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Sample records for oxide svo agvsub

  1. SvO(2)-guided resuscitation for experimental septic shock: effects of fluid infusion and dobutamine on hemodynamics, inflammatory response, and cardiovascular oxidative stress.

    Science.gov (United States)

    Rosário, André Loureiro; Park, Marcelo; Brunialti, Milena Karina; Mendes, Marialice; Rapozo, Marjorie; Fernandes, Denise; Salomão, Reinaldo; Laurindo, Francisco Rafael; Schettino, Guilherme Paula; Azevedo, Luciano Cesar P

    2011-12-01

    The pathogenetic mechanisms associated to the beneficial effects of mixed venous oxygen saturation (SvO(2))-guided resuscitation during sepsis are unclear. Our purpose was to evaluate the effects of an algorithm of SvO(2)-driven resuscitation including fluids, norepinephrine and dobutamine on hemodynamics, inflammatory response, and cardiovascular oxidative stress during a clinically resembling experimental model of septic shock. Eighteen anesthetized and catheterized pigs (35-45 kg) were submitted to peritonitis by fecal inoculation (0.75 g/kg). After hypotension, antibiotics were administered, and the animals were randomized to two groups: control (n = 9), with hemodynamic support aiming central venous pressure 8 to 12 mmHg, urinary output 0.5 mL/kg per hour, and mean arterial pressure greater than 65 mmHg; and SvO(2) (n = 9), with the goals above, plus SvO(2) greater than 65%. The interventions lasted 12 h, and lactated Ringer's and norepinephrine (both groups) and dobutamine (SvO(2) group) were administered. Inflammatory response was evaluated by plasma concentration of cytokines, neutrophil CD14 expression, oxidant generation, and apoptosis. Oxidative stress was evaluated by plasma and myocardial nitrate concentrations, myocardial and vascular NADP(H) oxidase activity, myocardial glutathione content, and nitrotyrosine expression. Mixed venous oxygen saturation-driven resuscitation was associated with improved systolic index, oxygen delivery, and diuresis. Sepsis induced in both groups a significant increase on IL-6 concentrations and plasma nitrate concentrations and a persistent decrease in neutrophil CD14 expression. Apoptosis rate and neutrophil oxidant generation were not different between groups. Treatment strategies did not significantly modify oxidative stress parameters. Thus, an approach aiming SvO(2) during sepsis improves hemodynamics, without any significant effect on inflammatory response and oxidative stress. The beneficial effects associated

  2. The Change from SOV to SVO in Ancient Greek.

    Science.gov (United States)

    Taylor, Ann

    1994-01-01

    Examines the distribution of clause types in ancient Greek during the Homeric (pre-800 B.C.) and Hellenistic (ca. 100 A.D.) periods, as well as an intermediate period (ca. 450 B.C.), delineating the evolution from a subject-object-verb (SOV) to a subject-verb-object (SVO) structure. (49 references) (MDM)

  3. Lithium diffusion in silver vanadium oxide

    International Nuclear Information System (INIS)

    Takeuchi, E.S.; Thiebolt, W.C. III

    1989-01-01

    Lithium/silver vanadium oxide (SVO) batteries have been developed to power implantable devices. The voltage of Li/SVO cells decreases with discharge allowing state of charge assessment by accurate determination of the cells' open circuit voltage. The open circuit voltage recovery of Li/SVO cells was monitored during intermittent high rate discharge. It was found that the voltage does not recover at the same rate or magnitude at all depths of discharge. The authors describe lithium diffusion in SVO studied by low scan rate voltammetry where utilization of SVO at various scan rates was used to determine the diffusion rate of lithium. A pulse technique was also used where the rate of lithium diffusion was measured at various depths of discharge

  4. Electrochemical intercalation of lithium into polypyrrole/silver vanadium oxide composite used for lithium primary batteries

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jong-Won; Popov, Branko N. [Center for Electrochemical Engineering, Department of Chemical Engineering, University of South Carolina, Columbia, SC 29208 (United States)

    2006-10-20

    Hybrid composites of polypyrrole (PPy) and silver vanadium oxide (SVO) used for lithium primary batteries were chemically synthesized by an oxidative polymerization of pyrrole monomer on the SVO surface in an acidic medium. The composite electrode exhibited higher discharge capacity and better rate capability as compared with the pristine SVO electrode. The improvement in electrochemical performance of the composite electrode was due to PPy which accommodates lithium ions and also enhances the SVO utilization. Chronoamperometric and ac-impedance measurements indicated that lithium intercalation proceeds under the mixed control by interfacial charge transfer and diffusion. The enhanced SVO utilization in the composite electrode results from a facilitated kinetics of interfacial charge transfer in the presence of PPy. (author)

  5. Electrochemical intercalation of lithium into polypyrrole/silver vanadium oxide composite used for lithium primary batteries

    Science.gov (United States)

    Lee, Jong-Won; Popov, Branko N.

    Hybrid composites of polypyrrole (PPy) and silver vanadium oxide (SVO) used for lithium primary batteries were chemically synthesized by an oxidative polymerization of pyrrole monomer on the SVO surface in an acidic medium. The composite electrode exhibited higher discharge capacity and better rate capability as compared with the pristine SVO electrode. The improvement in electrochemical performance of the composite electrode was due to PPy which accommodates lithium ions and also enhances the SVO utilization. Chronoamperometric and ac-impedance measurements indicated that lithium intercalation proceeds under the mixed control by interfacial charge transfer and diffusion. The enhanced SVO utilization in the composite electrode results from a facilitated kinetics of interfacial charge transfer in the presence of PPy.

  6. Electrochemical performance of polypyrrole/silver vanadium oxide composite cathodes in lithium primary batteries

    Science.gov (United States)

    Anguchamy, Yogesh K.; Lee, Jong-Won; Popov, Branko N.

    Polypyrrole (PPy)/silver vanadium oxide (SVO) composite cathode materials were synthesized by polymerizing pyrrole onto the surface of pure SVO particles. Electrochemical characterization was carried out by performing galvanostatic discharge, pulse discharge and ac-impedance experiments. The composite electrode exhibited better performance than pristine SVO in all the experiments. The composite electrodes yielded a higher discharge capacity and a better pulse discharge capability when compared to the pristine SVO electrode. The pulse discharge and ac-impedance studies indicated that PPy forms an effective conductive network on the SVO surface and thereby reduces the particle-to-particle contact resistance and facilitates the interfacial charge transfer kinetics. To determine the thermal stability of the composite cathode, galvanostatic discharge and ac-impedance experiments were performed at different temperatures. The capacity increased with temperature due to enhanced charge transfer kinetics and low mass transfer limitations. The peak capacity was obtained at 60 °C, after which the performance degraded with any further increase in temperature.

  7. Electrochemical performance of polypyrrole/silver vanadium oxide composite cathodes in lithium primary batteries

    Energy Technology Data Exchange (ETDEWEB)

    Anguchamy, Yogesh K.; Lee, Jong-Won; Popov, Branko N. [Center for Electrochemical Engineering, Department of Chemical Engineering, University of South Carolina, Columbia, SC 29208 (United States)

    2008-09-15

    Polypyrrole (PPy)/silver vanadium oxide (SVO) composite cathode materials were synthesized by polymerizing pyrrole onto the surface of pure SVO particles. Electrochemical characterization was carried out by performing galvanostatic discharge, pulse discharge and ac-impedance experiments. The composite electrode exhibited better performance than pristine SVO in all the experiments. The composite electrodes yielded a higher discharge capacity and a better pulse discharge capability when compared to the pristine SVO electrode. The pulse discharge and ac-impedance studies indicated that PPy forms an effective conductive network on the SVO surface and thereby reduces the particle-to-particle contact resistance and facilitates the interfacial charge transfer kinetics. To determine the thermal stability of the composite cathode, galvanostatic discharge and ac-impedance experiments were performed at different temperatures. The capacity increased with temperature due to enhanced charge transfer kinetics and low mass transfer limitations. The peak capacity was obtained at 60 C, after which the performance degraded with any further increase in temperature. (author)

  8. Prototype production of the scintigram viewer (SVO-1)

    International Nuclear Information System (INIS)

    Oyamada, Hiyoshimaru

    1975-01-01

    ''Scintigram Viewer'', SVO-1, is designed for reading the scintigram films by enhancing contrast of the pictures. This is composed of a light source, AKAI CVC-150 TV camera (with a zoom lens, Fujinon TV.Z, f:2), AKAI VCS-150 camera control unit and color TV(Sony, Trinitron CVM-1840). The light source is set in a box which has a side-window where the scintigram film is set. The light coming through the film is caught by TV camera where red and blue light are separated, leaving green light not affected. These lights are then sent to AKAI VCS-150 where the gains for red and blue can be adjusted to desirable color as the operator likes for display. After these manual processings, the scintigram film is shown on the color TV. The contrast enhancement can be done by adjusting either picture control on the TV panel or diaphragm of TV camera/or both, and the defocusing can be easily done by changing the focus of the lens. Because the TV camera has a zoom lens as mentioned above, either whole picture or enlarged picture of one area on the film can be displayed. Initially, the author designed this machine to find out cold areas which were easily overlooked by the ordinary manner on the original films. However, after examining many scintigram films by this technique it was found that the search for the hot areas was more suitable with this machine and the whole body bone scintigram was the best so far. For example, the metastatic bone lesion which is not definite on the original sicntigram by nacked eyes can be easily pointed out on the color TV after the abovementioned processings. Now, this machine is working very well and is an important accessory for our daily work. (auth.)

  9. Processing, characterization, and bactericidal activity of undoped and silver-doped vanadium oxides

    Energy Technology Data Exchange (ETDEWEB)

    Tousley, M.E.; Wren, A.W.; Towler, M.R. [Inamori School of Engineering, Alfred University, Alfred, NY 14803 (United States); Mellott, N.P., E-mail: mellott@alfred.edu [Inamori School of Engineering, Alfred University, Alfred, NY 14803 (United States)

    2012-12-14

    Vanadium oxide (V) and silver-doped vanadium oxide (Ag-V) powders were prepared via sol-gel processing. Structural evolution and bactericidal activity was examined as a function of temperature ranging from 250, 350, 450 and 550 Degree-Sign C. Powders were characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and Raman spectroscopy. Results from all techniques showed vanadium pentoxide (V{sub 2}O{sub 5}) is the predominant phase regardless of heat treatment temperature or the addition of silver (Ag). XRD analysis suggests Ag is present as AgCl in samples heat treated to 250, 350, and 450 Degree-Sign C and as AgV{sub 6}O{sub 15} at 550 Degree-Sign C. Bactericidal activity was evaluated against Escherichia coli using the agar disk diffusion method considering both Ag-V and undoped, V powders. While the addition of Ag significantly increased bactericidal properties, the specific Ag valency, or crystal structure and morphology formed at higher temperatures, had little effect on functionality. -- Highlights: Black-Right-Pointing-Pointer Vanadium and silver-doped vanadium oxide powders were prepared via sol-gel. Black-Right-Pointing-Pointer Powders were characterized using advanced, complementary structural techniques. Black-Right-Pointing-Pointer Bactericidal activity was evaluated against E. coli. Black-Right-Pointing-Pointer Both vanadium and silver doped vanadium oxide show bactericidal activity.

  10. Space volcano observatory (SVO): a metric resolution system on-board a micro/mini-satellite

    Science.gov (United States)

    Briole, P.; Cerutti-Maori, G.; Kasser, M.

    2017-11-01

    1500 volcanoes on the Earth are potentially active, one third of them have been active during this century and about 70 are presently erupting. At the beginning of the third millenium, 10% of the world population will be living in areas directly threatened by volcanoes, without considering the effects of eruptions on climate or air-trafic for example. The understanding of volcanic eruptions, a major challenge in geoscience, demands continuous monitoring of active volcanoes. The only way to provide global, continuous, real time and all-weather information on volcanoes is to set up a Space Volcano Observatory closely connected to the ground observatories. Spaceborne observations are mandatory and implement the ground ones as well as airborne ones that can be implemented on a limited set of volcanoes. SVO goal is to monitor both the deformations and the changes in thermal radiance at optical wavelengths from high temperature surfaces of the active volcanic zones. For that, we propose to map at high resolution (1 to 1,5 m pixel size) the topography (stereoscopic observation) and the thermal anomalies (pixel-integrated temperatures above 450°C) of active volcanic areas in a size of 6 x 6 km to 12 x 12 km, large enough for monitoring most of the target features. A return time of 1 to 3 days will allow to get a monitoring useful for hazard mitigation. The paper will present the concept of the optical payload, compatible with a micro/mini satellite (mass in the range 100 - 400 kg), budget for the use of Proteus platform in the case of minisatellite approach will be given and also in the case of CNES microsat platform family. This kind of design could be used for other applications like high resolution imagery on a limited zone for military purpose, GIS, evolution cadaster…

  11. High rate capability of lithium/silver vanadium oxide cells

    International Nuclear Information System (INIS)

    Takeuchi, E.S.; Zelinsky, M.A.; Keister, P.

    1986-01-01

    High rate characteristics of the lithium/silver vanadium oxide system were investigated in test cells providing four different limiting surface areas. The cells were tested by constant current and constant resistance discharge with current densities ranging from 0.04 to 6.4 mA/cm/sup 2/. The maximum current density under constant resistance and constant current discharges which would deliver 50% of theoretical capacity was determined. The ability of the cells to deliver high current pulses was evaluated by application of 10 second pulses with current densities ranging from 3 to 30 mA/cm/sup 2/. The voltage delay characteristics of the cells were determined after 1 to 3 months of storage at open circuit voltage or under low level background currents. The volumetric and gravimetric energy density of the SVO system is compared to other cathode materials

  12. Electrode for a lithium cell

    Science.gov (United States)

    Thackeray, Michael M [Naperville, IL; Vaughey, John T [Elmhurst, IL; Dees, Dennis W [Downers Grove, IL

    2008-10-14

    This invention relates to a positive electrode for an electrochemical cell or battery, and to an electrochemical cell or battery; the invention relates more specifically to a positive electrode for a non-aqueous lithium cell or battery when the electrode is used therein. The positive electrode includes a composite metal oxide containing AgV.sub.3O.sub.8 as one component and one or more other components consisting of LiV.sub.3O.sub.8, Ag.sub.2V.sub.4O.sub.11, MnO.sub.2, CF.sub.x, AgF or Ag.sub.2O to increase the energy density of the cell, optionally in the presence of silver powder and/or silver foil to assist in current collection at the electrode and to improve the power capability of the cell or battery.

  13. Reduced deep regional cerebral venous oxygen saturation in hemodialysis patients using quantitative susceptibility mapping.

    Science.gov (United States)

    Chai, Chao; Liu, Saifeng; Fan, Linlin; Liu, Lei; Li, Jinping; Zuo, Chao; Qian, Tianyi; Haacke, E Mark; Shen, Wen; Xia, Shuang

    2018-02-01

    Cerebral venous oxygen saturation (SvO 2 ) is an important indicator of brain function. There was debate about lower cerebral oxygen metabolism in hemodialysis patients and there were no reports about the changes of deep regional cerebral SvO 2 in hemodialysis patients. In this study, we aim to explore the deep regional cerebral SvO 2 from straight sinus using quantitative susceptibility mapping (QSM) and the correlation with clinical risk factors and neuropsychiatric testing . 52 hemodialysis patients and 54 age-and gender-matched healthy controls were enrolled. QSM reconstructed from original phase data of 3.0 T susceptibility-weighted imaging was used to measure the susceptibility of straight sinus. The susceptibility was used to calculate the deep regional cerebral SvO 2 and compare with healthy individuals. Correlation analysis was performed to investigate the correlation between deep regional cerebral SvO 2 , clinical risk factors and neuropsychiatric testing. The deep regional cerebral SvO 2 of hemodialysis patients (72.5 ± 3.7%) was significantly lower than healthy controls (76.0 ± 2.1%) (P deep regional cerebral SvO 2 in patients. The Mini-Mental State Examination (MMSE) scores of hemodialysis patients were significantly lower than healthy controls (P deep regional cerebral SvO 2 did not correlate with MMSE scores (P = 0.630). In summary, the decreased deep regional cerebral SvO 2 occurred in hemodialysis patients and dialysis duration, parathyroid hormone, hematocrit, hemoglobin and red blood cell may be clinical risk factors.

  14. In-vivo continuous monitoring of mixed venous oxygen saturation by photoacoustic transesophageal echocardiography (Conference Presentation)

    Science.gov (United States)

    Li, Li; Subramaniam, Balachundhar; Aguirre, Aaron D.; Andrawes, Michael N.; Tearney, Guillermo J.

    2016-02-01

    Mixed venous oxygen saturation (SvO2), measured from pulmonary arteries, is a gold-standard measure of the dynamic balance between the oxygen supply and demand in the body. In critical care, continuous monitoring of SvO2 plays a vital role in early detection of circulatory shock and guiding goal-oriented resuscitation. In current clinical practice, SvO2 is measured by invasive pulmonary artery catheters (PAC), which are associated with a 10% risk of severe complications. To address the unmet clinical need for a non-invasive SvO2 monitor, we are developing a new technology termed photoacoustic transesophageal echocardiography (PA-TEE). PA-TEE integrates transesophageal echocardiography with photoacoustic oximetry, and enables continuous assessment of SvO2 through an esophageal probe that can be inserted into the body in a minimally invasive manner. We have constructed a clinically translatable PA-TEE prototype, which features a mobile OPO laser, a modified ultrasonography console and a dual-modality esophageal probe. Comprised of a rotatable acoustic array detector, a flexible optical fiber bundle and a light-integrating acoustic lens, the oximetric probe has an outer diameter smaller than 15 mm and will be tolerable for most patients. Through custom-made C++/Qt software, our device acquires and displays ultrasonic and photoacoustic images in real time to guide the deployment of the probe. SvO2 is calculated on-line and updated every second. PA-TEE has now been used to evaluate SvO2 in living swine. Our findings show that changing the fraction of oxygen in the inspired gas modulates SvO2 measured by PA-TEE. Statistic comparison between SvO2 measurements from PA-TEE in vivo the gold-standard laboratorial analysis on blood samples drawn from PACs will be presented.

  15. Saturação venosa central e mista de oxigênio no choque séptico: existe diferença clinicamente relevante? Central and mixed venous oxygen saturation in septic shock: is there a clinically relevant difference?

    Directory of Open Access Journals (Sweden)

    Flavia Ribeiro Machado

    2008-12-01

    Full Text Available INTRODUÇÃO: A medida da saturação venosa central de oxigênio (SvcO2 tem sido proposta como alternativa a saturação venosa mista (SvO2, com grau de concordância variável nos dados atualmente disponíveis. Esse estudo objetivou avaliar as possíveis diferenças entre a SvO2 e a SvcO2 ou saturação venosa atrial de oxigênio (SvaO2, com ênfase na interferência do débito cardíaco, e o impacto delas no manejo clínico do paciente séptico. MÉTODOS: Estudo prospectivo observacional em pacientes com choque séptico monitorizados com cateter de artéria pulmonar. Foi obtido sangue simultaneamente para determinação da SvcO2, SvO2 e SvaO2. Realizado testes de correlação linear (significativos se pINTRODUCTION: Central venous oxygen saturation (SvcO2 has been proposed as an alternative for mixed venous oxygen saturation (SvO2, with a variable level of acceptance according to available data. This study aimed to evaluate possible differences between SvO2 and SvcO2 or atrial venous saturation (SvaO2, with emphasis on the role of cardiac output and their impact on clinical management of the septic patient. METHODS: This is an observational, prospective study of patients with septic shock monitored by pulmonary artery catheter. Blood was obtained simultaneously for SvcO2, SvO2 and SvaO2 determination. Linear correlation (significant if p<0.05 and agreement analysis (Bland-Altman were performed with samples and subgroups according to cardiac output. Moreover, agreement about clinical management based on these samples was evaluated. RESULTS: Sixty one measurements from 23 patients were obtained, median age of 65.0 (49.0-75.0 years and mean APACHE II of 27.7±6.3. Mean values of SvO2, SvcO2 and SvaO2 were 72.20±8.26%, 74.61±7.60% and 74.64±8.47%. Linear correlation test showed a weak correlation between SvO2 and SvcO2 (r=0.61, p<0.0001 and also between SvO2 and SvaO2 (r=0.70, p<0.0001. Agreements between SvcO2/SvO2 and SvaO2/SvO2 were -2.40

  16. Comparison of actual oxygen delivery kinetics to those predicted by mathematical modeling following stage 1 palliation just prior to superior cavopulmonary anastomosis.

    Science.gov (United States)

    Yuki, Koichi; DiNardo, James A

    2015-02-01

    Optimizing systemic oxygen delivery (DO2) and hemodynamics in children with hypoplastic left heart syndrome (HLHS) is a clinical challenge. Mathematical modeling of the HLHS circulation has been used to determine the relationship between oxygen kinetic parameters and DO2 and to determine how DO2 might be optimized. The model demonstrates that neither arterial oxygen saturation (SaO2) nor mixed venous oxygen saturation (SvO2) alone accurately predicts DO2. Oxygen delivery kinetics predicted by previously described mathematical modeling were compared with actual patients' hemodynamic data. We sought to determine which patient derived parameters correlated best with DO2. Patients with HLHS who underwent cardiac catheterization prior to surgery to create a superior cavopulmonary anastomosis from 2007 to 2011 were identified. Hemodynamic data obtained were compared with the data derived from the mathematical model. Correlations between SaO2, SvO2, SaO2-SvO2, SaO2/(SaO2-SvO2), pulmonary-to-systemic blood flow ratio (Qp/Qs), and DO2 were evaluated using both linear and nonlinear analyses, and R(2) was calculated. Patients' data fit most aspects of the mathematical model. DO2 had the best correlation with SaO2/(SaO2-SvO2; R(2) = 0.8755) followed by SaO2 -SvO2 (R(2) = 0.8063), while SaO2 or SvO2 alone did not demonstrate a significant correlation as predicated by the mathematical model (R(2) = 0.09564 and 0.4831, respectively). SaO2/(SaO2 -SvO2) would be useful clinically to track changes in DO2 that occur with changes in patient condition or with interventions. © 2014 John Wiley & Sons Ltd.

  17. Is it environmentally advantageous to use vegetable oil directly as biofuel instead of converting it to biodiesel?

    International Nuclear Information System (INIS)

    Esteban, Bernat; Baquero, Grau; Puig, Rita; Riba, Jordi-Roger; Rius, Antoni

    2011-01-01

    The oil price instability and the measures taken to reduce the increase in greenhouse gas emissions are the main factors promoting the development and use of environmentally friendly energies. From an energy efficiency point of view, biofuels constitute a renewable energy source and its use helps to reduce energy dependency on fossil fuels. The most used biofuels for transport worldwide are biodiesel (BD) and bioethanol. However, there are other options such as straight vegetable oil (SVO). SVO can be small-scale produced in local cooperatives through pressing, filtering and conditioning processes which are much simpler than the ones required for BD production. In this study a comparative life cycle assessment (LCA) of two biofuels obtained from Spanish rapeseed, namely small-scale SVO and large-scale BD, is performed. The LCA methodology allows the two biofuels' production and their rate of consumption in a vehicle (a truck) to be compared. In this manner, it is possible to assess which is environmentally advantageous: to use SVO directly as biofuel or to convert it to BD. Moreover, LCA is used in the study to calculate the energy return on investment index (EROI) and an energy conversion ratio to evaluate which biofuel is more energy efficient. The obtained results show the environmental benefits of using SVO instead of BD by analyzing representative impact categories defined by the CML and EDIP methods. A sensitivity analysis has also been conducted. EROI indexes for SVO and BD production show a clear preference for SVO as compared to BD.

  18. Avaliação da implantação dos Serviços de Verificação de Óbito em Pernambuco, 2012: estudo de casos múltiplos

    Directory of Open Access Journals (Sweden)

    Barbara Araújo Silva de Azevedo

    Full Text Available Resumo OBJETIVO: avaliar a implantação dos Serviços de Verificação de Óbito (SVO no estado de Pernambuco, Brasil, em 2012. MÉTODOS: pesquisa avaliativa de análise de implantação; elaborou-se modelo lógico e matriz de julgamento; utilizaram-se dados primários (observação direta e entrevistas e secundários; a avaliação do grau de implantação foi baseada em indicadores de estrutura e processo, relacionados aos resultados e confrontados com o modelo lógico. RESULTADOS: os SVO de Recife e Caruaru alcançaram 89,0% e 82,0% dos valores esperados, respectivamente, e foram considerados como 'Parcialmente Implantado Avançado', de forma coerente com os indicadores de resultado aferidos; os componentes Coleta de Informação e Diagnóstico Nosológico/Etiológico obtiveram grau 'Implantado' nos SVO/Recife e SVO/Caruaru; o componente Ensino e Pesquisa obteve o grau 'Implantado' somente no SVO/Recife. CONCLUSÃO: houve semelhança no grau de implantação nos dois serviços; o maior grau de implantação do componente Ensino e Pesquisa no SVO/Recife revela a importância da cooperação técnico-acadêmica.

  19. Modeling agent's preferences by its designer's social value orientation

    Science.gov (United States)

    Zuckerman, Inon; Cheng, Kan-Leung; Nau, Dana S.

    2018-03-01

    Human social preferences have been shown to play an important role in many areas of decision-making. There is evidence from the social science literature that human preferences in interpersonal interactions depend partly on a measurable personality trait called, Social Value Orientation (SVO). Automated agents are often written by humans to serve as their delegates when interacting with other agents. Thus, one might expect an agent's behaviour to be influenced by the SVO of its human designer. With that in mind, we present the following: first, we explore, discuss and provide a solution to the question of how SVO tests that were designed for humans can be used to evaluate agents' social preferences. Second, we show that in our example domain there is a medium-high positive correlation between the social preferences of agents and their human designers. Third, we exemplify how the SVO information of the designer can be used to improve the performance of some other agents playing against those agents, and lastly, we develop and exemplify the behavioural signature SVO model which allows us to better predict performances when interactions are repeated and behaviour is adapted.

  20. Continuous distending pressure effects on variables contributing to oxygenation in healthy and ARDS model pigs during HFOV

    Science.gov (United States)

    Laviola, Marianna; Hajny, Ondrej; Roubik, Karel

    2014-10-01

    High frequency oscillatory ventilation (HFOV) is an alternative mode of mechanical ventilation. HFOV has been shown to provide adequate ventilation and oxygenation in acute respiratory distress syndrome (ARDS) patients and may represent an effective lung-protective ventilation in patients where conventional ventilation is failing. The aim of this study is to evaluate effects of continuous distending pressure (CDP) on variables that contribute to the oxygenation in healthy and ARDS lung model pigs. Methods. In order to simulate a lung disease, lung injury was induced by lavage with normal saline with detergent in three pigs. HFOV ventilation was applied before and after the lung lavage. CDP was stepwise increased by 2 cmH2O, until the maximum CDP (before the lung lavage 32 cmH2O and after the lung lavage 42 cmH2O) and then it was stepwise decreased by 2 cmH2O to the initial value. In this paper we analyzed the following parameters acquired during our experiments: partial pressure of oxygen in arterial blood (PaO2), cardiac output (CO) and mixed venous blood oxygen saturation (SvO2). In order to find how both PaO2 and CO affected SvO2 during the increase of CDP before and after lavage, a nonlinear regression fitting of the response in SvO2 on the predictors (PaO2 and CO) was implemented. Results. Before the lavage, with increasing of CDP, PaO2 remained constant, CO strongly decreased and SvO2 slightly decreased. After the lavage, with increasing of CDP, PaO2 strongly increased, CO decreased and SvO2 increased. So, development of SvO2 followed the PaO2 and CO trends. Changes in PaO2 and CO occur at decisive CDP step and it was much higher after the lung lavage compared to the healthy lungs. The implemented nonlinear model gives a good goodness of fitting in all three pigs. The values of PaO2 and CO estimated coefficients changed at the same decisive step of CDP identified by the trends. Also the algorithm identified a CDP step much higher after the lung lavage

  1. Severe sepsis and septic shock [author's reply

    NARCIS (Netherlands)

    Angus, Derek C.; van der Poll, Tom

    2013-01-01

    To the Editor: We would like to address two potentially confusing issues concerning venous oxygen saturation (Svo(2)) as presented in Table 1 of the review by Angus and van der Poll (Aug. 29 issue).(1) First, Table 1 suggests that Svo(2) is raised in sepsis, severe sepsis, and septic shock.

  2. The relationship between heart rate and rate of oxygen consumption in Galapagos marine iguanas (Amblyrhynchus cristatus) at two different temperatures.

    Science.gov (United States)

    Butler, Patrick J; Frappell, Peter B; Wang, Tobias; Wikelski, Martin

    2002-07-01

    To enable the use of heart rate (fH) for estimating field metabolic rate (FMR) in free-ranging Galapagos marine iguanas Amblyrhynchus cristatus, we determined the relationships between fH and mass-specific rate of oxygen consumption (sVO2) in seven iguanas before and during exercise on a treadmill and during the post-exercise period. The experiments were conducted at 27 and 35 degrees C, which are the temperatures that represent the lowest and highest average body temperatures of these animals in the field during summer. There were linear and significant relationships between fH and sVO2 at both temperatures (r(2)=0.86 and 0.91 at 27 degrees C and 36 degrees C, respectively). The slopes of the two regression lines did not differ, but there were significant differences in their intercepts. Thus, while heart rate can be used to predict FMR, the effects of temperature on the intercept of the regression must be taken into account when converting fH to sVO2. On the basis of our data, this can be achieved by applying the following formula: sVO2=0.0113fH-0.2983Q(10)((T(b)-27)/10). The increase in sVO2 with elevated body temperature results from an increase in fH, with no significant change in mass-specific oxygen pulse (sO(2) pulse; cardiac stroke volume times the difference in oxygen content between arterial and mixed venous blood). However, during exercise at both temperatures, increases in fH are insufficient to provide all of the additional O(2) required and there are also significant increases in the sO(2) pulses. This creates the situation whereby the same fH at the two temperatures can represent different values of sVO2.

  3. Personality and Behavior in Social Dilemmas: Testing the Situational Strength Hypothesis and the Role of Hypothetical Versus Real Incentives.

    Science.gov (United States)

    Lozano, José H

    2016-02-01

    Previous research aimed at testing the situational strength hypothesis suffers from serious limitations regarding the conceptualization of strength. In order to overcome these limitations, the present study attempts to test the situational strength hypothesis based on the operationalization of strength as reinforcement contingencies. One dispositional factor of proven effect on cooperative behavior, social value orientation (SVO), was used as a predictor of behavior in four social dilemmas with varying degree of situational strength. The moderating role of incentive condition (hypothetical vs. real) on the relationship between SVO and behavior was also tested. One hundred undergraduates were presented with the four social dilemmas and the Social Value Orientation Scale. One-half of the sample played the social dilemmas using real incentives, whereas the other half used hypothetical incentives. Results supported the situational strength hypothesis in that no behavioral variability and no effect of SVO on behavior were found in the strongest situation. However, situational strength did not moderate the effect of SVO on behavior in situations where behavior showed variability. No moderating effect was found for incentive condition either. The implications of these results for personality theory and assessment are discussed. © 2014 Wiley Periodicals, Inc.

  4. Straight vegetable oil use in Micro-Gas Turbines: System adaptation and testing

    International Nuclear Information System (INIS)

    Prussi, M.; Chiaramonti, D.; Riccio, G.; Martelli, F.; Pari, L.

    2012-01-01

    Highlights: → The possibility to feed a Micro Gas Turbine with Straight Vegetable Oil (SVO) has been investigated. → Correlative analysis and CFD were used to model the effect of SVO characteristics on atomization and evaporation. → Minor modifications to a the commercial MGT were adopted. → Measured power output and specific fuel consumption were close to standard fuel, taking into account the LHV of SVO. → Emissions were higher than for standard fossil fuel but strongly affected by SVO temperature. -- Abstract: The aim of this research work is to investigate the use of straight vegetable sunflower oil (SFO), a liquid biofuel, in a Micro-Gas Turbine (MGT). Compared to conventional diesel engines, micro-gas turbines represent a very reliable, clean and performing small scale cogeneration technology. Commercial gas turbines have already been tested with unconventional fuels, such as biomass derived fuels; however, research work on using Straight Vegetable Oil (SVO) as fuel in MGTs are really scarce. The chemical and physical characteristics of SVO are different from fossil diesel oil and rather far from the common technical specifications for gas turbine liquid fuels, not only in terms of kinematic viscosity and Lower Heating Value, but also as regards other issues as contaminant levels and composition, fuel cold properties, ignition properties, etc. Therefore, particular attention has to be given to the atomization and evaporation phases, as these are the most critical steps to achieve stable and efficient long term operation. An analysis based on numerical correlations available from literature was initially adopted for the analysis of the atomization process, supported by CFD modeling to qualitatively investigate the flow pattern. Control parameters were revised and set so to produce a sunflower oil spray having evaporation time comparable to diesel, and minor adaptations to the fuel line were designed and installed on the MGT. Tests with blends and

  5. Simultaneous estimation of arterial and venous oxygen saturation using a camera

    Science.gov (United States)

    van Gastel, Mark; Liang, Hangbing; Stuijk, Sander; de Haan, Gerard

    2018-02-01

    Optical monitoring of arterial blood oxygenation, SpO2, using cameras has recently been shown feasible by measuring the relative amplitudes of the remotely sensed PPG waveforms captured at different wavelengths. SvO2 measures the venous blood oxygenation which together with SpO2 provides an indication of tissue oxygen consumption. In contrast to SpO2 it usually still requires a blood sample from a pulmonary artery catheter. In this work we present a method which suggests simultaneous estimation of SpO2 and SvO2 with a camera. Contrary to earlier work, our method does not require external cuffs leading to better usability and improved comfort. Since the arterial blood varies synchronously with the heart rate, all frequencies outside the heart rate band are typically filtered out for SpO2 measurements. For SvO2 estimation, we include intensity variations in the respiratory frequency range since respiration modulates venous blood due to intrathoracic pressure variations in the chest and abdomen. Consequently, under static conditions, the two dominant components in the PPG signals are respiration and pulse. By measuring the amplitude ratios of these components, it seems possible to monitor both SpO2 and SvO2 continuously. We asked healthy subjects to follow an auditory breathing pattern while recording the face and hand. Results show a difference in estimated SpO2 and SvO2 values in the range 5-30 percent for both anatomical locations, which is normal for healthy people. This continuous, non-contact, method shows promise to alert the clinician to a change in patient condition sooner than SpO2 alone.

  6. Developmental toxicity in flounder embryos exposed to crude oils derived from different geographical regions.

    Science.gov (United States)

    Jung, Jee-Hyun; Lee, Eun-Hee; Choi, Kwang-Min; Yim, Un Hyuk; Ha, Sung Yong; An, Joon Geon; Kim, Moonkoo

    2017-06-01

    Crude oils from distinct geographical regions have distinct chemical compositions, and, as a result, their toxicity may be different. However, developmental toxicity of crude oils derived from different geographical regions has not been extensively characterized. In this study, flounder embryos were separately exposed to effluents contaminated by three crude oils including: Basrah Light (BLO), Pyrenees (PCO), and Sakhalin Vityaz (SVO), in addition to a processed fuel oil (MFO-380), to measure developmental toxicity and for gene expressions. Each oil possessed a distinct chemical composition. Edema defect was highest in embryos exposed to PCO and MFO-380 that both have a greater fraction of three-ring PAHs (33% and 22%, respectively) compared to BLO and SVO. Observed caudal fin defects were higher in embryos exposed to SVO and MFO-380, which are both dominated by naphthalenes (81% and 52%, respectively). CYP1A gene expressions were also highest in embryos exposed to SVO and MFO-380. Higher incidence of cardiotoxicity and lower nkx 2.5 expression were detected in embryos exposed to PCO. Unique gene expression profiles were observed in embryos exposed to crude oils with distinct compositions. This study demonstrates that crude oils of different geographical origins with different compositional characteristics induce developmental toxicity to different degrees. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Human Health Exposure Assessment for Rocky Mountain Arsenal Study Area Evaluations. Volume 6-G. South Plants Study Area Exposure Assessment. Version 4.1

    Science.gov (United States)

    1990-09-01

    2 910 i~ (P32 4-5 Ahkm 03 CLOAN 20 04c6.~n 2 .Y .4DCPO 40 (VID) 03201 a- 4~n.Cd 147 24 ~- -Pb 58 I53 Ak66at 0.4 Zn 540 *CHPO 03 DCPV I 15 i. 0 oCPD o...9CHP oo 04 (V0) As 02 DCPD 10 (Vol "H1 21 OCPO 60+(SVO) 4-5 CHO50V)As 1100004 OCPD 4000 1 (VW 900 DCCPO 3000 (SVO) 9-10 4 (VO Cd 31 OCPD 300 +(V0) Z"r...76 OCPD 60 + (S VO) As I1100 Cd 14 Ng 160 As 31 9-10 BCHPD 600 (VOl No_ 6 9 OCPO 2010 (Vol 115-12.5 BCHPD 2 (vO) DCPO 900 + (SVO) Cd 1 3 Cd 2.5 Zn 61

  8. Does Social Value Orientation Theory Apply to Social Relations?

    Directory of Open Access Journals (Sweden)

    Patricia Danielle Lewis

    2017-03-01

    Full Text Available This research asks whether Social Value Orientations (SVOs apply to the social relations of exchange networks. SVO literature identifies three types of orientation to rational action, determined by how actors value outcomes to self and other. Only the individualist is the self-interested, rational actor previously seen in exchange networks. The prosocial actor seeks to maximize joint outcomes and equality whereas the competitor seeks to maximize differences between self and other. The competitor and individualist are frequently collapsed into a proself type. Whereas SVO research has focused on games and social dilemmas, this research places prosocials and proselfs in equal, weak, and strong power exchange structures. We show that, if SVO applies, the behaviors of proself and prosocial will be very different. Experimental results demonstrate, however, that prosocials’ actions in exchanges are indistinguishable from activities of proselfs.

  9. T2-prepared velocity selective labelling

    DEFF Research Database (Denmark)

    Alderliesten, Thomas; De Vis, Jill B; Lemmers, Petra M A

    2016-01-01

    2-BIOS correlated with SO2-NIRS (R(2)=0.41, p=0.002) and SvO2-T2-TRIR (R(2)=0.87, p=0.002). In addition, SO2-NIRS correlated with SvO2-T2-TRIR (R(2)=0.85, p=0.003) Frontal cerebral blood flow correlated with SO2-T2-BIOS (R(2)=0.21, p=0.04), but was not significant in relation to SO2-NIRS. DISCUSSION...

  10. Accommodation modulates the individual difference between objective and subjective measures of the final convergence step response.

    Science.gov (United States)

    Jainta, S; Hoormann, J; Jaschinski, W

    2009-03-01

    Measuring vergence eye movements with dichoptic nonius lines (subjectively) usually leads to an overestimation of the vergence state after a step response: a subjective vergence overestimation (SVO). We tried to reduce this SVO by presenting a vergence stimulus that decoupled vergence and accommodation during the step response, i.e. reduced the degree of 'forced vergence'. In a mirror-stereoscope, we estimated convergence step responses with nonius lines presented at 1000 ms after a disparity step-stimulus and compared it to objective recordings (EyeLink II; n = 6). We presented a vertical line, a cross/rectangle stimulus and a difference-of-gaussians (DOG) pattern. For 180 min arc step stimuli, the subjective measures revealed a larger final vergence response than the objective measure; for the vertical line this SVO was 20 min arc, while it was significantly smaller for the DOG (12 min arc). For 60 min arc step-responses, no overestimation was observed. Additionally, we measured accommodation, which changed more for the DOG-pattern compared with the line-stimulus; this relative increase correlated with the corresponding relative change of SVO (r = 0.77). Both findings (i.e. no overestimation for small steps and a weaker one for the DOG-pattern) reflect lesser conflicting demand on accommodation and vergence under 'forced-vergence' viewing; consequently, sensory compensation is reduced and subjective and objective measures of vergence step responses tend to agree.

  11. Straight Vegetable Oil as a Diesel Fuel?

    Energy Technology Data Exchange (ETDEWEB)

    None

    2014-01-01

    Biodiesel, a renewable fuel produced from animal fats or vegetable oils, is popular among many vehicle owners and fleet managers seeking to reduce emissions and support U.S. energy security. Questions sometimes arise about the viability of fueling vehicles with straight vegetable oil (SVO), or waste oils from cooking and other processes, without intermediate processing. But SVO and waste oils differ from biodiesel (and conventional diesel) in some important ways and are generally not considered acceptable vehicle fuels for large-scale or long-term use.

  12. Investigating hyperoxic effects in the rat brain using quantitative susceptibility mapping based on MRI phase.

    Science.gov (United States)

    Hsieh, Meng-Chi; Kuo, Li-Wei; Huang, Yun-An; Chen, Jyh-Horng

    2017-02-01

    To test whether susceptibility imaging can detect microvenous oxygen saturation changes, induced by hyperoxia, in the rat brain. A three-dimensional gradient-echo with a flow compensation sequence was used to acquire T2*-weighted images of rat brains during hyperoxia and normoxia. Quantitative susceptibility mapping (QSM) and QSM-based microvenous oxygenation venography were computed from gradient-echo (GRE) phase images and compared between the two conditions. Pulse oxygen saturation (SpO 2 ) in the cortex was examined and compared with venous oxygen saturation (SvO 2 ) estimated by QSM. Oxygen saturation change calculated by a conventional Δ R2* map was also compared with the ΔSvO 2 estimated by QSM. Susceptibilities of five venous and tissue regions were quantified separately by QSM. Venous susceptibility was reduced by nearly 10%, with an SvO 2 shift of 10% during hyperoxia. A hyperoxic effect, confirmed by SpO 2 measurement, resulted in an SvO 2 increase in the cortex. The ΔSvO 2 between hyperoxia and normoxia was consistent with what was estimated by the Δ R2* map in five regions. These findings suggest that a quantitative susceptibility map is a promising technique for SvO 2 measurement. This method may be useful for quantitatively investigating oxygenation-dependent functional MRI studies. Magn Reson Med 77:592-602, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

  13. Konfliktų valdymo gerinimas smulkiojo verslo organizacijose

    OpenAIRE

    Wasilewska, Lidia

    2008-01-01

    Šiame magistro baigiamajame darbe nagrinėjamos konfliktų valdymo gerinimo galimybės smulkaus verslo organizacijose (SVO). Jo tikslas yra atskleisti SVO kylančias konfliktines situacijas, jų priežastis, organizacinių konfliktų tipus, funkcijas bei pasekmes ir tuo pačiu pasiūlyti konfliktų valdymo strategijų organizacines prielaidas ir konstruktyvius jų sprendimo būdus. Pagrindinės šio darbo užduotys yra įvertinti bendrą konfliktų foną organizacijoje, išnagrinėti darbuotojų pasirenkamus sprendi...

  14. Social value orientation modulates the FRN and P300 in the chicken game.

    Science.gov (United States)

    Wang, Yiwen; Kuhlman, D Michael; Roberts, Kathryn; Yuan, Bo; Zhang, Zhen; Zhang, Wei; Simons, Robert F

    2017-07-01

    Social dilemmas pervade daily life, business, and politics. The manners in which these dilemmas are resolved depend in part on the personal characteristics of those involved. One such characteristic is Social Value Orientation (SVO), a trait-like predisposition to maximize cooperative (Pro-Social) or non-cooperative (Pro-Self) outcomes in social relationships. The present study investigated the role of SVO in modulating neural responses to outcomes in a type of social dilemma known as the Chicken Game. The Chicken Game models real-world situations involving two parties independently making a decision between cooperation and aggression. The EEG of Pro-Socials and Pro-Selfs was recorded while playing Chicken with a computer Opponent. Two ERP components were extracted: Feedback-Related Negativity (FRN) and the P300. Despite no behavioral differences in decision (i.e., cooperation, aggression), FRN results indicate that Pro-Socials experienced unreciprocated cooperation as the least desired outcome. Further, P300 results show a main effect for the Opponent's choice, such that the Opponent's cooperation was more salient than aggression. Additionally, an interaction between the Participant's and Opponent's choice showed that the effect for the Opponent's choice only occurred when the Participant chose cooperation. None of the results for P300 were moderated by SVO. For both ERP components, Pro-Selfs showed no differential responding to Chicken outcomes. In addition, FRN magnitude on trial n predicted choice on trial n+1 for Pro-Socials, but not for Pro-Selfs. P300 magnitude on trial n showed no relationship to choice on trial n+1. Results indicate that individual differences in SVO modulate FRN responses to Chicken outcomes, and that these neural reactions may have utility in predicting subsequent behaviors. For P300, there is no evidence of SVO modulation. Our general pattern of FRN responsiveness in Pro-Socials, but not in Pro-Selfs, is related to similar findings in f

  15. Hemodynamic differences between continual positive and two types of negative pressure ventilation.

    Science.gov (United States)

    Lockhat, D; Langleben, D; Zidulka, A

    1992-09-01

    In seven anesthetized dogs, ventilated with matching lung volumes, tidal volumes, and respiratory rates, we compared the effects on cardiac output (CO), arterial venous oxygen saturation difference (SaO2 - SVO2), and femoral and inferior vena cava pressure (1) intermittent positive pressure ventilation with positive end-expiratory pressure (CPPV); (2) iron-lung ventilation with negative end-expiratory pressure (ILV-NEEP); (3) grid and wrap ventilation with NEEP applied to the thorax and upper abdomen (G&W-NEEP). The values of CO and SaO2 - SVO2 with ILV-NEEP were similar to those with CPPV. However, with G&W-NEEP as compared with ILV-NEEP, mean CO was greater (2.9 versus 2.6 L/min, p = 0.02) and mean (SaO2 - SVO2) was lower (26.6% versus 28.3%, p = NS). Mean PFEM-IVC was higher with G&W-NEEP than with the other types of ventilation. We conclude that (1) ILV-NEEP is hemodynamically equivalent to CPPV and (2) G&W-NEEP has less adverse hemodynamic consequences. has less adverse hemodynamic consequences.

  16. Fault Detection and Isolation and Fault Tolerant Control of Wind Turbines Using Set-Valued Observers

    DEFF Research Database (Denmark)

    Casau, Pedro; Rosa, Paulo Andre Nobre; Tabatabaeipour, Seyed Mojtaba

    2012-01-01

    Research on wind turbine Operations & Maintenance (O&M) procedures is critical to the expansion of Wind Energy Conversion systems (WEC). In order to reduce O&M costs and increase the lifespan of the turbine, we study the application of Set-Valued Observers (SVO) to the problem of Fault Detection...... and Isolation (FDI) and Fault Tolerant Control (FTC) of wind turbines, by taking advantage of the recent advances in SVO theory for model invalidation. A simple wind turbine model is presented along with possible faulty scenarios. The FDI algorithm is built on top of the described model, taking into account...

  17. Evolução de variáveis hemodinâmicas e perfusionais durante o choque séptico experimental tratado com ressuscitação volêmica guiada por metas Hemodynamic and perfusion variables during experimental septic shock treated with goal-directed fluid resuscitation

    Directory of Open Access Journals (Sweden)

    Marcelo Park

    2011-09-01

    Full Text Available OBJETIVOS: Apesar da ressuscitação volêmica guiada por saturação venosa central de oxigênio (SvcO2 ser considerada atualmente padrão ouro no tratamento da sepse, poucos estudos caracterizaram o perfil evolutivo de variáveis hemodinâmicas e perfusionais durante esta abordagem terapêutica. Este estudo teve por objetivo descrever evolutivamente estes parâmetros durante o choque séptico experimental sem ressuscitação e após 12 horas de ressuscitação guiada por metas. MÉTODOS: Treze porcos (35-45 kg anestesiados foram submetidos a peritonite por inoculação fecal (0,75g/kg. Após desenvolverem hipotensão persistente, ambos os grupos receberam antibióticos e foram randomizados em dois grupos: controle (n=7, com suporte hemodinâmico otimizado para pressão venosa central entre 8-12mmHg, diurese acima de 0,5ml/kg/h e pressão arterial média maior que 65mmHg; e SvO2 (n=6, com os objetivos acima e SvO2 acima de 65%. As intervenções incluíram ringer lactato e noradrenalina nos 2 grupos e dobutamina no grupo SvO2. Os animais foram tratados durante doze horas ou óbito. RESULTADOS: A sepse não tratada associou-se a uma significante redução da SvO2, PvO2, débito cardíaco e pressão venosa central e aumento da diferença arterio-venosa da saturação de oxigênio e veno-arterial de CO2. Após ressuscitação, esses parâmetros foram corrigidos em ambos os grupos. A ressuscitação guiada por metas associou-se a um melhor perfil hemodinâmico caracterizado por maiores SvO2, débito cardíaco e pressão venosa central. CONCLUSÕES: A sepse não ressuscitada apresenta um perfil hemodinâmico sugestivo de hipovolemia, com piora perfusional e hemodinâmica revertida após ressuscitação volêmica. A ressuscitação guiada por metas associa-se a uma significante melhora dos parâmetros hemodinâmicos e perfusionaisOBJECTIVES: Although fluid resuscitation guided by central venous oxygen saturation (SvcO2 is currently considered the

  18. Economics of small-scale on-farm use of canola and soybean for biodiesel and straight vegetable oil biofuels

    International Nuclear Information System (INIS)

    Fore, Seth R.; Porter, Paul; Jordan, Nicholas; Lazarus, William

    2011-01-01

    While the cost competitiveness of vegetable oil-based biofuels (VOBB) has impeded extensive commercialization on a large-scale, the economic viability of small-scale on-farm production of VOBB is unclear. This study assessed the cost competitiveness of small-scale on-farm production of canola- [Brassica napus (L.)] and soybean-based [Glycine max (L.)] biodiesel and straight vegetable oil (SVO) biofuels in the upper Midwest at 2007 price levels. The effects of feedstock type, feedstock valuation (cost of production or market price), biofuel type, and capitalization level on the cost L -1 of biofuel were examined. Valuing feedstock at the cost of production, the cost of canola-based biodiesel ranged from 0.94 to 1.13 L -1 and SVO from 0.64 to 0.83 L -1 depending on capitalization level. Comparatively, the cost of soybean-based biodiesel and SVO ranged from 0.40 to 0.60 L -1 and from 0.14 to 0.33 L -1 , respectively, depending on capitalization level. Valuing feedstock at the cost of production, soybean biofuels were cost competitive whereas canola biofuels were not. Valuing feedstock at its market price, canola biofuels were more cost competitive than soybean-based biofuels, though neither were cost competitive with petroleum diesel. Feedstock type proved important in terms of the meal co-product credit, which decreased the cost of biodiesel by 1.39 L -1 for soybean and 0.44 L -1 for canola. SVO was less costly to produce than biodiesel due to reduced input costs. At a small scale, capital expenditures have a substantial impact on the cost of biofuel, ranging from 0.03 to 0.25 L -1 . (author)

  19. An Investigation of Viscosities, Calorific Values and Densities of Binary Biofuel Blends

    Directory of Open Access Journals (Sweden)

    Che Mat Sharzali

    2017-01-01

    Full Text Available Straight vegetable oil (SVO biofuel is a promising alternative to petroleum diesel fuel primarily due to its comparable physical properties to that of petroleum diesel fuel. However, the relatively higher viscosity of SVO limits its direct application in diesel engine. To resolve this issue, binary biofuel blends was introduced in this study to reduce the viscosity of SVO. In this work, a novel biofuel namely Melaleuca Cajuputi oil (MCO was used and blended with refined palm oil (RPO. A total of four blends with the mixing ratios of 20%, 40%, 50% and 60% of MCO were prepared. Various key properties of dynamic viscosity, calorific value and density of the blends were measured and benchmarked against the biodiesel standards based on ASTM D6751. It was found that viscosity and density of the blends decreased with the increase of MCO fraction. Meanwhile, the calorific value of the blends increased linearly as the MCO fraction increased. The blend of 40RPO60MCO was found to have comparable key properties of viscosity, calorific value and density to those of petroleum diesel fuel and ASTM D6751 standard.

  20. Negative Transfer Effects on L2 Word Order Processing.

    Science.gov (United States)

    Erdocia, Kepa; Laka, Itziar

    2018-01-01

    Does first language (L1) word order affect the processing of non-canonical but grammatical syntactic structures in second language (L2) comprehension? In the present study, we test whether L1-Spanish speakers of L2-Basque process subject-verb-object (SVO) and object-verb-subject (OVS) non-canonical word order sentences of Basque in the same way as Basque native speakers. Crucially, while OVS orders are non-canonical in both Spanish and Basque, SVO is non-canonical in Basque but is the canonical word order in Spanish. Our electrophysiological results showed that the characteristics of L1 affect the processing of the L2 even at highly proficient and early-acquired bilingual populations. Specifically, in the non-native group, we observed a left anterior negativity-like component when comparing S and O at sentence initial position and a P600 when comparing those elements at sentence final position. Those results are similar of those reported by Casado et al. (2005) for native speakers of Spanish indicating that L2-Basque speakers rely in their L1-Spanish when processing SVO-OVS word order sentences. Our results favored the competition model (MacWhinney, 1997).

  1. Effects of dexmedetomidine on microregional O2 balance during reperfusion after focal cerebral ischemia.

    Science.gov (United States)

    Chi, Oak Z; Grayson, Jeremy; Barsoum, Sylviana; Liu, Xia; Dinani, Aliraza; Weiss, Harvey R

    2015-01-01

    This study was performed to determine whether there is an association between microregional O2 balance and neuronal survival in cerebral ischemia-reperfusion using dexmedetomidine, an α2-adrenoreceptor agonist and a sedative. Rats were subjected to 1 hour middle cerebral artery occlusion and a 2-hour reperfusion. During reperfusion, normal saline (n = 14) or dexmedetomidine 1 μg/kg/minute (n = 14) was infused intravenously. At 2 hours of reperfusion, regional cerebral blood flow using (14)C-iodoantipyrine autoradiography, microregional arterial and venous (20-60 μm in diameter) O2 saturation (SvO2) using cryomicrospectrophotometry, and the size of cortical infarction were determined. Ischemia-reperfusion decreased microregional SvO2 (52.9 ± 3.7% vs. 61.1 ± .6%, P < .005) with increased variation or heterogeneity (P < .0001) with similar regional cerebral blood flow and O2 consumption. Dexmedetomidine during reperfusion decreased the heterogeneity of SvO2 that was analyzed with an analysis of variance (P < .01) and reported as coefficient of variation (100 × standard deviation/Mean) (11.8 vs. 16.4). The number of veins with O2 saturation less than 50% decreased with dexmedetomidine (13/80 vs. 27/81, P < .01). The percentage of cortical infarct in total cortex was smaller with dexmedetomidine (8.3 ± 2.2% vs. 12.6 ± 1.5%, P < .005). In the cerebral ischemic reperfused cortex, dexmedetomidine decreased the heterogeneity of SvO2 and the number of small veins with low O2 saturation suggesting improved microregional O2 supply/consumption balance. The improvement was accompanied by the reduced size of cortical infarction. Copyright © 2015 National Stroke Association. Published by Elsevier Inc. All rights reserved.

  2. Economics of small-scale on-farm use of canola and soybean for biodiesel and straight vegetable oil biofuels

    Energy Technology Data Exchange (ETDEWEB)

    Fore, Seth R.; Porter, Paul; Jordan, Nicholas [Department of Agronomy and Plant Genetics, 1991 Upper Buford Circle, Borlaug 411, The University of Minnesota, Saint Paul, Minnesota 55108 (United States); Lazarus, William [Department of Applied Economics, 231 Classroom Office Building, 1994 Buford Avenue, The University of Minnesota, Saint Paul, Minnesota 55108 (United States)

    2011-01-15

    While the cost competitiveness of vegetable oil-based biofuels (VOBB) has impeded extensive commercialization on a large-scale, the economic viability of small-scale on-farm production of VOBB is unclear. This study assessed the cost competitiveness of small-scale on-farm production of canola- [Brassica napus (L.)] and soybean-based [Glycine max (L.)] biodiesel and straight vegetable oil (SVO) biofuels in the upper Midwest at 2007 price levels. The effects of feedstock type, feedstock valuation (cost of production or market price), biofuel type, and capitalization level on the cost L{sup -1} of biofuel were examined. Valuing feedstock at the cost of production, the cost of canola-based biodiesel ranged from 0.94 to 1.13 L{sup -1} and SVO from 0.64 to 0.83 L{sup -1} depending on capitalization level. Comparatively, the cost of soybean-based biodiesel and SVO ranged from 0.40 to 0.60 L{sup -1} and from 0.14 to 0.33 L{sup -1}, respectively, depending on capitalization level. Valuing feedstock at the cost of production, soybean biofuels were cost competitive whereas canola biofuels were not. Valuing feedstock at its market price, canola biofuels were more cost competitive than soybean-based biofuels, though neither were cost competitive with petroleum diesel. Feedstock type proved important in terms of the meal co-product credit, which decreased the cost of biodiesel by 1.39 L{sup -1} for soybean and 0.44 L{sup -1} for canola. SVO was less costly to produce than biodiesel due to reduced input costs. At a small scale, capital expenditures have a substantial impact on the cost of biofuel, ranging from 0.03 to 0.25 L{sup -1}. (author)

  3. 'Multi-associations': predisposed to misinterpretation of peripheral tissue oxygenation and circulation in neonates

    International Nuclear Information System (INIS)

    Pichler, Gerhard; Pocivalnik, Mirjam; Pichler-Stachl, Elisabeth; Morris, Nicholas; Zotter, Heinz; Müller, Wilhelm; Urlesberger, Berndt; Riedl, Regina

    2011-01-01

    Interpretation of peripheral circulation in ill neonates is crucial but difficult. The aim was to analyse parameters potentially influencing peripheral oxygenation and circulation. In a prospective observational cohort study in 116 cardio-circulatory stable neonates, peripheral muscle near-infrared spectroscopy (NIRS) with venous occlusion was performed. Tissue oxygenation index (TOI), mixed venous oxygenation (SvO 2 ), fractional oxygen extraction (FOE), fractional tissue oxygen extraction (FTOE), haemoglobin flow (Hbflow), oxygen delivery (DO 2 ), oxygen consumption (VO 2 ), and vascular resistance (VR) were assessed. Correlation coefficients between NIRS parameters and demographic parameters (gestational age, birth weight, age, actual weight, diameter of calf, subcutaneous adipose tissue), monitoring parameters (heart rate, arterial oxygen saturation (SaO 2 ), mean blood pressure (MAP), core/peripheral temperature, central/peripheral capillary refill time) and laboratory parameters (haemoglobin concentration (Hb-blood), pCO 2 ) were calculated. All demographic parameters except for Hbflow and DO 2 correlated with NIRS parameters. Heart rate correlated with TOI, SvO 2 , VO 2 and VR. SaO 2 correlated with FOE/FTOE. MAP correlated with Hbflow, DO 2 , VO 2 and VR. Core temperature correlated with FTOE. Peripheral temperature correlated with all NIRS parameters except VO 2 . Hb-blood correlated with FOE and VR. pCO 2 levels correlated with TOI and SvO 2 . The presence of multiple interdependent factors associated with peripheral oxygenation and circulation highlights the difficulty in interpreting NIRS data. Nevertheless, these findings have to be taken into account when analysing peripheral oxygenation and circulation data

  4. The Oxytocin Receptor (OXTR) Contributes to Prosocial Fund Allocations in the Dictator Game and the Social Value Orientations Task

    Science.gov (United States)

    Israel, Salomon; Lerer, Elad; Shalev, Idan; Uzefovsky, Florina; Riebold, Mathias; Laiba, Efrat; Bachner-Melman, Rachel; Maril, Anat; Bornstein, Gary; Knafo, Ariel; Ebstein, Richard P.

    2009-01-01

    Background Economic games observe social decision making in the laboratory that involves real money payoffs. Previously we have shown that allocation of funds in the Dictator Game (DG), a paradigm that illustrates costly altruistic behavior, is partially determined by promoter-region repeat region variants in the arginine vasopressin 1a receptor gene (AVPR1a). In the current investigation, the gene encoding the related oxytocin receptor (OXTR) was tested for association with the DG and a related paradigm, the Social Values Orientation (SVO) task. Methodology/Principal Findings Association (101 male and 102 female students) using a robust-family based test between 15 single tagging SNPs (htSNPs) across the OXTR was demonstrated with both the DG and SVO. Three htSNPs across the gene region showed significant association with both of the two games. The most significant association was observed with rs1042778 (p = 0.001). Haplotype analysis also showed significant associations for both DG and SVO. Following permutation test adjustment, significance was observed for 2–5 locus haplotypes (pprosocial decision making converges with a large body of animal research showing that oxytocin is an important social hormone across vertebrates including Homo sapiens. Individual differences in prosocial behavior have been shown by twin studies to have a substantial genetic basis and the current investigation demonstrates that common variants in the oxytocin receptor gene, an important element of mammalian social circuitry, underlie such individual differences. PMID:19461999

  5. 'Multi-associations': predisposed to misinterpretation of peripheral tissue oxygenation and circulation in neonates.

    Science.gov (United States)

    Pichler, Gerhard; Pocivalnik, Mirjam; Riedl, Regina; Pichler-Stachl, Elisabeth; Morris, Nicholas; Zotter, Heinz; Müller, Wilhelm; Urlesberger, Berndt

    2011-08-01

    Interpretation of peripheral circulation in ill neonates is crucial but difficult. The aim was to analyse parameters potentially influencing peripheral oxygenation and circulation. In a prospective observational cohort study in 116 cardio-circulatory stable neonates, peripheral muscle near-infrared spectroscopy (NIRS) with venous occlusion was performed. Tissue oxygenation index (TOI), mixed venous oxygenation (SvO(2)), fractional oxygen extraction (FOE), fractional tissue oxygen extraction (FTOE), haemoglobin flow (Hbflow), oxygen delivery (DO(2)), oxygen consumption (VO(2)), and vascular resistance (VR) were assessed. Correlation coefficients between NIRS parameters and demographic parameters (gestational age, birth weight, age, actual weight, diameter of calf, subcutaneous adipose tissue), monitoring parameters (heart rate, arterial oxygen saturation (SaO(2)), mean blood pressure (MAP), core/peripheral temperature, central/peripheral capillary refill time) and laboratory parameters (haemoglobin concentration (Hb-blood), pCO(2)) were calculated. All demographic parameters except for Hbflow and DO(2) correlated with NIRS parameters. Heart rate correlated with TOI, SvO(2), VO(2) and VR. SaO(2) correlated with FOE/FTOE. MAP correlated with Hbflow, DO(2), VO(2) and VR. Core temperature correlated with FTOE. Peripheral temperature correlated with all NIRS parameters except VO(2). Hb-blood correlated with FOE and VR. pCO(2) levels correlated with TOI and SvO(2). The presence of multiple interdependent factors associated with peripheral oxygenation and circulation highlights the difficulty in interpreting NIRS data. Nevertheless, these findings have to be taken into account when analysing peripheral oxygenation and circulation data.

  6. SvO2 Trigger in Transfusion Strategy After Cardiac Surgery

    Science.gov (United States)

    2018-03-27

    Undergoing Nonemergent Cardiac Surgery; Central Venous Catheter on the Superior Vena Cava (to Perform ScVO2 Measure); Anemia (Blood Transfusion; Hemodynamic and Respiratory Stability; Bleeding Graded as Insignificant, Mild, Moderate of Universal Definition of Perioperative Bleeding

  7. Ten years of the Spanish Virtual Observatory

    Science.gov (United States)

    Solano, E.

    2015-05-01

    The main objective of the Virtual Observatory (VO) is to guarantee an easy and efficient access and analysis of the information hosted in astronomical archives. The Spanish Virtual Observatory (SVO) is a project that was born in 2004 with the goal of promoting and coordinating the VO-related activities at national level. SVO is also the national contact point for the international VO initiatives, in particular the International Virtual Observatory Alliance (IVOA) and the Euro-VO project. The project, led by Centro de Astrobiología (INTA-CSIC), is structured around four major topics: a) VO compliance of astronomical archives, b) VO-science, c) VO- and data mining-tools, and d) Education and outreach. In this paper I will describe the most important results obtained by the Spanish Virtual Observatory in its first ten years of life as well as the future lines of work.

  8. When Cars Hit Trucks and Girls Hug Boys: The Effect of Animacy on Word Order in Gestural Language Creation.

    Science.gov (United States)

    Kocab, Annemarie; Lam, Hannah; Snedeker, Jesse

    2018-04-01

    A well-known typological observation is the dominance of subject-initial word orders, SOV and SVO, across the world's languages. Recent findings from gestural language creation paradigms offer possible explanations for the prevalence of SOV. When asked to gesture transitive events with an animate agent and inanimate patient, gesturers tend to produce SOV order, regardless of their native language biases. Interestingly, when the patient is animate, gesturers shift away from SOV to use of other orders, like SVO and OSV. Two competing hypotheses have been proposed for this switch: the noisy channel account (Gibson et al., 2013) and the role conflict account (Hall, Mayberry, & Ferreira, 2013). We set out to distinguish between these two hypotheses, disentangling event reversibility and patient animacy, by looking at gestural sequences for events with two inanimate participants (inanimate-inanimate, reversible). We replicated the previous findings of a preference for SOV order when describing animate-inanimate, irreversible events as well as a decrease in the use of SOV when presented with animate-animate, reversible events. Accompanying the drop in SOV, in a novel condition we observed an increase in the use of SVO and OSV orders when describing events involving two animate entities. In sum, we find that the observed avoidance of SOV order in gestural language creation paradigms when the event includes an animate agent and patient is driven by the animacy of the participants rather than the reversibility of the event. We suggest that findings from gestural creation paradigms are not automatically linkable to spoken language typology. Copyright © 2017 Cognitive Science Society, Inc.

  9. Catalytic oxidation using nitrous oxide

    Directory of Open Access Journals (Sweden)

    Juan Carlos Beltran-Prieto

    2017-01-01

    Full Text Available Nitrous oxide is a very inert gas used generally as oxidant as it offers some advantage compared with other oxidants such as O2 but a considerably higher temperature (> 526 °C is often required. For particular cases such as the oxidation of sugar alcohols, especially for the oxidation of primary alcohols to aldehydes, N2O has the advantage over O2 of a higher reaction selectivity. In the present paper we present the modelling of oxidation reaction of sugar alcohols using an oxidizing agent in low concentrations, which is important to suppress subsequent oxidation reactions due to the very low residual concentrations of the oxidizing agent. For orientation experiments we chose nitrous oxide generated by thermal decomposition of ammonium nitrate. Kinetic modeling of the reaction was performed after determination of the differential equations that describe the system under study.

  10. Learning a Novel Pattern through Balanced and Skewed Input

    Science.gov (United States)

    McDonough, Kim; Trofimovich, Pavel

    2013-01-01

    This study compared the effectiveness of balanced and skewed input at facilitating the acquisition of the transitive construction in Esperanto, characterized by the accusative suffix "-n" and variable word order (SVO, OVS). Thai university students (N = 98) listened to 24 sentences under skewed (one noun with high token frequency) or…

  11. Phonological Advance Planning in Sentence Production

    Science.gov (United States)

    Oppermann, Frank; Jescheniak, Jorg D.; Schriefers, Herbert

    2010-01-01

    Our study addresses the scope of phonological advance planning during sentence production using a novel experimental procedure. The production of German sentences in various syntactic formats (SVO, SOV, and VSO) was cued by presenting pictures of the agents of previously memorized agent-action-patient scenes. To tap the phonological activation of…

  12. The Enzymatic Oxidation of Graphene Oxide

    Science.gov (United States)

    Kotchey, Gregg P.; Allen, Brett L.; Vedala, Harindra; Yanamala, Naveena; Kapralov, Alexander A.; Tyurina, Yulia Y.; Klein-Seetharaman, Judith; Kagan, Valerian E.; Star, Alexander

    2011-01-01

    Two-dimensional graphitic carbon is a new material with many emerging applications, and studying its chemical properties is an important goal. Here, we reported a new phenomenon – the enzymatic oxidation of a single layer of graphitic carbon by horseradish peroxidase (HRP). In the presence of low concentrations of hydrogen peroxide (~40 µM), HRP catalyzed the oxidation of graphene oxide, which resulted in the formation of holes on its basal plane. During the same period of analysis, HRP failed to oxidize chemically reduced graphene oxide (RGO). The enzymatic oxidation was characterized by Raman, UV-Vis, EPR and FT-IR spectroscopy, TEM, AFM, SDS-PAGE, and GC-MS. Computational docking studies indicated that HRP was preferentially bound to the basal plane rather than the edge for both graphene oxide and RGO. Due to the more dynamic nature of HRP on graphene oxide, the heme active site of HRP was in closer proximity to graphene oxide compared to RGO, thereby facilitating the oxidation of the basal plane of graphene oxide. We also studied the electronic properties of the reduced intermediate product, holey reduced graphene oxide (hRGO), using field-effect transistor (FET) measurements. While RGO exhibited a V-shaped transfer characteristic similar to a single layer of graphene that was attributed to its zero band gap, hRGO demonstrated a p-type semiconducting behavior with a positive shift in the Dirac points. This p-type behavior rendered hRGO, which can be conceptualized as interconnected graphene nanoribbons, as a potentially attractive material for FET sensors. PMID:21344859

  13. Correlação entre gasometria atrial direita e índice cardíaco no pós-operatório de cirurgia cardíaca Correlation between right atrial venous blood gasometry and cardiac index in cardiac surgery postoperative period

    Directory of Open Access Journals (Sweden)

    João Jackson Duarte

    2010-06-01

    Full Text Available OBJETIVO: Determinar a confiabilidade em se correlacionar o índice cardíaco com os dados fornecidos pela gasometria do sangue venoso atrial direito em pacientes submetidos à cirurgia cardíaca, durante o período pós-operatório. MÉTODOS: A partir das amostras de sangue arterial e venoso do átrio direito, colhidas no pós-operatório de cirurgia cardíaca, foram determinados os parâmetros de oxigênio do sangue venoso do átrio direito. Estes parâmetros foram então comparados com o índice cardíaco determinado pela termodiluição. RESULTADOS: Houve boa correlação entre a saturação de oxigênio do sangue venoso do átrio direito (SvO2, diferença artério-venosa do conteúdo de oxigênio do sangue colhido no átrio direito e o índice cardíaco aferido pela termodiluição, com boa sensibilidade e especificidade e alto valor preditivo positivo e negativo. A pressão do sangue do átrio direito (PvO2 apresentou baixa sensibilidade na estimativa de baixo débito cardíaco. CONCLUSÃO: No pós-operatório de cirurgia cardíaca, a SvO2e a diferença artério-venosa do conteúdo de oxigênio (C(avO2 apresentaram-se como parâmetros confiáveis correlacionados a baixo débito cardíaco. A PvO2 foi pouco sensível no diagnóstico de baixo débito no pós-operatório de cirurgia cardíaca.OBJECTIVE: To determine, even during postoperative period, the confiability of the cardiac index correlate with the data data given by a central atrial venous blood gasometry in patients who underwent cardiac surgery. METHODS: From the sample of arterial and venous blood of right atrium gathered in postoperative of cardiac surgery, it was determinated the hemoglobin concentration and the gasometric study through what was observed of the venous oxygen saturation (SvO2 and the partial pressure of oxygen from venous blood gathered in right atrium (PvO2, add to the calculation of artery-venous difference of the oxygen content - radial artery / right atrium (C

  14. The oxytocin receptor (OXTR contributes to prosocial fund allocations in the dictator game and the social value orientations task.

