WorldWideScience

Sample records for accelerated-senescence oxys rats

  1. Improving Bone Microarchitecture in Aging with Diosgenin Treatment: A Study in Senescence-Accelerated OXYS Rats.

    Tikhonova, Maria A; Ting, Che-Hao; Kolosova, Nataliya G; Hsu, Chao-Yu; Chen, Jian-Horng; Huang, Chi-Wen; Tseng, Ging-Ting; Hung, Ching-Sui; Kao, Pan-Fu; Amstislavskaya, Tamara G; Ho, Ying-Jui

    2015-10-31

    Osteoporosis is a major disease associated with aging. We have previously demonstrated that diosgenin prevents osteoporosis in both menopause and D-galactose-induced aging rats. OXYS rats reveal an accelerated senescence and are used as a suitable model of osteoporosis. The aim of the present study was to analyze microarchitecture and morphological changes in femur of OXYS rats using morphological tests and microcomputed tomography scanning, and to evaluate the effects of oral administration of diosgenin at 10 and 50 mg/kg/day on femur in OXYS rats. The result showed that, compared with age-matched Wistar rats, the femur of OXYS rats revealed lower bone length, bone weight, bone volume, frame volume, frame density, void volume, porosity, external and internal diameters, cortical bone area, BV/TV, Tb.N, and Tb.Th, but higher Tb.Sp. Eight weeks of diosgenin treatment decreased porosity and Tb.Sp, but increased BV/TV, cortical bone area, Tb.N and bone mineral density, compared with OXYS rats treated with vehicle. These data reveal that microarchitecture and morphological changes in femur of OXYS rats showed osteoporotic aging features and suggest that diosgenin may have beneficial effects on aging-induced osteoporosis. PMID:26387656

  2. 19F NMR measurements of NO production in hypertensive ISIAH and OXYS rats

    Recently we demonstrated the principal possibility of application of 19F NMR spin-trapping technique for in vivo ·NO detection [Free Radic. Biol. Med. 36 (2004) 248]. In the present study, we employed this method to elucidate the significance of ·NO availability in animal models of hypertension. In vivo ·NO-induced conversion of the hydroxylamine of the fluorinated nitronyl nitroxide (HNN) to the hydroxylamine of the iminonitroxide (HIN) in hypertensive ISIAH and OXYS rat strains and normotensive Wistar rat strain was measured. Significantly lower HIN/HNN ratios were measured in the blood of the hypertensive rats. The NMR data were found to positively correlate with the levels of nitrite/nitrate evaluated by Griess method and negatively correlate with the blood pressure. In comparison with other traditionally used methods 19F NMR spectroscopy allows in vivo evaluation of ·NO production and provides the basis for in vivo ·NO imaging

  3. The Mitochondria-Targeted Antioxidant SkQ1 Downregulates Aryl Hydrocarbon Receptor-Dependent Genes in the Retina of OXYS Rats with AMD-Like Retinopathy

    M. L. Perepechaeva

    2014-01-01

    Full Text Available The mitochondria-targeted antioxidant SkQ1 is a novel drug thought to retard development of age-related diseases. It has been shown that SkQ1 reduces clinical signs of retinopathy in senescence-accelerated OXYS rats, which are a known animal model of human age-related macular degeneration (AMD. The aim of this work was to test whether SkQ1 affects transcriptional activity of AhR (aryl hydrocarbon receptor and Nrf2 (nuclear factor erythroid 2-related factor 2, which are considered as AMD-associated genes in the retina of OXYS and Wistar rats. Our results showed that only AhR and AhR-dependent genes were sensitive to SkQ1. Dietary supplementation with SkQ1 decreased the AhR mRNA level in both OXYS and Wistar rats. At baseline, the retinal Cyp1a1 mRNA level was lower in OXYS rats. SkQ1 supplementation decreased the Cyp1a1 mRNA level in Wistar rats, but this level remained unchanged in OXYS rats. Baseline Cyp1a2 and Cyp1b1 mRNA expression was stronger in OXYS than in Wistar rats. In the OXYS strain, Cyp1a2 and Cyp1b1 mRNA levels decreased as a result of SkQ1 supplementation. These data suggest that the Cyp1a2 and Cyp1b1 enzymes are involved in the pathogenesis of AMD-like retinopathy of OXYS rats and are possible therapeutic targets of SkQ1.

  4. A higher oxidative status accelerates senescence and aggravates age-dependent disorders in SAMP strains of mice.

    Hosokawa, Masanori

    2002-11-01

    The SAM strain of mice is actually a group of related inbred strains consisting of series of SAMP (accelerated senescence-prone, short-lived) and SAMR (accelerated senescence-resistant, longer-lived) strains. Comparing with the SAMR strains, the SAMP strains of mice show a more accelerated senescence process, shorter lifespan, and an earlier onset and more rapid progress of age-associated pathological phenotypes similar to several geriatric disorders observed in humans, including senile osteoporosis, degenerative joint disease, age-related deficits in learning and memory, olfactory bulb and forebrain atrophy, presbycusis and retinal atrophy, senile amyloidosis, immunosenescence, senile lungs, and diffuse medial thickening of the aorta. The higher oxidative stress observed in the SAMP strains of mice are partly caused by mitochondrial dysfunction, and may be one cause of the senescence acceleration and age-dependent alterations in cell structure and function, including neuronal cell degeneration. This senescence acceleration is also observed during senescence/crisis in cultures of isolated fibroblast-like cells from SAMP strains of mice, and was associated with a hyperoxidative status. These observations suggest that the SAM strains are useful tools in the attempt to understand the mechanisms of age-dependent degeneration of cells and tissues, and their aggravation, and to develop clinical interventions. PMID:12470893

  5. Effects of the Oxygen-Carrying Solution OxyVita C on the Cerebral Microcirculation and Systemic Blood Pressures in Healthy Rats

    Rania Abutarboush

    2014-11-01

    Full Text Available The use of hemoglobin-based oxygen carriers (HBOC as oxygen delivering therapies during hypoxic states has been hindered by vasoconstrictive side effects caused by depletion of nitric oxide (NO. OxyVita C is a promising oxygen-carrying solution that consists of a zero-linked hemoglobin polymer with a high molecular weight (~17 MDa. The large molecular weight is believed to prevent extravasation and limit NO scavenging and vasoconstriction. The aim of this study was to assess vasoactive effects of OxyVita C on systemic blood pressures and cerebral pial arteriole diameters. Anesthetized healthy rats received four intravenous (IV infusions of an increasing dose of OxyVita C (2, 25, 50, 100 mg/kg and hemodynamic parameters and pial arteriolar diameters were measured pre- and post-infusion. Normal saline was used as a volume-matched control. Systemic blood pressures increased (P ≤ 0.05 with increasing doses of OxyVita C, but not with saline. There was no vasoconstriction in small (<50 µm and medium-sized (50–100 µm pial arterioles in the OxyVita C group. In contrast, small and medium-sized pial arterioles vasoconstricted in the control group. Compared to saline, OxyVita C showed no cerebral vasoconstriction after any of the four doses evaluated in this rat model despite increases in blood pressure.

  6. Therapeutic action of the mitochondria-targeted antioxidant SkQ1 on retinopathy in OXYS rats linked with improvement of VEGF and PEDF gene expression.

    Anton M Markovets

    Full Text Available UNLABELLED: The incidence of age-related macular degeneration (AMD, the main cause of blindness in older patients in the developed countries, is increasing with the ageing population. At present there is no effective treatment for the prevailing geographic atrophy, dry AMD, whereas antiangiogenic therapies successful used in managing the wet form of AMD. Recently we showed that mitochondria-targeted antioxidant plastoquinonyl-decyl-triphenylphosphonium (SkQ1 is able to prevent the development and moreover caused regression of pre-existing signs of the retinopathy in OXYS rats, an animal model of AMD. Here we examine the effects of SkQ1 on expression of key regulators of angiogenesis vascular endothelial growth factor A (VEGF and its antagonist pigment epithelium-derived factor (PEDF genes in the retina of OXYS rats as evidenced by real-time PCR and an ELISA test for VEGF using Wistar rats as control. Ophthalmoscopic examinations confirmed that SkQ1 supplementation (from 1.5 to 3 months of age, 250 nmol/kg prevented development while eye drops SkQ1 (250 nM, from 9 to 12 months caused some reduction of retinopathy signs in OXYS rats and did not reveal any negative effects on the control Wistar rat's retina. Prevention of premature retinopathy by SkQ1 was connected with an increase of VEGF mRNA and protein in OXYS rat's retina up to the levels corresponding to the Wistar rats, and did not involve changes in PEDF expression. In contrast the treatment with SkQ1 drops caused a decrease of VEGF mRNA and protein levels and an increase in the PEDF mRNA level in the middle-aged OXYS rats, but in Wistar rats the changes of gene expression were the opposite. CONCLUSIONS: The beneficial effects of SkQ1 on retinopathy connected with normalization of expression of VEGF and PEDF in the retina of OXYS rats and depended on age of the animals and the stage of retinopathy.

  7. Co-targeting Deoxyribonucleic Acid–Dependent Protein Kinase and Poly(Adenosine Diphosphate-Ribose) Polymerase-1 Promotes Accelerated Senescence of Irradiated Cancer Cells

    Azad, Arun, E-mail: arun.azad@bccancer.bc.ca [Division of Cancer Research, Peter MacCallum Cancer Centre, East Melbourne, Victoria (Australia); Department of Pathology, St. Vincent' s Hospital, University of Melbourne, Parkville, Victoria (Australia); Bukczynska, Patricia; Jackson, Susan [Division of Cancer Research, Peter MacCallum Cancer Centre, East Melbourne, Victoria (Australia); Haput, Ygal; Cullinane, Carleen [Division of Cancer Research, Peter MacCallum Cancer Centre, East Melbourne, Victoria (Australia); Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Victoria (Australia); McArthur, Grant A.; Solomon, Benjamin [Division of Cancer Research, Peter MacCallum Cancer Centre, East Melbourne, Victoria (Australia); Division of Cancer Medicine, Peter MacCallum Cancer Centre, East Melbourne, Victoria (Australia); Department of Medicine, St. Vincent' s Hospital, University of Melbourne, Parkville, Victoria (Australia); Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Victoria (Australia)

    2014-02-01

    Purpose: To examine the effects of combined blockade of DNA-dependent protein kinase (DNA-PK) and poly(adenosine diphosphate-ribose) polymerase-1 (PARP-1) on accelerated senescence in irradiated H460 and A549 non-small cell lung cancer cells. Methods and Materials: The effects of KU5788 and AG014699 (inhibitors of DNA-PK and PARP-1, respectively) on clonogenic survival, DNA double-strand breaks (DSBs), apoptosis, mitotic catastrophe, and accelerated senescence in irradiated cells were examined in vitro. For in vivo experiments, H460 xenografts established in athymic nude mice were treated with BEZ235 (a DNA-PK, ATM, and phosphatidylinositol 3-kinase/mammalian target of rapamycin inhibitor) and AG014699 to determine effects on proliferation, DNA DSBs, and accelerated senescence after radiation. Results: Compared with either inhibitor alone, combination treatment with KU57788 and AG014699 reduced postradiation clonogenic survival and significantly increased persistence of Gamma-H2AX (γH2AX) foci in irradiated H460 and A549 cells. Notably, these effects coincided with the induction of accelerated senescence in irradiated cells as reflected by positive β-galactosidase staining, G2-M cell-cycle arrest, enlarged and flattened cellular morphology, increased p21 expression, and senescence-associated cytokine secretion. In irradiated H460 xenografts, concurrent therapy with BEZ235 and AG014699 resulted in sustained Gamma-H2AX (γH2AX) staining and prominent β-galactosidase activity. Conclusion: Combined DNA-PK and PARP-1 blockade increased tumor cell radiosensitivity and enhanced the prosenescent properties of ionizing radiation in vitro and in vivo. These data provide a rationale for further preclinical and clinical testing of this therapeutic combination.

  8. Alpha fucosidase and beta galactosidase in serum of a Lyme disease patients as a possible marker of accelerated senescence — a preliminary study

    Anna Wasiluk

    2012-07-01

    Full Text Available Lyme disease (LD is the most prevalent tick-borne disease in Europe. LD is caused by the spirochete Borrelia burgdorferi. LD is a chronic disease which can attack a number of organs: skin, heart, brain, joints. Chronic, low-grade inflammation involves general production of pro-inflammatory cytokines and inflammatory markers and is a typical feature of aging. So far, the best method of diagnosing LD is a time-consuming and expensive two-stage serological method. The aim of our study was to evaluate the activity of two lysosomal exoglycosidases: α-fucosidase (FUC and β-galactosidase (GAL in the serum of patients with Lyme disease, as potential markers of LD. Due to the increasing number of patients with Lyme disease and a number of false results, new ways to diagnose this disease are still being sought. As elevated level of β-galactosidase is a manifestation of residual lysosomal activity in senescent cells, the increase in its activity in serum during chronic Lyme disease might be a marker of a potentially accelerated senescence process. The study was performed on serum taken from cubital veins of 15 patients with Lyme disease and eight healthy subjects (control group. FUC and GAL activity was measured by the method of Chatterjee et al. as modified by Zwierz et al. In the serum of patients with Lyme disease, GAL activity significantly increased (p = 0.029, and the activity of FUC had a tendency to increase (p = 0.153, compared to the control group. A significant increase in GAL activity in the serum of patients with Lyme disease indicates an increased catabolism of glycoconjugates (glycoproteins, glycolipids, proteoglycans and could be helpful in the diagnosis of Lyme disease, although this requires confirmation in a larger group of patients. As GAL is the most widely used assay for detection of senescent cells, an elevated level of β-galactosidase might be a manifestation of accelerated senescence process in the course of Lyme

  9. OxyContin

    ... OxyContin is taken every 12 hours because the tablets contain a controlled, time-release formulation of the medication. Most pain medications must be taken every three to six hours. OxyContin abusers remove the sustained-release coating to get a rapid release of the medication, ...

  10. The β-carboline alkaloid harmine inhibits telomerase activity of MCF-7 cells by down-regulating hTERT mRNA expression accompanied by an accelerated senescent phenotype

    Lei Zhao

    2013-10-01

    Full Text Available The end replication problem, which occurs in normal somatic cells inducing replicative senescence, is solved in most cancer cells by activating telomerase. The activity of telomerase is highly associated with carcinogenesis which makes the enzyme an attractive biomarker in cancer diagnosis and treatment. The indole alkaloid harmine has multiple pharmacological properties including DNA intercalation which can lead to frame shift mutations. In this study, harmine was applied to human breast cancer MCF-7 cells. Its activity towards telomerase was analyzed by utilizing the telomeric repeat amplification protocol (TRAP. Our data indicate that harmine exhibits a pronounced cytotoxicity and induces an anti-proliferation state in MCF-7 cells which is accompanied by a significant inhibition of telomerase activity and an induction of an accelerated senescence phenotype by over-expressing elements of the p53/p21 pathway.

  11. Effects of the cFMS kinase inhibitor 5-(3-methoxy-4-((4-methoxybenzyl)oxy)benzyl)pyrimidine-2,4-diamine (GW2580) in normal and arthritic rats.

