Highly oxidized graphene oxide and methods for production thereof

DOEpatents

Tour, James M.; Kosynkin, Dmitry V.

2016-08-30

A highly oxidized form of graphene oxide and methods for production thereof are described in various embodiments of the present disclosure. In general, the methods include mixing a graphite source with a solution containing at least one oxidant and at least one protecting agent and then oxidizing the graphite source with the at least one oxidant in the presence of the at least one protecting agent to form the graphene oxide. Graphene oxide synthesized by the presently described methods is of a high structural quality that is more oxidized and maintains a higher proportion of aromatic rings and aromatic domains than does graphene oxide prepared in the absence of at least one protecting agent. Methods for reduction of graphene oxide into chemically converted graphene are also disclosed herein. The chemically converted graphene of the present disclosure is significantly more electrically conductive than is chemically converted graphene prepared from other sources of graphene oxide.

Volatile organometallic complexes suitable for use in chemical vapor depositions on metal oxide films

DOEpatents

Giolando, Dean M.

2003-09-30

Novel ligated compounds of tin, titanium, and zinc are useful as metal oxide CVD precursor compounds without the detriments of extreme reactivity yet maintaining the ability to produce high quality metal oxide coating by contact with heated substrates.

Transparent conducting oxides and production thereof

DOEpatents

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

2014-05-27

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 (110) doped with either a high-permittivity oxide or a low-permittivity oxide in a process chamber (100). The method may also comprise depositing a metal oxide on the target (110) to form a thin film having enhanced optical properties without substantially decreasing electrical quality.

Transparent conducting oxides and production thereof

DOEpatents

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.

Diverse manganese(II)-oxidizing bacteria are prevalent in drinking water systems.

PubMed

Marcus, Daniel N; Pinto, Ameet; Anantharaman, Karthik; Ruberg, Steven A; Kramer, Eva L; Raskin, Lutgarde; Dick, Gregory J

2017-04-01

Manganese (Mn) oxides are highly reactive minerals that influence the speciation, mobility, bioavailability and toxicity of a wide variety of organic and inorganic compounds. Although Mn(II)-oxidizing bacteria are known to catalyze the formation of Mn oxides, little is known about the organisms responsible for Mn oxidation in situ, especially in engineered environments. Mn(II)-oxidizing bacteria are important in drinking water systems, including in biofiltration and water distribution systems. Here, we used cultivation dependent and independent approaches to investigate Mn(II)-oxidizing bacteria in drinking water sources, a treatment plant and associated distribution system. We isolated 29 strains of Mn(II)-oxidizing bacteria and found that highly similar 16S rRNA gene sequences were present in all culture-independent datasets and dominant in the studied drinking water treatment plant. These results highlight a potentially important role for Mn(II)-oxidizing bacteria in drinking water systems, where biogenic Mn oxides may affect water quality in terms of aesthetic appearance, speciation of metals and oxidation of organic and inorganic compounds. Deciphering the ecology of these organisms and the factors that regulate their Mn(II)-oxidizing activity could yield important insights into how microbial communities influence the quality of drinking water. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.

Preparation of highly conductive, transparent, and flexible graphene/silver nanowires substrates using non-thermal laser photoreduction

NASA Astrophysics Data System (ADS)

Anis, Badawi; Mostafa, A. M.; El Sayed, Z. A.; Khalil, A. S. G.; Abouelsayed, A.

2018-07-01

We present the preparation of highly conducting, transparent, and flexible reduced graphene oxide/silver nanowires (rGO/SNWs) substrates using non-thermal laser photoreduction method. High quality monolayers graphene oxide (GO) solution has been prepared by the chemical oxidation of thermally expanded large area natural graphite. Silver nanowires was prepared by using the typical polyol method. Uniform hybrid GO/silver nanowires (GO/SNWs) was prepared by growing the nanowires from silver nuclei in the presence of GO. Uniform and high-quality rGO/SNWs thin films were prepared using a dip-coating technique and were reduced to highly electrically conductive graphene and transparent conductive films using non-thermal laser scribe method. The laser scribed rGO/SNWs hybrid film exhibited 80% transparency with 70 Ω □-1 after 20 min of dipping in GO/SNWs solution.

Fat Quality Influences the Obesogenic Effect of High Fat Diets

PubMed Central

Crescenzo, Raffaella; Bianco, Francesca; Mazzoli, Arianna; Giacco, Antonia; Cancelliere, Rosa; di Fabio, Giovanni; Zarrelli, Armando; Liverini, Giovanna; Iossa, Susanna

2015-01-01

High fat and/or carbohydrate intake are associated with an elevated risk for obesity and chronic diseases such as diabetes and cardiovascular diseases. The harmful effects of a high fat diet could be different, depending on dietary fat quality. In fact, high fat diets rich in unsaturated fatty acids are considered less deleterious for human health than those rich in saturated fat. In our previous studies, we have shown that rats fed a high fat diet developed obesity and exhibited a decrease in oxidative capacity and an increase in oxidative stress in liver mitochondria. To investigate whether polyunsaturated fats could attenuate the above deleterious effects of high fat diets, energy balance and body composition were assessed after two weeks in rats fed isocaloric amounts of a high-fat diet (58.2% by energy) rich either in lard or safflower/linseed oil. Hepatic functionality, plasma parameters, and oxidative status were also measured. The results show that feeding on safflower/linseed oil diet attenuates the obesogenic effect of high fat diets and ameliorates the blood lipid profile. Conversely, hepatic steatosis and mitochondrial oxidative stress appear to be negatively affected by a diet rich in unsaturated fatty acids. PMID:26580650

Fat Quality Influences the Obesogenic Effect of High Fat Diets.

PubMed

Crescenzo, Raffaella; Bianco, Francesca; Mazzoli, Arianna; Giacco, Antonia; Cancelliere, Rosa; di Fabio, Giovanni; Zarrelli, Armando; Liverini, Giovanna; Iossa, Susanna

2015-11-16

High fat and/or carbohydrate intake are associated with an elevated risk for obesity and chronic diseases such as diabetes and cardiovascular diseases. The harmful effects of a high fat diet could be different, depending on dietary fat quality. In fact, high fat diets rich in unsaturated fatty acids are considered less deleterious for human health than those rich in saturated fat. In our previous studies, we have shown that rats fed a high fat diet developed obesity and exhibited a decrease in oxidative capacity and an increase in oxidative stress in liver mitochondria. To investigate whether polyunsaturated fats could attenuate the above deleterious effects of high fat diets, energy balance and body composition were assessed after two weeks in rats fed isocaloric amounts of a high-fat diet (58.2% by energy) rich either in lard or safflower/linseed oil. Hepatic functionality, plasma parameters, and oxidative status were also measured. The results show that feeding on safflower/linseed oil diet attenuates the obesogenic effect of high fat diets and ameliorates the blood lipid profile. Conversely, hepatic steatosis and mitochondrial oxidative stress appear to be negatively affected by a diet rich in unsaturated fatty acids.

Electrolytic exfoliation of graphite in water with multifunctional electrolytes: en route towards high quality, oxide-free graphene flakes.

PubMed

Munuera, J M; Paredes, J I; Villar-Rodil, S; Ayán-Varela, M; Martínez-Alonso, A; Tascón, J M D

2016-02-07

Electrolytic--usually referred to as electrochemical--exfoliation of graphite in water under anodic potential holds enormous promise as a simple, green and high-yield method for the mass production of graphene, but currently suffers from several drawbacks that hinder its widespread adoption, one of the most critical being the oxidation and subsequent structural degradation of the carbon lattice that is usually associated with such a production process. To overcome this and other limitations, we introduce and implement the concept of multifunctional electrolytes. The latter are amphiphilic anions (mostly polyaromatic hydrocarbons appended with sulfonate groups) that play different relevant roles as (1) an intercalating electrolyte to trigger exfoliation of graphite into graphene flakes, (2) a dispersant to afford stable aqueous colloidal suspensions of the flakes suitable for further use, (3) a sacrificial agent to prevent graphene oxidation during exfoliation and (4) a linker to promote nanoparticle anchoring on the graphene flakes, yielding functional hybrids. The implementation of this strategy with some selected amphiphiles even furnishes anodically exfoliated graphenes of a quality similar to that of flakes produced by direct, ultrasound- or shear-induced exfoliation of graphite in the liquid phase (i.e., almost oxide- and defect-free). These high quality materials were used for the preparation of catalytically efficient graphene-Pt nanoparticle hybrids, as demonstrated by model reactions (reduction of nitroarenes). The multifunctional performance of these electrolytes is also discussed and rationalized, and a mechanistic picture of their oxidation-preventing ability is proposed. Overall, the present results open the prospect of anodic exfoliation as a competitive method for the production of very high quality graphene flakes.

Gas-assisted electron-beam-induced nanopatterning of high-quality titanium oxide.

PubMed

Riazanova, A V; Costanzi, B N; Aristov, A I; Rikers, Y G M; Mulders, J J L; Kabashin, A V; Dahlberg, E Dan; Belova, L M

2016-03-18

Electron-beam-induced deposition of titanium oxide nanopatterns is described. The precursor is titanium tetra-isopropoxide, delivered to the deposition point through a needle and mixed with oxygen at the same point via a flow through a separate needle. The depositions are free of residual carbon and have an EDX determined stoichiometry of TiO2.2. High resolution transmission electron microscopy and Raman spectroscopy studies reveal an amorphous structure of the fabricated titanium oxide. Ellipsometric characterization of the deposited material reveals a refractive index of 2.2-2.4 RIU in the spectral range of 500-1700 nm and a very low extinction coefficient (lower than 10(-6) in the range of 400-1700 nm), which is consistent with high quality titanium oxide. The electrical resistivity of the titanium oxide patterned with this new process is in the range of 10-40 GΩ cm and the measured breakdown field is in the range of 10-70 V μm(-1). The fabricated nanopatterns are important for a variety of applications, including field-effect transistors, memory devices, MEMS, waveguide structures, bio- and chemical sensors.

Gas-assisted electron-beam-induced nanopatterning of high-quality titanium oxide

NASA Astrophysics Data System (ADS)

Riazanova, A. V.; Costanzi, B. N.; Aristov, A. I.; Rikers, Y. G. M.; Mulders, J. J. L.; Kabashin, A. V.; Dahlberg, E. Dan; Belova, L. M.

2016-03-01

Electron-beam-induced deposition of titanium oxide nanopatterns is described. The precursor is titanium tetra-isopropoxide, delivered to the deposition point through a needle and mixed with oxygen at the same point via a flow through a separate needle. The depositions are free of residual carbon and have an EDX determined stoichiometry of TiO2.2. High resolution transmission electron microscopy and Raman spectroscopy studies reveal an amorphous structure of the fabricated titanium oxide. Ellipsometric characterization of the deposited material reveals a refractive index of 2.2-2.4 RIU in the spectral range of 500-1700 nm and a very low extinction coefficient (lower than 10-6 in the range of 400-1700 nm), which is consistent with high quality titanium oxide. The electrical resistivity of the titanium oxide patterned with this new process is in the range of 10-40 GΩ cm and the measured breakdown field is in the range of 10-70 V μm-1. The fabricated nanopatterns are important for a variety of applications, including field-effect transistors, memory devices, MEMS, waveguide structures, bio- and chemical sensors.

Changes in Acylglycerols composition, quality characteristics and in vivo effects of dietary pumpkin seed oil upon thermal oxidation

NASA Astrophysics Data System (ADS)

Zeb, Alam; Ahmad, Sultan

2017-07-01

This study was aimed to determine the acylglycerols composition, quality characteristics and protective role of dietary pumpkin seed oil in rabbits. Pumpkin seed oil was thermally oxidized and analyzed for quality characteristics and acylglycerols composition using reversed phase high performance liquid chromatography with diode array detection (HPLC-DAD). Oxidized and un-oxidized oil samples were fed to the rabbits in different doses for two weeks. The changes in the serum biochemistry, hematology, and liver histology were studied. The levels of quality parameters such peroxide value (PV), anisidine value (AV), total phenolic contents (TPC), thiobarbituric acid reactive substances (TBARS), conjugated dienes (CD) and conjugated trienes (CT) significantly increased with thermal treatment. HPLC analyses revealed ten individual triacylglycerols (TAGs), total di-acylglycerols (DAGs), mono-acylglycerols (MAGs), and total oxidized TAGs. Trilinolein (LLL), 1-oleoyl-2,3-dilinolinoyl glycerol (OLL), triolein (OOO) and 1,2-distearoyl-3-palmitoyl glycerol (SSP) were present in higher amounts and decreased with thermal treatment. Animal's studies showed that oxidized oils decreased the whole body weight, which was ameliorated by the co-administration of un-oxidized oils. The levels of serum biochemical parameters were improved by co-administration of pumpkin seed oils. There were no significant effects of both oxidized and un-oxidized pumpkin seed oil on the hematological and histological parameters of rabbits. In conclusion, nutritionally important triacylglycerols were present in pumpkin seed oil with protective role against the toxicity of its corresponding oxidized oils.

High quality transparent conducting oxide thin films

DOEpatents

Gessert, Timothy A.; Duenow, Joel N.; Barnes, Teresa; Coutts, Timothy J.

2012-08-28

A transparent conducting oxide (TCO) film comprising: a TCO layer, and dopants selected from the elements consisting of Vanadium, Molybdenum, Tantalum, Niobium, Antimony, Titanium, Zirconium, and Hafnium, wherein the elements are n-type dopants; and wherein the transparent conducting oxide is characterized by an improved electron mobility of about 42 cm.sup.2/V-sec while simultaneously maintaining a high carrier density of .about.4.4e.times.10.sup.20 cm.sup.-3.

Unusually high soil nitrogen oxide emissions influence air quality in a high-temperature agricultural region

PubMed Central

Oikawa, P. Y.; Ge, C.; Wang, J.; Eberwein, J. R.; Liang, L. L.; Allsman, L. A.; Grantz, D. A.; Jenerette, G. D.

2015-01-01

Fertilized soils have large potential for production of soil nitrogen oxide (NOx=NO+NO2), however these emissions are difficult to predict in high-temperature environments. Understanding these emissions may improve air quality modelling as NOx contributes to formation of tropospheric ozone (O3), a powerful air pollutant. Here we identify the environmental and management factors that regulate soil NOx emissions in a high-temperature agricultural region of California. We also investigate whether soil NOx emissions are capable of influencing regional air quality. We report some of the highest soil NOx emissions ever observed. Emissions vary nonlinearly with fertilization, temperature and soil moisture. We find that a regional air chemistry model often underestimates soil NOx emissions and NOx at the surface and in the troposphere. Adjusting the model to match NOx observations leads to elevated tropospheric O3. Our results suggest management can greatly reduce soil NOx emissions, thereby improving air quality. PMID:26556236

Avoiding polar catastrophe in the growth of polarly orientated nickel perovskite thin films by reactive oxide molecular beam epitaxy

NASA Astrophysics Data System (ADS)

Yang, H. F.; Liu, Z. T.; Fan, C. C.; Yao, Q.; Xiang, P.; Zhang, K. L.; Li, M. Y.; Liu, J. S.; Shen, D. W.

2016-08-01

By means of the state-of-the-art reactive oxide molecular beam epitaxy, we synthesized (001)- and (111)-orientated polar LaNiO3 thin films. In order to avoid the interfacial reconstructions induced by polar catastrophe, screening metallic Nb-doped SrTiO3 and iso-polarity LaAlO3 substrates were chosen to achieve high-quality (001)-orientated films in a layer-by-layer growth mode. For largely polar (111)-orientated films, we showed that iso-polarity LaAlO3 (111) substrate was more suitable than Nb-doped SrTiO3. In situ reflection high-energy electron diffraction, ex situ high-resolution X-ray diffraction, and atomic force microscopy were used to characterize these films. Our results show that special attentions need to be paid to grow high-quality oxide films with polar orientations, which can prompt the explorations of all-oxide electronics and artificial interfacial engineering to pursue intriguing emergent physics like proposed interfacial superconductivity and topological phases in LaNiO3 based superlattices.

Intramuscular variations of proteome and muscle fiber type distribution in semimembranosus and semitendinosus muscles associated with pork quality.

PubMed

Kim, Gap-Don; Yang, Han-Sul; Jeong, Jin-Yeon

2018-04-01

Proteome analysis was performed to understand intramuscular variations in muscle fiber distribution in semimembranosus (SM) and semitendinosus (ST) muscles associated with pork quality. Fifteen SM and ST muscles were separated into dark and light portions. The relative area of oxidative fiber was higher (P < .0001) in dark portion than that in light portion, while glycolytic fiber types were distributed primarily (P < .01) in light portions regardless of muscle types. Myosin-1, myosin-4, troponin complex (fast), myosin light chains, and metabolic enzymes responsible for fast-twitch glycolytic types were overexpressed in light portions (P < .05). However, myosin-2, myosin-7, myoglobin, and mitochondrial oxidative metabolic enzymes were closely related to slow-twitch oxidative fibers. These resulted in high pH, redness, and tenderness but low lightness and drip loss of pork quality. In conclusion, differentially expressed muscle proteins are associated with fiber type (oxidative vs. glycolytic) distribution, resulting in intramuscular variations of pork quality. Copyright © 2017 Elsevier Ltd. All rights reserved.

Polymer-assisted aqueous deposition of metal oxide films

DOEpatents

Li, DeQuan [Los Alamos, NM; Jia, Quanxi [Los Alamos, NM

2003-07-08

An organic solvent-free process for deposition of metal oxide thin films is presented. The process includes aqueous solutions of necessary metal precursors and an aqueous solution of a water-soluble polymer. After a coating operation, the resultant coating is fired at high temperatures to yield optical quality metal oxide thin films.

Method for producing high quality oxide films on substrates

DOEpatents

Ruckman, Mark W.; Strongin, Myron; Gao, Yong L.

1993-01-01

A method for providing an oxide film of a material on the surface of a substrate using a reactive deposition of the material onto the substrate surface in the presence of a solid or liquid layer of an oxidizing gas. The oxidizing gas is provided on the substrate surface in an amount sufficient to dissipate the latent heat of condensation occurring during deposition as well as creating a favorable oxidizing environment for the material.

High quality oxide films on substrates

DOEpatents

Ruckman, Mark W.; Strongin, Myron; Gao, Yong L.

1994-01-01

A method for providing an oxide film of a material on the surface of a substrate using a reactive deposition of the material onto the substrate surface in the presence of a solid or liquid layer of an oxidizing gas. The oxidizing gas is provided on the substrate surface in an amount sufficient to dissipate the latent heat of condensation occurring during deposition as well as creating a favorable oxidizing environment for the material.

Development of a radiation-hard CMOS process

NASA Technical Reports Server (NTRS)

Power, W. L.

1983-01-01

It is recommended that various techniques be investigated which appear to have the potential for improving the radiation hardness of CMOS devices for prolonged space flight mission. The three key recommended processing techniques are: (1) making the gate oxide thin. It has been shown that radiation degradation is proportional to the cube of oxide thickness so that a relatively small reduction in thickness can greatly improve radiation resistance; (2) cleanliness and contamination control; and (3) to investigate different oxide growth (low temperature dry, TCE and HCL). All three produce high quality clean oxides, which are more radiation tolerant. Technique 2 addresses the reduction of metallic contamination. Technique 3 will produce a higher quality oxide by using slow growth rate conditions, and will minimize the effects of any residual sodium contamination through the introduction of hydrogen and chlorine into the oxide during growth.

Growth performance, carcass trait, meat quality and oxidative stability of beef cattle offered alternative silages in a finishing ration.

PubMed

He, L; Yang, J; Chen, W; Zhou, Z; Wu, H; Meng, Q

2018-03-01

As lack of forage resource, alternative roughage sources have been developed for ruminant production and their inclusion would exert a great effect on the dietary nutrition, consequently affecting animal performance. Four silages (corn silage (CS), corn stalk silage (SS), inoculated CS and inoculated SS) were separately offered to 60 Bohai Black cattle (15 cattle/group) during a 24-week finishing period, in which the growth performance, carcass trait, beef quality and oxidative stability of steers were determined. Neither silage material nor silage inoculant exerted a significant effect on the growth performance, carcass trait and oxidative stability of beef cattle (P>0.05). As to beef quality, cattle offered CS had higher (P0.05) on the proximate components and fatty acids profile of beef muscle. There was neither an interaction (P>0.05) between inoculated treatment and silage material. There were no differences (P>0.05) in cholesterol content and meat quality traits in animals fed alternative silages. The collective findings suggest that it is not economical to substitute high-quality forage for relative low-quality forage in a high-concentrate finishing ration of beef cattle and silage inoculant inclusion would not exert a direct effect on animal performance.

Influence of chestnut tannins on welfare, carcass characteristics, meat quality, and lipid oxidation in rabbits under high ambient temperature.

PubMed

Liu, Huawei; Zhou, Daowei; Tong, Jianming; Vaddella, Venkata

2012-01-01

A study was conducted to evaluate the influence of chestnut tannins (CT) on welfare, carcass characteristics, meat quality, and lipid oxidation in rabbits under high ambient temperature. Rabbits in one group were raised at 20°C and fed with basal diet (N) and other three groups (33°C) were fed basal diet with 0 (C), 5 (CT5), and 10 g (CT10) of CT/kg of diet. Compared with the C group, rabbits in CT10 had higher pH(24) and lower cooking loss and thiobarbituric acid reacting substance values at 0, 30, and 60 min of forced oxidation. Rabbits in C group had higher cortisol levels, creatine kinase activities, white blood cell counts, neutrophil percentage, neutrophil:lymphocyte ratio and lower T(3), T(4) levels, lymphocyte percentage than N and CT10 groups. Supplementation of CT seemed to have a positive effect on growth performance, welfare, and meat quality of rabbits under high ambient temperature. Copyright © 2011 Elsevier Ltd. All rights reserved.

Jussara berry (Euterpe edulis M.) oil-in-water emulsions are highly stable: the role of natural antioxidants in the fruit oil.

PubMed

Carvalho, Aline G A; Silva, Kelly A; Silva, Laís O; Costa, André M M; Akil, Emília; Coelho, Maria A Z; Torres, Alexandre G

2018-05-23

Antioxidants help prevent lipid oxidation, and therefore are critical to maintain sensory quality and chemical characteristics of edible oils. Jussara berry (Euterpe edulis M.) oil is a source of minor compounds with potential antioxidant activity. The aim of this work was to investigate the role of such compounds on the effectiveness to prevent or delay oxidation of oil present in oil-in-water emulsions, and how the emulsions physical stability would be affected. Jussara berry oil extracted by ethanol extraction, its stripped variations (partially stripped, highly stripped and highly stripped with added BHT), and expeller pressed oil were used to prepare oil-in-water emulsions. Jussara berry oils were analyzed before emulsions preparation to ensure its initial quality and composition, and oil-in-water emulsions were analyzed regarding their oxidative and physical stability. Ethanol extracted oil emulsion presented higher oxidative stability when compared to highly stripped oil emulsion with added synthetic antioxidant BHT (oxidative stability index 45% lower, after 60 days, and reached undetectable levels after 90 days). All emulsions maintained physically stable for up to 120 days of storage. Our results indicate that natural antioxidants in jussara berry oil protect emulsions from oxidation while keeping physical stability unchanged. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Dietary antioxidant supplementation enhances lipid and protein oxidative stability of chicken broiler meat through promotion of antioxidant enzyme activity1

PubMed Central

Delles, Rebecca M.; Xiong, Youling L.; True, Alma D.; Ao, Touying; Dawson, Karl A.

2014-01-01

Recent nutrigenomic studies have shown that animal nutrition can have a major influence on tissue gene expression. Dietary antioxidant supplements can enhance the quality of meat through modification of tissue metabolic processes. This study investigated the influence of dietary antioxidants and quality of oil on the oxidative and enzymatic properties of chicken broiler breast meat stored in an oxygen-enriched package (HiOx: 80% O2/20% CO2) in comparison with air-permeable polyvinylchloride (PVC) or skin packaging systems during retail display at 2 to 4°C for up to 21 d. Broilers were fed either a diet with a low-oxidized (peroxide value 23 mEq of O2/kg) or high-oxidized (peroxide value 121 mEq of O2/kg) oil, supplemented with or without an algae-based Se yeast and organic mineral antioxidant pack for 42 d. Lipid and protein oxidation and tissue enzymatic activity were analyzed. In all packaging systems, lipid oxidation (TBA reactive substances) was inhibited by up to 32.5% (P < 0.05) with an antioxidant-supplemented diet when compared with diets without antioxidants, particularly in the HiOx and PVC systems. Protein sulfhydryls were significantly protected by antioxidant diets (e.g., by 14.6 and 17.8% for low-and high-oxidized dietary groups, respectively, in PVC d 7 samples). Glutathione peroxidase, catalase, and superoxide dismutase activities were significantly higher (P < 0.05) in antioxidant-supplemented diets compared with the basal diet, regardless of oil quality. Also, serum carbonyls were lower in broilers fed a low-oxidized antioxidant-supplemented treatment. The results demonstrate that dietary antioxidants can minimize the oxidative instability of proteins and lipids, and the protection may be linked to improved cellular antioxidant enzymatic activity. PMID:24879706

High quality oxide films on substrates

DOEpatents

Ruckman, M.W.; Strongin, M.; Gao, Y.L.

1994-02-01

A method is described for providing an oxide film of a material on the surface of a substrate using a reactive deposition of the material onto the substrate surface in the presence of a solid or liquid layer of an oxidizing gas. The oxidizing gas is provided on the substrate surface in an amount sufficient to dissipate the latent heat of condensation occurring during deposition as well as creating a favorable oxidizing environment for the material. 4 figures.

Method for producing high quality oxide films on substrates

DOEpatents

Ruckman, M.W.; Strongin, M.; Gao, Y.L.

1993-11-23

A method is described for providing an oxide film of a material on the surface of a substrate using a reactive deposition of the material onto the substrate surface in the presence of a solid or liquid layer of an oxidizing gas. The oxidizing gas is provided on the substrate surface in an amount sufficient to dissipate the latent heat of condensation occurring during deposition as well as creating a favorable oxidizing environment for the material. 4 figures.

Development of multi-pixel x-ray source using oxide-coated cathodes.

PubMed

Kandlakunta, Praneeth; Pham, Richard; Khan, Rao; Zhang, Tiezhi

2017-07-07

Multiple pixel x-ray sources facilitate new designs of imaging modalities that may result in faster imaging speed, improved image quality, and more compact geometry. We are developing a high-brightness multiple-pixel thermionic emission x-ray (MPTEX) source based on oxide-coated cathodes. Oxide cathodes have high emission efficiency and, thereby, produce high emission current density at low temperature when compared to traditional tungsten filaments. Indirectly heated micro-rectangular oxide cathodes were developed using carbonates, which were converted to semiconductor oxides of barium, strontium, and calcium after activation. Each cathode produces a focal spot on an elongated fixed anode. The x-ray beam ON and OFF control is performed by source-switching electronics, which supplies bias voltage to the cathode emitters. In this paper, we report the initial performance of the oxide-coated cathodes and the MPTEX source.

Impacts of Four SO2 Oxidation Pathways on Wintertime Sulfate Concentrations

NASA Astrophysics Data System (ADS)

Sarwar, G.; Fahey, K.; Zhang, Y.; Kang, D.; Mathur, R.; Xing, J.; Wei, C.; Cheng, Y.

2017-12-01

Air quality models tend to under-estimate winter-time sulfate concentrations compared to observed data. Such under-estimations are particularly acute in China where very high concentrations of sulfate have been measured. Sulfate is produced by oxidation of sulfur dioxide (SO2) in gas-phase by hydroxyl radical and in aqueous-phase by hydrogen peroxide, ozone, etc. and most air quality models employ such typical reactions. Several additional SO2 oxidation pathways have recently been proposed. Heterogeneous reaction on dust has been suggested to be an important sink for SO2. Oxidation of SO2 on fine particles in presence of nitrogen dioxide (NO2) and ammonia (NH3) at high relative humidity has been implicated for sulfate formation in Chinese haze and London fog. Reactive nitrogen chemistry in aerosol water has also been suggested to produce winter-time sulfate in China. Specifically, high aerosol water can trap SO2 which can be subsequently oxidized by NO2 to form sulfate. Aqueous-phase (in-cloud) oxidation of SO2 by NO2 can also produce sulfate. Here, we use the hemispheric Community Multiscale Air Quality (CMAQ) modeling system to examine the potential impacts of these SO2 oxidation pathways on sulfate formation. We use anthropogenic emissions from the Emissions Database for Global Atmospheric Research and biogenic emissions from Global Emissions InitiAtive. We performed simulations without and with these SO2 oxidation pathways for October-December of 2014 using meteorological fields obtained from the Weather Research and Forecasting model. The standard CMAQ model contains one gas-phase chemical reaction and five aqueous-phase chemical reactions for SO2 oxidation. We implement four additional SO2 oxidation pathways into the CMAQ model. Our preliminary results suggest that the dust chemistry enhances mean sulfate over parts of China and Middle-East, the in-cloud SO2 oxidation by NO2 enhances sulfate over parts of western Europe, oxidation of SO2 by NO2 and NH3 on fine particles enhances sulfate only over parts of China, and SO2 oxidation by NO2 in aerosol water enhances sulfate only over parts of China by >5%. We will present a detailed analysis of the results and a comparison of model predictions with available observed data.

Epitaxial Growth of Intermetallic MnPt Films on Oxides and Large Exchange Bias

DOE PAGES

Liu, Zhiqi; Biegalski, Michael D; Hsu, Mr. S. L.; ...

2015-11-05

We achieved a high-quality epitaxial growth of inter­metallic MnPt films on oxides, with potential for multiferroic heterostructure applications. Also, antisite-stabilized spin-flipping induces ferromagnetism in MnPt films, although it is robustly antiferromagnetic in bulk. Moreover, highly ordered antiferromagnetic MnPt films exhibit superiorly large exchange coupling with a ferromagnetic layer.

Avoiding polar catastrophe in the growth of polarly orientated nickel perovskite thin films by reactive oxide molecular beam epitaxy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, H. F.; Liu, Z. T.; Fan, C. C.

2016-08-15

By means of the state-of-the-art reactive oxide molecular beam epitaxy, we synthesized (001)- and (111)-orientated polar LaNiO{sub 3} thin films. In order to avoid the interfacial reconstructions induced by polar catastrophe, screening metallic Nb-doped SrTiO{sub 3} and iso-polarity LaAlO{sub 3} substrates were chosen to achieve high-quality (001)-orientated films in a layer-by-layer growth mode. For largely polar (111)-orientated films, we showed that iso-polarity LaAlO{sub 3} (111) substrate was more suitable than Nb-doped SrTiO{sub 3}. In situ reflection high-energy electron diffraction, ex situ high-resolution X-ray diffraction, and atomic force microscopy were used to characterize these films. Our results show that special attentionsmore » need to be paid to grow high-quality oxide films with polar orientations, which can prompt the explorations of all-oxide electronics and artificial interfacial engineering to pursue intriguing emergent physics like proposed interfacial superconductivity and topological phases in LaNiO{sub 3} based superlattices.« less

Thermal oxidation of silicon in a residual oxygen atmosphere—the RESOX process—for self-limiting growth of thin silicon dioxide films

NASA Astrophysics Data System (ADS)

Wright, Jason T.; Carbaugh, Daniel J.; Haggerty, Morgan E.; Richard, Andrea L.; Ingram, David C.; Kaya, Savas; Jadwisienczak, Wojciech M.; Rahman, Faiz

2016-10-01

We describe in detail the growth procedures and properties of thermal silicon dioxide grown in a limited and dilute oxygen atmosphere. Thin thermal oxide films have become increasingly important in recent years due to the continuing down-scaling of ultra large scale integration metal oxide silicon field effect transistors. Such films are also of importance for organic transistors where back-gating is needed. The technique described here is novel and allows self-limited formation of high quality thin oxide films on silicon surfaces. This technique is easy to implement in both research laboratory and industrial settings. Growth conditions and their effects on film growth have been described. Properties of the resulting oxide films, relevant for microelectronic device applications, have also been investigated and reported here. Overall, our findings are that thin, high quality, dense silicon dioxide films of thicknesses up to 100 nm can be easily grown in a depleted oxygen environment at temperatures similar to that used for usual silicon dioxide thermal growth in flowing dry oxygen.

Complete Genome Sequence of Nitrosomonas cryotolerans ATCC 49181, a Phylogenetically Distinct Ammonia-Oxidizing Bacterium Isolated from Arctic Waters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rice, Marlen C.; Norton, Jeanette M.; Stein, Lisa Y.

ABSTRACT Nitrosomonas cryotoleransATCC 49181 is a cold-tolerant marine ammonia-oxidizing bacterium isolated from seawater collected in the Gulf of Alaska. The high-quality complete genome contains a 2.87-Mbp chromosome and a 56.6-kbp plasmid. Chemolithoautotrophic modules encoding ammonia oxidation and CO 2 fixation were identified.

Complete Genome Sequence of Nitrosomonas cryotolerans ATCC 49181, a Phylogenetically Distinct Ammonia-Oxidizing Bacterium Isolated from Arctic Waters

DOE PAGES

Rice, Marlen C.; Norton, Jeanette M.; Stein, Lisa Y.; ...

2017-03-16

ABSTRACT Nitrosomonas cryotoleransATCC 49181 is a cold-tolerant marine ammonia-oxidizing bacterium isolated from seawater collected in the Gulf of Alaska. The high-quality complete genome contains a 2.87-Mbp chromosome and a 56.6-kbp plasmid. Chemolithoautotrophic modules encoding ammonia oxidation and CO 2 fixation were identified.

Solvent polarity effect on quality of n-octadecanethiol self-assembled monolayers on copper and oxidized copper

NASA Astrophysics Data System (ADS)

Zhang, Yaozhong; Zhou, Jun; Zhang, Xiaoli; Hu, Jun; Gao, Han

2014-11-01

This article reports the effect of solvent polarity on the formation of n-octadecanethiol self-assembled monolayers (C18SH-SAMs) on pure copper surface and oxidized copper surface. The quality of SAMs prepared in different solvents (n-hexane, toluene, trichloroethylene, chloroform, acetone, acetonitrile, ethanol) was monitored by EIS, RAIRS and XPS. The results indicated that C18SH-SAMs formed in these solvents were in good barrier properties on pure copper surface and the structures of monolayers formed in high polarity solvents were more compact and orderly than that formed in low polarity solvents. For comparison, C18SH adsorbed on the surface of oxidized copper in these solvents were studied and the results indicated that C18SH could be adsorbed on oxidized copper surface after the reduction of copper oxide layer by thiols. Compared with high polarity solvents, a limited reduction process of oxidized copper by thiols led to the incompletely formation of monolayers in low polarity solvents. This can be interpreted that the generated water on solid-liquid interface and a smaller reaction force restrict the continuous reduction reaction in low polarity solvents

Color, lipid oxidation, sensory quality, and aroma compounds of beef steaks displayed under different levels of oxygen in a modified atmosphere package.

PubMed

Resconi, Virginia Celia; Escudero, Ana; Beltrán, José Antonio; Olleta, José Luis; Sañudo, Carlos; Campo, María del Mar

2012-01-01

High oxygen modified atmosphere packaging (MAP) is currently used by the industry to maintain an attractive color in fresh meat. However, it can also promote lipid oxidation and sensory changes. The aim of this study was to compare the quality of beef steaks displayed under different levels of oxygen. For that purpose, meat was stored with 50%, 60%, and 80% of oxygen for 4 and 8 d at retail conditions. A control treatment with steaks vacuum packaged, without exposure to retail display, was included, and color, lipid oxidation, organoleptic characteristics, and aroma compounds were analyzed. Steaks displayed under high oxygen MAP with 50% of oxygen showed the lowest color stability, according to hue values. Higher oxygen levels did not necessarily correspond with higher rancidity levels in the raw meat. Thiobarbituric Acid Reacting Substances (TBARS) values were higher than 2.2 mg malonaldehyde (MDA)/kg muscle in all the samples displayed for 8 d at retail conditions. These samples exhibited the highest intensities of rancid and the least intense beef odors and flavors. The ketones: 2,3-butanedione, 2-octanone, 2,3-pentanedione, 2-heptanone, 4-methyl-2-pentanone, and the aldehydes: pentanal, 2-methyl-butanal, and 2-furfurylthiol, 1-octen-3-ol and 2-methylpropyl-acetate, were proposed as candidates for the aroma differences between the cooked beef steaks stored under vacuum and high oxygen packs. High oxygen modified atmosphere packaging (MAP) is used to increase shelf-life and color at the retail level. However, oxygen deteriorates faster some quality attributes, being a contributor to lipid oxidation that could be perceived at consumption. This study attempts to find the best gas composition in a MAP in order to maintain the color, minimizing the oxidation. Aromatically relevant chemicals have been analyzed by gas olfactometry-gas chromatography as a key to measure beef oxidation after display. © 2011 Institute of Food Technologists®

Improved high temperature integration of Al{sub 2}O{sub 3} on MoS{sub 2} by using a metal oxide buffer layer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Son, Seokki; Choi, Moonseok; Kim, Dohyung

2015-01-12

We deposited a metal oxide buffer layer before atomic layer deposition (ALD) of Al{sub 2}O{sub 3} onto exfoliated molybdenum disulfide (MoS{sub 2}) in order to accomplish enhanced integration. We demonstrate that even at a high temperature, functionalization of MoS{sub 2} by means of a metal oxide buffer layer can effectively provide nucleation sites for ALD precursors, enabling much better surface coverage of Al{sub 2}O{sub 3}. It is shown that using a metal oxide buffer layer not only allows high temperature ALD process, resulting in highly improved quality of Al{sub 2}O{sub 3}/MoS{sub 2} interface, but also leaves MoS{sub 2} intact.

Process for etching mixed metal oxides

DOEpatents

Ashby, Carol I. H.; Ginley, David S.

1994-01-01

An etching process using dicarboxylic and tricarboxylic acids as chelating etchants for mixed metal oxide films such as high temperature superconductors and ferroelectric materials. Undesirable differential etching rates between different metal oxides are avoided by selection of the proper acid or combination of acids. Feature sizes below one micron, excellent quality vertical edges, and film thicknesses in the 100 Angstom range may be achieved by this method.

Characteristics of rose hip (Rosa canina L.) cold-pressed oil and its oxidative stability studied by the differential scanning calorimetry method.

PubMed

Grajzer, Magdalena; Prescha, Anna; Korzonek, Katarzyna; Wojakowska, Anna; Dziadas, Mariusz; Kulma, Anna; Grajeta, Halina

2015-12-01

Two new commercially available high linolenic oils, pressed at low temperature from rose hip seeds, were characterised for their composition, quality and DPPH radical scavenging activity. The oxidative stability of oils was assessed using differential scanning calorimetry (DSC). Phytosterols, tocopherols and carotenoids contents were up to 6485.4; 1124.7; and 107.7 mg/kg, respectively. Phenolic compounds determined for the first time in rose hip oil totalled up to 783.55 μg/kg, with a predominant presence of p-coumaric acid methyl ester. Antiradical activity of the oils reached up to 3.00 mM/kg TEAC. The acid, peroxide and p-anisidine values as well as iron and copper contents indicated good quality of the oils. Relatively high protection against oxidative stress in the oils seemed to be a result of their high antioxidant capacity and the level of unsaturation of fatty acids. Copyright © 2015 Elsevier Ltd. All rights reserved.

Self-cleaning and surface chemical reactions during hafnium dioxide atomic layer deposition on indium arsenide.

PubMed

Timm, Rainer; Head, Ashley R; Yngman, Sofie; Knutsson, Johan V; Hjort, Martin; McKibbin, Sarah R; Troian, Andrea; Persson, Olof; Urpelainen, Samuli; Knudsen, Jan; Schnadt, Joachim; Mikkelsen, Anders

2018-04-12

Atomic layer deposition (ALD) enables the ultrathin high-quality oxide layers that are central to all modern metal-oxide-semiconductor circuits. Crucial to achieving superior device performance are the chemical reactions during the first deposition cycle, which could ultimately result in atomic-scale perfection of the semiconductor-oxide interface. Here, we directly observe the chemical reactions at the surface during the first cycle of hafnium dioxide deposition on indium arsenide under realistic synthesis conditions using photoelectron spectroscopy. We find that the widely used ligand exchange model of the ALD process for the removal of native oxide on the semiconductor and the simultaneous formation of the first hafnium dioxide layer must be significantly revised. Our study provides substantial evidence that the efficiency of the self-cleaning process and the quality of the resulting semiconductor-oxide interface can be controlled by the molecular adsorption process of the ALD precursors, rather than the subsequent oxide formation.

Genome Sequence of an Ammonia-Oxidizing Soil Archaeon, “Candidatus Nitrosoarchaeum koreensis” MY1

PubMed Central

Kim, Byung Kwon; Jung, Man-Young; Yu, Dong Su; Park, Soo-Je; Oh, Tae Kwang; Rhee, Sung-Keun; Kim, Jihyun F.

2011-01-01

Ammonia-oxidizing archaea are ubiquitous microorganisms which play important roles in global nitrogen and carbon cycle on earth. Here we present the high-quality draft genome sequence of an ammonia-oxidizing archaeon, “Candidatus Nitrosopumilus koreensis” MY1, that dominated an enrichment culture of a soil sample from the rhizosphere. Its genome contains genes for survival in the rhizosphere environment as well as those for carbon fixation and ammonium oxidation to nitrite. PMID:21914867

A spectrally tunable all-graphene-based flexible field-effect light-emitting device

NASA Astrophysics Data System (ADS)

Wang, Xiaomu; Tian, He; Mohammad, Mohammad Ali; Li, Cheng; Wu, Can; Yang, Yi; Ren, Tian-Ling

2015-07-01

The continuous tuning of the emission spectrum of a single light-emitting diode (LED) by an external electrical bias is of great technological significance as a crucial property in high-quality displays, yet this capability has not been demonstrated in existing LEDs. Graphene, a tunable optical platform, is a promising medium to achieve this goal. Here we demonstrate a bright spectrally tunable electroluminescence from blue (~450 nm) to red (~750 nm) at the graphene oxide/reduced-graphene oxide interface. We explain the electroluminescence results from the recombination of Poole-Frenkel emission ionized electrons at the localized energy levels arising from semi-reduced graphene oxide, and holes from the top of the π band. Tuning of the emission wavelength is achieved by gate modulation of the participating localized energy levels. Our demonstration of current-driven tunable LEDs not only represents a method for emission wavelength tuning but also may find applications in high-quality displays.

High-Fructose Consumption Impairs the Redox System and Protein Quality Control in the Brain of Syrian Hamsters: Therapeutic Effects of Melatonin.

PubMed

Bermejo-Millo, Juan Carlos; Guimarães, Marcela Rodrigues Moreira; de Luxán-Delgado, Beatriz; Potes, Yaiza; Pérez-Martínez, Zulema; Díaz-Luis, Andrea; Caballero, Beatriz; Solano, Juan José; Vega-Naredo, Ignacio; Coto-Montes, Ana

2018-02-28

Although numerous studies have demonstrated the harmful effect of excessive fructose consumption at the systemic level, there is little information on its effects in the central nervous system. The purpose of the present work was to study the cellular alterations related to oxidative stress and protein quality control systems induced by a high-fructose diet in the brain of Syrian hamsters and their possible attenuation by exogenous melatonin. High-fructose intake induced type II diabetes together with oxidative damage, led to alterations of the unfolded protein response by activating the eIF2α branch, and impaired the macroautophagic machinery in the brain, favoring the accumulation of aggregates labeled for selective degradation and neurodegeneration markers such as β-amyloid (1-42), tau-p-S199, and tau-p-S404. Melatonin attenuated the manifestation of type II diabetes and reduced oxidative stress, deactivated eIF2α, and decreased tau-p-S404 levels in the brain of animals fed a high-fructose diet.

Process for etching mixed metal oxides

DOEpatents

Ashby, C.I.H.; Ginley, D.S.

1994-10-18

An etching process is described using dicarboxylic and tricarboxylic acids as chelating etchants for mixed metal oxide films such as high temperature superconductors and ferroelectric materials. Undesirable differential etching rates between different metal oxides are avoided by selection of the proper acid or combination of acids. Feature sizes below one micron, excellent quality vertical edges, and film thicknesses in the 100 Angstrom range may be achieved by this method. 1 fig.

Enzymatic oxidation of rutin by horseradish peroxidase: kinetic mechanism and identification of a dimeric product by LC-Orbitrap mass spectrometry.

PubMed

Savic, Sasa; Vojinovic, Katarina; Milenkovic, Sanja; Smelcerovic, Andrija; Lamshoeft, Marc; Petronijevic, Zivomir

2013-12-15

Flavonoid oxidation is important issue in food processing and quality. The kinetic mechanism of enzymatic oxidation of rutin by horseradish peroxidase (HRP) was studied. Rutin oxidation reaction was followed by recording of spectral changes over the time at 360 nm. The studied oxidation is mostly enzymatic and less part non-enzymatic. The reaction with HRP has a higher rate compared with the reaction without of HRP, whereby is part of non-enzymatic reaction about 10% of the total reaction. Kinetic parameters were determined from graphics of linear Michaelis-Menten equation, and it was found that investigated reactions of rutin oxidation by HRP take place in a ping-pong kinetic mechanism. High resolution HPLC-MS analysis of the mixture of oxidized products of rutin revealed the presence of rutin dimer. Because of widely distribution of rutin as well as presence of peroxidases and hydrogen peroxide in fresh foods identification of this enzymatic modification product can be beneficial for foods quality and safety. Copyright © 2013 Elsevier Ltd. All rights reserved.

In-line charge-trapping characterization of dielectrics for sub-0.5-um CMOS technologies

NASA Astrophysics Data System (ADS)

Roy, Pradip K.; Chacon, Carlos M.; Ma, Yi; Horner, Gregory

1997-09-01

The advent of ultra-large and giga-scale-integration (ULSI/GSI) has placed considerable emphasis on the development of new gate oxides and interlevel dielectrics capable of meeting strict performance and reliability requirements. The costs and demands associated with ULSI fabrication have in turn fueled the need for cost-effective, rapid and accurate in-line characterization techniques for evaluating dielectric quality. The use of non-contact surface photovoltage characterization techniques provides cost-effective rapid feedback on dielectric quality, reducing costs through the reutilization of control wafers and the elimination of processing time. This technology has been applied to characterize most of the relevant C-V parameters, including flatband voltage (Vfb), density of interface traps (Dit), mobile charge density (Qm), oxide thickness (Tox), oxide resistivity (pox) and total charge (Qtot) for gate and interlevel (ILO) oxides. A novel method of measuring tunneling voltage by this technique on various gate oxides is discussed. For ILO, PECVD and high density plasma dielectrics, surface voltage maps are also presented. Measurements of near-surface silicon quality are described, including minority carrier generation lifetime, and examples of their application in diagnosing manufacturing problems.

A feasible strategy to balance the crystallinity and specific surface area of metal oxide nanocrystals

NASA Astrophysics Data System (ADS)

Zhang, Q. P.; Xu, X. N.; Liu, Y. T.; Xu, M.; Deng, S. H.; Chen, Y.; Yuan, H.; Yu, F.; Huang, Y.; Zhao, K.; Xu, S.; Xiong, G.

2017-04-01

Practical, efficient synthesis of metal oxide nanocrystals with good crystallinity and high specific surface area by a modified polymer-network gel method is demonstrated, taking ZnO nanocrystals as an example. A novel stepwise heat treatment yields significant improvement in crystal quality. Such nanophase materials can effectively degrade common organic dyes under solar radiation and can perform very well in photo-assisted detection of NO2 gas. Other typical metal oxide nanocrystals with good crystallinity and high specific surface area were also synthesized successfully under similar conditions. This work provides a general strategy for the synthesis of metal oxide nanocrystals, balancing the crystallinity and specific surface area.

Photochemical oxidant transport - Mesoscale lake breeze and synoptic-scale aspects

NASA Technical Reports Server (NTRS)

Lyons, W. A.; Cole, H. S.

1976-01-01

Data from routine ozone monitoring in southeastern Wisconsin and limited monitoring of the Milwaukee area by the Environmental Protection Agency are examined. Hourly averages as high as 30 pphm have been recorded in southeastern Wisconsin, and high readings have been reported in rural regions throughout the state. The observations indicate that photochemical oxidants and their nitrogen oxide and reactive hydrocarbon precursers advect from Chicago and northern Indiana into southeastern Wisconsin. There is evidence that synoptic-scale transport of photochemical oxidants occurs, allowing the pollution of entire anticyclones. These results cast doubt on the validity of the Air Quality Control Regions established by amendment to the Clean Air Act of 1970.

Optical properties of spin-on deposited low temperature titanium oxide thin films

NASA Astrophysics Data System (ADS)

Rantala, J. T.; Kärkkäinen, A. H. O.

2003-06-01

This letter presents a method to fabricate high quality, high refractive index titanium oxide thin films by applying liquid phase spin-on deposition combined with low temperature annealing. The synthesis of the liquid form titanium oxide material is carried out using a sol-gel synthesis technique. The material can be annealed at low temperature (150 C°) to achieve relatively high refractive index of 1.94 at 632.8 nm wavelength, whereas annealing at 350 C° results in index of 2.03 at 632.8 nm. Film depositions are demonstrated on silicon substrates with 0.5% uniformity in thickness. Refractive indices and extinction coefficients are characterized over a broad wavelength range to demonstrate the optical performance of this novel aqueous phase spin-on deposited hybrid titanium oxide material.

Oxidative Stress Associated with Chilling Injury in Immature Fruit: Postharvest Technological and Biotechnological Solutions.

PubMed

Valenzuela, Juan Luis; Manzano, Susana; Palma, Francisco; Carvajal, Fátima; Garrido, Dolores; Jamilena, Manuel

2017-07-08

Immature, vegetable-like fruits are produced by crops of great economic importance, including cucumbers, zucchini, eggplants and bell peppers, among others. Because of their high respiration rates, associated with high rates of dehydration and metabolism, and their susceptibility to chilling injury (CI), vegetable fruits are highly perishable commodities, requiring particular storage conditions to avoid postharvest losses. This review focuses on the oxidative stress that affects the postharvest quality of vegetable fruits under chilling storage. We define the physiological and biochemical factors that are associated with the oxidative stress and the development of CI symptoms in these commodities, and discuss the different physical, chemical and biotechnological approaches that have been proposed to reduce oxidative stress while enhancing the chilling tolerance of vegetable fruits.

Oxidative Stress Associated with Chilling Injury in Immature Fruit: Postharvest Technological and Biotechnological Solutions

PubMed Central

Valenzuela, Juan Luis; Manzano, Susana; Palma, Francisco; Carvajal, Fátima; Jamilena, Manuel

2017-01-01

Immature, vegetable-like fruits are produced by crops of great economic importance, including cucumbers, zucchini, eggplants and bell peppers, among others. Because of their high respiration rates, associated with high rates of dehydration and metabolism, and their susceptibility to chilling injury (CI), vegetable fruits are highly perishable commodities, requiring particular storage conditions to avoid postharvest losses. This review focuses on the oxidative stress that affects the postharvest quality of vegetable fruits under chilling storage. We define the physiological and biochemical factors that are associated with the oxidative stress and the development of CI symptoms in these commodities, and discuss the different physical, chemical and biotechnological approaches that have been proposed to reduce oxidative stress while enhancing the chilling tolerance of vegetable fruits. PMID:28698472

Resonant tunnelling in a quantum oxide superlattice

DOE PAGES

Choi, Woo Seok; Lee, Sang A.; You, Jeong Ho; ...

2015-06-24

Resonant tunneling is a quantum mechanical process that has long been attracting both scientific and technological attention owing to its intriguing underlying physics and unique applications for high-speed electronics. The materials system exhibiting resonant tunneling, however, has been largely limited to the conventional semiconductors, partially due to their excellent crystalline quality. Here we show that a deliberately designed transition metal oxide superlattice exhibits a resonant tunneling behaviour with a clear negative differential resistance. The tunneling occurred through an atomically thin, lanthanum δ- doped SrTiO 3 layer, and the negative differential resistance was realized on top of the bi-polar resistance switchingmore » typically observed for perovskite oxide junctions. This combined process resulted in an extremely large resistance ratio (~10 5) between the high and low resistance states. Lastly, the unprecedentedly large control found in atomically thin δ-doped oxide superlattices can open a door to novel oxide-based high-frequency logic devices.« less

Evaluation of the effect of sulfate, alkalinity and disinfector on iron release of iron pipe and iron corrosion scale characteristics under water quality changing condition using response surface methodology

NASA Astrophysics Data System (ADS)

Yang, Fan; Shi, Baoyou; Zhang, Weiyu; Guo, Jianbo; Wu, Nana; Liu, Xinyuan

2018-02-01

The response surface methodology (RSM), particularly Box-Behnken design model, was used in this study to evaluate the sulfate, alkalinity and free chlorine on iron release of pipe with groundwater supply history and its iron corrosion scale characteristics under water quality changing experiment. The RSM results together with response surface contour plots indicated that the iron release of pipe section reactors was positively related with Larson Ratio and free chlorine. The thin Corrosion scales with groundwater supply history upon collection site contained Fe3O4 (18%), α-FeOOH (64%), FeCO3 (9%), β-FeOOH (8%) and γ-FeOOH (5%), besides their averaged amorphous iron oxide content was 13.6%. After the RSM water quality changing experiment, Fe3O4, amorphous iron oxide and intermediate iron products (FeCO3, Green Rust (GR)) content on scale of Cl2Rs increased, while their α-FeOOH contents decreased and β-FeOOH disappeared. The high iron released Cl2Rs receiving higher LR water (1.40-2.04) contained highest FeCO3 (20%) and amorphous iron oxide (42%), while the low iron release Cl2Rs receiving lower LR water (0.52-0.73) had higher GR(6.5%) and the amorphous iron oxide (23.7%). In high LR water (>0.73), the thin and non-protective corrosion scale containing higher amorphous iron oxide, Fe(II) derived from new produced Fe3O4 or FeCO3 or GR was easy for oxidants and sulfate ions penetration, and had higher iron release. However the same unstable corrosion scale didn’t have much iron release in low LR water (≤0.73). RSM experiment indicated that iron release of these unstable corrosion scales had close relationship with water quality (Larson Ratio and disinfectant). Optimizing the water quality of new source water and using reasonable water purification measures can help to eliminate the red water case.

Enhanced electrical and optical properties of room temperature deposited Aluminium doped Zinc Oxide (AZO) thin films by excimer laser annealing

NASA Astrophysics Data System (ADS)

El hamali, S. O.; Cranton, W. M.; Kalfagiannis, N.; Hou, X.; Ranson, R.; Koutsogeorgis, D. C.

2016-05-01

High quality transparent conductive oxides (TCOs) often require a high thermal budget fabrication process. In this study, Excimer Laser Annealing (ELA) at a wavelength of 248 nm has been explored as a processing mechanism to facilitate low thermal budget fabrication of high quality aluminium doped zinc oxide (AZO) thin films. 180 nm thick AZO films were prepared by radio frequency magnetron sputtering at room temperature on fused silica substrates. The effects of the applied RF power and the sputtering pressure on the outcome of ELA at different laser energy densities and number of pulses have been investigated. AZO films deposited with no intentional heating at 180 W, and at 2 mTorr of 0.2% oxygen in argon were selected as the optimum as-deposited films in this work, with a resistivity of 1×10-3 Ω.cm, and an average visible transmission of 85%. ELA was found to result in noticeably reduced resistivity of 5×10-4 Ω.cm, and enhancing the average visible transmission to 90% when AZO is processed with 5 pulses at 125 mJ/cm2. Therefore, the combination of RF magnetron sputtering and ELA, both low thermal budget and scalable techniques, can provide a viable fabrication route of high quality AZO films for use as transparent electrodes.

High-quality crystalline yttria-stabilized-zirconia thin layer for photonic applications

NASA Astrophysics Data System (ADS)

Marcaud, Guillaume; Matzen, Sylvia; Alonso-Ramos, Carlos; Le Roux, Xavier; Berciano, Mathias; Maroutian, Thomas; Agnus, Guillaume; Aubert, Pascal; Largeau, Ludovic; Pillard, Valérie; Serna, Samuel; Benedikovic, Daniel; Pendenque, Christopher; Cassan, Eric; Marris-Morini, Delphine; Lecoeur, Philippe; Vivien, Laurent

2018-03-01

Functional oxides are considered as promising materials for photonic applications due to their extraordinary and various optical properties. Especially, yttria-stabilized zirconia (YSZ) has a high refractive index (˜2.15), leading to a good confinement of the optical mode in waveguides. Furthermore, YSZ can also be used as a buffer layer to expand toward a large family of oxides-based thin-films heterostructures. In this paper, we report a complete study of the structural properties of YSZ for the development of integrated optical devices on sapphire in telecom wavelength range. The substrate preparation and the epitaxial growth using pulsed-laser deposition technique have been studied and optimized. High-quality YSZ thin films with remarkably sharp x-ray diffraction rocking curve peaks in 10-3∘ range have then been grown on sapphire (0001). It was demonstrated that a thermal annealing of sapphire substrate before the YSZ growth allowed controlling the out-of-plane orientation of the YSZ thin film. Single-mode waveguides were finally designed, fabricated, and characterized for two different main orientations of high-quality YSZ (001) and (111). Propagation loss as low as 2 dB/cm at a wavelength of 1380 nm has been demonstrated for both orientations. These results pave the way for the development of a functional oxides-based photonics platform for numerous applications including on-chip optical communications and sensing.

Comparative study on nitridation and oxidation plasma interface treatment for AlGaN/GaN MIS-HEMTs with AlN gate dielectric

NASA Astrophysics Data System (ADS)

Zhu, Jie-Jie; Ma, Xiao-Hua; Hou, Bin; Chen, Li-Xiang; Zhu, Qing; Hao, Yue

2017-02-01

This paper demonstrated the comparative study on interface engineering of AlN/AlGaN/GaN metal-insulator-semiconductor high-electron-mobility transistors (MIS-HEMTs) by using plasma interface pre-treatment in various ambient gases. The 15 nm AlN gate dielectric grown by plasma-enhanced atomic layer deposition significantly suppressed the gate leakage current by about two orders of magnitude and increased the peak field-effect mobility by more than 50%. NH3/N2 nitridation plasma treatment (NPT) was used to remove the 3 nm poor-quality interfacial oxide layer and N2O/N2 oxidation plasma treatment (OPT) to improve the quality of interfacial layer, both resulting in improved dielectric/barrier interface quality, positive threshold voltage (V th) shift larger than 0.9 V, and negligible dispersion. In comparison, however, NPT led to further decrease in interface charges by 3.38 × 1012 cm-2 and an extra positive V th shift of 1.3 V. Analysis with fat field-effect transistors showed that NPT resulted in better sub-threshold characteristics and transconductance linearity for MIS-HEMTs compared with OPT. The comparative study suggested that direct removing the poor interfacial oxide layer by nitridation plasma was superior to improving the quality of interfacial layer by oxidation plasma for the interface engineering of GaN-based MIS-HEMTs.

40 CFR 50.11 - National primary and secondary ambient air quality standards for oxides of nitrogen (with...

Code of Federal Regulations, 2014 CFR

2014-07-01

... air quality standards for oxides of nitrogen (with nitrogen dioxide as the indicator). 50.11 Section... quality standards for oxides of nitrogen (with nitrogen dioxide as the indicator). (a) The level of the national primary annual ambient air quality standard for oxides of nitrogen is 53 parts per billion (ppb...

40 CFR 50.11 - National primary and secondary ambient air quality standards for oxides of nitrogen (with...

Code of Federal Regulations, 2012 CFR

2012-07-01

... air quality standards for oxides of nitrogen (with nitrogen dioxide as the indicator). 50.11 Section... quality standards for oxides of nitrogen (with nitrogen dioxide as the indicator). (a) The level of the national primary annual ambient air quality standard for oxides of nitrogen is 53 parts per billion (ppb...

40 CFR 50.11 - National primary and secondary ambient air quality standards for oxides of nitrogen (with...

Code of Federal Regulations, 2013 CFR

2013-07-01

... air quality standards for oxides of nitrogen (with nitrogen dioxide as the indicator). 50.11 Section... quality standards for oxides of nitrogen (with nitrogen dioxide as the indicator). (a) The level of the national primary annual ambient air quality standard for oxides of nitrogen is 53 parts per billion (ppb...

Growth and characterization of single phase Cu{sub 2}O by thermal oxidation of thin copper films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Choudhary, Sumita; Sarma, J. V. N.; Gangopadhyay, Subhashis, E-mail: subhagan@yahoo.com

2016-04-13

We report a simple and efficient technique to form high quality single phase cuprous oxide films on glass substrate using thermal evaporation of thin copper films followed by controlled thermal oxidation in air ambient. Crystallographic analysis and oxide phase determination, as well as grain size distribution have been studied using X-ray diffraction (XRD) method, while scanning electron microscopy (SEM) has been utilized to investigate the surface morphology of the as grown oxide films. The formation of various copper oxide phases is found to be highly sensitive to the oxidation temperature and a crystalline, single phase cuprous oxide film can bemore » achieved for oxidation temperatures between 250°C to 320°C. Cu{sub 2}O film surface appeared in a faceted morphology in SEM imaging and a direct band gap of about 2.1 eV has been observed in UV-visible spectroscopy. X-ray photoelectron spectroscopy (XPS) confirmed a single oxide phase formation. Finally, a growth mechanism of the oxide film has also been discussed.« less

Exposure to Heavy Ion Radiation Induces Persistent Oxidative Stress in Mouse Intestine

PubMed Central

Datta, Kamal; Suman, Shubhankar; Kallakury, Bhaskar V. S.; Fornace, Albert J.

2012-01-01

Ionizing radiation-induced oxidative stress is attributed to generation of reactive oxygen species (ROS) due to radiolysis of water molecules and is short lived. Persistent oxidative stress has also been observed after radiation exposure and is implicated in the late effects of radiation. The goal of this study was to determine if long-term oxidative stress in freshly isolated mouse intestinal epithelial cells (IEC) is dependent on radiation quality at a dose relevant to fractionated radiotherapy. Mice (C57BL/6J; 6 to 8 weeks; female) were irradiated with 2 Gy of γ-rays, a low-linear energy transfer (LET) radiation, and intestinal tissues and IEC were collected 1 year after radiation exposure. Intracellular ROS, mitochondrial function, and antioxidant activity in IEC were studied by flow cytometry and biochemical assays. Oxidative DNA damage, cell death, and mitogenic activity in IEC were assessed by immunohistochemistry. Effects of γ radiation were compared to 56Fe radiation (iso-toxic dose: 1.6 Gy; energy: 1000 MeV/nucleon; LET: 148 keV/µm), we used as representative of high-LET radiation, since it's one of the important sources of high Z and high energy (HZE) radiation in cosmic rays. Radiation quality affected the level of persistent oxidative stress with higher elevation of intracellular ROS and mitochondrial superoxide in high-LET 56Fe radiation compared to unirradiated controls and γ radiation. NADPH oxidase activity, mitochondrial membrane damage, and loss of mitochondrial membrane potential were greater in 56Fe-irradiated mice. Compared to γ radiation oxidative DNA damage was higher, cell death ratio was unchanged, and mitotic activity was increased after 56Fe radiation. Taken together our results indicate that long-term functional dysregulation of mitochondria and increased NADPH oxidase activity are major contributing factors towards heavy ion radiation-induced persistent oxidative stress in IEC with potential for neoplastic transformation. PMID:22936983

Temperature stability of Al(x)Ga(1-x)As (x = 0-1) thermal oxide masks for selective-area epitaxy

NASA Technical Reports Server (NTRS)

Jones, Stephen H.; Lau, Kei May; Pouch, John J.

1988-01-01

The use of thermal oxides of Al(x)Ga(1-x)As (x = 0-1) as masking materials for selective-area epitaxy by a organometallic chemical-vapor deposition has been investigated. It was found that the thermal oxide of GaAs is only applicable for low growth temperatures (less than or equal to 600 C), and the addition of aluminum significantly improves the thermal stability of the oxide. The oxide of Al(0.4)Ga(0.6)As is suitable for high-temperature deposition, but there are criteria for the thickness and oxidation temperature. Thin layers of AlAs oxidized at 475 C are excellent masks and allow precise thickness control. Promising results of selective-area deposition using these aluminum oxide masks have been obtained. High-quality single crystal grew in mask openings uniformly surrounded by dense and fine-grain polycrystalline deposits, producing a planar duplication of the original pattern.

Detection of defects in laser welding of AZ31B magnesium alloy in zero-gap lap joint configuration by a real-time spectroscopic analysis

NASA Astrophysics Data System (ADS)

Harooni, Masoud; Carlson, Blair; Kovacevic, Radovan

2014-05-01

The effect of surface oxide layer existing at the lap-joint faying surface of magnesium sheets is investigated on the keyhole dynamics of the weld pool and weld bead qualities. It is observed that by removing the oxide layer from the faying surface of the lap joint, a high quality weld can be achieved in the laser welding process. However, the presence of an oxide layer deteriorates the quality of the weld by forming pores at the interface of the two overlapped sheets. The purpose of this paper is to identify the correlation between the integrity of the weld and the interaction between the laser and material. A spectroscopy sensor was applied to detect the spectra emitted from a plasma plume during the laser welding of AZ31B magnesium alloy in a zero-gap lap joint configuration. The electron temperature was calculated by applying a Boltzmann plot method based on the detected spectra, and the correlation between the pore formation and the spectral signals was studied. The laser molten pool and the keyhole condition were monitored in real-time by a high speed charge-coupled device (CCD) camera. A green laser was used as an illumination source in order to detect the influence of the oxide layer on the dynamic behavior of the molten pool. Results revealed that the detected spectrum and weld defects had a meaningful correlation for real-time monitoring of the weld quality during laser welding of magnesium alloys.

Identifying suitable substrates for high-quality graphene-based heterostructures

NASA Astrophysics Data System (ADS)

Banszerus, L.; Janssen, H.; Otto, M.; Epping, A.; Taniguchi, T.; Watanabe, K.; Beschoten, B.; Neumaier, D.; Stampfer, C.

2017-06-01

We report on a scanning confocal Raman spectroscopy study investigating the strain-uniformity and the overall strain and doping of high-quality chemical vapour deposited (CVD) graphene-based heterostuctures on a large number of different substrate materials, including hexagonal boron nitride (hBN), transition metal dichalcogenides, silicon, different oxides and nitrides, as well as polymers. By applying a hBN-assisted, contamination free, dry transfer process for CVD graphene, high-quality heterostructures with low doping densities and low strain variations are assembled. The Raman spectra of these pristine heterostructures are sensitive to substrate-induced doping and strain variations and are thus used to probe the suitability of the substrate material for potential high-quality graphene devices. We find that the flatness of the substrate material is a key figure for gaining, or preserving high-quality graphene.