    Directory of Open Access Journals (Sweden)

    Salomon Israel

    Full Text Available BACKGROUND: Economic games observe social decision making in the laboratory that involves real money payoffs. Previously we have shown that allocation of funds in the Dictator Game (DG, a paradigm that illustrates costly altruistic behavior, is partially determined by promoter-region repeat region variants in the arginine vasopressin 1a receptor gene (AVPR1a. In the current investigation, the gene encoding the related oxytocin receptor (OXTR was tested for association with the DG and a related paradigm, the Social Values Orientation (SVO task. METHODOLOGY/PRINCIPAL FINDINGS: Association (101 male and 102 female students using a robust-family based test between 15 single tagging SNPs (htSNPs across the OXTR was demonstrated with both the DG and SVO. Three htSNPs across the gene region showed significant association with both of the two games. The most significant association was observed with rs1042778 (p = 0.001. Haplotype analysis also showed significant associations for both DG and SVO. Following permutation test adjustment, significance was observed for 2-5 locus haplotypes (p<0.05. A second sample of 98 female subjects was subsequently and independently recruited to play the dictator game and was genotyped for the three significant SNPs found in the first sample. The rs1042778 SNP was shown to be significant for the second sample as well (p = 0.004, Fisher's exact test. CONCLUSIONS: The demonstration that genetic polymorphisms for the OXTR are associated with human prosocial decision making converges with a large body of animal research showing that oxytocin is an important social hormone across vertebrates including Homo sapiens. Individual differences in prosocial behavior have been shown by twin studies to have a substantial genetic basis and the current investigation demonstrates that common variants in the oxytocin receptor gene, an important element of mammalian social circuitry, underlie such individual differences.

  15. Moderating Effects of Social Value Orientation on the Effect of Social Influence in Prosocial Decisions.

    Science.gov (United States)

    Wei, Zhenyu; Zhao, Zhiying; Zheng, Yong

    2016-01-01

    Prosocial behaviors are susceptible to individuals' preferences regarding payoffs and social context. In the present study, we combined individual differences with social influence and attempted to discover the effect of social value orientation (SVO) and social influence on prosocial behavior in a trust game and a dictator game. Prosocial behavior in the trust game could be motivated by strategic considerations whereas individuals' decisions in the dictator game could be associated with their social preference. In the trust game, prosocials were less likely than proselfs to conform to the behavior of other group members when the majority of group members distrusted the trustee. In the dictator game, the results of the three-way ANOVA indicated that, irrespective of the type of offer, in contrast to proselfs, prosocials were influenced more by others' generous choices than their selfish choices, even if the selfish choices were beneficial to themselves. The overall results demonstrated that the effect of social influence appears to depend on individuals' SVO: that is, prosocials tend to conform to prosocial rather than proself behaviors.

  16. The competing oxide and sub-oxide formation in metal-oxide molecular beam epitaxy

    International Nuclear Information System (INIS)

    Vogt, Patrick; Bierwagen, Oliver

    2015-01-01

    The hetero-epitaxial growth of the n-type semiconducting oxides β-Ga 2 O 3 , In 2 O 3 , and SnO 2 on c- and r-plane sapphire was performed by plasma-assisted molecular beam epitaxy. The growth-rate and desorbing flux from the substrate were measured in-situ under various oxygen to metal ratios by laser reflectometry and quadrupole mass spectrometry, respectively. These measurements clarified the role of volatile sub-oxide formation (Ga 2 O, In 2 O, and SnO) during growth, the sub-oxide stoichiometry, and the efficiency of oxide formation for the three oxides. As a result, the formation of the sub-oxides decreased the growth-rate under metal-rich growth conditions and resulted in etching of the oxide film by supplying only metal flux. The flux ratio for the exclusive formation of the sub-oxide (e.g., the p-type semiconductor SnO) was determined, and the efficiency of oxide formation was found to be the highest for SnO 2 , somewhat lower for In 2 O 3 , and the lowest for Ga 2 O 3 . Our findings can be generalized to further oxides that possess related sub-oxides

  17. The Syntax of Word Order Derivation and Agreement in Najrani Arabic: A Minimalist Analysis

    Science.gov (United States)

    Fakih, Abdul-Hafeed Ali; Al-Sharif, Hadeel Ali

    2017-01-01

    The paper aims to explore word order derivation and agreement in Najran Arabic (henceforth, NA) and examines the interaction between the NA data and Chomsky's (2001, 2005) Agree theory which we adopt in this study. The objective is to investigate how word order occurs in NA and provide a satisfactorily unified account of the derivation of SVO and…

  18. Tin-antimony oxide oxidation catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Berry, Frank J. [Open University, Department of Chemistry (United Kingdom)

    1998-12-15

    Tin-antimony oxide catalysts for the selective oxidation of hydrocarbons have been made by precipitation techniques. The dehydration of the amorphous dried precipitate by calcination at increasingly higher temperatures induces the crystallisation of a rutile-related tin dioxide-type phase and the segregation of antimony oxides which volatilise at elevated temperatures. The rutile-related tin dioxide-type phase contains antimony(V) in the bulk and antimony(III) in the surface. Specific catalytic activity for the oxidative dehydrogenation of butene to butadiene is associated with materials with large concentrations of antimony(III) in the surface.

  19. Sputtered tin oxide and titanium oxide thin films as alternative transparent conductive oxides

    Energy Technology Data Exchange (ETDEWEB)

    Boltz, Janika

    2011-12-12

    Alternative transparent conductive oxides to tin doped indium oxide have been investigated. In this work, antimony doped tin oxide and niobium doped titanium oxide have been studied with the aim to prepare transparent and conductive films. Antimony doped tin oxide and niobium doped titanium oxide belong to different groups of oxides; tin oxide is a soft oxide, while titanium oxide is a hard oxide. Both oxides are isolating materials, in case the stoichiometry is SnO{sub 2} and TiO{sub 2}. In order to achieve transparent and conductive films free carriers have to be generated by oxygen vacancies, by metal ions at interstitial positions in the crystal lattice or by cation doping with Sb or Nb, respectively. Antimony doped tin oxide and niobium doped titanium oxide films have been prepared by reactive direct current magnetron sputtering (dc MS) from metallic targets. The process parameters and the doping concentration in the films have been varied. The films have been electrically, optically and structurally analysed in order to analyse the influence of the process parameters and the doping concentration on the film properties. Post-deposition treatments of the films have been performed in order to improve the film properties. For the deposition of transparent and conductive tin oxide, the dominant parameter during the deposition is the oxygen content in the sputtering gas. The Sb incorporation as doping atoms has a minor influence on the electrical, optical and structural properties. Within a narrow oxygen content in the sputtering gas highly transparent and conductive tin oxide films have been prepared. In this study, the lowest resistivity in the as deposited state is 2.9 m{omega} cm for undoped tin oxide without any postdeposition treatment. The minimum resistivity is related to a transition to crystalline films with the stoichiometry of SnO{sub 2}. At higher oxygen content the films turn out to have a higher resistivity due to an oxygen excess. After post

  20. Oxidation kinetics of Si and SiGe by dry rapid thermal oxidation, in-situ steam generation oxidation and dry furnace oxidation

    Science.gov (United States)

    Rozé, Fabien; Gourhant, Olivier; Blanquet, Elisabeth; Bertin, François; Juhel, Marc; Abbate, Francesco; Pribat, Clément; Duru, Romain

    2017-06-01

    The fabrication of ultrathin compressively strained SiGe-On-Insulator layers by the condensation technique is likely a key milestone towards low-power and high performances FD-SOI logic devices. However, the SiGe condensation technique still requires challenges to be solved for an optimized use in an industrial environment. SiGe oxidation kinetics, upon which the condensation technique is founded, has still not reached a consensus in spite of various studies which gave insights into the matter. This paper aims to bridge the gaps between these studies by covering various oxidation processes relevant to today's technological needs with a new and quantitative analysis methodology. We thus address oxidation kinetics of SiGe with three Ge concentrations (0%, 10%, and 30%) by means of dry rapid thermal oxidation, in-situ steam generation oxidation, and dry furnace oxidation. Oxide thicknesses in the 50 Å to 150 Å range grown with oxidation temperatures between 850 and 1100 °C were targeted. The present work shows first that for all investigated processes, oxidation follows a parabolic regime even for thin oxides, which indicates a diffusion-limited oxidation regime. We also observe that, for all investigated processes, the SiGe oxidation rate is systematically higher than that of Si. The amplitude of the variation of oxidation kinetics of SiGe with respect to Si is found to be strongly dependent on the process type. Second, a new quantitative analysis methodology of oxidation kinetics is introduced. This methodology allows us to highlight the dependence of oxidation kinetics on the Ge concentration at the oxidation interface, which is modulated by the pile-up mechanism. Our results show that the oxidation rate increases with the Ge concentration at the oxidation interface.

  1. Optical properties and electronic transitions of zinc oxide, ferric oxide, cerium oxide, and samarium oxide in the ultraviolet and extreme ultraviolet

    DEFF Research Database (Denmark)

    Pauly, N; Yubero, F; Espinós, J P

    2017-01-01

    Optical properties and electronic transitions of four oxides, namely zinc oxide, ferric oxide, cerium oxide, and samarium oxide, are determined in the ultraviolet and extreme ultraviolet by reflection electron energy loss spectroscopy using primary electron energies in the range 0.3-2.0 ke...

  2. Solid oxide fuel cells fueled with reducible oxides

    Science.gov (United States)

    Chuang, Steven S.; Fan, Liang Shih

    2018-01-09

    A direct-electrochemical-oxidation fuel cell for generating electrical energy includes a cathode provided with an electrochemical-reduction catalyst that promotes formation of oxygen ions from an oxygen-containing source at the cathode, a solid-state reduced metal, a solid-state anode provided with an electrochemical-oxidation catalyst that promotes direct electrochemical oxidation of the solid-state reduced metal in the presence of the oxygen ions to produce electrical energy, and an electrolyte disposed to transmit the oxygen ions from the cathode to the solid-state anode. A method of operating a solid oxide fuel cell includes providing a direct-electrochemical-oxidation fuel cell comprising a solid-state reduced metal, oxidizing the solid-state reduced metal in the presence of oxygen ions through direct-electrochemical-oxidation to obtain a solid-state reducible metal oxide, and reducing the solid-state reducible metal oxide to obtain the solid-state reduced metal.

  3. Surface structural reconstruction of SrVO3 thin films on SrTiO3 (001)

    Science.gov (United States)

    Wang, Gaomin; Saghayezhian, Mohammad; Chen, Lina; Guo, Hangwen; Zhang, Jiandi

    Paramagnetic metallic oxide SrVO3>(SVO) is an itinerant system known to undergo thickness-induced metal-insulator-transition (MIT) in ultrathin film form, which makes it a prototype system for the study of the mechanism behind metal-insulator-transition like structure distortion, electron correlations and disorder-induced localization. We have grown SrVO3 thin film with atomically flat surface through the layer-by-layer deposition by laser Molecular Beam Epitaxy (laser-MBE) on SrTiO3 (001) surface. Low Energy Electron Diffraction (LEED) measurements reveal that there is a (√2X √2) R45°surface reconstruction independent of film thickness. By using LEED-I(V) structure refinement, we determine the surface structure. In combination with X-ray Photoelectron Spectroscopy (XPS) and Scanning Tunneling Microscopy (STM), we discuss the implication on the MIT in ultrathin films below 2-3 unit cell thickness. This work is supported by the National Science Foundation under the NSF EPSCoR Cooperative Agreement No. EPS-1003897 with additional support from the Louisiana Board of Regents.

  4. Comparative Study of Biofuel and Biodiesel Blend with Mineral Diesel Using One-Dimensional Simulation

    International Nuclear Information System (INIS)

    Rahim, Rafidah; Mamat, Rizalman; Taib, Mohd Yusof

    2012-01-01

    This study is intended to perform one-dimensional simulation for four cylinders diesel engine by using various type of fuels and blend. The testing of biofuels properties conducted according to ASTM standards. The physical properties of the fuel are investigated in chemical laboratory which comprises of flash point, kinematic viscosity, density, cloud and pour point, acid value and moisture content. There are three types of fuels used throughout the study, which are straight vegetable oil (SVO), biodiesel 20% blend (B20) and biodiesel 5% blend (B5). Then, the properties data from the experiment will be used in the simulation GT Power software. Simulation tests have been run with the aim of obtaining comparative measures of torque, power, specific fuel consumption and volumetric efficiency. The results is use to evaluate and analyze the performance of diesel engine running with the mentioned fuels above. The comparison performances for each fuel have been discussed. There is no significant difference in the engine performance when fueled with B5 and diesel. There is only about one percent lower of B5 and four percent higher of B20 and SVO compare to diesel fuel.

  5. Social value orientation: theoretical and measurement issues in the study of social preferences.

    Science.gov (United States)

    Murphy, Ryan O; Ackermann, Kurt A

    2014-02-01

    What motivates people when they make decisions and how those motivations are potentially entangled with concerns for others are central topics for the social, cognitive, and behavioral sciences. According to the postulate of narrow self-interest, decision makers have the goal of maximizing personal payoffs and are wholly indifferent to the consequences for others. The postulate of narrow self-interest-which has been influential in economics, psychology, and sociology-is precise and powerful but is often simply wrong. Its inadequacy is well known and efforts have been made to develop reliable and valid measurement methods to quantify the more nuanced social preferences that people really have. In this paper, we report on the emergence and development of the predominant conceptualization of social preferences in psychology: social value orientation (SVO). Second, we discuss the relationship between measurement and theory development of the SVO construct. We then provide an overview of the literature regarding measurement methods that have been used to assess individual variations in social preferences. We conclude with a comparative evaluation of the various measures and provide suggestions regarding the measures' constructive use in building psychologically realistic theories of people's social preferences.

  6. Use of crude filtered vegetable oil as a fuel in diesel engines state of the art: Literature review

    Energy Technology Data Exchange (ETDEWEB)

    Sidibe, S.S.; Azoumah, Y. [Institut Internationale d' ingenierie de l' Eau et de l' Environnement (2iE), rue de science 01 Ouagadougou 01 BP 594 (Burkina Faso); Blin, J. [Institut Internationale d' ingenierie de l' Eau et de l' Environnement (2iE), rue de science 01 Ouagadougou 01 BP 594 (Burkina Faso); Centre International de Recherche Agronomique pour le Developpement (CIRAD), UPR Biomasse energie, TA B-42/16, 73 rue JF Breton, 34398 Montpellier Cedex 5 (France); Vaitilingom, G. [Centre International de Recherche Agronomique pour le Developpement (CIRAD), UPR Biomasse energie, TA B-42/16, 73 rue JF Breton, 34398 Montpellier Cedex 5 (France)

    2010-12-15

    Many studies have been published on vegetable oil use in diesel engines. The different authors unanimously acknowledge the potential and merits of this renewable fuel. Typically, Straight Vegetable Oils (SVOs) produced locally on a small scale, have proven to be easy to produce with very little environmental impact. However, as their physico-chemical characteristics differ from those of diesel oil, their use in diesel engines can lead to a certain number of technical problems over time. In bibliography, there is substantial disagreement between authors regarding the advanced phenomena linked to this problems and the recommended solutions. Some of these publications treat options individually without any real comparison between them. Another observation is that the literature rarely tackles problems linked to vegetable oil quality. This paper sets out to review the state of the art for SVO use as fuel in diesel engines, based on a bibliographic study (literature review). The first section of the document examines the influence of the type and quality of vegetable oils for fuel use in diesel engines. The second section discusses the advantages and disadvantages of two options recommended for SVO use in diesel engines: dual fuelling and blending with diesel fuel. (author)

  7. Negative Transfer Effects on L2 Word Order Processing

    Directory of Open Access Journals (Sweden)

    Kepa Erdocia

    2018-03-01

    Full Text Available Does first language (L1 word order affect the processing of non-canonical but grammatical syntactic structures in second language (L2 comprehension? In the present study, we test whether L1-Spanish speakers of L2-Basque process subject–verb–object (SVO and object–verb–subject (OVS non-canonical word order sentences of Basque in the same way as Basque native speakers. Crucially, while OVS orders are non-canonical in both Spanish and Basque, SVO is non-canonical in Basque but is the canonical word order in Spanish. Our electrophysiological results showed that the characteristics of L1 affect the processing of the L2 even at highly proficient and early-acquired bilingual populations. Specifically, in the non-native group, we observed a left anterior negativity-like component when comparing S and O at sentence initial position and a P600 when comparing those elements at sentence final position. Those results are similar of those reported by Casado et al. (2005 for native speakers of Spanish indicating that L2-Basque speakers rely in their L1-Spanish when processing SVO–OVS word order sentences. Our results favored the competition model (MacWhinney, 1997.

  8. Effects of Oxidation on Oxidation-Resistant Graphite

    Energy Technology Data Exchange (ETDEWEB)

    Windes, William [Idaho National Lab. (INL), Idaho Falls, ID (United States); Smith, Rebecca [Idaho National Lab. (INL), Idaho Falls, ID (United States); Carroll, Mark [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-05-01

    The Advanced Reactor Technology (ART) Graphite Research and Development Program is investigating doped nuclear graphite grades that exhibit oxidation resistance through the formation of protective oxides on the surface of the graphite material. In the unlikely event of an oxygen ingress accident, graphite components within the VHTR core region are anticipated to oxidize so long as the oxygen continues to enter the hot core region and the core temperatures remain above 400°C. For the most serious air-ingress accident which persists over several hours or days the continued oxidation can result in significant structural damage to the core. Reducing the oxidation rate of the graphite core material during any air-ingress accident would mitigate the structural effects and keep the core intact. Previous air oxidation testing of nuclear-grade graphite doped with varying levels of boron-carbide (B4C) at a nominal 739°C was conducted for a limited number of doped specimens demonstrating a dramatic reduction in oxidation rate for the boronated graphite grade. This report summarizes the conclusions from this small scoping study by determining the effects of oxidation on the mechanical strength resulting from oxidation of boronated and unboronated graphite to a 10% mass loss level. While the B4C additive did reduce mechanical strength loss during oxidation, adding B4C dopants to a level of 3.5% or more reduced the as-fabricated compressive strength nearly 50%. This effectively minimized any benefits realized from the protective film formed on the boronated grades. Future work to infuse different graphite grades with silicon- and boron-doped material as a post-machining conditioning step for nuclear components is discussed as a potential solution for these challenges in this report.

  9. Self-assembled manganese oxide structures through direct oxidation

    KAUST Repository

    Zhao, Chao; Wang, Qingxiao; Yang, Yang; Zhang, Bei; Zhang, Xixiang

    2012-01-01

    The morphology and phase of self-assembled manganese oxides during different stages of thermal oxidation were studied. Very interesting morphological patterns of Mn oxide films were observed. At the initial oxidation stage, the surface was characterized by the formation of ring-shaped patterns. As the oxidation proceeded to the intermediate stage, concentric plates formed to relax the compressive stress. Our experimental results gave a clear picture of the evolution of the structures. We also examined the properties of the structures. © 2012 Elsevier B.V.

  10. Self-assembled manganese oxide structures through direct oxidation

    KAUST Repository

    Zhao, Chao

    2012-12-01

    The morphology and phase of self-assembled manganese oxides during different stages of thermal oxidation were studied. Very interesting morphological patterns of Mn oxide films were observed. At the initial oxidation stage, the surface was characterized by the formation of ring-shaped patterns. As the oxidation proceeded to the intermediate stage, concentric plates formed to relax the compressive stress. Our experimental results gave a clear picture of the evolution of the structures. We also examined the properties of the structures. © 2012 Elsevier B.V.

  11. Necropsia e mortalidade por causa mal definida no Estado de São Paulo, Brasil Autopsy and ill-defined cause of death in the state of São Paulo, Brazil

    Directory of Open Access Journals (Sweden)

    Mauro Abrahão Rozman

    2006-11-01

    Full Text Available OBJETIVO: Investigar a proporção de mortes por causa mal definida no Estado de São Paulo entre 1980 e 2002, considerando a influência da realização de necropsia nessa proporção. MÉTODO: O número de óbitos foi obtido do Ministério da Saúde. Dividiu-se o Estado de São Paulo em três áreas: 1 municípios com serviço de verificação de óbitos (SVO, que pode realizar necropsias; 2 municípios sem SVO; e 3 Baixada Santista, região onde houve um aumento marcante na proporção de mortes por causa mal definida entre 1980 e 1995. O impacto das necropsias na proporção de óbitos por causa mal definida foi medido com base na classificação da causa de óbito pelo primeiro médico avaliador (aquele que encaminhou o caso para o SVO para necropsia ou que preencheu a declaração de óbito sem encaminhar o caso. Os óbitos por causas externas foram excluídos por ter necropsia obrigatória. Foram avaliadas as proporções 1 de casos classificados como de causa mal definida pelo primeiro avaliador; 2 de necropsias no total de óbitos excluindo causas externas; e 3 de óbitos com causa esclarecida por necropsia entre os classificados como de causa mal definida pelo primeiro avaliador. RESULTADOS: A proporção de óbitos classificados como de causa mal definida pelo primeiro avaliador aumentou entre 1980 e 2002 em todas as áreas: nos municípios com SVO, nos municípios sem SVO e na Baixada Santista. Para o Estado de São Paulo como um todo, o aumento foi de quase 30% no período de 1980 a 2002. Para o período de 1998 a 2002, a proporção média de necropsias no total de óbitos excluindo causas externas foi de 21,2, 6,4 e 2,6%, respectivamente, nas áreas com e sem SVO e na Baixada Santista. Entre 1998 e 2002, a proporção de óbitos com causa mal definida esclarecidos pela necropsia foi de 92,9 nas áreas com SVO, 32,5 nas áreas sem SVO e 10,7% na Baixada Santista. CONCLUSÕES: A realização de necropsias explica a diferença na

  12. Heterogeneous Partial (ammOxidation and Oxidative Dehydrogenation Catalysis on Mixed Metal Oxides

    Directory of Open Access Journals (Sweden)

    Jacques C. Védrine

    2016-01-01

    Full Text Available This paper presents an overview of heterogeneous partial (ammoxidation and oxidative dehydrogenation (ODH of hydrocarbons. The review has been voluntarily restricted to metal oxide-type catalysts, as the partial oxidation field is very broad and the number of catalysts is quite high. The main factors of solid catalysts for such reactions, designated by Grasselli as the “seven pillars”, and playing a determining role in catalytic properties, are considered to be, namely: isolation of active sites (known to be composed of ensembles of atoms, Me–O bond strength, crystalline structure, redox features, phase cooperation, multi-functionality and the nature of the surface oxygen species. Other important features and physical and chemical properties of solid catalysts, more or less related to the seven pillars, are also emphasized, including reaction sensitivity to metal oxide structure, epitaxial contact between an active phase and a second phase or its support, synergy effect between several phases, acid-base aspects, electron transfer ability, catalyst preparation and activation and reaction atmospheres, etc. Some examples are presented to illustrate the importance of these key factors. They include light alkanes (C1–C4 oxidation, ethane oxidation to ethylene and acetic acid on MoVTe(SbNb-O and Nb doped NiO, propene oxidation to acrolein on BiMoCoFe-O systems, propane (ammoxidation to (acrylonitrile acrylic acid on MoVTe(SbNb-O mixed oxides, butane oxidation to maleic anhydride on VPO: (VO2P2O7-based catalyst, and isobutyric acid ODH to methacrylic acid on Fe hydroxyl phosphates. It is shown that active sites are composed of ensembles of atoms whose size and chemical composition depend on the reactants to be transformed (their chemical and size features and the reaction mechanism, often of Mars and van Krevelen type. An important aspect is the fact that surface composition and surface crystalline structure vary with reaction on stream until

  13. Orientação de valor social, sistema de valores e comportamento cooperativo: um estudo experimental

    Directory of Open Access Journals (Sweden)

    Tatiana Iwai

    2016-02-01

    Full Text Available Objetivo: Este trabalho teve por objetivo compreender a relação entre a orienta- ção de valor social do indivíduo e a teoria dos valores humanos de Schwartz, bem como compreender a relação desses modelos com o comportamento cooperativo do indivíduo sob ambientes regulatórios diferentes (presença e ausência de controle externo. Originalidade/lacuna/relevância/implicações: Apesar de serem dois modelos de destaque em seus respectivos campos, pouco tem sido feito no sentido de achar pontos de convergência entre eles. Assim, esta linha de investigação poderia facilitar não apenas o diálogo entre duas tradições formalmente separadas de pesquisa, mas também melhorar nosso entendimento sobre o efeito de valores e preferências sobre o comportamento cooperativo do indivíduo. Principais aspectos metodológicos: Os dados foram coletados por meio da escala PVQ-21 de Schwartz, os jogos decompostos da SVO Slider e a aplicação de um jogo agente-principal em um ambiente de pesquisa experimental. Síntese dos principais resultados: Os resultados indicam que os tipos sociais da SVO diferem principalmente em seus valores de poder e realização. Ademais, os resultados apontam que a cooperação do pró-social tem como base a motivação intrínseca de igualdade de resultados, sendo menos sensível a controles externos. Diferentemente, o comportamento cooperativo do individualista, calcado em maximização individual, depende mais da existência de restrições externas. Principais considerações/conclusões: Os resultados indicam que os tipos sociais da SVO apresentam diferenças em suas prioridades de valores, e, portanto, o sistema de valores do indivíduo pode ajudar a explicar uma parte da propensão a cooperar do indivíduo.

  14. Testing and preformance measurement of straight vegetable oils as an alternative fuel for diesel engines

    Science.gov (United States)

    Lakshminarayanan, Arunachalam

    Rising fuel prices, growing energy demand, concerns over domestic energy security and global warming from greenhouse gas emissions have triggered the global interest in bio-energy and bio-fuel crop development. Backlash from these concerns can result in supply shocks of traditional fossil fuels and create immense economic pressure. It is thus widely argued that bio-fuels would particularly benefit developing countries by off-setting their dependencies on imported petroleum. Domestically, the transportation sector accounts for almost 40% of liquid fuel consumption, while on-farm application like tractors and combines for agricultural purposes uses close to an additional 18%. It is estimated that 40% of the farm budget can be attributed to the fuel costs. With the cost of diesel continuously rising, farmers are now looking at using Straight Vegetable Oil (SVO) as an alternative fuel by producing their own fuel crops. This study evaluates conventional diesel compared to the use of SVO like Camelina, Canola and Juncea grown on local farms in Colorado for their performance and emissions on a John Deere 4045 Tier-II engine. Additionally, physical properties like density and viscosity, metal/mineral content, and cold flow properties like CFPP and CP of these oils were measured using ASTM standards and compared to diesel. It was found that SVOs did not show significant differences compared to diesel fuel with regards to engine emissions, but did show an increase in thermal efficiency. Therefore, this study supports the continued development of SVO production as a viable alternative to diesel fuels, particularly for on-farm applications. The need for providing and developing a sustainable, economic and environmental friendly fuel alternative has taken an aggressive push which will require a strong multidisciplinary education in the field of bio-energy. Commercial bio-energy development has the potential to not only alleviate the energy concerns, but also to give renewed

  15. Simulation of 3D mesoscale structure formation in concentrated aqueous solution of the triblock polymer surfactants (ethylene oxide)(13)(propylene oxide)(30)(ethylene oxide)(13) and (propylene oxide)(19)(ethylene oxide)(33)(propylene oxide)(19). Application of dynamic mean-field density functional theory

    NARCIS (Netherlands)

    van Vlimmeren, BAC; Maurits, NM; Zvelindovsky, AV; Sevink, GJA; Fraaije, JGEM

    1999-01-01

    We simulate the microphase separation dynamics of aqueous solutions of the triblock polymer surfactants (ethylene oxide)(13)(propylene oxide)(30)(ethylene oxide)(13) and (propylene oxide)(19)(ethylene oxide)(33)(propylene oxide)(19) by a dynamic variant of mean-field density functional theory for

  16. Polyaniline: Aniline oxidation with strong and weak oxidants under various acidity

    Energy Technology Data Exchange (ETDEWEB)

    Bláha, Michal, E-mail: blaha@imc.cas.cz [Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, 162 06 Prague 6 (Czech Republic); Trchová, Miroslava; Bober, Patrycja; Morávková, Zuzana [Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, 162 06 Prague 6 (Czech Republic); Prokeš, Jan [Charles University, Faculty of Mathematics and Physics, 180 00 Prague 8 (Czech Republic); Stejskal, Jaroslav [Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, 162 06 Prague 6 (Czech Republic)

    2017-06-15

    Aniline was oxidized with three strong inorganic oxidants (ammonium peroxydisulfate, cerium(IV) sulfate, potassium dichromate), two weak inorganic oxidants (iron(III) chloride, silver nitrate), and one organic oxidant (p-benzoquinone) in aqueous solutions of methanesulfonic acid (MSA) of various concentration. Whereas oxidation of aniline with ammonium peroxydisulfate yielded high-molecular-weight conducting polyaniline (PANI) in the whole acidity range, the oxidation with cerium(IV) sulfate led also to a single product close to PANI with considerably lower molecular weight and lower conductivity. Potassium dichromate gave PANI only at high concentration of MSA. The use of iron(III) chloride yielded composite mixtures of PANI and low-molecular-weight aniline oligomers. The oxidation of aniline with silver nitrate led to composites of silver and an organic part, which was constituted either by aniline oligomers or conducting polyaniline or both. p-Benzoquinone as oxidant produced mainly aniline oligomers with poor conductivity and 2,5-dianilino-p-benzoquinone-like structure detected in FTIR and Raman spectra when oxidation proceeded with weak oxidants. A general model of oxidation with strong and weak oxidants was formulated. - Highlights: • Comparison of aniline oxidation with oxidants of different redox potential. • UV–vis, FTIR and Raman spectroscopies combined with size-exclusion chromatography. • The contents of polymer and oligomers were analyzed and discussed. • General model of aniline oxidation with strong and weak oxidants was formulated.

  17. Oxidative Decarboxylation of Levulinic Acid by Cupric Oxides

    Directory of Open Access Journals (Sweden)

    Lu Lin

    2010-11-01

    Full Text Available In this paper, cupric oxides was found to effectively oxidize levulinic acid (LA and lead to the decarboxylation of levulinic acid to 2-butanone. The effects of cupric oxide dosage, reaction time and initial pH value were investigated in batch experiments and a plausible mechanism was proposed. The results showed that LA decarboxylation over cupric oxides at around 300 °C under acidic conditions produced the highest yield of butanone (67.5%. In order to elucidate the catalytic activity of cupric oxides, XRD, AFM, XPS and H2-TPR techniques was applied to examine their molecular surfaces and their effects on the reaction process.

  18. Oxide ceramics

    International Nuclear Information System (INIS)

    Ryshkewitch, E.; Richerson, D.W.

    1985-01-01

    The book explores single-phase ceramic oxide systems from the standpoint of physical chemistry and technology. This second edition also focuses on advances in technology since publication of the original edition. These include improvements in raw materials and forming and sintering techniques, and the major role that oxide ceramics have had in development of advanced products and processes. The text is divided into five major sections: general fundamentals of oxide ceramics, advances in aluminum oxide technology, advances in zirconia technology, and advances in beryllium oxide technology

  19. Uranium oxidation: characterization of oxides formed by reaction with water

    International Nuclear Information System (INIS)

    Fuller, E.L. Jr.; Smyrl, N.R.; Condon, J.B.; Eager, M.H.

    1983-01-01

    Three different uranium oxide samples have been characterized with respect to the different preparation techniques. Results show that the water reaction with uranium metal occurs cyclically forming laminar layers of oxide which spall off due to the strain at the oxide/metal interface. Single laminae are released if liquid water is present due to the prizing penetration at the reaction zone. The rate of reaction of water with uranium is directly proportional to the amount of adsorbed water on the oxide product. Rapid transport is effected through the open hydrous oxide product. Dehydration of the hydrous oxide irreversibly forms a more inert oxide which cannot be rehydrated to the degree that prevails in the original hydrous product of uranium oxidation with water. 27 figures

  20. ESR study into mechanism of heterogeneous-catalytic oxidation on oxides

    Energy Technology Data Exchange (ETDEWEB)

    Topchieva, K V; Loginov, A Yu; Kostikov, S V [Moskovskij Gosudarstvennyj Univ. (USSR)

    1977-12-11

    The role of radical particles in heterogeneous-catalytic oxidation of H/sub 2/; CO; SO/sub 2/; NH/sub 3/; C/sub 3/H/sub 6/ on the rare earth oxides (yttrium, lanthanum, magnesium and scandium oxides) and alkaline earth metal oxides was studied by the ESR method. The conclusion was made about the great reactivity of the peroxide structures O/sub 2//sup -/ in the oxidation catalysis in comparison to other formulas of chemisorption oxigen on oxides. The kinetic investigations are chemisorption oxigen on oxides. The kinetic investigations are carried out on the change of the concentration of paramagnetic particles O/sub 2/ during the catalysis. On the basis of the received data the conclusion is made about the reaction process of catalytic oxidation on rare and alkaline-earth oxides according to radical-chain mechanism with the formation of radical particles O/sub 2//sup -/, CO/sub 3//sup -/, SO/sub 4//sup -/, CO/sub 2//sup -/ as interediate products.

  1. Alumina composites for oxide/oxide fibrous monoliths

    International Nuclear Information System (INIS)

    Cruse, T. A.; Polzin, B. J.; Picciolo, J. J.; Singh, D.; Tsaliagos, R. N.; Goretta, K. C.

    2000-01-01

    Most work on ceramic fibrous monoliths (FMs) has focused on the Si 3 N 4 /BN system. In an effort to develop oxidation-resistant FMs, several oxide systems have recently been examined. Zirconia-toughened alumina and alumina/mullite appear to be good candidates for the cell phase of FMs. These composites offer higher strength and toughness than pure alumina and good high-temperature stability. By combining these oxides, possibly with a weaker high-temperature oxide as the cell-boundary phase, it should be possible to product a strong, resilient FM that exhibits graceful failure. Several material combinations have been examined. Results on FM fabrication and microstructural development are presented

  2. Primary circuit water chemistry during shutdown period at Kalinin NPP

    International Nuclear Information System (INIS)

    Gorbatenko, S.; Otchenashev, G.; Yurmanov, V.

    2005-01-01

    The primary circuit water chemistry feature at Kalinin NPP is using of special up-dated regime during the period of unit shutdown for refueling. The main objective of up-dated regime is removing from the circuit long time living corrosion products on SVO-2 ion exchange filters with the purpose of dose rates reduction from the equipment and in such a way reduction of maintenance personnel overexposure. (N.T.)

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

    Science.gov (United States)

    Lu, Peizhen Kathy; Mahapatra, Manoj Kumar

    2013-09-24

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

  4. Oxidized Lipoprotein as a Major Vessel Cell Proliferator in Oxidized Human Serum.

    Directory of Open Access Journals (Sweden)

    Yoshiro Saito

    Full Text Available Oxidative stress is correlated with the incidence of several diseases such as atherosclerosis and cancer, and oxidized biomolecules have been determined as biomarkers of oxidative stress; however, the detailed molecular relationship between generated oxidation products and the promotion of diseases has not been fully elucidated. In the present study, to clarify the role of serum oxidation products in vessel cell proliferation, which is related to the incidence of atherosclerosis and cancer, the major vessel cell proliferator in oxidized human serum was investigated. Oxidized human serum was prepared by free radical exposure, separated using gel chromatography, and then each fraction was added to several kinds of vessel cells including endothelial cells and smooth muscle cells. It was found that a high molecular weight fraction in oxidized human serum specifically induced vessel cell proliferation. Oxidized lipids were contained in this high molecular weight fraction, while cell proliferation activity was not observed in oxidized lipoprotein-deficient serum. Oxidized low-density lipoproteins induced vessel cell proliferation in a concentration-dependent manner. Taken together, these results indicate that oxidized lipoproteins containing lipid oxidation products function as a major vessel cell proliferator in oxidized human serum. These findings strongly indicate the relevance of determination of oxidized lipoproteins and lipid oxidation products in the diagnosis of vessel cell proliferation-related diseases such as atherosclerosis and cancer.

  5. Anaerobic sulfide-oxidation in marine colorless sulfur-oxidizing bacteria

    Digital Repository Service at National Institute of Oceanography (India)

    LokaBharathi, P.A.; Nair, S.; Chandramohan, D.

    Colorless sulfur-oxidizing bacteria are ubiquitous in Indian waters and have the ability to oxidize sulfide under anaerobic conditions. These bacteria can not only mediate the sulfur cycle oxidatively but also the nitrogen cycle reductively without...

  6. Interactions between iron oxides and copper oxides under hydrothermal conditions

    Energy Technology Data Exchange (ETDEWEB)

    McGarvey, G B; Owen, D G

    1995-08-01

    Under hydrothermal conditions, magnetite and hematite have been shown to undergo interconversion reactions, the extent of which is controlled in part by the presence of copper oxides. In oxygenated water, the degree to which magnetite was oxidized to hematite was found to be dependent on the presence of CuO or Cu{sub 2}O. When these materials were absent, the oxidation of magnetite was limited by the dissolved oxygen in the aqueous system. Participation of the copper oxides in the oxidation process was confirmed by more complete conversion of magnetite was also influenced by the presence of the copper oxides. In addition to driving the reduction to completion, the presence of the copper oxides also exerted a strong influence over the morphology of the magnetite that formed. (author). 13 refs., 1 tab., 3 figs.

  7. Radiation-induced cationic polymerization of limonene oxide, α-pinene oxide, and β-pinene oxide

    International Nuclear Information System (INIS)

    Aikins, J.A.; Williams, F.

    1984-01-01

    After suitable drying, the subject monomers in the form of neat liquids undergo radiation-induced polymerization with no apparent side reactions and high conversions to precipitatable polymers of low molecular weight. A cationic mechanism is evidenced by the strongly retarding effect of tri-n-propylamine on the polymerization rate. At 25 0 C, limonene oxide gives the highest polymerization rates, an average conversion of 36% per Mrad being obtained in comparison with values of 5.7 and 7.3% per Mrad for the α-pinene and β-pinene oxides, respectively. Similarly, the average anti DP/sub n/ decreases from 11.8 for the limonene oxide polymer to 5.6 and 4.0 for the α-pinene oxide and β-pinene oxide polymers, respectively. A high frequency of chain transfer to monomer is indicated in each case by the fact that the kinetic chain lengths are estimated to be on the order of a hundred times larger than the anti DP/sub n/ values. Structural characterization of the limonene oxide polymer by 1 H and 13 C NMR spectroscopy provides conclusive evidence that the polymerization proceeds by the opening of the epoxide ring to yield a 1,2-trans polyether. Similar NMR studies on the polymers formed from the α-pinene and β-pinene oxides show that in the polymerization of these monomers, the opening of the epoxide ring is generally accompanied by the concomitant ring opening of the cyclobutane ring structure to yield a gem-dimethyl group in the main chain. The detection of isopropenyl end groups in the pinene oxide polymers is also consistent with this mode of propagation being followed by chain (proton) transfer to monomer

  8. Nanostructured manganese oxide/carbon nanotubes, graphene and graphene oxide as water-oxidizing composites in artificial photosynthesis.

    Science.gov (United States)

    Najafpour, Mohammad Mahdi; Rahimi, Fahime; Fathollahzadeh, Maryam; Haghighi, Behzad; Hołyńska, Małgorzata; Tomo, Tatsuya; Allakhverdiev, Suleyman I

    2014-07-28

    Herein, we report on nano-sized Mn oxide/carbon nanotubes, graphene and graphene oxide as water-oxidizing compounds in artificial photosynthesis. The composites are synthesized by different and simple procedures and characterized by a number of methods. The water-oxidizing activities of these composites are also considered in the presence of cerium(IV) ammonium nitrate. Some composites are efficient Mn-based catalysts with TOF (mmol O2 per mol Mn per second) ~ 2.6.

  9. Oxidation of methyl heterocyclic compounds on vanadium oxide catalysts

    International Nuclear Information System (INIS)

    Shimanskaya, M.V.; Lejtis, L.A.; Iovel', I.G.; Gol'dberg, Yu.Sh.; Skolmejstere, R.A.; Golender, L.O.

    1985-01-01

    Data on vapor-phase oxidation of methyl derivatives of thiophene, Δ 2 - thiazo line, pyridine, pyrazine and pyramidine on oxide vanadium-molybdenum catalysts to corresponding heterylaldehydes are generalized. The dependence of catalytic properties of oxide vanadium-molybdenum systems in oxidation reactions of methylheterocyclic compounds on V:Mo ratio in the catalyst is revealed. It is shown that heterocyclic compounds are coordinated by a heteroatom on Lewis centres of V-Mo-O-catalyst primarily with partially reduced vanadium ions

  10. MDMA enhances emotional empathy and prosocial behavior

    Science.gov (United States)

    Hysek, Cédric M.; Schmid, Yasmin; Simmler, Linda D.; Domes, Gregor; Heinrichs, Markus; Eisenegger, Christoph; Preller, Katrin H.; Quednow, Boris B.

    2014-01-01

    3,4-Methylenedioxymethamphetamine (MDMA, ‘ecstasy’) releases serotonin and norepinephrine. MDMA is reported to produce empathogenic and prosocial feelings. It is unknown whether MDMA in fact alters empathic concern and prosocial behavior. We investigated the acute effects of MDMA using the Multifaceted Empathy Test (MET), dynamic Face Emotion Recognition Task (FERT) and Social Value Orientation (SVO) test. We also assessed effects of MDMA on plasma levels of hormones involved in social behavior using a placebo-controlled, double-blind, random-order, cross-over design in 32 healthy volunteers (16 women). MDMA enhanced explicit and implicit emotional empathy in the MET and increased prosocial behavior in the SVO test in men. MDMA did not alter cognitive empathy in the MET but impaired the identification of negative emotions, including fearful, angry and sad faces, in the FERT, particularly in women. MDMA increased plasma levels of cortisol and prolactin, which are markers of serotonergic and noradrenergic activity, and of oxytocin, which has been associated with prosocial behavior. In summary, MDMA sex-specifically altered the recognition of emotions, emotional empathy and prosociality. These effects likely enhance sociability when MDMA is used recreationally and may be useful when MDMA is administered in conjunction with psychotherapy in patients with social dysfunction or post-traumatic stress disorder. PMID:24097374

  11. LSD Acutely Impairs Fear Recognition and Enhances Emotional Empathy and Sociality.

    Science.gov (United States)

    Dolder, Patrick C; Schmid, Yasmin; Müller, Felix; Borgwardt, Stefan; Liechti, Matthias E

    2016-10-01

    Lysergic acid diethylamide (LSD) is used recreationally and has been evaluated as an adjunct to psychotherapy to treat anxiety in patients with life-threatening illness. LSD is well-known to induce perceptual alterations, but unknown is whether LSD alters emotional processing in ways that can support psychotherapy. We investigated the acute effects of LSD on emotional processing using the Face Emotion Recognition Task (FERT) and Multifaceted Empathy Test (MET). The effects of LSD on social behavior were tested using the Social Value Orientation (SVO) test. Two similar placebo-controlled, double-blind, random-order, crossover studies were conducted using 100 μg LSD in 24 subjects and 200 μg LSD in 16 subjects. All of the subjects were healthy and mostly hallucinogen-naive 25- to 65-year-old volunteers (20 men, 20 women). LSD produced feelings of happiness, trust, closeness to others, enhanced explicit and implicit emotional empathy on the MET, and impaired the recognition of sad and fearful faces on the FERT. LSD enhanced the participants' desire to be with other people and increased their prosocial behavior on the SVO test. These effects of LSD on emotion processing and sociality may be useful for LSD-assisted psychotherapy.

  12. Selective carbon monoxide oxidation over Ag-based composite oxides

    Energy Technology Data Exchange (ETDEWEB)

    Guldur, C. [Gazi University, Ankara (Turkey). Chemical Engineering Department; Balikci, F. [Gazi University, Ankara (Turkey). Institute of Science and Technology, Environmental Science Department

    2002-02-01

    We report our results of the synthesis of 1 : 1 molar ratio of the silver cobalt and silver manganese composite oxide catalysts to remove carbon monoxide from hydrogen-rich fuels by the catalytic oxidation reaction. Catalysts were synthesized by the co-precipitation method. XRD, BET, TGA, catalytic activity and catalyst deactivation studies were used to identify active catalysts. Both CO oxidation and selective CO oxidation were carried out in a microreactor using a reaction gas mixture of 1 vol% CO in air and another gas mixture was prepared by mixing 1 vol% CO, 2 vol% O{sub 2}, 84 vol% H{sub 2}, the balance being He. 15 vol% CO{sub 2} was added to the reactant gas mixture in order to determine the effect of CO{sub 2}, reaction gases were passed through the humidifier to determine the effect of the water vapor on the oxidation reaction. It was demonstrated that metal oxide base was decomposed to the metallic phase and surface areas of the catalysts were decreased when the calcination temperature increased from 200{sup o}C to 500{sup o}C. Ag/Co composite oxide catalyst calcined at 200{sup o}C gave good activity at low temperatures and 90% of CO conversion at 180{sup o}C was obtained for the selective CO oxidation reaction. The addition of the impurities (CO{sub 2} or H{sub 2}O) decreased the activity of catalyst for selective CO oxidation in order to get highly rich hydrogen fuels. (author)

  13. Oxidized limonene and oxidized linalool - concomitant contact allergy to common fragrance terpenes.

    Science.gov (United States)

    Bråred Christensson, Johanna; Karlberg, Ann-Therese; Andersen, Klaus E; Bruze, Magnus; Johansen, Jeanne D; Garcia-Bravo, Begoña; Giménez Arnau, Ana; Goh, Chee-Leok; Nixon, Rosemary; White, Ian R

    2016-05-01

    Limonene and linalool are common fragrance terpenes. Both oxidized R-limonene and oxidized linalool have recently been patch tested in an international setting, showing contact allergy in 5.2% and 6.9% of dermatitis patients, respectively. To investigate concomitant reactions between oxidized R-limonene and oxidized linalool in consecutive dermatitis patients. Oxidized R-limonene 3.0% (containing limonene hydroperoxides 0.33%) and oxidized linalool 6% (linalool hydroperoxides 1%) in petrolatum were tested in 2900 consecutive dermatitis patients in Australia, Denmark, Singapore, Spain, Sweden, and the United Kingdom. A total of 281 patients reacted to either oxidized R-limonene or oxidized linalool. Of these, 25% had concomitant reactions to both compounds, whereas 29% reacted only to oxidized R-limonene and 46% only to oxidized linalool. Of the 152 patients reacting to oxidized R-limonene, 46% reacted to oxidized linalool, whereas 35% of the 200 patients reacting to oxidized linalool also reacted to oxidized R-limonene. The majority of the patients (75%) reacted to only one of the oxidation mixtures, thus supporting the specificity of the reactions. The concomitant reactions to the two fragrance allergens suggest multiple sensitizations, which most likely reflect the exposure to the different fragrance materials in various types of consumer products. This is in accordance with what is generally seen for patch test reactions to fragrance materials. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  14. Study of nitric oxide catalytic oxidation on manganese oxides-loaded activated carbon at low temperature

    Energy Technology Data Exchange (ETDEWEB)

    You, Fu-Tian [Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen (China); University of Chinese Academy of Sciences, Beijing (China); Yu, Guang-Wei, E-mail: gwyu@iue.ac.cn [Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen (China); Wang, Yin, E-mail: yinwang@iue.ac.cn [Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen (China); Xing, Zhen-Jiao [Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen (China); Liu, Xue-Jiao; Li, Jie [Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen (China); University of Chinese Academy of Sciences, Beijing (China)

    2017-08-15

    Highlights: • Loading manganese oxides on activated carbon effectively promotes NO oxidation. • NO adsorption-desorption on activated carbon is fundamental to NO oxidation. • A high Mn{sup 4+}/Mn{sup 3+} ratio contributes to NO oxidation by promoting lattice O transfer. - Abstract: Nitric oxide (NO) is an air pollutant that is difficult to remove at low concentration and low temperature. Manganese oxides (MnO{sub x})-loaded activated carbon (MLAC) was prepared by a co-precipitation method and studied as a new catalyst for NO oxidation at low temperature. Characterization of MLAC included X-ray diffraction (XRD), scanning electron microscopy (SEM), N{sub 2} adsorption/desorption and X-ray photoelectron spectroscopy (XPS). Activity tests demonstrated the influence of the amount of MnO{sub x} and the test conditions on the reaction. MLAC with 7.5 wt.% MnO{sub x} (MLAC003) exhibits the highest NO conversion (38.7%) at 1000 ppm NO, 20 vol.% O{sub 2}, room temperature and GHSV ca. 16000 h{sup −1}. The NO conversion of MLAC003 was elevated by 26% compared with that of activated carbon. The results of the MLAC003 activity test under different test conditions demonstrated that NO conversion is also influenced by inlet NO concentration, inlet O{sub 2} concentration, reaction temperature and GHSV. The NO adsorption-desorption process in micropores of activated carbon is fundamental to NO oxidation, which can be controlled by pore structure and reaction temperature. The activity elevation caused by MnO{sub x} loading is assumed to be related to Mn{sup 4+}/Mn{sup 3+} ratio. Finally, a mechanism of NO catalytic oxidation on MLAC based on NO adsorption-desorption and MnO{sub x} lattice O transfer is proposed.

  15. Poly[(ethylene oxide)-co-(methylene ethylene oxide)]: A hydrolytically-degradable poly(ethylene oxide) platform

    OpenAIRE

    Lundberg, Pontus; Lee, Bongjae F.; van den Berg, Sebastiaan A.; Pressly, Eric D.; Lee, Annabelle; Hawker, Craig J.; Lynd, Nathaniel A.

    2012-01-01

    A facile method for imparting hydrolytic degradability to poly(ethylene oxide) (PEO), compatible with current PEGylation strategies, is presented. By incorporating methylene ethylene oxide (MEO) units into the parent PEO backbone, complete degradation was defined by the molar incorporation of MEO, and the structure of the degradation byproducts was consistent with an acid-catalyzed vinyl-ether hydrolysis mechanism. The hydrolytic degradation of poly[(ethylene oxide)-co-(methylene ethylene oxi...

  16. Oxidation films morphology

    International Nuclear Information System (INIS)

    Paidassi, J.

    1960-01-01

    After studying the oxidation of several pure polyvalent metals (Fe, Cu, Mn, Ni, U) and of their oxides at high temperature and atmospheric pressure, the author suggests how to modify the usual representation of the oxide film (a piling of different oxide layers, homogeneous on a micrographic scale with a equi-axial crystallisation, free of mechanical tensions, with flat boundary surfaces) to have it nearer to reality. In this first part, the author exposes the study of the real micrographic structure of the oxidation film and gives examples of precipitation in the oxides during the cooling of the oxidised sample. (author) [fr

  17. New insight of high temperature oxidation on self-exfoliation capability of graphene oxide

    Science.gov (United States)

    Liu, Yuhang; Zeng, Jie; Han, Di; Wu, Kai; Yu, Bowen; Chai, Songgang; Chen, Feng; Fu, Qiang

    2018-05-01

    The preparation of graphene oxide (GO) via Hummers method is usually divided into two steps: low temperature oxidation at 35 °C (step I oxidation) and high temperature oxidation at 98 °C (step II oxidation). However, the effects of these two steps on the exfoliation capability and chemical structure of graphite oxide remain unclear. In this study, both the functional group content of graphite oxide and the entire evolution of interlayer spacing were investigated during the two steps. Step I oxidation is a slowly inhomogeneous oxidation step to remove unoxidized graphite flakes. The prepared graphite oxide can be easily self-exfoliated but contains a lot of organic sulfur. During the first 20 min of step II oxidation, the majority of organic sulfur can be efficiently removed and graphite oxide still remains a good exfoliation capability due to sharp increasing of carboxyl groups. However, with a longer oxidation time at step II oxidation, the decrease of organic sulfur content is slowed down apparently but without any carboxyl groups forming, then graphite oxide finally loses self-exfoliation capability. It is concluded that a short time of step II oxidation can produce purer and ultralarge GO sheets via self-exfoliation. The pure GO is possessed with better thermal stability and liquid crystal behavior. Besides, reduced GO films prepared from step II oxidation show better mechanical and electric properties after reducing compared with that obtained only via step I oxidation.

  18. Poly[(ethylene oxide)-co-(methylene ethylene oxide)]: A hydrolytically-degradable poly(ethylene oxide) platform.

    Science.gov (United States)

    Lundberg, Pontus; Lee, Bongjae F; van den Berg, Sebastiaan A; Pressly, Eric D; Lee, Annabelle; Hawker, Craig J; Lynd, Nathaniel A

    2012-11-20

    A facile method for imparting hydrolytic degradability to poly(ethylene oxide) (PEO), compatible with current PEGylation strategies, is presented. By incorporating methylene ethylene oxide (MEO) units into the parent PEO backbone, complete degradation was defined by the molar incorporation of MEO, and the structure of the degradation byproducts was consistent with an acid-catalyzed vinyl-ether hydrolysis mechanism. The hydrolytic degradation of poly[(ethylene oxide)-co-(methylene ethylene oxide)] was pH-sensitive, with degradation at pH 5 being significantly faster than at pH 7.4 at 37 °C in PBS buffer while long-term stability could be obtained in either the solid-state or at pH 7.4 at 6 °C.

  19. Tungsten oxide nanowires grown on graphene oxide sheets as high-performance electrochromic material

    International Nuclear Information System (INIS)

    Chang, Xueting; Sun, Shibin; Dong, Lihua; Hu, Xiong; Yin, Yansheng

    2014-01-01

    Graphical abstract: Electrochromic mechanism of tungsten oxide nanowires-reduced graphene oxide composite. - Highlights: • A novel inorganic-nano-carbon hybrid composite was prepared. • The hybrid composite has sandwich-like structure. • The hybrid composite exhibited high-quality electrohcromic performance. - Abstract: In this work, we report the synthesis of a novel hybrid electrochromic composite through nucleation and growth of ultrathin tungsten oxide nanowires on graphene oxide sheets using a facile solvothermal route. The competition between the growth of tungsten oxide nanowires and the reduction of graphene oxide sheets leads to the formation of sandwich-structured tungsten oxide-reduced graphene oxide composite. Due to the strongly coupled effect between the ultrathin tungsten oxide nanowires and the reduced graphene oxide nanosheets, the novel electrochromic composite exhibited high-quality electrochromic performance with fast color-switching speed, good cyclic stability, and high coloration efficiency. The present tungsten oxide-reduced graphene oxide composite represents a new approach to prepare other inorganic-reduced graphene oxide hybrid materials for electrochemical applications

  20. Experimental investigation and thermodynamic simulation of the uranium oxide-zirconium oxide-iron oxide system in air

    Czech Academy of Sciences Publication Activity Database

    Petrov, Y. B.; Udalov, Y. P.; Šubrt, Jan; Bakardjieva, Snejana; Sázavský, P.; Kiselová, M.; Selucký, P.; Bezdička, Petr; Joumeau, C.; Piluso, P.

    2011-01-01

    Roč. 37, č. 2 (2011), s. 212-229 ISSN 1087-6596 Institutional research plan: CEZ:AV0Z40320502 Keywords : uranium oxide * zirconium oxide * iron oxide * fusibility curve * oxygen partial pressure * crystallization * phase composition Subject RIV: CA - Inorganic Chemistry Impact factor: 0.492, year: 2011

  1. It has been suggested that oxidative stress, especially oxidative ...

    African Journals Online (AJOL)

    nabipour

    2012-02-14

    Feb 14, 2012 ... 1Department of Clinical Biochemistry, Faculty of Medicine, Bushehr University of Medical Sciences, Bushehr, Iran. 2Department of Cardiology ... oxidative modification of low-density lipoproteins (LDL), may play a causative role in ... the oxidation of lipids in the cell membrane especially the oxidation of LDL.

  2. X-ray Absorption Study of Graphene Oxide and Transition Metal Oxide Nanocomposites.

    Science.gov (United States)

    Gandhiraman, Ram P; Nordlund, Dennis; Javier, Cristina; Koehne, Jessica E; Chen, Bin; Meyyappan, M

    2014-08-14

    The surface properties of the electrode materials play a crucial role in determining the performance and efficiency of energy storage devices. Graphene oxide and nanostructures of 3d transition metal oxides were synthesized for construction of electrodes in supercapacitors, and the electronic structure and oxidation states were probed using near-edge X-ray absorption fine structure. Understanding the chemistry of graphene oxide would provide valuable insight into its reactivity and properties as the graphene oxide transformation to reduced-graphene oxide is a key step in the synthesis of the electrode materials. Polarized behavior of the synchrotron X-rays and the angular dependency of the near-edge X-ray absorption fine structures (NEXAFS) have been utilized to study the orientation of the σ and π bonds of the graphene oxide and graphene oxide-metal oxide nanocomposites. The core-level transitions of individual metal oxides and that of the graphene oxide nanocomposite showed that the interaction of graphene oxide with the metal oxide nanostructures has not altered the electronic structure of either of them. As the restoration of the π network is important for good electrical conductivity, the C K edge NEXAFS spectra of reduced graphene oxide nanocomposites confirms the same through increased intensity of the sp 2 -derived unoccupied states π* band. A pronounced angular dependency of the reduced sample and the formation of excitonic peaks confirmed the formation of extended conjugated network.

  3. Simultaneous removal of nitrogen oxides and sulfur oxides from combustion gases

    Science.gov (United States)

    Clay, David T.; Lynn, Scott

    1976-10-19

    A process for the simultaneous removal of sulfur oxides and nitrogen oxides from power plant stack gases comprising contacting the stack gases with a supported iron oxide catalyst/absorbent in the presence of sufficient reducing agent selected from the group consisting of carbon monoxide, hydrogen, and mixtures thereof, to provide a net reducing atmosphere in the SO.sub.x /NO.sub.x removal zone. The sulfur oxides are removed by absorption substantially as iron sulfide, and nitrogen oxides are removed by catalytic reduction to nitrogen and ammonia. The spent iron oxide catalyst/absorbent is regenerated by oxidation and is recycled to the contacting zone. Sulfur dioxide is also produced during regeneration and can be utilized in the production of sulfuric acid and/or sulfur.

  4. USSR Report, Chemistry.

    Science.gov (United States)

    1987-04-20

    same photoelectric and photoluminescent properties as that obtained by prolonged secondary sintering or remelting Zn in ZnS single crystals. Some...data supported the formation of 5V0«Ho20g in the binary system. SVO’Efc^Oo represents an orthorhombic perovskite -type crystal with a ~ 5.267 A, b0...fiberglasses, carbon fibers—carbonplastics, and their hybrids . They possess different qualities and superior properties. But I must confess that the

  5. Oxidation kinetics of (B6O) boron oxide

    International Nuclear Information System (INIS)

    Makarov, V.S.; Solov'ev, N.E.; Ugaj, Ya.A.

    1987-01-01

    Reactivity of B 6 O to oxygen is investigated. It is shown that the process of B 6 O oxidation in the air in the temperature range 760-1150 K results in the maximum transformation degree equal to 0.35. At the initial stages oxidation proceeds in kinetic regime, at final stages - in diffusion one, and high viscosity of B 2 O 3 probably affects the oxidation process

  6. Chronic exposure to iron oxide, chromium oxide, and nickel oxide fumes of metal dressers in a steelworks

    Science.gov (United States)

    Jones, J. Graham; Warner, C. G.

    1972-01-01

    Graham Jones, J., and Warner, C. G. (1972).Brit. J. industr. Med.,29, 169-177. Chronic exposure to iron oxide, chromium oxide, and nickel oxide fumes of metal dressers in a steelworks. Occupational and medical histories, smoking habits, respiratory symptoms, chest radiographs, and ventilatory capacities were studied in 14 steelworkers employed as deseamers of steel ingots for periods of up to 16 years. The men were exposed for approximately five hours of each working shift to fume concentrations ranging from 1·3 to 294·1 mg/m3 made up mainly of iron oxide with varying proportions of chromium oxide and nickel oxide. Four of the men, with 14 to 16 years' exposure, showed radiological evidence of pneumoconiosis classified as ILO categories 2 or 3. Of these, two had pulmonary function within the normal range and two had measurable loss of function, moderate in one case and mild in the other. Many observers would diagnose these cases as siderosis but the authors consider that this term should be reserved for cases exposed to pure iron compounds. The correct diagnosis is mixed-dust pneumoconiosis and the loss of pulmonary function is caused by the effects of the mixture of metallic oxides. It is probable that inhalation of pure iron oxide does not cause fibrotic pulmonary changes, whereas the inhalation of iron oxide plus certain other substances obviously does. Images PMID:5021996

  7. The 2016 oxide electronic materials and oxide interfaces roadmap

    DEFF Research Database (Denmark)

    Lorenz, M.; Rao, M. S. Ramachandra; Venkatesan, T.

    2016-01-01

    of these materials to understand the tunability of their properties and the novel properties that evolve due to their nanostructured nature is another facet of the challenge. The research related to the oxide electronic field is at an impressionable stage, and this has motivated us to contribute with a roadmap......, Pentcheva, and Gegenwart. Finally, Miletto Granozio presents the European action ‘towards oxide-based electronics’ which develops an oxide electronics roadmap with emphasis on future nonvolatile memories and the required technologies.In summary, we do hope that this oxide roadmap appears as an interesting...

  8. Imprinted Oxide and MIP/Oxide Hybrid Nanomaterials for Chemical Sensors †.

    Science.gov (United States)

    Afzal, Adeel; Dickert, Franz L

    2018-04-20

    The oxides of transition, post-transition and rare-earth metals have a long history of robust and fast responsive recognition elements for electronic, optical, and gravimetric devices. A wide range of applications successfully utilized pristine or doped metal oxides and polymer-oxide hybrids as nanostructured recognition elements for the detection of biologically relevant molecules, harmful organic substances, and drugs as well as for the investigative process control applications. An overview of the selected recognition applications of molecularly imprinted sol-gel phases, metal oxides and hybrid nanomaterials composed of molecularly imprinted polymers (MIP) and metal oxides is presented herein. The formation and fabrication processes for imprinted sol-gel layers, metal oxides, MIP-coated oxide nanoparticles and other MIP/oxide nanohybrids are discussed along with their applications in monitoring bioorganic analytes and processes. The sensor characteristics such as dynamic detection range and limit of detection are compared as the performance criterion and the miniaturization and commercialization possibilities are critically discussed.

  9. Improved Understanding of In Situ Chemical Oxidation Contaminant Oxidation Kinetics

    Science.gov (United States)

    2007-12-01

    natural oxidant demand •OH hydroxide radical Ox oxidant O3 ozone PCE perchloroethylene HSO5− peroxymonosulfate PNDA p...properties (e.g., soil mineralogy , natural carbon content) affect oxidant mobility and stability in the subsurface, and develop a standardized natural...chlorinated ethenes For contaminant oxidation by activated S2O82−, it is more difficult to develop a general description of kobs vs. T because there are

  10. Characterization of tin oxide nanoparticles synthesized via oxidation from metal

    International Nuclear Information System (INIS)

    Abruzzi, R.C.; Dedavid, B.A.; Pires, M.J.R.; Streicher, M.

    2014-01-01

    The tin oxide (SnO_2) is a promising material with great potential for applications such as gas sensors and catalysts. This oxide nanostructures show higher activation efficiency due to its larger effective surface. This paper presents the synthesis and characterization of the tin oxide in different conditions, via oxidation of pure tin with nitric acid. Results obtained from the characterization of SnO_2 powder by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDX), Particle size by Dynamic Light Scattering (DLS) and Infrared Spectroscopy (FTIR) indicated that the conditions were suitable for the synthesis to obtain manometric tin oxide granules with crystalline structure of rutile. (author)

  11. The oxidation; Okislenie

    Energy Technology Data Exchange (ETDEWEB)

    Nikitin, V I

    1961-07-01

    In this chapter of book author determine that alkylene tetra hydro-{gamma}-piron, oxidated by potassium permanganate in all cases of passed oxidation gave oxidation products, confirmatory their structure.

  12. Selectivity in the oxidative dehydrogenation of butene on zinc-iron oxide catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Kung, H.H.; Kundalkar, B.; Kung, M.C.; Cheng, W.H.

    1980-02-21

    Adsorption, temperature-programed desorption, and pulse reaction studies of cis-2-butene and butadiene on spinel zinc ferrite by previously described methods provided evidence that the selectivity for oxidative dehydrogenation of butenes increases when zinc is added to the iron oxide catalyst because selective oxidation and complete oxidation proceed on separate sites, as they do on pure iron; because the density of sites for selective oxidation is higher and the density of sites for complete combustion is lower than on pure iron oxide; and because the activity of the combustion sites is lower.

  13. Direct Coal Oxidation in Modified Solid Oxide Fuel Cells

    DEFF Research Database (Denmark)

    Deleebeeck, Lisa; Gil, Vanesa; Ippolito, Davide

    2017-01-01

    Hybrid direct carbon fuel cells employ a classical solid oxide fuel cell together with carbon dispersed in a carbonate melt on the anode side. In a European project, the utilization of various coals has been investigated with and without addition of an oxidation catalyst to the carbon-carbonate s......Hybrid direct carbon fuel cells employ a classical solid oxide fuel cell together with carbon dispersed in a carbonate melt on the anode side. In a European project, the utilization of various coals has been investigated with and without addition of an oxidation catalyst to the carbon......-carbonate slurry or anode layer. The nature of the coal affects both open circuit voltage and power output. Highest OCV and power densities were observed for bituminous coal and by adding manganese oxide or praseodymium-doped ceria to the carbon/carbonate mixture. Comparing the carbon black fueled performance...... bituminous coal (73 mW/cm2)....

  14. Mechanism of 1, 1-d2 propene oxidation over oxide catalysts

    International Nuclear Information System (INIS)

    Portefaix, J.L.; Figueras, F.; Forissier, M.

    1980-01-01

    CD 2 CHCH 3 was oxidized over bismuth molybdate, tin-antimony mixed oxides and supported molybdenum and vanadium oxide catalysts. The deuterium retention is high ( > 90%) in the recovered propene. Percentage retentions of deuterium in the acrolein agree with literature data when bismuth molybdate is used as catalyst. On Sb-Sn-O and supported Mo and V oxides, no isotope effect is noticed for the abstraction of the second hydrogen from the olefin. The slow step of the reaction may therefore be different for the oxidation of propene on Bi-Mo-O and Sb-Sn-O. The ethanal produced by oxidation of CD 2 CHCH 3 contains only minor amounts of deuterium, whatever the catalyst used. It is suggested that partial oxidation of propene to acrolein and C-C bond rupture are parallel reactions which involve different intermediates. Possible mechanisms adapted from organic chemistry are presented to explain these findings. 4 tables

  15. Oxidation phase growth diagram of vanadium oxides film fabricated by rapid thermal annealing

    Institute of Scientific and Technical Information of China (English)

    Tamura KOZO; Zheng-cao LI; Yu-quan WANG; Jie NI; Yin HU; Zheng-jun ZHANG

    2009-01-01

    Thermal evaporation deposited vanadium oxide films were annealed in air by rapid thermal annealing (RTP). By adjusting the annealing temperature and time, a series of vanadium oxide films with various oxidation phases and surface morphologies were fabricated, and an oxidation phase growth diagram was established. It was observed that different oxidation phases appear at a limited and continuous annealing condition range, and the morphologic changes are related to the oxidation process.

