Sample records for caso4 oxygen carrier

  1. Chemical-looping combustion of methane with CaSO4 oxygen carrier in a fixed bed reactor

    International Nuclear Information System (INIS)

    Chemical-looping combustion is a promising technology for the combustion of gas or solid fuel with efficient use of energy and inherent separation of CO2. Chemical-looping combustion of methane with calcium sulfate as a novel oxygen carrier was conducted in a laboratory scale fixed bed reactor. The effects of reaction temperature, gas flow rate, sample mass, and particle size on reduction reactions were investigated and an optimum operating condition was determined. The results show that this novel oxygen carrier has a high reduction reactivity and stability in a long-time reduction/oxidation test. The conversions of CH4 increased with a higher temperature, smaller gas flow rate, larger sample mass and smaller particle size. The suitable reaction temperature seems to be around 950 deg. C. Low temperatures lead to a low CH4 conversion, but a significant SO2 formation was observed at a higher temperature. The release of SO2, CO, H2 via a series of side reactions, carbon deposition and agglomeration were also discussed. The formation of SO2, CO, H2, and carbon can be avoided by optimization of the operating conditions

  2. Effect of Gasifying Medium on the Coal Chemical Looping Gasification with CaSO4 as Oxygen Carrier☆

    Institute of Scientific and Technical Information of China (English)

    Yongzhuo Liu; Weihua Jia; Qingjie Guo; Hojung Ryu


    The chemical looping gasification uses an oxygen carrier for solid fuel gasification by supplying insufficient lattice oxygen. The effect of gasifying medium on the coal chemical looping gasification with CaSO4 as oxygen carrier is investigated in this paper. The thermodynamical analysis indicates that the addition of steam and CO2 into the system can reduce the reaction temperature, at which the concentration of syngas reaches its maximum value. Experimental result in thermogravimetric analyzer and a fixed-bed reactor shows that the mixture sample goes through three stages, drying stage, pyrolysis stage and chemical looping gasification stage, with the temper-ature for three different gaseous media. The peak fitting and isoconversional methods are used to determine the reaction mechanism of the complex reactions in the chemical looping gasification process. It demonstrates that the gasifying medium (steam or CO2) boosts the chemical looping process by reducing the activation energy in the overall reaction and gasification reactions of coal char. However, the mechanism using steam as the gasifying medium differs from that using CO2. With steam as the gasifying medium, parallel reactions occur in the begin-ning stage, followed by a limiting stage shifting from a kinetic to a diffusion regime. It is opposite to the reaction mechanism with CO2 as the gasifying medium.

  3. Investigation into Syngas Generation from Solid Fuel Using CaSO4-based Chemical Looping Gasification Process

    Institute of Scientific and Technical Information of China (English)

    LIU Yongzhuo; GUO Qingjie


    Chemical-looping gasification(CLG)is a novel process for syngas generation from solid fuels,sharing the same basic principles as chemical-looping combustion(CLC).It also uses oxygen carriers(mainly metal oxide and calcium sulfate)to transfer heat and oxygen to the fuel.In this paper,the primary investigation into the CLG process with CaSO4 as oxygen carrier was carried out by thermodynamic analysis and experiments in the tube reactor.Sulfur-contained gas emission was mainly H2S rather than SO2 in the CLG process,showing some different features from the CLC.The mass and heat balance of CLG processes were calculated thermodynamically to determinate the auto-thermal operating conditions with different CaSO4/C and steam/C molar ratios.It was found that the CaSO4/C molar ratio should be higher than 0.2 to reach auto-thermal balance.The effect of temperature on the reactions between oxygen carrier and coal was investigated based on Gibbs free energy minimum method and experimental results.It indicated that high temperature favored the CLG process in the fuel reactor and part of syngas was consumed to compensate for auto-thermal system.

  4. Synthesis gas production using oxygen storage materials as oxygen carrier over circulating fluidized bed

    Institute of Scientific and Technical Information of China (English)

    DAI Xiaoping; YU Changchun; LI Ranjia; WU Qiong; HAO Zhengping


    A novel process for synthesis gas production over Circulating Fluidized Bed (CFB) using oxygen storage materials as oxygen carrier was reported. First, oxygen in the air was chemically fixed and converted to lattice oxygen of oxygen storage materials over regenerator, and then methane was selectively oxidized to synthesis gas with lattice oxygen of oxygen storage materials over riser reactor. The results from simulation reaction of CFB by sequential redox reaction on a fixed bed reactor using lanthanum-based perovskite LaFeO3 and La0.8Sr0.2Fe0.9Co0.1O3 oxides prepared by sol-gel, suggested that the depleted oxygen species could be regenerated, and methane could be oxidized to synthesis gas by lattice oxygen with high selectivity. The partial oxidation of methane to synthesis gas over CFB using lattice oxygen of the oxygen storage materials instead of gaseous oxygen should be possibly applicable.

  5. Enhanced optical oxygen sensing using a newly synthesized ruthenium complex together with oxygen carriers. (United States)

    Ertekin, Kadriye; Kocak, Suleyman; Sabih Ozer, M; Aycan, Sule; Cetinkaya, Bekir


    In this article, an emission based, simple and fast method is proposed for the determination of gaseous oxygen. A newly synthesized fluorophore, dichloro-{2,6-bis[1-(4-dimethylamino-phenylimino) ethyl]pyridine}ruthenium(II) has been used for oxygen sensing together with oxygen carrier perfluorochemicals (PFCs) in silicon matrix. It should be noted that the solubility of oxygen in fluorocarbons is about three to ten times large as that observed in the parent hydrocarbons or in water, respectively. Employed PFCs are chemically and biochemically inert, have high dissolution capacities for oxygen, and, once doped into sensing film, considerably enhance the response of sensing agent. PMID:18969220

  6. Natural Ores as Oxygen Carriers in Chemical Looping Combustion

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Hanjing; Siriwardane, Ranjani; Simonyi, Thomas; Poston, James


    Chemical looping combustion (CLC) is a combustion technology that utilizes oxygen from oxygen carriers (OC), such as metal oxides, instead of air to combust fuels. The use of natural minerals as oxygen carriers has advantages, such as lower cost and availability. Eight materials, based on copper or iron oxides, were selected for screening tests of CLC processes using coal and methane as fuels. Thermogravimetric experiments and bench-scale fixed-bed reactor tests were conducted to investigate the oxygen transfer capacity, reaction kinetics, and stability during cyclic reduction/oxidation reaction. Most natural minerals showed lower combustion capacity than pure CuO/Fe{sub 2}O{sub 3} due to low-concentrations of active oxide species in minerals. In coal CLC, chryscolla (Cu-based), magnetite, and limonite (Fe-based) demonstrated better reaction performances than other materials. The addition of steam improved the coal CLC performance when using natural ores because of the steam gasification of coal and the subsequent reaction of gaseous fuels with active oxide species in the natural ores. In methane CLC, chryscolla, hematite, and limonite demonstrated excellent reactivity and stability in 50-cycle thermogravimetric analysis tests. Fe{sub 2}O{sub 3}-based ores possess greater oxygen utilization but require an activation period before achieving full performance in methane CLC. Particle agglomeration issues associated with the application of natural ores in CLC processes were also studied by scanning electron microscopy (SEM).

  7. Evaluation of different oxygen carriers for biomass tar reforming

    DEFF Research Database (Denmark)

    Mendiara, Teresa; Johansen, Joakim Myung; Utrilla, Rubén;


    This work is a continuation of a previous paper by the authors [1] which analyzed the suitability of the Chemical Looping technology in biomass tar reforming. Four different oxygen carriers were tested with toluene as tar model compound: 60% NiO/MgAl2O4 (Ni60), 40% NiO/NiAl2O4 (Ni40), 40% Mn3O4/Mg......–ZrO2 (Mn40) and FeTiO3 (Fe) and their tendency to carbon deposition was analyzed in the temperature range 873–1073K. In the present paper, the reactivity of these carriers to other compounds in the gasification gas is studied, also with special emphasis on the tendency to carbon deposition. Experiments...... were carried out in a TGA apparatus and a fixed bed reactor. Ni-based carriers showed a tendency to form carbon in the reaction with CH4, especially Ni60. The addition of water in H2O/CH4 molar ratios of 0.4–2.3 could decrease the carbon deposited, but not in the case of Ni60. Mn-based sample reacted...

  8. Thermal Analysis and Investigation of NiO-Based Oxygen Carriers for Chemical-Looping Combustion

    Energy Technology Data Exchange (ETDEWEB)

    Jerndal, Erik, e-mail:


    Capture and storage of CO{sub 2} can be used to reduce greenhouse gas emissions from combustion of fossil fuels. Chemical-looping combustion is a two-step combustion process where CO{sub 2} is obtained in a separate stream, ready for compression and storage. The technology uses circulating oxygen carriers to transfer oxygen from an air reactor to a fuel reactor, thus avoiding an energy consuming gas separation unit. A thermal analysis of the process using a large number of possible oxygen carriers was performed by simulating chemical reactions. Based on the ability of the oxygen carriers to convert different gaseous fuels, stability in air and melting temperature some metal oxides based on Ni, Cu, Fe, Mn, Co, W and sulphates of Ba, Sr and Ca showed good thermodynamic properties and could be feasible as oxygen carriers. The promising systems were investigated further with respect to temperature changes in the fuel reactor as well as possible formation of carbon, sulphides and sulphates which may deactivate the oxygen carriers. Oxygen carriers of NiO, supported by NiAl{sub 2}O{sub 4}, were prepared and investigated experimentally with respect to parameters important for chemical-looping combustion. These oxygen carriers were based on commercially available raw materials in contrast to most of the previously tested oxygen carriers, which have been prepared from pure chemicals. Further, it was investigated if spray-drying, which is a production method suitable for large-scale particle preparation, can be used to produce high performing oxygen carriers instead of the small-scale freeze-granulation method. Generally, materials prepared from commercially available raw material showed high reactivity with methane and oxygen. Oxygen carriers prepared by spray-drying, displayed a remarkable similarity when compared to oxygen carriers prepared from the same starting material by freeze-granulation, both regarding physical properties and reactivity. Further, the up-scaling of

  9. Syngas Generation from Methane Using a Chemical-Looping Concept: A Review of Oxygen Carriers

    Directory of Open Access Journals (Sweden)

    Kongzhai Li


    Full Text Available Conversion of methane to syngas using a chemical-looping concept is a novel method for syngas generation. This process is based on the transfer of gaseous oxygen source to fuel (e.g., methane by means of a cycling process using solid oxides as oxygen carriers to avoid direct contact between fuel and gaseous oxygen. Syngas is produced through the gas-solid reaction between methane and solid oxides (oxygen carriers, and then the reduced oxygen carriers can be regenerated by a gaseous oxidant, such as air or water. The oxygen carrier is recycled between the two steps, and the syngas with a ratio of H2/CO = 2.0 can be obtained successively. Air is used instead of pure oxygen allowing considerable cost savings, and the separation of fuel from the gaseous oxidant avoids the risk of explosion and the dilution of product gas with nitrogen. The design and elaboration of suitable oxygen carriers is a key issue to optimize this method. As one of the most interesting oxygen storage materials, ceria-based and perovskite oxides were paid much attention for this process. This paper briefly introduced the recent research progresses on the oxygen carriers used in the chemical-looping selective oxidation of methane (CLSOM to syngas.

  10. Combined oxides as oxygen-carrier material for chemical-looping with oxygen uncoupling

    International Nuclear Information System (INIS)

    Highlights: • Manganese-based combined oxides are examined for chemical-looping combustion applications. • Promising compositions includes (MnyFe1−y)Ox, (MnySi1−y)Ox and CaMnO3−δ. • Study includes thermodynamic analysis and overview of current experimental experiences. - Abstract: Oxygen-carrier materials for chemical-looping with oxygen uncoupling (CLOU) must be capable of taking up and releasing gas-phase O2 at conditions relevant for generation of heat and power. In principle, the capability of a certain material to do so is determined by its thermodynamic properties. This paper provides an overview of the possibility to design feasible oxygen carrier materials from combined oxides, i.e. oxides with crystal structures that include several different cations. Relevant literature is reviewed and the thermodynamic properties and key characteristics of a few selected combined oxide systems are calculated and compared to experimental data. The general challenges and opportunities of the combined oxide concept are discussed. The focus is on materials with manganese as one of its components and the following families of compounds and solid solutions have been considered: (MnyFe1−y)Ox, (MnySi1−y)Ox, CaMnO3−δ, (NiyMn1−y)Ox, (MnyCu1−y)Ox and (MnyMg1−y)Ox. In addition to showing promise from a thermodynamic point of view, reactivity data from experimental investigations suggests that the rate of O2 release can be high for all systems. Thus these combined oxides could also be very suitable for practical application

  11. Recovery Act: Novel Oxygen Carriers for Coal-fueled Chemical Looping

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Wei-Ping; Cao, Yan


    Chemical Looping Combustion (CLC) could totally negate the necessity of pure oxygen by using oxygen carriers for purification of CO{sub 2} stream during combustion. It splits the single fuel combustion reaction into two linked reactions using oxygen carriers. The two linked reactions are the oxidation of oxygen carriers in the air reactor using air, and the reduction of oxygen carriers in the fuel reactor using fuels (i.e. coal). Generally metal/metal oxides are used as oxygen carriers and operated in a cyclic mode. Chemical looping combustion significantly improves the energy conversion efficiency, in terms of the electricity generation, because it improves the reversibility of the fuel combustion process through two linked parallel processes, compared to the conventional combustion process, which is operated far away from its thermo-equilibrium. Under the current carbon-constraint environment, it has been a promising carbon capture technology in terms of fuel combustion for power generation. Its disadvantage is that it is less mature in terms of technological commercialization. In this DOE-funded project, accomplishment is made by developing a series of advanced copper-based oxygen carriers, with properties of the higher oxygen-transfer capability, a favorable thermodynamics to generate high purity of CO{sub 2}, the higher reactivity, the attrition-resistance, the thermal stability in red-ox cycles and the achievement of the auto-thermal heat balance. This will be achieved into three phases in three consecutive years. The selected oxygen carriers with final-determined formula were tested in a scaled-up 10kW coal-fueled chemical looping combustion facility. This scaled-up evaluation tests (2-day, 8-hour per day) indicated that, there was no tendency of agglomeration of copper-based oxygen carriers. Only trace-amount of coke or carbon deposits on the copper-based oxygen carriers in the fuel reactor. There was also no evidence to show the sulphidization of oxygen

  12. Dosimetric properties of CaSO4: Dy thermoluminescent material

    International Nuclear Information System (INIS)

    The new ICRP regulations about radiological protection allows the different groups to study new high sensitivity thermoluminescent materials for dosimetric applications (personal and environmental). Different concentrations of Dy as dopant in the thermoluminescent material CaSO4 have been studied. The concentration usually encountered in bibliography for the CaSO4 is 0.1%. Our group have chosen the 1% Dy concentration due to its high sensitivity, the ratio for the CaSO4: Dy (1%) over the CaSO4: Dy (0.1%) is close to 3. The results obtained for the habitual set of tests (homogeneity, reproducibility, detection threshold, energy response and fading) reveals CaSO4: Dy (1%) as an excellent dosimetric material. We also present the good behavior of the CaSO4: Dy (0.1%) as a material for a retrospective dosimetry. (Author)

  13. Chemical-Looping Combustion and Gasification of Coals and Oxygen Carrier Development: A Brief Review

    Directory of Open Access Journals (Sweden)

    Ping Wang


    Full Text Available Chemical-looping technology is one of the promising CO2 capture technologies. It generates a CO2 enriched flue gas, which will greatly benefit CO2 capture, utilization or sequestration. Both chemical-looping combustion (CLC and chemical-looping gasification (CLG have the potential to be used to generate power, chemicals, and liquid fuels. Chemical-looping is an oxygen transporting process using oxygen carriers. Recently, attention has focused on solid fuels such as coal. Coal chemical-looping reactions are more complicated than gaseous fuels due to coal properties (like mineral matter and the complex reaction pathways involving solid fuels. The mineral matter/ash and sulfur in coal may affect the activity of oxygen carriers. Oxygen carriers are the key issue in chemical-looping processes. Thermogravimetric analysis (TGA has been widely used for the development of oxygen carriers (e.g., oxide reactivity. Two proposed processes for the CLC of solid fuels are in-situ Gasification Chemical-Looping Combustion (iG-CLC and Chemical-Looping with Oxygen Uncoupling (CLOU. The objectives of this review are to discuss various chemical-looping processes with coal, summarize TGA applications in oxygen carrier development, and outline the major challenges associated with coal chemical-looping in iG-CLC and CLOU.

  14. Methodology for the assessment of oxygen as an energy carrier (United States)

    Yang, Ming Wei

    Due to the energy intensity of the oxygen generating process, the electric power grid would benefit if the oxygen generating process was consumed electric power only during low demand periods. Thus, the question to be addressed in this study is whether oxygen production and/or usage can be modified to achieve energy storage and/or transmission objectives at lower cost. The specific benefit to grid would be a leveling, over time, of the demand profile and thus would require less installation capacity. In order to track the availability of electricity, a compressed air storage unit is installed between the cryogenic distillation section and the main air compressor of air separation unit. A profit maximizing scheme for sizing storage inventory and related equipments is developed. The optimum scheme is capable of market responsiveness. Profits of steel maker, oxy-combustion, and IGCC plants with storage facilities can be higher than those plants without storage facilities, especially, at high-price market. Price tracking feature of air storage integration will certainly increase profit margins of the plants. The integration may push oxy-combustion and integrated gasification combined cycle process into economic viability. Since oxygen is used in consumer sites, it may generate at remote locations and transport to the place needed. Energy losses and costs analysis of oxygen transportation is conducted for various applications. Energy consumptions of large capacity and long distance GOX and LOX pipelines are lower than small capacity pipelines. However, transportation losses and costs of GOX and LOX pipelines are still higher than electricity transmission.

  15. Oxygen Carriers for Chemical Looping Combustion - 4 000 h of Operational Experience

    International Nuclear Information System (INIS)

    Chemical Looping Combustion (CLC) is a new combustion technology with inherent separation of the greenhouse gas CO2. The technology involves the use of a metal oxide as an oxygen carrier which transfers oxygen from combustion air to the fuel, and hence a direct contact between air and fuel is avoided. Two interconnected fluidized beds, a fuel reactor and an air reactor, are used in the process. The outlet gas from the fuel reactor consists of CO2 and H2O, and the latter is easily removed by condensation. Considerable research has been conducted on CLC in the last years with respect to oxygen carrier development, reactor design, system efficiencies and prototype testing. Today, more than 700 materials have been tested and the technology has been successfully demonstrated in chemical looping combustors in the size range 0.3-140 kW, using different types of oxygen carriers based on oxides of the metals Ni, Co, Fe, Cu and Mn. The total time of operational experience is more than 4 000 hours. From these tests, it can be established that almost complete conversion of the fuel can be obtained and 100% CO2 capture is possible. Most work so far has been focused on gaseous fuels, but the direct application to solid fuels is also being studied. This paper presents an overview of operational experience with oxygen carriers in chemical looping combustors. (author)

  16. Feasibility study of CaSO4:Eu, CaSO4:Eu,Ag and CaSO4:Eu,Ag(NP) as thermoluminescent dosimeters

    International Nuclear Information System (INIS)

    This work evaluates the dosimetric properties of crystals of CaSO4 doped with unusual elements, such as europium (Eu) and silver (Ag), including their nanoparticle forms, after the incorporation of glass or Teflon and compares them with well-known thermoluminescent dosimeters (TLD). X-ray diffraction analyses showed that samples of doped CaSO4 exhibit only a single phase corresponding to the crystal structure of anhydrite. Optical spectroscopy confirmed the presence of Eu3+ in the crystal matrix and a luminescent gain due the presence of silver nanoparticles. The composites showed thermoluminescent emission glow curves, with a single peak centered at approximately 200 °C for pellets with Teflon and at 230 °C for pellets with glass. The dosimeters based on calcium sulfate doped with europium and silver nanoparticles provided the most intense thermoluminescent (TL) emission of the composites studied. In comparison with commercial TLD, such as LiF:Mg,Ti and CaSO4:Dy, the CaSO4:Eu,Ag(NP)+glass produced in this work presented similar low detection limits and higher sensitivity. The new methods for the preparation of dosimeters and the incorporation of glass are shown to be viable because all of the samples presented a linear, reproducible and first order kinetic TL emission. - Highlights: • Thermoluminescent properties of CaSO4 doped with Eu, Ag and Ag nanoparticles were evaluated. • Crystals were grown using a production route based in the Yamashita method. • Glass or Teflon was incorporate to the crystals in order to obtain composites. • The TL responses of the composites are proportional to the dose absorbed. • The CaSO4:Eu,Ag(NP) + glass has potential to be used as a thermoluminescent dosimeter

  17. Study of dimensional changes during redox cycling of oxygen carrier materials for chemical looping combustion

    NARCIS (Netherlands)

    Fossdal, A.; Darell, O.; Lambert, A.; Schols, E.; Comte, E.; Leenman, R.N.; Blom, R.


    Dimensional and phase changes of four candidate oxygen carrier materials for chemical looping combustion are investigated by dilatometry and high-temperature X-ray diffraction during four redox cycles. NiO/Ni2AlO4 does not exhibit significant dimensional changes during cycling, and it is shown that

  18. Regenerable MgO promoted metal oxide oxygen carriers for chemical looping combustion (United States)

    Siriwardane, Ranjani V.; Miller, Duane D.


    The disclosure provides an oxygen carrier comprised of a plurality of metal oxide particles in contact with a plurality of MgO promoter particles. The MgO promoter particles increase the reaction rate and oxygen utilization of the metal oxide when contacting with a gaseous hydrocarbon at a temperature greater than about C. The promoted oxide solid is generally comprised of less than about 25 wt. % MgO, and may be prepared by physical mixing, incipient wetness impregnation, or other methods known in the art. The oxygen carrier exhibits a crystalline structure of the metal oxide and a crystalline structure of MgO under XRD crystallography, and retains these crystalline structures over subsequent redox cycles. In an embodiment, the metal oxide is Fe.sub.2O.sub.3, and the gaseous hydrocarbon is comprised of methane.

  19. Methane combustion by moving bed fuel reactor with Fe2O3/Al2O3 oxygen carriers

    International Nuclear Information System (INIS)

    Highlights: • Moving bed reactor employed to methane combustion using iron-based oxygen carrier. • Fe2O3/Al2O3 oxygen carriers was prepared and provided with applicable performance. • Carbon formation was enhanced with increased retention time at 900 °C. • Full CH4 conversion was reached without carbon formation by moving bed operation. • FeO and FeAl2O4 were formed in the reacted oxygen carriers out of the reactor. - Abstract: Fe2O3/Al2O3 composite oxygen carriers were prepared for chemical looping combustion (CLC) with methane in a lab-scale moving bed fuel reactor provided with reasonable crush strength, reactivity and recyclability. Carbon formation was observed during the combustion process in the empty bed at 900 °C through methane decomposition reaction, and was enhanced for experiments conducted with increased retention time. Carbon formation was obviously reduced for experiments conducted in the moving bed fuel reactor with oxygen carrier-to-fuel ratio (ϕ) higher than 1.14. The oxygen carriers that moving out of the moving bed reactor were composed of mainly FeO and FeAl2O4, characterized by X-ray diffraction (XRD) analysis. The formation of FeO and FeAl2O4 indicated that further utilization of oxygen in iron-based oxygen carriers can be achieved by moving bed operation

  20. Artificial oxygen carriers--the new doping threat in endurance sport? (United States)

    Schumacher, Y O; Schmid, A; Dinkelmann, S; Berg, A; Northoff, H


    Maximal oxygen uptake is the major performance limiting factor in endurance sports. Sophisticated training methods have been developed to increase this variable. On the other hand, attempts have been made to improve maximal oxygen uptake by artificial means: blood doping and the misuse of recombinant human erythropoietin have beneficial effects on aerobic exercise capacity. Both methods have been banned by international sporting federations. A new class of substances might represent the next step of fraudulent improvement of the maximal oxygen uptake: artificial oxygen carriers, such as solutions based on recombinant, bovine or human hemoglobin and perfluorocarbon-emulsions have been shown to improve oxygen delivery to the muscle. Hemoglobin-based solutions improve aerobic exercise capacity in animal and human testing. Both substances have potentially lethal side effects including renal toxicity, increased systemic and pulmonary blood pressure and impairment of the immune system. Hemoglobin-based carriers can be detected in drug testing with routine laboratory tests based on the detection of free hemoglobin. Perfluorocarbon is not metabolized by the body and exhaled through the lung and can be measured with chromatography. No screening for these substances in drug tests has been performed so far. International sporting federations should be aware of this new, emerging doping threat. PMID:11719891



    Vásquez, Diana M.; Ortiz, Daniel; Alvarez, Oscar A.; Briceño, Juan C.; Cabrales, Pedro


    Perfluorocarbon (PFC) emulsion based oxygen carriers lack colloid osmotic pressure (COP) and must be administered with colloid-based plasma expanders (PEs). Although PFC emulsions have been widely studied, there is limited information about PFC emulsion interaction with PEs and blood. Their interaction forms aggregates due to electrostatic and rheological phenomena, and change blood rheology and blood flow. This study analyzes the effects of the interaction between PFC emulsions with blood in...

  2. A Study on CaSO4 Fouling Deposit

    Institute of Scientific and Technical Information of China (English)

    RenXiaoguang; LiCuiqing; LiuChanghou


    This paper reports the influences of heat transfer surface properties on the formation of CaSO4 fouling deposition during flow boiling heat transfer.The surfaces of several test heaters have been treated by surface modification techniques.such as dynamic mixing ion beam implantation and dynamic mixing magnetron sputtering to reduce surface energy.Fouling runs with these heaters were carried out at different heat fluxes,flow velocities and salt concentrations.The results show that heat transfer surfaces with low surface energy experienced significantly a reduced formation of CaSO4 deposit.

  3. Calcium and chemical looping technology for power generation and carbon dioxide (CO2) capture solid oxygen- and CO2-carriers

    CERN Document Server

    Fennell, Paul


    Calcium and Chemical Looping Technology for Power Generation and Carbon Dioxide (CO2) Capture reviews the fundamental principles, systems, oxygen carriers, and carbon dioxide carriers relevant to chemical looping and combustion. Chapters review the market development, economics, and deployment of these systems, also providing detailed information on the variety of materials and processes that will help to shape the future of CO2 capture ready power plants. Reviews the fundamental principles, systems, oxygen carriers, and carbon dioxide carriers relevant to calcium and chemical loopingProvi

  4. Development of an ultrasound sensitive oxygen carrier for oxygen delivery to hypoxic tissue. (United States)

    Eisenbrey, John R; Albala, Lorenzo; Kramer, Michael R; Daroshefski, Nick; Brown, David; Liu, Ji-Bin; Stanczak, Maria; O'Kane, Patrick; Forsberg, Flemming; Wheatley, Margaret A


    Radiation therapy is frequently used in the treatment of malignancies, but tumors are often more resistant than the surrounding normal tissue to radiation effects, because the tumor microenvironment is hypoxic. This manuscript details the fabrication and characterization of an ultrasound-sensitive, injectable oxygen microbubble platform (SE61O2) for overcoming tumor hypoxia. SE61O2 was fabricated by first sonicating a mixture of Span 60 and water-soluble vitamin E purged with perfluorocarbon gas. SE61O2 microbubbles were separated from the foam by flotation, then freeze dried under vacuum to remove all perfluorocarbon, and reconstituted with oxygen. Visually, SE61O2 microbubbles were smooth, spherical, with an average diameter of 3.1 μm and were reconstituted to a concentration of 6.5 E7 microbubbles/ml. Oxygen-filled SE61O2 provides 16.9 ± 1.0 dB of enhancement at a dose of 880 μl/l (5.7 E7 microbubbles/l) with a half-life under insonation of approximately 15 min. In in vitro release experiments, 2 ml of SE61O2 (1.3 E8 microbubbles) triggered with ultrasound was found to elevate oxygen partial pressures of 100ml of degassed saline 13.8 mmHg more than untriggered bubbles and 20.6 mmHg more than ultrasound triggered nitrogen-filled bubbles. In preliminary in vivo delivery experiments, triggered SE61O2 resulted in a 30.4 mmHg and 27.4 mmHg increase in oxygen partial pressures in two breast tumor mouse xenografts. PMID:25448552

  5. Validation of chemical-looping with oxygen uncoupling (CLOU using Cu-based oxygen carrier and comparative study of Cu, Mn and Co based oxygen carriers using ASPEN plus

    Directory of Open Access Journals (Sweden)

    Xiao Zhang, Subhodeep Banerjee, Ramesh K. Agarwal


    Full Text Available The chemical-looping with oxygen uncoupling (CLOU has been demonstrated to be an effective technological pathway for high-efficiency low-cost carbon dioxide capture when particulate coal serves as the fuel. In this paper, complete process-level modeling of CLOU process conducted in ASPEN Plus is presented. The heat content of fuel and air reactors and air/flue gas heat exchangers is carefully examined. It is shown that the established model provides results which are in excellent agreement with the experiments for the overall power output of the CLOU process. Finally the effect of varying the air flow rate and three different types of coal as the solid fuel on energy output is investigated, and the performance of three – Copper (Cu, Manganese (Mn and Cobalt (Co based oxygen carriers in CLOU process is compared. It is shown that there exists an optimal air flow rate to obtain the maximum power output for a given coal feeding rate and coal type. The effect of three different oxygen carriers on energy output is also investigated using the optimal air flow rate. Among the three oxygen carriers - CuO, Mn2O3, and Co3O4; Mn2O3 shows the best performance on power output. The results presented in this paper can be used to estimate the amount of various quantities such as the air flow rate and oxygen carrier (and its type required to achieve near optimal energy output from a CLOU process based power plant.

  6. Hemoglobin-Vesicles as Oxygen Carriers : Influence on Phagocytic Activity and Histopathological Changes in Reticuloendothelial System


    Sakai, Hiromi; Horinouchi, Hirohisa; Tomiyama, Kenichi; IKEDA, EIJI; Takeoka, Shinji; Kobayashi, Koichi; Tsuchida, Eishun


    Hemoglobin-vesicles (HbV) have been developed for use as artificial oxygen carriers (particle diameter, 250 nm) in which a purified Hb solution is encapsulated with a phospholipid bilayer membrane. The influence of HbV on the reticuloendothelial system was studied by carbon clearance measurements and histopathological examination. The HbV suspension ([Hb] = 10 g/dl) was intravenously infused in male Wistar rats at dose rates of 10 and 20 ml/kg, and the phagocytic activity was measured by moni...

  7. The Properties of CaSO4: Mn Thermoluminescence Dosimeters

    International Nuclear Information System (INIS)

    The properties of the radio thermoluminescence of CaSO4:Mn, used for dosimetry of gamma and roentgen radiation, have been investigated. The light yield of the luminophore has been determined to 1.5 percent for 1 MeV gamma radiation. The dependence of the thermoluminescence light sum on the exposure, the exposure rate, and the exposure time can qualitatively be described by the first order process model, modified by a broad energy distribution of the electron trap depths. Some applications are discussed. The cheapness of the dosimeters, the convenient read-out, and the broad range of measurable exposures suggest that CaSO4:Mn can be a valuable complement to other dosimetry systems

  8. Thermoluminescence mechanisms in CaSO4:Dy single crystals

    International Nuclear Information System (INIS)

    ESR studies of gamma-irradiated CaSO4:Dy have shown, in addition to the usual intrinsic defects, four new paramagnetic centres. An analysis of the g values and the g tensors in conjunction with the anhydrite crystal structure indicate that these centres are related to sulphate ions. Two of these centres (denoted 1a and 3a) are proposed as holes trapped and shared between two adjacent sulphate ions, this structure being stabilised by a neighbouring Ca vacancy. Centre 3b is suggested as a hole associated with one sulphate ion, again stabilised by an adjacent Ca vacancy. Because of the two distinct crystallographic directions in the anhydrite structure, centre 3b was found to consist of two distinguishable defects with slightly differing decay temperatures. The fourth centre appears to be an electron trapping site with structure similar to centre 3b. Decay temperatures of these ESR defects are correlated with the observance of TL peaks in CaSO4:Dy. Thermoluminescence studies as a function of impurity content confirmed the presence of calcium vacancies, which are formed during crystal growth, and that they play an important role in the TL process. TL models are proposed to account for the observed properties of CaSO4:Dy. (author)

  9. Physical properties of hemoglobin-poly(acrylamide) hydrogel-based oxygen carriers: effect of reaction pH. (United States)

    Patton, Jaqunda N; Palmer, Andre F


    This work examines the physical properties of bovine hemoglobin (BHb) chemically cross-linked to a pH responsive polymer (poly(acrylamide)) with the goal of taking advantage of the polymer's pH sensitivity to generate low-P50 oxygen carriers for application in physiological conditions characterized by deviations from normal pH. BHb-hydrogel-based oxygen carriers encapsulating 10-16 g/dL BHb displayed P50s liposomes (i.e. Hb-LGs) and change conformations between the R and T states. The magnitude of the zeta potential of Hb-LGs and Hb-NHPs was shown to be within the range of stored red blood cells and within the range of limited flocculation. Taken together, this work describes the preparation and characterization of oxygen carriers with increased oxygen affinities compared to those of red blood cells. PMID:16489809

  10. Effect of oxygen precipitates in solar grade silicon on minority carrier lifetime and efficiency of solar cells

    Institute of Scientific and Technical Information of China (English)

    SUN Haizhi; LIU Caichi; HAO Qiuyan; WANG Lijian


    The effect of oxygen precipitates on minority carrier lifetime and performance of solar cell was studied by means of Fourier Transform Infrared Spectroscopy (FTIR), quasi-steady state photoconductance (QSSPCD), optical microscope, spectrumresponse and solar cell efficiency test. The minority carrier lifetime and performance of solar cell reduced depend on oxygen precipitates. A few of oxygen precipitates have formed after single-step annealing; and they do not impact the efficiency dramatically. Pre-annealing at 650 ℃ for 4 h enhances the oxygen precipitation when it is subjected to middle temperature annealing. The solar cells performance decayed sharply. Especially annealing at 950 ℃ for 3 h, the V os and I sc of cells decrease 12% and 25% respectively. Few oxygen precipitates have formed in silicon after high temperature annealing at about 1050 ℃ whether pre-annealing is used or not, and the performance of cells is notbe affected.