Method of Analysis by the U.S. Geological Survey California District Sacramento Laboratory-- Determination of Dissolved Organic Carbon in Water by High Temperature Catalytic Oxidation, Method Validation, and Quality-Control Practices

USGS Publications Warehouse

Bird, Susan M.; Fram, Miranda S.; Crepeau, Kathryn L.

2003-01-01

An analytical method has been developed for the determination of dissolved organic carbon concentration in water samples. This method includes the results of the tests used to validate the method and the quality-control practices used for dissolved organic carbon analysis. Prior to analysis, water samples are filtered to remove suspended particulate matter. A Shimadzu TOC-5000A Total Organic Carbon Analyzer in the nonpurgeable organic carbon mode is used to analyze the samples by high temperature catalytic oxidation. The analysis usually is completed within 48 hours of sample collection. The laboratory reporting level is 0.22 milligrams per liter.

High Current Plasma Electrolytic Oxidation Coating Processes for Wear and Corrosion Prevention of Al 2024

NASA Astrophysics Data System (ADS)

Wang, Rui

Plasma electrolytic oxidation (PEO) treatments have been used in the aerospace and automotive industries because the coating formed on light metals or alloys has great hardness, high wear, corrosion, and oxidation resistance, and a low friction coefficient that improves lifetime length and provide a higher surface quality. However, the PEO treatments that are presently used for industrial applications require a long period of time to confirm the quality of the coating. For this reason, the present study seeks to increase the current density of PEO treatments to improve their efficiency and explore the performance of the obtained coatings. It was found that for high current density (0.18A/cm2) PEO treatments, smaller ratio, such as 50% and 70%, is beneficial to obtaining a better performance coating. When compared with the coating of a "normal" (current density: 0.09A/cm2) PEO treatment, it had better wear resistance; however, for corrosion resistance, it had a lower performance than the coatings obtained by the "normal" current density PEO treatment which was attributed to the negative influence of porosity increase.

Structural and proactive safety aspects of oxidation debris from multiwalled carbon nanotubes.

PubMed

Stéfani, Diego; Paula, Amauri J; Vaz, Boniek G; Silva, Rodrigo A; Andrade, Nádia F; Justo, Giselle Z; Ferreira, Carmen V; Filho, Antonio G Souza; Eberlin, Marcos N; Alves, Oswaldo L

2011-05-15

The removal of oxidation debris from the oxidized carbon nanotube surface with a NaOH treatment is a key step for an effective functionalization and quality improvement of the carbon nanotube samples. In this work, we show via infrared spectroscopy and ultrahigh resolution and accuracy mass spectrometry that oxidation debris obtained from HNO(3)-treated multiwalled carbon nanotubes is a complex mixture of highly condensed aromatic oxygenated carbonaceous fragments. We have also evaluated their cytotoxicity by using BALB/c 3T3 mouse fibroblasts and HaCaT human keratinocytes as models. By knowing the negative aspects of dissolved organic carbon (DOC) to the water quality, we have demonstrated the removal of these carbon nanotube residues from the NaOH solution (wastewater) by using aluminium sulphate, which is a standard coagulant agent used in conventional drinking water purification and wastewater treatment plants. Our results contribute to elucidate the structural and proactive safety aspects of oxidation debris from oxidized carbon nanotubes towards a greener nanotechnology. Copyright © 2011 Elsevier B.V. All rights reserved.

OBSERVATION-BASED ASSESSMENT OF THE IMPACT OF NITROGEN OXIDES EMISSIONS REDUCTIONS ON OZONE AIR QUALITY OVER THE EASTERN UNITED STATES

EPA Science Inventory

Ozone is produced by chemical interactions involving nitrogen oxides (NO_x) and Volatile Organic Compounds (VOCs) in the presence of sunlight. At high concentrations, ground-level ozone has been shown to be harmful to human health and the environment. It has been reco...

Application of Pre-heating to Improve the Consistency and Quality in AA5052 Resistance Spot Welding

NASA Astrophysics Data System (ADS)

Luo, Zhen; Ao, Sansan; Chao, Yuh Jin; Cui, Xuetuan; Li, Yang; Lin, Ye

2015-10-01

Making consistent resistance spot welds of aluminum alloy with good quality and at high volume has several obstacles in automotive industry. One of the difficult issues arises from the presence of a tough non-conducting oxide film on the aluminum sheet surface. The oxide film develops over time and often is non-uniform across the surface of the aluminum alloy sheet, which makes the contact resistance characteristics irregular at the faying interface during welding. The consistency in quality of the final spot welds is therefore problematic to control. To suppress the effect of the irregular oxide film on the spot weld quality, application of a pre-heating treatment in the welding schedule for aluminum alloy 5052 is investigated in this present work. The current level of the pre-heating required to reduce the scatter of the contact resistance at the W/W (workpiece-to-workpiece) faying interface is quantified experimentally. The results indicate that the contact resistance at the W/W faying interface with a pre-heating treatment becomes much consistent and can be reduced by two orders of magnitude. Having the uncertain variation of the contact resistance at the W/W faying surface virtually reduced or removed, the quality of the spot welds in terms of the peak load and nugget diameter is examined and shows a great improvement. The proposed method may provide a robust method for high-volume spot welding of aluminum alloy sheets in auto industry.

Protein Oxidation and Sensory Quality of Brine-Injected Pork Loins Added Ascorbate or Extracts of Green Tea or Maté during Chill-Storage in High-Oxygen Modified Atmosphere.

PubMed

Jongberg, Sisse; Tørngren, Mari Ann; Skibsted, Leif H

2018-01-15

Background: Ascorbate is often applied to enhance stability and robustness of brine-injected pork chops sold for retail, but may affect protein oxidation, while plant extracts are potential substitutes. Methods: Brine-injected pork chops (weight-gain ~12%, NaCl ~0.9%) prepared with ascorbate (225 ppm), green tea extract (25 ppm gallic acid equivalents (GAE)), or maté extract (25 ppm GAE) stored (5 °C, seven days) in high-oxygen atmosphere packaging (MAP: 80% O₂ and 20% CO₂) were analyzed for color changes, sensory quality, and protein oxidation compared to a control without antioxidant. Results: No significant differences were observed for green tea and maté extracts as compared to ascorbate when evaluated based on lipid oxidation derived off-flavors, except for stale flavor, which maté significantly reduced. All treatments increased the level of the protein oxidation product, α-aminoadipic semialdehyde as compared to the control, and ascorbate was further found to increase thiol loss and protein cross-linking, with a concomitant decrease in the sensory perceived tenderness. Conclusions: Green tea and maté were found to equally protect against lipid oxidation derived off-flavors, and maté showed less prooxidative activity towards proteins as compared to ascorbate, resulting in more tender meat. Maté is a valuable substitute for ascorbate in brine-injected pork chops.

Effect of high-pressure processing on quality and stability of green mango blended mayonnaise.

PubMed

Sethi, Swati; Chauhan, O P; Anurag, Rahul K

2017-07-01

The present work was aimed to study and optimize the high pressure treated green mango blended mayonnaise in terms of oxidative and emulsion stability, as a function of technical parameters; pressure intensity, dwell period and level of green mango pulp. Mayonnaise samples were treated at different combinations of pressure (400-600 MPa), holding time (5-10 min) and level of green mango pulp (10-30%) following Box-Behnken design. Mayonnaise quality was evaluated in terms of oxidative stability and emulsion stability using response surface methodology to optimize the best possible combination among all. Analysis of variance showed that the second-order polynomial model fitted well with the experimental results. Pressure and time were the most important factors determining the oxidative stability (free fatty acids, peroxide value and anisidine value) whereas; the emulsion stability (creaming and thermal creaming) was most significantly affected by the level of green mango pulp. The optimized conditions for preparing green mango blended mayonnaise with high oxidative and emulsion stability were: 435 MPa pressure, 5 min of holding time with the addition of green mango pulp at the rate of 28%. The product prepared at optimum conditions showed good correlations between predicted and actual values.

[Improvement in quality of life and exercise capacity without muscular biology changes after general training in patients with severe chronic obstructive pulmonary disease].

PubMed

Pascual-Guardia, Sergio; Wodja, Emil; Gorostiza, Amaya; López de Santamaría, Elena; Gea, Joaquim; Gáldiz, Juan B; Sliwinski, Pawel; Barreiro, Esther

2013-03-02

Despite the beneficial effects of exercise training in chronic obstructive pulmonary disease (COPD) patients, several studies have revealed functional and biological abnormalities in their peripheral muscles. The objective was to determine whether exercise training of high intensity and long duration modifies oxidative stress levels and structure of respiratory and peripheral muscles of severe COPD patients, while also improving their exercise capacity and quality of life. Multicenter study (Warsaw and Barakaldo) in which 25 severe COPD out-patients were recruited from the COPD clinics. In all patients, lung and muscle functions, exercise capacity (walking test and cycloergometer) and quality of life (QoL) were assessed, and open muscle biopsies from the vastus lateralis and external intercostals (n=14) were obtained before and after an exercise training program of high intensity (respiratory rehabilitation area, 70% maximal tolerated load in a cycloergometer) and long duration (10 weeks). Oxidative stress and muscle structural modifications were evaluated in all muscle biopsies using immunoblotting and immunohistochemistry. In all patients, after the training program, without any drop-outs, exercise capacity and QoL improved significantly, whereas oxidative stress, muscle damage and structure were not modified in their respiratory or limb muscles compared to baseline. In patients with severe COPD, exercise training of high intensity and long duration significantly improves their exercise capacity and QoL, without inducing significant modifications on oxidative stress levels or muscle structure in their respiratory or peripheral muscles. These results may have future clinical therapeutic implications. Copyright © 2011 Elsevier España, S.L. All rights reserved.

Chronic exposure to emissions from photocopiers in copy shops causes oxidative stress and systematic inflammation among photocopier operators in India.

PubMed

Elango, Nithya; Kasi, Vallikkannu; Vembhu, Bhuvaneswari; Poornima, Jeyanthi Govindasamy

2013-09-11

We assessed indoor air quality in photocopier centers and investigated whether occupational exposure to emissions from photocopiers is associated with decline in lung function or changes in haematological parameters, oxidative stress and inflammatory status. Indoor air quality was monitored in five photocopier centers. Pulmonary function was assessed by spirometry in 81 photocopier operators (64 male and 17 female) and 43 healthy control (31 male and 12 female) subjects. Hematological status, serum thio-barbituric acid reactive substances (TBARS), total ferric reducing antioxidant capacity (FRAC), leukotriene B4 (LTB4), 8-isoprostane, C reactive protein (CRP), interleukin 8 (IL-8), clara cell protein (CC-16), intercellular adhesion molecule 1 (ICAM-1) and eosinophilic cationic protein (ECP) were analyzed. Relationships between cumulative exposure, lung function and inflammatory markers were assessed. PM10 and PM2.5 were above the permissible levels in all the photocopier centers, whereas the levels of carbon monoxide, nitrogen oxides, ozone, sulphur dioxide, lead, arsenic, nickel, ammonia, benzene and benzo(a)pyrene were within Indian ambient air quality standards. Lung function was similar in the photocopier operators and control subjects. Serum TBARS was significantly higher and FRAC was lower among photocopier operators when compared to healthy controls. Plasma IL-8, LTB4, ICAM-1 and ECP were significantly higher in the photocopier exposed group. Photocopiers emit high levels of particulate matter. Long term exposure to emissions from photocopiers was not associated with decreased lung function, but resulted in high oxidative stress and systemic inflammation leading to high risk of cardiovascular diseases.

Chronic exposure to emissions from photocopiers in copy shops causes oxidative stress and systematic inflammation among photocopier operators in India

PubMed Central

2013-01-01

Background We assessed indoor air quality in photocopier centers and investigated whether occupational exposure to emissions from photocopiers is associated with decline in lung function or changes in haematological parameters, oxidative stress and inflammatory status. Methods Indoor air quality was monitored in five photocopier centers. Pulmonary function was assessed by spirometry in 81 photocopier operators (64 male and 17 female) and 43 healthy control (31 male and 12 female) subjects. Hematological status, serum thio-barbituric acid reactive substances (TBARS), total ferric reducing antioxidant capacity (FRAC), leukotriene B4 (LTB4), 8-isoprostane, C reactive protein (CRP), interleukin 8 (IL-8), clara cell protein (CC-16), intercellular adhesion molecule 1 (ICAM-1) and eosinophilic cationic protein (ECP) were analyzed. Relationships between cumulative exposure, lung function and inflammatory markers were assessed. Results PM10 and PM2.5 were above the permissible levels in all the photocopier centers, whereas the levels of carbon monoxide, nitrogen oxides, ozone, sulphur dioxide, lead, arsenic, nickel, ammonia, benzene and benzo(a)pyrene were within Indian ambient air quality standards. Lung function was similar in the photocopier operators and control subjects. Serum TBARS was significantly higher and FRAC was lower among photocopier operators when compared to healthy controls. Plasma IL-8, LTB4, ICAM-1 and ECP were significantly higher in the photocopier exposed group. Conclusions Photocopiers emit high levels of particulate matter. Long term exposure to emissions from photocopiers was not associated with decreased lung function, but resulted in high oxidative stress and systemic inflammation leading to high risk of cardiovascular diseases. PMID:24025094

Microgravity Production of Nanoparticles of Novel Materials Using Plasma Synthesis

NASA Technical Reports Server (NTRS)

Frenklach, Michael; Fernandez-Pello, Carlos

2001-01-01

The research goal is to study the formation in reduced gravity of high quality nanoparticulate of novel materials using plasma synthesis. Particular emphasis will be placed on the production of powders of non-oxide materials like diamond, SiC, SiN, c-BN, etc. The objective of the study is to investigate the effect of gravity on plasma synthesis of these materials, and to determine how the microgravity synthesis can improve the quality and yield of the nanoparticles. It is expected that the reduced gravity will aid in the understanding of the controlling mechanisms of plasma synthesis, and will increase the yield, and quality of the synthesized powder. These materials have properties of interest in several industrial applications, such as high temperature load bearings or high speed metal machining. Furthermore, because of the nano-meter size of the particulate produced in this process, they have specific application in the fabrication of MEMS based combustion systems, and in the development and growth of nano-systems and nano-structures of these materials. These are rapidly advancing research areas, and there is a great need for high quality nanoparticles of different materials. One of the primary systems of interest in the project will be gas-phase synthesis of nanopowder of non-oxide materials.

A spectrally tunable all-graphene-based flexible field-effect light-emitting device

PubMed Central

Wang, Xiaomu; Tian, He; Mohammad, Mohammad Ali; Li, Cheng; Wu, Can; Yang, Yi; Ren, Tian-Ling

2015-01-01

The continuous tuning of the emission spectrum of a single light-emitting diode (LED) by an external electrical bias is of great technological significance as a crucial property in high-quality displays, yet this capability has not been demonstrated in existing LEDs. Graphene, a tunable optical platform, is a promising medium to achieve this goal. Here we demonstrate a bright spectrally tunable electroluminescence from blue (∼450 nm) to red (∼750 nm) at the graphene oxide/reduced-graphene oxide interface. We explain the electroluminescence results from the recombination of Poole–Frenkel emission ionized electrons at the localized energy levels arising from semi-reduced graphene oxide, and holes from the top of the π band. Tuning of the emission wavelength is achieved by gate modulation of the participating localized energy levels. Our demonstration of current-driven tunable LEDs not only represents a method for emission wavelength tuning but also may find applications in high-quality displays. PMID:26178323

Molecular Beam Epitaxy of lithium niobium oxide multifunctional materials

NASA Astrophysics Data System (ADS)

Tellekamp, M. Brooks; Shank, Joshua C.; Doolittle, W. Alan

2017-04-01

The role of stoichiometry and growth temperature in the preferential nucleation of material phases in the Li-Nb-O family are explored yielding an empirical growth phase diagram. It is shown that while single parameter variation often produces multi-phase films, combining substrate temperature control with the previously published lithium flux limited growth allows the repeatable growth of high quality single crystalline films of many different oxide phases. Higher temperatures (800-1050 °C) than normally used in MBE were necessary to achieve high quality materials. At these temperatures the desorption of surface species is shown to play an important role in film composition. Using this method single phase films of NbO, NbO2, LiNbO2, Li3NbO4, LiNbO3, and LiNb3O8 have been achieved in the same growth system, all on c-plane sapphire. Finally, the future of these films in functional oxide heterostructures is briefly discussed.

Single-Crystal Thin Films of Cesium Lead Bromide Perovskite Epitaxially Grown on Metal Oxide Perovskite (SrTiO 3)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Jie; Morrow, Darien J.; Fu, Yongping

High-quality metal halide perovskite single crystals have low defect densities and excellent photophysical properties, yet thin films are the most sought after material geometry for optoelectronic devices. Perovskite single-crystal thin films (SCTFs) would be highly desirable for high-performance devices, but their growth remains challenging, particularly for inorganic metal halide perovskites. Herein, we report the facile vapor-phase epitaxial growth of cesium lead bromide perovskite (CsPbBr 3) continuous SCTFs with controllable micrometer thickness, as well as nanoplate arrays, on traditional oxide perovskite SrTiO 3(100) substrates. Heteroepitaxial single-crystal growth is enabled by the serendipitous incommensurate lattice match between these two perovskites, and overcomingmore » the limitation of island-forming Volmer–Weber crystal growth is critical for growing large-area continuous thin films. Time-resolved photoluminescence, transient reflection spectroscopy, and electrical transport measurements show that the CsPbBr 3 epitaxial thin film has a slow charge carrier recombination rate, low surface recombination velocity (10 4 cm s –1), and low defect density of 10 12 cm –3, which are comparable to those of CsPbBr 3 single crystals. This work suggests a general approach using oxide perovskites as substrates for heteroepitaxial growth of halide perovskites. Furthermore, the high-quality halide perovskite SCTFs epitaxially integrated with multifunctional oxide perovskites could open up opportunities for a variety of high-performance optoelectronics devices.« less

Single-Crystal Thin Films of Cesium Lead Bromide Perovskite Epitaxially Grown on Metal Oxide Perovskite (SrTiO 3)

DOE PAGES

Chen, Jie; Morrow, Darien J.; Fu, Yongping; ...

2017-09-05

High-quality metal halide perovskite single crystals have low defect densities and excellent photophysical properties, yet thin films are the most sought after material geometry for optoelectronic devices. Perovskite single-crystal thin films (SCTFs) would be highly desirable for high-performance devices, but their growth remains challenging, particularly for inorganic metal halide perovskites. Herein, we report the facile vapor-phase epitaxial growth of cesium lead bromide perovskite (CsPbBr 3) continuous SCTFs with controllable micrometer thickness, as well as nanoplate arrays, on traditional oxide perovskite SrTiO 3(100) substrates. Heteroepitaxial single-crystal growth is enabled by the serendipitous incommensurate lattice match between these two perovskites, and overcomingmore » the limitation of island-forming Volmer–Weber crystal growth is critical for growing large-area continuous thin films. Time-resolved photoluminescence, transient reflection spectroscopy, and electrical transport measurements show that the CsPbBr 3 epitaxial thin film has a slow charge carrier recombination rate, low surface recombination velocity (10 4 cm s –1), and low defect density of 10 12 cm –3, which are comparable to those of CsPbBr 3 single crystals. This work suggests a general approach using oxide perovskites as substrates for heteroepitaxial growth of halide perovskites. Furthermore, the high-quality halide perovskite SCTFs epitaxially integrated with multifunctional oxide perovskites could open up opportunities for a variety of high-performance optoelectronics devices.« less

Two-Step Electrochemical Intercalation and Oxidation of Graphite for the Mass Production of Graphene Oxide.

PubMed

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.

Elucidation of the atomic-scale mechanism of the anisotropic oxidation rate of 4H-SiC between the (0001) Si-face and ( 000 1 ¯ ) C-face by using a new Si-O-C interatomic potential

NASA Astrophysics Data System (ADS)

Takamoto, So; Yamasaki, Takahiro; Ohno, Takahisa; Kaneta, Chioko; Hatano, Asuka; Izumi, Satoshi

2018-05-01

Silicon carbide (SiC) is an attractive semiconductor material for applications in power electronic devices. However, fabrication of a high-quality SiC/SiO2 interface has been a challenge. It is well-known that there is a great difference in the oxidation rate between the Si-face and the C-face and that the quality of oxide on the Si-face is greater than that on the C-face. However, the atomistic mechanism of the thermal oxidation of SiC remains to be solved. In this paper, a new Si-O-C interatomic potential was developed to reproduce the kinetics of the thermal oxidation of SiC. Using this newly developed potential, large-scale SiC oxidation simulations at various temperatures were performed. The results showed that the activation energy of the Si-face is much larger than that of the C-face. In the case of the Si-face, a flat and aligned interface structure including Si1+ was created. Based on the estimated activation energies of the intermediate oxide states, it is proposed that the stability of the flat interface structure is the origin of the high activation energy of the oxidation of the Si-face. In contrast, in the case of the C-face, it is found that the Si atom at the interface is easily pulled up by the O atoms. This process generates the disordered interface and decreases the activation energy of the oxidation. It is also proposed that many excess C atoms are created in the case of the C-face.

40 CFR 50.17 - National primary ambient air quality standards for sulfur oxides (sulfur dioxide).

Code of Federal Regulations, 2011 CFR

2011-07-01

... standards for sulfur oxides (sulfur dioxide). 50.17 Section 50.17 Protection of Environment ENVIRONMENTAL....17 National primary ambient air quality standards for sulfur oxides (sulfur dioxide). (a) The level of the national primary 1-hour annual ambient air quality standard for oxides of sulfur is 75 parts...

40 CFR 50.17 - National primary ambient air quality standards for sulfur oxides (sulfur dioxide).

Code of Federal Regulations, 2012 CFR

2012-07-01

... standards for sulfur oxides (sulfur dioxide). 50.17 Section 50.17 Protection of Environment ENVIRONMENTAL....17 National primary ambient air quality standards for sulfur oxides (sulfur dioxide). (a) The level of the national primary 1-hour annual ambient air quality standard for oxides of sulfur is 75 parts...

40 CFR 50.17 - National primary ambient air quality standards for sulfur oxides (sulfur dioxide).

Code of Federal Regulations, 2010 CFR

2010-07-01

... standards for sulfur oxides (sulfur dioxide). 50.17 Section 50.17 Protection of Environment ENVIRONMENTAL....17 National primary ambient air quality standards for sulfur oxides (sulfur dioxide). (a) The level of the national primary 1-hour annual ambient air quality standard for oxides of sulfur is 75 parts...

40 CFR 50.17 - National primary ambient air quality standards for sulfur oxides (sulfur dioxide).

Code of Federal Regulations, 2013 CFR

2013-07-01

... standards for sulfur oxides (sulfur dioxide). 50.17 Section 50.17 Protection of Environment ENVIRONMENTAL....17 National primary ambient air quality standards for sulfur oxides (sulfur dioxide). (a) The level of the national primary 1-hour annual ambient air quality standard for oxides of sulfur is 75 parts...

40 CFR 50.17 - National primary ambient air quality standards for sulfur oxides (sulfur dioxide).

Code of Federal Regulations, 2014 CFR

2014-07-01

... standards for sulfur oxides (sulfur dioxide). 50.17 Section 50.17 Protection of Environment ENVIRONMENTAL....17 National primary ambient air quality standards for sulfur oxides (sulfur dioxide). (a) The level of the national primary 1-hour annual ambient air quality standard for oxides of sulfur is 75 parts...

In situ growth of capping-free magnetic iron oxide nanoparticles on liquid-phase exfoliated graphene

NASA Astrophysics Data System (ADS)

Tsoufis, T.; Syrgiannis, Z.; Akhtar, N.; Prato, M.; Katsaros, F.; Sideratou, Z.; Kouloumpis, A.; Gournis, D.; Rudolf, P.

2015-05-01

We report a facile approach for the in situ synthesis of very small iron oxide nanoparticles on the surface of high-quality graphene sheets. Our synthetic strategy involved the direct, liquid-phase exfoliation of highly crystalline graphite (avoiding any oxidation treatment) and the subsequent chemical functionalization of the graphene sheets via the well-established 1,3-dipolar cycloaddition reaction. The resulting graphene derivatives were employed for the immobilization of the nanoparticle precursor (Fe cations) at the introduced organic groups by a modified wet-impregnation method, followed by interaction with acetic acid vapours. The final graphene-iron oxide hybrid material was achieved by heating (calcination) in an inert atmosphere. Characterization by X-ray diffraction, transmission electron and atomic force microscopy, Raman and X-ray photoelectron spectroscopy gave evidence for the formation of rather small (<12 nm), spherical, magnetite-rich nanoparticles which were evenly distributed on the surface of few-layer (<1.2 nm thick) graphene. Due to the presence of the iron oxide nanoparticles, the hybrid material showed a superparamagnetic behaviour at room temperature.We report a facile approach for the in situ synthesis of very small iron oxide nanoparticles on the surface of high-quality graphene sheets. Our synthetic strategy involved the direct, liquid-phase exfoliation of highly crystalline graphite (avoiding any oxidation treatment) and the subsequent chemical functionalization of the graphene sheets via the well-established 1,3-dipolar cycloaddition reaction. The resulting graphene derivatives were employed for the immobilization of the nanoparticle precursor (Fe cations) at the introduced organic groups by a modified wet-impregnation method, followed by interaction with acetic acid vapours. The final graphene-iron oxide hybrid material was achieved by heating (calcination) in an inert atmosphere. Characterization by X-ray diffraction, transmission electron and atomic force microscopy, Raman and X-ray photoelectron spectroscopy gave evidence for the formation of rather small (<12 nm), spherical, magnetite-rich nanoparticles which were evenly distributed on the surface of few-layer (<1.2 nm thick) graphene. Due to the presence of the iron oxide nanoparticles, the hybrid material showed a superparamagnetic behaviour at room temperature. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr00765h

The effects of ion gun beam voltage on the electrical characteristics of NbCN/PbBi edge junctions

NASA Technical Reports Server (NTRS)

Lichtenberger, A. W.; Feldman, M. J.; Mattauch, R. J.; Cukauskas, E. J.

1989-01-01

The authors have succeeded in fabricating high-quality submicron NbCN edge junctions using a technique which is commonly used to make Nb edge junctions. A modified commercial ion gun was used to cut an edge in SiO2/NbCN films partially covered with photoresist. An insulating barrier was then formed on the exposed edge by reactive ion beam oxidation, and a counterelectrode of PbBi was deposited. The electrical quality of the resulting junctions was found to be strongly influenced by the ion beam acceleration voltages used to cut the edge and to oxidize it. For low ion beam voltages, the junction quality parameter was as high as Vm = 55 mV (measured at 3 mV), but higher ion beam voltages yielded strikingly poorer quality junctions. In light of the small coherence length of NbN, the dependence of the electrical characteristics on ion beam voltage is presumably due to mechanical damage of the NbCN surface. In contrast, for similar ion beam voltages, no such dependence was found for Nb edge junctions.

Modeling the Environmental Fate of Graphene Oxide and Its Phototransformation Products in Brier Creek Watershed Using the Water Quality Analysis Simulation Program 8 (WASP8)

EPA Science Inventory

The production of graphene-family nanoparticles (GFNs) appreciably increased in recent years. Among GFNs, graphene oxide (GO) is one of the most highly studied members due to its inexpensive synthesis cost compared to graphene, its stability in aqueous media and its broad applica...

Oxidation of Borneol to Camphor Using Oxone and Catalytic Sodium Chloride: A Green Experiment for the Undergraduate Organic Chemistry Laboratory

ERIC Educational Resources Information Center

Lang, Patrick T.; Harned, Andrew M.; Wissinger, Jane E.

2011-01-01

A new green oxidation procedure was developed for the undergraduate organic teaching laboratories using Oxone and a catalytic quantity of sodium chloride for the conversion of borneol to camphor. This simple 1 h, room temperature reaction afforded high quality and yield of product, was environmentally friendly, and produced negligible quantities…

Experimental Study of Floating-Gate-Type Metal-Oxide-Semiconductor Capacitors with Nanosize Triangular Cross-Sectional Tunnel Areas for Low Operating Voltage Flash Memory Application

NASA Astrophysics Data System (ADS)

Liu, Yongxun; Guo, Ruofeng; Kamei, Takahiro; Matsukawa, Takashi; Endo, Kazuhiko; O'uchi, Shinichi; Tsukada, Junichi; Yamauchi, Hiromi; Ishikawa, Yuki; Hayashida, Tetsuro; Sakamoto, Kunihiro; Ogura, Atsushi; Masahara, Meishoku

2012-06-01

The floating-gate (FG)-type metal-oxide-semiconductor (MOS) capacitors with planar (planar-MOS) and three-dimensional (3D) nanosize triangular cross-sectional tunnel areas (3D-MOS) have successfully been fabricated by introducing rapid thermal oxidation (RTO) and postdeposition annealing (PDA), and their electrical characteristics between the control gate (CG) and FG have been systematically compared. It was experimentally found in both planar- and 3D-MOS capacitors that the uniform and higher breakdown voltages are obtained by introducing RTO owing to the high-quality thermal oxide formation on the surface and etched edge regions of the n+ polycrystalline silicon (poly-Si) FG, and the leakage current is highly suppressed after PDA owing to the improved quality of the tetraethylorthosilicate (TEOS) silicon dioxide (SiO2) between CG and FG. Moreover, a lower breakdown voltage between CG and FG was obtained in the fabricated 3D-MOS capacitors as compared with that of planar-MOS capacitors thanks to the enhanced local electric field at the tips of triangular tunnel areas. The developed nanosize triangular cross-sectional tunnel area is useful for the fabrication of low operating voltage flash memories.

OC30 - Fracture reduction with nitrous oxide at the children's emergency department shortens the length of stay and reduces the use of full anaesthesia in the operating department.

PubMed

Lang, Sigrid; Wentzel, Anna-Pia; Ekstrom, Malin

2016-05-09

Theme: Accreditation and quality improvement. Dislocated fractures are common in the children's emergency department (ER). All forms of fracture reduction are very painful requiring nitrous oxide. The purpose is to shorten the length of stay in the hospital as well as sustain a high quality of care. All nurses received theoretical and practical training in the use of nitrous oxide. Evaluations with the families were made by telephone. A total of 40 enclosed fracture reductions were made at the ER, leading to a reduction of 33 patients in the operating department and the length of stay was shortened - this compared to the same time in 2014. No adverse event was reported and no patient felt any increase in pain during the treatment. All patients would repeat the procedure if necessary. The treatment has reduced the length of stay in the hospital without affecting the other patients in the ER or the quality of care.

A method to monitor the quality of ultra-thin nitride for trench DRAM with a buried strap structure

NASA Astrophysics Data System (ADS)

Wu, Yung-Hsien; Wang, Chun-Yao; Chang, Ian; Kao, Chien-Kang; Kuo, Chia-Ming; Ku, Alex

2007-02-01

A new approach to monitor the quality of an ultra-thin nitride film has been proposed. The nitride quality is monitored by observing the oxide thickness for the nitride film after wet oxidation since the resistance to oxidation strongly depends on its quality. To obtain a stable oxide thickness without interference from extrinsic factors for process monitoring, monitor wafers without dilute HF solution clean are suggested because the native-oxide containing surface is less sensitive to oxygen and therefore forms the nitride film with stable quality. In addition, the correlation between variable retention time (VRT) performance of a real dynamic random access memory (DRAM) product and oxide thickness from different nitride process temperatures can be successfully explained and this correlation can also be used to establish the appropriate oxide thickness range for process monitoring.

Tunable infrared absorption and visible transparency of colloidal aluminum-doped zinc oxide nanocrystals.

PubMed

Buonsanti, Raffaella; Llordes, Anna; Aloni, Shaul; Helms, Brett A; Milliron, Delia J

2011-11-09

Plasmonic nanocrystals have been attracting a lot of attention both for fundamental studies and different applications, from sensing to imaging and optoelectronic devices. Transparent conductive oxides represent an interesting class of plasmonic materials in addition to metals and vacancy-doped semiconductor quantum dots. Herein, we report a rational synthetic strategy of high-quality colloidal aluminum-doped zinc oxide nanocrystals. The presence of substitutional aluminum in the zinc oxide lattice accompanied by the generation of free electrons is proved for the first time by tunable surface plasmon absorption in the infrared region both in solution and in thin films.

Review of the Secondary National Ambient Air Quality Standard for Nitrogen Oxides, Sulfur Oxides and Particulate Matter: Risk and Exposure Assessment Planning Document

EPA Science Inventory

The U.S. Environmental Protection Agency (EPA) is conducting a review of the air quality criteria and the secondary (welfare-based) national ambient air quality standards (NAAQS) for nitrogen oxides (NOx), sulfur oxides (SOx), and particulate matter (PM). The major phases of the ...

Development of III-V p-MOSFETs with high-kappa gate stack for future CMOS applications

NASA Astrophysics Data System (ADS)

Nagaiah, Padmaja

As the semiconductor industry approaches the limits of traditional silicon CMOS scaling, non-silicon materials and new device architectures are gradually being introduced to improve Si integrated circuit performance and continue transistor scaling. Recently, the replacement of SiO2 with a high-k material (HfO2) as gate dielectric has essentially removed one of the biggest advantages of Si as channel material. As a result, alternate high mobility materials are being considered to replace Si in the channel to achieve higher drive currents and switching speeds. III-V materials in particular have become of great interest as channel materials, owing to their superior electron transport properties. However, there are several critical challenges that need to be addressed before III-V based CMOS can replace Si CMOS technology. Some of these challenges include development of a high quality, thermally stable gate dielectric/III-V interface, and improvement in III-V p-channel hole mobility to complement the n-channel mobility, low source/drain resistance and integration onto Si substrate. In this thesis, we would be addressing the first two issues i.e. the development high performance III-V p-channels and obtaining high quality III-V/high-k interface. We start with using the device architecture of the already established InGaAs n-channels as a baseline to understand the effect of remote scattering from the high-k oxide and oxide/semiconductor interface on channel transport properties such as electron mobility and channel electron concentration. Temperature dependent Hall electron mobility measurements were performed to separate various scattering induced mobility limiting factors. Dependence of channel mobility on proximity of the channel to the oxide interface, oxide thickness, annealing conditions are discussed. The results from this work will be used in the design of the p-channel MOSFETs. Following this, InxGa1-xAs (x>0.53) is chosen as channel material for developing p-channel MOSFETs. Band engineering, strain induced valence band splitting and quantum confinement is used to improve channel hole mobility. Experimental results on the Hall hole mobility is presented for InxGa1-xAs channels with varying In content, thickness of the quantum well and temperature. Then, high mobility InxGa 1-xAs heterostructure thus obtained are integrated with in-situ deposited high-k gate oxide required for high performance p-MOSFET and discuss the challenges associated with the gated structure and draw conclusions on this material system. Antimonide based channel materials such as GaSb and InxGa 1-xSb are explored for III-V based p-MOSFETs in last two chapters. Options for Sb based strained QW channels to obtain maximum hole mobility by varying the strain, channel and barrier material, thickness of the layers etc. is discussed followed by the growth of these Sb channels on GaAs and InP substrates using molecular beam epitaxy. The physical properties of the structures such as the heterostructure quality, alloy content and surface roughness are examined via TEM, XRD and AFM. Following this, electrical measurement results on Hall hole mobility is presented. The effect of strain, alloy content, temperature and thickness on channel mobility and concentration is reported. Development of GaSb n- and p-MOS capacitor structures with in-situ deposited HfO2 gate oxide dielectric using in-situ deposited amorphous Si (a-Si) interface passivation layer (IPL) to improve the interface quality of high-k oxide and (In)GaSb surface is presented. In-situ deposited gate oxides such as Al2O3 and combination oxide of Al 2O3 and HfO2 with and without the a-Si IPL are also explored as alternate gate dielectrics. Subsequently, MOS capacitor structures using buried InGaSb QWs are demonstrated. Development of an inversion type bulk GaSb with implanted source-drain contacts and in-situ deposited gate oxide HfO2 gate oxide is discussed. The merits of biaxial compressive strain is demonstrated on strained surface and buried channel In0.36 Ga0.64Sb QW MOSFETs with thin top barrier and in-situ deposited a-Si IPL and high-k HfO2 as well as combination Al 2O3+HfO2 gate stacks and ex-situ atomic layer deposited (ALD) combination gate oxide and with thin 2 nm InAs surface passivation layer is presented. Finally, summary of the salient results from the different chapters is provided with recommendations for future research.

Interface Physics in Complex Oxide Heterostructures

NASA Astrophysics Data System (ADS)

Zubko, Pavlo; Gariglio, Stefano; Gabay, Marc; Ghosez, Philippe; Triscone, Jean-Marc

2011-03-01

Complex transition metal oxides span a wide range of crystalline structures and play host to an incredible variety of physical phenomena. High dielectric permittivities, piezo-, pyro-, and ferroelectricity are just a few of the functionalities offered by this class of materials, while the potential for applications of the more exotic properties like high temperature superconductivity and colossal magnetoresistance is still waiting to be fully exploited. With recent advances in deposition techniques, the structural quality of oxide heterostructures now rivals that of the best conventional semiconductors, taking oxide electronics to a new level. Such heterostructures have enabled the fabrication of artificial multifunctional materials. At the same time they have exposed a wealth of phenomena at the boundaries where compounds with different structural instabilities and electronic properties meet, giving unprecedented access to new physics emerging at oxide interfaces. Here we highlight some of these exciting new interface phenomena.

Atomic-Scale Characterization of Oxide Interfaces and Superlattices Using Scanning Transmission Electron Microscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Spurgeon, Steven R.; Chambers, Scott A.

Scanning transmission electron microscopy (STEM) has become one of the fundamental tools to characterize oxide interfaces and superlattices. Atomic-scale structure, chemistry, and composition mapping can now be conducted on a wide variety of materials systems thanks to the development of aberration-correctors and advanced detectors. STEM imaging and diffraction, coupled with electron energy loss (EELS) and energy-dispersive X-ray (EDS) spectroscopies, offer unparalleled, high-resolution analysis of structure-property relationships. In this chapter we highlight investigations into key phenomena, including interfacial conductivity in oxide superlattices, charge screening effects in magnetoelectric heterostructures, the design of high-quality iron oxide interfaces, and the complex physics governing atomic-scalemore » chemical mapping. These studies illustrate how unique insights from STEM characterization can be integrated with other techniques and first-principles calculations to develop better models for the behavior of functional oxides.« less

Pulsed photonic fabrication of nanostructured metal oxide thin films

NASA Astrophysics Data System (ADS)

Bourgeois, Briley B.; Luo, Sijun; Riggs, Brian C.; Adireddy, Shiva; Chrisey, Douglas B.

2017-09-01

Nanostructured metal oxide thin films with a large specific surface area are preferable for practical device applications in energy conversion and storage. Herein, we report instantaneous (milliseconds) photonic synthesis of three-dimensional (3-D) nanostructured metal oxide thin films through the pulsed photoinitiated pyrolysis of organometallic precursor films made by chemical solution deposition. High wall-plug efficiency-pulsed photonic irradiation (xenon flash lamp, pulse width of 1.93 ms, fluence of 7.7 J/cm2 and frequency of 1.2 Hz) is used for scalable photonic processing. The photothermal effect of subsequent pulses rapidly improves the crystalline quality of nanocrystalline metal oxide thin films in minutes. The following paper highlights pulsed photonic fabrication of 3-D nanostructured TiO2, Co3O4, and Fe2O3 thin films, exemplifying a promising new method for the low-cost and high-throughput manufacturing of nanostructured metal oxide thin films for energy applications.

Spatio-temporal variation in territory quality and oxidative status: a natural experiment in the Seychelles warbler (Acrocephalus sechellensis)

PubMed Central

van de Crommenacker, Janske; Komdeur, Jan; Burke, Terry; Richardson, David S

2011-01-01

1.Fluctuations in the quality of the habitat in which an animal lives can have major consequences for its behaviour and physiological state. In poor-quality habitat with low food availability, metabolically intensive foraging activity is likely to result in increased generation of reactive oxygen species, while scarcity of food can lead to a weakening of exogenously derived antioxidant defences. The consequent oxidant/antioxidant imbalance may lead to elevated oxidative stress. 2.Although the link between food availability and oxidative stress has been studied in the laboratory, very little is known about this relationship in the wild. Here, we investigate the association between territory quality (measured through food availability) and oxidative stress in the Seychelles warbler (Acrocephalus sechellensis). 3.Seychelles warblers are insectivorous birds that inhabit a fixed feeding territory year round. Individuals experience profound and rapid local fluctuations in territory quality within these territories, owing to changing patterns of vegetation defoliation resulting from seasonal changes in prevailing wind direction and wind-borne salt spray. 4.As expected, oxidant generation (measured as reactive oxygen metabolites; ROMs) was higher when territory quality was low, but there was no correlation between territory quality and antioxidant capacity (OXY). The negative correlation between territory quality and ROMs was significant between individuals and approached significance within individuals, indicating that the pattern resulted from individual responses to environmental variation. 5.ROMs and OXY levels within individuals were positively correlated, but the relationship between territory quality and ROMs persisted after including OXY as a covariate, implying that oxidative stress occurs in low territory quality conditions. 6.Our results indicate that the oxidative stress balance of an individual is sensitive to relatively short-term changes in territory quality, which may have consequences for the birds’ fitness. PMID:21198588

Effect of nano packaging on preservation quality of Nanjing 9108 rice variety at high temperature and humidity.

PubMed

Wang, Fan; Hu, Qiuhui; Mugambi Mariga, Alfred; Cao, Chongjiang; Yang, Wenjian

2018-01-15

A nano packaging material containing nano Ag, nano TiO 2 , nano attapulgite and SiO 2 was prepared, and its impact on quality of Nanjing 9108 rice at 37°C and 85% relative humidity was studied. Effects of the packaging on ambient gases and chromatic aberration of rice were determined. Moreover, oxidation level, molds growth and flavor of rice were also analyzed. Results showed that nano packaging material had antimicrobial effects and maintained low O 2 and high CO 2 content in the packages. The packages thereby inhibited the growth of molds and the production of fatty acids, restrained the increase of lipase activity, and reduced the oxidation of fats and proteins. As a result, the production of yellow and white-belly rice were inhibited. Furthermore, the color and flavor of rice were maintained. Therefore, the nano-packing material could be applied for preservation of rice to improve preservation quality. Copyright © 2017 Elsevier Ltd. All rights reserved.

Protein Oxidation and Sensory Quality of Brine-Injected Pork Loins Added Ascorbate or Extracts of Green Tea or Maté during Chill-Storage in High-Oxygen Modified Atmosphere

PubMed Central

Tørngren, Mari Ann

2018-01-01

Background: Ascorbate is often applied to enhance stability and robustness of brine-injected pork chops sold for retail, but may affect protein oxidation, while plant extracts are potential substitutes. Methods: Brine-injected pork chops (weight-gain ~12%, NaCl ~0.9%) prepared with ascorbate (225 ppm), green tea extract (25 ppm gallic acid equivalents (GAE)), or maté extract (25 ppm GAE) stored (5 °C, seven days) in high-oxygen atmosphere packaging (MAP: 80% O2 and 20% CO2) were analyzed for color changes, sensory quality, and protein oxidation compared to a control without antioxidant. Results: No significant differences were observed for green tea and maté extracts as compared to ascorbate when evaluated based on lipid oxidation derived off-flavors, except for stale flavor, which maté significantly reduced. All treatments increased the level of the protein oxidation product, α-aminoadipic semialdehyde as compared to the control, and ascorbate was further found to increase thiol loss and protein cross-linking, with a concomitant decrease in the sensory perceived tenderness. Conclusions: Green tea and maté were found to equally protect against lipid oxidation derived off-flavors, and maté showed less prooxidative activity towards proteins as compared to ascorbate, resulting in more tender meat. Maté is a valuable substitute for ascorbate in brine-injected pork chops. PMID:29342928

Effect of friction on oxidative graphite intercalation and high-quality graphene formation.

PubMed

Seiler, Steffen; Halbig, Christian E; Grote, Fabian; Rietsch, Philipp; Börrnert, Felix; Kaiser, Ute; Meyer, Bernd; Eigler, Siegfried

2018-02-26

Oxidative wet-chemical delamination of graphene from graphite is expected to become a scalable production method. However, the formation process of the intermediate stage-1 graphite sulfate by sulfuric acid intercalation and its subsequent oxidation are poorly understood and lattice defect formation must be avoided. Here, we demonstrate film formation of micrometer-sized graphene flakes with lattice defects down to 0.02% and visualize the carbon lattice by transmission electron microscopy at atomic resolution. Interestingly, we find that only well-ordered, highly crystalline graphite delaminates into oxo-functionalized graphene, whereas other graphite grades do not form a proper stage-1 intercalate and revert back to graphite upon hydrolysis. Ab initio molecular dynamics simulations show that ideal stacking and electronic oxidation of the graphite layers significantly reduce the friction of the moving sulfuric acid molecules, thereby facilitating intercalation. Furthermore, the evaluation of the stability of oxo-species in graphite sulfate supports an oxidation mechanism that obviates intercalation of the oxidant.

Non-activated high surface area expanded graphite oxide for supercapacitors

NASA Astrophysics Data System (ADS)

Vermisoglou, E. C.; Giannakopoulou, T.; Romanos, G. E.; Boukos, N.; Giannouri, M.; Lei, C.; Lekakou, C.; Trapalis, C.

2015-12-01

Microwave irradiation of graphite oxide constitutes a facile route toward production of reduced graphene oxide, since during this treatment both exfoliation and reduction of graphite oxide occurs. In this work, the effect of pristine graphite (type, size of flakes), pretreatment and oxidation cycles on the finally produced expanded material was examined. All the types of graphite that were tested afforded materials with high BET surface areas ranging from 940 m2/g to 2490 m2/g, without intervening an activation stage at elevated temperature. SEM and TEM images displayed exfoliated structures, where the flakes were significantly detached and curved. The quality of the reduced graphene oxide sheets was evidenced both by X-ray photoelectron spectroscopy and Raman spectroscopy. The electrode material capacitance was determined via electrochemical impedance spectroscopy and cyclic voltammetry. The materials with PEDOT binder had better performance (∼97 F/g) at low operation rates while those with PVDF binder performed better (∼20 F/g) at higher rates, opening up perspectives for their application in supercapacitors.

High-Quality Draft Genomes from Thermus caliditerrae YIM 77777 and T. tengchongensis YIM 77401, Isolates from Tengchong, China

DOE PAGES

Mefferd, Chrisabelle C.; Zhou, En-Min; Yu, Tian-Tian; ...

2016-04-28

The draft genomes ofThermus  tengchongensisYIM 77401 andT. caliditerraeYIM 77777 are 2,562,314 and 2,218,114 bp and encode 2,726 and 2,305 predicted genes, respectively. Gene content and growth experiments demonstrate broad metabolic capacity, including starch hydrolysis, thiosulfate oxidation, arsenite oxidation, incomplete denitrification, and polysulfide reduction.

Self-Functionalization Behind a Solution-Processed NiOx Film Used As Hole Transporting Layer for Efficient Perovskite Solar Cells.

PubMed

Ciro, John; Ramírez, Daniel; Mejía Escobar, Mario Alejandro; Montoya, Juan Felipe; Mesa, Santiago; Betancur, Rafael; Jaramillo, Franklin

2017-04-12

Fabrication of solution-processed perovskite solar cells (PSCs) requires the deposition of high quality films from precursor inks. Frequently, buffer layers of PSCs are formed from dispersions of metal oxide nanoparticles (NPs). Therefore, the development of trustable methods for the preparation of stable colloidal NPs dispersions is crucial. In this work, a novel approach to form very compact semiconducting buffer layers with suitable optoelectronic properties is presented through a self-functionalization process of the nanocrystalline particles by their own amorphous phase and without adding any other inorganic or organic functionalization component or surfactant. Such interconnecting amorphous phase composed by residual nitrate, hydroxide, and sodium ions, proved to be fundamental to reach stable colloidal dispersions and contribute to assemble the separate crystalline nickel oxide NPs in the final film, resulting in a very homogeneous and compact layer. A proposed mechanism behind the great stabilization of the nanoparticles is exposed. At the end, the self-functionalized nickel oxide layer exhibited high optoelectronic properties enabling perovskite p-i-n solar cells as efficient as 16.6% demonstrating the pertinence of the presented strategy to obtain high quality buffer layers processed in solution at room temperature.

Influence of high inorganic selenium and manganese diets for fattening pigs on oxidative stability and pork quality parameters.

PubMed

Schwarz, C; Ebner, K M; Furtner, F; Duller, S; Wetscherek, W; Wernert, W; Kandler, W; Schedle, K

2017-02-01

Data are scarce regarding combined high Se and Mn supplementation in livestock diets, however, as Se and Mn are functionally related as cofactors of glutathione peroxidase (GPx) and Mn-superoxide dismutase (SOD), respectively, beneficial synergistic effects on oxidative stability of tissues may result. This experiment evaluated the effect of an oversupply of Se and Mn within European legal limits compared with recommendations on performance, oxidative stability of the organism and meat quality in a randomised complete block design. A total of 60 crossbred gilts were fed maize-barley-soya bean meal diets formulated in a 2×2 factorial approach with inorganic Se (0.2 v. 0.5 mg/kg Se dry matter (DM)) or inorganic Mn (20 v. 150 mg/kg Mn DM) from 31 to 116 kg BW. Se supplementation reduced feed intake, whereas high Mn diets impaired average daily gain (P<0.05). Qualitative carcass characteristics were impaired by Se and Mn predominantly in the semimembranosus muscle. Activity of GPx in liver was increased by high Se diets (P<0.05). Mn supplementation increased catalase (CAT) activity in liver, GPx in plasma and total antioxidative capacity (TAC) in muscle, whereas it decreased CAT activity in plasma (P<0.05). Cu/Zn-SOD in muscle showed higher activity in high-Se-low-Mn diets but lower activity when both high Se and Mn were combined (Se×Mn P<0.05). Mn supplementation increased Mn concentration in longissimus thoracis et lumborum, but simultaneously reduced Se concentration (P<0.05). Upon retail display, Mn increased lipid oxidation more pronouncedly (higher thiobarbituric acid reactive substances; P<0.05) than Se (P<0.10). Despite some positive effects (Mn increased TAC, Se increased GPx, Se and Mn increased tenderness), no synergistic effects of high Se and Mn diets or an overall beneficial impact on meat quality, especially during storage, could be observed. Including the negative effects on performance, feeding Se and Mn up to the maximum legal level cannot be recommended.

Adult exercise effects on oxidative stress and reproductive programming in male offspring of obese rats.

PubMed

Santos, Mery; Rodríguez-González, Guadalupe L; Ibáñez, Carlos; Vega, Claudia C; Nathanielsz, Peter W; Zambrano, Elena

2015-02-01

Exercise improves health but few data are available regarding benefits of exercise in offspring exposed to developmental programming. There is currently a worldwide epidemic of obesity. Obesity in pregnant women predisposes offspring to obesity. Maternal obesity has well documented effects on offspring reproduction. Few studies address ability of offspring exercise to reduce adverse outcomes. We observed increased oxidative stress and impaired sperm function in rat offspring of obese mothers. We hypothesized that regular offspring exercise reverses adverse effects of maternal obesity on offspring sperm quality and fertility. Female Wistar rats ate chow (C) or high-energy, obesogenic diet (MO) from weaning through lactation, bred at postnatal day (PND) 120, and ate their pregnancy diet until weaning. All offspring ate C diet from weaning. Five male offspring (different litters) ran on a wheel for 15 min, 5 times/week from PND 330 to 450 and were euthanized at PND 450. Average distance run per session was lower in MO offspring who had higher body weight, adiposity index, and gonadal fat and showed increases in testicular oxidative stress biomarkers. Sperm from MO offspring had reduced antioxidant enzyme activity, lower sperm quality, and fertility. Exercise in MO offspring decreased testicular oxidative stress, increased sperm antioxidant activity and sperm quality, and improved fertility. Exercise intervention has beneficial effects on adiposity index, gonadal fat, oxidative stress markers, sperm quality, and fertility. Thus regular physical exercise in male MO offspring recuperates key male reproductive functions even at advanced age: it's never too late. Copyright © 2015 the American Physiological Society.

Effect of Time and Deposition Method on Quality of Phosphonic Acid Modifier Self-Assembled Monolayers on Indium Zinc Oxide

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sang, Lingzi; Knesting, Kristina M.; Bulusu, Anuradha

Phosphonic acid (PA) self-assembled monolayers (SAMs) are utilized at critical interfaces between transparent conductive oxides (TCO) and organic active layers in organic photovoltaic devices (OPVs). The effects of PA deposition method and time on the formation of close-packed, high-quality monolayers is investigated here for SAMs fabricated by solution deposition, micro-contact printing, and spray coating. The solution deposition isotherm for pentafluorinated benzylphosphonic acid (F5BnPA) on indium-doped zinc oxide (IZO) is studied using polarization modulation-infrared reflection-absorption spectroscopy (PM-IRRAS) at room temperature as a model PA/IZO system. Fast surface adsorption occurs within the first min; however, well-oriented high-quality SAMs are reached only aftermore » -48 h, presumably through a continual process of molecular adsorption/desorption and monolayer filling accompanied by molecular reorientation. Two other rapid, soak-free deposition techniques, micro-contact printing and spray coating, are also explored. SAM quality is compared for deposition of phenyl phosphonic acid (PPA), F13-octylphosphonic acid (F13OPA), and pentafluorinated benzyl phosphonic acid (F5BnPA) by solution deposition, micro-contact printing and spray coating using PM-IRRAS. In contrast to micro-contact printing and spray coating techniques, 48-168 h solution deposition at both room temperature and 70 degrees C result in contamination- and surface etch-free close-packed monolayers with good reproducibility. SAMs fabricated by micro-contact printing and spray coating are much less well ordered.« less

Inflammation, Oxidative Stress, and Antioxidants Contribute to Selected Sleep Quality and Cardiometabolic Health Relationships: A Cross-Sectional Study.

PubMed

Kanagasabai, Thirumagal; Ardern, Chris I

2015-01-01

Sleep is vital for cardiometabolic health, but a societal shift toward poor sleep is a prominent feature of many modern cultures. Concurrently, factors such as diet and lifestyle have also changed and may mediate the relationship between sleep quality and cardiometabolic health. Objectives were to explore (1) the interrelationship and (2) mediating effect of inflammation, oxidative stress, and antioxidants on sleep quality and cardiometabolic health. Cross-sectional data from the US National Health and Nutritional Examination Survey 2005-06 (≥20 y; N = 2,072) was used. Cardiometabolic health was defined as per the Joint Interim Statement; overall sleep quality was determined from six sleep habits and categorized as good, fair, poor, and very poor. Fair quality sleepers had optimal inflammation, oxidative stress, and antioxidant levels. Inflammation was above the current clinical reference range across all sleep quality categories, while oxidative stress was only within the clinical reference range for fair sleep quality. Selected sleep quality-cardiometabolic health relationships were mediated by inflammation, oxidative stress, and antioxidants and were moderated by sex. Our results provide initial evidence of a potential role for inflammation, oxidative stress, and antioxidants in the pathway between poor sleep quality-cardiometabolic decline. Further prospective research is needed to confirm our results.

Bulk and Thin Film Synthesis of Compositionally Variant Entropy-stabilized Oxides.

PubMed

Sivakumar, Sai; Zwier, Elizabeth; Meisenheimer, Peter Benjamin; Heron, John T

2018-05-29

Here, we present a procedure for the synthesis of bulk and thin film multicomponent (Mg0.25(1-x)CoxNi0.25(1-x)Cu0.25(1-x)Zn0.25(1-x))O (Co variant) and (Mg0.25(1-x)Co0.25(1-x)Ni0.25(1-x)CuxZn0.25(1-x))O (Cu variant) entropy-stabilized oxides. Phase pure and chemically homogeneous (Mg0.25(1-x)CoxNi0.25(1-x)Cu0.25(1-x)Zn0.25(1-x))O (x = 0.20, 0.27, 0.33) and (Mg0.25(1-x)Co0.25(1-x)Ni0.25(1-x)CuxZn0.25(1-x))O (x = 0.11, 0.27) ceramic pellets are synthesized and used in the deposition of ultra-high quality, phase pure, single crystalline thin films of the target stoichiometry. A detailed methodology for the deposition of smooth, chemically homogeneous, entropy-stabilized oxide thin films by pulsed laser deposition on (001)-oriented MgO substrates is described. The phase and crystallinity of bulk and thin film materials are confirmed using X-ray diffraction. Composition and chemical homogeneity are confirmed by X-ray photoelectron spectroscopy and energy dispersive X-ray spectroscopy. The surface topography of thin films is measured with scanning probe microscopy. The synthesis of high quality, single crystalline, entropy-stabilized oxide thin films enables the study of interface, size, strain, and disorder effects on the properties in this new class of highly disordered oxide materials.

Performance characterization of water recovery and water quality from chemical/organic waste products

NASA Technical Reports Server (NTRS)

Moses, W. M.; Rogers, T. D.; Chowdhury, H.; Cullingford, H. S.

1989-01-01

The water reclamation subsystems currently being evaluated for the Space Shuttle Freedom are briefly reviewed with emphasis on a waste water management system capable of processing wastes containing high concentrations of organic/inorganic materials. The process combines low temperature/pressure to vaporize water with high temperature catalytic oxidation to decompose volatile organics. The reclaimed water is of potable quality and has high potential for maintenance under sterile conditions. Results from preliminary experiments and modifications in process and equipment required to control reliability and repeatability of system operation are presented.

Storing red blood cells with vitamin C and N-acetylcysteine prevents oxidative stress-related lesions: a metabolomics overview.

PubMed

Pallotta, Valeria; Gevi, Federica; D'alessandro, Angelo; Zolla, Lello

2014-07-01

Recent advances in red blood cell metabolomics have paved the way for further improvements of storage solutions. In the present study, we exploited a validated high performance liquid chromatography-mass spectrometry analytical workflow to determine the effects of vitamin C and N-acetylcysteine supplementation (anti-oxidants) on the metabolome of erythrocytes stored in citrate-phosphate-dextrose saline-adenine-glucose-mannitol medium under blood bank conditions. We observed decreased energy metabolism fluxes (glycolysis and pentose phosphate pathway). A tentative explanation of this phenomenon could be related to the observed depression of the uptake of glucose, since glucose and ascorbate are known to compete for the same transporter. Anti-oxidant supplementation was effective in modulating the redox poise, through the promotion of glutathione homeostasis, which resulted in decreased haemolysis and less accumulation of malondialdehyde and oxidation by-products (including oxidized glutathione and prostaglandins). Anti-oxidants improved storage quality by coping with oxidative stress at the expense of glycolytic metabolism, although reservoirs of high energy phosphate compounds were preserved by reduced cyclic AMP-mediated release of ATP.

High-efficiency solar cells fabricated from direct-current magnetron sputtered n-indium tin oxide onto p-InP grown by atmospheric pressure metalorganic vapor phase epitaxy

NASA Technical Reports Server (NTRS)

Li, X.; Wanlass, M. W.; Gessert, T. A.; Emery, K. A.; Coutts, T. J.

1989-01-01

An attempt is made to improve device efficiencies by depositing indium tin oxide onto epitaxially grown p-InP on p(+)-InP substrates. This leads to a reduction in the device series resistance, high-quality reproducible surfaces, and an improvement in the transport properties of the base layer. Moreover, many of the facets associated with badly characterized bulk liquid encapsulated Czochralski substrates used in previous investigations are removed in this way.

Epitaxial ferromagnetic oxide thin films on silicon with atomically sharp interfaces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Coux, P. de; CEMES-CNRS, 29 rue Jeanne Marvig, BP 94347, Toulouse Cedex 4; Bachelet, R.

A bottleneck in the integration of functional oxides with silicon, either directly grown or using a buffer, is the usual formation of an amorphous interfacial layer. Here, we demonstrate that ferromagnetic CoFe{sub 2}O{sub 4} films can be grown epitaxially on Si(111) using a Y{sub 2}O{sub 3} buffer layer, and remarkably the Y{sub 2}O{sub 3}/Si(111) interface is stable and remains atomically sharp. CoFe{sub 2}O{sub 4} films present high crystal quality and high saturation magnetization.

Electro-deposition of superconductor oxide films

DOEpatents

Bhattacharya, Raghu N.

2001-01-01

Methods for preparing high quality superconducting oxide precursors which are well suited for further oxidation and annealing to form superconducting oxide films. The method comprises forming a multilayered superconducting precursor on a substrate by providing an electrodeposition bath comprising an electrolyte medium and a substrate electrode, and providing to the bath a plurality of precursor metal salts which are capable of exhibiting superconducting properties upon subsequent treatment. The superconducting precursor is then formed by electrodepositing a first electrodeposited (ED) layer onto the substrate electrode, followed by depositing a layer of silver onto the first electrodeposited (ED) layer, and then electrodepositing a second electrodeposited (ED) layer onto the Ag layer. The multilayered superconducting precursor is suitable for oxidation at a sufficient annealing temperature in air or an oxygen-containing atmosphere to form a crystalline superconducting oxide film.

Comparative Evaluation of Diagnostic Tools for Oxidative Deterioration of Polyunsaturated Fatty Acid-Enriched Infant Formulas during Storage

PubMed Central

Siefarth, Caroline; Serfert, Yvonne; Drusch, Stephan; Buettner, Andrea

2013-01-01

The challenge in the development of infant formulas enriched with polyunsaturated fatty acids (PUFAs) is to meet the consumers’ expectations with regard to high nutritional and sensory value. In particular, PUFAs may be prone to fatty acid oxidation that can generate potential rancid, metallic and/or fishy off-flavors. Although such off-flavors pose no health risk, they can nevertheless lead to rejection of products by consumers. Thus, monitoring autoxidation at its early stages is of great importance and finding a suitable analytical tool to perform these evaluations is therefore of high interest in quality monitoring. Two formulations of infant formulas were varied systematically in their mineral composition and their presence of antioxidants to produce 18 model formulas. All models were aged under controlled conditions and their oxidative deterioration was monitored. A quantitative study was performed on seven characteristic odor-active secondary oxidation products in the formulations via two-dimensional high resolution gas chromatography-mass spectrometry/olfactometry (2D-HRGC-MS/O). The sensitivity of the multi-dimensional GC-MS/O analysis was supported by two additional analytical tools for monitoring autoxidation, namely the analysis of lipid hydroperoxides and conjugated dienes. Furthermore, an aroma profile analysis (APA) was performed to reveal the presence and intensities of typical odor qualities generated in the course of fatty acid oxidation. The photometrical analyses of lipid hydroperoxides and conjugated dienes were found to be too insensitive for early indication of the development of sensory defects. By comparison, the 2D-HRGC-MS/O was capable of monitoring peroxidation of PUFAs at low ppb-level in its early stages. Thereby, it was possible to screen oxidative variances on the basis of such volatile markers already within eight weeks after production of the products, which is an earlier indication of oxidative deterioration than achievable via conventional methods. In detail, oxidative variances between the formulations revealed that lipid oxidation was low when copper was administered in an encapsulated form and when antioxidants (vitamin E, ascorbyl palmitate) were present. PMID:28234303

Controlled Synthesis of Atomically Layered Hexagonal Boron Nitride via Chemical Vapor Deposition.

PubMed

Liu, Juanjuan; Kutty, R Govindan; Liu, Zheng

2016-11-29

Hexagonal boron nitrite (h-BN) is an attractive material for many applications including electronics as a complement to graphene, anti-oxidation coatings, light emitters, etc. However, the synthesis of high-quality h-BN is still a great challenge. In this work, via controlled chemical vapor deposition, we demonstrate the synthesis of h-BN films with a controlled thickness down to atomic layers. The quality of as-grown h-BN is confirmed by complementary characterizations including high-resolution transition electron microscopy, atomic force microscopy, Raman spectroscopy and X-ray photo-electron spectroscopy. This work will pave the way for production of large-scale and high-quality h-BN and its applications as well.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Ao; Liu, Guoxia, E-mail: gxliu@qdu.edu.cn, E-mail: fukaishan@yahoo.com; Zhu, Huihui

Solution-processed p-type oxide semiconductors have recently attracted increasing interests for the applications in low-cost optoelectronic devices and low-power consumption complementary metal-oxide-semiconductor circuits. In this work, p-type nickel oxide (NiO{sub x}) thin films were prepared using low-temperature solution process and integrated as the channel layer in thin-film transistors (TFTs). The electrical properties of NiO{sub x} TFTs, together with the characteristics of NiO{sub x} thin films, were systematically investigated as a function of annealing temperature. By introducing aqueous high-k aluminum oxide (Al{sub 2}O{sub 3}) gate dielectric, the electrical performance of NiO{sub x} TFT was improved significantly compared with those based on SiO{submore » 2} dielectric. Particularly, the hole mobility was found to be 60 times enhancement, quantitatively from 0.07 to 4.4 cm{sup 2}/V s, which is mainly beneficial from the high areal capacitance of the Al{sub 2}O{sub 3} dielectric and high-quality NiO{sub x}/Al{sub 2}O{sub 3} interface. This simple solution-based method for producing p-type oxide TFTs is promising for next-generation oxide-based electronic applications.« less

Spatio-temporal variation in territory quality and oxidative status: a natural experiment in the Seychelles warbler (Acrocephalus sechellensis).

PubMed

van de Crommenacker, Janske; Komdeur, Jan; Burke, Terry; Richardson, David S

2011-05-01

1. Fluctuations in the quality of the habitat in which an animal lives can have major consequences for its behaviour and physiological state. In poor-quality habitat with low food availability, metabolically intensive foraging activity is likely to result in increased generation of reactive oxygen species, while scarcity of food can lead to a weakening of exogenously derived antioxidant defences. The consequent oxidant/antioxidant imbalance may lead to elevated oxidative stress. 2. Although the link between food availability and oxidative stress has been studied in the laboratory, very little is known about this relationship in the wild. Here, we investigate the association between territory quality (measured through food availability) and oxidative stress in the Seychelles warbler (Acrocephalus sechellensis). 3. Seychelles warblers are insectivorous birds that inhabit a fixed feeding territory year round. Individuals experience profound and rapid local fluctuations in territory quality within these territories, owing to changing patterns of vegetation defoliation resulting from seasonal changes in prevailing wind direction and wind-borne salt spray. 4. As expected, oxidant generation (measured as reactive oxygen metabolites; ROMs) was higher when territory quality was low, but there was no correlation between territory quality and antioxidant capacity (OXY). The negative correlation between territory quality and ROMs was significant between individuals and approached significance within individuals, indicating that the pattern resulted from individual responses to environmental variation. 5. ROMs and OXY levels within individuals were positively correlated, but the relationship between territory quality and ROMs persisted after including OXY as a covariate, implying that oxidative stress occurs in low territory quality conditions. 6. Our results indicate that the oxidative stress balance of an individual is sensitive to relatively short-term changes in territory quality, which may have consequences for the birds' fitness. © 2011 The Authors. Journal of Animal Ecology © 2011 British Ecological Society.