  16. Oxidation of urate by a therapeutic nitric oxide/air mixture

    International Nuclear Information System (INIS)

    Hicks, M.; Nguyen, L.; Day, R.; Rogers, P.

    1996-01-01

    Full text: Little is known about the potential toxicological consequences of therapeutic exposure of lung tissue to inhaled nitric oxide (NO). This route of administration is currently being successfully employed for the treatment of pulmonary hypertension and other lung pathologies including acute reperfusion injury in lung transplant patients. The toxicity of NO lies in its ability to act as an oxidant either in its own right or in concert with oxygen or with the superoxide free radical. One important interaction may be the reaction of these products with protective antioxidants in the lung epithelial lining fluid. One such antioxidant found in significant concentrations in both upper and lower airways is uric acid. In the present study, urate solutions (30μM) were exposed to a therapeutic concentration of NO gas, (35 ppm in air), for up to 90 minutes. Oxidative changes were followed spectrophotometrically and by HPLC. Significant loss of uric acid was observed with a concomitant formation of nitrite and allantoin, the stable oxidation product of NO and the major oxidation product of uric acid, respectively. No oxidation of urate was observed in the presence of air alone or when urate was incubated with nitrite. Uric acid oxidation could also be prevented by passing the NO / air stream through 10% KOH before the uric acid solution. This strategy removed trace amounts of higher oxides of nitrogen, (especially NO 2 ), from the NO / air stream. Thus, therapeutic inhalation of NO may deplete soluble antioxidants such as uric acid, especially during long-term chronic exposure unless care is taken to minimise formation of higher oxides of nitrogen

  17. Effect of the Lithium Oxide Concentration on a Reduction of Lanthanide Oxides

    International Nuclear Information System (INIS)

    Choi, In-Kyu; Jeong, Myeong-Soo; Do, Jae-Bum; Seo, Chung-Seok

    2007-01-01

    The pyrochemical reduction process of spent oxide fuel is one of the options to handle spent PWR fuels in Korea. After spent oxide fuel is converted to a metallic form, fission products will be removed from the resultant uranium and higher actinide metals by an electrorefining process. The chemical behaviors of lanthanide oxides during the pyrochemical process has been extensively studied. It was also reported that about 30 to 50% of several lanthanide oxides were reduced to corresponding metals by an electrolytic reduction process having 1 wt% of a lithium oxide concentration. Korea Atomic Energy Research Institute (KAERI), however, has been used 3 wt% of lithium oxide to increase the applied current of the electrolytic reduction process. Though it was reported that U 3 O 8 was reduced to uranium metal having a high reduction yield at 3 wt% of the Li 2 O concentration, the effect of the lithium oxide concentration on the reduction of lanthanide oxides has not been clarified

  18. Hydrogen sulfide oxidation without oxygen - oxidation products and pathways

    International Nuclear Information System (INIS)

    Fossing, H.

    1992-01-01

    Hydrogen sulfide oxidation was studied in anoxic marine sediments-both in undisturbed sediment cores and in sediment slurries. The turn over of hydrogen sulfide was followed using 35 S-radiolabeled hydrogen sulfide which was injected into the sediment. However, isotope exchange reactions between the reduced sulfur compounds, in particular between elemental sulfur and hydrogen sulfide, influenced on the specific radioactivity of these pools. It was, therefore, not possible to measure the turn over rates of the reduced sulfur pools by the radiotracer technique but merely to use the radioisotope to demonstrate some of the oxidation products. Thiosulfate was one important intermediate in the anoxic oxidation of hydrogen sulfide and was continuously turned over by reduction, oxidation and disproportionation. The author discusses the importance of isotope exchange and also presents the results from experiments in which both 35 S-radiolabeled elemental sulfur, radiolabeled hydrogen sulfide and radiolabeled thiosulfate were used to study the intermediates in the oxidative pathways of the sulfur cycle

  19. Direct Coal Oxidation in Modified Solid Oxide Fuel Cells

    DEFF Research Database (Denmark)

    Deleebeeck, Lisa; Gil, Vanesa; Ippolito, Davide

    2015-01-01

    Hybrid direct carbon fuel cells employ a classical solid oxide fuel cell together with carbon dispersed in a carbonate melt on the anode side. In a European project, the utilization of various coals has been investigated with and without addition of an oxidation catalyst to the carbon-carbonate s......Hybrid direct carbon fuel cells employ a classical solid oxide fuel cell together with carbon dispersed in a carbonate melt on the anode side. In a European project, the utilization of various coals has been investigated with and without addition of an oxidation catalyst to the carbon......-carbonate slurry or anode layer. The nature of the coal affects both open circuit voltage and power output. Highest OCV and power densities were observed for bituminous coal and by adding manganese oxide or praseodymium-doped ceria to the carbon/carbonate mixture. Comparing the carbon black fueled performance...... bituminous coal (73 mW/cm2). © 2015 ECS - The Electrochemical Society...

  20. Como traduzir a ordem das palavras na frase?

    OpenAIRE

    Batoréo, Hanna Krystyna Jakubowicz; Swiatkiewicz , Teresa Fernandes

    2015-01-01

    UID/LIN/03213/2013 The present study focuses on topicalization structures in translations from Polish into Portuguese based on a corpus of data collected from the Portuguese translation by Zbigniew Wódkowski of the Polish novel Tommaso del Cavaliere by Julian Stryjkowski. Both Polish and Portuguese are pro-drop languages and its basic sen- tence order is SVO, but because of its rich morphology Polish (like Slavic lan- guages in general) has very flexible word order, which causes syntactic ...

  1. Topic-Focus Articulation in Taqbaylit and Tashelhit Berber

    OpenAIRE

    Mettouchi, Amina; Fleisch, Axel

    2010-01-01

    This paper deals with the form/function mapping of information structure on word-order in two Berber lects, Taqbaylit (Kabyle) and Tashelhit (Shilha). We claim that the general assumption according to which Berber should be strictly VSO is wrong, and we argue for a more cautious approach, that takes into account language variation inside Berber. We show that pragmatics trigger the emergence of (relatively stable) discourse-confi gurationality, without giving rise to a VSO>SVO shift. We compar...

  2. Protein oxidation in aquatic foods

    DEFF Research Database (Denmark)

    Baron, Caroline P.

    2014-01-01

    The chapter discusses general considerations about protein oxidation and reviews the mechanisms involved in protein oxidation and consequences of protein oxidation on fish proteins. It presents two case studies, the first deals with protein and lipid oxidation in frozen rainbow trout......, and the second with oxidation in salted herring. The mechanisms responsible for initiation of protein oxidation are unclear, but it is generally accepted that free radical species initiating lipid oxidation can also initiate protein oxidation. The chapter focuses on interaction between protein and lipid...... oxidation. The protein carbonyl group measurement is the widely used method for estimating protein oxidation in foods and has been used in fish muscle. The chapter also talks about the impact of protein oxidation on protein functionality, fish muscle texture, and food nutritional value. Protein oxidation...

  3. Improved Understanding of In Situ Chemical Oxidation. Technical Objective I: Contaminant Oxidation Kinetics Contaminant Oxidation Kinetics

    Science.gov (United States)

    2009-05-01

    methyl tert butyl ether NAPL non-aqueous phase liquid NOD natural oxidant demand •OH hydroxide radical Ox oxidant O3 ozone PCE...and persulfate; and Technical Objective 2, assess how soil properties (e.g., soil mineralogy , natural carbon content) affect oxidant mobility and...to develop a general description of kobs vs. T because there are many reactions that can contribute to the concentration of the reactive intermediate

  4. Oxidation Resistant Graphite Studies

    Energy Technology Data Exchange (ETDEWEB)

    W. Windes; R. Smith

    2014-07-01

    The Very High Temperature Reactor (VHTR) Graphite Research and Development Program is investigating doped nuclear graphite grades exhibiting oxidation resistance. During a oxygen ingress accident the oxidation rates of the high temperature graphite core region would be extremely high resulting in significant structural damage to the core. Reducing the oxidation rate of the graphite core material would reduce the structural effects and keep the core integrity intact during any air-ingress accident. Oxidation testing of graphite doped with oxidation resistant material is being conducted to determine the extent of oxidation rate reduction. Nuclear grade graphite doped with varying levels of Boron-Carbide (B4C) was oxidized in air at nominal 740°C at 10/90% (air/He) and 100% air. The oxidation rates of the boronated and unboronated graphite grade were compared. With increasing boron-carbide content (up to 6 vol%) the oxidation rate was observed to have a 20 fold reduction from unboronated graphite. Visual inspection and uniformity of oxidation across the surface of the specimens were conducted. Future work to determine the remaining mechanical strength as well as graphite grades with SiC doped material are discussed.

  5. Oxidizer Scoping Studies

    Energy Technology Data Exchange (ETDEWEB)

    Chancellor, Christopher John [Los Alamos National Laboratory

    2016-11-07

    The purpose of this report is to present the results of the acceptable knowledge (AK) review of oxidizers present in active waste streams, provide a technical analysis of the oxidizers, and report the results of the scoping study testing. This report will determine the fastest burning oxidizer to be used in the development of a Test Plan for Preparation and Testing of Sorbents Mixed with Oxidizer found in Transuranic Waste (DWT-TP-001). The companion report, DWT-RPT-002, Sorbent Scoping Studies, contains similar information for sorbents identified during the AK review of TRU waste streams. The results of the oxidizer and sorbent scoping studies will be used to inform the QL1 test plan. The QL1 test results will support the development of a basis of knowledge document that will evaluate oxidizing chemicals and sorbents in TRU waste and provide guidance for treatment.

  6. The properties of protective oxide scales containing cerium on alloy 800H in oxidizing and oxidizing/sulphidizing environments

    NARCIS (Netherlands)

    Haanappel, V.A.C.; Haanappel, V.A.C.; Fransen, T.; Geerdink, Bert; Gellings, P.J.; Stroosnijder, M.F.

    1991-01-01

    The corrosion protection of oxide scales formed by electrophoretic deposition in a cerium-containing sol on Alloy 800H, a 32Ni-20Cr steel, followed by firing in air at 1123 K was studied in oxidizing and mixed oxidizing/sulphidizing environments at elevated temperatures. In particular, the influence

  7. Spectrographic determination of impurities in high-purity tantalum oxide and niobium oxide

    International Nuclear Information System (INIS)

    Anderson, S.T.G.; Russell, G.M.

    1990-01-01

    The development of spectrographic methods by direct current arc excitation and carrier distillation for the determination of impurities in tantalum and niobium oxides are described. Iron, silicon, aluminium, titanium, calcium, silver, tin, magnesium, and manganese can be determined in tantalum oxide and niobium oxide in concentrations ranging from 3 to 300 p.p.m. Niobium can be determined in tantalum oxide in concentrations ranging from 10 to 300 p.p.m. Tantalum cannot be determined in niobium oxide, and tungsten cannot be determined in either matrix as a result of the absence of sensitive lines in the spectra of these elements. Relative standard deviations of analyte element concentrations are in the region of 0,18 for tantalum oxide samples, and 0,13 for niobium oxide samples. A detailed laboratory method is included. 4 figs., 4 tabs., 3 refs

  8. Efficient synthesis of graphene oxide and the mechanisms of oxidation and exfoliation

    Science.gov (United States)

    Yuan, Rui; Yuan, Jing; Wu, Yanping; Chen, Lei; Zhou, Huidi; Chen, Jianmin

    2017-09-01

    An efficient method for the preparation of graphene oxide (GO) was descried through inducing the ultrasonic in the rate-determining step of oxidation processes. Both the transformation procedures and the detailed molecular behavior of parent graphene (PG), partially oxidized graphene (PGO) and GO in H2SO4 and aqueous solution were investigated by molecular dynamic simulation (MD) combining with experiments. The results obtained from MD simulation show that the addition of KMnO4 truly marked the beginning of the reaction which carried out from the border of PG flakes to the centre. This oxidation procedure was the rate-determining step and mainly contained three steps: the boundary carbon atoms oxidized, the distance of the corresponding interlayer enlarged and the oxidizing agent diffused into the unoxidized region, the processes was repeated until oxidized completely. So, the introducing ultrasonic in this section can accelerate not only the exfoliation of layers but also the diffusion of oxidizer and finally raises the oxidation efficiency dramatically. To further clarify these simulation results, the GO was prepared by the method mentioned above. The analyses results for the X-ray diffraction (XRD), Raman spectra and X-ray photoelectron spectroscopy (XPS) of the resulting GO show that the ultrasonic method could perfectly shortens the oxidation time from 12 h to 3 h and forms the higher degree of oxidation products with more carboxylic acid groups on its edges. Thus, this study provides a better understanding of the transformation procedures of graphite and proposes an efficient way to produce GOs suitable for various chemical modifications.

  9. Green oxidations: Titanium dioxide induced tandem oxidation coupling reactions

    OpenAIRE

    Jeena, Vineet; Robinson, Ross S

    2009-01-01

    Summary The application of titanium dioxide as an oxidant in tandem oxidation type processes is described. Under microwave irradiation, quinoxalines have been synthesized in good yields from the corresponding ?-hydroxyketones.

  10. Influence of rare earth oxides in the oxidation of chromia forming alloys

    International Nuclear Information System (INIS)

    Ramanathan, L.V.

    1989-01-01

    The influence of superficial application of rare earth oxides such as CeO sub(2), La sub(2)O sub(3), Nd sub(2)O sub(3), Sm sub(2)O sub(3), and Gd sub(2)O sub (3) to AISI 304 and 310 stainless steels, on their isothermal oxidation behavior at 900 sup(0) and 1000 sup(0)C, and cyclic oxidation behavior between 20 sup(0) and 1000 sup(0)C has been studied. The application of rare earth oxides (REO) has been found to increase the oxidation resistance at AISI 304. No significant improvements in oxidation resistance of AISI 310 were noted. The oxidation resistance of AISI 304 was highest in the presence of CeO sub(2) on its surface. The other REO in decreasing order of influence on oxidation resistance are La sub(2)O sub(3), Nd sub(2)O sub(3), Sm sub(2)O sub(3) and Gd sub(2)O sub(3). SEM investigations of the oxide scale morphology revealed that the improved resistance is probably due to the formation of a thin layer of fine grained compact Cr sub(2)O sub(3) and the higher adhesion of the scale to its increased plasticity. (author)

  11. Non-oxidative and oxidative torrefaction characterization and SEM observations of fibrous and ligneous biomass

    International Nuclear Information System (INIS)

    Chen, Wei-Hsin; Lu, Ke-Miao; Lee, Wen-Jhy; Liu, Shih-Hsien; Lin, Ta-Chang

    2014-01-01

    Highlights: • Non-oxidative and oxidative torrefaction of biomass is studied. • Two fibrous biomasses and two ligneous biomasses are tested. • SEM observations of four biomasses are provided. • Fibrous biomass is more sensitive to O 2 concentration than ligneous biomass. • The performance of non-oxidative torrefaction is better than that of oxidative torrefaction. - Abstract: Oxidative torrefaction is a method to reduce the operating cost of upgrading biomass. To understand the potential of oxidative torrefaction and its impact on the internal structure of biomass, non-oxidative and oxidative torrefaction of two fibrous biomass materials (oil palm fiber and coconut fiber) and two ligneous ones (eucalyptus and Cryptomeria japonica) at 300 °C for 1 h are studied and compared with each other. Scanning electron microscope (SEM) observations are also performed to explore the impact of torrefaction atmosphere on the lignocellulosic structure of biomass. The results indicate that the fibrous biomass is more sensitive to O 2 concentration than the ligneous biomass. In oxidative torrefaction, an increase in O 2 concentration decreases the solid yield. The energy yield is linearly proportional to the solid yield, which is opposite to the behavior of non-oxidative torrefaction. The performance of non-oxidative torrefaction is better than that of oxidative torrefaction. As a whole, ligneous biomass can be torrefied in oxidative environments at lower O 2 concentrations, whereas fibrous biomass is more suitable for non-oxidative torrefaction

  12. Central venous oxygenation: when physiology explains apparent discrepancies.

    Science.gov (United States)

    Squara, Pierre

    2014-11-10

    Central venous oxygen saturation (ScvO2) >70% or mixed venous oxygen saturation (SvO2) >65% is recommended for both septic and non-septic patients. Although it is the task of experts to suggest clear and simple guidelines, there is a risk of reducing critical care to these simple recommendations. This article reviews the basic physiological and pathological features as well as the metrological issues that provide clear evidence that SvO2 and ScvO2 are adaptative variables with large inter-patient variability. This variability is exemplified in a modeled population of 1,000 standard ICU patients and in a real population of 100 patients including 15,860 measurements. In these populations, it can be seen how optimizing one to three of the four S(c)vO2 components homogenized the patients and yields a clear dependency with the fourth one. This explains the discordant results observed in large studies where cardiac output was increased up to predetermined S(c)vO2 thresholds following arterial oxygen hemoglobin saturation, total body oxygen consumption needs and hemoglobin optimization. Although a systematic S(c)vO2 goal-oriented protocol can be statistically profitable before ICU admission, appropriate intensive care mandates determination of the best compromise between S(c)vO2 and its four components, taking into account the specific constraints of each individual patient.

  13. MDMA enhances emotional empathy and prosocial behavior.

    Science.gov (United States)

    Hysek, Cédric M; Schmid, Yasmin; Simmler, Linda D; Domes, Gregor; Heinrichs, Markus; Eisenegger, Christoph; Preller, Katrin H; Quednow, Boris B; Liechti, Matthias E

    2014-11-01

    3,4-Methylenedioxymethamphetamine (MDMA, 'ecstasy') releases serotonin and norepinephrine. MDMA is reported to produce empathogenic and prosocial feelings. It is unknown whether MDMA in fact alters empathic concern and prosocial behavior. We investigated the acute effects of MDMA using the Multifaceted Empathy Test (MET), dynamic Face Emotion Recognition Task (FERT) and Social Value Orientation (SVO) test. We also assessed effects of MDMA on plasma levels of hormones involved in social behavior using a placebo-controlled, double-blind, random-order, cross-over design in 32 healthy volunteers (16 women). MDMA enhanced explicit and implicit emotional empathy in the MET and increased prosocial behavior in the SVO test in men. MDMA did not alter cognitive empathy in the MET but impaired the identification of negative emotions, including fearful, angry and sad faces, in the FERT, particularly in women. MDMA increased plasma levels of cortisol and prolactin, which are markers of serotonergic and noradrenergic activity, and of oxytocin, which has been associated with prosocial behavior. In summary, MDMA sex-specifically altered the recognition of emotions, emotional empathy and prosociality. These effects likely enhance sociability when MDMA is used recreationally and may be useful when MDMA is administered in conjunction with psychotherapy in patients with social dysfunction or post-traumatic stress disorder. © The Author (2013). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

  14. El sesgo negativista y su repercusión en la conducta social: la influencia de las emociones en el comportamiento cooperativo

    Directory of Open Access Journals (Sweden)

    Laura E. Amaya-Durán

    2014-12-01

    Full Text Available El presente estudio pretende aportar información sobre la pertinencia de instrumentos para estudiar la influencia de las conductas emocionales en el comportamiento cooperativo; asimismo se logró analizar la asociación entre la Escala de Orientación de Valores Sociales (slider measure of social values [SVO] (Murphy, Ackermann & Handgraaf, 2011 y el desempeño en el juego del dilema del prisionero, y estudiar la capacidad de dos estímulos audiovisuales para inducir una conducta emocional valorada como negativa o positiva. El método utilizado se basó primero en determinar el grado de dependencia entre las medidas SVO y dilema del prisionero, que se definió mediante el estadístico x2 de Pearson, y segundo, en evaluar la capacidad de los estímulos audiovisuales para inducir una conducta emocional. Se utilizó un diseño pre-post, el Self-assessment Manikin (Bradley & Lang, 1994 y un reporte verbal escrito de estado de ánimo. Se contó con la participación voluntaria de 48 estudiantes universitarios de diferentes facultades. Los resultados no fueron significativamente concluyentes respecto a la asociación entre las medidas de conducta cooperativa y la orientación a valores sociales, aunque los videos utilizados como inductores de conducta emocional lograron evocar efectivamente los resultados esperados.

  15. Synthesis of graphene oxide through different oxidation degrees for solar cells

    Science.gov (United States)

    Zhang, Xiaoshan; Wang, Huan; Huang, Tianjiao; Wen, Lingling; Zhou, Liya

    2018-03-01

    Graphene is known as an electro-chemical material and widely used in electro-chemical devices, especially in solar cell. Decreasing the thickness of the layer is a critical way to improve the electrochemical property of solar cells as far as possible. Among the various oxidation approaches, presented herein is a facile approach, which is easier, less cost and more effective, environmental benign with the greener processing and without any requirement for post purification, towards the synthesis of graphene oxide (GO) with different oxidation degrees by potassium ferrate (K2FeO4). A modified method using less amount of oxidizing agent is reported herein. It is the pretreatment of the synthesis of graphite, which maintains the thermal cycle of the system. This novel reports to compound GO with controlled oxidation degrees can not only increase the quantity of oxygen-containing functional groups on GO surface, increase space between graphene oxide layer and facilitate the dispersion of graphene in aqueous solution. Thus, the modified method shows prospect for large-scale production of graphene oxide and its novel application, in addition to its derivative and market potential for solar cells.

  16. Anodic oxidation

    CERN Document Server

    Ross, Sidney D; Rudd, Eric J; Blomquist, Alfred T; Wasserman, Harry H

    2013-01-01

    Anodic Oxidation covers the application of the concept, principles, and methods of electrochemistry to organic reactions. This book is composed of two parts encompassing 12 chapters that consider the mechanism of anodic oxidation. Part I surveys the theory and methods of electrochemistry as applied to organic reactions. These parts also present the mathematical equations to describe the kinetics of electrode reactions using both polarographic and steady-state conditions. Part II examines the anodic oxidation of organic substrates by the functional group initially attacked. This part particular

  17. Oxidative Stress in Neurodegeneration

    Directory of Open Access Journals (Sweden)

    Varsha Shukla

    2011-01-01

    Full Text Available It has been demonstrated that oxidative stress has a ubiquitous role in neurodegenerative diseases. Major source of oxidative stress due to reactive oxygen species (ROS is related to mitochondria as an endogenous source. Although there is ample evidence from tissues of patients with neurodegenerative disorders of morphological, biochemical, and molecular abnormalities in mitochondria, it is still not very clear whether the oxidative stress itself contributes to the onset of neurodegeneration or it is part of the neurodegenerative process as secondary manifestation. This paper begins with an overview of how oxidative stress occurs, discussing various oxidants and antioxidants, and role of oxidative stress in diseases in general. It highlights the role of oxidative stress in neurodegenerative diseases like Alzheimer's, Parkinson's, and Huntington's diseases and amyotrophic lateral sclerosis. The last part of the paper describes the role of oxidative stress causing deregulation of cyclin-dependent kinase 5 (Cdk5 hyperactivity associated with neurodegeneration.

  18. Cerium oxide and platinum nanoparticles protect cells from oxidant-mediated apoptosis

    International Nuclear Information System (INIS)

    Clark, Andrea; Zhu Aiping; Sun Kai; Petty, Howard R.

    2011-01-01

    Catalytic nanoparticles represent a potential clinical approach to replace or correct aberrant enzymatic activities in patients. Several diseases, including many blinding eye diseases, are promoted by excessive oxidant stress due to reactive oxygen species (ROS). Cerium oxide and platinum nanoparticles represent two potentially therapeutic nanoparticles that de-toxify ROS. In the present study, we directly compare these two classes of catalytic nanoparticles. Cerium oxide and platinum nanoparticles were found to be 16 ± 2.4 and 1.9 ± 0.2 nm in diameter, respectively. Using surface plasmon-enhanced microscopy, we find that these nanoparticles associate with cells. Furthermore, cerium oxide and platinum nanoparticles demonstrated superoxide dismutase catalytic activity, but did not promote hemolytic or cytolytic pathways in living cells. Importantly, both cerium oxide and platinum nanoparticles reduce oxidant-mediated apoptosis in target cells as judged by the activation of caspase 3. The ability to diminish apoptosis may contribute to maintaining healthy tissues.

  19. Interface and oxide traps in high-κ hafnium oxide films

    International Nuclear Information System (INIS)

    Wong, H.; Zhan, N.; Ng, K.L.; Poon, M.C.; Kok, C.W.

    2004-01-01

    The origins of the interface trap generation and the effects of thermal annealing on the interface and bulk trap distributions are studied in detail. We found that oxidation of the HfO 2 /Si interface, removal of deep trap centers, and crystallization of the as-deposited film will take place during the post-deposition annealing (PDA). These processes will result in the removal of interface traps and deep oxide traps and introduce a large amount of shallow oxide traps at the grain boundaries of the polycrystalline film. Thus, trade-off has to be made in considering the interface trap density and oxide trap density when conducting PDA. In addition, the high interface trap and oxide trap densities of the HfO 2 films suggest that we may have to use the SiO 2 /HfO 2 stack or hafnium silicate structure for better device performance

  20. Oxidation mechanisms occurring in wines

    OpenAIRE

    Oliveira, Carla Maria; Ferreira, António César Silva; Freitas, Victor De; Silva, Artur M. S.

    2011-01-01

    The present review aims to show the state of the art on the oxidation mechanisms occurring in wines, as well as the methods to monitor, classify and diagnose wine oxidation. Wine oxidation can be divided in enzymatic oxidation and non-enzymatic oxidation. Enzymatic oxidation almost entirely occurs in grape must and is largely correlated with the content of hydroxycinnamates, such as caffeoyltartaric acid and paracoumaroyltartaric acid, and flavan-3-ols. Non-enzymatic oxidation, al...

  1. Oxidation of uraninite

    International Nuclear Information System (INIS)

    Janeczek, J.; Ewing, R.C.

    1993-06-01

    Samples of uraninite and pitchblende annealed at 1200 degrees C in H 2 , and untreated pitchblende were sequentially oxidized in air at 180-190 degrees C, 230 degrees C, and 300 degrees C. Uraninite and untreated pitchblende oxidized to the U 4 O 9 -type oxide, and their x-ray symmetry remained isometric up to 300 degrees C. Reduced pitchblende, after oxidation to UO 2+x and U 4 O 9 -type oxides, transformed into α-U 3 O 8 at 300 degrees C. Two major mechanisms control uraninite and untreated pitchblende stability during oxidation: 1. Th and/or lanthanide elements maintain charge balance and block oxygen interstitials near impurity cations; 2. the uraninite structure saturates with respect to excess and radiation-induced oxygen interstitials. Untreated pitchblende during oxidation behaved similarly to irradiated UO 2 in spent nuclear fuel; whereas, reduced pitchblende resembled non-irradiated UO 2 . An analysis of the data in the literature, as well as our own efforts (XRD, EMPA, SEM, AEM) to identify U 3 O 7 in samples form Cigar Lake, Canada, failed to provide conclusive evidence of the natural occurrence of tetragonal αU 3 O 7 . Most probably, reported occurrences of U 3 O 7 are mixtures of isometric uraninites of slightly different compositions, 45 refs

  2. Anaerobic ammonium oxidation mediated by Mn-oxides: from sediment to strain level.

    Science.gov (United States)

    Javanaud, Cedric; Michotey, Valerie; Guasco, Sophie; Garcia, Nicole; Anschutz, Pierre; Canton, Mathieu; Bonin, Patricia

    2011-11-01

    Nitrite and (29)N(2) productions in slurry incubations of anaerobically sediment after (15)NO(3) or (15)NH(4) labelling in the presence of Mn-oxides suggested that anaerobic Mn-oxides mediated nitrification coupled with denitrification in muddy intertidal sediments of Arcachon Bay (SW Atlantic French coast). From this sediment, bacterial strains were isolated and physiologically characterized in terms of Mn-oxides and nitrate reduction as well as potential anaerobic nitrification. One of the isolated strain, identified as Marinobacter daepoensis strain M4AY14, was a denitrifier. Nitrous oxide production by this strain was demonstrated in the absence of nitrate and with Mn-oxides and NH(4) amendment, giving indirect proof of anaerobic nitrate or nitrite production. Anaerobic Mn-oxide-mediated nitrification was confirmed by (29)N(2) production in the presence of (15)NO(3) and (14)NH(4) under denitrifying conditions. Anaerobic nitrification by M4AY14 seemed to occur only in the absence of nitrate, or at nitrate levels lower than that of Mn-oxides. Most of the other isolates were affiliated with the Shewanella genus and were able to use both nitrate and Mn-oxides as electron acceptors. When both electron acceptors were present, whatever their concentrations, nitrate and Mn-oxide reduction co-occurred. These data indicate that bacterial Mn-oxide reduction could be an important process in marine sediments with low oxygen concentrations, and demonstrate for the first time the role of bacteria in anaerobic Mn-mediated nitrification. Copyright © 2011 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

  3. Thermally exfoliated graphite oxide

    Science.gov (United States)

    Prud'Homme, Robert K. (Inventor); Aksay, Ilhan A. (Inventor); Abdala, Ahmed (Inventor)

    2011-01-01

    A modified graphite oxide material contains a thermally exfoliated graphite oxide with a surface area of from about 300 sq m/g to 2600 sq m/g, wherein the thermally exfoliated graphite oxide displays no signature of the original graphite and/or graphite oxide, as determined by X-ray diffraction.

  4. Kinetic and catalytic analysis of mesoporous metal oxides on the oxidation of Rhodamine B

    Science.gov (United States)

    Xaba, Morena S.; Noh, Ji-Hyang; Mokgadi, Keabetswe; Meijboom, Reinout

    2018-05-01

    In this study, we demonstrate the synthesis and catalytic activity of different mesoporous transition metal oxides, silica (SiO2), copper oxide (CuO), chromium oxide (Cr2O3), iron oxide (Fe2O3) cobalt oxide (Co3O4), cerium oxide (CeO2) and nickel oxide (NiO), on the oxidation of a pollutant dye, Rhodamine B (RhB). These metal oxides were synthesized by inverse micelle formation method and characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), adsorption-desorption isotherms (BET) and H2-temperature programmed reduction (TPR). UV-vis spectrophotometry was used to monitor the time-resolved absorbance of RhB at λmax = 554 nm. Mesoporous copper oxide was calcined at different final heating temperatures of 250, 350, 450 and 550 °C, and each mesoporous copper oxide catalyst showed unique physical properties and catalytic behavior. Mesoporous CuO-550 with the smallest characteristic path length δ, proved to be the catalyst of choice for the oxidation of RhB in aqueous media. We observed that the oxidation of RhB in aqueous media is dependent on the crystallite size and characteristic path length of the mesoporous metal oxide. The Langmuir-Hinshelwood model was used to fit the experimental data and to prove that the reaction occurs on the surface of the mesoporous CuO. The thermodynamic parameters, EA, ΔH#, ΔS# and ΔG# were calculated and catalyst recycling and reusability were demonstrated.

  5. Oxidant/antioxidant balance in animal nutrition and health: the role of protein oxidation

    Directory of Open Access Journals (Sweden)

    Pietro eCeli

    2015-10-01

    Full Text Available This review examines the role that oxidative stress, and protein oxidation in particular, plays in nutrition, metabolism and health of farm animals. The route by which redox homeostasis is involved in some important physiological functions and the implications of the impairment of oxidative status on animal health and diseases is also examined. Proteins have various and, at the same time, unique biological functions and their oxidation can result in structural changes and various functional modifications. Protein oxidation seems to be involved in pathological conditions such as respiratory diseases and parasitic infection; however some studies also suggest that protein oxidation plays a crucial role in the regulation of important physiological functions such as reproduction, nutrition, metabolism, lactation, gut health and neonatal physiology. As the characterization of the mechanisms by which oxidative stress may influence metabolism and health is attracting considerable scientific interest, the aim of this review is to present veterinary scientists and clinicians with various aspects of oxidative damage to proteins.

  6. High temperature oxidation test of oxide dispersion strengthened (ODS) steel claddings

    International Nuclear Information System (INIS)

    Narita, Takeshi; Ukai, Shigeharu; Kaito, Takeji; Ohtsuka, Satoshi; Matsuda, Yasushi

    2006-07-01

    In a feasibility study of ODS steel cladding, its high temperature oxidation resistance was evaluated. Although addition of Cr is effective for preventing high temperature oxidation, excessively higher amount of Cr leads to embrittlement due to the Cr-rich α' precipitate formation. In the ODS steel developed by the Japan Atomic Energy Agency (JAEA), the Cr content is controlled in 9Cr-ODS martensite and 12Cr-ODS ferrite. In this study, high temperature oxidation test was conducted for ODS steels, and their results were compared with that of conventional austenitic stainless steel and ferritic-martensitic stainless steel. Following results were obtained in this study. (1) 9Cr-ODS martensitic and 12Cr-ODS ferritic steel have superior high temperature oxidation resistance compared to 11mass%Cr PNC-FMS and even 17mass% SUS430 and equivalent to austenitic PNC316. (2) The superior oxidation resistance of ODS steel was attributed to earlier formation of the protective alpha-Cr 2 O 3 layer at the matrix and inner oxide scale interface. The grain size of ODS steel is finer than that of PNC-FMS, so the superior oxidation resistance of ODS steel can be attributed to the enhanced Cr-supplying rate throughout the accelerated grain boundary diffusion. Finely dispersed Y 2 O 3 oxide particles in the ODS steel matrix may also stabilized the adherence between the protective alpha-Cr 2 O 3 layer and the matrix. (author)

  7. "A New Class of Creep Resistant Oxide/Oxide Ceramic Matrix Composites"

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Mohit Jain, Dr. Ganesh Skandan, Prof. Roger Cannon, Rutgers University

    2007-03-30

    Despite recent progress in the development of SiC-SiC ceramic matrix composites (CMCs), their application in industrial gas turbines for distributed energy (DE) systems has been limited. The poor oxidation resistance of the non-oxide ceramics warrants the use of envrionmental barrier coatings (EBCs), which in turn lead to issues pertaining to life expectancy of the coatings. On the other hand, oxide/oxide CMCs are potential replacements, but their use has been limited until now due to the poor creep resistance at high temperatures, particularly above 1200 oC: the lack of a creep resistant matrix has been a major limiting factor. Using yttrium aluminum garnet (YAG) as the matrix material system, we have advanced the state-of-the-art in oxide/oxide CMCs by introducing innovations in both the structure and composition of the matrix material, thereby leading to high temperature matrix creep properties not achieved until now. An array of YAG-based powders with a unique set of particle characteristics were produced in-house and sintered to full density and compressive creep data was obtained. Aided in part by the composition and the microstructure, the creep rates were found to be two orders of magnitude smaller than the most creep resistant oxide fiber available commercially. Even after accounting for porosity and a smaller matrix grain size in a practical CMC component, the YAG-based matrix material was found to creep slower than the most creep resistant oxide fiber available commercially.

  8. An engineered polypeptide around nano-sized manganese-calcium oxide: copying plants for water oxidation.

    Science.gov (United States)

    Najafpour, Mohammad Mahdi; Ghobadi, Mohadeseh Zarei; Sarvi, Bahram; Haghighi, Behzad

    2015-09-14

    Synthesis of new efficient catalysts inspired by Nature is a key goal in the production of clean fuel. Different compounds based on manganese oxide have been investigated in order to find their water-oxidation activity. Herein, we introduce a novel engineered polypeptide containing tyrosine around nano-sized manganese-calcium oxide, which was shown to be a highly active catalyst toward water oxidation at low overpotential (240 mV), with high turnover frequency of 1.5 × 10(-2) s(-1) at pH = 6.3 in the Mn(III)/Mn(IV) oxidation range. The compound is a novel structural and efficient functional model for the water-oxidizing complex in Photosystem II. A new proposed clever strategy used by Nature in water oxidation is also discussed. The new model of the water-oxidizing complex opens a new perspective for synthesis of efficient water-oxidation catalysts.

  9. Size of oxide vacancies in fluorite and perovskite structured oxides

    DEFF Research Database (Denmark)

    Chatzichristodoulou, Christodoulos; Norby, Poul; Hendriksen, Peter Vang

    2015-01-01

    An analysis of the effective radii of vacancies and the stoichiometric expansion coefficient is performed on metal oxides with fluorite and perovskite structures. Using the hard sphere model with Shannon ion radii we find that the effective radius of the oxide vacancy in fluorites increases...... with increasing ion radius of the host cation and that it is significantly smaller than the radius of the oxide ion in all cases, from 37% smaller for HfO2 to 13 % smaller for ThO2. The perovskite structured LaGaO3 doped with Sr or Mg or both is analyzed in some detail. The results show that the effective radius...... of an oxide vacancy in doped LaGaO3 is only about 6 % smaller than the oxide ion. In spite of this the stoichiometric expansion coefficient (a kind of chemical expansion coefficient) of the similar perovskite, LaCrO3, is significantly smaller than the stoichiometric expansion coefficient of the fluorite...

  10. X-ray Absorption Study of Graphene Oxide and Transition Metal Oxide Nanocomposites

    OpenAIRE

    Gandhiraman, Ram P.; Nordlund, Dennis; Javier, Cristina; Koehne, Jessica E.; Chen, Bin; Meyyappan, M.

    2014-01-01

    The surface properties of the electrode materials play a crucial role in determining the performance and efficiency of energy storage devices. Graphene oxide and nanostructures of 3d transition metal oxides were synthesized for construction of electrodes in supercapacitors, and the electronic structure and oxidation states were probed using near-edge X-ray absorption fine structure. Understanding the chemistry of graphene oxide would provide valuable insight into its reactivity and properties...

  11. Near-infrared spectroscopy during stagnant ischemia estimates central venous oxygen saturation and mixed venous oxygen saturation discrepancy in patients with severe left heart failure and additional sepsis/septic shock

    OpenAIRE

    Mo?ina, Hugo; Podbregar, Matej

    2010-01-01

    Introduction Discrepancies of 5-24% between superior vena cava oxygen saturation (ScvO2) and mixed venous oxygen saturation (SvO2) have been reported in patients with severe heart failure. Thenar muscle tissue oxygenation (StO2) measured with near-infrared spectroscopy (NIRS) during arterial occlusion testing decreases slower in sepsis/septic shock patients (lower StO2 deoxygenation rate). The StO2 deoxygenation rate is influenced by dobutamine. The aim of this study was to determine the rela...

  12. Oxidation of zirconium alloys in steam: influence of tetragonal zirconia on oxide growth mechanism

    International Nuclear Information System (INIS)

    Godlewski, J.

    1990-07-01

    The oxidation of zirconium alloys in presence of steam, presents after a 'parabolic' growth law, an acceleration of the oxidation velocity. This phenomenon limits the use of zirconium alloys as nuclear fuel cladding element. In order to determine the physico-chemical process leading to this kinetic transition, two approaches have been carried out: the first one has consisted to determine the composition of the oxide layer and its evolution with the oxidation time; and the second one to determine the oxygen diffusion coefficients in the oxide layers of pre- and post-transition as well as their evolution with the oxidation time. The composition of the oxide layers has been determined by two analyses techniques: the X-ray diffraction and the laser Raman spectroscopy. This last method has allowed to confirm the presence of tetragonal zirconium oxide in the oxide layers. Analyses carried out by laser Raman spectroscopy on oxides oblique cuttings have revealed that the tetragonal zirconium oxide is transformed in monoclinic phase during the kinetic transition. A quantitative approach has allowed to corroborate the results obtained by these two techniques. In order to determine the oxygen diffusion coefficients in the oxides layers, two diffusion treatments have been carried out: 1)under low pressure with D 2 18 O 2 ) under high pressure in an autoclave with H 2 18 O. The oxygen 18 concentration profiles have been obtained by two analyses techniques: the nuclear microprobe and the secondary ions emission spectroscopy. The obtained profiles show that the mass transport is made by the volume and particularly by the grain boundaries. The corresponding diffusion coefficients have been calculated with the WHIPPLE and LE CLAIRE solution. The presence of tetragonal zirconium oxide, its relation with the kinetic transition, and the evolution of the diffusion coefficients with the oxidation time, are discussed in terms of internal stresses in the oxide layer and of the oxide layer

  13. Sputtered indium oxide films

    International Nuclear Information System (INIS)

    Gillery, F.H.

    1986-01-01

    A method is described for depositing on a substrate multiple layer films comprising at least one primary layer of a metal oxide and at least one primary layer of a metal other than the metal of the oxide layer. The improvement described here comprises improving the adhesion between the metal oxide and metal layers by depositing between the layers an intermediate metal-containing layer having an affinity for both the metal and metal oxide layers. An article of manufacture is described comprising a nonmetallic substrate, and deposited thereon in any order: a. at least one coating layer of metal; b. at least one coating layer of an oxide of a metal other than the metal of the metal layer; and c. deposited between the metal and metal oxide layers an intermediate metal-containing layer having an affinity for both the metal and metal oxide layers

  14. Studies on O/M ratio determination in uranium oxide, plutonium oxide and uranium-plutonium mixed oxide

    International Nuclear Information System (INIS)

    Sampath, S.; Chawla, K.L.

    1975-01-01

    Thermogravimetric studies were carried out in unsintered and sintered samples of uranium oxide, plutonium oxide and uranium-plutonium mixed oxide under different atmospheric conditions (air, argon and moist argon/hydrogen). Moisture loss was found to occur below 200 0 C for uranium dioxide samples, upto 700 0 C for sintered plutonium dioxide and negligible for sintered samples. The O/M ratios for non-stoichiometric uranium dioxide (sintered and unsintered), plutonium dioxide and mixed uranium and plutonium oxides (sintered) could be obtained with a precision of +- 0.002. Two reference states UOsub(2.000) and UOsub(2.656) were obtained for uranium dioxide and the reference state MOsub(2.000) was used for other cases. For unsintered plutonium dioxide samples, accurate O/M ratios could not be obtained of overlap of moisture loss with oxygen loss/gain. (author)

  15. Actinide oxide photodiode and nuclear battery

    Energy Technology Data Exchange (ETDEWEB)

    Sykora, Milan; Usov, Igor

    2017-12-05

    Photodiodes and nuclear batteries may utilize actinide oxides, such a uranium oxide. An actinide oxide photodiode may include a first actinide oxide layer and a second actinide oxide layer deposited on the first actinide oxide layer. The first actinide oxide layer may be n-doped or p-doped. The second actinide oxide layer may be p-doped when the first actinide oxide layer is n-doped, and the second actinide oxide layer may be n-doped when the first actinide oxide layer is p-doped. The first actinide oxide layer and the second actinide oxide layer may form a p/n junction therebetween. Photodiodes including actinide oxides are better light absorbers, can be used in thinner films, and are more thermally stable than silicon, germanium, and gallium arsenide.

  16. Porous ceramics out of oxides

    International Nuclear Information System (INIS)

    Bakunov, V.S.; Balkevich, V.L.; Vlasov, A.S.; Guzman, I.Ya.; Lukin, E.S.; Poluboyarinov, D.N.; Poliskij, R.Ya.

    1977-01-01

    A review is made of manufacturing procedures and properties of oxide ceramics intended for high-temperature thermal insulation and thermal protection applications. Presented are structural characteristics of porous oxide refractories and their properties. Strength and thermal conductivity was shown to depend upon porosity. Described is a procedure for manufacturing porous ceramic materials from aluminium oxide, zirconium dioxide, magnesium oxide, beryllium oxide. The thermal resistance of porous ceramics from BeO is considerably greater than that of other high-refractoriness oxides. Listed are areas of application for porous materials based on oxides

  17. Thermal oxidation of silicon with two oxidizing species

    International Nuclear Information System (INIS)

    Vild-Maior, A.A.; Filimon, S.

    1979-01-01

    A theoretical model for the thermal oxidation of silicon in wet oxygen is presented. It is shown that the presence of oxygen in the oxidation furnace has an important effect when the water temperature is not too high (less than about 65 deg C). The model is in good agreement with the experimental data. (author)

  18. Staphylococcal response to oxidative stress

    Directory of Open Access Journals (Sweden)

    Rosmarie eGaupp

    2012-03-01

    Full Text Available Staphylococci are a versatile genus of bacteria that are capable of causing acute and chronic infections in diverse host species. The success of staphylococci as pathogens is due in part to their ability to mitigate endogenous and exogenous oxidative and nitrosative stress. Endogenous oxidative stress is a consequence of life in an aerobic environment; whereas, exogenous oxidative and nitrosative stress are often due to the bacteria’s interaction with host immune systems. To overcome the deleterious effects of oxidative and nitrosative stress, staphylococci have evolved protection, detoxification, and repair mechanisms that are controlled by a network of regulators. In this review, we summarize the cellular targets of oxidative stress, the mechanisms by which staphylococci sense oxidative stress and damage, oxidative stress protection and repair mechanisms, and regulation of the oxidative stress response. When possible, special attention is given to how the oxidative stress defense mechanisms help staphylococci control oxidative stress in the host.

  19. SPH based modelling of oxide and oxide film formation in gravity die castings

    International Nuclear Information System (INIS)

    Ellingsen, K; M'Hamdi, M; Coudert, T

    2015-01-01

    Gravity die casting is an important casting process which has the capability of making complicated, high-integrity components for e.g. the automotive industry. Oxides and oxide films formed during filling affect the cast product quality. The Smoothed particle hydrodynamics (SPH) method is particularly suited to follow complex flows. The SPH method has been used to study filling of a gravity die including the formation and transport of oxides and oxide films for two different filling velocities. A low inlet velocity leads to a higher amount of oxides and oxide films in the casting. The study demonstrates the usefulness of the SPH method for an increased understanding of the effect of different filling procedures on the cast quality. (paper)

  20. Review Of Plutonium Oxidation Literature

    International Nuclear Information System (INIS)

    Korinko, P.

    2009-01-01

    A brief review of plutonium oxidation literature was conducted. The purpose of the review was to ascertain the effect of oxidation conditions on oxide morphology to support the design and operation of the PDCF direct metal oxidation (DMO) furnace. The interest in the review was due to a new furnace design that resulted in oxide characteristics that are different than those of the original furnace. Very little of the published literature is directly relevant to the DMO furnace operation, which makes assimilation of the literature data with operating conditions and data a convoluted task. The oxidation behavior can be distilled into three regimes, a low temperature regime (RT to 350 C) with a relatively slow oxidation rate that is influenced by moisture, a moderate temperature regime (350-450 C) that is temperature dependent and relies on more or less conventional oxidation growth of a partially protective oxide scale, and high temperature oxidation (> 500 C) where the metal autocatalytically combusts and oxidizes. The particle sizes obtained from these three regimes vary with the finest being from the lowest temperature. It is surmised that the slow growth rate permits significant stress levels to be achieved that help break up the oxides. The intermediate temperatures result in a fairly compact scale that is partially protective and that grows to critical thickness prior to fracturing. The growth rate in this regime may be parabolic or paralinear, depending on the oxidation time and consequently the oxide thickness. The high temperature oxidation is invariant in quiescent or nearly quiescent conditions due to gas blanketing while it accelerates with temperature under flowing conditions. The oxide morphology will generally consist of fine particles ( 250 (micro)m). The particle size ratio is expected to be < 5%, 25%, and 70% for fine, medium and large particles, respectively, for metal temperatures in the 500-600 C range.

  1. Synthesis of Graphene Oxide by Oxidation of Graphite with Ferrate(VI) Compounds: Myth or Reality?

    Science.gov (United States)

    Sofer, Zdeněk; Luxa, Jan; Jankovský, Ondřej; Sedmidubský, David; Bystroň, Tomáš; Pumera, Martin

    2016-09-19

    It is well established that graphene oxide can be prepared by the oxidation of graphite using permanganate or chlorate in an acidic environment. Recently, however, the synthesis of graphene oxide using potassium ferrate(VI) ions has been reported. Herein, we critically replicate and evaluate this new ferrate(VI) oxidation method. In addition, we test the use of potassium ferrate(VI) for the synthesis of graphene oxide under various experimental routes. The synthesized materials are analyzed by a number of analytical methods in order to confirm or disprove the possibility of synthesizing graphene oxide by the ferrate(VI) oxidation route. Our results confirm the unsuitability of using ferrate(VI) for the oxidation of graphite on graphene oxide because of its high instability in an acidic environment and low oxidation power in neutral and alkaline environments. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Oxidation of Ethylene Carbonate on Li Metal Oxide Surfaces

    DEFF Research Database (Denmark)

    Østergaard, Thomas M.; Giordano, Livia; Castelli, Ivano Eligio

    2018-01-01

    Understanding the reactivity of the cathode surface is of key importance to the development of batteries. Here, density functional theory is applied to investigate the oxidative decomposition of the electrolyte component, ethylene carbonate (EC), on layered LixMO(2) oxide surfaces. We compare...

  3. Oxide surfaces and metal/oxide interfaces studied by grazing incidence X-ray scattering

    Science.gov (United States)

    Renaud, Gilles

    Experimental determinations of the atomic structure of insulating oxide surfaces and metal/oxide interfaces are scarce, because surface science techniques are often limited by the insulating character of the substrate. Grazing incidence X-ray scattering (GIXS), which is not subject to charge effects, can provide very precise information on the atomic structure of oxide surfaces: roughness, relaxation and reconstruction. It is also well adapted to analyze the atomic structure, the registry, the misfit relaxation, elastic or plastic, the growth mode and the morphology of metal/oxide interfaces during their growth, performed in situ. GIXS also allows the analysis of thin films and buried interfaces, in a non-destructive way, yielding the epitaxial relationships, and, by variation of the grazing incidence angle, the lattice parameter relaxation along the growth direction. On semi-coherent interfaces, the existence of an ordered network of interfacial misfit dislocations can be demonstrated, its Burger's vector determined, its ordering during in situ annealing cycles followed, and sometimes even its atomic structure can be addressed. Careful analysis during growth allows the modeling of the dislocation nucleation process. This review emphasizes the new information that GIXS can bring to oxide surfaces and metal/oxide interfaces by comparison with other surface science techniques. The principles of X-ray diffraction by surfaces and interfaces are recalled, together with the advantages and properties of grazing angles. The specific experimental requirements are discussed. Recent results are presented on the determination of the atomic structure of relaxed or reconstructed oxide surfaces. A description of results obtained during the in situ growth of metal on oxide surfaces is also given, as well as investigations of thick metal films on oxide surfaces, with lattice parameter misfit relaxed by an array of dislocations. Recent work performed on oxide thin films having

  4. Oxidation of zirconium-aluminum alloys

    International Nuclear Information System (INIS)

    Cox, B.

    1967-10-01

    Examination of the processes occurring during the oxidation of Zr-1% A1, Zr-3% A1, and Zr-1.5% A1-0.5% Mo alloys has shown that in steam rapid oxidation occurs predominantly around the Zr 3 A1 particles, which at low temperatures appear to be relatively unattacked. The unoxidised particles become incorporated in the oxide, and become fully oxidised as the film thickens. This rapid localised oxidation is preceded by a short period of uniform film growth, during which the oxide film thickness does not exceed ∼200A-o. Thus the high oxidation rates can probably be ascribed to aluminum in solution in the zirconium matrix, although its precise mode of operation has not been determined. Once the solubility limit of aluminum is exceeded, the size, distribution and number of intermetallic particles affects the oxidation rate merely by altering the distribution of regions of metal giving high oxidation rates. The controlling process during the early stages of oxidation is electron transport and not ionic transport. Thus, the aluminum in the oxide film is presumably increasing the ionic conductivity more than the electronic. The oxidation rates in atmospheric pressure steam are very high and their irregular temperature dependence suggests that the oxidation rate will be pressure dependent. This was confirmed, in part, by a comparison with oxidation in moist air. It was found that the rate of development of white oxide around intermetallic particles was considerably reduced by the decrease in the partial pressure of H 2 O; the incubation period was not much different, however. (author)

  5. Highly Conductive One-Dimensional Manganese Oxide Wires by Coating with Graphene Oxides

    Science.gov (United States)

    Tojo, Tomohiro; Shinohara, Masaki; Fujisawa, Kazunori; Muramatsu, Hiroyuki; Hayashi, Takuya; Ahm Kim, Yoong; Endo, Morinobu

    2012-10-01

    Through coating with graphene oxides, we have developed a chemical route to the bulk production of long, thin manganese oxide (MnO2) nanowires that have high electrical conductivity. The average diameter of these hybrid nanowires is about 25 nm, and their average length is about 800 nm. The high electrical conductivity of these nanowires (ca. 189.51+/-4.51 µS) is ascribed to the homogeneous coating with conductive graphene oxides as well as the presence of non-bonding manganese atoms. The growth mechanism of the nanowires is theoretically supported by the initiation of morphological conversion from graphene oxide to wrapped structures through the formation of covalent bonds between manganese and oxygen atoms at the graphene oxide edge.

  6. Oxidative stress

    Directory of Open Access Journals (Sweden)

    Osredkar Joško

    2012-05-01

    Full Text Available The human organism is exposed to the influence of various forms of stress, either physical, psychological or chemical, which all have in common that they may adversely affect our body. A certain amount of stress is always present and somehow directs, promotes or inhibits the functioning of the human body. Unfortunately, we are now too many and too often exposed to excessive stress, which certainly has adverse consequences. This is especially true for a particular type of stress, called oxidative stress. All aerobic organisms are exposed to this type of stress because they produce energy by using oxygen. For this type of stress you could say that it is rather imperceptibly involved in our lives, as it becomes apparent only at the outbreak of certain diseases. Today we are well aware of the adverse impact of radicals, whose surplus is the main cause of oxidative stress. However, the key problem remains the detection of oxidative stress, which would allow us to undertake timely action and prevent outbreak of many diseases of our time. There are many factors that promote oxidative stress, among them are certainly a fast lifestyle and environmental pollution. The increase in oxidative stress can also trigger intense physical activity that is directly associated with an increased oxygen consumption and the resulting formation of free radicals. Considering generally positive attitude to physical activity, this fact may seem at first glance contradictory, but the finding has been confimed by several studies in active athletes. Training of a top athlete daily demands great physical effort, which is also reflected in the oxidative state of the organism. However, it should be noted that the top athletes in comparison with normal individuals have a different defense system, which can counteract the negative effects of oxidative stress. Quite the opposite is true for irregular or excessive physical activity to which the body is not adapted.

  7. Nitric oxide: a physiologic messenger.

    Science.gov (United States)

    Lowenstein, C J; Dinerman, J L; Snyder, S H

    1994-02-01

    To review the physiologic role of nitric oxide, an unusual messenger molecule that mediates blood vessel relaxation, neurotransmission, and pathogen suppression. A MEDLINE search of articles published from 1987 to 1993 that addressed nitric oxide and the enzyme that synthesizes it, nitric oxide synthase. Animal and human studies were selected from 3044 articles to analyze the clinical importance of nitric oxide. Descriptions of the structure and function of nitric oxide synthase were selected to show how nitric oxide acts as a biological messenger molecule. Biochemical and physiologic studies were analyzed if the same results were found by three or more independent observers. Two major classes of nitric oxide synthase enzymes produce nitric oxide. The constitutive isoforms found in endothelial cells and neurons release small amounts of nitric oxide for brief periods to signal adjacent cells, whereas the inducible isoform found in macrophages releases large amounts of nitric oxide continuously to eliminate bacteria and parasites. By diffusing into adjacent cells and binding to enzymes that contain iron, nitric oxide plays many important physiologic roles. It regulates blood pressure, transmits signals between neurons, and suppresses pathogens. Excess amounts, however, can damage host cells, causing neurotoxicity during strokes and causing the hypotension associated with sepsis. Nitric oxide is a simple molecule with many physiologic roles in the cardiovascular, neurologic, and immune systems. Although the general principles of nitric oxide synthesis are known, further research is necessary to determine what role it plays in causing disease.

  8. Influence of vanadium oxidation states on the performance of V-Mg-Al mixed-oxide catalysts for the oxidative dehydrogenation of propane

    International Nuclear Information System (INIS)

    Schacht, L.; Navarrete, J.; Schacht, P.; Ramirez, M. A.

    2010-01-01

    V-Mg-Al mixed-oxide catalysts for oxidative dehydrogenation of propane were prepared by thermal decomposition of Mg-Al-layered double hydroxides with vanadium interlayer doping. The obtained catalysts were tested for the oxidative dehydrogenation of propane, obtaining good results in catalytic activity (conversion 16.55 % and selectivity 99.97 %) Results indicated that catalytic performance of these materials depends on how vanadium is integrated in the layered structure, which is determined by the Mg/Al ratio. Vanadium interlayer doping modifies the oxidation state of vanadium and consequently catalytic properties. Surface properties were studied by X-ray photoelectron spectroscopic and diffuse reflectance, UV-visible spectroscopy, and temperature programmed reduction. The analyses provided information about the oxidation state, before and after the reaction. From these results, it is suggested that selectivity to propylene and catalytic activity depend mainly of vanadium oxidation state. (Author)

  9. Influence of vanadium oxidation states on the performance of V-Mg-Al mixed-oxide catalysts for the oxidative dehydrogenation of propane

    Energy Technology Data Exchange (ETDEWEB)

    Schacht, L. [IPN, Escuela Superior de Fisica y Matematicas, Departamento de Ciencia de Materiales, Av. IPN s/n, Edificio 9, Col. Lindavista, 07738 Mexico D. F. (Mexico); Navarrete, J.; Schacht, P.; Ramirez, M. A., E-mail: pschacha@imp.m [Instituto Mexicano del Petroleo, Programa de Ingenieria Molecular, Eje Central Lazaro Cardenas No. 152, 07730 Mexico D. F. (Mexico)

    2010-07-01

    V-Mg-Al mixed-oxide catalysts for oxidative dehydrogenation of propane were prepared by thermal decomposition of Mg-Al-layered double hydroxides with vanadium interlayer doping. The obtained catalysts were tested for the oxidative dehydrogenation of propane, obtaining good results in catalytic activity (conversion 16.55 % and selectivity 99.97 %) Results indicated that catalytic performance of these materials depends on how vanadium is integrated in the layered structure, which is determined by the Mg/Al ratio. Vanadium interlayer doping modifies the oxidation state of vanadium and consequently catalytic properties. Surface properties were studied by X-ray photoelectron spectroscopic and diffuse reflectance, UV-visible spectroscopy, and temperature programmed reduction. The analyses provided information about the oxidation state, before and after the reaction. From these results, it is suggested that selectivity to propylene and catalytic activity depend mainly of vanadium oxidation state. (Author)

  10. Improving Thermo-Oxidative Stability of Nitrile Rubber Composites by Functional Graphene Oxide.

    Science.gov (United States)

    Zhong, Rui; Zhang, Zhao; Zhao, Hongguo; He, Xianru; Wang, Xin; Zhang, Rui

    2018-05-30

    Graphene oxide (GO), modified with anti-aging agent p -phenylenediamine (PPD), was added into nitrile rubber (NBR) in order to improve the thermo-oxidative stability of NBR. The modification of GO and the transformation of functional groups were characterized by Fourier transform infrared spectroscopy (FTIR), Raman, and X-ray diffraction (XRD). Mechanical performances of NBR composites before and after the thermo-oxidative aging were recorded. The results of dynamic mechanical analysis (DMA) show an increased storage modulus (G') and a decreased value of area of tan δ peak after introducing modified GO into NBR. It indicates that filler particles show positive interaction with molecular chains. The thermo-oxidative stability of composites was investigated by thermogravimetric analysis (TG) and differential scanning calorimetry (DSC). Then, the thermo-oxidative aging kinetic parameters were obtained by the Flynn⁻Wall⁻Ozawa (FWO) equation. The results of aging tests show that the thermo-oxidative stability of rubber matrix increases obviously after introducing GO⁻PPD. In addition, mechanical properties (tensile strength and elongation at break) of both before and after aged NBR/GO⁻PPD composites were superior to that of NBR. This work provides meaningful guidance for achieving multifunction thermo-oxidative aging resistance rubber composites.

  11. Catalytic Oxidation of Cyanogen Chloride over a Monolithic Oxidation Catalyst

    National Research Council Canada - National Science Library

    Campbell, Jeffrey

    1997-01-01

    The catalytic oxidation of cyanogen chloride was evaluated over a monolithic oxidation catalyst at temperatures between 200 and 300 deg C in air employing feed concentrations between 100 and 10,000 ppm...

  12. Reversible solid oxide fuel cells (R-SOFCs) with chemically stable proton-conducting oxides

    KAUST Repository

    Bi, Lei

    2015-07-01

    Proton-conducting oxides offer a promising way of lowering the working temperature of solid oxide cells to the intermediate temperate range (500 to 700. °C) due to their better ionic conductivity. In addition, the application of proton-conducting oxides in both solid oxide fuel cells (SOFCs) and sold oxide electrolysis cells (SOECs) provides unique advantages compared with the use of conventional oxygen-ion conducting conductors, including the formation of water at the air electrode site. Since the discovery of proton conduction in some oxides about 30. years ago, the development of proton-conducting oxides in SOFCs and SOECs (the reverse mode of SOFCs) has gained increased attention. This paper briefly summarizes the development in the recent years of R-SOFCs with proton-conducting electrolytes, focusing on discussing the importance of adopting chemically stable materials in both fuel cell and electrolysis modes. The development of electrode materials for proton-conducting R-SOFCs is also discussed. © 2015 Elsevier B.V.

  13. Oxidant/Antioxidant Balance in Animal Nutrition and Health: The Role of Protein Oxidation.

    Science.gov (United States)

    Celi, Pietro; Gabai, Gianfranco

    2015-01-01

    This review examines the role that oxidative stress (OS), and protein oxidation in particular, plays in nutrition, metabolism, and health of farm animals. The route by which redox homeostasis is involved in some important physiological functions and the implications of the impairment of oxidative status on animal health and diseases is also examined. Proteins have various and, at the same time, unique biological functions and their oxidation can result in structural changes and various functional modifications. Protein oxidation seems to be involved in pathological conditions, such as respiratory diseases and parasitic infection; however, some studies also suggest that protein oxidation plays a crucial role in the regulation of important physiological functions, such as reproduction, nutrition, metabolism, lactation, gut health, and neonatal physiology. As the characterization of the mechanisms by which OS may influence metabolism and health is attracting considerable scientific interest, the aim of this review is to present veterinary scientists and clinicians with various aspects of oxidative damage to proteins.

  14. Copper-mediated oxidative degradation of catecholamines and oxidative damage of protein

    Energy Technology Data Exchange (ETDEWEB)

    Goncalves, P.R.; Harria, M.I.N.; Felix, J.M.; Hoffmann, M.E. [Universidade Estadual de Campinas, SP (Brazil). Inst. de Biologia

    1997-12-31

    Full text. Degradative oxidation of catecholamines has been a matter of large interest in recent years due to the evidences associating their autoxidation with the etiology of neurotoxic and cardiotoxic processes. In this work we present data on the degradative oxidation of catecholamines of physiological importance: isoproterenol (IP), epinephrine (EP), norepinephrine (NEP), deoxyepinephrine (DEP) and dopamine (DA). The degradative oxidation of the catecholamines was followed by measurement of spectral changes and oxygen consumption by neutral aqueous solutions. The data show that Cu{sup 2+} strongly accelerated the rate of catecholamine oxidation, following the decreasing order; EP>DEP>IP>NEP>DA. The production of superoxide anion radical during catecholamine oxidation was very slow, even in the presence of Cu{sup 2+}. The ability of IP to induce damages on bovine serum albumin (BSA) was determined by measuring the formation of carbonyl-groups in the protein, detected by reduction with tritiated Na BH{sub 4}. The incubation of BSA with IP (50-500{mu}M), in the presence of 100{mu}M Cu{sup 2+} leaded to an increased and dose dependent {sup 3} H-incorporation by the oxidized protein. The production of oxidative damage by IP/Cu{sup 2+} was accompanied by marked BSA fragmentation, detected by SDS-polyacrylamide gel dependent (25-400{mu}M IP) des appearance of the original BSA band and appearance of smaller fragments spread in the gel, when incubation has been done in the presence of 100{mu}M Cu{sup 2+}. These results suggest that copper-catalysed oxidative degradation of proteins induced by catecholamines might be critically involved in the toxic action of these molecules

  15. Catalytic activity of oxide cerium-molybdenum-tellurium catalysts in oxidation ammonolysis

    International Nuclear Information System (INIS)

    Dzhordano, N.; Bart, D.; Madzhori, R.

    1984-01-01

    A commercial catalyst containing a mixture of Ce-, Mo-, Te oxides deposited on SiO 2 is shown to manifest a high efficiency in oxidative ammonolysis of propylene (C 3 - ) to acrylonitrile (AN). The dependence of the catalytic properties on the catalyst composition and reaction conditions is studied. It is established that three-component mixtures are more active and selective than the systems with a lesser number of components. Using the catalyst with the optimum ratio of constituent oxides in a microreactor at 440 deg enabled one to achieve initial selectivity in terms of AN equal to 82.5% at 97% conversion of C 3 - . Acrolein, acetonitrile, HCN and nitrogen oxides are the reaction by-products. A supposition is made that the reaction proceeds via the formation of π-compleXes on the centres of Te(4). Setective oxidation occurs on oxygen atoms bonded with the Mo(6) ions. Tellurium enhances the molybdenum reducibleness due to delocalization of electrons, whereas the cerium addition to the mixture of tellurium- and molybdenum oxides increases the rate of molybdenum reoxidation and thus enhances the catalytic system stability

  16. PREFACE: Semiconducting oxides Semiconducting oxides

    Science.gov (United States)

    Catlow, Richard; Walsh, Aron

    2011-08-01

    Semiconducting oxides are amongst the most widely studied and topical materials in contemporary condensed matter science, with interest being driven both by the fundamental challenges posed by their electronic and magnetic structures and properties, and by the wide range of applications, including those in catalysis and electronic devices. This special section aims to highlight recent developments in the physics of these materials, and to show the link between developing fundamental understanding and key application areas of oxide semiconductors. Several aspects of the physics of this wide and expanding range of materials are explored in this special section. Transparent semiconducting oxides have a growing role in several technologies, but challenges remain in understanding their electronic structure and the physics of charge carriers. A related problem concerns the nature of redox processes and the reactions which interconvert defects and charge carriers—a key issue which may limit the extent to which doping strategies may be used to alter electronic properties. The magnetic structures of the materials pose several challenges, while surface structures and properties are vital in controlling catalytic properties, including photochemical processes. The field profits from and exploits a wide range of contemporary physical techniques—both experimental and theoretical. Indeed, the interplay between experiment and computation is a key aspect of contemporary work. A number of articles describe applications of computational methods whose use, especially in modelling properties of defects in these materials, has a long and successful history. Several papers in this special section relate to work presented at a symposium within the European Materials Research Society (EMRS) meeting held in Warsaw in September 2010, and we are grateful to the EMRS for supporting this symposium. We would also like to thank the editorial staff of Journal of Physics: Condensed Matter for

  17. Mechanism and Thermochemistry of Coal Char Oxidation and Desorption of Surface Oxides

    DEFF Research Database (Denmark)

    Levi, Gianluca; Causà, Mauro; Lacovig, Paolo

    2017-01-01

    The present study investigates the coal char combustion by a combination of thermochemical and X-ray photoemission spectroscopy (XPS) analyses. Thermoanalytical methods (differential thermogravimetry, differential scanning calorimetry, and temperature-programmed desorption) are used to identify...... the key reactive steps that occur upon oxidation and heating of coal char (chemisorption, structural rearrangement and switchover of surface oxides, and desorption) and their energetics. XPS is used to reveal the chemical nature of the surface oxides that populate the char surface and to monitor...... functionalities prevail. The rearrangement of epoxy during preoxidation goes together with activation of the more stable and less reactive carbon sites. Results are in good agreement with semi-lumped kinetic models of carbon oxidation, which include (1) formation of "metastable" surface oxides, (2) complex...

  18. Uranium oxidation: Characterization of oxides formed by reaction with water by infrared and sorption analyses

    Science.gov (United States)

    Fuller, E. L.; Smyrl, N. R.; Condon, J. B.; Eager, M. H.

    1984-04-01

    Three different uranium oxide samples have been characterized with respect to the different preparation techniques. The results show that the water reaction with uranium metal occurs cyclically forming laminar layers of oxide which spall off due to the strain at the oxide/metal interface. Single laminae are released if liquid water is present due to the prizing penetration at the reaction zone. The rate of reaction of water with uranium is directly proportional to the amount of adsorbed water on the oxide product. Rapid transport is effected through the open hydrous oxide product. Dehydration of the hydrous oxide irreversibly forms a more inert oxide which cannot be rehydrated to the degree that prevails in the original hydrous product of uranium oxidation with water. Inert gas sorption analyses and diffuse reflectance infrared studies combined with electron microscopy prove valuable in defining the chemistry and morphology of the oxidic products and hydrated intermediates.