  11. High dose and phototransferred thermoluminescence in CaSO4, CaSO4:Dy, and CaSO4:Tm

    International Nuclear Information System (INIS)

    An investigation is presented to test the feasibility of extending the usefulness of the CaSO4 phosphor doped with Tm or Dy into the high dose/high temperature regime. The doses studied range from 1 kGy to 100 kGy obtained from γ ray and flash electron beam sources. Integrated glow curve signals in the 'dosimetry range' (∼100-350oC) and the high temperature range (∼350-600oC) are measured as a function of dose. Integrated UV phototransferred thermoluminescence signals (∼100-300oC) are similarly considered. For powdered samples doped to 0.1 mol%, the onset of saturation occurs near 10 kGy. This establishes that thermoluminescence doseimetry for industrial food processing (pasteurisation, disinfestation, radicidation and radurisation) is a possibility.( (author)

  12. Performance of coal fly-ash based oxygen carrier for the chemical looping combustion of synthesis gas

    International Nuclear Information System (INIS)

    Highlights: • Fly-ash based oxygen carriers were synthesised for chemical looping combustion of synthesis gas. • Using fly-ash as the support of the oxygen carrier enhanced the thermal stability and oxidant transfer for fuel oxidation. • Fly-ash based nickel oxide reformed hydrocarbons into carbon monoxide with the presence of carbon dioxide. - Abstract: The performance of coal fly-ash based oxygen carriers for chemical looping combustion of synthesis gas has been investigated using both a thermogravimetric analyser and a packed bed reactor. Oxygen carriers with 50 wt% active metal compounds, including copper, nickel and iron oxides, supported on coal fly-ash were synthesised using the deposition–precipitation method. Copper oxide and nickel oxide supported on fly-ash showed high oxygen transfer efficiency and oxygen carrying capacity at 800 °C. The fly-ash based nickel oxide was effective in reforming hydrocarbons and for the conversion of carbon dioxide into carbon monoxide; a nickel complex with silicate was identified as a minor phase following the reduction reaction. The fly-ash based iron oxide showed various reduction steps and resulted in an extended reduction time. The carbon emission at the oxidation stage was avoided by reducing the length of the exposure to the reduction gas

  13. The use of ilmenite as oxygen carrier with kerosene in a 300 W CLC laboratory reactor with continuous circulation

    International Nuclear Information System (INIS)

    Graphical abstract: Experiments with sulfur-free and sulfurous kerosene were performed using ilmenite oxygen carrier. Fuel conversion improved significantly and lasting when sulfurous kerosene was used. - Highlights: • Experiments were performed in a 300 W reactor with continuous circulation. • Sulfurous and sulfur-free kerosene were used directly as fuel. • Ilmenite oxygen carrier (Norwegian rock ilmenite) was tested. • Combustion experiments were performed for 50 h (sulfur-free) and 30 h (sulphurous), respectively. • A significant and lasting improvement in the oxygen carrier’s reactivity was achieved by using sulfurous kerosene. - Abstract: An ilmenite oxygen carrier was tested in a laboratory scale chemical-looping reactor with a nominal thermal capacity of 300 Wth. Ilmenite is a mineral iron–titanium oxide, which has been used extensively as an oxygen carrier in chemical-looping combustion. Two different kinds of fuels were used, a sulfur-free kerosene and one kerosene that contained 0.57 mass% sulfur. Both fuels were continuously evaporated and directly fed into the chemical-looping reactor. Experiments were conducted for 50 h with the sulfur-free kerosene and for 30 h with the sulfurous kerosene. CO2 yields above 99% were achieved with both types of fuel. A significant and lasting improvement in the oxygen carrier’s reactivity was observed, presumably an effect of using sulfurous kerosene. No evidence of sulfur was found on the particles’ surface

  14. Simulation of oxygen carrier mediated oxygen transport to C3A hepatoma cells housed within a hollow fiber bioreactor. (United States)

    Sullivan, Jesse P; Gordon, Jason E; Palmer, Andre F


    A priori knowledge of the dissolved oxygen (O2) concentration profile within a hepatic hollow fiber (HF) bioreactor is important in developing an effective bioartificial liver assist device (BLAD). O2 provision is limiting within HF bioreactors and we hypothesize that supplementing a hepatic HF bioreactor's circulating media with bovine red blood cells (bRBCs), which function as an O2 carrier, will improve oxygenation. The dissolved O2 concentration profile within a single HF (lumen, membrane, and representative extra capillary space (ECS)) was modeled with the finite element method, and compared to experimentally measured data obtained on an actual HF bioreactor with the same dimensions housing C3A hepatoma cells. Our results (experimental and modeling) indicate bRBC supplementation of the circulating media leads to an increase in O2 consumed by C3A cells. Under certain experimental conditions (pO2,IN) = 95 mmHg, Q = 8.30 mL/min), the addition of bRBCs at 5% of the average in vivo human red blood cell concentration (% hRBC) results in approximately 50% increase in the O2 consumption rate (OCR). By simply adjusting the operating conditions (pO2,IN) = 25 mmHg, Q = 1.77 mL/min) and increasing bRBC concentration to 25% hRBC the OCR increase is approximately 10-fold. However, the improved O2 concentration profile experienced by the C3A cells could not duplicate the full range of in vivo O2 tensions (25-70 mmHg) typically experienced within the liver sinusoid with this particular HF bioreactor. Nonetheless, we demonstrate that the O2 transport model accurately predicts O2 consumption within a HF bioreactor, thus setting up the modeling framework for improving the design of future hepatic HF bioreactors. PMID:16161160

  15. Molecular Design Properties of OxyVita Hemoglobin, a New Generation Therapeutic Oxygen Carrier: A Review

    Directory of Open Access Journals (Sweden)

    Hanna Wollocko


    Full Text Available OxyVita Hb is a new generation hemoglobin based oxygen carrier (HBOC produced through modification of a zero-linked polymerization mechanism using activators which incorporate cross-linked bovine tetramer hemoglobin into “super-polymeric” macromolecules (Average molecular weight = 17 MDa for the purpose of oxygen delivery when whole blood or packed red cells are not available. This molecular design approach was generated in order to address several fundamental biochemical and physiological weaknesses of previous generations of HBOCs. Observation during pre-clinical and clinical studies provided evidence that these early generation acellular HBOCs were directly associated with loss of retention within the circulatory system, extravasation across endothelial tissue membranes due to their small molecular size leading to arterial and venous vasoconstriction with coupled increases in mean arterial pressure (MAP. The inherent increase in molecular size and structural stability of the OxyVita Hb is a direct response to addressing these serious weaknesses that have occurred during the evolution of HBOC development within the past two decades. The nature of the zero-linked synthetic route eliminates any chemical linkers remaining in the product, eliminating side reaction concerns, such as reversibility and decomposition due to weak chemical bonds, dependency on temperature and pressure, and residual toxicity.

  16. [Effects of Hydraulic Retention Time and Dissolved Oxygen on a CANON Reactor with Haydite as Carrier]. (United States)

    Wang, Hui-fang; Fu, Kun-ming; Zuo, Zao-rong; Qiu, Fu-guo


    One Completely Autotrophic Nitrogen Removal Over Nitrite ( CANON) reactor with haydite as carrier was investigated to study the effects of different hydraulic retention time ( HRT) and dissolved oxygen (DO) on CANON reactors by seeding sludge from another mature CANON reactor and using synthetic inorganic ammonia-rich waste water as influent. During the experiment, the concentration of influent ammonia nitrogen was basically unchanged, the HRT of the reactor were 9, 7, 5 h in turn and the range of DO was 1.16-3.20 mg x L(-1). The results showed that: (1) When DO was 1.20-1.75 mg x L(-1), despite the increase of DO can improve AOB's activity and matrix mass transfer in the system, NH4(+) -N and TN removal efficiency were still fell with the shortening of HRT for the CANON reactor, especially when DO was higher than 2.50 mg x L(-1), TN removal efficiency dropped sharply; (2) Under the condition that DO was 1.20-1.75 mg x L(-1), with the shortening of HRT, partial nitritation tended to be stable in the CANON process, and when DO was higher than 1.75 mg x L(-1), even if HRT was shorter, partial nitritation was still severely damaged; (3) Under the condition that DO was 1.20-1.75 mg x L(-1) and HRT was 7 h, for the CANON reactor, partial nitritation and total nitrogen removal efficiency kept well. Hydraulic retention time and dissolved oxygen both are important operational parameters for biological wastewater treatment process, which could directly affect the effect of biological treatment and effluent quality, so to choose appropriate hydraulic retention time and dissolved oxygen coordinately is very important to improve the effect of treatment of ammonium-rich wastewater by CANON process. PMID:26911004

  17. Identification of deep trap energies and influences of oxygen plasma ashing on semiconductor carrier lifetime (United States)

    Koprowski, A.; Humbel, O.; Plappert, M.; Krenn, H.


    We have performed an analytical study of the effects of oxygen plasma ashing processes in semiconductor device fabrication and its impact on minority carrier lifetime in high voltage semiconductor devices. Our work includes a critical background study of life time killing mechanisms by deep traps imparted into the semiconductor by barrel plasma ashing. The Elymat technique provides the opportunity to measure lifetime and diffusion length of minority carriers and surface photo voltage (SPV) measurement was used to analyse influences of process parameters such as photoresist, time budget and positioning in the process chamber. It was shown that in microwave plasma processes the diffusion length changes severely with tempering at 200 °C, whereas RF-plasma processes show a significant process time-dependence. Batch tools in general suffer from a strong first wafer effect which could be correlated with the static electrical parameters of the semiconductor devices. The trap identities were detected by using deep level transient spectroscopy and the chemical species of the traps has been proven by inductive coupled plasma mass spectrometry. The deep-bandgap trap energies are reliable fingerprints of the chosen process parameters such as process time and of resist-influences. By microwave plasma processes intrinsic Fe and FeB-complex levels were identified and a good agreement with the SPV-measurement and electrical device characteristic was shown. RF-plasma processes impart levels attributed to Pt levels and an additional level, which could be identified as a trap level probably forming a complex of Pt and H.

  18. Identification of deep trap energies and influences of oxygen plasma ashing on semiconductor carrier lifetime

    International Nuclear Information System (INIS)

    We have performed an analytical study of the effects of oxygen plasma ashing processes in semiconductor device fabrication and its impact on minority carrier lifetime in high voltage semiconductor devices. Our work includes a critical background study of life time killing mechanisms by deep traps imparted into the semiconductor by barrel plasma ashing. The Elymat technique provides the opportunity to measure lifetime and diffusion length of minority carriers and surface photo voltage (SPV) measurement was used to analyse influences of process parameters such as photoresist, time budget and positioning in the process chamber. It was shown that in microwave plasma processes the diffusion length changes severely with tempering at 200 °C, whereas RF-plasma processes show a significant process time-dependence. Batch tools in general suffer from a strong first wafer effect which could be correlated with the static electrical parameters of the semiconductor devices. The trap identities were detected by using deep level transient spectroscopy and the chemical species of the traps has been proven by inductive coupled plasma mass spectrometry. The deep-bandgap trap energies are reliable fingerprints of the chosen process parameters such as process time and of resist-influences. By microwave plasma processes intrinsic Fe and FeB-complex levels were identified and a good agreement with the SPV-measurement and electrical device characteristic was shown. RF-plasma processes impart levels attributed to Pt levels and an additional level, which could be identified as a trap level probably forming a complex of Pt and H. (paper)

  19. Atomistic modelling of the hydration of CaSO 4 (United States)

    Adam, Craig D.


    Atomistic modelling techniques, using empirical potentials, have been used to simulate a range of structures formed by the hydration of γ-CaSO 4 and described as CaSO 4· nH 2O (0commercial importance and has been subjected to much experimental study. These simulation studies demonstrate significant water-matrix interactions that influence the crystallography of the hydrated phase. The existence of two types of hydration site has been predicted, including one within the Ca 2+coordination sphere. Close correlation between water molecule bonding energy, Ca 2+-O w bond length and unit-cell volume have been established. This shows that as the number of water molecules within the unit cell increases, the bonding energy increases and the unit cell contracts. However around n=0.5, this process reaches a turning point with the incorporation of further waters resulting in reduced binding energy and an expanding unit cell.

  20. Influence of oxygen addition to the carrier gas on laser-induced breakdown spectroscopy measurements on aerosols (United States)

    Palazzo, N.; Migliorini, F.; Dondè, R.; Maffi, S.; De Iuliis, S.


    In this work, laser-induced breakdown spectrosopy is implemented on aerosol particles for absolute concentration analysis. The aim of this work is the investigation of the effect of the bath gas used for nebulizing the aerosol. Nitrogen, air, and 50% O2 in N2 mixture have been chosen as carrier gasses in order to analyze the effect of oxygen addition to the gas. LIBS measurements have been carried out on aerosol particles produced from CuCl2 2H2O solutions, and the 324.7 nm Cu line is considered. As a first analysis, plasma parameters, such as temperature and electron density, have been evaluated changing the carrier gas. Measurements to derive the LIBS calibration curve of the 324.7 nm Cu line are carried out in air and in N2. The significant difference in the slope of the resulting calibration curves has to be attributed to the oxygen addition to the bath gas. To explore such behavior, time-resolved measurements of the Cu line and peak/base ratio have been performed. The presence of two competitive effects have been observed that becomes significant increasing the amount of oxygen in the carrier gas. One is the oxygen-quenching effect, already observed in the literature, and the other one is the enhancement of the Cu LIBS signal, expecially at short delay times. These effects have been observed also at other Cu lines and changing the analyte source. The results are presented and widely discussed.

  1. Luminescent characteristics of CaSO4:Dy films obtained by spray pyrolysis method

    International Nuclear Information System (INIS)

    The present paper reports the experimental results of dysprosium doped calcium sulphate (CaSO4:Dy) films deposited by spray pyrolysis method. CaSO4:Dy films were deposited on three different surfaces: glass, aluminum and quartz substrates at temperatures in the range from 450 to 600 °C. Structural and morphological characteristics of CaSO4:Dy films were observed. Thermoluminescent characteristics of films were determined by irradiating ultraviolet energy region. Thermoluminescent glow curve of CaSO4:Dy films with glass and aluminum substrates showed a peak under environmental irradiation. Both TL response glow shape and intensity of CaSO4:Dy films UV irradiated as a function of substrates were studied. - Highlights: ► We carried out the preparation of calcium sulfate films doped with dysprosium (CaSO4:Dy) by spray paralysis method. ► SEM and EDS techniques were applied to study the surface topography and chemical composition of the CaSO4:Dy films. ► Thermoluminescent characteristics of films were determined by irradiating ultraviolet energy region. ► The thermoluminescent response of CaSO4:Dy films as a function of substrate was analyzed.

  2. Performance of Brazilian thermoluminescent CaSO4: Dy pellets in standard diagnostic radiology beams

    International Nuclear Information System (INIS)

    The high sensitivity of CaSO4: Dy as a thermoluminescent material is a great advantage when dealing with low dose levels, as in diagnostic radiology procedures. However, these kinds of dosemeters present a high energy dependence that must be precisely determined in the energy range of interest. Dosimetric pellets of CaSO4: Dy are produced at IPEN since the end of the 80 Th decade. These pellets are produced in three forms: conventional CaSO4: Dy (50 mg); thin CaSO4: Dy (20 mg) and CaSO4: Dy + 10% C (20 mg). The main applications of these dosemeters are in personal and environmental dosimetry. In this study, CaSO4: Dy pellets produced at IPEN were evaluated in diagnostic radiology standard beams. These qualities are based on the IEC 61267 standard, and they were established at an industrial X-ray system Pantak/Seifert, model ISOVOLT 160HS. Former studies evaluated CaSO4: Dy of different origins in diagnostic beams. In this study, a large energy interval was used to include computed tomography energy beams. The results obtained show the behavior of the IPEN CaSO4: Dy pellets in diagnostic standard beams. All results confirm that these pellets may be used for dosimetric procedures in diagnostic radiology beams. (Author)

  3. A review of blood substitutes: examining the history, clinical trial results, and ethics of hemoglobin-based oxygen carriers


    Jiin-Yu Chen; Michelle Scerbo; George Kramer


    The complications associated with acquiring and storing whole blood for transfusions have launched substantial efforts to develop a blood substitute. The history of these efforts involves a complicated mixture of science, ethics, and business. This review focuses on clinical trials of the three hemoglobin-based oxygen carriers (HBOC) that have progressed to Phase II or III clinical trials: He-mAssist (Baxter; Deerfield, IL, US), PolyHeme (Northfield; Evanston, IL, US), and Hemopure (Biopure; ...

  4. Energy response of CaSO4:Dy teflon TLD disk dosimeters to photons and electrons. (United States)

    Sharada, K S


    The photon energy response of CaSO4:Dy teflon disk dosimeters used widely in radiation dosimetry is computed using the energy absorption coefficient values for calcium, sulfur, oxygen, and carbon taken from J. H. Hubbell's tables. For fluorine, the energy absorption coefficients were obtained from the values given by F. H. Attix for CaF2 and Ca. The energy response of the radiation-monitoring disk for the range of 10 keV to 10 MeV, relative to air, is computed and plotted. The response is maximum between 20 and 30 keV and then gradually falls to a constant at 200 keV to 10 MeV. This computed response for different energies is compared with the experimental TL response of the dosimeter. The electron energy response of these TLD disks is computed using the stopping-power values for the different component elements. The electron stopping power for sulfur and calcium from 10 keV to 10 MeV is computed using the Bethe-Bloch formula. Those for oxygen and carbon are taken from the tables given by M. J. Berger and S. M. Seltzer. For fluorine, the values are computed from those for Li and LiF given in the same tables. This calculated response is compared with the experimental beta response of the TL dosimeter. PMID:6823508

  5. Enhanced Photoexcited Carrier Separation in Oxygen-Doped ZnIn2 S4 Nanosheets for Hydrogen Evolution. (United States)

    Yang, Wenlong; Zhang, Lei; Xie, Junfeng; Zhang, Xiaodong; Liu, Qinghua; Yao, Tao; Wei, Shiqiang; Zhang, Qun; Xie, Yi


    Limited by the relatively sluggish charge-carrier separation in semiconductors, the photocatalytic performance is still far below what is expected. Herein, a model of ZnIn2 S4 (ZIS) nanosheets with oxygen doping is put forward to obtain in-depth understanding of the role that doping atoms play in photocatalysis. It shows enhanced photocatalytic activity compared with pristine ZIS. The electron dynamics analyzed by ultrafast transient absorption spectroscopy reveals that the average recovery lifetime of photoexcited electrons is increased by 1.53 times upon oxygen incorporation into the ZIS crystals, indicating enhanced separation of photoexcited carriers in oxygen-doped ZIS nanosheets. As expected, the oxygen-doped ZIS nanosheets show a remarkably improved photocatalytic activity with a hydrogen evolution rate of up to 2120 μmol h(-1)  g(-1) under visible-light irradiation, which is 4.5 times higher than that of the pristine ZIS nanosheets. PMID:27100950

  6. EPR-TL correlation studies on Bi co-doped CaSO4:Dy phosphor

    International Nuclear Information System (INIS)

    CaSO4:Dy, CaSO4:(Dy, Bi) and CaSO4:Bi phosphors were prepared through re-crystallization method. Thermoluminescence (TL) characteristics of these phosphor samples were investigated. The radiation induced radical ions formed in these phosphors were investigated using electron paramagnetic resonance (EPR) spectroscopy. The main signals observed in both CaSO4:(Dy, Bi) and CaSO4:Bi were identified as SO4- (II), SO4- (-perpendicular ) and SO3- (isotropic) with 'g' values 2.023, 2.0089 and 2.004, respectively. In order to understand the TL mechanism, CaSO4:(Dy, Bi) phosphor samples were annealed between 100 and 250 oC and their EPR spectra were studied. It was observed that EPR signal intensities reduce drastically in 250 oC annealed phosphor confirming the role of SO4- and SO3- types of defect centers in the dosimetric peak. The reduction in the TL sensitivity with increase in Bi3+ co-dopant in the phosphor samples was correlated with quenching of TL by Bi3+ ions rather than the reduction in the concentration of the above defect centers. An effort was also made to use the Bi3+ co-doped CaSO4:Dy phosphor for dosimetry of chilled or frozen food irradiation.

  7. Enhanced growth and recombinant protein production of Escherichia coli by a perfluorinated oxygen carrier in miniaturized fed-batch cultures

    Directory of Open Access Journals (Sweden)

    Neubauer Peter


    Full Text Available Abstract Background Liquid perfluorochemicals (PFCs are interesting oxygen carriers in medicine and biotechnology with a high solubility for oxygen. They have been repeatedly used for improving oxygen transfer into prokaryotic and eukaryotic cell cultures, however their application is still limited. Here we show the great benefit of air/oxygen saturated perfluorodecalin (PFD for high cell density cultivation of Escherichia coli in microwell plates and their positive effect on the soluble production of a correctly folded heterologously expressed alcohol dehydrogenase. Results In EnBase® cultivations the best effect was seen with PFD saturated with oxygen enriched air (appr. 10 μM oxygen per ml when PFD was added at the time of induction. In contrast the effect of PFD was negligible when it was added already at the time of inoculation. Optimisation of addition time and content of loaded oxygen into the PFD resulted in an increased the cell density by 40% compared to control cultures, and correspondingly also the product yield increased, demonstrated at the example of a recombinant alcohol dehydrogenase. Conclusions PFCs are a valuable additive in miniaturized cell culture formats. For production of recombinant proteins in low cell density shaken cultures the addition of oxygen-enriched PFD makes the process more robust, i.e. a high product yield is not any more limited to a very narrow cell density window during which the induction has to be done. The positive effect of PFD was even more obvious when it was added during high cell density cultures. The effect of the PFD phase depends on the amount of oxygen which is loaded into the PFD and which thus is a matter of optimisation.

  8. Production of CaSO4:Dy thermoluminescence dosimeters from natural crystals of Iran

    International Nuclear Information System (INIS)

    Calcium sulphate (CaSO4:Dy) thermoluminescence (TL) phosphors were produced from natural CaSO4:2H2O crystals of Iran for large-scale dosimetry. The procedure of recrystallization of the natural crystals was followed. A known amount of Dy2O3 was added into diluted H2SO4 as dopant at 200 degree C. Also a known amount of CaSO4:2H2O powder was added to the solution heated up to final recrystallization stage. Different parameters such as washing of the crystal powder for sodium (Na) removal, Dy2O3 incorporation and oven-heating temperature were optimized. The TLD phosphor produced has a sensitivity over 1.3 times higher than that of Harshaw CaSO4:Dy phosphors. The results are presented and discussed. (7 figs.)

  9. Thermoluminescent properties of CaSO4:Dy prepared by precipitation method

    International Nuclear Information System (INIS)

    This paper reports the synthesis and thermoluminescent (Tl) characterization of CaSO4:Dy obtained by the precipitation method. Thermoluminescent CaSO4:Dy powder and Teflon (PTFE) were mixed in order to obtain samples in pellets form. Samples of CaSO4:Dy were exposed to a radiation gamma source of 60Co and 90Sr beta particles. Tl response of CaSO4:Dy showed a glow curve with two peaks centered at around 164 and 302 C. Tl phosphor showed a good linearity in the range from 0.5 to 30 Gy. Fading of the Tl information was 5.19 % in 37 days and presented a standard deviation of 4% for reproducibility. (Author)

  10. Thermoluminescent analysis of CaSO4 composites activated with rare earths

    International Nuclear Information System (INIS)

    Since the thermoluminescence started to be applied to the dosimetry of ionizing radiation in 1940 different materials detectors have been proposed, and one of the most common is CaSO4. The motivation of this work was to produce crystals of CaSO4 doped with rare earth elements such as europium (Eu), neodymium (Nd) and thulium (Tm). It was also produced crystals of CaSO4:Ag. The interest in the production of these materials was to investigate other methods of production of thermoluminescent materials. The results show that the CaSO4:Tm is more suitable for use in the thermoluminescent dosimetry. Although not the most intense peak, the peak at 170 °C could be a dosimetric peak. Analyses showed that all samples have a TL response proportional to the dose absorbed. (author)

  11. Preparation of CaSO4:Dy by precipitation method to gamma radiation dosimetry

    International Nuclear Information System (INIS)

    This paper presents the results of the preparation and characterization of dysprosium-doped calcium sulfate (CaSO4:Dy) phosphor, which was obtained by homogeneous precipitation from calcium acetate Ca(CH3COO-)2. Structural and morphological characteristics were studied using a scanning electronic microscope (SEM). The structure of all compounds was determined by X-ray diffraction method too. Thermoluminescence (TL) emission properties of CaSO4:Dy under gamma radiation effects were studied. This phosphor powder presented a TL glow curve with two peaks (Tmax) centered at around of 180 and 300 deg. C, respectively. The TL response of CaSO4:Dy as a function of gamma absorbed dose was linear in a wide range. Both emission and excitation spectra were also obtained. Results showed that this new preparation method of CaSO4:Dy TL phosphor is less expensive, cleaner and safer than the conventional preparation method.

  12. Syngas combustion in a 500 Wth Chemical-looping combustion system using an impregnated Cu-based oxygen carrier


    Forero, C.R.; Gayán Sanz, Pilar; Diego Poza, Luis F. de; Abad Secades, Alberto; García Labiano, Francisco; Adánez Elorza, Juan


    Chemical-Looping Combustion (CLC) is an emerging technology for CO2 capture because separation of this gas from the other flue gas components is inherently to the process and thus no energy is expended for the separation. For its use with coal as fuel in power plants, a process integrated by coal gasification and CLC would have important advantages for CO2 capture. This paper presents the combustion results obtained with a Cu-based oxygen carrier in a continuous operation CLC p...

  13. Soluble minerals in chemical evolution. I - Adsorption of 5-prime-AMP on CaSO4 - A model system (United States)

    Orenberg, J. B.; Chan, S.; Calderon, J.; Lahav, N.


    The adsorption of 5-prime-AMP onto solid CaSO4-2H2O was studied in a saturated suspension as a function of pH and electrolyte concentration. The adsorption is pH-dependent and is directly correlated with the charge on the 5-prime-AMP molecule which is determined by the state of protonation of the N-1 nitrogen of the purine ring and the phosphate oxygens. It is proposed that the binding that occurs between the nucleotide and the salt is electrostatic in nature. The adsorption decreases with increasing ionic strength of the solution which means that in a fluctuating environment of wetting and drying cycles, a biomolecule similar to 5-prime-AMP could be expected to desorb during the drying phase. The results indicate that CaSO4-2H2O can serve as a concentrating surface for biomolecules. The significance of this is discussed with regard to the possible role of soluble minerals and their surfaces in a geochemical model consistent with the evolution of the earth and the origin of life.

  14. Development of Li compound embedded with CaSO4:Dy TL pellet for neutron measurement

    International Nuclear Information System (INIS)

    Personal neutron dosimetry is quite a difficult area because a neutron is always accompanied with gamma radiation, which is required of a the capability for mixed field dosimetry. CaSO4: Dy phosphor is known to have a very high sensitivity to gamma, but the neutron capture cross section of the constituents of CaSO4:Dy are so small that the interactions between the thermal neutron and the phosphor are rare. One method to improve the neutron interaction is by introducing an impurity ion with a large thermal neutron captures cross section into the phosphor to act as a neutron target centre such as 6Li. In neutron-gamma mixed radiation fields, if two detectors for the 6Li-7Li compounds embedded CaSO4:Dy TL pellets are used, a 6Li-compound embedded pellet can detect the neutron and gamma radiation together, and the other pellet can only detect the gamma radiation. Recently Korea Atomic Energy Research Institute (KEARI) has developed a new type of CaSO4:Dy TL materials embedded with phosphorous (KCT-300) to detect beta and gamma radiation with a very high sensitivity. This paper presents the development of CaSO4:Dy TL pellets embedded with 6Li compound for a thermal neutron measurement, and the detection method of the neutron and gamma dose in mixed fields with CaSO4:Dy TL pellets embedded with a 6Li compound(KCT-306) and CaSO4:Dy TL pellets embedded with a 7Li compound(KCT-307) is introduced. The net neutron sensitivity of CaSO4:Dy TL pellets embedded with 6Li compound developed in this study is about 2 times higher than that of the TLD-600 (Harshaw Co.) dosimeter which is available in the open market

  15. Feasibility study of CaSO4:Tb,Yb as a thermoluminescent dosimeter

    International Nuclear Information System (INIS)

    A new composite based on CaSO4, using terbium as dopant and ytterbium as co-dopant (CaSO4:Tb,Yb), was developed for employment as a thermoluminescent (TL) dosimeter. The crystals used in this work were grown using a production route based on the Yamashita method (Yamashita et al., 1968). Crystal powder was calcined at 600 °C for 1 h. Pellets were made by adding commercial and colorless glass to improve physical resistance and sintered at 700 °C for 6 h. All samples were irradiated by a beta source (90Sr/90Y) and received doses from 1 Gy to 5 Gy. TL analyses have been performed and characteristics such as sensitivity, reproducibility, linearity, and fading have been studied. The CaSO4:Tb,Yb pellets glow curves presented two peaks, the first at around 115 °C, and the second at around 200 °C. The highest intensity was shown for CaSO4:Tb,Yb with a concentration of 0.1 mol% of Tb and Yb together. In all the samples the TL response was proportional to the absorbed dose. Therefore, the CaSO4:Tb,Yb has potential to be used as a thermoluminescent dosimeter. - Highlights: ► A new dosimeter based on CaSO4 and doped with Tb and Yb is proposed. ► The samples were grown using a production route based in the Yamashita method. ► CaSO4:Tb,Yb glow curves exhibited a TL emission in temperatures from 100 to 270 °C. ► The TL responses of the composites produced are proportional to the dose absorbed. ► The CaSO4:Tb,Yb has potential to be used as a thermoluminescent dosimeter

  16. Thermoluminescent response of CaSO4:Dy+PTFE induced by X-ray beams

    International Nuclear Information System (INIS)

    The aim of the present work was to evaluate the feasibility of the utilization of CaSO4:Dy pellets for X-ray measurements in a general radiology department. Thermoluminescence (TL) response of CaSO4:Dy+PTFE was compared to the TL response of commercial LiF:Mg,Ti (TLD-100) samples. TL pellets were exposed to X-ray beam from X-ray machine CMR for clinical diagnosis purpose. The calibration curve of CaSO4:Dy+PTFE was obtained and it showed a linear response as a function of absorbed dose in air at the studied dose interval. Despite this fact, this material can be used for X-ray beams measurements if appropriate calibration procedures are performed. - Highlights: ► Developing of CaSO4:Dy to quasimono-energetic X-ray low energy dosimetry. ► Thermoluminescent response of caSO4:Dy to X-ray low dose. ► TL characteristics of CaSO4:Dy for X-ray beam quality control.