    Conway, James G; Pink, Heather; Bergquist, Mandy L; Han, Bajin; Depee, Scott; Tadepalli, Sarva; Lin, Peiyuan; Crumrine, R Christian; Binz, Jane; Clark, Richard L; Selph, Jeffrey L; Stimpson, Stephen A; Hutchins, Jeff T; Chamberlain, Stanley D; Brodie, Thomas A

    2008-07-01

    The cFMS (cellular homolog of the V-FMS oncogene product of the Susan McDonough strain of feline sarcoma virus) (Proc Natl Acad Sci U S A 83:3331-3335, 1986) kinase inhibitor 5-(3-methoxy-4-((4-methoxybenzyl)oxy)benzyl)pyrimidine-2,4-diamine (GW2580) inhibits colony-stimulating factor (CSF)-1-induced monocyte growth and bone degradation in vitro and inhibits CSF-1 signaling through cFMS kinase in 4-day models in mice (Proc Natl Acad Sci U S A 102:16078, 2005). In the present study, the kinase selectivity of GW2580 was further characterized, and the effects of chronic treatment were evaluated in normal and arthritic rats. GW2580 selectively inhibited cFMS kinase compared with 186 other kinases in vitro and completely inhibited CSF-1-induced growth of rat monocytes, with an IC(50) value of 0.2 microM. GW2580 dosed orally at 25 and 75 mg/kg 1 and 5 h before the injection of lipopolysaccharide inhibited tumor necrosis factor-alpha production by 60 to 85%, indicating a duration of action of at least 5 h. In a 21-day adjuvant arthritis model, GW2580 dosed twice a day (b.i.d.) from days 0 to 21, 7 to 21, or 14 to 21 inhibited joint connective tissue and bone destruction as assessed by radiology, histology and bone mineral content measurements. In contrast, GW2580 did not affect ankle swelling in the adjuvant model nor did it affect ankle swelling in a model where local arthritis is reactivated by peptidoglycan polysaccharide polymers. GW2580 administered to normal rats for 21 days showed no effects on tissue histology and only modest changes in serum clinical chemistry and blood hematology. In conclusion, GW2580 was effective in preserving joint integrity in the adjuvant arthritis model while showing minimal effects in normal rats. PMID:18434589

  12. Role for the oxyS Gene in Regulation of Intracellular Hydrogen Peroxide in Escherichia coli

    González-Flecha, Beatriz; Demple, Bruce

    1999-01-01

    Intracellular hydrogen peroxide is regulated in Escherichia coli by OxyR in response to the metabolic production of H2O2. Here, we show that the untranslated oxyS RNA controlled by OxyR has a role in this regulation. The oxyS transcript appears to affect the metabolic output of H2O2 rather than the removal of H2O2 by catalases-hydroperoxidases.

  13. Oxy-coal Combustion Studies

    Wendt, J. [Univ. of Utah, Salt Lake City, UT (United States); Eddings, E. [Univ. of Utah, Salt Lake City, UT (United States); Lighty, J. [Univ. of Utah, Salt Lake City, UT (United States); Ring, T. [Univ. of Utah, Salt Lake City, UT (United States); Smith, P. [Univ. of Utah, Salt Lake City, UT (United States); Thornock, J. [Univ. of Utah, Salt Lake City, UT (United States); Y Jia, W. Morris [Univ. of Utah, Salt Lake City, UT (United States); Pedel, J. [Univ. of Utah, Salt Lake City, UT (United States); Rezeai, D. [Univ. of Utah, Salt Lake City, UT (United States); Wang, L. [Univ. of Utah, Salt Lake City, UT (United States); Zhang, J. [Univ. of Utah, Salt Lake City, UT (United States); Kelly, K. [Univ. of Utah, Salt Lake City, UT (United States)

    2012-01-06

    The objective of this project is to move toward the development of a predictive capability with quantified uncertainty bounds for pilot-scale, single-burner, oxy-coal operation. This validation research brings together multi-scale experimental measurements and computer simulations. The combination of simulation development and validation experiments is designed to lead to predictive tools for the performance of existing air fired pulverized coal boilers that have been retrofitted to various oxy-firing configurations. In addition, this report also describes novel research results related to oxy-combustion in circulating fluidized beds. For pulverized coal combustion configurations, particular attention is focused on the effect of oxy-firing on ignition and coal-flame stability, and on the subsequent partitioning mechanisms of the ash aerosol.

  14. The OxyS regulatory RNA represses rpoS translation and binds the Hfq (HF-I) protein.

    Zhang, A.; Altuvia, S; Tiwari, A; Argaman, L; Hengge-Aronis, R; Storz, G.

    1998-01-01

    The OxyS regulatory RNA integrates the adaptive response to hydrogen peroxide with other cellular stress responses and protects against DNA damage. Among the OxyS targets is the rpoS-encoded sigma(s) subunit of RNA polymerase. Sigma(s) is a central regulator of genes induced by osmotic stress, starvation and entry into stationary phase. We examined the mechanism whereby OxyS represses rpoS expression and found that the OxyS RNA inhibits translation of the rpoS message. This repression is depe...

  15. dermaOXY skin assay: effect and evidence

    Menov, Lasse; Klösgen-Buchkremer, Beate Maria

    2015-01-01

    This text is a videnkupon report supported by the Danish Innovation Fonds and conducted by L.M. and B.K. for dermaOXY (by MedicTinedic ApS, Varde, Denmark). It involves two dermaOXY products: dermaOXY HYALURON SERUM and dermaOXY SYN SERUM. These are applied to the facial skin in combination with a...

  16. Oxy-fuel combustion of solid fuels

    Toftegaard, Maja Bøg; Brix, Jacob; Jensen, Peter Arendt;

    2010-01-01

    temperature. The flue gas produced thus consists primarily of carbon dioxide and water. Much research on the different aspects of an oxy-fuel power plant has been performed during the last decade. Focus has mainly been on retrofits of existing pulverized-coal-fired power plant units. Green-field plants which......Oxy-fuel combustion is suggested as one of the possible, promising technologies for capturing CO2 from power plants. The concept of oxy-fuel combustion is removal of nitrogen from the oxidizer to carry out the combustion process in oxygen and, in most concepts, recycled flue gas to lower the flame......-fuel process and focuses particularly on the combustion fundamentals, i.e. flame temperatures and heat transfer, ignition and burnout, emissions, and fly ash characteristics. Knowledge is currently available regarding both an entire oxy-fuel power plant and the combustion fundamentals. However, several...

  17. Oxy-Combustion Boiler Material Development

    Gagliano, Michael; Seltzer, Andrew; Agarwal, Hans; Robertson, Archie; Wang, Lun

    2012-01-31

    Under U.S. Department of Energy Cooperative Agreement No. DE-NT0005262 Foster Wheeler North America Corp conducted a laboratory test program to determine the effect of oxy-combustion on boiler tube corrosion. In this program, CFD modeling was used to predict the gas compositions that will exist throughout and along the walls of air-fired and oxy-fired boilers operating with low to high sulfur coals. Test coupons of boiler tube materials were coated with deposits representative of those coals and exposed to the CFD predicted flue gases for up to 1000 hours. The tests were conducted in electric tube furnaces using oxy-combustion and air-fired flue gases synthesized from pressurized cylinders. Following exposure, the test coupons were evaluated to determine the total metal wastage experienced under air and oxy-combustions conditions and materials recommendations were made. Similar to air-fired operation, oxy-combustion corrosion rates were found to vary with the boiler material, test temperature, deposit composition, and gas composition. Despite this, comparison of air-fired and oxy-fired corrosion rates showed that oxy-firing rates were, for the most part, similar to, if not lower than those of air-firing; this finding applied to the seven furnace waterwall materials (wrought and weld overlay) and the ten superheater/reheater materials (wrought and weld overlay) that were tested. The results of the laboratory oxy-combustion tests, which are based on a maximum bulk flue gas SO2 level of 3200 ppmv (wet) / 4050 ppmv (dry), suggest that, from a corrosion standpoint, the materials used in conventional subcritical and supercritical, air-fired boilers should also be suitable for oxy-combustion retrofits. Although the laboratory test results are encouraging, they are only the first step of a material evaluation process and it is recommended that follow-on corrosion tests be conducted in coal-fired boilers operating under oxy-combustion to provide longer term (one to two year

  18. Oxy-Combustion Boiler Material Development

    Michael Gagliano; Andrew Seltzer; Hans Agarwal; Archie Robertson; Lun Wang

    2012-01-31

    Under U.S. Department of Energy Cooperative Agreement No. DE-NT0005262 Foster Wheeler North America Corp conducted a laboratory test program to determine the effect of oxy-combustion on boiler tube corrosion. In this program, CFD modeling was used to predict the gas compositions that will exist throughout and along the walls of air-fired and oxy-fired boilers operating with low to high sulfur coals. Test coupons of boiler tube materials were coated with deposits representative of those coals and exposed to the CFD predicted flue gases for up to 1000 hours. The tests were conducted in electric tube furnaces using oxy-combustion and air-fired flue gases synthesized from pressurized cylinders. Following exposure, the test coupons were evaluated to determine the total metal wastage experienced under air and oxy-combustions conditions and materials recommendations were made. Similar to air-fired operation, oxy-combustion corrosion rates were found to vary with the boiler material, test temperature, deposit composition, and gas composition. Despite this, comparison of air-fired and oxy-fired corrosion rates showed that oxy-firing rates were, for the most part, similar to, if not lower than those of air-firing; this finding applied to the seven furnace waterwall materials (wrought and weld overlay) and the ten superheater/reheater materials (wrought and weld overlay) that were tested. The results of the laboratory oxy-combustion tests, which are based on a maximum bulk flue gas SO{sub 2} level of 3200 ppmv (wet) / 4050 ppmv (dry), suggest that, from a corrosion standpoint, the materials used in conventional subcritical and supercritical, air-fired boilers should also be suitable for oxy-combustion retrofits. Although the laboratory test results are encouraging, they are only the first step of a material evaluation process and it is recommended that follow-on corrosion tests be conducted in coal-fired boilers operating under oxy-combustion to provide longer term (one to

  19. The Escherichia coli OxyS regulatory RNA represses fhlA translation by blocking ribosome binding.

    Altuvia, S; Zhang, A.; Argaman, L; Tiwari, A; Storz, G.

    1998-01-01

    OxyS is a small untranslated RNA which is induced in response to oxidative stress in Escherichia coli. This novel RNA acts as a global regulator to activate or repress the expression of as many as 40 genes, including the fhlA-encoded transcriptional activator and the rpoS-encoded sigma(s) subunit of RNA polymerase. Deletion analysis of OxyS showed that different domains of the small RNA are required for the regulation of fhlA and rpoS. We examined the mechanism of OxyS repression of fhlA and ...

  20. The mycobacterial LysR-type regulator OxyS responds to oxidative stress and negatively regulates expression of the catalase-peroxidase gene.

    Yuqing Li

    Full Text Available Protection against oxidative stress is one of the primary defense mechanisms contributing to the survival of Mycobacterium tuberculosis in the host. In this study, we provide evidence that OxyS, a LysR-type transcriptional regulator functions as an oxidative stress response regulator in mycobacteria. Overexpression of OxyS lowers expression of the catalase-peroxidase (KatG gene in M. smegmatis. OxyS binds directly with the katG promoter region and a conserved, GC-rich T-N(11-A motif for OxyS binding was successfully characterized in the core binding site. Interestingly, the DNA-binding activity of OxyS was inhibited by H(2O(2, but not by dithiothreitol. Cys25, which is situated at the DNA-binding domain of OxyS, was found to have a regulatory role for the DNA-binding ability of OxyS in response to oxidative stress. In contrast, the other three cysteine residues in OxyS do not appear to have this function. Furthermore, the mycobacterial strain over-expressing OxyS had a higher sensitivity to H(2O(2. Thus, OxyS responds to oxidative stress through a unique cysteine residue situated in its DNA-binding domain and negatively regulates expression of the katG gene. These findings uncover a specific regulatory mechanism for mycobacterial adaptation to oxidative stress.

  1. Modeling of large-scale oxy-fuel combustion processes

    Yin, Chungen

    2012-01-01

    Quite some studies have been conducted in order to implement oxy-fuel combustion with flue gas recycle in conventional utility boilers as an effective effort of carbon capture and storage. However, combustion under oxy-fuel conditions is significantly different from conventional air-fuel firing, among which radiative heat transfer under oxy-fuel conditions is one of the fundamental issues. This paper demonstrates the nongray-gas effects in modeling of large-scale oxy-fuel combustion processes...

  2. Oxy-combustion of high rank coals

    Gómez Borrego, Ángeles; Álvarez Rodríguez, Diego; Fernández Domínguez, Isabel; Ballesteros, Juan Carlos; Menéndez López, Rosa M.ª

    2007-01-01

    One of the ways to face the abatement of CO2 emissions in power plants is the combustion of coal using oxy-fuel technology. In this case coal would be burned in a O2/CO2 atmosphere and the flue gas would consist mainly of CO2 which after condensation of water could be quasy-ready for storage. Most of the work related to oxy-fuel combustion has been applied to high volatile coals. In this study run of mine and single seam coals ranging in rank from low volatile bituminous to meta-anthracite ha...

  3. The Mycobacterial LysR-Type Regulator OxyS Responds to Oxidative Stress and Negatively Regulates Expression of the Catalase-Peroxidase Gene

    Li, Yuqing; He, Zheng-Guo

    2012-01-01

    Protection against oxidative stress is one of the primary defense mechanisms contributing to the survival of Mycobacterium tuberculosis in the host. In this study, we provide evidence that OxyS, a LysR-type transcriptional regulator functions as an oxidative stress response regulator in mycobacteria. Overexpression of OxyS lowers expression of the catalase-peroxidase (KatG) gene in M. smegmatis. OxyS binds directly with the katG promoter region and a conserved, GC-rich T-N11-A motif for OxyS ...

  4. Molecular and Physiological Effects of Mycobacterial oxyR Inactivation

    Pagán-Ramos, Eileen; Master, Sharon S.; Pritchett, Christopher L.; Reimschuessel, Renate; Trucksis, Michele; Timmins, Graham S.; Deretic, Vojo

    2006-01-01

    The majority of slow-growing mycobacteria have a functional oxyR, the central regulator of the bacterial oxidative stress response. In contrast, this gene has been inactivated during the evolution of Mycobacterium tuberculosis. Here we inactivated the oxyR gene in Mycobacterium marinum, an organism used to model M. tuberculosis pathogenesis. Inactivation of oxyR abrogated induction of ahpC, a gene encoding alkylhydroperoxide reductase, normally activated upon peroxide challenge. The absence o...

  5. Flame extinction of oxy-syngas nonpremixed jet flames

    Ranga Dinesh, K. K. J.; Luo, K.H.; van Oijen, J. A.

    2014-01-01

    Interest in carbon capture relevant to syngas based oxy-fuel combustion has inspired an extension of the high-resolution direct numerical simulation (DNS) to investigate the comprehensive nature of oxy-syngas combustion. The current research was motivated by two observations: (1) the local flame extinction of CO2-diluted oxy-syngas combustion has not been fully understood; (2) there is a lack of high resolution numerical data to gain new physical insights and to facilitate model development f...

  6. OxyContin: Prescription Drug Abuse. CSAT Advisory.

    Substance Abuse and Mental Health Services Administration (DHHS/PHS), Rockville, MD. Center for Substance Abuse Treatment.