78 FR 54813 - Approval and Promulgation of Air Quality Implementation Plans; Maine; Oxides of Nitrogen...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-09-06

... ENVIRONMENTAL PROTECTION AGENCY 40 CFR Parts 52 [EPA-R01-OAR-2012-0895; FRL- 9900-85-Region1] Approval and Promulgation of Air Quality Implementation Plans; Maine; Oxides of Nitrogen Exemption and... proposed Approval and Promulgation of Air Quality Implementation Plans; Maine; Oxides of Nitrogen Exemption...

Unexpected increase in the oxidation capacity of the urban atmosphere of Madrid, Spain.

PubMed

Saiz-Lopez, A; Borge, R; Notario, A; Adame, J A; Paz, D de la; Querol, X; Artíñano, B; Gómez-Moreno, F J; Cuevas, C A

2017-04-11

Atmospheric oxidants such as ozone (O 3 ), hydroxyl and nitrate radicals (OH and NO 3 ) determine the ability of the urban atmosphere to process organic and inorganic pollutants, which have an impact on air quality, environmental health and climate. Madrid city has experienced an increase of 30-40% in ambient air O 3 levels, along with a decrease of 20-40% in NO 2 , from 2007 to 2014. Using air pollution observations and a high-resolution air quality model, we find a large concentration increase of up to 70% and 90% in OH and NO 3 , respectively, in downtown Madrid (domain-wide average increase of 10% and 32% for OH and NO 3 , respectively). The results also show an 11% reduction in the nitric acid concentrations, leading to a remarkable denoxification of this urban atmosphere with implications for lower PM 2.5 levels and nitrogen input into ecosystems. This study suggests that projected worldwide NO x emission reductions, following air quality standards, will lead to important changes in the oxidizing capacity of the atmosphere in and around large cities.

Unexpected increase in the oxidation capacity of the urban atmosphere of Madrid, Spain

NASA Astrophysics Data System (ADS)

Saiz-Lopez, A.; Borge, R.; Notario, A.; Adame, J. A.; Paz, D. De La; Querol, X.; Artíñano, B.; Gómez-Moreno, F. J.; Cuevas, C. A.

2017-04-01

Atmospheric oxidants such as ozone (O3), hydroxyl and nitrate radicals (OH and NO3) determine the ability of the urban atmosphere to process organic and inorganic pollutants, which have an impact on air quality, environmental health and climate. Madrid city has experienced an increase of 30-40% in ambient air O3 levels, along with a decrease of 20-40% in NO2, from 2007 to 2014. Using air pollution observations and a high-resolution air quality model, we find a large concentration increase of up to 70% and 90% in OH and NO3, respectively, in downtown Madrid (domain-wide average increase of 10% and 32% for OH and NO3, respectively). The results also show an 11% reduction in the nitric acid concentrations, leading to a remarkable denoxification of this urban atmosphere with implications for lower PM2.5 levels and nitrogen input into ecosystems. This study suggests that projected worldwide NOx emission reductions, following air quality standards, will lead to important changes in the oxidizing capacity of the atmosphere in and around large cities.

Unexpected increase in the oxidation capacity of the urban atmosphere of Madrid, Spain

PubMed Central

Saiz-Lopez, A.; Borge, R.; Notario, A.; Adame, J. A.; Paz, D. de la; Querol, X.; Artíñano, B.; Gómez-Moreno, F. J.; Cuevas, C. A.

2017-01-01

Atmospheric oxidants such as ozone (O3), hydroxyl and nitrate radicals (OH and NO3) determine the ability of the urban atmosphere to process organic and inorganic pollutants, which have an impact on air quality, environmental health and climate. Madrid city has experienced an increase of 30–40% in ambient air O3 levels, along with a decrease of 20–40% in NO2, from 2007 to 2014. Using air pollution observations and a high-resolution air quality model, we find a large concentration increase of up to 70% and 90% in OH and NO3, respectively, in downtown Madrid (domain-wide average increase of 10% and 32% for OH and NO3, respectively). The results also show an 11% reduction in the nitric acid concentrations, leading to a remarkable denoxification of this urban atmosphere with implications for lower PM2.5 levels and nitrogen input into ecosystems. This study suggests that projected worldwide NOx emission reductions, following air quality standards, will lead to important changes in the oxidizing capacity of the atmosphere in and around large cities. PMID:28397785

Reactive nitrogen oxides in the southeast United States national parks: source identification, origin, and process budget

NASA Astrophysics Data System (ADS)

Tong, Daniel Quansong; Kang, Daiwen; Aneja, Viney P.; Ray, John D.

2005-01-01

We present in this study both measurement-based and modeling analyses for elucidation of source attribution, influence areas, and process budget of reactive nitrogen oxides at two rural southeast United States sites (Great Smoky Mountains national park (GRSM) and Mammoth Cave national park (MACA)). Availability of nitrogen oxides is considered as the limiting factor to ozone production in these areas and the relative source contribution of reactive nitrogen oxides from point or mobile sources is important in understanding why these areas have high ozone. Using two independent observation-based techniques, multiple linear regression analysis and emission inventory analysis, we demonstrate that point sources contribute a minimum of 23% of total NOy at GRSM and 27% at MACA. The influence areas for these two sites, or origins of nitrogen oxides, are investigated using trajectory-cluster analysis. The result shows that air masses from the West and Southwest sweep over GRSM most frequently, while pollutants transported from the eastern half (i.e., East, Northeast, and Southeast) have limited influence (<10% out of all air masses) on air quality at GRSM. The processes responsible for formation and removal of reactive nitrogen oxides are investigated using a comprehensive 3-D air quality model (Multiscale Air Quality SImulation Platform (MAQSIP)). The NOy contribution associated with chemical transformations to NOz and O3, based on process budget analysis, is as follows: 32% and 84% for NOz, and 26% and 80% for O3 at GRSM and MACA, respectively. The similarity between NOz and O3 process budgets suggests a close association between nitrogen oxides and effective O3 production at these rural locations.

Molecular beam epitaxy growth of SrO buffer layers on graphite and graphene for the integration of complex oxides

DOE PAGES

Ahmed, Adam S.; Wen, Hua; Ohta, Taisuke; ...

2016-04-27

Here, we report the successful growth of high-quality SrO films on highly-ordered pyrolytic graphite (HOPG) and single-layer graphene by molecular beam epitaxy. The SrO layers have (001) orientation as confirmed by X-ray diffraction (XRD) while atomic force microscopy measurements show continuous pinhole-free films having rms surface roughness of <1.5 Å. Moreover, transport measurements of exfoliated graphene, after SrO deposition, show a strong dependence between the Dirac point and Sr oxidation. As a result, the SrO is leveraged as a buffer layer for more complex oxide integration via the demonstration of (001) oriented SrTiO3 grown atop a SrO/HOPG stack.

Molecular beam epitaxy growth of SrO buffer layers on graphite and graphene for the integration of complex oxides

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ahmed, Adam S.; Wen, Hua; Ohta, Taisuke

Here, we report the successful growth of high-quality SrO films on highly-ordered pyrolytic graphite (HOPG) and single-layer graphene by molecular beam epitaxy. The SrO layers have (001) orientation as confirmed by X-ray diffraction (XRD) while atomic force microscopy measurements show continuous pinhole-free films having rms surface roughness of <1.5 Å. Moreover, transport measurements of exfoliated graphene, after SrO deposition, show a strong dependence between the Dirac point and Sr oxidation. As a result, the SrO is leveraged as a buffer layer for more complex oxide integration via the demonstration of (001) oriented SrTiO3 grown atop a SrO/HOPG stack.

Process and design considerations for high-efficiency solar cells

NASA Technical Reports Server (NTRS)

Rohati, A.; Rai-Choudhury, P.

1985-01-01

This paper shows that oxide surface passivation coupled with optimum multilayer anti-reflective coating can provide approx. 3% (absolute) improvement in solar cell efficiency. Use of single-layer AR coating, without passivation, gives cell efficiencies in the range of 15 to 15.5% on high-quality, 4 ohm-cm as well as 0.1 to 0.2 ohm-cm float-zone silicon. Oxide surface passivation alone raises the cell efficiency to or = 17%. An optimum double-layer AR coating on oxide-passivated cells provides an additional approx. 5 to 10% improvement over a single-layer AR-coated cell, resulting in cell efficiencies in excess of 18%. Experimentally observed improvements are supported by model calculations and an approach to or = 20% efficient cells is discussed.

Chemical quality and oxidative stability of extra virgin olive oils from San Juan province (Argentina).

PubMed

Ceci, Liliana N; Mattar, Susana B; Carelli, Amalia A

2017-10-01

This study provides information about the chemical quality (quality indices, fatty acid profile, total polyphenols (PPs), tocopherols and pigments) and oxidative stability index (OSI) of virgin olive oils of Arbequina, Changlot Real and Coratina cultivars (San Juan province, Argentina). The influence of the cultivar and the effect of earlier harvest dates on the yields (OY), quality and OSI of the oils were also evaluated. All the oils were classified as extra virgin. The OY (L/100kg) averaged: Arbequina=13.2, Changlot Real=21.3, Coratina=18.3. The oleic acid (O) percentage, oleic to linoleic plus linolenic ratio [O/(L+Ln)], PPs and OSI were highly dependent on cultivar (Arbequina

Recent progress in oxide thermoelectric materials: p-type Ca3Co4O9 and n-type SrTiO3(-).

PubMed

Ohta, Hiromichi; Sugiura, Kenji; Koumoto, Kunihito

2008-10-06

Thermoelectric energy conversion technology to convert waste heat into electricity has received much attention. In addition, metal oxides have recently been considered as thermoelectric power generation materials that can operate at high temperatures on the basis of their potential advantages over heavy metallic alloys in chemical and thermal robustness. We have fabricated high-quality epitaxial films composed of oxide thermoelectric materials that are suitable for clarifying the intrinsic "real" properties. This review focuses on the thermoelectric properties of two representative oxide epitaxial films, p-type Ca 3Co 4O 9 and n-type SrTiO 3, which exhibit the best thermoelectric figures of merit, ZT (= S (2)sigma Tkappa (-1), S = Seebeck coefficient, sigma = electrical conductivity, kappa = thermal conductivity, and T = absolute temperature) among oxide thermoelectric materials reported to date. In addition, we introduce the recently discovered giant S of two-dimensional electrons confined within a unit cell layer thickness ( approximately 0.4 nm) of SrTiO 3.

Electron-beam-evaporated thin films of hafnium dioxide for fabricating electronic devices

DOE PAGES

Xiao, Zhigang; Kisslinger, Kim

2015-06-17

Thin films of hafnium dioxide (HfO 2) are widely used as the gate oxide in fabricating integrated circuits because of their high dielectric constants. In this paper, the authors report the growth of thin films of HfO 2 using e-beam evaporation, and the fabrication of complementary metal-oxide semiconductor (CMOS) integrated circuits using this HfO 2 thin film as the gate oxide. The authors analyzed the thin films using high-resolution transmission electron microscopy and electron diffraction, thereby demonstrating that the e-beam-evaporation-grown HfO 2 film has a polycrystalline structure and forms an excellent interface with silicon. Accordingly, we fabricated 31-stage CMOS ringmore » oscillator to test the quality of the HfO 2 thin film as the gate oxide, and obtained excellent rail-to-rail oscillation waveforms from it, denoting that the HfO 2 thin film functioned very well as the gate oxide.« less

40 CFR 50.11 - National primary and secondary ambient air quality standards for oxides of nitrogen (with...

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 2 2011-07-01 2011-07-01 false National primary and secondary ambient air quality standards for oxides of nitrogen (with nitrogen dioxide as the indicator). 50.11 Section... quality standards for oxides of nitrogen (with nitrogen dioxide as the indicator). (a) The level of the...

40 CFR 50.11 - National primary and secondary ambient air quality standards for oxides of nitrogen (with...

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 2 2010-07-01 2010-07-01 false National primary and secondary ambient air quality standards for oxides of nitrogen (with nitrogen dioxide as the indicator). 50.11 Section... quality standards for oxides of nitrogen (with nitrogen dioxide as the indicator). (a) The level of the...

Stoichiometry control of complex oxides by sequential pulsed-laser deposition from binary-oxide targets

DOE PAGES

Herklotz, A.; Dörr, Kathrin; Ward, T. Z.; ...

2015-04-03

In this paper, to have precise atomic layer control over interfaces, we examine the growth of complex oxides through the sequential deposition from binary targets by pulsed laser deposition. In situ reflection high-energy electron diffraction (RHEED) is used to control the growth and achieve films with excellent structural quality. The growth from binary oxide targets is fundamentally different from single target growth modes and shows more similarities to shuttered growth by molecular beam epitaxy. The RHEED intensity oscillations of non-stoichiometric growth are consistent with a model of island growth and accumulation of excess material on the surface that can bemore » utilized to determine the correct stoichiometry for growth. Correct monolayer doses can be determined through an envelope frequency in the RHEED intensity oscillations. In order to demonstrate the ability of this growth technique to create complex heterostructures, the artificial n = 2 and 3 Sr n +1Ti n O 3 n +1 Ruddlesden-Popper phases are grown with good long-range order. Finally, this method enables the precise unit-cell level control over the structure of perovskite-type oxides, and thus the growth of complex materials with improved structural quality and electronic functionality.« less

Stoichiometry control of complex oxides by sequential pulsed-laser deposition from binary-oxide targets

DOE PAGES

Herklotz, Andreas; Dorr, Kathrin; Ward, Thomas Zac; ...

2015-04-03

To have precise atomic layer control over interfaces, we examine the growth of complex oxides through the sequential deposition from binary targets by pulsed laser deposition. In situ reflection high-energy electron diffraction (RHEED) is used to control the growth and achieve films with excellent structural quality. The growth from binary oxide targets is fundamentally different from single target growth modes and shows more similarities to shuttered growth by molecular beam epitaxy. The RHEED intensity oscillations of non-stoichiometric growth are consistent with a model of island growth and accumulation of excess material on the surface that can be utilized to determinemore » the correct stoichiometry for growth. Correct monolayer doses can be determined through an envelope frequency in the RHEED intensity oscillations. In order to demonstrate the ability of this growth technique to create complex heterostructures, the artificial n = 2 and 3 Sr n+1Ti nO 3 n+1 Ruddlesden-Popper phases are grown with good long-range order. Furthermore, this method enables the precise unit-cell level control over the structure of perovskite-type oxides, and thus the growth of complex materials with improved structural quality and electronic functionality.« less

EXAMINATION OF THE OXIDATION PROTECTION OF ZINC COATINGS FORMED ON COPPER ALLOYS AND STEEL SUBSTRATES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Papazoglou, M.; Chaliampalias, D.; Vourlias, G.

2010-01-21

The exposure of metallic components at aggressive high temperature environments, usually limit their usage at similar application because they suffer from severe oxidation attack. Copper alloys are used in a wide range of high-quality indoor and outdoor applications, statue parts, art hardware, high strength and high thermal conductivity applications. On the other hand, steel is commonly used as mechanical part of industrial set outs or in the construction sector due to its high mechanical properties. The aim of the present work is the examination of the oxidation resistance of pack cementation zinc coatings deposited on copper, leaded brass and steelmore » substrates at elevated temperature conditions. Furthermore, an effort made to make a long-term evaluation of the coated samples durability. The oxidation results showed that bare substrates appear to have undergone severe damage comparing with the coated ones. Furthermore, the mass gain of the uncoated samples was higher than this of the zinc covered ones. Particularly zinc coated brass was found to be more resistant to oxidation conditions in which it was exposed as it has the lower mass gain as compared to the bare substrates and zinc coated copper. Zinc coated steel was also proved to be more resistive than the uncoated steel.« less

Rebonding of Se to As and Ge in Ge33As12Se55 films upon thermal annealing: Evidence from x-ray photoelectron spectra investigations

NASA Astrophysics Data System (ADS)

Wang, R. P.; Choi, D. Y.; Rode, A. V.; Madden, S. J.; Luther-Davies, B.

2007-06-01

We have measured and analyzed x-ray photoelectron spectra (XPS) of as-grown and annealed Ge33As12Se55 films compared with bulk material. We found that the as-grown film contains a large number of separated Se clusters which can coalesce with As and Ge after annealing at high temperatures. In addition, both the Ge and As 3d spectra show the presence of oxides. While the Ge oxidation increases with an increasing annealing temperature, As oxidation is almost unaffected by annealing. The difference could be due to their different electro-negativities. Our results suggest that, while thermal annealing is effective to move the film toward the bond structure of bulk glass, the simultaneous surface oxidation must be suppressed in order to achieve high quality films.

Metal Catalyst for Low-Temperature Growth of Controlled Zinc Oxide Nanowires on Arbitrary Substrates

PubMed Central

Kim, Baek Hyun; Kwon, Jae W.

2014-01-01

Zinc oxide nanowires generated by hydrothermal method present superior physical and chemical characteristics. Quality control of the growth has been very challenging and controlled growth is only achievable under very limited conditions using homogeneous seed layers with high temperature processes. Here we show the controlled ZnO nanowire growth on various organic and inorganic materials without the requirement of a homogeneous seed layer and a high temperature process. We also report the discovery of an important role of the electronegativity in the nanowire growth on arbitrary substrates. Using heterogeneous metal oxide interlayers with low-temperature hydrothermal methods, we demonstrate well-controlled ZnO nanowire arrays and single nanowires on flat or curved surfaces. A metal catalyst and heterogeneous metal oxide interlayers are found to determine lattice-match with ZnO and to largely influence the controlled alignment. These findings will contribute to the development of novel nanodevices using controlled nanowires. PMID:24625584

Mitochondrial quality control: decommissioning power plants in neurodegenerative diseases.

PubMed

Mukherjee, Rukmini; Chakrabarti, Oishee

2013-01-01

The cell has an intricate quality control system to protect its mitochondria from oxidative stress. This surveillance system is multi-tiered and comprises molecules that are present inside the mitochondria, in the cytosol, and in other organelles like the nucleus and endoplasmic reticulum. These molecules cross talk with each other and protect the mitochondria from oxidative stress. Oxidative stress is a fundamental part of early disease pathogenesis of neurodegenerative diseases. These disorders also damage the cellular quality control machinery that protects the cell against oxidative stress. This exacerbates the oxidative damage and causes extensive neuronal cell death that is characteristic of neurodegeneration.

Precursors for the polymer-assisted deposition of films

DOEpatents

McCleskey, Thomas M.; Burrell, Anthony K.; Jia, Quanxi; Lin, Yuan

2013-09-10

A polymer assisted deposition process for deposition of metal oxide films is presented. The process includes solutions of one or more metal precursor and soluble polymers having binding properties for the one or more metal precursor. After a coating operation, the resultant coating is heated at high temperatures to yield metal oxide films. Such films can be epitaxial in structure and can be of optical quality. The process can be organic solvent-free.

Air ionization as a control technology for off-gas emissions of volatile organic compounds.

PubMed

Kim, Ki-Hyun; Szulejko, Jan E; Kumar, Pawan; Kwon, Eilhann E; Adelodun, Adedeji A; Reddy, Police Anil Kumar

2017-06-01

High energy electron-impact ionizers have found applications mainly in industry to reduce off-gas emissions from waste gas streams at low cost and high efficiency because of their ability to oxidize many airborne organic pollutants (e.g., volatile organic compounds (VOCs)) to CO 2 and H 2 O. Applications of air ionizers in indoor air quality management are limited due to poor removal efficiency and production of noxious side products, e.g., ozone (O 3 ). In this paper, we provide a critical evaluation of the pollutant removal performance of air ionizing system through comprehensive review of the literature. In particular, we focus on removal of VOCs and odorants. We also discuss the generation of unwanted air ionization byproducts such as O 3 , NOx, and VOC oxidation intermediates that limit the use of air-ionizers in indoor air quality management. Copyright © 2017. Published by Elsevier Ltd.

Interface investigation of solution processed high- κ ZrO2/Si MOS structure by DLTS

NASA Astrophysics Data System (ADS)

Kumar, Arvind; Mondal, Sandip; Rao, Ksr Koteswara

The interfacial region is dominating due to the continuous downscaling and integration of high- k oxides in CMOS applications. The accurate characterization of high- k oxides/semiconductor interface has the significant importance towards its usage in memory and thin film devices. The interface traps at the high - k /semiconductor interface can be quantified by deep level transient spectroscopy (DLTS) with better accuracy in contrast to capacitance-voltage (CV) and conductance technique. We report the fabrication of high- k ZrO2 films on p-Si substrate by a simple and inexpensive sol-gel spin-coating technique. Further, the ZrO2/Si interface is characterized through DLTS. The flat-band voltage (VFB) and the density of slow interface states (oxide trapped charges) extracted from CV characteristics are 0.37 V and 2x10- 11 C/cm2, respectively. The activation energy, interface state density and capture cross-section quantified by DLTS are EV + 0.42 eV, 3.4x1011 eV- 1 cm- 2 and 5.8x10- 18 cm2, respectively. The high quality ZrO2 films own high dielectric constant 15 with low leakage current density might be an appropriate insulating layer in future electronic application. The low value of interface state density and capture cross-section are the indication of high quality interface and the defect present at the interface may not affect the device performance to a great extent. The DLTS study provides a broad understanding about the traps present at the interface of spin-coated ZrO2/Si.

Nighttime Chemistry and Morning Isoprene Can Drive Urban Ozone Downwind of a Major Deciduous Forest.

PubMed

Millet, Dylan B; Baasandorj, Munkhbayar; Hu, Lu; Mitroo, Dhruv; Turner, Jay; Williams, Brent J

2016-04-19

Isoprene is the predominant non-methane volatile organic compound emitted to the atmosphere and shapes tropospheric composition and biogeochemistry through its effects on ozone, other oxidants, aerosols, and the nitrogen cycle. Isoprene is emitted naturally by vegetation during daytime, when its photo-oxidation is rapid, and in the presence of nitrogen oxides (NOx) produces ozone and degrades air quality in polluted regions. Here, we show for a city downwind of an isoprene-emitting forest (St. Louis, MO) that isoprene actually peaks at night; ambient levels then endure, owing to low nighttime OH radical concentrations. Nocturnal chemistry controls the fate of that isoprene and the likelihood of a high-ozone episode the following day. When nitrate (NO3) radicals are suppressed, high isoprene persists through the night, providing photochemical fuel upon daybreak and leading to a dramatic late-morning ozone peak. On nights with significant NO3, isoprene is removed before dawn; days with low morning isoprene then have lower ozone with a more typical afternoon peak. This biogenic-anthropogenic coupling expands the daily high-ozone window and likely has an opposite O3-NOx response to what would otherwise be expected, with implications for exposure and air-quality management in cities that, like St. Louis, are downwind of major isoprene-emitting forests.

76 FR 53853 - Approval and Promulgation of Implementation Plans and Designation of Areas for Air Quality...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-30

... nitrogen oxides (NO X ) and VOCs in the presence of sunlight and high ambient temperatures. NO X and VOCs... Quality, the City of Baton Rouge, and the Chamber of Greater Baton Rouge all formally requested a waiver... area. EPA denied these requests. The City and the Chamber filed a Petition for Review in the U.S. Court...

Recovery of iron oxide from coal fly ash

DOEpatents

Dobbins, Michael S.; Murtha, Marlyn J.

1983-05-31

A high quality iron oxide concentrate, suitable as a feed for blast and electric reduction furnaces is recovered from pulverized coal fly ash. The magnetic portion of the fly ash is separated and treated with a hot strong alkali solution which dissolves most of the silica and alumina in the fly ash, leaving a solid residue and forming a precipitate which is an acid soluble salt of aluminosilicate hydrate. The residue and precipitate are then treated with a strong mineral acid to dissolve the precipitate leaving a solid residue containing at least 90 weight percent iron oxide.

40 CFR 50.4 - National primary ambient air quality standards for sulfur oxides (sulfur dioxide).

Code of Federal Regulations, 2011 CFR

2011-07-01

... standards for sulfur oxides (sulfur dioxide). 50.4 Section 50.4 Protection of Environment ENVIRONMENTAL....4 National primary ambient air quality standards for sulfur oxides (sulfur dioxide). (a) The level...). (c) Sulfur oxides shall be measured in the ambient air as sulfur dioxide by the reference method...

40 CFR 50.4 - National primary ambient air quality standards for sulfur oxides (sulfur dioxide).

Code of Federal Regulations, 2012 CFR

2012-07-01

... standards for sulfur oxides (sulfur dioxide). 50.4 Section 50.4 Protection of Environment ENVIRONMENTAL....4 National primary ambient air quality standards for sulfur oxides (sulfur dioxide). (a) The level...). (c) Sulfur oxides shall be measured in the ambient air as sulfur dioxide by the reference method...

40 CFR 50.4 - National primary ambient air quality standards for sulfur oxides (sulfur dioxide).

Code of Federal Regulations, 2013 CFR

2013-07-01

... standards for sulfur oxides (sulfur dioxide). 50.4 Section 50.4 Protection of Environment ENVIRONMENTAL....4 National primary ambient air quality standards for sulfur oxides (sulfur dioxide). (a) The level...). (c) Sulfur oxides shall be measured in the ambient air as sulfur dioxide by the reference method...

40 CFR 50.4 - National primary ambient air quality standards for sulfur oxides (sulfur dioxide).

Code of Federal Regulations, 2014 CFR

2014-07-01

... standards for sulfur oxides (sulfur dioxide). 50.4 Section 50.4 Protection of Environment ENVIRONMENTAL....4 National primary ambient air quality standards for sulfur oxides (sulfur dioxide). (a) The level...). (c) Sulfur oxides shall be measured in the ambient air as sulfur dioxide by the reference method...

Effect of dietary restriction on sperm characteristic and oxidative status on testicular tissue in young rats exposed to long-term heat stress.

PubMed

Aydilek, N; Varisli, O; Kocyigit, A; Taskin, A; Kaya, M S

2015-11-01

This study was conducted to evaluate the effects of dietary restriction on oxidative status and sperm parameters in rats exposed to long-term heat stress. Forty healthy Sprague-Dawley rats, aged 2.5 month, were divided into four groups of 10 with respect to feeding and temperature regimen (room temperature (22 °C)-ad libitum, room temperature-dietary restriction (40%), high temperature (38 °C)-ad libitum, high temperature-dietary restriction). At the end of the 9th week, some oxidants (lipid hydroperoxide, total oxidant status, oxidative stress index) and antioxidants (total antioxidant status, sulfhydryl groups, ceruloplasmin, paraoxonase and arylesterase activities) were measured in the testis tissue. The concentration, motility, volume, abnormal sperm count, acrosome and membrane integrity of epididymal spermatozoon and intratesticular testosterone levels were evaluated. High temperature did not change oxidative and antioxidative parameters except for sulfhydryl groups and ceruloplasmin, yet it impaired all sperm values. Neither sperm values nor oxidative status apart from sulfhydryl groups, ceruloplasmin and arylesterase was affected by dietary restriction in the testis tissue. These results suggest that long-term heat stress does not have a significant effect on testicular oxidative status, while the spermatozoa are sensitive to heat stress in young rats. Dietary restriction failed to improve the sperm quality and oxidative status except some individual antioxidant parameters; conversely, it decreased intratesticular testosterone level in the young rats exposed to long-term heat stress. © 2014 Blackwell Verlag GmbH.

Burning Graphene Layer-by-Layer

PubMed Central

Ermakov, Victor A.; Alaferdov, Andrei V.; Vaz, Alfredo R.; Perim, Eric; Autreto, Pedro A. S.; Paupitz, Ricardo; Galvao, Douglas S.; Moshkalev, Stanislav A.

2015-01-01

Graphene, in single layer or multi-layer forms, holds great promise for future electronics and high-temperature applications. Resistance to oxidation, an important property for high-temperature applications, has not yet been extensively investigated. Controlled thinning of multi-layer graphene (MLG), e.g., by plasma or laser processing is another challenge, since the existing methods produce non-uniform thinning or introduce undesirable defects in the basal plane. We report here that heating to extremely high temperatures (exceeding 2000 K) and controllable layer-by-layer burning (thinning) can be achieved by low-power laser processing of suspended high-quality MLG in air in “cold-wall” reactor configuration. In contrast, localized laser heating of supported samples results in non-uniform graphene burning at much higher rates. Fully atomistic molecular dynamics simulations were also performed to reveal details of oxidation mechanisms leading to uniform layer-by-layer graphene gasification. The extraordinary resistance of MLG to oxidation paves the way to novel high-temperature applications as continuum light source or scaffolding material. PMID:26100466

Method of fabricating optical waveguides by ion implantation doping

DOEpatents

Appleton, B.R.; Ashley, P.R.; Buchal, C.J.

1987-03-24

A method for fabricating high-quality optical waveguides in optical quality oxide crystals by ion implantation doping and controlled epitaxial recrystallization is provided. Masked LiNbO/sub 3/ crystals are implanted with high concentrations of Ti dopant at ion energies of about 360 keV while maintaining the crystal near liquid nitrogen temperature. Ion implantation doping produces an amorphous, Ti-rich nonequilibrium phase in the implanted region. Subsequent thermal annealing in a water-saturated oxygen atmosphere at up to 1000/degree/C produces solid-phase epitaxial regrowth onto the crystalline substrate. A high-quality crystalline layer results which incorporates the Ti into the crystal structure at much higher concentrations than is possible by standard diffusion techniques, and this implanted region has excellent optical waveguiding properties.

Re-evaluation of peroxide value as an indicator of the quality of edible oils.

PubMed

Shiozawa, Satoshi; Tanaka, Masaharu; Ohno, Katsutoshi; Nagao, Yasuhiro; Yamada, Toshihiro

2007-06-01

The oxidation of oils has important effects on the quality of oily foods, such as instant noodles. In particular, the generation of aldehydes, which accompanies the oxidation of oils, is one of the first factors to reduce food quality. We examined various indicators of oil quality during temperature-accelerated storage and found that peroxide value (POV) was highly correlated with the total concentration of major odorants. Moreover, the correlation of POV with the total concentration of five unsaturated aldehydes (t-2-heptenal, t-2-octenal, t-2-decenal, t-2-undecenal and t,t-2,4-decadienal) that show strong cytotoxicity was greater than the correlation of POV with the total concentration of major odorants. The maximum allowable concentration of the five aldehydes was calculated based on the 'no observed adverse-effect level' of the aldehyde that showed the highest cytotoxicity, t,t-2,4-decadienal, along with the human daily oil intake. We showed that it is useful to utilize POV as an indicator to control food quality and safety.

Storing red blood cells with vitamin C and N-acetylcysteine prevents oxidative stress-related lesions: a metabolomics overview

PubMed Central

Pallotta, Valeria; Gevi, Federica; D’Alessandro, Angelo; Zolla, Lello

2014-01-01

Background Recent advances in red blood cell metabolomics have paved the way for further improvements of storage solutions. Materials and methods In the present study, we exploited a validated high performance liquid chromatography-mass spectrometry analytical workflow to determine the effects of vitamin C and N-acetylcysteine supplementation (anti-oxidants) on the metabolome of erythrocytes stored in citrate-phosphate-dextrose saline-adenine-glucose-mannitol medium under blood bank conditions. Results We observed decreased energy metabolism fluxes (glycolysis and pentose phosphate pathway). A tentative explanation of this phenomenon could be related to the observed depression of the uptake of glucose, since glucose and ascorbate are known to compete for the same transporter. Anti-oxidant supplementation was effective in modulating the redox poise, through the promotion of glutathione homeostasis, which resulted in decreased haemolysis and less accumulation of malondialdehyde and oxidation by-products (including oxidized glutathione and prostaglandins). Discussion Anti-oxidants improved storage quality by coping with oxidative stress at the expense of glycolytic metabolism, although reservoirs of high energy phosphate compounds were preserved by reduced cyclic AMP-mediated release of ATP. PMID:25074788

Low-quality birds do not display high-quality signals: The cysteine-pheomelanin mechanism of honesty

PubMed Central

Galván, Ismael; Wakamatsu, Kazumasa; Camarero, Pablo R; Mateo, Rafael; Alonso-Alvarez, Carlos

2015-01-01

The mechanisms that make that the costs of producing high-quality signals are unaffordable to low-quality signalers are a current issue in animal communication. The size of the melanin-based bib of male house sparrows Passer domesticus honestly signals quality. We induced the development of new bibs while treating males with buthionine-sulfoximine (BSO), a substance that depletes the levels of the antioxidant glutathione (GSH) and the amino acid cysteine, two elements that switch melanogenesis from eumelanin to pheomelanin. Final bib size is negatively related to pheomelanin levels in the bib feathers. BSO reduced cysteine and GSH levels in all birds, but improved phenotypes (bibs larger than controls) were only expressed by high-quality birds (BSO birds with largest bibs initially). Negative associations between final bib size and cysteine levels in erythrocytes, and between pheomelanin and cysteine levels, were observed in high-quality birds only. These findings suggest that a mechanism uncoupling pheomelanin and cysteine levels may have evolved in low-quality birds to avoid producing bibs of size not corresponding to their quality and greater relative costs. Indeed, greater oxidative stress in cells was not observed in low-quality birds. This may represent the first mechanism maintaining signal honesty without producing greater relative costs on low-quality signalers. PMID:25330349

Binary Oxide p-n Heterojunction Piezoelectric Nanogenerators with an Electrochemically Deposited High p-Type Cu2O Layer.

PubMed

Baek, Seung Ki; Kwak, Sung Soo; Kim, Joo Sung; Kim, Sang Woo; Cho, Hyung Koun

2016-08-31

The high performance of ZnO-based piezoelectric nanogenerators (NGs) has been limited due to the potential screening from intrinsic electron carriers in ZnO. We have demonstrated a novel approach to greatly improve piezoelectric power generation by electrodepositing a high-quality p-type Cu2O layer between the piezoelectric semiconducting film and the metal electrode. The p-n heterojunction using only oxides suppresses the screening effect by forming an intrinsic depletion region, and thus sufficiently enhances the piezoelectric potential, compared to the pristine ZnO piezoelectric NG. Interestingly, a Sb-doped Cu2O layer has high mobility and low surface trap states. Thus, this doped layer is an attractive p-type material to significantly improve piezoelectric performance. Our results revealed that p-n junction NGs consisting of Au/ZnO/Cu2O/indium tin oxide with a Cu2O:Sb (cuprous oxide with a small amount of antimony) layer of sufficient thickness (3 μm) exhibit an extraordinarily high piezoelectric potential of 0.9 V and a maximum output current density of 3.1 μA/cm(2).

Synthesis of nanostructured iron oxides and new magnetic ceramics using sol-gel and SPS techniques

NASA Astrophysics Data System (ADS)

Papynov, E. K.; Shichalin, O. O.; Belov, A. A.; Portnyagin, A. S.; Mayorov, V. Yu.; Gridasova, E. A.; Golub, A. V.; Nepomnyashii, A. S.; Tananaev, I. G.; Avramenko, V. A.

2017-02-01

The original way of synthesis of nanostructured iron oxides and based on them magnetic ceramics via sequential combination of sol-gel and SPS technologies has been suggested. High quality of nanostructured iron oxides is defined by porous structure (Sspec up to 47,3 n2/g) and by phase composition of mixed and individual crystal phases (γ-Fe2O3/Fe3O4 i α-Fe2O3), depending on synthesis conditions. High-temperature SPS consolidation of nanostructured hematite powder, resulting in magnetic ceramics of high mechanical strength (fracture strength 249 MPa) has been investigated. Peculiarities of change of phase composition and composite's microstructure in the range of SPS temperatures from 700 to 900 °C have been revealed. Magnetic properties have been studied and regularities of change of magnetization (Ms) and coercive force (Hc) values of the ceramics with respect to SPS sintering temperature have been described.

Effect of Thermal Processing towards Lipid Oxidation and Non-enzymatic Browning Reactions of Antartic Krill (Euphausia superba) Meal.

PubMed

Liu, Yanzi; Cong, Peixu; Li, Beijia; Song, Yu; Liu, Yanjun; Xu, Jie; Xue, Changhu

2018-04-13

Antarctic krill is a huge source of biomass and prospective high-quality lipid source. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), nutritionally important lipid components with poor oxidative stability, were used as markers of oxidation during thermal processing of Antarctic krill (Euphausia superba) meal by evaluating the lipolysis, lipid oxidation, and non-enzymatic browning reactions. Liquid chromatography-mass spectrometry of the phospholipids (PLs) and the main oxidation products of free fatty acids (FFAs) and phosphatidylcholine (PC) was effective for evaluating the oxidation of EPA and DHA. During boiling, oxidation of EPA and DHA in the FFA and PC fractions and hydrolysis of the fatty acids at the sn-2 position of the PLs were predominant. The changes in PC during drying were mainly attributed to the oxidation of EPA and DHA. Heat treatment increased the oxidation products and concentration of hydrophobic pyrrole owing to pyrrolization between phosphatidylethanolamine (PE) and the lipid oxidation products. The lipid oxidation level of Antarctic krill increased after drying, owing to prolonged heating under the severe conditions. This article is protected by copyright. All rights reserved.

40 CFR 50.5 - National secondary ambient air quality standard for sulfur oxides (sulfur dioxide).

Code of Federal Regulations, 2014 CFR

2014-07-01

... standard for sulfur oxides (sulfur dioxide). 50.5 Section 50.5 Protection of Environment ENVIRONMENTAL....5 National secondary ambient air quality standard for sulfur oxides (sulfur dioxide). (a) The level... than 0.05 ppm shall be rounded up). (b) Sulfur oxides shall be measured in the ambient air as sulfur...

40 CFR 50.5 - National secondary ambient air quality standard for sulfur oxides (sulfur dioxide).

Code of Federal Regulations, 2013 CFR

2013-07-01

... standard for sulfur oxides (sulfur dioxide). 50.5 Section 50.5 Protection of Environment ENVIRONMENTAL....5 National secondary ambient air quality standard for sulfur oxides (sulfur dioxide). (a) The level... than 0.05 ppm shall be rounded up). (b) Sulfur oxides shall be measured in the ambient air as sulfur...

40 CFR 50.4 - National primary ambient air quality standards for sulfur oxides (sulfur dioxide).

Code of Federal Regulations, 2010 CFR

2010-07-01

... standards for sulfur oxides (sulfur dioxide). 50.4 Section 50.4 Protection of Environment ENVIRONMENTAL....4 National primary ambient air quality standards for sulfur oxides (sulfur dioxide). Link to an... to or greater than 0.005 ppm shall be rounded up). (c) Sulfur oxides shall be measured in the ambient...

40 CFR 50.5 - National secondary ambient air quality standard for sulfur oxides (sulfur dioxide).

Code of Federal Regulations, 2012 CFR

2012-07-01

... standard for sulfur oxides (sulfur dioxide). 50.5 Section 50.5 Protection of Environment ENVIRONMENTAL....5 National secondary ambient air quality standard for sulfur oxides (sulfur dioxide). (a) The level... than 0.05 ppm shall be rounded up). (b) Sulfur oxides shall be measured in the ambient air as sulfur...

High-Quality Draft Genome Sequence of Desulfovibrio carbinoliphilus FW-101-2B, an Organic Acid-Oxidizing Sulfate-Reducing Bacterium Isolated from Uranium(VI)-Contaminated Groundwater

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ramsay, Bradley D.; Hwang, Chiachi; Woo, Hannah L.

2015-03-12

Desulfovibrio carbinoliphilus subsp. oakridgensis FW-101-2B is an anaerobic, organic acid/alcohol-oxidizing, sulfate-reducing δ-proteobacterium. FW-101-2B was isolated from contaminated groundwater at The Field Research Center at Oak Ridge National Lab after in situ stimulation for heavy metal-reducing conditions. The genome will help elucidate the metabolic potential of sulfate-reducing bacteria during uranium reduction.

Proximate composition and lipid stability of dourado (Salminus brasilensis, Cuvier, 1817) fillets exposed to different levels of ammonia and oxygen in vivo.

PubMed

Veeck, Ana Paula L; Garcia, Luciano O; Baldisserotto, Bernardo; Zaniboni Filho, Evoy; Emanuelli, Tatiana

2013-08-15

The ammonia and oxygen levels of water are physicochemical parameters that affect fish physiology. Thus, we hypothesized that in vivo exposure to stressful ammonia and oxygen levels will affect the post-mortem quality of the fish. Therefore, in this study, the effects of in vivo exposure to stressful ammonia and oxygen levels on the composition and content of thiobarbituric acid reactive substances in fillets from dourado (Salminus brasiliensis) and on the lipid oxidation of these fillets during frozen storage were evaluated. Short-term exposure (12 h) to stressful environmental conditions (low oxygen and high ammonia levels) did not change the composition of the flesh. However, longer exposure (15 days) to these stressful conditions caused significant changes in the composition of the flesh. Exposure to a stressful ammonia level before slaughtering increased the susceptibility of the fish fillets to lipid oxidation during frozen storage. In contrast, exposure to low oxygen levels did not increase the lipid oxidation rate of the fillets. These results indicate that the in vivo exposure to high ammonia levels may reduce the quality and stability of dourado fillets. © 2013 Society of Chemical Industry.

Nanomagnetism study of highly-ordered iron oxide nanocrystal assemblies fabricated by the Langmuir-Blodgett technique.

PubMed

Zhang, HaiTao; Bao, NiNa; Yuan, Du; Ding, Jun

2013-09-21

Iron oxide nanocrystals are ideal building blocks for the construction of flexible nanodevices whose performance can be modulated by controlling the morphology of isolated particles and their organizational form. This work demonstrates the fabrication of high quality Langmuir-Blodgett (LB) nanocrystal assemblies with limited overlapping and higher coverage by systemically and combinatorially optimizing the parameters of compression pressure and quantity of spread nanocrystals. Monodispersed iron oxide nanocrystals with a diameter of 11.8 nm were synthesized by thermal decomposition of Fe(CO)5 in trioctylamine with the presence of oleic acid. Multilayer nanocrystal assemblies were obtained through a layer-by-layer (LBL) process by repeating the transfer procedure after their hydrophilicity had been improved via treatment in a UV-ozone oven. The quality of nanocrystal assemblies was investigated by UV-vis spectrometry and scanning electron microscopy. The nanomagnetism for the nanostructures of different combination manners was studied systemically by a superconducting quantum interference device (SQUID). A lower superparamagnetic blocking temperature was found in the monolayer Fe3O4 nanocrystal assembly. The superparamagnetic blocking temperature in magnetic nanocrystal assemblies could be tuned through modifying the interparticle interactions among the interlayer and intralayers by controlling the layer number of the assemblies.

Modelling and analysis of ozone concentration by artificial intelligent techniques for estimating air quality

NASA Astrophysics Data System (ADS)

Taylan, Osman

2017-02-01

High ozone concentration is an important cause of air pollution mainly due to its role in the greenhouse gas emission. Ozone is produced by photochemical processes which contain nitrogen oxides and volatile organic compounds in the lower atmospheric level. Therefore, monitoring and controlling the quality of air in the urban environment is very important due to the public health care. However, air quality prediction is a highly complex and non-linear process; usually several attributes have to be considered. Artificial intelligent (AI) techniques can be employed to monitor and evaluate the ozone concentration level. The aim of this study is to develop an Adaptive Neuro-Fuzzy inference approach (ANFIS) to determine the influence of peripheral factors on air quality and pollution which is an arising problem due to ozone level in Jeddah city. The concentration of ozone level was considered as a factor to predict the Air Quality (AQ) under the atmospheric conditions. Using Air Quality Standards of Saudi Arabia, ozone concentration level was modelled by employing certain factors such as; nitrogen oxide (NOx), atmospheric pressure, temperature, and relative humidity. Hence, an ANFIS model was developed to observe the ozone concentration level and the model performance was assessed by testing data obtained from the monitoring stations established by the General Authority of Meteorology and Environment Protection of Kingdom of Saudi Arabia. The outcomes of ANFIS model were re-assessed by fuzzy quality charts using quality specification and control limits based on US-EPA air quality standards. The results of present study show that the ANFIS model is a comprehensive approach for the estimation and assessment of ozone level and is a reliable approach to produce more genuine outcomes.

Highly reflective Ag-Cu alloy-based ohmic contact on p-type GaN using Ru overlayer.

PubMed

Son, Jun Ho; Jung, Gwan Ho; Lee, Jong-Lam

2008-12-15

We report on a metallization scheme of high reflectance, low resistance, and smooth surface morphology ohmic contact on p-type GaN. Ag-Cu alloy/Ru contact showed low contact resistivity as low as 6.2 x 10(-6) Ohms cm(2) and high reflectance of 91% at 460 nm after annealing at 400 degrees C in air ambient. The oxidation annealing promoted the out-diffusion of Ga atoms to dissolve in an Ag-Cu layer with the formation of an Ag-Ga solid solution, lowering the contact resistivity. The Ru overlayer acts as a diffusion barrier for excessive oxygen incorporation during oxidation annealing, resulting in high reflectance, good thermal stability, and smooth surface quality of the contact.

High Stability Performance of Quinary Indium Gallium Zinc Aluminum Oxide Films and Thin-Film Transistors Deposited Using Vapor Cooling Condensation Method

NASA Astrophysics Data System (ADS)

Lin, Yung-Hao; Lee, Ching-Ting

2017-08-01

High-quality indium gallium zinc aluminum oxide (IGZAO) thin films with various Al contents have been deposited using the vapor cooling condensation method. The electron mobility of the IGZAO films was improved by 89.4% on adding Al cation to IGZO film. The change in the electron concentration and mobility of the IGZAO films was 7.3% and 7.0%, respectively, when the temperature was changed from 300 K to 225 K. These experimental results confirm the high performance and stability of the IGZAO films. The performance stability mechanisms of IGZAO thin-film transistors (TFTs) were investigated in comparison with IGZO TFTs.

Discovery of Fe–Ce Oxide/BiVO 4 Photoanodes through Combinatorial Exploration of Ni–Fe–Co–Ce Oxide Coatings

DOE PAGES

Shinde, Aniketa; Guevarra, Dan; Liu, Guiji; ...

2016-08-23

An efficient photoanode is a prerequisite for a viable solar fuels technology. The challenges to realizing an efficient photoanode include the integration of a semiconductor light absorber and a metal oxide electrocatalyst to optimize corrosion protection, light trapping, hole transport, and photocarrier recombination sites. In order to efficiently explore metal oxide coatings, we employ a high throughput methodology wherein a uniform BiVO 4 film is coated with 858 unique metal oxide coatings covering a range of metal oxide loadings and the full (Ni-Fe-Co-Ce)Ox pseudo-quaternary composition space. Photoelectrochemical characterization of the photoanodes reveals that specific combinations of metal oxide composition andmore » loading provide up to a 13-fold increase in the maximum photoelectrochemical power generation for oxygen evolution in pH 13 electrolyte. Through mining of the high throughput data we identify composition regions that form improved interfaces with BiVO 4. Of particular note, integrated photoanodes with catalyst compositions in the range Fe (0.4-0.6)Ce (0.6-0.4)O x exhibit high interface quality and excellent photoelectrochemical power conversion. Furthermore, for scaled-up inkjet-printed electrodes and photoanodic electrodeposition of this composition on BiVO 4 we can confirm the discovery and the synthesis-independent interface improvement of (Fe-Ce)O x coatings on BiVO 4.« less

Discovery of Fe–Ce Oxide/BiVO 4 Photoanodes through Combinatorial Exploration of Ni–Fe–Co–Ce Oxide Coatings

DOE PAGES

Shinde, Aniketa; Guevarra, Dan; Liu, Guiji; ...

2016-08-23

An efficient photoanode is a prerequisite for a viable solar fuels technology. The challenges to realizing an efficient photoanode include the integration of a semiconductor light absorber and a metal oxide electrocatalyst to optimize corrosion protection, light trapping, hole transport, and photocarrier recombination sites. In order to efficiently explore metal oxide coatings, we employ a high throughput methodology wherein a uniform BiVO 4 film is coated with 858 unique metal oxide coatings covering a range of metal oxide loadings and the full (Ni-Fe-Co-Ce)O x pseudo-quaternary composition space. Photoelectrochemical characterization of the photoanodes reveals that specific combinations of metal oxide compositionmore » and loading provide up to a 13-fold increase in the maximum photoelectrochemical power generation for oxygen evolution in pH 13 electrolyte. Through mining of the high throughput data we identify composition regions that form improved interfaces with BiVO 4. Of particular note, integrated photoanodes with catalyst compositions in the range Fe (0.4-0.6)Ce (0.6-0.4)O x exhibit high interface quality and excellent photoelectrochemical power conversion. Furthermore, for scaled-up inkjet-printed electrodes and photoanodic electrodeposition of this composition on BiVO 4 we can confirm the discovery and the synthesis-independent interface improvement of (Fe-Ce)O x coatings on BiVO 4.« less

Process for growing a film epitaxially upon a MgO surface

DOEpatents

McKee, Rodney Allen; Walker, Frederick Joseph

1997-01-01

A process and structure wherein optical quality perovskites, such as BaTiO.sub.3 or SrTiO.sub.3, are grown upon a single crystal MgO substrate involves the epitaxial build up of alternating planes of TiO.sub.2 and metal oxide wherein the first plane grown upon the MgO substrate is a plane of TiO.sub.2. The layering sequence involved in the film build up reduces problems which would otherwise result from the interfacial electrostatics at the first atomic layers, and these oxides can be stabilized as commensurate thin films at a unit cell thickness or grown with high crystal quality to thicknesses of 0.5-0.7 .mu.m for optical device applications.

Development of EPA aircraft piston engine emission standards. [for air quality

NASA Technical Reports Server (NTRS)

Houtman, W.

1976-01-01

Piston engine light aircraft are significant sources of carbon monoxide in the vicinity of high activity general aviation airports. Substantial reductions in carbon monoxide were achieved by fuel mixture leaning using improved fuel management systems. The air quality impact of the hydrocarbon and oxides of nitrogen emissions from piston engine light aircraft were insufficient to justify the design constraints being confronted in present control system developments.

Atmospheric Photooxidation Products and Chemistry of Current-use Pesticides

NASA Astrophysics Data System (ADS)

Murschell, T.; Farmer, D.

2017-12-01

Pesticides are widely used in agricultural, commercial, and residential applications across the United States. Pesticides can volatilize off targets and travel long distances, with atmospheric lifetimes determined by both physical and chemical loss processes. In particular, oxidation by the hydroxyl radical (OH) can reduce the lifetime and thus atmospheric transport of pesticides, though the rates and oxidation products of atmospheric pesticide oxidation are poorly understood. Here, we investigate reactions of current-use pesticides with OH. MCPA, triclopyr, and fluroxypyr are herbicides that are often formulated together to target broadleaf weeds. We detect these species in the gas-phase using real-time high resolution chemical ionization mass spectrometry (CIMS) with both acetate and iodide reagent ions. We used an Oxidative Flow Reactor to explore OH radical oxidation and photolysis of these compounds, simulating up to 5 equivalent days of atmospheric aging by OH. Use of two ionization schemes allowed for the more complete representation of the OH radical oxidation of the three pesticides. The high resolution mass spectra allows us to deduce structures of the oxidation products and identify multi-generational chemistry. In addition, we observe nitrogen oxides, as well as isocyanic acid (HNCO), from some nitrogen-containing pesticides. We present yields of species of atmospheric importance, including NOx and halogen species and consider their impact on air quality following pesticide application.

Improving the optoelectronic properties of titanium-doped indium tin oxide thin films

NASA Astrophysics Data System (ADS)

Taha, Hatem; Jiang, Zhong-Tao; Henry, David J.; Amri, Amun; Yin, Chun-Yang; Mahbubur Rahman, M.

2017-06-01

The focus of this study is on a sol-gel method combined with spin-coating to prepare high-quality transparent conducting oxide (TCO) films. The structural, morphological, optical and electrical properties of sol-gel-derived pure and Ti-doped indium tin oxide (ITO) thin films were studied as a function of the concentration of the Ti (i.e. 0 at%, 2 at% and 4 at%) and annealing temperatures (150 °C-600 °C). FESEM measurements indicate that all the films are ˜350 nm thick. XRD analysis confirmed the cubic bixbyite structure of the polycrystalline indium oxide phase for all of the thin films. Increasing the Ti ratio, as well as the annealing temperature, improved the crystallinity of the films. Highly crystalline structures were obtained at 500 °C, with average grain sizes of about 50, 65 and 80 nm for Ti doping of 0 at%, 2 at% and 4 at%, respectively. The electrical and optical properties improved as the annealing temperature increased, with an enlarged electronic energy band gap and an optical absorption edge below 280 nm. In particular, the optical transmittance and electrical resistivity of the samples with a 4 at% Ti content improved from 87% and 7.10 × 10-4 Ω.cm to 92% and 1.6 × 10-4 Ω.cm, respectively. The conductivity, especially for the annealing temperature at 150 °C, is acceptable for many applications such as flexible electronics. These results demonstrate that unlike the more expensive and complex vacuum sputtering process, high-quality Ti-doped ITO films can be achieved by fast processing, simple wet-chemistry, and easy doping level control with the possibility of producing films with high scalability.

Molecular beam epitaxy growth of niobium oxides by solid/liquid state oxygen source and lithium assisted metal-halide chemistry

NASA Astrophysics Data System (ADS)

Tellekamp, M. Brooks; Greenlee, Jordan D.; Shank, Joshua C.; Doolittle, W. Alan

2015-09-01

In order to consistently grow high quality niobium oxides and lithium niobium oxides, a novel solid/liquid state oxygen source, LiClO4, has been implemented in a molecular beam epitaxy (MBE) system. LiClO4 is shown to decompose into both molecular and atomic oxygen upon heating. This allows oxidation rates similar to that of molecular oxygen but at a reduced overall beam flux, quantified by in situ Auger analysis. LiClO4 operation is decomposition limited to less than 400 °C, and other material limitations are identified. The design of a custom near-ambient NbCl5 effusion cell is presented, which improves both short and long term stability. Films of Nb oxidation state +2, +3, and +5 are grown using these new tools, including the multi-functional sub-oxide LiNbO2.

Ultra-thin silicon oxide layers on crystalline silicon wafers: Comparison of advanced oxidation techniques with respect to chemically abrupt SiO2/Si interfaces with low defect densities

NASA Astrophysics Data System (ADS)

Stegemann, Bert; Gad, Karim M.; Balamou, Patrice; Sixtensson, Daniel; Vössing, Daniel; Kasemann, Martin; Angermann, Heike

2017-02-01

Six advanced oxidation techniques were analyzed, evaluated and compared with respect to the preparation of high-quality ultra-thin oxide layers on crystalline silicon. The resulting electronic and chemical SiO2/Si interface properties were determined by a combined x-ray photoemission (XPS) and surface photovoltage (SPV) investigation. Depending on the oxidation technique, chemically abrupt SiO2/Si interfaces with low densities of interface states were fabricated on c-Si either at low temperatures, at short times, or in wet-chemical environment, resulting in each case in excellent interface passivation. Moreover, the beneficial effect of a subsequent forming gas annealing (FGA) step for the passivation of the SiO2/Si interface of ultra-thin oxide layers has been proven. Chemically abrupt SiO2/Si interfaces have been shown to generate less interface defect states.

Hall effect measurements of high-quality M n3CuN thin films and the electronic structure

NASA Astrophysics Data System (ADS)

Matsumoto, Toshiki; Hatano, Takafumi; Urata, Takahiro; Iida, Kazumasa; Takenaka, Koshi; Ikuta, Hiroshi

2017-11-01

The physical properties of M n3CuN were studied using thin films. We found that an annealing process was very effective to improve the film quality, the key of which was the use of Ti that prevented the formation of oxide impurities. Using these high-quality thin films, we found strong strain dependence for the ferromagnetic transition temperature (TC) and a sign change of the Hall coefficient at TC. The analysis of Hall coefficient data revealed a sizable decrease of hole concentration and a large increase of electron mobility below TC, which is discussed in relation to the electronic structure of this material.

76 FR 11082 - Approval and Promulgation of Air Quality Implementation Plans; Ohio; Oxides of Nitrogen Budget...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-01

... Promulgation of Air Quality Implementation Plans; Ohio; Oxides of Nitrogen Budget Trading Program; Technical... concerning 240 allowances under the Nitrogen Oxides Budget Trading Program added to the SIP by EPA rulemaking... EPA approve rule revisions [[Page 11083

Spray-combustion synthesis: Efficient solution route to high-performance oxide transistors

PubMed Central

Yu, Xinge; Smith, Jeremy; Zhou, Nanjia; Zeng, Li; Guo, Peijun; Xia, Yu; Alvarez, Ana; Aghion, Stefano; Lin, Hui; Yu, Junsheng; Chang, Robert P. H.; Bedzyk, Michael J.; Ferragut, Rafael; Marks, Tobin J.; Facchetti, Antonio

2015-01-01

Metal-oxide (MO) semiconductors have emerged as enabling materials for next generation thin-film electronics owing to their high carrier mobilities, even in the amorphous state, large-area uniformity, low cost, and optical transparency, which are applicable to flat-panel displays, flexible circuitry, and photovoltaic cells. Impressive progress in solution-processed MO electronics has been achieved using methodologies such as sol gel, deep-UV irradiation, preformed nanostructures, and combustion synthesis. Nevertheless, because of incomplete lattice condensation and film densification, high-quality solution-processed MO films having technologically relevant thicknesses achievable in a single step have yet to be shown. Here, we report a low-temperature, thickness-controlled coating process to create high-performance, solution-processed MO electronics: spray-combustion synthesis (SCS). We also report for the first time, to our knowledge, indium-gallium-zinc-oxide (IGZO) transistors having densification, nanoporosity, electron mobility, trap densities, bias stability, and film transport approaching those of sputtered films and compatible with conventional fabrication (FAB) operations. PMID:25733848

Spray-combustion synthesis: efficient solution route to high-performance oxide transistors.

PubMed

Yu, Xinge; Smith, Jeremy; Zhou, Nanjia; Zeng, Li; Guo, Peijun; Xia, Yu; Alvarez, Ana; Aghion, Stefano; Lin, Hui; Yu, Junsheng; Chang, Robert P H; Bedzyk, Michael J; Ferragut, Rafael; Marks, Tobin J; Facchetti, Antonio

2015-03-17

Metal-oxide (MO) semiconductors have emerged as enabling materials for next generation thin-film electronics owing to their high carrier mobilities, even in the amorphous state, large-area uniformity, low cost, and optical transparency, which are applicable to flat-panel displays, flexible circuitry, and photovoltaic cells. Impressive progress in solution-processed MO electronics has been achieved using methodologies such as sol gel, deep-UV irradiation, preformed nanostructures, and combustion synthesis. Nevertheless, because of incomplete lattice condensation and film densification, high-quality solution-processed MO films having technologically relevant thicknesses achievable in a single step have yet to be shown. Here, we report a low-temperature, thickness-controlled coating process to create high-performance, solution-processed MO electronics: spray-combustion synthesis (SCS). We also report for the first time, to our knowledge, indium-gallium-zinc-oxide (IGZO) transistors having densification, nanoporosity, electron mobility, trap densities, bias stability, and film transport approaching those of sputtered films and compatible with conventional fabrication (FAB) operations.

Comparative Study of HfTa-based gate-dielectric Ge metal-oxide-semiconductor capacitors with and without AlON interlayer

NASA Astrophysics Data System (ADS)

Xu, J. P.; Zhang, X. F.; Li, C. X.; Chan, C. L.; Lai, P. T.

2010-04-01

The electrical properties and high-field reliability of HfTa-based gate-dielectric metal-oxide-semiconductor (MOS) devices with and without AlON interlayer on Ge substrate are investigated. Experimental results show that the MOS capacitor with HfTaON/AlON stack gate dielectric exhibits low interface-state/oxide-charge densities, low gate leakage, small capacitance equivalent thickness (˜1.1 nm), and high dielectric constant (˜20). All of these should be attributed to the blocking role of the ultrathin AlON interlayer against interdiffusions of Ge, Hf, and Ta and penetration of O into the Ge substrate, with the latter effectively suppressing the unintentional formation of unstable poor-quality low- k GeO x and giving a superior AlON/Ge interface. Moreover, incorporation of N into both the interlayer and high- k dielectric further improves the device reliability under high-field stress through the formation of strong N-related bonds.

Ultraviolet GaN photodetectors on Si via oxide buffer heterostructures with integrated short period oxide-based distributed Bragg reflectors and leakage suppressing metal-oxide-semiconductor contacts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Szyszka, A., E-mail: szyszka@ihp-microelectronics.com, E-mail: adam.szyszka@pwr.wroc.pl; Faculty of Microsystem Electronics and Photonics, Wroclaw University of Technology, Janiszewskiego 11/17, 50-372 Wroclaw; Lupina, L.

2014-08-28

Based on a novel double step oxide buffer heterostructure approach for GaN integration on Si, we present an optimized Metal-Semiconductor-Metal (MSM)-based Ultraviolet (UV) GaN photodetector system with integrated short-period (oxide/Si) Distributed Bragg Reflector (DBR) and leakage suppressing Metal-Oxide-Semiconductor (MOS) electrode contacts. In terms of structural properties, it is demonstrated by in-situ reflection high energy electron diffraction and transmission electron microscopy-energy dispersive x-ray studies that the DBR heterostructure layers grow with high thickness homogeneity and sharp interface structures sufficient for UV applications; only minor Si diffusion into the Y{sub 2}O{sub 3} films is detected under the applied thermal growth budget. Asmore » revealed by comparative high resolution x-ray diffraction studies on GaN/oxide buffer/Si systems with and without DBR systems, the final GaN layer structure quality is not significantly influenced by the growth of the integrated DBR heterostructure. In terms of optoelectronic properties, it is demonstrated that—with respect to the basic GaN/oxide/Si system without DBR—the insertion of (a) the DBR heterostructures and (b) dark current suppressing MOS contacts enhances the photoresponsivity below the GaN band-gap related UV cut-off energy by almost up to two orders of magnitude. Given the in-situ oxide passivation capability of grown GaN surfaces and the one order of magnitude lower number of superlattice layers in case of higher refractive index contrast (oxide/Si) systems with respect to classical III-N DBR superlattices, virtual GaN substrates on Si via functional oxide buffer systems are thus a promising robust approach for future GaN-based UV detector technologies.« less

The Effect of Varying Ultrafast Pulse Laser Energies on the Electrical Properties of Reduced Graphene Oxide Sheets in Solution

NASA Astrophysics Data System (ADS)

Ibrahim, Khaled H.; Irannejad, Mehrdad; Wales, Benjamin; Sanderson, Joseph; Musselman, Kevin P.; Yavuz, Mustafa

2018-02-01

Laser treatment of graphene oxide solution among other techniques is a well-established technique for producing reduced graphene sheets. However, production of high-quality ultra-low sheet resistance reduced graphene oxide (rGO) sheets in solution has been a challenge due to their high degree of randomness, defect-rich medium, and lack of controlability. Recent studies lack an in-depth analytic comparison of laser treatment parameters that yield the highest quality rGO sheets with a low defect ratio. Hence, in this study, we implement a comprehensive comparison of laser treatment parameters and their effect on the yielded rGO sheets from an electronic and physical standpoint. Ultra-low sheet resistance graphene oxide sheets were fabricated using ultrafast laser irradiation with different laser pulse energies in the range of 0.25-2 mJ. Laser treatment for 10 min using a pulse energy of 1 mJ resulted in an increase in the defect spacing, accompanied by a large red shift in the optical absorption of the C=C bond, indicating significant restoration of the s p 2 carbon bonds. These enhancements resulted in a significant reduction in the electrical resistance of the rGO flakes (up to 2 orders of magnitude), raising the electron mobility of the films produced using the irradiated graphene oxide a step closer to that of pristine graphene films. From this study, we can also deduce which exposure regimes result in the fabrication of quantum dots and continuous defect-free films.

Kinetic studies of potassium permanganate adsorption by activated carbon and its ability as ethylene oxidation material

NASA Astrophysics Data System (ADS)

Aprilliani, F.; Warsiki, E.; Iskandar, A.

2018-03-01

Generally, ethylene production in many horticultural products has been seen to be detrimental to the quality during storage and distribution process. For this reason, removing ethylene from storage or distribution atmosphere is needed to maintain the quality. One of the technologies that can be applied is the use of potassium permanganate (KMnO4). KMnO4 is an active compound that can be used as an oxidizing agent on ethylene removal process. KMnO4 is not recommended for direct used application. As the result, additional material is required to impregnate the potassium permanganate. The inert materials used are commercial activated carbon. Activated carbon is chosen because it has high surface area. The purpose of this research is to determine kinetics adsorption and oxidation model of ethylene removal material. The kinetics adsorption was determined using the pseudo-first and second-order kinetic models. The data on adsorption process show that the second-order equation is more suitable to express the adsorption process on this research. The analyzing of the ethylene oxidation capacity increased with time until it reaches an optimal value. The ethylene oxidation rate is able to be estimated by the formula r = 0.1967 [C2H4]0.99 [KMnO4]0.01; MSE = 0.44 %. The actual and estimation data of ethylene oxidation show that the model is fitted to describe the actual ethylene oxidation under same experimental conditions.

A Multiplatform Observations of Air Quality in Korea as the Pre-campaign of Korea and US Air Quality (KORUS-AQ) Study.

NASA Astrophysics Data System (ADS)

Park, J. H.; Hong, J.; Hong, Y.; Song, C. K.; Kim, S. K.; Chang, L. S.; Lim, J.; Ahn, J.; Kim, J. Y.; Han, Y. J.; Kim, J.; Park, R.; Lee, G.; Park, J.

2015-12-01

Despite the Korea government's efforts to regulate air pollutant emission for attaining the national air quality standard, current serious dust events and high ozone episodes in summer time remain important societal issues in Korea. In order to make effective policy for air quality attainment, it is contingent upon a thorough understanding of chemical production/loss mechanism of air pollutants and their precursors which drive air quality such as nitrogen oxides (NOX), volatile organic compounds (VOCs), and oxidants (e.g. OH, HO2, RO, RO2, etc.). At present, policy development is constrained by a lack of data for broad suite of chemical species which significantly affect on air quality.During 4 weeks between May and June 2013, the pre-campaign for the Korea and U.S. Air Quality (KORUS-AQ) study took place in multiplatform including fifteen ground sites, one mobile laboratory, and one small air crafts. An integrated research activity covering field observations, chemical transport models, and remote sensing has been intensively conducted. This study was focused on studying photochemistry and nighttime chemistry in urban area and transboundary transport of air pollutants from upwind. Scientific overview and outcomes from the campaign will be presented.