  17. Preparation, characterization and in vivo investigation of blood-compatible hemoglobin-loaded nanoparticles as oxygen carriers. (United States)

    Lu, Mingzi; Zhao, Caiyan; Wang, Quan; You, Guoxing; Wang, Ying; Deng, Hongzhang; Chen, Gan; Xia, Sha; Zhao, Jingxiang; Wang, Bo; Li, Xianlei; Shao, Leihou; Wu, Yan; Zhao, Lian; Zhou, Hong


    Although many attempts have been made to design advanced hemoglobin-based oxygen carriers (HBOCs), no clinically viable product has been widely approved, because they do not perform normal blood functions, such as coagulation, hematologic reactions and stability. Additionally, the in vivo oxygenation of hemoglobin-loaded nanoparticles (HbPs) encapsulated with polymers has seldom been proved. Herein, HbPs of approximately 200nm with good stability were successfully fabricated and exhibited oxygen-carrying capacity. The HbPs preserve the biological and structure features of hemoglobin according to UV-vis spectrophotometry, Fourier transform infrared (FTIR) spectroscopy and circular dichroism (CD) spectral analysis. In vitro, the HbPs showed a viscosity comparable to that of blood with no obvious effects on red blood cell aggregation. At the same time, blood compatibility was characterized in terms of platelet function, clot strength, speed of clot formation, degree of fibrin cross-linking and hemolysis rate. After intravenous administration of HbPs to mice with controlled hemorrhages, blood flow recovery and maintenance of systemic oxygenation were observed. PMID:26708138

  18. Screening of NiFe2O4 Nanoparticles as Oxygen Carrier in Chemical Looping Hydrogen Production

    DEFF Research Database (Denmark)

    Liu, Shuai; He, Fang; Huang, Zhen;


    ) porosity test. The performance of the prepared materials was first evaluated in a TGA reactor through a CO reduction and subsequent steam oxidation process. Then a complete redox process was conducted in a fixed-bed reactor, where the NiFe2O4 oxygen carrier was first reduced by simulated biomass pyrolysis...... gas (24% H2 + 24% CO + 12% CO2 + N2 balance), then reacted with steam to produce H2, and finally fully oxidized by air. The NiFe2O4 oxygen carrier prepared by the sol gel method showed the best capacity for hydrogen production and the highest recovery degree of lattice oxygen, in agreement with the......The objective of this paper is to systematically investigate the influences of different preparation methods on the properties of NiFe2O4 nanoparticles as oxygen carrier in chemical looping hydrogen production (CLH). The solid state (SS), coprecipitation (CP), hydrothermal (HT), and sol-gel (SG...

  19. Chemical-looping gasification of biomass in a 10k Wth interconnected fluidized bed reactor using Fe2 O3/Al2 O3 oxygen carrier

    Institute of Scientific and Technical Information of China (English)

    HUSEYIN Sozen; WEI Guo-qiang; LI Hai-bin; HE Fang; HUANG Zhen


    The aim of this research is to design and operate a 10 kW hot chemical-looping gasification ( CLG) unit using Fe2 O3/Al2 O3 as an oxygen carrier and saw dust as a fuel. The effect of the operation temperature on gas composition in the air reactor and the fuel reactor, and the carbon conversion of biomass to CO2 and CO in the fuel reactor have been experimentally studied. A total 60 h run has been obtained with the same batch of oxygen carrier of iron oxide supported with alumina. The results show that CO and H2 concentrations are increased with increasing temperature in the fuel reactor. It is also found that with increasing fuel reactor temperature, both the amount of residual char in the fuel reactor and CO2 concentration of the exit gas from the air reactor are degreased. Carbon conversion rate and gasification efficiency are increased by increasing temperature and H2 production at 870 ℃reaches the highest rate. Scanning electron microscopy (SEM), X-ray diffraction (XRD) and BET-surface area tests have been used to characterize fresh and reacted oxygen carrier particles. The results display that the oxygen carrier activity is not declined and the specific surface area of the oxygen carrier particles is not decreased significantly.

  20. Hydrogen and syngas production from two-step steam reforming of methane using CeO2 as oxygen carrier

    Institute of Scientific and Technical Information of China (English)

    Xing Zhu; Hua Wang; Yonggang Wei; Kongzhai Li; Xianming Cheng


    CeO2 oxygen carrier was prepared by precipitation method and tested by two-step steam reforming of methane (SRM).Two-step SRM for hydrogen and syngas generation is investigated in a fixed-bed reactor.Methane is directly converted to syngas at a H2/CO ratio close to 2∶ 1 at a high temperature (above 750 ℃) by the lattice oxygen of CeO2; methane cracking is found when the reduction degree of CeO2 was above 5.0% at 850 ℃ in methane isothermal reaction.CeO2-δ obtained from methane isothermal reaction can split water to generate CO-free hydrogen and renew its lattice oxygen at 700 ℃; simultaneously, deposited carbon is selectively oxidized to CO2 by steam following the reaction (C+2H2O→CO2+2H2).Slight deactivation in terms of amounts of desired products (syngas and hydrogen) is observed in ten repetitive two-step SRM process due to the carbon deposition on CeO2 surface as well as sintering of CeO2.

  1. CaSO4 and cationic polyelectrolyte as possible pectin precipitants in sugar beet juice clarification

    Directory of Open Access Journals (Sweden)

    Kuljanin Tatjana


    Full Text Available Three pectin preparations were isolated from fresh sugar beet pulp during the 150 minutes of extraction, at pH values of 1, 3.5 and 8.5. CaSO4 precipitant was added to 100 cm3 of 0.1% (wt solution of pectin. Studies were performed with 9 different concentrations of CaSO4 solution (50-450 mg dm-3 with the addition of a cationic polyelectrolyte (cationic PAM in concentrations of 3 and 5 mg dm-3. The efficiency of pectin precipitation was monitored by measuring the zeta potential of pectin preparations. Optimal amounts of precipitant CaSO4, without the use of a cationic polyelectrolyte, were as follows: 490-678 mg CaSO4/g pectin. After the use of a cationic polyelectrolyte, the optimal amounts of CaSO4 were smaller (353-512 mg/g pectin. These quantities are significantly lower than the average amount of CaO used in the conventional clarification process of sugar beet juice (about 9 g/g pectin of sugar beet juice. [Projekat Ministarstva nauke Republike Srbije, br. TR -31055

  2. Analysis Of CaSO4 Precipitation At Seawater Desalination Process

    International Nuclear Information System (INIS)

    Analysis of CaSO4 precipitation has been undertaken. The experiment performed by heating seawater sample from Muara Karang at temperature series from 50, 60, 70, 80, 90 and 95oC for 30 minutes, respectively. CaSO4 precipitate observed through out it each temperatures heating predicted by .calcium ion content, pH and sulfate ion remains in seawater sample solution. According to the experiment result that the calcium sulfate precipitate of seawater desalination through the MSF installation should be exceed supersaturation condition which depend on concentration factor and heating temperatures. The heating temperature below 95oC with concentration factor is 1, 2 and 3 that CaSO4 precipitate unachievable. It means that the MSF desalination installation ,especially at heating range along the inlet pipe into before the brine heater calcium sulfate not occurs

  3. Experiments on biomass gasification using chemical looping with nickel-based oxygen carrier in a 25 kWth reactor

    International Nuclear Information System (INIS)

    Biomass gasification using chemical looping (BGCL) is an innovative biomass gasification technology, which utilizes lattice oxygen from oxygen carrier instead of molecular oxygen from air. This work attempted to investigate the BGCL performance with nickel-based oxygen carrier in a 25 kWth reactor. The new prototype is composed of a high velocity fluidized bed as an air reactor, a cyclone, a bubbling fluidized bed as a fuel reactor, and a loop-seal. At first, the major reactions in the process were presented and chemical reaction thermodynamics in the fuel reactor was analyzed. The NiO/Al2O3 oxygen carrier was then applied in the reactor. Different variables, such as gasification temperature, steam-to-biomass (S/B) ratio and NiO content, were analyzed. The carbon conversion efficiency increased smoothly within the temperature range of 650–850 °C, while the syngas yield reached the maximum of 0.33 Nm3kg−1 at 750 °C. Additionally, based on the tradeoff between carbon conversion efficiency and syngas yield, it was concluded that 30 wt.% was the optimal NiO content. Besides, in order to get high quality syngas with low CO2 emission, CaO-decorated NiO/Al2O3 oxygen carrier was investigated. Experimental results showed that the addition of CaO enhanced the biomass gasification process and increased the syngas yield. - Highlights: • A new 25 kWth prototype was made in this study. • NiO was selected as oxygen carrier in the new prototype. • Gasification temperature, steam-to-biomass ratio and NiO content were investigated. • CaO-decorated NiO/Al2O3 was tested to produce high quality syngas

  4. CaSO4 and cationic polyelectrolyte as possible pectin precipitants in sugar beet juice clarification


    Kuljanin Tatjana; Lončar Biljana; Pezo Lato; Nićetin Milica; Knežević Violeta; Jevtić-Mučibabić Rada


    Three pectin preparations were isolated from fresh sugar beet pulp during the 150 minutes of extraction, at pH values of 1, 3.5 and 8.5. CaSO4 precipitant was added to 100 cm3 of 0.1% (wt) solution of pectin. Studies were performed with 9 different concentrations of CaSO4 solution (50-450 mg dm-3) with the addition of a cationic polyelectrolyte (cationic PAM) in concentrations of 3 and 5 mg dm-3. The efficiency of pectin precipitation was monitored by measu...

  5. Temperature effect during the gamma irradiation of CaSO4: Dy

    International Nuclear Information System (INIS)

    The effect of the irradiation temperature of CaSO4 doped with Dy was investigated in the interval of 77-298 K. The difference in the response at different temperatures increases with the dose. The response for the system at 77 K was about 20% lower in relation to room-temperature readings. The behavior of CaSO4:Dy at low temperatures shows a linear pattern for doses in the range studied. The response is very reproducible and is a good dosimetric system for samples that are irradiated at low temperature.

  6. An alternative method for immediate dose estimation using CaSO4:Dy based TLD badges (United States)

    Singh, A. K.; Menon, S. N.; Dhabekar, Bhushan; Kadam, Sonal; Chougaonkar, M. P.; Babu, D. A. R.


    CaSO4:Dy based Thermoluminescence dosimeters (TLDs) are being used in country wide personnel monitoring program in India. The TL glow curve of CaSO4:Dy consists of a dosimetric peak at 220 °C and a low temperature peak at 120 °C which is unstable at room temperature. The TL integral counts in CaSO4:Dy reduces by 15% in seven days after irradiation due to the thermal fading of 120 °C TL peak. As the dosimetric procedure involves total integrated counts for dose conversion, the dosimeters are typically read about a week after receiving. However in the event of a suspected over exposure, where urgent processing is expected, this poses limitation. Post irradiation annealing treatment is used in such cases of immediate readout of cards. In this paper we report a new and easier to use technique based on optical bleaching for the urgent processing of TLD cards. Optical bleaching with green LED (∼555 nm photons) of 25,000 lux for one and half hour removes the low temperature TL peak without affecting the dosimetric peak. This method can be used for immediate dose estimation using CaSO4:Dy based TLD badges.

  7. Investigation of the performance of a copper based oxygen carrier for chemical looping combustion in a 120 kW pilot plant for gaseous fuels

    International Nuclear Information System (INIS)

    Highlights: • A Cu based oxygen carrier for chemical looping combustion has been tested. • A 120 kW pilot plant designed as dual circulating fluidized bed has been used. • Solids inventory and circulation have been identified as critical for performance. • The results are compared with other pilot plants using the same oxygen carrier. • Recommendations for improved reactor designs have been made based on the results. - Abstract: A copper based oxygen carrier prepared by impregnation on a highly porous alumina support (14.2 wt% active CuO) has been tested in a 120 kW chemical looping pilot plant. This oxygen carrier has already been under investigation in other pilot plants up to 10 kW fuel power and showed very good performance, i.e. full fuel conversion was achieved. During the experiments, natural gas has been used as fuel and variations of several process parameters like temperature, fuel power, solids inventory and solids circulation rate have been performed. The copper particles showed good performance regarding conversion of CO and H2 (almost full conversion) but only moderate conversion of CH4 (up to 80%) was achieved. The three process parameters fuel reactor temperature, solids circulation between air and fuel reactor and solids inventory have been identified as significant parameters for fuel conversion, i.e. increasing one of these parameters improves fuel conversion. Continuous analysis of the oxygen carrier particles revealed an initial decay of active CuO content caused by attrition on the external surface of the particles. The CuO content stabilized after 30 h of operation at around 9 wt% and no further decrease was observed

  8. A review of blood substitutes: examining the history, clinical trial results, and ethics of hemoglobin-based oxygen carriers

    Directory of Open Access Journals (Sweden)

    Jiin-Yu Chen


    Full Text Available The complications associated with acquiring and storing whole blood for transfusions have launched substantial efforts to develop a blood substitute. The history of these efforts involves a complicated mixture of science, ethics, and business. This review focuses on clinical trials of the three hemoglobin-based oxygen carriers (HBOC that have progressed to Phase II or III clinical trials: HemAssist (Baxter; Deerfield, IL, US, PolyHeme (Northfield; Evanston, IL, US, and Hemopure (Biopure; Cambridge, MA, US. Published animal studies and clinical trials carried out in a perioperative setting have demonstrated that these products successfully transport and deliver oxygen, but all may induce hypertension and lead to unexpectedly low cardiac outputs. Overall, these studies suggest that HBOCs resulted in only modest blood saving during and after surgery, no improvement in mortality and an increased incidence of adverse reactions. To date, the results from these perioperative studies have not led to regulatory approval. All three companies instead chose to focus their efforts on large trials of trauma patients in the pre-hospital setting. Baxter abandoned the development of HemAssist after a trial in the U.S. was prematurely halted when the first 100 patients showed significantly increased mortality rates as compared to patients treated with blood products. Northfield's PolyHeme trial demonstrated a non-significant trend towards increased mortality and a very modest reduction in the subsequent need for blood. The testing of Biopure's Hemopure for trauma patients has been halted for several years because of FDA concerns over trial design and study justification. Ethical concerns have also been raised regarding the design and implementation of all HBOC clinical trials. Thus, the available evidence suggests that HemAssist, Polyheme, and Hemopure are associated with a significant level of cardiovascular dysfunction. The next generation of HBOCs remains

  9. Strategies for Small Volume Resuscitation: Hyperosmotic-Hyperoncotic Solutions, Hemoglobin Based Oxygen Carriers and Closed-Loop Resuscitation (United States)

    Kramer, George C.; Wade, Charles E.; Dubick, Michael A.; Atkins, James L.


    Introduction: Logistic constraints on combat casualty care preclude traditional resuscitation strategies which can require volumes and weights 3 fold or greater than hemorrhaged volume. We present a review of quantitative analyses of clinical and animal data on small volume strategies using 1) hypertonic-hyperosmotic solutions (HHS); 2) hemoglobin based oxygen carriers (HBOCs) and 3) closed-loop infusion regimens.Methods and Results: Literature searches and recent queries to industry and academic researchers have allowed us to evaluate the record of 81 human HHS studies (12 trauma trials), 19 human HBOCs studies (3trauma trials) and two clinical studies of closed-loop resuscitation.There are several hundreds animal studies and at least 82 clinical trials and reports evaluating small volume7.2%-7.5% hypertonic saline (HS) most often combined with colloids, e.g., dextran (HSD) or hetastarch(HSS). HSD and HSS data has been published for 1,108 and 392 patients, respectively. Human studies have documented volume sparing and hemodynamic improvements. Meta-analyses suggest improved survival for hypotensive trauma patients treated with HSD with significant reductions in mortality found for patients with blood pressure cardiac output. There is some evidence that HBOCs more efficiently unload oxygen from plasma hemoglobin as well as facilitate RBC unloading. We analyzed one volunteer study, 15 intraoperative trials, and 3 trauma studies using HBOCs. Perioperative studies generally suggest ability to deliver oxygen, but one trauma trial using HBOCs (HemAssist) for treatment of trauma resulted in a dramatic increase in mortality, while an intraoperative trauma study using Polyheme demonstrated reductions in blood use and lower mortality compared to historic controls of patients refusing blood. Transfusion reductions with HBOC use have been modest. Two HBOCs (Hemopure and Polyheme) are now in new or planned large-scale multicenter prehospital trials of trauma treatment. A new

  10. Development of sintered composites CaSO4 doped with Dy and Nd

    International Nuclear Information System (INIS)

    The main of this work was the developing of sintered composites in order to use as thermoluminescent dosimeters using a simple route to preparation, employing high temperature. The composites were prepared with CaSO4.2H2O doped with Dy2O3 and NdO3. Initially CaSO4.2H2O was dehydrated in oven at 100 deg C by 1h. After the addiction dopants and homogenization of compounds, PVA was incorporated to make easy to compaction of composites. The pellets with 6 mm of diameter and 1 mm thickness were sintered at 900 deg C and 1000 deg C by 6 h. The TL emission showed two peaks when the samples were irradiated with beta source (Sr90+Y90). In all cases, the calibration curves presented responses proportional to absorbed dose. The results showed that this material have potential to be used in dosimetry. (author)

  11. Suitability of CaSO4:Tm systems for occupational dosimetry

    International Nuclear Information System (INIS)

    Initial experiments using CaSO4:Tm powder for laboratory measurements of gamma, X and beta measurement exposures are reported. Powder has been embedded in a silastic rubber to study the possibility of using such an arrangement for automated readout of fast neutron exposures. The response of powder is very satisfactory for measuring X and gamma radiation although sensitivity to beta radiation is only 56% of the Radium 226 sensitivity. Light output per unit gamma dose drops by a factor of 100 when CaSO4:Tm powder is embedded in silastic rubber to a 10% loading. Although some enhancement is shown, the response to fast neutrons does not appear to be satisfactory below 1Rem. Extreme sensitivity to light appears to be a problem with this material. Silastic rubber impregnated with phosphor appears to be a suitable material for use in automated systems although further work to improve its sensitivity is required. (author)

  12. Method for compensation the energy dependence of the CaSO4:Dy Tl detector response

    International Nuclear Information System (INIS)

    In this work the results obtained in the compensation of the energy dependence of the response in the case of the CaSO4 doped with Dy detectors are presented. The detectors have been obtained in our laboratory. They are in the shape of tablets with the following dimensions: the diameter is 10 mm and the thickness is 0.8 mm. They are widely used for the monitoring of the environmental areas and personal exposure, mainly in the range of the low values of the absorbed doses. Another advantage of these detectors is their low sensitivity to neutrons and to the influence of the environmental climatic conditions. An acceptable method for reduction of the photon energy dependence of CaSO4:Dy is the use of the suitable metallic filters. A systematic study for a large number of different metallic filters (Pb, Cu, Sn, Stainless Steels, Al) or for different combinations of metallic filters has been carried out. (authors)

  13. Thermoluminescence characteristics of mixture of CaSO4 and SiO2

    International Nuclear Information System (INIS)

    The study on the characteristics of thermoluminescence (TL) spectra for the mixture of CaSO4 and SiO2 was carried out. Four kinds of mixture of CaSO4 and SiO2 with various mass ratios, such as 1:2, 1:1, 4:1, 9:1, were prepared and tested. Four TL peaks are 110, 160, 240, 380 degree C, and they show linearity and stabilization. Especially, the peak of 240 degree C can be used to dating. TL characteristics of gypsum and calcium sulfate were compared. The data can help us in analysis the glow curve for gypsum. It could be useful to luminescence dating for gypsum. (authors)

  14. Modeling the thermoluminescent response of CaSO4:Dy by the MCNPX method

    International Nuclear Information System (INIS)

    This work describes an algorithm for absorbed dose evaluation in the region of X-ray diagnostic energy based on the response of CaSO4:Dy thermoluminescence powder detectors. The absorbed dose was calculated using Monte Carlo simulation code (MCSC) and then compared to the experimental TLD results for X-rays effective energies 60Co gamma radiation. In order to study the photon interaction in the matter, a cylindrical model of 1 cm3 was used. The gamma radiation source was placed at 100 cm to the object; the source is considered as an isotropic source of 60Co. The energy deposited into the cylindrical model was determined by the Monte Carlo N-particle (MCNPX) method. Measurements of the TL phosphors were obtained by irradiating the powder by gamma radiation. TL glow curve of CaSO4:Dy after gamma irradiated at a 1 Gy of absorbed dose was then obtained.

  15. High energy electron beams characterization using CaSO4:Dy+PTFE Phosphors for clinical therapy applications

    International Nuclear Information System (INIS)

    In the present work high energy electron beam dosimetry from linear accelerator (LINACs) for clinical applications using dysprosium doped calcium sulfate embedded in polytetrafluorethylene (CaSO4:Dy+PTFE) was studied. The irradiations were carried out using high electron beams (6 to 18 MeV) from a linear accelerator (LINAC) Varian, CLINAC 2300C/D, for clinical practice purpose. The electron irradiations were obtained using the water solid in order to guarantee electronic equilibrium conditions (EEC). Field shaping for electron beams was obtained with electron cones. Glow curve and other thermoluminescent characteristics of CaSO4:Dy+PTFE were conducted under high electrons beams irradiations. The TL response of the pellets showed an intensity peak centered at around 215 °C. TL response of CaSO4:Dy+PTFE as a function of high electron absorbed dose showed a linearity in a wide range. To obtain reproducibility characteristic, a set of pellets were exposed repeatedly for the same electron absorbed dose. The results obtained in this study can suggest the applicability of CaSO4:Dy+PTFE pellets for high electron beam dosimetry, provided fading is correctly accounted for. - Highlights: ► Developing of CaSO4:Dy to electron beams dosimetry. ► Characterization of caSO4:Dy to radiation safety in LINACs. ► TL characteristics of CaSO4:Dy for electron beams quality control.

  16. Cathodoluminescence and green-thermoluminescence response of CaSO4:Dy,P films

    International Nuclear Information System (INIS)

    We herein report on the cathodoluminescence (CL) and green-thermoluminescence (TL) emission of CaSO4:Dy,P films deposited by the spray pyrolysis method at different temperatures. The samples have been previously structurally and chemically characterized by means of Raman spectroscopy and energy dispersive spectroscopy (EDS). The CL spectra show (i) a broad emission band centered at 374 nm that corresponds to the intrinsic emission of (SO4)2− and (ii) emission bands centered on 486, 574, 668, 758 nm assigned to the electronic transitions of the Dy3+ ions. The TL glow curves of the films showed three groups of components peaked at around of 98, 152 and 300 °C that exhibit a gradual and progressively linear shifting of the Tmax as function of Tstop. This TL behavior is related to a continuum in the trap distribution associated with general or multi-order kinetics and involving continuous processes of trapping–detrapping. The activation energy in the range of 0.97–1.53 eV has been estimated using the initial rise method. - Highlights: ► The CaSO4:Dy,P films were prepared by using the ultrasonic spray pyrolysis method. ► Luminescence spectra of the CaSO4:Dy,P films display the emission bands of the ions (SO4)2− and Dy3+. ► The CaSO4:Dy,P films were irradiated with a 90Sr/90Y beta source. ► The TL intensity of the films depends on the temperature of deposit.

  17. Measurements of Small Exposures of Gamma Radiation with CaSO4:Mn Radiothermoluminescence

    International Nuclear Information System (INIS)

    A system for measurements of small exposures of gamma radiation using CaSO4:Mn thermoluminescence has been developed. The construction and performance of a read-out apparatus is described as well as the construction and characteristics of a simple dosimeter. The reproducibility of the method at various exposures is estimated. 20 μR of 1 MeV gamma radiation can be measured with a reproducibility within ± 50 % (standard deviation)

  18. A study on fabrication and characteristics of CaSO4:Tb TLD

    International Nuclear Information System (INIS)

    In this study, the highly sensitive CaSO4:Tb glass capsule type TLDs are fabricated and their trap parameters are determined. The optimum conditions of fabricating of CaSO4:Tb phosphor was obtained to be in impurity concentration of Tb 1.0 mol percent and sintering of 600 deg C, 2 hr. The glow curve of CaSO4:Tb consists of three glow peaks and these peaks are isolated by thermal bleaching method. Activation energy of the three glow peaks measured by the initial rise, the peak shape and the heating rate method are 0.70, 0.87, and 1.03 eV. The frequency factors are 1.76 X 109, 1.74 X 109, and 9.77 X 108 s-1, and the kinetic orders are 1.12, 1.46, and 1.34, respectively. The isolated glow peals fitted by least square method and optimum temperature range of the main peak for radiation dosimetry is 230 ∼ 295 deg C. (author)

  19. Thermoluminescence properties of home-made CaSO4:Dy For Dosimetry Purposes

    International Nuclear Information System (INIS)

    Dysprosium doped Calcium Sulfate (CaSO4:Dy) had been first prepared by Yamashita in 1968 with method based on acid evaporation in an open system, which pose human health risks, corrosion and pollution to the environment due to sulfuric acid vapor. It has found increasing use in various applications in the field of radiation dosimetry due to their ease of preparation as compared to many other sensitive TL materials. Many researchers emphasized that the grain size and impurities influence the relative intensities of the broad glow peaks as well as overall sensitivities. In this paper, we introduce a new method of preparation for avoiding all of these disadvantages and improving the main TL materials properties, which required for dosimetric use. The main TL characteristics of home-made CaSO4:Dy .crystals with different concentrations are investigated alter the preparation and heat treatment conditions. The results indicated a linear response from 5μ .Gy up to 10 Gy with the highest sensitivity obtained at 0.25 mol % and optimum sensitivity at less than 75 jam grain sizes. Three peaks at 137 degree C, 222 degree C and 311 degree C were obtained. We conclude to use our home-made prepared CaSO4:Dy with 0.25 mol % concentration for gamma-ray dosimetry as more sensitive and cheaper than commercial phosphor (TLD-900). This will increase the routine and research work in the area of TL dosimetry

  20. Study on the response of indigenously developed CaSO4:Dy phosphor based neutron dosemeter

    International Nuclear Information System (INIS)

    In the present paper we report indigenous development of a neutron sensitive thermoluminescent (TL) dosemeter based on CaSO4:Dy Teflon TL disc. For large scale neutron monitoring of about 15,000 workers, engaged in the nuclear fuel cycle operation, the new dosemeter can be easily incorporated in the present TLD badge system used in personnel monitoring in our country just by a small change in the designing of the badge cassette. The study includes indigenous development of neutron dosemeter, response of the neutron dosemeter in terms of operational quantity to different energies of neutrons under various irradiation conditions. It was found that the thermal neutron sensitivity of the CaSO4:Dy Teflon neutron disc is about one third of TLD-600. However the thermal neutron sensitivity with respect to CaSO4:Dy Teflon gamma disc is about 42 times for in air irradiation and about 84 times for on-phantom irradiation conditions. This newly developed neutron disc can be used as a routine TL dosemeter in the mixed fields of gamma and neutron for neutron energy upto 500 keV for radiation workers engaged in nuclear fuel cycle operation. (author)

  1. Cathodoluminescence and Raman characteristics of CaSO4:Tm3+, Cu phosphor

    International Nuclear Information System (INIS)

    The physical characterization and phosphor emission spectra are presented for CaSO4 doped with Tm and Cu. All spectral wavelengths are related to electronic transitions of Tm3+ ions. The powder X-ray diffraction pattern showed that the compound exhibits orthorhombic structure and all reflections were indexed without any other secondary impurity phases. Chemical and structural properties of the samples have been characterized by means of Raman spectroscopy and environmental scanning electron microscope (ESEM) with an attached X-ray energy dispersive system (EDS). Group frequencies concept is essential point to the interpretation of the bands due to the main SO4 vibrational units and these displayed main characteristic intensive Raman bands including typical strong intensity at 1016 cm−1 that corresponds to ν1SO4 vibrational mode. From the spatially-resolved cathodoluminescence (CL) spectrum, main emission bands of Tm3+ centered at 346, 362, and 452 nm, due to the respective transitions of 3P0→3H4, 1D2→3H6, 1D2→3F4 were clearly identified. The study is novel as no such CL-ESEM data are available for this doped compound. - Highlights: • Characteristic and cathodoluminescence properties of CaSO4:Tm3+, Cu have been investigated. • Several sharp and strong CL emission bands due to rare earth ion were observed for rare earth doped sample. • The nature and limitation of the interaction between CaSO4 and the activator ions were discussed

  2. Influence of the formation- and passivation rate of boron-oxygen defects for mitigating carrier-induced degradation in silicon within a hydrogen-based model

    International Nuclear Information System (INIS)

    A three-state model is used to explore the influence of defect formation- and passivation rates of carrier-induced degradation related to boron-oxygen complexes in boron-doped p-type silicon solar cells within a hydrogen-based model. The model highlights that the inability to effectively mitigate carrier-induced degradation at elevated temperatures in previous studies is due to the limited availability of defects for hydrogen passivation, rather than being limited by the defect passivation rate. An acceleration of the defect formation rate is also observed to increase both the effectiveness and speed of carrier-induced degradation mitigation, whereas increases in the passivation rate do not lead to a substantial acceleration of the hydrogen passivation process. For high-throughput mitigation of such carrier-induced degradation on finished solar cell devices, two key factors were found to be required, high-injection conditions (such as by using high intensity illumination) to enable an acceleration of defect formation whilst simultaneously enabling a rapid passivation of the formed defects, and a high temperature to accelerate both defect formation and defect passivation whilst still ensuring an effective mitigation of carrier-induced degradation

  3. Influence of the formation- and passivation rate of boron-oxygen defects for mitigating carrier-induced degradation in silicon within a hydrogen-based model

    Energy Technology Data Exchange (ETDEWEB)

    Hallam, Brett, E-mail:; Abbott, Malcolm; Nampalli, Nitin; Hamer, Phill; Wenham, Stuart [School of Photovoltaics and Renewable Energy Engineering, Level 1 Tyree Energy Technologies Building, University of New South Wales, Kensington, NSW 2052 (Australia)


    A three-state model is used to explore the influence of defect formation- and passivation rates of carrier-induced degradation related to boron-oxygen complexes in boron-doped p-type silicon solar cells within a hydrogen-based model. The model highlights that the inability to effectively mitigate carrier-induced degradation at elevated temperatures in previous studies is due to the limited availability of defects for hydrogen passivation, rather than being limited by the defect passivation rate. An acceleration of the defect formation rate is also observed to increase both the effectiveness and speed of carrier-induced degradation mitigation, whereas increases in the passivation rate do not lead to a substantial acceleration of the hydrogen passivation process. For high-throughput mitigation of such carrier-induced degradation on finished solar cell devices, two key factors were found to be required, high-injection conditions (such as by using high intensity illumination) to enable an acceleration of defect formation whilst simultaneously enabling a rapid passivation of the formed defects, and a high temperature to accelerate both defect formation and defect passivation whilst still ensuring an effective mitigation of carrier-induced degradation.

  4. Effects of excess oxygen introduced during sputter deposition on carrier mobility in as-deposited and postannealed indium-tin-oxide films

    International Nuclear Information System (INIS)

    Electrical and structural properties of indium-tin-oxide (ITO) films with various Sn concentrations deposited under a high oxygen partial pressure were examined to find out how the excess oxygen behaves as a scattering and trapping center of electron carriers and to show evidence that excess oxygen is weakly bound with Sn4+ ions on In3+ sites with single-charge SnIn . ITO films with Sn concentrations of 1-25 wt % were deposited on glass substrates by rf sputtering under various oxygen concentrations in the discharge gas (0.3%-100%); the substrate temperature was kept at 773 K during deposition. With increasing O2 flow ratio in the discharge gas from 0.3% to 100%, the Hall mobility and the carrier density were found to decrease from ∼40 to ∼20 cm2 V-1 s-1 and from ∼5.0x1020 to ∼2.0x1018 cm-3, respectively. The dependence of the slope of mobility-temperature curve on the O2 flow ratio and Sn concentration has been examined. For high Sn concentration, the slope changes from negative to positive as the O2 flow rate increases. The slope of the curve for a film with Sn concentration of 8 wt % deposited at an O2 flow ratio of 100% changes from positive to negative after postannealing at 473 K for 30 min. in N2. These results suggest that the oxygen attaches weakly to Sn4+ and that the oxygen plays a role in the scattering and trapping center. It is also found that oxygen ions mainly exist not in interstitial quasianion sites but in the grain boundaries because of the constant lattice parameter after annealing

  5. Measurement of absorbed dose for high energy electron using CaSO4: Tm-PTFE TLD

    International Nuclear Information System (INIS)

    In this study, the highly sensitive CaSO4: Tm-PTFE TLDs has been fabricated for the purpose of measurement of high energy electron. CaSO4: Tm phosphor powder was mixed with polytetrafluoroethylene(PTFE) powder and moulded in a disk type(diameter 8.5mm, thickness 90mg/cm2) by cold pressing. The absorbed dose distribution and ranges for high energy electron were measured by using the CaSO4: Tm-PTFE TLDs. The ranges determined were R100=3D14.5mm, R50=3D24.1mm and Rp=3D31.8mm, respectively and the beam flatness, the variation of relative dose in 80% of the field size, was 4.5%. The fabricated CaSO4: Tm-PTFE TLDs may be utilized in radiation dosimetry for personal, absorbed dose and environmental monitoring.=20

  6. CaMn0.875Ti0.125O3 as oxygen carrier for chemical-looping combustion with oxygen uncoupling (CLOU)—Experiments in a continuously operating fluidized-bed reactor system

    KAUST Repository

    Rydén, Magnus


    Particles of the perovskite material CaMn0.875Ti0.125O3 has been examined as oxygen carrier for chemical-looping with oxygen uncoupling, and for chemical-looping combustion of natural gas, by 70h of experiments in a circulating fluidized-bed reactor system. For the oxygen uncoupling experiments, it was found that the particles released O2 in gas phase at temperatures above 720°C when the fuel reactor was fluidized with CO2. The effect increased with increased temperature, and with the O2 partial pressure in the air reactor. At 950°C, the O2 concentration in the outlet from the fuel reactor was in the order of 4.0vol%, if the particles were oxidized in air. For the chemical-looping combustion experiments the combustion efficiency with standard process parameters was in the order of 95% at 950°C, using 1000kg oxygen carrier per MW natural gas, of which about 30% was located in the fuel reactor. Reducing the fuel flow so that 1900kg oxygen carrier per MW natural gas was used improved the combustion efficiency to roughly 99.8%. The particles retained their physical properties, reactivity with CH4 and ability to release gas-phase O2 reasonably well throughout the testing period and there were no problems with the fluidization or formation of solid carbon in the reactor. X-ray diffraction showed that the particles underwent changes in their phase composition though. © 2010 Elsevier Ltd.

