue gas mixture). Selected materials were exposed to five calcination/sorption cycles and showed no decrease in either sorption capacity or sorption rate. Process simulations were conducted involving different heat recovery schemes. The process is thermodynamically feasible. The sodium-based materials appear to have suitable physical properties for use as regenerable sorbents and, based on thermogravimetric testing, are likely to have sorption and calcination rates that are rapid enough to be of interest in full-scale carbon sequestration processes.

  11. Polymer sorbent with the properties of an artificial cholesterol receptor

    Science.gov (United States)

    Polyakova, I. V.; Ezhova, N. M.; Osipenko, A. A.; Pisarev, O. A.

    2015-02-01

    A cholesterol-imprinted polymer sorbent and the corresponding reticular control copolymer were synthesized from hydroxyethyl methacrylate and ethyleneglycol dimethacrylate. The sorption isotherms of cholesterol were analyzed using the generalized Langmuir and Freundlich equations. In the case of the imprinted reticular polymer, cholesterol sorption occurred on the energetically homogeneous binding centers, forming one monolayer, while the nonspecific sorption of cholesterol on the control copolymer occurred with energetically nonhomogeneous binding of the sorbate and depended on the physicochemical conditions of sorption.

  12. Pilot plant tests of Z-Sorb{trademark} sorbent

    Energy Technology Data Exchange (ETDEWEB)

    Greenwood, G.J.; Khare, G.P.; Kubicek, D.H.; Delzer, G.A.; Kinsinger, D.L.

    1995-06-01

    The objective of this work is to determine the long-term chemical reactivity and mechanical durability of Phillips Petroleum Company`s (PPCo`s) proprietary Z-Sorb{trademark} sorbent. Materials developed for fixed-, moving- and fluid bed desulfurization of coal derived gases at high pressure (5-20 atm) and moderate operating temperatures (600-1000{degrees}F) will be discussed.

  13. CARBON DIOXIDE CAPTURE FROM FLUE GAS USING DRY REGENERABLE SORBENTS

    Energy Technology Data Exchange (ETDEWEB)

    David A. Green; Brian S. Turk; Raghubir P. Gupta; William J. McMichael; Douglas P. Harrison; Ya Liang

    2002-04-01

    The objective of this project is to develop a simple, inexpensive process to separate CO{sub 2} as an essentially pure stream from a fossil fuel combustion system using a regenerable, sodium-based sorbent. The sorbents being investigated in this project are primarily alkali carbonates, and particularly sodium carbonate and potassium carbonate, which are converted to bicarbonates, through reaction with carbon dioxide and water vapor. Bicarbonates are regenerated to carbonates when heated, producing a nearly pure CO{sub 2} stream after condensation of water vapor. This quarter, electrobalance tests conducted at LSU indicated that exposure of sorbent to water vapor prior to contact with carbonation gas does not significantly increase the reaction rate. Calcined fine mesh trona has a greater initial carbonation rate than calcined sodium bicarbonate, but appears to be more susceptible to loss of reactivity under severe calcination conditions. The Davison attrition indices for Grade 5 sodium bicarbonate, commercial grade sodium carbonate and extra fine granular potassium carbonate were, as tested, outside of the range suitable for entrained bed reactor testing. Fluidized bed testing at RTI indicated that in the initial stages of reaction potassium carbonate removed 35% of the carbon dioxide in simulated flue gas, and is reactive at higher temperatures than sodium carbonate. Removals declined to 6% when 54% of the capacity of the sorbent was exhausted. Carbonation data from electrobalance testing was correlated using a shrinking core reaction model. The activation energy of the reaction of sodium carbonate with carbon dioxide and water vapor was determined from nonisothermal thermogravimetry.

  14. Calcium controls the assembly of the photosynthetic water-oxidizing complex: a cadmium(II) inorganic mutant of the Mn4Ca core.