Ionic liquids modified graphene oxide composites: a high efficient adsorbent for phthalates from aqueous solution

PubMed Central

Zhou, Xinguang; Zhang, Yinglu; Huang, Zuteng; Lu, Dingkun; Zhu, Anwei; Shi, Guoyue

2016-01-01

In 2015, more than 30% of erasers were found to contain a PAE content that exceeded the 0.1% limit established by the Quality and Technology Supervision Bureau of Jiangsu Province in China. Thus, strengthening the supervision and regulation of the PAE content in foods and supplies, in particular, remains necessary. Graphene oxide (GO) and its composites have drawn great interests as promising adsorbents for polar and nonpolar compounds. However, GO-based adsorbents are typically restricted by the difficult separation after treatment because of the high pressure in filtration and low density in centrifugation. Herein, a series of novel ionic liquids modified graphene oxide composites (GO-ILs) were prepared as adsorbents for phthalates (PAEs) in eraser samples, which overcame the conventional drawbacks. These novel composites have a combination of the high surface area of graphene oxide and the tunability of the ionic liquids. It is expected that the GO-ILs composites can be used as efficient adsorbents for PAEs from aqueous solution. This work also demonstrated a new technique for GO-based materials applied in sample preparation. PMID:27910926

Ionic liquids modified graphene oxide composites: a high efficient adsorbent for phthalates from aqueous solution

NASA Astrophysics Data System (ADS)

Zhou, Xinguang; Zhang, Yinglu; Huang, Zuteng; Lu, Dingkun; Zhu, Anwei; Shi, Guoyue

2016-12-01

In 2015, more than 30% of erasers were found to contain a PAE content that exceeded the 0.1% limit established by the Quality and Technology Supervision Bureau of Jiangsu Province in China. Thus, strengthening the supervision and regulation of the PAE content in foods and supplies, in particular, remains necessary. Graphene oxide (GO) and its composites have drawn great interests as promising adsorbents for polar and nonpolar compounds. However, GO-based adsorbents are typically restricted by the difficult separation after treatment because of the high pressure in filtration and low density in centrifugation. Herein, a series of novel ionic liquids modified graphene oxide composites (GO-ILs) were prepared as adsorbents for phthalates (PAEs) in eraser samples, which overcame the conventional drawbacks. These novel composites have a combination of the high surface area of graphene oxide and the tunability of the ionic liquids. It is expected that the GO-ILs composites can be used as efficient adsorbents for PAEs from aqueous solution. This work also demonstrated a new technique for GO-based materials applied in sample preparation.

High quality HfO{sub 2}/p-GaSb(001) metal-oxide-semiconductor capacitors with 0.8 nm equivalent oxide thickness

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barth, Michael; Datta, Suman, E-mail: sdatta@engr.psu.edu; Bruce Rayner, G.

2014-12-01

We investigate in-situ cleaning of GaSb surfaces and its effect on the electrical performance of p-type GaSb metal-oxide-semiconductor capacitor (MOSCAP) using a remote hydrogen plasma. Ultrathin HfO{sub 2} films grown by atomic layer deposition were used as a high permittivity gate dielectric. Compared to conventional ex-situ chemical cleaning methods, the in-situ GaSb surface treatment resulted in a drastic improvement in the impedance characteristics of the MOSCAPs, directly evidencing a much lower interface trap density and enhanced Fermi level movement efficiency. We demonstrate that by using a combination of ex-situ and in-situ surface cleaning steps, aggressively scaled HfO{sub 2}/p-GaSb MOSCAP structuresmore » with a low equivalent oxide thickness of 0.8 nm and efficient gate modulation of the surface potential are achieved, allowing to push the Fermi level far away from the valence band edge high up into the band gap of GaSb.« less

Complex oxide thin films for microelectronics

NASA Astrophysics Data System (ADS)

Suvorova, Natalya

The rapid scaling of the device dimensions, namely in metal oxide semiconductor field effect transistor (MOSFET), is reaching its fundamental limit which includes the increase in allowable leakage current due to direct tunneling with decrease of physical thickness of SiO2 gate dielectric. The significantly higher relative dielectric constant (in the range 9--25) of the gate dielectric beyond the 3.9 value of silicon dioxide will allow increasing the physical thickness. Among the choices for the high dielectric constant (K) materials for future generation MOSFET application, barium strontium titanate (BST) and strontium titanate (STO) possess one of the highest attainable K values making them the promising candidates for alternative gate oxide. However, the gate stack engineering does not imply the simple replacement of the SiO2 with the new dielectric. Several requirements should be met for successful integration of a new material. The major one is a production of high level of interface states (Dit) compared to that of SiO 2 on Si. An insertion of a thin SiO2 layer prior the growth of high-K thin film is a simple solution that helps to limit reaction with Si substrate and attains a high quality interface. However, the combination of two thin films reduces the overall K of the dielectric stack. An optimization of the SiO2 underlayer in order to maintain the interface quality yet minimize the effect on K is the focus of this work. The results from our study are presented with emphasis on the key process parameters that improve the dielectric film stack. For in-situ growth characterization of BST and STO films sputter deposited on thermally oxidized Si substrates spectroscopic ellipsometry in combination with time of flight ion scattering and recoil spectrometry have been employed. Studies of material properties have been complemented with analytical electron microscopy. To evaluate the interface quality the electrical characterization has been employed using capacitance-voltage and conductance-voltage measurements. Special attention was given to the extraction of static dielectric constant of BST and STO from the multiple film stack. The K value was found to be sensitive to the input parameters such as dielectric constant and thickness of interface layers.

Analysis of high quality superconducting resonators: consequences for TLS properties in amorphous oxides

NASA Astrophysics Data System (ADS)

Burnett, J.; Faoro, L.; Lindström, T.

2016-04-01

1/f noise caused by microscopic two-level systems (TLS) is known to be very detrimental to the performance of superconducting quantum devices but the nature of these TLS is still poorly understood. Recent experiments with superconducting resonators indicates that interaction between TLS in the oxide at the film-substrate interface is not negligible. Here we present data on the loss and 1/f frequency noise from two different Nb resonators with and without Pt capping and discuss what conclusions can be drawn regarding the properties of TLS in amorphous oxides. We also estimate the concentration and dipole moment of the TLS.

Antibiotics with anaerobic ammonium oxidation in urban wastewater treatment

NASA Astrophysics Data System (ADS)

Zhou, Ruipeng; Yang, Yuanming

2017-05-01

Biofilter process is based on biological oxidation process on the introduction of fast water filter design ideas generated by an integrated filtration, adsorption and biological role of aerobic wastewater treatment process various purification processes. By engineering example, we show that the process is an ideal sewage and industrial wastewater treatment process of low concentration. Anaerobic ammonia oxidation process because of its advantage of the high efficiency and low consumption, wastewater biological denitrification field has broad application prospects. The process in practical wastewater treatment at home and abroad has become a hot spot. In this paper, anammox bacteria habitats and species diversity, and anaerobic ammonium oxidation process in the form of diversity, and one and split the process operating conditions are compared, focusing on a review of the anammox process technology various types of wastewater laboratory research and engineering applications, including general water quality and pressure filtrate sludge digestion, landfill leachate, aquaculture wastewater, monosodium glutamate wastewater, wastewater, sewage, fecal sewage, waste water salinity wastewater characteristics, research progress and application of the obstacles. Finally, we summarize the anaerobic ammonium oxidation process potential problems during the processing of the actual waste water, and proposed future research focus on in-depth study of water quality anammox obstacle factor and its regulatory policy, and vigorously develop on this basis, and combined process optimization.

Method of fabricating optical waveguides by ion implantation doping

DOEpatents

Appleton, Bill R.; Ashley, Paul R.; Buchal, Christopher J.

1989-01-01

A method for fabricating high-quality optical waveguides in optical quality oxide crystals by ion implantation doping and controlled epitaxial recrystallization is provided. Masked LiNbO.sub.3 crystals are implanted with high concentrations of Ti dopant at ion energies of about 350 keV while maintaining the crystal near liquid nitrogen temperature. Ion implantation doping produces an amorphous, Ti-rich nonequilibrium phase in the implanted region. Subsequent thermal annealing in a water-saturated oxygen atmosphere at up to 1000.degree. C. produces solid-phase epitaxial regrowth onto the crystalline substrate. A high-quality single crystalline layer results which incorporates the Ti into the crystal structure at much higher concentrations than is possible by standard diffusion techniques, and this implanted region has excellent optical waveguides properties.

Synthesis and characterization of transparent conductive zinc oxide thin films by sol-gel spin coating method

NASA Astrophysics Data System (ADS)

Winarski, David

Zinc oxide has been given much attention recently as it is promising for various semiconductor device applications. ZnO has a direct band gap of 3.3 eV, high exciton binding energy of 60 meV and can exist in various bulk powder and thin film forms for different applications. ZnO is naturally n-type with various structural defects, which sparks further investigation into the material properties. Although there are many potential applications for this ZnO, an overall lack of understand and control of intrinsic defects has proven difficult to obtain consistent, repeatable results. This work studies both synthesis and characterization of zinc oxide in an effort to produce high quality transparent conductive oxides. The sol-gel spin coating method was used to obtain highly transparent ZnO thin films with high UV absorbance. This research develops a new more consistent method for synthesis of these thin films, providing insight for maintaining quality control for each step in the procedure. A sol-gel spin coating technique is optimized, yielding highly transparent polycrystalline ZnO thin films with tunable electrical properties. Annealing treatment in hydrogen and zinc atmospheres is researched in an effort to increase electrical conductivity and better understand intrinsic properties of the material. These treatment have shown significant effects on the properties of ZnO. Characterization of doped and undoped ZnO synthesized by the sol-gel spin coating method was carried out using scanning electron microscopy, UV-Visible range absorbance, X-ray diffraction, and the Hall Effect. Treatment in hydrogen shows an overall decrease in the number of crystal phases and visible absorbance while zinc seems to have the opposite effect. The Hall Effect has shown that both annealing environments increase the n-type conductivity, yielding a ZnO thin film with a carrier concentration as high as 3.001 x 1021 cm-3.

Current Status and Future Prospects of Copper Oxide Heterojunction Solar Cells.

PubMed

Wong, Terence K S; Zhuk, Siarhei; Masudy-Panah, Saeid; Dalapati, Goutam K

2016-04-07

The current state of thin film heterojunction solar cells based on cuprous oxide (Cu₂O), cupric oxide (CuO) and copper (III) oxide (Cu₄O₃) is reviewed. These p-type semiconducting oxides prepared by Cu oxidation, sputtering or electrochemical deposition are non-toxic, sustainable photovoltaic materials with application potential for solar electricity. However, defects at the copper oxide heterojunction and film quality are still major constraining factors for achieving high power conversion efficiency, η. Amongst the Cu₂O heterojunction devices, a maximum η of 6.1% has been obtained by using pulsed laser deposition (PLD) of Al x Ga 1- x O onto thermal Cu₂O doped with Na. The performance of CuO/n-Si heterojunction solar cells formed by magnetron sputtering of CuO is presently limited by both native oxide and Cu rich copper oxide layers at the heterointerface. These interfacial layers can be reduced by using a two-step sputtering process. A high η of 2.88% for CuO heterojunction solar cells has been achieved by incorporation of mixed phase CuO/Cu₂O nanopowder. CuO/Cu₂O heterojunction solar cells fabricated by electrodeposition and electrochemical doping has a maximum efficiency of 0.64% after surface defect passivation and annealing. Finally, early stage study of Cu₄O₃/GaN deposited on sapphire substrate has shown a photovoltaic effect and an η of ~10 -2 %.

Zinc Oxide-Based Schottky Diode Prepared Using Radio-Frequency Magnetron Cosputtering System

NASA Astrophysics Data System (ADS)

Lai, Bo-Ting; Lee, Ching-Ting; Hong, Jhen-Dong; Yao, Shiau-Lu; Liu, Day-Shan

2010-08-01

The rectifying property of a zinc oxide (ZnO)-based Schottky diode prepared using a radio-frequency (rf) magnetron cosputtering system was improved by enhancing the cosputtered ZnO crystal quality, thereby optimizing the ohmic contact resistance and compensating the Schottky contact surface states. An undoped ZnO layer with a high c-axis orientation and a low internal residual stress was achieved using a postannealing treatment. A homogeneous n-type ZnO-indium tin oxide (ITO) cosputtered film was deposited onto the undoped ZnO layer to optimize the ohmic contact behavior to the Al electrode. The Schottky contact surface of the undoped ZnO layer to the Ni/Au electrode was passivated using an oxygen plasma treatment. Owing to the compensation of the native oxygen vacancies (VO) on the undoped ZnO surface, the leakage current markedly decreased and subsequently led to a quality Schottky diode performance with an ideality factor of 1.23 and a Schottky barrier height of 0.82 eV.

A new generation of zirconia supported metal oxide catalysts for converting low grade renewable feedstocks to biodiesel.

PubMed

Kim, Manhoe; DiMaggio, Craig; Salley, Steven O; Simon Ng, K Y

2012-08-01

A new class of zirconia supported mixed metal oxides (ZnO-TiO(2)-Nd(2)O(3)/ZrO(2) and ZnO-SiO(2)-Yb(2)O(3)/ZrO(2)) has demonstrated the ability to convert low quality, high free fatty acid (FFA) bio-oils into biodiesel. Pelletized catalysts of ZrO(2) supported metal oxides were prepared via a sol-gel process and tested in continuous flow packed bed reactors for up to 6 months. In a single pass, while operating at mild to moderate reaction conditions, 195 °C and 300 psi, these catalysts can perform simultaneous esterification and transesterification reactions on feedstock of 33% FFA and 67% soybean oil to achieve FAME yields higher than 90%. Catalytic activity of the ZrO(2) supported metal oxide catalysts was highly dependent on the metal oxide composition. These heterogeneous catalysts will enable biodiesel manufacturers to avoid problems inherent in homogeneous processes, such as separation and washing, corrosive conditions, and excessive methanol usage. Copyright © 2012 Elsevier Ltd. All rights reserved.

Oxidation of Ethidium using TAML Activators: A Model for High School Research Performed in Partnership with University Scientists

PubMed Central

Pueyo, Natalie C.; Raub, Andrew G.; Jackson, Sean; Metz, Madalyn M.; Mount, Allegra C.; Naughton, Kyle L.; Eaton, Ashley L.; Thomas, Nicole M.; Hastings, Peter; Greaves, John; Blumberg, Bruce; Collins, Terrence J.; Sogo, Steven G.

2013-01-01

A chemical research program at a public high school has been developed. The full-year Advanced Chemical Research class (ACR) in the high school enrolls 20 to 30 seniors each year, engaging them in long-term experimental projects. Through partnerships involving university scientists, ACR high school students have had the opportunity to explore a number of highly sophisticated original research projects. As an example of the quality of experimental work made possible through these high school–university partnerships, this article describes the development of a novel method for the oxidation of ethidium bromide, a mutagen commonly used in molecular biology. Data collected from ACR alumni show that the ACR program is instrumental in encouraging students to pursue careers in scientific fields and in creating life-long problem-solvers. PMID:23585695

Oxidation of Ethidium using TAML Activators: A Model for High School Research Performed in Partnership with University Scientists.

PubMed

Pueyo, Natalie C; Raub, Andrew G; Jackson, Sean; Metz, Madalyn M; Mount, Allegra C; Naughton, Kyle L; Eaton, Ashley L; Thomas, Nicole M; Hastings, Peter; Greaves, John; Blumberg, Bruce; Collins, Terrence J; Sogo, Steven G

2013-03-12

A chemical research program at a public high school has been developed. The full-year Advanced Chemical Research class (ACR) in the high school enrolls 20 to 30 seniors each year, engaging them in long-term experimental projects. Through partnerships involving university scientists, ACR high school students have had the opportunity to explore a number of highly sophisticated original research projects. As an example of the quality of experimental work made possible through these high school-university partnerships, this article describes the development of a novel method for the oxidation of ethidium bromide, a mutagen commonly used in molecular biology. Data collected from ACR alumni show that the ACR program is instrumental in encouraging students to pursue careers in scientific fields and in creating life-long problem-solvers.

Effects of Accelerated Storage on the Quality of Kenaf Seed Oil in Chitosan-Coated High Methoxyl Pectin-Alginate Microcapsules.

PubMed

Leong, Mei-Huan; Tan, Chin-Ping; Nyam, Kar-Lin

2016-10-01

The objective of this research was to study the oxidative stability and antioxidant properties of microencapsulated kenaf (Hibiscus cannabinus L.) seed oil (MKSO) produced by co-extrusion technology upon accelerated storage. The combination of sodium alginate, high methoxyl pectin, and chitosan were used as shell materials. The oxidative stability of the kenaf seed oil was determined by iodine value, peroxide value, p-Anisidine value, total oxidation (TOTOX), thiobarbituric acid reactive substances assay, and free fatty acid content. Total phenolic content, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) cation radical-scavenging assay and 2,2-diphenyl-1-picrylhydrazyl radical scavenging assay were used to examine the antioxidant properties of oils. Oxidative stability tests showed that bulk kenaf seed oil (BKSO) was oxidized significantly higher (P < 0.05) than MKSO. The total increment of TOTOX value of BKSO was 165.93% significantly higher (P < 0.05) than MKSO. Co-extrusion technology has shown to be able to protect kenaf seed oil against lipid oxidation and delay the degradation of natural antioxidants that present in oil during storage. © 2016 Institute of Food Technologists®.

Continuous Polyol Synthesis of Metal and Metal Oxide Nanoparticles Using a Segmented Flow Tubular Reactor (SFTR).

PubMed

Testino, Andrea; Pilger, Frank; Lucchini, Mattia Alberto; Quinsaat, Jose Enrico Q; Stähli, Christoph; Bowen, Paul

2015-06-08

Over the last years a new type of tubular plug flow reactor, the segmented flow tubular reactor (SFTR), has proven its versatility and robustness through the water-based synthesis of precipitates as varied as CaCO3, BaTiO3, Mn(1-x)NixC2O4·2H2O, YBa oxalates, copper oxalate, ZnS, ZnO, iron oxides, and TiO2 produced with a high powder quality (phase composition, particle size, and shape) and high reproducibility. The SFTR has been developed to overcome the classical problems of powder production scale-up from batch processes, which are mainly linked with mass and heat transfer. Recently, the SFTR concept has been further developed and applied for the synthesis of metals, metal oxides, and salts in form of nano- or micro-particles in organic solvents. This has been done by increasing the working temperature and modifying the particle carrying solvent. In this paper we summarize the experimental results for four materials prepared according to the polyol synthesis route combined with the SFTR. CeO2, Ni, Ag, and Ca3(PO4)2 nanoparticles (NPs) can be obtained with a production rate of about 1-10 g per h. The production was carried out for several hours with constant product quality. These findings further corroborate the reliability and versatility of the SFTR for high throughput powder production.

Catalyst-Free Growth of Three-Dimensional Graphene Flakes and Graphene/g-C₃N₄ Composite for Hydrocarbon Oxidation.

PubMed

Chen, Ke; Chai, Zhigang; Li, Cong; Shi, Liurong; Liu, Mengxi; Xie, Qin; Zhang, Yanfeng; Xu, Dongsheng; Manivannan, Ayyakkannu; Liu, Zhongfan

2016-03-22

Mass production of high-quality graphene flakes is important for commercial applications. Graphene microsheets have been produced on an industrial scale by chemical and liquid-phase exfoliation of graphite. However, strong-interaction-induced interlayer aggregation usually leads to the degradation of their intrinsic properties. Moreover, the crystallinity or layer-thickness controllability is not so perfect to fulfill the requirement for advanced technologies. Herein, we report a quartz-powder-derived chemical vapor deposition growth of three-dimensional (3D) high-quality graphene flakes and demonstrate the fabrication and application of graphene/g-C3N4 composites. The graphene flakes obtained after the removal of growth substrates exhibit the 3D curved microstructure, controllable layer thickness, good crystallinity, as well as weak interlayer interactions suitable for preventing the interlayer stacking. Benefiting from this, we achieved the direct synthesis of g-C3N4 on purified graphene flakes to form the uniform graphene/g-C3N4 composite, which provides efficient electron transfer interfaces to boost its catalytic oxidation activity of cycloalkane with relatively high yield, good selectivity, and reliable stability.

Deposition of an Ultraflat Graphene Oxide Nanosheet on Atomically Flat Substrates

NASA Astrophysics Data System (ADS)

Khan, M. Z. H.; Shahed, S. M. F.; Yuta, N.; Komeda, T.

2017-07-01

In this study, graphene oxide (GO) sheets produced in the form of stable aqueous dispersions were deposited on Au (111), freshly cleaved mica, and highly oriented pyrolytic graphite (HOPG) substrates. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) were used to study the presence and distinct contact of GO sheets on the substrates. It was revealed from the topography images that high-quality ultraflat GO monolayer sheets formed on the substrates without distinct cracking/wrinkling or folding. GO sheets with apparent height variation observed by microscopy also indicate ultraflat deposition with clear underlying steps. It was observed that ultrasonication and centrifuge steps prior to deposition were very effective for getting oxidation debris (OD)-free ultraflat single monolayer GO nanosheets onto substrates and that the process depends on the concentration of supplied GO solutions.

High quality fuel gas from biomass pyrolysis with calcium oxide.

PubMed

Zhao, Baofeng; Zhang, Xiaodong; Chen, Lei; Sun, Laizhi; Si, Hongyu; Chen, Guanyi

2014-03-01

The removal of CO2 and tar in fuel gas produced by biomass thermal conversion has aroused more attention due to their adverse effects on the subsequent fuel gas application. High quality fuel gas production from sawdust pyrolysis with CaO was studied in this paper. The results of pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) experiments indicate that the mass ratio of CaO to sawdust (Ca/S) remarkably affects the behavior of sawdust pyrolysis. On the basis of Py-GC/MS results, one system of a moving bed pyrolyzer coupled with a fluid bed combustor has been developed to produce high quality fuel gas. The lower heating value (LHV) of the fuel gas was above 16MJ/Nm(3) and the content of tar was under 50mg/Nm(3), which is suitable for gas turbine application to generate electricity and heat. Therefore, this technology may be a promising route to achieve high quality fuel gas for biomass utilization. Copyright © 2014 Elsevier Ltd. All rights reserved.

Microstructural Influence on Mechanical Properties in Plasma Microwelding of Ti6Al4V Alloy

NASA Astrophysics Data System (ADS)

Baruah, M.; Bag, S.

2016-11-01

The complexity of joining Ti6Al4V alloy enhances with reduction in sheet thickness. The present work puts emphasis on microplasma arc welding (MPAW) of 500-μm-thick Ti6Al4V alloy in butt joint configuration. Using controlled and regulated arc current, the MPAW process is specifically designed to use in joining of thin sheet components over a wide range of process parameters. The weld quality is assessed by carefully controlling the process parameters and by reducing the formation of oxides. The combined effect of welding speed and current on the weld joint properties is evaluated for joining of Ti6Al4V alloy. The macro- and microstructural characterizations of the weldment by optical microscopy as well as the analysis of mechanical properties by microtensile and microhardness test have been performed. The weld joint quality is affected by specifically designed fixture that controls the oxidation of the joint and introduces high cooling rate. Hence, the solidified microstructure of welded specimen influences the mechanical properties of the joint. The butt joint of titanium alloy by MPAW at optimal process parameters is of very high quality, without any internal defects and with minimum residual distortion.

Nitrous oxide emissions from wastewater treatment processes

PubMed Central

Law, Yingyu; Ye, Liu; Pan, Yuting; Yuan, Zhiguo

2012-01-01

Nitrous oxide (N2O) emissions from wastewater treatment plants vary substantially between plants, ranging from negligible to substantial (a few per cent of the total nitrogen load), probably because of different designs and operational conditions. In general, plants that achieve high levels of nitrogen removal emit less N2O, indicating that no compromise is required between high water quality and lower N2O emissions. N2O emissions primarily occur in aerated zones/compartments/periods owing to active stripping, and ammonia-oxidizing bacteria, rather than heterotrophic denitrifiers, are the main contributors. However, the detailed mechanisms remain to be fully elucidated, despite strong evidence suggesting that both nitrifier denitrification and the chemical breakdown of intermediates of hydroxylamine oxidation are probably involved. With increased understanding of the fundamental reactions responsible for N2O production in wastewater treatment systems and the conditions that stimulate their occurrence, reduction of N2O emissions from wastewater treatment systems through improved plant design and operation will be achieved in the near future. PMID:22451112

AIR QUALITY CRITERIA FOR OZONE AND RELATED PHOTOCHEMICAL OXIDANTS

EPA Science Inventory

The Clean Air Act requires periodic (5-year) update revision of criteria and National Ambient Air Quality Standards (NAAQS) for Ozone. The previous revision of the criteria contained in the Air Quality Criteria Document (AQCD) for Ozone and Related Photochemical Oxidants was co...

Changes during storage of quality parameters and in vitro antioxidant activity of extra virgin monovarietal oils obtained with two extraction technologies.

PubMed

Fadda, C; Del Caro, A; Sanguinetti, A M; Urgeghe, P P; Vacca, V; Arca, P P; Piga, A

2012-10-01

Extraction technology has a great effect on quality of olive oils. This paper studied 18 months of storage of two Sardinian extra virgin monovarietal oils obtained with a traditional and with a low oxidative stress technology. Oil samples were subjected to the following chemical analyses: acidity, peroxide value, ultraviolet light absorption K₂₃₂ and K₂₇₀, carotenoids, chlorophylls, tocopherols and total polyphenols. The antioxidant capacity of oils, polyphenol extract and oil extract (remaining after polyphenol extraction) was also determined as radical scavenging activity. The results show that both extraction technologies resulted in minor changes in legal and quality indices during storage, due surely to the high quality of the oils as well as to the very good storage conditions used. Oils obtained with the low oxidative stress technology showed lower peroxide value and acidity and resulted in up to 103% higher total polyphenol content as well as increased radical-scavenging activity, with respect to oils obtained with the traditional technology. Copyright © 2012 Elsevier Ltd. All rights reserved.

Influence of a Boron Precursor on the Growth and Optoelectronic Properties of Electrodeposited Zinc Oxide Thin Film.

PubMed

Tsin, Fabien; Thomere, Angélica; Bris, Arthur Le; Collin, Stéphane; Lincot, Daniel; Rousset, Jean

2016-05-18

Highly transparent and conductive materials are required for many industrial applications. One of the interesting features of ZnO is the possibility to dope it using different elements, hence improving its conductivity. Results concerning the zinc oxide thin films electrodeposited in a zinc perchlorate medium containing a boron precursor are presented in this study. The addition of boron to the electrolyte leads to significant effects on the morphology and crystalline structure as well as an evolution of the optical properties of the material. Varying the concentration of boric acid from 0 to 15 mM strongly improves the compactness of the deposit and increases the band gap from 3.33 to 3.45 eV. Investigations were also conducted to estimate and determine the influence of boric acid on the electrical properties of the ZnO layers. As a result, no doping effect effect by boron was demonstrated. However, the role of boric acid on the material quality has also been proven and discussed. Boric acid strongly contributes to the growth of high quality electrodeposited zinc oxide. The high doping level of the film can be attributed to the perchlorate ions introduced in the bath. Finally, a ZnO layer electrodeposited in a boron rich electrolyte was tested as front contact of a Cu(In, Ga)(S, Se)2 based solar cell. An efficiency of 12.5% was measured with a quite high fill factor (>70%) which confirms the high conductivity of the ZnO thin film.

Pastes: what do they contain? How do they work?

PubMed

Juch, R D; Rufli, T; Surber, C

1994-01-01

Pastes are semisolid stiff preparations containing a high proportion of finely powdered material. Powders such as zinc oxide, titanium dioxide, starch, kaolin or talc are incorporated in high concentrations into a preferably lipophilic, greasy vehicle. A clinically distinctive feature which is generally attributed to pastes is the quality to absorb exudates by nature of the powder or other absorptive components. Reviewing the various pharmacopoeias serious doubts arise from the various formulas of pastes and their absorptive features. The zinc oxide pastes of the USP XXII, the DAB 10 and BP 88 (US, German and British pharmacopoeias). are composed of petrolatum, zinc oxide and starch. Petrolatum, a highly lipophilic, water-immiscible vehicle surrounds the powder particles preventing any absorption of water or exudates. The goal of our investigation was to test a simple experimental setting to characterize the clinically important absorptive feature of powders and pastes. The absorptive features of the powders were determined by the method of Enslin. The absorptive features of the paste preparations were calculated from the weight difference between the paste preparation before and after incubation with water using a simple standardized procedure. The absorptive features of titanium dioxide, zinc oxide, kaolin, corn starch and methylcellulose powder in pharmacopoeia quality were determined. Zinc oxide and kaolin powder showed the highest absorption of 1,000 mg water/g powder (100%). The water absorption of corn starch and titanium dioxide was 700 and 450 mg/g powder, respectively. The absorptive features of a series of paste preparations were studied in a simple experimental setting. The data show that two-phase pastes consisting of two immiscible components, one (the dispersed or inner phase; powder) being suspended in the other (the continuous or outer phase; lipophilic vehicle), have no absorptive features. In contrast, three-phase pastes consisting of a hydrophilic two-phase emulsion with high concentrations of incorporated powder (cream pastes) show considerable water uptake. We conclude that the classical two-phase pastes such as the zinc oxide pastes have no absorptive features. On the contrary, these formulations are highly occlusive. Therefore lipophilic pastes are only indicated when protection of intact skin against aggressive body exudates and humidity is required. The hydrophilic three-phase pastes or cream pastes show considerable water uptake and fulfil common expectations of pastes to dry the skin.

The important role of water in growth of monolayer transition metal dichalcogenides

NASA Astrophysics Data System (ADS)

Kastl, Christoph; Chen, Christopher T.; Kuykendall, Tevye; Shevitski, Brian; Darlington, Thomas P.; Borys, Nicholas J.; Krayev, Andrey; Schuck, P. James; Aloni, Shaul; Schwartzberg, Adam M.

2017-06-01

2D transition metal dichalcogenides (TMDs) are commonly grown by chemical vapor deposition using transition metal oxides as solid precursors. Despite the widespread use of this technique, challenges in reproducibility, coverage, and material quality are pervasive, suggestive of unknown and uncontrolled process parameters. In this communication, we demonstrate the impact of water vapor on this growth process. Our results show a direct correlation between gas phase water content and the morphology of TMD films. In particular, we show that the presence of water enhances volatilization, and therefore the vapor transport of tungsten and molybdenum oxide. Surprisingly, we find that water not only plays an important role in volatilization but is also compatible with TMD growth. In fact, carefully controlled humidity can consistently produce high quality, luminescent materials.

Process for growing a film epitaxially upon a MGO surface and structures formed with the process

DOEpatents

McKee, Rodney Allen; Walker, Frederick Joseph

1998-01-01

A process and structure wherein optical quality perovskites, such as BaTiO.sub.3 or SrTiO.sub.3, are grown upon a single crystal MgO substrate involves the epitaxial build up of alternating planes of TiO.sub.2 and metal oxide wherein the first plane grown upon the MgO substrate is a plane of TiO.sub.2. The layering sequence involved in the film build up reduces problems which would otherwise result from the interfacial electrostatics at the first atomic layers, and these oxides can be stabilized as commensurate thin films at a unit cell thickness or grown with high crystal quality to thicknesses of 0.5-0.7 .mu.m for optical device applications.

Nitrous Oxide During Labor: Maternal Satisfaction Does Not Depend Exclusively on Analgesic Effectiveness.

PubMed

Richardson, Michael G; Lopez, Brandon M; Baysinger, Curtis L; Shotwell, Matthew S; Chestnut, David H

2017-02-01

Evidence on the analgesic effectiveness of nitrous oxide for labor pain is limited. Even fewer studies have looked at patient satisfaction. Although nitrous oxide appears less effective than neuraxial analgesia, it is unclear whether labor analgesic effectiveness is the most important factor in patient satisfaction. We sought to compare the relationship between analgesic effectiveness and patient satisfaction with analgesia in women who delivered vaginally using nitrous oxide, neuraxial analgesia (epidural or combined spinal-epidural [CSE]), or both (neuraxial after a trial of nitrous oxide). A standardized survey was recorded on the first postpartum day for all women who received anesthetic care for labor and delivery. Data were queried for women who delivered vaginally with nitrous oxide and/or neuraxial labor analgesia over a 34-month period in 2011 to 2014. Parturients with complete data for analgesia quality and patient satisfaction were included. Analgesia and satisfaction scores were grouped into 8 to 10 high, 5 to 7 intermediate, and 0 to 4 low. These scores were compared with the use of ordinal logistic regression across 3 groups: nitrous oxide alone, epidural or CSE alone, or nitrous oxide followed by neuraxial (epidural or CSE) analgesia. A total of 6507 women received anesthesia care and delivered vaginally. Complete data were available for 6242 (96%) women; 5261 (81%) chose neuraxial analgesia and 1246 (19%) chose nitrous oxide. Of the latter, 753 (60%) went on to deliver with nitrous oxide alone, and 493 (40%) switched to neuraxial analgesia. Most parturients who received neuraxial analgesia (>90%) reported high analgesic effectiveness. Those who used nitrous oxide alone experienced variable analgesic effectiveness, with only one-half reporting high effectiveness. Among all women who reported poor analgesia effectiveness (0-4; n = 257), those who received nitrous oxide alone were more likely to report high satisfaction (8-10) than women who received epidural analgesia alone (OR 2.5; 95% CI 1.4-4.5; P = .002). Women who reported moderate analgesia (5-7) and received nitrous oxide only were more likely to report high satisfaction compared with the other groups. Among women who reported a high level of analgesic effectiveness, satisfaction with anesthesia was high and not different among groups. Patients who received nitrous oxide alone were as likely to express satisfaction with anesthesia care as those who received neuraxial analgesia, even though they were less likely to report excellent analgesia. Although pain relief contributes to the satisfaction with labor analgesia care, our results suggest that analgesia is not the only contributor to maternal satisfaction.

Low-temperature high-mobility amorphous IZO for silicon heterojunction solar cells

DOE PAGES

Morales-Masis, Monica; Martin De Nicolas, Silvia; Holovsky, Jakub; ...

2015-07-13

Parasitic absorption in the transparent conductive oxide (TCO) front electrode is one of the limitations of silicon heterojunction (SHJ) solar cells efficiency. To avoid such absorption while retaining high conductivity, TCOs with high electron mobility are preferred over those with high carrier density. Here, we demonstrate improved SHJ solar cell efficiencies by applying high-mobility amorphous indium zinc oxide (a-IZO) as the front TCO. We sputtered a-IZO at low substrate temperature and low power density and investigated the optical and electrical properties, as well as subband tail formation-quantified by the Urbach energy (E U)-as a function of the sputtering oxygen partialmore » pressure. We obtain an E U as low as 128 meV for films with the highest Hall mobility of 60 cm 2/Vs. When comparing the performance of a-IZO films with indium tin oxide (ITO) and hydrogenated indium oxide (IO:H), we find that IO:H (115 cm 2/Vs) exhibits a similar E U of 130 meV, while ITO (25 cm 2/Vs) presents a much larger E U of up to 270 meV. The high film quality, indicated by the low E U, the high mobility, and low free carrier absorption of the developed a-IZO electrodes, result in a significant current improvement, achieving conversion efficiencies over 21.5%, outperforming those with standard ITO.« less

Identification of the iron oxidation state and coordination geometry in iron oxide- and zeolite-based catalysts using pre-edge XAS analysis.

PubMed

Boubnov, Alexey; Lichtenberg, Henning; Mangold, Stefan; Grunwaldt, Jan Dierk

2015-03-01

Analysis of the oxidation state and coordination geometry using pre-edge analysis is attractive for heterogeneous catalysis and materials science, especially for in situ and time-resolved studies or highly diluted systems. In the present study, focus is laid on iron-based catalysts. First a systematic investigation of the pre-edge region of the Fe K-edge using staurolite, FePO4, FeO and α-Fe2O3 as reference compounds for tetrahedral Fe(2+), tetrahedral Fe(3+), octahedral Fe(2+) and octahedral Fe(3+), respectively, is reported. In particular, high-resolution and conventional X-ray absorption spectra are compared, considering that in heterogeneous catalysis and material science a compromise between high-quality spectroscopic data acquisition and simultaneous analysis of functional properties is required. Results, which were obtained from reference spectra acquired with different resolution and quality, demonstrate that this analysis is also applicable to conventionally recorded pre-edge data. For this purpose, subtraction of the edge onset is preferentially carried out using an arctangent and a first-degree polynomial, independent of the resolution and quality of the data. For both standard and high-resolution data, multiplet analysis of pre-edge features has limitations due to weak transitions that cannot be identified. On the other hand, an arbitrary empirical peak fitting assists the analysis in that non-local transitions can be isolated. The analysis of the oxidation state and coordination geometry of the Fe sites using a variogram-based method is shown to be effective for standard-resolution data and leads to the same results as for high-resolution spectra. This method, validated by analysing spectra of reference compounds and their well defined mixtures, is finally applied to track structural changes in a 1% Fe/Al2O3 and a 0.5% Fe/BEA zeolite catalyst during reduction in 5% H2/He. The results, hardly accessible by other techniques, show that Fe(3+) is transformed into Fe(2+), while the local Fe-O coordination number of 4-5 is maintained, suggesting that the reduction involves a rearrangement of the oxygen neighbours rather than their removal. In conclusion, the variogram-based analysis of Fe K-edge spectra proves to be very useful in catalysis research.

Lightning NOx and Impacts on Air Quality

NASA Technical Reports Server (NTRS)

Murray, Lee T.

2016-01-01

Lightning generates relatively large but uncertain quantities of nitrogen oxides, critical precursors for ozone and hydroxyl radical (OH), the primary tropospheric oxidants. Lightning nitrogen oxide strongly influences background ozone and OH due to high ozone production efficiencies in the free troposphere, effecting small but non-negligible contributions to surface pollutant concentrations. Lightning globally contributes 3-4 ppbv of simulated annual-mean policy-relevant background (PRB) surface ozone, comprised of local, regional, and hemispheric components, and up to 18 ppbv during individual events. Feedbacks via methane may counter some of these effects on decadal time scales. Lightning contributes approximately 1 percent to annual-mean surface particulate matter, as a direct precursor and by promoting faster oxidation of other precursors. Lightning also ignites wildfires and contributes to nitrogen deposition. Urban pollution influences lightning itself, with implications for regional lightning-nitrogen oxide production and feedbacks on downwind surface pollution. How lightning emissions will change in a warming world remains uncertain.

Air Quality Criteria for Ozone and Related Photochemical Oxidants (Final Report, 2006)

EPA Science Inventory

In February 2006, EPA released the final document, Air Quality Criteria for Ozone and Other Photochemical Oxidants. Tropospheric or surface-level ozone (O3) is one of six major air pollutants regulated by National Ambient Air Quality Standards (NAAQS) under the U.S...

Chemical bath deposited (CBD) CuO thin films on n-silicon substrate for electronic and optical applications: Impact of growth time

NASA Astrophysics Data System (ADS)

Sultana, Jenifar; Paul, Somdatta; Karmakar, Anupam; Yi, Ren; Dalapati, Goutam Kumar; Chattopadhyay, Sanatan

2017-10-01

Thin film of p-type cupric oxide (p-CuO) is grown on silicon (n-Si) substrate by using chemical bath deposition (CBD) technique and a precise control of thickness from 60 nm to 178 nm has been achieved. The structural properties and stoichiometric composition of the grown films are observed to depend significantly on the growth time. The chemical composition, optical properties, and structural quality are investigated in detail by employing XRD, ellipsometric measurements and SEM images. Also, the elemental composition and the oxidation states of Cu and O in the grown samples have been studied in detail by XPS measurements. Thin film of 110 nm thicknesses exhibited the best performance in terms of crystal quality, refractive index, dielectric constant, band-gap, and optical properties. The study suggests synthesis route for developing high quality CuO thin film using CBD method for electronic and optical applications.

The role of gas in determining image quality and resolution during in situ scanning transmission electron microscopy experiments

DOE PAGES

Zhu, Yuanyuan; Browning, Nigel D.

2017-05-24

As gas-solid heterogeneous catalytic reactions are molecular in nature, a full mechanistic understanding of the process requires atomic scale characterization under realistic operating conditions. While atomic resolution imaging has become a routine in modern high-vacuum (scanning) transmission electron microscopy ((S)TEM), both image quality and resolution nominally degrade when reaction gases are introduced. In this work, we systematically assess the effects of different gases at various pressures on the quality and resolution of images obtained at room temperature in the annular dark field STEM imaging mode using a differentially pumped (DP) gas cell. This imaging mode is largely free from inelasticmore » scattering effects induced by the presence of gases and retains good imaging properties over a wide range of gas mass/pressures. Furthermore, we demonstrate the application of the ESTEM with atomic resolution images of a complex oxide alkane oxidation catalyst MoVNbTeOx (M1) immersed in light and heavy gas environments.« less

75 FR 34095 - Application(s) for Duty-Free Entry of Scientific Instruments

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-16

...: University of Minnesota (Dept. of Chemical Engineering and Materials Science), 151 Amundson Hall, 421... Scientific Instruments Pursuant to Section 6(c) of the Educational, Scientific and Cultural Materials... coatings, of very high crystalline quality materials known as complex oxides. A pertinent characteristic of...

Field-analysis of potable water quality and ozone efficiency in ozone-assisted biological filtration systems for surface water treatment.

PubMed

Zanacic, Enisa; Stavrinides, John; McMartin, Dena W

2016-11-01

Potable water treatment in small communities is challenging due to a complexity of factors starting with generally poor raw water sources, a smaller tax and consumption base that limit capital and operating funds, and culminating in what is typically a less sophisticated and robust water treatment plant for production and delivery of safe, high quality potable water. The design and optimization of modular ozone-assisted biological filtration systems can address some of these challenges. In surface water treatment, the removal of organic matter (e.g., dissolved organic carbon - DOC), inorganic nutrients and other exposure-related contaminants (e.g., turbidity and dissolved solids) from the raw water source is essential. Thus, a combination of chemical and biological oxidation processes can produce an effective and efficient water treatment plant design that is also affordable and robust. To that end, the ozone-assisted biological filtration water treatment plants in two communities were evaluated to determine the efficacy of oxidation and contaminant removal processes. The results of testing for in-field system performance indicate that plant performance is particularly negatively impacted by high alkalinity, high organics loading, and turbidity. Both bicarbonate and carbonate alkalinity were observed to impede ozone contact and interaction with DOC, resulting in lower than anticipated DOC oxidation efficiency and bioavailability. The ozone dosage at both water treatment plants must be calculated on a more routine basis to better reflect both the raw water DOC concentration and presence of alkalinities to ensure maximized organics oxidation and minimization of trihalomethanes production. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Inkjet printing of metal-oxide-based transparent thin-film capacitors

NASA Astrophysics Data System (ADS)

Matavž, A.; Malič, B.; Bobnar, V.

2017-12-01

We report on the inkjet printing of transparent, thin-film capacitors (TTFCs) composed of indium-zinc-oxide electrodes and a tantalum-oxide-based dielectric on glass substrates. The printing parameters were adapted for the sequential deposition of functional layers, resulting in approximately 100-nm-thick transparent capacitors with a uniform thickness. The relatively high electrical resistivity of the electrodes is reflected in the frequency dispersive dielectric behaviour, which is explained in terms of an equivalent circuit. The resistivity of the electrode strongly decreases with the number of printing passes; consequently, any misalignment of the printed layers is detected in the measured response. At low frequency, the TTFCs show a stable intrinsic dielectric response and a high capacitance density of ˜280 nF/cm2. The good dielectric performance as well as the low leakage-current density (8 × 10-7 A/cm2 at 1 MV cm-1) of our capacitors indicates that inkjet printing can be used to produce all-printed, high-quality electrical devices.

Fenton oxidation to remediate PAHs in contaminated soils: A critical review of major limitations and counter-strategies.

PubMed

Usman, M; Hanna, K; Haderlein, S

2016-11-01

Fenton oxidation constitutes a viable remediation strategy to remove polycyclic aromatic hydrocarbons (PAHs) in contaminated soils. This review is intended to illustrate major limitations associated with this process like acidification, PAH unavailability, and deterioration of soil quality along with associated factors, followed by a critical description of various developments to overcome these constraints. Considering the limitation that its optimal pH is around 3, traditional Fenton treatment could be costly, impractical in soil due to the high buffering capacity of soils and associated hazardous effects. Use of various chelating agents (organic or inorganic) allowed oxidation at circumneutral pH but factors like higher oxidant demand, cost and toxicity should be considered. Another alternative is the use of iron minerals that can catalyze Fenton-like oxidation over a wide range of pH, but mobility of these particles in soils (i.e. saturated and unsaturated zones) should be investigated prior to in-situ applications. The PAH-unavailability is the crucial limitation hindering their effective degradation. Research data is compiled describing various strategies to address this issue like the use of availability enhancement agents, extraction or thermal pretreatment. Last section of this review is devoted to describe the effects of various developments in Fenton treatment onto soil quality and native microbiota. Finally, research gaps are discussed to suggest future directions in context of applying Fenton oxidation to remediate contaminated soils. Copyright © 2016 Elsevier B.V. All rights reserved.

Highly insulating ferromagnetic cobaltite heterostructures

DOE PAGES

Choi, Woo Seok; Kang, Kyeong Tae; Jeen, Hyoungjeen; ...

2017-04-02

Ferromagnetic insulators are rather rare but possess great technological potential in, for example, spintronics. Individual control of ferromagnetic properties and electronic transport provides a useful design concept of multifunctional oxide heterostructures. We studied the close correlation among the magnetism, atomic structure, and electronic structure of oxide heterostructures composed of the ferromagnetic perovskite LaCoO 3 and the antiferromagnetic brownmillerite SrCoO 2.5 epitaxial thin film layers. By reversing the stacking sequence of the two layers, we could individually modify the electric resistance and saturation magnetic moment. Lastly, the ferromagnetic insulating behavior in the heterostructures was understood in terms of the electronic reconstructionmore » at the oxide surface/interfaces and crystalline quality of the constituent layers.« less

Highly insulating ferromagnetic cobaltite heterostructures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Choi, Woo Seok; Kang, Kyeong Tae; Jeen, Hyoungjeen

Ferromagnetic insulators are rather rare but possess great technological potential in, for example, spintronics. Individual control of ferromagnetic properties and electronic transport provides a useful design concept of multifunctional oxide heterostructures. We studied the close correlation among the magnetism, atomic structure, and electronic structure of oxide heterostructures composed of the ferromagnetic perovskite LaCoO 3 and the antiferromagnetic brownmillerite SrCoO 2.5 epitaxial thin film layers. By reversing the stacking sequence of the two layers, we could individually modify the electric resistance and saturation magnetic moment. Lastly, the ferromagnetic insulating behavior in the heterostructures was understood in terms of the electronic reconstructionmore » at the oxide surface/interfaces and crystalline quality of the constituent layers.« less

Oxide and hydrogen capped ultrasmall blue luminescent Si nanoparticles

NASA Astrophysics Data System (ADS)

Belomoin, Gennadiy; Therrien, Joel; Nayfeh, Munir

2000-08-01

We dispersed electrochemical etched silicon into a colloid of ultrasmall ultrabright Si nanoparticles. Direct imaging using transmission electron microscopy shows particles of ˜1 nm in diameter, and infrared and electron photospectroscopy show that they are passivated with hydrogen. Under 350 nm excitation, the luminescence is dominated by an extremely strong blue band at 390 nm. We replace hydrogen by a high-quality ultrathin surface oxide cap by self-limiting oxidation in H2O2. Upon capping, the excitation efficiency drops, but only by a factor of 2, to an efficiency still two-fold larger than that of fluorescein. Although of slightly lower brightness, capped Si particles have superior biocompatability, an important property for biosensing applications.

Spin Seebeck effect in insulating epitaxial γ-Fe2O3 thin films

NASA Astrophysics Data System (ADS)

Jiménez-Cavero, P.; Lucas, I.; Anadón, A.; Ramos, R.; Niizeki, T.; Aguirre, M. H.; Algarabel, P. A.; Uchida, K.; Ibarra, M. R.; Saitoh, E.; Morellón, L.

2017-02-01

We report the fabrication of high crystal quality epitaxial thin films of maghemite (γ-Fe2O3), a classic ferrimagnetic insulating iron oxide. Spin Seebeck effect (SSE) measurements in γ-Fe2O3/Pt bilayers as a function of sample preparation conditions and temperature yield a SSE coefficient of 0.5(1) μV/K at room temperature. Dependence on temperature allows us to estimate the magnon diffusion length in maghemite to be in the range of tens of nanometers, in good agreement with that of conducting iron oxide magnetite (Fe3O4), establishing the relevance of spin currents of magnonic origin in magnetic iron oxides.

High optical quality GaN nanopillar arrays

NASA Astrophysics Data System (ADS)

Wang, Y. D.; Chua, S. J.; Tripathy, S.; Sander, M. S.; Chen, P.; Fonstad, C. G.

2005-02-01

GaN nanopillar arrays have been fabricated by inductively coupled plasma etching of GaN films using anodic aluminum oxide film as an etch mask. The average diameter and length of these pillars are 60-65nm and 350-400nm, respectively. Ultraviolet microphotoluminescence measurements indicate high photoluminescence intensity and stress relaxation in these GaN nanopillars as compared to the starting epitaxial GaN films. Evidence of good crystalline quality is also observed by micro-Raman measurements, wherein a redshift of the E2high mode from GaN nanopillars suggests partial relaxation of the compressive strain. In addition, breakdown of the polarization selection rules led to the appearance of symmetry-forbidden and quasipolar modes.

Current Status and Future Prospects of Copper Oxide Heterojunction Solar Cells

PubMed Central

Wong, Terence K. S.; Zhuk, Siarhei; Masudy-Panah, Saeid; Dalapati, Goutam K.

2016-01-01

The current state of thin film heterojunction solar cells based on cuprous oxide (Cu2O), cupric oxide (CuO) and copper (III) oxide (Cu4O3) is reviewed. These p-type semiconducting oxides prepared by Cu oxidation, sputtering or electrochemical deposition are non-toxic, sustainable photovoltaic materials with application potential for solar electricity. However, defects at the copper oxide heterojunction and film quality are still major constraining factors for achieving high power conversion efficiency, η. Amongst the Cu2O heterojunction devices, a maximum η of 6.1% has been obtained by using pulsed laser deposition (PLD) of AlxGa1−xO onto thermal Cu2O doped with Na. The performance of CuO/n-Si heterojunction solar cells formed by magnetron sputtering of CuO is presently limited by both native oxide and Cu rich copper oxide layers at the heterointerface. These interfacial layers can be reduced by using a two-step sputtering process. A high η of 2.88% for CuO heterojunction solar cells has been achieved by incorporation of mixed phase CuO/Cu2O nanopowder. CuO/Cu2O heterojunction solar cells fabricated by electrodeposition and electrochemical doping has a maximum efficiency of 0.64% after surface defect passivation and annealing. Finally, early stage study of Cu4O3/GaN deposited on sapphire substrate has shown a photovoltaic effect and an η of ~10−2%. PMID:28773398

Growth control of the oxidation state in vanadium oxide thin films

DOE PAGES

Lee, Shinbuhm; Meyer, Tricia L.; Park, Sungkyun; ...

2014-12-05

Precise control of the chemical valence or oxidation state of vanadium in vanadium oxide thin films is highly desirable for not only fundamental research, but also technological applications that utilize the subtle change in the physical properties originating from the metalinsulator transition (MIT) near room temperature. However, due to the multivalent nature of vanadium and the lack of a good understanding on growth control of the oxidation state, stabilization of phase pure vanadium oxides with a single oxidation state is extremely challenging. Here, we systematically varied the growth conditions to clearly map out the growth window for preparing phase puremore » epitaxial vanadium oxides by pulsed laser deposition for providing a guideline to grow high quality thin films with well-defined oxidation states of V₂⁺²O₃, V⁺⁴O₂, and V₂⁺⁵O₅. A well pronounced MIT was only observed in VO₂ films grown in a very narrow range of oxygen partial pressure P(O₂). The films grown either in lower (< 10 mTorr) or higher P(O₂) (> 25 mTorr) result in V₂O₃ and V₂O₅ phases, respectively, thereby suppressing the MIT for both cases. We have also found that the resistivity ratio before and after the MIT of VO₂ thin films can be further enhanced by one order of magnitude when the films are further oxidized by post-annealing at a well-controlled oxidizing ambient. This result indicates that stabilizing vanadium into a single valence state has to compromise with insufficient oxidation of an as grown thin film and, thereby, a subsequent oxidation is required for an 3 improved MIT behavior.« less

Growth control of the oxidation state in vanadium oxide thin films

NASA Astrophysics Data System (ADS)

Lee, Shinbuhm; Meyer, Tricia L.; Park, Sungkyun; Egami, Takeshi; Lee, Ho Nyung

2014-12-01

Precise control of the chemical valence or oxidation state of vanadium in vanadium oxide thin films is highly desirable for not only fundamental research but also technological applications that utilize the subtle change in the physical properties originating from the metal-insulator transition (MIT) near room temperature. However, due to the multivalent nature of vanadium and the lack of a good understanding on growth control of the oxidation state, stabilization of phase pure vanadium oxides with a single oxidation state is extremely challenging. Here, we systematically varied the growth conditions to clearly map out the growth window for preparing phase pure epitaxial vanadium oxides by pulsed laser deposition for providing a guideline to grow high quality thin films with well-defined oxidation states of V2 + 3 O 3 , V + 4 O 2 , and V2 + 5 O 5 . A well pronounced MIT was only observed in VO2 films grown in a very narrow range of oxygen partial pressure P(O2). The films grown either in lower (<10 mTorr) or higher P(O2) (>25 mTorr) result in V2O3 and V2O5 phases, respectively, thereby suppressing the MIT for both cases. We have also found that the resistivity ratio before and after the MIT of VO2 thin films can be further enhanced by one order of magnitude when the films are further oxidized by post-annealing at a well-controlled oxidizing ambient. This result indicates that stabilizing vanadium into a single valence state has to compromise with insufficient oxidation of an as grown thin film and, thereby, a subsequent oxidation is required for an improved MIT behavior.

Growth control of the oxidation state in vanadium oxide thin films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Shinbuhm; Meyer, Tricia L.; Lee, Ho Nyung, E-mail: hnlee@ornl.gov

2014-12-01

Precise control of the chemical valence or oxidation state of vanadium in vanadium oxide thin films is highly desirable for not only fundamental research but also technological applications that utilize the subtle change in the physical properties originating from the metal-insulator transition (MIT) near room temperature. However, due to the multivalent nature of vanadium and the lack of a good understanding on growth control of the oxidation state, stabilization of phase pure vanadium oxides with a single oxidation state is extremely challenging. Here, we systematically varied the growth conditions to clearly map out the growth window for preparing phase puremore » epitaxial vanadium oxides by pulsed laser deposition for providing a guideline to grow high quality thin films with well-defined oxidation states of V{sub 2}{sup +3}O{sub 3}, V{sup +4}O{sub 2}, and V{sub 2}{sup +5}O{sub 5}. A well pronounced MIT was only observed in VO{sub 2} films grown in a very narrow range of oxygen partial pressure P(O{sub 2}). The films grown either in lower (<10 mTorr) or higher P(O{sub 2}) (>25 mTorr) result in V{sub 2}O{sub 3} and V{sub 2}O{sub 5} phases, respectively, thereby suppressing the MIT for both cases. We have also found that the resistivity ratio before and after the MIT of VO{sub 2} thin films can be further enhanced by one order of magnitude when the films are further oxidized by post-annealing at a well-controlled oxidizing ambient. This result indicates that stabilizing vanadium into a single valence state has to compromise with insufficient oxidation of an as grown thin film and, thereby, a subsequent oxidation is required for an improved MIT behavior.« less

Enrichment of Animal Diets with Essential Oils—A Great Perspective on Improving Animal Performance and Quality Characteristics of the Derived Products

PubMed Central

Simitzis, Panagiotis E.

2017-01-01

Food industry operates in a competitive market and is continually facing challenges to retain or even increase its market share. Consistent high-quality animal products are required to maintain consumer confidence and consumption. Enrichment of foods with bioactive compounds such as the essential oils appears to improve quality characteristics of the derived products and protects consumers against oxidation and bacterial spoilage effects. Synthetic additives are nowadays questioned due to their suspected carcinogenic potential, and therefore extensive research has been undertaken to identify safe and efficient alternatives. Aromatic plants and their respective essential oils belong to natural products and are generally used in pig, poultry, rabbit and ruminant nutrition. The inclusion of essential oils in livestock diets is nowadays becoming a common practice, since dietary supplementation has been proven a simple and convenient strategy to effectively inhibit the oxidative reactions or microbial spoilage at their localized sites. A wide range of essential oils contain bioactive compounds that have the potential to act as multifunctional feed supplements for animals including effects on growth performance, digestive system, pathogenic bacterial growth and lipid oxidation. However, further studies are needed to clarify their exact action and establish their regular use in animal production. PMID:28930250

Process for growing a film epitaxially upon an oxide surface and structures formed with the process

DOEpatents

McKee, Rodney Allen; Walker, Frederick Joseph

1998-01-01

A process and structure wherein a film comprised of a perovskite or a spinel is built epitaxially upon a surface, such as an alkaline earth oxide surface, involves the epitaxial build up of alternating constituent metal oxide planes of the perovskite or spinel. The first layer of metal oxide built upon the surface includes a metal element which provides a small cation in the crystalline structure of the perovskite or spinel, and the second layer of metal oxide built upon the surface includes a metal element which provides a large cation in the crystalline structure of the perovskite or spinel. The layering sequence involved in the film build up reduces problems which would otherwise result from the interfacial electrostatics at the first atomic layers, and these oxides can be stabilized as commensurate thin films at a unit cell thickness or grown with high crystal quality to thicknesses of 0.5-0.7 .mu.m for optical device applications.

Process for growing a film epitaxially upon an oxide surface and structures formed with the process

DOEpatents

McKee, Rodney A.; Walker, Frederick J.

1995-01-01

A process and structure wherein a film comprised of a perovskite or a spinel is built epitaxially upon a surface, such as an alkaline earth oxide surface, involves the epitaxial build up of alternating constituent metal oxide planes of the perovskite or spinel. The first layer of metal oxide built upon the surface includes a metal element which provides a small cation in the crystalline structure of the perovskite or spinel, and the second layer of metal oxide built upon the surface includes a metal element which provides a large cation in the crystalline structure of the perovskite or spinel. The layering sequence involved in the film build up reduces problems which would otherwise result from the interfacial electrostatics at the first atomic layers, and these oxides can be stabilized as commensurate thin films at a unit cell thickness or grown with high crystal quality to thicknesses of 0.5-0.7 .mu.m for optical device applications.

Bulk heterojunction perovskite solar cells based on room temperature deposited hole-blocking layer: Suppressed hysteresis and flexible photovoltaic application

NASA Astrophysics Data System (ADS)

Chen, Zhiliang; Yang, Guang; Zheng, Xiaolu; Lei, Hongwei; Chen, Cong; Ma, Junjie; Wang, Hao; Fang, Guojia

2017-05-01

Perovskite solar cells have developed rapidly in recent years as the third generation solar cells. In spite of the great improvement achieved, there still exist some issues such as undesired hysteresis and indispensable high temperature process. In this work, bulk heterojunction perovskite-phenyl-C61-butyric acid methyl ester solar cells have been prepared to diminish hysteresis using a facile two step spin-coating method. Furthermore, high quality tin oxide films are fabricated using pulse laser deposition technique at room temperature without any annealing procedure. The as fabricated tin oxide film is successfully applied in bulk heterojunction perovskite solar cells as a hole blocking layer. Bulk heterojunction devices based on room temperature tin oxide exhibit almost hysteresis-free characteristics with power conversion efficiency of 17.29% and 14.0% on rigid and flexible substrates, respectively.

Thermal transfer recording media

NASA Astrophysics Data System (ADS)

Takei, T.; Taniguchi, M.; Fukushima, H.; Yamaguchi, Y.; Shinozuka, M.; Seikohsha, K. K. Suwa

1988-08-01

The recording media consist of more than or one coloring layer and a layer containing a flame retardant to ensure noncombustibility and good thermal transfer. Thus, a PET film was coated on a side with a compound containing Vylon 290 (polyester resin), AFR-1021 (decabromodiphenyl oxide) 8 and Polysafe 60 (Sb oxide), and coated on the other side with a compound containing carnauba wax, HNP-9 (paraffin wax), EV-410 (ethylene-vinyl acetate copolymer), and Cu phthalocyanine to give a thermal transfer recording medium which showed good noncombustibility and antiblocking properties, and provided high quality images.

Application of Silicon Micromachining to Thermal Dissipation Issues in Wafer Scale Integrated Circuits

DTIC Science & Technology

1991-12-01

the cartesian coordinate system, ( hkl ) is the general mathematical representation for a crystal plane. The planar densities of a crystal and the...furnace’s temperature was pre-equilibrated to the pre- set oxidation temperature of 1075 °C. Oxygen was bubbled through DIW at 95 °C to promote the growth...to the pre-set oxidation temperature of 1075 °C. An oxygen flow was initiated at 1 liter per minute to realize a high quality, dry SiO 2 thin-film on

Review of the Primary National Ambient Air Quality Standard for Sulfur Oxides: Risk and Exposure Assessment Planning Document

EPA Science Inventory

The U.S. Environmental Protection Agency (EPA) is conducting a review of the air quality criteria and the primary (health-based) national ambient air quality standards (NAAQS) for sulfur oxides (SOx). The major phases of the process for reviewing NAAQS include the following: (1) ...

Review of the Primary National Ambient Air Quality Standard for Sulfur Oxides: Risk and Exposure Assessment

EPA Science Inventory

Sulfur oxides are one of the six major air pollutants for which EPA has issued air quality criteria and established national ambient air quality standards (NAAQS) based on those criteria. The Clear Air Act (CAA) requires EPA to periodically review and revise, as appropriate, exis...

Enhanced representation of soil NO emissions in the Community Multiscale Air Quality (CMAQ) model version 5.0.2

EPA Science Inventory

Modeling of soil nitric oxide (NO) emissions is highly uncertain and may misrepresent its spatial and temporal distribution. This study builds upon a recently introduced parameterization to improve the timing and spatial distribution of soil NO emission estimates in the Community...

Two year measurement of nitrous oxide emission from high frequency surface and subsurface drip irrigations in pomegranate orchard

USDA-ARS?s Scientific Manuscript database

Building resiliency in California agriculture means utilizing adaptive farming practices that will produce better yields while overcoming the State’s current challenges, such as diminishing water supply and deteriorating water quality. In addition, California agriculture also needs to take proactive...

Fabrication of free standing anodic titanium oxide membranes with clean surface using recycling process.

PubMed

Meng, Xianhui; Lee, Tae-Young; Chen, Huiyu; Shin, Dong-Wook; Kwon, Kee-Won; Kwon, Sang Jik; Yoo, Ji-Beom

2010-07-01

Large area of self-organized, free standing anodic titanium oxide (ATO) nanotube membranes with clean surfaces were facilely prepared to desired lengths via electrochemical anodization of highly pure Ti sheets in an ethylene glycol electrolyte, with a small amount of NH4F and H2O at 50 V, followed by self-detachment of the ATO membrane from the Ti substrate using recycling processes. In the first anodization step, the nanowire oxide layer existed over the well-arranged ATO nanotube. After sufficiently rinsing with water, the whole ATO layer was removed from the Ti sheet by high pressure N2 gas, and a well-patterned dimple layer with a thickness of about 30 nm existed on the Ti substrate. By using these naturally formed nano-scale pits as templates, in the second and third anodization process, highly ordered, vertically aligned, and free standing ATO membranes with the anodic aluminum oxide (AAO)-like clean surface were obtained. The inter-pore distance and diameter was 154 +/- 2 nm and 91+/- 2 nm, the tube arrays lengths for 25 and 46 hours were 44 and 70 microm, respectively. The present study demonstrates a simple approach to producing high quality, length controllable, large area TiO2 membrane.

Gases for establishing pneumoperitoneum during laparoscopic abdominal surgery.

PubMed

Yu, Tianwu; Cheng, Yao; Wang, Xiaomei; Tu, Bing; Cheng, Nansheng; Gong, Jianping; Bai, Lian

2017-06-21

This is an update of the review published in 2013.Laparoscopic surgery is now widely performed to treat various abdominal diseases. Currently, carbon dioxide is the most frequently used gas for insufflation of the abdominal cavity (pneumoperitoneum). Although carbon dioxide meets most of the requirements for pneumoperitoneum, the absorption of carbon dioxide may be associated with adverse events. People with high anaesthetic risk are more likely to experience cardiopulmonary complications and adverse events, for example hypercapnia and acidosis, which has to be avoided by hyperventilation. Therefore, other gases have been introduced as alternatives to carbon dioxide for establishing pneumoperitoneum. To assess the safety, benefits, and harms of different gases (i.e. carbon dioxide, helium, argon, nitrogen, nitrous oxide, and room air) used for establishing pneumoperitoneum in participants undergoing laparoscopic general abdominal or gynaecological pelvic surgery. We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (the Cochrane Library, 2016, Issue 9), Ovid MEDLINE (1950 to September 2016), Ovid Embase (1974 to September 2016), Science Citation Index Expanded (1970 to September 2016), Chinese Biomedical Literature Database (CBM) (1978 to September 2016), ClinicalTrials.gov (September 2016), and World Health Organization International Clinical Trials Registry Platform (September 2016). We included randomised controlled trials (RCTs) comparing different gases for establishing pneumoperitoneum in participants (irrespective of age, sex, or race) undergoing laparoscopic abdominal or gynaecological pelvic surgery under general anaesthesia. Two review authors identified the trials for inclusion, collected the data, and assessed the risk of bias independently. We performed the meta-analyses using Review Manager 5. We calculated risk ratio (RR) for dichotomous outcomes (or Peto odds ratio for very rare outcomes), and mean difference (MD) or standardised mean difference (SMD) for continuous outcomes with 95% confidence intervals (CI). We used GRADE to rate the quality of evidence, MAIN RESULTS: We included nine RCTs, randomising 519 participants, comparing different gases for establishing pneumoperitoneum: nitrous oxide (three trials), helium (five trials), or room air (one trial) was compared to carbon dioxide. Three trials randomised participants to nitrous oxide pneumoperitoneum (100 participants) or carbon dioxide pneumoperitoneum (96 participants). None of the trials was at low risk of bias. There was insufficient evidence to determine the effects of nitrous oxide and carbon dioxide on cardiopulmonary complications (RR 2.00, 95% CI 0.38 to 10.43; two studies; 140 participants; very low quality of evidence), or surgical morbidity (RR 1.01, 95% CI 0.18 to 5.71; two studies; 143 participants; very low quality of evidence). There were no serious adverse events related to either nitrous oxide or carbon dioxide pneumoperitoneum (three studies; 196 participants; very low quality of evidence). We could not combine data from two trials (140 participants) which individually showed lower pain scores (a difference of about one visual analogue score on a scale of 1 to 10 with lower numbers indicating less pain) with nitrous oxide pneumoperitoneum at various time points on the first postoperative day, and this was rated asvery low quality .Four trials randomised participants to helium pneumoperitoneum (69 participants) or carbon dioxide pneumoperitoneum (75 participants) and one trial involving 33 participants did not state the number of participants in each group. None of the trials was at low risk of bias. There was insufficient evidence to determine the effects of helium or carbon dioxide on cardiopulmonary complications (RR 1.46, 95% CI 0.35 to 6.12; three studies; 128 participants; very low quality of evidence) or pain scores (visual analogue score on a scale of 1 to 10 with lower numbers indicating less pain; MD 0.49 cm, 95% CI -0.28 to 1.26; two studies; 108 participants; very low quality of evidence). There were three serious adverse events (subcutaneous emphysema) related to helium pneumoperitoneum (three studies; 128 participants; very low quality of evidence).One trial randomised participants to room air pneumoperitoneum (70 participants) or carbon dioxide pneumoperitoneum (76 participants). The trial was at unclear risk of bias. There were no cardiopulmonary complications or serious adverse events observed related to either room air or carbon dioxide pneumoperitoneum (both outcomes very low quality of evidence). The evidence of lower hospital costs and reduced pain during the first postoperative day with room air pneumoperitoneum compared with carbon dioxide pneumoperitoneum (a difference of about one visual analogue score on a scale of 1 to 10 with lower numbers indicating less pain, was rated as very low quality of evidence. The quality of the current evidence is very low. The effects of nitrous oxide and helium pneumoperitoneum compared with carbon dioxide pneumoperitoneum are uncertain. Evidence from one trial of small sample size suggests that room air pneumoperitoneum may decrease hospital costs in people undergoing laparoscopic abdominal surgery. The safety of nitrous oxide, helium, and room air pneumoperitoneum has yet to be established.Further trials on this topic are needed, and should compare various gases (i.e. nitrous oxide, helium, argon, nitrogen, and room air) with carbon dioxide under standard pressure pneumoperitoneum with cold gas insufflation for people with high anaesthetic risk. Future trials should include outcomes such as complications, serious adverse events, quality of life, and pain.