    Recently, the media have issued numerous reports about the apparent increase in OxyContin abuse and addiction. OxyContin has been heralded as a miracle drug that allows patients with chronic pain to resume a normal life. It has also been called pharmaceutical heroin and is thought to have been responsible for a number of deaths and robberies in…

  7. Advanced modeling of oxy-fuel combustion of natural gas

    Chungen Yin

    2011-01-15

    The main goal of this small-scale project is to investigate oxy-combustion of natural gas (NG) through advanced modeling, in which radiation, chemistry and mixing will be reasonably resolved. 1) A state-of-the-art review was given regarding the latest R and D achievements and status of oxy-fuel technology. The modeling and simulation status and achievements in the field of oxy-fuel combustion were also summarized; 2) A computer code in standard c++, using the exponential wide band model (EWBM) to evaluate the emissivity and absorptivity of any gas mixture at any condition, was developed and validated in detail against data in literature. A new, complete, and accurate WSGGM, applicable to both air-fuel and oxy-fuel combustion modeling and applicable to both gray and non-gray calculation, was successfully derived, by using the validated EWBM code as the reference mode. The new WSGGM was implemented in CFD modeling of two different oxy-fuel furnaces, through which its great, unique advantages over the currently most widely used WSGGM were demonstrated. 3) Chemical equilibrium calculations were performed for oxy-NG flame and air-NG flame, in which dissociation effects were considered to different degrees. Remarkable differences in oxy-fuel and air-fuel combustion were revealed, and main intermediate species that play key roles in oxy-fuel flames were identified. Different combustion mechanisms are compared, e.g., the most widely used 2-step global mechanism, refined 4-step global mechanism, a global mechanism developed for oxy-fuel using detailed chemical kinetic modeling (CHEMKIN) as reference. 4) Over 15 CFD simulations were done for oxy-NG combustion, in which radiation, chemistry, mixing, turbulence-chemistry interactions, and so on were thoroughly investigated. Among all the simulations, RANS combined with 2-step and refined 4-step mechanism, RANS combined with CHEMKIN-based new global mechanism for oxy-fuel modeling, and LES combined with different combustion

  8. Chemistry and radiation in oxy-fuel combustion

    Yin, Chungen; Rosendahl, Lasse; Kær, Søren Knudsen

    2011-01-01

    In order to investigate the role of combustion chemistry and radiation heat transfer in oxy-fuel combustion modeling, a computational fluid dynamics (CFD) modeling study has been performed for two different oxy-fuel furnaces. One is a lab-scale 0.8MW oxy-natural gas flame furnace whose detailed in......-flame measurement data are available; the other is a conventional 609MW utility boiler which is assumed to be operating under oxy-fuel combustion condition with dry flue gas recycle. A new model for gaseous radiative properties is developed, validated, and then implemented in the CFD simulations. The CFD results...... simulations, from which significant difference in the predicted flame temperature and species is observed. This difference is consistent with those expected from the equilibrium calculation results. As a conclusion, the appropriate combustion mechanisms applicable to oxy-fuel combustion modeling are...

  9. Enthalpy Calculation for Pressurized Oxy- coal Combustion

    Weihong Wu; Jingli Huang

    2012-01-01

    Oxy-fuel combustion is recognizing one of the most promising available technologies that zero emission accomplishment may be in the offing. With coal burned under the pressure of 6MPa and oxygen-enriched conditions, the high temperature and high pressure gaseous combustion product is composed of 95% CO2 and water-vapor, with the rest of O2, N2 and so on. However, once lauded as classic approach of resolving fuel gas enthalpy calculation pertaining to ideal gas at atmospheric pressure was rest...

  10. Oxy-combustion for gas turbine applications

    Jordi Ollero, Eva

    2010-01-01

    Faced with the increasing concern about the effect of greenhouse gases in global warming, Carbon Capture and Storage technologies are developed. Oxy-combustion is one of these techniques; it consists of separating the nitrogen from the air and using the O2 (diluted in CO2) as an oxidant so that the resulting flue gases are mainly composed by carbon dioxide and water vapour and the capture of CO2 can be done easily after condensing the steam. Changing the working fluid from air to O2/CO2 modif...

  11. Control issues in oxy-fuel combustion

    Snarheim, Dagfinn

    2009-08-15

    Combustion of fossil fuels is the major energy source in todays society. While the use of fossil fuels is a necessity for our society to function, there has been an increasing concern on the emissions of CO{sub 2} resulting from human activities. Emissions of CO{sub 2} are considered to be the main cause for the global warming and climate changes we have experienced in recent years. To fight the climate changes, the emissions of CO{sub 2} must be reduced in a timely fashion. Strategies to achieve this include switching to less carbon intensive fuels, renewable energy sources, nuclear energy and combustion with CO{sub 2} capture. The use of oxy-fuel combustion is among the alternative post- and pre combustion capture concepts, a strategy to achieve power production from fossil fuels with CO{sub 2} capture. In an oxy-fuel process, the fuel is burned in a mixture of oxygen and CO{sub 2} (or steam), leaving the exhaust consisting mainly of CO{sub 2} and steam. The steam can be removed by use of a condenser, leaving (almost) pure CO{sub 2} ready to be captured. The downside to CO{sub 2} capture is that it is expensive, both in capital cost of extra equipment, and in operation as it costs energy to capture the CO{sub 2}. Thus it is important to maximize the efficiency in such plants. One attractive concept to achieve CO{sub 2} capture by use of oxy-fuel, is a semi-closed oxy-fuel gas turbine cycle. The dynamics of such a plant are highly integrated, involving energy and mass recycle, and optimizing efficiency might lead to operational (control) challenges. In these thesis we investigate how such a power cycle should be controlled. By looking at control at such an early stage in the design phase, it is possible to find control solutions otherwise not feasible, that leads to better overall performance. Optimization is used on a nonlinear model based on first principles, to compare different control structures. Then, closed loop simulations using MPC, are used to validate

  12. Oxy-Hydrogen Flame for Cutting of Steels

    Tušek, J.

    2007-01-01

    Full Text Available The paper deals with oxy-hydrogen cutting of steel plates. The first part deals with calculation of the combustion efficiency of an oxy-hydrogen flame. A device for supply of a hydrogen-oxygen mixture is described. The main part of the paper is focused on oxy-hydrogen cutting and its advantages. The main conclusions show that the cut surface is flat and very smooth, the heat-affected zone is very narrow, and the cutting speed is relatively high.

  13. Structures of the Porphyromonas gingivalis OxyR regulatory domain explain differences in expression of the OxyR regulon in Escherichia coli and P. gingivalis

    Differences in OxyR regulated expression of oxidative stress genes between Escherichia coli and Porphyromonas gingivalis are explained by very minor differences in structure and amino-acid sequence of the respective oxidized and reduced OxyR regulatory domains. These differences affect OxyR quaternary structures and are predicted from model building of full length OxyR–DNA complexes to confer distinct modes of DNA binding on this transcriptional regulator. OxyR transcriptionally regulates Escherichia coli oxidative stress response genes through a reversibly reducible cysteine disulfide biosensor of cellular redox status. Structural changes induced by redox changes in these cysteines are conformationally transmitted to the dimer subunit interfaces, which alters dimer and tetramer interactions with DNA. In contrast to E. coli OxyR regulatory-domain structures, crystal structures of Porphyromonas gingivalis OxyR regulatory domains show minimal differences in dimer configuration on changes in cysteine disulfide redox status. This locked configuration of the P. gingivalis OxyR regulatory-domain dimer closely resembles the oxidized (activating) form of the E. coli OxyR regulatory-domain dimer. It correlates with the observed constitutive activation of some oxidative stress genes in P. gingivalis and is attributable to a single amino-acid insertion in P. gingivalis OxyR relative to E. coli OxyR. Modelling of full-length P. gingivalis, E. coli and Neisseria meningitidis OxyR–DNA complexes predicts different modes of DNA binding for the reduced and oxidized forms of each

  14. Modeling of large-scale oxy-fuel combustion processes

    Yin, Chungen

    2012-01-01

    Quite some studies have been conducted in order to implement oxy-fuel combustion with flue gas recycle in conventional utility boilers as an effective effort of carbon capture and storage. However, combustion under oxy-fuel conditions is significantly different from conventional air-fuel firing....... The simulation results show that the gray and non-gray calculations of the same oxy-fuel WSGGM make distinctly different predictions in the wall radiative heat transfer, incident radiative flux, radiative source, gas temperature and species profiles. In relative to the non-gray implementation, the gray...... calculation of the oxy-fuel WSGGM remarkably over-predicts the radiative heat transfer to the furnace walls and under-predicts the gas temperature at the furnace exit plane, which also result in a higher incomplete combustion in the gray calculation. Moreover, the gray and non-gray calculations of the same...

  15. The oligomerization of OxyR in Escherichia coli

    Knapp, Gwendowlyn S; Tsai, Jerry W.; Hu, James C.

    2009-01-01

    We examine the contribution of residues at the dimer interface of the transcriptional regulator OxyR to oligomerization. Residues in contact across the dimer interface of OxyR were identified using the program Quaternary Contacts (QContacts). Site-directed mutagenesis was performed on the non-alanine or glycine residues identified in the resultant contact profile and the oligomerization ability of the mutant proteins was tested using the λcI repressor system to identify residues that are hot ...

  16. Oxy-Fuel Combustion of Coal

    Brix, Jacob

    model and experiments is caused by an experimental delay in ignition that is not captured by the model. Though this causes a deviation in total conversion COCOMO still predicts conversion rates accurately after ignition. A laboratory scale Fixed Bed Reactor (FBR), operated isothermally at 1073 K, has......This Ph.D. thesis describes an experimental and modeling investigation of the thermal conversion of coal and an experimental investigation of the emission of NO from char combustion in O2/N2 and O2/CO2 atmospheres. The motivation for the work has been the prospective use of the technology “Oxy......-Fuel Combustion” as a mean of CO2 abatement in large scale energy conversion. Entrained Flow Reactor (EFR) experiments have been conducted in O2/N2 and O2/CO2 mixtures in the temperature interval 1173 K – 1673 K using inlet O2 concentrations between 5 – 28 vol. %. Bituminous coal has been used as fuel in all...

  17. Steam-moderated oxy-fuel combustion

    The objective of the present paper is to propose a new variant of the oxy-fuel combustion for carbondioxide (CO2) sequestration in which steam is used to moderate the flame temperature. In this process, pure oxygen is mixed with steam and the resulting oxidant mixture is sent to the boiler for combustion with a fossil fuel. The advantage of this method is that flue gas recirculation is avoided and the volumetric flow rates through the boiler and auxiliary components is reduced by about 39% when compared to the conventional air-fired coal combustion power plant leading to a reduction in the size of the boiler. The flue gas, after condensation of steam, consists primarily of CO2 and can be sent directly for compression and sequestration. Flame structure analysis has been carried out using a 325-step reaction mechanism of methane-oxidant combustion to determine the concentration of oxygen required to ensure a stable flame. Thermodynamic exergy analysis has also been carried out on SMOC-operated CO2 sequestration power plant and air-fired power plant, which shows that though the gross efficiency increases the absolute power penalty of ∼8% for CO2 sequestration when compared to air-fired power plant.

  18. Enthalpy Calculation for Pressurized Oxy- coal Combustion

    Weihong Wu

    2012-08-01

    Full Text Available Oxy-fuel combustion is recognizing one of the most promising available technologies that zero emission accomplishment may be in the offing. With coal burned under the pressure of 6MPa and oxygen-enriched conditions, the high temperature and high pressure gaseous combustion product is composed of 95% CO2 and water-vapor, with the rest of O2, N2 and so on. However, once lauded as classic approach of resolving fuel gas enthalpy calculation pertaining to ideal gas at atmospheric pressure was restrained by pressure limitations. In this paper, the flue gas was assumed by an ideal mixture of four real gases system, and the equations for calculating the flue gas enthalpy were derived by using the cofunction method incorporating with the Dalton’s law of pressure summation based on the Virial equation. Consequently, the results showed that the calculation method on the basis of the Dalton’s law of pressure summation appears to be a reasonable enthalpy values for the 6MPa oxygen-enriched coal combustion as opposed to the inferior cofunction method.

  19. The ferrous-oxy complex of human aromatase

    In this communication, we document the self-assembly of heterologously expressed truncated human aromatase (CYP19) into nanometer scale phospholipids bilayers (Nanodiscs). The resulting P450 CYP19 preparation is stable and can tightly associate with the substrate androstenedione to form a nearly complete high-spin ferric protein. Ferrous CYP19 in Nanodiscs was mixed anaerobically in a rapid-scan stopped-flow with atmospheric dioxygen and the formation of the ferrous-oxy complex observed. First order decay of the oxy-complex to release superoxide and regenerate the ferric enzyme was monitored kinetically. Surprisingly, the ferrous-oxy complex of aromatase is more stable than that of hepatic CYP3A4, opening the path to precisely determine the biochemical and biophysical properties of the reaction cycle intermediates in this important human drug target

  20. Characteristics of oxy-fuel combustion in gas turbines

    Highlights: → Basic characteristics of oxy-fuel combustion in gas turbine conditions were studied. → The study was based on detailed chemical kinetics and thermodynamic calculations. → Critical O2/CO2 ratio for combustion stability and quenching was obtained. → Effect of inlet pressure on the combustion stability and quenching was examined. → Feasible oxy-fuel operation domain under gas turbine conditions was investigated. -- Abstract: This paper reports on a numerical study of the thermodynamic and basic combustion characteristics of oxy-fuel combustion in gas turbine related conditions using detailed chemical kinetic and thermodynamic calculations. The oxy-fuels considered are mixtures of CH4, O2, CO2 and H2O, representing natural gas combustion under nitrogen free gas turbine conditions. The GRI Mech 3.0 chemical kinetic mechanism, consisting of 53 species and 325 reactions, is used in the chemical kinetic calculations. Two mixing conditions in the combustion chambers are considered; a high intensity turbulence mixing condition where the combustion chamber is assumed to be a well-stirred reactor, and a typical non-premixed flame condition where chemical reactions occur in thin flamelets. The required residence time in the well-stirred reactor for the oxidation of fuels is simulated and compared with typical gas turbine operation. The flame temperature and extinction conditions are determined for non-premixed flames under various oxidizer inlet temperature and oxidizer compositions. It is shown that most oxy-fuel combustion conditions may not be feasible if the fuel, oxygen and diluent are not supplied properly to the combustors. The numerical calculations suggest that for oxy-fuel combustion there is a range of oxygen/diluent ratio within which the flames can be not only stable, but also with low remaining oxygen and low emission of unburned intermediates in the flue gas.

  1. Oxy-fuel combustion of coal and biomass blends

    Riaza Benito, Juan; Gil Matellanes, María Victoria; Álvarez González, Lucía; Pevida García, Covadonga; Pis Martínez, José Juan; Rubiera González, Fernando

    2012-01-01

    The ignition temperature, burnout and NO emissions of blends of a semi-anthracite and a high-volatile bituminous coal with 10 and 20 wt.% of olive waste were studied under oxy-fuel combustion conditions in an entrained flow reactor (EFR). The results obtained under several oxy-fuel atmospheres (21%O2–79%CO2, 30%O2–70%CO2 and 35%O2–65%CO2) were compared with those attained in air. The results indicated that replacing N2 by CO2 in the combustion atmosphere with 21% of O2 caused an increase in t...

  2. Low volatile coal combustion under oxy-fuel atmosphere

    Gómez Borrego, Ángeles; Álvarez Rodríguez, Diego; Fernández Domínguez, Isabel; Ballesteros, Juan Carlos; Menéndez López, Rosa M.ª

    2007-01-01

    One of the ways to face the abatement of CO2 emissions in power plants is the combustion of coal using oxy-fuel technology. In this case coal would be burned in a O2/CO2 atmosphere and the flue gas would consist mainly of CO2 which could be more easily confined. Most of the work related to oxyfuel combustion has been applied to high volatile coals. In this study run of mine and single seam coals ranging in the anthracite rank interval have been burned under oxy-fuel combustion conditions. ...