    Science.gov (United States)

    Bartlett, John E; Baranov, Sergei V; Ananyev, Gennady M; Dismukes, G Charles

    2008-03-27

    Perturbation of the catalytic inorganic core (Mn4Ca1OxCly) of the photosystem II-water-oxidizing complex (PSII-WOC) isolated from spinach is examined by substitution of Ca2+ with cadmium(II) during core assembly. Cd2+ inhibits the yield of reconstitution of O2-evolution activity, called photoactivation, starting from the free inorganic cofactors and the cofactor-depleted apo-WOC-PSII complex. Ca2+ affinity increases following photooxidation of the first Mn2+ to Mn3+ bound to the 'high-affinity' site. Ca2+ binding occurs in the dark and is the slowest overall step of photoactivation (IM1-->IM1* step). Cd2+ competitively blocks the binding of Ca2+ to its functional site with 10- to 30-fold higher affinity, but does not influence the binding of Mn2+ to its high-affinity site. By contrast, even 10-fold higher concentrations of Cd2+ have no effect on O2-evolution activity in intact PSII-WOC. Paradoxically, Cd2+ both inhibits photoactivation yield, while accelerating the rate of photoassembly of active centres 10-fold relative to Ca2+. Cd2+ increases the kinetic stability of the photooxidized Mn3+ assembly intermediate(s) by twofold (mean lifetime for dark decay). The rate data provide evidence that Cd2+ binding following photooxidation of the first Mn3+, IM1-->IM1*, causes three outcomes: (i) a longer intermediate lifetime that slows IM1 decay to IM0 by charge recombination, (ii) 10-fold higher probability of attaining the degrees of freedom (either or both cofactor and protein d.f.) needed to bind and photooxidize the remaining 3 Mn2+ that form the functional cluster, and (iii) increased lability of Cd2+ following Mn4 cluster assembly results in (re)exchange of Cd2+ by Ca2+ which restores active O2-evolving centres. Prior EPR spectroscopic data provide evidence for an oxo-bridged assembly intermediate, Mn3+(mu-O2(-))Ca2+, for IM1*. We postulate an analogous inhibited intermediate with Cd2+ replacing Ca2+. PMID:17954439

  15. Exogenous hydrogen peroxide, nitric oxide and calcium mediate root ion fluxes in two non-secretor mangrove species subjected to NaCl stress.

    Science.gov (United States)

    Lu, Yanjun; Li, Niya; Sun, Jian; Hou, Peichen; Jing, Xiaoshu; Zhu, Huipeng; Deng, Shurong; Han, Yansha; Huang, Xuxin; Ma, Xujun; Zhao, Nan; Zhang, Yuhong; Shen, Xin; Chen, Shaoliang

    2013-01-01

    Using 3-month-old seedlings of Bruguiera gymnorrhiza (L.) Savigny and Kandelia candel (L.) Druce, we compared species differences in ionic homeostasis control between the two non-secretor mangrove species. A high salinity (400 mM NaCl, 4 weeks) resulted in a decline of the K(+)/Na(+) ratio in root and leaf tissues, and the reduction was more pronounced in K. candel (41-66%) as compared with B. gymnorrhiza (5-36%). Salt-altered flux profiles of Na(+), K(+), H(+) and Ca(2+) in roots and effects of exogenous hydrogen peroxide (H(2)O(2)), nitric oxide (NO) and Ca(2+) on root ion fluxes were examined in seedlings that were hydroponically treated short term with 100 mM NaCl (ST, 24 h) and long term with 200 mM NaCl (LT, 7 days). Short term and LT salinity resulted in Na(+) efflux and a correspondingly increased H(+) influx in roots of both species, although a more pronounced effect was observed in B. gymnorrhiza. The salt-enhanced exchange of Na(+) with H(+) was obviously inhibited by amiloride (a Na(+)/H(+) antiporter inhibitor) or sodium orthovanadate (a plasma membrane H(+)-ATPase inhibitor), indicating that the Na(+) efflux resulted from active Na(+) exclusion across the plasma membrane. Short term and LT salinity accelerated K(+) efflux in the two species, but K. candel exhibited a higher flux rate. The salt-induced K(+) efflux was markedly restricted by the K(+) channel blocker, tetraethylammonium chloride, indicating that the K(+) efflux is mediated by depolarization-activated channels, e.g., KORCs (outward rectifying K(+) channels) and NSCCs (non-selective cation channels). Exogenous H(2)O(2) application (10 mM) markedly increased the apparent Na(+) efflux and limited K(+) efflux in ST-treated roots, although H(2)O(2) caused a higher Na(+) efflux in B. gymnorrhiza roots. CaCl(2) (10 mM) reduced the efflux of K(+) in salinized roots of the two mangroves, but its enhancement of Na(+) efflux was found only in B. gymnorrhiza. Under ST treatment, sodium nitroprusside

  16. CARBON DIOXIDE CAPTURE FROM FLUE GAS USING DRY REGENERABLE SORBENTS

    Energy Technology Data Exchange (ETDEWEB)