  7. Validation of the stamping method for CaSO4:RE + Teflon® pellets production

    International Nuclear Information System (INIS)

    The IPEN method for the CaSO4:RE + Teflon® production, developed and patented at the Dosimetric Materials Laboratory - LMD/IPEN in the earlier 1980's, is highly time-demanding, so that the use of the stamping method, already widely industrially applied, would enhance the CaSO4:RE + Teflon® pellets production. Thus, validating the stamping method, by comparing the dosimetric properties of a batch of pellets produced by each method, became a must. The stamped batch presents the same mean non-irradiated signals either after sintering or annealing while IPEN batch mean non-irradiated signals vary in 23%. The mean TL signal after irradiation was about 50 nC, but the standard deviation varies from 20% to 33% for IPEN batch and keeps in 10% for the stamped batch. 24 h after the irradiation, the TL signal decreased to about 35 nC, with no differences in IPEN batch standard deviation and a decrease to 5% in stamped batch standard deviation, for the five performed essays. Calibration curves present a linear behavior over the entire studied dose range and the same coefficients for both methods, however, the uncertainties in the coefficients determined to the calibration curve obtained with stamped pellets are significantly smaller, leading to a more precise dose determination. This results show that the stamping method produces more homogeneous batches, with pellets that maintain the dosimetric characteristics of the detectors produced by IPEN method, in such a way that the stamping method can substitute with advantages the IPEN method in the CaSO4:RE + Teflon® dosimetric pellets production. (author)

  8. Development of CaSO4:Dy TL dosimetry badge system for mixed radiation fields

    International Nuclear Information System (INIS)

    A personnel dosimetry badge system is designed using CaSO4:Dy TL material for discriminating energy components in mixed radiation fields. The new badge system consists of four dosimetry filtered area. Each of these areas utilizes a unique set of filters to provide specific dosimetric information. This TLD badge system is designed by using MCNP code. The prototype TLD badge is also tested by experimental irradiation on PMMA slab phantom. The results of experimental test satisfy the criteria for testing personnel dosimetry systems specified in the ANSIN13.11(1983). (2 figs., 3 tabs.)

  9. Thermoluminescent response of CaSO4: Dy + PTFE to beta particles

    International Nuclear Information System (INIS)

    In this work the results of studying the thermoluminescent properties of CaSO4: Dy + PTFE are presented when it is irradiated with beta particles. The conclusion was the obtention of the Tl response curve in function of dose is that to desexcite the dosemeters at temperature 300 C during 30 minutes and after that were irradiated at different times in groups and to do the reading of dosemeter, it can be observed that a greater irradiation time major is the Tl response and this depends of the material has been used. (Author)

  10. Microscale electrochemical cell using plaster (CaSO4) as liquid junction


    Yuthapong Udnan


    A microscale apparatus for electrochemical cell in which plaster (CaSO4) was used as liquid junction has been developed. A glass tube (0.5 cm ID x 5.0 cm) was used to prepare each half-cell. The potentials of the resulting galvanic cells were measured by a multimetre and were compared to those of the galvanic cells in which agar was used as liquid junction. It was found that the potentials produced by the galvanic cells with plaster as liquid junction are not significantly different from tho...

  11. Characteristics Of Dosimeter TL CaSO4:Dy Glass Capillaries For Environmental Radiation Dose Monitoring

    International Nuclear Information System (INIS)

    research on the characteristic of dosimeter TL CaSO4 : Dy glass capillaries for environmental dose radiation have been carried out. The results obtained are uniform response and reproducibility during three cycles consumption with average percentage standard deviation of 7.31 % and 5.45%. The response dose is linear and has a minimum detectable dose of 0.01 mGy, sunshine effect with non-penetrating light capsule of 4.65%, humidity effects is not significant by using non-penetrating light capsule. Radiation dose information during 30 days are fading 25%

  12. Improvement in the dosimetric CaSO4: Dy obtention method

    International Nuclear Information System (INIS)

    With the purpose of saving up in the dosimetric CaSO4: Dy production, a new method was developed to obtain single crystals. In this method the nitrogen flux used to carry the acid vapour was substituted by compressed air. It was compared all dosimetric properties of the crystals. There is no alteration in the glow curve. The sensitivity is the same in both cases and the lower detection limit is 3.8 x 10-8C.Kg-1 (150 μR)

  13. Effects of heliox as carrier gas on ventilation and oxygenation in an animal model of piston-type HFOV: a crossover experimental study

    Directory of Open Access Journals (Sweden)

    Hiroma Takehiko


    Full Text Available Abstract Objective This study aimed to compare gas exchange with heliox and oxygen-enriched air during piston-type high-frequency oscillatory ventilation (HFOV. We hypothesized that helium gas would improve both carbon dioxide elimination and arterial oxygenation during piston-type HFOV. Method Five rabbits were prepared and ventilated by piston-type HFOV with carrier 50% helium/oxygen (heliox50 or 50% oxygen/nitrogen (nitrogen50 gas mixture in a crossover study. Changing the gas mixture from nitrogen50 to heliox50 and back was performed five times per animal with constant ventilation parameters. Arterial blood gas, vital function and respiratory test indices were recorded. Results Compared with nitrogen50, heliox50 did not change PaCO2 when stroke volume remained constant, but significantly reduced PaCO2 after alignment of amplitude pressure. No significant changes in PaO2 were seen despite significant decreases in mean airway pressure with heliox50 compared with nitrogen50. Conclusion This study demonstrated that heliox enhances CO2 elimination and maintains oxygenation at the same amplitude but with lower airway pressure compared to air/O2 mix gas during piston-type HFOV.

  14. Measurement of gamma attenuation for ANR end shield model using CaSO4:Dy phosphor

    International Nuclear Information System (INIS)

    Highlights: ► Designing of Advanced Nuclear Reactor (ANR) end shield model. ► Measurement of gamma attenuation factor using CaSO4:Dy TL phosphor. ► Measurement of gamma attenuation factor under different conditions. ► Use of gamma attenuation factor for the actual end shield of ANR. ► Radiation level in the accessible area of ANR well below the permissible limit. - Abstract: In the present study, gamma attenuation factors were measured for End shield model of Advanced Nuclear Reactor (ANR). The model is of the size 700 × 700 × 1250 mm3 and made of steel ball and water mixture with 2 × 2 lattice locations at the centre of the model. The measurements were carried out using CaSO4:Dy TL phosphor. The streaming of gamma rays (includes core gamma, fission product gamma, activation gamma and capture gamma) was found to be attenuated by a factor of about 1500–4000 at a distance of 1125 mm from the incident face of the model, when it is filled with the mixture of water and steel ball. The corresponding exposure rate of streaming gamma rays was found to be about 1.2–2 R/h. The attenuation factors derived from the study was used for the designing of actual End shield for ANR

  15. CaSO4:Dy and/or Tm: study of its properties for dosimetry application

    International Nuclear Information System (INIS)

    In order obtain in practical and cheap solid state dosimeter with high sensitivity, a technique initially developed to cold press a mixture of suitable materials in their powder form sensitive to radiation. The material initially used was natural CaF2 (fluorite) for this salt was extensively studied in radiation dosimetry since it shows a thermoluminescent (TL) effect after radiation. However, natural calcium fluorite shows two main disadvantages: its high senstivity to room light and the impossibility to control its impurity content due to its natural origin. Calcium sulphate was thus used as a good substitute of fluorite. Rare earths doped calcium sulphate shows a high TL sensitivity and is not disturbed by light. It is also easily obtained in the laboratory under controlled conditions so to get reproducible impurity content. The best dosimeters that can be produced with rare earth doped calcium sulphate are CaSO4:Dy and CaSO4:Tm. Calcium sulphate, simultaneously doped with Tm and Dy was produced and 100% increase was obtained in the TL sensitivity when compared with the individually are earth doped calcium sulphate. (Author)

  16. NiO/Al2O3 oxygen carriers for chemical-looping combustion prepared by impregnation and deposition-precipitation methods


    Gayán Sanz, Pilar; Dueso, Cristina; Abad Secades, Alberto; Adánez Elorza, Juan; Diego Poza, Luis F. de; García Labiano, Francisco


    Ni-based oxygen carriers (OC) with different NiO content were prepared by incipient wet impregnation, at ambient (AI), and hot conditions (HI) and by deposition-precipitation (DP) methods using -Al2O3 and -Al2O3 as supports. The OC were characterized by BET, Hg porosimetry, mechanical strength, TPR, XRD and SEM/EDX techniques. Reactivity of the OC was measured in a termogravimetric analyzer and methane combustion selectivity towards CO2 and H2O, attrition rate, and agglomerat...

  17. A quantitative discussion on band-gap energy and carrier density of CdO in terms of temperature and oxygen partial pressure

    International Nuclear Information System (INIS)

    Calculations relative to the band-gap energy shift and carrier spatial density in cadmium oxide are performed in terms of the oxygen partial pressure and substrate temperature relative to the deposition process in the crystal growth of the above material, starting from the consideration of the Fermi energy of an exciton gas. In particular, the band-gap shift experienced by cadmium oxide in terms of the corresponding partial pressure of oxygen is considered as well as the electron spatial density as a function of the pressure in question. Influence of temperature is discussed by estimating the average rate of variation of the band-gap shift versus temperature. In addition, the sensitivity of the above-mentioned shift to temperature is studied by means of a suitable parameter

  18. Autoradiographic determination of regional cerebral blood flow and metabolism in conscious rats after fluid resuscitation from haemorrhage with a haemoglobin-based oxygen carrier. (United States)

    Waschke, K F; Albrecht, D M; van Ackern, K; Kuschinsky, W


    The effects of resuscitation fluids on the brain have been investigated in previous studies by global measurements of cerebral blood flow and metabolism. In this study we have examined the effects of a novel haemoglobin-based oxygen carrier on local cerebral blood flow (LCBF) and local cerebral glucose utilization (LCGU) after resuscitation from a volume-controlled haemorrhage of 30 min (3.0 ml/100 g body weight) with ultrapurified, polymerized, bovine haemoglobin (UPBHB). LCBF and LCGU were measured in 34 brain structures of conscious rats 2 h after resuscitation using quantitative iodo(14C)antipyrine and 2-(14C)-deoxy-D-glucose methods. The data were compared with a control group without haemorrhage and fluid resuscitation. In the haemorrhage group, LCBF increased after resuscitation by 12-56% in the different brain structures (mean 36%). LCGU changed less (0 to +18%, mean +9%). In the control group there was a close relationship between LCGU and LCBF (r = 0.95). After fluid resuscitation the relationship was preserved (r = 0.95), although it was reset at a higher ratio of LCBF to LCGU (P < 0.05). We conclude that fluid resuscitation of a 30 min volume-controlled haemorrhage using the haemoglobin-based oxygen carrier, UPBHB, induced a moderate degree of heterogeneity in the resulting changes of LCGU and LCBF. Local disturbances of cerebral blood flow or metabolism were not observed. PMID:7999496

  19. Dosimetric characteristics and radiation monitoring with CaSO4(Dy):NaCl pellets

    International Nuclear Information System (INIS)

    CaSO4(Dy):NaCl Tl dosimeters, in the form of pellets, are used in the field for a period of one month. Before using these pellets for environmental and personnel radiation monitoring some of the important dosimetric characteristics like fading reusability and effect of ambient light are investigated and described. The pellets are used with plastic and lead filters for personnel and environmental radiation monitoring and the results obtained with the lead filters are in good agreement with those of the energy independent LiF dosimeters. A new combination of plastic, aluminium and lead filters is suggested for dose measurements in a mixed field of X, gamma and beta radiations. (Author)

  20. Optimization of the obtaining method of CaSO4: Dy + Ptfe dosimeters

    International Nuclear Information System (INIS)

    This work contain the obtained results of studying the response when irradiating to different dose of X-rays, dosimeters of CaSO4: Dy + Ptfe using different lapses of time in their preparation (a lot of selected dosimeters of an elaboration process of 3 days and another of an elaboration process of 2 hours). For the elaboration of the powdered material, the evaporation method was used; the irradiation were carried out in a lineal accelerator Elekta Synergy property of the National Medical Center, 20 de November. The similarities and differences are shown among the two dosimeters lots together with an analysis of the shine curves and of calibration selecting those that presented a better behaviour and a more rea liable response. (Author)

  1. Preparation and structural characterization of the thermoluminescent material CaSO4: Dy

    International Nuclear Information System (INIS)

    The grade of crystallinity of a material is important so that the one is presented the thermoluminescence phenomenon; for what is necessary to study those structural characteristic of a TL material and to correlate them with its TL response when being irradiated with ionizing radiation. The calcium sulfate activated with Dysprosium (CaSO4: Dy) it is a material that has demonstrated its efficiency in the dosimetry of the ionizing radiation for the thermoluminescence method. In this work the structural characterization of this prepared material for the recrystallization method by means of the evaporation of the solvent and their relationship with their TL response is presented. The results showed that the best material to be used in thermoluminescent dosimetry presents a crystalline structure in orthorhombic phase and a particle size in the interval of 80 μm to 200 μm. (Author)

  2. Effect of the temperature in the sensitivity of CaSO4: Dy

    International Nuclear Information System (INIS)

    Sensitivity of a Tl material is one of the most important properties for dosimetry. This property is optimized by means of various processes such as the incorporation of different dopants into the matrix material, the application of certain doses of ionizing radiation and carefully controlled thermal treatments among others. Results obtained of studying the sensitivity of diverse preparations of CaSO4: Dy submitted different thermal treatments are presented. The material, which presented the highest sensitivity, was that one it was heated to 800 C during one hour. When the temperature was raised over this value it was observed that sensitivity drops again. In other hand, as the heating rate in lowing down, during the readout, the height of the glow curve decreases proportionally. The temperature of the maximum of the main peak also decreases. (Author)

  3. Isothermal gas chromatography of short-lived Hf isotopes and element 104 in chlorinating, oxygen containing carrier gas

    Energy Technology Data Exchange (ETDEWEB)

    Jost, D.T.; Dressler, R.; Eichler, B.; Piguet, D.; Tuerler, A.; Gaeggeler, H.W.; Gaertner, M. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Grantz, M.; Huebener, S. [FZR (Germany); Buklanov, G.; Lebedev, V.; Timkhin, S.; Vedeneev, M.V.; Yakushev, A.; Zvara, I. [Joint Inst. for Nuclear Research, Dubna (Russian Federation)


    Based on thermodynamic state functions retention times of Hf and element 104 were calculated in the case of the simple adsorption of the tetrachlorides and the case of a complex adsorption involving a substitution process with oxygen in the chlorinating gas. Preliminary results for {sup 261}104 and Hf are shown. (author) 1 fig., 1 tab., 3 refs.

  4. CeO2 as the Oxygen Carrier for Partial Oxidation of Methane to Synthesis Gas in Molten Salts: Thermodynamic Analysis and Experimental Investigation

    Institute of Scientific and Technical Information of China (English)


    A new technique - the direct partial oxidation of methane to synthesis gas using lattice oxygen in molten salts medium has been introduced. Using CeO2 as the oxygen carrier, thermodynamic data were calculated in the reaction process, and the results indicated that direct partial oxidation of methane to synthesis gas using lattice oxygen of cerium oxide is feasible in theory. In a stainless steel reactor, the effects of temperature and varying amounts of γ-Al2O3 supported CeO2 on CH4 conversion,H2 and CO selectivity, were investigated, respectively. The results show that 10% CeO2/γ-Al2O3 has the maximal reaction activity at a temperature of 865 ℃ and above, the H2/CO ratio in the gas that has been produced reaches 2 and the CH4 conversion, H2 and CO selectivity reached the following percentages: i.e.61%, 89%, and 91% at 870 ℃, respectively. In addition, increase of reaction temperature is favorable for the partial oxidation of methane.

  5. Phase relation of CaSO4 at high pressure and temperature up to 90 GPa and 2300 K (United States)

    Fujii, Taku; Ohfuji, Hiroaki; Inoue, Toru


    Calcium sulfate (CaSO4), one of the major sulfate minerals in the Earth's crust, is expected to play a major role in sulfur recycling into the deep mantle. Here, we investigated the crystal structure and phase relation of CaSO4 up to ~90 GPa and 2300 K through a series of high-pressure experiments combined with in situ X-ray diffraction. CaSO4 forms three thermodynamically stable polymorphs: anhydrite (stable below 3 GPa), monazite-type phase (stable between 3 and ~13 GPa) and barite-type phase (stable up to at least 93 GPa). Anhydrite to monazite-type phase transition is induced by pressure even at room temperature, while monazite- to barite-type transition requires heating at least to 1500 K at ~20 GPa. The barite-type phase cannot always be quenched from high temperature and is distorted to metastable AgMnO4-type structure or another modified barite structure depending on pressure. We obtained the pressure-volume data and density of anhydrite, monazite- and barite-type phases and found that their densities are lower than those calculated from the PREM model in the studied P-T conditions. This suggests that CaSO4 is gravitationally unstable in the mantle and fluid/melt phase into which sulfur dissolves and/or sulfate-sulfide speciation may play a major role in the sulfur recycling into the deep Earth.

  6. Confinement effects for ionic carriers in SrTiO3 ultrathin films: first-principles calculations of oxygen vacancies. (United States)

    Kotomin, E A; Alexandrov, V; Gryaznov, D; Evarestov, R A; Maier, J


    One-dimensional confinement effects are modelled within the hybrid HF-DFT LCAO approach considering neutral and single-charged oxygen vacancies in SrTiO(3) ultrathin films. The calculations reveal that confinement effects are surprisingly short-range in this partly covalent perovskite; already for film thickness of 2-3 nm (and we believe, similar size nanoparticles) only the surface-plane defect properties differ from those in the bulk. This includes a pronounced decrease of the defect formation energy (by ∼1 eV), a much deeper defect band level and a noticeable change in the electronic density redistribution at the near-surface vacancy site with respect to that in the bulk. The results also show that the size effect pertains to the interactions between the oxygen vacancy and two neighboring titanium atoms and orientation (parallel or perpendicular to the surface) of the Ti-V(O)-Ti complex. In particular, we predict considerable oxygen vacancy segregation towards the surface. PMID:21116562

  7. Thermoluminescent characteristics of LiF:Mg, Cu, P and CaSO4:Dy for low dose measurement. (United States)

    Del Sol Fernández, S; García-Salcedo, R; Mendoza, J Guzmán; Sánchez-Guzmán, D; Rodríguez, G Ramírez; Gaona, E; Montalvo, T Rivera


    Thermoluminescence (TL) characteristics for LiF:Mg, Cu, P, and CaSO4:Dy under the homogeneous field of X-ray beams of diagnostic irradiation and its verification using thermoluminescence dosimetry are presented. The irradiation were performed utilizing a conventional X-ray equipment installed at the Hospital Juárez Norte of México. Different thermoluminescence characteristics of two material were studied, such as batch homogeneity, glow curve, linearity, detection threshold, reproducibility, relative sensitivity and fading. Materials were calibrated in terms of absorbed dose to the standard calibration distance and they were positioned in a generic phantom. The dose analysis, verification and comparison with the measurements obtained by the TLD-100 were performed. Results indicate that the dosimetric peak appears at 202°C and 277.5°C for LiF:Mg, Cu, P and CaSO4:Dy, respectively. TL response as a function of X-ray dose showed a linearity behavior in the very low dose range for all materials. However, the TLD-100 is not accurate for measurements below 4mGy. CaSO4:Dy is 80% more sensitive than TLD-100 and it show the lowest detection threshold, whereas LiF:Mg, Cu, P is 60% more sensitive than TLD-100. All materials showed very good repeatability. Fading for a period of one month at room temperature showed low fading LiF:Mg, Cu, P, medium and high for TLD-100 and CaSO4:Dy. The results suggest that CaSO4:Dy and LiF:Mg, Cu, P are suitable for measurements at low doses used in radiodiagnostic. PMID:26922395

  8. CaMn0.9Mg0.1O3-δ as Oxygen Carrier in a Gas-Fired 10 kWth Chemical-Looping Combustion Unit


    Källen, Malin; Rydén, Magnus; Dueso, Cristina; Mattisson, Tobias; Lyngfelt, Anders


    Spray dried particles of the perovskite material CaMn0.9Mg0.1O3-δ have been examined as oxygen carrier for chemical-looping combustion of natural gas. The experiments have been conducted in a continuously operating reactor with the nominal size 10 kWth. The oxygen carrier particles showed excellent ability to convert fuel and complete combustion was reached at certain conditions. In general, the CO2 yield increased with increased fuel reactor temperature and with increased circulation rate. T...

  9. Microscale electrochemical cell using plaster (CaSO4 as liquid junction

    Directory of Open Access Journals (Sweden)

    Yuthapong Udnan


    Full Text Available A microscale apparatus for electrochemical cell in which plaster (CaSO4 was used as liquid junction has been developed. A glass tube (0.5 cm ID x 5.0 cm was used to prepare each half-cell. The potentials of the resulting galvanic cells were measured by a multimetre and were compared to those of the galvanic cells in which agar was used as liquid junction. It was found that the potentials produced by the galvanic cells with plaster as liquid junction are not significantly different from those of the cells with agar as liquid junction and close to the theoretical values. In addition, when the developed apparatus was used for the study of electrolysis of potassium iodide solution, it was found that the electrolytic cell made from the microscale apparatus with plaster liquid junction can distinctly separate the reactions occurring at the anode and the cathode. Moreover, the lifetime of the plaster liquid junction is much greater than that of the agar liquid junction.

  10. Thermal history and reusability of CaSO4 : Dy teflon TLD discs

    International Nuclear Information System (INIS)

    The effect of thermal history on the thermoluminescent (TL) sensitivity of CaSO4 : Dy teflon thermoluminescent dosimetry (TLD) discs has been studied in the temperature range of 250 - 4000 C from the point of view of their reusability in repeated measurements. 100 discs each of 13.5 mm diam. and 0.8 mm thickness were mechanically fixed on to the aluminium cards (three on each) used for the TLD personnel monitoring badge. The cards were subjected to readout-anneal cycle, annealing being done at 2500C for 1 hr duration and removing 1 card after each cycle. The procedure was continued till all the cards were removed. At the end all the cards were given a 2 R gamma radiation exposure from 60Co source and after two days were read. TL sensitivity of the cards was found to decrease and optical density increase with the number of cycles. Teflon discs are found to get coloured during the readout in a TLD reader or during the readout-anneal process when the maximum temperature reached by the heater strip is below 3500C, where as they do not get coloured if annealed isothermally at 4000C. The colouring is found to be independent of the heating and cooling rate. (M.G.B.)

  11. The Study Of Briquettes Produced With Bitumen, Caso4 And Starch As Binders.

    Directory of Open Access Journals (Sweden)

    ,Ikelle Issie Ikelle


    Full Text Available The work was based on production and study of the properties of smokeless briquettes of various compositions with coal and rice husk. Different briquettes were produced with starch, bitumen and CaSO4 as the binders while Ca(OH2 was the desulphurizing agent. The proximate analysis of the raw coal sample showed ash content 19.12%, moisture content 6.25%, volatile matter 41.12%, fixed carbon 33.51% and calorific value 117 KJ/g, the rice husk had the following values ash content 7.53%, moisture content 10.48%, volatile matter 68.74%, fixed carbon 13.25% and calorific value 65.24 KJ/g. The briquettes produced are in the following ratio of mixtures of coal and rice husk 100:0, 80:20, 60:40, 40:60, 20:80 and 0:100 respectively. The prepared briquettes were sun dried for seven days, subjected to various tests to assess their fuel quality. The briquettes produced with starch as the binder had better results for faster ignition time, lower amounts of sulphur emissions during burning, highest calorific values and longer burning time for all the different compositions.

  12. Study of gaussian fitting methods applied to thermoluminescent emission spectrum of CaSO4:Dy

    International Nuclear Information System (INIS)

    In the present work, two methods used to represent the peaks of the thermoluminescence (TL) glow curve of CaSO4:Dy, from a gaussian approximation, are evaluated. Several glow curves with single and double peaks and known parameters were computationally simulated. Two procedures were applied to the data: gaussian curve fitting to the simulated data by the least squares method; and peak approximation by a gaussian function, from a method developed in the Applied Physics Division of IEAv/CTA. The obtained results (gaussian curve areas) in comparison with the original area of the TL glow curve generated for the single peak case show a tendency of underestimate the real area from 0.8 to 7.0%, depending on the fitting method applied. For the double peak case, it was observed an emphasized tendency of overestimate the original curve area from 3.7 to 6.2%, depending on the fitting method used. The obtained result is discussed in relation to the utilization of the method as a dosimetry routine, its implications and limitations. (author)

  13. Modelling of a hybrid culture system with a stationary layer of liquid perfluorochemical applied as oxygen carrier

    Directory of Open Access Journals (Sweden)

    Pilarek Maciej


    Full Text Available A mathematical model of a hybrid culture system supported with a stationary layer of liquid perfluorochemical (PFC as a source of O2 for cells which grow in the aqueous phase of culture medium has been developed and discussed. The two-substrate Monod kinetics without inhibition effects, i.e. the Tsao-Hanson equation, has been assumed to characterise the biomass growth. The Damköhler number which relates the growth rate to the mass transfer effects has been used to appraise the regime (i.e. diffusion-limited or kinetics of the whole process. The proposed model predicted accurately previously published data on the submerged batch cultures of Nicotiana tabacum BY-2 heterotrophic cells performed in a culture system supported with a stationary layer of hydrophobic perfluorodecalin as a liquid O2 carrier. Estimated values of the parameters of the model showed that the process proceeded in the kinetics regime and the growth kinetics, not the effects of the mass transfer between aqueous phase and liquid PFC, had essential influence on the growth of biomass.

  14. Effect of dissolved oxygen on nitrate removal using polycaprolactone as an organic carbon source and biofilm carrier in fixed-film denitrifying reactors. (United States)

    Luo, Guozhi; Xu, Guimei; Gao, Jinfang; Tan, Hongxin


    Nitrate-nitrogen (NO3(-)-N) always accumulates in commercial recirculating aquaculture systems (RASs) with aerobic nitrification units. The ability to reduce NO3(-)-N consistently and confidently could help RASs to become more sustainable. The rich dissolved oxygen (DO) content and sensitive organisms stocked in RASs increase the difficulty of denitrifying technology. A denitrifying process using biologically degradable polymers as an organic carbon source and biofilm carrier was proposed because of its space-efficient nature and strong ability to remove NO3(-)-N from RASs. The effect of dissolved oxygen (DO) levels on heterotrophic denitrification in fixed-film reactors filled with polycaprolactone (PCL) was explored in the current experiment. DO conditions in the influent of the denitrifying reactors were set up as follows: the anoxic treatment group (Group A, average DO concentration of 0.28±0.05mg/L), the low-oxygen treatment DO group (Group B, average DO concentration of 2.50±0.24mg/L) and the aerated treatment group (Group C, average DO concentration of 5.63±0.57mg/L). Feeding with 200mg/L of NO3(-)-N, the NO3(-)-N removal rates were 1.53, 1.60 and 1.42kg/m(3) PCL/day in Groups A, B and C, respectively. No significant difference in NO3(-)-N removal rates was observed among the three treatments. It was concluded that the inhibitory effects of DO concentrations lower than 6mg/L on heterotrophic denitrification in the fixed-film reactors filled with PCL can be mitigated. PMID:27155419

  15. Effects of Support on the Performance of NiO-Based Oxygen Carriers Effets du support sur les performances de matériaux transporteurs d’oxygène à base d’oxyde de nickel

    Directory of Open Access Journals (Sweden)

    Baek J.-I.