  3. Sensitivity analysis of oxy-fuel power plant system

    Highlights: • The half-dry mode of flue gas provides the highest efficiency for coal oxy-firing. • Air leakage exerts the largest impact on the net efficiency of oxy-coal process. • Utilizing the thermal energy of hot flue gas can improve process efficiency. - Abstract: A comprehensive sensitivity analyses has been conducted to assess the performance of a purpose-designed 600 MW supercritical steam oxy-fuel bituminous coal-fired power plant system, which includes three modes for the recirculation of flue gas (RFG), i.e. dry, half-dry and wet. The assessment was conducted by considering the changes to eight major operating parameters, the flue gas acid dew point, and the fuel consumption rate. Optimization of the system was also considered to minimize the energy loss of the oxy-fuel process. The results suggest that air leakage exerts the largest impact on the output of the system. The half-dry RFG oxy-fuel system is the most practical due to its high efficiency and easiness in operation, compared with the other two flue gas recirculation modes. The acid dew point of the half-dry RFG system is about 10 °C higher than that of the dry RFG system and approximately 5 °C lowers than the wet RFG system. For the optimization purpose, the improvement in the turbine system through utilizing the thermal energy of the hot flue gas is of prime importance. By heating the feed water at the outlet of the secondary feed water heater upstream of the deaerator and cooling down the hot flue gas to a temperature which is 10 °C above its acid dew point, the net efficiency of an oxy-fuel process can raise by around 1.0%, which narrows the energy penalty to less than 10% compared to the reference air-firing system. This is smaller than an energy penalty of around 12% for the oxy-fuel process without the recovery of heat in the hot flue gas. It is also found that the efficiency elevation through the thermal integration with turbine system is greater for the wet model than the

  4. Endogenous protein S-Nitrosylation in E. coli: regulation by OxyR.

    Seth, Divya; Hausladen, Alfred; Wang, Ya-Juan; Stamler, Jonathan S

    2012-04-27

    Endogenous S-nitrosylation of proteins, a principal mechanism of cellular signaling in eukaryotes, has not been observed in microbes. We report that protein S-nitrosylation is an obligate concomitant of anaerobic respiration on nitrate in Escherichia coli. Endogenous S-nitrosylation during anaerobic respiration is controlled by the transcription factor OxyR, previously thought to operate only under aerobic conditions. Deletion of OxyR resulted in large increases in protein S-nitrosylation, and S-nitrosylation of OxyR induced transcription from a regulon that is distinct from the regulon induced by OxyR oxidation. Furthermore, products unique to the anaerobic regulon protected against S-nitrosothiols, and anaerobic growth of E. coli lacking OxyR was impaired on nitrate. Thus, OxyR serves as a master regulator of S-nitrosylation, and alternative posttranslational modifications of OxyR control distinct transcriptional responses. PMID:22539721

  5. The development of an OxyHb animal model in mice and the study on OxyHb-induced apoptosis of mouse brain cells in vivo

    2008-01-01

    Objective On the basis of developing a new animal model for oxyhemoglobin(OxyHb)injection into subarachnoid space in mice,this research was to explore the temporal dependence and spatial distribution of OxyHb-induced apoptosis in the mouse brain cells in vivo and the mechanism of neurocyte injury induced by OxyHb.Methods The animal model for OxyHb injection into subarachnoid space in mice was developed.Mice were divided randomly into the experimental group(n=40)and the control group(n=35).The control group ...

  6. Optimization of Pressurized Oxy4Combustion with Flameless Reactor

    Malavasi, Massimo; Landegger, Gregory

    2014-06-30

    Pressurized OxyECombustion is one of the most promising technologies for utilityEscale power generation plants. Benefits include the ability to burn low rank coal and capture C02. By increasing the flue gas pressure during this process, greater efficiencies are derived from increased quantity and quality of thermal energy recovery. UPA with modeling support from MIT and testing and data verification by Georgia Tech’s Research Center designed and built a 100kW system capable of demonstrating pressurized oxyEcombustion using a flameless combustor. Wyoming PRB coal was run at 15 and 32 bar. Additional tests were not completed but sampled data demonstrated the viability of the technology over a broader range of operating pressures, Modeling results illustrated a flat efficiency curve over 20 bar, with optimum efficiency achieved at 29 bar. This resulted in a 33% (HHV) efficiency, a 5 points increase in efficiency versus atmospheric oxyEcombustion, and a competitive cost of electricity plus greater C02 avoidance costs then prior study’s presented. UPA’s operation of the benchEscale system provided evidence that key performance targets were achieved: flue gas sampled at the combustor outlet had nonE detectable residual fly ashes, and low levels of SO3 and heavyEmetal. These results correspond to prior pressurized oxyEcombustion testing completed by IteaEEnel.

  7. Oxy-RVAD: rescue in pulmonary complications after LVAD implantation.

    Mohite, P N; Sabashnikov, A; De Robertis, F; Popov, A F; Simon, A R

    2015-10-01

    Pulmonary complications after left ventricular assist device (LVAD) implantation seldom occur; however, if present, they may prove catastrophic. An Oxy-RVAD (oxygenator in right VAD circuit) is a lifesaving technique in such cases and allows freedom of introducing and removing an oxygenator into the RVAD circuit without opening the chest and competing with LVAD flow. PMID:25538179

  8. Oxy-gasoline torch. Innovative technology summary report

    NONE

    1998-12-01

    Under the deactivation and decommissioning (D and D) Implementation Plan of the US Department of Energy`s (DOE) Fernald Environmental Management Project (FEMP), non-recyclable process components and debris that are removed from buildings undergoing D and D are disposed of in an on-site disposal facility (OSDF). Critical to the design and operation of the FEMP`s OSDF are provisions to protect against subsidence of the OSDF`s cap. Subsidence of the cap could occur if void spaces within the OSDF were to collapse under the overburden of debris and the OSDF cap. Subsidence may create significant depressions in the OSDF`s cap in which rainwater could collect and eventually seep into the OSDF. To minimize voids in the FEMP`s OSDF, large metallic components are cut into smaller segments that can be arranged more compactly when placed in the OSDF. Component segmentation using an oxy-acetylene cutting torch was the baseline approach used by the FEMP`s D and D contractor on Plant 1, Babcock and Wilcox (B and W) Services, Inc., for the dismantlement and size-reduction of large metal components. Although this technology has performed satisfactorily, improvements are sought in the areas of productivity, airborne contamination, safety, and cost. This demonstration investigated the feasibility of using an oxy-gasoline torch as an alternative to the baseline oxy-acetylene torch for segmenting D and D components. This report provides a comparative analysis of the cost and performance of the baseline oxy-acetylene torch currently used by B and W Services, Inc., and the innovative oxy-gasoline torch.

  9. Oxy-fuel combustion of coal and biomass blends

    The ignition temperature, burnout and NO emissions of blends of a semi-anthracite and a high-volatile bituminous coal with 10 and 20 wt.% of olive waste were studied under oxy-fuel combustion conditions in an entrained flow reactor (EFR). The results obtained under several oxy-fuel atmospheres (21%O2–79%CO2, 30%O2–70%CO2 and 35%O2–65%CO2) were compared with those attained in air. The results indicated that replacing N2 by CO2 in the combustion atmosphere with 21% of O2 caused an increase in the temperature of ignition and a decrease in the burnout value. When the O2 concentration was increased to 30 and 35%, the temperature of ignition was lower and the burnout value was higher than in air conditions. A significant reduction in ignition temperature and a slight increase in the burnout value was observed after the addition of biomass, this trend becoming more noticeable as the biomass concentration was increased. The emissions of NO during oxy-fuel combustion were lower than under air-firing. However, they remained similar under all the oxy-fuel atmospheres with increasing O2 concentrations. Emissions of NO were significantly reduced by the addition of biomass to the bituminous coal, although this effect was less noticeable in the case of the semi-anthracite. -- Highlights: ► Coal and biomass blends combustion behaviour evaluated under oxy-fuel conditions. ► Biomass addition had a greater effect on the ignition temperature than on burnout. ► Lower NO emissions by blending olive waste with a bituminous coal.

  10. Oxy-gasoline torch. Innovative technology summary report

    Under the deactivation and decommissioning (D and D) Implementation Plan of the US Department of Energy's (DOE) Fernald Environmental Management Project (FEMP), non-recyclable process components and debris that are removed from buildings undergoing D and D are disposed of in an on-site disposal facility (OSDF). Critical to the design and operation of the FEMP's OSDF are provisions to protect against subsidence of the OSDF's cap. Subsidence of the cap could occur if void spaces within the OSDF were to collapse under the overburden of debris and the OSDF cap. Subsidence may create significant depressions in the OSDF's cap in which rainwater could collect and eventually seep into the OSDF. To minimize voids in the FEMP's OSDF, large metallic components are cut into smaller segments that can be arranged more compactly when placed in the OSDF. Component segmentation using an oxy-acetylene cutting torch was the baseline approach used by the FEMP's D and D contractor on Plant 1, Babcock and Wilcox (B and W) Services, Inc., for the dismantlement and size-reduction of large metal components. Although this technology has performed satisfactorily, improvements are sought in the areas of productivity, airborne contamination, safety, and cost. This demonstration investigated the feasibility of using an oxy-gasoline torch as an alternative to the baseline oxy-acetylene torch for segmenting D and D components. This report provides a comparative analysis of the cost and performance of the baseline oxy-acetylene torch currently used by B and W Services, Inc., and the innovative oxy-gasoline torch

  11. Rats

    Alexey Kondrashov

    2012-01-01

    Full Text Available We aimed to perform a chemical analysis of both Alibernet red wine and an alcohol-free Alibernet red wine extract (AWE and to investigate the effects of AWE on nitric oxide and reactive oxygen species production as well as blood pressure development in normotensive Wistar Kyoto (WKY and spontaneously hypertensive rats (SHRs. Total antioxidant capacity together with total phenolic and selected mineral content was measured in wine and AWE. Young 6-week-old male WKY and SHR were treated with AWE (24,2 mg/kg/day for 3 weeks. Total NOS and SOD activities, eNOS and SOD1 protein expressions, and superoxide production were determined in the tissues. Both antioxidant capacity and phenolic content were significantly higher in AWE compared to wine. The AWE increased NOS activity in the left ventricle, aorta, and kidney of SHR, while it did not change NOS activity in WKY rats. Similarly, increased SOD activity in the plasma and left ventricle was observed in SHR only. There were no changes in eNOS and SOD1 expressions. In conclusion, phenolics and minerals included in AWE may contribute directly to increased NOS and SOD activities of SHR. Nevertheless, 3 weeks of AWE treatment failed to affect blood pressure of SHR.

  12. A Reduced Order Model for the Design of Oxy-Coal Combustion Systems

    Steven L. Rowan; Celik, Ismail B.; Gutierrez, Albio D.; Jose Escobar Vargas

    2015-01-01

    Oxy-coal combustion is one of the more promising technologies currently under development for addressing the issues associated with greenhouse gas emissions from coal-fired power plants. Oxy-coal combustion involves combusting the coal fuel in mixtures of pure oxygen and recycled flue gas (RFG) consisting of mainly carbon dioxide (CO2). As a consequence, many researchers and power plant designers have turned to CFD simulations for the study and design of new oxy-coal combustion power plants, ...

  13. A fundamental study of biomass oxy-fuel combustion and co-combustion

    Farrow, Timipere Salome

    2013-01-01

    While oxy-fuel combustion research is developing and large scale projects are proceeding, little information is available on oxy-biomass combustion and cocombustion with coal. To address this knowledge gap, this research conducted has involved comprehensive laboratory based fundamental investigation of biomass firing and co-firing under oxy-fuel conditions and compared it to conventional air firing conditions. First, TGA was employed to understand the fundamental behaviour of biomass devolati...

  14. Susceptibilities of oxyR regulon mutants of Escherichia coli and Salmonella typhimurium to isoniazid.

    Rosner, J. L.

    1993-01-01

    Escherichia coli and Salmonella typhimurium are normally resistant to > 500 micrograms of the antituberculosis drug isonicotinic acid hydrazide (isoniazid; INH) per ml. Susceptibility to INH (< 50 micrograms/ml) has now been found for mutants that are deficient in OxyR, the oxidative stress response regulator. Two OxyR-regulated enzymes, alkyl hydroperoxide reductase and hydroperoxidase I, were identified as playing important roles in INH resistance. OxyR regulon mutants should be useful for ...

  15. Fireside Corrosion in Oxy-fuel Combustion of Coal

    Holcomb, Gordon R [National Energy Technology Laboratory; Tylczak, Joseph [National Energy Technology Laboratory; Meier, Gerald H [University of Pittsburgh; Lutz, Bradley [University of Pittsburgh; Jung, Keeyoung [Institute of Industrial Science and Technology, Korea; Mu, Nan; Yanar, Nazik M [University of Pittsburgh; Pettit, Frederick S [University of Pittsburgh; Zhu, Jingxi [Carnegie Mellon University; Wise, Adam [Carnegie Mellon University; Laughlin, David E. [Carnegie Mellon University; Sridhar, Seetharaman [Carnegie Mellon University

    2013-11-25

    Oxy-fuel combustion is burning a fuel in oxygen rather than air for ease of capture of CO2 from for reuse or sequestration. Corrosion issues associated with the environment change (replacement of much of the N2 with CO2 and higher sulfur levels) from air- to oxy-firing were examined. Alloys studied included model Fe–Cr alloys and commercial ferritic steels, austenitic steels, and nickel base superalloys. The corrosion behavior is described in terms of corrosion rates, scale morphologies, and scale/ash interactions for the different environmental conditions. Evidence was found for a hreshold for severe attack between 10-4 and 10-3 atm of SO3 at 700ºC.

  16. Representations of OxyContin in North American Newspapers and Medical Journals

    Whelan, Emma; Asbridge, Mark; Haydt, Susan

    2011-01-01

    Following the approval of OxyContin (Purdue Pharma, Canada) for medical use, the media began to report the use of OxyContin as a street drug, representing the phenomenon as a social problem. Meanwhile, the pain medicine community has criticized the inaccurate and one-sided media coverage of the OxyContin problem. The authors of this study aimed to contribute to an understanding of both sides of this controversy by analyzing the coverage of OxyContin in newspapers and medical journals. The ana...

  17. The scalar structure of turbulent oxy-fuel non-premixed flames

    Ranga Dinesh, K. K. J.; Richardson, E. S.; van Oijen, J. A.; Luo, K.H.; Jiang, X.

    2014-01-01

    This study addresses the scalar structure of turbulent oxy-fuel syngas non-premixed jet flame in the context of direct numerical simulation (DNS) and detailed chemistry. The main objective is to identify the influence of the Reynolds number on oxy-fuel flame structure, and to clarify the differences of scalar structures between oxy-fuel syngas and syngas-air flames at a similar higher Reynolds number. Two oxy-syngas flames at Reynolds numbers of 3000 and 6000 and one syngas-air flame at Reyno...

  18. CO2 capture from oxy-fuel combustion power plants

    Hu, Yukun

    2011-01-01

    To mitigate the global greenhouse gases (GHGs) emissions, carbon dioxide (CO2) capture and storage (CCS) has the potential to play a significant role for reaching mitigation target. Oxy-fuel combustion is a promising technology for CO2 capture in power plants. Advantages compared to CCS with the conventional combustion technology are: high combustion efficiency, flue gas volume reduction, low fuel consumption, near zero CO2 emission, and less nitrogen oxides (NOx) formation can be reached sim...