    David A. Green; Brian S. Turk; Raghubir P. Gupta; Alejandro Lopez-Ortiz; Douglas P. Harrison; Ya Liang

    2001-07-01

    Sodium based sorbents including sodium carbonate may be used to capture carbon dioxide from flue gas. A relatively concentrated carbon dioxide stream may be recoverable for sequestration when the sorbent is regenerated. Electrobalance tests indicated that sodium carbonate monohydrate was formed in a mixture of helium and water vapor at temperatures below 65 C. Additional compounds may also form, but this could not be confirmed. In the presence of carbon dioxide and water vapor, both the initial reaction rate of sodium carbonate with carbon dioxide and water and the sorbent capacity decreased with increasing temperature, consistent with the results from the previous quarter. Increasing the carbon dioxide concentration at constant temperature and water vapor concentration produced a measurable increase in rate, as did increasing the water vapor concentration at constant carbon dioxide concentration and temperature. Runs conducted with a flatter TGA pan resulted in a higher initial reaction rate, presumably due to improved gas-solid contact, but after a short time, there was no significant difference in the rates measured with the different pans. Analyses of kinetic data suggest that the surface of the sodium carbonate particles may be much hotter than the bulk gas due to the highly exothermic reaction with carbon dioxide and water, and that the rate of heat removal from the particle may control the reaction rate. A material and energy balance was developed for a cyclic carbonation/calcination process which captures about 26 percent of the carbon dioxide present in flue gas available at 250 C.

  17. Dual layer hollow fiber sorbents for trace H2S removal from gas streams

    KAUST Repository

    Bhandari, Dhaval A.

    2013-05-01

    Hollow fiber sorbents are pseudo monolithic materials with potential use in various adsorption based applications. Dual layer hollow fiber sorbents have the potential to allow thermal regeneration without direct contact of the regeneration fluid with the sorbent particles. This paper considers the application of dual layer hollow fiber sorbents for a case involving trace amounts of H2S removal from a simulated gas stream and offers a comparison with single layer hollow fiber sorbents. The effect of spin dope composition and core layer zeolite loading on the gas flux, H2S transient sorption capacity and pore structure are also studied. This work can be used as a guide to develop and optimize dual layer hollow fiber sorbent properties beyond the specific example considered here. © 2013 Elsevier Ltd.

  18. HYPERTHERMIA, INTRACELLULAR FREE CALCIUM AND CALCIUM IONOPHORES

    NARCIS (Netherlands)

    STEGE, GJJ; WIERENGA, PK; KAMPINGA, HH; KONINGS, AWT

    1993-01-01

    It is shown that heat-induced increase of intracellular calcium does not correlate with hyperthermic cell killing. Six different cell lines were investigated; in four (EAT, HeLa S3, L5178Y-R and L5178Y-S) heat treatments killing 90% of the cells did not affect the levels of intracellular free calciu

  19. Thermodynamic Properties of CO{sub 2} Capture Reaction by Solid Sorbents: Theoretical Predictions and Experimental Validations

    Energy Technology Data Exchange (ETDEWEB)

    Duan, Yuhua; Luebke, David; Pennline, Henry; Li, Liyu; King, David; Zhang,; Keling,; Zhao,; Lifeng,; Xiao, Yunhan

    2012-01-01

    It is generally accepted that current technologies for capturing CO{sub 2} are still too energy intensive. Hence, there is a critical need for development of new materials that can capture CO{sub 2} reversibly with acceptable energy costs. Accordingly, solid sorbents have been proposed to be used for CO{sub 2} capture applications through a reversible chemical transformation. By combining thermodynamic database mining with first principles density functional theory and phonon lattice dynamics calculations, a theoretical screening methodology to identify the most promising CO{sub 2} sorbent candidates from the vast array of possible solid materials has been proposed and validated. The calculated thermodynamic properties of different classes of solid materials versus temperature and pressure changes were further used to evaluate the equilibrium properties for the CO{sub 2} adsorption/desorption cycles. According to the requirements imposed by the pre- and post- combustion technologies and based on our calculated thermodynamic properties for the CO{sub 2} capture reactions by the solids of interest, we were able to screen only those solid materials for which lower capture energy costs are expected at the desired pressure and temperature conditions. These CO{sub 2} sorbent candidates were further considered for experimental validations. In this presentation, we first introduce our screening methodology with validating by solid dataset of alkali and alkaline metal oxides, hydroxides and bicarbonates which thermodynamic properties are available. Then, by studying a series of lithium silicates, we found that by increasing the Li{sub 2}O/SiO{sub 2} ratio in the lithium silicates their corresponding turnover temperatures for CO{sub 2} capture reactions can be increased. Compared to anhydrous K{sub 2}CO{sub 3}, the dehydrated K{sub 2}CO{sub 3}1.5H{sub 2}O can only be applied for post-combustion CO{sub 2} capture technology at temperatures lower than its phase transition (to