  19. Rare earth oxide doping in oxide cathodes

    International Nuclear Information System (INIS)

    Engelsen, Daniel den; Gaertner, Georg

    2006-01-01

    The effect on life performance and poisoning with O 2 by doping oxide cathodes with rare earth oxides and pseudo rare earth oxides, notably yttria, is qualitatively explained in terms of electrolysis of BaO during emission of electrons. Doped cathodes show less electrolysis and consume therefore less Ba during life: consequently, doped cathodes have a better life performance. However, the lower Ba-production makes doped cathodes more sensitive to oxygen poisoning. The experimentally found relation between conductivity and yttria concentration was the motive to propose a new model for the crystal imperfections in BaO. In this new imperfection model most Y 3+ -ions will combine with barium vacancies, therefore, the increase of the conductivity is modest and also the effect on the position of the Fermi level is modest. By assuming a combination of bulk and surface conductivity, the agreement between experiment and theory can be improved further

  20. Effects of stress on the oxide layer thickness and post-oxidation creep strain of zircaloy-4

    International Nuclear Information System (INIS)

    Lim, Sang Ho; Yoon, Young Ku

    1986-01-01

    Effects of compressive stress generated in the oxide layer and its subsequent relief on oxidation rate and post-oxidation creep characteristics of zircaloy-4 were investigated by oxidation studies in steam with and without applied tensile stress and by creep testing at 700 deg C in high purity argon. The thickness of oxide layer increased with the magnitude of tensile stress applied during oxidation at 650 deg C in steam whereas similar phenomenon was not observed during oxidation at 800 deg C. Zircaloy-4 specimens oxidized at 600 deg C in steam without applied stress exhibited higher creep strain than that shown by unoxidized specimens when creep-tested in argon. Zircaloy-4 specimens oxidized at 600 deg C steam under the applied stress of 8.53MPa and oxidized at 800 deg C under the applied stress of 0 and 8.53MPa exhibited lower strain than that shown by unoxidized specimen. The above experimental results were accounted for on the basis of interactions among applied stress during oxidation, compressive stress generated in the oxide layer and elasticity of zircaloy-4 matrix. (Author)

  1. Effect of oxide ion concentration on the electrochemical oxidation of carbon in molten LiCl

    International Nuclear Information System (INIS)

    Yun, J. W.; Choi, I. K.; Park, Y. S.; Kim, W. H.

    2001-01-01

    The continuous measurement of lithium oxide concentration was required in DOR (Direct Oxide Reduction) process, which converts spent nuclear fuel to metal form, for the reactivity monitor and effective control of the process. The concentration of lithium oxide was measured by the electrochemical method, which was based on the phenomenon that carbon atoms of glassy carbon electrode electrochemically react with oxygen ions of lithium oxide in molten LiCl medium. From the results of electrode polarization experiments, the trend of oxidation rate of carbon atoms was classified into two different regions, which were proportional and non-proportional ones, dependent on the amount of lithium oxide. Below about 2.5 wt % Li 2 O, as the carbon atom ionization rate was fast enough for reacting with diffusing lithium oxide to the surface of carbon electrode. In this concentration range, the oxidation rate of carbon atoms was controlled by the diffusion of lithium oxide, and the concentration of lithium oxide could be measured by electrochemical method. But, above 2.5 wt % Li 2 O, the oxidation rate of carbon atoms was controlled by the applied electrochemical potential, because the carbon atom ionization rate was suppressed by the huge amounts of diffusing Li 2 O. Above this concentration, the electrochemical method was not applicable to determine the concentration of lithium oxide

  2. Characterization and uranium bioleaching performance of mixed iron- and sulfur-oxidizers versus iron-oxidizers

    International Nuclear Information System (INIS)

    Qian Li; Jing Sun; Dexin Ding; Qingliang Wang; Wenge Shi; Eming Hu; Xiaoyu Jiang; University of South China, Hengyang; Xingxing Wang

    2017-01-01

    In order to develop and apply mixed iron- and sulfur-oxidizers in uranium bioleaching, the characteristics of a mixed iron- and sulfur-oxidizing consortium (Consortium ISO) were comparatively investigated versus an iron-oxidizing consortium (Consortium IO). The results showed, the Consortium ISO exerted stronger oxidative ability and acid-producing ability than Consortium IO did. The synergy of sulfur-oxidizers and iron-oxidizers could change the structure and properties of the passivation substance, and work positively for eliminating the accumulation of passivation substance. In the bioleaching process, the uranium bioleaching experiments showed the recovery percentage of uranium reached 99.5% with Consortium ISO, 6.3% more than that of Consortium IO. (author)

  3. Thin zirconium oxides

    International Nuclear Information System (INIS)

    Oviedo, Cristina

    2000-01-01

    Polycrystalline Zr and two pure Zr single-crystal samples, one oriented with the normal to the surface parallel to the c-axis of the hcp structure (Z1) and the other with the normal perpendicular to c (Z2), were oxidised at 10 -8 , 10 -7 and 10 -6 Torr and room temperature. Oxidation kinetics, composition and thicknesses of the oxide films formed in each case were analyzed using XPS (X-ray Photoelectron Spectroscopy) as the main technique. The oxidation kinetics followed logarithmic laws in all cases. The deconvolution of XPS Zr3d peaks indicated the formation of two Zr-O compounds before the formation of ZrO 2 . Varying the photoelectrons take-off angle, the compound distribution inside the oxide films could be established. Thus, it was confirmed that the most external oxide, in contact with the gas, was ZrO 2 . The thickness of the films grown at the different pressures was determined. In the polycrystalline samples, thicknesses between 15 and 19 ± 2Angstroem were obtained for pressures between 10 -8 and 10 -6 Torr, in close coincidence with the determined ones for Z2. The thicknesses measured in Z1 were smaller, reaching 13 ± 2Angstroem for the oxidations performed at 10 -6 Torr. (author)

  4. Selection of a Commercial Anode Oxide Coating for Electro-oxidation of Cyanide

    Directory of Open Access Journals (Sweden)

    Lanza Marcos Roberto V.

    2002-01-01

    Full Text Available This paper presents a study of the performance of two commercial dimensionally stable anode (DSA® oxide coatings in the electrochemical process for cyanide oxidation. The coatings studied were 70TiO2/30RuO2 and 55Ta2O5/45IrO2, on Ti substrate. The efficiency of both materials in the electro-oxidation of free cyanide was compared using linear voltammetry and electrolysis at constant potential. The 70TiO2/30RuO2 electrode shows a better performance in the electro-oxidation of free cyanide.

  5. Staged membrane oxidation reactor system

    Science.gov (United States)

    Repasky, John Michael; Carolan, Michael Francis; Stein, VanEric Edward; Chen, Christopher Ming-Poh

    2012-09-11

    Ion transport membrane oxidation system comprising (a) two or more membrane oxidation stages, each stage comprising a reactant zone, an oxidant zone, one or more ion transport membranes separating the reactant zone from the oxidant zone, a reactant gas inlet region, a reactant gas outlet region, an oxidant gas inlet region, and an oxidant gas outlet region; (b) an interstage reactant gas flow path disposed between each pair of membrane oxidation stages and adapted to place the reactant gas outlet region of a first stage of the pair in flow communication with the reactant gas inlet region of a second stage of the pair; and (c) one or more reactant interstage feed gas lines, each line being in flow communication with any interstage reactant gas flow path or with the reactant zone of any membrane oxidation stage receiving interstage reactant gas.

  6. Global DNA methylation and oxidative stress biomarkers in workers exposed to metal oxide nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Liou, Saou-Hsing; Wu, Wei-Te; Liao, Hui-Yi [National Institute of Environmental Health Sciences, National Health Research Institutes, Zhunan, Miaoli County, Taiwan (China); Chen, Chao-Yu; Tsai, Cheng-Yen; Jung, Wei-Ting [Department of Chemistry, Fu Jen Catholic University, New Taipei City, Taiwan (China); Lee, Hui-Ling, E-mail: huilinglee3573@gmail.com [Department of Chemistry, Fu Jen Catholic University, New Taipei City, Taiwan (China)

    2017-06-05

    Highlights: • Global methylation and oxidative DNA damage levels in nanomaterial handling workers were assessed. • 8-isoprostane in exhaled breath condensate of workers exposed to nanoparticles was higher. • 8-OHdG was negatively correlated with global methylation. • Exposure to metal oxide nanoparticles may lead to global methylation and DNA oxidative damage. - Abstract: This is the first study to assess global methylation, oxidative DNA damage, and lipid peroxidation in workers with occupational exposure to metal oxide nanomaterials (NMs). Urinary and white blood cell (WBC) 8-hydroxydeoxyguanosine (8-OHdG), and exhaled breath condensate (EBC) 8-isoprostane were measured as oxidative stress biomarkers. WBC global methylation was measured as an epigenetic alteration. Exposure to TiO{sub 2}, SiO{sub 2,} and indium tin oxide (ITO) resulted in significantly higher oxidative biomarkers such as urinary 8-OHdG and EBC 8-isoprostane. However, significantly higher WBC 8-OHdG and lower global methylation were only observed in ITO handling workers. Significant positive correlations were noted between WBC and urinary 8-OHdG (Spearman correlation r = 0.256, p = 0.003). Furthermore, a significant negative correlation was found between WBC 8-OHdG and global methylation (r = −0.272, p = 0.002). These results suggest that exposure to metal oxide NMs may lead to global methylation, DNA oxidative damage, and lipid peroxidation.

  7. Oxide ultrathin films science and technology

    CERN Document Server

    Pacchioni, Gianfranco

    2012-01-01

    A wealth of information in one accessible book. Written by international experts from multidisciplinary fields, this in-depth exploration of oxide ultrathin films covers all aspects of these systems, starting with preparation and characterization, and going on to geometrical and electronic structure, as well as applications in current and future systems and devices. From the Contents: Synthesis and Preparation of Oxide Ultrathin Films Characterization Tools of Oxide Ultrathin Films Ordered Oxide Nanostructures on Metal Surfaces Unusual Properties of Oxides and Other Insulators in the Ultrathin Limit Silica and High-K Dielectrics Thin Films in Microelectronics Oxide Passive Films and Corrosion Protection Oxide Films as Catalytic Materials and as Models of Real Catalysts Oxide Films in Spintronics Oxide Ultrathin Films in Solid Oxide Fuel Cells Transparent Conducting and Chromogenic Oxide Films as Solar Energy Materials Oxide Ultrathin Films in Sensor Applications Ferroelectricity in Ultrathin Film Capacitors T...

  8. METAL OXIDE NANOPARTICLES

    Energy Technology Data Exchange (ETDEWEB)

    FERNANDEZ-GARCIA,M.; RODGRIGUEZ, J.A.

    2007-10-01

    This chapter covers the fundamental science, synthesis, characterization, physicochemical properties and applications of oxide nanomaterials. Explains fundamental aspects that determine the growth and behavior of these systems, briefly examines synthetic procedures using bottom-up and top-down fabrication technologies, discusses the sophisticated experimental techniques and state of the art theory results used to characterize the physico-chemical properties of oxide solids and describe the current knowledge concerning key oxide materials with important technological applications.

  9. Improving Thermo-Oxidative Stability of Nitrile Rubber Composites by Functional Graphene Oxide

    Directory of Open Access Journals (Sweden)

    Rui Zhong

    2018-05-01

    Full Text Available Graphene oxide (GO, modified with anti-aging agent p-phenylenediamine (PPD, was added into nitrile rubber (NBR in order to improve the thermo-oxidative stability of NBR. The modification of GO and the transformation of functional groups were characterized by Fourier transform infrared spectroscopy (FTIR, Raman, and X-ray diffraction (XRD. Mechanical performances of NBR composites before and after the thermo-oxidative aging were recorded. The results of dynamic mechanical analysis (DMA show an increased storage modulus (G’ and a decreased value of area of tan δ peak after introducing modified GO into NBR. It indicates that filler particles show positive interaction with molecular chains. The thermo-oxidative stability of composites was investigated by thermogravimetric analysis (TG and differential scanning calorimetry (DSC. Then, the thermo-oxidative aging kinetic parameters were obtained by the Flynn–Wall–Ozawa (FWO equation. The results of aging tests show that the thermo-oxidative stability of rubber matrix increases obviously after introducing GO–PPD. In addition, mechanical properties (tensile strength and elongation at break of both before and after aged NBR/GO–PPD composites were superior to that of NBR. This work provides meaningful guidance for achieving multifunction thermo-oxidative aging resistance rubber composites.

  10. On the Design of Oxide Films, Nanomaterials, and Heterostructures for Solar Water Oxidation Photoanodes

    Science.gov (United States)

    Kronawitter, Coleman Xaver

    Photoelectrochemistry and its associated technologies show unique potential to facilitate the large-scale production of solar fuels—those energy-rich chemicals obtained through conversion processes driven by solar energy, mimicking the photosynthetic process of green plants. The critical component of photoelectrochemical devices designed for this purpose is the semiconductor photoelectrode, which must be optically absorptive, chemically stable, and possess the required electronic band alignment with respect to the redox couple of the electrolyte to drive the relevant electrochemical reactions. After many decades of investigation, the primary technological obstacle remains the development of photoelectrode structures capable of efficient and stable conversion of light with visible frequencies, which is abundant in the solar spectrum. Metal oxides represent one of the few material classes that can be made photoactive and remain stable to perform the required functions. The unique range of functional properties of oxides, and especially the oxides of transition metals, relates to their associated diversity of cation oxidation states, cation electronic configurations, and crystal structures. In this dissertation, the use of metal oxide films, nanomaterials, and heterostructures in photoelectrodes enabling the solar-driven oxidation of water and generation of hydrogen fuel is examined. A range of transition- and post-transition-metal oxide material systems and nanoscale architectures is presented. The first chapters present results related to electrodes based on alpha-phase iron(III) oxide, a promising visible-light-active material widely investigated for this application. Studies of porous films fabricated by physical vapor deposition reveal the importance of structural quality, as determined by the deposition substrate temperature, on photoelectrochemical performance. Heterostructures with nanoscale feature dimensionality are explored and reviewed in a later chapter

  11. The fate of arsenic adsorbed on iron oxides in the presence of arsenite-oxidizing bacteria.

    Science.gov (United States)

    Zhang, Zhennan; Yin, Naiyi; Du, Huili; Cai, Xiaolin; Cui, Yanshan

    2016-05-01

    Arsenic (As) is a redox-active metalloid whose toxicity and mobility in soil depend on its oxidation state. Arsenite [As(III)] can be oxidized by microbes and adsorbed by minerals in the soil. However, the combined effects of these abiotic and biotic processes are not well understood. In this study, the fate of arsenic in the presence of an isolated As(III)-oxidizing bacterium (Pseudomonas sp. HN-1, 10(9) colony-forming units (CFUs)·ml(-1)) and three iron oxides (goethite, hematite, and magnetite at 1.6 g L(-1)) was determined using batch experiments. The total As adsorption by iron oxides was lower with bacteria present and was higher with iron oxides alone. The total As adsorption decreased by 78.6%, 36.0% and 79.7% for goethite, hematite and magnetite, respectively, due to the presence of bacteria. As(III) adsorbed on iron oxides could also be oxidized by Pseudomonas sp. HN-1, but the oxidation rate (1.3 μmol h(-1)) was much slower than the rate in the aqueous phase (96.2 μmol h(-1)). Therefore, the results of other studies with minerals only might overestimate the adsorptive capacity of solids in natural systems; the presence of minerals might hinder As(III) oxidation by microbes. Under aerobic conditions, in the presence of iron oxides and As(III)-oxidizing bacteria, arsenic is adsorbed onto iron oxides within the adsorption capacity, and As(V) is the primary form in the solid and aqueous phases. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Mechanisms of electrochemical reduction and oxidation of nitric oxide

    NARCIS (Netherlands)

    Vooys, de A.C.A.; Beltramo, G.L.; Riet, van B.; Veen, van J.A.R.; Koper, M.T.M.

    2004-01-01

    A summary is given of recent work on the reactivity of nitric oxide on various metal electrodes. The significant differences between the reactivity of adsorbed NO and NO in solution are pointed out, both for the reduction and the oxidation reaction(s). Whereas adsorbed NO can be reduced only to

  13. Oxidation-resistant cermet

    Science.gov (United States)

    Phillips, W. M.

    1977-01-01

    Chromium metal alloys and chromium oxide ceramic are combined to produce cermets with oxidation-resistant properties. Application of cermets includes use in hot corrosive environments requiring strong resistive materials.

  14. Development of hierarchically porous cobalt oxide for enhanced photo-oxidation of indoor pollutants

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, J. P., E-mail: chengjp@zju.edu.cn [Zhejiang University, State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering (China); Shereef, Anas; Gray, Kimberly A., E-mail: k-gray@northwestern.edu [Northwestern University, Center for Catalysis and Surface Science (United States); Wu, Jinsong [Northwestern University, Department of Materials Science and Engineering (United States)

    2015-03-15

    Porous cobalt oxide was successfully prepared by precipitation of cobalt hydroxide followed by low temperature thermal decomposition. The morphologies of the resultant oxides remained as the corresponding hydroxides, although the morphology of cobalt hydroxides was greatly influenced by the precursor salts. The cobalt oxides with average crystal size less than 20 nm were characterized by X-ray diffraction, scanning electron microscope, BET surface area, and XPS analysis. The photocatalytic activities of the various cobalt oxides morphologies were investigated by comparing the photo-degradation of acetaldehyde under simulated solar illumination. Relative to their low order structures and reference titania samples, the hierarchical nanostructures of cobalt oxide showed excellent abilities to rapidly degrade acetaldehyde, a model air pollutant. This was attributed to the unique nature of these hierarchical cobalt oxide nanoassemblies, which contained many catalytically active reaction sites and open pores.

  15. Dissolving method for nuclear fuel oxide

    International Nuclear Information System (INIS)

    Tomiyasu, Hiroshi; Kataoka, Makoto; Asano, Yuichiro; Hasegawa, Shin-ichi; Takashima, Yoichi; Ikeda, Yasuhisa.

    1996-01-01

    In a method of dissolving oxides of nuclear fuels in an aqueous acid solution, the oxides of the nuclear fuels are dissolved in a state where an oxidizing agent other than the acid is present together in the aqueous acid solution. If chlorate ions (ClO 3 - ) are present together in the aqueous acid solution, the chlorate ions act as a strong oxidizing agent and dissolve nuclear fuels such as UO 2 by oxidation. In addition, a Ce compound which generates Ce(IV) by oxidation is added to the aqueous acid solution, and an ozone (O 3 ) gas is blown thereto to dissolve the oxides of nuclear fuels. Further, the oxides of nuclear fuels are oxidized in a state where ClO 2 is present together in the aqueous acid solution to dissolve the oxides of nuclear fuels. Since oxides of the nuclear fuels are dissolved in a state where the oxidizing agent is present together as described above, the oxides of nuclear fuels can be dissolved even at a room temperature, thereby enabling to use a material such as polytetrafluoroethylene and to dissolve the oxides of nuclear fuels at a reduced cost for dissolution. (T.M.)

  16. Direct oxide reducing method

    International Nuclear Information System (INIS)

    Tokiwai, Moriyasu.

    1995-01-01

    Calcium oxides and magnetic oxides as wastes generated upon direct reduction are subjected to molten salt electrolysis, and reduced metallic calcium and magnesium are separated and recovered. Then calcium and magnesium are used recyclically as the reducing agent upon conducting direct oxide reduction. Even calcium oxides and magnesium oxides, which have high melting points and difficult to be melted usually, can be melted in molten salts of mixed fluorides or chlorides by molten-salt electrolysis. Oxides are decomposed by electrolysis, and oxygen is removed in the form of carbon monoxide, while the reduced metallic calcium and magnesium rise above the molten salts on the side of a cathode, and then separated. Since only carbon monoxide is generated as radioactive wastes upon molten salt electrolysis, the amount of radioactive wastes can be greatly reduced, and the amount of the reducing agent used can also be decreased remarkably. (N.H.)

  17. What preschool children do and do not do with ungrammatical word orders

    OpenAIRE

    Abbot-Smith, Kirsten; Lieven, Elena; Tomasello, Michael

    2001-01-01

    Akhtar [J. Child Lang. 26 (1999) 339.] found that when 4-year-old English-speaking children hear novel verbs in transitive utterances with ungrammatical word orders (e.g., Elmo the tree meeked), they correct them to canonical SVO order almost all of the time. However, when 3-year-olds and older 2-year-olds hear these same utterances, they waver between correcting and using the ungrammatical ordering. In the current study, we adapted this task for children at 2;4, using an intransitive constru...

  18. Oxidation of pyrite: Consequences and significance

    Directory of Open Access Journals (Sweden)

    Dimitrijević Mile D.

    2002-01-01

    Full Text Available This paper presents the most important studies on the oxidation of pyrite particularly in aqueous solutions. The consequences of pyrite oxidation was examined, as well as its importance, from both the technical-technological and environmental points of view. The oxidation of pyrite was considered in two parts. The spontaneous oxidation of pyrite in nature was described in the first part, with this part comprising pyrite oxidation in deposits depots and mines. It is explained how way natural electrochemical processes lead to the decomposition of pyrite and other minerals associated with pyrite. The oxidation of pyrite occurring during technological processes such as grinding, flotation and leaching, was shown in the second part. Particular emphasis was placed on the oxidation of pyrite during leaching. This part includes the leaching of sulphide and oxide ores, the leaching of pyrite coal and the leaching of refractory gold-bearing ores (pressure oxidation, bacterial oxidation, oxidation by means of strong oxidants and the electrolysis of pyrite suspensions. Various mechanisms of pyrite oxidation and of the galvanic interaction of pyrite with other sulphide minerals are shown.

  19. Oxidant/Antioxidant Balance in Animal Nutrition and Health: The Role of Protein Oxidation

    OpenAIRE

    Celi, Pietro; Gabai, Gianfranco

    2015-01-01

    This review examines the role that oxidative stress (OS), and protein oxidation in particular, plays in nutrition, metabolism, and health of farm animals. The route by which redox homeostasis is involved in some important physiological functions and the implications of the impairment of oxidative status on animal health and diseases is also examined. Proteins have various and, at the same time, unique biological functions and their oxidation can result in structural changes and various functi...

  20. Oxidant/antioxidant balance in animal nutrition and health: the role of protein oxidation

    OpenAIRE

    Pietro eCeli; Pietro eCeli; Gianfranco eGabai

    2015-01-01

    This review examines the role that oxidative stress, and protein oxidation in particular, plays in nutrition, metabolism and health of farm animals. The route by which redox homeostasis is involved in some important physiological functions and the implications of the impairment of oxidative status on animal health and diseases is also examined. Proteins have various and, at the same time, unique biological functions and their oxidation can result in structural changes and various functional m...

  1. Does oxidative stress shorten telomeres?

    NARCIS (Netherlands)

    Boonekamp, Jelle J.; Bauch, Christina; Mulder, Ellis; Verhulst, Simon

    Oxidative stress shortens telomeres in cell culture, but whether oxidative stress explains variation in telomere shortening in vivo at physiological oxidative stress levels is not well known. We therefore tested for correlations between six oxidative stress markers and telomere attrition in nestling

  2. Wet-cupping removes oxidants and decreases oxidative stress.

    Science.gov (United States)

    Tagil, Suleyman Murat; Celik, Huseyin Tugrul; Ciftci, Sefa; Kazanci, Fatmanur Hacievliyagil; Arslan, Muzeyyen; Erdamar, Nazan; Kesik, Yunus; Erdamar, Husamettin; Dane, Senol

    2014-12-01

    Wet-cupping therapy is one of the oldest known medical techniques. Although it is widely used in various conditions such as acute\\chronic inflammation, infectious diseases, and immune system disorders, its mechanism of action is not fully known. In this study, we investigated the oxidative status as the first step to elucidate possible mechanisms of action of wet cupping. Wet cupping therapy is implemented to 31 healthy volunteers. Venous blood samples and Wet cupping blood samples were taken concurrently. Serum nitricoxide, malondialdehyde levels and activity of superoxide dismutase and myeloperoxidase were measured spectrophotometrically. Wet cupping blood had higher activity of myeloperoxidase, lower activity of superoxide dismutase, higher levels of malondialdehyde and nitricoxide compared to the venous blood. Wet cupping removes oxidants and decreases oxidative stress. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Fiber type-specific nitric oxide protects oxidative myofibers against cachectic stimuli.

    Directory of Open Access Journals (Sweden)

    Zengli Yu

    2008-05-01

    Full Text Available Oxidative skeletal muscles are more resistant than glycolytic muscles to cachexia caused by chronic heart failure and other chronic diseases. The molecular mechanism for the protection associated with oxidative phenotype remains elusive. We hypothesized that differences in reactive oxygen species (ROS and nitric oxide (NO determine the fiber type susceptibility. Here, we show that intraperitoneal injection of endotoxin (lipopolysaccharide, LPS in mice resulted in higher level of ROS and greater expression of muscle-specific E3 ubiqitin ligases, muscle atrophy F-box (MAFbx/atrogin-1 and muscle RING finger-1 (MuRF1, in glycolytic white vastus lateralis muscle than in oxidative soleus muscle. By contrast, NO production, inducible NO synthase (iNos and antioxidant gene expression were greatly enhanced in oxidative, but not in glycolytic muscles, suggesting that NO mediates protection against muscle wasting. NO donors enhanced iNos and antioxidant gene expression and blocked cytokine/endotoxin-induced MAFbx/atrogin-1 expression in cultured myoblasts and in skeletal muscle in vivo. Our studies reveal a novel protective mechanism in oxidative myofibers mediated by enhanced iNos and antioxidant gene expression and suggest a significant value of enhanced NO signaling as a new therapeutic strategy for cachexia.

  4. Trends for Methane Oxidation at Solid Oxide Fuel Cell Conditions

    DEFF Research Database (Denmark)

    Kleis, Jesper; Jones, Glenn; Abild-Pedersen, Frank

    2009-01-01

    First-principles calculations are used to predict a plausible reaction pathway for the methane oxidation reaction. In turn, this pathway is used to obtain trends in methane oxidation activity at solid oxide fuel cell (SOFC) anode materials. Reaction energetics and barriers for the elementary...... the Ni surfaces to other metals of interest. This allows the reactivity over the different metals to be understood in terms of two reactivity descriptors, namely, the carbon and oxygen adsorption energies. By combining a simple free-energy analysis with microkinetic modeling, activity landscapes of anode...

  5. Low Temperature Processed Complementary Metal Oxide Semiconductor (CMOS) Device by Oxidation Effect from Capping Layer

    KAUST Repository

    Wang, Zhenwei

    2015-04-20

    In this report, both p- and n-type tin oxide thin-film transistors (TFTs) were simultaneously achieved using single-step deposition of the tin oxide channel layer. The tuning of charge carrier polarity in the tin oxide channel is achieved by selectively depositing a copper oxide capping layer on top of tin oxide, which serves as an oxygen source, providing additional oxygen to form an n-type tin dioxide phase. The oxidation process can be realized by annealing at temperature as low as 190°C in air, which is significantly lower than the temperature generally required to form tin dioxide. Based on this approach, CMOS inverters based entirely on tin oxide TFTs were fabricated. Our method provides a solution to lower the process temperature for tin dioxide phase, which facilitates the application of this transparent oxide semiconductor in emerging electronic devices field.

  6. Insulating gallium oxide layer produced by thermal oxidation of gallium-polar GaN: Insulating gallium oxide layer produced by thermal oxidation of gallium-polar GaN

    Energy Technology Data Exchange (ETDEWEB)

    Hossain, T. [Kansas State Univ., Manhattan, KS (United States); Wei, D. [Kansas State Univ., Manhattan, KS (United States); Nepal, N. [Naval Research Lab. (NRL), Washington, DC (United States); Garces, N. Y. [Naval Research Lab. (NRL), Washington, DC (United States); Hite, J. K. [Naval Research Lab. (NRL), Washington, DC (United States); Meyer, H. M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Eddy, C. R. [Naval Research Lab. (NRL), Washington, DC (United States); Baker, Troy [Nitride Solutions, Wichita, KS (United States); Mayo, Ashley [Nitride Solutions, Wichita, KS (United States); Schmitt, Jason [Nitride Solutions, Wichita, KS (United States); Edgar, J. H. [Kansas State Univ., Manhattan, KS (United States)

    2014-02-24

    We report the benefits of dry oxidation of n -GaN for the fabrication of metal-oxide-semiconductor structures. GaN thin films grown on sapphire by MOCVD were thermally oxidized for 30, 45 and 60 minutes in a pure oxygen atmosphere at 850 °C to produce thin, smooth GaOx layers. Moreover, the GaN sample oxidized for 30 minutes had the best properties. Its surface roughness (0.595 nm) as measured by atomic force microscopy (AFM) was the lowest. Capacitance-voltage measurements showed it had the best saturation in accumulation region and the sharpest transition from accumulation to depletion regions. Under gate voltage sweep, capacitance-voltage hysteresis was completely absent. The interface trap density was minimum (Dit = 2.75×1010 cm–2eV–1) for sample oxidized for 30 mins. These results demonstrate a high quality GaOx layer is beneficial for GaN MOSFETs.

  7. Selective oxidation

    International Nuclear Information System (INIS)

    Cortes Henao, Luis F.; Castro F, Carlos A.

    2000-01-01

    It is presented a revision and discussion about the characteristics and factors that relate activity and selectivity in the catalytic and not catalytic partial oxidation of methane and the effect of variables as the temperature, pressure and others in the methane conversion to methanol. It thinks about the zeolites use modified for the catalytic oxidation of natural gas

  8. Inhibiting mitochondrial β-oxidation selectively reduces levels of nonenzymatic oxidative polyunsaturated fatty acid metabolites in the brain.

    Science.gov (United States)

    Chen, Chuck T; Trépanier, Marc-Olivier; Hopperton, Kathryn E; Domenichiello, Anthony F; Masoodi, Mojgan; Bazinet, Richard P

    2014-03-01

    Schönfeld and Reiser recently hypothesized that fatty acid β-oxidation is a source of oxidative stress in the brain. To test this hypothesis, we inhibited brain mitochondrial β-oxidation with methyl palmoxirate (MEP) and measured oxidative polyunsaturated fatty acid (PUFA) metabolites in the rat brain. Upon MEP treatment, levels of several nonenzymatic auto-oxidative PUFA metabolites were reduced with few effects on enzymatically derived metabolites. Our finding confirms the hypothesis that reduced fatty acid β-oxidation decreases oxidative stress in the brain and β-oxidation inhibitors may be a novel therapeutic approach for brain disorders associated with oxidative stress.

  9. Oxidation effect on templating of metal oxide nanoparticles within block copolymers

    International Nuclear Information System (INIS)

    Akcora, Pinar; Briber, Robert M.; Kofinas, Peter

    2009-01-01

    Amphiphilic norbornene-b-(norbornene dicarboxylic acid) diblock copolymers with different block ratios were prepared as templates for the incorporation of iron ions using an ion exchange protocol. The disordered arrangement of iron oxide particles within these copolymers was attributed to the oxidation of the iron ions and the strong interactions between iron oxide nanoparticles, particularly at high iron ion concentrations, which was found to affect the self-assembly of the block copolymer morphologies.

  10. The oxidation of acid azo dye AY 36 by a manganese oxide containing mine waste

    International Nuclear Information System (INIS)

    Clarke, Catherine E.; Kielar, Filip; Johnson, Karen L.

    2013-01-01

    Highlights: ► This study looks at the oxidative breakdown of the amine containing dye acid yellow 36 by a Mn oxide containing mine waste. ► The oxidation proceeds by successive one electron transfers between the dye molecule and the Mn oxide minerals. ► The initial decolorization of the dye is rapid, but does not involve the cleavage of the azo bond. -- Abstract: The oxidative breakdown of acid azo dye acid yellow 36 (AY 36) by a Mn oxide containing mine tailings is demonstrated. The oxidation reaction is pH dependent with the rate of decolorization increasing with decreasing pH. The oxidation reaction mechanism is initiated at the amino moiety and proceeds via successive, one electron transfers from the dye to the Mn oxide minerals. The reaction pathway involves the formation of a number of colorless intermediate products, some of which hydrolyze in a Mn oxide-independent step. Decolorization of the dye is rapid and is observed before the cleavage of the azo-bond, which is a slower process. The terminal oxidation products were observed to be p-benzoquinone and 3-hydroxybenzenesulfonate. The reaction order of the initial decolorization was determined to be pseudo fractional order with respect to pH and pseudo first order with respect to dye concentration and Mn tailings’ surface area

  11. Oxidation of tritium by hopcalite bed

    Energy Technology Data Exchange (ETDEWEB)

    Nishikawa, Masabumi; Shinnai, Kohsuke; Matsunaga, Sohichi; Kinoshita, Yoshihiko

    1984-08-01

    Oxidation by the catalyst bed with a metal oxide and subsequent adsorption to the porous dehydrative reagents is supposed to be effective process for scavenging tritium from an inert atmosphere. Use of spongy copper oxide or wires of copper oxide is not recommended to use as the metal oxide catalyst from the view point of mass transfer because of sintering and of limited effective surface area. Use of hopcalites and copper oxide-kieselguhr are examined in this study and it is concluded that hopcalites are more suitable as the metal oxide catalyst because they not only remain the oxidation power on hydrogen isotopes even at an ambient temperature, but also show a negligible drop in oxidation performances with repeated regeneration. The effective temperature is about 400/sup 0/C for hopcalites and 300-600/sup 0/C for copper oxide-kieselguhr to use as the oxidation bed of tritium.

  12. Oxidation of tritium by hopcalite bed

    International Nuclear Information System (INIS)

    Nishikawa, Masabumi; Shinnai, Kohsuke; Matsunaga, Sohichi; Kinoshita, Yoshihiko

    1984-01-01

    Oxidation by the catalyst bed with a metal oxide and subsequent adsorption to the porous dehydrative reagents is supposed to be effective process for scavenging tritium from an inert atmosphere. Use of spongy copper oxide or wires of copper oxide is not recommended to use as the metal oxide catalyst from the view point of mass transfer because of sintering and of limited effective surface area. Use of hopcalites and copper oxide-kieselguhr are examined in this study and it is concluded that hopcalites are more suitable as the metal oxide catalyst because they not only remain the oxidation power on hydrogen isotopes even at an ambient temperature, but also show a negligible drop in oxidation performances with repeated regeneration. The effective temperature is about 400 0 C for hopcalites and 300--600 0 C for copper oxide-kieselguhr to use as the oxidation bed of tritium. (author)

  13. Method of producing homogeneous mixed metal oxides and metal--metal oxide mixtures

    International Nuclear Information System (INIS)

    Quinby, T.C.

    1978-01-01

    Metal powders, metal oxide powders, and mixtures thereof of controlled particle size are provided by reacting an aqueous solution containing dissolved metal values with excess urea. Upon heating, urea reacts with water from the solution to leave a molten urea solution containing the metal values. The molten urea solution is heated to above about 180 0 C, whereupon metal values precipitate homogeneously as a powder. The powder is reduced to metal or calcined to form oxide particles. One or more metal oxides in a mixture can be selectively reduced to produce metal particles or a mixture of metal and metal oxide particles

  14. Electro-catalytic oxidation of reactive Orange 107 using cerium doped oxides of Nd3+ nanoparticle

    International Nuclear Information System (INIS)

    Rajkumar, K.; Muthukumar, M.; Mangalaraja, R.V.

    2011-01-01

    A new rare earth doped cerium oxide powder was used as a catalyst to investigate the removal of colour and TOC from simulated wastewater of Reactive Orange 107. The electro oxidation process was carried out in the reactor in presence of an electrolyte NaCl. Graphite electrode was used as anode and cathode and electrolysis were carried out at a current density of 34.96 mAcm -2 with a catalyst concentration of 0.05g L -1 . In order to find the efficiency of nanocatalyst, experiments were also conducted without catalyst. From the experiment, it was found that complete colour removal was achieved on electrocatalytic oxidation as well as electro oxidation. When comparing the above processes, catalytic oxidation shows more efficient than electro oxidation. With respect to the degradation of the dye, catalytic oxidation shows more TOC removal than the oxidation taken place without catalyst. It infers that even though the electro-catalytic oxidation process achieves complete decolouration but it does not achieve complete mineralisation. The FTIR and GCMS studies confirmed the formation of by-products. (author)

  15. Method of producing homogeneous mixed metal oxides and metal-metal oxide mixtures

    International Nuclear Information System (INIS)

    Quinby, T.C.

    1980-01-01

    A method for preparing particulate metal or metal oxide of controlled partile size comprises contacting an an aqueous solution containing dissolved metal values with excess urea at a temperature sufficient to cause urea to react with water to provide a molten urea solution containing the metal values; heating the molten urea solution to cause the metal values to precipitate, forming a mixture containing precipitated metal values; heating the mixture containing precipitated metal values to evaporate volatile material leaving a dry powder containing said metal values. The dry powder can be calcined to provide particulate metal oxide or reduced to provide particulate metal. Oxide mixtures are provided when the aqueous solution contains values of more than one metal. Homogeneousmetal-metal oxide mistures for preparing cermets can be prepared by selectively reducing at least one of the metal oxides. (auth)

  16. Supported versus colloidal zinc oxide for advanced oxidation processes

    Science.gov (United States)

    Laxman, Karthik; Al Rashdi, Manal; Al Sabahi, Jamal; Al Abri, Mohammed; Dutta, Joydeep

    2017-07-01

    Photocatalysis is a green technology which typically utilizes either supported or colloidal catalysts for the mineralization of aqueous organic contaminants. Catalyst surface area and surface energy are the primary factors determining its efficiency, but correlation between the two is still unclear. This work explores their relation and hierarchy in a photocatalytic process involving both supported and colloidal catalysts. In order to do this the active surface areas of supported zinc oxide nanorods (ZnO NR's) and colloidal zinc oxide nanoparticles (having different surface energies) were equalized and their phenol oxidation mechanism and capacity was analyzed. It was observed that while surface energy had subtle effects on the oxidation rate of the catalysts, the degradation efficiency was primarily a function of the surface area; which makes it a better parameter for comparison when studying different catalyst forms of the same material. Thus we build a case for the use of supported catalysts, wherein their catalytic efficiency was tested to be unaltered over several days under both natural and artificial light, suggesting their viability for practical applications.

  17. Poly(ethylene oxide)–Poly(propylene oxide)-Based Copolymers for ...

    African Journals Online (AJOL)

    Amphiphilic poly(ethylene oxide)–poly(propylene oxide) (PEO–PPO)-based copolymers are thermoresponsive materials having aggregation properties in aqueous medium. As hydrosolubilizers of poorly water-soluble drugs and improved stability of sensitive agents, these materials have been investigated for improvement ...

  18. Effect of yttrium on the oxide scale adherence of pre-oxidized silicon-containing heat-resistant alloy

    International Nuclear Information System (INIS)

    Yan Jingbo; Gao Yimin; Shen Yudi; Yang Fang; Yi Dawei; Ye Zhaozhong; Liang Long; Du Yingqian

    2011-01-01

    Highlights: → AE experiment shows yttrium has a beneficial effect on the pre-oxidized HP40 alloy. → Yttrium facilitates the formation of internal oxide after 10 h of oxidation. → Internal oxide changes the rupture behaviour of the oxide scale. → Twins form in the internal oxide and improve the binding strength of the scale. - Abstract: This paper investigates the effect of the rare earth element yttrium on the rupture behaviour of the oxide scale on the silicon-containing heat-resistant alloy during cooling. After 10 h of oxidation, yttrium is found to facilitate the formation of internal oxides (silica) at the scale-matrix interface. Due to the twinning observed by scanning transmission electron microscopy (STEM) in silica, the critical strain value for the scale failure can be dramatically improved, and the formation of cracks at the scale-matrix interface is inhibited.

  19. Oxidative Weathering of Archean Sulfides: Implications for the Great Oxidation Event

    Science.gov (United States)

    Johnson, A.; Romaniello, S. J.; Reinhard, C.; Garcia-Robledo, E.; Revsbech, N. P.; Canfield, D. E.; Lyons, T. W.; Anbar, A. D.

    2015-12-01

    The first widely accepted evidence for oxidation of Earth's atmosphere and oceans occurs ~2.45 Ga immediately prior to the Great Oxidation Event (GOE). A major line of evidence for this transition includes the abundances and isotopic variations of redox-sensitive transition metals in marine sediments (e.g., Fe, Mo, Re, Cr, and U). It is often assumed that oxidative weathering is required to liberate these redox-sensitive elements from sulfide minerals in the crust, and hence that their presence in early Archean marine sediments signifies that oxidative weathering was stimulated by small and/or transient "whiffs" of O2 in the environment.1 However, studies of crustal sulfide reactivity have not been conducted at O2 concentrations as low as those that would have prevailed when O2 began its rise during the late Archean (estimated at molybdenite oxidation kinetics at the nanomolar O2 concentrations that are relevant to late Archean environments. These measurements were made using recently developed, highly sensitive optical O2 sensors to monitor the rates at which the powdered minerals consumed dissolved O2 in a range of pH-buffered solutions.3Our data extend the range of experimental pyrite oxidation rates in the literature by three orders of magnitude from ~10-3 present atmospheric O2 to ~10-6. We find that molybdenite and pyrite oxidation continues to <1 nM O2 (4 x 10-6 present atmospheric O2). This implies that oxidative weathering of sulfides could occur under conditions which preserve MIF S fractionation. Furthermore, our results indicate that the rate law and reaction order of pyrite oxidation kinetics change significantly at nanomolar concentrations of O2 when compared to previous compilations.2 Our results provide new empirical data that should allow for more precise quantitative constraints on atmospheric pO2 based on the sedimentary rock record. 1Anbar, A.D. et al., 2007. Science, 317, i. 5846: 1903-1906. 2Williamson & Rimstidt, 1994. Geochim. et Cosmochim

  20. Molecular theory of graphene oxide.

    Science.gov (United States)

    Sheka, Elena F; Popova, Nadezhda A

    2013-08-28

    Applied to graphene oxide, the molecular theory of graphene considers its oxide as a final product in the succession of polyderivatives related to a series of oxidation reactions involving different oxidants. The graphene oxide structure is created in the course of a stepwise computational synthesis of polyoxides of the (5,5) nanographene molecule governed by an algorithm that takes into account the molecule's natural radicalization due to the correlation of its odd electrons, the extremely strong influence of the structure on properties, and a sharp response of the molecule behavior on small actions of external factors. Taking these together, the theory has allowed for a clear, transparent and understandable explanation of the hot points of graphene oxide chemistry and suggesting reliable models of both chemically produced and chemically reduced graphene oxides.

  1. Characteristics of oxide scale formed on Cu-bearing austenitic stainless steel during early stages of high temperature oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Swaminathan, Srinivasan, E-mail: swaminathan@kist.re.kr [Metallurgy & Materials Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102 (India); High Temperature Energy Materials Research Center, Korea Institute of Science and Technology, Seongbuk-gu, Seoul 136 791 (Korea, Republic of); Krishna, Nanda Gopala [Metallurgy & Materials Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102 (India); Kim, Dong-Ik, E-mail: dongikkim@kist.re.kr [High Temperature Energy Materials Research Center, Korea Institute of Science and Technology, Seongbuk-gu, Seoul 136 791 (Korea, Republic of)

    2015-10-30

    Highlights: • Initial oxidation characteristics of Cu-bearing austenitic stainless steel at 650 °C were studied. • Strong segregation and oxidation of Mn and Nb were found in the entire oxide scale. • Surface coverage by metallic Cu-rich precipitates increases with exposure time. • Chemical heterogeneity of oxide scale revealed initial oxidation to be non-selective. • Fe-Cr and Mn-Cr mixed oxides were realized along with binary oxides of Fe, Cr and Mn. - Abstract: Oxide scale evolution on Cu-bearing austenitic stainless steel 304H at 650 °C, in ambient air, for exposure times 100, 300, 500 and 1000 h, has been investigated. Surface morphology and chemistry of the oxide scale grown were examined using SEM/EDX and XPS. The oxidation kinetics was determined by measuring the weight change using an electronic balance. At the initial stage, up to 500 h of exposure time, the oxidation rate was rapid due to surface reactions governed primarily by oxygen ingress, and then, dropped to a low rate after prolonged oxidation for 1000 h. The diffusion of reactants through the initially formed oxide scale limits the oxidation rate at longer times, thus, the progress of reaction followed the parabolic kinetics. The formed oxide scale was enriched significantly with segregation and subsequent oxidation of Nb, and finely dispersed metallic Cu particles. Within the time frame of oxidation, the oxide scale was mainly composed of mixed oxides such as FeCr{sub 2}O{sub 4} and MnCr{sub 2}O{sub 4} along with the binary oxides of Fe, Cr and Mn. Moreover, the precipitation fraction of Cu-rich particles on the oxide scale increased markedly with increase of exposure times. The chemical heterogeneity of oxide scale suggests that the oxidation occurred in a non-selective manner.

  2. A novel hydrogen oxidizer amidst the sulfur-oxidizing Thiomicrospira lineage

    Science.gov (United States)

    Hansen, Moritz; Perner, Mirjam

    2015-01-01

    Thiomicrospira species are ubiquitously found in various marine environments and appear particularly common in hydrothermal vent systems. Members of this lineage are commonly classified as sulfur-oxidizing chemolithoautotrophs. Although sequencing of Thiomicrospira crunogena's genome has revealed genes that encode enzymes for hydrogen uptake activity and for hydrogenase maturation and assembly, hydrogen uptake ability has so far not been reported for any Thiomicrospira species. We isolated a Thiomicrospira species (SP-41) from a deep sea hydrothermal vent and demonstrated that it can oxidize hydrogen. We show in vivo hydrogen consumption, hydrogen uptake activity in partially purified protein extracts and transcript abundance of hydrogenases during different growth stages. The ability of this strain to oxidize hydrogen opens up new perspectives with respect to the physiology of Thiomicrospira species that have been detected in hydrothermal vents and that have so far been exclusively associated with sulfur oxidation. PMID:25226028

  3. Fatty acid omega-oxidation as a rescue pathway for fatty acid oxidation disorders in humans

    NARCIS (Netherlands)

    Wanders, Ronald J. A.; Komen, Jasper; Kemp, Stephan

    2011-01-01

    Fatty acids (FAs) can be degraded via different mechanisms including alpha-, beta- and omega-oxidation. In humans, a range of different genetic diseases has been identified in which either mitochondrial FA beta-oxidation, peroxisomal FA beta-oxidation or FA alpha-oxidation is impaired. Treatment

  4. High Temperature Oxidation Behavior of Zirconium Alloy with Nano structured Oxide Layer in Air Environment

    International Nuclear Information System (INIS)

    Park, Y. J.; Kim, J. W.; Park, J. W.; Cho, S. O.

    2016-01-01

    If the temperature of the cladding materials increases above 1000 .deg. C, which can be caused by a loss of coolant accident (LOCA), Zr becomes an auto-oxidation catalyst and hence produces a huge amount of hydrogen gas from water. Therefore, many investigations are being carried out to prevent (or reduce) the hydrogen production from Zr-based cladding materials in the nuclear reactors. Our team has developed an anodization technique by which nanostructured oxide can be formed on various flat metallic elements such as Al, Ti, and Zr-based alloy. Anodization is a simple electrochemical technique and requires only a power supply and an electrolyte. In this study, Zr-based alloys with nanostructured oxide layers were oxidized by using Thermogravimetry analysis (TGA) and compared with the pristine one. It reveals that the nanostructured oxide layer can prevent oxidation of substrate metal in air. Oxidation behavior of the pristine Zr-Nb-Sn alloy and the Zr-Nb-Sn alloy with nanostructured oxide layer evaluated by measuring weight gain (TGA). In comparison with the pristine Zr-Nb-Sn alloy, weight gain of the Zr-Nb-Sn alloy with nanostructured oxide layer is lower than 10% even for 12 hours oxidation in air.

  5. Zinc oxide overdose

    Science.gov (United States)

    Zinc oxide is an ingredient in many products. Some of these are certain creams and ointments used ... prevent or treat minor skin burns and irritation. Zinc oxide overdose occurs when someone eats one of ...

  6. Facile synthesis of iron oxides/reduced graphene oxide composites: application for electromagnetic wave absorption at high temperature

    OpenAIRE

    Lili Zhang; Xinxin Yu; Hongrui Hu; Yang Li; Mingzai Wu; Zhongzhu Wang; Guang Li; Zhaoqi Sun; Changle Chen

    2015-01-01

    Iron oxides/reduced graphene oxide composites were synthesized by facile thermochemical reactions of graphite oxide and FeSO4?7H2O. By adjusting reaction temperature, ?-Fe2O3/reduced graphene oxide and Fe3O4/reduced graphene oxide composites can be obtained conveniently. Graphene oxide and reduced graphene oxide sheets were demonstrated to regulate the phase transition from ?-Fe2O3 to Fe3O4 via ?-Fe2O3, which was reported for the first time. The hydroxyl groups attached on the graphene oxide ...

  7. Synergistic effect of graphene oxide on the methanol oxidation for fuel cell application

    Science.gov (United States)

    Siwal, Samarjeet; Ghosh, Sarit; Nandi, Debkumar; Devi, Nishu; Perla, Venkata K.; Barik, Rasmita; Mallick, Kaushik

    2017-09-01

    Aromatic polypyrene was synthesized by the oxidative polymerization of pyrene with potassium tetrachloropalladate (II), as oxidant. During the polymerization process the palladium salt was reduced to metallic palladium and forms the metal-polymer composite material. Polypyrene stabilized palladium nanoparticles showed electrocatalytic activity toward the oxidation of methanol. The performance of the electrocatalytic activity was substantially improved with the incorporation of graphene oxide to the palladium-polypyrene composite and the synergistic performance was attributed to the electronic and structural properties of the system.

  8. W-containing oxide layers obtained on aluminum and titanium by PEO as catalysts in thiophene oxidation

    Science.gov (United States)

    Rudnev, V. S.; Lukiyanchuk, I. V.; Vasilyeva, M. S.; Morozova, V. P.; Zelikman, V. M.; Tarkhanova, I. G.

    2017-11-01

    W-containing oxide layers fabricated on titanium and aluminum alloys by Plasma electrolytic oxidation (PEO) have been tested in the reaction of the peroxide oxidation of thiophene. Samples with two types of coatings have been investigated. Coatings I contained tungsten oxide in the matrix and on the surface of amorphous silica-titania or silica-alumina layers, while coatings II comprised crystalline WO3 and/or Al2(WO4)3. Aluminum-supported catalyst containing a smallest amount of transition metals in the form of tungsten oxides and manganese oxides in low oxidation levels showed high activity and stability.

  9. Investigating the Grammatical and Pragmatic Origins of Wh-Questions in Children with Autism Spectrum Disorders

    Directory of Open Access Journals (Sweden)

    Manya Jyotishi

    2017-03-01

    Full Text Available Compared to typically developing children, children with autism (ASD show delayed production of wh-questions. It is currently controversial the degree to which such deficits derive from social-pragmatic requirements and/or because these are complex grammatical structures. The current study employed the intermodal preferential looking (IPL paradigm, which reduces social-pragmatic demands. The IPL paradigm can help distinguish these proposals, as successful comprehension promotes the “pragmatics-origins” argument whereas comprehension difficulties would implicate a “grammatical-origins” argument. Additionally, we tested both the linguistic and social explanations by assessing the contributions of children's early grammatical knowledge (i.e., SVO word order and their social-pragmatic scores on the Vineland to their later wh-question comprehension. Fourteen children with ASD and 17 TD children, matched on language level, were visited in their homes at 4-month intervals. Comprehension of wh-questions and SVO word order were tested via IPL: the wh-question video showed a costumed horse and bird serving as agents or patients of familiar transitive actions. During the test trials, they were displayed side by side with directing audios (e.g., “What did the horse tickle?”, “What hugged the bird?”, “Where is the horse/bird?”. Children's eye movements were coded offline; the DV was their percent looking to the named item during test. To show comprehension, children should look longer at the named item during a where-question than during a subject-wh or object-wh question. Results indicated that TD children comprehended both subject and object wh-questions at 32 months of age. Comprehension of object-wh questions emerged chronologically later in children with ASD compared to their TD peers, but at similar levels of language. Moreover, performance on word order and social-pragmatic scores independently predicted both groups' later

  10. Electrochemical Thinning for Anodic Aluminum Oxide and Anodic Titanium Oxide

    Energy Technology Data Exchange (ETDEWEB)

    Lee, In Hae; Jo, Yun Kyoung; Kim, Yong Tae; Tak, Yong Sug; Choi, Jin Sub [Inha University, Incheon (Korea, Republic of)

    2012-05-15

    For given electrolytes, different behaviors of anodic aluminum oxide (AAO) and anodic titanium oxide (ATO) during electrochemical thinning are explained by ionic and electronic current modes. Branched structures are unavoidably created in AAO since the switch of ionic to electronic current is slow, whereas the barrier oxide in ATO is thinned without formation of the branched structures. In addition, pore opening can be possible in ATO if chemical etching is performed after the thinning process. The thinning was optimized for complete pore opening in ATO and potential-current behavior is interpreted in terms of ionic current-electronic current switching.

  11. Molecular water oxidation catalysis

    CERN Document Server

    Llobet, Antoni

    2014-01-01

    Photocatalytic water splitting is a promising strategy for capturing energy from the sun by coupling light harvesting and the oxidation of water, in order to create clean hydrogen fuel. Thus a deep knowledge of the water oxidation catalysis field is essential to be able to come up with useful energy conversion devices based on sunlight and water splitting. Molecular Water Oxidation Catalysis: A Key Topic for New Sustainable Energy Conversion Schemes presents a comprehensive and state-of-the-art overview of water oxidation catalysis in homogeneous phase, describing in detail the most importan

  12. Relationships among oxidation-reduction and acid-base properties of the actinides in high oxidation states

    International Nuclear Information System (INIS)

    Morss, L.R.

    1992-01-01

    The first chemical identification of plutonium, its subsequent isolation on the macroscopic scale, and more recent chemical separation schemes were achieved by taking advantage of the differences among the oxidation states of uranium, neptunium, and plutonium. Many acid-base properties modify the relative stabilities of oxidation states of the actinides. In the solid state, strongly basic compounds such as Cs 2 O yield complex oxides with oxidation states of Np(VII), Pu(VI), and Am(VI) whereas more acidic compounds such as CsF yield complex fluorides with lower oxidation states. In aqueous solution, high basicity and strongly covalent complexes favor high oxidation states. In nonaqueous solvent systems, high acidity generally favors low oxidation states. This paper elucidates and attempts to interpret the effects of these acid-base properties in a systematic fashion

  13. Oxidation behaviour and electrical properties of cobalt/cerium oxide composite coatings for solid oxide fuel cell interconnects

    DEFF Research Database (Denmark)

    Harthøj, Anders; Holt, Tobias; Møller, Per

    2015-01-01

    This work evaluates the performance of cobalt/cerium oxide (Co/CeO2) composite coatings and pure Co coatings to be used for solid oxide fuel cell (SOFC) interconnects. The coatings are electroplated on the ferritic stainless steels Crofer 22 APU and Crofer 22H. Coated and uncoated samples...

  14. Oxidative phosphorylation revisited

    DEFF Research Database (Denmark)

    Nath, Sunil; Villadsen, John

    2015-01-01

    The fundamentals of oxidative phosphorylation and photophosphorylation are revisited. New experimental data on the involvement of succinate and malate anions respectively in oxidative phosphorylation and photophosphorylation are presented. These new data offer a novel molecular mechanistic...

  15. Oxidative Ce"3"+ sequestration by fungal manganese oxides with an associated Mn(II) oxidase activity

    International Nuclear Information System (INIS)

    Zheng, Haisu; Tani, Yukinori; Naitou, Hirotaka; Miyata, Naoyuki; Tojo, Fuyumi

    2016-01-01

    Sequestration of Ce"3"+ by biogenic manganese oxides (BMOs) formed by a Mn(II)-oxidizing fungus, Acremonium strictum strain KR21-2, was examined at pH 6.0. In anaerobic Ce"3"+ solution, newly formed BMOs exhibited stoichiometric Ce"3"+ oxidation, where the molar ratio of Ce"3"+ sequestered (Ce_s_e_q) relative to Mn"2"+ released (Mn_r_e_l) was maintained at approximately two throughout the reaction. A similar Ce"3"+ sequestration trend was observed in anaerobic treatment of BMOs in which the associated Mn(II) oxidase was completely inactivated by heating at 85 °C for 1 h or by adding 50 mM NaN_3. Aerobic Ce"3"+ treatment of newly formed BMO (enzymatically active) resulted in excessive Ce"3"+ sequestration over Mn"2"+ release, yielding Ce_s_e_q/Mn_r_e_l > 200, whereas heated or poisoned BMOs released a significant amount of Mn"2"+ with lower Ce"3"+ sequestration efficiency. Consequently, self-regeneration by the Mn(II) oxidase in newly formed BMO effectively suppressed Mn"2"+ release and enhanced oxidative Ce"3"+ sequestration under aerobic conditions. Repeated treatments of heated or poisoned BMOs under aerobic conditions confirmed that oxidative Ce"3"+ sequestration continued even after most Mn oxide was released from the solid phase, indicating auto-catalytic Ce"3"+ oxidation at the solid phase produced through primary Ce"3"+ oxidation by BMO. From X-ray diffraction analysis, the resultant solid phases formed through Ce"3"+ oxidation by BMO under both aerobic and anaerobic conditions consisted of cerianite with crystal sizes of 5.00–7.23 Å. Such nano-sized CeO_2 (CeO_2_,_B_M_O) showed faster auto-catalytic Ce"3"+ oxidation than that on well-crystalized cerianite under aerobic conditions, where the normalized pseudo-first order rate constants for auto-catalytic Ce"3"+ oxidation on CeO_2_,_B_M_O was two orders of magnitude higher. Consequently, we concluded that Ce"3"+ contact with BMOs sequesters Ce"3"+ through two oxidation paths: primary Ce"3

  16. The catalytic activity of several tungsten oxides for the oxidation of propene

    International Nuclear Information System (INIS)

    De Rossi, S.; Schiavello, M.; Rome Univ.; Iguchi, E.; Tilley, R.J.D.

    1976-01-01

    A study has been made of the catalytic oxidation of propene over the oxides WO 3 , WOsub(2,95), WOsub(2,90), WOsub(2,72) and Wo 2 , which were selected because they possess specific features of chemical and structural interest rather than for their catalytic ability. It was found that the oxides WOsub(2,95), WOsub(2,90) and WOsub(2,72) all selectively produce acrolein in small amounts. The oxides WO 3 and WO 2 were non-selective and rather inactive. The results are discussed in terms of a mechanism involving both variable valence in the crystal and the specific structural geometry of these compounds. (orig.) [de

  17. Oxidative Stress in BPH

    Directory of Open Access Journals (Sweden)

    Murat Savas

    2009-01-01

    The present study has shown that there were not relationship between potency of oxidative stress and BPH. Further well designed studies should be planned to find out whether the oxidative stress-related parameters play role in BPH as an interesting pathology in regard of the etiopathogenesis. Keywords: benign prostatic hyperplasia, oxidative stress, prostate

  18. Energetic basis of catalytic activity of layered nanophase calcium manganese oxides for water oxidation.

    Science.gov (United States)

    Birkner, Nancy; Nayeri, Sara; Pashaei, Babak; Najafpour, Mohammad Mahdi; Casey, William H; Navrotsky, Alexandra

    2013-05-28

    Previous measurements show that calcium manganese oxide nanoparticles are better water oxidation catalysts than binary manganese oxides (Mn3O4, Mn2O3, and MnO2). The probable reasons for such enhancement involve a combination of factors: The calcium manganese oxide materials have a layered structure with considerable thermodynamic stability and a high surface area, their low surface energy suggests relatively loose binding of H2O on the internal and external surfaces, and they possess mixed-valent manganese with internal oxidation enthalpy independent of the Mn(3+)/Mn(4+) ratio and much smaller in magnitude than the Mn2O3-MnO2 couple. These factors enhance catalytic ability by providing easy access for solutes and water to active sites and facile electron transfer between manganese in different oxidation states.

  19. Selective propene oxidation on mixed metal oxide catalysts

    International Nuclear Information System (INIS)

    James, David William

    2002-01-01

    Selective catalytic oxidation processes represent a large segment of the modern chemical industry and a major application of these is the selective partial oxidation of propene to produce acrolein. Mixed metal oxide catalysts are particularly effective in promoting this reaction, and the two primary candidates for the industrial process are based on iron antimonate and bismuth molybdate. Some debate exists in the literature regarding the operation of these materials and the roles of their catalytic components. In particular, iron antimonate catalysts containing excess antimony are known to be highly selective towards acrolein, and a variety of proposals for the enhanced selectivity of such materials have been given. The aim of this work was to provide a direct comparison between the behaviour of bismuth molybdate and iron antimonate catalysts, with additional emphasis being placed on the component single oxide phases of the latter. Studies were also extended to other antimonate-based catalysts, including cobalt antimonate and vanadium antimonate. Reactivity measurements were made using a continuous flow microreactor, which was used in conjunction with a variety of characterisation techniques to determine relationships between the catalytic behaviour and the properties of the materials. The ratio of Fe/Sb in the iron antimonate catalyst affects the reactivity of the system under steady state conditions, with additional iron beyond the stoichiometric value being detrimental to the acrolein selectivity, while extra antimony provides a means of enhancing the selectivity by decreasing acrolein combustion. Studies on the single antimony oxides of iron antimonate have shown a similarity between the reactivity of 'Sb 2 O 5 ' and FeSbO 4 , and a significant difference between these and the Sb 2 O 3 and Sb 2 O 4 phases, implying that the mixed oxide catalyst has a surface mainly comprised of Sb 5+ . The lack of reactivity of Sb 2 O 4 implies a similarity of the surface with

  20. Uranium Metal to Oxide Conversion by Air Oxidation –Process Development

    Energy Technology Data Exchange (ETDEWEB)

    Duncan, A

    2001-12-31

    Published technical information for the process of metal-to-oxide conversion of uranium components has been reviewed and summarized for the purpose of supporting critical decisions for new processes and facilities for the Y-12 National Security Complex. The science of uranium oxidation under low, intermediate, and high temperature conditions is reviewed. A process and system concept is outlined and process parameters identified for uranium oxide production rates. Recommendations for additional investigations to support a conceptual design of a new facility are outlined.

  1. Baltų kalbų žodžių tvarkos raida tipologijos požiūriu

    Directory of Open Access Journals (Sweden)

    Vytautas Ambrazas

    2011-12-01

    Full Text Available THE DEVELOPMENT OF WORD ORDER IN BALTIC FROM A TYPOLO­GICAL VIEWPOINTSummaryThe inherited word order type DH, in which dependent is placed before head, has been preserved up till now in most Lithuanian and Latvian word order patterns, e.g.: GenN, AdjN, DemN, AdvV, AdvAdj, AdvAdv1. Historical analysis reveals the former prevalence of DH order both in the distribution of main sentence components (SOV and in the comparative clauses (StComp. On the other hand, a tendency to place head before dependent manifests itself in the expansion of the SVO sentence pattern and of comparative clauses with a postposed standard (CompSt during the recent history of Lithuanian and Latvian.The early stage of HD order development in Baltic is represented by prepositional constructions. They are based on ancient clauses with preverbs, which modified the meaning of nouns and verbs and had the status of dependent components. Preverbs preceding verbs maintained their dependent status; they turned into verbal prefixes later. But preverbs preceding nouns changed their relation and became heads of prepositional constructions, i.e. prepositions governing cases.Reanalysis of preposed preverbs as prepositions caused a deviation from the prevailing word order type and paved the way to the use of HD patterns in other constructions. Contacts with Slavic languages stimulated this change. A relative chronology of expansion of some HD patterns in Baltic can be presented in the following sequence: Prep - CompSt - (SVO.

  2. Environmental constraints shaping constituent order in emerging communication systems: Structural iconicity, interactive alignment and conventionalization.

    Science.gov (United States)

    Christensen, Peer; Fusaroli, Riccardo; Tylén, Kristian

    2016-01-01

    Where does linguistic structure come from? Recent gesture elicitation studies have indicated that constituent order (corresponding to for instance subject-verb-object, or SVO in English) may be heavily influenced by human cognitive biases constraining gesture production and transmission. Here we explore the alternative hypothesis that syntactic patterns are motivated by multiple environmental and social-interactional constraints that are external to the cognitive domain. In three experiments, we systematically investigate different motivations for structure in the gestural communication of simple transitive events. The first experiment indicates that, if participants communicate about different types of events, manipulation events (e.g. someone throwing a cake) and construction events (e.g. someone baking a cake), they spontaneously and systematically produce different constituent orders, SOV and SVO respectively, thus following the principle of structural iconicity. The second experiment shows that participants' choice of constituent order is also reliably influenced by social-interactional forces of interactive alignment, that is, the tendency to re-use an interlocutor's previous choice of constituent order, thus potentially overriding affordances for iconicity. Lastly, the third experiment finds that the relative frequency distribution of referent event types motivates the stabilization and conventionalization of a single constituent order for the communication of different types of events. Together, our results demonstrate that constituent order in emerging gestural communication systems is shaped and stabilized in response to multiple external environmental and social factors: structural iconicity, interactive alignment and distributional frequency. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Dehydrogenation of Ethylbenzene with Carbon Dioxide as Soft Oxidant over Supported Vanadium-Antimony Oxide Catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Do Young; Vislovskiy, Vladislav P.; Yoo, Jin S.; Chang, Jong San [Korea Research Institute of Chemical Technology, Daejeon (Korea, Republic of); Park, Sang Eon [Inha University, Incheon (Korea, Republic of); Park, Min Seok [Mongolia International University, Ulaanbaatar (Mongolia)

    2005-11-15

    This work presents that carbon dioxide, which is a main contributor to the global warming effect, could be utilized as a selective oxidant in the oxidative dehydrogenation of ethylbenzene. The dehydrogenation of ethylbenzene over alumina-supported vanadium-antimony oxide catalyst has been studied under different atmospheres such as inert nitrogen, steam, oxygen or carbon dioxide as diluent or oxidant. Among them, the addition of carbon dioxide gave the highest styrene yield (up to 82%) and styrene selectivity (up to 97%) along with stable activity. Carbon dioxide could play a beneficial role of a selective oxidant in the improvement of the catalytic behavior through the oxidative pathway.

  4. Plutonium oxides and uranium and plutonium mixed oxides. Carbon determination

    International Nuclear Information System (INIS)

    Anon.

    Determination of carbon in plutonium oxides and uranium plutonium mixed oxides, suitable for a carbon content between 20 to 3000 ppm. The sample is roasted in oxygen at 1200 0 C, the carbon dioxide produced by combustion is neutralized by barium hydroxide generated automatically by coulometry [fr

  5. Electrochemistry of hydrous oxide films

    International Nuclear Information System (INIS)

    Burke, L.D.; Lyons, M.E.G.

    1986-01-01

    The formation, acid-base properties, structural aspects, and transport processes of hydrous oxide films are discussed. Classical and nonclassical theoretical models of the oxide-solution interface are compared. Monolayer oxidation, behavior, and crystal growth of oxides on platinum, palladium, gold, iridium, rhodium, ruthenium, and some non-noble metals, including tungsten, are reviewed and compared

  6. Selective oxidation of benzene and cyclohexane using amorphous microporous mixed oxides; Selektive Oxidation von Benzol und Cyclohexan mit amorphen mikroporoesen Mischoxiden

    Energy Technology Data Exchange (ETDEWEB)

    Stoeckmann, M.

    2000-07-01

    Phenol was to be produced by direct oxidation of benzene with environment-friendly oxidants like hydrogen peroxide, oxygen, or ozone. Catalysts were amorphous microporous mixed oxides whose properties can be selected directly in the sol-gel synthesis process. Apart from benzene, also cyclohexane was oxidized with ozone using AMM catalysts in order to get more information on the potential of ozone as oxidant in heterogeneously catalyzed reactions. [German] Ziel dieser Arbeit war die Herstellung von Phenol durch die Direktoxidation von Benzol mit umweltfreundlichen Oxidationsmitteln wie Wasserstoffperoxid, Sauerstoff oder Ozon. Als Katalysatoren dienten amorphe mikroporoese Mischoxide, da deren Eigenschaften direkt in der Synthese durch den Sol-Gel-Prozess gezielt eingestellt werden koennen. Neben Benzol wurde auch Cyclohexan mit Ozon unter der Verwendung von AMM-Katalysatoren oxidiert, um das Potential von Ozon als Oxiationsmittel in heterogen katalysierten Reaktionen naeher zu untersuchen. (orig.)

  7. Oxidative DNA damage and oxidative stress in lead-exposed workers.

    Science.gov (United States)

    Dobrakowski, M; Pawlas, N; Kasperczyk, A; Kozłowska, A; Olewińska, E; Machoń-Grecka, A; Kasperczyk, S

    2017-07-01

    There are many discrepancies among the results of studies on the genotoxicity of lead. The aim of the study was to explore lead-induced DNA damage, including oxidative damage, in relation to oxidative stress intensity parameters and the antioxidant defense system in human leukocytes. The study population consisted of 100 male workers exposed to lead. According to the blood lead (PbB) levels, they were divided into the following three subgroups: a group with PbB of 20-35 μg/dL (low exposure to lead (LE) group), a group with a PbB of 35-50 µg/dL (medium exposure to lead (ME) group), and a group with a PbB of >50 μg/dL (high exposure to lead (HE) group). The control group consisted of 42 healthy males environmentally exposed to lead (PbB lead exposure induces DNA damage, including oxidative damage, in human leukocytes. The increase in DNA damage was accompanied by an elevated intensity of oxidative stress.