  19. The dissociation of oxy-acids at elevated temperatures

    The heat capacities of dissociation for carbonic, bicarbonate, phosphoric, biphosphate, silicic, nitric, boric and bisulfate oxy-acids have been evaluated at temperatures up to 300 C using published dissociation constants, heat capacities and a model which explicitly accounts for both electrostatic and nonelectrostatic contributions to the thermodynamic properties of dissociation. The heat capacities calculated are independent of the entropies of dissociation or the chemical characteristics of the acids, and are the same for all acids of a given dissociation type (i.e. 1st, 2nd, etc.). The average deviation between measured and calculated log Ksub(T)'s is less than 0.05 log units in the temperature range from 25 to 300 C. Dissociation constants for acetic acid can be accurately calculated using the oxy-acid heat capacity expression. The heat capacities are used to calculate dissociation constants for the oxy-acids of Cr(VI), N(III), S(IV), S(II), Se(IV), Se(VI), As(III), As(V), Te(VI), Cl(I), Cl(III), I(V) and C1-C3 aliphatic acids to temperatures of 300 C. (author)

  20. Effect of oxy-combustion flue gas on mercury oxidation.

    Fernández-Miranda, Nuria; Lopez-Anton, M Antonia; Díaz-Somoano, Mercedes; Martínez-Tarazona, M Rosa

    2014-06-17

    This study evaluates the effect of the gases present in a typical oxy-coal combustion atmosphere on mercury speciation and compares it with the mercury speciation produced in conventional air combustion atmospheres. The work was performed at laboratory scale at 150 °C. It was found that the minor constituents (SO2, NOx, and HCl) significantly modify the percentages of Hg(2+) in the gas. The influence of these species on mercury oxidation was demostrated when they were tested individually and also when they were blended in different gas compositions, although the effect was different to the sum of their individual effects. Of the minor constituents, NOx were the main species involved in oxidation of mercury. Moreover, it was found that a large concentration of H2O vapor also plays an important role in mercury oxidation. Around 50% of the total mercury was oxidized in atmospheres with H2O vapor concentrations typical of oxy-combustion conditions. When the atmospheres have similar concentrations of SO2, NO, NO2, HCl, and H2O, the proportion of Hg(0)/Hg(2+) is similar regardless of whether CO2 (oxy-fuel combustion) or N2 (air combustion) are the main components of the gas. PMID:24877895

  1. Oxy-coal combustion in an entrained flow reactor: Application of specific char and volatile combustion and radiation models for oxy-firing conditions

    The deployment of oxy-fuel combustion in utility boilers is one of the major options for CO2 capture. However, combustion under oxy-firing conditions differs from conventional air-firing combustion, e.g., in the aspect of radiative heat transfer, coal conversion and pollutants formation. In this work, a numerical study on pulverised coal combustion was conducted to verify the applicability and accuracy of several sub-models refined for oxy-fuel conditions, e.g., gaseous radiative property model, gas-phase combustion mechanism and heterogeneous char reaction model. The sub-models were implemented in CFD (Computational Fluid Dynamics) simulations of combustion of three coals under air-firing and various oxy-firing (21–35% vol O2 in O2/CO2 mixture) conditions in an EFR (entrained flow reactor). The predicted coal burnouts and gaseous emissions were compared against experimental results. A good agreement between the simulations and experiments was achieved, indicating a good applicability and reliability of the refined sub-models and suitability of use of the experimentally derived kinetic data in coal devolatilisation and char oxidation sub-models. The sub-models and the practices implemented in this work can be used in large-scale oxy-fuel combustion processes for reliable design and optimization. - Highlights: • CFD (computational fluid dynamics) modelling predicted overall combustion and emissions under air- and oxy-firing conditions in an EFR. • Sub-models originally developed for air-firing were adapted for oxy-fuel combustion. • A very good agreement between simulation results and experimental data was achieved. • The refined JL 4-step global mechanism for gas-phase combustion improves flame temperature prediction. • Non-gray calculation of an appropriate oxy-fuel WSGGM is recommended to improve simulations of oxy-fuel combustion processes

  2. The OxyMask™ development and performance in healthy volunteers

    James E Paul

    2008-12-01

    Full Text Available James E Paul1, Horia Hangan2, Julius Hajgato31Department of Anesthesia, McMaster University, Hamilton, ON, Canada; 2Faculty of Engineering, The University of Western Ontario, London, ON, Canada; 3Southmedic Inc., Barrie, ON, CanadaBackground: The OxyMask™ is a unique, open-style, oxygen mask that was originally developed in 2005. The original mask was modified, using computational fluid dynamics numerical simulations, with the goal of allowing it to produce a wider range of FiO2. This analysis was used to guide the modification of the mask shell and the location for the oxygen diffuser.Methods: The new OxyMask was attached to 10 healthy subjects and used to deliver escalating levels of oxygen (1.5, 2, 2.5, 3, 5, 10, 15, 20, 25 and 30 LPM for 90 seconds at each level and the resulting FiO2 was recorded (at the lips from 5 consecutive measurements at each oxygen flow rate.Results: Mean FiO2 was 25.4% at 1.5 LPM of oxygen, 30.1% at 2 LPM, 36.5% at 2.5 LPM, 41.8% at 3 LPM, 57.6% at 5 LPM, 74.4% at 10 LPM, and 80.1% at 15 LPM. Each FiO2 achieved at these escalating oxygen levels was significantly greater than all the previous levels. The mean FiO2 was 82.8 at 20 LPM, 84.2% at 25 LPM and 84.3% at 30 LPM. All of these values on average were not significantly greater than the FiO2 achieved with 15 LPM. In a few subjects a maximum FiO2 of 90% was reached.Conclusion: The original OxyMask was successfully modified so that the second generation of the mask can provide a wide range of FiO2, from 25% to 90%, while keeping its unique open design.Keywords: oxygen, oxygen masks, oxygen therapy, OxyMask™, OxyArm™, clinical trial, computational fluid dynamics (CFD, equipment design, biomedical engineering

  3. Comprehensive investigation of process characteristics for oxy-steam combustion power plants

    Highlights: • Oxy-steam combustion exhibits better performance than oxy-CO2 combustion. • Cost of electricity in oxy-steam combustion is 6.62% less than oxy-CO2 combustion. • The increase of oxygen concentration in oxidant can improve its system performance. • The decrease of excess oxygen coefficient can be helpful for its system performance. • Integration with solar technology can enhance its thermodynamic performance. - Abstract: Oxy-steam combustion, as an alternative option of oxy-fuel combustion technology, is considered as a promising CO2 capture technology for restraining CO2 emissions from power plants. To attain its comprehensive process characteristics, process simulation, thermodynamic assessment, and sensitivity analysis for oxy-steam combustion pulverized-coal-fired power plants are investigated whilst its corresponding CO2/O2 recycled combustion (oxy-CO2 combustion) power plant is served as the base case for comparison. Techno-economic evaluation and integration with solar parabolic trough collectors are also discussed to justify its economic feasibility and improve its thermodynamic performance further, respectively. It is found that oxy-steam combustion exhibits better performance than oxy-CO2 combustion on both thermodynamic and economic aspects, in which the cost of electricity decreases about 6.62% whilst the net efficiency and exergy efficiency increase about 0.90 and 1.01 percentage points, respectively. The increment of oxygen concentration in oxidant (20–45 mol.%) and decrease of excess oxygen coefficient (1.01–1.09) in a certain range are favorable for improving oxy-steam combustion system performance. Moreover, its thermodynamic performance can be improved when considering solar parabolic trough collectors for heating recycled water, even though its cost of electricity increases about 2 $/(MW h)

  4. Oxy-coal combustion in an entrained flow reactor: Application of specific char and volatile combustion and radiation models for oxy-firing conditions

    Álvarez González, Lucía; Yin, C.; Riaza Benito, Juan; Pevida García, Covadonga; Pis Martínez, José Juan; Rubiera González, Fernando

    2013-01-01

    The deployment of oxy-fuel combustion in utility boilers is one of the major options for CO2 capture. However, combustion under oxy-firing conditions differs from conventional air-firing combustion, e.g., in the aspect of radiative heat transfer, coal conversion and pollutants formation. In this work, a numerical study on pulverised coal combustion was conducted to verify the applicability and accuracy of several sub-models refined for oxy-fuel conditions, e.g., gaseous radiative property mod...

  5. Conceptual Mean-Line Design of Single and Twin-Shaft Oxy-Fuel Gas Turbine in a Semiclosed Oxy-Fuel Combustion Combined Cycle

    Sammak, Majed; Thorbergsson, Egill; Grönstedt, Tomas; Genrup, Magnus

    2013-01-01

    The aim of this study was to compare single- and twin-shaft oxy-fuel gas turbines in a semiclosed oxy-fuel combustion combined cycle (SCOC–CC). This paper discussed the turbomachinery preliminary mean-line design of oxy-fuel compressor and turbine. The conceptual turbine design was performed using the axial through-flow code luax-t, developed at Lund University. A tool for conceptual design of axial compressors developed at Chalmers University was used for the design of the compressor. The mo...

  6. Oxy-coal combustion in an entrained flow reactor: Application of specific char and volatile combustion and radiation models for oxy-firing conditions

    Álvarez, L.; Yin, Chungen; Riaza, J.;

    2013-01-01

    The deployment of oxy-fuel combustion in utility boilers is one of the major options for CO2 capture. However, combustion under oxy-firing conditions differs from conventional air-firing combustion, e.g., in the aspect of radiative heat transfer, coal conversion and pollutants formation. In this...... work, a numerical study on pulverised coal combustion was conducted to verify the applicability and accuracy of several sub-models refined for oxy-fuel conditions, e.g., gaseous radiative property model, gas-phase combustion mechanism and heterogeneous char reaction model. The sub-models were...... implemented in CFD (Computational Fluid Dynamics) simulations of combustion of three coals under air-firing and various oxy-firing (21-35% vol O2 in O2/CO2 mixture) conditions in an EFR (entrained flow reactor). The predicted coal burnouts and gaseous emissions were compared against experimental results. A...

  7. Process simulation of oxy-combustion for maximization of energy output using ASPEN plus

    Subhodeep Banerjee, Xiao Zhang, Suraj K. Puvvada, Ramesh K. Agarwal

    2014-01-01

    Full Text Available Oxy-fuel combustion is a next-generation combustion technology that shows promise to address the need of low-cost carbon capture from fossil fueled power plants. Oxy-fuel combustion requires expensive pre-processing in an air separation unit to separate pure oxygen from air for the combustion process, which reduces the overall efficiency of the process. This paper employs ASPEN Plus process simulation software to model a simple oxy-fuel combustor and investigates the effect of various parameters on the energy output. The composition of the flue gas is carefully examined. The results of this study provide a starting point for optimized oxy-fuel combustion operation for maximum energy output, which will be crucial for future deployment of oxy-fuel combustion technology.

  8. Representations of OxyContin in North American Newspapers and Medical Journals

    Emma Whelan

    2011-01-01

    Full Text Available Following the approval of OxyContin (Purdue Pharma, Canada for medical use, the media began to report the use of OxyContin as a street drug, representing the phenomenon as a social problem. Meanwhile, the pain medicine community has criticized the inaccurate and one-sided media coverage of the OxyContin problem. The authors of this study aimed to contribute to an understanding of both sides of this controversy by analyzing the coverage of OxyContin in newspapers and medical journals. The analyses revealed inconsistent messages about the drug from physicians in the news media and in medical journals, which has likely contributed to the drug’s perception as a social problem. The authors suggest ways to address the lack of medical consensus surrounding OxyContin. The results of this study may help resolve the concerns and conflicts surrounding this drug and other opioids.

  9. Advanced Diagnostics in Oxy-Fuel Combustion Processes

    Brix, Jacob; Toftegaard, Maja Bøg; Clausen, Sønnik;

    in the sampling equipment. The use of the IR technique for determination of particle temperatures, particle sizes, and number density proved reliable in both the swirl burner and the laboratory scale fixed bed reactor. When the technique was used in the swirl burner the subsequent data treatment was......This report sums up the findings in PSO-project 010069, “Advanced Diagnostics in Oxy- Fuel Combustion Processes”. Three areas of optic diagnostics are covered in this work: - FTIR measurements in a 30 kW swirl burner. - IR measurements in a 30 kW swirl burner. - IR measurements in a laboratory...

  10. Biomass co-firing under oxy-fuel conditions

    Álvarez, L.; Yin, Chungen; Riaza, J.;

    2014-01-01

    This paper presents an experimental and numerical study on co-firing olive waste (0, 10%, 20% on mass basis) with two coals in an entrained flow reactor under three oxy-fuel conditions (21%O2/79%CO2, 30%O2/70%CO2 and 35%O2/65%CO2) and air–fuel condition. Co-firing biomass with coal was found to...... have favourable synergy effects in all the cases: it significantly improves the burnout and remarkably lowers NOx emissions. The reduced peak temperatures during co-firing can also help to mitigate deposition formation in real furnaces. Co-firing CO2-neutral biomass with coals under oxy-fuel conditions...... can achieve a below-zero CO2 emission if the released CO2 is captured and sequestered. The model-predicted burnout and gaseous emissions were compared against the experimental results. A very good agreement was observed, the differences in a range of ± 5–10% of the experimental values, which indicates...

  11. Pressurized oxy-coal combustion: Ideally flexible to uncertainties

    Simultaneous multi-variable gradient-based optimization with multi-start is performed on a 300 MWe wet-recycling pressurized oxy-coal combustion process with carbon capture and sequestration, subject to uncertainty in fuel, ambient conditions, and other input specifications. Two forms of flue gas thermal recovery are studied, a surface heat exchanger and a direct contact separation column. Optimization enables ideal flexibility in the processes: when changing the coal utilized, the performance is not compromised compared to the optimum performance of a process specifically designed for that coal. Similarly, the processes are immune to other uncertainties like ambient conditions, air flow, slurry water flow, atomizer stream flow and the oxidizer stream oxygen purity. Consequently, stochastic programming is shown to be unnecessary. Close to optimum design, the processes are also shown to be insensitive towards design variables such as the areas of the feedwater heaters. Recently proposed thermodynamic criteria are used as embedded design specifications in the optimization process, rendering it faster and more robust. - Highlights: • Proposed formulation to assess the flexibility of power generation processes facing uncertainties. • Obtained ideal flexibility of pressurized oxy-coal combustion with respect to coal type. • Performance of processes under uncertainty match performance of optimal processes for specific set of inputs. • Stochastic programming is not required and instead hierarchic optimization is utilized

  12. Response of substances co-expressed in hypothalamic magnocellular neurons to osmotic challenges in normal and Brattleboro rats

    Bundzikova, J.; Pirnik, Z.; Zelena, D.;

    2008-01-01

    hydromineral homeostasis. Maintenance of the body hydromineral balance depends on the coordinated action of principal biologically active compounds, AVP and OXY, synthesized in the hypothalamic supraoptic and paraventricular nuclei. However, on the regulation of water-salt balance, other substances, co...... better understood in non-osmotic than osmotic functional circuits. Brattleboro strain of rats that does not express functional vasopressin was also included in this review. These animals suffer from chronic hypernatremia and hyperosmolality, accompanied by sustained increase in OXY mRNA in PVN and SON...... and OXY levels in plasma. They represent an important model of animals with constantly sustained osmolality, which in the future, will be utilizable for revealing the physiological importance of biologically active substances co-expressed with AVP and OXY, involved in the regulation of plasma...

  13. The development of an OxyHb animal model in mice and the study on OxyHb-induced apoptosis of mouse brain cells in vivo

    Shi Wei; Wang Ruizhi; Huang Liyong; Sun Jianjun; Wang Fangru; Liu Chongxiao; Zhou Le; Guo Zhenyu; John H Zhang

    2008-01-01

    Objective On the basis of developing a new animal model for oxyhemoglobin (OxyHb) injection into subarachnoid space in mice, this research was to explore the temporal dependence and spatial distribution of OxyHb- induced apoptosis in the mouse brain cells in vivo and the mechanism of neurocyte injury induced by OxyHb. Methods The animal model for OxyHb injection into subarachnoid space in mice was developed. Mice were divided randomly into the experimental group (n=40) and the control group (n= 35). The control group received saline injection (50 μL ) and the experimental group received OxyHb injection (50 μL ), both into the subarachnoid space. The mice of the two groups were subdivided according to different postoperative time (3 h, 6 h, 12 h, 24 h and 48 h). The apoptosis or necrosis of cells was distinguished with microscopy (HE staining), transmission electron microscopy and TUNEL method. Results The distribution of apoptosis was mainly in the ipsilateral neocortex and bilateral hippocampal gyrus. The apoptotic mouse brain cells showed morphological changes in the experimental group by HE staining and transmission electron microscopy. The count of TUNEL-positive cells showed substantial increase in the experimental group, and there was a significant difference between the control and experimental groups, and the number of OxyHb- induced apoptotic cells decreased with time. Conclusion OxyHb in subarachnoid space in mice can induce apoptasis, but not necrosis of mouse brain cells in viro. The apoptotic brain cells show the pattern of temporal dependence and spatial distribution. It is suggested that the early treatment should be the method of first choice for treating the hemorrhagic brain injury.