  20. Decontamination of waste waters and soils from heavy metals using artificial aluminosilicate sorbents

    International Nuclear Information System (INIS)

    The physico-chemical properties of the commercial artificial aluminosilicate sorbent 'beringite' and a newly prepared sorbents (named 'S') were tested in order to test compare usefulness for decontamination of waste waters from heavy metals. Beringite and lime doses were applied to contaminated soils and their effects on plants growth and heavy metals uptake were estimated. The test showed a possible better usefulness of 'S' sorbents for waste water treatment. On the soils studied no differences between beringite and lime application were detected

  1. ISOLATION OF URANIUM(VI) AND THORIUM(IV) FROM AQUEOUS SOLUTIONS BY INORGANIC SORBENTS

    OpenAIRE

    Menchuk, V. V.; Perlova, N. A.

    2016-01-01

    Efficiency of use of a new sorbent on the basis of a silica gel at uranium and thorium isolation from their diluted aqueous solutions was investigated. It is shown that the investigated sorbent sorbs uranium and thorium better than a known sorbent (the silica gel). Influence of phases contact time, pH, the metal nature and solution ionic composition on the efficiency of uranium and thorium sorption process was studied. Experimentally received isotherms sorption are described by means of Langm...

  2. Application of Commercial Sorbent into Coal-derived Syngas Desulfurization Field for Clean Coal technologies Development

    OpenAIRE

    Chien, H.-Y.

    2015-01-01

    Advanced applications of producer gas (e.g. fuel cells, catalytic processes for liquid fuels production) require deep gas cleaning. Dry desulfurization technologies of fuel gas select appropriate sorbents according to material’s physical and chemical properties like sulfur capacity, attainable sulphur concentration in gas, price, etc.. The properties of a commercial sorbent were determined by means of XRD, ICP-OES, SEM and surface area measurement. The main components of the sorbent were ZnO,...

  3. Evaluation of single-walled carbon nanohorns as sorbent in dispersive micro solid-phase extraction

    International Nuclear Information System (INIS)

    Highlights: ► The potential of single walled carbon nanohorns in dispersive solid phase microextraction has been evaluated. ► The method was characterized for the extraction of PAHs from waters. ► Single walled carbon nanohorns were better extractant than carbon nanotubes and carbon nanocones. ► The limits of detection were adequate for the target analytes in environmental waters. - Abstract: A new dispersive micro solid-phase extraction method which uses single-walled carbon nanohorns (SWNHs) as sorbent is proposed. The procedure combines the excellent sorbent properties of the nanoparticles with the efficiency of the dispersion of the material in the sample matrix. Under these conditions, the interaction with the analytes is maximized. The determination of polycyclic aromatic hydrocarbons was selected as model analytical problem. Two dispersion strategies were evaluated, being the functionalization via microwave irradiation better than the use of a surfactant. The extraction was accomplished by adding 1 mL of oxidized SWHNs (o-SWNHs) dispersion to 10 mL of water sample. After extraction, the mixture was passed through a disposable Nylon filter were the nanoparticles enriched with the PAHs were retained. The elution was carried out with 100 μL of hexane. The limits of detection achieved were between 30 and 60 ng L−1 with a precision (as repeatability) better than 12.5%. The recoveries obtained for the analytes in three different water samples were acceptable in all instances. The performance of o-SWNHs was favourably compared with that provided by carboxylated single-walled carbon nanotubes and thermally treated carbon nanocones.