Scenedesmus incrassatulus CLHE-Si01: a potential source of renewable lipid for high quality biodiesel production.

PubMed

Arias-Peñaranda, Martha T; Cristiani-Urbina, Eliseo; Montes-Horcasitas, Carmen; Esparza-García, Fernando; Torzillo, Giuseppe; Cañizares-Villanueva, Rosa Olivia

2013-07-01

The potential of microalgal oil from Scenedesmus incrassatulus as a feedstock for biodiesel production was studied. Cell concentration of S. incrassatulus and lipid content obtained during mixotrophic growth were 1.8 g/L and 19.5 ± 1.5% dry cell weight, respectively. The major components of biodiesel obtained from S. incrassatulus oil were methyl palmitate (26%) and methyl linoleate (49%), which provided a strong indication of high quality biodiesel. Fuel properties were determined by empirical equations and found to be within the limits of biodiesel standard ASTM D6751 and EN 14214. The quality properties of the biodiesel were high cetane number (62), low density (803 kg/m(3)), low viscosity (3.78 mm(2)/s), oxidation stability (9h) and cold filter plugging point (-4°C). Hence, S. incrassatulus has potential as a feedstock for the production of excellent quality biodiesel. Copyright © 2013 Elsevier Ltd. All rights reserved.

Enhance the pyroelectricity of polyvinylidene fluoride by graphene-oxide doping.

PubMed

Hu, Yuh-Chung; Hsu, Wei-Li; Wang, Yi-Ta; Ho, Cheng-Tao; Chang, Pei-Zen

2014-04-16

The high quality properties and benefits of graphene-oxide have generated an active area of research where many investigations have shown potential applications in various technological fields. This paper proposes a methodology for enhancing the pyro-electricity of PVDF by graphene-oxide doping. The PVDF film with graphene-oxide is prepared by the sol-gel method. Firstly, PVDF and graphene-oxide powders are dispersed into dimethylformamide as solvent to form a sol solution. Secondly, the sol solution is deposited on a flexible ITO/PET substrate by spin-coating. Thirdly, the particles in the sol solution are polymerized through baking off the solvent to produce a gel in a state of a continuous network of PVDF and graphene-oxide. The final annealing process pyrolyzes the gel and form a β-phase PVDF film with graphene-oxide doping. A complete study on the process of the graphene oxide doping of PVDF is accomplished. Some key points about the process are addressed based on experiments. The solutions to some key issues are found in this work, such as the porosity of film, the annealing temperature limitation by the use of flexible PET substrate, and the concentrations of PVDF and graphene-oxide.

Abrupt recent trend changes in atmospheric nitrogen dioxide over the Middle East

PubMed Central

Lelieveld, Jos; Beirle, Steffen; Hörmann, Christoph; Stenchikov, Georgiy; Wagner, Thomas

2015-01-01

Nitrogen oxides, released from fossil fuel use and other combustion processes, affect air quality and climate. From the mid-1990s onward, nitrogen dioxide (NO2) has been monitored from space, and since 2004 with relatively high spatial resolution by the Ozone Monitoring Instrument. Strong upward NO2 trends have been observed over South and East Asia and the Middle East, in particular over major cities. We show, however, that a combination of air quality control and political factors, including economical crisis and armed conflict, has drastically altered the emission landscape of nitrogen oxides in the Middle East. Large changes, including trend reversals, have occurred since about 2010 that could not have been predicted and therefore are at odds with emission scenarios used in projections of air pollution and climate change in the early 21st century. PMID:26601240

Oxidation-assisted graphene heteroepitaxy on copper foil.

PubMed

Reckinger, Nicolas; Tang, Xiaohui; Joucken, Frédéric; Lajaunie, Luc; Arenal, Raul; Dubois, Emmanuel; Hackens, Benoît; Henrard, Luc; Colomer, Jean-François

2016-11-10

We propose an innovative, easy-to-implement approach to synthesize aligned large-area single-crystalline graphene flakes by chemical vapor deposition on copper foil. This method doubly takes advantage of residual oxygen present in the gas phase. First, by slightly oxidizing the copper surface, we induce grain boundary pinning in copper and, in consequence, the freezing of the thermal recrystallization process. Subsequent reduction of copper under hydrogen suddenly unlocks the delayed reconstruction, favoring the growth of centimeter-sized copper (111) grains through the mechanism of abnormal grain growth. Second, the oxidation of the copper surface also drastically reduces the nucleation density of graphene. This oxidation/reduction sequence leads to the synthesis of aligned millimeter-sized monolayer graphene domains in epitaxial registry with copper (111). The as-grown graphene flakes are demonstrated to be both single-crystalline and of high quality.

Influence of the nanotube oxidation on the rheological and electrical properties of CNT/HDPE composites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nobile, Maria Rossella, E-mail: mrnobile@unisa.it; Somma, Elvira; Valentino, Olga

Rheological and electrical properties of nanocomposites based on multi-walled carbon nanotubes (MWNTs) and high density polyethylene (HDPE), prepared by melt mixing in a micro-twin screw extruder, have been investigated. The effect of MWNT concentration (0.5 and 2.5 wt %) and nanotube surface treatment (oxidative treatment in a tubular furnace at 500°C for 1 hr in a 95% nitrogen, 5% oxygen atmosphere) has been analyzed. It has been found that the sample conductivity with oxidation of the nanotubes decreases more than 2 orders of magnitude. Scanning electron microscopy showed good adhesion and dispersion of nanotubes in the matrix, independently of themore » surface treatment. Electrical and rheological measurements revealed that the oxidative treatment, causing some reduction of the MWNT quality, decreases the efficiency of the nanotube matrix interaction.« less

Efficacy of l-carnitine administration on fatigue, nutritional status, oxidative stress, and related quality of life in 12 advanced cancer patients undergoing anticancer therapy.

PubMed

Gramignano, Giulia; Lusso, Maria Rita; Madeddu, Clelia; Massa, Elena; Serpe, Roberto; Deiana, Laura; Lamonica, Giovanna; Dessì, Mariele; Spiga, Carla; Astara, Giorgio; Macciò, Antonio; Mantovani, Giovanni

2006-02-01

Fatigue is a multidimensional symptom that is described in terms of perceived energy, mental capacity, and psychological status: it can impair daily functioning and lead to negative effects on quality of life. It is one of the most common side effects of chemotherapy and radiotherapy. In recent studies, l-carnitine (LC) supplementation has been demonstrated to be able to improve fatigue symptoms in patients with cancer. In the present study we tested the efficacy and safety of LC supplementation in a population of patients who had advanced cancer and developed fatigue, high blood levels of reactive oxygen species, or both. As outcome measures we evaluated fatigue and quality of life in relation to oxidative stress, nutritional status, and laboratory variables, mainly levels of reactive oxygen species, glutathione peroxidase, and proinflammatory cytokines. From March to July 2004, 12 patients who had advanced tumors (50% at stage IV) at different sites were enrolled (male-to-female ratio 2:10, mean age 60 y, range 42-73). Patients were only slightly anemic (hemoglobin 10.9 g/dL) and hemoglobin levels did not change after treatment. LC was administered orally at 6 g/d for 4 wk. All patients underwent antineoplastic treatment during LC supplementation. Fatigue, as measured by the Multidimensional Fatigue Symptom Inventory-Short Form, decreased significantly, particularly for the General and Physical scales, and for quality of life in each subscale of quality of life in relation to oxidative stress. Nutritional variables (lean body mass and appetite) increased significantly after LC supplementation. Levels of reactive oxygen species decreased and glutathione peroxidase increased but not significantly. Proinflammatory cytokines did not change significantly. Improvement of symptoms with respect to fatigue and quality of life in relation to oxidative stress may be explained mainly by an increase in lean body mass, which may be considered the most important nutritional or functional parameter in assessing the cachectic state of patients. In this view, fatigue with related symptoms can well be considered an important constituent of cancer-related anorexia cachexia syndrome.

Au Nanoparticle Sub-Monolayers Sandwiched between Sol-Gel Oxide Thin Films

PubMed Central

Della Gaspera, Enrico; Menin, Enrico; Sada, Cinzia

2018-01-01

Sub-monolayers of monodisperse Au colloids with different surface coverage have been embedded in between two different metal oxide thin films, combining sol-gel depositions and proper substrates functionalization processes. The synthetized films were TiO2, ZnO, and NiO. X-ray diffraction shows the crystallinity of all the oxides and verifies the nominal surface coverage of Au colloids. The surface plasmon resonance (SPR) of the metal nanoparticles is affected by both bottom and top oxides: in fact, the SPR peak of Au that is sandwiched between two different oxides is centered between the SPR frequencies of Au sub-monolayers covered with only one oxide, suggesting that Au colloids effectively lay in between the two oxide layers. The desired organization of Au nanoparticles and the morphological structure of the prepared multi-layered structures has been confirmed by Rutherford backscattering spectrometry (RBS), Secondary Ion Mass Spectrometry (SIMS), and Scanning Electron Microscopy (SEM) analyses that show a high quality sandwich structure. The multi-layered structures have been also tested as optical gas sensors. PMID:29538338

Investigation of stability, consistency, and oil oxidation of emulsion filled gel prepared by inulin and rice bran oil using ultrasonic radiation.

PubMed

Nourbehesht, Newsha; Shekarchizadeh, Hajar; Soltanizadeh, Nafiseh

2018-04-01

Inulin, rice bran oil and rosemary essential oil were used to produce high quality emulsion filled gel (EFG) using ultrasonic radiation. Response surface methodology was used to investigate the effects of oil content, inulin content and power of ultrasound on the stability and consistency of prepared EFG. The process conditions were optimized by conducting experiments at five different levels. Second order polynomial response surface equations were developed indicating the effect of variables on EFG stability and consistency. The oil content of 18%; inulin content of 44.6%; and power of ultrasound of 256 W were found to be the optimum conditions to achieve the best EFG stability and consistency. Microstructure and rheological properties of prepared EFG were investigated. Oil oxidation as a result of using ultrasonic radiation was also investigated. The increase of oxidation products and the decrease of total phenolic compounds as well as radical scavenging activity of antioxidant compounds showed the damaging effect of ultrasound on the oil quality of EFG. Copyright © 2017 Elsevier B.V. All rights reserved.

Effect of packaging atmospheres on storage quality characteristics of heavily marbled beef longissimus steaks.

PubMed

Yang, Xiaoyin; Zhang, Yimin; Zhu, Lixian; Han, Mingshan; Gao, Shujuan; Luo, Xin

2016-07-01

The objective of this study was to investigate the effects of modified atmosphere packaging (MAP) systems on shelf-life and quality of beef steaks with high marbling. Four packaging types were used including 80% O2 MAP (80% O2+20% CO2), 50% O2 MAP (50% O2+30% CO2+20% N2), carbon monoxide MAP (0.4% CO+30% CO2+69.6% N2) and vacuum packaging (VP). Steaks were displayed under simulated retail conditions at 4°C for 12days. Purge loss, pH, color stability, oxidative stability and microbial counts were monitored. Aerobically packaged steaks exhibited a bright-red color at the first 4days. However, discoloration and oxidation became major factors limiting their shelf-life to 8days. Compared with aerobic packaging, anaerobic packaging extended shelf-life of heavily marbled beef steaks, due to better color stability, together with lower oxidation and microbial populations. Among all packaging methods, CO-MAP had the best preservation for steaks, with more red color than other packaging types. Copyright © 2016 Elsevier Ltd. All rights reserved.

Multi-dimensional water quality assessment of an urban drinking water source elucidated by high resolution underwater towed vehicle mapping.

PubMed

Lock, Alan; Spiers, Graeme; Hostetler, Blair; Ray, James; Wallschläger, Dirk

2016-04-15

Spatial surveys of Ramsey Lake, Sudbury, Ontario water quality were conducted using an innovative underwater towed vehicle (UTV) equipped with a multi-parameter probe providing real-time water quality data. The UTV revealed underwater vent sites through high resolution monitoring of different spatial chemical characteristics using common sensors (turbidity, chloride, dissolved oxygen, and oxidation/reduction sensors) that would not be feasible with traditional water sampling methods. Multi-parameter probe vent site identification is supported by elevated alkalinity and silica concentrations at these sites. The identified groundwater vent sites appear to be controlled by bedrock fractures that transport water from different sources with different contaminants of concern. Elevated contaminants, such as, arsenic and nickel and/or nutrient concentrations are evident at the vent sites, illustrating the potential of these sources to degrade water quality. Copyright © 2016 Elsevier Ltd. All rights reserved.

Methods for producing monodispersed particles of barium titanate

DOEpatents

Hu, Zhong-Cheng

2001-01-01

The present invention is a low-temperature controlled method for producing high-quality, ultrafine monodispersed nanocrystalline microsphere powders of barium titanate and other pure or composite oxide materials having particles ranging from nanosized to micronsized particles. The method of the subject invention comprises a two-stage process. The first stage produces high quality monodispersed hydrous titania microsphere particles prepared by homogeneous precipitation via dielectric tuning in alcohol-water mixed solutions of inorganic salts. Titanium tetrachloride is used as an inorganic salt precursor material. The second stage converts the pure hydrous titania microsphere particles into crystalline barium titanate microsphere powders via low-temperature, hydrothermal reactions.

Urea-assisted liquid-phase exfoliation of natural graphite into few-layer graphene

NASA Astrophysics Data System (ADS)

Hou, Dandan; Liu, Qinfu; Wang, Xianshuai; Qiao, Zhichuan; Wu, Yingke; Xu, Bohui; Ding, Shuli

2018-05-01

The mass production of graphene with high quality is desirable for its wide applications. Here, we demonstrated a facile method to exfoliate natural graphite into graphene in organic solvent by assisting of urea. The exfoliation of graphite may originate from the "molecular wedge" effect of urea, which can intercalate into the edge of natural graphite, thus facilitating the production of graphene dispersion with a high concentration up to 1.2 mg/mL. The obtained graphene is non-oxidized with negligible defects. Therefore, this approach has great promise in bulk production of graphene with superior quality for a variety of applications.

A Review on Advanced Treatment of Pharmaceutical Wastewater

NASA Astrophysics Data System (ADS)

Guo, Y.; Qi, P. S.; Liu, Y. Z.

2017-05-01

The composition of pharmaceutical wastewater is complex, which is high concentration of organic matter, microbial toxicity, high salt, and difficult to biodegrade. After secondary treatment, there are still trace amounts of suspended solids and dissolved organic matter. To improve the quality of pharmaceutical wastewater effluent, advanced treatment is essential. In this paper, the classification of the pharmaceutical technology was introduced, and the characteristics of pharmaceutical wastewater effluent quality were summarized. The methods of advanced treatment of pharmaceutical wastewater were reviewed afterwards, which included coagulation and sedimentation, flotation, activated carbon adsorption, membrane separation, advanced oxidation processes, membrane separation and biological treatment. Meanwhile, the characteristics of each process were described.

76 FR 59599 - Extension of Comment Period for Secondary National Ambient Air Quality Standards for Oxides of...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-09-27

... Sulfur AGENCY: Environmental Protection Agency (EPA). ACTION: Notice of extension of public comment... National Ambient Air Quality Standards for Oxides of Nitrogen and Sulfur to October 10, 2011. DATES: The... Nitrogen and Sulfur'' proposed rule should be addressed to Rich Scheffe, U.S. EPA, Office of Air Quality...

Policy Assessment for the Review of the Primary National Ambient Air Quality Standard for Sulfur Oxides, External Review Draft

EPA Science Inventory

Sulfur oxides are one of the six major air pollutants for which EPA has issued air quality criteria and established national ambient air quality standards (NAAQS) based on those criteria. The Clear Air Act (CAA) requires EPA to periodically review and revise, as appropriate, exis...

Variation Quality and Kinetic Parameter of Commercial n-3 PUFA-Rich Oil during Oxidation via Rancimat

PubMed Central

Yang, Kai-Min; Chiang, Po-Yuan

2017-01-01

Different biological sources of n-3 polyunsaturated fatty acids (n-3 PUFA) in mainstream commercial products include algae and fish. Lipid oxidation in n-3 PUFA-rich oil is the most important cause of its deterioration. We investigated the kinetic parameters of n-3 PUFA-rich oil during oxidation via Rancimat (at a temperature range of 70~100 °C). This was done on the basis of the Arrhenius equation, which indicates that the activation energies (Ea) for oxidative stability are 82.84–96.98 KJ/mol. The chemical substrates of different oxidative levels resulting from oxidation via Rancimat at 80 °C were evaluated. At the initiation of oxidation, the tocopherols in the oil degraded very quickly, resulting in diminished protection against further oxidation. Then, the degradation of the fatty acids with n-3 PUFA-rich oil was evident because of decreased levels of PUFA along with increased levels of saturated fatty acids (SFA). The quality deterioration from n-3 PUFA-rich oil at the various oxidative levels was analyzed chemometrically. The anisidine value (p-AV, r: 0.92) and total oxidation value (TOTOX, r: 0.91) exhibited a good linear relationship in a principal component analysis (PCA), while oxidative change and a significant quality change to the induction period (IP) were detected through an agglomerative hierarchical cluster (AHC) analysis. PMID:28350348

Variation Quality and Kinetic Parameter of Commercial n-3 PUFA-Rich Oil during Oxidation via Rancimat.

PubMed

Yang, Kai-Min; Chiang, Po-Yuan

2017-03-28

Different biological sources of n -3 polyunsaturated fatty acids ( n -3 PUFA) in mainstream commercial products include algae and fish. Lipid oxidation in n -3 PUFA-rich oil is the most important cause of its deterioration. We investigated the kinetic parameters of n -3 PUFA-rich oil during oxidation via Rancimat (at a temperature range of 70~100 °C). This was done on the basis of the Arrhenius equation, which indicates that the activation energies ( E a) for oxidative stability are 82.84-96.98 KJ/mol. The chemical substrates of different oxidative levels resulting from oxidation via Rancimat at 80 °C were evaluated. At the initiation of oxidation, the tocopherols in the oil degraded very quickly, resulting in diminished protection against further oxidation. Then, the degradation of the fatty acids with n -3 PUFA-rich oil was evident because of decreased levels of PUFA along with increased levels of saturated fatty acids (SFA). The quality deterioration from n -3 PUFA-rich oil at the various oxidative levels was analyzed chemometrically. The anisidine value (p-AV, r: 0.92) and total oxidation value (TOTOX, r: 0.91) exhibited a good linear relationship in a principal component analysis (PCA), while oxidative change and a significant quality change to the induction period (IP) were detected through an agglomerative hierarchical cluster (AHC) analysis.

Nitrous oxide-based techniques versus nitrous oxide-free techniques for general anaesthesia.

PubMed

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 anaesthesia (or both) with any general anaesthesia using a volatile anaesthetic or propofol-based maintenance of anaesthesia but no nitrous oxide for adults undergoing surgery. Our primary outcome was inhospital case fatality rate. Secondary outcomes were complications and length of stay. Two review authors independently assessed trial quality and extracted the outcome data. We used meta-analysis for data synthesis. Heterogeneity was examined with the Chi² test and by calculating the I² statistic. We used a fixed-effect model if the measure of inconsistency was low for all comparisons (I² statistic < 50%); otherwise we used a random-effects model for measures with high inconsistency. We undertook subgroup analyses to explore inconsistency and sensitivity analyses to evaluate whether the results were robust. We assessed the quality of evidence of the main outcomes using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system. We included 35 trials (13,872 adult participants). Seven included studies were at low risk of bias. We identified eight studies as awaiting classification since we could not obtain the full texts, and had insufficient information to include or exclude them. We included data from 24 trials for quantitative synthesis. The results of meta-analyses showed that nitrous oxide-based techniques increased the incidence of pulmonary atelectasis (odds ratio (OR) 1.57, 95% confidence interval (CI) 1.18 to 2.10, P = 0.002), but had no effects on the inhospital case fatality rate, the incidence of pneumonia, myocardial infarction, stroke, severe nausea and vomiting, venous thromboembolism, wound infection, or the length of hospital stay. The sensitivity analyses suggested that the results of the meta-analyses were all robust except for the outcomes of pneumonia, and severe nausea and vomiting. Two trials reported length of intensive care unit (ICU) stay but the data were skewed so were not pooled. Both trials reported that nitrous oxide-based techniques had no effects on the length of ICU stay. We rated the quality of evidence for two outcomes (pulmonary atelectasis, myocardial infarction) as high, four outcomes (inhospital case fatality rate, stroke, venous thromboembolism, length of hospital stay) as moderate, and three (pneumonia, severe nausea and vomiting, wound infection rate) as low. Given the evidence from this Cochrane review, the avoidance of nitrous oxide may be reasonable in participants with pre-existing poor pulmonary function or at high risk of postoperative nausea and vomiting. Since there are eight studies awaiting classification, selection bias may exist in our systematic review.

Facile fabrication of high-quality Ag/PS coaxial nanocables based on the mixed mode of soft/hard templates

NASA Astrophysics Data System (ADS)

Wan, Mimi; Zhao, Wenbo; Peng, Fang; Wang, Qi; Xu, Ping; Mao, Chun; Shen, Jian

2016-08-01

A new kind of high-quality Ag/PS coaxial nanocables can be facilely synthesized by using soft/hard templates method. In order to effectively introduce Ag sources into porous polystyrene (PS) nanotubes which were trapped in porous anodic aluminum oxide (AAO) hard template, Pluronic F127 (F127) was used as guiding agent, soft template and reductant. Meanwhile, ethylene glycol solution was also used as solvent and co-reducing agent to assist in the formation of silver nanowires. The influences of concentration of F127 and reducing reaction time on the formation of Ag/PS coaxial nanocables were discussed. Results indicated that the high-quality Ag/PS coaxial nanocables can be obtained by the mixed mode of soft/hard templates under optimized conditions. This strategy is expected to be extended to design more metal/polymer coaxial nanocables for the benefit of creation of complex and functional nanoarchitectures and components.

Magneto-Optical Thin Films for On-Chip Monolithic Integration of Non-Reciprocal Photonic Devices

PubMed Central

Bi, Lei; Hu, Juejun; Jiang, Peng; Kim, Hyun Suk; Kim, Dong Hun; Onbasli, Mehmet Cengiz; Dionne, Gerald F.; Ross, Caroline A.

2013-01-01

Achieving monolithic integration of nonreciprocal photonic devices on semiconductor substrates has been long sought by the photonics research society. One way to achieve this goal is to deposit high quality magneto-optical oxide thin films on a semiconductor substrate. In this paper, we review our recent research activity on magneto-optical oxide thin films toward the goal of monolithic integration of nonreciprocal photonic devices on silicon. We demonstrate high Faraday rotation at telecommunication wavelengths in several novel magnetooptical oxide thin films including Co substituted CeO2−δ, Co- or Fe-substituted SrTiO3−δ, as well as polycrystalline garnets on silicon. Figures of merit of 3~4 deg/dB and 21 deg/dB are achieved in epitaxial Sr(Ti0.2Ga0.4Fe0.4)O3−δ and polycrystalline (CeY2)Fe5O12 films, respectively. We also demonstrate an optical isolator on silicon, based on a racetrack resonator using polycrystalline (CeY2)Fe5O12/silicon strip-loaded waveguides. Our work demonstrates that physical vapor deposited magneto-optical oxide thin films on silicon can achieve high Faraday rotation, low optical loss and high magneto-optical figure of merit, therefore enabling novel high-performance non-reciprocal photonic devices monolithically integrated on semiconductor substrates. PMID:28788379

Optimized ultra-thin manganin alloy passivated fine-pitch damascene compatible bump-less Cu-Cu bonding at sub 200 °C for three-dimensional Integration applications

NASA Astrophysics Data System (ADS)

Panigrahi, Asisa Kumar; Hemanth Kumar, C.; Bonam, Satish; Ghosh, Tamal; Rama Krishna Vanjari, Siva; Govind Singh, Shiv

2018-02-01

Enhanced Cu diffusion, Cu surface passivation, and smooth surface at the bonding interface are the key essentials for high quality Cu-Cu bonding. Previously, we have demonstrated optimized 3 nm thin Manganin metal-alloy passivation from oxidation and also helps to reduce the surface roughness to about 0.8 nm which substantially led to high quality Cu-Cu bonding. In this paper, we demonstrated an ultra fine-pitch (<25 µm) Cu-Cu bonding using an optimized Manganin metal-alloy passivation. This engineered surface passivation approach led to high quality bonding at sub 200 °C temperature and 0.4 MPa. Very low specific contact resistance of 1.4 × 10-7 Ω cm2 and the defect free bonded interface is clear indication of high quality bonding for future multilayer integrations. Furthermore, electrical characterization of the bonded structure was performed under various robust conditions as per International Technology Roadmap for Semiconductors (ITRS Roadmap) in order to satisfy the stability of the bonded structure.

Ultrathin Nickel Hydroxide and Oxide Nanosheets: Synthesis, Characterizations and Excellent Supercapacitor Performances

PubMed Central

Zhu, Youqi; Cao, Chuanbao; Tao, Shi; Chu, Wangsheng; Wu, Ziyu; Li, Yadong

2014-01-01

High-quality ultrathin two-dimensional nanosheets of α-Ni(OH)2 are synthesized at large scale via microwave-assisted liquid-phase growth under low-temperature atmospheric conditions. After heat treatment, non-layered NiO nanosheets are obtained while maintaining their original frame structure. The well-defined and freestanding nanosheets exhibit a micron-sized planar area and ultrathin thickness (<2 nm), suggesting an ultrahigh surface atom ratio with unique surface and electronic structure. The ultrathin 2D nanostructure can make most atoms exposed outside with high activity thus facilitate the surface-dependent electrochemical reaction processes. The ultrathin α-Ni(OH)2 and NiO nanosheets exhibit enhanced supercapacitor performances. Particularly, the α-Ni(OH)2 nanosheets exhibit a maximum specific capacitance of 4172.5 F g−1 at a current density of 1 A g−1. Even at higher rate of 16 A g−1, the specific capacitance is still maintained at 2680 F g−1 with 98.5% retention after 2000 cycles. Even more important, we develop a facile and scalable method to produce high-quality ultrathin transition metal hydroxide and oxide nanosheets and make a possibility in commercial applications. PMID:25168127

Effect of muscle type and frozen storage on the quality parameters of Iberian restructured meat preparations.

PubMed

Antequera, Teresa; Pérez-Palacios, Trinidad; Rodas, Elena; Rodríguez, Mar; Córdoba, Juan J

2014-10-01

The main objective of this study was to evaluate the effect of muscle type and frozen storage on the quality of restructured meat preparations from undervalued Iberian muscle to make use of meat from a high-quality and natural pig production system. The effect of two muscle types (i.e. white-glycolytic (W) and red-oxidative (R)) and frozen storage (lasting 0, 30, 60 and 90 days) on quality characteristics were assessed. Significant differences were found between the W and R Iberian restructured preparations in most physicochemical and some colour, texture and sensory traits, and in the fatty acid profile and oxidative measurements, suggesting that the R muscles are more suitable; however, the microbial contamination should be reduced. Frozen storage reduced but did not eliminate the initial microbial contamination, and it enhanced some quality traits in the Iberian restructured preparations, i.e. increased a* values, cohesiveness and juiciness and decreased adhesiveness and pastiness, without negatively affecting any parameter. Thus, frozen Iberian restructured preparations are recommended to be commercialized. In addition, the implementation or revision of Hazard Analysis and Critical Control Point is recommended to reduce microbial contamination. © The Author(s) 2013 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Effect of Vitamin E and Polyunsaturated Fatty Acids on Cryopreserved Sperm Quality in Bos taurus Bulls Under Testicular Heat Stress.

PubMed

Losano, João D A; Angrimani, Daniel S R; Dalmazzo, Andressa; Rocha, Carolina C; Brito, Maíra M; Perez, Eduardo G A; Tsunoda, Roberta H; Góes, Paola A A; Mendes, Camilla M; Assumpção, Mayra E O A; Barnabe, Valquiria H; Nichi, Marcilio

2018-04-03

Taurine bulls are highly susceptible to heat stress, leading to increased oxidative stress (OS) and impaired sperm viability. Polyunsaturated fatty acids (PUFAs) supplementation can be an alternative to improve semen quality, which also results in more sperm susceptibility to lipid peroxidation. Moreover, this deleterious effect can be exacerbated in animals affected by heat stress. Vitamin E is a key antioxidant that counteracts lipid peroxidation of sperm membrane caused by OS. Thus, combining PUFAs with vitamin E may improve sperm quality. In this context, this study aimed to evaluate the effect of interaction between PUFAs and vitamin E on sperm quality in Bos taurus bulls under testicular heat stress. Sixteen taurine bulls under testicular heat stress were randomly assigned in four groups: Control, Vitamin E, PUFA, and PUFA + Vitamin E. All groups lasted for 60 days. Samples were cryopreserved/thawed and analyzed for motility variables (CASA), membrane and acrosome integrity, mitochondrial activity, susceptibility to oxidative stress, DNA integrity, and sperm-binding capacity. Results showed that vitamin E had a beneficial effect on some sperm characteristics, whereas PUFA supplementation had an adverse effect when the two treatments were evaluated separately. Finally, the association between PUFAs and vitamin E did not improve sperm quality.

Soluble Graphene Nanosheets from Recycled Graphite of Spent Lithium Ion Batteries

NASA Astrophysics Data System (ADS)

Zhao, Liangliang; Liu, Xiya; Wan, Chuanyun; Ye, Xiangrong; Wu, Fanhong

2018-02-01

Soluble graphene nanosheets are fabricated from recycled graphite of spent lithium ion batteries through a modified Hammers process followed by deoxygenation with NaOH-KOH eutectic. Ultrasonic exfoliation in N-methyl-pyrrolidone indicates the loosened graphene layers in recycled graphite are prone to exfoliation. Reduction of the exfoliated graphene oxide sheets was conducted in molten NaOH-KOH eutectic at different temperatures. The results show that molten NaOH-KOH effectively eliminates the unsaturated oxygen-containing moieties from the exfoliated graphene oxide sheets while creating more hydroxyl functional groups. Higher temperature treatment is more prone to remove hydroxyls while producing the shrinkage on the surface of graphene sheets. Graphene sheet with a good solubility is produced when the graphene oxide is heat-treated at 220 °C for 10 h. After reduction, the graphene oxide sheets exhibit excellent dispersibility or solubility in water, ethanol and other polar solvents, therefore being highly desirable for solution processing of graphene materials. Such study not only identifies a high-quality stockpile to prepare soluble graphene but also paves a feasible alternative of graphite recycling from spent lithium batteries.

Energy conditions of high quality laser-oxygen cutting of mild steel

NASA Astrophysics Data System (ADS)

Shulyatyev, V. B.; Orishich, A. M.; Malikov, A. G.

2011-02-01

In our previous work we found experimentally the scaling laws for the oxygen-assisted laser cutting of low-carbon steel of 5 - 25 mm. No dross and minimal roughness of the cut surface were chosen as criteria of quality. Formulas were obtained to determine the optimum values of the laser power and cutting speed for the given sheet thickness. In the present paper, the energy balance of the oxygen-assisted laser cutting is studied experimentally at these optimum parameters. The absorbed laser energy and heat conduction losses and cut width were measured experimentally, and then the energy of exothermic reaction of oxidation was found from the balance equation. To define the integral coefficient of absorption, the laser power was measured on the cutting channel exit during the cutting. The heat conduction losses were measured by the calorimetric method. It has been established that the absorbed laser energy, oxidation energy, thermal losses and melting enthalpy related to a sheet thickness unit, do not depend on the sheet thickness at the cutting with the minimal roughness. The results enable to determine the fraction of the oxidized iron in the melt and thermal efficiency at the cutting with the minimal roughness. The share of the oxidation reaction energy is 50 - 60% in the total contributed energy.

Evidence for participation of the methionine sulfoxide reductase repair system in plant seed longevity

PubMed Central

Châtelain, Emilie; Satour, Pascale; Laugier, Edith; Ly Vu, Benoit; Payet, Nicole; Rey, Pascal; Montrichard, Françoise

2013-01-01

Seeds are in a natural oxidative context leading to protein oxidation. Although inevitable for proper progression from maturation to germination, protein oxidation at high levels is detrimental and associated with seed aging. Oxidation of methionine to methionine sulfoxide is a common form of damage observed during aging in all organisms. This damage is reversible through the action of methionine sulfoxide reductases (MSRs), which play key roles in lifespan control in yeast and animal cells. To investigate the relationship between MSR capacity and longevity in plant seeds, we first used two Medicago truncatula genotypes with contrasting seed quality. After characterizing the MSR family in this species, we analyzed gene expression and enzymatic activity in immature and mature seeds exhibiting distinct quality levels. We found a very strong correlation between the initial MSR capacities in different lots of mature seeds of the two genotypes and the time to a drop in viability to 50% after controlled deterioration. We then analyzed seed longevity in Arabidopsis thaliana lines, in which MSR gene expression has been genetically altered, and observed a positive correlation between MSR capacity and longevity in these seeds as well. Based on our data, we propose that the MSR repair system plays a decisive role in the establishment and preservation of longevity in plant seeds. PMID:23401556

Chemical vapor deposition of high T(sub c) superconducting films in a microgravity environment

NASA Technical Reports Server (NTRS)

Levy, Moises; Sarma, Bimal K.

1994-01-01

Since the discovery of the YBaCuO bulk materials in 1987, Metalorganic Chemical Vapor Deposition (MOCVD) has been proposed for preparing HTSC high T(sub c) films. This technique is now capable of producing high-T(sub c) superconducting thin films comparable in quality to those prepared by any other methods. The MOCVD technique has demonstrated its superior advantage in making large area high quality HTSC thin films and will play a major role in the advance of device applications of HTSC thin films. The organometallic precursors used in the MOCVD preparation of HTSC oxide thin films are most frequently metal beta-diketonates. High T(sub c) superconductors are multi-component oxides which require more than one component source, with each source, containing one kind of precursor. Because the volatility and stability of the precursors are strongly dependent on temperature, system pressure, and carrier gas flow rate, it has been difficult to control the gas phase composition, and hence film stoichiometry. In order circumvent these problems we have built and tested a single source MOCVD reactor in which a specially designed vaporizer was employed. This vaporizer can be used to volatilize a stoichiometric mixture of diketonates of yttrium, barium and copper to produce a mixed vapor in a 1:2:3 ratio respectively of the organometellics. This is accomplished even though the three compounds have significantly different volatilities. We have developed a model which provides insight into the process of vaporizing mixed precursors to produce high quality thin films of Y1Ba2Cu3O7. It shows that under steady state conditions the mixed organometallic vapor must have a stoichiometric ratio of the individual organometallics identical to that in the solid mixture.

Enhanced electrical stability of nitrate ligand-based hexaaqua complexes solution-processed ultrathin a-IGZO transistors

NASA Astrophysics Data System (ADS)

Choi, C.; Baek, Y.; Lee, B. M.; Kim, K. H.; Rim, Y. S.

2017-12-01

We report solution-processed, amorphous indium-gallium-zinc-oxide-based (a-IGZO-based) thin-film transistors (TFTs). Our proposed solution-processed a-IGZO films, using a simple spin-coating method, were formed through nitrate ligand-based metal complexes, and they were annealed at low temperature (250 °C) to achieve high-quality oxide films and devices. We investigated solution-processed a-IGZO TFTs with various thicknesses, ranging from 4 to 16 nm. The 4 nm-thick TFT films had smooth morphology and high-density, and they exhibited excellent performance, i.e. a high saturation mobility of 7.73  ±  0.44 cm2 V-1 s-1, a sub-threshold swing of 0.27 V dec-1, an on/off ratio of ~108, and a low threshold voltage of 3.10  ±  0.30 V. However, the performance of the TFTs degraded as the film thickness was increased. We further performed positive and negative bias stress tests to examine their electrical stability, and it was noted that the operating behavior of the devices was highly stable. Despite a small number of free charges, the high performance of the ultrathin a-IGZO TFTs was attributed to the small effect of the thickness of the channel, low bulk resistance, the quality of the a-IGZO/SiO2 interface, and high film density.

Removal of pharmaceutical residue in municipal wastewater by DAF (dissolved air flotation)-MBR (membrane bioreactor) and ozone oxidation.

PubMed

Choi, Miyoung; Choi, Dong Whan; Lee, Jung Yeol; Kim, Young Suk; Kim, Bun Su; Lee, Byoung Ho

2012-01-01

Growing attention is given to pharmaceutical residue in the water environment. It is known that pharmaceuticals are able to survive from a series of wastewater treatment processes. Concerns regarding pharmaceutical residues are attributed to the fact that they are being detected in water and sediment environment ubiquitously. Pharmaceutical treatment using a series of wastewater treatment processes of the DAF (dissolved air flotation)-MBR (membrane bioreactor)-ozone oxidation was conducted in the study. DAF, without addition of coagulant, could remove COD(cr) (chemical oxygen demand by Cr) up to over 70%, BOD 73%, SS 83%, T-N 55%, NH₄(+) 23%, and T-P 65% in influent of municipal wastewater. Average removal rates of water quality parameters by the DAF-MBR system were very high, e.g. COD(cr) 95.88%, BOD₅ 99.66%, COD(mn) (chemical oxygen demand by Mn) 93.63%, T-N 69.75%, NH₄-N 98.46%, T-P 78.23%, and SS 99.51%, which satisfy effluent water quality standards. Despite the high removal rate of the wastewater treatment system, pharmaceuticals were eliminated to be about 50-99% by the MBR system, depending on specific pharmaceuticals. Ibuprofen was well removed by MBR system up to over 95%, while removal rate of bezafibrate ranged between 50 and 90%. With over 5 mg/l of ozone oxidation, most pharmaceuticals which survived the DAF-MBR process were removed completely or resulted in very low survival rate within the range of few micrograms per litre. However, some pharmaceuticals such as bezafibrate and naproxen tended to be resistant to ozone oxidation.

Oxidative stress and food supplementation with antioxidants in therapy dogs.

PubMed

Sechi, Sara; Fiore, Filippo; Chiavolelli, Francesca; Dimauro, Corrado; Nudda, Anna; Cocco, Raffaella

2017-07-01

The objective of this study was to evaluate the ability of a long-term antioxidant-supplemented diet to regulate the oxidative stress and general health status of dogs involved in animal-assisted intervention (AAI) programs. Oxidative stress is a consequence of the accumulation of reactive oxygen species (ROS). Exercise-induced oxidative stress can increase muscle fatigue and fiber damage and eventually leads to impairment of the immune system. A randomized, placebo-controlled, crossover clinical evaluation was conducted with 11 healthy therapy dogs: 6 females and 5 males of different breeds and with a mean age of 2.7 ± 0.8 y (mean ± SEM). The dogs were divided into 2 groups, 1 fed a high quality commercial diet without antioxidants (CD) and the other a high quality commercial diet supplemented with antioxidants (SD) for 18 wk. After the first 18 wk, metabolic parameters, reactive oxygen metabolite-derivatives (d-ROMs), and biological antioxidant potential (BAP) levels were monitored and showed a significant reduction of d-ROMs, triglycerides, and creatinine values in the SD group ( P < 0.05) and a significant increase in amylase values in the CD group ( P < 0.01). At the end of this period, groups were crossed over and fed for another 18 wk. A significant decrease in amylase and glutamate pyruvate transaminase (GPT) values was observed in the CD and SD group, respectively ( P < 0.05). In conclusion, a controlled, balanced antioxidant diet may be a valid approach to restoring good cell metabolism and neutralizing excess free radicals in therapy dogs.

Oxidative stress and food supplementation with antioxidants in therapy dogs

PubMed Central

Sechi, Sara; Fiore, Filippo; Chiavolelli, Francesca; Dimauro, Corrado; Nudda, Anna; Cocco, Raffaella

2017-01-01

The objective of this study was to evaluate the ability of a long-term antioxidant-supplemented diet to regulate the oxidative stress and general health status of dogs involved in animal-assisted intervention (AAI) programs. Oxidative stress is a consequence of the accumulation of reactive oxygen species (ROS). Exercise-induced oxidative stress can increase muscle fatigue and fiber damage and eventually leads to impairment of the immune system. A randomized, placebo-controlled, crossover clinical evaluation was conducted with 11 healthy therapy dogs: 6 females and 5 males of different breeds and with a mean age of 2.7 ± 0.8 y (mean ± SEM). The dogs were divided into 2 groups, 1 fed a high quality commercial diet without antioxidants (CD) and the other a high quality commercial diet supplemented with antioxidants (SD) for 18 wk. After the first 18 wk, metabolic parameters, reactive oxygen metabolite-derivatives (d-ROMs), and biological antioxidant potential (BAP) levels were monitored and showed a significant reduction of d-ROMs, triglycerides, and creatinine values in the SD group (P < 0.05) and a significant increase in amylase values in the CD group (P < 0.01). At the end of this period, groups were crossed over and fed for another 18 wk. A significant decrease in amylase and glutamate pyruvate transaminase (GPT) values was observed in the CD and SD group, respectively (P < 0.05). In conclusion, a controlled, balanced antioxidant diet may be a valid approach to restoring good cell metabolism and neutralizing excess free radicals in therapy dogs. PMID:28725111

Oxidative potential of subway PM2.5

NASA Astrophysics Data System (ADS)

Moreno, Teresa; Kelly, Frank J.; Dunster, Chrissi; Oliete, Ana; Martins, Vânia; Reche, Cristina; Minguillón, Maria Cruz; Amato, Fulvio; Capdevila, Marta; de Miguel, Eladio; Querol, Xavier

2017-01-01

Air quality in subway systems is of interest not only because particulate matter (PM) concentrations can be high, but also because of the peculiarly metalliferous chemical character of the particles, most of which differ radically from those of outdoor ambient air. We report on the oxidative potential (OP) of PM2.5 samples collected in the Barcelona subway system in different types of stations. The PM chemical composition of these samples showed typically high concentrations of Fe, Total Carbon, Ba, Cu, Mn, Zn and Cr sourced from rail tracks, wheels, catenaries, brake pads and pantographs. Two toxicological indicators of oxidative activity, ascorbic acid (AA) oxidation (expressed as OPAA μg-1 or OPAA m-3) and glutathione (GSH) oxidation (expressed as OPGSH μg-1 or OPGSH m-3), showed low OP for all samples (compared with outdoor air) but considerable variation between stations (0.9-2.4 OPAA μg-1; 0.4-1.9 OPGSH μg-1). Results indicate that subway PM toxicity is not related to variations in PM2.5 concentrations produced by ventilation changes, tunnel works, or station design, but may be affected more by the presence of metallic trace elements such as Cu and Sb sourced from brakes and pantographs. The OP assays employed do not reveal toxic effects from the highly ferruginous component present in subway dust.

Synthesis of thin films and materials utilizing a gaseous catalyst

DOEpatents

Morse, Daniel E; Schwenzer, Birgit; Gomm, John R; Roth, Kristian M; Heiken, Brandon; Brutchey, Richard

2013-10-29

A method for the fabrication of nanostructured semiconducting, photoconductive, photovoltaic, optoelectronic and electrical battery thin films and materials at low temperature, with no molecular template and no organic contaminants. High-quality metal oxide semiconductor, photovoltaic and optoelectronic materials can be fabricated with nanometer-scale dimensions and high dopant densities through the use of low-temperature biologically inspired synthesis routes, without the use of any biological or biochemical templates.

Bioaugmentation for Aerobic Bioremediation of RDX Contaminated Groundwater

DTIC Science & Technology

2016-01-06

Subsequent higher concentration (15 to 24 mM) fructose additions during high carbon biostimulation in DW-1 and MW-28 resulted in a slight decrease in pH ...that has suitable transport properties and high RDX degradation rates for a given site may not be able to be developed; (2) the selected...phase; attached cells were not measured. Minimal secondary groundwater quality degradation pH , dissolved oxygen (O2), oxidation

Electrical Switching in Semiconductor-Metal Self-Assembled VO2 Disordered Metamaterial Coatings

PubMed Central

Kumar, Sunil; Maury, Francis; Bahlawane, Naoufal

2016-01-01

As a strongly correlated metal oxide, VO2 inspires several highly technological applications. The challenging reliable wafer-scale synthesis of high quality polycrystalline VO2 coatings is demonstrated on 4” Si taking advantage of the oxidative sintering of chemically vapor deposited VO2 films. This approach results in films with a semiconductor-metal transition (SMT) quality approaching that of the epitaxial counterpart. SMT occurs with an abrupt electrical resistivity change exceeding three orders of magnitude with a narrow hysteresis width. Spatially resolved infrared and Raman analyses evidence the self-assembly of VO2 disordered metamaterial, compresing monoclinic (M1 and M2) and rutile (R) domains, at the transition temperature region. The M2 mediation of the M1-R transition is spatially confined and related to the localized strain-stabilization of the M2 phase. The presence of the M2 phase is supposed to play a role as a minor semiconducting phase far above the SMT temperature. In terms of application, we show that the VO2 disordered self-assembly of M and R phases is highly stable and can be thermally triggered with high precision using short heating or cooling pulses with adjusted strengths. Such a control enables an accurate and tunable thermal control of the electrical switching. PMID:27883052

Lanthanide-based oxides and silicates for high-kappa gate dielectric applications

NASA Astrophysics Data System (ADS)

Jur, Jesse Stephen

The ability to improve performance of the high-end metal oxide semiconductor field effect transistor (MOSFET) is highly reliant on the dimensional scaling of such a device. In scaling, a decrease in dielectric thickness results in high current leakage between the electrode and the substrate by way of direct tunneling through the gate dielectric. Observation of a high leakage current when the standard gate dielectric, SiO2, is decreased below a thickness of 1.5 nm requires engineering of a replacement dielectric that is much more scalable. This high-kappa dielectric allows for a physically thicker oxide, reducing leakage current. Integration of select lanthanide-based oxides and silicates, in particular lanthanum oxide and silicate, into MOS gate stack devices is examined. The quality of the high-kappa dielectrics is monitored electrically to determine properties such as equivalent oxide thickness, leakage current density and defect densities. In addition, analytical characterization of the dielectric and the gate stack is provided to examine the materialistic significance to the change of the electrical properties of the devices. In this work, lanthanum oxide films have been deposited by thermal evaporation on to a pre-grown chemical oxide layer on silicon. It is observed that the SiO2 interfacial layer can be consumed by a low-temperature reaction with lanthanum oxide to produce a high-quality silicate. This is opposed to depositing lanthanum oxide directly on silicon, which can possibly favor silicide formation. The importance of oxygen regulation in the surrounding environment of the La2O3-SiO2 reaction-anneal is observed. By controlling the oxygen available during the reaction, SiO2 growth can be limited to achieve high stoichiometric ratios of La2O 3 to SiO2. As a result, MOS devices with an equivalent oxide thickness (EOT) of 5 A and a leakage current density of 5.0 A/cm 2 are attained. This data equals the best value achieved in this field and is a substantial improvement over SiO(N) dielectrics, allowing for increased device scaling. High-temperature processing, consistent with the source/drain activation anneal in MOSFET processing, is performed on lanthanum-silicate based MOS devices with Ta or TaN gate electrodes and a W metal capping layer. The thermal limit of Ta is observed to be less than 800°C, resulting in a phase transformation that can result in uncontrolled shifting of the MOS device flat-band voltage. TaN is observed to be more thermally stable (up to 1000°C) and results in an increase in the capacitance density suggesting that it impedes oxygen reaction with silicon to produce SiO2. It is later observed that a W metal capping layer can serve as a high-oxygen source, which results in an increased interfacial SiO2 formation. By limiting the oxygen content in the W capping layer and by utilizing a thermally stable TaN gate electrode, control over the electrical properties of the MOS device is acquired. To determine the stability of amorphous lanthanum-silicate in contact with investigated by means of back-side secondary ion mass spectroscopy profiling. The results are the first reported data showing that the lanthanum incorporated in the silica matrix doe not diffuse into the silicon substrate after high temperature processing. The decrease in the device effective work function (φM,eff ) observed in these samples is examined in detail. First, as a La 2O3 capping layer on HfSiO(N), the shift yields ideal-φ M,eff values for nMOSFET deices (4.0 eV) that were previously inaccessible. Other lanthanide oxides (Dy, Ho and Yb) used as capping layers show similar effects. It is also shown that tuning of φM,eff can be realized by controlling the extent of lanthanide-silicate formation. This research, conducted in conjunction with SEMATECH and the SRC, represents a significant technological advancement in realizing 45 and sub-45 nm MOSFET device nodes.

Temperature of frozen storage affects the nature and consequences of protein oxidation in beef patties.

PubMed

Utrera, Mariana; Morcuende, David; Estévez, Mario

2014-03-01

The effect of three frozen storage temperatures (-8, -18 and -80 °C) on protein oxidation in beef patties was studied through the analysis of novel oxidation markers. Additionally, the connection between lipid and protein oxidation and the impact of the latter on particular quality traits (water holding capacity, color and texture) of subsequently processed beef patties (cooking/cold-stored) were investigated. Protein oxidation was measured as the loss of tryptophan fluorescence and formation of diverse lysine oxidation products (α-aminoadipic semialdehyde, α-aminoadipic acid and Schiff bases). Lipid oxidation was assessed by levels of thiobarbituric acid reactive substances and hexanal. A significant effect of storage temperature on protein oxidation was detected. Frozen storage increased the susceptibility of meat proteins to undergo further oxidation during processing. Timely interactions were found between lipid and protein oxidation. Plausible mechanisms by which oxidative damage to proteins may have an impact in particular quality traits are thoroughly discussed. © 2013.

IMPACTS OF ANTIFOAM ADDITIONS AND ARGON BUBBLING ON DEFENSE WASTE PROCESSING FACILITY REDUCTION/OXIDATION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jantzen, C.; Johnson, F.

2012-06-05

During melting of HLW glass, the REDOX of the melt pool cannot be measured. Therefore, the Fe{sup +2}/{Sigma}Fe ratio in the glass poured from the melter must be related to melter feed organic and oxidant concentrations to ensure production of a high quality glass without impacting production rate (e.g., foaming) or melter life (e.g., metal formation and accumulation). A production facility such as the Defense Waste Processing Facility (DWPF) cannot wait until the melt or waste glass has been made to assess its acceptability, since by then no further changes to the glass composition and acceptability are possible. therefore, themore » acceptability decision is made on the upstream process, rather than on the downstream melt or glass product. That is, it is based on 'feed foward' statistical process control (SPC) rather than statistical quality control (SQC). In SPC, the feed composition to the melter is controlled prior to vitrification. Use of the DWPF REDOX model has controlled the balanjce of feed reductants and oxidants in the Sludge Receipt and Adjustment Tank (SRAT). Once the alkali/alkaline earth salts (both reduced and oxidized) are formed during reflux in the SRAT, the REDOX can only change if (1) additional reductants or oxidants are added to the SRAT, the Slurry Mix Evaporator (SME), or the Melter Feed Tank (MFT) or (2) if the melt pool is bubble dwith an oxidizing gas or sparging gas that imposes a different REDOX target than the chemical balance set during reflux in the SRAT.« less

Development of rigorous fatty acid near-infrared spectroscopy quantitation methods in support of soybean oil improvement

USDA-ARS?s Scientific Manuscript database

The seed of soybean (Glycine max L. Merr) is a valuable source of high quality edible oil and protein. Despite dramatic breeding gains over the past 80 years, soybean seed oil continues to be oxidatively unstable. Until recently, the majority of soybean oil underwent partial chemical hydrogenation. ...

Laser Crystal

NASA Technical Reports Server (NTRS)

1998-01-01

Lightning Optical Corporation, under an SBIR (Small Business Innovative Research) agreement with Langley Research Center, manufactures oxide and fluoride laser gain crystals, as well as various nonlinear materials. The ultimate result of this research program is the commercial availability in the marketplace of a reliable source of high-quality, damage resistant laser material, primarily for diode-pumping applications.

Olive oil quality and ripening in super-high-density Arbequina orchard.

PubMed

Benito, Marta; Lasa, José Manuel; Gracia, Pilar; Oria, Rosa; Abenoza, María; Varona, Luis; Sánchez-Gimeno, Ana Cristina

2013-07-01

The aim of this work was to evaluate the evolution of the quality of extra virgin olive oil obtained from a super-high-density Arbequina orchard, under a drip irrigation system, throughout the ripening process. For this objective, physicochemical, nutritional and sensory parameters were studied. In addition, the oxidative stability, pigment content and colour evolution of olive oil were analysed during the ripening process. Free acidity increased slightly throughout the ripening process, while peroxide value and extinction coefficient decreased. Total phenol content and oxidative stability showed a similar trend, increasing at the beginning of ripening up to a maximum and thereafter decreasing. α-Tocopherol and pigment contents decreased with ripening, leading to changes in colour coordinates. Sensory parameters were correlated with total phenol content, following a similar trend throughout the maturation process. By sampling and monitoring the ripeness index weekly, it would be possible to determine an optimal harvesting time for olives according to the industrial yield and the physicochemical, nutritional and sensory properties of the olive oil. © 2012 Society of Chemical Industry.

Oxidation and textural characteristics of butter and ice cream with modified fatty acid profiles.

PubMed

Gonzalez, S; Duncan, S E; O'Keefe, S F; Sumner, S S; Herbein, J H

2003-01-01

The primary objective of this study was to evaluate oxidation and firmness of butter and ice cream made with modified milkfat containing enhanced amounts of linoleic acid or oleic acid. The influence of the fatty acid profile of the HO milkfat relating to product properties as compared with the influence the fatty acid profile of the HL milkfat was the main focus of the research. Altering the degree of unsaturation in milkfat may affect melting characteristics and oxidation rates, leading to quality issues in dairy products. Three milkfat compositions (high-oleic, high-linoleic, and control) were obtained by modifying the diets of Holstein cows. Ice cream and butter were processed from milkfat obtained from cows in each dietary group. Butter and ice cream samples were analyzed to determine fatty acid profile and firmness. High-oleic milkfat resulted in a softer butter. Solid fat index of high-oleic and high-linoleic milkfat was lower than the control. Control ice cream mix had higher viscosity compared with high-oleic and high-linoleic, but firmness of all ice creams was similar when measured between -17 and -13 degrees C. Nutritional and textural properties of butter and ice cream can be improved by modifying the diets of cows.

One-Step Synthesis of Monodisperse In-Doped ZnO Nanocrystals

NASA Astrophysics Data System (ADS)

Wang, Qing Ling; Yang, Ye Feng; He, Hai Ping; Chen, Dong Dong; Ye, Zhi Zhen; Jin, Yi Zheng

2010-05-01

A method for the synthesis of high quality indium-doped zinc oxide (In-doped ZnO) nanocrystals was developed using a one-step ester elimination reaction based on alcoholysis of metal carboxylate salts. The resulting nearly monodisperse nanocrystals are well-crystallized with typically crystal structure identical to that of wurtzite type of ZnO. Structural, optical, and elemental analyses on the products indicate the incorporation of indium into the host ZnO lattices. The individual nanocrystals with cubic structures were observed in the 5% In-ZnO reaction, due to the relatively high reactivity of indium precursors. Our study would provide further insights for the growth of doped oxide nanocrystals, and deepen the understanding of doping process in colloidal nanocrystal syntheses.

Quality characteristics of fried lamb nuggets from low-value meat cuts: Effect of formulation and freezing storage.

PubMed

Medina, Milagros; Antequera, Teresa; Ruiz, Jorge; Jiménez-Martín, Estefanía; Pérez-Palacios, Trinidad

2015-10-01

This study revealed the possibility of manufacturing prefried lamb nuggets from low-value cuts (flank) and evaluated the effect of formulation (50:50 vs. 20:80 of leg/flank cuts) and freezing (-20 ℃ for two months) on different quality parameters. Frying process produced a decrease of water content, an increase in lipid oxidation indicators, and an intense browning of nuggets surface. The use of flank up to a 75% of the total meat in the formula led to higher fat contents and higher polyunsaturated fatty acid proportions in fried nuggets. This made them more prone to get oxidized during the freezing storage and subsequent final frying. Nuggets with a higher proportion of flank also showed lower shear force values. However, nuggets with both formulations showed similar sensory acceptance. Freezing storage of lamb meat nuggets for two months increased the levels of lipid oxidation indicators, but again not to a level high enough to influence the sensory perception by consumers. So that, frozen nuggets from both formulations showed similar consumer acceptance to freshly produced ones with quite good scores (3.46-3.86 out of 5). Thus, low-value lamb cuts are suitable for being processed into highly acceptable prefried frozen lamb nuggets, which constitutes an opportunity for adding value to the whole lamb value chain. © The Author(s) 2014.

Boar management and semen handling factors affect the quality of boar extended semen.

PubMed

Lopez Rodriguez, Alfonso; Van Soom, Ann; Arsenakis, Ioannis; Maes, Dominiek

2017-01-01

Artificial insemination (AI) is the preferred method for reproduction in the majority of the intensive pig production systems Worldwide. To this end, fresh extended ready-to-use semen doses are either purchased from AI-centres or produced by boars kept on-farm. For profitable semen production, it is necessary to obtain a maximum amount of high quality semen from each boar. This paper reviews current knowledge on factors that may affect semen quality by influencing the boar or the semen during processing. Genetic markers could be used for early detection of boars with the highest fertility potential. Genetic selection for fast growth might jeopardize semen quality. Early detection of boars no longer fit for semen production might be possible by ultrasonography of the testes. Seasonal variation in sperm quality could be associated with changes in photoperiod and heat stress during summer. Comfortable housing, with appropiate bedding material to avoid locomotion problems is essential. In some areas, cooling systems may be necessary to avoid heat stress. The sperm quality can be manipulated by feeding strategies aiming, for instance, to increase sperm resistance to oxidative stress and extend storage duration. High collection frequency will negatively influence sperm quality. Also, if collection is not hygienically performed it will result in bacterial contamination of the semen doses. The concern over bacterial contamination has risen not only because of its negative effect on semen quality but also due to the detection of antimicrobial resistance in isolates from extended semen. Moreover, bacterial and viral pathogens must be monitored because they affect semen production and quality and constitute a risk of herd infection. During processing, boar sperm are submitted to many stress factors that can cause oxidative stress and capacitation-like changes potentially reducing their fertility potential. Dilution rate or dilution temperature affects the quality of the semen doses. Some packaging might preserve semen better than others and some plastic components might be toxic for sperm. Standard operation procedures and quality assurance systems in AI centres are needed.

Wafer-scale growth of VO2 thin films using a combinatorial approach

PubMed Central

Zhang, Hai-Tian; Zhang, Lei; Mukherjee, Debangshu; Zheng, Yuan-Xia; Haislmaier, Ryan C.; Alem, Nasim; Engel-Herbert, Roman

2015-01-01

Transition metal oxides offer functional properties beyond conventional semiconductors. Bridging the gap between the fundamental research frontier in oxide electronics and their realization in commercial devices demands a wafer-scale growth approach for high-quality transition metal oxide thin films. Such a method requires excellent control over the transition metal valence state to avoid performance deterioration, which has been proved challenging. Here we present a scalable growth approach that enables a precise valence state control. By creating an oxygen activity gradient across the wafer, a continuous valence state library is established to directly identify the optimal growth condition. Single-crystalline VO2 thin films have been grown on wafer scale, exhibiting more than four orders of magnitude change in resistivity across the metal-to-insulator transition. It is demonstrated that ‘electronic grade' transition metal oxide films can be realized on a large scale using a combinatorial growth approach, which can be extended to other multivalent oxide systems. PMID:26450653

Characterisation of cold plasma treated beef and dairy lipids using spectroscopic and chromatographic methods.

PubMed

Sarangapani, Chaitanya; Ryan Keogh, David; Dunne, Julie; Bourke, Paula; Cullen, P J

2017-11-15

The efficacy of cold plasma for inactivation of food-borne pathogens in foods is established. However, insights on cold plasma-food interactions in terms of quality effects, particularly for oils and fats, are sparse. This study evaluated plasma-induced lipid oxidation of model matrices, namely dairy and meat fats. Product characterisation was performed using FTIR, 1 H NMR and chromatographic techniques. The oxidation of lipids by cold plasma followed the Criegee mechanism and typical oxidation products identified included ozonides, aldehydes (hexanal, pentenal, nonanal and nonenal) and carboxylic acids (9-oxononanoic acid, octanoic acid, nonanoic acid), along with hydroperoxides (9- and 13-hydroperoxy-octadecadienoylglycerol species). However, these oxidation products were only identified following extended treatment times of 30min and were also a function of applied voltage level. Understanding cold plasma interactions with food lipids and the critical parameters governing lipid oxidation is required prior to the industrial adoption of this technology for food products with high fat contents. Copyright © 2017 Elsevier Ltd. All rights reserved.

Growth and characterization of β-Ga2O3 thin films by molecular beam epitaxy for deep-UV photodetectors

NASA Astrophysics Data System (ADS)

Ghose, Susmita; Rahman, Shafiqur; Hong, Liang; Rojas-Ramirez, Juan Salvador; Jin, Hanbyul; Park, Kibog; Klie, Robert; Droopad, Ravi

2017-09-01

The growth of high quality epitaxial beta-gallium oxide (β-Ga2O3) using a compound source by molecular beam epitaxy has been demonstrated on c-plane sapphire (Al2O3) substrates. The compound source provides oxidized gallium molecules in addition to oxygen when heated from an iridium crucible in a high temperature effusion cell enabling a lower heat of formation for the growth of Ga2O3, resulting in a more efficient growth process. This source also enabled the growth of crystalline β-Ga2O3 without the need for additional oxygen. The influence of the substrate temperatures on the crystal structure and quality, chemical bonding, surface morphology, and optical properties has been systematically evaluated by x-ray diffraction, scanning transmission electron microscopy, x-ray photoelectron spectroscopy, atomic force microscopy, spectroscopic ellipsometry, and UV-vis spectroscopy. Under optimized growth conditions, all films exhibited pure (" separators="|2 ¯01 ) oriented β-Ga2O3 thin films with six-fold rotational symmetry when grown on a sapphire substrate. The thin films demonstrated significant absorption in the deep-ultraviolet (UV) region with an optical bandgap around 5.0 eV and a refractive index of 1.9. A deep-UV photodetector fabricated on the high quality β-Ga2O3 thin film exhibits high resistance and small dark current (4.25 nA) with expected photoresponse for 254 nm UV light irradiation suggesting that the material grown using the compound source is a potential candidate for deep-ultraviolet photodetectors.

Combined effects of gamma radiation doses and sodium nitrite content on the lipid oxidation and color of mortadella.

PubMed

Dutra, Monalisa Pereira; Cardoso, Giselle Pereira; Fontes, Paulo Rogério; Silva, Douglas Roberto Guimarães; Pereira, Marcio Tadeu; Ramos, Alcinéia de Lemos Souza; Ramos, Eduardo Mendes

2017-12-15

The effects of different doses of gamma radiation (0-20kGy) on the color and lipid oxidation of mortadella prepared with increasing nitrite levels (0-300ppm) were evaluated using a central composite rotatable design. Higher radiation doses increased the redox potential, promoted the lipid oxidation and elevating the hue color of the mortadellas. Nevertheless, higher addition of sodium nitrite elevated the residual nitrite content, reduced the lipid oxidation and promoted the increase of redness and the reduce of hue color of the mortadellas, regardless of the radiation dose applied. Nitrite addition had a greater effect than irradiation on the quality parameters evaluated, and even at low levels (∼75ppm), its use decreased the deleterious effects of irradiation at doses as high as 20kGy. Copyright © 2017 Elsevier Ltd. All rights reserved.

Identification of vacancy defect complexes in transparent semiconducting oxides ZnO, In2O3 and SnO2.

PubMed

Makkonen, Ilja; Korhonen, Esa; Prozheeva, Vera; Tuomisto, Filip

2016-06-08

Positron annihilation spectroscopy, when combined with supporting high-quality modeling of positron states and annihilation in matter, is a powerful tool for detailed defect identification of vacancy-type defects in semiconductors and oxides. Here we demonstrate that the Doppler broadening of the positron annihilation radiation is a very sensitive means for observing the oxygen environment around cation vacancies, the main open-volume defects trapping positrons in measurements made for transparent semiconducting oxides. Changes in the positron annihilation signal due to external manipulation such as irradiation and annealing can be correlated with the associated changes in the sizes of the detected vacancy clusters. Our examples for ZnO, In2O3 and SnO2 demonstrate that oxygen vacancies in oxides can be detected directly using positron annihilation spectroscopy when they are complexed with cation vacancies.

Identification of vacancy defect complexes in transparent semiconducting oxides ZnO, In2O3 and SnO2

NASA Astrophysics Data System (ADS)

Makkonen, Ilja; Korhonen, Esa; Prozheeva, Vera; Tuomisto, Filip

2016-06-01

Positron annihilation spectroscopy, when combined with supporting high-quality modeling of positron states and annihilation in matter, is a powerful tool for detailed defect identification of vacancy-type defects in semiconductors and oxides. Here we demonstrate that the Doppler broadening of the positron annihilation radiation is a very sensitive means for observing the oxygen environment around cation vacancies, the main open-volume defects trapping positrons in measurements made for transparent semiconducting oxides. Changes in the positron annihilation signal due to external manipulation such as irradiation and annealing can be correlated with the associated changes in the sizes of the detected vacancy clusters. Our examples for ZnO, In2O3 and SnO2 demonstrate that oxygen vacancies in oxides can be detected directly using positron annihilation spectroscopy when they are complexed with cation vacancies.