  14. Process simulation of oxy-combustion for maximization of energy output using ASPEN plus

    Subhodeep Banerjee, Xiao Zhang, Suraj K. Puvvada, Ramesh K. Agarwal

    2014-01-01

    Oxy-fuel combustion is a next-generation combustion technology that shows promise to address the need of low-cost carbon capture from fossil fueled power plants. Oxy-fuel combustion requires expensive pre-processing in an air separation unit to separate pure oxygen from air for the combustion process, which reduces the overall efficiency of the process. This paper employs ASPEN Plus process simulation software to model a simple oxy-fuel combustor and investigates the effect of various paramet...

  15. OxyContin® as currency: OxyContin® use and increased social capital among rural Appalachian drug users.

    Jonas, Adam B; Young, April M; Oser, Carrie B; Leukefeld, Carl G; Havens, Jennifer R

    2012-05-01

    Studies have shown that position within networks of social relations can have direct implications on the health behaviors of individuals. The present study examines connections between drug use and individual social capital within social networks of drug users (n = 503) from rural Appalachian Kentucky, U.S.A. Respondent driven sampling was used to recruit individuals age 18 and older who had used one of the following drugs to get high: cocaine, crack, heroin, methamphetamine, or prescription opioids. Substance use was measured via self-report and social network analysis of participants' drug use network was used to compute effective size, a measure of social capital. Drug network ties were based on sociometric data on recent (past 6 month) drug co-usage. Multivariate multi-level ordinal regression was used to model the independent effect of socio-demographic and drug use characteristics on social capital. Adjusting for gender, income, and education, daily OxyContin(®) use was found to be significantly associated with greater social capital, and daily marijuana use was associated with less social capital. These results suggest that in regions with marked economic disparities such as rural Appalachia, OxyContin(®) may serve as a form of currency that is associated with increased social capital among drug users. Interventions focusing on increasing alternate pathways to acquiring social capital may be one way in which to alleviate the burden of drug use in this high-risk population. PMID:22465379

  16. Dynamic characteristics of Oxy-CFB combustion system based on Aspen%基于Aspen平台的Oxy-CFB燃烧侧动态特性模拟

    周建新; 邵壮; 李崇; 司风琪; 徐治皋

    2014-01-01

    Taking an oxy-fuel circulating fluidized bed (Oxy-CFB )combustor pilot facility as the simulation object,a steady-state model for the Oxy-CFB combustion system was built with the plat-form of Aspen Plus.After modifying the steady-state model for the dynamic process simulation,a new dynamic model for the combustion system was built based on Aspen Dynamics and the results were validated by the test data.The simulation study on the responses of the bed temperature and the components,including carbon dioxide,oxygen,carbon monoxide,and nitrogen monoxide in the flue gas,was carried out.The research results show that the dynamic model based on Aspen pro-vides a new method to investigate the dynamic characteristics of the Oxy-CFB combustion system. The dynamic response characteristics of bed temperature and gas components for the coal feed and primary air step changes can provide valuable information for design and implementation of the con-trol system of the Oxy-CFB combustion system.%以某循环流化床富氧燃烧中试系统为模拟对象,借助Aspen Plus流程模拟软件搭建了Oxy-CFB燃烧系统的稳态模型。在此基础上针对动态过程模拟进行改进,并利用Aspen Dynam-ics平台建立了该燃烧系统的动态模型,利用试验数据对模拟结果进行了验证。基于动态模型对Oxy-CFB床温以及燃烧排放产物中二氧化碳、氧气、一氧化碳、一氧化氮等进行了仿真研究。研究表明,基于Aspen平台的动态过程模拟为Oxy-CFB锅炉燃烧系统的动态特性分析提供了新的研究手段,模拟所得的床温及烟气各组分随给煤量、一次风量阶跃变化的动态响应规律可为今后Oxy-CFB燃烧系统的控制设计提供重要依据。

  17. Combustion Characteristics of Oxy-fuel Burners for CO2 Capturing Boilers

    Ahn, Joon; Kim, Hyouck Ju; Choi, Kyu Sung

    Oxy-fuel boilers have been developed to capture CO2 from the exhaust gas. A 50 kW class model burner has been developed and tested in a furnace type boiler. The burner has been scaled up to 0.5 and 3 MW class for fire-tube type boilers. The burners are commonly laid out in a coaxial type to effectively heat the combustion chamber of boilers. Burners are devised to support air and oxy-fuel combustion modes for the retrofitting scenario. FGR (flue gas recirculation) has been tried during the scale-up procedure. Oxy-fuel combustion yields stretched flame to uniformly heat the combustion chamber. It also provides the high CO2 concentration, which is over 90% in dry base. However, pure oxy-fuel combustion increases NO concentration, because of the reduced flow rate. The FGR can suppress the thermal NOx induced by the infiltration of the air.

  18. Plasma-enhanced growth, composition, and refractive index of silicon oxy-nitride films

    Mattsson, Kent Erik

    1995-01-01

    material is in a state of internal tension. The viscoelastic relaxation process for temperatures above 700 °C is dominated by the relaxation of this internal tension. A linear relation between the refractive index and material density is determined for silicon oxy-nitride with a nitrogen concentration......Secondary ion mass spectrometry and refractive index measurements have been carried out on silicon oxy-nitride produced by plasma-enhanced chemical vapor deposition (PECVD). Nitrous oxide and ammonia were added to a constant flow of 2% silane in nitrogen, to produce oxy-nitride films with atomic...... nitrogen concentrations between 2 and 10 at. %. A simple atomic valence model is found to describe both the measured atomic concentrations and published material compositions for silicon oxy-nitride produced by PECVD. A relation between the Si–N bond concentration and the refractive index is found. This...

  19. Nongray-gas Effects in Modeling of Large-scale Oxy-fuel Combustion Processes

    Yin, Chungen

    2012-01-01

    Quite some studies have been conducted in order to implement oxy-fuel combustion with flue gas recycle in conventional utility boilers as an effective effort of carbon capture and storage. However, combustion under oxy-fuel conditions is significantly different from conventional air-fuel firing......, in which a recently refined weighted-sum-of-gray-gases model (WSGGM) applicable to oxy-fuel conditions is used to perform non-gray and gray calculations, respectively, and a widely used air-fuel WSGGM is also employed for gray calculation. This makes the only difference among the different computational...... cases. The simulation results show that the gray and non-gray calculations of the same oxy-fuel WSGGM make distinctly different predictions in the wall radiative heat transfer, incident radiative flux, radiative source, gas temperature and species profiles. In relative to the non-gray implementation...

  20. Recovery Act: Oxy-Combustion Technology Development for Industrial-Scale Boiler Applications

    Levasseur, Armand

    2014-01-01

    This Topical Report outlines guidelines and key considerations for design and operation of pulverized coal-fired boilers for oxy-combustion. The scope addressed includes only the boiler island, not the entire oxy-fired CO{sub 2} capture plant. These guidelines are primarily developed for tangential-fired boilers and focus on designs capable of dual air and oxy-fired operation. The guidelines and considerations discussed are applicable to both new units and existing boiler retrofits. These guidelines are largely based on the findings from the extensive 15 MW{sub th} pilot testing and design efforts conducted under this project. A summary level description is provided for each major aspect of boiler design impacted by oxy-combustion, and key considerations are discussed for broader application to different utility and industrial designs. Guidelines address the boiler system arrangement, firing system, boiler thermal design, ducting, materials, control system, and other key systems.

  1. Ammonia chemistry in oxy-fuel combustion of methane

    Mendiara, Teresa; Glarborg, Peter

    2009-01-01

    The oxidation of NH3 during oxy-fuel combustion of methane, i.e., at high [CO2], has been studied in a flow reactor. The experiments covered stoichiometries ranging from fuel rich to very fuel lean and temperatures from 973 to 1773 K. The results have been interpreted in terms of an updated...... detailed chemical kinetic model. A high CO2 level enhanced formation of NO under reducing conditions while it inhibited NO under stoichiometric and lean conditions. The detailed chemical kinetic model captured fairly well all the experimental trends. According to the present study, the enhanced CO...... concentrations and alteration in the amount and partitioning of O/H radicals, rather than direct reactions between N-radicals and CO2, are responsible for the effect of a high CO2 concentration on ammonia conversion. When CO2 is present as a bulk gas, formation of NO is facilitated by the increased OH/H ratio...

  2. Advanced Diagnostics in Oxy-Fuel Combustion Processes

    Brix, Jacob; Toftegaard, Maja Bøg; Clausen, Sønnik; Jensen, Anker Degn

    2012-01-01

    Denne rapport beskriver resultaterne, der er blevet opnået i PSO-projektet 010069, “Advanced Diagnostics in Oxy-Fuel Combustion Processes”. Tre områder af optisk diagnostik er inkluderet i rapporten: - FTIR målinger i en 30 kW swirlbrænder. - IR målinger i en 30 kW swirlbrænder. - IR målinger i en laboratorieskala fixed bed reaktor. Resultaterne, der blev opnået i swirlbrænderen, viser at FTIR teknikken er et værdifuldt værktøj til bestemmelse af gasfasetemperaturer. Når dens anvendelighed ev...

  3. Characterization of high velocity oxy-fuel combustion sprayed hydroxyapatite.

    Haman, J D; Lucas, L C; Crawmer, D

    1995-02-01

    Bioceramic coatings, created by the high velocity oxy-fuel combustion spraying of hydroxyapatite (HA) powders onto commercially pure titanium, were characterized in order to determine whether this relatively new coating process can be successfully applied to bioceramic coatings of orthopaedic and dental implants. Fourier transform infrared spectroscopy, X-ray diffraction and scanning electron microscopy were used to characterize both the HA starting powders and coatings. A 12 wk immersion test was conducted and the resulting changes in the coatings were also characterized. Calcium ion release during dissolution was measured with flame atomic absorption during the first 6 weeks of the immersion study. A comparison of powder and coating X-ray diffraction patterns and lattice parameters revealed an HA-type coating with some loss in crystallinity. Fourier transform infrared results showed a partial loss of the OH- group during spraying, however the phosphate groups were still present. Scanning electron microscopy analysis showed a lamellar structure with very close coating-to-substrate apposition. The coatings experienced a loss of calcium during the immersion study, with the greatest release in calcium occurring during the first 6 days of the study. No significant structural or chemical changes were observed during the 12 wk immersion study. These results indicate that the high velocity oxy-fuel process can produce an HA-type coating; however, the process needs further optimization, specifically in the areas of coating-to-substrate bond strength and minimization of phases present other than HA, before it would be recommended for commercial use. PMID:7749000

  4. Numerical simulation of oxy-fuel combustion for gas turbine applications

    Relevant reduction on worldwide greenhouse gases emissions shall be based on more efficient power generation systems linked to a carbon capture and storage technology (CCS). Integrated gasification combined cycle and natural gas combined cycle (IGCC) would play an effective role to these objectives. To that, oxy-fuel combustion is an important alternative for the implementation of CCS technology, claiming, however, modifications to the conventional operation of gas turbines combustors. This work presents CFD simulations of oxy-fuel combustion in a can-type model gas turbine combustor. Equilibrium combustion model for non-premixed flames was used to model chemical reactions and turbulence was accounted for by Reynolds Stress Model (RSM). Numerical predictions were carried out after validating the numerical schemes and turbulence model. In addition to the baseline (propane/air combustion) four oxy-fuel cases were studied: propane and syngas oxy-fuel combustion with two different O2/CO2 ratios. The predictions showed that the propane/oxy-fuel flame (O2/CO2 = 1) resembles the baseline case (propane/air) though, with much higher temperature levels in the central core of the combustor, resulting in a poor gas turbine combustor pattern factor. The oxy-syngas flames showed intense reactions in the primary zone, before the first dilution holes, leading to a very good patter factor. The numerical model proposed for this study can be considered a relevant tool in the preliminary design phase of gas turbine combustors applied to CCS technology. - Highlights: • A gas turbine combustion chamber model was numerically simulated. • The numerical model was validated against experimental data for isothermal flow. • CCS technology based on oxy-fuel combustion for propane and syngas were studied. • The syngas cases showed improved pattern factors compared to the Propane/Air case. • The oxy-fuel combustion based on syngas seemed adequate for CCS technology

  5. Sulfide Stress Cracking and Electrochemical Corrosion of Precipitation Hardening Steel After Plasma Oxy-Nitriding

    Granda-Gutiérrez, E. E.; Díaz-Guillén, J. C.; Díaz-Guillén, J. A.; González, M. A.; García-Vázquez, F.; Muñóz, R.

    2014-11-01

    In this paper, we present the results of a duplex plasma nitriding followed by an oxidizing stage process (which is also referred as oxy-nitriding) on the corrosion behavior of a 17-4PH precipitation hardening stainless steel. The formation of both, expanded martensite (b.c.t. α'N-phase) and chromium oxide (type Cr2O3) in the subsurface of oxy-nitrided samples at specific controlled conditions, leads in a noticeable increasing in the time-to-rupture during the sulfide stress cracking test, in comparison with an untreated reference sample. Oxy-nitriding improves the corrosion performance of the alloy when it is immersed in solutions saturated by sour gas, which extends the application potential of this type of steel in the oil and gas extraction and processing industry. The presence of the oxy-nitrided layer inhibits the corrosion process that occurs in the near-surface region, where hydrogen is liberated after the formation of iron sulfides, which finally produces a fragile fracture by micro-crack propagation; the obtained results suggest that oxy-nitriding slows this process, thus delaying the rupture of the specimen. Moreover, oxy-nitriding produces a hard, sour gas-resistant surface, but do not significantly affect the original chloride ion solution resistance of the material.

  6. In vitro metabolism of the anti-androgenic fungicide vinclozolin by rat liver microsomes

    Vinclozolin (V) is a fungicide used in agricultural settings. V administered to rats is hydrolyzed to 2-[[(3,5-dichlorophenyl)-carbamoyl]oxy]-2-methyl-3-butenoic acid (Ml) and 3',5'-dichloro-2-hydroxy-2-methylbut-3-enanilide (M2). V, Ml and M2 have antiandrogenic properties by in...

  7. NO emissions in oxy-coal combustion with the addition of steam in an entrained flow reactor

    Álvarez González, Lucía; Riaza Benito, Juan; Gil Matellanes, María Victoria; Pevida García, Covadonga; Pis Martínez, José Juan; Rubiera González, Fernando

    2011-01-01

    The NO emissions of a semi-anthracite and a high-volatile bituminous coal were studied under oxy-fuel combustion conditions in an entrained flow reactor (EFR). The results obtained under oxy-fuel atmospheres (21%O2–79%CO2, 30%O2–70%CO2 and 35%O2–65%CO2), were compared with those produced in air. The replacement of CO2 by 5, 10, and 20% of steam in the oxy-fuel combustion atmospheres was also evaluated in order to study the wet recirculation of flue gas. The NO emissions during oxy-fuel combus...