  4. Magnetic sorbents added to soil slurries lower Cr aqueous concentration

    Science.gov (United States)

    Aravantinos, Konstantinos; Isari, Ekavi; Karapanagioti, Hrissi K.; Manariotis, Ioannis D.; Werner, David

    2016-04-01

    Activated carbon (AC) acts as a strong binding agent that lowers the pollutant concentration and, thus its toxicity. Another promising sorbent material in environmental applications is biochar (BC) which is obtained from the incomplete combustion of carbon-rich biomass under oxygen-limited conditions. Both of these materials could be used as soil or sediment amendments that would lower the toxicity in the aqueous phase. A draw back of this technique is that although the pollutant will remain non- bioavailable for many years being sorbed into these sorbents, it actually stays into the system. The objective of this study was (a) to synthesize a magnetic powdered activated carbon (AC/Fe) and magnetic powdered biochar (BC/Fe) produced from a commercial AC sample and BC, respectively and (b) to evaluate the potential use of AC/Fe and BC/Fe to lower Cr concentration that desorb from two soils in their soil slurries. The two soil samples originate from the vicinity of a local metal shop. The BC was produced from olive pomace. The surface area, the pore volume, and the average pore size of each sorbent were determined using gas (N2) adsorption-desorption cycles and the Brunauer, Emmett, and Teller (BET) equation. Isotherms with 30 adsorption and 20 desorption points were conducted at liquid nitrogen temperature (77K). Open surface area and micropore volume were determined using t-plot method and Harkins & Jura equation. For both AC/Fe, surface area measurements resulted in 66% those of corresponding AC. For BC/Fe, the surface area was 82% that of BC. Our previous studies have shown that both AC/Fe and BC/Fe are effective sorbents for mercury in aqueous solutions but with lower sorption capacity compared to the initial materials (50-75% lower). Batch experiments with all sorbent samples and each soil were conducted at room temperature (25oC) in order to compare the sorption properties of the materials. The soil slurries demonstrated low Cr concentrations (10.9 and 14.6

  5. Attrition resistant catalysts and sorbents based on heavy metal poisoned FCC catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Gangwal, S.; Jothimurugesan, K.

    1999-07-27

    A heavy metal poisoned, spent FCC catalyst is treated by chemically impregnating the poisoned catalyst with a new catalytic metal or metal salt to provide an attrition resistant catalyst or sorbent for a different catalytic or absorption process, such as catalysts for Fischer-Tropsh Synthesis, and sorbents for removal of sulfur gases from fuel gases and flue-gases. The heavy metal contaminated FCC catalyst is directly used as a support for preparing catalysts having new catalytic properties and sorbents having new sorbent properties, without removing or passivating the heavy metals on the spent FCC catalyst as an intermediate step.

  6. Attrition resistant catalysts and sorbents based on heavy metal poisoned FCC catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Gangwal, Santosh (Cary, NC); Jothimurugesan, Kandaswamy (Hampton, VA)

    1999-01-01

    A heavy metal poisoned, spent FCC catalyst is treated by chemically impregnating the poisoned catalyst with a new catalytic metal or metal salt to provide an attrition resistant catalyst or sorbent for a different catalytic or absorption processes, such as catalysts for Fischer-Tropsh Synthesis, and sorbents for removal of sulfur gasses from fuel gases and flue-gases. The heavy metal contaminated FCC catalyst is directly used as a support for preparing catalysts having new catalytic properties and sorbents having new sorbent properties, without removing or "passivating" the heavy metals on the spent FCC catalyst as an intermediate step.

  7. Iron blast furnace slag/hydrated lime sorbents for flue gas desulfurization.

    Science.gov (United States)

    Liu, Chiung-Fang; Shih, Shin-Min

    2004-08-15

    Sorbents prepared from iron blast furnace slag (BFS) and hydrated lime (HL) through the hydration process have been studied with the aim to evaluate their reactivities toward SO2 under the conditions prevailing in dry or semidry flue gas desulfurization processes. The BFS/HL sorbents, having large surface areas and pore volumes due to the formation of products of hydration, were highly reactive toward SO2, as compared with hydrated lime alone (0.24 in Ca utilization). The sorbent reactivity increased as the slurrying temperature and time increased and as the particle size of BFS decreased; the effects of the liquid/solid ratio and the sorbent drying conditions were negligible. The structural properties and the reactivity of sorbent were markedly affected by the BFS/HL ratio; the sorbent with 30/70 ratio had the highest 1 h utilization of Ca, 0.70, and SO2 capture, 0.45 g SO2/g sorbent. The reactivity of a sorbent was related to its initial specific surface area (Sg0) and molar content of Ca (M(-1)); the 1 h utilization of Ca increased almost linearly with increasing Sg0/M. The results of this study are useful to the preparation of BFS/HL sorbents with high reactivity for use in the dry and semidry processes to remove SO2 from the flue gas. PMID:15382877

  8. Methane preconcentration in a microtrap using multiwalled carbon nanotubes as sorbents.

    Science.gov (United States)