  8. Oxidative stress-mediated antibacterial activity of graphene oxide and reduced graphene oxide in Pseudomonas aeruginosa

    OpenAIRE

    Gurunathan, Sangiliyandi; Han,Jae Woong; Abdal Daye,Ahmed; Eppakayala,Vasuki; Kim,Jin-Hoi

    2012-01-01

    Sangiliyandi Gurunathan, Jae Woong Han, Ahmed Abdal Dayem, Vasuki Eppakayala, Jin-Hoi KimDepartment of Animal Biotechnology, Konkuk University, Seoul, South KoreaBackground: Graphene holds great promise for potential use in next-generation electronic and photonic devices due to its unique high carrier mobility, good optical transparency, large surface area, and biocompatibility. The aim of this study was to investigate the antibacterial effects of graphene oxide (GO) and reduced graphene oxid...

  9. CATALYTIC OXIDATION OF ALCOHOLS AND EPOXIDATION OF OLEFINS WITH HYDROGEN PEROXIDE AS OXIDANT

    Science.gov (United States)

    Hydrogen peroxide (H2O2) is an ideal oxidant of choice for these oxidations due to economic and environmental reasons by giving water as a by-product. Two catalysts used are vanadium phosphorus oxide (VPO) and Fe3+/montmorillonite-K10 catalyst prepared by ion-exchange method at a...

  10. Nanoroses of nickel oxides: Synthesis, electron tomography study, and application in CO oxidation and energy storage

    KAUST Repository

    Fihri, Aziz; Sougrat, Rachid; Baby, Rakhi Raghavan; Rahal, Raed; Cha, Dong Kyu; Hedhili, Mohamed N.; Bouhrara, Mohamed; Alshareef, Husam N.; Polshettiwar, Vivek

    2012-01-01

    Nickel oxide and mixed-metal oxide structures were fabricated by using microwave irradiation in pure water. The nickel oxide self-assembled into unique rose-shaped nanostructures. These nickel oxide roses were studied by performing electron

  11. Carbon monoxide oxidation over three different states of copper: Development of a model metal oxide catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Jernigan, Glenn Geoffrey [California Univ., Berkeley, CA (United States). Dept. of Chemistry

    1994-10-01

    Carbon monoxide oxidation was performed over the three different oxidation states of copper -- metallic (Cu), copper (I) oxide (Cu2O), and copper (II) oxide (CuO) as a test case for developing a model metal oxide catalyst amenable to study by the methods of modern surface science and catalysis. Copper was deposited and oxidized on oxidized supports of aluminum, silicon, molybdenum, tantalum, stainless steel, and iron as well as on graphite. The catalytic activity was found to decrease with increasing oxidation state (Cu > Cu2O > CuO) and the activation energy increased with increasing oxidation state (Cu, 9 kcal/mol < Cu2O, 14 kcal/mol < CuO, 17 kcal/mol). Reaction mechanisms were determined for the different oxidation states. Lastly, NO reduction by CO was studied. A Cu and CuO catalyst were exposed to an equal mixture of CO and NO at 300--350 C to observe the production of N2 and CO2. At the end of each reaction, the catalyst was found to be Cu2O. There is a need to study the kinetics of this reaction over the different oxidation states of copper.

  12. Oxidative desulfurization of benzene fraction on transition metal oxides

    Science.gov (United States)

    Boikov, E. B.; Vishnetskaya, M. V.

    2013-02-01

    It is established that molecular oxygen is able to oxidize thiophene selectively in a mixture with benzene on V2O5 · MoO3. The introduction of thiophene inhibits the oxidation of benzene. It is shown that the conversion of thiophene during operation of the catalyst is reduced at first and then increases until it reaches its initial value.

  13. Nanoparticular metal oxide/anatase catalysts

    DEFF Research Database (Denmark)

    2010-01-01

    The present invention concerns a method of preparation of nanoparticular metal oxide catalysts having a narrow particle size distribution. In particular, the invention concerns preparation of nanoparticular metal oxide catalyst precursors comprising combustible crystallization seeds upon which...... the catalyst metai oxide is co-precipitated with the carrier metal oxide, which crystallization seeds are removed by combustion in a final calcining step. The present invention also concerns processes wherein the nanoparticular metal oxide catalysts of the invention are used, such as SCR (deNOx) reactions...

  14. The oxidative hypothesis of senescence

    Directory of Open Access Journals (Sweden)

    Gilca M

    2007-01-01

    Full Text Available The oxidative hypothesis of senescence, since its origin in 1956, has garnered significant evidence and growing support among scientists for the notion that free radicals play an important role in ageing, either as "damaging" molecules or as signaling molecules. Age-increasing oxidative injuries induced by free radicals, higher susceptibility to oxidative stress in short-lived organisms, genetic manipulations that alter both oxidative resistance and longevity and the anti-ageing effect of caloric restriction and intermittent fasting are a few examples of accepted scientific facts that support the oxidative theory of senescence. Though not completely understood due to the complex "network" of redox regulatory systems, the implication of oxidative stress in the ageing process is now well documented. Moreover, it is compatible with other current ageing theories (e.g., those implicating the mitochondrial damage/mitochondrial-lysosomal axis, stress-induced premature senescence, biological "garbage" accumulation, etc. This review is intended to summarize and critically discuss the redox mechanisms involved during the ageing process: sources of oxidant agents in ageing (mitochondrial -electron transport chain, nitric oxide synthase reaction- and non-mitochondrial- Fenton reaction, microsomal cytochrome P450 enzymes, peroxisomal β -oxidation and respiratory burst of phagocytic cells, antioxidant changes in ageing (enzymatic- superoxide dismutase, glutathione-reductase, glutathion peroxidase, catalase- and non-enzymatic glutathione, ascorbate, urate, bilirubine, melatonin, tocopherols, carotenoids, ubiquinol, alteration of oxidative damage repairing mechanisms and the role of free radicals as signaling molecules in ageing.

  15. The study of the oxidation of the natural flavonol fisetin confirmed quercetin oxidation mechanism

    International Nuclear Information System (INIS)

    Ramešová, Šárka; Sokolová, Romana; Degano, Ilaria

    2015-01-01

    Highlights: • The oxidation mechanisms of fisetin and quercetin were compared. • The oxidation product of fisetin was identified even if it was not stable. • A benzofuranon derivative is the common oxidation product of flavonols. • Fisetin decomposes in solution during minutes handled in the presence of air. - Abstract: Oxidation of the bioactive flavonoid fisetin was studied under inert atmosphere and under ambient conditions. The presence of fast subsequent chemical reactions following the electron transfer was supported by in situ spectroelectrochemistry and identification of products by HPLC-DAD and HPLC–ESI-MS/MS. In the absence of oxygen, 2,6-dihydroxy-2-(3′,4′-dihydroxybenzoyl)-benzofuran-3(2H)-one was identified as the only oxidation product of fisetin. This product was found also as the main oxidation product in the presence of oxygen. The oxidation pathway leading to formation of a benzofuranone derivative can be considered as common for flavonols containing C2-C3 double bond, C3-OH group and dihydroxy-substituted phenyl moiety in its structure. This product was not stable and decomposed further even in contact with oxygen coming from eluents during chromatography. Two oxidation pathways occur under ambient conditions. DFT calculations support the result.

  16. Ytterbia doped nickel–manganese mixed oxide catalysts for liquid phase oxidation of benzyl alcohol

    Directory of Open Access Journals (Sweden)

    S.S.P. Sultana

    2017-11-01

    Full Text Available Nickel–manganese mixed oxides doped with 1, 3, 5 mol% ytterbia have been prepared by co-precipitation method and used in the catalytic oxidation of benzyl alcohol. Catalytic activity of these oxides calcined at 400 °C and 500 °C was studied for selective oxidation of benzyl alcohol to the corresponding aldehyde using molecular oxygen as an oxidizing agent. The results showed that thermally stable 5 mol% ytterbia doped nickel–manganese oxide [Yb2O3-(5%-Ni6MnO8] exhibited highest catalytic performance when it was calcined at 400 °C. A 100% conversion of the benzyl alcohol was achieved with >99% selectivity to benzaldehyde within a reaction period of 5 h at 100 °C. The mixed oxide prepared has been characterized by scanning election microscopy (SEM and energy dispersive X-ray analysis (EDXA, X-ray diffraction (XRD, Fourier transform infrared spectroscopy (FT-IR, thermogravimetric analysis (TGA, Brunauer–Emmett–Teller (BET and temperature programed reduction (H2-TPR.

  17. High temperature oxidation resistant cermet compositions

    Science.gov (United States)

    Phillips, W. M. (Inventor)

    1976-01-01

    Cermet compositions are designed to provide high temperature resistant refractory coatings on stainless steel or molybdenum substrates. A ceramic mixture of chromium oxide and aluminum oxide form a coating of chromium oxide as an oxidation barrier around the metal particles, to provide oxidation resistance for the metal particles.

  18. Hydrogen oxidation in Azospirillum brasilense

    Energy Technology Data Exchange (ETDEWEB)

    Tibelius, K.

    1984-01-01

    Hydrogen oxidation by Azospirillum brasilense Sp7 was studied in N/sub 2/-fixing and NH/sub 4//sup +/-grown batch cultures. The K/sub m/ for H/sub 2/ of O/sub 2/-dependent H/sup 3/H oxidation in whole cells was 9 uM. The rates of H/sup 3/H and H/sub 2/ oxidation were very similar, indicating that the initial H/sub 2/ activation step in the overall H/sub 2/ oxidation reaction was not rate-limiting and that H/sup 3/H oxidation was a valid measure of H/sub 2/-oxidation activity. Hydrogen-oxidation activity was inhibited irreversibly by air. In N-free cultures the O/sub 2/ optima for O/sub 2/-dependent H/sub 2/ oxidation, ranging from 0.5-1.25% O/sub 2/ depending on the phase of growth, were significantly higher than those of C/sub 2/H/sub 2/ reduction, 0.15-0.35%, suggesting that the H/sub 2/-oxidation system may have a limited ability to aid in the protection of nitrogenase against inactivation by O/sub 2/. Oxygen-dependent H/sub 2/ oxidation was inhibited by NO/sub 2//sup +/, NO, CO, and C/sub 2/H/sub 2/ with apparent K/sub 1/ values of 20, 0.4, 28, and 88 uM, respectively. Hydrogen-oxidation activity was 50 to 100 times higher in denitrifying cultures when the terminal electron acceptor for growth was N/sub 2/O rather than NO/sub 3//sup -/, possibly due to the irreversible inhibition of hydrogenase by NO/sub 2//sup -/ and NO in NO/sub 3//sup -/-grown cultures.

  19. Contribution to characteristics of uranium oxides

    International Nuclear Information System (INIS)

    Fritsche, R.; Dahlkamp, F.J.

    2001-01-01

    Uranium oxides from pegmatitic, metamorphic and metasomatic uranium occurrences were investigated with the objective to check for differences in their physico-chemical properties and, whether such properties are sufficiently distinct to be applied as an exploration tool. Research methods included microscopy, electron microprobe and X-ray diffractometry amended by determinations of reflectance, Vickers hardness, unit-cell dimension and oxidation grade. Tentative research results are as follows: (a) U-oxides (uraninites) of pegmatites always contain significant amounts of Th (1,5-10 wt.% ThO2). (b) U-oxides from metasomatic environments have high, but variable contents of Fe, Ca, Ti, Si and Th (around 10 wt.%), Th being low. (c) U-oxides crystallised during metamorphism contain minor impurities of the above listed elements (total of oxides < 2 wt.%). (d) Redistributed U-oxides have elevated amounts of these elements. (e) Unit-cell dimensions of U-oxides tend to reflect a complex function of formation temperature, oxidation grade and the influence of incorporated elements caused by their radius and electro-negativity. (f) A global negative correlation of unit-cell dimension and oxidation grade of uranium oxides is indicated but based on widely varying ratios of the two parameters. (g) Colloform U-oxide (pitchblende) is characterised by elevated Ca-contents (1-5 wt.% CaO) and an almost complete lack of Th (< 1 wt.% ThO2). (h) Idiomorphic U-oxide (uraninite) is commonly low in Ca (< 1.5 wt.% CaO) but contains relatively high Th values. (i) The reflectance of U-oxides generally correlates positively with Vickers hardness and unit-cell dimension, but the incorporation of other elements in the lattice of U-oxides may cause strong interference. (author)

  20. Oxidation of propane with oxygen, nitrous oxide and oxygen/nitrous oxide mixture over Co- and Fe-zeolites

    Czech Academy of Sciences Publication Activity Database

    Novoveská, K.; Bulánek, R.; Wichterlová, Blanka

    2005-01-01

    Roč. 100, 3-4 (2005), s. 315-319 ISSN 0920-5861 R&D Projects: GA ČR(CZ) GA104/03/1120 Institutional research plan: CEZ:AV0Z40400503 Keywords : propene * propane oxidation * nitrous oxide * Fe-ZSM-5 Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.365, year: 2005

  1. N-Oxide-N-oxide interactions and Cl...Cl halogen bonds in pentachloropyridine N-oxide: the many-body approach to interactions in the crystal state.

    Science.gov (United States)

    Wzgarda-Raj, Kinga; Rybarczyk-Pirek, Agnieszka J; Wojtulewski, Sławomir; Palusiak, Marcin

    2018-02-01

    Pentachloropyridine N-oxide, C 5 Cl 5 NO, crystallizes in the monoclinic space group P2 1 /c. In the crystal structure, molecules are linked by C-Cl...Cl halogen bonds into infinite ribbons extending along the crystallographic [100] direction. These molecular aggregates are further stabilized by very short intermolecular N-oxide-N-oxide interactions into herringbone motifs. Computations based on quantum chemistry methods allowed for a more detailed description of the N-oxide-N-oxide interactions and Cl...Cl halogen bonds. For this purpose, Hirshfeld surface analysis and the many-body approach to interaction energy were applied.

  2. [Isolation and identification of Mn oxidizing bacterium Aminobacter sp. H1 and its oxidation mechanism].

    Science.gov (United States)

    Yan, Ping; Jiang, Li-Ying; Chen, Jian-Meng; He, Zhi-Min; Xiao, Shao-Dan; Jiang, Yi-Feng

    2014-04-01

    A bacterium with high manganese oxidizing activity was isolated from a biological manganese removal filter and named as H1. Based on its characteristics and the analysis of 16S rDNA sequence, the strain H1 belonged to the genus Aminobacter sp. and its manganese oxidizing ability had never been reported. In this paper, the microbiologic properties of the strain H1, the manganese oxidation mechanisms and characteristics of biogenic manganese oxides were investigated. The results showed that the maximal tolerant Mn concentration of strain H1 was 50 mmol x L(-1), and Mn(II) could be completely removed by strain H1 when the concentration was lower than 10 mmol x L(-1). Strain H1 could oxidize Mn2+ by both the production of manganese oxidizing activity factor and alkaline metabolites during growth, which were synthesized in the cell and then secreted into extracellular culture medium. During the oxidation process, the intermediate of soluble Mn(III) was detected. SEM showed that the biogenic manganese oxides were amorphous and poorly-crystalline, and it closely combined with bacteria. The components of the biogenic manganese oxides produced by strain H1 were identified as MnCO3, MnOOH, Mn3O4 and MnO2 by XRD, XPS and SEM-EDX.

  3. Metal oxide nanorod arrays on monolithic substrates

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Pu-Xian; Guo, Yanbing; Ren, Zheng

    2018-01-02

    A metal oxide nanorod array structure according to embodiments disclosed herein includes a monolithic substrate having a surface and multiple channels, an interface layer bonded to the surface of the substrate, and a metal oxide nanorod array coupled to the substrate surface via the interface layer. The metal oxide can include ceria, zinc oxide, tin oxide, alumina, zirconia, cobalt oxide, and gallium oxide. The substrate can include a glass substrate, a plastic substrate, a silicon substrate, a ceramic monolith, and a stainless steel monolith. The ceramic can include cordierite, alumina, tin oxide, and titania. The nanorod array structure can include a perovskite shell, such as a lanthanum-based transition metal oxide, or a metal oxide shell, such as ceria, zinc oxide, tin oxide, alumina, zirconia, cobalt oxide, and gallium oxide, or a coating of metal particles, such as platinum, gold, palladium, rhodium, and ruthenium, over each metal oxide nanorod. Structures can be bonded to the surface of a substrate and resist erosion if exposed to high velocity flow rates.

  4. Pyrite oxidation in unsaturated aquifer sediments. Reaction stoichiometry and rate of oxidation

    DEFF Research Database (Denmark)

    Andersen, Martin Søgaard; Larsen, Flemming; Postma, Diederik Jan

    2001-01-01

    The oxidation of pyrite (FeS2) contained in unsaturated aquifer sediment was studied by sediment incubation in gas impermeable polymer laminate bags. Reaction progress was followed over a period of nearly 2 months by monitoring the gas composition within the laminate bag. The gas phase in the inc......The oxidation of pyrite (FeS2) contained in unsaturated aquifer sediment was studied by sediment incubation in gas impermeable polymer laminate bags. Reaction progress was followed over a period of nearly 2 months by monitoring the gas composition within the laminate bag. The gas phase...... in the incubation bags became depleted in O2 and enriched in CO2 and N2 and was interpreted as due to pyrite oxidation in combination with calcite dissolution. Sediment incubation provides a new method to estimate low rates of pyrite oxidation in unsaturated zone aquifer sediments. Oxidation rates of up to 9.4â10......-10 mol FeS2/gâs are measured, and the rates are only weakly correlated with the sediment pyrite content. The reactivity of pyrite, including the inhibition by FeOOH layers formed on its surface, apparently has a major effect on the rate of oxidation. The code PHREEQC 2.0 was used to calculate...

  5. A set-valued approach to FDI an FTC of wind turbines

    DEFF Research Database (Denmark)

    Casau, Pedro; Rosa, Paulo; Tabatabaeipour, Mojtaba

    2015-01-01

    A complete methodology to design robust Fault Detection and Isolation (FDI) filters and Fault Tolerant Control (FTC) schemes for Linear Parameter Varying (LPV) systems is proposed, with particular focus on its applicability to wind turbines. The paper takes advantage of the recent advances in model...... falsification using Set-Valued Observers (SVOs) that led to the development of FDI methods for uncertain linear time-varying systems, with promising results in terms of the time required to diagnose faults. An integration of such SVO-based FDI methods with robust control synthesis is described, in order...

  6. Oxidation kinetics and auger microprobe analysis of some oxidized zirconium alloys

    International Nuclear Information System (INIS)

    Ploc, R.A.

    1989-01-01

    Oxidation kinetics at 300 o C in dry oxygen of 0.5 wt% binary alloys of iron, nickel, and chromium in zirconium were determined for several surface preparations. Further, chemical profiles of the oxides as they existed on the matrix and on the precipitates were obtained by sputtering and Auger electron analysis. The appearance of 'breakaway' oxidation was controlled by the surface finish of the alloy, a variable that could be used to eliminate the phenomenon for all alloys except the Zr/Ni binary, which required β-quenching to accomplish the same purpose. (author)

  7. Reduction of graphene oxide by aniline with its concomitant oxidative polymerization.

    Science.gov (United States)

    Xu, Li Qun; Liu, Yi Liang; Neoh, Koon-Gee; Kang, En-Tang; Fu, Guo Dong

    2011-04-19

    Graphene oxide (GO) nanosheets are readily reduced by aniline above room temperature in an aqueous acid medium, with the aniline simultaneously undergoing oxidative polymerization to produce the reduced graphene oxide-polyaniline nanofiber (RGO-PANi) composites. The resulting RGO-PANi composites and RGO (after dissolution of PANi) were characterized by XPS, XRD analysis, TGA, UV-visible absorption spectroscopy, and TEM. It was also found that the RGO-PANi composites exhibit good specific capacitance during galvanostatic charging-discharging when used as capacitor electrodes. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Lipid oxidation. Part 2. Oxidation products of olive oil methyl esters.

    Science.gov (United States)

    Pokorný, J; Tài, P; Parízková, H; Smidrkalová, E; El-Tarras, M F; Janícek, G

    1976-01-01

    Olive oil was converted into methyl esters which were autoxidized at 60 degrees C. The composition of oxidized products was determined by the comparison of infrared spectra and NMR spectra of the original and acetylated samples, the sample reduced with potassium iodide and the acetylated reduced sample. Oxidized products were separated by preparative thin layer chromatography on silica gel and characterized by selective detection and by infrared spectrometry of the fractions. The oxidation products consisted of hydroperoxido butyl oleate, substituted hydroperoxides, mono- and disubstituted monomeric derivatives and a small amount of oligomers.

  9. The distinguishing characteristics of interlayer oxidation zone and burial ancient ground oxidation zone

    International Nuclear Information System (INIS)

    Zhang Zhanshi; Zhou Wenbin

    1998-01-01

    The author discusses the main characteristics of interlayer oxidation zones and the burial ancient ground oxidation zones of Uranium deposit No. 512 in Xinjiang Uigur municipality. The epigenetic genesis, depending on some aquifer, the tongue-like in section, having the zonation along dip direction and having certain mineral assemblage are the typical features for interlayer oxidation zones

  10. Review of zircaloy oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Iglesias, F.C. [Royal Military College of Canada, Kingston, Ontario (Canada); Lewis, B.J. [Univ. of Ontario Inst. of Technology, Faculty of Energy Systems and Nuclear Science, Oshawa, Ontario (Canada)

    2013-07-01

    This paper provides an overview of the kinetics for Zircaloy clad oxidation behaviour in steam and air during reactor accident conditions. The generation of chemical heat from metal/water reaction is considered. The effect of internal clad oxidation due to Zircaloy/UO{sub 2} interaction is also discussed. Low-temperature oxidation of Zircaloy due to water-side corrosion is further described. (author)

  11. Mesoporous Transition Metal Oxides for Supercapacitors

    OpenAIRE

    Wang, Yan; Guo, Jin; Wang, Tingfeng; Shao, Junfeng; Wang, Dong; Yang, Ying-Wei

    2015-01-01

    Recently, transition metal oxides, such as ruthenium oxide (RuO2), manganese dioxide (MnO2), nickel oxides (NiO) and cobalt oxide (Co3O4), have been widely investigated as electrode materials for pseudo-capacitors. In particular, these metal oxides with mesoporous structures have become very hot nanomaterials in the field of supercapacitors owing to their large specific surface areas and suitable pore size distributions. The high specific capacities of these mesoporous metal oxides are result...

  12. Elaboration and characterisation of yttrium oxide and hafnium oxide powders by the sol-gel process

    International Nuclear Information System (INIS)

    Hours, T.

    1988-01-01

    The two classical sol-gel processes, colloidal and polymeric are studied for the preparation of yttrium oxide and hafnium oxide high performance powders. In the colloidal process, controlled and reproducible conditions for the preparation of yttrium oxide and hafnium oxide sols from salts or alkoxides are developed and the hydrothermal synthesis monodisperse hafnium oxide colloids is studied. The polymeric process is studied with hafnium ethyl-hexylate, hydrolysis kinetics for controlled preparation of sols and gels is investigated. Each step of preparation is detailed and powders obtained are characterized [fr

  13. Modes of oxidation in SiC-reinforced mullite/ZrO2 composites: Oxidation vs depth behavior

    International Nuclear Information System (INIS)

    Lin, C.C.; Ruh, R.

    1999-01-01

    Two basic oxidation modes of composites with oxidizing particles in a non-oxidizing matrix have been observed. Mode I is defined as the complete oxidation of all the particles within an outer layer of the composite, while mode II exhibits partial oxidation of the particles, deep into the composite. Using microscopic observations to plot the silica layer thickness on particles (whiskers) vs the depth of the particles (whiskers) below the composite surface is proposed as a powerful means of categorizing and quantifying actual oxidation modes. Thus, mullite/SiC-whisker composites were found to have mode I oxidation behavior, while certain (mullite + ZrO 2 )/SiC-whisker composites were found to exhibit mode II behavior, followed by a mixed mode after severe exposures. It is proposed that mode II behavior appears when oxygen diffusivity in the matrix is much higher than that in the product oxide layer

  14. Evolution of Near-Surface Internal and External Oxide Morphology During High-Temperature Selective Oxidation of Steels

    Science.gov (United States)

    Story, Mary E.; Webler, Bryan A.

    2018-05-01

    In this work we examine some observations made using high-temperature confocal scanning laser microscopy (HT-CSLM) during selective oxidation experiments. A plain carbon steel and advanced high-strength steel (AHSS) were selectively oxidized at high temperature (850-900°C) in either low oxygen or water vapor atmospheres. Surface evolution, including thermal grooving along grain boundaries and oxide growth, was viewed in situ during heating. Experiments investigated the influence of the microstructure and oxidizing atmosphere on selective oxidation behavior. Sequences of CSLM still frames collected during the experiment were processed with ImageJ to obtain histograms that showed a general darkening trend indicative of oxidation over time with all samples. Additional ex situ scanning electron microscopy and energy dispersive spectroscopy analysis supported in situ observations. Distinct oxidation behavior was observed for each case. Segregation, grain orientation, and extent of internal oxidation were all found to strongly influence surface evolution.

  15. Charge transfer in rectifying oxide heterostructures and oxide access elements in ReRAM

    Energy Technology Data Exchange (ETDEWEB)

    Stefanovich, G. B.; Pergament, A. L.; Boriskov, P. P.; Kuroptev, V. A., E-mail: v.a.kuroptev@gmail.com; Stefanovich, T. G. [Petrozavodsk State University (Russian Federation)

    2016-05-15

    The main aspects of the synthesis and experimental research of oxide diode heterostructures are discussed with respect to their use as selector diodes, i.e., access elements in oxide resistive memory. It is shown that charge transfer in these materials differs significantly from the conduction mechanism in p–n junctions based on conventional semiconductors (Si, Ge, A{sup III}–B{sup V}), and the model should take into account the electronic properties of oxides, primarily the low carrier drift mobility. It is found that an increase in the forward current requires an oxide with a small band gap (<1.3 eV) in the heterostructure composition. Heterostructures with Zn, In–Zn (IZO), Ti, Ni, and Cu oxides are studied; it is found that the CuO–IZO heterojunction has the highest forward current density (10{sup 4} A/cm{sup 2}).

  16. Cordierite-supported metal oxide for non-methane hydrocarbon oxidation in cooking oil fumes.

    Science.gov (United States)

    Huang, Yonghai; Yi, Honghong; Tang, Xiaolong; Zhao, Shunzheng; Gao, Fengyu; Wang, Jiangen; Yang, Zhongyu

    2018-05-21

    Cooking emission is an important reason for the air quality deterioration in the metropolitan area in China. Transition metal oxide and different loading of manganese oxide supported on cordierite were prepared by incipient wetness impregnation method and were used for non-methane hydrocarbon (NMHC) oxidation in cooking oil fumes (COFs). The effects of different calcination temperature and different Mn content were also studied. The SEM photographs and CO 2 temperature-programmed desorption revealed 5 wt% Mn/cordierite had the best pore structure and the largest number of the weak and moderate basic sites so it showed the best performance for NMHC oxidation. XRD analysis exhibited 5 wt% Mn/cordierite had the best dispersion of active phase and the active phase was MnO 2 when the calcination temperature was 400℃ which were good for the catalytic oxidation of NMHC.

  17. Effect of oxygen on decomposition of nitrous oxide over various metal oxide catalysts

    International Nuclear Information System (INIS)

    Satsuma, Atsushi; Maeshima, Hajime; Watanabe, Kiyoshi; Hattori, Tadashi

    2001-01-01

    The inhibitory effect of oxygen on decomposition of nitrous oxide over various metal oxide catalysts was investigated. The activity of nitrous oxide decomposition significantly decreased over CuO, Co 3 O 4 , NiO, Fe 2 O 3 , SnO 2 , In 2 O 3 and Cr 2 O 3 by reversible adsorption of oxygen onto the active sites. On the contrary to this, there was no or small change in the activity of TiO 2 , Al 2 O 3 , MgO, La 2 O 3 and CaO. A good correlation was observed between the degree of inhibition and the heat of formation of metal oxides. On the basis of kinetic model, the reduction of catalytic activity in the presence of oxygen was rationalized with the strength of oxygen adsorption on the metal oxide surface. (author)

  18. 21 CFR 184.1545 - Nitrous oxide.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Nitrous oxide. 184.1545 Section 184.1545 Food and... Substances Affirmed as GRAS § 184.1545 Nitrous oxide. (a) Nitrous oxide (empirical formula N2O, CAS Reg. No.... Nitrous oxide is manufactured by the thermal decomposition of ammonium nitrate. Higher oxides of nitrogen...

  19. Oxidative stress

    Directory of Open Access Journals (Sweden)

    Stevanović Jelka

    2012-01-01

    Full Text Available The unceasing need for oxygen is in contradiction to the fact that it is in fact toxic to mammals. Namely, its monovalent reduction can have as a consequence the production of short-living, chemically very active free radicals and certain non-radical agents (nitrogen-oxide, superoxide-anion-radicals, hydroxyl radicals, peroxyl radicals, singlet oxygen, peroxynitrite, hydrogen peroxide, hypochlorous acid, and others. There is no doubt that they have numerous positive roles, but when their production is stepped up to such an extent that the organism cannot eliminate them with its antioxidants (superoxide-dismutase, glutathione-peroxidase, catalase, transferrin, ceruloplasmin, reduced glutathion, and others, a series of disorders is developed that are jointly called „oxidative stress.“ The reactive oxygen species which characterize oxidative stress are capable of attacking all main classes of biological macromolecules, actually proteins, DNA and RNA molecules, and in particular lipids. The free radicals influence lipid peroxidation in cellular membranes, oxidative damage to DNA and RNA molecules, the development of genetic mutations, fragmentation, and the altered function of various protein molecules. All of this results in the following consequences: disrupted permeability of cellular membranes, disrupted cellular signalization and ion homeostasis, reduced or loss of function of damaged proteins, and similar. That is why the free radicals that are released during oxidative stress are considered pathogenic agents of numerous diseases and ageing. The type of damage that will occur, and when it will take place, depends on the nature of the free radicals, their site of action and their source. [Projekat Ministarstva nauke Republike Srbije, br. 173034, br. 175061 i br. 31085

  20. Comparison of direct and indirect plasma oxidation of NO combined with oxidation by catalyst

    DEFF Research Database (Denmark)

    Jogi, Indrek; Stamate, Eugen; Irimiea, Cornelia

    2015-01-01

    of the DBD reactor decreased the long-term efficiency of direct plasma oxidation. At the same time, the efficiency of indirect oxidation increased at elevated reactor temperatures. Additional experiments were carried out to investigate the improvement of indirect oxidation by the introduction of catalyst...

  1. Electrochemical Oxidation by Square-Wave Potential Pulses in the Imitation of Oxidative Drug Metabolism

    NARCIS (Netherlands)

    Nouri-Nigjeh, Eslam; Permentier, Hjalmar P.; Bischoff, Rainer; Bruins, Andries P.

    2011-01-01

    Electrochemistry combined with mass spectrometry (EC-MS) is an emerging analytical technique in the imitation of oxidative drug metabolism at the early stages of new drug development. Here, we present the benefits of electrochemical oxidation by square-wave potential pulses for the oxidation of

  2. Oxidative Metabolism Genes Are Not Responsive to Oxidative Stress in Rodent Beta Cell Lines

    Directory of Open Access Journals (Sweden)

    Faer Morrison

    2012-01-01

    Full Text Available Altered expression of oxidative metabolism genes has been described in the skeletal muscle of individuals with type 2 diabetes. Pancreatic beta cells contain low levels of antioxidant enzymes and are particularly susceptible to oxidative stress. In this study, we explored the effect of hyperglycemia-induced oxidative stress on a panel of oxidative metabolism genes in a rodent beta cell line. We exposed INS-1 rodent beta cells to low (5.6 mmol/L, ambient (11 mmol/L, and high (28 mmol/L glucose conditions for 48 hours. Increases in oxidative stress were measured using the fluorescent probe dihydrorhodamine 123. We then measured the expression levels of a panel of 90 oxidative metabolism genes by real-time PCR. Elevated reactive oxygen species (ROS production was evident in INS-1 cells after 48 hours (P<0.05. TLDA analysis revealed a significant (P<0.05 upregulation of 16 of the 90 genes under hyperglycemic conditions, although these expression differences did not reflect differences in ROS. We conclude that although altered glycemia may influence the expression of some oxidative metabolism genes, this effect is probably not mediated by increased ROS production. The alterations to the expression of oxidative metabolism genes previously observed in human diabetic skeletal muscle do not appear to be mirrored in rodent pancreatic beta cells.

  3. RNA modifications by oxidation

    DEFF Research Database (Denmark)

    Poulsen, Henrik E; Specht, Elisabeth; Broedbaek, Kasper

    2012-01-01

    to encompass various classes of novel regulatory RNAs, including, e.g., microRNAs. It is well known that DNA is constantly oxidized and repaired by complex genome maintenance mechanisms. Analogously, RNA also undergoes significant oxidation, and there are now convincing data suggesting that oxidation......The past decade has provided exciting insights into a novel class of central (small) RNA molecules intimately involved in gene regulation. Only a small percentage of our DNA is translated into proteins by mRNA, yet 80% or more of the DNA is transcribed into RNA, and this RNA has been found......, and the consequent loss of integrity of RNA, is a mechanism for disease development. Oxidized RNA is found in a large variety of diseases, and interest has been especially devoted to degenerative brain diseases such as Alzheimer disease, in which up to 50-70% of specific mRNA molecules are reported oxidized, whereas...

  4. Isotopes in oxidation reactions

    International Nuclear Information System (INIS)

    Stewart, R.

    1976-01-01

    The use of isotopes in the study of organic oxidation mechanisms is discussed. The help provided by tracer studies to demonstrate the two-equivalent path - hydride transfer, is illustrated by the examples of carbonium oxidants and the Wacker reaction. The role of kinetic isotope effects in the study of the scission of carbon-hydrogen bonds is illustrated by hydride abstraction, hydrogen atom abstraction, proton abstraction and quantum mechanical tunnelling. Isotopic studies on the oxidation of alcohols, carbonyl compounds, amines and hydrocarbons are discussed. The role of isotopes in the study of biochemical oxidation is illustrated with a discussion on nicotinamide and flavin coenzymes. (B.R.H.)

  5. Aspirin increases mitochondrial fatty acid oxidation

    International Nuclear Information System (INIS)

    Uppala, Radha; Dudiak, Brianne; Beck, Megan E.; Bharathi, Sivakama S.; Zhang, Yuxun; Stolz, Donna B.; Goetzman, Eric S.

    2017-01-01

    The metabolic effects of salicylates are poorly understood. This study investigated the effects of aspirin on fatty acid oxidation. Aspirin increased mitochondrial long-chain fatty acid oxidation, but inhibited peroxisomal fatty acid oxidation, in two different cell lines. Aspirin increased mitochondrial protein acetylation and was found to be a stronger acetylating agent in vitro than acetyl-CoA. However, aspirin-induced acetylation did not alter the activity of fatty acid oxidation proteins, and knocking out the mitochondrial deacetylase SIRT3 did not affect the induction of long-chain fatty acid oxidation by aspirin. Aspirin did not change oxidation of medium-chain fatty acids, which can freely traverse the mitochondrial membrane. Together, these data indicate that aspirin does not directly alter mitochondrial matrix fatty acid oxidation enzymes, but most likely exerts its effects at the level of long-chain fatty acid transport into mitochondria. The drive on mitochondrial fatty acid oxidation may be a compensatory response to altered mitochondrial morphology and inhibited electron transport chain function, both of which were observed after 24 h incubation of cells with aspirin. These studies provide insight into the pathophysiology of Reye Syndrome, which is known to be triggered by aspirin ingestion in patients with fatty acid oxidation disorders. - Highlights: • Aspirin increases mitochondrial—but inhibits peroxisomal—fatty acid oxidation. • Aspirin acetylates mitochondrial proteins including fatty acid oxidation enzymes. • SIRT3 does not influence the effect of aspirin on fatty acid oxidation. • Increased fatty acid oxidation is likely due to altered mitochondrial morphology and respiration.

  6. OXIDATION OF TRANSURANIC ELEMENTS

    Science.gov (United States)

    Moore, R.L.

    1959-02-17

    A method is reported for oxidizing neptunium or plutonium in the presence of cerous values without also oxidizing the cerous values. The method consists in treating an aqueous 1N nitric acid solution, containing such cerous values together with the trivalent transuranic elements, with a quantity of hydrogen peroxide stoichiometrically sufficient to oxidize the transuranic values to the hexavalent state, and digesting the solution at room temperature.

  7. Volcano Relations for Oxidation of Hydrogen Halides over Rutile Oxide Surfaces

    DEFF Research Database (Denmark)

    Toftelund, Anja; Man, Isabela C.; Hansen, Heine A.

    2012-01-01

    over a range of different rutile oxide surfaces. Based on the scaling relations, two descriptors are identified that describe the reactions uniquely. By combining scaling with the micro-kinetic model, activity volcanoes for the three different oxidation reactions are derived. It is found...

  8. Oxidative dehydrogenation of ethane on rare-earth oxide-based catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Buyevskaya, O.; Baerns, M. [Institut fuer Angewandte Chemie Berlin-Adlershof e.V., Berlin (Germany)

    1998-12-31

    Results on the oxidative dehydrogenation of ethane on rare-earth oxide (REO) based catalysts (Na-P-Sm-O, Sm-Sr(Ca)-O, La-Sr-O and Nd-Sr-O) are described. Oxygen adsorption was found to be a key factor which determines the activity of this type of catalysts. Continuous flow experiments in the presence of catalysts which reveal strong oxygen adsorption showed that the reaction mixture is ignited resulting in an enhanced heat generation at the reactor inlet. The heat produced by the oxidative reactions was sufficient under the conditions chosen for the endothermic thermal pyrolysis which takes place preferentially in the gas phase. Ignition of the reaction mixture is an important catalyst function. Contrary to non-catalytic oxidative dehydrogenation, reaction temperatures above 700 C could be achieved without significant external heat input. Ethylene yields of up to 34-45% (S=66-73%) were obtained on REO-based catalysts under non-isothermal conditions (T{sub max}=810-865 C) at contact times in the order of 30 to 40 ms. (orig.)

  9. 21 CFR 186.1374 - Iron oxides.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Iron oxides. 186.1374 Section 186.1374 Food and... Substances Affirmed as GRAS § 186.1374 Iron oxides. (a) Iron oxides (oxides of iron, CAS Reg. No. 1332-37-2) are undefined mixtures of iron (II) oxide (CAS Reg. No. 1345-25-1, black cubic crystals) and iron (III...

  10. Oxidation under electron bombardment. A tool for studying the initial states of silicon oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Carriere, B.; Deville, J.P.; El Maachi, A.

    1987-06-01

    The exciting beam of an Auger electron spectrometer has been used to monitor the oxidation of silicon single crystals at room temperature and very low pressures of oxygen (approx. 10/sup -7/ Torr). This process allows us to build ultra-thin layers of silica on silicon (down to 30 A) but it is mostly used to investigate the mechanisms of the initial stages of oxidation. Auger spectra recorded continuously during the oxidation process provide information on (1) the nature of the silicon-oxygen chemical bonds which are interpreted through fine structure in the Auger peak, and (2) the kinetics of oxide formation which are deduced from curves of Auger signal versus time. An account is given of the contribution of these Auger studies to the description of the intermediate oxide layer during the reaction between silicon and oxygen and the influence of surface structural disorder, induced mainly by argon-ion bombardment, is discussed in terms of reactivity and oxide coverage.

  11. Oxidative desulphurization study of gasoline and kerosene. Role of some organic and inorganic oxidants

    Energy Technology Data Exchange (ETDEWEB)

    Shakirullah, M.; Ahmad, Waqas; Ahmad, Imtiaz; Ishaq, M.

    2010-11-15

    Desulphurization of gasoline and kerosene was carried out using organic and inorganic oxidants. Among the organic oxidants used were hydrogen peroxide in combination with acetic acid, formic acid, benzoic acid and butyric acid, while inorganic oxidants used included potassium permanganate and sodium perchlorate. The oxidation of each petroleum oil was carried out in two steps; the first step consisted of oxidation of the feed at moderate temperature and atmospheric pressure while in the second step, the oxidized mixture was extracted with azeotropic mixture of acetonitrile-water. A maximum desulphurization has occurred with NaClO{sub 4} and hydrogen peroxide and acetic acid, which are 68% and 61%, respectively in case of gasoline and 66% and 63%, respectively in case of kerosene oil. The FTIR study of the whole and variously desulphurized gasoline and kerosene was also carried out. The results indicate considerable desulphurization by absence of bands that corresponds to sulphur moieties in NaClO{sub 4} and hydrogen peroxide treated samples. (author)

  12. The development of latent fingerprints by zinc oxide and tin oxide nanoparticles prepared by precipitation technique

    Science.gov (United States)

    Luthra, Deepali; Kumar, Sacheen

    2018-05-01

    Fingerprints are the very important evidence at the crime scene which must be developed clearly with shortest duration of time to solve the case. Metal oxide nanoparticles could be the mean to develop the latent fingerprints. Zinc oxide and Tin Oxide Nanoparticles were prepared by using chemical precipitation technique which were dried and characterized by X-ray diffraction, UV-Visible spectroscopy and FTIR. The size of zinc oxide crystallite was found to be 14.75 nm with minimum reflectance at 360 nm whereas tin oxide have the size of 90 nm and reflectance at minimum level 321 nm. By using these powdered samples on glass, plastic and glossy cardboard, latent fingerprints were developed. Zinc oxide was found to be better candidate than tin oxide for the fingerprint development on all the three types of substrates.

  13. Plutonium oxide dissolution

    International Nuclear Information System (INIS)

    Gray, J.H.

    1992-01-01

    Several processing options for dissolving plutonium oxide (PuO 2 ) from high-fired materials have been studied. The scoping studies performed on these options were focused on PuO 2 typically generated by burning plutonium metal and PuO 2 produced during incineration of alpha contaminated waste. At least two processing options remain applicable for dissolving high-fired PuO 2 in canyon dissolvers. The options involve solid solution formation of PuO 2 With uranium oxide (UO 2 ) and alloying incinerator ash with aluminum. An oxidative dissolution process involving nitric acid solutions containing a strong oxidizing agent, such as cerium (IV), was neither proven nor rejected. This uncertainty was due to difficulty in regenerating cerium (IV) ions during dissolution. However, recent work on silver-catalyzed dissolution of PuO 2 with persulfate has demonstrated that persulfate ions regenerate silver (II). Use of persulfate to regenerate cerium (IV) or bismuth (V) ions during dissolution of PuO 2 materials may warrant further study

  14. Oxidation of nano-sized aluminum powders

    International Nuclear Information System (INIS)

    Vorozhtsov, A.B.; Lerner, M.; Rodkevich, N.; Nie, H.; Abraham, A.; Schoenitz, M.; Dreizin, E.L.

    2016-01-01

    Highlights: • Weight gain measured in TG oxidation experiments was split between particles of different sizes. • Reaction kinetics obtained by isoconversion explicitly accounting for the effect of size distribution. • Activation energy is obtained as a function of oxide thickness for growth of amorphous alumina. • Oxidation mechanism for nanopowders remains the same as for coarser aluminum powders. - Abstract: Oxidation of aluminum nanopowders obtained by electro-exploded wires is studied. Particle size distributions are obtained from transmission electron microscopy (TEM) images. Thermo-gravimetric (TG) experiments are complemented by TEM and XRD studies of partially oxidized particles. Qualitatively, oxidation follows the mechanism developed for coarser aluminum powder and resulting in formation of hollow oxide shells. Sintering of particles is also observed. The TG results are processed to account explicitly for the particle size distribution and spherical shapes, so that oxidation of particles of different sizes is characterized. The apparent activation energy is obtained as a function of the reaction progress using model-free isoconversion processing of experimental data. A complete phenomenological oxidation model is then proposed assuming a spherically symmetric geometry. The oxidation kinetics of aluminum powder is shown to be unaffected by particle sizes reduced down to tens of nm. The apparent activation energy describing growth of amorphous alumina is increasing at the very early stages of oxidation. The higher activation energy is likely associated with an increasing homogeneity in the growing amorphous oxide layer, initially containing multiple defects and imperfections. The trends describing changes in both activation energy and pre-exponent of the growing amorphous oxide are useful for predicting ignition delays of aluminum particles. The kinetic trends describing activation energies and pre-exponents in a broader range of the oxide

  15. Operation of staged membrane oxidation reactor systems

    Science.gov (United States)

    Repasky, John Michael

    2012-10-16

    A method of operating a multi-stage ion transport membrane oxidation system. The method comprises providing a multi-stage ion transport membrane oxidation system with at least a first membrane oxidation stage and a second membrane oxidation stage, operating the ion transport membrane oxidation system at operating conditions including a characteristic temperature of the first membrane oxidation stage and a characteristic temperature of the second membrane oxidation stage; and controlling the production capacity and/or the product quality by changing the characteristic temperature of the first membrane oxidation stage and/or changing the characteristic temperature of the second membrane oxidation stage.

  16. Nitrous oxide and perioperative outcomes.

    Science.gov (United States)

    Ko, Hanjo; Kaye, Alan David; Urman, Richard D

    2014-06-01

    There is emerging evidence related to the effects of nitrous oxide on important perioperative patient outcomes. Proposed mechanisms include metabolic effects linked to elevated homocysteine levels and endothelial dysfunction, inhibition of deoxyribonucleic acid and protein formation, and depression of chemotactic migration by monocytes. Newer large studies point to possible risks associated with the use of nitrous oxide, although data are often equivocal and inconclusive. Cardiovascular outcomes such as stroke or myocardial infarction were shown to be unchanged in previous studies, but the more recent Evaluation of Nitrous Oxide in the Gas Mixture for Anesthesia I trial shows possible associations between nitrous oxide and increased cardiovascular and pulmonary complications. There are also possible effects on postoperative wound infections and neuropsychological function, although the multifactorial nature of these complications should be considered. Teratogenicity linked to nitrous oxide use has not been firmly established. The use of nitrous oxide for routine anesthetic care may be associated with significant costs if complications such as nausea, vomiting, and wound infections are taken into consideration. Overall, definitive data regarding the effect of nitrous oxide on major perioperative outcomes are lacking. There are ongoing prospective studies that may further elucidate its role. The use of nitrous oxide in daily practice should be individualized to each patient's medical conditions and risk factors.

  17. Development of the inner oxide zone upon steam oxidation of an austenitic stainless steel

    DEFF Research Database (Denmark)

    Hansson, Anette N.; Montgomery, Melanie; Somers, Marcel A. J.

    2009-01-01

    The oxidation behaviour of TP 347H FG in mixtures of water, oxygen, and hydrogen was investigated in the temperature range 500 – 700C for a fixed oxidation time of 336 h. The samples were characterised using reflective light and electron microscopy methods. Thin discontinuous double-layered oxide...

  18. Oxidation kinetics of corium pool

    International Nuclear Information System (INIS)

    Sulatsky, A.A.; Smirnov, S.A.; Granovsky, V.S.; Khabensky, V.B.; Krushinov, E.V.; Vitol, S.A.; Kotova, S.Yu.; Fischer, M.; Hellmann, S.; Tromm, W.; Miassoedov, A.; Bottomley, D.; Piluso, P.; Barrachin, M.

    2013-01-01

    Highlights: • The analysis of experimental data on molten corium oxidation was been carried out. • The analysis has revealed the main factors influencing the oxidation kinetics. • The analysis was used for developing a qualitative analytical model. • The numerical modeling has confirmed the results of experimental data analysis. -- Abstract: Experimental, theoretical and numerical studies of oxidation kinetics of an open surface corium pool have been reported. The experiments have been carried out within OECD MASCA program and ISTC METCOR, METCOR-P and EVAN projects. It has been shown that the melt oxidation is controlled by an oxidant supply to the melt free surface from the atmosphere, not by the reducer supply from the melt. The project experiments have not detected any input of the zirconium oxidation kinetics into the process chemistry. The completed analysis puts forward a simple analytical model, which gives an explanation of the main features of melt oxidation process. The numerical modeling results are in good agreement with experimental data and theoretical considerations

  19. Oxidation kinetics of corium pool

    Energy Technology Data Exchange (ETDEWEB)

    Sulatsky, A.A., E-mail: andrei314@mail.ru [Alexandrov Research Institute of Technologies (NITI), Sosnovy Bor (Russian Federation); Smirnov, S.A. [D.V. Efremov Scientific Research Institute of Electrophysical Apparatus (NIIEFA), St. Petersburg (Russian Federation); Granovsky, V.S.; Khabensky, V.B.; Krushinov, E.V.; Vitol, S.A.; Kotova, S.Yu. [Alexandrov Research Institute of Technologies (NITI), Sosnovy Bor (Russian Federation); Fischer, M.; Hellmann, S. [AREVA NP GmbH, Erlangen (Germany); Tromm, W.; Miassoedov, A. [Forschungzentrum Karlsruhe (FZK), Karlsruhe (Germany); Bottomley, D. [EUROPÄISCHE KOMMISSION, Joint Research Centre Institut für Transurane (ITU), Karlsruhe (Germany); Piluso, P. [CEA Cadarache-DEN/DTN/STRI, St.Paul-lez-Durance (France); Barrachin, M. [Institut de Radioprotection et Sûreté Nucléaire, St.Paul-lez-Durance (France)

    2013-09-15

    Highlights: • The analysis of experimental data on molten corium oxidation was been carried out. • The analysis has revealed the main factors influencing the oxidation kinetics. • The analysis was used for developing a qualitative analytical model. • The numerical modeling has confirmed the results of experimental data analysis. -- Abstract: Experimental, theoretical and numerical studies of oxidation kinetics of an open surface corium pool have been reported. The experiments have been carried out within OECD MASCA program and ISTC METCOR, METCOR-P and EVAN projects. It has been shown that the melt oxidation is controlled by an oxidant supply to the melt free surface from the atmosphere, not by the reducer supply from the melt. The project experiments have not detected any input of the zirconium oxidation kinetics into the process chemistry. The completed analysis puts forward a simple analytical model, which gives an explanation of the main features of melt oxidation process. The numerical modeling results are in good agreement with experimental data and theoretical considerations.

  20. Methods for synthesizing metal oxide nanowires

    Science.gov (United States)

    Sunkara, Mahendra Kumar; Kumar, Vivekanand; Kim, Jeong H.; Clark, Ezra Lee

    2016-08-09

    A method of synthesizing a metal oxide nanowire includes the steps of: combining an amount of a transition metal or a transition metal oxide with an amount of an alkali metal compound to produce a mixture; activating a plasma discharge reactor to create a plasma discharge; exposing the mixture to the plasma discharge for a first predetermined time period such that transition metal oxide nanowires are formed; contacting the transition metal oxide nanowires with an acid solution such that an alkali metal ion is exchanged for a hydrogen ion on each of the transition metal oxide nanowires; and exposing the transition metal oxide nanowires to the plasma discharge for a second predetermined time period to thermally anneal the transition metal oxide nanowires. Transition metal oxide nanowires produced using the synthesis methods described herein are also provided.

  1. Method of removing oxides of sulfur and oxides of nitrogen from exhaust gases

    Science.gov (United States)

    Walker, Richard J.

    1986-01-01

    A continuous method is presented for removing both oxides of sulfur and oxides of nitrogen from combustion or exhaust gases with the regeneration of the absorbent. Exhaust gas is cleaned of particulates and HCl by a water scrub prior to contact with a liquid absorbent that includes an aqueous solution of bisulfite and sulfite ions along with a metal chelate, such as, an iron or zinc aminopolycarboxylic acid. Following contact with the combustion gases the spent absorbent is subjected to electrodialysis to transfer bisulfite ions into a sulfuric acid solution while splitting water with hydroxide and hydrogen ion migration to equalize electrical charge. The electrodialysis stack includes alternate layers of anion selective and bipolar membranes. Oxides of nitrogen are removed from the liquid absorbent by air stripping at an elevated temperature and the regenerated liquid absorbent is returned to contact with exhaust gases for removal of sulfur oxides and nitrogen oxides.

  2. Long-Term Stability of Oxide Nanowire Sensors via Heavily Doped Oxide Contact.

    Science.gov (United States)

    Zeng, Hao; Takahashi, Tsunaki; Kanai, Masaki; Zhang, Guozhu; He, Yong; Nagashima, Kazuki; Yanagida, Takeshi

    2017-12-22

    Long-term stability of a chemical sensor is an essential quality for long-term collection of data related to exhaled breath, environmental air, and other sources in the Internet of things (IoT) era. Although an oxide nanowire sensor has shown great potential as a chemical sensor, the long-term stability of sensitivity has not been realized yet due to electrical degradation under harsh sensing conditions. Here, we report a rational concept to accomplish long-term electrical stability of metal oxide nanowire sensors via introduction of a heavily doped metal oxide contact layer. Antimony-doped SnO 2 (ATO) contacts on SnO 2 nanowires show much more stable and lower electrical contact resistance than conventional Ti contacts for high temperature (200 °C) conditions, which are required to operate chemical sensors. The stable and low contact resistance of ATO was confirmed for at least 1960 h under 200 °C in open air. This heavily doped oxide contact enables us to realize the long-term stability of SnO 2 nanowire sensors while maintaining the sensitivity for both NO 2 gas and light (photo) detections. The applicability of our method is confirmed for sensors on a flexible polyethylene naphthalate (PEN) substrate. Since the proposed fundamental concept can be applied to various oxide nanostructures, it will give a foundation for designing long-term stable oxide nanomaterial-based IoT sensors.

  3. Oxidation of diesel soot on binary oxide CuCr(Co)-based monoliths.

    Science.gov (United States)

    Soloviev, Sergiy O; Kapran, Andriy Y; Kurylets, Yaroslava P

    2015-02-01

    Binary oxide systems (CuCr2O4, CuCo2O4), deposited onto cordierite monoliths of honeycomb structure with a second support (finely dispersed Al2O3), were prepared as filters for catalytic combustion of diesel soot using internal combustion engine's gas exhausts (O2, NOx, H2O, CO2) and O3 as oxidizing agents. It is shown that the second support increases soot capacity of aforementioned filters, and causes dispersion of the particles of spinel phases as active components enhancing thereby catalyst activity and selectivity of soot combustion to CO2. Oxidants used can be arranged with reference to decreasing their activity in a following series: O3≫NO2>H2O>NO>O2>CO2. Ozone proved to be the most efficient oxidizing agent: the diesel soot combustion by O3 occurs intensively (in the presence of copper chromite based catalyst) even at closing to ambient temperatures. Results obtained give a basis for the conclusion that using a catalytic coating on soot filters in the form of aforementioned binary oxide systems and ozone as the initiator of the oxidation processes is a promising approach in solving the problem of comprehensive purification of automotive exhaust gases at relatively low temperatures, known as the "cold start" problem. Copyright © 2014. Published by Elsevier B.V.

  4. Manganese Oxidation by Bacteria: Biogeochemical Aspects

    Digital Repository Service at National Institute of Oceanography (India)

    Sujith, P.P.; LokaBharathi, P.A.

    Manganese is an essential trace metal that is not as readily oxidizable like iron. Several bacterial groups posses the ability to oxidize Mn effectively competing with chemical oxidation. The oxides of Mn are the strongest of the oxidants, next...

  5. Zirconium metal-water oxidation kinetics. V. Oxidation of Zircaloy in high pressure steam

    International Nuclear Information System (INIS)

    Pawel, R.E.; Cathcart, J.V.; Campbell, J.J.; Jury, S.H.

    1977-12-01

    A series of scoping tests to determine the influence of steam pressure on the isothermal oxidation kinetics of Zircaloy-4 PWR tubing was undertaken. The oxidation experiments were conducted in flowing steam at 3.45, 6.90, and 10.34 MPa (500, 1000, and 1500 psi) at 905 0 C (1661 0 F), and at 3.45 and 6.90 MPa at 1101 0 C (2014 0 F). A comparison of the results of these experiments with those obtained for oxidation in steam at atmospheric pressure under similar conditions indicated that measurable enhancement of the oxidation rate occurred with increasing pressure at 905 0 C, but not at 1100 0 C

  6. Reduction Behaviors of Carbon Composite Iron Oxide Briquette Under Oxidation Atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ki-Woo; Kim, Kang-Min; Kwon, Jae-Hong; Han, Jeong-Whan [Inha University, Incheon (Korea, Republic of); Son, Sang-Han [POSCO, Pohang (Korea, Republic of)

    2017-01-15

    The carbon composite iron oxide briquette (CCB) is considered a potential solution to the upcoming use of low grade iron resources in the ironmaking process. CCB is able to reduce raw material cost by enabling the use of low grade powdered iron ores and coal. Additionally, the fast reduction of iron oxides by direct contact with coal can be utilized. In this study, the reduction behaviors of CCB were investigated in the temperature range of 200-1200 ℃ under oxidizing atmosphere. Briquettes were prepared by mixing iron ore and coal in a weight ratio of 8:2. Then reduction experiments were carried out in a mixed gas atmosphere of N{sub 2}, O{sub 2}, and CO{sub 2}. Compressive strength tests and quantitative analysis were performed by taking samples at each target temperature. In addition, the reduction degree depending on the reaction time was evaluated by off-gas analysis during the reduction test. It was found that the compressive strength and the metallization degree of the reduced briquettes increased with increases in the reaction temperature and holding time. However, it tended to decrease when the re-oxidation phenomenon was caused by injected oxygen. The degree of reduction reached a maximum value in 26 minutes. Therefore, the re-oxidation phenomenon becomes dominant after 26 minutes.

  7. Death from Nitrous Oxide.

    Science.gov (United States)

    Bäckström, Björn; Johansson, Bengt; Eriksson, Anders

    2015-11-01

    Nitrous oxide is an inflammable gas that gives no smell or taste. It has a history of abuse as long as its clinical use, and deaths, although rare, have been reported. We describe two cases of accidental deaths related to voluntary inhalation of nitrous oxide, both found dead with a gas mask covering the face. In an attempt to find an explanation to why the victims did not react properly to oncoming hypoxia, we performed experiments where a test person was allowed to breath in a closed system, with or without nitrous oxide added. Vital signs and gas concentrations as well as subjective symptoms were recorded. The experiments indicated that the explanation to the fact that neither of the descendents had reacted to oncoming hypoxia and hypercapnia was due to the inhalation of nitrous oxide. This study raises the question whether nitrous oxide really should be easily, commercially available. © 2015 American Academy of Forensic Sciences.

  8. Chemistry of phospholipid oxidation.

    Science.gov (United States)

    Reis, Ana; Spickett, Corinne M

    2012-10-01

    The oxidation of lipids has long been a topic of interest in biological and food sciences, and the fundamental principles of non-enzymatic free radical attack on phospholipids are well established, although questions about detail of the mechanisms remain. The number of end products that are formed following the initiation of phospholipid peroxidation is large, and is continually growing as new structures of oxidized phospholipids are elucidated. Common products are phospholipids with esterified isoprostane-like structures and chain-shortened products containing hydroxy, carbonyl or carboxylic acid groups; the carbonyl-containing compounds are reactive and readily form adducts with proteins and other biomolecules. Phospholipids can also be attacked by reactive nitrogen and chlorine species, further expanding the range of products to nitrated and chlorinated phospholipids. Key to understanding the mechanisms of oxidation is the development of advanced and sensitive technologies that enable structural elucidation. Tandem mass spectrometry has proved invaluable in this respect and is generally the method of choice for structural work. A number of studies have investigated whether individual oxidized phospholipid products occur in vivo, and mass spectrometry techniques have been instrumental in detecting a variety of oxidation products in biological samples such as atherosclerotic plaque material, brain tissue, intestinal tissue and plasma, although relatively few have achieved an absolute quantitative analysis. The levels of oxidized phospholipids in vivo is a critical question, as there is now substantial evidence that many of these compounds are bioactive and could contribute to pathology. The challenges for the future will be to adopt lipidomic approaches to map the profile of oxidized phospholipid formation in different biological conditions, and relate this to their effects in vivo. This article is part of a Special Issue entitled: Oxidized phospholipids

  9. Oxidative stress and pathology in muscular dystrophies: focus on protein thiol oxidation and dysferlinopathies.

    Science.gov (United States)

    Terrill, Jessica R; Radley-Crabb, Hannah G; Iwasaki, Tomohito; Lemckert, Frances A; Arthur, Peter G; Grounds, Miranda D

    2013-09-01

    The muscular dystrophies comprise more than 30 clinical disorders that are characterized by progressive skeletal muscle wasting and degeneration. Although the genetic basis for many of these disorders has been identified, the exact mechanism for pathogenesis generally remains unknown. It is considered that disturbed levels of reactive oxygen species (ROS) contribute to the pathology of many muscular dystrophies. Reactive oxygen species and oxidative stress may cause cellular damage by directly and irreversibly damaging macromolecules such as proteins, membrane lipids and DNA; another major cellular consequence of reactive oxygen species is the reversible modification of protein thiol side chains that may affect many aspects of molecular function. Irreversible oxidative damage of protein and lipids has been widely studied in Duchenne muscular dystrophy, and we have recently identified increased protein thiol oxidation in dystrophic muscles of the mdx mouse model for Duchenne muscular dystrophy. This review evaluates the role of elevated oxidative stress in Duchenne muscular dystrophy and other forms of muscular dystrophies, and presents new data that show significantly increased protein thiol oxidation and high levels of lipofuscin (a measure of cumulative oxidative damage) in dysferlin-deficient muscles of A/J mice at various ages. The significance of this elevated oxidative stress and high levels of reversible thiol oxidation, but minimal myofibre necrosis, is discussed in the context of the disease mechanism for dysferlinopathies, and compared with the situation for dystrophin-deficient mdx mice. © 2013 The Authors Journal compilation © 2013 FEBS.

  10. Nanoroses of nickel oxides: Synthesis, electron tomography study, and application in CO oxidation and energy storage

    KAUST Repository

    Fihri, Aziz

    2012-04-11

    Nickel oxide and mixed-metal oxide structures were fabricated by using microwave irradiation in pure water. The nickel oxide self-assembled into unique rose-shaped nanostructures. These nickel oxide roses were studied by performing electron tomography with virtual cross-sections through the particles to understand their morphology from their interior to their surface. These materials exhibited promising performance as nanocatalysts for CO oxidation and in energy storage devices. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Corrosion behaviour of nanometre sized cerium oxide and titanium oxide incorporated aluminium in NaCl solution

    International Nuclear Information System (INIS)

    Ashraf, P. Muhamed; Edwin, Leela

    2013-01-01

    Highlights: ► Corrosion resistant aluminium incorporated with nano oxides of cerium and titanium. ► 0.2% nano CeO 2 and 0.05% nano TiO 2 showed increased corrosion resistance. ► Nano TiO 2 concentration influenced the optimum performance of the material. ► Comparison of Micro and nano CeO 2 and TiO 2 aluminium showed the latter is best. - Abstract: The study highlights the development of an aluminium matrix composite by incorporating mixture of nanometre sized cerium oxide and titanium oxide in pure aluminium and its corrosion resistance in marine environment. The mixed nanometre sized oxides incorporated aluminium exhibited improved microstructure and excellent corrosion resistance. Corrosion resistance depends on the concentration of nanometre sized titanium oxide. Electrochemical characteristics improved several folds in nanometre sized mixed oxides incorporated aluminium than micrometre sized oxides incorporated aluminium.

  12. Heterogeneous catalysis in the liquid-phase oxidation of olefins--3. The activity of supported vanadium-chromium binary oxide catalyst for the oxidation of cyclohexene

    Energy Technology Data Exchange (ETDEWEB)

    Takehira, K; Hayakawa, T; Ishikawa, T

    1979-03-01

    The activity of supported vanadium-chromium binary oxide catalyst for the oxidation of cyclohexene to 1-cyclohexenyl hydroperoxide, 2-cyclohexene-1-one, 2-cyclohexene-1-ol, and cyclohexene oxide was due to the interaction between the metal oxides and the carriers. The oxidation reaction was carried out in benzene at 60/sup 0/C for four hours with the binary oxide supported on (GAMMA)-alumina or silica; three series of catalysts were prepared by combining the vanadium and chromium oxide components with alumina hydrate or silica sol by a kneading method. The silica-supported catalysts had the greatest activity, the highest being the V/sub 2/O/sub 5//SiO/sub 2/ system, which lost its activity quickly during the reaction. This was followed in activity by the Cr/sub 2/O/sub 3//SiO/sub 2/ system, containing the chromium(V) species. The Cr/sub 2/O/sub 3//Al/sub 2/O/sub 3/ system also had high activity and the chromium(V) species. The vanadium and chromium metal ions are probably coordinated tetrahedrally on the support, and these complexes catalyze cyclohexene autoxidation by decomposing 1-cyclohexenyl hydroperoxide.

  13. Factors controlling the oxide ion conductivity of fluorite and perovskite structured oxides

    DEFF Research Database (Denmark)

    Mogensen, Mogens Bjerg; Lybye, D.; Bonanos, N.

    2004-01-01

    Many metal oxides of fluorite and perovskite related structures are oxide ion conductors, which have practical applications in devices such as oxygen sensors, solid oxide fuel cells (SOFC) and electrolysers. Several structural and thermodynamic parameters such as (1) critical radius of the pathway...... such parameters for fluorite and perovskite oxides by considering their sensitivities to the individual ionic radii. Based on experimental data available in the literature, it is argued that lattice distortion (lattice stress and deviation from cubic symmetry) due to ion radii mismatch determines the ionic...... conductivity to a very large extent, and that lattice distortion is of much greater importance than many other proposed parameters. In case of the perovskites, the charge of the B-site ion is also of major importance. (C) 2004 Published by Elsevier B.V....

  14. [Oxidation behavior and kinetics of representative VOCs emitted from petrochemical industry over CuCeOx composite oxides].

    Science.gov (United States)

    Chen, Chang-Wei; Yu, Yan-Ke; Chen, Jin-Sheng; He, Chi

    2013-12-01

    CuCeOx composite catalysts were synthesized via coprecipitation (COP-CuCeO,) and incipient impregnation (IMP-CuCeOx) methods, respectively. The physicochemical properties of the samples were characterized by XRD, low-temperature N2 sorption, H2-TPR and O2-TPD. The influences of reactant composition and concentration, reaction space velocity, O2 content, H2O concentration, and catalyst type on the oxidation behaviors of benzene, toluene, and n-hexane emitted from petrochemical industry were systematically investigated. In addition, the related kinetic parameters were model fitted. Compared with IMP-CuCeOx, COP-CuCeOx had well-dispersed active phase, better low-temperature reducibility, and more active surface oxygen species. The increase of reactant concentration was unfavorable for toluene oxidation, while the opposite phenomenon could be observed in n-hexane oxidation. The inlet concentration of benzene was irrelevant to its conversion under high oxidation rate. The introduction of benzene obviously inhibited the oxidation of toluene and n-hexane, while the presence of toluene had a positive effect on beuzene conversion. The presence of n-hexane could promote the oxidation of toluene, while toluene had a negative influence on e-hexane oxidation. Both low space velocity and high oxygen concentration were beneficial for the oxidation process, and the variation of oxygen content had negligible effect on n-hexane and henzene oxidation. The presence of H2O noticeably inhibited the oxidation of toluene, while significantly accelerated the oxidation procedure of henzene and n-hexane. COP-CuCeOx had superior catalytic performance for toluene and benzene oxidation, while IMP-CuCeOx showed higher n-hexane oxidation activity under dry condition. The oxidation behaviors under different conditions could be well fitted and predicted by the pseudo first-order kinetic model.

  15. Interface Controlled Oxidation States in Layered Cobalt Oxide Nanoislands on Gold

    DEFF Research Database (Denmark)

    Walton, Alexander; Fester, Jakob; Bajdich, Michal

    2015-01-01

    Layered cobalt oxides have been shown to be highly active catalysts for the oxygen evolution reaction (OER; half of the catalytic “water splitting” reaction), particularly when promoted with gold. However, the surface chemistry of cobalt oxides and in particular the nature of the synergistic effect...