    Full Text Available The performance of an oxygen carrier for Chemical Looping Combustion varies with the support material used. NiO oxygen carriers were prepared using 60 or 70 wt% NiO and different raw support materials (γ-Al2O3, pseudoboehmite, α-Al2O3, γ-Al2O3 mixed with MgO, hydrotalcite, MgAl2O4, and γ-Al2O3 with added graphite by the mechanical mixing method. Reactivity tests were conducted using a thermogravimetric analyzer (TGA at 950˚C. The oxygen carriers prepared using γ-Al2O3, γ-Al2O3 mixed with a small amount of MgO, hydrotalcite, and MgAl2O4 showed high oxygen transfer capacity, high oxygen utilization, and a high oxygen transfer rate. Graphite addition to γ-Al2O3 did not increase the surface area or reactivity. The use of pseudoboehmite as a support led to a significant decrease in oxygen transfer capacity and severe agglomeration of the oxygen carriers during the redox reaction. The increase in MgO content in the raw support materials decreased the reduction reactivity. The oxygen carriers prepared with α-Al2O3 showed less oxygen transfer capacity than the other oxygen carriers. The differences in the reactivity according to the support type were explained by the relative strength of NiO-support interaction obtained from the temperature-programmed reduction analysis. The reactivity test results in this work indicate that γ-Al2O3 and hydrotalcite could be desirable raw support materials to prepare highly reactive NiO oxygen carriers with high NiO content. Les performances des materiaux transporteurs d’oxygene varient en fonction du support utilise dans le procede de combustion en boucle chimique. Differents materiaux a base d’oxyde de Nickel ont ete synthetises avec des concentrations elevees en NiO, comprises entre 60 et 70 %, sur differents supports (γ-Al2O3, pseudobohemite, α-Al2O3, γ-Al2O3 melangee avec MgO, hydrotalcite, MgAl2O4 et γ-Al2O3 additivees avec du graphite par melange mecanique. Des tests de reactivite ont ete

  16. Synthesis and physicochemical characterization of a series of hemoglobin-based oxygen carriers: objective comparison between cellular and acellular types. (United States)

    Sakai, H; Yuasa, M; Onuma, H; Takeoka, S; Tsuchida, E


    A series of hemoglobin (Hb)-based O(2) carriers, acellular and cellular types, were synthesized and their physicochemical characteristics were compared. The acellular type includes intramolecularly cross-linked Hb (XLHb), polyoxyethylene (POE)-conjugated pyridoxalated Hb (POE-PLP-Hb), hydroxyethylstarch-conjugated Hb (HES-XLHb), and glutaraldehyde-polymerized XLHb (Poly-XLHb). The cellular type is Hb-vesicles (HbV) of which the surface is modified with POE (POE-HbV). Their particle diameters are 7 +/- 2, 22 +/- 2, 47 +/- 17, 68 +/- 24, and 224 +/- 76 nm, respectively, thus all the materials penetrate across membrane filters with 0.4 microm pore size, though only the POE-HbV cannot penetrate across the filter with 0.2 microm pore size. These characteristics of permeability are important to consider an optimal particle size in microcirculation in vivo. POE-PLP-Hb ([Hb] = 5 g/dL) showed viscosity of 6.1 cP at 332 s(-1) and colloid osmotic pressure (COP) of 70.2 Torr, which are beyond the physiological conditions (human blood, viscosity = 3-4 cP, COP = ca. 25 Torr). XLHb and Poly-XLHb showed viscosities of 1.0 and 1.5 cp, respectively, which are significantly lower than that of blood. COP of POE-HbV is regulated to 20 Torr in 5% human serum albumin (HSA). HES-XLHb and POE-HbV/HSA showed comparable viscosity with human blood. Microscopic observation of human red blood cells (RBC) after mixing blood with POE-PLP-Hb or HES-XLHb disclosed aggregates of RBC, a kind of sludge, indicating a strong interaction with RBC, which is anticipated to modify peripheral blood flow in vivo. On the other hand, XLHb and POE-HbV showed no rouleaux or aggregates of RBC. The acellular Hbs (P(50) = 14-32 Torr) have their specific O(2) affinities determined by their structures, while that of the cellular POE-HbV is regulated by coencapsulating an appropriate amount of an allosteric effector (e.g., P(50) = 18, 32 Torr). These differences in physicochemical characteristics between the acellular

  17. Thermoluminescence (TL) properties and x-ray diffraction (XRD) analysis of high purity CaSO4:Dy TL material

    International Nuclear Information System (INIS)

    This paper presents the characterization and TL properties of dysprosium (Dy) doped calcium sulfate (CaSO4) TL material produced by co-precipitation technique with 0.5mol% concentration of dopant. The morphology of the produced TL material was studied using scanning electron microscope (SEM) and the micrograph shows that rectangular parallelepiped shaped crystal with the average of 150 μm in length were produced. The crystallinity of the produced powder was studied using x-ray powder diffraction (XRD). The XRD spectra show that the TL material produced is high purity anhydrite CaSO4 with average crystallite size of 74 nm with orthorhombic crystal system. The TL behavior of produced CaSO4:Dy was studied using a TLD reader after exposure to gamma ray by Co60 source with the doses of 1,5 and 10 Gy. The glow curve shows linear response with glow peak around 230°C which is desired development in the field of radiation dosimetry

  18. Operational experience of electronic active personal dosemeter and comparison with CaSo4:Dy TL dosemeter in Indian PHWR. (United States)

    Singh, Vishwanath P; Managanvi, S S; Bihari, R R; Bhat, H R


    Direct reading dosemeter has been used for day-to-day radiation exposure control and management for last four decades in Indian nuclear power plants (NPPs). Recently new real time, alarm and pre-alarm on equivalent dose/dose rate, storage of dose/dose rate and maximum dose rate, user-friendly electronic active personal dosemeter (APD) has been implemented into practice for the first time at Kaiga Atomic Power Station-3&4,  of Indian NPPs. The dosemeter showed tolerance level (L) 0.1085±0.0450 compared with 0.1869±0.0729 (average±SD) for CaSO4:Dy, TL dosemeter, having narrow range trumpet curve, nil electromagnetic interference. Records of >29 000 for APD and TL dosemeter were analysed for comparasion of the measurement of the individual dose. APD followed general acceptance rule of ±25 % for dose >1 mSv. Monthly Station collective dose by TL dosemeters and APD for normal reactor operation as well as outage are found in good agreement. Operational experiences and statistical analysis support that an APD dosemeter is reasonably equivalent to CaSO4:Dy TL dosemeter. The accuracy, reproducibility and repeatability of the measurement of radiation for (137)Cs are comparable with CaSO4:Dy, TL dosemeter. Operational experience of APD during the normal operation as well as outage showed as one of the best ALARA tool for occupational dose monitoring, control, management and future outage planning. PMID:23528326

  19. Hydrogen and syngas production from two-step steam reforming of methane over CeO2-Fe2O3 oxygen carrier

    Institute of Scientific and Technical Information of China (English)



    Two-step steam reforming of methane(SRM)is a novel chemical looping process towards the production of pure hydrogen and syngas(synthesis gas),consisting ofa syngas production step and a water-splitting step.Renewable energy can be used to drive this process for hydrogen production,especially solar energy.CeO2-Fe2O3 complex oxide oxygen carrier was prepared by the impregnation method and characterized by means of X-ray diffractometer(XRD),Raman spectroscopy(Raman)and hydrogen programmed reduction(H2-TPR).CH4temperature programmed and isothermal reactions were adopted to test syngas production reactivity,and water splitting reaction was employed to investigate water-splitting activity.Moreover,two-step SRM performance was evaluated by a successive redox cycle.The results showed that CO-uncontaminated H2 and highly selective syngas(with H2/CO ratio close to 2)could be respectively obtained from two steps,and CeFeO3 formation was found in the first redox cycle and proved to be enhanced by the redox treatment.After 10 successive cycles,obvious CeFeO3 phase was detected,which may be responsible for favorable successive redox cycle performances.

  20. Effect of solution treatment on Mg galvanic anodes in CaSo4-Mg (OH)2 aqueous solution

    International Nuclear Information System (INIS)

    The effect of heat treatment on the Mg anode was investigated in CaSO4-Mg(OH)2 aqueous solution. The Mg sample was solutionised at 150 degree Celsius, pure and untreated Mg anodes were also studied as a reference. EOC and Tafel corrosion rate was determined by mean of potentiostat. It was found that solution treatment was significantly affecting the performance of Mg anode where it EOC was electro negatively increases to -1.6404 VSCE and the Tafel corrosion rate reduces to 12.23 mpy. (author)

  1. Low temperature dosimetry in LiF: Mg, Cu, P and CaSO4: Dy doped crystals

    International Nuclear Information System (INIS)

    It is presented a behavior study of LiF solid dosemeters doped with Mg, Cu and P also polycrystalline samples of CaSO4 with Dy sinterized in laboratory, both of them were subjected at low temperature. In order to analyse linear behavior to the dose of these dosemeters, it was used thermoluminescence. These materials were exposed to gamma radiation coming from a Co-60 source. The samples were irradiated at dose rates 1.08 ± 0.01 Gy/min at liquid nitrogen temperature (LNT) and also the response of dosemeters are compared at ambient temperature and LNT. (Author)

  2. Simultaneos determination of absorbed doses due to beta and gamma radiations with CaSO4: Dy produced at Ipen

    International Nuclear Information System (INIS)

    Due to the Goiania radiological accident, it was necessary to develop urgently a dosimeter in order to evaluate, simultaneously, beta and gamma absorbed doses, due to 137Cs radiations. Therefore, the Dosimetric Material Production Laboratory of IPEN developed a simple, practical, light and low cost badge using small thickness (0,20mm) thermoluminescent CaSO4: Dy pellets produced by the same laboratory. This pellets are adequate for beta radiation detection. These dosimeters were worn by some IPEN technicians who worked in Goiania city, and were used to evaluate the external and internal contaminations presented by the accident victims interned at the Hospital Naval Marcilio Dias. (author)

  3. Development of quality assurance procedures for thermoluminescent CaSO4:Dy-teflon skived tape dosemeter

    International Nuclear Information System (INIS)

    CaSO4:Dy-Teflon TLD dosemeter material has been manufactured locally in a 0.4 mm thick continuous tape form. Fourteen batches have been examined for physical thickness, density, spectral transmission, diffuse optical density, beta transmission and TL output per unit area for evolving a procedure for quality assurance of the TLD element for large scale production. With the exception of two batches, the TL output per unit area of the tape for a number of batches lies within ±7% of that for a standard batch. (author)

  4. Operational experience with a system of coupled fluidized beds for chemical looping combustion of solid fuels using ilmenite as oxygen carrier

    International Nuclear Information System (INIS)

    Highlights: • Successful operation of a coupled fluidized bed system for CLC of coal. • Two-stage design worked well, i.e. the 2nd stage has an significant effect on fuel conversion. • Solids circulation rates were determined. • High carbon capture rate (ηCC > 96%), which might be attributed to the very fine coal. - Abstract: A system of coupled fluidized beds for chemical looping combustion of solid fuels was successfully commissioned. The facility has a rated thermal power of 25 kW and consists of a circulating fluidized bed coupled with a two-stage bubbling fluidized bed. The two-stage bubbling fluidized bed is the fuel reactor and the riser of the circulating fluidized bed is the air reactor. In the experiments Australian ilmenite with a particle size in the range of 100–400 μm was used as the oxygen carrier. The solid fuel was lignite dust with more than 70% of the mass having a particle size smaller than 150 μm. The influence of the operational parameters, i.e. reactor temperature, coal feed rate and composition of the fuel reactor feed gas on the operational behaviour of the system was investigated. The two-stage fuel reactor performed well and CO2-concentrations in the dry fuel reactor off-gas of above 90 vol.% were achieved. The reason for the appearance of unconverted combustible gases in the fuel reactor off-gas needs further investigation. Solids circulation rates based on the riser cross-section were determined under hot operating conditions and turned out to be between 56 and 70 kg/m2 s. The carbon slip to the air reactor was small in all tests: only 1.5–6.5 wt.% of the fixed carbon introduced with the coal were oxidized in the air reactor

  5. Hydration of calcium sulfate hemihydrate (CaSO 4· {1}/{2}H 2O) into gypsum (CaSO 4·2H 2O). The influence of the sodium poly(acrylate)/surface interaction and molecular weight (United States)

    Boisvert, Jean-Philippe; Domenech, Marc; Foissy, Alain; Persello, Jacques; Mutin, Jean-Claude


    The retarding influence of sodium poly(acrylate) (PANa) on the hydration of calcium sulfate hemihydrate (CaSO 4· {1}/{2}H 2O) was investigated. This study reports the influence of sodium poly(acrylate) on hemihydrate dissolution, on homogenous and heterogeneous gypsum (CaSO 4·2H 2O) nucleation as well as on gypsum growth. It is shown that adsorption of PANa does not hinder the dissolution of hemihydrate in the present experimental conditions. The specific interaction of PANa with gypsum can explain the oriented growth of gypsum crystal. The gypsum growth is slowed down but cannot be blocked by the adsorption of PANa. On the other hand, PANa can block the heterogeneous and homogenous gypsum nucleation. As soon as a critical surface density of PANa onto the hemihydrate surface is reached, the heterogeneous gypsum nucleation is prevented and hemihydrate hydration is indefinitely blocked. The interaction between PANa and the hemihydrate surface is of prime importance to control hydration. Also, the influence of the molecular weight of PANa on homogenous nucleation has been investigated. The precipitation of calcium polyacrylate can explain the differences between the two molecular weights used (2100 and 20 000). This work leads to the conclusion that heterogeneous nucleation is the key process that controls hydration of a system in which hemihydrate dissolution, gypsum nucleation and growth are all occurring at the same time in a continuous manner.

  6. Optimizing a method to obtain CaSO4 activated with Dy for use in thermoluminescent dosimetry

    International Nuclear Information System (INIS)

    Results obtained from experiments in optimizing the variables in the preparation of CaSO4 activated with dysprosium, as phosphors to be used as low dose TL dosemeters for routine radiological protection are presented. The technique used combined those of T. Yamashita and of K. Becker. Heating 8.6 gm of CaSO4.H2O with 0.1 mol % of Dy2O3 in 115 ml of concentrated H2SO4 to 2850C to completely evaporate the acid and placing the obtained crystals in a 6000C oven for one hour gave a TL dosimeter with a sensitivity sufficient to measure 5 mR of 60Co gamma radiation and show a lineal response with this radiation in a 5 mR-5x104R interval. Fading, which appeared in the phosphor only after three weeks, was in the fourth week 4.0% and in the eighth week 6.2% with a σ=+-2.1%. The quality of the phosphor obtained and its ease of reproducibility deserves note. (author)

  7. Thermoluminescent characteristics of LiF:Mg,Cu,P and CaSO$_4$:Dy for low dose measurement

    CERN Document Server

    Fernández, S Del Sol; Mendoza, J Guzmán; Sánchez-Guzmán, D; Rodríguez, G Ramírez; Gaona, E; Montalvo, T Rivera


    Thermoluminescence (TL) characteristics for LiF:Mg,Cu,P, and CaSO$_4$:Dy under the homogeneous field of X-ray beams of diagnostic irradiation and its verification using thermoluminescence dosimetry is presented. The irradiation were performed utilizing a conventional X-ray equipment installed at the Hospital Ju\\'arez Norte of M\\'exico. Different thermoluminescence characteristics of two material were studied, such as batch homogeneity, glow curve, linearity, detection threshold, reproducibility, relative sensitivity and fading. Materials were calibrated in terms of absorbed dose to the standard calibration distance and they were positioned in a generic phantom. The dose analysis, verification and comparison with the measurements obtained by the TLD-100 were performed. Results indicate that the dosimetric peak appears at 202$^o$C and 277.5$^o$C for LiF:Mg,Cu,P and CaSO$_4$:Dy, respectively. TL response as a function of X-ray dose showed a linearity behavior in the very low dose range for all materials. However...

  8. Measurement of the dose by dispersed radiation in a lineal accelerator using thermoluminescent dosimeters of CaSO4:Dy

    International Nuclear Information System (INIS)

    The thermoluminescence (Tl) is based on the principle of the luminescent in a material when is heated below their incandescence temperature. Is a technique very used in dosimetry that is based on the property that have most of the crystalline materials regarding the storage of the energy that they absorb when are exposed to the ionizing radiations. When this material has been irradiated previously, the radioactive energy that contains is liberated in form of light. In general, the principles that govern the thermoluminescence are in essence the same of those responsible for all the luminescent processes and, this way, the thermoluminescence is one of the processes that are part of the luminescence phenomenon. For this work, the dispersed radiation was measured in the therapy area of the lineal accelerator of medical use type Elekta, using thermoluminescent dosimeters of CaSO4:Dy + Ptfe developed and elaborated in the Universidad Autonoma Metropolitana, Unidad Iztapalapa. With the dosimeters already characterized and calibrated, we proceeded to measure the dispersed radiation being a patient in treatment. The results showed values for the dispersed radiation the order of a third of the dose received by the patient on the treatment table at 30 cm of the direct beam and the order of a hundredth in the control area (4 m of the direct beam, approximately). The conclusion is that the thermoluminescent dosimeters of CaSO4: Dy + Ptfe are appropriate to measure dispersed radiation dose in radiotherapy. (author)

  9. Phosphor plasters of CaSO4:Dy on the courtyard wall of Djehuty's tomb (Luxor, Egypt)

    International Nuclear Information System (INIS)

    The X-ray diffraction (XRD) and environmental scanning electron microscopy (ESEM) analyses of plasters collected from the courtyard walls of Djehuty's tomb show anhydrite, calcite, dolomite, quartz, alkali feldspars and accessorial amounts of halite and illite. The external outer bed is mainly composed by anhydrite, since the original hydrous phases of gypsum plaster were desiccated during thirty centuries in the dry land environment of the Luxor area, under low relative humidity and high temperatures. The luminescence analyses by thermoluminescence (TL) and cathodoluminescence (CL) demonstrate as one plaster sample (m8), i.e., 95% anhydrite, displays a gigantic TL emission of 33 555 a.u. and a SEM/CL emission of 2319 a.u. maxima peak. The spectra CL also exhibits a 484 nm peak attributable to the classic 4F9/2→6H15/2 transition circa 490 nm of Dy3+ and a 573 nm emission of Dy3+ masked in a broad emission band centered at 620 nm. The common presence of sodium minerals such as halite or albite together with the probable presence of sodium in waters points to Na+ ions acting as compensators of Dy3+ to maintain the electrical neutrality of the CaSO4:Dy phosphor lattice. Further analyses of more plaster CaSO4 micro-samples could demonstrate if this observation is just an isolated mineralogical chance or an intentional archaeological handling

  10. Dosimetric properties of a new high sensitive CaSO4:Dy thermostimulated luminescent phosphor and teflon discs

    International Nuclear Information System (INIS)

    This paper describes the dosimetric properties of a high sensitive CaSO4:Dy thermostimulated luminescence (TLD) phosphor (called N) and Teflon discs supplied by M/s Fluorokraft. The average grain size of this phosphor is very low (10 to 20 μm). Scanning electron microscope photograph reveals needle shaped crystals while that of CaSO4:Dy prepared by the presently used recrystallization technique (called P) is featureless. The TSL sensitivity of N (4 Gy, P exhibits drastic glow curve changes at dose levels ≥ 10 Gy. As a result, the supralinearity of N > 10 Gy is considerably less than that of P. The TSL and photoluminescent (PL) emission spectra show the characteristic 480 and 570 nm Dy3+ lines in both the samples but their relative intensity ratio seem to be sample dependent. In contrast to TSL, the PL intensity of N is just 1/5th that of P. Electron spin resonance and x-ray diffraction studies also show differences between the two samples. (author)

  11. Effects of Partial Substitutions of NaCl with KCl, CaSO4 and MgSO4 on the Quality and Sensorial Properties of Pork Patties (United States)

    Chun, Ji-Yeon; Cho, Hyung-Yong; Min, Sang-Gi


    This study investigated the effects of NaCl replacers (KCl, CaSO4, and MgSO4) on the quality and sensorial properties of pork patty. In the characteristics of spray-dried salt particles, KCl showed the largest particle size with low viscosity in solution. Meanwhile CaSO4 treatment resulted in the smallest particle size and the highest viscosity (p<0.05). In comparison of the qualities of pork patties manufactured by varying level of Na replacers, MgSO4 treatment exhibited low cooking loss comparing to control (p<0.05). Textural properties of KCl and MgSO4 treatments showed similar pattern, i.e., low level of the replacers caused harder and less adhesive texture than those of control (p<0.05), whereas the hardness of these products was not different with control when the replacers were added more than 1.0%. The addition of CaSO4 also manifested harder and less adhesive than control (p<0.05), but the textural properties of CaSO4 treatment was not affected by level of Ca-salt. Eventually, sensorial properties indicated that KCl and CaSO4 influenced negative effects on pork patties. In contrast, MgSO4 showed better sensorial properties in juiciness intensity, tenderness intensity as well as overall acceptability than control, reflecting that MgSO4 was an effective Na-replacer in meat product formulation. PMID:26761288

  12. Heat capacities and entropies from 8 to 1000 K of langbeinite (K2Mg2(SO4)3), anhydrite (CaSO4) and of gypsum (CaSO4·2H2O) (United States)

    Robie, Richard A.; Russell-Robinson, Susan; Hemingway, Bruce S.


    Heat capacities of K2Mg2(SO4)3 (langbeinite) and CaSO4 (anhydrite) were measured from approximately 8 to 1000 K by combined adiabatic shield calorimetry (8-365 K) and differential scanning calorimetry (350-1000 K). Heat capacities were also measured on natural crystals of gypsum (CaSO4 · 2H2O) between 8.1 and 323.5 K. The molar entropies at 298.15 K, Smo(298.15 K), are 378.8 ± 0.6, 107.4 ± 0.2 and 193.8 ± 0.3 J K−1 mol−1 for langbeinite, anhydrite and gypsum, respectively. The heat capacity in J K−1 mol−1 of langbeinite can be represented by the equation Cp,mo(K2Mg2(SO4)3T) = 535.9 + 0.11011T-1.0200 × 106/T2-4.909 × 10−5T2 -4040.2/T0.5 between 300 and 1000 K with an average deviation of ± 0.4%. For anhydrite the heat capacity between 300 and 1000 K is given by Cp,mo(CaSO4,T) = 372.8 - 0.1574 T +1.695 × 106/T2 + 7.993 × 10−5T2 - 4330.8/T0.5 with an average deviation of ±0.4%.

  13. Simulation Experiments on the Reaction of CH4-CaSO4 and Its Carbon Kinetic Isotope Fractionation

    Institute of Scientific and Technical Information of China (English)

    YueChangtao; LiShuyuan; DingKangle; ZhongNingning


    Thermochemical sulfate reduction (TSR) in geological deposits can account for the accumulation of H,S in deep sour gas reservoirs. In this paper, thermal simulation experiments on the reaction of CH4-CaSO4 were carried out using an autoclave at high temperatures and high pressures. The products were characterized with analytical methods including carbon isotope analysis. It is found that the reaction can proceed to produce H2S, H2O and CaCO3 as the main products. Based on the experimental results, the carbon kinetic isotope fractionation was investigated, and the value of Ki(kinetic isotope effect) was calculated. The results obtained in this paper can provide useful information to explain the occurrence of H2S in deep carbonate gas reservoirs.


    CERN Document Server

    Otto, T; Gindraux, L


    The intrinsic thermoluminescence (TL) efficiency of a TL detector relates the absorbed dose in the detector material to the light yield observed upon evaluation. Knowledge of the TL efficiency is of interest when performing numerical simulations of detector response, where only absorbed dose can be predicted. Here, the experimental determination of TL efficiency for calcium sulphate (CaSO(4):Tm) and lithium borate (Li(2)B(4)O(7):Cu) is reported. These materials are widely used in Panasonic dosemeter badges. The results of the study are in agreement with predictions from track structure theory and microdosimetry, relating an enhanced light yield at low X-ray energies to supralinear behaviour of the TL phosphor.

  15. Testing of CaSO-4:Dy in teflon discs as a thermoluminescent dosimetry material for personal monitoring of uranium mine and mill workers

    International Nuclear Information System (INIS)

    Some studies of the spectroscopic and thermoluminescent properties of CaSO4:Dy are discussed. Measurements were also made in the field. Exposures measured using TLD, film and spot monitoring were in agreement, and these observations, together with measurements made at various heights above the ore stockpile have shown that CaSO4:Dy in teflon discs, shielded by 2mm of copper, give a reliable measure of the exposure at the appropriate position on the wearer's body. This exposure may then be converted into the dose equivalent for the whole body

  16. Study on the Development and Dosimetric Properties of New CaSO4:Dy TL Detectors Bonded by P-compounds for Gamma, Beta and Neutron Measurement

    International Nuclear Information System (INIS)

    A thermoluminescence dosimeter (TLD) has been generally accepted as the most accurate and reliable method of personal dosimetry because of its superior and long term stability comparing with other type dosimeter, such as Film Badge. Among many TL (thermoluminescence) materials investigated and suggested so far, the CaSO4:Dy TL material has been most widely used as a personal or environmental dosimeter because of its high sensitivity and low fading. A solid or crystalline form dosimeter is generally preferred for routine dosimetric applications since it has an advantage of handling convenience over the loose TL powder. For this reason, sintered TL pellets are usually used. However a difficulty is still in manufacturing the dosimeter in the form of sintered pellets in which the TL characteristics of original powder remain unchanged. It is not possible to make a solid dosimeter composed of 100 % pure CaSO4:Dy TL powder. One of the most frequent methods is mixing CaSO4:Dy TL powder with binding substances. A Teflon is a good binding material currently used because it does not change the TL characteristics of CaSO4:Dy TL powder. In the case of the Teflon pellet, due to the reduction of CaSO4:Dy powder content by 15 ∼ 20 wt% in TL pellets, the TL sensitivity of the Teflon pellet accordingly decreases, and moreover the re-usability of this Teflon pellet is not sufficient due to its color changing. To overcome this disadvantage, many researchers have prepared CaSO4:Dy TL pellets by mixing the powder with different binding substances. But even with these efforts, they could not significantly improve the TL intensity and other TL characteristics required for radiation dosimeter. In Korea, studies on the development of high sensitivity TL pellet using CaSO4:Dy TL material have been conducted in Korea Atomic Energy Research Institute (KAERI). This thesis presents the development of CaSO4:Dy TL pellet by bonding the TL powder with small amount of P-compounds designated as KCT-300 (KAERI CaSO4:Dy TLD). Dosimetric properties of the KCT-300 TL dosimeter have been investigated by using the method presented in the IEC 1066 international Standard. The sensitivity of the KCT-300 was about 6 times higher than that of the Teflon CaSO4:Dy TL dosimeter (Teledyne, USA). The dose response of KCT-300 was linear over the range from 10-5 Gy to 10 Gy and supralinear at higher dose. The energy response of the KCT-300 has been also investigated for photon energies from 20 keV to 663 keV. The result of strong energy dependence below 100 keV is attributed to the high effective atomic number of CaSO4. Hence, when the CaSO4:Dy pellet is used for a personnel dosimeter, energy-compensation filters should be considered for the low energy region. The coefficients of variation for KCT-300 did not exceed 0.075, which the IEC requires as a standard value. This means that reproducibility of the KCT-300 well satisfies the IEC requirements. The lower limit of detection (LLD) of the KCT-300 was 0.6 μ Gy, which was measured by Harshaw 4500 TLD Reader. When CaSO4:Dy TL material is used to measure the thermal neutron, it cannot be directly applied to the thermal neutron dosimeters in spite of its good TL characteristics because the thermal neutron capture cross section of the constituents of CaSO4:Dy is small. One method to enhance the neutron interaction is obtained by introducing an element of 6Li into TL powder because 6Li has a large thermal neutron capture cross section and acts as a neutron absorption centre. Several studies for thermal neutron dosimetry using CaSO4:Dy TLD have been performed so far. Most of the neutron dosimetry results reported in the literature have been obtained by using powder type CaSO4:Dy TL dosimeters rather than pellet type dosimeters. In this thesis a development of pellet type TL dosimeters for neutron measurement, designated as KCT-306 has been presented. If a 6Li-compound is embedded in CaSO4:Dy TL phosphor as a thermal neutron absorption material, α particle and 3H particle are produced via the 6Li(n,α)3H reaction when exposed to thermal neutron, and their energies are absorbed by the CaSO4:Dy TL phosphor to produce a TL. The TL pellets combination of our KCT-306/KCT-300, the commercially avaliable TLD-600/TLD-700, and TLD-600H/TLD-700H (Harshaw, USA) have been irradiated in the neutron/gamma mixed fields of a D2O moderated (30 cm dia.) 252Cf neutron source in KAERI. The TLD-700, TLD-700H and KCT-300 were used at the same time for gamma ray discriminators in the neutron/gamma mixed fields. It was found that the neutron/gamma response ratio of KCT-306/KCT-300, which is developed in this study, was about 4 times higher than that of the commercial TLD-600/TLD-700 or TLD-600H/TLD-700H. This means that the KCT-306 in combination with KCT-300 could be used as a thermal neutron dosimeter in a mixed radiation field. The TL materials KCT-300 and KCT-306 developed in this study could be utilized in a more precise measurement and evaluation of the personal as well as environmental radiation doses by using TLD



    Krtolica, A; Le Moan, N.; Serwer, L.; Yoshida, Y.; Ozawa, T; Butowski, N.; James, D; Cary, S.


    We have developed OMX-4.80, a tunable oxygen carrier from the H-NOX protein family, that preferentially accumulates in tumor tissue, reduces hypoxia and enhances radiotherapy (RT). Tumor hypoxia is associated with poor patient outcomes in multiple solid tumors including glioblastoma (GB) and is thought to be a major contributor to poor cancer responses to chemo and radiation therapy. Here, we show that OMX-4.80 administered i.v. into the tail vein of mice bearing orthotopic GB passes the bloo...

  18. Forecasting of phase equilibriums in the K, Mg, Ca//SO4, Cl-H2O system by translation method

    International Nuclear Information System (INIS)

    The purpose of this work is constructing of diagrams of phase equilibriums of five-component K, Mg, Ca//SO4, Cl-H2O system, composing its four-component systems by translation method and elaboration of proposals on reprocessing of potassium-magnesium-calcium chloride-sulfate raw materials

  19. A comparative study of thermoluminescent properties of CaSO4:Dy+PTFE and TLD-110 irradiated with X-ray

    International Nuclear Information System (INIS)

    This paper presents the results of studying the thermoluminescent (TL) properties of CaSO4:Dy+PTFE and TLD-100 when they are exposed to X-rays in the range from 60 to 300 kV with a mean energy ranged from 48 to 250 keV. The CaSO4:Dy+PTFE glow curve exhibited two peaks at 200 and 290 deg C with the maximum emission at the first peak. Its TL response as a function of dose was linear in the range from 0.25 up to 5 Gy. The TL response of both materials as a function of photon energy was also investigated. The CaSO4:Dy+PTFE showed the same glow curve at different energies exhibiting the main peak centered on 200 deg C and variable sensitivity as a function of energy. These results showed that CaSO4:Dy+PTFE has potential to be used as a TL dosimeter for X-rays in the range of energies used in radiation diagnosis. (author)

  20. Radionuclide carriers

    International Nuclear Information System (INIS)

    A new carrier for radionuclide technetium 99m has been prepared for scintiscanning purposes. The new preparate consists of physiologically acceptable water-insoluble Tcsup(99m)-carrier containing from 0.2 to 0.8 weight percent of stannic ion as reductor, bound to an anionic starch derivative with about 1-20% of phosphate substituents. (EG)

  1. Aircraft Carriers

    DEFF Research Database (Denmark)

    Nødskov, Kim; Kværnø, Ole

    the majority of its foreign trade, as well as its oil imports, upon which the country is totally dependent. China therefore has good reasons for acquiring an aircraft carrier to enable it to protect its national interests. An aircraft carrier would also be a prominent symbol of China’s future status...... information is pieced together, then a picture is created of a Chinese aircraft carrier program, where Varyag will be made operational for training purposes. With this as the model, China will build a similar sized carrier themselves. If this project does become a reality, then it will take many years for...... Kuznetsov carrier. The SU-33 is, in its modernized version, technologically at the same level as western combat aircraft in both the offensive as well as the defensive roles. But Russia and China currently have an arms trade 6 dispute that is likely to prevent a deal, unless the dispute is resolved. As an...

  2. The effect of heating rate on the dose dependence and thermoluminescence characteristics of CaSO4: Dy (TLD-900)

    International Nuclear Information System (INIS)

    Highlights: • The effect of heating rate on the dose dependence of TLD-900 has been investigated by using f(D) function at different linear heating rates. • The experimental results have shown that the linearity of the main dosimetric peak continues nearly up to 100 Gy at heating rates of 3 oC/s and 5 oC/s. • The peak temperatures are shifted higher temperatures as the heating rate increases. • The integrated peak area of the curves decreases by about 50% as the heating rate increases. - Abstract: CaSO4: Dy (TLD-900) is a well-known phosphor for radiation dosimetry using thermoluminescence. In the given study, the effect of heating rate on the dose dependence and thermoluminescence characteristics of TLD-900 has been investigated by using the dose response function f(D) at different linear heating rates. It was observed that, the peak temperature of the main dosimetric glow peak (P2) shifts to higher temperature sides and the integrated peak area decreases by about 50% as the heating rate increases due to thermal quenching

  3. Dosimetric intercomparison in Cobalt 60 unities using TLD-100 crystals and CaSO4: Dy + Ptfe

    International Nuclear Information System (INIS)

    The purpose of this work is to design and construct a phantom in basis of thermoplastic polymer of methyl methacrylate that is reutilizable and which allows to do an analysis of the absorbed doses in thermoluminescent crystals (Tl) exposed to cobalt 60 to establish the dosimetric intercomparison in cobalt units which allows to do the follow-up of the Quality assurance programs, standardization of calibration procedures, dosimetry and TLD post intercomparison in radiotherapy. This work allows also prove new thermoluminescent materials of national manufacture developed by Juan Azorin and collaborators as the CaSO4: Dy + Ptfe. This is a first study which is realized in Mexico with the system crystal-phantom for aims to intercomparison in cobalt 60 units. In this work participate eight unities of cobalt 60 of different trades belonging at four radiotherapy centers. The results of the dose intercomparison of the eight unities of cobalt 60 were in the range 0.95-1.13, taking in account that the values between 0.95 and 1.05 were considered acceptable in terms of the requirements by the standing legislation. (Author)

  4. Characterization and standardization of a thermoluminescent dosimetric system to ultraviolet and laser radiation using CaSO4:Dy

    International Nuclear Information System (INIS)

    The photo transferred thermoluminescence (PTTL) was used to characterize a dosimetric system to the laser and ultraviolet radiation. Dysprosium activated calcium sulphate samples (CaSO4:Dy) used are produced at Instituto de Pesquisas Energeticas e Nucleares (IPEN) and have proved been an excellent dosimetric material for non ionizing radiation. PTTL signal was studied for UV radiation detection in the 220 to 450 nm range and for laser radiation in the 193 to 1.160 nm range. The samples presented more sensibility to the 193, 250, 310 and 337 nm wavelengths and no sensibility to infrared region. The samples presented linear PTTL in function of radiant exposure, excitation gamma dose in the range between 5 and 100 Gy and laser beam diameter between 2 and 6 nm. Another parameters studied were the angular dependence, UV lower exposure limit and PTTL signal optical fading. Spread laser radiation analysis was performed in the Ophthalmologic Department of Universidade Federal de Sao Paulo (UNIFESP) surgical center, showing that samples positioned as far as 4 m from laser source are sensitized to the laser radiation, as well as evaluating the laser exposure received by workers of medical area. A method to send the samples by mail was developed to the studies performed in the UNIFESP. (author)

  5. Triplicate genes for mitochondrial ADP/ATP carriers in the aerobic yeast Yarrowia lipolytica are regulated differentially in the absence of oxygen

    DEFF Research Database (Denmark)

    Mentel, M.; Piskur, Jure; Neuveglise, C.; Rycovska, A.; Cellengova, G.; Kolarov, J.


    Yarrowia lipolytica is a strictly aerobic fungus, which differs from the extensively studied model yeasts Saccharomyces cerevisiae and Schizosaccharomyces pombe with respect to its physiology, genetics and dimorphic growth habit. We isolated and sequenced cDNA and genomic clones (YlAAC1) from Y....... lipolytica that encode a mitochondrial ADP/ATP carrier. The YlAAC1 gene can complement the S. cerevisiae Delta aac2 deletion mutant. Southern hybridization, analysis of Yarrowia clones obtained in the course of the Genolevures project, and further sequencing revealed the existence of two paralogs of the Yl...