    Saridara, Chutarat; Ragunath, Smruti; Pu, Yong; Mitra, Somenath

    2010-09-10

    The GC monitoring of green house gases is a challenging task because the concentration of organic species such as methane are relatively low (ppm to ppb) and their analysis requires some level of preconcentration. Since methane is highly volatile, it is not easily retained on conventional sorbents. In this paper we present multiwalled carbon nanotubes (MWNTs) as an effective sorbent for a microtrap designed for methane preconcentration. Its performance was compared to other commercially available carbon based sorbents, and it was found to be the most effective sorbent in terms of breakthrough volume and enthalpy of adsorption. PMID:20850589

  9. Use of different sorbents in the semidry FGD process with a powder-particle spouted bed

    Energy Technology Data Exchange (ETDEWEB)

    Xiaoxun Ma; Tsutomu Nakazato; Guangwen Xu; Chang Wang; Nobuyoshi Nakagawa; Kunio Kato [Northwest University, Xi' an (China)

    2005-07-01

    To explore more SO{sub 2} sorbents applicable in the semidry FGD process of powder-particle spouted bed (PPSB), effects of operating conditions and the components of flue gas on SO{sub 2} removal efficiency were investigated with several sorbents. SO{sub 2} removal efficiency of different sorbents was compared and the ways to enhance SO{sub 2} removal efficiency were discussed. Hydrated lime, limestone, magnesium hydroxide and concrete pile sludge particles were used as sorbents. 12 refs., 7 figs., 3 tabs.

  10. Water Vapor Desorption Characteristics of Honeycomb Type Sorption Element Composed of Organic Sorbent

    Science.gov (United States)

    Inaba, Hideo; Kida, Takahisa; Horibe, Akihiko; Kaneda, Makoto; Okamoto, Tamio; Seo, Jeong-Kyun

    This paper describes the water vapor desorption characteristics of honeycomb shape type sorbent element containing new organic sorbent of the bridged complex of sodium polyacrylate. The transient experiments in which the dry air was passed into the honeycomb type sorbent element sorbed water vapor were carried out under various conditions of air velocity, temperature, relative humidity and honeycomb length. The obtained data for desorption process were compared with those for sorption process. Finally, Sherwood number of mass transfer of the organic sorbent for desorption process was derived in terms of Reynolds number, modified Stefan number and non-dimensional honeycomb length.

  11. Desulfurization of liquid fuels by adsorption on carbon-based sorbents and ultrasound-assisted sorbent regeneration.

    Science.gov (United States)

    Wang, Yuhe; Yang, Ralph T

    2007-03-27

    Several carbon-based adsorbents, CuCl/AC, PdCl2/AC, and Pd/AC (where AC denotes activated carbon), were studied for desulfurization of a model jet fuel by selective adsorption of thiophenic molecules. Comparisons with gamma-Al2O3 support and desulfurization of a commercial jet fuel were also studied. The results showed that the selective sulfur adsorption capacity of PdCl2 was higher than that of CuCl and Pd(0), in agreement with molecular orbital results. It was also found that the activated carbon is the best support for pi-complexation sorbents to remove sulfur-containing compounds, i.e., benzothiophene and methylbenzothiophene. Among all the adsorbents studied, PdCl2/AC had the highest capacity for desulfurization. A significant synergistic effect was observed between the carbon substrate and the supported pi-complexation sorbent, and this effect was explained by a geometric effect. The saturated sorbent was regenerated by desorption assisted by ultrasound with a solvent of 30 wt % benzene and 70 wt % n-octane. The results showed that the amount of sulfur desorbed was higher with ultrasound, 65 wt % desorption vs 45 wt % without ultrasound in a static system at 50 degrees C. PMID:17315903

  12. CARBON DIOXIDE CAPTURE FROM FLUE GAS USING DRY REGENERABLE SORBENTS

    Energy Technology Data Exchange (ETDEWEB)

    David A. Green; Brian S. Turk; Raghubir P. Gupta; William J. McMichael; Douglas P. Harrison; Ya Liang