  16. Laccase-Functionalized Graphene Oxide Assemblies as Efficient Nanobiocatalysts for Oxidation Reactions

    NARCIS (Netherlands)

    Patila, Michaela; Kouloumpis, Antonios; Gournis, Dimitrios; Rudolf, Petra; Stamatis, Haralambos

    Multi-layer graphene oxide-enzyme nanoassemblies were prepared through the multi-point covalent immobilization of laccase from Trametes versicolor (TvL) on functionalized graphene oxide (fGO). The catalytic properties of the fGO-TvL nanoassemblies were found to depend on the number of the graphene

  17. Reaction pathways for catalytic gas-phase oxidation of glycerol over mixed metal oxides

    Energy Technology Data Exchange (ETDEWEB)

    Suprun, W.; Glaeser, R.; Papp, H. [Leipzig Univ. (Germany). Inst. of Chemical Technology

    2011-07-01

    Glycerol as a main by-product from bio-diesel manufacture is a cheap raw material with large potential for chemical or biochemical transformations to value-added C3-chemicals. One possible way of glycerol utilization involves its catalytic oxidation to acrylic acid as an alternative to petrochemical routes. However, this catalytic conversion exhibits various problems such as harsh reaction conditions, severe catalyst coking and large amounts of undesired by-products. In this study, the reaction pathways for gas-phase conversion of glycerol over transition metal oxides (Mo, V und W) supported on TiO{sub 2} and SiO{sub 2} were investigated by two methods: (i) steady state experiments of glycerol oxidation and possible reactions intermediates, i.e., acrolein, 3-hydroxy propionaldehyde and acetaldehyde, and (ii) temperature-programmed surface reaction (TPSR) studies of glycerol conversion in the presence and in the absence of gas-phase oxygen. It is shown that the supported W-, V and Mo-oxides possess an ability to catalyze the oxidation of glycerol to acrylic acid. These investigations allowed us to gain a deeper insight into the reaction mechanism. Thus, based on the obtained results, three possible reactions pathways for the selective oxidation of glycerol to acrylic acid on the transition metal-containing catalysts are proposed. The major pathways in presence of molecular oxygen are a fast successive destructive oxidation of glycerol to CO{sub x} and the dehydration of glycerol to acrolein which is a rate-limiting step. (orig.)

  18. Partial oxidation of n- and i-pentane over promoted vanadium-phosphorus oxide catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Zazhigalov, V.A.; Mikhajluk, B.D.; Komashko, G.A. [AN Ukrainskoj SSR, Kiev (Ukraine). Inst. Fizicheskoj Khimii

    1998-12-31

    It is known, that the cost of raw materials for catalytic oxidation processes is about 60% of the product price. Cheap initial compounds to produce variety of products and to replace olefins and aromatic hydrocarbons are paraffins. That is why catalytic systems which could be possibly rather efficient in selective oxidation of paraffin hydrocarbons are under very close investigation now. One of such processes in n-pentane oxidation. The obtained results on n-pentane oxidation over VPO catalysts were quite encouraging in respect of possible reach high selectivity and yield of phthalic anhydride. However, in our work it was shown that the main product of n-pentane oxidation in the presence of VPO catalytic system as well as VPMeO was maleic anhydride. Some later our results were confirmed in, where to grow the selectivity towards phthalic anhydride the Co-additive was introduced. On the basis of the proposal made before on the mechanism of paraffins conversion over the vanadyl pyrophosphate surface with their activation at the first and fourth carbon atoms, we assumed possible methylmaleic (citraconic) anhydride forming at n- and i-pentane oxidation. This assumption has been recently supported by both our and other researchers` experimental results. In it was also hypothized possible mechanistic features for phthalic anhydride forming from n-pentane. The present work deals with the results of n- and i-pentane oxidation over VPO catalysts promoted with Bi, Cs, Te, Zr. (orig.)

  19. Nanostructured manganese oxides as highly active water oxidation catalysts: a boost from manganese precursor chemistry.

    Science.gov (United States)

    Menezes, Prashanth W; Indra, Arindam; Littlewood, Patrick; Schwarze, Michael; Göbel, Caren; Schomäcker, Reinhard; Driess, Matthias

    2014-08-01

    We present a facile synthesis of bioinspired manganese oxides for chemical and photocatalytic water oxidation, starting from a reliable and versatile manganese(II) oxalate single-source precursor (SSP) accessible through an inverse micellar molecular approach. Strikingly, thermal decomposition of the latter precursor in various environments (air, nitrogen, and vacuum) led to the three different mineral phases of bixbyite (Mn2 O3 ), hausmannite (Mn3 O4 ), and manganosite (MnO). Initial chemical water oxidation experiments using ceric ammonium nitrate (CAN) gave the maximum catalytic activity for Mn2 O3 and MnO whereas Mn3 O4 had a limited activity. The substantial increase in the catalytic activity of MnO in chemical water oxidation was demonstrated by the fact that a phase transformation occurs at the surface from nanocrystalline MnO into an amorphous MnOx (1oxidizing agent. Photocatalytic water oxidation in the presence of [Ru(bpy)3 ](2+) (bpy=2,2'-bipyridine) as a sensitizer and peroxodisulfate as an electron acceptor was carried out for all three manganese oxides including the newly formed amorphous MnOx . Both Mn2 O3 and the amorphous MnOx exhibit tremendous enhancement in oxygen evolution during photocatalysis and are much higher in comparison to so far known bioinspired manganese oxides and calcium-manganese oxides. Also, for the first time, a new approach for the representation of activities of water oxidation catalysts has been proposed by determining the amount of accessible manganese centers. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. High-temperature oxidation behavior of dense SiBCN monoliths: Carbon-content dependent oxidation structure, kinetics and mechanisms

    International Nuclear Information System (INIS)

    Li, Daxin; Yang, Zhihua; Jia, Dechang; Wang, Shengjin; Duan, Xiaoming; Zhu, Qishuai; Miao, Yang; Rao, Jiancun; Zhou, Yu

    2017-01-01

    Highlights: •The scale growth for all investigated monoliths at 1500 °C cannot be depicted by a linear or parabolic rate law. •The carbon-rich monoliths oxidize at 1500 °C according to a approximately linear weight loss equation. •The excessive carbon in SiBCN monoliths deteriorates the oxidation resistance. •The oxidation resistance stems from the characteristic oxide structures and increased oxidation resistance of BN(C). -- Abstract: The high temperature oxidation behavior of three SiBCN monoliths: carbon-lean SiBCN with substantial Si metal, carbon-moderate SiBCN and carbon-rich SiBCN with excessive carbon, was investigated at 1500 °C for times up to15 h. Scale growth for carbon-lean and −moderate monoliths at 1500 °C cannot be described by a linear or parabolic rate law, while the carbon-rich monoliths oxidize according to a approximately linear weight loss equation. The microstructures of the oxide scale compose of three distinct layers. The passivating layer of carbon and boron containing amorphous SiO 2 and increased oxidation resistance of BN(C) both benefit the oxidation resistance.

  1. One-pot hydrothermal synthesis of ruthenium oxide nanodots on reduced graphene oxide sheets for supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Chen Yao [Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190 (China); Graduate University of Chinese Academy Sciences, Beijing 100049 (China); Zhang Xiong [Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190 (China); Zhang Dacheng [Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190 (China); Graduate University of Chinese Academy Sciences, Beijing 100049 (China); Ma Yanwei, E-mail: ywma@mail.iee.ac.cn [Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190 (China)

    2012-01-15

    Highlights: > Graphite oxide instead of graphene as precursor has been used to synthesize reduced graphene oxide/ruthenium oxide composites by a hydrothermal treatment. > Using NaOH solution to adjust pH of GO colloids leads to homogeneous ruthenium oxide deposited on reduced graphene oxide sheets. > A maximum capacitance of 471 F g{sup -1} is obtained at 0.5 A g{sup -1} for the composites when loading 40% of RuO{sub 2} and its life retention reaches 92% after 3000 cycles. - Abstract: Ruthenium oxide nanodots have been deposited on reduced graphene oxide (RGO) sheets homogeneously by hydrothermal and annealing methods. Adding NaOH solution in GO colloids prevents the restack and agglomeration of GO sheets when mixed with ruthenium chloride solution. Local crystallization of RuO{sub 2} in the composites is revealed by X-ray diffraction and transmission electron microscopy. The element mapping image demonstrates the uniform distribution of Ru on RGO sheets. Unlike the pure crystalline RuO{sub 2} exhibiting poor electrochemical performance, the composites present superior capacitive properties. The hydrothermal time is optimized and a maximum of 471 F g{sup -1} is measured in the composites at 0.5 A g{sup -1} when loaded with 45 wt% of RuO{sub 2}. After 3000 cycles, its specific capacitance remains 92% of the maximum capacitance. Our results suggest potential application of the reduced graphene oxide/ruthenium oxide composites to supercapacitors.

  2. One-pot hydrothermal synthesis of ruthenium oxide nanodots on reduced graphene oxide sheets for supercapacitors

    International Nuclear Information System (INIS)

    Chen Yao; Zhang Xiong; Zhang Dacheng; Ma Yanwei

    2012-01-01

    Highlights: → Graphite oxide instead of graphene as precursor has been used to synthesize reduced graphene oxide/ruthenium oxide composites by a hydrothermal treatment. → Using NaOH solution to adjust pH of GO colloids leads to homogeneous ruthenium oxide deposited on reduced graphene oxide sheets. → A maximum capacitance of 471 F g -1 is obtained at 0.5 A g -1 for the composites when loading 40% of RuO 2 and its life retention reaches 92% after 3000 cycles. - Abstract: Ruthenium oxide nanodots have been deposited on reduced graphene oxide (RGO) sheets homogeneously by hydrothermal and annealing methods. Adding NaOH solution in GO colloids prevents the restack and agglomeration of GO sheets when mixed with ruthenium chloride solution. Local crystallization of RuO 2 in the composites is revealed by X-ray diffraction and transmission electron microscopy. The element mapping image demonstrates the uniform distribution of Ru on RGO sheets. Unlike the pure crystalline RuO 2 exhibiting poor electrochemical performance, the composites present superior capacitive properties. The hydrothermal time is optimized and a maximum of 471 F g -1 is measured in the composites at 0.5 A g -1 when loaded with 45 wt% of RuO 2 . After 3000 cycles, its specific capacitance remains 92% of the maximum capacitance. Our results suggest potential application of the reduced graphene oxide/ruthenium oxide composites to supercapacitors.

  3. Zircaloy oxidation studies

    International Nuclear Information System (INIS)

    Prater, J.T.; Beauchamp, R.H.; Saenz, N.T.

    1985-06-01

    The oxidation kinetics of Zircaloy-4 in steam have been determined at 1300-2400 0 C. Growth of the ZrO 2 and α-Zr layers display parabolic behavior over the entire temperature range studied. A discontinuity in the oxidation kinetics at 1510 0 C causes rates to increase above those previously established by the Baker-Just relationship. This increase coincides with the tetragonal-to-cubic phase transformation in ZrO/sub 2-x/. No discontinuity in the oxide growth rate is observed upon melting of Zr(0). The effects of temperature gradients have been taken into account and corrected values representative of near-isothermal conditions have been computed

  4. Transparent conducting oxides and production thereof

    Science.gov (United States)

    Gessert, Timothy A.; Yoshida, Yuki; Coutts, Timothy J.

    2014-06-10

    Transparent conducting oxides and production thereof are disclosed. An exemplary method of producing a transparent conducting oxide (TCO) material may comprise: providing a TCO target doped with either a high-permittivity oxide or a low-permittivity oxide in a process chamber. The method may also comprise depositing a metal oxide on the target in the process chamber to form a thin film having enhanced optical properties without substantially decreasing electrical quality.

  5. Magnetic composites based on hybrid spheres of aluminum oxide and superparamagnetic nanoparticles of iron oxides

    International Nuclear Information System (INIS)

    Braga, Tiago P.; Vasconcelos, Igor F.; Sasaki, Jose M.; Fabris, J.D.; Oliveira, Diana Q.L. de; Valentini, Antoninho

    2010-01-01

    Materials containing hybrid spheres of aluminum oxide and superparamagnetic nanoparticles of iron oxides were obtained from a chemical precursor prepared by admixing chitosan and iron and aluminum hydroxides. The oxides were first characterized with scanning electron microscopy, X-ray diffraction, and Moessbauer spectroscopy. Scanning electron microscopy micrographs showed the size distribution of the resulting spheres to be highly homogeneous. The occurrence of nano-composites containing aluminum oxides and iron oxides was confirmed from powder X-ray diffraction patterns; except for the sample with no aluminum, the superparamagnetic relaxation due to iron oxide particles were observed from Moessbauer spectra obtained at 298 and 110 K; the onset six line-spectrum collected at 20 K indicates a magnetic ordering related to the blocking relaxation effect for significant portion of small spheres in the sample with a molar ratio Al:Fe of 2:1.

  6. Dietary oxidized poultry offal fat: broiler performance and oxidative stability of thigh meat during chilled storage

    Directory of Open Access Journals (Sweden)

    AMC Racanicci

    2008-03-01

    Full Text Available Two experiments were conducted to evaluate the effects of dietary oxidized poultry offal fat on the performance of broilers and on the oxidative stability of dark chicken meat. One hundred and sixty male chicks were fed a corn-soybean meal diet containing 4% fresh or oxidized poultry fat from 10 to 47 days of age. Fresh fat was stored frozen until diets were produced, and oxidized fat was obtained by electrical heating (110 to 120 ºC. Birds were slaughtered at 47 days of age, and carcass characteristics were measured. Skinless and deboned thigh meat was stored chilled during 12 days, and samples were periodically collected to assess their quality and oxidative stability. Dietary oxidized fat did not affect bird performance or carcass characteristics. During chilled storage, meat color (L*, a* and b* was not affected by dietary treatments; however, TBARS (Thiobarbituric Acid Reactive Substances values were higher (P<0.05 in thigh meat from chickens fed the oxidized fat, indicating that oxidative stability was adversely affected.

  7. Synthesis of vertically aligned metal oxide nanostructures

    KAUST Repository

    Roqan, Iman S.

    2016-03-03

    Metal oxide nanostructure and methods of making metal oxide nanostructures are provided. The metal oxide nanostructures can be 1 -dimensional nanostructures such as nanowires, nanofibers, or nanotubes. The metal oxide nanostructures can be doped or undoped metal oxides. The metal oxide nanostructures can be deposited onto a variety of substrates. The deposition can be performed without high pressures and without the need for seed catalysts on the substrate. The deposition can be performed by laser ablation of a target including a metal oxide and, optionally, a dopant. In some embodiments zinc oxide nanostructures are deposited onto a substrate by pulsed laser deposition of a zinc oxide target using an excimer laser emitting UV radiation. The zinc oxide nanostructure can be doped with a rare earth metal such as gadolinium. The metal oxide nanostructures can be used in many devices including light-emitting diodes and solar cells.

  8. Electron donating and acid-base properties of cerium oxide and its mixed oxides with alumina

    International Nuclear Information System (INIS)

    Sugunan, S.; Jalaja, J.M.

    1994-01-01

    The electron donating properties of cerium oxide activated at 300, 500 and 800 degC and of its mixed oxides with alumina were examined based on the adsorption of electron acceptors exhibiting different electron affinities. The surface acidity/basicity of the oxides was determined by titrimetry; the H 0,max values are given. The limit of electron transfer from the oxide surface lies within the region of 1.77 and 2.40 eV in terms of the electron affinity of the electron acceptor. Cerium oxide promotes the electron donor nature of alumina while leaving the limit of electron transfer unchanged. 2 tabs., 4 figs., 13 refs

  9. Trends in reactivity of oxides

    DEFF Research Database (Denmark)

    Toftelund, Anja

    The results in this thesis are based on Density Functional Theory calculations. The catalytic activity of oxides and other compound materials are investigated. It is found that the adsorption energy of the molecules NH2, NH, OH and SH on transition metal nitride, oxide and sulfide surfaces scales......, and I) and OH on a wide range of rutile oxide surfaces. Furthermore, Brønsted-Evans-Polanyi (BEP) relations are found for the adsorption of a large number of molecules (including Cl, Br and I) on transition metal oxides. In these relations the activation energies scale linearly with the dissociative...... chemisorption energies. It turns out that the BEP relation for rutile oxides is almost coinciding with the dissociation line, i.e. no barrier exists for the reactive surfaces. The heterogeneous catalytic oxidation of hydrogen halides (HCl, HBr, and HI) is investigated. A micro-kinetic model is solved...

  10. Vanadium oxide monolayer catalysts : The vapor-phase oxidation of methanol

    NARCIS (Netherlands)

    Roozeboom, Fred; Cordingley, Peter D.; Gellings, P.J.

    1981-01-01

    The oxidation of methanol over vanadium oxide, unsupported and applied as a monolayer on γ-Al2O3, CeO2, TiO2, and ZrO2, was studied between 100 and 400 °C in a continuous-flow reactor. At temperatures from 150 to about 250 °C two main reactions take place, (a) dehydration of methanol to dimethyl

  11. Oxidative stress induced by cerium oxide nanoparticles in cultured BEAS-2B cells

    International Nuclear Information System (INIS)

    Park, Eun-Jung; Choi, Jinhee; Park, Young-Kwon; Park, Kwangsik

    2008-01-01

    Cerium oxide nanoparticles of different sizes (15, 25, 30, 45 nm) were prepared by the supercritical synthesis method, and cytotoxicity was evaluated using cultured human lung epithelial cells (BEAS-2B). Exposure of the cultured cells to nanoparticles (5, 10, 20, 40 μg/ml) led to cell death, ROS increase, GSH decrease, and the inductions of oxidative stress-related genes such as heme oxygenase-1, catalase, glutathione S-transferase, and thioredoxin reductase. The increased ROS by cerium oxide nanoparticles triggered the activation of cytosolic caspase-3 and chromatin condensation, which means that cerium oxide nanoparticles exert cytotoxicity by an apoptotic process. Uptake of the nanoparticles to the cultured cells was also tested. It was observed that cerium oxide nanoparticles penetrated into the cytoplasm and located in the peri-region of the nucleus as aggregated particles, which may induce the direct interaction between nanoparticles and cellular molecules to cause adverse cellular responses

  12. Advanced methods for the treatment of organic aqueous wastes: wet air oxidation and wet peroxide oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Debellefontaine, Hubert; Chakchouk, Mehrez; Foussard, Jean Noel [Institut National des Sciences Appliquees (INSA), 31 - Toulouse (France). Dept. de Genie des Procedes Industriels; Tissot, Daniel; Striolo, Phillipe [IDE Environnement S.A., Toulouse (France)

    1994-12-31

    There is a growing concern about the problems of wastes elimination. Various oxidation techniques are suited for elimination of organic aqueous wastes, however, because of the environmental drawbacks of incineration, liquid phase oxidation should be preferred. `Wet Air Oxidation` and `Wet Peroxide Oxidation`are alternative processes which are discussed in this paper. 17 refs., 13 figs., 4 tabs.

  13. Advanced methods for the treatment of organic aqueous wastes: wet air oxidation and wet peroxide oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Debellefontaine, Hubert; Chakchouk, Mehrez; Foussard, Jean Noel [Institut National des Sciences Appliquees (INSA), 31 - Toulouse (France). Dept. de Genie des Procedes Industriels; Tissot, Daniel; Striolo, Phillipe [IDE Environnement S.A., Toulouse (France)

    1993-12-31

    There is a growing concern about the problems of wastes elimination. Various oxidation techniques are suited for elimination of organic aqueous wastes, however, because of the environmental drawbacks of incineration, liquid phase oxidation should be preferred. `Wet Air Oxidation` and `Wet Peroxide Oxidation`are alternative processes which are discussed in this paper. 17 refs., 13 figs., 4 tabs.

  14. Unprecedented Selective Oxidation of Styrene Derivatives using a Supported Iron Oxide Nanocatalyst in Aqueous Medium

    Science.gov (United States)

    Iron oxide nanoparticles supported on mesoporous silica-type materials have been successfully utilized in the aqueous selective oxidation of alkenes under mild conditions using hydrogen peroxide as a green oxidant. Catalysts could be easily recovered after completion of the reac...

  15. Modeling of Oxidized PTH (oxPTH) and Non-oxidized PTH (n-oxPTH) Receptor Binding and Relationship of Oxidized to Non-Oxidized PTH in Children with Chronic Renal Failure, Adult Patients on Hemodialysis and Kidney Transplant Recipients

    DEFF Research Database (Denmark)

    Hocher, Berthold; Oberthür, Dominik; Slowinski, Torsten

    2013-01-01

    Background: The biological properties of oxidized and non-oxidized PTH are substantially different. Oxidized PTH (oxPTH) loses its PTH receptor-stimulating properties, whereas non-oxidized PTH (n-oxPTH) is a full agonist of the receptor. This was described in more than 20 well published studies i......PTH measures describes most likely oxidative stress in patients with renal failure rather than the PTH hormone status. This, however, needs to be demonstrated in further clinical studies. © 2013 S. Karger AG, Basel......., we performed modeling of the interaction of either oxPTH or n-oxPTH with the PTH receptor using biophysical structure approaches. Results: The children had the highest mean as well as maximum n-oxPTH concentrations as compared to adult patients (both patients on dialysis as well as kidney transplant......-oxPTH. This indicated that PTH oxidation may induce refolding of PTH and hence alters PTH-PTH receptor interaction via oxidation induced three-dimensional structure alteration of PTH. Conclusion: A huge proportion of circulating PTH measured by current state-of-the-art assay systems is oxidized and thus...

  16. Radiolytic oxidation

    International Nuclear Information System (INIS)

    Burns, W.G.; Ewart, F.T.; Hobley, J.; Smith, A.J.; Walters, W.S.; Williams, S.J.

    1991-01-01

    Work under the Radiolytic Oxidation Contract from 1986 until April 1989 is reported. The effects of alpha- and gamma-irradiation on the chemistries of plutonium, neptunium and technetium, under conditions representative of the near fields of intermediate and high level waste repositories, were investigated. Gamma-radiolysis of Np (IV) results in oxidation in solutions below pH 12. Solutions of Tc (VII) are reduced to Tc (IV) by gamma-irradiation in contact with blast furnace slag/ordinary Portland cement under an inert atmosphere but not when in contact with pulverized fuel ash/ordinary Portland cement. Tc (IV) is shown to be susceptible to oxidation by the products of the alpha-radiolysis of water. The results of 'overall effects' experiments, which combined representative components of typical ILW or HLW near fields, supported these observations and also showed enhanced plutonium concentrations in alpha-irradiated, HLW simulations. Mathematical models of the behaviour of plutonium and neptunium during gamma-radiolysis have been developed and indicate that oxidation to Pu (VI) is possible at dose rates typical of those expected for HLW. Simulations at ILW dose rates have indicated some effect upon the speciation of neptunium. Laboratory studies of the gamma-irradiation of Np (IV) in bentonite-equilibrated water have also been modelled. Computer code used: PHREEQE, 8 Figs.; 48 Tabs.; 38 refs

  17. Oxidation and photo-oxidation of water on TiO2 surface

    DEFF Research Database (Denmark)

    Valdes, A.; Qu, Z.W.; Kroes, G.J.

    2008-01-01

    The oxidation and photo-oxidation of water on the rutile TiO2(110) surface is investigated using density functional theory (DFT) calculations. We investigate the relative stability of different surface terminations of TiO2 interacting with H2O and analyze the overpotential needed for the electrol...

  18. Method for hot pressing beryllium oxide articles

    Science.gov (United States)

    Ballard, Ambrose H.; Godfrey, Jr., Thomas G.; Mowery, Erb H.

    1988-01-01

    The hot pressing of beryllium oxide powder into high density compacts with little or no density gradients is achieved by employing a homogeneous blend of beryllium oxide powder with a lithium oxide sintering agent. The lithium oxide sintering agent is uniformly dispersed throughout the beryllium oxide powder by mixing lithium hydroxide in an aqueous solution with beryllium oxide powder. The lithium hydroxide is converted in situ to lithium carbonate by contacting or flooding the beryllium oxide-lithium hydroxide blend with a stream of carbon dioxide. The lithium carbonate is converted to lithium oxide while remaining fixed to the beryllium oxide particles during the hot pressing step to assure uniform density throughout the compact.

  19. Effects of interfacial Fe electronic structures on magnetic and electronic transport properties in oxide/NiFe/oxide heterostructures

    International Nuclear Information System (INIS)

    Liu, Qianqian; Chen, Xi; Zhang, Jing-Yan; Yang, Meiyin; Li, Xu-Jing; Jiang, Shao-Long; Liu, Yi-Wei; Cao, Yi; Wu, Zheng-Long; Feng, Chun; Ding, Lei; Yu, Guang-Hua

    2015-01-01

    Highlights: • The magnetic and transport properties of oxide/NiFe/oxide films were studied. • The oxide (SiO 2 , MgO and HfO 2 ) has different elemental electronegativity. • Redox reaction at different NiFe/oxide interface is dependent on the oxide layer. • Different interfacial electronic structures shown by XPS influence the properties. - Abstract: We report that the magnetic and electronic transport properties in oxide/NiFe(2 nm)/oxide film (oxide = SiO 2 , MgO or HfO 2 ) are strongly influenced by the electronic structure of NiFe/oxide interface. Magnetic measurements show that there exist magnetic dead layers in the SiO 2 sandwiched film and MgO sandwiched film, whereas there is no magnetic dead layer in the HfO 2 sandwiched film. Furthermore, in the ultrathin SiO 2 sandwiched film no magnetoresistance (MR) is detected, while in the ultrathin MgO sandwiched film and HfO 2 sandwiched film the MR ratios reach 0.35% and 0.88%, respectively. The investigation by X-ray photoelectron spectroscopy reveals that the distinct interfacial redox reactions, which are dependent on the oxide layers, lead to the variation of magnetic and transport properties in different oxide/NiFe/oxide heterostructures

  20. Oxidative Stress to the Cornea, Changes in Corneal Optical Properties, and Advances in Treatment of Corneal Oxidative Injuries

    Directory of Open Access Journals (Sweden)

    Cestmir Cejka

    2015-01-01

    Full Text Available Oxidative stress is involved in many ocular diseases and injuries. The imbalance between oxidants and antioxidants in favour of oxidants (oxidative stress leads to the damage and may be highly involved in ocular aging processes. The anterior eye segment and mainly the cornea are directly exposed to noxae of external environment, such as air pollution, radiation, cigarette smoke, vapors or gases from household cleaning products, chemical burns from splashes of industrial chemicals, and danger from potential oxidative damage evoked by them. Oxidative stress may initiate or develop ocular injury resulting in decreased visual acuity or even vision loss. The role of oxidative stress in the pathogenesis of ocular diseases with particular attention to oxidative stress in the cornea and changes in corneal optical properties are discussed. Advances in the treatment of corneal oxidative injuries or diseases are shown.

  1. Viscous properties of aluminum oxide nanotubes and aluminium oxide nanoparticles - silicone oil suspensions

    Science.gov (United States)

    Thapa, Ram; French, Steven; Delgado, Adrian; Ramos, Carlos; Gutierrez, Jose; Chipara, Mircea; Lozano, Karen

    2010-03-01

    Electrorheological (ER) fluids consisting of γ-aluminum oxide nanotubes and γ-aluminum oxide nanoparticles dispersed within silicone oil were prepared. The relationship between shear stress and shear rate was measured and theoretically simulated by using an extended Bingham model for both the rheological and electrorheological features of these systems. Shear stress and viscosity showed a sharp increase for the aluminum oxide nanotubes suspensions subjected to applied electric fields whereas aluminum oxide nanoparticles suspensions showed a moderate change. It was found that the transition from liquid to solid state (mediated by the applied electric field) can be described by a power law and that for low applied voltages the relationship is almost linear.

  2. Studies of physicochemical properties of graphite oxide and thermally exfoliated/reduced graphene oxide

    Directory of Open Access Journals (Sweden)

    Drewniak Sabina Elżbieta

    2015-12-01

    Full Text Available The aim of the experimental research studies was to determine some electrical properties of graphite oxide and thermally exfoliated/reduced graphene oxide. The authors tried to interpret the obtained physicochemical results. For that purpose, both resistance measurements and investigation studies were carried out in order to characterize the samples. The resistance was measured at various temperatures in the course of composition changes of gas atmospheres (which surround the samples. The studies were also supported by such methods as: scanning electron microscopy (SEM, Raman spectroscopy (RS, atomic force microscopy (AFM and thermogravimetry (TG. Moreover, during the experiments also the elemental analyses (EA of the tested samples (graphite oxide and thermally exfoliated/reduced graphene oxide were performed.

  3. Mesoporous Transition Metal Oxides for Supercapacitors.

    Science.gov (United States)

    Wang, Yan; Guo, Jin; Wang, Tingfeng; Shao, Junfeng; Wang, Dong; Yang, Ying-Wei

    2015-10-14

    Recently, transition metal oxides, such as ruthenium oxide (RuO₂), manganese dioxide (MnO₂), nickel oxides (NiO) and cobalt oxide (Co₃O₄), have been widely investigated as electrode materials for pseudo-capacitors. In particular, these metal oxides with mesoporous structures have become very hot nanomaterials in the field of supercapacitors owing to their large specific surface areas and suitable pore size distributions. The high specific capacities of these mesoporous metal oxides are resulted from the effective contacts between electrode materials and electrolytes as well as fast transportation of ions and electrons in the bulk of electrode and at the interface of electrode and electrolyte. During the past decade, many achievements on mesoporous transition metal oxides have been made. In this mini-review, we select several typical nanomaterials, such as RuO₂, MnO₂, NiO, Co₃O₄ and nickel cobaltite (NiCo₂O₄), and briefly summarize the recent research progress of these mesoporous transition metal oxides-based electrodes in the field of supercapacitors.

  4. Direct comparison of the electrical properties in metal/oxide/nitride/oxide/silicon and metal/aluminum oxide/nitride/oxide/silicon capacitors with equivalent oxide thicknesses

    Energy Technology Data Exchange (ETDEWEB)

    An, Ho-Myoung; Seo, Yu Jeong; Kim, Hee Dong; Kim, Kyoung Chan; Kim, Jong-Guk [School of Electrical Engineering, Korea University, Seoul 136-713 (Korea, Republic of); Cho, Won-Ju; Koh, Jung-Hyuk [Department of Electronic Materials Engineering, Kwangwoon University, Seoul 139-701 (Korea, Republic of); Sung, Yun Mo [Department of Materials and Science Engineering, Korea University, Seoul 136-713 (Korea, Republic of); Kim, Tae Geun, E-mail: tgkim1@korea.ac.k [School of Electrical Engineering, Korea University, Seoul 136-713 (Korea, Republic of)

    2009-07-31

    We examine the electrical properties of metal/oxide/nitride/oxide/silicon (MONOS) capacitors with two different blocking oxides, SiO{sub 2} and Al{sub 2}O{sub 3}, under the influence of the same electric field. The thickness of the Al{sub 2}O{sub 3} layer is set to 150 A, which is electrically equivalent to a thickness of the SiO{sub 2} layer of 65 A, in the MONOS structure for this purpose. The capacitor with the Al{sub 2}O{sub 3} blocking layer shows a larger capacitance-voltage memory window of 8.6 V, lower program voltage of 7 V, faster program/erase speeds of 10 ms/1 {mu}s, lower leakage current of 100 pA and longer data retention than the one with the SiO{sub 2} blocking layer does. These improvements are attributed to the suppression of the carrier transport to the gate electrode afforded by the use of an Al{sub 2}O{sub 3} blocking layer physically thicker than the SiO{sub 2} one, as well as the effective charge-trapping by Al{sub 2}O{sub 3} at the deep energy levels in the nitride layer.

  5. Graphene oxide and H2 production from bioelectrochemical graphite oxidation.

    Science.gov (United States)

    Lu, Lu; Zeng, Cuiping; Wang, Luda; Yin, Xiaobo; Jin, Song; Lu, Anhuai; Jason Ren, Zhiyong

    2015-11-17

    Graphene oxide (GO) is an emerging material for energy and environmental applications, but it has been primarily produced using chemical processes involving high energy consumption and hazardous chemicals. In this study, we reported a new bioelectrochemical method to produce GO from graphite under ambient conditions without chemical amendments, value-added organic compounds and high rate H2 were also produced. Compared with abiotic electrochemical electrolysis control, the microbial assisted graphite oxidation produced high rate of graphite oxide and graphene oxide (BEGO) sheets, CO2, and current at lower applied voltage. The resultant electrons are transferred to a biocathode, where H2 and organic compounds are produced by microbial reduction of protons and CO2, respectively, a process known as microbial electrosynthesis (MES). Pseudomonas is the dominant population on the anode, while abundant anaerobic solvent-producing bacteria Clostridium carboxidivorans is likely responsible for electrosynthesis on the cathode. Oxygen production through water electrolysis was not detected on the anode due to the presence of facultative and aerobic bacteria as O2 sinkers. This new method provides a sustainable route for producing graphene materials and renewable H2 at low cost, and it may stimulate a new area of research in MES.

  6. Platinized titanium dioxide electrodes for methanol oxidation and photo-oxidation

    Directory of Open Access Journals (Sweden)

    IOANNIS POULIOS

    2012-11-01

    Full Text Available Platinized deposits have been formed on TiO2 particulate films supported on Ti substrates, by means of galvanic replacement of pre-deposited metallic Cu and subsequent immersion of the Cu/TiO2 coatings into a chloroplatinic acid solution. The spontaneous replacement of Cu by Pt results in Pt(Cu/TiO2/Ti electrodes. Both the platinized and the precursor TiO2/Ti electrodes have been characterized by SEM micro­scopy/EDS spectroscopy, their surface electrochemistry has been assessed by cyclic voltammetry in the dark and their photoelectrochemical properties by photovolta­m­metry under UV illumination. It has been found that, although platinized rutile-rich electrodes exhibit typical Pt surface electrochemistry, the anatase-rich electrodes show only traces of oxide formation and stripping. The latter has been translated to a suppression of methanol oxidation at anatase-rich electrodes. On the contrary, methanol oxidation at platinized rutile-rich electrodes occurs at significant rates and can be further enhanced upon UV illumination, as a result of Pt and TiO2 synergism in the photoelectrochemical oxidation of methanol.

  7. Doxorubicin-loaded micelles of reverse poly(butylene oxide)-poly(ethylene oxide)-poly(butylene oxide) block copolymers as efficient "active" chemotherapeutic agents.

    Science.gov (United States)

    Cambón, A; Rey-Rico, A; Mistry, D; Brea, J; Loza, M I; Attwood, D; Barbosa, S; Alvarez-Lorenzo, C; Concheiro, A; Taboada, P; Mosquera, V

    2013-03-10

    Five reverse poly(butylene oxide)-poly(ethylene oxide)-poly(butylene oxide) block copolymers, BOnEOmBOn, with BO ranging from 8 to 21 units and EO from 90 to 411 were synthesized and evaluated as efficient chemotherapeutic drug delivery nanocarriers and inhibitors of the P-glycoprotein (P-gp) efflux pump in a multidrug resistant (MDR) cell line. The copolymers were obtained by reverse polymerization of poly(butylene oxide), which avoids transfer reaction and widening of the EO block distribution, commonly found in commercial poly(ethylene oxide)-poly(propylene oxide) block copolymers (poloxamers). BOnEOmBOn copolymers formed spherical micelles of 10-40 nm diameter at lower concentrations (one order of magnitude) than those of equivalent poloxamers. The influence of copolymer block lengths and BO/EO ratios on the solubilization capacity and protective environment for doxorubicin (DOXO) was investigated. Micelles showed drug loading capacity ranging from ca. 0.04% to 1.5%, more than 150 times the aqueous solubility of DOXO, and protected the cargo from hydrolysis for more than a month due to their greater colloidal stability in solution. Drug release profiles at various pHs, and the cytocompatibility and cytotoxicity of the DOXO-loaded micelles were assessed in vitro. DOXO loaded in the polymeric micelles accumulated more slowly inside the cells than free DOXO due to its sustained release. All copolymers were found to be cytocompatible, with viability extents larger than 95%. In addition, the cytotoxicity of DOXO-loaded micelles was higher than that observed for free drug solutions in a MDR ovarian NCI-ADR-RES cell line which overexpressed P-gp. The inhibition of the P-gp efflux pump by some BOnEOmBOn copolymers, similar to that measured for the common P-gp inhibitor verapamil, favored the retention of DOXO inside the cell increasing its cytotoxic activity. Therefore, poly(butylene oxide)-poly(ethylene oxide) block copolymers offer interesting features as cell

  8. Cost and Performance Assessment of In-situ Chemical Oxidation for Intermittent and Continuous Oxidant Injection

    Science.gov (United States)

    Kim, U.; Parker, J.; Borden, R. C.

    2015-12-01

    In situ chemical oxidation (ISCO) is a popular remediation technology that involves injection of chemical oxidant into groundwater to destroy dissolved and non-aqueous liquid phase contaminants. Depending on site conditions, oxidant can be injected into the contaminated subsurface periodically (intermittently) or continuously. A common approach is to intermittently inject oxidant into a network of wells over a period long enough to emplace oxidant over a target treatment volume (referred to ISCO-int). The injection phase is followed by a passive phase when the oxidant is allowed to react with contaminants and natural oxygen demand (NOD) and to migrate under natural hydraulic gradients. This process may be repeated multiple times until termination criteria are met. Recently, some practitioners have adopted an alternative approach in which oxidant is injected continuously with extraction wells recovering unreacted oxidant to recycle with additional makeup oxidant to maintain its constant concentration (referred to ISCO-cont). Each method has certain advantages and disadvantages. This study numerically evaluates those two ISCO practices in terms of remediation costs and performance based on multiple equi-probable parameter sets. Stochastic cost optimization toolbox (SCOToolkit) is used for this purpose. SCOToolkit is an integrated semi-analytical model for contaminant transport and remediation (e.g., thermal source treatment, ISCO, electron donor injections, permeable reactive barriers) enabling inverse solution and Monte Carlo simulations. Four different aquifer settings, slow and fast Darcy velocities combined with low and high NOD conditions, are used for the evaluation. Preliminary results showed that ISCO-cont is effective for a full scale application without large investment while ISCO-int is more efficient to utilize oxidant in well-characterized sites. Pros and cons of each approach are discussed for the practical use of ISCO for various site conditions.

  9. Catalytic activity of metall-like carbides in carbon oxide oxidation reaction

    International Nuclear Information System (INIS)

    Kharlamov, A.I.; Kosolapova, T.Ya.; Rafal, A.N.; Kirillova, N.V.

    1980-01-01

    Kinetics of carbon oxide oxidation upon carbides of hafnium, niobium, tantalum, molybdenum, zirconium and chromium is studied. Probable mechanism of the catalysts action is suggested. The established character of the change of the carbide catalytic activity is explained by the change of d-electron contribution to the metal-metal interaction

  10. Non-equilibrium oxidation states of zirconium during early stages of metal oxidation

    International Nuclear Information System (INIS)

    Ma, Wen; Yildiz, Bilge; Herbert, F. William; Senanayake, Sanjaya D.

    2015-01-01

    The chemical state of Zr during the initial, self-limiting stage of oxidation on single crystal zirconium (0001), with oxide thickness on the order of 1 nm, was probed by synchrotron x-ray photoelectron spectroscopy. Quantitative analysis of the Zr 3d spectrum by the spectrum reconstruction method demonstrated the formation of Zr 1+ , Zr 2+ , and Zr 3+ as non-equilibrium oxidation states, in addition to Zr 4+ in the stoichiometric ZrO 2 . This finding resolves the long-debated question of whether it is possible to form any valence states between Zr 0 and Zr 4+ at the metal-oxide interface. The presence of local strong electric fields and the minimization of interfacial energy are assessed and demonstrated as mechanisms that can drive the formation of these non-equilibrium valence states of Zr

  11. Passive smoking reduces and vitamin C increases exercise-induced oxidative stress: does this make passive smoking an anti-oxidant and vitamin C a pro-oxidant stimulus?

    Science.gov (United States)

    Theodorou, Anastasios A; Paschalis, Vassilis; Kyparos, Antonios; Panayiotou, George; Nikolaidis, Michalis G

    2014-11-07

    The current interpretative framework states that, for a certain experimental treatment (usually a chemical substance) to be classified as "anti-oxidant", it must possess the property of reducing (or even nullifying) exercise-induced oxidative stress. The aim of the study was to compare side by side, in the same experimental setup, redox biomarkers responses to an identical acute eccentric exercise session, before and after chronic passive smoking (considered a pro-oxidant stimulus) or vitamin C supplementation (considered an anti-oxidant stimulus). Twenty men were randomly assigned into either passive smoking or vitamin C group. All participants performed two acute eccentric exercise sessions, one before and one after either exposure to passive smoking or vitamin C supplementation for 12 days. Vitamin C, oxidant biomarkers (F2-isoprostanes and protein carbonyls) and the non-enzymatic antioxidant (glutathione) were measured, before and after passive smoking, vitamin C supplementation or exercise. It was found that chronic exposure to passive smoking increased the level of F2-isoprostanes and decreased the level of glutathione at rest, resulting in minimal increase or absence of oxidative stress after exercise. Conversely, chronic supplementation with vitamin C decreased the level of F2-isoprostanes and increased the level of glutathione at rest, resulting in marked exercise-induced oxidative stress. Contrary to the current scientific consensus, our results show that, when a pro-oxidant stimulus is chronically delivered, it is more likely that oxidative stress induced by subsequent exercise is decreased and not increased. Reversely, it is more likely to find greater exercise-induced oxidative stress after previous exposure to an anti-oxidant stimulus. We believe that the proposed framework will be a useful tool to reach more pragmatic explanations of redox biology phenomena. Copyright © 2014 Elsevier Inc. All rights reserved.

  12. The effect of substrate texture and oxidation temperature on oxide texture development in zirconium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Garner, A., E-mail: alistair.garner@manchester.ac.uk [Materials Performance Centre, University of Manchester, Grosvenor Street, Manchester, M17HS (United Kingdom); Frankel, P. [Materials Performance Centre, University of Manchester, Grosvenor Street, Manchester, M17HS (United Kingdom); Partezana, J. [Westinghouse Electric Company, 1332 Beulah Road, Pittsburgh, PA 15235 (United States); Preuss, M. [Materials Performance Centre, University of Manchester, Grosvenor Street, Manchester, M17HS (United Kingdom)

    2017-02-15

    During corrosion of zirconium alloys a highly textured oxide is formed, the degree of this preferred orientation has previously been shown to be an important factor in determining the corrosion behaviour of these alloys. Two distinct experiments were designed in order to investigate the origin of this oxide texture development on two commercial alloys. Firstly, sheet samples of Zircaloy-4 were oxidised between 500 and 800 °C in air. The resulting monoclinic oxide texture strength was observed to decrease with increasing oxidation temperature. In a second experiment, orthogonal faces of Low Tin ZIRLO{sub ™} were oxidised in 360 °C water, providing different substrate textures but identical microstructures. The substrate texture was observed to have a negligible effect on the corrosion performance whilst the major orientation of both oxide phases was found to be independent of substrate orientation. It is concluded that the main driving force for oxide texture development in single-phase zirconium alloys is the compressive stress caused by the Zr−ZrO{sub 2} transformation. - Highlights: • Substrate orientation does not significantly affect oxide texture development. • Corrosion performance is independent of substrate texture. • Monoclinic oxide texture strength decreases with increasing oxidation temperature. • The main driving force for texture development is the oxidation-induced stress.

  13. Accelerated oxidation processes is biodiesel

    Energy Technology Data Exchange (ETDEWEB)

    Canakci, M.; Monyem, A.; Van Gerpen, J.

    1999-12-01

    Biodiesel is an alternative fuel for diesel engines that can be produced from renewable feedstocks such as vegetable oil and animal fats. These feedstocks are reacted with an alcohol to produce alkyl monoesters that can be used in conventional diesel engines with little or no modification. Biodiesel, especially if produced from highly unsaturated oils, oxidizes more rapidly than diesel fuel. This article reports the results of experiments to track the chemical and physical changes that occur in biodiesel as it oxidizes. These results show the impact of time, oxygen flow rate, temperature, metals, and feedstock type on the rate of oxidation. Blending with diesel fuel and the addition of antioxidants are explored also. The data indicate that without antioxidants, biodiesel will oxidize very quickly at temperatures typical of diesel engines. This oxidation results in increases in peroxide value, acid value, and viscosity. While the peroxide value generally reaches a plateau of about 350 meq/kg ester, the acid value and viscosity increase monotonically as oxidation proceeds.

  14. Asymmetric oxidation of 1,3-dithianes to 1,3-dithiane 1-oxides

    OpenAIRE

    Yoshihiko, Watanabe; Yojiro, Ono; Yoshio, Ueno; Takeshi, Toru

    1998-01-01

    Oxidation of 2-(1-hydroxy-1-methylethyl)-1,3-dithiane with the Sharpless reagent has been examined under various reaction conditions. Oxidation of 2-(1-hydroxy-1-methylethyl)-1,3-dithiane with Ti(OPri)4-diethyl L-(+)-tartrate-tert-butyl hydroperoxide (1:2:1.5) in CH2Cl2 in the presence of 4 A molecular sieves gives (1S,2S)-2-(1-hydroxy-1-methylethyl)-1,3-dithiane 1-oxide with high trans selectivity and with moderate enantioselectivity. The enantioselectivity depends upon the substituent at t...

  15. On hydrazine oxidation in nitric acid media

    International Nuclear Information System (INIS)

    Zil'berman, B.Ya.; Lelyuk, G.A.; Mashkin, A.N.; Yasnovitskaya, A.L.

    1988-01-01

    Yield of products of radiolytic ( 60 Co gamma radiation) and chemical hydrazine (HZ) oxidation in nitric acid media is studied. Under radiolyte HZ oxidation by nitric acid hydrazoic acid, ammonia and nitrogen appear to be the reaction products. HN 3 yield maximum under HZN oxidation makes up ∼ 0.35 mol per a mol of oxiduzed HZN. Under chemical oxidation HZN is oxidized by HNO 3 according to reaction catalysed by technetium HN 3 yield makes up ∼ 0.35 mol per a mol of oxidized HZN. Radiation-chemical oxidation of HN 3 proceeds up to its complete decomposition, decomposition rate is comparable with HZ oxidation rate. Under the chemical oxidation HN 3 is more stable, it is slowly decomposed after complete HZ decomposition

  16. Corrosion-electrochemical characteristics of oxide-carbide and oxide-nitride coatings formed by electrolytic plasma

    International Nuclear Information System (INIS)

    Tomashov, N.D.; Chukalovskaya, T.V.; Medova, I.L.; Duradzhi, V.N.; Plavnik, G.M.

    1990-01-01

    The composition, structure, microhardness and corrosion-electrochemical properties of oxide-carbide and oxide-nitride coatings on titanium in 5n H 2 SO 4 , 50 deg, produced by the method of chemical-heat treatment in electrolytic plasma, containing saturation components of nitrogen and carbon, were investigated. It is shown that the coatings produced have increased hardness, possess high corrosion resistance in sulfuric acid solution at increased temperature, as to their electrochemcial behaviour they are similar to titanium carbide and nitride respectively. It is shown that high corrosion resistance is ensured by electrochemical mechanism of the oxide-carbide and oxide-nitride coating protection

  17. Enhanced photoelectrochemical activity in all-oxide heterojunction devices based on correlated "metallic" oxides.

    Science.gov (United States)

    Apgar, Brent A; Lee, Sungki; Schroeder, Lauren E; Martin, Lane W

    2013-11-20

    n-n Schottky, n-n ohmic, and p-n Schottky heterojunctions based on TiO2 /correlated "metallic" oxide couples exhibit strong solar-light absorption driven by the unique electronic structure of the "metallic" oxides. Photovoltaic and photocatalytic responses are driven by hot electron injection from the "metallic" oxide into the TiO2 , enabling new modalities of operation for energy systems. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Bridged graphite oxide materials

    Science.gov (United States)

    Herrera-Alonso, Margarita (Inventor); McAllister, Michael J. (Inventor); Aksay, Ilhan A. (Inventor); Prud'homme, Robert K. (Inventor)

    2010-01-01

    Bridged graphite oxide material comprising graphite sheets bridged by at least one diamine bridging group. The bridged graphite oxide material may be incorporated in polymer composites or used in adsorption media.

  19. Corium Oxidation at Temperatures Above 2000 K

    International Nuclear Information System (INIS)

    Hagrman, Donald L.; Rempe, Joy L.

    2001-01-01

    A mechanistic model, based on a quasi-equilibrium analysis of oxidation reactions, is proposed for predicting high-temperature corium oxidation. The analysis suggests that oxide forming on the surface of corium containing uranium, zirconium, and iron is similar to the oxides formed on zirconium and uranium as long as there is a small percentage of unoxidized zirconium or uranium in the metallic phase. This is because of the higher affinity of zirconium and uranium for oxygen. Hence, oxidation rates and heat production rates are similar to (U,Zr) compounds until nearly all the uranium and zirconium in the corium oxidizes. Oxidation rates after this point are predicted to be similar to those implied by the oxide thickness present when the forming oxide ceases to be protective, and heat generation rates should be similar to those implied by iron oxidation, i.e., ∼4% of the zirconium oxidation heating rate.The maximum atomic ratio of unoxidized iron to unoxidized liquid zirconium plus uranium for the formation of a solid protective oxide below 2800 K is estimated for a temperature, T (in Kelvin), as follows:(unoxidized iron)/(unoxidized zirconium + turanium) = (1/28){5.7/exp[-(147 061 + 12.08T log(T) - 61.03T - 0.000555T 2 /1.986T)]} 1/2 .As long as this limit is not exceeded, either zirconium or uranium metal oxidation rates and heating describe the corium oxidation rate. If this limit is exceeded, diffusion of steam to the corium surface will limit the oxidation rate, and linear time-dependent growth of a nonprotective, mostly FeO, layer will occur below the protective (Zr,U) O 2 scale. When this happens, the oxidation should be at the constant rate given by the thickness of the protective layer. Heat generation should be similar to that of iron oxidation

  20. Corium Oxidation at Temperatures Above 2000 K

    Energy Technology Data Exchange (ETDEWEB)

    Hagrman, Donald Lee; Rempe, Joy Lynn

    2001-02-01

    A mechanistic model, based on a quasi-equilibrium analysis of oxidation reactions, is proposed for predicting high-temperature corium oxidation. The analysis suggests that oxide forming on the surface of corium containing uranium, zirconium, and iron is similar to the oxides formed on zirconium and uranium as long as there is a small percentage of unoxidized zirconium or uranium in the metallic phase. This is because of the higher affinity of zirconium and uranium for oxygen. Hence, oxidation rates and heat production rates are similar to (U,Zr) compounds until nearly all the uranium and zirconium in the corium oxidizes. Oxidation rates after this point are predicted to be similar to those implied by the oxide thickness present when the forming oxide ceases to be protective, and heat generation rates should be similar to those implied by iron oxidation, i.e., ~4% of the zirconium oxidation heating rate. The maximum atomic ratio of unoxidized iron to unoxidized liquid zirconium plus uranium for the formation of a solid protective oxide below 2800 K is estimated for a temperature, T (in Kelvin), as follows: (unoxidized iron)/(unoxidized zirconium + turanium) = (1/28){5.7/exp[-(147 061 + 12.08T log(T) - 61.03T - 0.000555T2/1.986T)]}1/2. As long as this limit is not exceeded, either zirconium or uranium metal oxidation rates and heating describe the corium oxidation rate. If this limit is exceeded, diffusion of steam to the corium surface will limit the oxidation rate, and linear time-dependent growth of a nonprotective, mostly FeO, layer will occur below the protective (Zr,U) O2 scale. When this happens, the oxidation should be at the constant rate given by the thickness of the protective layer. Heat generation should be similar to that of iron oxidation.

  1. The kinetics of iodide oxidation by the manganese oxide mineral birnessite

    Science.gov (United States)

    Fox, P.M.; Davis, J.A.; Luther, G. W.

    2009-01-01

    The kinetics of iodide (I-) and molecular iodine (I2) oxidation by the manganese oxide mineral birnessite (??-MnO2) was investigated over the pH range 4.5-6.25. I- oxidation to iodate (IO3-) proceeded as a two-step reaction through an I2 intermediate. The rate of the reaction varied with both pH and birnessite concentration, with faster oxidation occurring at lower pH and higher birnessite concentration. The disappearance of I- from solution was first order with respect to I- concentration, pH, and birnessite concentration, such that -d[I-]/dt = k[I-][H+][MnO2], where k, the third order rate constant, is equal to 1.08 ?? 0.06 ?? 107 M-2 h-1. The data are consistent with the formation of an inner sphere I- surface complex as the first step of the reaction, and the adsorption of I- exhibited significant pH dependence. Both I2, and to a lesser extent, IO3- sorbed to birnessite. The results indicate that iodine transport in mildly acidic groundwater systems may not be conservative. Because of the higher adsorption of the oxidized I species I2 and IO3-, as well as the biophilic nature of I2, redox transformations of iodine must be taken into account when predicting I transport in aquifers and watersheds.

  2. Thermal Oxidation of Structured Silicon Dioxide

    DEFF Research Database (Denmark)

    Christiansen, Thomas Lehrmann; Hansen, Ole; Jensen, Jørgen Arendt

    2014-01-01

    The topography of thermally oxidized, structured silicon dioxide is investigated through simulations, atomic force microscopy, and a proposed analytical model. A 357 nm thick oxide is structured by removing regions of the oxide in a masked etch with either reactive ion etching or hydrofluoric acid....... Subsequent thermal oxidation is performed in both dry and wet ambients in the temperature range 950◦C to 1100◦C growing a 205 ± 12 nm thick oxide in the etched mask windows. Lifting of the original oxide near the edge of the mask in the range 6 nm to 37 nm is seen with increased lifting for increasing...

  3. 49 CFR 172.426 - OXIDIZER label.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false OXIDIZER label. 172.426 Section 172.426... SECURITY PLANS Labeling § 172.426 OXIDIZER label. (a) Except for size and color, the OXIDIZER label must be... OXIDIZER label must be yellow. [Amdt. 172-123, 56 FR 66257, Dec. 20, 1991] ...

  4. Oxide nanoparticles in an Al-alloyed oxide dispersion strengthened steel: crystallographic structure and interface with ferrite matrix

    Science.gov (United States)

    Zhang, Zhenbo; Pantleon, Wolfgang

    2017-07-01

    Oxide nanoparticles are quintessential for ensuring the extraordinary properties of oxide dispersion strengthened (ODS) steels. In this study, the crystallographic structure of oxide nanoparticles, and their interface with the ferritic steel matrix in an Al-alloyed ODS steel, i.e. PM2000, were systematically investigated by high-resolution transmission electron microscopy. The majority of oxide nanoparticles were identified to be orthorhombic YAlO3. During hot consolidation and extrusion, they develop a coherent interface and a near cuboid-on-cube orientation relationship with the ferrite matrix in the material. After annealing at 1200 °C for 1 h, however, the orientation relationship between the oxide nanoparticles and the matrix becomes arbitrary, and their interface mostly incoherent. Annealing at 1300 °C leads to considerable coarsening of oxide nanoparticles, and a new orientation relationship of pseudo-cube-on-cube between oxide nanoparticles and ferrite matrix develops. The reason for the developing interfaces and orientation relationships between oxide nanoparticles and ferrite matrix under different conditions is discussed.

  5. Formation of iron (hydr)oxides during the abiotic oxidation of Fe(II) in the presence of arsenate.

    Science.gov (United States)

    Song, Jia; Jia, Shao-Yi; Yu, Bo; Wu, Song-Hai; Han, Xu

    2015-08-30

    Abiotic oxidation of Fe(II) is a common pathway in the formation of Fe (hydr)oxides under natural conditions, however, little is known regarding the presence of arsenate on this process. In hence, the effect of arsenate on the precipitation of Fe (hydr)oxides during the oxidation of Fe(II) is investigated. Formation of arsenic-containing Fe (hydr)oxides is constrained by pH and molar ratios of As:Fe during the oxidation Fe(II). At pH 6.0, arsenate inhibits the formation of lepidocrocite and goethite, while favors the formation of ferric arsenate with the increasing As:Fe ratio. At pH 7.0, arsenate promotes the formation of hollow-structured Fe (hydr)oxides containing arsenate, as the As:Fe ratio reaches 0.07. Arsenate effectively inhibits the formation of magnetite at pH 8.0 even at As:Fe ratio of 0.01, while favors the formation of lepidocrocite and green rust, which can be latterly degenerated and replaced by ferric arsenate with the increasing As:Fe ratio. This study indicates that arsenate and low pH value favor the slow growth of dense-structured Fe (hydr)oxides like spherical ferric arsenate. With the rapid oxidation rate of Fe(II) at high pH, ferric (hydr)oxides prefer to precipitate in the formation of loose-structured Fe (hydr)oxides like lepidocrocite and green rust. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Continuous lengths of oxide superconductors

    Science.gov (United States)

    Kroeger, Donald M.; List, III, Frederick A.

    2000-01-01

    A layered oxide superconductor prepared by depositing a superconductor precursor powder on a continuous length of a first substrate ribbon. A continuous length of a second substrate ribbon is overlaid on the first substrate ribbon. Sufficient pressure is applied to form a bound layered superconductor precursor powder between the first substrate ribbon and the second substrate ribbon. The layered superconductor precursor is then heat treated to establish the oxide superconducting phase. The layered oxide superconductor has a smooth interface between the substrate and the oxide superconductor.

  7. Tantalum high-temperature oxidation kinetics

    International Nuclear Information System (INIS)

    Grigor'ev, Yu.M.; Sarkisyan, A.A.; Merzhanov, A.G.

    1981-01-01

    Kinetics of heat release and scale growth during tantalum oxidation within 650-1300 deg C temperature range in oxygen-containing media is investigated. Kinetic equations and temperature and pressure dependences of constants are ound Applicability of the kinetic Lorie mechanism for the description of the tantalum oxidation kinetics applicably to rapid-passing processes is shown. It is stated that the process rate (reaction ability) is determined by adsorption desorption factors on the external surface of the ''protective'' oxide for the ''linear'' oxidation stage [ru

  8. Selective catalytic oxidation of ammonia

    Energy Technology Data Exchange (ETDEWEB)

    Leppaelahti, J; Koljonen, T [VTT Energy, Espoo (Finland)

    1997-12-31

    In the combustion of fossil fuels, the principal source of nitrogen oxides is nitrogen bound in the fuel structure. In gasification, a large part of fuel nitrogen forms NH{sub 3}, which may form nitrogen oxides during gas combustion. If NH{sub 3} and other nitrogen species could be removed from hot gas, the NO emission could be considerably reduced. However, relatively little attention has been paid to finding new means of removing nitrogen compounds from the hot gasification gas. The possibility of selectively oxidizing NH{sub 3} to N{sub 2} in the hot gasification has been studied at VTT Energy. The largest NH{sub 3} reductions have been achieved by catalytic oxidation on aluminium oxides. (author) (4 refs.)

  9. Selective catalytic oxidation of ammonia

    Energy Technology Data Exchange (ETDEWEB)

    Leppaelahti, J.; Koljonen, T. [VTT Energy, Espoo (Finland)

    1996-12-31

    In the combustion of fossil fuels, the principal source of nitrogen oxides is nitrogen bound in the fuel structure. In gasification, a large part of fuel nitrogen forms NH{sub 3}, which may form nitrogen oxides during gas combustion. If NH{sub 3} and other nitrogen species could be removed from hot gas, the NO emission could be considerably reduced. However, relatively little attention has been paid to finding new means of removing nitrogen compounds from the hot gasification gas. The possibility of selectively oxidizing NH{sub 3} to N{sub 2} in the hot gasification has been studied at VTT Energy. The largest NH{sub 3} reductions have been achieved by catalytic oxidation on aluminium oxides. (author) (4 refs.)

  10. Titanium Oxide/Platinum Catalysis: Charge Transfer from a Titanium Oxide Support Controls Activity and Selectivity in Methanol Oxidation on Platinum

    KAUST Repository

    Hervier, Antoine

    2011-11-24

    Platinum films of 1 nm thickness were deposited by electron beam evaporation onto 100 nm thick titanium oxide films (TiOx) with variable oxygen vacancy concentrations and fluorine (F) doping. Methanol oxidation on the platinum films produced formaldehyde, methyl formate, and carbon dioxide. F-doped samples demonstrated significantly higher activity for methanol oxidation when the TiOx was stoichiometric (TiO 2), but lower activity when it was nonstoichiometric (TiO 1.7 and TiO1.9). These results correlate with the chemical behavior of the same types of catalysts in CO oxidation. Fluorine doping of stoichiometric TiO2 also increased selectivity toward partial oxidation of methanol to formaldehyde and methyl formate, but had an opposite effect in the case of nonstoichiometric TiOx. Introduction of oxygen vacancies and fluorine doping both increased the conductivity of the TiO x film. For oxygen vacancies, this occurred by the formation of a conduction channel in the band gap, whereas in the case of fluorine doping, F acted as an n-type donor, forming a conduction channel at the bottom of the conduction band, about 0.5-1.0 eV higher in energy. The higher energy electrons in F-doped stoichiometric TiOx led to higher turnover rates and increased selectivity toward partial oxidation of methanol. This correlation between electronic structure and turnover rate and selectivity indicates that the ability of the support to transfer charges to surface species controls in part the activity and selectivity of the reaction. © 2011 American Chemical Society.

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

    Science.gov (United States)

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

    2016-01-01

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

  12. 21 CFR 73.2250 - Iron oxides.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Iron oxides. 73.2250 Section 73.2250 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2250 Iron oxides. (a) Identity. The color additives iron oxides consist of any one or any combination of synthetically prepared iron oxides, including the...

  13. Diffusion of hydrogen in iron oxides

    International Nuclear Information System (INIS)

    Bruzzoni, P.

    1993-01-01

    The diffusion of hydrogen in transitions metals oxides has been recently studied at room temperature through the permeability electrochemical technique. This work studies thin oxide layers grown in air or in presence of oxidizing atmospheres at temperatures up to 200 deg C. The substrate was pure iron with different superficial treatments. It was observed that these oxides reduce up to three magnitudes orders, the hydrogen stationary flux through membranes of usual thickness in comparison with iron membranes free of oxide. (Author)

  14. Facile synthesis of iron oxides/reduced graphene oxide composites: application for electromagnetic wave absorption at high temperature.

    Science.gov (United States)

    Zhang, Lili; Yu, Xinxin; Hu, Hongrui; Li, Yang; Wu, Mingzai; Wang, Zhongzhu; Li, Guang; Sun, Zhaoqi; Chen, Changle

    2015-03-19

    Iron oxides/reduced graphene oxide composites were synthesized by facile thermochemical reactions of graphite oxide and FeSO4 · 7H2O. By adjusting reaction temperature, α-Fe2O3/reduced graphene oxide and Fe3O4/reduced graphene oxide composites can be obtained conveniently. Graphene oxide and reduced graphene oxide sheets were demonstrated to regulate the phase transition from α-Fe2O3 to Fe3O4 via γ-Fe2O3, which was reported for the first time. The hydroxyl groups attached on the graphene oxide sheets and H2 gas generated during the annealing of graphene oxide are believed to play an important role during these phase transformations. These samples showed good electromagnetic wave absorption performance due to their electromagnetic complementary effect. These samples possess much better electromagnetic wave absorption properties than the mixture of separately prepared Fe3O4 with rGO, suggesting the crucial role of synthetic method in determining the product properties. Also, these samples perform much better than commercial absorbers. Most importantly, the great stability of these composites is highly advantageous for applications as electromagnetic wave absorption materials at high temperatures.

  15. The aqueous chemistry of oxides

    CERN Document Server

    Bunker, Bruce C

    2016-01-01

    The Aqueous Chemistry of Oxides is a comprehensive reference volume and special topics textbook that explores all of the major chemical reactions that take place between oxides and aqueous solutions. The book highlights the enormous impact that oxide-water reactions have in advanced technologies, materials science, geochemistry, and environmental science.

  16. Microstructural investigation of the oxide formed on TP 347H FG during long-term steam oxidation

    DEFF Research Database (Denmark)

    Hansson, Anette Nørgaard; Danielsen, Hilmar Kjartansson; Grumsen, Flemming Bjerg

    2010-01-01

    The long-term oxidation behaviour of TP347H FG in ultra supercritical steam conditions was assessed by exposing the steel in test superheater loops in a Danish coal-fired power plant and characterising the oxide layer with reflective light and electron microscopy. Double layered oxide scales formed...... during steam oxidation. TEM investigations reveal that the inner oxide layer consists of particles of metallic Ni/Fe and Fe-Cr spinel in the interior of the former alloy grains and a compact layer of Fe-Cr spinel and Cr2O3 along the former alloy grain boundaries. The morphology suggests that the inner...

  17. Biological Superoxide In Manganese Oxide Formation

    Science.gov (United States)

    Hansel, C.; Learman, D.; Zeiner, C.; Santelli, C. M.

    2011-12-01

    Manganese (Mn) oxides are among the strongest sorbents and oxidants within the environment, controlling the fate and transport of numerous elements and the degradation of recalcitrant carbon. Both bacteria and fungi mediate the oxidation of Mn(II) to Mn(III/IV) oxides but the genetic and biochemical mechanisms responsible remain poorly understood. Furthermore, the physiological basis for microbial Mn(II) oxidation remains an enigma. We have recently reported that a common marine bacterium (Roseobacter sp. AzwK-3b) oxidizes Mn(II) via reaction with extracellular superoxide (O2-) produced during exponential growth. Here we expand this superoxide-mediated Mn(II) oxidation pathway to fungi, introducing a surprising homology between prokaryotic and eukaryotic metal redox processes. For instance, Stibella aciculosa, a common soil Ascomycete filamentous fungus, precipitates Mn oxides at the base of asexual reproductive structures (synnemata) used to support conidia (Figure 1). This distribution is a consequence of localized production of superoxide (and it's dismutation product hydrogen peroxide, H2O2), leading to abiotic oxidation of Mn(II) by superoxide. Disruption of NADPH oxidase activity using the oxidoreductase inhibitor DPI leads to diminished cell differentiation and subsequent Mn(II) oxidation inhibition. Addition of Cu(II) (an effective superoxide scavenger) leads to a concentration dependent decrease in Mn oxide formation. We predict that due to the widespread production of extracellular superoxide within the fungal and likely bacterial kingdoms, biological superoxide may be an important contributor to the cycling of Mn, as well as other metals (e.g., Hg, Fe). Current and future explorations of the genes and proteins involved in superoxide production and Mn(II) oxidation will ideally lend insight into the physiological and biochemical basis for these processes.

  18. Oxidized limonene and oxidized linalool - Concomitant contact allergy to common fragrance terpenes

    DEFF Research Database (Denmark)

    Bråred Christensson, Johanna; Karlberg, Ann Therese; Andersen, Klaus E.

    2016-01-01

    Summary Background Limonene and linalool are common fragrance terpenes. Both oxidized R-limonene and oxidized linalool have recently been patch tested in an international setting, showing contact allergy in 5.2% and 6.9% of dermatitis patients, respectively. Objective To investigate concomitant r...

  19. Aspiperidine oxide, a piperidine N-oxide from the filamentous fungus Aspergillus indologenus

    DEFF Research Database (Denmark)

    Petersen, Lene Maj; Kildgaard, Sara; Jaspars, Marcel

    2015-01-01

    A novel secondary metabolite, aspiperidine oxide, was isolated from the filamentous fungus, Aspergillus indologenus. The structure of aspiperidine oxide was determined from extensive 1D and 2D NMR spectroscopic analysis supported by high-resolution mass spectrometry. The structure revealed a rare...

  20. Mesoporous Transition Metal Oxides for Supercapacitors

    Science.gov (United States)

    Wang, Yan; Guo, Jin; Wang, Tingfeng; Shao, Junfeng; Wang, Dong; Yang, Ying-Wei

    2015-01-01

    Recently, transition metal oxides, such as ruthenium oxide (RuO2), manganese dioxide (MnO2), nickel oxides (NiO) and cobalt oxide (Co3O4), have been widely investigated as electrode materials for pseudo-capacitors. In particular, these metal oxides with mesoporous structures have become very hot nanomaterials in the field of supercapacitors owing to their large specific surface areas and suitable pore size distributions. The high specific capacities of these mesoporous metal oxides are resulted from the effective contacts between electrode materials and electrolytes as well as fast transportation of ions and electrons in the bulk of electrode and at the interface of electrode and electrolyte. During the past decade, many achievements on mesoporous transition metal oxides have been made. In this mini-review, we select several typical nanomaterials, such as RuO2, MnO2, NiO, Co3O4 and nickel cobaltite (NiCo2O4), and briefly summarize the recent research progress of these mesoporous transition metal oxides-based electrodes in the field of supercapacitors. PMID:28347088

  1. Mesoporous Transition Metal Oxides for Supercapacitors

    Directory of Open Access Journals (Sweden)

    Yan Wang

    2015-10-01

    Full Text Available Recently, transition metal oxides, such as ruthenium oxide (RuO2, manganese dioxide (MnO2, nickel oxides (NiO and cobalt oxide (Co3O4, have been widely investigated as electrode materials for pseudo-capacitors. In particular, these metal oxides with mesoporous structures have become very hot nanomaterials in the field of supercapacitors owing to their large specific surface areas and suitable pore size distributions. The high specific capacities of these mesoporous metal oxides are resulted from the effective contacts between electrode materials and electrolytes as well as fast transportation of ions and electrons in the bulk of electrode and at the interface of electrode and electrolyte. During the past decade, many achievements on mesoporous transition metal oxides have been made. In this mini-review, we select several typical nanomaterials, such as RuO2, MnO2, NiO, Co3O4 and nickel cobaltite (NiCo2O4, and briefly summarize the recent research progress of these mesoporous transition metal oxides-based electrodes in the field of supercapacitors.