  6. Aircraft Carriers

    DEFF Research Database (Denmark)

    Nødskov, Kim; Kværnø, Ole

    as a great power in Asia and will balance the carrier acquisitions of the United States, the United Kingdom, Russia and India. China’s current military strategy is predominantly defensive, its offensive elements being mainly focused on Taiwan. If China decides to acquire a large carrier with...... offensive capabilities, then the country will also acquire the capability to project military power into the region beyond Taiwan, which it does not possess today. In this way, China will have the military capability to permit a change of strategy from the mainly defensive, mainland, Taiwan-based strategy...... to a more assertive strategy, with potentially far-reaching consequences for the countries of the region. The Chinese have bought several retired carriers, which they have studied in great detail. The largest is the Russian-built carrier Varyag of the Kuznetsov class, which today is anchored in the...

  7. Bioconjugation of Serum Albumin to a Maleimide-appended Porphyrin/Cyclodextrin Supramolecular Complex as an Artificial Oxygen Carrier in the Bloodstream. (United States)

    Kitagishi, Hiroaki; Kawasaki, Hiroki; Kano, Koji


    HemoCD is an inclusion complex of per-O-methylated β-cyclodextrin dimer and an iron(II) porphyrin, which forms a stable O2 complex in water. Therefore, hemoCD has the potential for use as a synthetic O2 carrier in mammalian blood. In this study, a hemoCD derivative having a maleimide group (Mal-hemoCD) was conjugated to a Cys residue of serum albumin via a Michael addition reaction in order to increase the circulation time of the O2 carrier. The O2 -binding affinities (P1/2 [Torr]) and half-lives (t1/2 [h]) of the O2 adducts at pH 7.4 and 25 °C were determined to be 9 Torr and 23 h for Mal-hemoCD, and 10 Torr and 14 h for albumin-conjugated hemoCD (Alb-hemoCD). Our pharmacokinetic study revealed that renal excretion of Alb-hemoCD was effectively suppressed and that half of injected Alb-hemoCD remained in blood at 3 h after injection. It is noteworthy that Mal-hemoCD also had a long circulation time because of the bioconjugation reaction that occurred during circulation in the bloodstream. PMID:26053595

  8. An In Vitro Comparison of PMMA and Calcium Sulfate as Carriers for the Local Delivery of Gallium(III) Nitrate to Staphylococcal Infected Surgical Sites. (United States)

    Garcia, Rebecca A; Tennent, David J; Chang, David; Wenke, Joseph C; Sanchez, Carlos J


    Antibiotic-loaded bone cements, including poly(methyl methacrylate) (PMMA) and calcium sulfate (CaSO4), are often used for treatment of orthopaedic infections involving Staphylococcus spp., although the effectiveness of this treatment modality may be limited due to the emergence of antimicrobial resistance and/or the development of biofilms within surgical sites. Gallium(III) is an iron analog capable of inhibiting essential iron-dependent pathways, exerting broad antimicrobial activity against multiple microorganisms, including Staphylococcus spp. Herein, we evaluated PMMA and CaSO4 as carriers for delivery of gallium(III) nitrate (Ga(NO3)3) to infected surgical sites by assessing the release kinetics subsequent to incorporation and antimicrobial activity against S. aureus and S. epidermidis. PMMA and to a lesser extent CaSO4 were observed to be compatible as carriers for Ga(NO3)3, eluting concentrations with antimicrobial activity against planktonic bacteria, inhibiting bacterial growth, and preventing bacterial colonization of beads, and effective against established bacterial biofilms of S. aureus and S. epidermidis. Collectively, our in vitro results indicate that PMMA is a more suitable carrier compared to CaSO4 for delivery of Ga(NO3)3; moreover they provide evidence for the potential use of Ga(NO3)3 with PMMA as a strategy for the prevention and/or treatment for orthopaedic infections. PMID:26885514

  9. TL and EPR studies of CaSO4:Dy phosphor to investigate its efficacy in measurement of food irradiation dose at sub-ambient temperatures

    International Nuclear Information System (INIS)

    The effects of sub-ambient temperatures of irradiation and dose response of CaSO4:Dy phosphor was investigated. The irradiation dose in the range 0.5-7.0 kGy was chosen to meet the requirement of commercial food irradiation at low temperature. Commercially available phosphor showed no significant change in glow curve structure with low temperature of irradiation. In order to enhance the sensitivity of the low temperature glow peak (142 oC), the phosphor was subjected to different post-preparation thermal treatments at 700-900 oC. The change in glows and improvement in dose response characteristics were explained by Electron Paramagnetic Resonance (EPR) spectroscopy. At sub-ambient temperature of irradiation, the behavior of thermally treated CaSO4:Dy phosphor with increasing dose revealed improved linear response of the low temperature glow peak and could be an efficient dosimetry system for the food commodities irradiated at low temperatures.

  10. Triplicate genes for mitochondrial ADP/ATP carriers in the aerobic yeast Yarrowia lipolytica are regulated differentially in the absence of oxygen

    DEFF Research Database (Denmark)

    Mentel, M.; Piskur, Jure; Neuveglise, C.;


    phylogenetic tree, suggesting that YlAAC3 is derived from a more ancient duplication within the Y. lipolytica lineage. A similar branching pattern for the three ScAAC paralogs in the facultative anaerobe S. cerevisiae demonstrates that two rounds of duplication of AAC genes occurred independently at least......AAC1 gene, which were named YlAAC2 and YlAAC3, respectively. Phylogenetic analysis showed that YlAAC1 and YlAAC2 were more closely related to each other than to YlAAC3, and are likely to represent the products of a recent gene duplication. All three Y. lipolytica YlAAC genes group together on the...... twice in the evolution of hemiascomycetous yeasts. Surprisingly, in both the aerobic Y. lipolytica and the facultative anaerobe S. cerevisiae, the three paralogs are differentially regulated in the absence of oxygen. Apparently, Y. lipolytica can sense hypoxia and down-regulate target genes in response....

  11. A novel oxygen carrier “YQ23” suppresses the liver tumor metastasis by decreasing circulating endothelial progenitor cells and regulatory T cells

    International Nuclear Information System (INIS)

    Surgical therapies are the first-line treatments for hepatocellular carcinoma (HCC) patients. However, the high incidence of tumor metastasis after liver surgery remains a severe problem. We aim to investigate the roles and the underlying mechanism of YQ23, stabilized non-polymeric diaspirin cross-linked tetrameric hemoglobin, in liver tumor metastasis after major hepatectomy and partial hepatic ischemia reperfusion (I/R) injury. An orthotopic liver tumor model in Buffalo rat was established using the hepatocellular carcinoma cell line McA-RH7777. Major hepatectomy for tumor-bearing lobe and partial hepatic I/R injury were performed at two weeks after orthotopic liver tumor implantation. YQ23 (0.2 g/kg) was administered at 1 hour before ischemia and immediately after reperfusion. Blood samples were collected at day 0, 1, 7, 14, 21 and 28 for detection of circulating endothelial progenitor cells (EPCs) and regulatory T cells (Tregs). Our results showed that YQ23 treatment effectively inhibited intrahepatic and lung metastases together with less tumor angiogenesis at 4 weeks after major hepatectomy and partial hepatic I/R injury. The levels of circulating EPCs and Tregs were significantly decreased in YQ23 treatment group. Furthermore, YQ23 treatment also increased liver tissue oxygenation during hepatic I/R injury. Up-regulation of HO1 and down-regulation of CXCR3, TNF-α and IL6 were detected after YQ23 treatment. YQ23 treatment suppressed liver tumor metastasis after major hepatectomy and partial hepatic I/R injury in a rat liver tumor model through increasing liver oxygen and reducing the populations of circulating EPCs and Tregs

  12. Living with Oxygen Therapy (United States)

    ... transportation carrier (for example, the airline or bus company). If you need oxygen while traveling, plan in ... NEXT >> Updated: February 24, 2012 Twitter Facebook YouTube Google+ SITE INDEX ACCESSIBILITY PRIVACY STATEMENT FOIA OIG CONTACT ...

  13. The effect of ultraviolet and visible radiation on the readout obtained from γ-irradiated and unirradiated CaSO4:Dy in teflon discs

    International Nuclear Information System (INIS)

    The effect of ultraviolet and visible radiation on the readout obtained from the main dosimetry peak of CaSO4:Dy in teflon discs is explained by the net result of three separate factors, namely (i) an inherent response, (ii) a phototransfer and (iii) an optical bleaching. Their dependence on wavelength, irradiance and radiant exposure has been studied using a fluorescent light enclosed in a perspex diffuser and a 200W mercury-xenon lamp in conjunction with narrow bandpass filters to isolate specific wavelengths

  14. Oxygen isotopes separation during fluorination of oxygen-containing compounds

    International Nuclear Information System (INIS)

    The mechanisms of separation of oxygen isotopes in the reaction of water with BrF5 and CoF3 and of calcium sulphate with CsBrF4 are considered. The reaction of water with BrF5 is accompanied by enrichment of the oxygen released with the light isotope 16O, and with CoF3, by enrichment with the heavy isotope 18O. The separation of the oxygen isotopes attending the reaction of water with CoF3 is due to the establishment of isotopic equilibrium between the oxygen and the intermediate reaction product, i.e. the hydroderivative of cobalt trifluoride (α=1.016 at 350 deg C). In the case of BrF5 a kinetic isotopic effect takes place (α=0.994sup(*) at 25 deg C and α=0.996 at 120 deg C), which is due to the preferential rupture of the H-16O bond (α is the separation coefficient). The incomplete release of oxygen in the form of O2 from CaSO4 does not lead to separation of the oxygen isotopes, probably becaused of the equivalence of all the peripheral oxygen atoms in the SO4-2 anion from the point of view of the reaction with CsBrF4

  15. Preconception Carrier Screening (United States)

    ... Events Advocacy For Patients About ACOG Preconception Carrier Screening Home For Patients Search FAQs Preconception Carrier Screening ... Screening FAQ179, August 2012 PDF Format Preconception Carrier Screening Pregnancy What is preconception carrier screening? What is ...

  16. Thermoluminescent response to thermal neutrons of mixture of CaSO4: Tm and non-luminous 6LiF

    International Nuclear Information System (INIS)

    Thermoluminescent property of the mixture of CaSO4: Tm powder and non-luminous 6LiF powder was studied with a view to developing a personnel monitor for thermal neutrons. Its thermoluminescent response to thermal neutrons as a function of the particle size or the mixing ratio of both powders was investigated theoretically and experimentally. The phosphor sample, which was prepared according to the most favorable conditions that the particle size of both powders was between 100 -- 150 μm and the mixing weight ratio of CaSO4: Tm to 6LiF was 1 : 1, was found to have the following dosimetric properties. (1) The thermoluminescence output is linear against neutron dose in a dose range from 10 μrem up to 6 rem. (2) The thermoluminescent efficiency remains constant even after 5,000 repetitions of exposure-reading-annealing procedure. (3) A thermal neutron dose of 1 mrem can be determined with a standard deviation of 5.2% even under a γ-ray background of 10 mR. (auth.)

  17. Study of Thermodynamics and Kinetics of CH4-CaSO4 and H2S-Fe2O3 Systems

    Institute of Scientific and Technical Information of China (English)

    岳长涛; 李术元; 丁康乐; 钟宁宁


    The destruction of hydrocarbon in deep carbonate diagenetic environment is one of problems on the formation of oil and gas. Organic-inorganic reactions in the process of TSR(Thermochemical Sulfate Reduction) are the main reason to make disappearance of the hydrocarbons. The work in this field has often been the subject of much research work in recent years. In this paper, the thermodynamics of CH4-CaSO4 and H2S-Fe2O3 systems is discussed to investigate the possibility of reactions. It is found that these two reactions can proceed spontaneously.Increasing temperature is favorite for CH4-CaSO4 system but disfavorite for H2S-Fe2O3 system. Thermal simulation experiments were carried out using autoclave at high temperature and high pressure. The properties of the products were characterized by microcoulometry, FT-IR and XRD methods. On the basis of the experimental data, a reaction kinetic model is developed and kinetic parameters are determined.

  18. Dosimetric properties and stability of thermoluminescent foils made from LiF:Mg,Cu,P or CaSO4:Dy during long-term use

    International Nuclear Information System (INIS)

    A few dosimetric systems based on thermoluminescence [TL] foils were developed in recent years (Nariyama et al. 2006, Radiat. Prot. Dosim. 120, 213–218; Olko et al. 2006 Radiat. Prot. Dosim. 118, 213–218) (Czopyk et al. 2008, Radiat. Meas., 43, 977–980; Kłosowski et al. 2010, Radiat. Meas., 45, 719–721; Kopeć et al. 2013, Radiat.Meas., 56, 380–383). Major application of these systems is mapping of 2D dose distribution for medical treatment plan verification, similarly to photochromic or radiochromic films. The advantage of TL foils compared to other films is their re-usability. In this work we present dosimetric properties as dose linearity and fadding of the foils made from LiF:Mg,Cu,P or CaSO4:Dy phosphors and high temperature polymers. Both types of the foils have good linearity in the range 1–20 Gy for LiF:Mg,Cu,P and 0.1–2 Gy for CaSO4:Dy. Their long term fading does not exceed 3.7% and 9% respectively. We additionally investigated effects of sensitivity loss and emission spectra for both types of the foils. One shortcoming of TL foils is that every heat process may have negative influence on their properties, causing changes of their sensitivity. Register signal of the foils after 15 readouts may be reduced by 16% of the initial. We consider that the main reason of these changes is oxidation of organic contamination on the surface and degradation of a polymer which is one of the components of the foils. Effect of sensitivity decreasing may be slowed down by proper use and cleaning detectors by solvent. - Highlights: • Dosimetric properties of the detectors foils made from LiF:Mg,Cu,P and CaSO4:Dy are present. • Sensitivity loss of the detectors during usage is observed. • 2D detector foils should be cleaned thorough the solvent to increase its use time

  19. 生物质灰对铁矿石载氧体性能的影响%Effect of biomass ash on performance of iron ore as oxygen carrier in chemical looping combustion

    Institute of Scientific and Technical Information of China (English)

    周玉飞; 沈来宏; 顾海明; 牛欣


    在小型固定床上以铁矿石为载氧体、CO为燃料,进行了化学链燃烧试验。通过在铁矿石中加入生物质灰,探讨了生物质灰的种类(玉米秆灰、油菜秆灰和稻草灰)、灰的添加量(5%~20%)及灰中碱金属对铁矿石载氧体反应活性的影响。试验结果表明:生物质灰中无机组分不同,对铁矿石载氧体反应活性的影响也不同。由于玉米秆灰和油菜秆灰中碱金属K含量较高,高温下K以气态形式迁移到铁矿石表面,生成了K3 FeO2,从而提高了铁矿石的还原反应活性。稻草灰中Si含量很高,高温下碱金属K及FeO与铁矿石反应,生成低熔点共晶体,加剧了铁矿石表面的烧结,减少了气固反应的接触面积,导致CO总转化率急剧下降。%Experiment on chemical looping combustion was conducted in a fixed bed reactor with iron ore as oxygen carrier and CO as fuel.The effect of biomass ash addition on the performance of the iron ore oxygen carrier was investigated.Several key factors were discussed, including the bio-mass ash type (corn stalk ash, rape stalk ash, straw ash), the ash ratio (5%to 20%) and the alkali metal in the ash.The results indicate that the effect of the biomass ash on the reactivity of iron ore depends on the chemical composition of the ash.The alkali metal K abundant in corn ash and rape ash is released in gaseous state and captured by iron ore through complicated reactions, forming K3 FeO2 which enhances the reduction reactivity of the iron ore.However, the high content of Si in the straw ash leads to a reaction of Si with K and FeO under high temperature to form low melting point compounds which causes serious sintering on the surface of the iron ore.The decrease of con-tact surface causes the decrease of the total CO conversion.

  20. Oxygen Carriers for Chemical Looping Combustion - 4 000 h of Operational Experience Transporteurs d’oxygène pour la combustion en boucle chimique : expérience accumulée pendant 4 000 h d’opération


    Lyngfelt A.


    Chemical Looping Combustion (CLC) is a new combustion technology with inherent separation of the greenhouse gas CO2. The technology involves the use of a metal oxide as an oxygen carrier which transfers oxygen from combustion air to the fuel, and hence a direct contact between air and fuel is avoided. Two interconnected fluidized beds, a fuel reactor and an air reactor, are used in the process. The outlet gas from the fuel reactor consists of CO2 and H2O, and the latter is easily removed by c...


    Krtolica, A.; Le Moan, N.; Serwer, L.; Yoshida, Y.; Ozawa, T.; Butowski, N.; James, D.; Cary, S.


    We have developed OMX-4.80, a tunable oxygen carrier from the H-NOX protein family, that preferentially accumulates in tumor tissue, reduces hypoxia and enhances radiotherapy (RT). Tumor hypoxia is associated with poor patient outcomes in multiple solid tumors including glioblastoma (GB) and is thought to be a major contributor to poor cancer responses to chemo and radiation therapy. Here, we show that OMX-4.80 administered i.v. into the tail vein of mice bearing orthotopic GB passes the blood-tumor barrier, penetrates deep into intracranial tumors, and significantly reduces tumor hypoxia in a dose-dependent manner. Hypoxia reduction is demonstrated by a significant decrease in levels of hypoxia inducible factor, HIF1α, and the external hypoxia marker pimonidazole as assessed by IHC and image analysis. Furthermore, hypoxia before and after treatment is compared in the individual tumors by concurrent immunostaining of tumors with a long-term hypoxia marker, Glut1, and short-lived HIF-1α. These data reveal >50% reduction in hypoxic tumor area after OMX-4.80 treatment confirming the effectiveness of OMX-4.80 in reducing hypoxia in individual tumors. When OMX-4.80 treatment was coupled with a single high dose of RT, we observed a 2.7-fold increase in tumor growth delay and 2.9-fold longer survival (p < 0.05, by logrank). Toxicology studies in rodents and dogs with single and multiple supratherapeutic doses of OMX-4.80 revealed a good safety profile affirming its suitability for clinical development. In conclusion, our results indicate that OMX-4.80 is an effective and promising RT enhancer that warrants clinical development in GB patients.

  2. Determination of exposure rates from natural background radiation in Khartoum using LiF:Mg,Cu,P (GR-200) and CaSo4: Mn TLD chips

    International Nuclear Information System (INIS)

    The exposure rates from natural background radiation - including terrestrial gamma radiation and the ionizing component of cosmic rays - were measured for the first time in the city of khartoum using two types of TLD materials: LiF:Mg,Cu,P (GR-200) and CaSo4:Mn TLD chips. Measurements were performed at two sites simultaneously, one site was selected on land in the vicinity of the Sudan Atomic Energy Commission, for the purposes of the measurement of the total exposure rate outdoors, while the other site was located on a buoy anchored in the Blue Nile, and was selected to measure the exposure rate due to the ionizing component of cosmic rays. The investigations were conducted for periods of between 5 and 28 days. Calibration was performed on a selected number of dosimeters to determine the exposure rates at each site. The exposure rates from the ionizing component of cosmic rays in Khartoum were found to be respectively 33 nGy.h-1 and 30 nGy.h-1, in the measurements performed within the scope of this work using GR-200 and CaSo4:Mn dosimeters, while the total values for exposure on land were found to be 45 nGy.h-1 and 42 nGy.h-1 respectively. These values compare reasonably well with other national averages reported in the UNSCEAR publication. The comparison of the results for the two dosimetric materials demonstrates both the sensitivity and suitability of GR-200 for the purposes of environmental monitoring (orig.)

  3. 批量制备Fe2O3/Al2O3氧载体及褐煤化学链燃烧实验研究%Batch Preparation of Fe2O3/Al2O3 Oxygen Carriers for Chemical Looping Combustion of Lignite

    Institute of Scientific and Technical Information of China (English)

    郭磊; 赵海波; 马琎晨; 梅道锋; 方彦飞; 郑楚光


    Freeze granulation,spray drying,impregnation and mechanical mixing methods were adopted to prepare Fe2O3/Al2O3 oxygen carriers.To identify the appropriate technologies for batch preparation of the oxygen carriers,the four preparation methods were compared in terms of yield rate,preparation period,physical and chemical characteristics and performance in chemical looping combustion (CLC) of lignite.The experimental results show that freeze granulation has the highest yield rate of carrier with the best mechanical strength.CLC tests of lignite demonstrate that the oxygen carriers prepared by freeze granulation and spray drying bring the highest carbon conversion rate,followed by impregnation and mechanical mixing; and the oxygen carriers prepared by the first two methods have higher chemical reactivity and more stable performance.In the four reduction processes with oxygen carriers prepared by all the four preparation methods,CO2 capture efficiencies exceed 88%; the yield rate of CO2 increases with the rate of carbon conversion,finally approaching 100%; and the combustion efficiencies are above 90%.These indicate that the oxygen carriers prepared by the four methods all have good performances for CO2 capture and high utilization degree of the combustible components.Freeze granulation and spray drying methods can be considered preferentially for batch preparation of oxygen carriers for the CLC of lignite.%采用冷冻成粒法、喷雾干燥法、浸渍法、机械混合法批量制备了Fe2O3/Al2O3氧载体,从氧载体产率、制备周期、物理化学表征、煤化学链燃烧中氧载体性能等角度比较各种批量制备方法,确定合适的批量制备技术.实验结果表明,冷冻成粒法的氧载体产率较高,机械性能最优;与褐煤的化学链燃烧实验中,喷雾干燥法和冷冻成粒法制备的氧载体导致碳转化速率较快,然后依次为浸渍法和机械混合法;且前两种方法制备的氧载体的循环稳定性

  4. What Is Carrier Screening? (United States)

    ... you want to learn. Search form Search Carrier screening You are here Home Testing & Services Testing for ... help you make the decision. What Is Carrier Screening? Carrier screening checks if a person is a " ...

  5. Using Low-Cost Iron-Based Materials as Oxygen Carriers for Chemical Looping Combustion Utilisation de matériaux bon marché à base de fer comme transporteur d’oxygène dans la combustion en boucle chimique

    Directory of Open Access Journals (Sweden)

    Jerndal E.


    Full Text Available In chemical looping combustion with solid fuels, the oxygen-carrier lifetime is expected to be shorter than with gaseous fuels. Therefore, it is particularly important to use low-cost oxygen carriers in solid fuel applications. Apart from being cheap, these oxygen carriers should be able to convert the CO and H2 produced from the solid fuel gasification and be sufficiently hard to withstand fragmentation. Several low-cost iron-based materials displayed high conversion of syngas and high mechanical strength and can be used for further development of the technology. These materials include oxide scales from Sandvik and Scana and an iron ore from LKAB. All tested oxygen carriers showed higher gas conversion than a reference sample, the mineral ilmenite. Generally, softer oxygen carriers were more porous and appeared to have a higher reactivity towards syngas. When compared with ilmenite, the conversion of CO was higher for all oxygen carriers and the conversion of H2 was higher when tested for longer reduction times. The oxygen carrier Sandvik 2 displayed the highest conversion of syngas and was therefore selected for solid fuel experiments. The conversion rate of solid fuels was higher with Sandvik 2 than with the reference sample, ilmenite. Pour appliquer la combustion en boucle chimique à des charges solides, il est important d’utiliser des matériaux transporteurs d’oxygène bon marché. En effet, la durée de vie du transporteur d’oxygène risque d’être plus courte sur charge solide que sur charge gazeuse. Ces matériaux doivent également bien convertir le monoxyde de carbone et l’hydrogène résultant de la gasification, tout en étant suffisamment durs pour résister à la fragmentation. Plusieurs matériaux ont montré un potentiel de conversion élevé sur le gaz de synthèse ainsi qu’une résistance mécanique élevée, ce qui permet d’envisager leur utilisation lors des développements futurs de la technologie. Parmi ces

  6. CaSO4溶液中表面处理对流动沸腾传热系数的影响%Effect of Surface Treatment on Flow Boiling Heat Transfer Coefficient in CaSO4 Containing Water

    Institute of Scientific and Technical Information of China (English)

    任晓光; 李铁凤; 赵起


    This paper reports the influence of heat transfer surface treatment on the formation of calcium sulphate deposit during flow boiling heat transfer. The surface of several test heaters was treated by surface modification techniques,such as dynamic mixing magnetron sputtering [DLC (diamond-like carbon), DLC-F (diamond-like carbon-fluorine) and AC (amorphous carbon)] and polishing to reduce surface energy. The results showed that heat transfer surface with low surface energy experienced significant reduction of formation of CaSO4 deposit. (1) Magnetron sputtering stainless steel heat transfer surface with DLC, DLC-F and plasma arc sputtering with AC did not change the surface roughness, but they reduced surface energy and improved heat transfer coefficient, so hindered CaSO4 deposit formation significantly. The DLC-F surface performed better than the DLC surface. (2) Surface energy played an important pole in improving heat transfer coefficient. The less the surface energy the more significant the heat transfer coefficient improved with other experimental conditions identical. (3) The polished surface improved the roughness of the heater, but owing to the high surface energy it was not better than the DLC-F surface for a long-term consideration on improving the heat transfer coefficient.

  7. Development of a technique for improving coefficient of variation of CaSO4:Dy teflon-based TLD personnel monitoring system in low-dose region

    International Nuclear Information System (INIS)

    In view of the importance of zero-dose background (null signal) in influencing the coefficient of variation in low-dose region, a technique for the estimation of the same from composite (gross) signal is developed for CaSO4:Dy-based personnel monitoring system being used in India. The technique is based on simple analysis of glow curves (GCs) of unexposed and exposed dosemeters, evolution of trend/model for the zero-dose curves, generation of simulation protocol for individual zero-dose curves, establishment of characteristics of GCs of exposed dosemeters and finally preparation of an algorithm to segregate the components from composite signal. The technique offers the separation of real-time background and gives superior results over other method of approximation of the background. The results also prove efficiency of the empirical trending and simulation protocol of background GCs. The proposed technique can be implemented in routine monitoring without any extra man hours and reader time. (authors)

  8. Studying dosimetric parameters of thermoluminescent dosemeter of CaSO4:Dy powder made in the Nuclear Research Institute for personal radiation dosimetry

    International Nuclear Information System (INIS)

    The research group of the Nuclear Research Institute (NRI) itself studied and successfully made thermoluminescent dosemeters (TLDs) using powder material of CaSO4:Dy in 2014. For external personal dosimetry, dosimetric parameters of the TLDs were surveyed by radiating with various gamma doses of 137Cs source and measured by Rexon-320 Reader such as glow curve with temperature, calibration factor (or response value), homogeneity of the batch, reproducibility of measurement, linearity of dose response, limit of detection, fading, light sensitivity, dose-rate dependence, and energy dependence of the response, etc. The studied results were shown that the dosemeters were ensured for personal dosimetry according to the standards of IEC-61066:2006. Besides, the TLDs were also radiated with standard doses of gamma (137Cs) and X-rays at the Secondary Standards Dosimetry Laboratory (SSDL) of the Institute for Nuclear Science and Technology in Hanoi. Comparison results on dose were shown that the TLDs have been confident. Therefore, they have been used for routinely external personal dosimetry for radiation workers in the NRI and other radiation installations from the beginning of 2015. (author)

  9. Gypsum (CaSO4·2H2O Scaling on Polybenzimidazole and Cellulose Acetate Hollow Fiber Membranes under Forward Osmosis

    Directory of Open Access Journals (Sweden)

    Tai-Shung Chung


    Full Text Available We have examined the gypsum (CaSO4·2H2O scaling phenomena on membranes with different physicochemical properties in forward osmosis (FO processes. Three hollow fiber membranes made of (1 cellulose acetate (CA, (2 polybenzimidazole (PBI/polyethersulfone (PES and (3 PBI-polyhedral oligomeric silsesquioxane (POSS/polyacrylonitrile (PAN were studied. For the first time in FO processes, we have found that surface ionic interactions dominate gypsum scaling on the membrane surface. A 70% flux reduction was observed on negatively charged CA and PBI membrane surfaces, due to strong attractive forces. The PBI membrane surface also showed a slightly positive charge at a low pH value of 3 and exhibited a 30% flux reduction. The atomic force microscopy (AFM force measurements confirmed a strong repulsive force between gypsum and PBI at a pH value of 3. The newly developed PBI-POSS/PAN membrane had ridge morphology and a contact angle of 51.42° ± 14.85° after the addition of hydrophilic POSS nanoparticles and 3 min thermal treatment at 95 °C. Minimal scaling and an only 1.3% flux reduction were observed at a pH value of 3. Such a ridge structure may reduce scaling by not providing a locally flat surface to the crystallite at a pH value of 3; thus, gypsum would be easily washed away from the surface.

  10. Development and evaluation of a new baDge/filter for thermoluminescent monitoring with CaSO4: Dy/PTFE

    International Nuclear Information System (INIS)

    Calcium Sulfate (CaSO4:Dy) phosphor Thermoluminescent Dosimeter (TLD) has been used by the Instituto de Pesquisas Energeticas e Nucleares (IPEN), SP, Brazil since 70's and 80's, due to important work of its researchers and collaborators. This phosphor advantages, beside the fact that it is produced by IPEN itself, begin to be more required and its disadvantages have became more apparent, in a global market more and more competitive. This phosphors was used primarily in environmental and area monitoring at IPEN facilities and in a few external institutions, once it presents more sensibility than other phosphors, like LiF:Mg. Its mainly disadvantage is a strong energetic dependence response to ionizing radiation, which must be corrected for its application in every radiation field. This phosphor has been used inside a badge which is an adaptation from photographic film badges used in the past. This badge permits a reasonable correction in the energetic dependence, only for orthogonal beam incidence. With the objective of improve the performance and reduce the energetic dependence on any incidence angle, reducing the dose measurement uncertainty too, this work presents a study on a new badge, with a new filter geometry, and its performance was compared to the actual dosimeter in use, with significant improve on results. Gamma irradiations of 60Co and x-rays of 25,1; 33; 37,3 and 82,1 keV, on incidence angles of 0 deg, 30 deg, 45 deg and 90 deg were done at facility conditions of IPEN. Semi-empirical computational simulation using finite differences in three dimensions were done. The results pointed out the best filter thickness and width for initiate the prototype production, in order to optimize the correction on energetic dependence on irradiation of photons of 33, 48, 118 and 1250 keV energies under many incidence angles. (author)

  11. Corrosion study on high power feeding of telecomunication copper cable in 5 wt.% CaSO4.2H2O solution (United States)

    Shamsudin, Shaiful Rizam; Hashim, Nabihah; Ibrahim, Mohd Saiful Bahri; Rahman, Muhammad Sayuzi Abdul; Idrus, Muhammad Amin; Hassan, Mohd Rezadzudin; Abdullah, Wan Razli Wan


    The studies were carried out to find out the best powering scheme over the copper telephone line. It was expected that the application of the higher power feeding could increase the data transfer and capable of providing the customer's satisfaction. To realize the application of higher remote power feeding, the potential of corrosion problem on Cu cables was studied. The natural corrosion behaviour of copper cable in the 0.5% CaSO4.2H2O solution was studied in term of open circuit potential for 30 days. The corrosion behaviour of higher power feeding was studied by the immersion and the planned interval test to determine the corrosion rate as well as the effect of voltage magnitudes and the current scheme i.e. positive direct (DC+) and alternating current (AC) at about 0.40 ± 0.01 mA/ cm2 current density. In the immersion test, both DC+ and AC scheme showed the increasing of feeding voltage magnitude has increased the corrosion rate of Cu samples starting from 60 to 100 volts. It was then reduced at about 100 - 120 volts which may due to the passive and transpassive mechanism. The corrosion rate was slowly reduced further from 120 to 200 volts. Visually, the positively charged of Cu cable was seems susceptible to severe corrosion, while AC scheme exhibited a slight corrosion reaction on the surface. However, the planned interval test and XRD results showed the corrosion activity of the copper cable in the studied solution was a relatively slow process and considered not to be corroded as a partially protective scale of copper oxide formed on the surface.