    2002-01-01

    The objective of this project is to develop a simple, inexpensive process to separate CO{sub 2} as an essentially pure stream from a fossil fuel combustion system using a regenerable, sodium-based sorbent. The sorbent being used in this project is sodium carbonate which is converted to sodium bicarbonate, or ''baking soda,'' through reaction with carbon dioxide and water vapor. Sodium bicarbonate is regenerated to sodium carbonate when heated, producing a nearly pure CO{sub 2} stream after condensation of water vapor. This quarter, five cycle thermogravimetric tests were conducted at the Louisiana State University (LSU) with sodium bicarbonate Grade 3 (SBC{number_sign}3) which showed that carbonation activity declined slightly over 5 cycles following severe calcination conditions of 200 C in pure CO{sub 2}. Three different sets of calcination conditions were tested. Initial carbonation activity (as measured by extent of reaction in the first 25 minutes) was greatest subsequent to calcination at 120 C in He, slightly less subsequent to calcination in 80% CO{sub 2}/20% H{sub 2}O, and lowest subsequent to calcination in pure CO{sub 2} at 200 C. Differences in the extent of reaction after 150 minutes of carbonation, subsequent to calcination under the same conditions followed the same trend but were less significant. The differences between fractional carbonation under the three calcination conditions declined with increasing cycles. A preliminary fixed bed reactor test was also conducted at LSU. Following calcination, the sorbent removed approximately 19% of the CO{sub 2} in the simulated flue gas. CO{sub 2} evolved during subsequent calcination was consistent with an extent of carbonation of approximately 49%. Following successful testing of SBC{number_sign}3 sorbent at RTI reported in the last quarter, a two cycle fluidized bed reactor test was conducted with trona as the sorbent precursor, which was calcined to sodium carbonate. In the first

  13. Neuronal calcium sparks and intracellular calcium “noise”

    OpenAIRE

    Melamed-Book, Naomi; Kachalsky, Sylvia G.; Kaiserman, Igor; Rahamimoff, Rami

    1999-01-01

    Intracellular calcium ions are involved in many forms of cellular function. To accommodate so many control functions, a complex spatiotemporal organization of calcium signaling has developed. In both excitable and nonexcitable cells, calcium signaling was found to fluctuate. Sudden localized increases in the intracellular calcium concentration—or calcium sparks—were found in heart, striated and smooth muscle, Xenopus Laevis oocytes, and HeLa and P12 cells. In the nervous system, intracellular...

  14. Development and testing of inorganic sorbents made by the internal gelation process for radionuclide and heavy metal separations

    International Nuclear Information System (INIS)

    The objectives of this task are to develop, prepare, and test microspheres and granular forms of inorganic ion exchangers to remove radionuclides and heavy metals from waste streams occurring at various sites. Several inorganic materials, such as hexacyanoferrates, titanates, phosphates, and oxides have high selectivities and efficiencies for separating and removing radionuclides such as uranium, technetium, cesium, and strontium, and metals such as cobalt, silver, zinc, and zirconium from aqueous waste streams. However, these sorbents frequently exist only as powders and consequently are not readily adaptable to continuous processing such as column chromatography. Making these inorganic ion exchangers as microspheres or granular forms improves the flow dynamics for column operations and expands their practical applications. Microspheres of several materials have been prepared at ORNL, and the effectiveness of zirconium monohydrogen phosphate and hydrous titanium oxide microspheres for removing radionuclides from hot cell waste solutions has been demonstrated

  15. Calcium addition in straw gasification

    DEFF Research Database (Denmark)

    Risnes, H.; Fjellerup, Jan Søren; Henriksen, Ulrik Birk;

    2003-01-01

    The present work focuses on the influence of calcium addition in gasification. The inorganic¿organic element interaction as well as the detailed inorganic¿inorganic elements interaction has been studied. The effect of calcium addition as calcium sugar/molasses solutions to straw significantly...... affected the ash chemistry and the ash sintering tendency but much less the char reactivity. Thermo balance test are made and high-temperature X-ray diffraction measurements are performed, the experimental results indicate that with calcium addition major inorganic¿inorganic reactions take place very late...... calcium binds silicon primarily as calcium silicates and less as potassium calcium silicates....