  8. Oxy-combustion of high water content fuels

    Yi, Fei

    As the issues of global warming and the energy crisis arouse extensive concern, more and more research is focused on maximizing energy efficiency and capturing CO2 in power generation. To achieve this, in this research, we propose an unconventional concept of combustion - direct combustion of high water content fuels. Due to the high water content in the fuels, they may not burn under air-fired conditions. Therefore, oxy-combustion is applied. Three applications of this concept in power generation are proposed - direct steam generation for the turbine cycle, staged oxy-combustion with zero flue gas recycle, and oxy-combustion in a low speed diesel-type engine. The proposed processes could provide alternative approaches to directly utilize fuels which intrinsically have high water content. A large amount of energy to remove the water, when the fuels are utilized in a conventional approach, is saved. The properties and difficulty in dewatering high water content fuels (e.g. bioethanol, microalgae and fine coal) are summarized. These fuels include both renewable and fossil fuels. In addition, the technique can also allow for low-cost carbon capture due to oxy-combustion. When renewable fuel is utilized, the whole process can be carbon negative. To validate and evaluate this concept, the research focused on the investigation of the flame stability and characteristics for high water content fuels. My study has demonstrated the feasibility of burning fuels that have been heavily diluted with water in a swirl-stabilized burner. Ethanol and 1-propanol were first tested as the fuels and the flame stability maps were obtained. Flame stability, as characterized by the blow-off limit -- the lowest O2 concentration when a flame could exist under a given oxidizer flow rate, was determined as a function of total oxidizer flow rate, fuel concentration and nozzle type. Furthermore, both the gas temperature contour and the overall ethanol concentration in the droplets along the

  9. Numerical investigation of heat transfer characteristics in utility boilers of oxy-coal combustion

    Highlights: • Air-coal and oxy-coal combustion in an industrial scale PF boiler were simulated in ANSYS FLUENT. • The O2 concentration of 33 vol% in the oxy-coal combustion case matches the air-coal combustion case most closely. • The moisture in the flue gas has little impact on flame temperature, but positive impact on surface incident radiation. - Abstract: Oxy-coal combustion has different flue gas composition from the conventional air-coal combustion. The different composition further results in different properties, such as the absorption coefficient, emissivity, and density, which can directly affect the heat transfer in both radiation and convection zones of utility boilers. This paper numerically studied a utility boiler of oxy-coal combustion and compares with air-coal combustion in terms of flame profile and heat transferred through boiler side walls in order to understand the effects of different operating conditions on oxy-coal boiler retrofitting and design. Based on the results, it was found that around 33 vol% of effective O2 concentration ([O2]effective) the highest flame temperature and total heat transferred through boiler side walls in the oxy-coal combustion case match to those in the air-coal combustion case most; therefore, the 33 vol% of [O2]effective could result in the minimal change for the oxy-coal combustion retrofitting of the existing boiler. In addition, the increase of the moisture content in the flue gas has little impact on the flame temperature, but results in a higher surface incident radiation on boiler side walls. The area of heat exchangers in the boiler was also investigated regarding retrofitting. If boiler operates under a higher [O2]effective, to rebalance the load of each heat exchanger in the boiler, the feed water temperature after economizer can be reduced or part of superheating surfaces can be moved into the radiation zone to replace part of the evaporators

  10. Preclinical Activity of the Vascular Disrupting Agent OXi4503 against Head and Neck Cancer

    Katelyn D. Bothwell

    2016-01-01

    Full Text Available Vascular disrupting agents (VDAs represent a relatively distinct class of agents that target established blood vessels in tumors. In this study, we examined the preclinical activity of the second-generation VDA OXi4503 against human head and neck squamous cell carcinoma (HNSCC. Studies were performed in subcutaneous and orthotopic FaDu-luc HNSCC xenografts established in immunodeficient mice. In the subcutaneous model, bioluminescence imaging (BLI along with tumor growth measurements was performed to assess tumor response to therapy. In mice bearing orthotopic tumors, a dual modality imaging approach based on BLI and magnetic resonance imaging (MRI was utilized. Correlative histologic assessment of tumors was performed to validate imaging data. Dynamic BLI revealed a marked reduction in radiance within a few hours of OXi4503 administration compared to baseline levels. However, this reduction was transient with vascular recovery observed at 24 h post treatment. A single injection of OXi4503 (40 mg/kg resulted in a significant (p < 0.01 tumor growth inhibition of subcutaneous FaDu-luc xenografts. MRI revealed a significant reduction (p < 0.05 in volume of orthotopic tumors at 10 days post two doses of OXi4503 treatment. Corresponding histologic (H&E sections of Oxi4503 treated tumors showed extensive areas of necrosis and hemorrhaging compared to untreated controls. To the best of our knowledge, this is the first report, on the activity of Oxi4503 against HNSCC. These results demonstrate the potential of tumor-VDAs in head and neck cancer. Further examination of the antivascular and antitumor activity of Oxi4503 against HNSCC alone and in combination with chemotherapy and radiation is warranted.

  11. Tantalum (oxy)nitrides nanotube arrays for the degradation of atrazine in vis-Fenton-like process

    Highlights: ► Tantala nanotubes on a Ta foil were formed by anodization in a NH4F-containing electrolyte. ► Tantalum (oxy)nitrides nanotubes were active for Fe3+ reduction under visible light. ► Atrazine degradation by ·OH was accelerated with tantalum (oxy)nitrides nanotubes. ► Tantalum (oxy)nitrides nanotubes display stable performance for atrazine degradation. - Abstract: In order to overcome the limitation of the application of nanoparticles, tantalum (oxy)nitrides nanotube arrays on a Ta foil were synthesized and introduced in vis (visible light)-Fenton-like system to enhance the degradation of atrazine. At first, the anodization of tantalum foil in a mild electrolyte solution containing ethylene glycol and water (v:v = 2:1) plus 0.5 wt.% NH4F produced tantala nanotubes with an average diameter of 30 nm and a length of approximately 1 μm. Then the nitridation of tantala nanotube arrays resulted in the replacement of N atoms to O atoms to form tantalum (oxy)nitrides (TaON and Ta3N5), as testified by XRD and XPS analyses. The synthesized tantalum (oxy)nitrides nanotubes absorb well in the visible region up to 600 nm. Under visible light, tantalum (oxy)nitrides nanotube arrays were catalytically active for Fe3+ reduction. With tantalum (oxy)nitrides nanotube arrays, the degradation of atrazine and the formation of the intermediates in vis/Fe3+/H2O2 system were significantly accelerated. This was explained by the higher concentration of Fe2+ and thus the faster decomposition of H2O2 with tantalum (oxy)nitrides nanotubes. In addition, tantalum (oxy)nitrides nanotubes exhibited stable performance during atrazine degradation for three runs. The good performance and stability of the tantalum (oxy)nitrides nanotubes film with the convenient separation, suggest that this film is a promising catalyst for vis-Fenton-like degradation.

  12. Comparison of char structural characteristics and reactivity during conventional air and oxy-fuel combustion

    Liu, Xiaowei; Xu, Minghou; Yao, Hong; Gu, Ying; Si, Junping; Xiong, Chao [Huazhong Univ. of Science and Technology, Wuhan (China). State Key Lab. of Coal Combustion

    2013-07-01

    The capture and sequestration of CO{sub 2} generated from large- scale stationary power plants is considered to be one of the leading technologies that could potentially have a significant impact on reducing greenhouse emissions. Among these emerging technologies, the oxy-fuel combustion is a near-zero emission technology that can be adapted to both new and existing pulverized coal-fired power stations. The goal of this work is to make a comparative study on char structural characteristics (including char yield, swelling ratio, BET surface area, pore distribution, morphology) and reactivity during conventional air and oxy-fuel combustion. Specific experimental designs include two series. One is carried out in pure N{sub 2} and CO{sub 2} (pyrolysis experiments), and another is prepared in N{sub 2} + 5%O{sub 2} and CO{sub 2} + 5%O{sub 2}. Coal samples included raw coal, low density fraction coal and medium density fraction coal in all experiments. The present study is a further effort to extend our knowledge about physical and chemical structural characteristics and reactivity of char in the presence of high concentration CO{sub 2}. Combustion and pyrolysis of a density fractionated China coal at drop tube furnace yielded the following conclusions. Compared to oxy-chars obtained under pure CO{sub 2} atmosphere, the swelling ratios of char obtained in pure N{sub 2} atmosphere are higher. When adding 5%O{sub 2}, experimental results are completely different with those of the pyrolysis experiment. In comparison with the oxy-chars obtained under CO{sub 2} + 5%O{sub 2} atmosphere, the swelling ratios of the char obtained in N{sub 2} + 5%O{sub 2} atmosphere are lower. In the pyrolysis experiment, the BET surfaces Area of the oxy-chars are about 10-20 times as much as chars. When adding 5%O{sub 2}, the BET surfaces Area of the oxy-chars are about two to four times as much as chars. During pyrolysis experiment, the total pore volumes of the oxy-chars obtained under pure CO

  13. Biphasic oxidation of oxy-hemoglobin in bloodstains.

    Rolf H Bremmer

    Full Text Available BACKGROUND: In forensic science, age determination of bloodstains can be crucial in reconstructing crimes. Upon exiting the body, bloodstains transit from bright red to dark brown, which is attributed to oxidation of oxy-hemoglobin (HbO(2 to met-hemoglobin (met-Hb and hemichrome (HC. The fractions of HbO(2, met-Hb and HC in a bloodstain can be used for age determination of bloodstains. In this study, we further analyze the conversion of HbO(2 to met-Hb and HC, and determine the effect of temperature and humidity on the conversion rates. METHODOLOGY: The fractions of HbO(2, met-Hb and HC in a bloodstain, as determined by quantitative analysis of optical reflectance spectra (450-800 nm, were measured as function of age, temperature and humidity. Additionally, Optical Coherence Tomography around 1300 nm was used to confirm quantitative spectral analysis approach. CONCLUSIONS: The oxidation rate of HbO(2 in bloodstains is biphasic. At first, the oxidation of HbO(2 is rapid, but slows down after a few hours. These oxidation rates are strongly temperature dependent. However, the oxidation of HbO(2 seems to be independent of humidity, whereas the transition of met-Hb into HC strongly depends on humidity. Knowledge of these decay rates is indispensable for translating laboratory results into forensic practice, and to enable bloodstain age determination on the crime scene.

  14. Resilience and ductility of Oxy-fuel HAZ cut

    A. Martín-Meizoso,

    2014-10-01

    Full Text Available Cutting processes affect the material to a deeper or shallower attached-to-the-cut zone. Its microstructure, its hardness and mechanical properties are changed. Also the cutting process introduces surface roughness and residual stresses. In most cases it is recommended to remove this region by grinding, in order to keep a smoother surface, free from the above mentioned effects. This work presents the characterization results of the Heat Affected Zone (HAZ of a steel plate of grade S460M, with a thickness of 25 mm, cut by flame oxyfuel gas cutting. The HAZ microstructure is observed (and the depth of the HAZ measured, the hardness profile and the stress vs. strain curves until fracture are measured by testing micro-tensile samples, instrumented with strain gauges. Micro-Tensile specimens are 200 microns in thickness and were obtained from layers of the HAZ at different distances from the oxy-fuel cut. The obtained stress-strain curves are compared with the hardness measurements and the observed metallography.

  15. An advanced oxy-fuel power cycle with high efficiency

    Gou, C.; Hong, H. [University of Science and Technology, Beijing (China). Mechanical School; Cai, R. [Chinese Academy of Sciences, Beijing (China). Institute of Engineering Thermophysics

    2006-07-01

    In this article, an innovative oxy-fuel power cycle is proposed as a promising CO{sub 2} emission mitigation solution. It includes two cases with different characteristics in the cycle configuration. Case 1 basically consists of a water steam Rankine cycle and a steam-CO{sub 2} recuperative-reheat cycle. Case 2 integrates some characteristics of Case 1 and a top Brayton cycle. The thermodynamic performances for the design conditions of these two cases were analysed using the advanced process simulator Aspen Plus and the results are given in detail. The corresponding exergy loss analyses were carried out to gain an understanding of the loss distribution. The MATIANT cycle, the CES cycle, and the GRAZ cycle were also evaluated as references. The results demonstrate that the proposed cycle has notable advantages in thermal efficiency, specific work, and technical feasibility compared with the reference cycles. For example, the thermal efficiency of Case 2 is 6.58 percentage points higher than that of the MATIANT cycle. (author)

  16. Dynamic-Stability Characteristics of Premixed Methane Oxy-Combustion

    Shroll, Andrew P.

    2012-01-01

    This work explores the dynamic stability characteristics of premixed CH 4/O 2/CO 2 mixtures in a 50 kW swirl stabilized combustor. In all cases, the methane-oxygen mixture is stoichiometric, with different dilution levels of carbon dioxide used to control the flame temperature (T ad). For the highest T ad\\'s, the combustor is unstable at the first harmonic of the combustor\\'s natural frequency. As the temperature is reduced, the combustor jumps to fundamental mode and then to a low-frequency mode whose value is well below the combustor\\'s natural frequency, before eventually reaching blowoff. Similar to the case of CH 4/air mixtures, the transition from one mode to another is predominantly a function of the T ad of the reactive mixture, despite significant differences in laminar burning velocity and/or strained flame consumption speed between air and oxy-fuel mixtures for a given T ad. High speed images support this finding by revealing similar vortex breakdown modes and thus similar turbulent flame geometries that change as a function of flame temperature. Copyright © 2012 American Society of Mechanical Engineers.

  17. Energy analysis and environmental impacts of a MSW oxy-fuel incineration power plant in China

    The entire life cycle of a municipal solid waste (MSW) oxy-fuel incineration power plant was evaluated using the method of life cycle assessment (LCA) to identify and quantify the fossil energy requirements and environmental impacts. The functional unit was 1000 kg (1 t) MSW. During the life cycle, the saving standard coal by electricity generation was more than diesel consumption, and the effect of soot and ashes was the greatest among all calculated categorization impacts. The total weighted resource consumption and total weighted environment potential of MSW oxy-fuel incineration were −0.37 mPR90 (milli person equivalent) and −0.27 PET2010 (person equivalent), better than MSW incineration with CO2 capture via monoethanolamine (MEA) absorption. The sensitivity analysis showed that the electric power consumption of air separation unit (ASU) was the primary influencing parameter, and the influence of electric power consumption of CO2 compressor was secondary, while transport distance had small influence. Overall, MSW oxy-fuel incineration technology has certain development potential with the increment of MSW power supply efficiency and development of ASU in the future. - Highlights: • Life cycle assessment of a MSW oxy-fuel incineration power plant is novel. • The MSW oxy-fuel incineration was better than the MSW incineration with MEA. • Among calculated impacts, the effect of soot and ashes was the greatest. • The electric power consumption of ASU was the primary influencing parameter

  18. Oxy-Combustion Burner and Integrated Pollutant Removal Research and Development Test Facility

    Mark Schoenfield; Manny Menendez; Thomas Ochs; Rigel Woodside; Danylo Oryshchyn

    2012-09-30

    A high flame temperature oxy-combustion test facility consisting of a 5 MWe equivalent test boiler facility and 20 KWe equivalent IPR® was constructed at the Hammond, Indiana manufacturing site. The test facility was operated natural gas and coal fuels and parametric studies were performed to determine the optimal performance conditions and generated the necessary technical data required to demonstrate the technologies are viable for technical and economic scale-up. Flame temperatures between 4930-6120F were achieved with high flame temperature oxy-natural gas combustion depending on whether additional recirculated flue gases are added to balance the heat transfer. For high flame temperature oxy-coal combustion, flame temperatures in excess of 4500F were achieved and demonstrated to be consistent with computational fluid dynamic modeling of the burner system. The project demonstrated feasibility and effectiveness of the Jupiter Oxygen high flame temperature oxy-combustion process with Integrated Pollutant Removal process for CCS and CCUS. With these technologies total parasitic power requirements for both oxygen production and carbon capture currently are in the range of 20% of the gross power output. The Jupiter Oxygen high flame temperature oxy-combustion process has been demonstrated at a Technology Readiness Level of 6 and is ready for commencement of a demonstration project.