  2. Nitrous oxide-based techniques versus nitrous oxide-free techniques for general anaesthesia.

    Science.gov (United States)

    Sun, Rao; Jia, Wen Qin; Zhang, Peng; Yang, KeHu; Tian, Jin Hui; Ma, Bin; Liu, Yali; Jia, Run H; Luo, Xiao F; Kuriyama, Akira

    2015-11-06

    Nitrous oxide has been used for over 160 years for the induction and maintenance of general anaesthesia. It has been used as a sole agent but is most often employed as part of a technique using other anaesthetic gases, intravenous agents, or both. Its low tissue solubility (and therefore rapid kinetics), low cost, and low rate of cardiorespiratory complications have made nitrous oxide by far the most commonly used general anaesthetic. The accumulating evidence regarding adverse effects of nitrous oxide administration has led many anaesthetists to question its continued routine use in a variety of operating room settings. Adverse events may result from both the biological actions of nitrous oxide and the fact that to deliver an effective dose, nitrous oxide, which is a relatively weak anaesthetic agent, needs to be given in high concentrations that restrict oxygen delivery (for example, a common mixture is 30% oxygen with 70% nitrous oxide). As well as the risk of low blood oxygen levels, concerns have also been raised regarding the risk of compromising the immune system, impaired cognition, postoperative cardiovascular complications, bowel obstruction from distention, and possible respiratory compromise. To determine if nitrous oxide-based anaesthesia results in similar outcomes to nitrous oxide-free anaesthesia in adults undergoing surgery. We searched the Cochrane Central Register of Controlled Trials (CENTRAL; 2014 Issue 10); MEDLINE (1966 to 17 October 2014); EMBASE (1974 to 17 October 2014); and ISI Web of Science (1974 to 17 October 2014). We also searched the reference lists of relevant articles, conference proceedings, and ongoing trials up to 17 October 2014 on specific websites (http://clinicaltrials.gov/, http://controlled-trials.com/, and http://www.centerwatch.com). We included randomized controlled trials (RCTs) comparing general anaesthesia where nitrous oxide was part of the anaesthetic technique used for the induction or maintenance of general

  3. The oxidation and corrosion of ODS alloys

    Science.gov (United States)

    Lowell, Carl E.; Barrett, Charles A.

    1990-01-01

    The oxidation and hot corrosion of high temperature oxide dispersion strengthened (ODS) alloys are reviewed. The environmental resistance of such alloys are classified by oxide growth rate, oxide volatility, oxide spalling, and hot corrosion limitations. Also discussed are environmentally resistant coatings for ODS materials. It is concluded that ODS NiCrAl and FeCrAl alloys are highly oxidation and corrosion resistant and can probably be used uncoated.

  4. Oxidation And Hot Corrosion Of ODS Alloy

    Science.gov (United States)

    Lowell, Carl E.; Barrett, Charles A.

    1993-01-01

    Report reviews oxidation and hot corrosion of oxide-dispersion-strengthened (ODS) alloys, intended for use at high temperatures. Classifies environmental resistances of such alloys by rates of growth of oxides, volatilities of oxides, spalling of oxides, and limitations imposed by hot corrosion. Also discusses environmentally resistant coatings for ODS materials. Concludes ODS NICrAl and FeCrAl alloys highly resistant to oxidation and corrosion and can be used uncoated.

  5. The Inhibition Effect of Cell DNA Oxidative Damage and LDL Oxidation by Bovine Colostrums

    Directory of Open Access Journals (Sweden)

    Chih-Wei Chen

    2016-10-01

    Full Text Available In the present study, we investigated the effect of bovine colostrums on inhibition of DNA oxidative damage and low density lipoprotein (LDL oxidation in vitro. Results showed that whey and skimmed milk exhibited not only higher inhibitory activities of oxidative damage of deoxyribose but also an inhibitory effect on the breakdown of supercoiled DNA into open circular DNA and linear DNA. The quantities of 8-OH-2′-dG formed under whey, caseins and skimmed milk treatment were 0.24, 0.24 and 1.24 μg/mL, respectively. The quantity of malondialdehyde formed through LDL oxidation induced by copprous ion was significantly decreased as colostrums protein solutions were added, in which whey and caseins led to a more significant decrease than skimmed milk. The formation of conjugated dienes could be inhibited by treatment with colostrums protein solutions. Whey exhibited the longest lag time of conjugated dienes formation among the colostrums proteins. The lag time of the whey was 2.33 times that of the control. From the results of foregoing, the bovine colostrums protein has potential value in the inhibition of DNA oxidation damage and LDL oxidation.

  6. Study of film graphene/graphene oxide obtained by partial reduction chemical of oxide graphite

    International Nuclear Information System (INIS)

    Gascho, J.L.S.; Costa, S.F.; Hoepfner, J.C.; Pezzin, S.H.

    2014-01-01

    This study investigated the morphology of graphene/graphene oxide film obtained by partial chemical reduction of graphite oxide (OG) as well as its resistance to solvents. Films of graphene/graphene oxide are great candidates for replacement of indium oxide doped with tin (ITO) in photoelectric devices. The OG was obtained from natural graphite, by Hummer's method modified, and its reduction is made by using sodium borohydride. Infrared spectroscopy analysis of Fourier transform (FTIR), Xray diffraction (XRD) and scanning electron microscopy, high-resolution (SEM/FEG) for the characterization of graphene/graphene oxide film obtained were performed. This film proved to be resilient, not dispersing in any of the various tested solvents (such as ethanol, acetone and THF), even under tip sonication, this resistance being an important property for the applications. Furthermore, the film had a morphology similar to that obtained by other preparation methods.(author)

  7. 46 CFR 154.1725 - Ethylene oxide.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Ethylene oxide. 154.1725 Section 154.1725 Shipping COAST....1725 Ethylene oxide. (a) A vessel carrying ethylene oxide must: (1) Have cargo piping, vent piping, and... space of an ethylene oxide cargo tank for a period of 30 days under the condition of paragraph (e) of...

  8. Hydrogen Oxidation Reaction at the Ni/YSZ Anode of Solid Oxide Fuel Cells from First Principles

    Science.gov (United States)

    Cucinotta, Clotilde S.; Bernasconi, Marco; Parrinello, Michele

    2011-11-01

    By means of ab initio simulations we here provide a comprehensive scenario for hydrogen oxidation reactions at the Ni/zirconia anode of solid oxide fuel cells. The simulations have also revealed that in the presence of water chemisorbed at the oxide surface, the active region for H oxidation actually extends beyond the metal/zirconia interface unraveling the role of water partial pressure in the decrease of the polarization resistance observed experimentally.

  9. Thin film metal-oxides

    CERN Document Server

    Ramanathan, Shriram

    2009-01-01

    Presents an account of the fundamental structure-property relations in oxide thin films. This title discusses the functional properties of thin film oxides in the context of applications in the electronics and renewable energy technologies.

  10. Characterization of low-temperature microwave loss of thin aluminum oxide formed by plasma oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Chunqing, E-mail: cdeng@uwaterloo.ca; Otto, M.; Lupascu, A., E-mail: alupascu@uwaterloo.ca [Institute for Quantum Computing, Department of Physics and Astronomy, and Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada)

    2014-01-27

    We report on the characterization of microwave loss of thin aluminum oxide films at low temperatures using superconducting lumped resonators. The oxide films are fabricated using plasma oxidation of aluminum and have a thickness of 5 nm. We measure the dielectric loss versus microwave power for resonators with frequencies in the GHz range at temperatures from 54 to 303 mK. The power and temperature dependence of the loss are consistent with the tunneling two-level system theory. These results are relevant to understanding decoherence in superconducting quantum devices. The obtained oxide films are thin and robust, making them suitable for capacitors in compact microwave resonators.

  11. Serum oxidative-anti-oxidative stress balance is dysregulated in patients with hepatitis C virus-related hepatocellular carcinoma.

    Science.gov (United States)

    Nishimura, Mamoru; Takaki, Akinobu; Tamaki, Naofumi; Maruyama, Takayuki; Onishi, Hideki; Kobayashi, Sayo; Nouso, Kazuhiro; Yasunaka, Tetsuya; Koike, Kazuko; Hagihara, Hiroaki; Kuwaki, Kenji; Nakamura, Shinichiro; Ikeda, Fusao; Iwasaki, Yoshiaki; Tomofuji, Takaaki; Morita, Manabu; Yamamoto, Kazuhide

    2013-10-01

    Oxidative stress is associated with progression of chronic liver disease (CLD). This association is best established in chronic hepatitis C. However, the anti-oxidative state is not well characterized. The objective of the present study was to investigate the balance of oxidative and anti-oxidative stress in CLD patients. We recruited a study population of 208 patients, including healthy volunteers (HV; n = 15), patients with hepatitis B virus (HBV)-related CLD without or with hepatocellular carcinoma (HBV-non-HCC, n = 25, and HBV-HCC, n = 50, respectively), and patients with hepatitis C virus (HCV)-related CLD without or with HCC (HCV-non-HCC, n = 49, and HCV-HCC, n = 69, respectively). Serum levels of reactive oxygen metabolites (ROM) and anti-oxidative markers (OXY-adsorbent test; OXY) were determined, and the balance of these values was used as the oxidative index. Correlations among ROM, OXY, oxidative index and clinical characteristics were investigated. Patients with CLD exhibited elevated ROM and oxidative index compared to HV. Among patients with CLD, HCV positive status correlated with increased ROM. In CLD, HCV-HCC patients exhibited the highest ROM levels. Among HCV-related CLD patients, lower OXY correlated with HCC positive status, but was recovered by eradication of HCC. In HCV-HCC, lower OXY correlated with high PT-INR. HCV positive CLD patients displayed higher oxidative stress and HCV-HCC patients displayed lower anti-oxidative state. Anti-oxidative state depression was associated with liver reservoir-related data in HCV-HCC and could be reversed with HCC eradication. © 2012 The Japan Society of Hepatology.

  12. Antimicrobial Activity of Nitric Oxide-Releasing Ti-6Al-4V Metal Oxide

    Science.gov (United States)

    Reger, Nina A.; Meng, Wilson S.; Gawalt, Ellen S.

    2017-01-01

    Titanium and titanium alloy materials are commonly used in joint replacements, due to the high strength of the materials. Pathogenic microorganisms can easily adhere to the surface of the metal implant, leading to an increased potential for implant failure. The surface of a titanium-aluminum-vanadium (Ti-6Al-4V) metal oxide implant material was functionalized to deliver an small antibacterial molecule, nitric oxide. S-nitroso-penicillamine, a S-nitrosothiol nitric oxide donor, was covalently immobilized on the metal oxide surface using self-assembled monolayers. Infrared spectroscopy was used to confirm the attachment of the S-nitrosothiol donor to the Ti-Al-4V surface. Attachment of S-nitroso-penicillamine resulted in a nitric oxide (NO) release of 89.6 ± 4.8 nmol/cm2 under physiological conditions. This low concentration of nitric oxide reduced Escherichia coli and Staphylococcus epidermidis growth by 41.5 ± 1.2% and 25.3 ± 0.6%, respectively. Combining the S-nitrosothiol releasing Ti-6Al-4V with tetracycline, a commonly-prescribed antibiotic, increased the effectiveness of the antibiotic by 35.4 ± 1.3%, which allows for lower doses of antibiotics to be used. A synergistic effect of ampicillin with S-nitroso-penicillamine-modified Ti-6Al-4V against S. epidermidis was not observed. The functionalized Ti-6Al-4V surface was not cytotoxic to mouse fibroblasts. PMID:28635681

  13. Nanotoxicology of Metal Oxide Nanoparticles

    Directory of Open Access Journals (Sweden)

    Amedea B. Seabra

    2015-06-01

    Full Text Available This review discusses recent advances in the synthesis, characterization and toxicity of metal oxide nanoparticles obtained mainly through biogenic (green processes. The in vitro and in vivo toxicities of these oxides are discussed including a consideration of the factors important for safe use of these nanomaterials. The toxicities of different metal oxide nanoparticles are compared. The importance of biogenic synthesized metal oxide nanoparticles has been increasing in recent years; however, more studies aimed at better characterizing the potent toxicity of these nanoparticles are still necessary for nanosafely considerations and environmental perspectives. In this context, this review aims to inspire new research in the design of green approaches to obtain metal oxide nanoparticles for biomedical and technological applications and to highlight the critical need to fully investigate the nanotoxicity of these particles.

  14. BRCA1 and Oxidative Stress

    Energy Technology Data Exchange (ETDEWEB)

    Yi, Yong Weon; Kang, Hyo Jin [Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC 20057 (United States); Bae, Insoo, E-mail: ib42@georgetown.edu [Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC 20057 (United States); Department of Radiation Medicine, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC 20057 (United States)

    2014-04-03

    The breast cancer susceptibility gene 1 (BRCA1) has been well established as a tumor suppressor and functions primarily by maintaining genome integrity. Genome stability is compromised when cells are exposed to oxidative stress. Increasing evidence suggests that BRCA1 regulates oxidative stress and this may be another mechanism in preventing carcinogenesis in normal cells. Oxidative stress caused by reactive oxygen species (ROS) is implicated in carcinogenesis and is used strategically to treat human cancer. Thus, it is essential to understand the function of BRCA1 in oxidative stress regulation. In this review, we briefly summarize BRCA1’s many binding partners and mechanisms, and discuss data supporting the function of BRCA1 in oxidative stress regulation. Finally, we consider its significance in prevention and/or treatment of BRCA1-related cancers.

  15. Exploring oxidative modifications of tyrosine

    DEFF Research Database (Denmark)

    Houée-Lévin, C; Bobrowski, K; Horakova, L

    2015-01-01

    residues are oxidised in vivo with impact on cellular homeostasis and redox signalling pathways. A notable example is tyrosine, which can undergo a number of oxidative post-translational modifications to form 3-hydroxy-tyrosine, tyrosine crosslinks, 3-nitrotyrosine and halogenated tyrosine, with different...... effects on cellular functions. Tyrosine oxidation has been studied extensively in vitro, and this has generated detailed information about the molecular mechanisms that may occur in vivo. An important aspect of studying tyrosine oxidation both in vitro and in biological systems is the ability to monitor...... residues modified and the nature of the modification. These approaches have helped understanding of the consequences of tyrosine oxidation in biological systems, especially its effects on cell signalling and cell dysfunction, linking to roles in disease. There is mounting evidence that tyrosine oxidation...

  16. Composite catalyst for carbon monoxide and hydrocarbon oxidation

    Science.gov (United States)

    Liu, Wei; Flytzani-Stephanopoulos, Maria

    1996-01-01

    A method and composition for the complete oxidation of carbon monoxide and/or hydrocarbon compounds. The method involves reacting the carbon monoxide and/or hydrocarbons with an oxidizing agent in the presence of a metal oxide composite catalyst. The catalyst is prepared by combining fluorite-type oxygen ion conductors with active transition metals. The fluorite oxide, selected from the group consisting of cerium oxide, zirconium oxide, thorium oxide, hafnium oxide, and uranium oxide, and may be doped by alkaline earth and rare earth oxides. The transition metals, selected from the group consisting of molybdnum, copper, cobalt, maganese, nickel, and silver, are used as additives. The atomic ratio of transition metal to fluorite oxide is less than one.

  17. Gas phase deposition of oxide and metal-oxide coatings on fuel particles

    International Nuclear Information System (INIS)

    Patokin, A.P.; Khrebtov, V.L.; Shirokov, B.M.

    2008-01-01

    Production processes and properties of oxide (Al 2 O 3 , ZrO 2 ) and metal-oxide (Mo-Al 2 O 3 , Mo-ZrO 2 , W-Al 2 O 3 , W-ZrO 2 ) coatings on molybdenum substrates and uranium dioxide fuel particles were investigated. It is shown that the main factors that have an effect on the deposition rate, density, microstructure and other properties of coatings are the deposition temperature, the ratio of H 2 and CO 2 flow rates, the total reactor pressure and the ratio of partial pressures of corresponding metal chlorides during formation of metal-oxide coatings

  18. Oxidative and Anti-Oxidative Stress Markers in Chronic Glaucoma: A Systematic Review and Meta-Analysis

    Science.gov (United States)

    Benoist d’Azy, Cédric; Pereira, Bruno; Chiambaretta, Frédéric

    2016-01-01

    Chronic glaucoma is a multifactorial disease among which oxidative stress may play a major pathophysiological role. We conducted a systematic review and meta-analysis to evaluate the levels of oxidative and antioxidative stress markers in chronic glaucoma compared with a control group. The PubMed, Cochrane Library, Embase and Science Direct databases were searched for studies reporting oxidative and antioxidative stress markers in chronic glaucoma and in healthy controls using the following keywords: “oxidative stress” or “oxidant stress” or “nitrative stress” or “oxidative damage” or “nitrative damage” or “antioxidative stress” or “antioxidant stress” or “antinitrative stress” and “glaucoma”. We stratified our meta-analysis on the type of biomarkers, the type of glaucoma, and the origin of the sample (serum or aqueous humor). We included 22 case-control studies with a total of 2913 patients: 1614 with glaucoma and 1319 healthy controls. We included 12 studies in the meta-analysis on oxidative stress markers and 19 on antioxidative stress markers. We demonstrated an overall increase in oxidative stress markers in glaucoma (effect size = 1.64; 95%CI 1.20–2.09), ranging from an effect size of 1.29 in serum (95%CI 0.84–1.74) to 2.62 in aqueous humor (95%CI 1.60–3.65). Despite a decrease in antioxidative stress marker in serum (effect size = –0.41; 95%CI –0.72 to –0.11), some increased in aqueous humor (superoxide dismutase, effect size = 3.53; 95%CI 1.20–5.85 and glutathione peroxidase, effect size = 6.60; 95%CI 3.88–9.31). The differences in the serum levels of oxidative stress markers between glaucoma patients and controls were significantly higher in primary open angle glaucoma vs primary angle closed glaucoma (effect size = 12.7; 95%CI 8.78–16.6, P stress increased in glaucoma, both in serum and aqueous humor. Malonyldialdehyde seemed the best biomarkers of oxidative stress in serum. The increase of some

  19. The effects of iron(II) on the kinetics of arsenic oxidation and sorption on manganese oxides.

    Science.gov (United States)

    Wu, Yun; Li, Wei; Sparks, Donald L

    2015-11-01

    In this study, As(III) oxidation kinetics by a poorly-crystalline phyllomanganate (δ-MnO2) in the presence and absence of dissolved Fe(II) was investigated using stirred-flow and batch experiments. Chemically synthetic δ-MnO2 was reacted with four influent solutions, containing the same As(III) concentration but different Fe(II) concentrations, at pH 6. The results show an initial rapid As(III) oxidation by δ-MnO2, which is followed by an appreciably slow reaction after 8h. In the presence of Fe(II), As(III) oxidation is inhibited due to the competitive oxidation of Fe(II) as well as the formation of Fe(III)-(hydr)oxides on the δ-MnO2 surface. However, the sorption of As(III), As(V) and Mn(II) are increased, for the newly formed Fe(III)-(hydr)oxides provide additional sorption sites. This study suggests that the competitive oxidation of Fe(II) and consequently the precipitation of Fe(III) compounds on the δ-MnO2 surface play an important role in As(III) oxidation and As sequestration. Understanding these processes would be helpful in developing in situ strategies for remediation of As-contaminated waters and soils. Copyright © 2015 Elsevier Inc. All rights reserved.

  20. Nivalenol induces oxidative stress and increases deoxynivalenol pro-oxidant effect in intestinal epithelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Del Regno, Marisanta; Adesso, Simona; Popolo, Ada [Department of Pharmacy, School of Pharmacy, University of Salerno, Via Giovanni Paolo II, 132–84084 Fisciano, Salerno (Italy); Quaroni, Andrea [Department of Biomedical Sciences, Cornell University, Veterinary Research Tower, Cornell University, Ithaca, NY 14853–6401 (United States); Autore, Giuseppina [Department of Pharmacy, School of Pharmacy, University of Salerno, Via Giovanni Paolo II, 132–84084 Fisciano, Salerno (Italy); Severino, Lorella [Department of Pathology and Animal Health, Division of Toxicology, School of Veterinary Medicine, University of Naples “Federico II”, Via Delpino 1, 80137 Naples (Italy); Marzocco, Stefania, E-mail: smarzocco@unisa.it [Department of Pharmacy, School of Pharmacy, University of Salerno, Via Giovanni Paolo II, 132–84084 Fisciano, Salerno (Italy)

    2015-06-01

    Mycotoxins are secondary fungal metabolites often found as contaminants in almost all agricultural commodities worldwide, and the consumption of food or feed contaminated by mycotoxins represents a major risk for human and animal health. Reactive oxygen species are normal products of cellular metabolism. However, disproportionate generation of reactive oxygen species poses a serious problem to bodily homeostasis and causes oxidative tissue damage. In this study we analyzed the effect of two trichothecenes mycotoxins: nivalenol and deoxynivalenol, alone and in combination, on oxidative stress in the non-tumorigenic intestinal epithelial cell line IEC-6. Our results indicate the pro-oxidant nivalenol effect in IEC-6, the stronger pro-oxidant effect of nivalenol when compared to deoxynivalenol and, interestingly, that nivalenol increases deoxynivalenol pro-oxidative effects. Mechanistic studies indicate that the observed effects were mediated by NADPH oxidase, calcium homeostasis alteration, NF-kB and Nrf2 pathways activation and by iNOS and nitrotyrosine formation. The toxicological interaction by nivalenol and deoxynivalenol reported in this study in IEC-6, points out the importance of the toxic effect of these mycotoxins, mostly in combination, further highlighting the risk assessment process of these toxins that are of growing concern. - Highlights: • Nivalenol induces oxidative stress in intestinal epithelial cells (IECs). • Nivalenol increases deoxynivalenol pro-oxidant effects in IECs. • Nivalenol and deoxynivalenol trigger antioxidant response IECs. • These results indicate the importance of mycotoxins co-contamination.

  1. Increased electrochemical properties of ruthenium oxide and graphene/ruthenium oxide hybrid dispersed by polyvinylpyrrolidone

    International Nuclear Information System (INIS)

    Chen, Yao; Zhang, Xiong; Zhang, Dacheng; Ma, Yanwei

    2012-01-01

    Highlights: ► A good dispersion of RuO 2 and graphene/RuO 2 is obtained by polyvinylpyrrolidone. ► PVP as a dispersant also can prevent the formation of metal Ru in graphene/RuO 2 . ► The max capacitances of the hybrid and RuO 2 reach 435 and 597 F g −1 at 0.2 A g −1 . ► The hybrid shows the best rate capability of 39% at 50 A g −1 . - Abstract: Ruthenium oxide has been prepared by a sol–gel method. Polyvinylpyrrolidone (PVP) as an excellent polymeric dispersant is adopted to prevent aggregation of ruthenium oxide. In order to enhance the rate capability of ruthenium oxide, graphene with residual oxygen functional groups as a 2D support has been merged into ruthenium oxide. These oxygen functional groups not only favor to form stable few layers of graphene colloids, but also offer the sites to anchor ruthenium oxide nanoparticles. X-ray diffraction infers that PVP can also hinder the partial formation of Ru by blocking the direct contact between the Ru 3+ and the graphene in the sol–gel synthesis of the hybrids. The ruthenium oxide and the graphene/ruthenium oxide hybrids dispersed by PVP have superior electrochemical properties due to good dispersing and protecting ability of PVP. Especially, the hybrids using PVP exhibit the best rate capability, indicating that the composites possess an advanced structure of combining sheets and particles in nano-scale.

  2. A potential biomarker for fatigue: Oxidative stress and anti-oxidative activity.

    Science.gov (United States)

    Fukuda, Sanae; Nojima, Junzo; Motoki, Yukari; Yamaguti, Kouzi; Nakatomi, Yasuhito; Okawa, Naoko; Fujiwara, Kazumi; Watanabe, Yasuyoshi; Kuratsune, Hirohiko

    2016-07-01

    We sought to determine whether oxidative stress and anti-oxidative activity could act as biomarkers that discriminate patients with chronic fatigue syndrome (CFS) from healthy volunteers at acute and sub-acute fatigue and resting conditions. We calculated the oxidative stress index (OSI) from reactive oxygen metabolites-derived compounds (d-ROMs) and the biological antioxidant potential (BAP). We determined changes in d-ROMs, BAP, and OSI in acute and sub-acute fatigue in two healthy groups, and compared their values at rest between patients with CFS (diagnosed by Fukuda 1994 criteria) and another group of healthy controls. Following acute fatigue in healthy controls, d-ROMs and OSI increased, and BAP decreased. Although d-ROMs and OSI were significantly higher after sub-acute fatigue, BAP did not decrease. Resting condition yielded higher d-ROMs, higher OSI, and lower BAP in patients with CFS than in healthy volunteers, but lower d-ROMs and OSI when compared with sub-acute controls. BAP values did not significantly differ between patients with CFS and controls in the sub-acute condition. However, values were significantly higher than in the resting condition for controls. Thus, measured of oxidative stress (d-ROMS) and anti-oxidative activity (BAP) might be useful for discriminating acute, sub-acute, and resting fatigue in healthy people from patients with CFS, or for evaluating fatigue levels in healthy people. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Molybdenum Oxides - From Fundamentals to Functionality.

    Science.gov (United States)

    de Castro, Isabela Alves; Datta, Robi Shankar; Ou, Jian Zhen; Castellanos-Gomez, Andres; Sriram, Sharath; Daeneke, Torben; Kalantar-Zadeh, Kourosh

    2017-10-01

    The properties and applications of molybdenum oxides are reviewed in depth. Molybdenum is found in various oxide stoichiometries, which have been employed for different high-value research and commercial applications. The great chemical and physical characteristics of molybdenum oxides make them versatile and highly tunable for incorporation in optical, electronic, catalytic, bio, and energy systems. Variations in the oxidation states allow manipulation of the crystal structure, morphology, oxygen vacancies, and dopants, to control and engineer electronic states. Despite this overwhelming functionality and potential, a definitive resource on molybdenum oxide is still unavailable. The aim here is to provide such a resource, while presenting an insightful outlook into future prospective applications for molybdenum oxides. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Primary atmospheric oxidation mechanism for toluene.

    Science.gov (United States)

    Baltaretu, Cristian O; Lichtman, Eben I; Hadler, Amelia B; Elrod, Matthew J

    2009-01-08

    The products of the primary OH-initiated oxidation of toluene were investigated using the turbulent flow chemical ionization mass spectrometry technique at temperatures ranging from 228 to 298 K. A major dienedial-producing pathway was detected for the first time for toluene oxidation, and glyoxal and methylglyoxal were found to be minor primary oxidation products. The results suggest that secondary oxidation processes involving dienedial and epoxide primary products are likely responsible for previous observations of glyoxal and methylglyoxal products from toluene oxidation. Because the dienedial-producing pathway is a null cycle for tropospheric ozone production and glyoxal and methylglyoxal are important secondary organic aerosol precursors, these new findings have important implications for the modeling of toluene oxidation in the atmosphere.

  5. Oxidation behaviour of metallic glass foams

    Energy Technology Data Exchange (ETDEWEB)

    Barnard, B.R. [Department of Materials Science and Engineering, 434 Dougherty Hall, University of Tennessee, Knoxville, TN 37996-2200 (United States)], E-mail: bbarnard@utk.edu; Liaw, P.K. [Department of Materials Science and Engineering, 434 Dougherty Hall, University of Tennessee, Knoxville, TN 37996-2200 (United States); Demetriou, M.D.; Johnson, W.L. [Department of Materials Science, Keck Laboratory, California Institute of Technology, Pasadena, CA 91125 (United States)

    2008-08-15

    In this study, the effects of porosity on the oxidation behaviour of bulk-metallic glasses were investigated. Porous Pd- and Fe-based bulk-metallic glass (BMG) foams and Metglas ribbons were studied. Oxidizing experiments were conducted at 70 deg. C, and around 80 deg. C below glass-transition temperatures, (T{sub g}s). Scanning-electron microscopy/energy-dispersive spectroscopy (SEM/EDS) studies revealed little evidence of oxidation at 70 deg. C. Specimens exhibited greater oxidation at T{sub g} - 80 deg. C. Oxides were copper-based for Pd-based foams, Fe-, Cr-, and Mo-based for Fe-based foams, and Co-based with borosilicates likely for the Metglas. Pd-based foams demonstrated the best oxidation resistance, followed by Metglas ribbons, followed by Fe-based foams.

  6. Ni–Ta–O mixed oxide catalysts for the low temperature oxidative dehydrogenation of ethane to ethylene

    KAUST Repository

    Zhu, Haibo; Rosenfeld, Devon C.; Anjum, Dalaver H.; Sangaru, Shiv; Saih, Youssef; Ould-Chikh, Samy; Basset, Jean-Marie

    2015-01-01

    The "wet" sol-gel and "dry" solid-state methods were used to prepare Ni-Ta-O mixed oxide catalysts. The resulting Ni-Ta oxides exhibit high activity and selectivity for the low temperature oxidative dehydrogenation of ethane to ethylene. The Ta

  7. Response time in economic games reflects different types of decision conflict for prosocial and proself individuals.

    Science.gov (United States)

    Yamagishi, Toshio; Matsumoto, Yoshie; Kiyonari, Toko; Takagishi, Haruto; Li, Yang; Kanai, Ryota; Sakagami, Masamichi

    2017-06-13

    Behavioral and neuroscientific studies explore two pathways through which internalized social norms promote prosocial behavior. One pathway involves internal control of impulsive selfishness, and the other involves emotion-based prosocial preferences that are translated into behavior when they evade cognitive control for pursuing self-interest. We measured 443 participants' overall prosocial behavior in four economic games. Participants' predispositions [social value orientation (SVO)] were more strongly reflected in their overall game behavior when they made decisions quickly than when they spent a longer time. Prosocially (or selfishly) predisposed participants behaved less prosocially (or less selfishly) when they spent more time in decision making, such that their SVO prosociality yielded limited effects in actual behavior in their slow decisions. The increase (or decrease) in slower decision makers was prominent among consistent prosocials (or proselfs) whose strong preference for prosocial (or proself) goals would make it less likely to experience conflict between prosocial and proself goals. The strong effect of RT on behavior in consistent prosocials (or proselfs) suggests that conflict between prosocial and selfish goals alone is not responsible for slow decisions. Specifically, we found that contemplation of the risk of being exploited by others (social risk aversion) was partly responsible for making consistent prosocials (but not consistent proselfs) spend longer time in decision making and behave less prosocially. Conflict between means rather than between goals (immediate versus strategic pursuit of self-interest) was suggested to be responsible for the time-related increase in consistent proselfs' prosocial behavior. The findings of this study are generally in favor of the intuitive cooperation model of prosocial behavior.

  8. Control of bovine hepatic fatty acid oxidation

    International Nuclear Information System (INIS)

    Jesse, B.W.; Emery, R.S.; Thomas, J.W.

    1986-01-01

    Fatty acid oxidation by bovine liver slices and mitochondria was examined to determine potential regulatory sites of fatty acid oxidation. Conversion of 1-[ 14 C]palmitate to 14 CO 2 and total [ 14 C]acid-soluble metabolites was used to measure fatty acid oxidation. Oxidation of palmitate (1 mM) was linear in both liver slice weight and incubation time. Carnitine stimulated palmitate oxidation; 2 mM dl-carnitine produced maximal stimulation of palmitate oxidation to both CO 2 and acid-soluble metabolites. Propionate (10 mM) inhibited palmitate oxidation by bovine liver slices. Propionate (.5 to 10 mM) had no effect on palmitate oxidation by mitochondria, but malonyl Coenzyme A, the first committed intermediate of fatty acid synthesis, inhibited mitochondrial palmitate oxidation (inhibition constant = .3 μM). Liver mitochonndrial carnitine palmitoyltransferase exhibited Michaelis constants for palmitoyl Coenzyme A and l-carnitine of 11.5 μM and .59 mM, respectively. Long-chain fatty acid oxidation in bovine liver is regulated by mechanisms similar to those in rats but adapted to the unique digestive physiology of the bovine

  9. Electrosynthesis of Biomimetic Manganese-Calcium Oxides for Water Oxidation Catalysis--Atomic Structure and Functionality.

    Science.gov (United States)

    González-Flores, Diego; Zaharieva, Ivelina; Heidkamp, Jonathan; Chernev, Petko; Martínez-Moreno, Elías; Pasquini, Chiara; Mohammadi, Mohammad Reza; Klingan, Katharina; Gernet, Ulrich; Fischer, Anna; Dau, Holger

    2016-02-19

    Water-oxidizing calcium-manganese oxides, which mimic the inorganic core of the biological catalyst, were synthesized and structurally characterized by X-ray absorption spectroscopy at the manganese and calcium K edges. The amorphous, birnesite-type oxides are obtained through a simple protocol that involves electrodeposition followed by active-site creation through annealing at moderate temperatures. Calcium ions are inessential, but tune the electrocatalytic properties. For increasing calcium/manganese molar ratios, both Tafel slopes and exchange current densities decrease gradually, resulting in optimal catalytic performance at calcium/manganese molar ratios of close to 10 %. Tracking UV/Vis absorption changes during electrochemical operation suggests that inactive oxides reach their highest, all-Mn(IV) oxidation state at comparably low electrode potentials. The ability to undergo redox transitions and the presence of a minor fraction of Mn(III) ions at catalytic potentials is identified as a prerequisite for catalytic activity. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Modeling of thermal expansion coefficient of perovskite oxide for solid oxide fuel cell cathode

    Science.gov (United States)

    Heydari, F.; Maghsoudipour, A.; Alizadeh, M.; Khakpour, Z.; Javaheri, M.

    2015-09-01

    Artificial intelligence models have the capacity to eliminate the need for expensive experimental investigation in various areas of manufacturing processes, including the material science. This study investigates the applicability of adaptive neuro-fuzzy inference system (ANFIS) approach for modeling the performance parameters of thermal expansion coefficient (TEC) of perovskite oxide for solid oxide fuel cell cathode. Oxides (Ln = La, Nd, Sm and M = Fe, Ni, Mn) have been prepared and characterized to study the influence of the different cations on TEC. Experimental results have shown TEC decreases favorably with substitution of Nd3+ and Mn3+ ions in the lattice. Structural parameters of compounds have been determined by X-ray diffraction, and field emission scanning electron microscopy has been used for the morphological study. Comparison results indicated that the ANFIS technique could be employed successfully in modeling thermal expansion coefficient of perovskite oxide for solid oxide fuel cell cathode, and considerable savings in terms of cost and time could be obtained by using ANFIS technique.

  11. Markers of protein oxidation

    DEFF Research Database (Denmark)

    Headlam, Henrietta A; Davies, Michael Jonathan

    2004-01-01

    Exposure of proteins to radicals in the presence of O2 gives both side-chain oxidation and backbone fragmentation. These processes can be interrelated, with initial side-chain oxidation giving rise to backbone damage via transfer reactions. We have shown previously that alkoxyl radicals formed...... of this process depends on the extent of oxidation at C-3 compared with other sites. HO*, generated by gamma radiolysis, gave the highest total carbonyl yield, with protein-bound carbonyls predominating over released. In contrast, metal ion/H2O2 systems, gave more released than bound carbonyls, with this ratio...... modulated by EDTA. This is ascribed to metal ion-protein interactions affecting the sites of initial oxidation. Hypochlorous acid gave low concentrations of released carbonyls, but high yields of protein-bound material. The peroxyl radical generator 2,2'-azobis(2-amidinopropane) hydrochloride...

  12. Chaperones, but not oxidized proteins, are ubiquitinated after oxidative stress

    DEFF Research Database (Denmark)

    Kästle, Marc; Reeg, Sandra; Rogowska-Wrzesinska, Adelina

    2012-01-01

    of these proteins by MALDI tandem mass spectrometry (MALDI MS/MS). As a result we obtained 24 different proteins which can be categorized into the following groups: chaperones, energy metabolism, cytoskeleton/intermediate filaments, and protein translation/ribosome biogenesis. The special set of identified......, ubiquitinated proteins confirm the thesis that ubiquitination upon oxidative stress is no random process to degrade the mass of oxidized proteins, but concerns a special group of functional proteins....

  13. Limits to the adherence of oxide scales

    International Nuclear Information System (INIS)

    Robertson, J.; Manning, M.I.

    1989-10-01

    Fracture mechanics is used to identify criteria under which uniform oxide scales may be expected to fail due to rapidly applied strains. The most common failure mode occurs when the strain, ε, builds up in the scale until the strain energy density per unit area exceeds the fracture surface energy, γ, of the oxide. This produces spalling when ε > (2γ/hE) 1/2 , where h is the scale thickness and E is the oxide Youngs modulus. In thin scales, as the external strain is applied to the oxide via the metal substrate, it is clear that no further strain can be applied to the oxide if the substrate has itself been strained beyond yield. This gives rise to extended oxide adherence in which the oxide cracks and forms a series of islands but remains attached to the deformed metal. When the oxide thickness is less than its comminution limit, the flaw size necessary for brittle fracture exceeds the oxide thickness and the oxide yields in a ductile manner without cracking. The results are presented as maps of failure strain versus oxide thickness for various oxide systems such as Fe 3 O 4 , Cr 2 O 3 , Al 2 O 3 , SiO 2 and NiO. The observed cases of spalling are found to lie within the predicted regions. (author)

  14. Oxidative costs of reproduction: Oxidative stress in mice fed standard and low antioxidant diets.

    Science.gov (United States)

    Vaanholt, L M; Milne, A; Zheng, Y; Hambly, C; Mitchell, S E; Valencak, T G; Allison, D B; Speakman, J R

    2016-02-01

    Lactation is one of the most energetically expensive behaviours, and trade-offs may exist between the energy devoted to it and somatic maintenance, including protection against oxidative damage. However, conflicting data exist for the effects of reproduction on oxidative stress. In the wild, a positive relationship is often observed, but in laboratory studies oxidative damage is often lower in lactating than in non-breeding animals. We hypothesised that this discrepancy may exist because during lactation food intake increases many-fold resulting in a large increase in the intake of dietary antioxidants which are typically high in laboratory rodent chow where they are added as a preservative. We supplied lactating and non-breeding control mice with either a standard or low antioxidant diet and studied how this affected the activity of endogenous antioxidants (catalase, superoxide dismutase; SOD, and glutathione peroxidise; GPx) and oxidative damage to proteins (protein carbonyls, PC) in liver and brain tissue. The low antioxidant diet did not significantly affect activities of antioxidant enzymes in brain or liver, and generally did not result in increased protein damage, except in livers of control mice on low antioxidant diet. Catalase activity, but not GPx or SOD, was decreased in both control and lactating mice on the low antioxidant diet. Lactating mice had significantly reduced oxidative damage to both liver and brain compared to control mice, independent of the diet they were given. In conclusion, antioxidant content of the diet did not affect oxidative stress in control or reproductive mice, and cannot explain the previously observed reduction in oxidative stress in lactating mammals studied in the laboratory. The reduced oxidative stress in the livers of lactating mice even under low antioxidant diet treatment was consistent with the 'shielding' hypothesis. Copyright © 2015 Elsevier Inc. All rights reserved.

  15. Effects of Lytic Polysaccharide Monooxygenase Oxidation on Cellulose Structure and Binding of Oxidized Cellulose Oligomers to Cellulases

    Energy Technology Data Exchange (ETDEWEB)

    Vermaas, Josh V.; Crowley, Michael F.; Beckham, Gregg T.; Payne, Christina M.

    2015-05-21

    In nature, polysaccharide glycosidic bonds are cleaved by hydrolytic enzymes for a vast array of biological functions. Recently, a new class of enzymes that utilize an oxidative mechanism to cleave glycosidic linkages was discovered; these enzymes are called lytic polysaccharide monooxygenases (LPMO). These oxidative enzymes are synergistic with cocktails of hydrolytic enzymes and are thought to act primarily on crystalline regions, in turn providing new sites of productive attachment and detachment for processive hydrolytic enzymes. In the case of cellulose, the homopolymer of ..beta..-1,4-d-glucose, enzymatic oxidation occurs at either the reducing end or the nonreducing end of glucose, depending on enzymatic specificity, and results in the generation of oxidized chemical substituents at polymer chain ends. LPMO oxidation of cellulose is thought to produce either a lactone at the reducing end of glucose that can spontaneously or enzymatically convert to aldonic acid or 4-keto-aldose at the nonreducing end that may further oxidize to a geminal diol. Here, we use molecular simulation to examine the effect of oxidation on the structure of crystalline cellulose. The simulations highlight variations in behaviors depending on the chemical identity of the oxidized species and its location within the cellulose fibril, as different oxidized species introduce steric effects that disrupt local crystallinity and in some cases reduce the work needed for polymer decrystallization. Reducing-end oxidations are easiest to decrystallize when located at the end of the fibril, whereas nonreducing end oxidations readily decrystallize from internal cleavage sites despite their lower solvent accessibility. The differential in decrystallization free energy suggests a molecular mechanism consistent with experimentally observed LPMO/cellobiohydrolase synergy. Additionally, the soluble oxidized cellobiose products released by hydrolytic cellulases may bind to the active sites of cellulases

  16. Nitrile-assisted oxidation over oxidative-annulation: Pd-catalyzed α,β-dehydrogenation of α-cinnamyl β-keto nitriles.

    Science.gov (United States)

    Nallagonda, Rajender; Reddy, Reddy Rajasekhar; Ghorai, Prasanta

    2017-09-13

    A palladium-catalyzed oxidation reaction is disclosed where the nitrile functionality on the substrate simply changes the course of the reaction. Our previous finding showed that using the Pd(ii)-catalyst in the presence of benzoquinone as an oxidant, 2-cinnamyl-1,3-dicarbonyls provides functionalized furans via oxidative cyclization. When a nitrile group is replaced with one of the carbonyl functionalities of the same substrate, the oxidative cyclization was completely suppressed; instead, the oxidation at the α,β-position occurred to provide α,β,γ,δ-diene containing β-keto nitriles.

  17. Internal fuel pin oxidizer

    International Nuclear Information System (INIS)

    Andrews, M.G.

    1978-01-01

    A nuclear fuel pin has positioned within it material which will decompose to release an oxidizing agent which will react with the cladding of the pin and form a protective oxide film on the internal surface of the cladding

  18. Fungal oxidative dissolution of the Mn(II)-bearing mineral rhodochrosite and the role of metabolites in manganese oxide formation.

    Science.gov (United States)

    Tang, Yuanzhi; Zeiner, Carolyn A; Santelli, Cara M; Hansel, Colleen M

    2013-04-01

    Microbially mediated oxidation of Mn(II) to Mn(III/IV) oxides influences the cycling of metals and remineralization of carbon. Despite the prevalence of Mn(II)-bearing minerals in nature, little is known regarding the ability of microbes to oxidize mineral-hosted Mn(II). Here, we explored oxidation of the Mn(II)-bearing mineral rhodochrosite (MnCO3 ) and characteristics of ensuing Mn oxides by six Mn(II)-oxidizing Ascomycete fungi. All fungal species substantially enhanced rhodochrosite dissolution and surface modification. Mineral-hosted Mn(II) was oxidized resulting in formation of Mn(III/IV) oxides that were all similar to δ-MnO2 but varied in morphology and distribution in relation to cellular structures and the MnCO3 surface. For four fungi, Mn(II) oxidation occurred along hyphae, likely mediated by cell wall-associated proteins. For two species, Mn(II) oxidation occurred via reaction with fungal-derived superoxide produced at hyphal tips. This pathway ultimately resulted in structurally unique Mn oxide clusters formed at substantial distances from any cellular structure. Taken together, findings for these two fungi strongly point to a role for fungal-derived organic molecules in Mn(III) complexation and Mn oxide templation. Overall, this study illustrates the importance of fungi in rhodochrosite dissolution, extends the relevance of biogenic superoxide-based Mn(II) oxidation and highlights the potential role of mycogenic exudates in directing mineral precipitation. © 2012 Society for Applied Microbiology and Blackwell Publishing Ltd.

  19. Electrode Reaction Pathway in Oxide Anode for Solid Oxide Fuel Cells

    Science.gov (United States)

    Li, Wenyuan

    Oxide anodes for solid oxide fuel cells (SOFC) with the advantage of fuel flexibility, resistance to coarsening, small chemical expansion and etc. have been attracting increasing interest. Good performance has been reported with a few of perovskite structure anodes, such as (LaSr)(CrMn)O3. However, more improvements need to be made before meeting the application requirement. Understanding the oxidation mechanism is crucial for a directed optimization, but it is still on the early stage of investigation. In this study, reaction mechanism of oxide anodes is investigated on doped YCrO 3 with H2 fuel, in terms of the origin of electrochemical activity, rate-determining steps (RDS), extension of reactive zone, and the impact from overpotential under service condition to those properties. H2 oxidation on the YCs anodes is found to be limited by charge transfer and H surface diffusion. A model is presented to describe the elementary steps in H2 oxidation. From the reaction order results, it is suggested that any models without taking H into the charge transfer step are invalid. The nature of B site element determines the H2 oxidation kinetics primarily. Ni displays better adsorption ability than Co. However, H adsorption ability of such oxide anode is inferior to that of Ni metal anode. In addition, the charge transfer step is directly associated with the activity of electrons in the anode; therefore it can be significantly promoted by enhancement of the electron activity. It is found that A site Ca doping improves the polarization resistance about 10 times, by increasing the activity of electrons to promote the charge transfer process. For the active area in the oxide anode, besides the traditional three-phase boundary (3PB), the internal anode surface as two-phase boundary (2PB) is proven to be capable of catalytically oxidizing the H2 fuel also when the bulk lattice is activated depending on the B site elements. The contribution from each part is estimated by switching

  20. Protein oxidation in muscle foods: A review

    DEFF Research Database (Denmark)

    Lund, Marianne; Heinonen, Marina; Baron, Caroline P.

    2011-01-01

    insight into the reactions involved in the oxidative modifications undergone by muscle proteins. Moreover, a variety of products derived from oxidized muscle proteins, including cross-links and carbonyls, have been identified. The impact of oxidation on protein functionality and on specific meat quality...... and consequences of Pox in muscle foods. The efficiency of different anti-oxidant strategies against the oxidation of muscle proteins is also reported.......Protein oxidation in living tissues is known to play an essential role in the pathogenesis of relevant degenerative diseases, whereas the occurrence and impact of protein oxidation (Pox) in food systems have been ignored for decades. Currently, the increasing interest among food scientists...

  1. Iron oxide surfaces

    Science.gov (United States)

    Parkinson, Gareth S.

    2016-03-01

    The current status of knowledge regarding the surfaces of the iron oxides, magnetite (Fe3O4), maghemite (γ-Fe2O3), haematite (α-Fe2O3), and wüstite (Fe1-xO) is reviewed. The paper starts with a summary of applications where iron oxide surfaces play a major role, including corrosion, catalysis, spintronics, magnetic nanoparticles (MNPs), biomedicine, photoelectrochemical water splitting and groundwater remediation. The bulk structure and properties are then briefly presented; each compound is based on a close-packed anion lattice, with a different distribution and oxidation state of the Fe cations in interstitial sites. The bulk defect chemistry is dominated by cation vacancies and interstitials (not oxygen vacancies) and this provides the context to understand iron oxide surfaces, which represent the front line in reduction and oxidation processes. Fe diffuses in and out from the bulk in response to the O2 chemical potential, forming sometimes complex intermediate phases at the surface. For example, α-Fe2O3 adopts Fe3O4-like surfaces in reducing conditions, and Fe3O4 adopts Fe1-xO-like structures in further reducing conditions still. It is argued that known bulk defect structures are an excellent starting point in building models for iron oxide surfaces. The atomic-scale structure of the low-index surfaces of iron oxides is the major focus of this review. Fe3O4 is the most studied iron oxide in surface science, primarily because its stability range corresponds nicely to the ultra-high vacuum environment. It is also an electrical conductor, which makes it straightforward to study with the most commonly used surface science methods such as photoemission spectroscopies (XPS, UPS) and scanning tunneling microscopy (STM). The impact of the surfaces on the measurement of bulk properties such as magnetism, the Verwey transition and the (predicted) half-metallicity is discussed. The best understood iron oxide surface at present is probably Fe3O4(100); the structure is

  2. Oxidative desulfurization of diesel with TBHP/isobutyl aldehyde/air oxidation system

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Wei; Wang, Chengyong; Lin, Peng; Lu, Xiaoping [Institute of Sonochemical Engineering, Nanjing University of Technology, Nanjing 210009, Jiangsu (China)

    2011-01-15

    Oxidative desulfurization of hydrogenation diesel (40 mL) was studied using air as oxidant, tert-butyl hydroperoxide (TBHP) as radical initiator at ambient pressure and moderate temperature in the presence of isobutyl aldehyde. TBHP could accelerate the production of carbonyl radical and its peroxidation. When the molar fraction of TBHP was 5 mmol, the conversion of DBT could reach 96.1% in the present of 20 mmol isobutyl aldehyde and air, which was more than that of 85.5% without initiator. The air was an effective oxidant and acetonitrile was an optimal solvent in this process. The sulfur content of the hydrogenation diesel could be reduced from 403 to 13 ppm (96.8% removed) under the synergistic effect of air, TBHP and isobutyl aldehyde. (author)

  3. Oxide, interface, and border traps in thermal, N2O, and N2O-nitrided oxides

    International Nuclear Information System (INIS)

    Fleetwood, D.M.; Saks, N.S.

    1996-01-01

    We have combined thermally stimulated-current (TSC) and capacitance endash voltage (C endash V) measurements to estimate oxide, interface, and effective border trap densities in 6 endash 23 nm thermal, N 2 O, and N 2 O-nitrided oxides exposed to ionizing radiation or high-field electron injection. Defect densities depend strongly on oxide processing, but radiation exposure and moderate high-field stress lead to similar trapped hole peak thermal energy distributions (between ∼1.7 and ∼2.0 eV) for all processes. This suggests that similar defects dominate the oxide charge trapping properties in these devices. Radiation-induced hole and interface trap generation efficiencies (0.1%endash 1%) in the best N 2 O and N 2 O-nitrided oxides are comparable to the best radiation hardened oxides in the literature. After ∼10 Mrad(SiO 2 ) x-ray irradiation or ∼10 mC/cm 2 constant current Fowler endash Nordheim injection, effective border trap densities as high as ∼5x10 11 cm -2 are inferred from C endash V hysteresis. These measurements suggest irradiation and high-field stress cause similar border trap energy distributions. In each case, even higher densities of compensating trapped electrons in the oxides (up to 2x10 12 cm -2 ) are inferred from combined TSC and C endash V measurements. These trapped electrons prevent conventional C endash V methods from providing accurate estimates of the total oxide trap charge density in many irradiation or high-field stress studies. Fewer compensating electrons per trapped hole (∼26%±5%) are found for irradiation of N 2 O and N 2 O-nitrided oxides than for thermal oxides (∼46%±7%). (Abstract Truncated)

  4. Reducible oxide based catalysts

    Science.gov (United States)

    Thompson, Levi T.; Kim, Chang Hwan; Bej, Shyamal K.

    2010-04-06

    A catalyst is disclosed herein. The catalyst includes a reducible oxide support and at least one noble metal fixed on the reducible oxide support. The noble metal(s) is loaded on the support at a substantially constant temperature and pH.

  5. Association of Oxidative Stress with Psychiatric Disorders.

    Science.gov (United States)

    Hassan, Waseem; Noreen, Hamsa; Castro-Gomes, Vitor; Mohammadzai, Imdadullah; da Rocha, Joao Batista Teixeira; Landeira-Fernandez, J

    2016-01-01

    When concentrations of both reactive oxygen species and reactive nitrogen species exceed the antioxidative capability of an organism, the cells undergo oxidative impairment. Impairments in membrane integrity and lipid and protein oxidation, protein mutilation, DNA damage, and neuronal dysfunction are some of the fundamental consequences of oxidative stress. The purpose of this work was to review the associations between oxidative stress and psychological disorders. The search terms were the following: "oxidative stress and affective disorders," "free radicals and neurodegenerative disorders," "oxidative stress and psychological disorders," "oxidative stress, free radicals, and psychiatric disorders," and "association of oxidative stress." These search terms were used in conjunction with each of the diagnostic categories of the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders and World Health Organization's International Statistical Classification of Diseases and Related Health Problems. Genetic, pharmacological, biochemical, and preclinical therapeutic studies, case reports, and clinical trials were selected to explore the molecular aspects of psychological disorders that are associated with oxidative stress. We identified a broad spectrum of 83 degenerative syndromes and psychiatric disorders that were associated with oxidative stress. The multi-dimensional information identified herein supports the role of oxidative stress in various psychiatric disorders. We discuss the results from the perspective of developing novel therapeutic interventions.

  6. Accelerated evaporation of water on graphene oxide.

    Science.gov (United States)

    Wan, Rongzheng; Shi, Guosheng

    2017-03-29

    Using molecular dynamics simulations, we show that the evaporation of nanoscale volumes of water on patterned graphene oxide is faster than that on homogeneous graphene oxide. The evaporation rate of water is insensitive to variation in the oxidation degree of the oxidized regions, so long as the water film is only distributed on the oxidized regions. The evaporation rate drops when the water film spreads onto the unoxidized regions. Further analysis showed that varying the oxidation degree observably changed the interaction between the outmost water molecules and the solid surface, but the total interaction for the outmost water molecules only changed a very limited amount due to the correspondingly regulated water-water interaction when the water film is only distributed on the oxidized regions. When the oxidation degree is too low and some unoxidized regions are also covered by the water film, the thickness of the water film decreases, which extends the lifetime of the hydrogen bonds for the outmost water molecules and lowers the evaporation rate of the water. The insensitivity of water evaporation to the oxidation degree indicates that we only need to control the scale of the unoxidized and oxidized regions for graphene oxide to regulate the evaporation of nanoscale volumes of water.

  7. Pyrite oxidation at circumneutral pH

    Science.gov (United States)

    Moses, Carl O.; Herman, Janet S.

    1991-02-01

    Previous studies of pyrite oxidation kinetics have concentrated primarily on the reaction at low pH, where Fe(III) has been assumed to be the dominant oxidant. Studies at circumneutral pH, necessitated by effective pH buffering in some pyrite oxidation systems, have often implicitly assumed that the dominant oxidant must be dissolved oxygen (DO), owing to the diminished solubility of Fe(III). In fact, Fe(III)(aq) is an effective pyrite oxidant at circumneutral pH, but the reaction cannot be sustained in the absence of DO. The purpose of this experimental study was to ascertain the relative roles of Fe(III) and DO in pyrite oxidation at circumneutral pH. The rate of pyrite oxidation was first-order with respect to the ratio of surface area to solution volume. Direct determinations of both Fe(II) (aq)> and Fe(III) (aq) demonstrated a dramatic loss of Fe(II) from the solution phase in excess of the loss for which oxidation alone could account. Based on rate data, we have concluded that Fe(II) is adsorbed onto the pyrite surface. Furthermore, Fe(II) is preferred as an adsorbate to Fe(III), which we attribute to both electrostatic and acid-base selectivity. We also found that the rate of pyrite oxidation by either Fe(III) (aq) or DO is reduced in the presence of aqueous Fe(II), which leads us to conclude that, under most natural conditions, neither Fe(III) (aq) nor DO directly attacks the pyrite surface. The present evidence suggests a mechanism for pyrite oxidation that involves adsorbed Fe( II ) giving up electrons to DO and the resulting Fe(III) rapidly accepting electrons from the pyrite. The adsorbed Fe is, thus, cyclically oxidized and reduced, while it acts as a conduit for electrons traveling from pyrite to DO. Oxygen is transferred from the hydration sphere of the adsorbed Fe to pyrite S. The cycle of adsorbed Fe oxidation and reduction and the successive addition of oxygen to pyrite S continues until a stable sulfoxy species dissociates from the surface. Prior

  8. Ni–Ta–O mixed oxide catalysts for the low temperature oxidative dehydrogenation of ethane to ethylene

    KAUST Repository

    Zhu, Haibo

    2015-09-01

    The "wet" sol-gel and "dry" solid-state methods were used to prepare Ni-Ta-O mixed oxide catalysts. The resulting Ni-Ta oxides exhibit high activity and selectivity for the low temperature oxidative dehydrogenation of ethane to ethylene. The Ta/(Ni + Ta) atomic ratios (varying from 0 to 0.11 in "wet" sol-gel method, and from 0 to 0.20 in "dry" solid-state method) as well as the preparation methods used in the synthesis, play important roles in controlling catalyst structure, activity, selectivity and stability in the oxidative dehydrogenation of ethane. Electron microscopy characterizations (TEM, EELS mapping, and HAADF-STEM) clearly demonstrate that the Ta atoms are inserted into NiO crystal lattice, resulting in the formation of a new Ni-Ta oxide solid solution. More Ta atoms are found to be located at the lattice sites of crystal surface in sol-gel catalyst. While, a small amount of thin layer of Ta2O5 clusters are detected in solid-state catalyst. Further characterization by XRD, N2 adsorption, SEM, H2-TPR, XPS, and Raman techniques reveal different properties of these two Ni-Ta oxides. Due to the different properties of the Ni-Ta oxide catalysts prepared by two distinct approaches, they exhibit different catalytic behaviors in the ethane oxidative dehydrogenation reaction at low temperature. Thus, the catalytic performance of Ni-Ta-O mixed oxide catalysts can be systematically modified and tuned by selecting a suitable synthesis method, and then varying the Ta content. ©2015 Elsevier Inc. All rights reserved.

  9. VUV photo-oxidation of gaseous benzene combined with ozone-assisted catalytic oxidation: Effect on transition metal catalyst

    Science.gov (United States)

    Huang, Haibao; Lu, Haoxian; Zhan, Yujie; Liu, Gaoyuan; Feng, Qiuyu; Huang, Huiling; Wu, Muyan; Ye, Xinguo

    2017-01-01

    Volatile organic compounds (VOCs) cause the major air pollution concern. In this study, a series of ZSM-5 supported transition metals were prepared by impregnation method. They were combined with vacuum UV (VUV) photo-oxidation in a continuous-flow packed-bed reactor and used for the degradation of benzene, a typical toxic VOCs. Compared with VUV photo-oxidation alone, the introduction of catalysts can greatly enhance benzene oxidation under the help of O3, the by-products from VUV irradiation, via ozone-assisted catalytic oxidation (OZCO). The catalytic activity of transition metals towards benzene oxidation followed the order: Mn > Co > Cu > Ni > Fe. Mn achieved the best catalytic activity due to the strongest capability for O3 catalytic decomposition and utilization. Benzene and O3 removal efficiency reached as high as 97% and 100% after 360 min, respectively. O3 was catalytically decomposed, generating highly reactive oxidants such as rad OH and rad O for benzene oxidation.

  10. d° Ferromagnetism of Magnesium Oxide

    Directory of Open Access Journals (Sweden)

    Jitendra Pal Singh

    2017-11-01

    Full Text Available Magnetism without d-orbital electrons seems to be unrealistic; however, recent observations of magnetism in non-magnetic oxides, such as ZnO, HfO2, and MgO, have opened new avenues in the field of magnetism. Magnetism exhibited by these oxides is known as d° ferromagnetism, as these oxides either have completely filled or unfilled d-/f-orbitals. This magnetism is believed to occur due to polarization induced by p-orbitals. Magnetic polarization in these oxides arises due to vacancies, the excitation of trapped spin in the triplet state. The presence of vacancies at the surface and subsurface also affects the magnetic behavior of these oxides. In the present review, origins of magnetism in magnesium oxide are discussed to obtain understanding of d° ferromagnetism.

  11. Formation of iron oxides from acid mine drainage and magnetic separation of the heavy metals adsorbed iron oxides

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Hee Won; Kim, Jeong Jin; Kim, Young Hun [Andong National University, Andong (Korea, Republic of); Ha, Dong Woo [Korea Electrotechnology Research Institute, Changwon (Korea, Republic of)

    2016-03-15

    There are a few thousand abandoned metal mines in South Korea. The abandoned mines cause several environmental problems including releasing acid mine drainage (AMD), which contain a very high acidity and heavy metal ions such as Fe, Cu, Cd, Pb, and As. Iron oxides can be formed from the AMD by increasing the solution pH and inducing precipitation. Current study focused on the formation of iron oxide in an AMD and used the oxide for adsorption of heavy metals. The heavy metal adsorbed iron oxide was separated with a superconducting magnet. The duration of iron oxide formation affected on the type of mineral and the degree of magnetization. The removal rate of heavy metal by the adsorption process with the formed iron oxide was highly dependent on the type of iron oxide and the solution pH. A high gradient magnetic separation (HGMS) system successfully separated the iron oxide and harmful heavy metals.

  12. Production of oceanic nitrous oxide by ammonia-oxidizing archaea

    Directory of Open Access Journals (Sweden)

    C. R. Löscher

    2012-07-01

    Full Text Available The recent finding that microbial ammonia oxidation in the ocean is performed by archaea to a greater extent than by bacteria has drastically changed the view on oceanic nitrification. The numerical dominance of archaeal ammonia-oxidizers (AOA over their bacterial counterparts (AOB in large parts of the ocean leads to the hypothesis that AOA rather than AOB could be the key organisms for the oceanic production of the strong greenhouse gas nitrous oxide (N2O that occurs as a by-product of nitrification. Very recently, enrichment cultures of marine ammonia-oxidizing archaea have been reported to produce N2O.

    Here, we demonstrate that archaeal ammonia monooxygenase genes (amoA were detectable throughout the water column of the eastern tropical North Atlantic (ETNA and eastern tropical South Pacific (ETSP Oceans. Particularly in the ETNA, comparable patterns of abundance and expression of archaeal amoA genes and N2O co-occurred in the oxygen minimum, whereas the abundances of bacterial amoA genes were negligible. Moreover, selective inhibition of archaea in seawater incubations from the ETNA decreased the N2O production significantly. In studies with the only cultivated marine archaeal ammonia-oxidizer Nitrosopumilus maritimus SCM1, we provide the first direct evidence for N2O production in a pure culture of AOA, excluding the involvement of other microorganisms as possibly present in enrichments. N. maritimus showed high N2O production rates under low oxygen concentrations comparable to concentrations existing in the oxycline of the ETNA, whereas the N2O production from two AOB cultures was comparably low under similar conditions. Based on our findings, we hypothesize that the production of N2O in tropical ocean areas results mainly from archaeal nitrification and will be affected by the predicted decrease in dissolved

  13. Reversible solid oxide fuel cells (R-SOFCs) with chemically stable proton-conducting oxides

    KAUST Repository

    Bi, Lei; Boulfrad, Samir; Traversa, Enrico

    2015-01-01

    Proton-conducting oxides offer a promising way of lowering the working temperature of solid oxide cells to the intermediate temperate range (500 to 700. °C) due to their better ionic conductivity. In addition, the application of proton

  14. Mechanistic insight into oxide-promoted palladium catalysts for the electro-oxidation of ethanol.

    Science.gov (United States)

    Martinez, Ulises; Serov, Alexey; Padilla, Monica; Atanassov, Plamen

    2014-08-01

    Recent advancements in the development of alternatives to proton exchange membrane fuel cells utilizing less-expensive catalysts and renewable liquid fuels, such as alcohols, has been observed for alkaline fuel cell systems. Alcohol fuels present the advantage of not facing the challenge of storage and transportation encountered with hydrogen fuel. Oxidation of alcohols has been improved by the promotion of alloyed or secondary phases. Nevertheless, currently, there is no experimental understanding of the difference between an intrinsic and a synergistic promotion effect in high-pH environments. This report shows evidence of different types of promotion effects on palladium electrocatalysts obtained from the presence of an oxide phase for the oxidation of ethanol. The correlation of mechanistic in situ IR spectroscopic studies with electrochemical voltammetry studies on two similar electrocatalytic systems allow the role of either an alloyed or a secondary phase on the mechanism of oxidation of ethanol to be elucidated. Evidence is presented for the difference between an intrinsic effect obtained from an alloyed system and a synergistic effect produced by the presence of an oxide phase. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. SOIL NITROUS OXIDE, NITRIC OXIDE, AND AMMONIA EMISSIONS FROM A RECOVERING RIPARIAN ECOSYSTEM IN SOUTHERN APPALACHIA

    Science.gov (United States)

    The paper presents two years of seasonal nitric oxide, ammonia, and nitrous oxide trace gas fluxes measured in a recovering riparian zone with cattle excluded and in an adjacent riparian zone grazed by cattle. In the recovering riparian zone, average nitric oxide, ammonia, and ni...

  16. Differential contributions of ammonia oxidizers and nitrite oxidizers to nitrification in four paddy soils

    Science.gov (United States)

    Wang, Baozhan; Zhao, Jun; Guo, Zhiying; Ma, Jing; Xu, Hua; Jia, Zhongjun

    2015-01-01

    Rice paddy fields are characterized by regular flooding and nitrogen fertilization, but the functional importance of aerobic ammonia oxidizers and nitrite oxidizers under unique agricultural management is poorly understood. In this study, we report the differential contributions of ammonia-oxidizing archaea (AOA), bacteria (AOB) and nitrite-oxidizing bacteria (NOB) to nitrification in four paddy soils from different geographic regions (Zi-Yang (ZY), Jiang-Du (JD), Lei-Zhou (LZ) and Jia-Xing (JX)) that are representative of the rice ecosystems in China. In urea-amended microcosms, nitrification activity varied greatly with 11.9, 9.46, 3.03 and 1.43 μg NO3−-N g−1 dry weight of soil per day in the ZY, JD, LZ and JX soils, respectively, over the course of a 56-day incubation period. Real-time quantitative PCR of amoA genes and pyrosequencing of 16S rRNA genes revealed significant increases in the AOA population to various extents, suggesting that their relative contributions to ammonia oxidation activity decreased from ZY to JD to LZ. The opposite trend was observed for AOB, and the JX soil stimulated only the AOB populations. DNA-based stable-isotope probing further demonstrated that active AOA numerically outcompeted their bacterial counterparts by 37.0-, 10.5- and 1.91-fold in 13C-DNA from ZY, JD and LZ soils, respectively, whereas AOB, but not AOA, were labeled in the JX soil during active nitrification. NOB were labeled to a much greater extent than AOA and AOB, and the addition of acetylene completely abolished the assimilation of 13CO2 by nitrifying populations. Phylogenetic analysis suggested that archaeal ammonia oxidation was predominantly catalyzed by soil fosmid 29i4-related AOA within the soil group 1.1b lineage. Nitrosospira cluster 3-like AOB performed most bacterial ammonia oxidation in the ZY, LZ and JX soils, whereas the majority of the 13C-AOB in the JD soil was affiliated with the Nitrosomona communis lineage. The 13C-NOB was overwhelmingly

  17. Bismuth iron oxide thin films using atomic layer deposition of alternating bismuth oxide and iron oxide layers

    Energy Technology Data Exchange (ETDEWEB)

    Puttaswamy, Manjunath; Vehkamäki, Marko [University of Helsinki, Department of Chemistry, P.O. Box 55, FI-00014 Helsinki (Finland); Kukli, Kaupo, E-mail: kaupo.kukli@helsinki.fi [University of Helsinki, Department of Chemistry, P.O. Box 55, FI-00014 Helsinki (Finland); University of Tartu, Institute of Physics, W. Ostwald 1, EE-50411 Tartu (Estonia); Dimri, Mukesh Chandra [National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, EE-12618 Tallinn (Estonia); Kemell, Marianna; Hatanpää, Timo; Heikkilä, Mikko J. [University of Helsinki, Department of Chemistry, P.O. Box 55, FI-00014 Helsinki (Finland); Mizohata, Kenichiro [University of Helsinki, Department of Physics, P.O. Box 64, FI-00014 Helsinki (Finland); Stern, Raivo [National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, EE-12618 Tallinn (Estonia); Ritala, Mikko; Leskelä, Markku [University of Helsinki, Department of Chemistry, P.O. Box 55, FI-00014 Helsinki (Finland)

    2016-07-29

    Bismuth iron oxide films with varying contributions from Fe{sub 2}O{sub 3} or Bi{sub 2}O{sub 3} were prepared using atomic layer deposition. Bismuth (III) 2,3-dimethyl-2-butoxide, was used as the bismuth source, iron(III) tert-butoxide as the iron source and water vapor as the oxygen source. The films were deposited as stacks of alternate Bi{sub 2}O{sub 3} and Fe{sub 2}O{sub 3} layers. Films grown at 140 °C to the thickness of 200–220 nm were amorphous, but crystallized upon post-deposition annealing at 500 °C in nitrogen. Annealing of films with intermittent bismuth and iron oxide layers grown to different thicknesses influenced their surface morphology, crystal structure, composition, electrical and magnetic properties. Implications of multiferroic performance were recognized in the films with the remanent charge polarization varying from 1 to 5 μC/cm{sup 2} and magnetic coercivity varying from a few up to 8000 A/m. - Highlights: • Bismuth iron oxide thin films were grown by atomic layer deposition at 140 °C. • The major phase formed in the films upon annealing at 500 °C was BiFeO{sub 3}. • BiFeO{sub 3} films and films containing excess Bi favored electrical charge polarization. • Slight excess of iron oxide enhanced saturative magnetization behavior.