Low-voltage high-performance organic thin film transistors with a thermally annealed polystyrene/hafnium oxide dielectric

NASA Astrophysics Data System (ADS)

Wang, Ying; Acton, Orb; Ting, Guy; Weidner, Tobias; Ma, Hong; Castner, David G.; Jen, Alex K.-Y.

2009-12-01

Low-voltage pentacene-based organic thin film transistors (OTFTs) are demonstrated with polystyrene (PS)/hafnium oxide (HfOx) hybrid dielectrics. Thermal annealing of PS films on HfOx at 120 °C (PS-120) induces a flatter orientation of the phenyl groups (tilt angle 65°) at the surface compared to PS films without annealing (PS-RT) (tilt angle 31°). The flatter phenyl group orientation leads to better matching of surface energy between pentacene and PS. Pentacene deposited on PS-120 display higher quality thin films with larger grain sizes and higher crystallinity. Pentacene OTFTs with PS-120/HfOx hybrid dielectrics can operate at low-voltage (<3 V) with high field-effect mobilities (1 cm2/V s), high on/off current ratios (106), and low subthreshold slopes (100 mV/dec).

Rear-side picosecond laser ablation of indium tin oxide micro-grooves

NASA Astrophysics Data System (ADS)

Liu, Peng; Wang, Wenjun; Mei, Xuesong; Liu, Bin; Zhao, Wanqin

2015-06-01

A comparative study of the fabrication of micro-grooves in indium tin oxide films by picosecond laser ablation for application in thin film solar cells is presented, evaluating the variation of different process parameters. Compared with traditional front-side ablation, rear-side ablation results in thinner grooves with varying laser power at a certain scan speed. In particular, and in contrast to front-side ablation, the width of the micro-grooves remains unchanged when the scan speed was changed. Thus, the micro-groove quality can be optimized by adjusting the scan speed while the groove width would not be affected. Furthermore, high-quality micro-grooves with ripple free surfaces and steep sidewalls could only be achieved when applying rear-side ablation. Finally, the formation mechanism of micro-cracks on the groove rims during rear-side ablation is analyzed and the cracks can be almost entirely eliminated by an optimization of the scan speed.

Updated model assessment of pollution at major U. S. airports

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yamartino, R.J.; Rote, D.M.

1979-02-01

The air quality impact of aircraft at and around Los Angeles International Airport (LAX) was simulated for hours of peak aircraft operation and 'worst case' pollutant dispersion conditions by using an updated version of the Argonne Airport Vicinity Air Pollution model; field programs at LAX, O'Hara, and John F. Kennedy International Airports determined the 'worst case' conditions. Maximum carbon monoxide concentrations at LAX were low relative to National Ambient Air Quality Standards; relatively high and widespread hydrocarbon concentrations indicated that aircraft emissions may aggravate oxidant problems near the airport; nitrogen oxide concentrations were close to the levels set in proposedmore » standards. Data on typical time-in-mode for departing and arriving aircraft, the 8/4/77 diurnal variation in airport activity, and carbon monoxide concentration isopleths are given, and the update factors in the model are discussed.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhu, Yuanyuan; Browning, Nigel D.

As gas-solid heterogeneous catalytic reactions are molecular in nature, a full mechanistic understanding of the process requires atomic scale characterization under realistic operating conditions. While atomic resolution imaging has become a routine in modern high-vacuum (scanning) transmission electron microscopy ((S)TEM), both image quality and resolution nominally degrade when reaction gases are introduced. In this work, we systematically assess the effects of different gases at various pressures on the quality and resolution of images obtained at room temperature in the annular dark field STEM imaging mode using a differentially pumped (DP) gas cell. This imaging mode is largely free from inelasticmore » scattering effects induced by the presence of gases and retains good imaging properties over a wide range of gas mass/pressures. We demonstrate the application of the ESTEM with atomic resolution images of a complex oxide alkane oxidation catalyst MoVNbTeOx (M1) immersed in light and heavy gas environments.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhu, Yuanyuan; Browning, Nigel D.

As gas-solid heterogeneous catalytic reactions are molecular in nature, a full mechanistic understanding of the process requires atomic scale characterization under realistic operating conditions. While atomic resolution imaging has become a routine in modern high-vacuum (scanning) transmission electron microscopy ((S)TEM), both image quality and resolution nominally degrade when reaction gases are introduced. In this work, we systematically assess the effects of different gases at various pressures on the quality and resolution of images obtained at room temperature in the annular dark field STEM imaging mode using a differentially pumped (DP) gas cell. This imaging mode is largely free from inelasticmore » scattering effects induced by the presence of gases and retains good imaging properties over a wide range of gas mass/pressures. Furthermore, we demonstrate the application of the ESTEM with atomic resolution images of a complex oxide alkane oxidation catalyst MoVNbTeOx (M1) immersed in light and heavy gas environments.« less

Trends in primary NO2 and exhaust PM emissions from road traffic for the period 2000-2020 and implications for air quality and health in the Netherlands

NASA Astrophysics Data System (ADS)

Keuken, M. P.; Roemer, M. G. M.; Zandveld, P.; Verbeek, R. P.; Velders, G. J. M.

2012-07-01

Application of an oxidation catalyst mainly by diesel-fuelled passenger cars reduces harmful exhaust emissions of particulate matter (PM). As a side effect, the primary NO2/NOx emission ratio by these vehicles increased from 10% in 2000 (before the introduction of the oxidation catalyst) to between 55% and 70% in 2010. The impact of this evolution in traffic emissions was studied from both a health and a regulatory perspective. Primary NO2 emissions from road traffic in the Netherlands is expected to increase from 8 kt in 2000 to 15 kt by 2015 and subsequently to decrease to 9 kt by 2020. Meanwhile, exhaust PM emissions from road traffic in the Netherlands will decrease from 7 kt in 2000 to 3 kt by 2020. The impact of exhaust PM on air quality and health was assessed according to the mass concentrations of elemental carbon (EC) in ambient air, as EC is a more sensitive indicator than PM. Monitoring data on the NO2/EC concentration ratios near road traffic between 2000 and 2010 indicate no significant change in ambient air quality. This indicates that health effects in epidemiological studies associated with long-term exposure to NO2 concentrations are still valid. The health impact from the introduction of the oxidation catalyst was assessed by comparing the relatively higher NO2 ("cost") and lower EC ("benefit") concentrations at street locations. "Relative" refers to traffic emissions in situations "with" and "without" the oxidation catalyst being introduced. The cost-benefit ratio in 2010 was in balance, but benefits are expected to outweigh costs by 2015 and 2020. It is concluded that the application of oxidation catalysts is beneficial from a health perspective, but from a regulatory perspective it complicates compliance with the average annual limit value of NO2. This indicates that additional local measures may be required in order to meet air quality standards at locations with high traffic intensities.

Laser Surface Treatment of Sintered Alumina

NASA Astrophysics Data System (ADS)

Hagemann, R.; Noelke, C.; Kaierle, S.; Wesling, V.

Sintered alumina ceramics are used as refractory materials for industrial aluminum furnaces. In this environment the ceramic surface is in permanent contact with molten aluminum resulting in deposition of oxidic material on its surface. Consequently, a lower volume capacity as well as thermal efficiency of the furnaces follows. To reduce oxidic adherence of the ceramic material, two laser-based surface treatment processes were investigated: a powder- based single-step laser cladding and a laser surface remelting. Main objective is to achieve an improved surface quality of the ceramic material considering the industrial requirements as a high process speed.

Electronic and magnetic properties of epitaxial SrRh O 3 films

DOE PAGES

Nichols, John A.; Yuk, Simuck F.; Sohn, Changhee; ...

2017-06-16

The strong interplay of fundamental order parameters in complex oxides is known to give rise to exotic physical phenomena. The 4$d$ transition-metal oxide SrRh O 3 has generated much interest, but advances have been hindered by difficulties in preparing single-crystalline phases. Here we epitaxially stabilize high-quality single-crystalline SrRh O 3 films and investigate their structural, electronic, and magnetic properties. Lastly, we determine that their properties significantly differ from the paramagnetic metallic ground state that governs bulk samples and are strongly related to rotations of Rh O 6 octahedra.

Zinc oxide hollow microstructures and nanostructures formed under hydrothermal conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dem'yanets, L. N., E-mail: demianets@ns.crys.ras.ru; Artemov, V. V.; Li, L. E.

Zinc oxide low-dimensional hollow structures in the form of hexagonal plates with holes at the center of the {l_brace}0001{r_brace} facets are synthesized in the course of the low-temperature interaction of ZnO precursors with aqueous solutions of potassium fluoride under hydrothermal conditions. Crystals have the shape of single-walled or multiwalled 'nuts.' The high optical quality of the structures is confirmed by cathodoluminescence data at room temperature. The mechanism of the formation of ZnO 'nanonuts' and products of the interaction of the ZnO precursors with KF is proposed.

Direct reduction processes for titanium oxide in molten salt

NASA Astrophysics Data System (ADS)

Suzuki, Ryosuke O.

2007-02-01

Molten salt electrolysis using CaCl2 is employed to produce pure titanium and its alloys directly from TiO2 and a mixture of elemental oxides, respectively, as an alternate to the Kroll process. This is because CaO, which is a reduction by-product, is highly soluble in CaCl2. Good-quality titanium containing only a small amount of residual oxygen has been successfully produced and scaled to industrial levels. Thermochemical and electrochemical bases are reviewed to optimize the process conditions. Several processes using molten salt are being examined for future progress in titanium processing.

Synthesis and Properties of Iron Oxide Particles Prepared by Hidrothermal Method

NASA Astrophysics Data System (ADS)

Saragi, T.; Santika, A. S.; Permana, B.; Syakir, N.; Kartawidjaja, M.; Risdiana

2017-05-01

Iron oxide of hematite (α-Fe2O3) has been successfully synthesized by hydrothermal method. The starting materials were Fe(NO3)3.9H2O, 2-methoxyethanol, diethanolamine and n-hexane. The optical, morphology and crystal structure were measured by UV-VIS, TEM and XRD, respectively. From UV-VIS measurement, it was found that the band-gap of sample was 4.17 eV. The morphology of particle was plate-like form. The sample which sintered at 1100°C has high quality crystal with hexagonal structure of α-Fe2O3 phase.

A Systematic Review Evaluating the Effect of Vitamin B6 on Semen Quality.

PubMed

Banihani, Saleem Ali

2017-12-30

This review systematically discusses and summarizes the effect of vitamin B6 on semen quality. To achieve this contribution, we searched the PubMed, Scopus, and Web of Science databases for English language papers from 1984 through 2017 using the key words "sperm" versus "Vitamin B6", "pyridoxine", and "pyridoxal". Also, the references from selected published papers were included, only if relevant. To date, as revealed by rodent studies, high doses of vitamin B6 impair semen quality and sperm parameters. While in humans, it is suggested, but not yet directly approved, that seminal vitamin B6 levels may alter sperm quality (i.e., sperm quantity and quality), and that vitamin B6 deficiency may trigger the chemical toxicity to sperm (i.e., hyperhomocysteinemia, oxidative injury). The adverse effect of vitamin B6, when used at high doses, has been revealed in experimental animals, but not yet directly approved in humans. Consequently, in vitro studies on human ejaculate as well as clinical studies that investigate the direct effect of vitamin B6 on semen quality seem very significant.

Evaluation of the Catalytic Activity and Cytotoxicity of Palladium Nanocubes. The Role of Oxygen

PubMed Central

Dahal, Eshan; Curtiss, Jessica; Subedi, Deepak; Chen, Gen; Houston, Jessica P.; Smirnov, Sergei

2015-01-01

Recently it has been reported that palladium nanocubes (PdNC) are capable of generating singlet oxygen without photo-excitation simply via chemisorption of molecular oxygen on its surface. Such a trait would make PdNC a highly versatile catalyst suitable in organic synthesis and a Reactive Oxygen Species (ROS) inducing cancer treatment reagent. Here we thoroughly investigated the catalytic activity of PdNC with respect to their ability to produce singlet oxygen and to oxidize 3,5,3′,5′-tetramethyl-benzidine (TMB), as well as, analyzed the cytotoxic properties of PdNC on HeLa cells. Our findings showed no evidence of singlet oxygen production by PdNC. The nanocubes’ activity is not necessarily linked to activation of oxygen. The oxidation of substrate on PdNC can be a first step followed by PdNC regeneration with oxygen or other oxidant. The catalytic activity of PdNC towards oxidation of TMB is very high and shows direct two-electrons oxidation when the surface of PdNC is clean and the ratio of TMB/PdNC is not very high. Sequential one electron oxidation is observed when the pristine quality of PdNC surface is compromised by serum or uncontrolled impurities and/or the ratio of TMB/PdNC is high. Clean PdNC in serum-free media efficiently induce apoptosis of HeLa cells. It is the primary route of cell death and is associated with hyperpolarization of mitochondria, contrary to a common mitochondrial depolarization initiated by ROS. Again, the effects are very sensitive to how well the pristine surface of PdNC is preserved, suggesting that PdNC can be used as an apoptosis inducing agent but only with appropriate drug delivery system. PMID:25886644

Experimental and theoretical study of the electronic structure of single-crystal BaBiO3

NASA Astrophysics Data System (ADS)

Balandeh, Shadi; Green, Robert J.; Foyevtsova, Kateryna; Chi, Shun; Foyevtsov, Oleksandr; Li, Fengmiao; Sawatzky, George A.

2017-10-01

High quality single crystals of BaBiO3 were grown by congruent melting technique and characterized with x-ray diffraction, x-ray photoemission, and transport property studies. The perovskite oxide BaBiO3 is a negative charge transfer gap high Tc oxide parent superconducting compound exhibiting self-doping of holes into the oxygen 2 p band. We study the low energy scale valence and conduction bands in detail from both a theoretical perspective as well as through x ray, absorption/emission, and photoelectron spectroscopies. X-ray spectroscopy verifies the results of density functional theory (DFT) regarding the overall band structure featuring strong O 2 p character of the empty antibonding combination of the hybridized Bi 6 s and O 2 p states. From the analysis of the core level line shapes we conclude that the dominant O 2 p -Bi 6 s hybridization energy scale determines the low energy scale electronic structure. This analysis provides further insight into the importance of self-doped oxygen 2 p states in this high Tc family of oxides.

Preparation of atomically flat rutile TiO 2(001) surfaces for oxide film growth

DOE PAGES

Wang, Yang; Lee, Shinbuhm; Vilmercati, P.; ...

2016-01-01

The availability of low-index rutile TiO 2 single crystal substrates with atomically flat surfaces is essential for enabling epitaxialgrowth of rutile transition metal oxide films. The high surface energy of the rutile (001) surface often leads to surface faceting, which precludes the sputter and annealing treatment commonly used for the preparation of clean and atomically flat TiO 2(110) substrate surfaces. In this work, we reveal that stable and atomically flat rutile TiO 2(001) surfaces can be prepared with an atomically ordered reconstructedsurface already during a furnace annealing treatment in air. We tentatively ascribe this result to the decrease in surfacemore » energy associated with the surface reconstruction, which removes the driving force for faceting. Despite the narrow temperature window where this morphology can initially be formed, we demonstrate that it persists in homoepitaxialgrowth of TiO 2(001) thin films. The stabilization of surface reconstructions that prevent faceting of high-surface-energy crystal faces may offer a promising avenue towards the realization of a wider range of high quality epitaxial transition metal oxide heterostructures.« less

The effect of irradiation in the quality of the avocado frozen pulp

NASA Astrophysics Data System (ADS)

Valdivia, Ma. Ángeles; Bustos, Ma. Emilia; Ruiz, Javier; Ruiz, Luisa F.

2002-03-01

The quality of frozen avocado pulp irradiated with 60Co gamma rays at doses of: 0.5, 1.0, 1.5, and 2.5 kGy, was studied. These are possible doses for reducing the content of bacteria Listeria monocytogenes by 1-4 log cycles. The study principally consisted of weekly evaluations of damages caused in lipids and chlorophyll pigment over a period of one year. No significant differences were found in either hydrolysis rancidity or in the oxidative rancidity for any of the doses. The concentrations of fatty acids and peroxides were below those established by Codex Alimentarius. This means that the quality of the oil in the frozen avocado pulp remains acceptable. The kinetic model for the oxidative rancidity is of first order and the shelf life of the product is of about 120 weeks. The concentrations of the fatty acids and of malondialdehyde were not high enough to produce off-flavors. It was also determined that the radiation doses did not influence the chemistry of the chlorophyll. The results were confirmed by the panelists, who accepted irradiated frozen pulp at the highest radiation dose.

Thermal Catalytic Oxidation of Airborne Contaminants by a Reactor Using Ultra-Short Channel Length, Monolithic Catalyst Substrates

NASA Technical Reports Server (NTRS)

Perry, J. L.; Tomes, K. M.; Tatara, J. D.

2005-01-01

Contaminated air, whether in a crewed spacecraft cabin or terrestrial work and living spaces, is a pervasive problem affecting human health, performance, and well being. The need for highly effective, economical air quality processes spans a wide range of terrestrial and space flight applications. Typically, air quality control processes rely on absorption-based processes. Most industrial packed-bed adsorption processes use activated carbon. Once saturated, the carbon is either dumped or regenerated. In either case, the dumped carbon and concentrated waste streams constitute a hazardous waste that must be handled safely while minimizing environmental impact. Thermal catalytic oxidation processes designed to address waste handling issues are moving to the forefront of cleaner air quality control and process gas decontamination processes. Careful consideration in designing the catalyst substrate and reactor can lead to more complete contaminant destruction and poisoning resistance. Maintenance improvements leading to reduced waste handling and process downtime can also be realized. Performance of a prototype thermal catalytic reaction based on ultra-short waste channel, monolith catalyst substrate design, under a variety of process flow and contaminant loading conditions, is discussed.

GaN as an interfacial passivation layer: tuning band offset and removing fermi level pinning for III-V MOS devices.

PubMed

Zhang, Zhaofu; Cao, Ruyue; Wang, Changhong; Li, Hao-Bo; Dong, Hong; Wang, Wei-Hua; Lu, Feng; Cheng, Yahui; Xie, Xinjian; Liu, Hui; Cho, Kyeongjae; Wallace, Robert; Wang, Weichao

2015-03-11

The use of an interfacial passivation layer is one important strategy for achieving a high quality interface between high-k and III-V materials integrated into high-mobility metal-oxide-semiconductor field-effect transistor (MOSFET) devices. Here, we propose gallium nitride (GaN) as the interfacial layer between III-V materials and hafnium oxide (HfO2). Utilizing first-principles calculations, we explore the structural and electronic properties of the GaN/HfO2 interface with respect to the interfacial oxygen contents. In the O-rich condition, an O8 interface (eight oxygen atoms at the interface, corresponding to 100% oxygen concentration) displays the most stability. By reducing the interfacial O concentration from 100 to 25%, we find that the interface formation energy increases; when sublayer oxygen vacancies exist, the interface becomes even less stable compared with O8. The band offset is also observed to be highly dependent on the interfacial oxygen concentration. Further analysis of the electronic structure shows that no interface states are present at the O8 interface. These findings indicate that the O8 interface serves as a promising candidate for high quality III-V MOS devices. Moreover, interfacial states are present when such interfacial oxygen is partially removed. The interface states, leading to Fermi level pinning, originate from unsaturated interfacial Ga atoms.

Physical and electrical characterizations of AlGaN/GaN MOS gate stacks with AlGaN surface oxidation treatment

NASA Astrophysics Data System (ADS)

Yamada, Takahiro; Watanabe, Kenta; Nozaki, Mikito; Shih, Hong-An; Nakazawa, Satoshi; Anda, Yoshiharu; Ueda, Tetsuzo; Yoshigoe, Akitaka; Hosoi, Takuji; Shimura, Takayoshi; Watanabe, Heiji

2018-06-01

The impacts of inserting ultrathin oxides into insulator/AlGaN interfaces on their electrical properties were investigated to develop advanced AlGaN/GaN metal–oxide–semiconductor (MOS) gate stacks. For this purpose, the initial thermal oxidation of AlGaN surfaces in oxygen ambient was systematically studied by synchrotron radiation X-ray photoelectron spectroscopy (SR-XPS) and atomic force microscopy (AFM). Our physical characterizations revealed that, when compared with GaN surfaces, aluminum addition promotes the initial oxidation of AlGaN surfaces at temperatures of around 400 °C, followed by smaller grain growth above 850 °C. Electrical measurements of AlGaN/GaN MOS capacitors also showed that, although excessive oxidation treatment of AlGaN surfaces over around 700 °C has an adverse effect, interface passivation with the initial oxidation of the AlGaN surfaces at temperatures ranging from 400 to 500 °C was proven to be beneficial for fabricating high-quality AlGaN/GaN MOS gate stacks.

Three-Dimensional Visualization of Ozone Process Data.

DTIC Science & Technology

1997-06-18

Scattered Multivariate Data. IEEE Computer Graphics & Applications. 11 (May), 47-55. Odman, M.T. and Ingram, C.L. (1996) Multiscale Air Quality Simulation...the Multiscale Air Quality Simulation Platform (MAQSIP) modeling system. MAQSIP is a modular comprehensive air quality modeling system which MCNC...photolyzed back again to nitric oxide. Finally, oxides of 6 nitrogen are terminated through loss or combination into nitric acid, organic nitrates

Recent progress in high performance and reliable n-type transition metal oxide-based thin film transistors

NASA Astrophysics Data System (ADS)

Kwon, Jang Yeon; Kyeong Jeong, Jae

2015-02-01

This review gives an overview of the recent progress in vacuum-based n-type transition metal oxide (TMO) thin film transistors (TFTs). Several excellent review papers regarding metal oxide TFTs in terms of fundamental electron structure, device process and reliability have been published. In particular, the required field-effect mobility of TMO TFTs has been increasing rapidly to meet the demands of the ultra-high-resolution, large panel size and three dimensional visual effects as a megatrend of flat panel displays, such as liquid crystal displays, organic light emitting diodes and flexible displays. In this regard, the effects of the TMO composition on the performance of the resulting oxide TFTs has been reviewed, and classified into binary, ternary and quaternary composition systems. In addition, the new strategic approaches including zinc oxynitride materials, double channel structures, and composite structures have been proposed recently, and were not covered in detail in previous review papers. Special attention is given to the advanced device architecture of TMO TFTs, such as back-channel-etch and self-aligned coplanar structure, which is a key technology because of their advantages including low cost fabrication, high driving speed and unwanted visual artifact-free high quality imaging. The integration process and related issues, such as etching, post treatment, low ohmic contact and Cu interconnection, required for realizing these advanced architectures are also discussed.

Thermal and storage characteristics of tomato seed oil

USDA-ARS?s Scientific Manuscript database

Thermal oxidative stability and effect of different storage conditions on quality characteristics of tomato seed oil have not been studied. The objectives of this research were to determine the changes in quality and oxidative stability of tomato seed oil, including color, antioxidant activity, per...

Cobalt-doping-induced synthesis of ceria nanodisks and their significantly enhanced catalytic activity.

PubMed

Guo, Xiao-Hui; Mao, Chao-Chao; Zhang, Ji; Huang, Jun; Wang, Wa-Nv; Deng, Yong-Hui; Wang, Yao-Yu; Cao, Yong; Huang, Wei-Xin; Yu, Shu-Hong

2012-05-21

High-quality cobalt-doped ceria nanostructures with triangular column, triangular slab, and disklike shapes are synthesized by tuning the doping amount of cobalt nitrate in a facile hydrothermal reaction. The cobalt-doped ceria nanodisks display significantly enhanced catalytic activity in CO oxidation due to exposed highly active crystal planes and the presence of numerous surface defects. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Method for the production of cementitious compositions and aggregate derivatives from said compositions, and cementitious compositions and aggregates produced thereby

DOEpatents

Minnick, L. John

1983-01-01

The present invention relates to a method for preparing synthetic shaped cementitious compositions having high quality even without the addition of high energy binders, such as portland cement, through the use of the spent residue from a fluidized combustion bed of the type wherein limestone particles are suspended in a fluidized medium and sulfur oxides are captured, and pulverized coal fly ash.

Surface oxidation of GaN(0001): Nitrogen plasma-assisted cleaning for ultrahigh vacuum applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gangopadhyay, Subhashis; Schmidt, Thomas, E-mail: tschmidt@ifp.uni-bremen.de; Kruse, Carsten

The cleaning of metal-organic vapor-phase epitaxial GaN(0001) template layers grown on sapphire has been investigated. Different procedures, performed under ultrahigh vacuum conditions, including degassing and exposure to active nitrogen from a radio frequency nitrogen plasma source have been compared. For this purpose, x-ray photoelectron spectroscopy, reflection high-energy electron diffraction, and scanning tunneling microscopy have been employed in order to assess chemical as well as structural and morphological surface properties. Initial degassing at 600 °C under ultrahigh vacuum conditions only partially eliminates the surface contaminants. In contrast to plasma assisted nitrogen cleaning at temperatures as low as 300 °C, active-nitrogen exposure at temperaturesmore » as high as 700 °C removes the majority of oxide species from the surface. However, extended high-temperature active-nitrogen cleaning leads to severe surface roughening. Optimum results regarding both the removal of surface oxides as well as the surface structural and morphological quality have been achieved for a combination of initial low-temperature plasma-assisted cleaning, followed by a rapid nitrogen plasma-assisted cleaning at high temperature.« less

EBSD and TEM characterization of high burn-up mixed oxide fuel

NASA Astrophysics Data System (ADS)

Teague, Melissa; Gorman, Brian; Miller, Brandon; King, Jeffrey

2014-01-01

Understanding and studying the irradiation behavior of high burn-up oxide fuel is critical to licensing of future fast breeder reactors. Advancements in experimental techniques and equipment are allowing for new insights into previously irradiated samples. In this work dual column focused ion beam (FIB)/scanning electron microscope (SEM) was utilized to prepared transmission electron microscope samples from mixed oxide fuel with a burn-up of 6.7% FIMA. Utilizing the FIB/SEM for preparation resulted in samples with a dose rate of <0.5 mRem/h compared to ∼1.1 R/h for a traditionally prepared TEM sample. The TEM analysis showed that the sample taken from the cooler rim region of the fuel pellet had ∼2.5× higher dislocation density than that of the sample taken from the mid-radius due to the lower irradiation temperature of the rim. The dual column FIB/SEM was additionally used to prepared and serially slice ∼25 μm cubes. High quality electron back scatter diffraction (EBSD) were collected from the face at each step, showing, for the first time, the ability to obtain EBSD data from high activity irradiated fuel.

Structure and magnetic properties of FeSiAl-based soft magnetic composite with AlN and Al2O3 insulating layer prepared by selective nitridation and oxidation

NASA Astrophysics Data System (ADS)

Zhong, Xiaoxi; Liu, Ying; Li, Jun; Wang, Yiwei

2012-08-01

FeSiAl is widely used in switching power supply, filter inductors and pulse transformers. But when used under higher frequencies in some particular condition, it is required to reduce its high-frequency loss. Preparing a homogeneous insulating coating with good heat resistance and high resistivity, such as AlN and Al2O3, is supposed to be an effective way to reduce eddy current loss, which is less focused on. In this project, mixed AlN and Al2O3 insulating layers were prepared on the surface of FeSiAl powders after 30 min exposure at 1100 °C in high purity nitrogen atmosphere, by means of surface nitridation and oxidation. The results revealed that the insulating layers increase the electrical resistivity, and hence decrease the loss factor, improve the frequency stability and increase the quality factor, especially in the high-frequency range. The morphologies, microstructure and compositions of the oxidized and nitrided products on the surface were characterized by Scanning Electron Microscopy/Energy Disperse Spectroscopy, X-Ray Diffraction, Transmission Electron Microscopy, Selected Area Electron Diffraction and X-ray Photoelectron Spectroscopy.

EBSD and TEM Characterization of High Burn-up Mixed Oxide Fuel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Teague, Melissa C.; Gorman, Brian P.; Miller, Brandon D.

2014-01-01

Understanding and studying the irradiation behavior of high burn-up oxide fuel is critical to licensing of future fast breeder reactors. Advancements in experimental techniques and equipment are allowing for new insights into previously irradiated samples. In this work dual column focused ion beam (FIB)/scanning electron microscope (SEM) was utilized to prepared transmission electron microscope samples from mixed oxide fuel with a burn-up of 6.7% FIMA. Utilizing the FIB/SEM for preparation resulted in samples with a dose rate of <0.5 mRem/h compared to approximately 1.1 R/h for a traditionally prepared TEM sample. The TEM analysis showed that the sample taken frommore » the cooler rim region of the fuel pellet had approximately 2.5x higher dislocation density than that of the sample taken from the mid-radius due to the lower irradiation temperature of the rim. The dual column FIB/SEM was additionally used to prepared and serially slice approximately 25 um cubes. High quality electron back scatter diffraction (EBSD) were collected from the face at each step, showing, for the first time, the ability to obtain EBSD data from high activity irradiated fuel.« less

HfSe2 and ZrSe2: Two-dimensional semiconductors with native high-κ oxides

PubMed Central

Mleczko, Michal J.; Zhang, Chaofan; Lee, Hye Ryoung; Kuo, Hsueh-Hui; Magyari-Köpe, Blanka; Moore, Robert G.; Shen, Zhi-Xun; Fisher, Ian R.; Nishi, Yoshio; Pop, Eric

2017-01-01

The success of silicon as a dominant semiconductor technology has been enabled by its moderate band gap (1.1 eV), permitting low-voltage operation at reduced leakage current, and the existence of SiO2 as a high-quality “native” insulator. In contrast, other mainstream semiconductors lack stable oxides and must rely on deposited insulators, presenting numerous compatibility challenges. We demonstrate that layered two-dimensional (2D) semiconductors HfSe2 and ZrSe2 have band gaps of 0.9 to 1.2 eV (bulk to monolayer) and technologically desirable “high-κ” native dielectrics HfO2 and ZrO2, respectively. We use spectroscopic and computational studies to elucidate their electronic band structure and then fabricate air-stable transistors down to three-layer thickness with careful processing and dielectric encapsulation. Electronic measurements reveal promising performance (on/off ratio > 106; on current, ~30 μA/μm), with native oxides reducing the effects of interfacial traps. These are the first 2D materials to demonstrate technologically relevant properties of silicon, in addition to unique compatibility with high-κ dielectrics, and scaling benefits from their atomically thin nature. PMID:28819644

Oxidative damage to poultry: from farm to fork.

PubMed

Estévez, M

2015-06-01

Poultry and poultry meat are particularly susceptible to oxidative reactions. Oxidation processes have been for decades the focus of animal and meat scientists owing to the negative impact of these reactions on animal growth, performance, and food quality. Lipid oxidation has been recognized a major threat to the quality of processed poultry products. The recent discoveries on the occurrence of protein oxidation in muscle foods have increased the scientific and technological interest in a topic that broadens the horizons of food biochemistry into innovative fields. Furthermore, in recent years we have witnessed a growing interest in consumers on the impact of diet and oxidation on health and aging. Hence, the general description of oxidative reactions as harmful phenomena goes beyond the actual impact on animal production and food quality and reaches the potential influence of oxidized foods on consumer health. Likewise, the current antioxidant strategies aim for the protection of the living tissues, the food systems, and a potential health benefit in the consumer upon ingestion. Along these lines, the application of phytochemicals and other microelements (Se, Cu) with antioxidant potential in the feeds or directly in the meat product are strategies of substantial significance. The present paper reviews in a concise manner the most relevant and novel aspects of the mechanisms and consequences of oxidative reactions in poultry and poultry meat, and describes current antioxidant strategies against these undesirable reactions. © 2015 Poultry Science Association Inc.

Toxicity assessment of the water used for human consumption from the Cameron/Tuba City abandoned uranium mining area prior/after the combined electrochemical treatment/advanced oxidation.

PubMed

Gajski, Goran; Oreščanin, Višnja; Gerić, Marko; Kollar, Robert; Lovrenčić Mikelić, Ivanka; Garaj-Vrhovac, Vera

2015-01-01

The purpose of this work was detailed physicochemical, radiological, and toxicological characterization of the composite sample of water intended for human consumption in the Cameron/Tuba City abandoned uranium mining area before and after a combined electrochemical/advanced oxidation treatment. Toxicological characterization was conducted on human lymphocytes using a battery of bioassays. On the bases of the tested parameters, it could be concluded that water used for drinking from the tested water sources must be strictly forbidden for human and/or animal consumption since it is extremely cytogenotoxic, with high oxidative stress potential. A combined electrochemical treatment and posttreatment with ozone and UV light decreased the level of all physicochemical and radiological parameters below the regulated values. Consequently, the purified sample was neither cytotoxic nor genotoxic, indicating that the presented method could be used for the improvement of water quality from the sites highly contaminated with the mixture of heavy metals and radionuclides.

The in vitro effect of cypermethrin on quality and oxidative stress indices of rainbow trout Oncorhynchus mykiss spermatozoa.

PubMed

Kutluyer, Filiz; Benzer, Fulya; Erişir, Mine; Öğretmen, Fatih; İnanan, Burak Evren

2016-03-01

There is limited information on the scientific literature about the effect of in vitro exposure of fish sperm to pesticides. In vitro effect of cypermethrin on sperm quality and oxidative stress has not yet been fully investigated. Therefore, the effects of cypermethrin, a type II pyrethroid insecticide, on quality and oxidative stress of spermatozoa were examined in vitro. To explore the potential in vitro toxicity of cypermethrin, fish spermatozoa were incubated with different concentrations of cypermethrin (1.025, 2.05 and 4.1 μg/l) for 2 h. The motility rate and duration of sperm were determined after exposure to cypermethrin. Reduced glutathione (GSH), glutathione peroxidase (GSH-Px), catalase (CAT) and malondialdehyde (MDA) in spermatozoa were analyzed for determination of oxidant and antioxidant balance. Our results indicated that spermatozoa motility and duration significantly decreased with exposure to cypermethrin. Additionally, activity of GSH-Px (P<0.05) and MDA and GSH levels increased in a concentration-dependent manner while CAT activity decreased (P<0.05). Consequently, the oxidant and antioxidant status and sperm quality were affected by quantitative changes and different concentrations of cypermethrin. Copyright © 2015 Elsevier Inc. All rights reserved.

Ground Water Sampling at ISCO Sites - Residual Oxidant Impact on Sample Quality and Sample Preservation Guideline

EPA Science Inventory

In-situ chemical oxidation (ISCO) involves the delivery of a chemical oxidant into the subsurface where oxidative reactions transform ground water contaminants into less toxic or harmless byproducts. Due to oxidant persistence, ground water samples collected at hazardous waste si...

Effect of microwave heating on the quality characteristics of canola oil in presence of palm olein.

PubMed

Ali, M Abbas; Nouruddeen, Zahrau Bamalli; Muhamad, Ida Idayu; Latip, Razam Abd; Othman, Noor Hidayu

2013-01-01

Microwave heating is one of the most attractive cooking methods for food preparation, commonly employed in households and especially in restaurants for its high speed and convenience. The chemical constituents of oils that degrade during microwave heating do so at rates that vary with heating temperature and time in a similar manner to other type of processing methods. The rate of quality characteristics of the oil depends on the fatty acid composition and the minor components during heating. Addition of oxidative-stable palm olein (PO) to heat sensitive canola oil (CO), may affect the quality characteristics of CO during microwave heating. The aim of this study was to evaluate how heat treatments by microwave oven affect the quality of CO in presence of PO. The blend was prepared in the volume ratio of 40:60 (PO:CO, PC). Microwave heating test was performed for different periods (2, 4, 8, 12, 16 and 20 min) at medium power setting for the samples of CO and PC. The changes in quality characteristics of the samples during heating were determined by analytical and instrumental methods. In this study, refractive index, free fatty acid content, peroxide value, p-anisidine value, TOTOX value, specific extinction, viscosity, polymer content, polar compounds and food oil sensor value of the oils all increased, whereas iodine value and C₁₈.₂ /C₁₆:₀ ratio decreased as microwave heating progressed. Based on the most oxidative stability criteria, PO addition led to a slower deterioration of CO at heating temperatures. The effect of microwave heating on the fatty acid composition of the samples was not remarkable. PO addition decelerated the formation of primary and secondary oxidation products in CO. However, effect of adding PO to CO on the formation of free fatty acids and polymers during microwave treatment was not significant (P < 0.05). No significant difference in food oil sensor value was detected between CO and PC throughout the heating periods. Microwave heating caused formation of comparatively lower amounts of some degradative products in PC compared to CO indicating a lower extent of oxidative degradation of PC.

Direct-write maskless lithography using patterned oxidation of Si-substrate Induced by femtosecond laser pulses

NASA Astrophysics Data System (ADS)

Kiani, Amirkianoosh; Venkatakrishnan, Krishnan; Tan, Bo

2013-03-01

In this study we report a new method for direct-write maskless lithography using oxidized silicon layer induced by high repetition (MHz) ultrafast (femtosecond) laser pulses under ambient condition. The induced thin layer of predetermined pattern can act as an etch stop during etching process in alkaline etchants such as KOH. The proposed method can be leading to promising solutions for direct-write maskless lithography technique since the proposed method offers a higher degree of flexibility and reduced time and cost of fabrication which makes it particularly appropriate for rapid prototyping and custom scale manufacturing. A Scanning Electron Microscope (SEM), Micro-Raman, Energy Dispersive X-ray (EDX), optical microscope and X-ray diffraction spectroscopy (XRD) were used to evaluate the quality of oxidized layer induced by laser pulses.

Nanopatterning of Crystalline Silicon Using Anodized Aluminum Oxide Templates for Photovoltaics

NASA Astrophysics Data System (ADS)

Chao, Tsu-An

A novel thin film anodized aluminum oxide templating process was developed and applied to make nanopatterns on crystalline silicon to enhance the optical properties of silicon. The thin film anodized aluminum oxide was created to improve the conventional thick aluminum templating method with the aim for potential large scale fabrication. A unique two-step anodizing method was introduced to create high quality nanopatterns and it was demonstrated that this process is superior over the original one-step approach. Optical characterization of the nanopatterned silicon showed up to 10% reduction in reflection in the short wavelength range. Scanning electron microscopy was also used to analyze the nanopatterned surface structure and it was found that interpore spacing and pore density can be tuned by changing the anodizing potential.

Surface Selective Oxide Reduction During the Intercritical Annealing of Medium Mn Steel

NASA Astrophysics Data System (ADS)

Jo, Kyoung Rae; Cho, Lawrence; Oh, Jong Han; Kim, Myoung Soo; Kang, Ki Cheol; De Cooman, Bruno C.

2017-08-01

Third generation advanced high-strength steels achieve an excellent strength-ductility balance using a cost-effective alloy composition. During the continuous annealing of medium Mn steel, the formation of an external selective oxide layer of MnO has a negative impact on the coating quality after galvanizing. A procedure to reduce the selective oxide was therefore developed. It involves annealing in the temperature range of 1073 K to 1323 K (800 °C to 1050 °C) in a HNx gas atmosphere. Annealing at higher temperatures and the use of larger H2 volume fractions are shown to make the gas atmosphere reducing with respect to MnO. The reduction of the surface MnO layer was observed by SEM, GDOES, and cross-sectional TEM analysis.

Coaxial metal-oxide-semiconductor (MOS) Au/Ga2O3/GaN nanowires.

PubMed

Hsieh, Chin-Hua; Chang, Mu-Tung; Chien, Yu-Jen; Chou, Li-Jen; Chen, Lih-Juann; Chen, Chii-Dong

2008-10-01

Coaxial metal-oxide-semiconductor (MOS) Au-Ga2O3-GaN heterostructure nanowires were successfully fabricated by an in situ two-step process. The Au-Ga2O3 core-shell nanowires were first synthesized by the reaction of Ga powder, a mediated Au thin layer, and a SiO2 substrate at 800 degrees C. Subsequently, these core-shell nanowires were nitridized in ambient ammonia to form a GaN coating layer at 600 degrees C. The GaN shell is a single crystal, an atomic flat interface between the oxide and semiconductor that ensures that the high quality of the MOS device is achieved. These novel 1D nitride-based MOS nanowires may have promise as building blocks to the future nitride-based vertical nanodevices.

Laser method for forming low-resistance ohmic contacts on semiconducting oxides

DOEpatents

Narayan, Jagdish

1981-01-01

This invention is a new method for the formation of high-quality ohmic contacts on wide-band-gap semiconducting oxides. As exemplified by the formation of an ohmic contact on n-type BaTiO.sub.3 containing a p-n junction, the invention entails depositing a film of a metallic electroding material on the BaTiO.sub.3 surface and irradiating the film with a Q-switched laser pulse effecting complete melting of the film and localized melting of the surface layer of oxide immediately underlying the film. The resulting solidified metallic contact is ohmic, has unusually low contact resistance, and is thermally stable, even at elevated temperatures. The contact does not require cleaning before attachment of any suitable electrical lead. This method is safe, rapid, reproducible, and relatively inexpensive.

Method for forming low-resistance ohmic contacts on semiconducting oxides

DOEpatents

Narayan, J.

1979-10-01

The invention provides a new method for the formation of high-quality ohmic contacts on wide-band-gap semiconducting oxides. As exemplified by the formation of an ohmic contact on n-type BaTiO/sub 3/ containing a p-n junction, the invention entails depositing a film of a metallic electroding material on the BaTiO/sub 3/ surface and irradiating the film with a Q-switched laser pulse effecting complete melting of the film and localized melting of the surface layer of oxide immediately underlying the film. The resulting solidified metallic contact is ohmic, has unusually low contact resistance, and is thermally stable, even at elevated temmperatures. The contact does not require cleaning before attachment of any suitable electrical lead. This method is safe, rapid, reproducible, and relatively inexpensive.

Moisture barrier properties of single-layer graphene deposited on Cu films for Cu metallization

NASA Astrophysics Data System (ADS)

Gomasang, Ploybussara; Abe, Takumi; Kawahara, Kenji; Wasai, Yoko; Nabatova-Gabain, Nataliya; Thanh Cuong, Nguyen; Ago, Hiroki; Okada, Susumu; Ueno, Kazuyoshi

2018-04-01

The moisture barrier properties of large-grain single-layer graphene (SLG) deposited on a Cu(111)/sapphire substrate are demonstrated by comparing with the bare Cu(111) surface under an accelerated degradation test (ADT) at 85 °C and 85% relative humidity (RH) for various durations. The change in surface color and the formation of Cu oxide are investigated by optical microscopy (OM) and X-ray photoelectron spectroscopy (XPS), respectively. First-principle simulation is performed to understand the mechanisms underlying the barrier properties of SLG against O diffusion. The correlation between Cu oxide thickness and SLG quality are also analyzed by spectroscopic ellipsometry (SE) measured on a non-uniform SLG film. SLG with large grains shows high performance in preventing the Cu oxidation due to moisture during ADT.

Study of bulk Hafnium oxide (HfO2) under compression

NASA Astrophysics Data System (ADS)

Pathak, Santanu; Mandal, Guruprasad; Das, Parnika

2018-04-01

Hafnium oxide (HfO2) is a technologically important material. This material has K-value of 25 and band gap 5.8 eV. A k value of 25-30 is preferred for a gate dielectric [1]. As it shows good insulating and capacitive properties, HfO2 is being considered as a replacement to SiO2 in microelectronic devices as gate dielectrics. On the other hand because of toughening mechanism due to phase transformation induced by stress field observed in these oxides, HFO2 has been a material of investigations in various configurations for a very long time. However the controversies about phase transition of HfO2 under pressure still exists. High quality synchrotron radiation has been used to study the structural phase transition of HfO2 under pressure.

Single-crystal-like, c-axis oriented BaTiO3 thin films with high-performance on flexible metal templates for ferroelectric applications

NASA Astrophysics Data System (ADS)

Shin, Junsoo; Goyal, Amit; Jesse, Stephen; Kim, Dae Ho

2009-06-01

Epitaxial, c-axis oriented BaTiO3 thin films were deposited using pulsed laser ablation on flexible, polycrystalline Ni alloy tape with biaxially textured oxide buffer multilayers. The high quality of epitaxial BaTiO3 thin films with P4mm group symmetry was confirmed by x-ray diffraction. The microscopic ferroelectric domain structure and the piezoelectric domain switching in these films were confirmed via spatially resolved piezoresponse mapping and local hysteresis loops. Macroscopic measurements demonstrate that the films have well-saturated hysteresis loops with a high remanent polarization of ˜11.5 μC/cm2. Such high-quality, single-crystal-like BaTiO3 films on low-cost, polycrystalline, flexible Ni alloy substrates are attractive for applications in flexible lead-free ferroelectric devices.

Agarose Gel Electrophoresis System in the Classroom: Detection of DNA Strand Breaks through the Alteration of Plasmid Topology

ERIC Educational Resources Information Center

De Mattos, J. C. P.; Dantas, F. J. S.; Caldeira-de-Araujo, A.; Moraes, M. O.

2004-01-01

Good quality scientific teaching depends on the ability of researchers to translate laboratory experiments into high school and undergraduate classes, bridging the advanced and basic science with common knowledge. A fast-growing field in biomedical sciences is oxidative stress, which has been associated to several diseases, including cancer and…

ENVIRONMENTAL TECHNOLOGY VERIFICATION--TEST REPORT OF MOBILE SOURCE EMISSION CONTROL DEVICES, CUMMINS EMISSION SOLUTIONS AND CUMMINS FILTRATION DIESEL OXIDATION CATALYST AND CLOSED CRANKCASE VENTILATION SYSTEM

EPA Science Inventory

The U.S. EPA has created the Environmental Technology Verification (ETV) Program. ETV seeks to provide high-quality, peer-reviewed data on technology performance. The Air Pollution Control Technology (APCT) Verification Center, a center under the ETV Program, is operated by Res...

Precision lens molding of asphero diffractive surfaces in chalcogenide materials

NASA Astrophysics Data System (ADS)

Nelson, J.; Scordato, M.; Schwertz, K.; Bagwell, J.

2015-10-01

Finished lens molding, and the similar process of precision lens molding, have long been practiced for high volume, accurate replication of optical surfaces on oxide glass. The physics surrounding these processes are well understood, and the processes are capable of producing high quality optics with great fidelity. However, several limitations exist due to properties inherent with oxide glasses. Tooling materials that can withstand the severe environmental conditions of oxide glass molding cannot easily be machined to produce complex geometries such as diffractive surfaces, lens arrays, and off axis features. Current machining technologies coupled with a limited selection of tool materials greatly limits the type of structures that can be molded into the finished optic. Tooling for chalcogenide glasses are not bound by these restrictions since the molding temperatures required are much lower than for oxide glasses. Innovations in tooling materials and manufacturing techniques have enabled the production of complex geometries to optical quality specifications and have demonstrated the viability of creating tools for molding diffractive surfaces, off axis features, datums, and arrays. Applications for optics having these features are found in automotive, defense, security, medical, and industrial domains. This paper will discuss results achieved in the study of various molding techniques for the formation of positive diffractive features on a concave spherical surface molded from As2Se3 chalcogenide glass. Examples and results of molding with tools having CTE match with the glass and non CTE match will be reviewed. The formation of stress within the glass during molding will be discussed, and methods of stress management will also be demonstrated and discussed. Results of process development methods and production of good diffractive surfaces will be shown.

Isoprene and its degradation products as strong ozone precursors in Insubria, Northern Italy

NASA Astrophysics Data System (ADS)

Duane, M.; Poma, B.; Rembges, D.; Astorga, C.; Larsen, B. R.

Frequent smog episodes occur during spring, summer, and autumn in Insubria, Northern Italy. On a test site in this area the atmospheric concentration of the photo-oxidants ozone and peroxyacetyl nitrate has been monitored over a year (2000) together with ozone precursors listed in the European Union Air Quality Directive 2002/3/EC, such as nitrous oxides (NO X) and volatile organic compounds (VOC) including hydrocarbons and carbonyls. The results of this study revealed a strong impact of biogenic isoprene on the air quality. In winter isoprene was detected at the ppt level and correlated with anthropogenic VOC. However, during the growing season isoprene exhibited a distinct diurnal variation with maximum concentrations late in the afternoon reaching up 70 ppbC attributed to strong emissions from the abundant vegetation of broad-leaf deciduous trees in this area. A new HPLC-MS method was developed for the determination of isoprene's primary atmospheric oxidation products methacrolein as its 2,4-dinitrophenylhydrazone and methyl vinyl ketone as an unusual double derivative with 2,4-dinitrophenylhydrazine. Methacrolein and methyl vinyl ketone followed the same diurnal and annual trends as isoprene. The average monthly concentration of isoprene and these products ranged from around 10 ppbC in June, July and September to 20 ppbC in August, which constitutes 15-30% of C 3-C 9 VOCs. The contribution from isoprene photo-oxidation to the ambient air formaldehyde concentrations was also found to be high during this period ranging from 30% to 60% in May, June, July and August. From the atmospheric VOC and NO X concentrations the local photochemical ozone formation was estimated by the incremental reactivity approach. The calculations showed that in summer isoprene's contribution to the local ozone formation was as high as 50-75%.

Recovery of iron oxides from acid mine drainage and their application as adsorbent or catalyst.

PubMed

Flores, Rubia Gomes; Andersen, Silvia Layara Floriani; Maia, Leonardo Kenji Komay; José, Humberto Jorge; Moreira, Regina de Fatima Peralta Muniz

2012-11-30

Iron oxide particles recovered from acid mine drainage represent a potential low-cost feedstock to replace reagent-grade chemicals in the production of goethite, ferrihydrite or magnetite with relatively high purity. Also, the properties of iron oxides recovered from acid mine drainage mean that they can be exploited as catalysts and/or adsorbents to remove azo dyes from aqueous solutions. The main aim of this study was to recover iron oxides with relatively high purity from acid mine drainage to act as a catalyst in the oxidation of dye through a Fenton-like mechanism or as an adsorbent to remove dyes from an aqueous solution. Iron oxides (goethite) were recovered from acid mine drainage through a sequential precipitation method. Thermal treatment at temperatures higher than 300 °C produces hematite through a decrease in the BET area and an increase in the point of zero charge. In the absence of hydrogen peroxide, the solids adsorbed the textile dye Procion Red H-E7B according to the Langmuir model, and the maximum amount adsorbed decreased as the temperature of the thermal treatment increased. The decomposition kinetics of hydrogen peroxide is dependent on the H(2)O(2) concentration and iron oxides dosage, but the second-order rate constant normalized to the BET surface area is similar to that for different iron oxides tested in this and others studies. These results indicate that acid mine drainage could be used as a source material for the production of iron oxide catalysts/adsorbents, with comparable quality to those produced using analytical-grade reagents. Copyright © 2012 Elsevier Ltd. All rights reserved.

Water Quality Analysis of Yosemite Creek Watershed, San Francisco, California

NASA Astrophysics Data System (ADS)

Davis, J. R.; Snow, M. K.; Aquino, A.; Huang, C.; Thai, A.; Yuen, C.

2003-12-01

Surface water quality in urban settings can become contaminated by anthropogenic inputs. Yosemite Creek watershed is situated on the east side of San Francisco near Bayview Hunters Point and provides an ideal location for water quality investigations in urban environments. Accordingly, students from Philip and Sala Burton High School monitored water quality at three locations for their physicochemical and biological characteristics. Water was tested for pH, dissolved oxygen, conductivity, total dissolved solids, salinity, and oxidation reduction potential. In addition, a Hach DR 850 digital colorimeter was utilized to measure chlorine, fluorine, nitrogen, phosphorous, and sulfate. The biological component was assessed via monitoring benthic macro invertebrates. Specifically, the presence of caddisfly (Trichoptera) were used to indicate low levels of contaminants and good water quality. Our results indicate that water quality and macro invertebrate populations varied spatially within the watershed. Further investigation is needed to pinpoint the precise location of contaminant inputs.

Evaluating Multipollutant Exposure and Urban Air Quality: Pollutant Interrelationships, Neighborhood Variability, and Nitrogen Dioxide as a Proxy Pollutant

PubMed Central

Levy, Ilan; Mihele, Cristian; Lu, Gang; Narayan, Julie; Brook, Jeffrey R.

2013-01-01

Background: Although urban air pollution is a complex mix containing multiple constituents, studies of the health effects of long-term exposure often focus on a single pollutant as a proxy for the entire mixture. A better understanding of the component pollutant concentrations and interrelationships would be useful in epidemiological studies that exploit spatial differences in exposure by clarifying the extent to which measures of individual pollutants, particularly nitrogen dioxide (NO2), represent spatial patterns in the multipollutant mixture. Objectives: We examined air pollutant concentrations and interrelationships at the intraurban scale to obtain insight into the nature of the urban mixture of air pollutants. Methods: Mobile measurements of 23 air pollutants were taken systematically at high resolution in Montreal, Quebec, Canada, over 34 days in the winter, summer, and autumn of 2009. Results: We observed variability in pollution levels and in the statistical correlations between different pollutants according to season and neighborhood. Nitrogen oxide species (nitric oxide, NO2, nitrogen oxides, and total oxidized nitrogen species) had the highest overall spatial correlations with the suite of pollutants measured. Ultrafine particles and hydrocarbon-like organic aerosol concentration, a derived measure used as a specific indicator of traffic particles, also had very high correlations. Conclusions: Our findings indicate that the multipollutant mix varies considerably throughout the city, both in time and in space, and thus, no single pollutant would be a perfect proxy measure for the entire mix under all circumstances. However, based on overall average spatial correlations with the suite of pollutants measured, nitrogen oxide species appeared to be the best available indicators of spatial variation in exposure to the outdoor urban air pollutant mixture. Citation: Levy I, Mihele C, Lu G, Narayan J, Brook JR. 2014. Evaluating multipollutant exposure and urban air quality: pollutant interrelationships, neighborhood variability, and nitrogen dioxide as a proxy pollutant. Environ Health Perspect 122:65–72; http://dx.doi.org/10.1289/ehp.1306518 PMID:24225648

The addition of pineapple flesh and pineapple peels extracts to increase the quality of used cooking oil

NASA Astrophysics Data System (ADS)

Kusumawardani, R.; Hasanah, N.; Sukemi

2018-04-01

In Indonesia, reuse of cooking oil is high and common. Heating process and reuse of the cooking oil causes a change in its chemical constituents and decrease its qualities. This research aimed to investigate the addition of pineapple flesh extract (PFE) and pineapple peel extract (PPE) on the increment of the quality of oxidized (used) cooking oil. The cooking oil has been used three times. Treatment was done by mixing the used cooking oil with the extract (2:1) at 50°C. Peroxide value, FFA and iodine number of treated and untreated used cooking oils were measured by using titration method. The result showed that the treatment could increase the quality of the used cooking oils. PPE was better than PFE to increase the quality of the used cooking oil.

Determining Changes in Groundwater Quality during Managed Aquifer Recharge

NASA Astrophysics Data System (ADS)

Gambhir, T.; Houlihan, M.; Fakhreddine, S.; Dadakis, J.; Fendorf, S. E.

2016-12-01

Managed aquifer recharge (MAR) is becoming an increasingly prevalent technology for improving the sustainability of freshwater supply. However, recharge water can alter the geochemical conditions of the aquifer, mobilizing contaminants native to the aquifer sediments. Geochemical alterations on deep (>300 m) injection of highly treated recycled wastewater for MAR has received limited attention. We aim to determine how residual disinfectants used in water treatment processes, specifically the strong oxidants chloramine and hydrogen peroxide, affect metal mobilization within deep injection wells of the Orange County Water District. Furthermore, as the treated recharge water has very low ionic strength (44.6 mg L-1 total dissolved solids), we tested how differing concentrations of magnesium chloride and calcium chloride affected metal mobilization within deep aquifers. Continuous flow experiments were conducted on columns dry packed with sediments from a deep injection MAR site in Orange County, CA. The effluent was analyzed for shifts in water quality, including aqueous concentrations of arsenic, uranium, and chromium. Interaction between the sediment and oxic recharge solution causes naturally-occurring arsenopyrite to repartition onto iron oxides. The stability of arsenic on the newly precipitated iron oxides is dependent on pH changes during recharge.

Study of thickness and uniformity of oxide passivation with DI-O3 on silicon substrate for electronic and photonic applications

NASA Astrophysics Data System (ADS)

Sharma, Mamta; Hazra, Purnima; Singh, Satyendra Kumar

2018-05-01

Since the beginning of semiconductor fabrication technology evolution, clean and passivated substrate surface is one of the prime requirements for fabrication of Electronic and optoelectronic device fabrication. However, as the scale of silicon circuits and device architectures are continuously decreased from micrometer to nanometer (from VLSI to ULSI technology), the cleaning methods to achieve better wafer surface qualities has raised research interests. The development of controlled and uniform silicon dioxide is the most effective and reliable way to achieve better wafer surface quality for fabrication of electronic devices. On the other hand, in order to meet the requirement of high environment safety/regulatory standards, the innovation of cleaning technology is also in demand. The controlled silicon dioxide layer formed by oxidant de-ionized ozonated water has better uniformity. As the uniformity of the controlled silicon dioxide layer is improved on the substrate, it enhances the performance of the devices. We can increase the thickness of oxide layer, by increasing the ozone time treatment. We reported first time to measurement of thickness of controlled silicon dioxide layer and obtained the uniform layer for same ozone time.

The in vitro effect of nonylphenol, propranolol, and diethylstilbestrol on quality parameters and oxidative stress in sterlet (Acipenser ruthenus) spermatozoa.

PubMed

Shaliutina, Olena; Shaliutina-Kolešová, Anna; Lebeda, Ievgen; Rodina, Marek; Gazo, Ievgeniia

2017-09-01

The sturgeon is a highly endangered fish mostly due to over-fishing, habitat destruction, and water pollution. Nonylphenol (NP), propranolol (PN), and diethylstilbestrol (DES) are multifunctional xenobiotic compounds used in a variety of commercial and industrial products. The mechanism by which these xenobiotic compounds interfere with fish reproduction is not fully elucidated. This study assessed the effect of NP, PN, and DES on motility parameters, membrane integrity, and oxidative/antioxidant status in sterlet Acispenser ruthenus spermatozoa. Spermatozoa were incubated with several concentrations of target substances for 1h. Motility rate and velocity of spermatozoa decreased in the presence of xenobiotics in a dose-dependent manner compared with controls. A significant decrease in membrane integrity was recorded with exposure to 5μM of NP, 25μM of PN, and 50μM of DES. After 1h exposure at higher tested concentrations NP (5-25μM), PN (25-100μM), and DES (50-200μM), oxidative stress was apparent, as reflected by significantly higher levels of protein and lipid oxidation and significantly greater superoxide dismutase activity. The results demonstrated that NP, PN, and DES can induce reactive oxygen species stress in fish spermatozoa, which could impair sperm quality and the antioxidant defence system and decrease the percentage of intact sperm cells. Copyright © 2017 Elsevier Ltd. All rights reserved.

Air Quality Criteria for Ozone and Related Photochemical Oxidants (First External Review Draft)

EPA Science Inventory

This first external review draft of the Air Quality Criteria for Ozone and Related Photochemical Oxidants (Ozone Criteria Document) is being released in January 2005 for public comment and for review by EPA's Clean A...

Air Quality Criteria for Ozone and Related Photochemical Oxidants (Second External Review Draft)

EPA Science Inventory

This second external review draft of the Air Quality Criteria for Ozone and Related Photochemical Oxidants, Volumes I-III (Ozone Criteria Document) is being released for public comment and for review by EPA's Clean Air Scientific Advisory Committee (CASAC) r...

A first-approximation urban-air-quality indicator

Treesearch

David M. Paproski; Julian R. Walker

1977-01-01

Development of the first-approximation-urban-air-quality indicator was reported by the Economic Council of Canada. The indicator takes account of ambient concentrations of five pollutants: sulfur dioxide, particulate matter, oxides of nitrogen, carbon monoxide, and total oxidants. Epidemiological evidence indicating the potential impact of these pollutants on human...

Air Quality Criteria for Particulate Matter and Sulfur Oxides (Final Report, 1982)

EPA Science Inventory

Particulate matter and sulfur oxides are two of six major air pollutants regulated by National Ambient Air Quality Standards (NAAQS) under the U.S. Clean Air Act. As mandated by the Clean Air Act, the U.S. Environmental Protection Agency (EPA) must periodically review the scienti...

Nano-sized particles, processes of making, compositions and uses thereof

DOEpatents

O'Brien, Stephen [New York, NY; Yin, Ming [Los Alamos, NM

2012-05-22

The present invention describes methods for preparing high quality nanoparticles, i.e., metal oxide based nanoparticles of uniform size and monodispersity. The nanoparticles advantageously comprise organic alkyl chain capping groups and are stable in air and in nonpolar solvents. The methods of the invention provide a simple and reproducible procedure for forming transition metal oxide nanocrystals, with yields over 80%. The highly crystalline and monodisperse nanocrystals are obtained directly without further size selection; particle size can be easily and fractionally increased by the methods. The resulting nanoparticles can exhibit magnetic and/or optical properties. These properties result from the methods used to prepare them. Also advantageously, the nanoparticles of this invention are well suited for use in a variety of industrial applications, including cosmetic and pharmaceutical formulations and compositions.

Updated model assessment of pollution at major U. S. Airports

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yamartino, R.J.; Rote, D.M.

1979-02-01

The air quality impact of aircraft at and around Los Angeles International Airport (LAX) is simulated for hours of peak aircraft operation and worst case pollutant dispersion conditions. An updated version of the Argonne Airport Vicinity Air Pollution (AVAP) model is used in the simulation; model refinements reflect new theoretical formulations and data from field programs at LAX, O'Hare, and John F. Kennedy International Airports. Maximum carbon monoxide concentrations at LAX are found to be low relative to the NAAQS. Relatively high, widespread hydrocarbon levels indicate that aircraft emissions may aggravate oxidant problems near the airport. Concentrations of oxides ofmore » nitrogen are high enough relative to proposed standards to warrant further study. Similar modeling is underway for the O'Hare and JFK airports.« less

Potential oil yield, fatty acid composition, and oxidation stability of the hempseed oil from four Cannabis sativa L. cultivars.

PubMed

Da Porto, Carla; Decorti, Deborah; Natolino, Andrea

2015-03-01

The cultivation of four industrial hemp cultivars (Felina 32, Chamaeleon, Uso31, and Finola) was investigated for oil production in the north-east of Italy along two years. The oils of all cultivars resulted in rich amount of linoleic acid (ω-6) and α-linolenic acid (ω-3). Felina 32 and Chamaeleon oils exhibited the highest amount of linoleic acid (59%) and α-linolenic acid (18%). Finola and Uso31 oils resulted in the richest of γ-linolenic acid (5-6%). All hempseed oils presented high oxidation stability and an acceptable initial quality. It is suggested that these oils can be used to produce EFA dietary supplements high in ω-6 and ω-3 of vegetal origin.

High Throughput Detection of Tetracycline Residues in Milk Using Graphene or Graphene Oxide as MALDI-TOF MS Matrix

NASA Astrophysics Data System (ADS)

Liu, Junyan; Liu, Yang; Gao, Mingxia; Zhang, Xiangmin

2012-08-01

In this work, a new pre-analysis method for tetracyclines (TCs) detection from the milk samples was established. As a good accomplishment for the existing accurate quantification strategies for TCs detection, the new pre-analysis method was demonstrated to be simple, sensitive, fast, cost effective, and high throughput, which would do a great favor to the routine quality pre-analysis of TCs from milk samples. Graphene or graphene oxide was utilized, for the first time, as a duel-platform to enrich and detect the TCs by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). All together, four TCs were chosen as models: tetracycline, oxytetracycline, demeclocycline, and chlortetracycline. Due to the excellent electronic, thermal, and mechanical properties, graphene and graphene oxide were successfully applied as matrices for MALDI-TOF MS with free background inference in low mass range. Meanwhile, graphene or graphene oxide has a large surface area and strong interaction force with the analytes. By taking the advantage of these features, TCs were effectively enriched with the limit of detection (LOD) as low as 2 nM.

Final report for project "Next-Generation Semiconductors for Solar Photoelectrolysis"

DOE Office of Scientific and Technical Information (OSTI.GOV)

Khalifah, Peter

2016-09-15

In this paper, effective methods have been developed for preparing high-quality LaTiO 2N films on conductive La 5Ti 5O 17 substrates that can serve as photoanodes for photoelectrochemical water oxidation. One paper has been written by the post-doc who completed this comprehensive, interdisciplinary study, and it is presently being finalized for submission. Our approach to this system integrates expertise that we have developed in single crystal growth, thin film growth, and thin film post-processing. Through this work, LTON films have been fully optimized for light harvesting, as their band gap is optimally matched with the incident solar spectrum and themore » film thicknesses have been optimized based on the absolute absorption coefficients that we have measured for this system. The next step is to optimize the co-catalyst functionalization and the solution conditions to maximize the catalytic activity for water oxidation. Since the preliminary tests described here were done without a water oxidation co-catalyst, and since good water oxidation catalysts have previously been identified based on studies of powder samples, this next step is highly likely to be successful.« less

Self-assembled Co-BaZrO 3 nanocomposite thin films with ultra-fine vertically aligned Co nanopillars

DOE PAGES

Huang, Jijie; Li, Leigang; Lu, Ping; ...

2017-05-11

A simple one-step pulsed laser deposition (PLD) method has been applied to grow self-assembled metal-oxide nanocomposite thin films. The as-deposited Co-BaZrO 3 films show high epitaxial quality with ultra-fine vertically aligned Co nanopillars (diameter <5 nm) embeded in BZO matrix. The diameter of the nanopillars can be further tuned by varying the deposition frequency. The metal and oxide phases grow separately without inter-diffusion or mixing. Taking advantage of this unique structure, a high saturation magnetization of ~1375 emu/cm 3 in the Co- BaZrO 3 nanocomposites has been achieved and further confirmed by Lorentz microscopy imaging in TEM. Furthermore, the coercivitymore » values of this nanocomposite thin films range from 600 Oe (20 Hz) to 1020 Oe (2 Hz), which makes the nanocomposite an ideal candidate for high-density perpendicular recording media.« less

Graphene-based smart materials

NASA Astrophysics Data System (ADS)

Yu, Xiaowen; Cheng, Huhu; Zhang, Miao; Zhao, Yang; Qu, Liangti; Shi, Gaoquan

2017-09-01

The high specific surface area and the excellent mechanical, electrical, optical and thermal properties of graphene make it an attractive component for high-performance stimuli-responsive or 'smart' materials. Complementary to these inherent properties, functionalization or hybridization can substantially improve the performance of these materials. Typical graphene-based smart materials include mechanically exfoliated perfect graphene, chemical vapour deposited high-quality graphene, chemically modified graphene (for example, graphene oxide and reduced graphene oxide) and their macroscopic assemblies or composites. These materials are sensitive to a range of stimuli, including gas molecules or biomolecules, pH value, mechanical strain, electrical field, and thermal or optical excitation. In this Review, we outline different graphene-based smart materials and their potential applications in actuators, chemical or strain sensors, self-healing materials, photothermal therapy and controlled drug delivery. We also introduce the working mechanisms of graphene-based smart materials and discuss the challenges facing the realization of their practical applications.