  16. Highly effective sorbents obtained by treating agrowaste products in cold plasma

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Sorbents are widely used in purification of various liquids and gases, offering a universal means for wastewater and air cleaning. The most promising sorbents are those obtained from agrowaste products such as rice or buckwheat husk. Processing of husk in cold plasma modifies the composition, structure and surface properties of the raw material and raises its porosity, thus substantially improving the sorption properties of the final product.Husk as a raw material for producing sorbents has the following advantageous properties: (1) appropriate chemical composition; (2) low cost; (3) high dispersity, due to which there is no need in any special treatment of the material prior to its exposing to plasma; (4) scaly structure and developed porous surface ensuring a high surface-to-volume ratio. The best properties are displayed by the sorbents obtained in cold plasma under reduced pressures of 53.2 Pa. The raw naterial traverses the region occupied by the plasma and, as it does so, it gets heated up to a temperature of 250 - 350 ℃. The whole process involves two stages: combustion of the raw material and modification of its properties under the action of the plasma. The combustion proceeds due to the oxygen contained in the starting material. During the combustion, the hydrogen contained in the starting material and some part of the carbon also burn out.The resultant scaly sorbent is accumulated in a cooler. The scales are black; they range in sizes from 1mm to 5 mm.The sorbents obtained are remarkable for their useful properties and outperform most of the traditional sorbents used in modern industry. The starting materials are inexpensive, and their resources are almost unlimited. The sorbents have rather a low production cost (1.8-2.5($)/kg). The sorbents can be used for cleaning hydrosphere from water pollutants on a large scale. The degree of cleaning water surface from oil products with sorbents was a subject of investigation. The highest degree of purification

  17. ASSESSMENT OF LOW COST NOVEL SORBENTS FOR COAL-FIRED POWER PLANT MERCURY CONTROL

    Energy Technology Data Exchange (ETDEWEB)

    Sharon Sjostrom

    2004-03-01

    The injection of sorbents upstream of a particulate control device is one of the most promising methods for controlling mercury emissions from coal-fired utility boilers with electrostatic precipitators and fabric filters. Studies carried out at the bench-, pilot-, and full-scale have shown that a wide variety of factors may influence sorbent mercury removal effectiveness. These factors include mercury species, flue gas composition, process conditions, existing pollution control equipment design, and sorbent characteristics. The objective of the program is to obtain the necessary information to assess the viability of lower cost alternatives to commercially available activated carbon for mercury control in coal-fired utilities. Prior to injection testing, a number of sorbents were tested in a slipstream fixed-bed device both in the laboratory and at two field sites. Based upon the performance of the sorbents in a fixed-bed device and the estimated cost of mercury control using each sorbent, seventeen sorbents were chosen for screening in a slipstream injection system at a site burning a Western bituminous coal/petcoke blend, five were chosen for screening at a site burning a subbituminous Powder River Basin (PRB) coal, and nineteen sorbents were evaluated at a third site burning a PRB coal. Sorbents evaluated during the program were of various materials, including: activated carbons, treated carbons, other non-activated carbons, and non-carbon material. The economics and performance of the novel sorbents evaluated demonstrate that there are alternatives to the commercial standard. Smaller enterprises may have the opportunity to provide lower price mercury sorbents to power generation customers under the right set of circumstances.

  18. Calcium binding by dietary fibre

    International Nuclear Information System (INIS)

    Dietary fibre from plants low in phytate bound calcium in proportion to its uronic-acid content. This binding by the non-cellulosic fraction of fibre reduces the availability of calcium for small-intestinal absorption, but the colonic microbial digestion of uronic acids liberates the calcium. Thus the ability to maintain calcium balance on high-fibre diets may depend on the adaptive capacity on the colon for calcium. (author)

  19. [Calcium suppletion for patients who use gastric acid inhibitors: calcium citrate or calcium carbonate?].

    NARCIS (Netherlands)

    Jonge, H.J. de; Gans, R.O.; Huls, G.A.

    2012-01-01

    Various calcium supplements are available for patients who have an indication for calcium suppletion. American guidelines and UpToDate recommend prescribing calcium citrate to patients who use antacids The rationale for this advice is that water-insoluble calcium carbonate needs acid for adequate ab

  20. Calcium Silicate-Based Cements Associated with Micro- and Nanoparticle Radiopacifiers: Physicochemical Properties and Bioactivity

    OpenAIRE

    BOSSO-MARTELO, Roberta; Juliane Maria GUERREIRO-TANOMARU; Viapiana, Raqueli; Berbert, Fábio Luis Camargo Vilella; Basso Bernardi, Maria Inês; Tanomaru-Filho, Mario

    2015-01-01

    Objective. The aim of this study was to evaluate the physicochemical properties and bioactivity of two formulations of calcium silicate-based cements containing additives (CSCM) or resin (CSCR), associated with radiopacifying agents zirconium oxide (ZrO2) and niobium oxide (Nb2O5) as micro- and nanoparticles; calcium tungstate (CaWO4); and bismuth oxide (Bi2O3). MTA Angelus was used as control. Methods. Surface features and bioactivity were evaluated by scanning electron microscopy and the ch...