  12. The optically stimulated luminescence (OSL) properties of LiF:Mg,Ti, Li2B4O7:Cu, CaSO4:Tm, and CaF2:Mn thermoluminescent (TL) materials

    International Nuclear Information System (INIS)

    This paper reports on an investigation into the optically stimulated luminescence (OSL) properties of several known thermoluminescent materials, namely LiF:Mg,Ti, Li2B4O7:Cu, CaSO4:Tm, and CaF2:Mn. Samples were irradiated to air doses of 15 mGy, 150 mGy and 1.5 Gy and analyzed using a commercially available OSL reader system to determine their luminescence response to continuous blue and infrared light (IR) excitation, centered at 470 nm and 830 nm wavelengths, respectively. CaF2:Mn did not show an OSL response with either IR or blue light stimulation. Li2B4O7:Cu and LiF:Mg,Ti demonstrated relatively weak OSL signals only under blue light excitation. CaSO4:Tm exhibited OSL under both IR and blue light stimulation at sensitivities roughly one order of magnitude less than the OSL response of α-Al2O3:C under the same conditions. - Highlights: • Optically stimulated luminescence (OSL) properties of several known thermoluminescent materials were investigated. • CaF2:Mn did not show an OSL response with either IR or blue light stimulation. • Li2B4O7:Cu and LiF:Mg,Ti demonstrated very weak OSL signals only under blue light excitation. • CaSO4:Tm exhibited OSL under both IR and blue light stimulation. • OSL properties of CaSO4:Tm indicated an optimal OSL readout regime

  13. Study of LiF:Mg,Ti and CaSO4:Dy dosimeters TL response to electron beams of 6 MeV applied to radiotherapy using PMMA and solid water phantoms

    International Nuclear Information System (INIS)

    The performance of CaSO4:Dy and LiF:Mg,Ti dosimeters to electron beams applied to radiotherapy was investigated. The TL response of these dosimeters was studied for 6 MeV electron beams using PMMA and Solid Water (SW) phantoms. The dosimeters were previously separated in groups according to their TL individual sensitivities to 60Co gamma-radiation in air under electronic equilibrium conditions. After that, they were irradiated with 6 MeV electron doses of 0.1, 0.5, 1, 5 and 10 Gy using a linear accelerator Clinac 2100C Varian of Hospital Israelita Albert Einstein – HIAE. The electron beam irradiations were performed using a 10 × 10 cm2 field size, 100 cm source-phantom surface distance and the dosimeters were positioned at the depth of maximum dose (1.2 cm). The TL readings were carried out between 24 and 32 h after irradiation using a Harshaw 3500 TL reader. The TL dose–response of both type of dosimeters and phantoms presented linear behavior on the electron dose range from 0.1 to 5 Gy CaSO4:Dy dosimeter is 21 times more sensitive than LiF:Mg,Ti, dosimeter commonly used in clinical dosimetry. The obtained results indicate that the performance of CaSO4:Dy dosimeters is similar to LiF:Mg,Ti dosimeters and this material can be an alternative dosimetric material to be used to clinical electron beams dosimetry.

  14. Determination of self attenuation coefficient and relative TL efficiency of CaSO 4 :Dy, LiF:Mg,Cu,P and LiF:Mg,Ti TLDs - An alternate approach (United States)

    Bakshi, A. K.; Chatterjee, S.; Palani Selvam, T.; Joshi, V. J.; Chougaonkar, M. P.


    Self attenuation of TL and relative TL efficiency of polytetra fluoro ethylene (PTFE) embedded CaSO 4:Dy disc, LiF:Mg,Ti (MTS) disc and LiF:Mg,Cu,P (MCP-N) chip were determined in the present study for photons of energy 10-34 keV. The relative TL efficiency was determined using an alternative approach in which ratio of experimental response and corrected theoretical response was used instead of measuring the absolute TL emission in photon counting mode. For CaSO 4:Dy disc, it was found that with increasing the proportion of CaSO 4:Dy phosphor in the disc, the light attenuation coefficient increases. The light attenuation coefficient of MTS disc and MCP-N chip was found to be 23.4 and 45.5 cm -1, respectively. The relative TL efficiency in the photon energy range of 10-34 keV for MTS discs and MCP-N chips, evaluated in the present study matches well with the reported values in the literature.

  15. Oxygen Therapy (United States)

    Oxygen therapy is a treatment that provides you with extra oxygen. Oxygen is a gas that your body needs to function. Normally, your lungs absorb oxygen from the air you breathe. But some conditions ...

  16. Peptide-Carrier Conjugation

    DEFF Research Database (Denmark)

    Hansen, Paul Robert

    To produce antibodies against synthetic peptides it is necessary to couple them to a protein carrier. This chapter provides a nonspecialist overview of peptide-carrier conjugation. Furthermore, a protocol for coupling cysteine-containing peptides to bovine serum albumin is outlined.......To produce antibodies against synthetic peptides it is necessary to couple them to a protein carrier. This chapter provides a nonspecialist overview of peptide-carrier conjugation. Furthermore, a protocol for coupling cysteine-containing peptides to bovine serum albumin is outlined....

  17. Asymmetric Carrier Random PWM

    DEFF Research Database (Denmark)

    Mathe, Laszlo; Lungeanu, Florin; Rasmussen, Peter Omand;


    This paper presents a new fixed carrier frequency random PWM method, where a new type of carrier wave is proposed for modulation. Based on the measurements, it is shown that the spread effect of the discrete components from the motor current spectra is very effective independent of the modulation...

  18. Supplemental Oxygen (United States)

    ... Disease Lookup > COPD > Diagnosing and Treating COPD Supplemental Oxygen Sometimes with chronic obstructive pulmonary disease (COPD), lung ... in people with severe lung disease Three Ways Oxygen Therapy Is Supplied Compressed oxygen gas and liquid ...

  19. A design of a personal dosimeter based on a new TL material CaSO4:Dy,P for use in photon-beta radiation fields

    International Nuclear Information System (INIS)

    A personal dosimeter containing TL elements, KCT-300, based on a new TL material CaSO4:Dy,P was developed to be used in measurement of Hp(10) and Hp(0.07) in photon-beta radiation fields. The performance requirements provided by ANSI were adopted as a design criteria. The MCNPX Monte Carlo code was utilized to obtain design parameters affecting dosimeter response and successfully functioned as a desk-top design tool predicting dosimeter responses upon change of parameters. The fundamental response functions of the new TL dosimeter were acquired from experiments in the reference radiation field established in the Korea Atomic Energy Research Institute. The personal dosimeter designed in this study, KCT-300PB3, consists of three areas: the window area, the energy information area and the energy compensation area. The energy compensation area was designed to give a measurement of deep dose Hp(10) incurred by Photons with energy ranging from 54 to 662 keV. The shallow dose Hp(0.07) was calculated by applying an average shallow dose conversion factor of those photons to the deep dose determined. Consequently it was not necessary to resolve quality of photon beyond 54keV. To compensate for overkill of low energy photons by the front filter, a hole of 1.3 mm in diameter was placed on the front primary filter. By tapering entrance of hole at 60 .deg. angle, response of the energy compensation area for photons ranging from 54 to 662 keV with incidence angles below 60 .deg. met the isodirectional criteria specified in the ANSI N13.11 within ±6%. The energy information area was designed to focus on low energy X-rays below 54keV which wee easy to be identified. As a consequence, chances of wrong identification of photon energy in either X-rays or X-rays/137Cs gamma mixed field followed by large deviations in the evaluated doses were inherently reduced. The energy compensation area and the energy information area were designed to shield at least 96% of 90Sr/90Y beta particles for resolving beta-137Cs gamma mixed field. For photons beyond 35keV and beta radiation, TL outputs of the dosimeter elements at the energy compensation area and the window area directly relate to the deep dose and the shallow dose, respectively. This simplifies the dose evaluation algorithm. The results of performance test for the K CT-300PB3 after the ANSI N13.11 guidelines showed the values of performance indicator, B + S, were in the range of 0.026∼0.115 and met the prescribed performance limits. Compared to other types of contemporary TLD systems, it has been shown that performance of this dosimeter was to be improved. Of all design parameters, it was proved to be an effective way for response compensation to install rear filter of larger size than that of front filter. A rear filter of large size made the front filter thinner and simpler than in existing designs. Another finding is that the TL elements and the filters should be in contact as far as possible because any gap between them significantly alters the response. The approaches and techniques of personal dosimeter design used in this study can be generally applicable to design of any personal dosimeter incorporating some elements of a passive detector. To extend capacity of the Monte Carlo design tool, further study is recommended to resolve causes of the discrepancies between the measured and calculated responses of TL dosimeter for lower energy photons found in this study

  20. Using oxygen at home (United States)

    Oxygen - home use; COPD - home oxygen; Chronic obstructive airways disease - home oxygen; Chronic obstructive lung disease - home oxygen; Chronic bronchitis - home oxygen; Emphysema - home oxygen; Chronic respiratory ...

  1. Metabolic Response of Perfused Livers to Various Oxygenation Conditions


    Orman, Mehmet A.; Ierapetritou, Marianthi G.; Androulakis, Ioannis P.; Berthiaume, Francois


    Isolated liver perfusion systems have been used to characterize intrinsic metabolic changes in liver as a result of various perturbations, including systemic injury, hepatotoxin exposure, and warm ischemia. Most of these studies were done using hyperoxic conditions (95% O2) but without the use of oxygen carriers in the perfusate. Prior literature data do not clearly establish the impact of oxygenation, and in particular that of adding oxygen carriers to the perfusate, on the metabolic functio...

  2. Duchenne muscular dystrophy carriers

    International Nuclear Information System (INIS)

    By means of magnetic resonance imaging (MRI), the proton spin-lattice relaxation times (T1 values) of the skeletal muscles were measured in Duchenne muscular dystrophy (DMD) carriers and normal controls. The bound water fraction (BWF) was calculated from the T1 values obtained, according to the fast proton diffusion model. In the DMD carriers, T1 values of the gluteus maximus and quadriceps femoris muscles were significantly higher, and BWFs of these muscles were significantly lower than in normal control. Degenerative muscular changes accompanied by interstitial edema were presumed responsible for this abnormality. No correlation was observed between the muscle T1 and serum creatine kinase values. The present study showed that MRI could be a useful method for studying the dynamic state of water in both normal and pathological skeletal muscles. Its possible utility for DMD carrier detection was discussed briefly. (orig.)

  3. Oxygen analyzer (United States)

    Benner, William H.


    An oxygen analyzer which identifies and classifies microgram quantities of oxygen in ambient particulate matter and for quantitating organic oxygen in solvent extracts of ambient particulate matter. A sample is pyrolyzed in oxygen-free nitrogen gas (N.sub.2), and the resulting oxygen quantitatively converted to carbon monoxide (CO) by contact with hot granular carbon (C). Two analysis modes are made possible: (1) rapid determination of total pyrolyzable oxygen obtained by decomposing the sample at C., or (2) temperature-programmed oxygen thermal analysis obtained by heating the sample from room temperature to C. as a function of time. The analyzer basically comprises a pyrolysis tube containing a bed of granular carbon under N.sub.2, ovens used to heat the carbon and/or decompose the sample, and a non-dispersive infrared CO detector coupled to a mini-computer to quantitate oxygen in the decomposition products and control oven heating.

  4. Zaria Universal Oxygenator Holder Phase I


    Sunday Adoga Edaigbini; Ibrahim Zira Delia; Muhammad Balarabe Aminu


    Introduction: The conduct of cardiopulmonary bypass surgery requires the use of equipment and devices like the oxygenator. The oxygenator comes in different makes and each manufacturer customizes the carrier or ′holder′ of this device specific to their design. Aim: This paper presents an innovation designed to overcome the need to purchase a different holder for every oxygenator thereby cutting the cost. Materials and Methods: A sheet of iron measuring 1.9 cm (width) × 0.1 cm (thickness) was ...

  5. Oxygen Carriers for Chemical Looping Combustion - 4 000 h of Operational Experience Transporteurs d’oxygène pour la combustion en boucle chimique : expérience accumulée pendant 4 000 h d’opération

    Directory of Open Access Journals (Sweden)

    Lyngfelt A.


    Full Text Available Chemical Looping Combustion (CLC is a new combustion technology with inherent separation of the greenhouse gas CO2. The technology involves the use of a metal oxide as an oxygen carrier which transfers oxygen from combustion air to the fuel, and hence a direct contact between air and fuel is avoided. Two interconnected fluidized beds, a fuel reactor and an air reactor, are used in the process. The outlet gas from the fuel reactor consists of CO2 and H2O, and the latter is easily removed by condensation. Considerable research has been conducted on CLC in the last years with respect to oxygen carrier development, reactor design, system efficiencies and prototype testing. Today, more than 700 materials have been tested and the technology has been successfully demonstrated in chemical looping combustors in the size range 0.3-140 kW, using different types of oxygen carriers based on oxides of the metals Ni, Co, Fe, Cu and Mn. The total time of operational experience is more than 4 000 hours. From these tests, it can be established that almost complete conversion of the fuel can be obtained and 100% CO2 capture is possible. Most work so far has been focused on gaseous fuels, but the direct application to solid fuels is also being studied. This paper presents an overview of operational experience with oxygen carriers in chemical looping combustors. La combustion en boucle chimique (CLC est une nouvelle technique de combustion permettant la séparation intrinsèque du CO2. Dans ce procédé, un oxyde métallique est utilisé comme transporteur d’oxygène pour véhiculer l’oxygène de l’air vers le combustible, ce qui permet d’éviter un contact direct entre le combustible et l’air. Deux lits fluidisés interconnectés sont utilisés, le réacteur air et le réacteur de combustion. Les fumées du réacteur de combustion contiennent le CO2 et la vapeur d’eau qui peut être facilement éliminée par condensation. Des recherches consid

  6. Intestinal solute carriers

    DEFF Research Database (Denmark)

    Steffansen, Bente; Nielsen, Carsten Uhd; Brodin, Birger; Eriksson, André Huss; Andersen, Rikke; Frokjaer, Sven


    A large amount of absorptive intestinal membrane transporters play an important part in absorption and distribution of several nutrients, drugs and prodrugs. The present paper gives a general overview on intestinal solute carriers as well as on trends and strategies for targeting drugs and...

  7. Glycosylation of solute carriers

    DEFF Research Database (Denmark)

    Pedersen, Nis Borbye; Carlsson, Michael C; Pedersen, Stine Helene Falsig


    Solute carriers (SLCs) are one of the largest groups of multi-spanning membrane proteins in mammals and include ubiquitously expressed proteins as well as proteins with highly restricted tissue expression. A vast number of studies have addressed the function and organization of SLCs as well as...

  8. Information and Its Carriers. (United States)

    Herrmann, F.; And Others


    Describes: (1) the structure of a data transmission source, carrier, and receiver; (2) a quantitative measure for the amount of data, followed by some quantitative examples of data transmission processes; (3) the concept of data current; (4) data containers; and (5) how this information can be used to structure physics courses. (JN)

  9. Oxygen Delivering Biomaterials for Tissue Engineering (United States)

    Farris, Ashley L.; Rindone, Alexandra N.; Grayson, Warren L.


    Tissue engineering (TE) has provided promising strategies for regenerating tissue defects, but few TE approaches have been translated for clinical applications. One major barrier in TE is providing adequate oxygen supply to implanted tissue scaffolds, since oxygen diffusion from surrounding vasculature in vivo is limited to the periphery of the scaffolds. Moreover, oxygen is also an important signaling molecule for controlling stem cell differentiation within TE scaffolds. Various technologies have been developed to increase oxygen delivery in vivo and enhance the effectiveness of TE strategies. Such technologies include hyperbaric oxygen therapy, perfluorocarbon- and hemoglobin-based oxygen carriers, and oxygen-generating, peroxide-based materials. Here, we provide an overview of the underlying mechanisms and how these technologies have been utilized for in vivo TE applications. Emerging technologies and future prospects for oxygen delivery in TE are also discussed to evaluate the progress of this field towards clinical translation.

  10. Hungarian students’ carrier aspirations

    Directory of Open Access Journals (Sweden)

    A.S. Gubik


    Full Text Available The article analyzes the students’ carrier aspiration, right after their graduation and five years after their studies. It examines the differences arising from the students’ family business background and their most important social variables (gender, age. Then the study highlights the effects of study field on the students’ intention. The direct effect of education on starting an enterprise is undiscovered in the literature, the paper deals with the influence of availability and services use, offered by higher institutions.

  11. Comparison of human solute carriers


    Schlessinger, Avner; Matsson, Pär; Shima, James E.; Pieper, Ursula; Yee, Sook Wah; Kelly, Libusha; Apeltsin, Leonard; Stroud, Robert M.; Ferrin, Thomas E; Giacomini, Kathleen M.; Sali, Andrej


    Solute carriers are eukaryotic membrane proteins that control the uptake and efflux of solutes, including essential cellular compounds, environmental toxins, and therapeutic drugs. Solute carriers can share similar structural features despite weak sequence similarities. Identification of sequence relationships among solute carriers is needed to enhance our ability to model individual carriers and to elucidate the molecular mechanisms of their substrate specificity and transport. Here, we desc...

  12. Hydrogen monitoring in sodium loops using the carrier gas technique

    International Nuclear Information System (INIS)

    Analysis for hydrogen in liquid sodium is made by combination of membranes permeable to hydrogen and appropriate methods of hydrogen detection. Membranes are usually made of nickel. Hydrogen has been determined with a solid electrolyte cell consisting of a galvanic cell with zirconium oxide ceramic as the electrolyte and of an electrolytic oxygen dosage device with the same electrolyte. The oxygen stream has been controlled with the aid of the signal of the galvanic cell. Thus, a continuous coulometric control of hydrogen in the carrier gas stream has been achieved. A significant interfering factor in applying the carrier gas technique is the possible coverage of the nickel surface of the diffusion cell with oxide. High purity of the carrier gas is necessary for eliminating this effect, especially in the case of low hydrogen content of sodium. (author)

  13. Carrier transport uphill. I. General

    DEFF Research Database (Denmark)

    Rosenberg, T; Wilbrandt, W


    A quantitative treatment of a carrier pump operating with two carrier forms C and Z is presented. Asymmetric metabolic reactions are assumed to transform Z into C on one and C into Z on the other side of the membrane, establishing a carrier cycle. The kinetical consequences of this mechanism are...

  14. Maintainable substrate carrier for electroplating

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Chen-An; Abas, Emmanuel Chua; Divino, Edmundo Anida; Ermita, Jake Randal G.; Capulong, Jose Francisco S.; Castillo, Arnold Villamor; Ma, Diana Xiaobing


    One embodiment relates to a substrate carrier for use in electroplating a plurality of substrates. The carrier includes a non-conductive carrier body on which the substrates are placed and conductive lines embedded within the carrier body. A plurality of conductive clip attachment parts are attached in a permanent manner to the conductive lines embedded within the carrier body. A plurality of contact clips are attached in a removable manner to the clip attachment parts. The contact clips hold the substrates in place and conductively connecting the substrates with the conductive lines. Other embodiments, aspects and features are also disclosed.

  15. Appreciating Oxygen (United States)

    Weiss, Hilton M.


    Photosynthetic flora and microfauna utilize light from the sun to convert carbon dioxide and water into carbohydrates and oxygen. While these carbohydrates and their derivative hydrocarbons are generally considered to be fuels, it is the thermodynamically energetic oxygen molecule that traps, stores, and provides almost all of the energy that…

  16. Comparison of airline passenger oxygen systems. (United States)

    Byrne, N J


    The principal sources of oxygen for inflight passenger use, scheduled and unscheduled, are examined. Present practices of assessment of the passenger's "fitness to fly" are described. Three partner airlines, British Airways, U.S. Air, and Qantas, catering for more than 8000 oxygen requests annually, are compared. Analysis of customer use suggests that medical oxygen requests are frequently not clinically justified. The growth in demand, for both scheduled and unscheduled use of an expensive resource, supports the need for a "recommended best practice" among carriers. Passengers with respiratory disorders who will most benefit from inflight oxygen are vulnerable either to hypoxia or asthma. PMID:7487813

  17. Autonomous component carrier selection

    DEFF Research Database (Denmark)

    Garcia, Luis Guilherme Uzeda; Pedersen, Klaus; Mogensen, Preben


    in local areas, basing our study case on LTE-Advanced. We present extensive network simulation results to demonstrate that a simple and robust interference management scheme, called autonomous component carrier selection allows each cell to select the most attractive frequency configuration; improving...... management and efficient system operation. Due to the expected large number of user-deployed cells, centralized network planning becomes unpractical and new scalable alternatives must be sought. In this article, we propose a fully distributed and scalable solution to the interference management problem...

  18. Evaluation of different oxygen carriers for biomass tar reforming

    DEFF Research Database (Denmark)

    Mendiara, Teresa; Johansen, Joakim Myung; Utrilla, Rubén;


    /oxidizing cycles. Several variables affecting the reducing cycle were analyzed: temperature, time for the reduction step and H2O/C7H8 molar ratio. Ni40 and Mn40 presented interesting characteristics for CLR of biomass tar. Both showed stable reactivity to C7H8 after a few cycles. Ni40 showed a high tendency to...... carbon deposition compared to Mn40, specially at high temperatures. Carbon deposition could be controlled by decreasing the temperature and the time for the reduction step. The addition of water also reduced the amount of carbon deposited, which was completely avoided working with a H2O/C7H8 molar ratio...

  19. Materials for Chemical-Looping with Oxygen Uncoupling


    Tobias Mattisson


    Chemical-looping with oxygen uncoupling (CLOU) is a novel combustion technology with inherent separation of carbon dioxide. The process is a three-step process which utilizes a circulating oxygen carrier to transfer oxygen from the combustion air to the fuel. The process utilizes two interconnected fluidized bed reactors, an air reactor and a fuel reactor. In the fuel reactor, the metal oxide decomposes with the release of gas phase oxygen (step 1), which reacts directly with the fuel through...

  20. Particle temperature measurements in closed chamber detonations using thermoluminescence from Li2B4O7:Ag,Cu, MgB4O7:Dy,Li and CaSO4:Ce,Tb

    International Nuclear Information System (INIS)

    The present work describes the procedures and results from the first temperature measurements in closed chamber detonations obtained using the thermoluminescence (TL) of particles specifically developed for temperature sensing. Li2B4O7:Ag,Cu (LBO), MgB4O7:Dy,Li (MBO) and CaSO4:Ce,Tb (CSO) were tested separately in a total of 12 independent detonations using a closed detonation chamber at the Naval Surface Warfare Center, Indian Head Explosive Ordnance Disposal Technology Division (NSWC IHEODTD). Detonations were carried out using two different explosives: a high temperature plastic bonded explosive (HPBX) and a low temperature plastic bonded explosive (LPBX). The LPBX and HPBX charges produced temperatures experienced by the TL particles to be between ~550–670 K and ~700–780 K, respectively, depending on the shot. The measured temperatures were reproducible and typically higher than the thermocouple temperatures. These tests demonstrate the survivability of the TL materials and the ability to obtain temperature estimates in realistic conditions, indicating that TL may represent a reliable way of estimating the temperature experienced by free-flowing particles inside an opaque post-detonation fireball. - Highlights: • TL materials were tested in closed chamber detonations. • Temperatures experienced by the particles were ~550–670 K and ~700–780 K. • TL temperatures were reproducible and higher than thermocouple measurements. • Tests demonstrate TL material survival and ability to obtain temperature estimates


    Directory of Open Access Journals (Sweden)

    Daniel Posavec


    Full Text Available Modern liquefied natural gas carriers are double-bottom ships classified according to the type of LNG tank. The tanks are specially designed to store natural gas cooled to -161°C, the boiling point of methane. Since LNG is highly flammable, special care must be taken when designing and operating the ship. The development of LNG carriers has begun in the middle of the twentieth century. LNG carrier storage space has gradually grown to the current maximum of 260000 m3. There are more than 300 LNG carriers currently in operation (the paper is published in Croatian.

  2. Drug Carrier for Photodynamic Cancer Therapy

    Directory of Open Access Journals (Sweden)

    Tilahun Ayane Debele


    Full Text Available Photodynamic therapy (PDT is a non-invasive combinatorial therapeutic modality using light, photosensitizer (PS, and oxygen used for the treatment of cancer and other diseases. When PSs in cells are exposed to specific wavelengths of light, they are transformed from the singlet ground state (S0 to an excited singlet state (S1–Sn, followed by intersystem crossing to an excited triplet state (T1. The energy transferred from T1 to biological substrates and molecular oxygen, via type I and II reactions, generates reactive oxygen species, (1O2, H2O2, O2*, HO*, which causes cellular damage that leads to tumor cell death through necrosis or apoptosis. The solubility, selectivity, and targeting of photosensitizers are important factors that must be considered in PDT. Nano-formulating PSs with organic and inorganic nanoparticles poses as potential strategy to satisfy the requirements of an ideal PDT system. In this review, we summarize several organic and inorganic PS carriers that have been studied to enhance the efficacy of photodynamic therapy against cancer.

  3. Chemical Looping Pilot Plant Results Using a Nickel-Based Oxygen Carrier Résultats de l’expérimentation sur un pilote opérant en boucle chimique avec un matériau transporteur d’oxygène à base de nickel

    Directory of Open Access Journals (Sweden)

    Pröll T.


    Full Text Available A chemical looping pilot plant was designed, built and operated with a design fuel power of 120 kW (lower heating value, natural gas. The system consists of two Circulating Fluidized Bed (CFB reactors. Operating results are presented and evaluated for a highly reactive nickel-based oxygen carrier, total system inventory 65 kg. The performance in fuel conversion achieved is in the range of 99.8% (CH4 conversion and 92% (CO2 yield. In chemical looping reforming operation, it can be reported that thermodynamic equilibrium is reached in the fuel reactor and that all oxygen is absorbed in the air reactor as soon as the global stoichiometric air/fuel ratio is below 1 and the air reactor temperature is 900°C or more. Even though pure natural gas (98.6 vol.% CH4 without steam addition was fed to the fuel reactor, no carbon formation has been found as long as the global stoichiometric air/fuel ratio was larger than 0.4. Based on the experimental findings and on the general state of the art, it is concluded that niche applications such as industrial steam generation from natural gas or CO2-ready coupled production of H2 and N2 can be interesting pathways for immediate scale-up of the technology. Un pilote d’étude de la combustion en boucle chimique d’une puissance thermique de 120 kW a été dimensionné, construit et opéré. Il est constitué de deux lits circulants interconnectés. Les résultats d’opération qui sont présentés ont été obtenus avec un matériau transporteur d’oxygène très réactif à base de nickel. L’inventaire total du matériau est de 65 kg dans le pilote. La conversion du méthane atteinte est voisine de 99,8 % et le rendement en CO2 est de 92 %. Lorsqu’on opère en mode de reformage, l’équilibre thermodynamique est atteint dans le réacteur fioul. Tout l’oxygène est capté dans le réacteur air dès que le rapport stoechiométrique entre l’air et le méthane est inférieur à 1 et que la temp

  4. Thermodinamically stable phases in the CaO-SiO2-Al2O3-CaSO4-H2O closed system at 25 ºC. Application to cementitious systems

    Directory of Open Access Journals (Sweden)

    Blanco-Varela, M. T.


    Full Text Available One of the chief causes of cement and concrete deterioration is the loss of durability prompted by sulphate attack. The existing standards call for long test periods (2- 12 months. Thermodynamic modelling is a particularly appropriate technique for studying systems that only reach equilibrium in the long term. Used in the present study to establish the fields of thermodynamic stability for the phases in the CaO-SiO2-Al2O3-CaSO4-H2O system at 25 ºC. According to the model, gypsum is stable at sulphate ion concentrations of 1.23e-2 mol/kg and over, while ettringite exhibits stability at concentrations ranging from 7.64e-6 to 1.54e-2 mol/kg. Ettringite is compatible with all system phases except SH and gypsum only with ettringite, the C-S-H gels, AH3 and SH. None of the calcium aluminates or silicoaluminates in the system is compatible with gypsum: in its presence, they all decompose to cement deteriorating ettringite. Finally, the model revealed that the maximum sulphate concentration at which C-S-H gel is stable is slightly higher in systems with than without Al2O3.Uno de los principales problemas asociados al deterioro de cementos y hormigones es la pérdida de durabilidad por ataque de sulfatos. La normativa existente requiere largos tiempos de ensayo (2-12 meses. La modelización termodinámica es una técnica particularmente adecuada para el estudio de sistemas que alcanzan el equilibrio en tiempos largos. Aplicando esta metodología se han establecido los campos de estabilidad termodinámica de las fases del sistema CaO-SiO2-Al2O3-CaSO4-H2O a 25 ºC. El yeso es estable a partir de la [SO42-] = 1,23e-2 mol/kg, y la ettringita es estable en un rango de [SO42-] = 7,64e-6 -1,54e-2 mol/kg. La ettringita es compatible con todas las fases del sistema excepto con SH y el yeso sólo con la ettringita, los geles C-S-H, el AH3 y el SH. Ninguno de los aluminatos o silicoaluminatos cálcicos son compatibles con el yeso, en su presencia se descomponen dando etringita. Finalmente, la máxima [SO42-] en la que es estable el gel C-S-H es ligeramente superior en sistemas que contienen Al2O3 con respecto a los que no lo poseen.

  5. Carrier transport uphill. I. General

    DEFF Research Database (Denmark)

    Rosenberg, T; Wilbrandt, W


    A quantitative treatment of a carrier pump operating with two carrier forms C and Z is presented. Asymmetric metabolic reactions are assumed to transform Z into C on one and C into Z on the other side of the membrane, establishing a carrier cycle. The kinetical consequences of this mechanism are...... worked out with respect to net transport rate, initial rate, unidirectional fluxes including back-flow through the pump, maximum accumulation ratio, competitive inhibition and acceleration, counter transport, and metabolic poisoning. The energetics of the system are treated. The fact that the system...

  6. Basic Stand Alone Carrier Line Items PUF (United States)

    U.S. Department of Health & Human Services — This release contains the Basic Stand Alone (BSA) Carrier Line Items Public Use Files (PUF) with information from Medicare Carrier claims. The CMS BSA Carrier Line...

  7. A Novel Bio-carrier Fabricated Using 3D Printing Technique for Wastewater Treatment (United States)

    Dong, Yang; Fan, Shu-Qian; Shen, Yu; Yang, Ji-Xiang; Yan, Peng; Chen, You-Peng; Li, Jing; Guo, Jin-Song; Duan, Xuan-Ming; Fang, Fang; Liu, Shao-Yang


    The structure of bio-carriers is one of the key operational characteristics of a biofilm reactor. The goal of this study is to develop a series of novel fullerene-type bio-carriers using the three-dimensional printing (3DP) technique. 3DP can fabricate bio-carriers with more specialized structures compared with traditional fabrication processes. In this research, three types of fullerene-type bio-carriers were fabricated using the 3DP technique and then compared with bio-carrier K3 (from AnoxKaldnes) in the areas of physicochemical properties and biofilm growth. Images acquired by 3D profiling and SEM indicated that the surface roughness of the 3DP bio-carrier was greater than that of K3. Furthermore, contact angle data indicated that the 3DP bio-carriers were more hydrophilic than K3. The biofilm on the 3DP bio-carriers exhibited higher microbial activity and stronger adhesion ability. These findings were attributed to excellent mass transfer of the substrate (and oxygen) between the vapour-liquid-solid tri-phase system and to the surface characteristics. It is concluded that the novel 3DP fullerene-type bio-carriers are ideal carriers for biofilm adherence and growth.

  8. Motor carrier evaluation program plan

    International Nuclear Information System (INIS)

    The US Department of Energy (DOE) Transportation Management Program (TMP) has established a program to assist the DOE field offices and their contractors in evaluating the motor carriers used to transport DOE-owned hazardous and radioactive materials. This program was initiated to provide the DOE field offices with the tools necessary to help ensure, during this period of motor carrier deregulation, that only highly qualified carriers transport radioactive and hazardous commodities for the DOE. This program will assist DOE in maintaining their excellent performance record in the safe transportation of hazardous commodities. The program was also developed in response to public concern surrounding the transportation of hazardous materials. Representatives of other federal agencies, states, and tribal governments, as well as the news media, have expressed concern about the selection and qualification of carriers engaged in the transportation of Highway Route-Controlled Quantities (HRCQ) and Truckload (TL) quantities of radioactive material for the DOE. 8 refs

  9. Content Distribution for Telecom Carriers

    Directory of Open Access Journals (Sweden)

    Ben Falchuk


    Full Text Available Distribution of digital content is a key revenue opportunity for telecommunications carriers. As media content moves from analog and physical media-based distribution to digital on-line distribution, a great opportunity exists for carriers to claim their role in the media value chain and grow revenue by enhancing their broadband “all you can eat” high speed Internet access offer to incorporate delivery of a variety of paid content. By offering a distributed peer to peer content delivery capability with authentication, personalization and payment functions, carriers can gain a larger portion of the revenue paid for content both within and beyond their traditional service domains. This paper describes an approach to digital content distribution that leverages existing Intelligent Network infrastructure that many carriers already possess, as well as Web Services.

  10. Sustainable bioenergy carriers from wastes


    Pereira, M.A.; Cavaleiro, A. J.; Abreu, A. A.; Costa, J.C.; Sousa, D. Z.; Alves, M.M.


    The development of new technologies for renewable energy production is crucial for decreasing the reliance in fossil fuels and improving global sustainability. Waste materials are valuable resources that can be used for the production of energy carriers. Organic wastes can be anaerobically digested to ultimately produce methane. Hydrogen can be recovered from this process, if methanogenesis is inhibited. These energy carriers can also be derived from recalcitrant materials in a two step-proce...