Fabrication and Performance Study on Individual Zno Nanowires Based Bioelectrode

NASA Astrophysics Data System (ADS)

Zhao, Yanguang; Yan, Xiaoqin; Kang, Zhuo; Lin, Pei

2012-08-01

One-dimensional zinc oxide nanowires (ZnO NWs) have unique advantages for use in biosensors as follows: oxide stable surface, excellent biosafety, high specific surface area, high isoelectric point (IEP = 9.5). In this work, we have prepared a kind of electrochemical bioelectrode based on individual ZnO NWs. Here, ZnO NWs with high quality were successfully synthesized by CVD method, which were characterized by scanning electron microscopy, X-ray diffraction and photoluminescence. Then the Raman spectra and electrical characterization demonstrated the adsorption of uricase on ZnO wires. At last, a series of electrochemical measurements were carried out by using an electrochemical workstation with a conventional three-electrode system to obtain the cyclic voltammetry characteristics of the bioelectrodes. The excellent performance of the fabricated bioelectrode implies the potential application for single ZnO nanowire to construct electrochemical biosensor for the detection of uric acid.

Strain-induced oxygen vacancies in ultrathin epitaxial CaMnO3 films

NASA Astrophysics Data System (ADS)

Chandrasena, Ravini; Yang, Weibing; Lei, Qingyu; Delgado-Jaime, Mario; de Groot, Frank; Arenholz, Elke; Kobayashi, Keisuke; Aschauer, Ulrich; Spaldin, Nicola; Xi, Xiaoxing; Gray, Alexander

Dynamic control of strain-induced ionic defects in transition-metal oxides is considered to be an exciting new avenue towards creating materials with novel electronic, magnetic and structural properties. Here we use atomic layer-by-layer laser molecular beam epitaxy to synthesize high-quality ultrathin single-crystalline CaMnO3 films with systematically varying coherent tensile strain. We then utilize a combination of high-resolution soft x-ray absorption spectroscopy and bulk-sensitive hard x-ray photoemission spectroscopy in conjunction with first-principles theory and core-hole multiplet calculations to establish a direct link between the coherent in-plane strain and the oxygen-vacancy content. We show that the oxygen vacancies are highly mobile, which necessitates an in-situ-grown capping layer in order to preserve the original strain-induced oxygen-vacancy content. Our findings open the door for designing and controlling new ionically active properties in strongly-correlated transition-metal oxides.

Development of F.T. Raman Spectroscopy

DTIC Science & Technology

1989-06-19

vibrations of. the OHO group. The work nears completion. ’a have examined a range of tellurium organometallics and their z_-plexes. The high quality of-the...chemistry. High oxidation states of Mo, VIv, MnVI. Curi , Fe r r’ and several others have been identified as problematic since absorption of the laser...polymers is in hand. In these, spectral charges through and above the melting point are of interest. Several fibre systems have been studied including

The preparation of high quality alumina defective photonic crystals and their application of photoluminescence enhancement

NASA Astrophysics Data System (ADS)

An, Yu-Ying; Wang, Jian; Zhou, Wen-Ming; Jin, Hong-Xia; Li, Jian-Feng; Wang, Cheng-Wei

2018-07-01

The high quality anodic aluminum oxide (AAO) defective photonic crystals (DPCs) have been successfully prepared by using a modified periodic pulse anodization technique including an effective voltage compensating strategy. The test results confirmed that the AAO DPCs were with a perfect regular layered-structure and had a narrow defective photonic band gap (DPBG) with a high quality defective mode. When the rhodamine B (rhB) was absorbed onto the pore walls of the AAO DPCs, it was found that the DPBG blue edge and localized defective mode inside could significantly enhance the photoluminescence (PL) intensity of rhodamine B (rhB), while they were carefully regulated to match with the emission peak position of rhB respectively. Even more intriguing was that the localized defective peak in DPBG had more notable effect on rhB's photoluminescence, 3.1 times higher than that of the control samples under the same conditions. The corresponding mechanism for photoluminescence enhancement was also discussed in detail.

Facile fabrication of high-quality Ag/PS coaxial nanocables based on the mixed mode of soft/hard templates

PubMed Central

Wan, Mimi; Zhao, Wenbo; Peng, Fang; Wang, Qi; Xu, Ping; Mao, Chun; Shen, Jian

2016-01-01

A new kind of high-quality Ag/PS coaxial nanocables can be facilely synthesized by using soft/hard templates method. In order to effectively introduce Ag sources into porous polystyrene (PS) nanotubes which were trapped in porous anodic aluminum oxide (AAO) hard template, Pluronic F127 (F127) was used as guiding agent, soft template and reductant. Meanwhile, ethylene glycol solution was also used as solvent and co-reducing agent to assist in the formation of silver nanowires. The influences of concentration of F127 and reducing reaction time on the formation of Ag/PS coaxial nanocables were discussed. Results indicated that the high-quality Ag/PS coaxial nanocables can be obtained by the mixed mode of soft/hard templates under optimized conditions. This strategy is expected to be extended to design more metal/polymer coaxial nanocables for the benefit of creation of complex and functional nanoarchitectures and components. PMID:27477888

Application of Iron Oxide as a pH-dependent Indicator for Improving the Nutritional Quality

PubMed Central

2016-01-01

Acid food indicators can be used as pH indicators for evaluating the quality and freshness of fermented products during the full course of distribution. Iron oxide particles are hardly suspended in water, but partially or completely agglomerated. The agglomeration degree of the iron oxide particles depends on the pH. The pH-dependent particle agglomeration or dispersion can be useful for monitoring the acidity of food. The zeta potential of iron oxide showed a decreasing trend as the pH increased from 2 to 8, while the point of zero charge (PZC) was observed around at pH 6.0-7.0. These results suggested that the size of the iron oxide particles was affected by the change in pH levels. As a result, the particle sizes of iron oxide were smaller at lower pH than at neutral pH. In addition, agglomeration of the iron oxide particles increased as the pH increased from 2 to 7. In the time-dependent aggregation test, the average particle size was 730.4 nm and 1,340.3 nm at pH 2 and 7, respectively. These properties of iron oxide particles can be used to develop an ideal acid indicator for food pH and to monitor food quality, besides a colorant or nutrient for nutrition enhancement and sensory promotion in food industry. PMID:27482521

Structural and chemical characterization of terbia thin films grown on hexagonally close packed metal substrates

NASA Astrophysics Data System (ADS)

Cartas, William

Rare earth oxides (REOs) exhibit favorable catalytic performance for a diverse set of chemical transformations, including both partial and complete oxidation reactions. I will discuss our efforts to develop thin film systems of terbia for model surface science investigations of a REO that is effectively reducible, and which is thus expected to promote complete oxidation chemistry of adsorbed species. The growth of terbia on Cu(111) is shown to produce a complex surface that exhibits multiple phases of the oxide as well as exposed substrate. Growing the film on Pt(111) results in more uniform, single phase, and closed film. We used low energy electron diffraction (LEED) and scanning tunneling microscopy (STM) to characterize the structural properties of terbia thin films grown on Pt(111) in ultrahigh vacuum (UHV) using physical vapor deposition. We find that the REO grows as a high quality Tb2O 3(111) film, and adopts oxygen-deficient fluorite structures wherein the metal cations form a hexagonal lattice in registry with the Pt(111) substrate, while oxygen vacancies are randomly distributed within the film. The Tb 2O3(111) films are thermally stable when heated to 1000 K in UHV. LEED and STM show that a fraction of the Tb2O3 forms hexagonal islands when first deposited, and further depositions typically result in three dimensional growth of the film. The Tb2O3 (111) / Pt(111) system produces a coincidence structure, seen very clearly in LEED images. We have also found that Tb2O3(111) films can be oxidized in UHV by exposure to plasma-generated atomic oxygen beams. The oxidized films have an estimated TbO2 stoichiometry and decompose to Tb2O3 during heating, with O2 desorption starting at about 500 K. Terbia films oxidized at 90 K show a weakly bound state of oxygen that is likely chemisorbed. Temperature programmed reaction spectroscopy (TPRS) studies using methanol show that increased oxygen in the film does not modify the chemical selectivity of the film; however, the increased oxygen content does increase the activity of the film toward methanol dehydrogenation. We have found that when methanol is adsorbed onto the terbia-Pt(111) system, it reacts to form formaldehyde and water and reduces the surface. The development of high-quality terbia thin films on Pt(111) provides new opportunities to investigate oxidation chemistry on an REO that has distinct reduction and oxidation properties.

Effect of Synthesis on Quality, Electronic Properties and Environmental Stability of Individual monolayer Ti3C2 MXene Flakes

DOE PAGES

Lipatov, A.; Alhabeb, M.; Lukatskaya, Maria R.; ...

2016-01-01

2D transition metal carbide Ti 3C 2T x (T stands for surface termination), the most widely studied MXene, has shown outstanding electrochemical properties and promise for a number of bulk applications. However, electronic properties of individual MXene flakes, which are important for understanding the potential of these materials, remain largely unexplored. Herein, a modified synthetic method is reported for producing high-quality monolayer Ti 3C 2T x flakes. Field-effect transistors (FETs) based on monolayer Ti 3C 2T x flakes are fabricated and their electronic properties are measured. Individual Ti3C2Tx flakes exhibit a high conductivity of 4600 ± 1100 S cm -1more » and field-effect electron mobility of 2.6 ± 0.7 cm2 V -1 s -1. The resistivity of multilayer Ti 3C 2T x films is only one order of magnitude higher than the resistivity of individual flakes, which indicates a surprisingly good electron transport through the surface terminations of different flakes, unlike in many other 2D materials. Finally, the fabricated FETs are used to investigate the environmental stability and kinetics of oxidation of Ti3C2Tx flakes in humid air. The high-quality Ti 3C 2T x flakes are reasonably stable and remain highly conductive even after their exposure to air for more than 24 h. It is demonstrated that after the initial exponential decay the conductivity of Ti 3C 2T x flakes linearly decreases with time, which is consistent with their edge oxidation.« less

76 FR 52283 - Approval and Promulgation of Air Quality Implementation Plans; Pennsylvania; Control of Nitrogen...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-22

... Promulgation of Air Quality Implementation Plans; Pennsylvania; Control of Nitrogen Oxides Emissions From Glass... revisions pertain to the control of nitrogen oxide (NO X ) emissions from glass melting furnaces. EPA is approving these revisions to reduce NO X emissions from glass melting furnaces in accordance with the...

40 CFR 52.231 - Regulations: Sulfur oxides.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 3 2011-07-01 2011-07-01 false Regulations: Sulfur oxides. 52.231... (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS California § 52.231 Regulations: Sulfur oxides... Ambient Air Quality Standard for Sulfur Oxides. (1) Lake County Intrastate Region. (i) Lake County, APCD...

40 CFR 52.231 - Regulations: Sulfur oxides.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 3 2012-07-01 2012-07-01 false Regulations: Sulfur oxides. 52.231... (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS California § 52.231 Regulations: Sulfur oxides... Ambient Air Quality Standard for Sulfur Oxides. (1) Lake County Intrastate Region. (i) Lake County, APCD...

40 CFR 52.231 - Regulations: Sulfur oxides.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 3 2014-07-01 2014-07-01 false Regulations: Sulfur oxides. 52.231... (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS California § 52.231 Regulations: Sulfur oxides... Ambient Air Quality Standard for Sulfur Oxides. (1) Lake County Intrastate Region. (i) Lake County, APCD...

40 CFR 52.231 - Regulations: Sulfur oxides.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Regulations: Sulfur oxides. 52.231... (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS California § 52.231 Regulations: Sulfur oxides... Ambient Air Quality Standard for Sulfur Oxides. (1) Lake County Intrastate Region. (i) Lake County, APCD...

40 CFR 52.231 - Regulations: Sulfur oxides.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 3 2013-07-01 2013-07-01 false Regulations: Sulfur oxides. 52.231... (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS California § 52.231 Regulations: Sulfur oxides... Ambient Air Quality Standard for Sulfur Oxides. (1) Lake County Intrastate Region. (i) Lake County, APCD...

Correlation of gravestone decay and air quality 1960-2010

NASA Astrophysics Data System (ADS)

Mooers, H. D.; Carlson, M. J.; Harrison, R. M.; Inkpen, R. J.; Loeffler, S.

2017-03-01

Evaluation of spatial and temporal variability in surface recession of lead-lettered Carrara marble gravestones provides a quantitative measure of acid flux to the stone surfaces and is closely related to local land use and air quality. Correlation of stone decay, land use, and air quality for the period after 1960 when reliable estimates of atmospheric pollution are available is evaluated. Gravestone decay and SO2 measurements are interpolated spatially using deterministic and geostatistical techniques. A general lack of spatial correlation was identified and therefore a land-use-based technique for correlation of stone decay and air quality is employed. Decadally averaged stone decay is highly correlated with land use averaged spatially over an optimum radius of ≈7 km even though air quality, determined by records from the UK monitoring network, is not highly correlated with gravestone decay. The relationships among stone decay, air-quality, and land use is complicated by the relatively low spatial density of both gravestone decay and air quality data and the fact that air quality data is available only as annual averages and therefore seasonal dependence cannot be evaluated. However, acid deposition calculated from gravestone decay suggests that the deposition efficiency of SO2 has increased appreciably since 1980 indicating an increase in the SO2 oxidation process possibly related to reactions with ammonia.

Polyoxometalates in oxidative delignification of chemical pulps: effect on lignin

Treesearch

Biljana Bujanovic; Sally Ralph; Richard Reiner; Kolby Hirth; Rajai Atalla

2010-01-01

Chemical pulps are produced by chemical delignification of lignocelluloses such as wood or annual non-woody plants. After pulping (e.g., kraft pulping), the remaining lignin is removed by bleaching to produce a high quality, bright paper. The goal of bleaching is to remove lignin from the pulp without a negative effect on the cellulose; for this reason, delignification...

Starch Applications for Delivery Systems

NASA Astrophysics Data System (ADS)

Li, Jason

2013-03-01

Starch is one of the most abundant and economical renewable biopolymers in nature. Starch molecules are high molecular weight polymers of D-glucose linked by α-(1,4) and α-(1,6) glycosidic bonds, forming linear (amylose) and branched (amylopectin) structures. Octenyl succinic anhydride modified starches (OSA-starch) are designed by carefully choosing a proper starch source, path and degree of modification. This enables emulsion and micro-encapsulation delivery systems for oil based flavors, micronutrients, fragrance, and pharmaceutical actives. A large percentage of flavors are encapsulated by spray drying in today's industry due to its high throughput. However, spray drying encapsulation faces constant challenges with retention of volatile compounds, oxidation of sensitive compound, and manufacturing yield. Specialty OSA-starches were developed suitable for the complex dynamics in spray drying and to provide high encapsulation efficiency and high microcapsule quality. The OSA starch surface activity, low viscosity and film forming capability contribute to high volatile retention and low active oxidation. OSA starches exhibit superior performance, especially in high solids and high oil load encapsulations compared with other hydrocolloids. The submission is based on research and development of Ingredion

Structural Characterization of Biogenic Manganese Oxides Produced in Sea Water

NASA Astrophysics Data System (ADS)

Webb, S. M.; Bargar, J. R.; Tebo, B. M.

2003-12-01

Manganese oxides have been coined as the "scavengers of the sea" and play important roles in both marine and freshwater systems. Natural manganese oxide nanoparticles and grain coatings are ubiquitous in the environment and profoundly impact the quality of sediments via their ability to degrade and sequester contaminants. These oxides are believed to form dominantly via oxidation of Mn(II) by marine and freshwater bacteria and have extremely high sorptive capacities for heavy metals. We have used XANES, EXAFS, and synchrotron (SR)-XRD techniques to study biogenic manganese oxides produced by spores of the marine Bacillus sp., strain SG-1 in seawater as a function of reaction time under fully in-situ conditions. The primary biogenic solid-phase Mn oxide product is a hexagonal layered phyollomanganate with an oxidation state similar to that in delta-MnO2. XRD data show the biooxides to have a phyllomanganate 10 basal plane spacing, suggesting the interlayer is hydrated and contains calcium. As the experiment continues, the initial biooxide changes to show triclinic symmetry. Fits to these EXAFS spectra suggest the octahedral layers have low Mn octahedral site vacancies in the lattice and the latyers bend to accommodate Jahn-Teller distortions creating the change in symmetry. The oxides observed in this study as models of Mn(II) bio-oxidation may be representative of the most abundant manganese oxide phase suspended in the oxic and sub-oxic zones of the oceanic water column.

Remote catalyzation for direct formation of graphene layers on oxides.

PubMed

Teng, Po-Yuan; Lu, Chun-Chieh; Akiyama-Hasegawa, Kotone; Lin, Yung-Chang; Yeh, Chao-Hui; Suenaga, Kazu; Chiu, Po-Wen

2012-03-14

Direct deposition of high-quality graphene layers on insulating substrates such as SiO(2) paves the way toward the development of graphene-based high-speed electronics. Here, we describe a novel growth technique that enables the direct deposition of graphene layers on SiO(2) with crystalline quality potentially comparable to graphene grown on Cu foils using chemical vapor deposition (CVD). Rather than using Cu foils as substrates, our approach uses them to provide subliming Cu atoms in the CVD process. The prime feature of the proposed technique is remote catalyzation using floating Cu and H atoms for the decomposition of hydrocarbons. This allows for the direct graphitization of carbon radicals on oxide surfaces, forming isolated low-defect graphene layers without the need for postgrowth etching or evaporation of the metal catalyst. The defect density of the resulting graphene layers can be significantly reduced by tuning growth parameters such as the gas ratios, Cu surface areas, and substrate-to-Cu distance. Under optimized conditions, graphene layers with nondiscernible Raman D peaks can be obtained when predeposited graphite flakes are used as seeds for extended growth. © 2012 American Chemical Society

Hexavalent Chromium Generation within Naturally Structured Soils and Sediments

DOE PAGES

Hausladen, Debra M.; Fendorf, Scott

2017-01-13

Chromium(VI) produced from the oxidation of indigenous Cr(III) minerals is increasingly being recognized as a threat to groundwater quality. A critical determinant of Cr(VI) generation within soils and sediments is the necessary interaction of two low-solubility phases$-$Cr(III) silicates or (hydr)oxides and Mn(III/IV) oxides—that lead to its production. Here in this paper, we investigate the potential for Cr(III) oxidation by Mn oxides within fixed solid matrices common to soils and sediments. Artificial aggregates were constructed from Cr(OH) 3- and Cr 0.25Fe 0.75(OH) 3-coated quartz grains and either mixed with synthetic birnessite or inoculated with the Mn(II)-oxidizing bacterium Leptothrix cholodnii. In aggregatesmore » simulating low organic carbon environments, we observe Cr(VI) concentrations within advecting solutes at levels more than twenty-times the California drinking water standard. Chromium(VI) production is highly dependent on Cr-mineral solubility; increasing Fe-substitution (x = 0 to x = 0.75) decreases the solubility of the solid and concomitantly decreases total Cr(VI) generation by 37%. In environments with high organic carbon, reducing conditions within aggregate cores (microbially) generate sufficient Fe(II) to suppress Cr(VI) efflux. Our results illustrate Cr(VI) generation from reaction with Mn oxides within structured media simulating soils and sediments and provide insight into how fluctuating hydrologic and redox conditions impact coupled processes controlling Cr and Mn cycling.« less

Hexavalent Chromium Generation within Naturally Structured Soils and Sediments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hausladen, Debra M.; Fendorf, Scott

Chromium(VI) produced from the oxidation of indigenous Cr(III) minerals is increasingly being recognized as a threat to groundwater quality. A critical determinant of Cr(VI) generation within soils and sediments is the necessary interaction of two low-solubility phases$-$Cr(III) silicates or (hydr)oxides and Mn(III/IV) oxides—that lead to its production. Here in this paper, we investigate the potential for Cr(III) oxidation by Mn oxides within fixed solid matrices common to soils and sediments. Artificial aggregates were constructed from Cr(OH) 3- and Cr 0.25Fe 0.75(OH) 3-coated quartz grains and either mixed with synthetic birnessite or inoculated with the Mn(II)-oxidizing bacterium Leptothrix cholodnii. In aggregatesmore » simulating low organic carbon environments, we observe Cr(VI) concentrations within advecting solutes at levels more than twenty-times the California drinking water standard. Chromium(VI) production is highly dependent on Cr-mineral solubility; increasing Fe-substitution (x = 0 to x = 0.75) decreases the solubility of the solid and concomitantly decreases total Cr(VI) generation by 37%. In environments with high organic carbon, reducing conditions within aggregate cores (microbially) generate sufficient Fe(II) to suppress Cr(VI) efflux. Our results illustrate Cr(VI) generation from reaction with Mn oxides within structured media simulating soils and sediments and provide insight into how fluctuating hydrologic and redox conditions impact coupled processes controlling Cr and Mn cycling.« less

Protein Quality Control Under Oxidative Stress Conditions

PubMed Central

Dahl, Jan-Ulrik; Gray, Michael J.; Jakob, Ursula

2015-01-01

Accumulation of reactive oxygen and chlorine species (RO/CS) is generally regarded to be a toxic and highly undesirable event, which serves as contributing factor in aging and many age-related diseases. However, it is also put to excellent use during host defense, when high levels of RO/CS are produced to kill invading microorganisms and regulate bacterial colonization. Biochemical and cell biological studies of how bacteria and other microorganisms deal with RO/CS have now provided important new insights into the physiological consequences of oxidative stress, the major targets that need protection, and the cellular strategies employed by organisms to mitigate the damage. This review examines the redox-regulated mechanisms by which cells maintain a functional proteome during oxidative stress. We will discuss the well-characterized redox-regulated chaperone Hsp33, and review recent discoveries demonstrating that oxidative stress-specific activation of chaperone function is a much more widespread phenomenon than previously anticipated. New members of this group include the cytosolic ATPase Get3 in yeast, the E. coli protein RidA, and the mammalian protein α2-macroglobin. We will conclude our review with recent evidence showing that inorganic polyphosphate (polyP), whose accumulation significantly increases bacterial oxidative stress resistance, works by a protein-like chaperone mechanism. Understanding the relationship between oxidative and proteotoxic stresses will improve our understanding of both host-microbe interactions and of how mammalian cells combat the damaging side effects of uncontrolled RO/CS production, a hallmark of inflammation. PMID:25698115

In-situ sequential laser transfer and laser reduction of graphene oxide films

NASA Astrophysics Data System (ADS)

Papazoglou, S.; Petridis, C.; Kymakis, E.; Kennou, S.; Raptis, Y. S.; Chatzandroulis, S.; Zergioti, I.

2018-04-01

Achieving high quality transfer of graphene on selected substrates is a priority in device fabrication, especially where drop-on-demand applications are involved. In this work, we report an in-situ, fast, simple, and one step process that resulted in the reduction, transfer, and fabrication of reduced graphene oxide-based humidity sensors, using picosecond laser pulses. By tuning the laser illumination parameters, we managed to implement the sequential printing and reduction of graphene oxide flakes. The overall process lasted only a few seconds compared to a few hours that our group has previously published. DC current measurements, X-Ray Photoelectron Spectroscopy, X-Ray Diffraction, and Raman Spectroscopy were employed in order to assess the efficiency of our approach. To demonstrate the applicability and the potential of the technique, laser printed reduced graphene oxide humidity sensors with a limit of detection of 1700 ppm are presented. The results demonstrated in this work provide a selective, rapid, and low-cost approach for sequential transfer and photochemical reduction of graphene oxide micro-patterns onto various substrates for flexible electronics and sensor applications.

High average-power 2 μm radiation generated by intracavity KTP OPO

NASA Astrophysics Data System (ADS)

He, Guangyuan; Guo, Jing; Jiao, Zhongxing; Wang, Biao

2015-09-01

A high average-power 2 μm laser with good beam quality based on an intracavity potassium titanium oxide phosphate (KTP) optical parametric oscillator (OPO) is demonstrated. A concave lens is used in the 1064 nm Nd:YAG pumped laser cavity to compensate for the thermal lensing of the laser rod. The cavity length of the KTP OPO is enlarged to improve the 2 μm beam quality. The maximum average output of the 2 μm laser is up to 18 W at 7 kHz with M 2 less than 6 and pulse width of 70 ns. The FWHM of the signal and idle lights are both less than 3 nm.

Eggshell Spottiness Reflects Maternally Transferred Antibodies in Blue Tits

PubMed Central

Holveck, Marie-Jeanne; Grégoire, Arnaud; Staszewski, Vincent; Guerreiro, Romain; Perret, Philippe; Boulinier, Thierry; Doutrelant, Claire

2012-01-01

Blue-green and brown-spotted eggshells in birds have been proposed as sexual signals of female physiological condition and egg quality, reflecting maternal investment in the egg. Testing this hypothesis requires linking eggshell coloration to egg content, which is lacking for brown protoporphyrin-based pigmentation. As protoporphyrins can induce oxidative stress, and a large amount in eggshells should indicate either high female and egg quality if it reflects the female's high oxidative tolerance, or conversely poor quality if it reflects female physiological stress. Different studies supported either predictions but are difficult to compare given the methodological differences in eggshell-spottiness measurements. Using the blue tit Cyanistes caeruleus as a model species, we aimed at disentangling both predictions in testing if brown-spotted eggshell could reflect the quality of maternal investment in antibodies and carotenoids in the egg, and at improving between-study comparisons in correlating several common measurements of eggshell coloration (spectral and digital measures, spotted surface, pigmentation indices). We found that these color variables were weakly correlated highlighting the need for comparable quantitative measurements between studies and for multivariate regressions incorporating several eggshell-color characteristics. When evaluating the potential signaling function of brown-spotted eggshells, we thus searched for the brown eggshell-color variables that best predicted the maternal transfer of antibodies and carotenoids to egg yolks. We also tested the effects of several parental traits and breeding parameters potentially affecting this transfer. While eggshell coloration did not relate to yolk carotenoids, the eggs with larger and less evenly-distributed spots had higher antibody concentrations, suggesting that both the quantity and distribution of brown pigments reflected the transfer of maternal immune compounds in egg yolks. As yolk antibody concentrations were also positively related to key proxies of maternal quality (egg volume, number, yellow feather brightness, tarsus length), eggshells with larger spots concentrated at their broad pole may indicate higher-quality eggs. PMID:23226272

Photocatalytic activity of binary metal oxide nanocomposites of CeO2/CdO nanospheres: Investigation of optical and antimicrobial activity.

PubMed

Magdalane, C Maria; Kaviyarasu, K; Vijaya, J Judith; Siddhardha, Busi; Jeyaraj, B

2016-10-01

We report the synthesis of high quality CeO2-CdO binary metal oxide nanocomposites were synthesized by a simple chemical precipitation and hydrothermal method. Cerium nitrate and cadmium nitrate were used as precursors. Composition, structure and morphology of the nanocomposites were analyzed by X-ray diffraction (XRD) and high resolution transmission electron microscopy (HRTEM). XRD pattern proves that the final product has cubic phase and the particle size diameter of the nanocomposites are 27nm, XRD results also indicated that the crystalline properties of the nanocomposite were improved without affecting the parent lattice, FESEM analysis indicates that the product is composed of spherical particles in clusters. The morphological and optical properties of CeO2-CdO nanosamples were characterized by HRTEM and DRS spectroscopy. The IR results showed high purity of products and indicated that the nanocomposites are made up of CeO2 and CdO bonds. Absorption spectra exhibited an upward shift in characteristic peaks caused by the addition of transition metal oxide, suggesting that crystallinity of both the metal oxide is improved due to specific doping level. TGA plots further confirmed the purity and stability of nanomaterials prepared. Hence the nanocomposite has cubic crystal lattice and form a homogeneous solid structure. From the result, Cd(2+) ions are embedded in the cubic crystal lattice of ceria. The growth rate increases which are ascribed to the cationic doping with a lower valence cation. Ce-Cd binary metal oxide nanocomposites showed antibacterial activity, it showed the better growth inhibition towards p.aeruginosa. Exploit of photodegradation and photocatalytic activity of large scale synthesis of CeO2-CdO binary metal oxide nanocomposites was reported. Copyright © 2016 Elsevier B.V. All rights reserved.

Defect-mediated room temperature ferromagnetism in vanadium dioxide thin films

NASA Astrophysics Data System (ADS)

Yang, Tsung-Han; Nori, Sudhakar; Zhou, Honghui; Narayan, Jagdish

2009-09-01

High quality epitaxial undoped vanadium oxide (VO2) thin films on c-plane sapphire (0001) substrate have been grown using pulsed laser deposition technique. The as-grown films exhibited excellent structural and transport properties without requiring further annealing treatments for these oxygen-deficient oxide films. The epitaxial growth has been achieved via domain matching epitaxy, where matching of integral multiples of planes occurs across the film-substrate interface. The magnetic properties of vanadium oxide (VO2) films investigated at different temperatures in the range of 10-360 K showed significant magnetic hysteresis as well as saturation of the magnetic moment. The origin of ferromagnetic properties with an estimated Curie temperature above 500 K is discussed in the absence of magnetic impurities in VO2 thin films as determined by x-ray photoelectron spectroscopy, x-ray diffraction, and transmission electron microscopy.

Surface cleaning and pure nitridation of GaSb by in-situ plasma processing

NASA Astrophysics Data System (ADS)

Gotow, Takahiro; Fujikawa, Sachie; Fujishiro, Hiroki I.; Ogura, Mutsuo; Chang, Wen Hsin; Yasuda, Tetsuji; Maeda, Tatsuro

2017-10-01

A clean and flat GaSb surface without native oxides has been attained by H2 plasma cleaning and subsequent in-situ N2 plasma nitridation process at 300 oC. The mechanisms of thermal desorption behavior of native oxides on GaSb have been studied by thermal desorption spectroscopy (TDS) analysis. The suitable heat treatment process window for preparing a clean GaSb surface is given. Auger electron spectroscopy (AES) analysis indicates that native oxides were completely removed on the GaSb surface after H2 plasma exposure and the pure nitridation of the clean GaSb surface was obtained at a relatively low temperature of 300 °C. This pure nitridation of GaSb have a possibility to be used as a passivation layer for high quality GaSb MOS devices.

Improvement of Bipolar Switching Properties of Gd:SiOx RRAM Devices on Indium Tin Oxide Electrode by Low-Temperature Supercritical CO2 Treatment.

PubMed

Chen, Kai-Huang; Chang, Kuan-Chang; Chang, Ting-Chang; Tsai, Tsung-Ming; Liang, Shu-Ping; Young, Tai-Fa; Syu, Yong-En; Sze, Simon M

2016-12-01

Bipolar switching resistance behaviors of the Gd:SiO2 resistive random access memory (RRAM) devices on indium tin oxide electrode by the low-temperature supercritical CO2-treated technology were investigated. For physical and electrical measurement results obtained, the improvement on oxygen qualities, properties of indium tin oxide electrode, and operation current of the Gd:SiO2 RRAM devices were also observed. In addition, the initial metallic filament-forming model analyses and conduction transferred mechanism in switching resistance properties of the RRAM devices were verified and explained. Finally, the electrical reliability and retention properties of the Gd:SiO2 RRAM devices for low-resistance state (LRS)/high-resistance state (HRS) in different switching cycles were also measured for applications in nonvolatile random memory devices.

Towards large-scale plasma-assisted synthesis of nanowires

NASA Astrophysics Data System (ADS)

Cvelbar, U.

2011-05-01

Large quantities of nanomaterials, e.g. nanowires (NWs), are needed to overcome the high market price of nanomaterials and make nanotechnology widely available for general public use and applications to numerous devices. Therefore, there is an enormous need for new methods or routes for synthesis of those nanostructures. Here plasma technologies for synthesis of NWs, nanotubes, nanoparticles or other nanostructures might play a key role in the near future. This paper presents a three-dimensional problem of large-scale synthesis connected with the time, quantity and quality of nanostructures. Herein, four different plasma methods for NW synthesis are presented in contrast to other methods, e.g. thermal processes, chemical vapour deposition or wet chemical processes. The pros and cons are discussed in detail for the case of two metal oxides: iron oxide and zinc oxide NWs, which are important for many applications.

Direct Growth of Graphene Film on Germanium Substrate

PubMed Central

Wang, Gang; Zhang, Miao; Zhu, Yun; Ding, Guqiao; Jiang, Da; Guo, Qinglei; Liu, Su; Xie, Xiaoming; Chu, Paul K.; Di, Zengfeng; Wang, Xi

2013-01-01

Graphene has been predicted to play a role in post-silicon electronics due to the extraordinary carrier mobility. Chemical vapor deposition of graphene on transition metals has been considered as a major step towards commercial realization of graphene. However, fabrication based on transition metals involves an inevitable transfer step which can be as complicated as the deposition of graphene itself. By ambient-pressure chemical vapor deposition, we demonstrate large-scale and uniform depositon of high-quality graphene directly on a Ge substrate which is wafer scale and has been considered to replace conventional Si for the next generation of high-performance metal-oxide-semiconductor field-effect transistors (MOSFETs). The immiscible Ge-C system under equilibrium conditions dictates graphene depositon on Ge via a self-limiting and surface-mediated process rather than a precipitation process as observed from other metals with high carbon solubility. Our technique is compatible with modern microelectronics technology thus allowing integration with high-volume production of complementary metal-oxide-semiconductors (CMOS). PMID:23955352

40 CFR 52.1475 - Control strategy and regulations: Sulfur oxides.

Code of Federal Regulations, 2012 CFR

2012-07-01

...: Sulfur oxides. 52.1475 Section 52.1475 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... § 52.1475 Control strategy and regulations: Sulfur oxides. (a) The requirements of subpart G of this... National Ambient Air Quality Standards for sulfur oxides in the Nevada Intrastate Region. (b) Article 8.1.3...

40 CFR 52.1475 - Control strategy and regulations: Sulfur oxides.

Code of Federal Regulations, 2013 CFR

2013-07-01

...: Sulfur oxides. 52.1475 Section 52.1475 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... § 52.1475 Control strategy and regulations: Sulfur oxides. (a) The requirements of subpart G of this... National Ambient Air Quality Standards for sulfur oxides in the Nevada Intrastate Region. (b) Article 8.1.3...

40 CFR 52.1475 - Control strategy and regulations: Sulfur oxides.

Code of Federal Regulations, 2011 CFR

2011-07-01

...: Sulfur oxides. 52.1475 Section 52.1475 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... § 52.1475 Control strategy and regulations: Sulfur oxides. (a) The requirements of subpart G of this... National Ambient Air Quality Standards for sulfur oxides in the Nevada Intrastate Region. (b) Article 8.1.3...

40 CFR 52.1475 - Control strategy and regulations: Sulfur oxides.

Code of Federal Regulations, 2014 CFR

2014-07-01

...: Sulfur oxides. 52.1475 Section 52.1475 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... § 52.1475 Control strategy and regulations: Sulfur oxides. (a) The requirements of subpart G of this... National Ambient Air Quality Standards for sulfur oxides in the Nevada Intrastate Region. (b) Article 8.1.3...

40 CFR 52.1475 - Control strategy and regulations: Sulfur oxides.

Code of Federal Regulations, 2010 CFR

2010-07-01

...: Sulfur oxides. 52.1475 Section 52.1475 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... § 52.1475 Control strategy and regulations: Sulfur oxides. (a) The requirements of subpart G of this... National Ambient Air Quality Standards for sulfur oxides in the Nevada Intrastate Region. (b) Article 8.1.3...

Air Quality Criteria for Sulfur Oxides.

ERIC Educational Resources Information Center

National Air Pollution Control Administration (DHEW), Washington, DC.

Included is a literature review which comprehensively discusses knowledge of the sulfur oxides commonly found in the atmosphere. The subject content is represented by the 10 chapter titles: Physical and Chemical Properties and the Atmospheric Reactions of the Oxides of Sulfur; Sources and Methods of Measurements of Sulfur Oxides in the Atmosphere;…

High-quality metal oxide core/shell nanowire arrays on conductive substrates for electrochemical energy storage.

PubMed

Xia, Xinhui; Tu, Jiangping; Zhang, Yongqi; Wang, Xiuli; Gu, Changdong; Zhao, Xin-Bing; Fan, Hong Jin

2012-06-26

The high performance of a pseudocapacitor electrode relies largely on a scrupulous design of nanoarchitectures and smart hybridization of bespoke active materials. We present a powerful two-step solution-based method for the fabrication of transition metal oxide core/shell nanostructure arrays on various conductive substrates. Demonstrated examples include Co(3)O(4) or ZnO nanowire core and NiO nanoflake shells with a hierarchical and porous morphology. The "oriented attachment" and "self-assembly" crystal growth mechanisms are proposed to explain the formation of the NiO nanoflake shell. Supercapacitor electrodes based on the Co(3)O(4)/NiO nanowire arrays on 3D macroporous nickel foam are thoroughly characterized. The electrodes exhibit a high specific capacitance of 853 F/g at 2 A/g after 6000 cycles and an excellent cycling stability, owing to the unique porous core/shell nanowire array architecture, and a rational combination of two electrochemically active materials. Our growth approach offers a new technique for the design and synthesis of transition metal oxide or hydroxide hierarchical nanoarrays that are promising for electrochemical energy storage, catalysis, and gas sensing applications.

Facile photoreduction of graphene oxide by an NAD(P)H model: Hantzsch 1,4-dihydropyridine.

PubMed

Zhang, Hui-Hui; Liu, Qiang; Feng, Ke; Chen, Bin; Tung, Chen-Ho; Wu, Li-Zhu

2012-05-29

To make "clean" reduced GO sheets in high quality and in large scale, a natural reduced nicotinamine adenine dinucleotide NAD(P)H model, Hantzsch 1,4-dihydropyridine (HEH), is used as a mild organic photoreductant in this work. Benefiting from the intense absorption of HEH in the range of 300-420 nm, the graphene oxide (GO) can be readily reduced by HEH under UV light irradiation (λ > 320 nm) to afford single or few-layer reduced graphene oxide at room temperature. Studies on reduction extent reveal that both irradiation time and concentration ratio of HEH to GO are important for effective reduction of GO under UV light. The as-prepared photochemically reduced graphene oxide (PRGO) dispersion is stable without the need for any polymeric or surfactant stabilizers. Simply by extraction treatment, the "clean" PRGO sheets can be obtained in large quantities, and its conductivity approaches to 4680 S·m(-1) that is the highest value reported by photochemical approaches so far.

Performance characteristics of rubber seed oil biodiesel

NASA Astrophysics Data System (ADS)

Liu, P.; Qin, M.; Wu, J.; Chen, B. S.

2018-01-01

The lubricity, ignition quality, oxidative stability, low temperature flow property and elastomeric compatibility of rubber seed oil biodiesel(RSM) were evaluated and compared with conventional petro-diesel. The results indicated that RSM and its blends with petro-diesel possessed outstanding lubricity manifested by sharp decrease in wear scar diameters in the high-frequency reciprocating rig(HFRR) testing. They also provided acceptable flammability and cold flow property,although the cetane numbers (CN) and cold filter plugging points(CFPP) of biodiesel blends slightly decreased with increasing contents of petro-diesel. However, RSM proved to be very susceptible to oxidation at elevated temperatures during prolonged oxidation durations, characterized by increased peroxide values, viscosity, acid values and isooctane insolubles. The oxidation stability of RSM could be significantly improved by antioxidants such as BD100, a phenol antioxidant produced by Ciba corporation. Furthermore, RSM provided poor compatibility with some elastomeric rubbers such as polyacrylate, nitrile-butadiene and chloroprene, but was well compatible with the hydrogenated nitrile-butadiene elastomer.

Influence of some packaging materials and of natural tocopherols on the sensory properties of breakfast cereals.

PubMed

Paradiso, Vito M; Caponio, Francesco; Summo, Carmine; Gomes, Tommaso

2014-04-01

The combined effect of natural antioxidants and packaging materials on the quality decay of breakfast cereals during storage was evaluated. Corn flakes were produced on industrial scale, using different packages and adding natural tocopherols to the ingredients, and stored for 1 year. The samples were then submitted to sensory analysis and HS-solid phase microextraction/gas chromatography/mass spectrometry (SPME/GC/MS) analysis. The packaging had a significant influence on the sensory profile of the aged product: metallized polypropylene gave the highest levels of oxidation compounds and sensory defects. The sensory profile was improved using polypropylene and especially high-density polyethylene. Natural tocopherols reduced the sensory decay of the flakes and the oxidative evolution of the volatile profile. They gave the most remarkable improvement in polypropylene (either metallized or not) packs. Polypropylene showed a barrier effect on the scalping of volatiles outside of the pack. This led to higher levels of oxidation volatiles and faster rates of the further oxidative processes involving the volatiles.

Topological Dirac semimetal phase in Pd and Pt oxides

NASA Astrophysics Data System (ADS)

Li, Gang; Yan, Binghai; Wang, Zhijun; Held, Karsten

2017-01-01

Topological Dirac semimetals (DSMs) exhibit nodal points through which energy bands disperse linearly in three-dimensional (3D) momentum space, a 3D analog of graphene. The first experimentally confirmed DSMs with a pair of Dirac points (DPs), Na3Bi and Cd3As2 , show topological surface Fermi arc states and exotic magnetotransport properties, boosting the interest in the search for stable and nontoxic DSM materials. Based on density-functional theory and dynamical mean-field theory calculations, we predict a family of palladium and platinum oxides to be robust 3D DSMs with three pairs of Dirac points that are well separated from bulk bands. The Fermi arcs at the surface display a Lifshitz transition upon a continuous change of the chemical potential. Corresponding oxides are already available as high-quality single crystals, an excellent precondition for the verification of our predictions by photoemission and magnetotransport experiments, extending DSMs to the versatile family of transition-metal oxides.

Electrochemical deposition onto self-assembled monolayers: new insights into micro- and nanofabrication.

PubMed

Schilardi, Patricia L; Dip, Patricio; dos Santos Claro, Paula C; Benítez, Guillermo A; Fonticelli, Mariano H; Azzaroni, Omar; Salvarezza, Roberto C

2005-12-16

Pattern transfer with high resolution is a frontier topic in the emerging field of nanotechnologies. Electrochemical molding is a possible route for nanopatterning metal, alloys and oxide surfaces with high resolution in a simple and inexpensive way. This method involves electrodeposition onto a conducting master covered by a self-assembled alkanethiolate monolayer (SAMs). This molecular film enables direct surface-relief pattern transfer from the conducting master to the inner face of the electrodeposit, and also allows an easy release of the electrodeposited film due their excellent anti-adherent properties. Replicas of the original conductive master can be also obtained by a simple two-step procedure. SAM quality and stability under electrodeposition conditions combined with the formation of smooth electrodeposits are crucial to obtain high-quality pattern transfer with sub-50 nm resolution.

Investigation of Optical Properties of Zinc Oxide Photodetector

NASA Astrophysics Data System (ADS)

Chism, Tyler

UV photodetection devices have many important applications for uses in biological detection, gas sensing, weaponry detection, fire detection, chemical analysis, and many others. Today's photodetectors often utilize semiconductors such as GaAs to achieve high responsivity and sensitivity. Zinc oxide, unlike many other semiconductors, is cheap, abundant, non-toxic, and easy to grow different morphologies at the micro and nano scale. With the proliferation of these devices also comes the impending need to further study optics and photonics in relation to phononics and plasmonics, and the general principles underlying the interaction of photons with solid state matter and, specifically, semiconductors. For this research a metal-semiconductor-metal UV photodetector has been fabricated by using a quartz substrate on top of which was deposited micropatterned gold in an interdigitated electrode design. On this, sparsely coated zinc oxide nano trees were hydrothermally grown. The UV photodetection device showed promise for detection applications, especially because zinc oxide is also very thermally stable, a quality which is highly sought after in today's UV photodetectors. Furthermore, the newly synthesized photodetector was used to investigate optical properties and how they respond to different stimuli. It was discovered that the photons transmitted through the sparsely coated zinc oxide nano trees decreased as the voltage across the device increased. This research is aimed at better understanding photons interaction with matter and also to open the door for new devices with tunable optical properties such as transmission.

Oxynitride glass production procedure

DOEpatents

Weidner, Jerry R.; Schuetz, Stanley T.; O'Brien, Michael H.

1991-01-01

The invention is a process for the preparation of high quality oxynitride glasses without resorting to high pressures. Nitrogen-containing compounds such as Si.sub.3 N.sub.4 are first encapsulated in a low melting temperature glass. Particles of the encapsulated nitrogen-containing compound are mixed with other oxide glass-formers and melted in an atmosphere of flowing nitrogen and in the presence of buffering gas to form the oxynitride glass. Glasses containing up to 15 at % nitrogen have been prepared by this method.

Efficient lasing in Yb:(YLa){sub 2}O{sub 3} ceramics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Snetkov, I L; Mukhin, I B; Palashov, O V

2015-02-28

A high-optical-quality sample of Yb{sub 0.1}Y{sub 1.7}La{sub 0.2}O{sub 3} ceramics is prepared using a recently developed technique of selfpropagating high-temperature synthesis of rare-earth-doped yttrium oxide nanopowder from acetate – nitrates of metals. Its optical and spectral characteristics are studied, and quasi-cw lasing at a wavelength of 1033 nm is achieved with a power of 7 W and a slope efficiency of 25%. (lasers)

Combustion synthesized indium-tin-oxide (ITO) thin film for source/drain electrodes in all solution-processed oxide thin-film transistors

NASA Astrophysics Data System (ADS)

Tue, Phan Trong; Inoue, Satoshi; Takamura, Yuzuru; Shimoda, Tatsuya

2016-06-01

We report combustion solution synthesized (SCS) indium-tin-oxide (ITO) thin film, which is a well-known transparent conductive oxide, for source/drain (S/D) electrodes in solution-processed amorphous zirconium-indium-zinc-oxide TFT. A redox-based combustion synthetic approach is applied to ITO thin film using acetylacetone as a fuel and metal nitrate as oxidizer. The structural and electrical properties of SCS-ITO precursor solution and thin films were systematically investigated with changes in tin concentration, indium metal precursors, and annealing conditions such as temperature, time, and ambient. It was found that at optimal conditions the SCS-ITO thin film exhibited high crystalline quality, atomically smooth surface (RMS ~ 4.1 Å), and low electrical resistivity (4.2 × 10-4 Ω cm). The TFT using SCS-ITO film as the S/D electrodes showed excellent electrical properties with negligible hysteresis. The obtained "on/off" current ratio, subthreshold swing factor, subthreshold voltage, and field-effect mobility were 5 × 107, 0.43 V/decade, 0.7 V, and 2.1 cm2/V s, respectively. The performance and stability of the SCS-ITO TFT are comparable to those of the sputtered-ITO TFT, emphasizing that the SCS-ITO film is a promising candidate for totally solution-processed oxide TFTs.

DNA damage in lens epithelium of cataract patients in vivo and ex vivo.

PubMed

Øsnes-Ringen, Oyvind; Azqueta, Amaia O; Moe, Morten C; Zetterström, Charlotta; Røger, Magnus; Nicolaissen, Bjørn; Collins, Andrew R

2013-11-01

DNA damage has been described in the human cataractous lens epithelium, and oxidative stress generated by UV radiation and endogenous metabolic processes has been suggested to play a significant role in the pathogenesis of cataract. In this study, the aim was to explore the quality and relative quantity of DNA damage in lens epithelium of cataract patients in vivo and after incubation in a cell culture system. Capsulotomy specimens were analysed, before and after 1 week of ex vivo cultivation, using the comet assay to measure DNA strand breaks, oxidized purine and pyrimidine bases and UV-induced cyclobutane pyrimidine dimers. DNA strand breaks were barely detectable, oxidized pyrimidines and pyrimidine dimers were present at low levels, whereas there was a relatively high level of oxidized purines, which further increased after cultivation. The observed levels of oxidized purines in cataractous lens epithelium may support a theory consistent with light damage and oxidative stress as mediators of molecular damage to the human lens epithelium. Damage commonly associated with UV-B irradiation was relatively low. The levels of oxidized purines increased further in a commonly used culture system. This is of interest considering the importance and versatility of ex vivo systems in studies exploring the pathogenesis of cataract. © 2012 The Authors. Acta Ophthalmologica © 2012 Acta Ophthalmologica Scandinavica Foundation.

Probiotic supplementation and fast freezing to improve quality attributes and oxidation stability of frozen chicken breast muscle

USDA-ARS?s Scientific Manuscript database

The objective of this study was to determine the effects of probiotic supplementation and fast freezing on quality attributes and oxidation stability of frozen/thawed chicken breast meat. Broilers were fed with a basal diet or the basal diet plus 250 ppm Sporulin (three strains of Bacillus subtilis)...

76 FR 34021 - Approval and Promulgation of Air Quality Implementation Plans; Pennsylvania; Control of Nitrogen...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-10

... Promulgation of Air Quality Implementation Plans; Pennsylvania; Control of Nitrogen Oxides Emissions From Glass... Pennsylvania. This revision pertains to the control of nitrogen oxide (NO X ) emissions from glass melting... Plan for the control of NO X from glass melting furnaces. I. Background The SIP revision consists of a...

40 CFR 52.675 - Control strategy: Sulfur oxides-Eastern Idaho Intrastate Air Quality Control Region.

Code of Federal Regulations, 2014 CFR

2014-07-01

... of Sulfur Oxide Emissions from Sulfuric Acid Plants) of the “Rules and Regulations for the Control of... have previously been established for certain existing acid plants in this Air Quality Control Region... apply to existing acid plants with approved or promulgated emission limits that are more stringent than...

40 CFR 52.675 - Control strategy: Sulfur oxides-Eastern Idaho Intrastate Air Quality Control Region.

Code of Federal Regulations, 2013 CFR

2013-07-01

... of Sulfur Oxide Emissions from Sulfuric Acid Plants) of the “Rules and Regulations for the Control of... have previously been established for certain existing acid plants in this Air Quality Control Region... apply to existing acid plants with approved or promulgated emission limits that are more stringent than...

40 CFR 52.675 - Control strategy: Sulfur oxides-Eastern Idaho Intrastate Air Quality Control Region.

Code of Federal Regulations, 2012 CFR

2012-07-01

... of Sulfur Oxide Emissions from Sulfuric Acid Plants) of the “Rules and Regulations for the Control of... have previously been established for certain existing acid plants in this Air Quality Control Region... apply to existing acid plants with approved or promulgated emission limits that are more stringent than...

40 CFR 52.675 - Control strategy: Sulfur oxides-Eastern Idaho Intrastate Air Quality Control Region.

Code of Federal Regulations, 2010 CFR

2010-07-01

... of Sulfur Oxide Emissions from Sulfuric Acid Plants) of the “Rules and Regulations for the Control of... have previously been established for certain existing acid plants in this Air Quality Control Region... apply to existing acid plants with approved or promulgated emission limits that are more stringent than...

40 CFR 52.675 - Control strategy: Sulfur oxides-Eastern Idaho Intrastate Air Quality Control Region.

Code of Federal Regulations, 2011 CFR

2011-07-01

... of Sulfur Oxide Emissions from Sulfuric Acid Plants) of the “Rules and Regulations for the Control of... have previously been established for certain existing acid plants in this Air Quality Control Region... apply to existing acid plants with approved or promulgated emission limits that are more stringent than...

Workshop to Obtain Input on Draft Materials for the Integrated Science Assessment (ISA) for Sulfur Oxides (SOx): Health Criteria

EPA Science Inventory

As part of the review of the air quality criteria for sulfur oxides (SO_X) and primary (health-based) National Ambient Air Quality Standards (NAAQS) for sulfur dioxide (SO₂), EPA is announcing a teleconference workshop to evaluate preliminary draft materials ...

Generalized syntheses of nanocrystal-graphene hybrids in high-boiling-point organic solvents.

PubMed

Pang, Danny Wei-Ping; Yuan, Fang-Wei; Chang, Yan-Cheng; Li, Guo-An; Tuan, Hsing-Yu

2012-08-07

Nanocrystal-graphene have been proposed as a new kind of promising hybrid for a wide range of application areas including catalysts, electronics, sensors, biomedicine, and energy storage, etc. Although a variety of methods have been developed for the preparation of hybrids, a facile and general synthetic approach is still highly required. In this study, nanocrystal-graphene hybrids were successfully synthesized in high-boiling-point organic solvents. Graphene oxide (GO) nanosheets were modified by oleylamine (OLA) to form a OLA-GO complex in order to be readily incorporated into hydrophobic synthesis. A rich library of highly crystalline nanocrystals, with types including noble metal, metal oxide, magnetic material and semiconductor were successfully grown on chemically converted graphene (CCG), which is simultaneously reduced from GO during the synthesis. High boiling-point solvents afford sufficient thermal energy to assure the high-quality crystalline nature of NCs, therefore the post-annealing process is obviated. Controlled experiments revealed that OLA-GO triggers heterogeneous nucleation and serves as excellent nuclei anchorage media. The protocol developed here brings one step closer to achieve "unity in diversity" on the preparation of nanocrystal-graphene hybrids.

Influence of smoking and packaging methods on lipid stability and microbial quality of Capelin (Mallotus villosus) and Sardine (Sardinella gibossa)

PubMed Central

Cyprian, Odoli O; Van Nguyen, Minh; Sveinsdottir, Kolbrun; Jonsson, Asbjorn; Tomasson, Tumi; Thorkelsson, Gudjon; Arason, Sigurjon

2015-01-01

Lipid and microbial quality of smoked capelin (two groups differing in lipid content) and sardine was studied, with the aim of introducing capelin in the smoked sardine markets. Lipid hydrolysis (phospholipid and free fatty acids) and oxidation index (hydroperoxides and thiobarbituric acid-reactive substances), fatty acid composition, and total viable count were measured in raw and packaged smoked fish during chilled storage (day 2, 10, 16, 22, 28). Lipid hydrolysis was more pronounced in low lipid capelin, whereas accelerated lipid oxidation occurred in high lipid capelin. Muscle lipid was less stable in sardine than capelin. Essential polyunsaturated fatty acids (eicosapentaenoic acid and docosahexaenoic acid) constituted 12% of fatty acids in capelin and 19% in sardine. Vacuum packaging as well as hot smoking retarded bacterial growth, recording counts of ≤log 5 CFU/g compared to ≥log 7CFU/g in cold smoked air packaged. Smoked low lipid capelin was considered an alternative for introduction in smoked sardine markets. PMID:26405526

Formula of an ideal carbon nanomaterial supercapacitor

NASA Astrophysics Data System (ADS)

Samuilova, Larissa; Frenkel, Alexander; Samuilov, Vladimir

2014-03-01

Supercapacitors exhibit great potential as high-performance energy sources for a large variety of potential applications, ranging from consumer electronics through wearable optoelectronics to hybrid electric vehicles. We focuse on carbon nanomaterials, especially carbon nanotube films, 3-D graphene, graphene oxide due to their high specific surface area, excellent electrical and mechanical properties. We have developed a simple approach to lower the equivalent series resistance by fabricating electrodes of arbitrary thickness using carbon nanotube films and reduced graphene oxide based composites. Besides of the problem of increasing of the capacitance, the minimization of the loss tangent (dissipation factor) is marginal for the future development of the supercapacitors. This means, not only a very well developed surface area of the electrodes, but the role of the good quality of the porous separator and the electrolyte are important. We address these factors as well.

Non-noble metal Cu-loaded TiO2 for enhanced photocatalytic H2 production.

PubMed

Foo, Wei Jian; Zhang, Chun; Ho, Ghim Wei

2013-01-21

Here we have demonstrated the preparation of high-quality, monodispersed and tunable phases of Cu nanoparticles. Structural and chemical composition studies depict the evolution of Cu-Cu(2)O-CuO nanoparticles at various process stages. The loading of Cu and Cu oxide nanoparticles on TiO(2) catalyst has enhanced the photocatalytic H(2) production. Comparatively, H(2) treatment produces well-dispersed Cu nanoparticles with thin oxide shells that show the highest H(2) production amongst the samples. The relatively higher photocatalytic performance is deemed to result from reduced structural defects, higher surface area and dispersivity as well as favorable charge transfer, which inhibits recombination. The Cu nanoparticles are shown to be a promising alternative to noble metal-loaded TiO(2) catalyst systems due to their low cost and high performance in photocatalytic applications.

Instrumentation for air quality measurements.

NASA Technical Reports Server (NTRS)

Loewenstein, M.

1973-01-01

Comparison of the new generation of air quality monitoring instruments with some more traditional methods. The first generation of air quality measurement instruments, based on the use of oxidant coulometric cells, nitrogen oxide colorimetry, carbon monoxide infrared analyzers, and other types of detectors, is compared with new techniques now coming into wide use in the air monitoring field and involving the use of chemiluminescent reactions, optical absorption detectors, a refinement of the carbon monoxide infrared analyzer, electrochemical cells based on solid electrolytes, and laser detectors.

Nitrous oxide for the management of labor pain: a systematic review.

PubMed

Likis, Frances E; Andrews, Jeffrey C; Collins, Michelle R; Lewis, Rashonda M; Seroogy, Jeffrey J; Starr, Sarah A; Walden, Rachel R; McPheeters, Melissa L

2014-01-01

We systematically reviewed evidence addressing the effectiveness of nitrous oxide for the management of labor pain, the influence of nitrous oxide on women's satisfaction with their birth experience and labor pain management, and adverse effects associated with nitrous oxide for labor pain management. We searched the MEDLINE, EMBASE, and Cumulative Index to Nursing and Allied Health Literature (CINAHL) databases for articles published in English. The study population included pregnant women in labor intending a vaginal birth, birth attendees or health care providers who may be exposed to nitrous oxide during labor, and the fetus/neonate. We identified a total of 58 publications, representing 59 distinct study populations: 2 studies were of good quality, 11 fair, and 46 poor. Inhalation of nitrous oxide provided less effective pain relief than epidural analgesia, but the quality of studies was predominately poor. The heterogeneous outcomes used to assess women's satisfaction with their birth experience and labor pain management made synthesis of studies difficult. Most maternal adverse effects reported in the literature were unpleasant side effects that affect tolerability, such as nausea, vomiting, dizziness, and drowsiness. Apgar scores in newborns whose mothers used nitrous oxide were not significantly different from those of newborns whose mothers used other labor pain management methods or no analgesia. Evidence about occupational harms and exposure was limited. The literature addressing nitrous oxide for the management of labor pain includes few studies of good or fair quality. Further research is needed across all of the areas examined: effectiveness, satisfaction, and adverse effects.

Reverse Stability Kinetics of Meat Pigment Oxidation in Aqueous Extract from Fresh Beef.

PubMed

Frelka, John C; Phinney, David M; Wick, Macdonald P; Heldman, Dennis R

2017-12-01

The use of kinetic models is an evolving approach to describing quality changes in foods during processes, including storage. Previous studies indicate that the oxidation rate of myoglobin is accelerated under frozen storage conditions, a phenomenon termed reverse stability. The goal of this study was to develop a model for meat pigment oxidation to incorporate the phenomenon of reverse stability. In this investigation, the model system was an aqueous extract from beef which was stored under a range of temperatures, both unfrozen and frozen. The kinetic analysis showed that in unfrozen solutions, the temperature dependence of oxidation rate followed Arrhenius kinetics. However, under in frozen solutions the rate of oxidation increased with decreasing temperature until reaching a local maximum around -20 °C. The addition of NaCl to the model system increased oxidation rates at all temperatures, even above the initial freezing temperature. This observation suggests that this reaction is dependent on the ionic strength of the solution as well as temperature. The mechanism of this deviant kinetic behavior is not fully understood, but this study shows that the interplay of temperature and composition on the rate of oxidation of meat pigments is complicated and may involve multiple mechanisms. A better understanding of the kinetics of quality loss in a meat system allows for a re-examination of the current recommendations for frozen storage. The deviant kinetic behavior observed in this study indicates that the relationship between quality loss and temperature in a frozen food is not as simple as once thought. Product-specific recommendations could be implemented in the future that would allow for a decrease in energy consumption without a significant loss of quality. © 2017 Institute of Food Technologists®.

In-Vivo Imaging of Cell Migration Using Contrast Enhanced MRI and SVM Based Post-Processing.

PubMed

Weis, Christian; Hess, Andreas; Budinsky, Lubos; Fabry, Ben

2015-01-01

The migration of cells within a living organism can be observed with magnetic resonance imaging (MRI) in combination with iron oxide nanoparticles as an intracellular contrast agent. This method, however, suffers from low sensitivity and specificty. Here, we developed a quantitative non-invasive in-vivo cell localization method using contrast enhanced multiparametric MRI and support vector machines (SVM) based post-processing. Imaging phantoms consisting of agarose with compartments containing different concentrations of cancer cells labeled with iron oxide nanoparticles were used to train and evaluate the SVM for cell localization. From the magnitude and phase data acquired with a series of T2*-weighted gradient-echo scans at different echo-times, we extracted features that are characteristic for the presence of superparamagnetic nanoparticles, in particular hyper- and hypointensities, relaxation rates, short-range phase perturbations, and perturbation dynamics. High detection quality was achieved by SVM analysis of the multiparametric feature-space. The in-vivo applicability was validated in animal studies. The SVM detected the presence of iron oxide nanoparticles in the imaging phantoms with high specificity and sensitivity with a detection limit of 30 labeled cells per mm3, corresponding to 19 μM of iron oxide. As proof-of-concept, we applied the method to follow the migration of labeled cancer cells injected in rats. The combination of iron oxide labeled cells, multiparametric MRI and a SVM based post processing provides high spatial resolution, specificity, and sensitivity, and is therefore suitable for non-invasive in-vivo cell detection and cell migration studies over prolonged time periods.

High field FT-ICR mass spectrometry for molecular characterization of snow board from Moscow regions.

PubMed

Mazur, Dmitry M; Harir, Mourad; Schmitt-Kopplin, Philippe; Polyakova, Olga V; Lebedev, Albert T

2016-07-01

High field Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry analysis of eight snow samples from Moscow city allowed us to identify more than 2000 various elemental compositions corresponding to regional air pollutants. The hierarchical cluster analysis (HCA) of the data showed good concordance of three main groups of samples with the main wind directions. The North-West group (A1) is represented by several homologous CHOS series of aliphatic organic aerosols. They may form as a result of enhanced photochemical reactions including oxidation of hydrocarbons with sulfonations due to higher amount of SO2 emissions in the atmosphere in this region. Group A2, corresponding to the South-East part of Moscow, contains large amount of oxidized hydrocarbons of different sources that may form during oxidation in atmosphere. These hydrocarbons appear correlated to emissions from traffic, neighboring oil refinery, and power plants. Another family of compounds specific for this region involves CHNO substances formed during oxidation processes including NOx and NO3 radical since emissions of NOx are higher in this part of the city. Group A3 is rich in CHO type of compounds with high H/C and low O/C ratios, which is characteristic of oxidized hydrocarbon-like organic aerosol. CHNO types of compounds in A3 group are probably nitro derivatives of condensed hydrocarbons such as PAH. This non-targeted profiling revealed site specific distribution of pollutants and gives a chance to develop new strategies in air quality control and further studies of Moscow environment. Copyright © 2016 Elsevier B.V. All rights reserved.

“Transference Ratios” to Predict Total Oxidized Sulfur and Nitrogen Deposition – Part I, Monitoring Results

EPA Science Inventory

Use of model-predicted “transference ratios” is currently under consideration by the US EPA in the formulation of a Secondary National Ambient Air Quality Standard for oxidized nitrogen and oxidized sulfur. This term is an empirical parameter defined for oxidized sulfur (TS)as th...

Thiol oxidation by nitrosative stress: Cellular localization in human spermatozoa.

PubMed

Cabrillana, María E; Uribe, Pamela; Villegas, Juana V; Álvarez, Juan; Sánchez, Raúl; Fornés, Miguel W

2016-10-01

Peroxynitrite is a highly reactive nitrogen species and when it is generated at high levels it causes nitrosative stress, an important cause of impaired sperm function. High levels of peroxynitrite have been shown to correlate with decreased semen quality in infertile men. Thiol groups in sperm are mainly found in enzymes, antioxidant molecules, and structural proteins in the axoneme. Peroxynitrite primarily reacts with thiol groups of cysteine-containing proteins. Although it is well known that peroxynitrite oxidizes sulfhydryl groups in sperm, the subcellular localization of this oxidation remains unknown. The main objective of this study was to establish the subcellular localization of peroxynitrite-induced nitrosative stress in thiol groups and its relation to sperm motility in human spermatozoa. For this purpose, spermatozoa from healthy donors were exposed in vitro to 3-morpholinosydnonimine (SIN-1), a compound which generates peroxynitrite. In order to detect peroxynitrite and reduced thiol groups, the fluorescent probes, dihydrorhodamine 123 and monobromobimane (mBBr), were used respectively. Sperm viability was analyzed by propidium iodide staining. Peroxynitrite generation and thiol redox state were monitored by confocal microscopy whereas sperm viability was evaluated by flow cytometry. Sperm motility was analyzed by CASA using the ISAS(®) system. The results showed that exposure of human spermatozoa to peroxynitrite results in increased thiol oxidation which is mainly localized in the sperm head and principal piece regions. Thiol oxidation was associated with motility loss. The high susceptibility of thiol groups to peroxynitrite-induced oxidation could explain, at least in part, the negative effect of reactive nitrogen species on sperm motility. DHR: dihydrorhodamine 123; mBBr: monobromobimane ONOO(-): peroxynitrite RNS: reactive nitrogen species RFI: relative fluorescence intensity SIN-1: 3-morpholinosydnonimine CASA: Computer-Aided Sperm Analysis PARP: poli ADP ribose polimerasa VCL: curvilinear velocity VSL: straight-line velocity VAP: average path velocity PRDXs: peroxiredoxins ODF: outer dense fiber ODF1: outer dense fiber 1 PI: propidium iodide DMSO: dimethyl sulfoxide SD: standard deviation analysis of variance.

δ13C Analysis of Dissolved Organic Carbon in Eastern Canadian Coastal Waters

NASA Astrophysics Data System (ADS)

Gelinas, Y.; Barber, A.