  18. Determination of Ammonia Oxidizing Bacteria and Nitrate Oxidizing Bacteria in Wastewater and Bioreactors

    Science.gov (United States)

    Francis, Somilez Asya

    2014-01-01

    The process of water purification has many different physical, chemical, and biological processes. One part of the biological process is the task of ammonia oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB). Both play critical roles in the treatment of wastewater by oxidizing toxic compounds. The broad term is nitrification, a naturally occurring process that is carried out by AOB and NOB by using oxidation to convert ammonia to nitrite and nitrite to nitrate. To monitor this biological activity, bacterial staining was performed on wastewater contained in inoculum tanks and biofilm samples from bioreactors. Using microscopy and qPCR, the purpose of this experiment was to determine if the population of AOB and NOB in wastewater and membrane bioreactors changed depending on temperature and hibernation conditions to determine the optimal parameters for AOB/NOB culture to effectively clean wastewater.

  19. Distribution of antimony in the oxide layer formed by potentiostatic oxidation of Pb-Sb alloy

    Energy Technology Data Exchange (ETDEWEB)

    Arifuku, F.; Yoneyama, H.; Tamura, H.

    1979-09-01

    The distribution of antimony within the oxide films on Pb-Sb alloy prepared by potentiostatic oxidation in H/sub 2/SO/sub 4/ solutions was examined by SIMS. The study of oxide films prepared by applying different potentials for three hours showed that two types of film were obtained depending on whether the potential was more negative or more positive than 1.5 V. Antimony profiles were obtained for films at several stages in the initial growth. It was found that antimony was retained in the oxide film at 1.5 V during both nucleation and two- or three-dimensional growth of PbO/sub 2/ and at 1.6 V during the lateral overlaps of three-dimensional centers of PbO/sub 2/. Relationships between the antimony distribution profiles and the oxide film growth are discussed. 8 figures, 1 table.

  20. VUV photo-oxidation of gaseous benzene combined with ozone-assisted catalytic oxidation: Effect on transition metal catalyst

    International Nuclear Information System (INIS)

    Huang, Haibao; Lu, Haoxian; Zhan, Yujie; Liu, Gaoyuan; Feng, Qiuyu; Huang, Huiling; Wu, Muyan; Ye, Xinguo

    2017-01-01

    Graphical abstract: Mn nanoparticles are highly dispersed on ZSM-5 and most efficient in benzene degradation in the VUV-OZCO process. - Highlights: • Vacuum UV irradiation is well combined with O_3 catalytic oxidation. • O_3 byproducts was used to enhance catalytic oxidation of VOCs. • Mn/ZSM-5 achieved the best catalytic activity for benzene degradation. - Abstract: Volatile organic compounds (VOCs) cause the major air pollution concern. In this study, a series of ZSM-5 supported transition metals were prepared by impregnation method. They were combined with vacuum UV (VUV) photo-oxidation in a continuous-flow packed-bed reactor and used for the degradation of benzene, a typical toxic VOCs. Compared with VUV photo-oxidation alone, the introduction of catalysts can greatly enhance benzene oxidation under the help of O_3, the by-products from VUV irradiation, via ozone-assisted catalytic oxidation (OZCO). The catalytic activity of transition metals towards benzene oxidation followed the order: Mn > Co > Cu > Ni > Fe. Mn achieved the best catalytic activity due to the strongest capability for O_3 catalytic decomposition and utilization. Benzene and O_3 removal efficiency reached as high as 97% and 100% after 360 min, respectively. O_3 was catalytically decomposed, generating highly reactive oxidants such as ·OH and ·O for benzene oxidation.

  1. VUV photo-oxidation of gaseous benzene combined with ozone-assisted catalytic oxidation: Effect on transition metal catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Haibao, E-mail: seabao8@gmail.com [School of Environmental Science and Engineering, Sun Yat-Sen University (China); Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology (Sun Yat-sen University) (China); Lu, Haoxian; Zhan, Yujie; Liu, Gaoyuan; Feng, Qiuyu; Huang, Huiling; Wu, Muyan; Ye, Xinguo [School of Environmental Science and Engineering, Sun Yat-Sen University (China)

    2017-01-01

    Graphical abstract: Mn nanoparticles are highly dispersed on ZSM-5 and most efficient in benzene degradation in the VUV-OZCO process. - Highlights: • Vacuum UV irradiation is well combined with O{sub 3} catalytic oxidation. • O{sub 3} byproducts was used to enhance catalytic oxidation of VOCs. • Mn/ZSM-5 achieved the best catalytic activity for benzene degradation. - Abstract: Volatile organic compounds (VOCs) cause the major air pollution concern. In this study, a series of ZSM-5 supported transition metals were prepared by impregnation method. They were combined with vacuum UV (VUV) photo-oxidation in a continuous-flow packed-bed reactor and used for the degradation of benzene, a typical toxic VOCs. Compared with VUV photo-oxidation alone, the introduction of catalysts can greatly enhance benzene oxidation under the help of O{sub 3}, the by-products from VUV irradiation, via ozone-assisted catalytic oxidation (OZCO). The catalytic activity of transition metals towards benzene oxidation followed the order: Mn > Co > Cu > Ni > Fe. Mn achieved the best catalytic activity due to the strongest capability for O{sub 3} catalytic decomposition and utilization. Benzene and O{sub 3} removal efficiency reached as high as 97% and 100% after 360 min, respectively. O{sub 3} was catalytically decomposed, generating highly reactive oxidants such as ·OH and ·O for benzene oxidation.

  2. Zinc-oxide nanorod / copper-oxide thin-film heterojunction for a nitrogen-monoxide gas sensor

    International Nuclear Information System (INIS)

    Yoo, Hwansu; Kim, Hyojin; Kim, Dojin

    2014-01-01

    A novel p - n oxide heterojunction structure was fabricated by employing n-type zinc-oxide (ZnO) nanorods grown on an indium-tin-oxide-coated glass substrate by using the hydrothermal method and a p-type copper-oxide (CuO) thin film deposited onto the ZnO nanorod array by using the sputtering method. The crystallinities and microstructures of the heterojunction materials were examined by using X-ray diffraction and scanning electron microscopy. The observed current - voltage characteristics of the p - n oxide heterojunction showed a nonlinear diode-like rectifying behavior. The effects of an oxidizing or electron acceptor gas, such as nitrogen monoxide (NO), on the ZnO nanorod/CuO thin-film heterojunction were investigated to determine the potential applications of the fabricated material for use in gas sensors. The forward current of the p - n heterojunction was remarkably reduced when NO gas was introduced into dry air at temperatures from 100 to 250 .deg. C. The NO gas response of the oxide heterojunction reached a maximum value at an operating temperature of 180 .deg. C and linearly increased as the NO gas concentration was increased from 5 to 30 ppm. The sensitivity value was observed to be as high as 170% at 180 .deg. C when biased at 2 V in the presence of 20-ppm NO. The ZnO nanorod/CuO thin-film heterojunction also exhibited a stable and repeatable response to NO gas. The experimental results suggest that the ZnO nanorod/CuO thin-film heterojunction structure may be a novel candidate for gas sensors.

  3. Zinc-oxide nanorod / copper-oxide thin-film heterojunction for a nitrogen-monoxide gas sensor

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Hwansu; Kim, Hyojin; Kim, Dojin [Chungnam National University, Daejeon (Korea, Republic of)

    2014-11-15

    A novel p - n oxide heterojunction structure was fabricated by employing n-type zinc-oxide (ZnO) nanorods grown on an indium-tin-oxide-coated glass substrate by using the hydrothermal method and a p-type copper-oxide (CuO) thin film deposited onto the ZnO nanorod array by using the sputtering method. The crystallinities and microstructures of the heterojunction materials were examined by using X-ray diffraction and scanning electron microscopy. The observed current - voltage characteristics of the p - n oxide heterojunction showed a nonlinear diode-like rectifying behavior. The effects of an oxidizing or electron acceptor gas, such as nitrogen monoxide (NO), on the ZnO nanorod/CuO thin-film heterojunction were investigated to determine the potential applications of the fabricated material for use in gas sensors. The forward current of the p - n heterojunction was remarkably reduced when NO gas was introduced into dry air at temperatures from 100 to 250 .deg. C. The NO gas response of the oxide heterojunction reached a maximum value at an operating temperature of 180 .deg. C and linearly increased as the NO gas concentration was increased from 5 to 30 ppm. The sensitivity value was observed to be as high as 170% at 180 .deg. C when biased at 2 V in the presence of 20-ppm NO. The ZnO nanorod/CuO thin-film heterojunction also exhibited a stable and repeatable response to NO gas. The experimental results suggest that the ZnO nanorod/CuO thin-film heterojunction structure may be a novel candidate for gas sensors.

  4. Heterogeneous oxidation of SO2 by O3-aged black carbon and its dithiothreitol oxidative potential.

    Science.gov (United States)

    Xu, Weiwei; Li, Qian; Shang, Jing; Liu, Jia; Feng, Xiang; Zhu, Tong

    2015-10-01

    Ozone (O3) is an important atmospheric oxidant. Black carbon (BC) particles released into the atmosphere undergo an aging process via O3 oxidation. O3-aged BC particles may change their uptake ability toward trace reducing gases such as SO2 in the atmosphere, leading to different environmental and health effects. In this paper, the heterogeneous reaction process between O3-aged BC and SO2 was explored via in-situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). Combined with ion chromatography (IC), DRIFTS was used to qualitatively and quantitatively analyze the sulfate product. The results showed that O3-aged BC had stronger SO2 oxidation ability than fresh BC, and the reactive species/sites generated on the surface had an important role in the oxidation of SO2. Relative humidity or 254nm UV (ultraviolet) light illumination enhanced the oxidation uptake of SO2 on O3-aged BC. The oxidation potentials of the BC particles were detected via dithiothreitol (DTT) assay. The DTT activity over BC was decreased in the process of SO2 reduction, with the consumption of oxidative active sites. Copyright © 2015. Published by Elsevier B.V.

  5. Treatment of Fatty Acid Oxidation Disorders

    Science.gov (United States)

    ... Treatment of fatty acid oxidation disorders Treatment of fatty acid oxidation disorders E-mail to a friend Please ... this page It's been added to your dashboard . Fatty acid oxidation disorders are rare health conditions that affect ...

  6. Bi-template assisted synthesis of mesoporous manganese oxide nanostructures: Tuning properties for efficient CO oxidation.

    Science.gov (United States)

    Roy, Mouni; Basak, Somjyoti; Naskar, Milan Kanti

    2016-02-21

    A simple soft bi-templating process was used for the synthesis of mesoporous manganese oxide nanostructures using KMnO4 as a precursor and polyethylene glycol and cetyltrimethylammonium bromide as templates in the presence of benzaldehyde as an organic additive in alkaline media, followed by calcination at 400 °C. X-ray diffraction and Raman spectroscopic analysis of the calcined products confirmed the existence of stoichiometric (MnO2 and Mn5O8) and non-stoichiometric mixed phases (MnO2 + Mn5O8) of Mn oxides obtained by tuning the concentration of the additive and the synthesis time. The surface properties of the prepared Mn oxides were determined by X-ray photoelectron spectroscopy. The mesoporosity of the samples was confirmed by N2 adsorption-desorption. Different synthetic conditions resulted in the formation of different morphologies of the Mn oxides (α-MnO2, Mn5O8, and α-MnO2 + Mn5O8), such as nanoparticles, nanorods, and nanowires. The synthesized mesoporous Mn oxide nanostructures were used for the catalytic oxidation of the harmful air pollutant carbon monoxide. The Mn5O8 nanoparticles with the highest Brunauer-Emmett-Teller surface area and the non-stoichiometric manganese oxide (α-MnO2 + Mn5O8) nanorods with a higher Mn(3+) concentration had the best catalytic efficiency.

  7. Superparamagnetic iron oxides for MRI

    International Nuclear Information System (INIS)

    Weissleder, R.; Reimer, P.

    1993-01-01

    Pharmaceutical iron oxide preparations have been used as MRI contrast agents for a variety of purposes. These agents predominantly decrease T2 relaxation times and therefore cause a decrease in signal intensity of tissues that contain the agent. After intravenous administration, dextran-coated iron oxides typically accumulate in phagocytic cells in liver and spleen. Clinical trials have shown that iron oxide increases lesion/liver and lesion/spleen contrast, that more lesions can be depicted than on plain MRI or CT, and that the size threshold for lesion detection decreases. Decreased uptake of iron oxides in liver has been observed in hepatitis and cirrhosis, potentially allowing the assessment of organ function. More recently a variety of novel, target-specific monocrystalline iron oxides compounds have been used for receptor and immunospecific images. Future development of targeted MRI contrast agents is critical for organ- or tissue-specific quantitative and functional MRI. (orig.)

  8. Superparamagnetic iron oxides for MRI

    Energy Technology Data Exchange (ETDEWEB)

    Weissleder, R [MGH-NMR Center, Dept. of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA (United States); Reimer, P [MGH-NMR Center, Dept. of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA (United States); [Inst. fuer Klinische Radiologie, Zentrale Roentgendiagnostik, Westfaelische-Wilhelms-Univ., Muenster (Germany)

    1993-06-01

    Pharmaceutical iron oxide preparations have been used as MRI contrast agents for a variety of purposes. These agents predominantly decrease T2 relaxation times and therefore cause a decrease in signal intensity of tissues that contain the agent. After intravenous administration, dextran-coated iron oxides typically accumulate in phagocytic cells in liver and spleen. Clinical trials have shown that iron oxide increases lesion/liver and lesion/spleen contrast, that more lesions can be depicted than on plain MRI or CT, and that the size threshold for lesion detection decreases. Decreased uptake of iron oxides in liver has been observed in hepatitis and cirrhosis, potentially allowing the assessment of organ function. More recently a variety of novel, target-specific monocrystalline iron oxides compounds have been used for receptor and immunospecific images. Future development of targeted MRI contrast agents is critical for organ- or tissue-specific quantitative and functional MRI. (orig.)

  9. Growth and thermal oxidation of Ru and ZrO2 thin films as oxidation protective layers

    NARCIS (Netherlands)

    Coloma Ribera, R.

    2017-01-01

    This thesis focuses on the study of physical and chemical processes occurring during growth and thermal oxidation of Ru and ZrO2 thin films. Acting as oxidation resistant capping materials to prevent oxidation of layers underneath, these films have several applications, i.e., in microelectronics

  10. Test Concept for Advanced Oxidation Techniques

    DEFF Research Database (Denmark)

    Bennedsen, Lars Rønn; Søgaard, Erik Gydesen; Mortensen, Lars

    advanced on-site oxidation tests. The remediation techniques included are electrochemical oxidation, photochemical/photocatalytic oxidation, ozone, hydrogen peroxide, permanganate, and persulfate among others. A versatile construction of the mobile test unit makes it possible to combine different...

  11. Segregation across the metal/oxide interface occurring during oxidation at high temperatures of diluted iron based alloys

    International Nuclear Information System (INIS)

    Geneve, D.; Rouxel, D.; Weber, B.; Confente, M.

    2006-01-01

    Industrial steels being elaborated in air at high temperature oxidize and cover with a complex oxide layer. The oxidation reaction drastically alters the surface composition. Such modifications have been investigated, in this work, by Auger Electron Spectroscopy (AES) using an original method to characterize the composition of the metal/oxide interfaces. Analysis of the concentration gradients across the interfaces allows to better understand how the alloy elements contribute to the oxidation process. The development of new alloy phases, the interdependencies between elements and the diffusion of different species are discussed considering thermodynamic properties of each element

  12. Causas de decomiso en un matadero porcino industrial en el Norte de España

    OpenAIRE

    Ruiz Alonso, Alejandro

    2017-01-01

    El sector porcino español es el cuarto más importante del mundo, además de suponer un gran volumen de exportaciones tanto a la Unión Europea como a terceros países. Debido a esto es importante conocer y comprender las principales causas de decomiso ya que causan importantes pérdidas económicas tanto a granjas como industrias y en algunos casos pueden comprometer el estatus sanitario de la población humana. Para realizar el estudio se contó con la colaboración del SVO, que proporcionó los dato...

  13. Crystallization inhibitors for amorphous oxides

    International Nuclear Information System (INIS)

    Reznitskij, L.A.; Filippova, S.E.

    1993-01-01

    Data for the last 10 years, in which experimental results of studying the temperature stabilization of x-ray amorphous oxides (including R 3 Fe 5 O 12 R-rare earths, ZrO 2 , In 2 O 3 , Sc 2 O 3 ) and their solid solution are presented, are generalized. Processes of amorphous oxide crystallization with the production of simple oxides, solid solutions and chemical compounds with different polyhedral structure, are investigated. Energy and crystallochemical criteria for selecting the doping inhibitor-components stabilizing the amorphous state are ascertained, temperatures and enthalpies of amorpous oxide crystallization are determined, examination of certain provisions of iso,orphous miscibility theory is conducted

  14. Fundamental Studies of Butane Oxidation over Model-Supported Vanadium Oxide Catalysts: Molecular Structure-Reactivity Relationships

    NARCIS (Netherlands)

    Wachs, I.E.; Jehng, J.M.; Deo, G.; Weckhuysen, B.M.; Guliants, V.V.; Benziger, J.B.; Sundaresan, S.

    1997-01-01

    The oxidation of n-butane to maleic anhydride was investigated over a series of model-supported vanadia catalysts where the vanadia phase was present as a two-dimensional metal oxide overlayer on the different oxide supports (TiO2, ZrO2, CeO2, Nb2O5, Al2O3, and SiO2). No correlation was found

  15. Potassium/calcium/nickel oxide catalysts for the oxidative coupling of methane

    NARCIS (Netherlands)

    Dooley, K.; Dooley, Kerry M.; Ross, J.R.H.; Ross, Julian R.H.

    1992-01-01

    A series of potassium/calcium/nickel oxides were tested for the oxidative coupling of methane (OCM) at 843–943 K and water addition to the feed at 0–66 mol-%. The K/Ni ratios varied from 0.0–0.6 and Ca/Ni from 0.0–11; catalysts with no nickel were also tested. At least 10% water in the feed and

  16. Catalyst for Decomposition of Nitrogen Oxides

    Science.gov (United States)

    Schryer, David R. (Inventor); Jordan, Jeffrey D. (Inventor); Akyurtlu, Ates (Inventor); Akyurtlu, Jale (Inventor)

    2015-01-01

    This invention relates generally to a platinized tin oxide-based catalyst. It relates particularly to an improved platinized tin oxide-based catalyst able to decompose nitric oxide to nitrogen and oxygen without the necessity of a reducing gas.

  17. Characterization of TEMPO-oxidized bacterial cellulose

    International Nuclear Information System (INIS)

    Nascimento, Eligenes S.; Pereira, Andre L.S.; Lima, Helder L.; Barroso, Maria K. de A.; Barros, Matheus de O.; Morais, Joao P.S.; Borges, Maria de F.; Rosa, Morsyleide de F.

    2015-01-01

    The aim of this study was to characterize the TEMPO-oxidized bacterial cellulose, as a preliminary research for further application in nanocomposites. Bacterial cellulose (BC) was selectively oxidized at C-6 carbon by TEMPO radical. Oxidized bacterial cellulose (BCOX) was characterized by TGA, FTIR, XRD, and zeta potential. BCOX suspension was stable at pH 7.0, presented a crystallinity index of 83%, in spite of 92% of BC, because of decrease in the free hydroxyl number. FTIR spectra showed characteristic BC bands and, in addition, band of carboxylic group, proving the oxidation. BCOX DTG showed, in addition to characteristic BC thermal events, a maximum degradation peak at 233 °C, related to sodium anhydro-glucuronate groups formed during the cellulose oxidation. Thus, BC can be TEMPO-oxidized without great loss in its structure and properties. (author)

  18. Evolution of zirconium-based precipitates during oxidation and irradiation of Zr alloys (impact on the oxidation kinetics of Zr alloys)

    International Nuclear Information System (INIS)

    Pecheur, Dominique

    1993-01-01

    As the oxidation of the zircaloy sheath is one of the factors which limit the lifetime of nuclear fuel rods, this research thesis aims at a better knowledge of the involved oxidation mechanisms and to improve the oxidation resistance in order to increase rod lifetime. Oxidation test performed in autoclave to study zirconium alloy oxidation without irradiation showed that oxidation kinetics is significantly higher under irradiation. This difference is attributed to a different evolution of the sheath material under irradiation. Thus, this research focused on the role of precipitates in the oxidation process of zirconium alloys, and on the impact of their amorphization on this oxidation. After a detailed description of the context and of the various implemented experimental means, the author presents the results obtained on a reference material on the one hand, and on a material irradiated by ions or neutrons on the other hand. More particularly, the author studied in these both cases the introduction of precipitates in the oxide layer by transmission electronic microscopy, and oxidation kinetics obtained in autoclave on these two types of material. He reports the analysis of the introduction of precipitates in the oxide layer formed on the reference material. He proposes interpretations for the evolutions of structure and of chemical compositions of precipitates in the oxide layer. These observations are then correlated with oxidation kinetics in these alloys. Finally, the author discusses results of oxidation tests obtained on materials irradiated by ions and by neutrons [fr

  19. Radiation induced lipid oxidation in fish

    International Nuclear Information System (INIS)

    Snauwaert, F.; Tobback, P.; Maes, E.; Thyssen, J.

    1977-01-01

    Oxidative rancidity in herring and redfish was studied as a function of the applied irradiation dose, the storage time and storage temperature and the packaging conditions. - Measurements of the TBA (thiobarbituric acid) value and the peroxide value were used to evaluate the degree of oxidation of lipids, and were related with sensory scores. - Especially for the fatty fish species (herring) irradiation accelerated lipid oxidation and induced oxidative rancidity. Irradiation of vacuum-packed herring fillets and subsequent storage at +2 C seems to be an interesting process. For the experiments conducted on a semi-fatty fish (redfish), oxidative rancidity was never the limiting factor for organoleptic acceptability. (orig.) [de

  20. 2,2,2-Trifluoroacetophenone as an organocatalyst for the oxidation of tertiary amines and azines to N-oxides.

    Science.gov (United States)

    Limnios, Dimitris; Kokotos, Christoforos G

    2014-01-07

    A cheap, mild and environmentally friendly oxidation of tertiary amines and azines to the corresponding N-oxides is reported by using polyfluoroalkyl ketones as efficient organocatalysts. 2,2,2-Trifluoroacetophenone was identified as the optimum catalyst for the oxidation of aliphatic tertiary amines and azines. This oxidation is chemoselective and proceeds in high-to-quantitative yields utilizing 10 mol % of the catalyst and H2 O2 as the oxidant. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Periodontitis and increase in circulating oxidative stress

    Directory of Open Access Journals (Sweden)

    Takaaki Tomofuji

    2009-05-01

    Full Text Available Reactive oxygen species (ROS are products of normal cellular metabolism. However, excessive production of ROS oxidizes DNA, lipids and proteins, inducing tissue damage. Studies have shown that periodontitis induces excessive ROS production in periodontal tissue. When periodontitis develops, ROS produced in the periodontal lesion diffuse into the blood stream, resulting in the oxidation of blood molecules (circulating oxidative stress. Such oxidation may be detrimental to systemic health. For instance, previous animal studies suggested that experimental periodontitis induces oxidative damage of the liver and descending aorta by increasing circulating oxidative stress. In addition, it has been revealed that clinical parameters in chronic periodontitis patients showed a significant improvement 2 months after periodontal treatment, which was accompanied by a significant reduction of reactive oxygen metabolites in plasma. Improvement of periodontitis by periodontal treatment could reduce the occurrence of circulating oxidative stress. Furthermore, recent studies indicate that the increase in circulating oxidative stress following diabetes mellitus and inappropriate nutrition damages periodontal tissues. In such cases, therapeutic approaches to systemic oxidative stress might be necessary to improve periodontal health.

  2. Kinetics of abiotic nitrous oxide production via oxidation of hydroxylamine by particulate metals in seawater

    Science.gov (United States)

    Cavazos, A. R.; Taillefert, M.; Glass, J. B.

    2016-12-01

    The oceans are a significant of nitrous oxide (N2O) to the atmosphere. Current models of global oceanic N2­O flux focus on microbial N2O cycling and often ignore abiotic reactions, such as the thermodynamically favorable oxidation of the nitrification intermediate hydroxylamine (NH2OH) by Mn(IV) or Fe(III). At circumneutral pH, NH2OH oxidation is more thermodynamically favorable via Mn(IV) than Fe(III) reduction. We characterized the kinetics of NH2OH oxidation in synthetic ocean water at pH 5.1-8.8 using microsensor electrodes to measure real-time N2O production. N2O production rates and yield were greater when NH2OH was oxidized by Mn(IV) than Fe(III). Accordingly, the reduction of Mn(IV) was first order with respect to NH2OH whereas the reduction of Fe(III) was zero order with respect to NH2OH. Interestingly, the order of the reaction with respect to Mn(IV) appears to be negative whereas the reaction is second order with respect to Fe(III). The inverse order with respect to Mn(IV) may be due to the aggregation of particles in seawater, which decreases their surface area and changes their reactivity. Finally, the reaction is first order with respect to protons with Fe(III) as the oxidant but zero order with Mn(IV). The stronger effect of the pH on the reaction with Fe(III) as the oxidant compared to Mn(IV) reflects the stoichiometry of these two reactions, as each mole of N2O produced by Fe(III) reduction consumes eight protons while each mole of N2O produced with Mn(IV) as the oxidant requires only four protons. Our data show that abiotic NH2OH oxidation by Mn(IV) or Fe(III) particles may represent a significant source of N2O in seawater. These findings suggest that abiotic N2O production in marine waters may be significant in areas of the oceans where particulate metals originating from aerosols, dust, or rivers may react with NH2OH released from ammonia-oxidizing microorganisms.

  3. Graphene oxide and reduced graphene oxide studied by the XRD, TEM and electron spectroscopy methods

    International Nuclear Information System (INIS)

    Stobinski, L.; Lesiak, B.; Malolepszy, A.; Mazurkiewicz, M.; Mierzwa, B.; Zemek, J.; Jiricek, P.; Bieloshapka, I.

    2014-01-01

    Highlights: • Graphene oxide (FL-GOc) and reduced graphene oxide (FL-RGOc): XRD, TEM, XPS, REELS. • FL-GOc: stacking nanostructure—22 × 6 nm (DxH), 0.9 nm layers separation (XRD). • FL-RGOc: stacking nanostructure—8 × 1 nm (DxH), 0.4 nm layers separation (XRD). • Reduction: oxygen group degradation, decreasing distance between graphene layers. • Number of graphene layers in stacking nanostructure: 6–7 (FL-GOc), 2–3 (FL-RGOc). - Abstract: The commercial and synthesised few-layer graphene oxide, prepared using oxidation reactions, and few-layer reduced graphene oxide samples were structurally and chemically investigated by the X-ray diffraction (XRD), transmission electron microscopy (TEM) and electron spectroscopy methods, i.e. X-ray photoelectron spectroscopy (XPS) and reflection electron energy loss spectroscopy (REELS). The commercial graphene oxide (FL-GOc) shows a stacking nanostructure of about 22 × 6 nm average diameter by height with the distance of 0.9 nm between 6-7 graphene layers, whereas the respective reduced graphene oxide (FL-RGOc)—about 8 × 1 nm average diameter by height stacking nanostructure with the distance of 0.4 nm between 2-3 graphene layers (XRD). The REELS results are consistent with those by the XRD indicating 8 (FL-GOc) and 4 layers (FL-RGOc). In graphene oxide and reduced graphene oxide prepared from the graphite the REELS indicates 8–11 and 7–10 layers. All graphene oxide samples show the C/O ratio of 2.1–2.3, 26.5–32.1 at% of C sp 3 bonds and high content of functional oxygen groups (hydroxyl—C-OH, epoxy—C-O-C, carbonyl—C=O, carboxyl—C-OOH, water) (XPS). Reduction increases the C/O ratio to 2.8–10.3, decreases C sp 3 content to 11.4–20.3 at% and also the content of C-O-C and C=O groups, accompanied by increasing content of C-OH and C-OOH groups. Formation of additional amount of water due to functional oxygen group reduction leads to layer delamination. Removing of functional oxygen groups

  4. The oxidative coupling of methane and the oxidative dehydrogenation of ethane over a niobium promoted lithium doped magnesium oxide catalyst

    NARCIS (Netherlands)

    Swaan, H.M.; Swaan, H.M.; Li, X.; Seshan, Kulathuiyer; van Ommen, J.G.; Ross, J.R.H.; Ross, J.R.H.

    1993-01-01

    The promoting effect of niobium in a Li/MgO catalyst for the oxidative coupling of methane (OCM) and for the oxidative dehydrogenation of ethane (ODHE) has been studied in some detail. It has been found that a Li/Nb/MgO catalyst with 16 wt % niobium showed the highest activity for the C2 production

  5. Oxidation of boron carbide at high temperatures

    International Nuclear Information System (INIS)

    Steinbrueck, Martin

    2005-01-01

    The oxidation kinetics of various types of boron carbides (pellets, powder) were investigated in the temperature range between 1073 and 1873 K. Oxidation rates were measured in transient and isothermal tests by means of mass spectrometric gas analysis. Oxidation of boron carbide is controlled by the formation of superficial liquid boron oxide and its loss due to the reaction with surplus steam to volatile boric acids and/or direct evaporation at temperatures above 1770 K. The overall reaction kinetics is paralinear. Linear oxidation kinetics established soon after the initiation of oxidation under the test conditions described in this report. Oxidation is strongly influenced by the thermohydraulic boundary conditions and in particular by the steam partial pressure and flow rate. On the other hand, the microstructure of the B 4 C samples has a limited influence on oxidation. Very low amounts of methane were produced in these tests

  6. Crystalline structure and propylene oxidation in complex bismuth-molybdenum oxide catalysts

    International Nuclear Information System (INIS)

    Manaila, R.; Ionescu, N.I.; Caldararu, M.

    1980-01-01

    Complex Bi-Mo oxide catalysts supported on amorphous SiO 2 were prepared by coprecipitation and tested in the reaction of selective oxidation of propylene to acrolein. They consist of a mixture of molybdate phases and excess MoO 3 . The Fe 2 (MoO 4 ) 3 phase was found to have a high concentration of lattice defects, induced by a Mo excess. These defects could be related to the catalytic conversion and to the selectivity to total oxidation by varying the calcination temperature. Calcination above 500 0 C induced also the transition of the metastable modification β-NiMoO 4 to the stable form α, accompanied by a loss of conversion. A complex Bi molybdate with scheelitic structure was found to have a high selectivity to acrolein. (author)

  7. Constraints on superoxide mediated formation of manganese oxides

    Directory of Open Access Journals (Sweden)

    Deric R. Learman

    2013-09-01

    Full Text Available Manganese (Mn oxides are among the most reactive sorbents and oxidants within the environment, where they play a central role in the cycling of nutrients, metals, and carbon. Recent discoveries have identified superoxide (O2- (both of biogenic and abiogenic origin as an effective oxidant of Mn(II leading to the formation of Mn oxides. Here we examined the conditions under which abiotically produced superoxide led to oxidative precipitation of Mn and the solid-phases produced. Oxidized Mn, as both aqueous Mn(III and Mn(III/IV oxides, was only observed in the presence of active catalase, indicating that hydrogen peroxide, a product of the reaction of O2- with Mn(II, inhibits the oxidation process presumably through the reduction of Mn(III. Citrate and pyrophosphate increased the yield of oxidized Mn but decreased the amount of Mn oxide produced via formation of Mn(III-ligand complexes. While complexing ligands played a role in stabilizing Mn(III, they did not eliminate the inhibition of net Mn(III formation by H2O2. The Mn oxides precipitated were highly disordered colloidal hexagonal birnessite, similar to those produced by biotically generated superoxide. Yet, in contrast to the large particulate Mn oxides formed by biogenic superoxide, abiotic Mn oxides did not ripen to larger, more crystalline phases. This suggests that the deposition of crystalline Mn oxides within the environment requires a biological, or at least organic, influence. This work provides the first direct evidence that, under conditions relevant to natural waters, oxidation of Mn(II by superoxide can occur and lead to formation of Mn oxides. For organisms that oxidize Mn(II by producing superoxide, these findings may also point to other microbially mediated processes, in particular enzymatic hydrogen peroxide degradation and/or production of organic ligand metabolites, that allow for Mn oxide formation.

  8. Two-Step Electrochemical Intercalation and Oxidation of Graphite for the Mass Production of Graphene Oxide.

    Science.gov (United States)

    Cao, Jianyun; He, Pei; Mohammed, Mahdi A; Zhao, Xin; Young, Robert J; Derby, Brian; Kinloch, Ian A; Dryfe, Robert A W

    2017-12-06

    Conventional chemical oxidation routes for the production of graphene oxide (GO), such as the Hummers' method, suffer from environmental and safety issues due to their use of hazardous and explosive chemicals. These issues are addressed by electrochemical oxidation methods, but such approaches typically have a low yield due to inhomogeneous oxidation. Herein we report a two-step electrochemical intercalation and oxidation approach to produce GO on the large laboratory scale (tens of grams) comprising (1) forming a stage 1 graphite intercalation compound (GIC) in concentrated sulfuric acid and (2) oxidizing and exfoliating the stage 1 GIC in an aqueous solution of 0.1 M ammonium sulfate. This two-step approach leads to GO with a high yield (>70 wt %), good quality (>90%, monolayer), and reasonable oxygen content (17.7 at. %). Moreover, the as-produced GO can be subsequently deeply reduced (3.2 at. % oxygen; C/O ratio 30.2) to yield highly conductive (54 600 S m -1 ) reduced GO. Electrochemical capacitors based on the reduced GO showed an ultrahigh rate capability of up to 10 V s -1 due to this high conductivity.

  9. ADVANTAGES/DISADVANTAGES FOR ISCO METHODS IN-SITU FENTON OXIDATION IN-SITU PERMANGANATE OXIDATION

    Science.gov (United States)

    The advantages and disadvantages of in-situ Fenton oxidation and in-situ permanganate oxidation will be presented. This presentation will provide a brief overview of each technology and a detailed analysis of the advantages and disadvantages of each technology. Included in the ...

  10. Kinetics of oxidic phase dissolution in acids

    International Nuclear Information System (INIS)

    Gorichev, I.G.; Kipriyanov, N.A.

    1981-01-01

    The critical analysis of the experimental data on dissolution kinetics of metal oxides (BeO, V 2 O 5 , UO 2 , Nb 2 O 5 , Ta 2 O 5 etc.) in acid media is carried out. Kinetic peculiarities of oxide dissolution are explained on the basis of the notions of electron- proton theory. It is established that the surface nonstoichiometric ccomposition of oxide phase and potential jump, appearing on the interface of the oxide-electrolyte phase are the important factors, determining the dissolution rate of a solid phase. The dissolution rate of metal oxides is limited by the transition of protons into the solid oxide phase. Morphological models of heterogeneous kinetics are used when explaining kinetic regularities of oxide dissolution process [ru

  11. The dynamic of lipid oxidation in human myotubes

    DEFF Research Database (Denmark)

    Gaster, Michael

    2009-01-01

    Both endogenous and exogenous lipid levels may be regulators of total lipid oxidation in skeletal muscles. We studied the dynamics of lipid oxidation in human myotubes established from healthy, lean subjects exposed to acutely and chronically increased palmitate concentrations. The intramyocellular...... triacylglycerol content increased with chronic palmitate exposure. Both, ectopically increased intracellular and extracellular lipid levels were simultaneously oxidized and could partly suppress each other's oxidation. Overall, the highest acute palmitate treatments stimulated fatty acid oxidation whilst...... the highest chronic treatments decreased total lipid oxidation. Intracellular lipids showed a more complete oxidation than exogenous lipids. Endogenous lipids reduced insulin-mediated glucose oxidation. Thus, both endogenous and exogenous lipid concentrations regulated each other's oxidation and total lipid...

  12. Reduction of graphene oxide and its effect on square resistance of reduced graphene oxide films

    Energy Technology Data Exchange (ETDEWEB)

    Hou, Zhaoxia; Zhou, Yin; Li, Guang Bin; Wang, Shaohong; Wang, Mei Han; Hu, Xiaodan; Li, Siming [Liaoning Province Key Laboratory of New Functional Materials and Chemical Technology, School ofMechanical Engineering, Shenyang University, Shenyang (China)

    2015-06-15

    Graphite oxide was prepared via the modified Hummers’ method and graphene via chemical reduction. Deoxygenation efficiency of graphene oxide was compared among single reductants including sodium borohydride, hydrohalic acids, hydrazine hydrate, and vitamin C. Two-step reduction of graphene oxide was primarily studied. The reduced graphene oxide was characterized by XRD, TG, SEM, XPS, and Raman spectroscopy. Square resistance was measured as well. Results showed that films with single-step N2H4 reduction have the best transmittance and electrical conductivity with square resistance of ~5746 Ω/sq at 70% transmittance. This provided an experimental basis of using graphene for electronic device applications.

  13. Amide-N-oxide heterosynthon and amide dimer homosynthon in cocrystals of carboxamide drugs and pyridine N-oxides.

    Science.gov (United States)

    Babu, N Jagadeesh; Reddy, L Sreenivas; Nangia, Ashwini

    2007-01-01

    The carboxamide-pyridine N-oxide heterosynthon is sustained by syn(amide)N-H...O-(oxide) hydrogen bond and auxiliary (N-oxide)C-H...O(amide) interaction (Reddy, L. S.; Babu, N. J.; Nangia, A. Chem. Commun. 2006, 1369). We evaluate the scope and utility of this heterosynthon in amide-containing molecules and drugs (active pharmaceutical ingredients, APIs) with pyridine N-oxide cocrystal former molecules (CCFs). Out of 10 cocrystals in this study and 7 complexes from previous work, amide-N-oxide heterosynthon is present in 12 structures and amide dimer homosynthon occurs in 5 structures. The amide dimer is favored over amide-N-oxide synthon in cocrystals when there is competition from another H-bonding functional group, e.g., 4-hydroxybenzamide, or because of steric factors, as in carbamazepine API. The molecular organization in carbamazepine.quinoxaline N,N'-dioxide 1:1 cocrystal structure is directed by amide homodimer and anti(amide)N-H...O-(oxide) hydrogen bond. Its X-ray crystal structure matches with the third lowest energy frame calculated in Polymorph Predictor (Cerius(2), COMPASS force field). Apart from generating new and diverse supramolecular structures, hydration is controlled in one substance. 4-Picoline N-oxide deliquesces within a day, but its cocrystal with barbital does not absorb moisture at 50% RH and 30 degrees C up to four weeks. Amide-N-oxide heterosynthon has potential utility in both amide and N-oxide type drug molecules with complementary CCFs. Its occurrence probability in the Cambridge Structural Database is 87% among 27 structures without competing acceptors and 78% in 41 structures containing OH, NH, H(2)O functional groups.

  14. Mesoporous metal oxides and processes for preparation thereof

    Energy Technology Data Exchange (ETDEWEB)

    Suib, Steven L.; Poyraz, Altug Suleyman

    2018-03-06

    A process for preparing a mesoporous metal oxide, i.e., transition metal oxide. Lanthanide metal oxide, a post-transition metal oxide and metalloid oxide. The process comprises providing an acidic mixture comprising a metal precursor, an interface modifier, a hydrotropic ion precursor, and a surfactant; and heating the acidic mixture at a temperature and for a period of time sufficient to form the mesoporous metal oxide. A mesoporous metal oxide prepared by the above process. A method of controlling nano-sized wall crystallinity and mesoporosity in mesoporous metal oxides. The method comprises providing an acidic mixture comprising a metal precursor, an interface modifier, a hydrotropic ion precursor, and a surfactant; and heating the acidic mixture at a temperature and for a period of time sufficient to control nano-sized wall crystallinity and mesoporosity in the mesoporous metal oxides. Mesoporous metal oxides and a method of tuning structural properties of mesoporous metal oxides.

  15. Dual passivation of intrinsic defects at the compound semiconductor/oxide interface using an oxidant and a reductant.

    Science.gov (United States)

    Kent, Tyler; Chagarov, Evgeniy; Edmonds, Mary; Droopad, Ravi; Kummel, Andrew C

    2015-05-26

    Studies have shown that metal oxide semiconductor field-effect transistors fabricated utilizing compound semiconductors as the channel are limited in their electrical performance. This is attributed to imperfections at the semiconductor/oxide interface which cause electronic trap states, resulting in inefficient modulation of the Fermi level. The physical origin of these states is still debated mainly because of the difficulty in assigning a particular electronic state to a specific physical defect. To gain insight into the exact source of the electronic trap states, density functional theory was employed to model the intrinsic physical defects on the InGaAs (2 × 4) surface and to model the effective passivation of these defects by utilizing both an oxidant and a reductant to eliminate metallic bonds and dangling-bond-induced strain at the interface. Scanning tunneling microscopy and spectroscopy were employed to experimentally determine the physical and electronic defects and to verify the effectiveness of dual passivation with an oxidant and a reductant. While subsurface chemisorption of oxidants on compound semiconductor substrates can be detrimental, it has been shown theoretically and experimentally that oxidants are critical to removing metallic defects at oxide/compound semiconductor interfaces present in nanoscale channels, oxides, and other nanostructures.

  16. Role of atomic layer deposited aluminum oxide as oxidation barrier for silicon based materials

    Energy Technology Data Exchange (ETDEWEB)

    Fiorentino, Giuseppe, E-mail: g.fiorentino@tudelft.nl; Morana, Bruno [Department of Microelectronic, Delft University of Technology, Feldmannweg 17, 2628 CT Delft (Netherlands); Forte, Salvatore [Department of Electronic, University of Naples Federico II, Piazzale Tecchio, 80125 Napoli (Italy); Sarro, Pasqualina Maria [Department of Microelectronic, Delft University of Technology, Feldmannweg 17, 2628 CT, Delft (Netherlands)

    2015-01-15

    In this paper, the authors study the protective effect against oxidation of a thin layer of atomic layer deposited (ALD) aluminum oxide (Al{sub 2}O{sub 3}). Nitrogen doped silicon carbide (poly-SiC:N) based microheaters coated with ALD Al{sub 2}O{sub 3} are used as test structure to investigate the barrier effect of the alumina layers to oxygen and water vapor at very high temperature (up to 1000 °C). Different device sets have been fabricated changing the doping levels, to evaluate possible interaction between the dopants and the alumina layer. The as-deposited alumina layer morphology has been evaluated by means of AFM analysis and compared to an annealed sample (8 h at 1000 °C) to estimate the change in the grain structure and the film density. The coated microheaters are subjected to very long oxidation time in dry and wet environment (up to 8 h at 900 and 1000 °C). By evaluating the electrical resistance variation between uncoated reference devices and the ALD coated devices, the oxide growth on the SiC is estimated. The results show that the ALD alumina coating completely prevents the oxidation of the SiC up to 900 °C in wet environment, while an oxide thickness reduction of 50% is observed at 1000 °C compared to uncoated devices.

  17. Catalyst for Ammonia Oxidation

    DEFF Research Database (Denmark)

    2015-01-01

    The present invention relates to a bimetallic catalyst for ammonia oxidation, a method for producing a bimetallic catalyst for ammonia oxidation and a method for tuning the catalytic activity of a transition metal. By depositing an overlayer of less catalytic active metal onto a more catalytic...

  18. Whole-body fat oxidation determined by graded exercise and indirect calorimetry: a role for muscle oxidative capacity?

    DEFF Research Database (Denmark)

    Nordby, P; Saltin, B; Helge, J W

    2006-01-01

    During whole-body exercise, peak fat oxidation occurs at a moderate intensity. This study investigated whole-body peak fat oxidation in untrained and trained subjects, and the presence of a relation between skeletal muscle oxidative enzyme activity and whole-body peak fat oxidation. Healthy male...... subjects were recruited and categorized into an untrained (N=8, VO(2max) 3.5+/-0.1 L/min) and a trained (N=8, VO(2max) 4.6+/-0.2 L/min) group. Subjects performed a graded exercise test commencing at 60 W for 8 min followed by 35 W increments every 3 min. On a separate day, muscle biopsies were obtained...... oxidation was determined. The body composition was determined by DEXA. Whole-body peak fat oxidation (250+/-25 and 462+/-33 mg/min) was higher (Ptrained compared with untrained subjects, respectively. Muscle...

  19. Effects of adsorbates on Zircaloy oxidation in air

    International Nuclear Information System (INIS)

    Cho, Y.; Kim, Y-G.; Park, K.

    1997-01-01

    The air-oxidation of Zry and the effects of adsorbates on the oxidation are found by the intermittent measurement of the weight gain of specimens. NaC1 enhances the oxidation, where nonuniform stresses on the surface and C1 ions are the cause. LiOH also enhances the oxidation, where the initial oxide formed by LiOH seems to the reason. The effects of fluorides on oxidation are also measured. NaF is most harmful and KF follows next. LiF does not effect the oxidation of Zry. Diffusion of fluorides in oxide determines the enhancement. (author)

  20. High temperature oxidation kinetics of dysprosium particles

    Energy Technology Data Exchange (ETDEWEB)

    Jaques, Brian J.; Butt, Darryl P., E-mail: DarrylButt@BoiseState.edu

    2015-09-25

    Highlights: • The oxidation behavior of dysprosium particles was studied from 500 to 1000 °C. • Activation energy in initial region found as 8–25 kJ/mol, depending on atmosphere. • Activation energy in intermediate region found as 80–95 kJ/mol. • The oxide grows at the metal–oxide interface. • Generally, the formed oxide behaved as a p-type semiconductor. - Abstract: Rare earth elements have been recognized as critical materials for the advancement of many strategic and green technologies. Recently, the United States Department of Energy has invested many millions of dollars to enhance, protect, and forecast their production and management. The work presented here attempts to clarify the limited and contradictory literature on the oxidation behavior of the rare earth metal, dysprosium. Dysprosium particles were isothermally oxidized from 500 to 1000 °C in N{sub 2}–(2%, 20%, and 50%) O{sub 2} and Ar–20% O{sub 2} using simultaneous thermal analysis techniques. Two distinct oxidation regions were identified at each isothermal temperature in each oxidizing atmosphere. Initially, the oxidation kinetics are very fast until the reaction enters a slower, intermediate region of oxidation. The two regions are defined and the kinetics of each are assessed to show an apparent activation energy of 8–25 kJ/mol in the initial region and 80–95 kJ/mol in the intermediate oxidation reaction region. The effects of varying the oxygen partial pressure on the reaction rate constant are used to show that dysprosium oxide (Dy{sub 2}O{sub 3}) generally acts as a p-type semiconductor in both regions of oxidation (with an exception above 750 °C in the intermediate region)

  1. When do oxide precipitates form during consolidation of oxide dispersion strengthened steels?

    Energy Technology Data Exchange (ETDEWEB)

    Deschamps, A., E-mail: alexis.deschamps@grenoble-inp.fr [Univ. Grenoble Alpes, SIMAP, F-38000 Grenoble (France); CNRS, SIMAP, F-38000 Grenoble (France); De Geuser, F. [Univ. Grenoble Alpes, SIMAP, F-38000 Grenoble (France); CNRS, SIMAP, F-38000 Grenoble (France); Malaplate, J.; Sornin, D. [DEN, DANS, DMN, Service de Recherches Métallurgiques Appliquées, CEA, Université Paris-Saclay, 91191 Gif-Sur-Yvette (France)

    2016-12-15

    The processing of oxide dispersion strengthened (ODS) steels involves ball milling, where the oxide forming species are driven in solid solution. Precipitation of the nanometre-scale oxides occurs during subsequent annealing and consolidation. This paper reports in-situ Small-Angle X-ray Scattering measurements of the formation of these precipitates during heating of cold-compressed as-milled powders. Clusters are already initially present, and precipitation starts at 300 °C. The maximum precipitate density is achieved at 600 °C, followed by very slow coarsening at higher temperature. These results open the way to understand the coupled evolution of precipitation and crystalline defects during heating and consolidation of ODS steels.

  2. Copper oxide as efficient catalyst for oxidative dehydrogenation of alcohols with air

    DEFF Research Database (Denmark)

    Poreddy, Raju; Engelbrekt, Christian; Riisager, Anders

    2015-01-01

    The oxidative dehydrogenation of alcohols to carbonyl compounds was studied using CuO nanoparticle catalysts prepared by solution synthesis in buffered media. CuO nanoparticles synthesized in N-cyclohexyl- 3-aminopropanesulfonic acid buffer showed high catalytic activity for the oxidation...... of benzylic, alicyclic and unsaturated alcohols to their corresponding carbonyl compounds with excellent selectivities. The observed trend in activity for conversion of substituted alcohols suggested a β-H elimination step to be involved, thus enabling a possible reaction mechanism for oxidative...... dehydrogenation of benzyl alcohols to be proposed. The use of CuO as an inexpensive and efficient heterogeneous catalyst under aerobic conditions provides a new noble metal-free and green reaction protocol for carbonyl compound synthesis....

  3. Electron transport properties of indium oxide - indium nitride metal-oxide-semiconductor heterostructures

    International Nuclear Information System (INIS)

    Wang, C.Y.; Hauguth, S.; Polyakov, V.; Schwierz, F.; Cimalla, V.; Kups, T.; Himmerlich, M.; Schaefer, J.A.; Krischok, S.; Ambacher, O.; Morales, F.M.; Lozano, J.G.; Gonzalez, D.; Lebedev, V.

    2008-01-01

    The structural, chemical and electron transport properties of In 2 O 3 /InN heterostructures and oxidized InN epilayers are reported. It is shown that the accumulation of electrons at the InN surface can be manipulated by the formation of a thin surface oxide layer. The epitaxial In 2 O 3 /InN heterojunctions show an increase in the electron concentration due to the increasing band banding at the heterointerface. The oxidation of InN results in improved transport properties and in a reduction of the sheet carrier concentration of the InN epilayer very likely caused by a passivation of surface donors. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  4. Dopamine Oxidation and Autophagy

    Directory of Open Access Journals (Sweden)

    Patricia Muñoz

    2012-01-01

    Full Text Available The molecular mechanisms involved in the neurodegenerative process of Parkinson's disease remain unclear. Currently, there is a general agreement that mitochondrial dysfunction, α-synuclein aggregation, oxidative stress, neuroinflammation, and impaired protein degradation are involved in the neurodegeneration of dopaminergic neurons containing neuromelanin in Parkinson's disease. Aminochrome has been proposed to play an essential role in the degeneration of dopaminergic neurons containing neuromelanin by inducing mitochondrial dysfunction, oxidative stress, the formation of neurotoxic α-synuclein protofibrils, and impaired protein degradation. Here, we discuss the relationship between the oxidation of dopamine to aminochrome, the precursor of neuromelanin, autophagy dysfunction in dopaminergic neurons containing neuromelanin, and the role of dopamine oxidation to aminochrome in autophagy dysfunction in dopaminergic neurons. Aminochrome induces the following: (i the formation of α-synuclein protofibrils that inactivate chaperone-mediated autophagy; (ii the formation of adducts with α- and β-tubulin, which induce the aggregation of the microtubules required for the fusion of autophagy vacuoles and lysosomes.

  5. Diesel soot oxidation under controlled conditions

    OpenAIRE

    Song, Haiwen

    2003-01-01

    This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University, 11/12/2003. In order to improve understanding of diesel soot oxidation, an experimental rig was designed and set up, in which the soot oxidation conditions, such as temperature, oxygen partial pressure, and CO2 partial pressure, could be varied independently of each other. The oxidizing gas flow in the oxidizer was under laminar condition. This test rig comprised a naturally-aspirated single ...

  6. Iron oxide nanoparticle synthesis in aqueous and membrane systems for oxidative degradation of trichloroethylene from water

    Energy Technology Data Exchange (ETDEWEB)

    Gui Minghui; Smuleac, Vasile [University of Kentucky, Department of Chemical and Materials Engineering (United States); Ormsbee, Lindell E. [University of Kentucky, Department of Civil Engineering (United States); Sedlak, David L. [University of California at Berkeley, Department of Civil and Environmental Engineering (United States); Bhattacharyya, Dibakar, E-mail: db@engr.uky.edu [University of Kentucky, Department of Chemical and Materials Engineering (United States)

    2012-05-15

    The potential for using hydroxyl radical (OH{sup Bullet }) reactions catalyzed by iron oxide nanoparticles (NPs) to remediate toxic organic compounds was investigated. Iron oxide NPs were synthesized by controlled oxidation of iron NPs prior to their use for contaminant oxidation (by H{sub 2}O{sub 2} addition) at near-neutral pH values. Cross-linked polyacrylic acid (PAA) functionalized polyvinylidene fluoride (PVDF) microfiltration membranes were prepared by in situ polymerization of acrylic acid inside the membrane pores. Iron and iron oxide NPs (80-100 nm) were directly synthesized in the polymer matrix of PAA/PVDF membranes, which prevented the agglomeration of particles and controlled the particle size. The conversion of iron to iron oxide in aqueous solution with air oxidation was studied based on X-ray diffraction, Moessbauer spectroscopy and BET surface area test methods. Trichloroethylene (TCE) was selected as the model contaminant because of its environmental importance. Degradations of TCE and H{sub 2}O{sub 2} by NP surface generated OH{sup Bullet} were investigated. Depending on the ratio of iron and H{sub 2}O{sub 2}, TCE conversions as high as 100 % (with about 91 % dechlorination) were obtained. TCE dechlorination was also achieved in real groundwater samples with the reactive membranes.

  7. Iron oxide nanoparticle synthesis in aqueous and membrane systems for oxidative degradation of trichloroethylene from water

    International Nuclear Information System (INIS)

    Gui Minghui; Smuleac, Vasile; Ormsbee, Lindell E.; Sedlak, David L.; Bhattacharyya, Dibakar

    2012-01-01

    The potential for using hydroxyl radical (OH • ) reactions catalyzed by iron oxide nanoparticles (NPs) to remediate toxic organic compounds was investigated. Iron oxide NPs were synthesized by controlled oxidation of iron NPs prior to their use for contaminant oxidation (by H 2 O 2 addition) at near-neutral pH values. Cross-linked polyacrylic acid (PAA) functionalized polyvinylidene fluoride (PVDF) microfiltration membranes were prepared by in situ polymerization of acrylic acid inside the membrane pores. Iron and iron oxide NPs (80–100 nm) were directly synthesized in the polymer matrix of PAA/PVDF membranes, which prevented the agglomeration of particles and controlled the particle size. The conversion of iron to iron oxide in aqueous solution with air oxidation was studied based on X-ray diffraction, Mössbauer spectroscopy and BET surface area test methods. Trichloroethylene (TCE) was selected as the model contaminant because of its environmental importance. Degradations of TCE and H 2 O 2 by NP surface generated OH • were investigated. Depending on the ratio of iron and H 2 O 2 , TCE conversions as high as 100 % (with about 91 % dechlorination) were obtained. TCE dechlorination was also achieved in real groundwater samples with the reactive membranes.

  8. Buried oxide layer in silicon

    Science.gov (United States)

    Sadana, Devendra Kumar; Holland, Orin Wayne

    2001-01-01

    A process for forming Silicon-On-Insulator is described incorporating the steps of ion implantation of oxygen into a silicon substrate at elevated temperature, ion implanting oxygen at a temperature below 200.degree. C. at a lower dose to form an amorphous silicon layer, and annealing steps to form a mixture of defective single crystal silicon and polycrystalline silicon or polycrystalline silicon alone and then silicon oxide from the amorphous silicon layer to form a continuous silicon oxide layer below the surface of the silicon substrate to provide an isolated superficial layer of silicon. The invention overcomes the problem of buried isolated islands of silicon oxide forming a discontinuous buried oxide layer.

  9. Clinical Relevance of Biomarkers of Oxidative Stress

    DEFF Research Database (Denmark)

    Frijhoff, Jeroen; Winyard, Paul G; Zarkovic, Neven

    2015-01-01

    SIGNIFICANCE: Oxidative stress is considered to be an important component of various diseases. A vast number of methods have been developed and used in virtually all diseases to measure the extent and nature of oxidative stress, ranging from oxidation of DNA to proteins, lipids, and free amino ac....... The vast diversity in oxidative stress between diseases and conditions has to be taken into account when selecting the most appropriate biomarker.......SIGNIFICANCE: Oxidative stress is considered to be an important component of various diseases. A vast number of methods have been developed and used in virtually all diseases to measure the extent and nature of oxidative stress, ranging from oxidation of DNA to proteins, lipids, and free amino...... acids. RECENT ADVANCES: An increased understanding of the biology behind diseases and redox biology has led to more specific and sensitive tools to measure oxidative stress markers, which are very diverse and sometimes very low in abundance. CRITICAL ISSUES: The literature is very heterogeneous...

  10. La doping effect on TZM alloy oxidation behavior

    International Nuclear Information System (INIS)

    Yang, Fan; Wang, Kuai-She; Hu, Ping; He, Huan-Cheng; Kang, Xuan-Qi; Wang, Hua; Liu, Ren-Zhi; Volinsky, Alex A.

    2014-01-01

    Highlights: • The oxidation can be resisted by doping La into TZM alloy. • La doped TZM alloy has more compact organization. • It can rise the starting temperature of severe oxidation reaction by more than 50 °C. • Effectively slow down the oxidation rate. • Provide guidance for experiments of improving high-temperature oxidation resistance. - Abstract: Powder metallurgy methods were utilized to prepare lanthanum-doped (La-TZM) and traditional TZM alloy plates. High temperature oxidation experiments along with the differential thermal analysis were employed to study the oxidation behavior of the two kinds of TZM alloys. An extremely volatile oxide layer was generated on the surface of traditional TZM alloy plates when the oxidation started. Molybdenum oxide volatilization exposed the alloy matrix, which was gradually corroded by oxygen, losing its quality with serious surface degradation. The La-TZM alloy has a more compact structure due to the lanthanum doping. The minute lanthanum oxide particles are pinned at the grain boundaries and refine the grains. Oxide layer generated on the matrix surface can form a compact coating, which effectively blocks the surface from being corroded by oxidation. The oxidation resistance of La-TZM alloys has been enhanced, expanding its application range

  11. Enhanced performance of solid oxide electrolysis cells by integration with a partial oxidation reactor: Energy and exergy analyses

    International Nuclear Information System (INIS)

    Visitdumrongkul, Nuttawut; Tippawan, Phanicha; Authayanun, Suthida; Assabumrungrat, Suttichai; Arpornwichanop, Amornchai

    2016-01-01

    Highlights: • Process design of solid oxide electrolyzer integrated with a partial oxidation reactor is studied. • Effect of key operating parameters of partial oxidation reactor on the electrolyzer performance is presented. • Exergy analysis of the electrolyzer process is performed. • Partial oxidation reactor can enhance the solid oxide electrolyzer performance. • Partial oxidation reactor in the process is the highest exergy destruction unit. - Abstract: Hydrogen production without carbon dioxide emission has received a large amount of attention recently. A solid oxide electrolysis cell (SOEC) can produce pure hydrogen and oxygen via a steam electrolysis reaction that does not emit greenhouse gases. Due to the high operating temperature of SOEC, an external heat source is required for operation, which also helps to improve SOEC performance and reduce operating electricity. The non-catalytic partial oxidation reaction (POX), which is a highly exothermic reaction, can be used as an external heat source and can be integrated with SOEC. Therefore, the aim of this work is to study the effect of operating parameters of non-catalytic POX (i.e., the oxygen to carbon ratio, operating temperature and pressure) on SOEC performance, including exergy analysis of the process. The study indicates that non-catalytic partial oxidation can enhance the hydrogen production rate and efficiency of the system. In terms of exergy analysis, the non-catalytic partial oxidation reactor is demonstrated to be the highest exergy destruction unit due to irreversible chemical reactions taking place, whereas SOEC is a low exergy destruction unit. This result indicates that the partial oxidation reactor should be improved and optimally designed to obtain a high energy and exergy system efficiency.

  12. Modelling of the partial oxidation of {alpha}, {beta}-unsaturated aldehydes on Mo-V-oxides based catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Boehnke, H.; Petzoldt, J.C.; Stein, B.; Weimer, C.; Gaube, J.W. [Technische Univ. Darmstadt (Germany). Inst. fuer Chemische Technologie

    1998-12-31

    A kinetic model based on the Mars-van Krevelen mechanism that allows to describe the microkinetics of the heterogeneously catalysed partial oxidation of {alpha}, {beta}-unsaturated aldehydes is presented. This conversion is represented by a network, composed of the oxidation of the {alpha}, {beta}-unsaturated aldehyde towards the {alpha}, {beta}-unsaturated carboxylic acid and the consecutive oxidation of the acid as well as the parallel reaction of the aldehyde to products of deeper oxidation. The reaction steps of aldehyde respectively acid oxidation and catalyst reoxidation have been investigated separately in transient experiments. The combination of steady state and transient experiments has led to an improved understanding of the interaction of the catalyst with the aldehyde and the carboxylic acids as well as to a support of the kinetic model assumptions. (orig.)

  13. Oxidation behaviour of Zr-based bulk metallic glasses

    International Nuclear Information System (INIS)

    Wang, Bin

    2011-01-01

    The Zr-based bulk metallic glasses, developed since the late 1980's, have very interesting mechanical properties, which can be considered for many applications including working under oxidizing atmosphere conditions at high temperatures. It is therefore interesting to study their oxidation resistance and to characterize the oxide scale formed on alloys surface. The fundamental objective of this thesis is to enhance the understanding of the role of various thermodynamic and chemistry parameters on the oxidation behaviour of the Zr-based bulk metallic glasses at high temperature under dry air, to determine the residual stresses in the oxide layer, in comparison with their crystalline alloys with the same chemical composition after an annealing treatment. The oxidation kinetics of these glasses and the crystalline structure of oxide scale ZrO 2 depend on the temperature and the oxidation duration: for short periods of oxidation or at a temperature below Tg, the kinetics follows a parabolic law, whereas, if the sample is oxidized at T ≥ Tg, the kinetics can be divided into two parts. The crystalline counterparts are oxidized by a parabolic rule whatever the temperature; for long oxidation duration at a temperature close to Tg, the kinetics becomes more complex because of the crystallisation of the glasses during the oxidation tests. Also the crystalline structure of the oxide layers depends on the oxidation temperature: the oxide layer consists only in tetragonal Zirconia at T ≤ Tg, while monoclinic Zirconia was formed at higher temperature. The mechanism of the formation of the oxide scale is due to both the interior diffusion of Oxygen ions and the external diffusion of Zirconium ions. However the diffusion of Zirconium ions slows gradually during the crystallisation process of the glass matrix. When the crystallisation is completed, the formation of Zirconia is controlled by only the internal diffusion of oxygen ions. The corresponding residual stresses

  14. Enhanced methanol electro-oxidation activity of Pt/MWCNTs electro-catalyst using manganese oxide deposited on MWCNTs

    International Nuclear Information System (INIS)

    Nouralishahi, Amideddin; Khodadadi, Abbas Ali; Mortazavi, Yadollah; Rashidi, Alimorad; Choolaei, Mohammadmehdi

    2014-01-01

    Highlights: • Promoting effects of manganese oxide (MnO x ) on methanol electro-oxidation over Pt/MWCNTs are studied. • 3.3 times higher activity and improved stability are observed on Pt/MnO x -MWCNTs in MOR. • Both hydrogen spill over and bi-functional mechanism are facilitated in presence of MnO x . • MnO x significantly enhances electrochemical active surface area and dispersion of Pt nanoparticles. • Proton conductivity of electrocatalyst layer is improved upon MnO x incorporation. - Abstract: Electro-oxidation of methanol on platinum nanoparticles supported on a nanocomposite of manganese oxide (MnO x ) and multi-wall carbon nanotubes (MWCNTs) is investigated. The morphology, structure, and chemical composition of the electro-catalysts are characterized by TEM, XRD, EDS, TGA, and H 2 -TPR. The electro-catalytic properties of electrodes are examined by cyclic voltammetry, CO-stripping, electrochemical impedance spectroscopy (EIS), and linear sweep voltammetry (LSV). Compared to Pt/MWCNTs, the Pt/MnO x -MWCNTs electro-catalyst exhibits about 3.3 times higher forward peak current density, during cyclic voltammetry, and 4.6 times higher exchange current density in methanol electro-oxidation reaction. In addition, deposition of manganese oxide onto MWCNTs dramatically increases the electrochemical active surface area from 29.7 for Pt/MWCNTs to 89.4 m 2 g −1 Pt for Pt/MnO x -MWCNTs. The results of long-term cyclic voltammetry show superior stability of Pt nanoparticles upon addition of manganese oxide to the support. Furthermore, the kinetics of formation of the chemisorbed OH groups improves upon manganese oxide incorporation. This leads to a lower onset potential of CO ads oxidation on Pt/MnO x -MWCNTs than on Pt/MWCNTs

  15. The influence of deformation, annealing and recrystallisation on oxide nanofeatures in oxide dispersion strengthened steel

    Energy Technology Data Exchange (ETDEWEB)

    Dawson, Karl, E-mail: k.dawson@liverpool.ac.uk; Tatlock, Gordon J.

    2017-04-01

    This work demonstrates that Y-Ti oxide nanofeatures, observed in as-extruded oxide dispersion strengthened steel, are structurally modified by cold forging. A 950 °C heat treatment promoted restructuring of the deformed particles and partial recrystallisation of the cold forged alloy. Transmission electron microscopy revealed that cuboid shaped nanofeatures were deformed during forging, which resulted in high number densities of lens shaped yttrium-titanium oxide particles. Annealing the forged alloy promoted partial recrystallisation of the ferritic matrix. Particle morphology reverted from lens shaped, as witnessed in the deformed material, to cuboid shaped oxide nanofeatures, identical to those observed in as-extruded material. Precipitation distributions evaluated in both recrystallised and recovering grains were indistinguishable from those first measured in the as-extruded alloy. TEM images revealed a widespread orientation relationship between the oxide precipitates and the recrystallised grains; registration with the ferrite lattice was omnipresent in both recovering and recrystallised grains.

  16. Oxidation in fish oil enriched mayonnaise : Ascorbic acid and low pH increase oxidative deterioration

    DEFF Research Database (Denmark)

    Jacobsen, Charlotte; Timm Heinrich, Maike; Meyer, Anne S.

    2001-01-01

    The effect of ascorbic acid (0-4000 ppm) and pH (3.8-6.2) on oxidation and levels of iron and copper in various fractions of mayonnaise enriched with 16% fish oil was investigated. Ascorbic acid induced release of iron from the assumed oil- water interface into the aqueous phase at all pH levels......, but this effect of ascorbic acid was strongest at low pH (pH 3.8- 4.2). Ascorbic acid generally promoted formation of volatile oxidation compounds and reduced the peroxide value in mayonnaises. Peroxide values and total volatiles generally increased with decreasing pH values, suggesting that low pH promoted...... oxidation. It is proposed that iron bridges between the egg yolk proteins low-density lipoproteins, lipovitellin, and phosvitin at the oil-water interface are broken at low pH values, whereby iron ions become accessible as oxidation initiators. In the presence of ascorbic acid, oxidation is further enhanced...

  17. Three manganese oxide-rich marine sediments harbor similar communities of acetate-oxidizing manganese-reducing bacteria

    OpenAIRE

    Vandieken, Verona; Pester, Michael; Finke, Niko; Hyun, Jung-Ho; Friedrich, Michael W; Loy, Alexander; Thamdrup, Bo

    2012-01-01

    Dissimilatory manganese reduction dominates anaerobic carbon oxidation in marine sediments with high manganese oxide concentrations, but the microorganisms responsible for this process are largely unknown. In this study, the acetate-utilizing manganese-reducing microbiota in geographically well-separated, manganese oxide-rich sediments from Gullmar Fjord (Sweden), Skagerrak (Norway) and Ulleung Basin (Korea) were analyzed by 16S rRNA-stable isotope probing (SIP). Manganese reduction was the p...

  18. Amperometric detection and electrochemical oxidation of aliphatic amines and ammonia on silver-lead oxide thin-film electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Ge, Jisheng [Iowa State Univ., Ames, IA (United States)

    1996-01-08

    This thesis comprises three parts: Electrocatalysis of anodic oxygen-transfer reactions: aliphatic amines at mixed Ag-Pb oxide thin-film electrodes; oxidation of ammonia at anodized Ag-Pb eutectic alloy electrodes; and temperature effects on oxidation of ethylamine, alanine, and aquated ammonia.

  19. Oxide nanoparticles in an Al-alloyed oxide dispersion strengthened steel: crystallographic structure and interface with ferrite matrix

    DEFF Research Database (Denmark)

    Zhang, Zhenbo; Pantleon, Wolfgang

    2017-01-01

    Oxide nanoparticles are quintessential for ensuring the extraordinary properties of oxide dispersion strengthened (ODS) steels. In this study, the crystallographic structure of oxide nanoparticles, and their interface with the ferritic steel matrix in an Al-alloyed ODS steel, i.e. PM2000, were...

  20. ADVANCED OXIDATION PROCESSES (AOX) TEXTILE WASTEWATER

    OpenAIRE

    Salas C., G.

    2014-01-01

    Advanced Oxidation Processes (AOX) are based on the in situ generation of hydroxyradicals (·OH), which have a high oxidation potential. In the case of Fenton processes !he generation of hydroxy radicals takes place by the combination of an oxidation agent (H202) with a catalyst (Fe(II)). These radicals are not selective and they react very fast with the organic matter,being able to oxidize a high variety of organic compounds. This property allows the degradation of pollutants into more biodeg...