  11. Comparison of LaFeO3, La0.8Sr0.2FeO3, and La0.8Sr0.2Fe0.9Co0.1O3 perovskite oxides as oxygen carrier for partial oxidation of methane

    Institute of Scientific and Technical Information of China (English)

    Xiaoping Dai; Changchun Yu; Qiong Wu


    Comparison of LaFeO3, La0.8Sr0.2FeO3, and La0.8Sr0.2Fe0.9Co0.1O3 perovskite oxides as oxygen cartier for partial oxidation of methane in the absence of gaseous oxygen was investigated by continuous flow reaction and sequential redox reaction. Methane was oxidized to syngas with high selectivity by oxygen species of perovskite oxides in the absence of gaseous oxygen. The sequential redox reaction revealed that the structural stability and continuous oxygen supply in redox re-action decreased over La0.8Sr0.2Fe0.9Co0.1O3 oxide, while LaFeO3 and Lao.sSro.2FeO3 exhibited excellent structural stability and continuous oxygen supply.

  12. Monitoring oxygenation. (United States)

    Severinghaus, John W


    Cyanosis was used for a century after dentists began pulling teeth under 100% N(2)O in 1844 because brief (2 min) severe hypoxia is harmless. Deaths came with curare and potent anesthetic respiratory arrest. Leland Clark's invention of a polarographic blood oxygen tension electrode (1954) was introduced for transcutaneous PO2 monitoring to adjust PEEP and CPAP PO2 to prevent premature infant blindness from excess O2 (1972). Oximetry for warning military aviators was tried after WW II but not used for routine monitoring until Takuo Aoyagi (1973) discovered an equation to measure SaO2 by the ratio of ratios of red and IR light transmitted through tissue as it changed with arterial pulses. Pulse oximetry (1982) depended on simultaneous technology improvements of light emitting red and IR diodes, tiny cheap solid state sensors and micro-chip computers. Continuous monitoring of airway anesthetic concentration and oxygen also became very common after 1980. Death from anesthesia fell 10 fold between 1985 and 2000 as pulse oximetry became universally used, but no proof of a causative relationship to pulse oximetry exists. It is now assumed that all anesthesiologist became much more aware of the dangers of prolonged hypoxia, perhaps by using the pulse oximeters. PMID:21717228

  13. Motor Carrier Evaluation Program procedure

    International Nuclear Information System (INIS)

    The US Department of Energy (DOE) Transportation Management Division (DOE-TMD) has the overall responsibility to provide a well-managed transportation program for the safe, efficient, and economical transportation of DOE-owned material. In the performance of these duties, the DOE-TMD has established an exemplary safety record in the transportation of hazardous materials. The DOE recognizes that its responsibility for hazardous material does not end when the shipments leave the DOE sites. A special partnership is needed between the DOE, the DOE contractors, and the carriers chosen to transport hazardous materials. As in any partnership, it is critical that DOE know essential information about its partner in this joint venture. In fulfillment of its responsibility for the safe transportation of radioactive materials as well as other hazardous commodities and wastes routinely shipped from many DOE locations nationwide, the DOE-TMD has developed this policy for a motor carrier evaluation program. It is the intent of the DOE-TMD that this Motor Carrier Evaluation Program be implemented at all DOE locations to the fullest extent practicable. This program will assist in the evaluation of carriers transporting Highway Route Controlled Quantities (HRCQ) of radioactive material, because these shipments frequently are in the ''public eye.'' The program will also evaluate truckload (TL) quantity transporters of hazardous materials, including radioactive material and chemical wastes. The program has also recently been expanded to include motor carriers transporting less-than-truckload (LTL) quantities of these materials

  14. Difficulty of carrier generation in orthorhombic PbO (United States)

    Liao, Min; Takemoto, Seiji; Xiao, Zewen; Toda, Yoshitake; Tada, Tomofumi; Ueda, Shigenori; Kamiya, Toshio; Hosono, Hideo


    Polycrystalline β-PbO films were grown by pulsed laser deposition in atmospheres ranging from oxygen-poor (the oxygen pressure of 0.01 Pa) to oxygen-rich (13 Pa) conditions, and the oxygen chemical potential was further enhanced by ozone annealing to examine hole doping. It was found that each of the as-grown β-PbO films showed poor electrical conductivity, σ attributed to the deep VBM of β-PbO. On the other hand, annealing β-PbO films in reactive oxygen-containing atmospheres (i.e., O3) led to a significantly enhanced electrical conductivity (i.e., σ > 7.1 × 102 S cm-1) but it is the result of the formation of an n-type PbO2 phase because oxygen chemical potential exceeded the phase boundary limit. The striking difference in carrier generation between PbO and SnO is discussed based on the electronic structures calculated by density functional theory.

  15. Carrier sense data highway system (United States)

    Frankel, Robert


    A data transmission system includes a transmission medium which has a certain propagation delay time over its length. A number of data stations are successively coupled to the transmission medium for communicating with one another. Each of the data stations includes a transmitter for originating signals, each signal beginning with a carrier of a duration which is at least the propagation delay time of the transmission medium. Each data station also includes a receiver which receives other signals from other data stations and inhibits operation of the transmitter at the same data station when a carrier of another signal is received.

  16. Injection deep level transient spectroscopy: An improved method for measuring capture rates of hot carriers in semiconductors

    International Nuclear Information System (INIS)

    An improved method for measuring the cross sections for carrier trapping at defects in semiconductors is described. This method, a variation of deep level transient spectroscopy (DLTS) used with bipolar transistors, is applied to hot carrier trapping at vacancy-oxygen, carbon-oxygen, and three charge states of divacancy centers (V2) in n- and p-type silicon. Unlike standard DLTS, we fill traps by injecting carriers into the depletion region of a bipolar transistor diode using a pulse of forward bias current applied to the adjacent diode. We show that this technique is capable of accurately measuring a wide range of capture cross sections at varying electric fields due to the control of the carrier density it provides. Because this technique can be applied to a variety of carrier energy distributions, it should be valuable in modeling the effect of radiation-induced generation-recombination currents in bipolar devices

  17. Injection deep level transient spectroscopy: An improved method for measuring capture rates of hot carriers in semiconductors (United States)

    Fleming, R. M.; Seager, C. H.; Lang, D. V.; Campbell, J. M.


    An improved method for measuring the cross sections for carrier trapping at defects in semiconductors is described. This method, a variation of deep level transient spectroscopy (DLTS) used with bipolar transistors, is applied to hot carrier trapping at vacancy-oxygen, carbon-oxygen, and three charge states of divacancy centers (V2) in n- and p-type silicon. Unlike standard DLTS, we fill traps by injecting carriers into the depletion region of a bipolar transistor diode using a pulse of forward bias current applied to the adjacent diode. We show that this technique is capable of accurately measuring a wide range of capture cross sections at varying electric fields due to the control of the carrier density it provides. Because this technique can be applied to a variety of carrier energy distributions, it should be valuable in modeling the effect of radiation-induced generation-recombination currents in bipolar devices.

  18. Injection deep level transient spectroscopy: An improved method for measuring capture rates of hot carriers in semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Fleming, R. M.; Seager, C. H.; Lang, D. V.; Campbell, J. M. [Sandia National Laboratories, Albuquerque, New Mexico 87185-1415 (United States)


    An improved method for measuring the cross sections for carrier trapping at defects in semiconductors is described. This method, a variation of deep level transient spectroscopy (DLTS) used with bipolar transistors, is applied to hot carrier trapping at vacancy-oxygen, carbon-oxygen, and three charge states of divacancy centers (V{sub 2}) in n- and p-type silicon. Unlike standard DLTS, we fill traps by injecting carriers into the depletion region of a bipolar transistor diode using a pulse of forward bias current applied to the adjacent diode. We show that this technique is capable of accurately measuring a wide range of capture cross sections at varying electric fields due to the control of the carrier density it provides. Because this technique can be applied to a variety of carrier energy distributions, it should be valuable in modeling the effect of radiation-induced generation-recombination currents in bipolar devices.

  19. 75 FR 72863 - Motor Carrier Safety Advisory Committee Public Meeting (United States)


    ... Federal Motor Carrier Safety Administration Motor Carrier Safety Advisory Committee Public Meeting AGENCY: Federal Motor Carrier Safety Administration, DOT. ACTION: Notice of Motor Carrier Safety Advisory Committee Meeting. SUMMARY: FMCSA announces that the Agency's Motor Carrier Safety Advisory Committee...

  20. 76 FR 12214 - Motor Carrier Safety Advisory Committee Public Meeting (United States)


    ... Federal Motor Carrier Safety Administration Motor Carrier Safety Advisory Committee Public Meeting AGENCY: Federal Motor Carrier Safety Administration, DOT. ACTION: Notice: Announcement of Motor Carrier Safety Advisory Committee meeting; request for comment. SUMMARY: The Federal Motor Carrier Safety...

  1. 75 FR 50797 - Motor Carrier Safety Advisory Committee Public Meeting (United States)


    ... Federal Motor Carrier Safety Administration Motor Carrier Safety Advisory Committee Public Meeting AGENCY: Federal Motor Carrier Safety Administration (FMCSA), DOT. ACTION: Notice of Motor Carrier Safety Advisory Committee Meeting. SUMMARY: FMCSA announces that its Motor Carrier Safety Advisory Committee (MCSAC)...

  2. Hot carrier degradation in semiconductor devices

    CERN Document Server


    This book provides readers with a variety of tools to address the challenges posed by hot carrier degradation, one of today’s most complicated reliability issues in semiconductor devices.  Coverage includes an explanation of carrier transport within devices and book-keeping of how they acquire energy (“become hot”), interaction of an ensemble of colder and hotter carriers with defect precursors, which eventually leads to the creation of a defect, and a description of how these defects interact with the device, degrading its performance. • Describes the intricacies of hot carrier degradation in modern semiconductor technologies; • Covers the entire hot carrier degradation phenomenon, including topics such as characterization, carrier transport, carrier-defect interaction, technological impact, circuit impact, etc.; • Enables detailed understanding of carrier transport, interaction of the carrier ensemble with the defect precursors, and an accurate assessment of how the newly created defects imp...

  3. Effect of Ash on Oxygen Carriers for the Application of Chemical Looping Combustion to a High Carbon Char Effet des cendres sur l’activité des porteurs d’oxygène dans la combustion du charbon en boucle chimique

    Directory of Open Access Journals (Sweden)

    Rubel A.


    Full Text Available The application of Chemical Looping Combustion (CLC to solid fuels is being investigated at the University of Kentucky, Center for Applied Energy Research (CAER with the aim of the development of a Pressurized Chemical Looping Combustion/Gasification (PCLC/G process for the generation of electricity from coal. One important aspect of the CLC of solid fuel is the understanding of the effect of ash on the reactivity of Oxygen Carriers (OCs. The effect of ash on the redox capabilities of two different iron oxide OCs and on their ability to oxidize coal char was studied. To determine the effect of ash on the reactivity and recycle of the OCs through multiple redox cycles, fly ash from a coal-fired power plant was used. These experiments were performed in a TGMS system using 500 mg of ash/OC mixtures containing different ash concentrations up to 75%. The reducing gas was composed of 10% H2, 15% CO, 20% CO2, and a balance of Ar and the oxidizing gas was 20% O2 in Ar. Oxidation/reductions were carried to near completion. The ash was found to contain OC activity related to inherent iron present in the ash confirmed by XRD. This resulted in increased weight gain/loss on oxidation/reduction. The rate of oxidation/reduction increased with ash concentration due to increased porosity of the OC/ash mixture and better access of the reactive gases to the OC target sites. The two OCs were then used to combust a beneficiated coal char in the TGMS with the only oxygen supplied by an iron oxide OC. The starting mixture was 10% char and 90% of one of two OCs studied. The spent material containing reduced OC and ash was re-oxidized and 10% more char was added for a second reduction of the OC and oxidation of the added char. This procedure was repeated for 5 cycles increasing the ash concentrations from 5 to 25% in the char/ash/OC mixture. Carbon removal was 92 to 97.8 and 97.3 to 99.7% for the two different iron oxide OCs tested. Ash was not detrimental to the

  4. Effect of oxygen on the response of a constant-current 63Ni electron-capture detector

    International Nuclear Information System (INIS)

    A constant-current electron-capture detector (ECD) with a 63Ni ionization cell has been used in a study of the effect of oxygen in nitrogen carrier gas on its response to several compounds. Because of the greatly increased linear dynamic range and the high temperature capabilities of this instrument, oxygen contamination of the carrier gas was found to be much less harmful to the chromatogram baseline than had been previously reported for earlier ECD models. Measurements of the changes in the molar responses of several compounds caused by the addition of up to 2000 ppm of oxygen to the nitrogen carrier gas have been made. For the chlorinated hydrocarbons studied, an effect of oxygen on their molar responses was observed only with the highest oxygen dopings. Anthracene behaved differently, showing an increased molar response at very low levels of oxygen doping. These results suggest that constant-current ECD analyses of polynuclear aromatics may be very sensitive to uncontrolled oxygen contamination of carrier gas, while those of halocarbons will not. For 1-chlorobutane a greatly enhanced response factor is caused by doping of the carrier gas with large amounts of oxygen. As this effect is observed at high detector temperatures where the baseline frequency is only moderately impared by oxygen, oxygen doping is suggested as a means of improving the ECD sensitivity to molecules that have only one or a few halogen atoms. Two reaction mechanisms are proposed to account for the oxygen effects observed. (Auth.)

  5. Carrier Deformability in Drug Delivery. (United States)

    Morilla, Maria Jose; Romero, Eder Lilia


    Deformability is a key property of drug carriers used to increase the mass penetration across the skin without disrupting the lipid barrier. Highly deformable vesicles proved to be more effective than conventional liposomes in delivering drugs into and across the mammalian skin upon topical non occlusive application. In the past five years, highly deformable vesicles have been used for local delivery of drugs on joint diseases, skin cancer, atopic dermatitis, would healing, psoriasis, scar treatment, fungal, bacteria and protozoa infections. Promising topical vaccination strategies rely also in this type of carriers. Here we provide an overview on the main structural and mechanical features of deformable vesicles, to finish with an extensive update on their latest preclinical applications. PMID:26675226

  6. Fatigue reliability for LNG carrier

    Institute of Scientific and Technical Information of China (English)

    Xiao Taoyun; Zhang Qin; Jin Wulei; Xu Shuai


    The procedure of reliability-based fatigue analysis of liquefied natural gas (LNG) carrier of membrane type under wave loads is presented. The stress responses of the hotspots in regular waves with different wave heading angles and wave lengths are evaluated by global ship finite element method (FEM). Based on the probabilistic distribution function of hotspots' short-term stress-range using spectral-based analysis, Weibull distribution is adopted and discussed for fitting the long-term probabilistic distribution of stress-range. Based on linear cumulative damage theory, fatigue damage is characterized by an S-N relationship, and limit state function is established. Structural fatigue damage behavior of several typical hotspots of LNG middle ship section is clarified and reliability analysis is performed. It is believed that the presented results and conclusions can be of use in calibration for practical design and initial fatigue safety evaluation for membrane type LNG carrier.

  7. Engineering the oxygen sensing regulation results in an enhanced recombinant human hemoglobin production by Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Martínez, José L.; Liu, Lifang; Petranovic, Dina;


    Efficient production of appropriate oxygen carriers for transfusions (blood substitutes or artificial blood) has been pursued for many decades, and to date several strategies have been used, from synthetic polymers to cell-free hemoglobin carriers. The recent advances in the field of metabolic en...

  8. Home Oxygen Therapy (United States)

    ... Oxygen Therapy Font: Aerosol Delivery Oxygen Resources Immunizations Pollution Nutrition Exercise Coming Of Age Older Adults Allergy ... oxygen is so cold it can hurt your skin. Keep a fire extinguisher close by, and let ...

  9. Gemini surfactants as gene carriers

    Directory of Open Access Journals (Sweden)

    Teresa Piskorska


    Full Text Available Gemini surfactants are a new class of amphiphilic compounds built from two classic surfactant moieties bound together by a special spacer group. These compounds appear to be excellent for creating complexes with DNA and are effective in mediating transfection. Thanks to their construction, DNA carrier molecules built from gemini surfactants are able to deliver genes to cells of almost any DNA molecule size, unattainable when using viral gene delivery systems. Moreover, they are much safer for living organisms.

  10. Recursive SDN for Carrier Networks


    McCauley, James; Liu, Zhi; Panda, Aurojit; Koponen, Teemu; Raghavan, Barath; Rexford, Jennifer; Shenker, Scott


    Control planes for global carrier networks should be programmable (so that new functionality can be easily introduced) and scalable (so they can handle the numerical scale and geographic scope of these networks). Neither traditional control planes nor new SDN-based control planes meet both of these goals. In this paper, we propose a framework for recursive routing computations that combines the best of SDN (programmability) and traditional networks (scalability through hierarchy) to achieve t...

  11. Biocheese: A Food Probiotic Carrier


    J. M. Castro; M. E. Tornadijo; Fresno, J. M.; H. Sandoval


    This review describes some aspects related to the technological barriers encountered in the development and stability of probiotic cheeses. Aspects concerning the viability of probiotic cultures in this matrix are discussed and the potential of cheese as a biofunctional food carrier is analyzed, outlying some points related to health and safety. In general, the manufacture of probiotic cheese should have little change when compared with the elaboration of cheese in the traditional way. The ph...

  12. Preventative maintenance of straddle carriers

    Directory of Open Access Journals (Sweden)

    Si Li


    Full Text Available Background: Robotic vehicles such as straddle carriers represent a popular form of cargo handling amongst container terminal operators.Objectives: The purpose of this industry-driven study is to model preventative maintenance (PM influences on the operational effectiveness of straddle carriers.Method: The study employs historical data consisting of 21 273 work orders covering a 27-month period. Two models are developed, both of which forecast influences of PM regimes for different types of carrier.Results: The findings of the study suggest that the reliability of the straddle fleet decreases with increased intervals of PM services. The study also finds that three factors – namely resources, number of new straddles, and the number of new lifting work centres – influence the performances of straddles.Conclusion: The authors argue that this collaborative research exercise makes a significant contribution to existing supply chain management literature, particularly in the area of operations efficiency. The study also serves as an avenue to enhance relevant management practice.

  13. Responsible implementation of expanded carrier screening. (United States)

    Henneman, Lidewij; Borry, Pascal; Chokoshvili, Davit; Cornel, Martina C; van El, Carla G; Forzano, Francesca; Hall, Alison; Howard, Heidi C; Janssens, Sandra; Kayserili, Hülya; Lakeman, Phillis; Lucassen, Anneke; Metcalfe, Sylvia A; Vidmar, Lovro; de Wert, Guido; Dondorp, Wybo J; Peterlin, Borut


    This document of the European Society of Human Genetics contains recommendations regarding responsible implementation of expanded carrier screening. Carrier screening is defined here as the detection of carrier status of recessive diseases in couples or persons who do not have an a priori increased risk of being a carrier based on their or their partners' personal or family history. Expanded carrier screening offers carrier screening for multiple autosomal and X-linked recessive disorders, facilitated by new genetic testing technologies, and allows testing of individuals regardless of ancestry or geographic origin. Carrier screening aims to identify couples who have an increased risk of having an affected child in order to facilitate informed reproductive decision making. In previous decades, carrier screening was typically performed for one or few relatively common recessive disorders associated with significant morbidity, reduced life-expectancy and often because of a considerable higher carrier frequency in a specific population for certain diseases. New genetic testing technologies enable the expansion of screening to multiple conditions, genes or sequence variants. Expanded carrier screening panels that have been introduced to date have been advertised and offered to health care professionals and the public on a commercial basis. This document discusses the challenges that expanded carrier screening might pose in the context of the lessons learnt from decades of population-based carrier screening and in the context of existing screening criteria. It aims to contribute to the public and professional discussion and to arrive at better clinical and laboratory practice guidelines. PMID:26980105

  14. Nanoporous nanocrystalline monoclinic zirconia for luminescent oxygen sensors (United States)

    Fidelus, Janusz D.; Zhou, Wuzong; Tenderenda, Tadeusz; Nasiłowski, Tomasz


    In this work we present a nanocrystalline monoclinic ZrO2 with large free volumen open towards the nanocrystals surface dedicated for optical oxygen sensors. Nanoporous zirconia nanopowder was fabricated in hydrothermal microwave-driven process followed by annealing at 800°C. Metal-coated optical fibers are proposed as a light carrier when the working temperature exceeds 500°C. The obtained results may also find application in luminescent fiber optic oxygen sensors.

  15. 49 CFR 376.22 - Exemption for private carrier leasing and leasing between authorized carriers. (United States)


    ... 49 Transportation 5 2010-10-01 2010-10-01 false Exemption for private carrier leasing and leasing... MOTOR CARRIER SAFETY REGULATIONS LEASE AND INTERCHANGE OF VEHICLES Exemptions for the Leasing Regulations § 376.22 Exemption for private carrier leasing and leasing between authorized carriers....

  16. Investigating thermal donors in n-type Cz silicon with carrier density imaging

    Directory of Open Access Journals (Sweden)

    Yu Hu


    Full Text Available A new method to map the thermal donor concentration in silicon wafers using carrier density imaging is presented. A map of the thermal donor concentration is extracted with high resolution from free carrier density images of a silicon wafer before and after growth of thermal donors. For comparison, free carrier density mapping is also performed using the resistivity method together with linear interpolation. Both methods reveal the same distribution of thermal donors indicating that the carrier density imaging technique can be used to map thermal donor concentration. The interstitial oxygen concentration can also be extracted using the new method in combination with Wijaranakula's model. As part of this work, the lifetime at medium injection level is correlated to the concentration of thermal donors in the as-grown silicon wafer. The recombination rate is found to depend strongly on the thermal donor concentration except in the P-band region.

  17. Low-cost carriers fare competition effect


    Carmona Benitez, R.B.; Lodewijks, G.


    This paper examines the effects that low-cost carriers (LCC’s) produce when entering new routes operated only by full-service carriers (FSC’s) and routes operated by low-cost carriers in competition with full-service carriers. A mathematical model has been developed to determine what routes should be operated by a low-cost carrier with better possibilities to subsist. The proposed model in this paper was set up by analyzing The United States domestic air transport market 2005 year database fr...

  18. Impact of carriers in oral absorption

    DEFF Research Database (Denmark)

    Gram, Luise Kvisgaard; Rist, Gerda Marie; Lennernäs, Hans; Steffansen, Bente

    Carriers may mediate the permeation across enterocytes for drug substances being organic anions. Carrier mediated permeation for the organic anions estrone-3-sulfate (ES) and glipizide across Caco-2 cells were investigated kinetically, and interactions on involved carriers evaluated. Initial...... with K(m) 44microM and 38microM, respectively. BCRP inhibition affected both absorptive an exsorptive P(EPA) and P(APP) for ES. Glipizide apical P(UP) and absorptive P(APP) were not inhibitable. Basolateral P(UP) for glipizide was inhibitable, its P(EPA) prevented, and P(UP) was saturable with K(m) 56......microM, but exsorptive P(APP) was not affected. Carrier mediated exsorption kinetics for ES are seen at both apical and basolateral membranes, resulting in predominant exsorption despite presence of absorptive carrier(s). Carrier mediated basolateral P(UP) for glipizide was observed, but glipizide P...

  19. Selection and evaluation of biofilm carrier in anaerobic digestion treatment of cattle manure

    International Nuclear Information System (INIS)

    Selection and evaluation of biofilm carrier represent the two significant ways for improving the anaerobic digesters. This study investigated the performances of the AD (anaerobic digestion) reactors using three types of fibrous biofilm carriers, including the ACF (activated carbon fiber), the PVAF (polyvinyl alcohol fiber) and the GF (glass fiber). The biogas and methane production, pH, COD (chemical oxygen demand), TS (total solids), VS (volatile solids), residual coenzyme F420 as well as the residual amount of methanogen were measured periodically during the experimental run. Also, the SEM (scanning electron microscopy) was used to identify the microbial consortium and their attachments onto the surface of ACF carrier. The ACF carrier performed better than the other two types of carriers in achieving higher amount of biogas and methane production and pollutants' removal. The experimental results also demonstrated that the ACF carrier could make the reactor keep higher biogas and methane productions than the control blank reactor during the long run. -- Highlights: → ACF as biofilm carrier is superior to PVAF and GF in AD treatment of cattle manure. → ACF makes the reactor keep higher biogas and methane productions. → ACF enhances microorganism's immobilization.

  20. Artificial oxygen transport protein

    Energy Technology Data Exchange (ETDEWEB)

    Dutton, P. Leslie


    This invention provides heme-containing peptides capable of binding molecular oxygen at room temperature. These compounds may be useful in the absorption of molecular oxygen from molecular oxygen-containing atmospheres. Also included in the invention are methods for treating an oxygen transport deficiency in a mammal.

  1. Neural nets and chaotic carriers

    CERN Document Server

    Whittle, Peter


    ""Neural Nets and Chaotic Carriers"" develops rational principles for the design of associative memories, with a view to applying these principles to models with irregularly oscillatory operation so evident in biological neural systems, and necessitated by the meaninglessness of absolute signal levels. Design is based on the criterion that an associative memory must be able to cope with 'fading data', i.e., to form an inference from the data even as its memory of that data degrades. The resultant net shows striking biological parallels. When these principles are combined with the Freeman speci

  2. Carrier frequencies, holomorphy and unwinding

    CERN Document Server

    Coifman, Ronald R; Wu, Hau-tieng


    We prove that functions of intrinsic-mode type (a classical models for signals) behave essentially like holomorphic functions: adding a pure carrier frequency $e^{int}$ ensures that the anti-holomorphic part is much smaller than the holomorphic part $ \\| P_{-}(f)\\|_{L^2} \\ll \\|P_{+}(f)\\|_{L^2}.$ This enables us to use techniques from complex analysis, in particular the \\textit{unwinding series}. We study its stability and convergence properties and show that the unwinding series can stabilize and show that the unwinding series can provide a high resolution time-frequency representation, which is robust to noise.

  3. Technetium diagnostic agent and carrier

    International Nuclear Information System (INIS)

    A stable sup(99m)Tc-labelled radioactive diagnostic agent is produced by contacting sup(99m)Tc-containing pertechnetate with a non-radioactive carrier comprising a chelating agent, a water-soluble reducing agent and a stabilizer. The stabilizer is chosen from ascorbic acid and erythorbic acid and their pharmaceutically acceptable salts and esters. A mole ratio of more than 100 moles ascorbic or erythorbic acid to 1 mole of reducing agent provides a stable composition at high levels of radioactivity

  4. Wuestite - a solar energy carrier

    Energy Technology Data Exchange (ETDEWEB)

    Weidenkaff, A.; Nueesch, P.; Wokaun, A. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Reller, A. [Hamburg Univ., Hamburg (Germany)


    Hydrogen is produced when Wuestite (Fe{sub 1-y}O) is oxidised by water. This reaction is part of a two-step thermochemical metal oxide cycle for the storage of solar energy in the form of chemical energy carriers, characterised by a high chemical potential. The reaction was studied in a tubular furnace with on-line gas analysis and further characterised in detail by DTA und high-temperature X-ray powder diffraction. The influence of non-stoichiometry, morphology and temperature on the mechanism and kinetics of the water-splitting reaction was determined. (author) 3 figs., tabs., 3 refs.

  5. 78 FR 66801 - Motor Carrier Safety Advisory Committee; Charter Renewal (United States)


    ... Federal Motor Carrier Safety Administration Motor Carrier Safety Advisory Committee; Charter Renewal AGENCY: Federal Motor Carrier Safety Administration (FMCSA), DOT. ACTION: Announcement of advisory... Committee that provides the Agency with advice and recommendations on motor carrier safety programs...

  6. Dynamic Charge Carrier Trapping in Quantum Dot Field Effect Transistors. (United States)

    Zhang, Yingjie; Chen, Qian; Alivisatos, A Paul; Salmeron, Miquel


    Noncrystalline semiconductor materials often exhibit hysteresis in charge transport measurements whose mechanism is largely unknown. Here we study the dynamics of charge injection and transport in PbS quantum dot (QD) monolayers in a field effect transistor (FET). Using Kelvin probe force microscopy, we measured the temporal response of the QDs as the channel material in a FET following step function changes of gate bias. The measurements reveal an exponential decay of mobile carrier density with time constants of 3-5 s for holes and ∼10 s for electrons. An Ohmic behavior, with uniform carrier density, was observed along the channel during the injection and transport processes. These slow, uniform carrier trapping processes are reversible, with time constants that depend critically on the gas environment. We propose that the underlying mechanism is some reversible electrochemical process involving dissociation and diffusion of water and/or oxygen related species. These trapping processes are dynamically activated by the injected charges, in contrast with static electronic traps whose presence is independent of the charge state. Understanding and controlling these processes is important for improving the performance of electronic, optoelectronic, and memory devices based on disordered semiconductors. PMID:26099508

  7. Oxygen-enhanced combustion

    CERN Document Server

    Baukal, Charles E


    Combustion technology has traditionally been dominated by air/fuel combustion. However, two developments have increased the significance of oxygen-enhanced combustion-new technologies that produce oxygen less expensively and the increased importance of environmental regulations. Advantages of oxygen-enhanced combustion include less pollutant emissions as well as increased energy efficiency and productivity. Oxygen-Enhanced Combustion, Second Edition compiles information about using oxygen to enhance industrial heating and melting processes. It integrates fundamental principles, applications, a

  8. Improvement of Thermoelectric Properties of a-InGaZnO Thin Film by Optimizing Carrier Concentration (United States)

    Fujimoto, Yuta; Uenuma, Mutsunori; Ishikawa, Yasuaki; Uraoka, Yukiharu


    We have investigated the thermoelectric properties of amorphous InGaZnO (a-IGZO) thin films optimized by adjusting the carrier concentration. The a-IGZO films were produced under various oxygen flow ratios [O2/(Ar + O2)] using radiofrequency magnetron sputtering. The Seebeck coefficient and electrical conductivity were measured from 100 K to 400 K. The measured Seebeck coefficient and electrical conductivity show a trade-off relation. The carrier concentration in the a-IGZO films increased with decreasing oxygen flow ratio. This result can be adequately explained by the increment of oxygen vacancies. We found that the power factor (PF) at 300 K had a maximum value of 82 × 10-6 W/m-K2, where the carrier density was 7.7 × 1019 cm-3. These results indicate that a-IGZO shows maximal PF in the transition region from nondegenerate to degenerate state.

  9. Evidence of low-mobile charge carriers in YBa2Cu3O6+x

    International Nuclear Information System (INIS)

    The present work results reveal that the heterogeneous system is one of the forms of oxygen nonstoichiometry, realization of oxygen-deficient YBa2Cu3O6+x. It is noteworthy that NMP is formed above 980 C through labile oxygen redistribution and leaves the lattice of heavy ions invariable. Being a random microscopically inhomogeneous media the NW exhibits a number of anomalous dielectric properties absent for each separate component. Probably the degree of labile oxygen segregation in NMP is so high, that static permittivity of dielectric phase is completely determined by small polarons. On the other hand the NMP DF measurements provide an effective values of mobility and its activation energy giving a rough idea of small polarons dynamics. At low temperature the picture is complicated by nonequilibrium charge carriers excitation. To elaborate an adequate model of the entire phenomenon, more detailed information on oxygen positions and phase percolation threshold is necessary

  10. Carrier detection in xeroderma pigmentosum

    International Nuclear Information System (INIS)

    We were able to detect clinically normal carriers of xeroderma pigmentosum (XP) genes with coded samples of either peripheral blood lymphocytes or skin fibroblasts, using a cytogenetic assay shown previously to detect individuals with cancer-prone genetic disorders. Metaphase cells of phytohemagglutinin-stimulated T-lymphocytes from eight individuals who are obligate heterozygotes for XP were compared with those from nine normal controls at 1.3, 2.3, and 3.3 h after x-irradiation (58 R) during the G2 phase of the cell cycle. Lymphocytes from the XP heterozygotes had twofold higher frequencies of chromatid breaks or chromatid gaps than normal (P less than 10(-5)) when fixed at 2.3 or 3.3 h after irradiation. Lymphocytes from six XP homozygotes had frequencies of breaks and gaps threefold higher than normal. Skin fibroblasts from an additional obligate XP heterozygote, when fixed approximately 2 h after x-irradiation (68 R), had a twofold higher frequency of chromatid breaks and a fourfold higher frequency of gaps than fibroblasts from a normal control. This frequency of aberrations in cells from the XP heterozygote was approximately half that observed in the XP homozygote. The elevated frequencies of chromatid breaks and gaps after G2 phase x-irradiation may provide the basis of a test for identifying carriers of the XP gene(s) within known XP families