2016-12-01

The application of carbon stable isotope analysis on dissolved organic carbon (δ13C-DOC) from natural seawater samples has been limited owing to the difficulty of such analysis, with order of magnitude differences between interfering ions and analyte concentrations. High temperature catalytic oxidation allows for the separation of interferences from the organic carbon by precipitation on quartz chips upstream from the oxidation catalyst. Unlike wet chemical oxidation, where salts inhibit the oxidation of organic matter to CO2 via side reactions between the salt anions and the persulfate oxidizing agent, high temperature combustion ensures complete organic matter oxidation in a stream of O2. Using a programmable chemical trap to switch carrier gasses from O2 to He, the OI 1030C combustion unit can be coupled to and IRMS, allowing for the analysis of low DOC content saline waters with relatively high throughput. The analytical limitations and large water volumes traditionally required for these types of analyses have prevented any large-scale δ13C-DOC studies. Here we present DOC concentrations and δ13C-DOC signatures for surface and bottom waters obtained along Canada's East Coast. Included in the study are samples from the Esquiman channel (between Newfoundland and Labrador), Lake Melville, the Saglek and Nachvak Fjords, the Hudson Strait and finally covering the salinity gradient across the Gulf of the St. Lawrence, the St. Lawrence Estuary and the Saguenay Fjord. Measured δ13C-DOC signatures ranged from predominantly marine values of -21.3 ± 0.6 ‰ (vs. VPDB) off the coast of Newfoundland to predominantly terrestrial signatures of -25.8 ± 0.1‰ in Lake Melville. Overall, proper blank subtraction using the isotope mass balance equation and four replicate injections are crucial for the collection of meaningful high quality δ13C-DOC signatures on natural abundance, seawater samples.

Characterization of Interface State in Silicon Carbide Metal Oxide Semiconductor Capacitors

NASA Astrophysics Data System (ADS)

Kao, Wei-Chieh

Silicon carbide (SiC) has always been considered as an excellent material for high temperature and high power devices. Since SiC is the only compound semiconductor whose native oxide is silicon dioxide (SiO2), it puts SiC in a unique position. Although SiC metal oxide semiconductor (MOS) technology has made significant progress in recent years, there are still a number of issues to be overcome before more commercial SiC devices can enter the market. The prevailing issues surrounding SiC MOSFET devices are the low channel mobility, the low quality of the oxide layer and the high interface state density at the SiC/SiO2 interface. Consequently, there is a need for research to be performed in order to have a better understanding of the factors causing the poor SiC/SiO2 interface properties. In this work, we investigated the generation lifetime in SiC materials by using the pulsed metal oxide semiconductor (MOS) capacitor method and measured the interface state density distribution at the SiC/SiO2 interface by using the conductance measurement and the high-low frequency capacitance technique. These measurement techniques have been performed on n-type and p-type SiC MOS capacitors. In the course of our investigation, we observed fast interface states at semiconductor-dielectric interfaces in SiC MOS capacitors that underwent three different interface passivation processes, such states were detected in the nitrided samples but not observed in PSG-passivated samples. This result indicate that the lack of fast states at PSG-passivated interface is one of the main reasons for higher channel mobility in PSG MOSFETs. In addition, the effect of mobile ions in the oxide on the response time of interface states has been investigated. In the last chapter we propose additional methods of investigation that can help elucidate the origin of the particular interface states, enabling a more complete understanding of the SiC/SiO2 material system.

Hybrid Molecular Beam Epitaxy for High Quality Strontium Titanate

NASA Astrophysics Data System (ADS)

Jalan, Bharat

2011-12-01

Advancement in thin film growth techniques drives new physics and technologies. Thin film growth approaches and characterization techniques have become more crucial than ever to design and evaluate many emerging materials systems, such as complex oxides. Complex oxides with the perovskite and related structures are fundamentally different from conventional semiconductors and exhibit much richer phenomena as diverse as ferroelectricity, superconductivity, and strongly-correlated Mott-Hubbard-type insulator characteristics. The structural quality of oxide films grown by molecular beam epitaxy (MBE) now matches that of epitaxial semiconductors. Stoichiometry control, however, remains a major challenge. The presence of large (˜tens of ppm) amounts of point defects and impurities, which are commonly present in thin films, has often made the realization and interpretation of intrinsic phenomena difficult. In this dissertation we first describe our work in the development of a hybrid MBE approach for the growth of high quality insulating SrTiO 3 films. The approach uses a combination of solid and metal-organic sources to supply the metals. Films grow in layer-by-layer and step-flow growth modes, with atomically smooth surfaces and an excellent structural quality that is only limited by those of the substrates. A major as- pect of this MBE technique is that it provides a route to stoichiometric SrTiO3. This is achieved by growing films within a "MBE growth window", in which the stoichiome- try is self-regulating, independent of the precise metal flux ratios. Despite the use of a chemical precursor that supply Ti, the carbon incorporation in the films remains below or in the low ppm range. This was achieved by growing films at relatively high temper- atures. We will discuss the transport properties of MBE grown SrTiO3 film. We show that excellent stoichiometry control and low intrinsic defect concentrations, afforded by MBE, allow for the high electron mobility in n-doped SrTiO 3 films, exceeding that of bulk single crystals. In addition, we demonstrate that modification of the band-structure and removal of domains etc. using uniaxial compressive stress can lead to an additional enhancement of low-temperature electron mobility by 300%, up to 128,000 cm2/Vs, with no obvious mobility saturation. Finally, we discuss the nature of the two-dimensional electron gas in delta-doped SrTiO3 films by analyzing Shubnikov-de Haas oscillations. Despite the inherent com- plexity of a sub-band that is derived from four d-band states near the conduction band minimum, we show that the quantum oscillations can be modeled quantitatively. We present the room temperature thermoelectric properties of uniformly doped and delta-doped SrTiO3 films, with the goal to explore these high quality films not only as a potential thermoelectric but also to understand electronic structure using electrical and thermal transport.

Structures, Properties and Defects of SrTiO3/GaAs Hetero-interfaces

NASA Astrophysics Data System (ADS)

Hong, Liang; Bhatnagar, Kunal; Droopad, Ravi; Öğüt, Serdar; Klie, Robert

SrTiO3 thin film can be epitaxially grown on GaAs substrate and used as a platform for growing other oxides to create functional metal-oxide-semiconductor devices, where a high-quality SrTiO3/GaAs interface is essential. We studied the structural and electronic properties of SrTiO3/GaAs hetero-interfaces at atomic level using scanning transmission electron microscopy and first-principles calculations. Our results suggest the preferred termination of GaAs (001) is significantly dependent on the oxygen concentration in the first oxide layer. The favorable interface structure is characterized as oxygen-deficient SrO in contact with arsenic and is observed in both experiment and simulation. The electronic properties are calculated and found to be tunable by interfacial defects such as oxygen, gallium and arsenic vacancies. This work was supported by the National Science Foundation (Grant No. DMR-1408427). This work made use of instruments in the Electron Microscopy Service and the High Performance Computing Clusters at University of Illinois at Chicago.

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

PubMed

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.

In Situ deposition of YBCO high-T(sub c) superconducting thin films by MOCVD and PE-MOCVD

NASA Technical Reports Server (NTRS)

Zhao, J.; Noh, D. W.; Chern, C.; Li, Y. Q.; Norris, P.; Gallois, B.; Kear, B.

1990-01-01

Metalorganic Chemical Vapor Deposition (MOCVD) offers the advantages of a high degree of compositional control, adaptability for large scale production, and the potential for low temperature fabrication. The capability of operating at high oxygen partial pressure is particularly suitable for in situ formation of high temperature superconducting (HTSC) films. Yttrium barium copper oxide (YBCO) thin films having a sharp zero-resistance transition with T( sub c) greater than 90 K and Jc approx. 10 to the 4th power A on YSZ have been prepared, in situ, at a substrate temperature of about 800 C. Moreover, the ability to form oxide films at low temperature is very desirable for device applications of HTSC materials. Such a process would permit the deposition of high quality HTSC films with a smooth surface on a variety of substrates. Highly c-axis oriented, dense, scratch resistant, superconducting YBCO thin films with mirror-like surfaces have been prepared, in situ, at a reduced substrate temperature as low as 570 C by a remote microwave-plasma enhanced metalorganic chemical vapor deposition (PE-MOCVD) process. Nitrous oxide was used as a reactant gas to generate active oxidizing species. This process, for the first time, allows the formation of YBCO thin films with the orthorhombic superconducting phase in the as-deposited state. The as-deposited films grown by PE-MOCVD show attainment of zero resistance at 72 K with a transition width of about 5 K. MOCVD was carried out in a commercial production scale reactor with the capability of uniform deposition over 100 sq cm per growth run. Preliminary results indicate that PE-MOCVD is a very attractive thin film deposition process for superconducting device technology.

In-situ deposition of YBCO high-Tc superconducting thin films by MOCVD and PE-MOCVD

NASA Technical Reports Server (NTRS)

Zhao, J.; Noh, D. W.; Chern, C.; Li, Y. Q.; Norris, P. E.; Kear, B.; Gallois, B.

1991-01-01

Metal-Organic Chemical Vapor Deposition (MOCVD) offers the advantages of a high degree of compositional control, adaptability for large scale production, and the potential for low temperature fabrication. The capability of operating at high oxygen partial pressure is particularly suitable for in situ formation of high temperature superconducting (HTSC) films. Yttrium barium copper oxide (YBCO) thin films having a sharp zero-resistance transition with T(sub c) greater than 90 K and J(sub c) of approximately 10(exp 4) A on YSZ have been prepared, in situ, at a substrate temperature of about 800 C. Moreover, the ability to form oxide films at low temperature is very desirable for device applications of HTSC materials. Such a process would permit the deposition of high quality HTSC films with a smooth surface on a variety of substrates. Highly c-axis oriented, dense, scratch resistant, superconducting YBCO thin films with mirror-like surfaces have been prepared, in situ, at a reduced substrate temperature as low as 570 C by a remote microwave-plasma enhanced metal-organic chemical vapor deposition (PE-MOCVD) process. Nitrous oxide was used as a reactant gas to generate active oxidizing species. This process, for the first time, allows the formation of YBCO thin films with the orthorhombic superconducting phase in the as-deposited state. The as-deposited films grown by PE-MOCVD show attainment of zero resistance at 72 K with a transition width of about 5 K. MOCVD was carried out in a commercial production scale reactor with the capability of uniform deposition over 100 sq cm per growth run. Preliminary results indicate that PE-MOCVD is a very attractive thin film deposition process for superconducting device technology.

Inert-Gas Diffuser For Plasma Or Arc Welding

NASA Technical Reports Server (NTRS)

Gilbert, Jeffrey L.; Spencer, Carl N.; Hosking, Timothy J.

1994-01-01

Inert-gas diffuser provides protective gas cover for weld bead as it cools. Follows welding torch, maintaining continuous flow of argon over newly formed joint and prevents it from oxidizing. Helps to ensure welds of consistently high quality. Devised for plasma arc keyhole welding of plates of 0.25-in. or greater thickness, also used in tungsten/inert-gas and other plasma or arc welding processes.

Corrosion and corrosion prevention in gas turbines

NASA Technical Reports Server (NTRS)

Mom, A. J. A.; Kolkman, H. J.

1985-01-01

The conditions governing the corrosion behavior in gas turbines are surveyed. Factors such as temperature, relative humidity, the presence of sulfur and nitrogen dioxide, and fuel quality are discussed. Electromechanical corrosion at relatively low temperature in compressors; oxidation; and hot corrosion (sulfidation) at high temperature in turbines are considered. Corrosion prevention by washing and rinsing, fueld additives, and corrosion resistant materials and coatings are reviewed.

Draft Genome Sequence of Telmatospirillum siberiense 26-4b1, an Acidotolerant Peatland Alphaproteobacterium Potentially Involved in Sulfur Cycling

PubMed Central

Schreck, Katharina; Herbold, Craig W.; Daims, Holger; Wagner, Michael; Loy, Alexander

2018-01-01

ABSTRACT The facultative anaerobic chemoorganoheterotrophic alphaproteobacterium Telmatospirillum siberiense 26-4b1 was isolated from a Siberian peatland. We report here a 6.20-Mbp near-complete high-quality draft genome sequence of T. siberiense that reveals expected and novel metabolic potential for the genus Telmatospirillum, including genes for sulfur oxidation. PMID:29371357

Increasing the reliability and quality of important cast products made of chemically active metals and alloys

NASA Astrophysics Data System (ADS)

Varfolomeev, M. S.; Moiseev, V. S.; Shcherbakova, G. I.

2017-01-01

A technology is developed to produce highly thermoresistant ceramic monoxide corundum molds using investment casting and an aluminum-organic binder. This technology is a promising trend in creating ceramic molds for precision complex-shape casting of important ingots made of high-alloy steels, high-temperature and titanium alloys, and refractory metals. The use of the casting molds that have a high thermal and chemical resistance to chemically active metals and alloys under high-temperature casting minimizes the physicochemical interaction and substantially decreases the depth of the hard-to-remove metal oxide layer on important products, which increases their service properties.

Oxynitride glass fibers

NASA Technical Reports Server (NTRS)

Patel, Parimal J.; Messier, Donald R.; Rich, R. E.

1991-01-01

Research at the Army Materials Technology Laboratory (AMTL) and elsewhere has shown that many glass properties including elastic modulus, hardness, and corrosion resistance are improved markedly by the substitution of nitrogen for oxygen in the glass structure. Oxynitride glasses, therefore, offer exciting opportunities for making high modulus, high strength fibers. Processes for making oxynitride glasses and fibers of glass compositions similar to commercial oxide glasses, but with considerable enhanced properties, are discussed. We have made glasses with elastic moduli as high as 140 GPa and fibers with moduli of 120 GPa and tensile strengths up to 2900 MPa. AMTL holds a U.S. patent on oxynitride glass fibers, and this presentation discusses a unique process for drawing small diameter oxynitride glass fibers at high drawing rates. Fibers are drawn through a nozzle from molten glass in a molybdenum crucible at 1550 C. The crucible is situated in a furnace chamber in flowing nitrogen, and the fiber is wound in air outside of the chamber, making the process straightforward and commercially feasible. Strengths were considerably improved by improving glass quality to minimize internal defects. Though the fiber strengths were comparable with oxide fibers, work is currently in progress to further improve the elastic modulus and strength of fibers. The high elastic modulus of oxynitride glasses indicate their potential for making fibers with tensile strengths surpassing any oxide glass fibers, and we hope to realize that potential in the near future.

Application of guar-xanthan gum mixture as a partial fat replacer in meat emulsions.

PubMed

Rather, Sajad A; Masoodi, F A; Akhter, Rehana; Rather, Jahangir A; Gani, Adil; Wani, S M; Malik, A H

2016-06-01

The physicochemical, oxidative, texture and microstructure properties were evaluated for low fat meat emulsions containing varying levels of guar/xanthan gum mixture (1:1 ratio) as a fat substitute. Partial replacement of fat with guar/xanthan gum resulted in higher emulsion stability and cooking yield but lower penetration force. Proximate composition revealed that high fat control had significantly higher fat and lower moisture content due to the difference in basic formulation. Colour evaluation revealed that low fat formulations containing gum mixture had significantly lower lightness and higher yellowness values than high fat control formulation. However non-significant difference was observed in redness values between low fat formulations and the high fat control. The pH values of the low fat formulations containing gum mixture were lower than the control formulations (T0 and TC). The MetMb% of the high fat emulsion formulation was higher than low fat formulations. The significant increase of TBARS value, protein carbonyl groups and loss of protein sulphydryl groups in high fat formulation reflect the more oxidative degradation of lipids and muscle proteins during the preparation of meat emulsion than low fat formulations. The SEM showed a porous matrix in the treatments containing gum mixture. Thus, the guar/xanthan gum mixture improved the physicochemical and oxidative quality of low fat meat emulsions than the control formulations.

Chemical, Rheological and Nutritional Characteristics of Sesame and Olive Oils Blended with Linseed Oil.

PubMed

Hashempour-Baltork, Fataneh; Torbati, Mohammadali; Azadmard-Damirchi, Sodeif; Peter Savage, Geoffrey

2018-03-01

Purpose: Nutritional quality and oxidation stability are two main factors in the evaluation of edible oils. Oils in their pure form do not have an ideal fatty acid composition or suitable oxidative stability during processing or storage. Methods: This study was designed to evaluate the chemical, nutritional and rheological properties of oil mixtures in three ratios of olive: sesame: linseed, 65:30:5; 60:30:10 and 55:30:15. Acidity value, peroxide value, rancimat test, fatty acid profile, nutritional indexes and rheological properties of the oil blends were determined. The nutritional quality was determined by indexes, including the atherogenic and thrombogenic indexs; the ratios of hypocholesterolemic: hypercholesterolemic; poly unsaturated fatty acid: saturated fatty acid and the ω 6 :ω 3 . Results: The results indicated that blending of other vegetable oils with linseed oil could balance ω 6 :ω 3 . Results showed that formulated oils had a good balance of oxidation stability and nutritional properties as well. Rheological data showed that these oil blends followed Newtonian behavior at 4°C and 25°C. Conclusion: According to the results, addition of linseed oil to vegetable oils containing high levels of bioactive compounds was a simple and economic practice to obtain a functional oil with good nutritional and stability properties.

Bleeding Efficiency, Microbiological Quality and Oxidative Stability of Meat from Goats Subjected to Slaughter without Stunning in Comparison with Different Methods of Pre-Slaughter Electrical Stunning

PubMed Central

Sabow, Azad Behnan; Zulkifli, Idrus; Goh, Yong Meng; Ab Kadir, Mohd Zainal Abidin; Kaka, Ubedullah; Imlan, Jurhamid Columbres; Abubakar, Ahmed Abubakar; Adeyemi, Kazeem Dauda; Sazili, Awis Qurni

2016-01-01

The influence of pre-slaughter electrical stunning techniques and slaughter without stunning on bleeding efficiency and shelf life of chevon during a 14 d postmortem aging were assessed. Thirty two Boer crossbred bucks were randomly assigned to four slaughtering techniques viz slaughter without stunning (SWS), low frequency head-only electrical stunning (LFHO; 1 A for 3 s at a frequency of 50 Hz), low frequency head-to-back electrical stunning (LFHB; 1 A for 3 s at a frequency of 50 Hz) and high frequency head-to-back electrical stunning (HFHB; 1 A for 3 s at a frequency of 850 Hz). The SWS, LFHO and HFHB goats had higher (p<0.05) blood loss and lower residual hemoglobin in muscle compared to LFHB. The LFHB meat had higher (p<0.05) TBARS value than other treatments on d 7 and 14 d postmortem. Slaughtering methods had no effect on protein oxidation. Higher bacterial counts were observed in LFHB meat compared to those from SWS, LFHO and HFHB after 3 d postmortem. Results indicate that the low bleed-out in LFHB lowered the lipid oxidative stability and microbiological quality of chevon during aging. PMID:27035716

Bleeding Efficiency, Microbiological Quality and Oxidative Stability of Meat from Goats Subjected to Slaughter without Stunning in Comparison with Different Methods of Pre-Slaughter Electrical Stunning.

PubMed

Sabow, Azad Behnan; Zulkifli, Idrus; Goh, Yong Meng; Ab Kadir, Mohd Zainal Abidin; Kaka, Ubedullah; Imlan, Jurhamid Columbres; Abubakar, Ahmed Abubakar; Adeyemi, Kazeem Dauda; Sazili, Awis Qurni

2016-01-01

The influence of pre-slaughter electrical stunning techniques and slaughter without stunning on bleeding efficiency and shelf life of chevon during a 14 d postmortem aging were assessed. Thirty two Boer crossbred bucks were randomly assigned to four slaughtering techniques viz slaughter without stunning (SWS), low frequency head-only electrical stunning (LFHO; 1 A for 3 s at a frequency of 50 Hz), low frequency head-to-back electrical stunning (LFHB; 1 A for 3 s at a frequency of 50 Hz) and high frequency head-to-back electrical stunning (HFHB; 1 A for 3 s at a frequency of 850 Hz). The SWS, LFHO and HFHB goats had higher (p<0.05) blood loss and lower residual hemoglobin in muscle compared to LFHB. The LFHB meat had higher (p<0.05) TBARS value than other treatments on d 7 and 14 d postmortem. Slaughtering methods had no effect on protein oxidation. Higher bacterial counts were observed in LFHB meat compared to those from SWS, LFHO and HFHB after 3 d postmortem. Results indicate that the low bleed-out in LFHB lowered the lipid oxidative stability and microbiological quality of chevon during aging.

Relationship between the UPLC-Q-TOF-MS fingerprinted constituents from Daphne genkwa and their anti-inflammatory, anti-oxidant activities.

PubMed

Du, Wen-Juan; Ji, Jun; Wang, Ling; Lan, Xin-Yi; Li, Jia; Lei, Jun-Qiu; He, Xin; Zhang, Chun-Feng; Huang, Wen-Zhe; Wang, Zhen-Zhong; Xiao, Wei; Wang, Chong-Zhi; Yuan, Chun-Su

2017-12-01

Daphne genkwa Sieb.et Zucc. is a well-known medicinal plant. This study was designed to apply the ultra-high performance liquid chromatography system to establish a quality control method for D. genkwa. Data revealed that there were 15 common peaks in 10 batches of D. genkwa Sieb. Et Zucc. (Thymelaeaceae) from different provinces of China. On this basis, the fingerprint chromatogram was established to provide references for quality control. Afterwards, the chemical constitutions of these common peaks were analyzed using the UPLC-Q-TOF-MS system and nine of them were identified. In addition, LPS-stimulated RAW264.7 murine macrophages and DPPH assay were used to study the anti-inflammatory and anti-oxidation effects of D. genkwa. Then the fingerprint-efficacy relationships between UPLC fingerprints and pharmacodynamic data were studied with canonical correlation analysis. Analysis results indicated that the anti-inflammatory and anti-oxidation effects differed among the 10 D. genkwa samples owing to their inherent differences of chemical compositions. Taken together, this research established a fingerprint-efficacy relationship model of D. genkwa plant by combining the UPLC analytic technique and pharmacological research, which provided references for the detection of the principal components of traditional Chinese medicine on bioactivity. Copyright © 2017 John Wiley & Sons, Ltd.

Operation of staged membrane oxidation reactor systems

DOEpatents

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.

Effect of dietary plant extract on meat quality and sensory parameters of meat from Equidae.

PubMed

Rossi, Raffaella; Ratti, Sabrina; Pastorelli, Grazia; Maghin, Federica; Martemucci, Giovanni; Casamassima, Donato; D'Alessandro, Angela Gabriella; Corino, Carlo

2017-11-01

Plant extracts as Lippia spp. have been proven antioxidant properties. Recent studies have been shown that dietary supplementation with plant extracts is able to enhance meat quality parameters. Studies regarding meat quality in Equidae are limited. The effect of dietary plant extract (PE), containing verbascoside, on meat quality, oxidative stability and sensory parameters of Longissimus Lumborum (LL) muscle in Equidae was studied. Dietary treatment did not affect (P > 0.05) pH, colour indices and chemical parameters of muscle in both donkey and horse. Dietary PE improved (P < 0.01) oxidative stability in donkey muscle during refrigerated storage. Sensory characteristics of LL muscle were positively affected (P < 0.05) by dietary PE in both donkey and horse. In particular, colour, taste and texture were enhanced in LL muscle from animals fed PE. Oxidative stability was lower (P < 0.05) in LL muscle of horse than that of donkey. Dietary plant extract, containing verbascoside, can be considered as a natural source of antioxidants, and is also able to improve oxidative stability of donkey meat and to affect the sensory attributes of Equidae meat. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Fast in-situ measurements of glyoxal (CHOCHO) and nitrous acid (HONO) in northern Chinese plane during CAREBEIJING - NCP2014

NASA Astrophysics Data System (ADS)

Min, K. E.; Dube, W. P.; Washenfelder, R. A.; Langford, A. O.; Brown, S. S.; Broch, S.; Fuchs, H.; Gomm, S.; Hofzumahaus, A.; Holland, F.; Hu, M.; Huey, L. G.; Kubik, K.; Li, X.; Liu, X.; Lu, K.; Rohrer, F.; Shao, M.; Sjostedt, S. J.; Tan, Z.; Zhu, T.; Wahner, A.; Wang, B.; Wang, M.; Wang, Y.; Zeng, L.; Zhang, Y.

2014-12-01

The Northern China Plain has experienced visibility degradation and detrimental health impacts due to aerosol and photochemical pollution. To examine these air quality issues, CAREBEIJING-NCP2014 (Care Beijing - Northern China Plain 2014) was held in WangDu, Hebei province, China from 6 June to 15 July 2014. We deployed our newly developed instrument, ACES (Airborne Cavity Enhanced Spectrometer), for high time resolution in-situ measurement of glyoxal (CHOCHO), nitrous acid (HONO) and other trace gases (NO2, H2O) to investigate mechanisms of oxidation processes and secondary organic aerosol (SOA) formation. The in situ measurements of CHOCHO provide observational constraints on secondary organic aerosol formation and oxidation processes, since this molecule has been proposed to play a crucial role in forming aerosol due to its high water solubility, isomerization, and abundant production from the oxidation of many different volatile organic compounds (VOCs). A box model analysis incorporating secondary glyoxal sources from VOC oxidation and sinks to OH reaction, photolysis and heterogeneous uptake will be used to determine a budget and potential for SOA formation. This work was supported by the National Natural Science Foundation of China (21190052), the Strategic Priority Research Program of the Chinese Academy of Sciences (XDB05010500) and the U.S. National Science Foundation Atmospheric (AGS-1405805).

Tailoring recombinant protein quality by rational media design.

PubMed

Brühlmann, David; Jordan, Martin; Hemberger, Jürgen; Sauer, Markus; Stettler, Matthieu; Broly, Hervé

2015-01-01

Clinical efficacy and safety of recombinant proteins are closely associated with their structural characteristics. The major quality attributes comprise glycosylation, charge variants (oxidation, deamidation, and C- & N-terminal modifications), aggregates, low-molecular-weight species (LMW), and misincorporation of amino acids in the protein backbone. Cell culture media design has a great potential to modulate these quality attributes due to the vital role of medium in mammalian cell culture. The purpose of this review is to provide an overview of the way both classical cell culture medium components and novel supplements affect the quality attributes of recombinant therapeutic proteins expressed in mammalian hosts, allowing rational and high-throughput optimization of mammalian cell culture media. A selection of specific and/or potent inhibitors and activators of oligosaccharide processing as well as components affecting multiple quality attributes are presented. Extensive research efforts in this field show the feasibility of quality engineering through media design, allowing to significantly modulate the protein function. © 2015 American Institute of Chemical Engineers.

Different Polar Metabolites and Protein Profiles between High- and Low-Quality Japanese Ginjo Sake

PubMed Central

Takahashi, Kei; Kohno, Hiromi

2016-01-01

Japanese ginjo sake is a premium refined sake characterized by a pleasant fruity apple-like flavor and a sophisticated taste. Because of technical difficulties inherent in brewing ginjo sake, off-flavors sometimes occur. However, the metabolites responsible for off-flavors as well as those present or absent in higher quality ginjo sake remain uncertain. Here, the relationship between 202 polar chemical compounds in sake identified using capillary electrophoresis coupled with time-of-flight mass spectrometry and its organoleptic properties, such as quality and off-flavor, was examined. First, we found that some off-flavored sakes contained higher total amounts of metabolites than other sake samples. The results also identified that levels of 2-oxoglutaric acid and fumaric acid, metabolites in the tricarboxylic acid cycle, were highly but oppositely correlated with ginjo sake quality. Similarly, pyridoxine and pyridoxamine, co-enzymes for amino transferase, were also highly but oppositely correlated with ginjo sake quality. Additionally, pyruvic acid levels were associated with good quality as well. Compounds involved in the methionine salvage cycle, oxidative glutathione derivatives, and amino acid catabolites were correlated with low quality. Among off-flavors, an inharmonious bitter taste appeared attributable to polyamines. Furthermore, protein analysis displayed that a diversity of protein components and yeast protein (triosephosphate isomerase, TPI) leakage was linked to the overall metabolite intensity in ginjo sake. This research provides insight into the relationship between sake components and organoleptic properties. PMID:26939054

Growth and Photovoltaic Properties of High-Quality GaAs Nanowires Prepared by the Two-Source CVD Method.

PubMed

Wang, Ying; Yang, Zaixing; Wu, Xiaofeng; Han, Ning; Liu, Hanyu; Wang, Shuobo; Li, Jun; Tse, WaiMan; Yip, SenPo; Chen, Yunfa; Ho, Johnny C

2016-12-01

Growing high-quality and low-cost GaAs nanowires (NWs) as well as fabricating high-performance NW solar cells by facile means is an important development towards the cost-effective next-generation photovoltaics. In this work, highly crystalline, dense, and long GaAs NWs are successfully synthesized using a two-source method on non-crystalline SiO2 substrates by a simple solid-source chemical vapor deposition method. The high V/III ratio and precursor concentration enabled by this two-source configuration can significantly benefit the NW growth and suppress the crystal defect formation as compared with the conventional one-source system. Since less NW crystal defects would contribute fewer electrons being trapped by the surface oxides, the p-type conductivity is then greatly enhanced as revealed by the electrical characterization of fabricated NW devices. Furthermore, the individual single NW and high-density NW parallel arrays achieved by contact printing can be effectively fabricated into Schottky barrier solar cells simply by employing asymmetric Ni-Al contacts, along with an open circuit voltage of ~0.3 V. All these results indicate the technological promise of these high-quality two-source grown GaAs NWs, especially for the realization of facile Schottky solar cells utilizing the asymmetric Ni-Al contact.

The investigation on the structure, fabrication and applications of graphene

NASA Astrophysics Data System (ADS)

Du, Donghe

By investigating the structure of graphene oxide (GO), the long-wavelength photoluminescence of GO is evidenced to be originated from the excimer formation between GO basal plane and oxidative debris (ODs) attached on the GO sheets. The thermally unstable ODs would induce micro-explosion of GO upon heating. A novel method is developed to supress the explosion and achieve simultaneous thermal reduction and nitrogen doping of graphene oxide in air. The high quality N-doped graphene demonstrate excellent electrocatalytic property in oxygen reduction reaction. Furthermore, an electronic textile material is fabricated by coating chemically reduced GO on a piece of non-woven fabric (GNWF). GNWF can be applied as wearable sensors to detect physiological signals of human body. This research work deepens the understanding on the structure and property of graphene based materials and provides a cost-effective fabrication method for large scale production of graphene, and hence facilitates the commercialization of graphene.

Mechanism of Arsenic Adsorption Using Wheat Biomass -- a spectroscopic study

NASA Astrophysics Data System (ADS)

Calvo, Oscar; Manciu, Felicia; Maldonado, Josefina; Gardea-Torresdey, Jorge

2006-10-01

Arsenic is a trace element that is toxic to animals, humans included. Since the current Environmental Protection Agency guidelines regarding water quality standards indicate that arsenic concentrations in excess of 50 ppb are hazardous to welfare of humans, the search for new water remediation methods or improvements of previous methods have been a focus in environmental technology. Investigations of arsenic uptake have used wide range of sorbents including iron oxides and oxyhydroxides, for which it have been proved that arsenic shows high affinity. In this study, we used far-infrared spectroscopy to examine the arsenic reduction using biomaterials. pH dependence analysis by FTIR demonstrates the sorption of iron oxides and oxyhydroxides by the wheat biomass. The splitting of 350 cm-1 amorphous iron oxide vibrations is a direct proof of the arsenic uptake. In addition, there is evidence of sorption of arsenic at sulfhydryl group of cysteine existent in wheat.

Performance of diatomite/iron oxide modified nonwoven membrane used in membrane bioreactor process for wastewater reclamation.

PubMed

He, Yueling; Zhang, Wenqi; Rao, Pinhua; Jin, Peng

2014-01-01

This study describes an approach for surface modification of a nonwoven membrane by diatomite/iron oxide to examine its filterability. Analysis results showed that nonwoven hydrophilicity is enhanced. Static contact angle decreases dramatically from 122.66° to 39.33°. Scanning electron micrograph images show that diatomite/iron oxide is attached on nonwoven fiber. X-ray diffraction analysis further proves that the compound is mostly magnetite. Fourier transformed infrared spectra results reveal that two new absorption peaks might be attributed to Si-O and Fe-O, respectively. Modified and original membranes were used in double nonwoven membrane bioreactors (MBRs) for synthetic wastewater treatment. High critical flux, long filtration time, slow trans-membrane pressure rise and stable sludge volume index confirmed the advantages of modified nonwoven. Comparing with original nonwoven, similar effluent qualities are achieved, meeting the requirements for wastewater reclamation.

Antidepressant Flavonoids and Their Relationship with Oxidative Stress

PubMed Central

Hritcu, Lucian; Ionita, Radu; Postu, Paula Alexandra; Gupta, Girish Kumar; Turkez, Hasan; Lima, Tamires Cardoso; Carvalho, Caroline Uchôa Souza

2017-01-01

Depression is a serious disorder that affects hundreds of millions of people around the world and causes poor quality of life, problem behaviors, and limitations in activities of daily living. Therefore, the search for new therapeutic options is of high interest and growth. Research on the relationship between depression and oxidative stress has shown important biochemical aspects in the development of this disease. Flavonoids are a class of natural products that exhibit several pharmacological properties, including antidepressant-like activity, and affects various physiological and biochemical functions in the body. Studies show the clinical potential of antioxidant flavonoids in treating depressive disorders and strongly suggest that these natural products are interesting prototype compounds in the study of new antidepressant drugs. So, this review will summarize the chemical and pharmacological perspectives related to the discovery of flavonoids with antidepressant activity. The mechanisms of action of these compounds are also discussed, including their actions on oxidative stress relating to depression. PMID:29410733

Development & characterization of alumina coating by atmospheric plasma spraying

NASA Astrophysics Data System (ADS)

Sebastian, Jobin; Scaria, Abyson; Kurian, Don George

2018-03-01

Ceramic coatings are applied on metals to prevent them from oxidation and corrosion at room as well as elevated temperatures. The service environment, mechanisms of protection, chemical and mechanical compatibility, application method, control of coating quality and ability of the coating to be repaired are the factors that need to be considered while selecting the required coating. The coatings based on oxide materials provides high degree of thermal insulation and protection against oxidation at high temperatures for the underlying substrate materials. These coatings are usually applied by the flame or plasma spraying methods. The surface cleanliness needs to be ensured before spraying. Abrasive blasting can be used to provide the required surface roughness for good adhesion between the substrate and the coating. A pre bond coat like Nickel Chromium can be applied on to the substrate material before spraying the oxide coating to avoid chances of poor adhesion between the oxide coating and the metallic substrate. Plasma spraying produces oxide coatings of greater density, higher hardness, and smooth surface finish than that of the flame spraying process Inert gas is often used for generation of plasma gas so as to avoid the oxidation of the substrate material. The work focuses to develop, characterize and optimize the parameters used in Al2O3 coating on transition stainless steel substrate material for minimizing the wear rate and maximizing the leak tightness using plasma spray process. The experiment is designed using Taguchi’s L9 orthogonal array. The parameters that are to be optimized are plasma voltage, spraying distance and the cooling jet pressure. The characterization techniques includes micro-hardness and porosity tests followed by Grey relational analysis of the results.

Microstructure, microbial profile and quality characteristics of high-pressure-treated chicken nuggets.

PubMed

Devatkal, Suresh; Anurag, Rahul; Jaganath, Bindu; Rao, Srinivasa

2015-10-01

High-pressure processing (300 MPa for 5 min) as a non-thermal post-processing intervention was employed to improve the shelf life and qualities of cooked refrigerated chicken nuggets. Pomegranate peel extract (1%) was also used as a source of natural antioxidant and antimicrobial in chicken nuggets. Microstructure, microbial profile, instrumental colour, texture profile and lipid oxidation were evaluated. High-pressure treatment and pomegranate peel extract did not influence significantly the colour and textural properties of cooked chicken nuggets. Thiobarbituric acid reactive substance values significantly (p < 0.05) increased in pressure-treated nuggets. Microstructural studies revealed shrinkage in the structure and loosening of the dense network of meat emulsion due to high-pressure treatment. Pressure treatment resulted in a reduction of 2-3.0 log10 cfu/g in total plate count and Enterobacteriaceae count. Molecular characterization studies revealed that Enterobacter amnigenus and Enterobacter sp. in control and Bacillus licheniformis, Enterococcus gallinarum and Acinetobacter baumannii in high-pressure-treated chicken nuggets were the major spoilage bacteria. © The Author(s) 2014.

The effects of three different exercise modalities on markers of male reproduction in healthy subjects: a randomized controlled trial.

PubMed

Hajizadeh Maleki, Behzad; Tartibian, Bakhtyar; Chehrazi, Mohammad

2017-02-01

The aim of this study was to investigate the effects of moderate-intensity continuous training (MICT), high-intensity continuous training (HICT) and high-intensity interval training (HIIT) on markers of male reproduction including seminal markers of oxidative stress and inflammation as well as semen quality and sperm DNA integrity in healthy human subjects. A total of 397 healthy male volunteers were screened and 280 were randomly assigned to one of the MICT (n = 70), HICT (n = 70), HIIT (n = 70) and non-exercise (NON-EX, n = 70) groups. Subjects had inflammatory markers (IL-1β, IL-6, IL-8 and TNF-α), oxidants (ROS, MDA and 8-isoprostane), antioxidants (SOD, catalase and TAC), semen parameters and sperm DNA damage measured at baseline (T 1 ), the end of week 12 (T 2 ), the end of week 24 (T 3 ), and 7 (T 4 ) and 30 days (T 5 ) after training. Chronic MICT, HICT and HIIT attenuated seminal markers of oxidative stress and inflammation with different kinetics for the three types of exercise (P < 0.05), and these changes were correlated with favorable improvements in semen quality parameters and sperm DNA integrity (P < 0.05). MICT was superior to HICT and HIIT in the improvements of markers of male reproductive function (P < 0.05). In conclusion, different exercise modalities favorably affect markers of male reproduction with different kinetics, suggesting intensity-, duration- and type-dependent adaptations to exercise training in healthy human subjects. © 2017 Society for Reproduction and Fertility.

Enhanced graphene oxide membranes and methods for making same

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shin, Yongsoon; Gotthold, David W.; Fifield, Leonard S.

A method for making a graphene oxide membrane and a resulting free-standing graphene oxide membrane that provides desired qualities of water permeability and selectivity at larger sizes, thinner cross sections, and with increased ruggedness as compared to existing membranes and processes.

Air Quality Criteria for Ozone and Other Photochemical Oxidants (1978)

EPA Science Inventory

This document consolidates and assesses current knowledge regarding the origin of ozone and other photochemical oxidants and discusses their effect on health, vegetation, certain ecosystems, and materials. This document summarizes current data on the effects of oxidant/ozone in t...

Switchable and tunable film bulk acoustic resonator fabricated using barium strontium titanate active layer and Ta{sub 2}O{sub 5}/SiO{sub 2} acoustic reflector

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sbrockey, N. M., E-mail: sbrockey@structuredmaterials.com; Tompa, G. S.; Kalkur, T. S.

2016-08-01

A solidly mounted acoustic resonator was fabricated using a Ba{sub 0.60}Sr{sub 0.40}TiO{sub 3} (BST) film deposited by metal organic chemical vapor deposition. The device was acoustically isolated from the substrate using a Bragg reflector consisting of three pairs of Ta{sub 2}O{sub 5}/SiO{sub 2} layers deposited by chemical solution deposition. Transmission electron microscopy verified that the Bragg reflector was not affected by the high temperatures and oxidizing conditions necessary to process high quality BST films. Electrical characterization of the resonator demonstrated a quality factor (Q) of 320 and an electromechanical coupling coefficient (K{sub t}{sup 2}) of 7.0% at 11 V.

40 CFR 52.2780 - Control strategy for sulfur oxides.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 4 2011-07-01 2011-07-01 false Control strategy for sulfur oxides. 52... strategy for sulfur oxides. (a) The requirements of subpart G of this chapter are not met since there has... maintenance of the national ambient air quality standards for sulfur oxides on the island of St. Croix. (b...

40 CFR 52.2780 - Control strategy for sulfur oxides.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 5 2014-07-01 2014-07-01 false Control strategy for sulfur oxides. 52... strategy for sulfur oxides. (a) The requirements of subpart G of this chapter are not met since there has... maintenance of the national ambient air quality standards for sulfur oxides on the island of St. Croix. (b...

40 CFR 52.2780 - Control strategy for sulfur oxides.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 5 2013-07-01 2013-07-01 false Control strategy for sulfur oxides. 52... strategy for sulfur oxides. (a) The requirements of subpart G of this chapter are not met since there has... maintenance of the national ambient air quality standards for sulfur oxides on the island of St. Croix. (b...

40 CFR 52.2780 - Control strategy for sulfur oxides.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 5 2012-07-01 2012-07-01 false Control strategy for sulfur oxides. 52... strategy for sulfur oxides. (a) The requirements of subpart G of this chapter are not met since there has... maintenance of the national ambient air quality standards for sulfur oxides on the island of St. Croix. (b...

Green and scalable production of colloidal perovskite nanocrystals and transparent sols by a controlled self-collection process

NASA Astrophysics Data System (ADS)

Liu, Shuangyi; Huang, Limin; Li, Wanlu; Liu, Xiaohua; Jing, Shui; Li, Jackie; O'Brien, Stephen

2015-07-01

Colloidal perovskite oxide nanocrystals have attracted a great deal of interest owing to the ability to tune physical properties by virtue of the nanoscale, and generate thin film structures under mild chemical conditions, relying on self-assembly or heterogeneous mixing. This is particularly true for ferroelectric/dielectric perovskite oxide materials, for which device applications cover piezoelectrics, MEMs, memory, gate dielectrics and energy storage. The synthesis of complex oxide nanocrystals, however, continues to present issues pertaining to quality, yield, % crystallinity, purity and may also suffer from tedious separation and purification processes, which are disadvantageous to scaling production. We report a simple, green and scalable ``self-collection'' growth method that produces uniform and aggregate-free colloidal perovskite oxide nanocrystals including BaTiO3 (BT), BaxSr1-xTiO3 (BST) and quaternary oxide BaSrTiHfO3 (BSTH) in high crystallinity and high purity. The synthesis approach is solution processed, based on the sol-gel transformation of metal alkoxides in alcohol solvents with controlled or stoichiometric amounts of water and in the stark absence of surfactants and stabilizers, providing pure colloidal nanocrystals in a remarkably low temperature range (15 °C-55 °C). Under a static condition, the nanoscale hydrolysis of the metal alkoxides accomplishes a complete transformation to fully crystallized single domain perovskite nanocrystals with a passivated surface layer of hydroxyl/alkyl groups, such that the as-synthesized nanocrystals can exist in the form of super-stable and transparent sol, or self-accumulate to form a highly crystalline solid gel monolith of nearly 100% yield for easy separation/purification. The process produces high purity ligand-free nanocrystals excellent dispersibility in polar solvents, with no impurity remaining in the mother solution other than trace alcohol byproducts (such as isopropanol). The afforded stable and transparent suspension/solution can be treated as inks, suitable for printing or spin/spray coating, demonstrating great capabilities of this process for fabrication of high performance dielectric thin films. The simple ``self-collection'' strategy can be described as green and scalable due to the simplified procedure from synthesis to separation/purification, minimum waste generation, and near room temperature crystallization of nanocrystal products with tunable sizes in extremely high yield and high purity.Colloidal perovskite oxide nanocrystals have attracted a great deal of interest owing to the ability to tune physical properties by virtue of the nanoscale, and generate thin film structures under mild chemical conditions, relying on self-assembly or heterogeneous mixing. This is particularly true for ferroelectric/dielectric perovskite oxide materials, for which device applications cover piezoelectrics, MEMs, memory, gate dielectrics and energy storage. The synthesis of complex oxide nanocrystals, however, continues to present issues pertaining to quality, yield, % crystallinity, purity and may also suffer from tedious separation and purification processes, which are disadvantageous to scaling production. We report a simple, green and scalable ``self-collection'' growth method that produces uniform and aggregate-free colloidal perovskite oxide nanocrystals including BaTiO3 (BT), BaxSr1-xTiO3 (BST) and quaternary oxide BaSrTiHfO3 (BSTH) in high crystallinity and high purity. The synthesis approach is solution processed, based on the sol-gel transformation of metal alkoxides in alcohol solvents with controlled or stoichiometric amounts of water and in the stark absence of surfactants and stabilizers, providing pure colloidal nanocrystals in a remarkably low temperature range (15 °C-55 °C). Under a static condition, the nanoscale hydrolysis of the metal alkoxides accomplishes a complete transformation to fully crystallized single domain perovskite nanocrystals with a passivated surface layer of hydroxyl/alkyl groups, such that the as-synthesized nanocrystals can exist in the form of super-stable and transparent sol, or self-accumulate to form a highly crystalline solid gel monolith of nearly 100% yield for easy separation/purification. The process produces high purity ligand-free nanocrystals excellent dispersibility in polar solvents, with no impurity remaining in the mother solution other than trace alcohol byproducts (such as isopropanol). The afforded stable and transparent suspension/solution can be treated as inks, suitable for printing or spin/spray coating, demonstrating great capabilities of this process for fabrication of high performance dielectric thin films. The simple ``self-collection'' strategy can be described as green and scalable due to the simplified procedure from synthesis to separation/purification, minimum waste generation, and near room temperature crystallization of nanocrystal products with tunable sizes in extremely high yield and high purity. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr02351c

Y1Ba2Cu3O(7-delta) thin film dc SQUIDs (superconducting quantum interference device)

NASA Astrophysics Data System (ADS)

Racah, Daniel

1991-03-01

Direct current superconducting quantum interferometers (SQUIDs) based on HTSC thin films have been measured and characterized. The thin films used were of different quality: (1) Granular films on Sapphire substrates, prepared either by e-gun evaporation, by laser ablation or by MOCVD (metal oxide chemical vapor deposition), (2) Epitaxial films on MgO substrates. Modulations of the voltage on the SQUIDs as a function of the applied flux have been observed in a wide range of temperatures. The nature of the modulation was found to be strongly dependent on the morphology of the film and on its critical current. The SQUIDs based on granular films were relatively noisy, hysteretic and with a complicated V-phi shape. Those devices based on low quality (lowIc) granular films could be measured only at low temperatures (much lower than 77 K). While those of higher quality (granular films with high Ic) could be measured near to the superconductive transition. The SQUID based on high quality epitaxial film was measured near Tc and showed an anomalous, time dependent behavior.

Controlling the defects and transition layer in SiO2 films grown on 4H-SiC via direct plasma-assisted oxidation

PubMed Central

Kim, Dae-Kyoung; Jeong, Kwang-Sik; Kang, Yu-Seon; Kang, Hang-Kyu; Cho, Sang W.; Kim, Sang-Ok; Suh, Dongchan; Kim, Sunjung; Cho, Mann-Ho

2016-01-01

The structural stability and electrical performance of SiO2 grown on SiC via direct plasma-assisted oxidation were investigated. To investigate the changes in the electronic structure and electrical characteristics caused by the interfacial reaction between the SiO2 film (thickness ~5 nm) and SiC, X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy (XAS), density functional theory (DFT) calculations, and electrical measurements were performed. The SiO2 films grown via direct plasma-assisted oxidation at room temperature for 300s exhibited significantly decreased concentrations of silicon oxycarbides (SiOxCy) in the transition layer compared to that of conventionally grown (i.e., thermally grown) SiO2 films. Moreover, the plasma-assisted SiO2 films exhibited enhanced electrical characteristics, such as reduced frequency dispersion, hysteresis, and interface trap density (Dit ≈ 1011 cm−2 · eV−1). In particular, stress induced leakage current (SILC) characteristics showed that the generation of defect states can be dramatically suppressed in metal oxide semiconductor (MOS) structures with plasma-assisted oxide layer due to the formation of stable Si-O bonds and the reduced concentrations of SiOxCy species defect states in the transition layer. That is, energetically stable interfacial states of high quality SiO2 on SiC can be obtained by the controlling the formation of SiOxCy through the highly reactive direct plasma-assisted oxidation process. PMID:27721493

Changes imposed by pyrolysis, thermal gasification and incineration on composition and phosphorus fertilizer quality of municipal sewage sludge.

PubMed

Thomsen, Tobias Pape; Sárossy, Zsuzsa; Ahrenfeldt, Jesper; Henriksen, Ulrik B; Frandsen, Flemming J; Müller-Stöver, Dorette Sophie

2017-08-01

Fertilizer quality of ash and char from incineration, gasification and pyrolysis of a single municipal sewage sludge sample were investigated by comparing composition and phosphorus (P) plant availability. A process for post oxidation of gasification ash and pyrolysis char was developed and the oxidized materials were investigated as well. Sequential extraction with full elemental balances of the extracted pools as well as scanning electron microscopy with energy dispersive X-ray spectroscopy were used to investigate the mechanisms driving the observed differences in composition and P plant availability in a short-term soil incubation study. The compositional changes related mainly to differences in the proximate composition as well as to the release of especially nitrogen, sulfur, cadmium and to some extent, phosphorus (P). The cadmium load per unit of P was reduced with 75-85% in gasification processes and 10-15% in pyrolysis whereas no reduction was observed in incineration processes. The influence on other heavy metals was less pronounced. The plant availability of P in the substrates varied from almost zero to almost 100% of the plant availability of P in the untreated sludge. Post-oxidized slow pyrolysis char was found to be the substrate with the highest P fertilizer value while ash from commercial fluid bed sludge incineration had the lowest P fertilizer quality. The high P fertilizer value in the best substrate is suggested to be a function of several different mechanisms including structural surface changes and improvements in the association of P to especially magnesium, calcium and aluminum. Copyright © 2017 Elsevier Ltd. All rights reserved.

Kudzu (Pueraria montana) invasion doubles emissions of nitric oxide and increases ozone pollution.

PubMed

Hickman, Jonathan E; Wu, Shiliang; Mickley, Loretta J; Lerdau, Manuel T

2010-06-01

The nitrogen-fixing legume kudzu (Pueraria montana) is a widespread invasive plant in the southeastern United States with physiological traits that may lead to important impacts on ecosystems and the atmosphere. Its spread has the potential to raise ozone levels in the region by increasing nitric oxide (NO) emissions from soils as a consequence of increasing nitrogen (N) inputs and cycling in soils. We studied the effects of kudzu invasions on soils and trace N gas emissions at three sites in Madison County, Georgia in 2007 and used the results to model the effects of kudzu invasion on regional air quality. We found that rates of net N mineralization increased by up to 1,000%, and net nitrification increased by up to 500% in invaded soils in Georgia. Nitric oxide emissions from invaded soils were more than 100% higher (2.81 vs. 1.24 ng NO-N cm(-2) h(-1)). We used the GEOS-Chem chemical transport model to evaluate the potential impact of kudzu invasion on regional atmospheric chemistry and air quality. In an extreme scenario, extensive kudzu invasion leads directly to an increase in the number of high ozone events (above 70 ppb) of up to 7 days each summer in some areas, up from 10 to 20 days in a control scenario with no kudzu invasion. These results establish a quantitative link between a biological invasion and ozone formation and suggest that in this extreme scenario, kudzu invasion can overcome some of the air quality benefits of legislative control.

Influence of spike lavender (Lavandula latifolia Med.) essential oil in the quality, stability and composition of soybean oil during microwave heating.

PubMed

Rodrigues, Nuno; Malheiro, Ricardo; Casal, Susana; Asensio-S-Manzanera, M Carmen; Bento, Albino; Pereira, José Alberto

2012-08-01

Lipids oxidation is one of the main factors leading to quality losses in foods. Its prevention or delay could be obtained by the addition of antioxidants. In this sense the present work intend to monitor the protective effects of Lavandula latifolia essential oil during soybean oil microwave heating. To achieve the proposed goal quality parameters (free acidity, peroxide value, specific coefficients of extinction and ΔK), fatty acids profile, tocopherols and tocotrienols composition, antioxidant activity and oxidative stability were evaluated in soybean oil with and without spike lavender essential oils (EO) submitted to different microwave heating exposure times (1, 3, 5, 10 and 15 min; 1000 Watt) with a standard domestic microwave equipment. Microwave heating induced severe quality and composition losses, mainly above 3 min of microwave heating, regardless the sample tested. However, spike lavender EO addition counteracts the oxidation comparatively to control oils, by presenting enhanced values in quality parameters. A higher protection in unsaturated fatty acids loss was also observed as well as a higher antioxidant activity and oxidative stability. The microwave heating effects were clearly different in the samples with essential oils addition, allowing discrimination from plain soybean oils by a principal component analysis, being also capable to discriminate the different heating times tested within each sample. Copyright © 2012 Elsevier Ltd. All rights reserved.

Economically attractive route for the preparation of high quality magnetic nanoparticles by the thermal decomposition of iron(III) acetylacetonate.

PubMed

Effenberger, Fernando B; Couto, Ricardo A; Kiyohara, Pedro K; Machado, Giovanna; Masunaga, Sueli H; Jardim, Renato F; Rossi, Liane M

2017-03-17

The thermal decomposition (TD) methods are among the most successful in obtaining magnetic nanoparticles with a high degree of control of size and narrow particle size distribution. Here we investigated the TD of iron(III) acetylacetonate in the presence of oleic acid, oleylamine, and a series of alcohols in order to disclose their role and also investigate economically attractive alternatives for the synthesis of iron oxide nanoparticles without compromising their size and shape control. We have found that some affordable and reasonably less priced alcohols, such as 1,2-octanediol and cyclohexanol, may replace the commonly used and expensive 1,2-hexadecanediol, providing an economically attractive route for the synthesis of high quality magnetic nanoparticles. The relative cost for the preparation of Fe 3 O 4 NPs is reduced to only 21% and 9% of the original cost when using 1,2-octanediol and cyclohexanol, respectively.

Controlled assembly of graphene-capped nickel, cobalt and iron silicides

PubMed Central

Vilkov, O.; Fedorov, A.; Usachov, D.; Yashina, L. V.; Generalov, A. V.; Borygina, K.; Verbitskiy, N. I.; Grüneis, A.; Vyalikh, D. V.

2013-01-01

The unique properties of graphene have raised high expectations regarding its application in carbon-based nanoscale devices that could complement or replace traditional silicon technology. This gave rise to the vast amount of researches on how to fabricate high-quality graphene and graphene nanocomposites that is currently going on. Here we show that graphene can be successfully integrated with the established metal-silicide technology. Starting from thin monocrystalline films of nickel, cobalt and iron, we were able to form metal silicides of high quality with a variety of stoichiometries under a Chemical Vapor Deposition grown graphene layer. These graphene-capped silicides are reliably protected against oxidation and can cover a wide range of electronic materials/device applications. Most importantly, the coupling between the graphene layer and the silicides is rather weak and the properties of quasi-freestanding graphene are widely preserved. PMID:23835625

Ultrasonic Spray Drying vs High Vacuum and Microwaves Technology for Blueberries

NASA Astrophysics Data System (ADS)

Candia-Muñoz, N.; Ramirez-Bunster, M.; Vargas-Hernández, Y.; Gaete-Garretón, L.

Interest in high quality foods: good taste and a high content of nutrients with healthy beneficial effects are increasing. Fruits have good properties but, they are lost because the oxidation process, additionally, for different reasons a 40% of harvested fruit are lost. To conserve the fruit properties an ultrasonic assisted spray dryer was developed and tested, comparing its results with microwave-vacuum drying technology. Results did shown taste, color, smell, particle shape and size distribution better than the conventional one. The antioxidants conservation were quite good except in the anthocyanins, in which the microwave and vacuum technology shown best results.

The synthesis and application of fine particles for coatings and composites

NASA Astrophysics Data System (ADS)

Stephenson, Richard Charles

A variety of coating methods are presented for producing titanium and zirconium oxide coatings on spherical alpha-alumina substrates. Some methods did not completely coat the alumina substrate leaving surface areas exposed. Techniques such as surface modifications with PDVB and 4-VP did produce coatings of metal oxides of very high quality. The best metal oxide coatings are produced from pre-treatment of the alumina microspheres followed by the acid catalyzed hydrolysis of the metal tetra-alkoxides. Methods to investigate converting titanium oxide and zirconium oxide coated alumina microspheres to the corresponding metal carbide coated alumina microspheres have been done. The methods involving direct reduction of the metal oxides by methane and methane-hydrogen gas proved inefficient in producing high quality metal carbide coatings. It is evident higher processing temperatures are required to achieve good metal carbide yield by these methods. Metal oxide coated products carbided by ART (Buffalo, NY) proved the carbiding can be accomplished at higher temperatures and with a different carburizing gas. In addition to the ART carbiding method, the magnesium thermite reaction is a promising method in converting metal oxides to metal carbides at much lower temperatures and shorter processing times. The electrophoretic deposition of Bi2Sr2CaCu 2O8 powder was in ethanol. Of critical consequence were the design of the cathode geometry and the arrangement of the electrodes so that all faces and edges of the silver anode were coated simultaneously. This was achieved by shaping the platinum cathode into a configuration that allowed the silver tape to be completely surrounded by the platinum. The electrophoretic cell was set up to keep the electrodes stationary thereby maintaining a constant distance from the cathode and anode (3 mm). The relationship between deposition time and coating thickness was determined for various powder loadings for a given electric field strength (62 V). For low powder loadings (10 and 20 g/L), the thickness of the coating increases with increasing deposition time (6, 12, and 24 hours). At a powder loading of 30 g/L, the thickness of the BSCCO layer decreases from a deposition time of 6 to 12 hours. At 24 hours, the layer thickness increases. Very high powder loadings (40 g/L) showed a linear decrease in the BSCCO layer thickness with increasing deposition time. Analysis by XRD showed the EPD superconductor exhibited preferential orientation on the silver tape. The degree of orientation was related to the layer thickness and hence the deposition times. Thermal treatment at 800°C in 90% Ar-10% O2 improved the orientation effects. A marked improvement in the surface texture was also observed by SEM. Carbon nanotubes were synthesized via Fe catalysis in an aerosol column in the presence of Ar, CO, and H2 gas. Fe particles were generated by the thermal decarbonylation of Fe(CO)5. Multiwalled and single-walled carbon nanotubes were grown from the decomposition of CO gas on the forming Fe particles. Optimal conditions were determined for producing high yields of single-walled nanotubes. A growth theory is proposed based on the results. (Abstract shortened by UMI.)

Development of Self-Healing Zirconium-Silicide Coatings for Improved Performance Zirconium-Alloy Fuel Cladding

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sridharan, Kumar; Mariani, Robert; Bai, Xianming

Zirconium-alloy fuel claddings have been used successfully in Light Water Reactors (LWR) for over four decades. However, under high temperature accident conditions, zirconium-alloys fuel claddings exhibit profuse exothermic oxidation accompanied by release of hydrogen gas due to the reaction with water/steam. Additionally, the ZrO 2 layer can undergo monoclinic to tetragonal to cubic phase transformations at high temperatures which can induce stresses and cracking. These events were unfortunately borne out in the Fukushima-Daiichi accident in in Japan in 2011. In reaction to such accident, protective oxidation-resistant coatings for zirconium-alloy fuel claddings has been extensively investigated to enhance safety margins inmore » accidents as well as fuel performance under normal operation conditions. Such surface modification could also beneficially affect fuel rod heat transfer characteristics. Zirconium-silicide, a candidate coating material, is particularly attractive because zirconium-silicide coating is expected to bond strongly to zirconium-alloy substrate. Intermetallic compound phases of zirconium-silicide have high melting points and oxidation of zirconium silicide produces highly corrosion resistant glassy zircon (ZrSiO 4) and silica (SiO 2) which possessing self-healing qualities. Given the long-term goal of developing such coatings for use with nuclear reactor fuel cladding, this work describes results of oxidation and corrosion behavior of bulk zirconium-silicide and fabrication of zirconium-silicide coatings on zirconium-alloy test flats, tube configurations, and SiC test flats. In addition, boiling heat transfer of these modified surfaces (including ZrSi 2 coating) during clad quenching experiments is discussed in detail.« less

Note: Application of CR-39 plastic nuclear track detectors for quality assurance of mixed oxide fuel pellets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kodaira, S., E-mail: koda@nirs.go.jp; Kurano, M.; Hosogane, T.

A CR-39 plastic nuclear track detector was used for quality assurance of mixed oxide fuel pellets for next-generation nuclear power plants. Plutonium (Pu) spot sizes and concentrations in the pellets are significant parameters for safe use in the plants. We developed an automatic Pu detection system based on dense α-radiation tracks in the CR-39 detectors. This system would greatly improve image processing time and measurement accuracy, and will be a powerful tool for rapid pellet quality assurance screening.

Development of marker-free transgenic Jatropha plants with increased levels of seed oleic acid

PubMed Central

2012-01-01

Background Jatropha curcas is recognized as a new energy crop due to the presence of the high amount of oil in its seeds that can be converted into biodiesel. The quality and performance of the biodiesel depends on the chemical composition of the fatty acids present in the oil. The fatty acids profile of the oil has a direct impact on ignition quality, heat of combustion and oxidative stability. An ideal biodiesel composition should have more monounsaturated fatty acids and less polyunsaturated acids. Jatropha seed oil contains 30% to 50% polyunsaturated fatty acids (mainly linoleic acid) which negatively impacts the oxidative stability and causes high rate of nitrogen oxides emission. Results The enzyme 1-acyl-2-oleoyl-sn-glycero-3-phosphocholine delta 12-desaturase (FAD2) is the key enzyme responsible for the production of linoleic acid in plants. We identified three putative delta 12 fatty acid desaturase genes in Jatropha (JcFAD2s) through genome-wide analysis and downregulated the expression of one of these genes, JcFAD2-1, in a seed-specific manner by RNA interference technology. The resulting JcFAD2-1 RNA interference transgenic plants showed a dramatic increase of oleic acid (> 78%) and a corresponding reduction in polyunsaturated fatty acids (< 3%) in its seed oil. The control Jatropha had around 37% oleic acid and 41% polyunsaturated fatty acids. This indicates that FAD2-1 is the major enzyme responsible for converting oleic acid to linoleic acid in Jatropha. Due to the changes in the fatty acids profile, the oil of the JcFAD2-1 RNA interference seed was estimated to yield a cetane number as high as 60.2, which is similar to the required cetane number for conventional premium diesel fuels (60) in Europe. The presence of high seed oleic acid did not have a negative impact on other Jatropha agronomic traits based on our preliminary data of the original plants under greenhouse conditions. Further, we developed a marker-free system to generate the transgenic Jatropha that will help reduce public concerns for environmental issues surrounding genetically modified plants. Conclusion In this study we produced seed-specific JcFAD2-1 RNA interference transgenic Jatropha without a selectable marker. We successfully increased the proportion of oleic acid versus linoleic in Jatropha through genetic engineering, enhancing the quality of its oil. PMID:22377043

Large scale production of highly-qualified graphene by ultrasonic exfoliation of expanded graphite under the promotion of (NH4)2CO3 decomposition.

PubMed

Wang, Yunwei; Tong, Xili; Guo, Xiaoning; Wang, Yingyong; Jin, Guoqiang; Guo, Xiangyun

2013-11-29

Highly-qualified graphene was prepared by the ultrasonic exfoliation of commercial expanded graphite (EG) under the promotion of (NH4)2CO3 decomposition. The yield of graphene from the first exfoliation is 7 wt%, and it can be increased to more than 65 wt% by repeated exfoliations. Atomic force microscopy, x-ray photoelectron spectroscopy and Raman analysis show that the as-prepared graphene only has a few defects or oxides, and more than 95% of the graphene flakes have a thickness of ~1 nm. The electrochemical performance of the as-prepared graphene is comparable to reduced graphene oxide in the determination of dopamine (DA) from the mixed solution of ascorbic acid, uric acid and DA. These results show that the decomposition of (NH4)2CO3 molecules in the EG layers under ultrasonication promotes the exfoliation of graphite and provides a low-priced route for large scale production of highly-quality graphene.

Large scale production of highly-qualified graphene by ultrasonic exfoliation of expanded graphite under the promotion of (NH4)2CO3 decomposition

NASA Astrophysics Data System (ADS)

Wang, Yunwei; Tong, Xili; Guo, Xiaoning; Wang, Yingyong; Jin, Guoqiang; Guo, Xiangyun

2013-11-01

Highly-qualified graphene was prepared by the ultrasonic exfoliation of commercial expanded graphite (EG) under the promotion of (NH4)2CO3 decomposition. The yield of graphene from the first exfoliation is 7 wt%, and it can be increased to more than 65 wt% by repeated exfoliations. Atomic force microscopy, x-ray photoelectron spectroscopy and Raman analysis show that the as-prepared graphene only has a few defects or oxides, and more than 95% of the graphene flakes have a thickness of ˜1 nm. The electrochemical performance of the as-prepared graphene is comparable to reduced graphene oxide in the determination of dopamine (DA) from the mixed solution of ascorbic acid, uric acid and DA. These results show that the decomposition of (NH4)2CO3 molecules in the EG layers under ultrasonication promotes the exfoliation of graphite and provides a low-priced route for large scale production of highly-quality graphene.

Transparent and conductive indium doped cadmium oxide thin films prepared by pulsed filtered cathodic arc deposition

DOE PAGES

Zhu, Yuankun; Mendelsberg, Rueben J.; Zhu, Jiaqi; ...

2012-11-26

Indium doped cadmium oxide (CdO:In) films with different In concentrations were prepared on low-cost glass substrates by pulsed filtered cathodic arc deposition (PFCAD). In this study, it is shown that polycrystalline CdO:In films with smooth surface and dense structure are obtained. In-doping introduces extra electrons leading to remarkable improvements of electron mobility and conductivity, as well as improvement in the optical transmittance due to the Burstein Moss effect. CdO:In films on glass substrates with thickness near 230 nm show low resistivity of 7.23 x 10 -5 Ωcm, high electron mobility of 142 cm 2/Vs, and mean transmittance over 80% frommore » 500-1250 nm (including the glass substrate). These high quality pulsed arc-grown CdO:In films are potentially suitable for high efficiency multi-junction solar cells that harvest a broad range of the solar spectrum.« less

Soft Nanoimprint Lithography for Direct Printing of Crystalline Metal Oxide Nanostructures

NASA Astrophysics Data System (ADS)

Kothari, Rohit; Beaulieu, Michael; Watkins, James

2015-03-01

We demonstrate a solution-based soft nanoimprint lithography technique to directly print dimensionally-stable crystalline metal oxide nanostructures. A patterned PDMS stamp is used in combination with a UV/thermal cure step to imprint a resist containing high concentrations of crystalline nanoparticles in an inorganic/organic binder phase. The as-imprinted nanostructures are highly crystalline and therefore undergo little shrinkage (less than 5% in some cases) upon thermal annealing. High aspect ratio nanostructures and sub-100 nm features are easily realized. Residual layer free direct imprinting (no etching) was achieved by choosing the resist with the appropriate surface energy to ensure dewetting at stamp-substrate interface. The technique was further extended to stack the nanostructures by deploying a layer-by-layer imprint strategy. The method is scalable and can produce large area device quality nanostructures in a rapid fashion at a low cost. CeO2, ITO and TiO2 nanopatterns are illustrated for their potential use in fuel cell electrodes, solar cell electrodes and photonic devices, respectively.