  19. Large scale study on measurement of respiration activity (AT(4)) by Sapromat and OxiTop.

    Binner, Erwin; Böhm, Katharina; Lechner, Peter

    2012-10-01

    In the run-up for amending the Austrian landfill ordinance, parameters were developed to assess the stability/reactivity of mechanically-biologically pretreated residual wastes. The Landfill Ordinance 2008 regulates limit values for Respiration Activity (="Atmungsaktivität") RA(4) (AT(4))wastes (sewage sludge, commercial waste, material from abandoned sites, biowaste compost). For measurement of respiration activity in Austria mainly two methods are used: the Sapromat®-method and the OxiTop®-method. Whether respectively to what extent these two methods give same results, is discussed in this paper. Since 2009 at ABF-BOKU 169 respiration activity tests of samples taken from different stages of MBT - as well as biowaste composting processes, materials from landfills as well as abandoned sites and residues from anaerobic treatment plants were analysed parallel by Sapromat® and OxiTop®. The results manifest very strong correlation between the Sapromat® and OxiTop® method. The correlation coefficient is 0.993. As a very clear tendency OxiTop® gives lower amounts than Sapromat®. In average the lower values of OxiTop® are around 88%. PMID:22704002

  20. Evaluation of gas radiation models in CFD modeling of oxy-combustion

    Highlights: • CFD modeling of a typical industrial water tube boiler is conducted. • Different combustion processes were considered including air and oxy-fuel combustion. • SGG, EWBM, Leckner, Perry and WSGG radiation models were considered in the study. • EWBM is the most accurate model and it’s considered to be the benchmark model. • Characteristics of oxy-fuel combustion are compared to those of air–fuel combustion. - Abstract: Proper determination of the radiation energy is very important for proper predictions of the combustion characteristics inside combustion devices using CFD modeling. For this purpose, different gas radiation models were developed and applied in the present work. These radiation models vary in their accuracy and complexity according to the application. In this work, a CFD model for a typical industrial water tube boiler was developed, considering three different combustion environments. The combustion environments are air–fuel combustion (21% O2 and 79% N2), oxy-fuel combustion (21% O2 and 79% CO2) and oxy-fuel combustion (27% O2 and 73% CO2). Simple grey gas (SGG), exponential wide band model (EWBM), Leckner, Perry and weighted sum of grey gases (WSGG) radiation models were examined and their influences on the combustion characteristics were evaluated. Among those radiation models, the EWBM was found to provide close results to the experimental data for the present boiler combustion application. The oxy-fuel combustion characteristics were analyzed and compared with those of air–fuel combustion

  1. A Reduced Order Model for the Design of Oxy-Coal Combustion Systems

    Steven L. Rowan

    2015-01-01

    Full Text Available Oxy-coal combustion is one of the more promising technologies currently under development for addressing the issues associated with greenhouse gas emissions from coal-fired power plants. Oxy-coal combustion involves combusting the coal fuel in mixtures of pure oxygen and recycled flue gas (RFG consisting of mainly carbon dioxide (CO2. As a consequence, many researchers and power plant designers have turned to CFD simulations for the study and design of new oxy-coal combustion power plants, as well as refitting existing air-coal combustion facilities to oxy-coal combustion operations. While CFD is a powerful tool that can provide a vast amount of information, the simulations themselves can be quite expensive in terms of computational resources and time investment. As a remedy, a reduced order model (ROM for oxy-coal combustion has been developed to supplement the CFD simulations. With this model, it is possible to quickly estimate the average outlet temperature of combustion flue gases given a known set of mass flow rates of fuel and oxidant entering the power plant boiler as well as determine the required reactor inlet mass flow rates for a desired outlet temperature. Several cases have been examined with this model. The results compare quite favorably to full CFD simulation results.

  2. Second law comparison of oxy-fuel combustion and post-combustion carbon dioxide separation

    To define 2nd law efficiency targets for novel separation technologies, a simplified model of a power plant with two forms of CO2 capture was developed. In this investigation, oxy-fuel combustion and post-combustion CO2 separation were compared on an exergetic basis. Using exergy balances and black-box models of power plant components, multiple scenarios were run to determine the impact of plant configuration and separation unit efficiency on overall plant performance. Second law efficiency values from the literature were used to set the baseline performance of various CO2 separation configurations. Assumed advances in 2nd law efficiency were used to determine the potential for overall system performance improvement. It was found that the 2nd law efficiency of air separation must reach a critical value before the thermodynamics of oxy-fuel combustion become favorable. Changes in operating equivalence ratio significantly move the tipping-point between post-combustion and oxy-fuel strategies

  3. Performance of a Wet Flue Gas Desulfurization Pilot Plant under Oxy-Fuel Conditions

    Hansen, Brian Brun; Fogh, Folmer; Knudsen, Niels Ole;

    2011-01-01

    Oxy-fuel firing is a promising technology that should enable the capture and storage of anthropogenic CO2 emissions from large stationary sources such as power plants and heavy industry. However, this new technology has a high energy demand for air separation and CO2 compression and storage....... Unresolved issues, such as determination of the optimal recycle location of flue gas, the flue gas cleaning steps required (SO2, NOx, and particles), and the impact of an oxy-fuel flue gas on the cleaning steps, also persist. The aim of this work was to study the performance of the wet flue gas...... desulfurization (FGD) process under operating conditions corresponding to oxy-fuel firing. The most important output parameters were the overall degree of desulfurization and the residual limestone concentration in the gypsum slurry. Pilot-scale experiments quantified that the introduction of a flue gas with 90...

  4. Effects of (Oxy-)Fluorination on Various High-Performance Yarns.

    Kruppke, Iris; Bartusch, Matthias; Hickmann, Rico; Hund, Rolf-Dieter; Cherif, Chokri

    2016-01-01

    In this work, typical high-performance yarns are oxy-fluorinated, such as carbon fibers, ultra-high-molecular-weight polyethylene, poly(p-phenylene sulfide) and poly(p-phenylene terephthalamide). The focus is on the property changes of the fiber surface, especially the wetting behavior, structure and chemical composition. Therefore, contact angle, XPS and tensile strength measurements are performed on treated and untreated fibers, while SEM is utilized to evaluate the surface structure. Different results for the fiber materials are observed. While polyethylene exhibits a relevant impact on both surface and bulk properties, polyphenylene terephthalamide and polyphenylene sulfide are only affected slightly by (oxy-)fluorination. The wetting of carbon fiber needs higher treatment intensities, but in contrast to the organic fibers, even its textile-physical properties are enhanced by the treatment. Based on these findings, the capability of (oxy-)fluorination to improve the adhesion of textiles in fiber-reinforced composite materials can be derived. PMID:27571055

  5. Aluminum coatings deposition by oxy-fuel detonation spraying

    This paper presents the possibility of control by phase composition of gaseous detonation sprayed coatings from aluminum powders due to variation and control of intensity of oxidation and combustion of initial Al particle. Thermal sprayed aluminum coatings have good corrosion resistance, but for some area of application they don't have acceptable complex of properties. The actual problem is also increase of strength of aluminum matrix in composite manufacturing by thermal spraying. The cooling rate of Al particles at plasma spraying as result of experimental determination of dendrite sizes is 10/sup 6/ - 10/sup 8/ degree C/s. But strengthening as result of microcrystal structure formation is withdrawing by presence of large pores and cracks between solidified particles. Therefore, it is necessary to search of thermal spray methods for obtaining more dense structure of coatings. Oxy-fuel detonation spraying (OFDS) is allowed to deposit coatings simultaneously from large and small particles. Moreover, in case of OFDS it is possible to use reaction of AI-particles oxidation and to obtain oxide-metal coatings. During oxidation of Al particles the surface film of aluminum is formed. Aluminum -aluminum oxide alloys are the strongest and most stable aluminum alloys above about 127 to 158 degree C. Their stability results from the extremely low solid solubility of Al/sub 2/O/sub 3/ The heat of chemical reaction may render on processes of heating, melting and overheating of particles. The possibility of control by phase composition of oxy fuel detonation sprayed coatings from aluminum powders as result of control of intensity of oxidation and combustion of initial Al particles are shown. The special schemes of gaseous detonation spraying are proposed. The experiments were done for OFDS of three types of powders of pure AI: (1) fine aluminum powder; (2) Al powder with particle size 100 - 250 macro m; (3) Al powder particle size 40 macro m. The composition of gas mixture was

  6. Emission characteristics and combustion instabilities in an oxy-fuel swirl-stabilized combustor

    Guo-neng LI; Hao ZHOU; Ke-fa CEN

    2008-01-01

    This paper presents an experimental study on the emission characteristics and combustion instabilities of oxy-fuel combustions in a swirl-stabilized combustor.Different oxygen concentrations(Xoxy=25%-45%,where Xoxy is oxygen concentra-tion by volume),equivalence ratios(=0.75~1.15)and combustion powers(CP=1.08~2.02kW)were investigated in the oxy-fuel (CH4/CO2/O2)combustions,and reference cases(Xoxy=25%~35%,Cha/N2/O2 flames)were covered.The results show that the oxygen concentration in the oxidant stream significantly affects the combustion delay in the oxy-fuel flames,and the equivalence ratio has a slight effect,whereas the combustion power shows no impact.The temperature levels of the oxy-fuel flames inside the combustion chamber are much higher(up to 38.7%)than those of the reference cases.Carbon monoxide was vastly producedwhen Xoxy>35% or >0.95 in the oxy-fuel flames,while no nitric oxide was found in the exhaust gases because no N2 participates in the combustion process.The combustion instability of the oxy-fuel combustion is very different from those of the reference cases with similar oxygen content.Oxy-fuel combustions excite strong oscillations in all cases studied Xoxy=25%~45%.However,no pressure fluctuations were detected in the reference cases when Xoxy>28.6% accomplished by heavily sooting flames which were not found in the oxy-fuel combustions.Spectrum analysis shows that the frequency of dynamic pressure oscillations exhibits randomness in the range of 50~250 Hz,therefore resulting in a very small resultant amplitude.Temporal oscillations are very strong with amplitudes larger than 200 Pa,even short time fast Fourier transform(FFT)analysis(0.08 s)shows that the pressure amplitude can be larger than 40 Pa.

  7. The Effect of Oxygen Staging on Nitrogen Conversion in Oxy-Fuel CFB Environment

    Jankowska Sylwia; Czakiert Tomasz; Krawczyk Grzegorz; Borecki Paweł; Jesionowski Łukasz; Nowak Wojciech

    2014-01-01

    This paper presents a study on nitrogen conversion in oxy-fuel coal combustion in a pilot scale CFB 0.1 MWth facility. The paper is focused on fuel-N behaviour in the combustion chamber when the combustion process is accomplished under oxy-fuel CFB conditions. The analysis is based on infurnace sampling of flue gas and calculations of the conversion ratios of fuel-nitrogen (fuel-N) to NO, NO2, N2O, NH3 and HCN. For the tests, O2/CO2 mixtures with the oxygen content of 21 vol.% (primary gas) a...

  8. Effect of Atmosphere on Volatile Emission Characteristic in Oxy-Fuel Combustion

    Jia Luo; Shihe Chen; Le Wu

    2013-01-01

    A new type of power supply which was called oxy-fuel combustion power plant was introduced to reduce greenhouse gasses emission. In this paper the volatile emission characteristic of pulverized coal is studied under air atmosphere and oxy-fuel atmosphere. Combustion experiments of Datong bituminous coal were carried out in a wire mesh reactor at heating rates of 1 K/s, 10 K/s and 1000 K/s respectively under air and O2/CO2 atmosphere conditions in order to investigate the volatile emission ch...

  9. Gas Temperature and Radiative Heat Transfer in Oxy-fuel Flames

    Bäckström, Daniel; Johansson, Robert; Andersson, Klas; Johnsson, Filip; Clausen, Sønnik; Fateev, Alexander

    2012-01-01

    This work presents measurements of the gas temperature, including fluctuations, and its influence on the radiative heat transfer in oxy-fuel flames. The measurements were carried out in the Chalmers 100 kW oxy-fuel test unit. The in-furnace gas temperature was measured by a suction pyrometer and by an optical system based on FTIR-spectroscopy. The radiation intensity was measured by a Narrow Angle Radiometer and the gas radiation was calculated with a Statistical Narrow Band model. The overal...

  10. Optimum temperature for sulphur retention in fluidised beds working under oxy-fuel combustion conditions

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

    2013-01-01

    Oxy-fuel combustion is one of the leading options for power generation with CO 2 capture. The process consists of burning the fuel with a mixture of nearly pure oxygen and a CO 2 -rich recycled flue gas, result- ing in a product flue gas from the boiler containing mainly CO 2 and H 2 O. Among the possible boiler types, fluidised bed combustors are very appropriate for the oxy-fuel process because they allow the in situ des- ulphurisation by feeding Ca-based...

  11. Comparisons between oxy-fuel combustion and IGCC technologies in China coal- energy industry

    Zhao, Xue; Clemente Jul, María del Carmen

    2010-01-01

    A comparison between oxy-fuel combustion plants and IGCC plants has been carried out. Oxy-fuel combustion performs better for the retrofit of exist pulverized coal plants after the evaluation of efficiency, retrofit cost and O&M cost. China is currently and will depending on coal for its energy for a long time. Plenty of PC plants are used in existing power plants due to its lower coal consumption. One way to reduce CO2 emission with CCS is to equip existing power plants with appliance...

  12. A study of oxy-coal combustion with steam addition and biomass blending by thermogravimetric analysis

    Gil Matellanes, María Victoria; Riaza Benito, Juan; Álvarez González, Lucía; Pevida García, Covadonga; Pis Martínez, José Juan; Rubiera González, Fernando

    2011-01-01

    The thermal characteristics of pulverized coal have been studied under oxy-fuel combustion conditions using non-isothermal thermogravimetric analysis (TG). The atmospheres used were 21%O2/79%N2, 21%O2/79%CO2, 30%O2/70%O2, and 35%O2/65%CO2. Coal blends of coal with 10 and 20% of biomass were also studied under these atmospheres. The addition of 10 and 20% of steam was evaluated for the oxy-fuel combustion atmospheres with 21 and 30% of O2 in order to study the effect of the wet recirculation o...

  13. Corrosion in refractories for glass furnaces with 100% oxy-firing combustion: part 2 - mullite

    Looking forward to getting better yielding in glass furnaces Santa Marina and White Martins used 100% oxy-firing process. This new technique decrease the pollutants gases and emission of particles to concentration lower than that allowed limit without using auxiliary equipment against pollution. However, the atmosphere generated by the oxy-oil combustion can become more aggressive to some refractories decreasing its mean life. Aiming to determine the performance of mullite based refractories, the new phases formed due to corrosive action of alkalis were analysed. The refractories were analysed by DRX, MEV, mercury porosimetry and X ray fluorescence. (author) DRX, MEV, mercury porosimetry and X ray fluorescence. (author)

  14. Therapeutic potential of using the vascular disrupting agent OXi4503 to enhance mild temperature thermoradiation

    Horsman, Michael R

    2015-01-01

    female CDF1 mice or foot-implanted C3H mammary carcinomas were locally irradiated (230 kV X-rays) and heated (41.5 °C for 60 min) by foot immersion in a water bath. OXi4503 (50 mg/kg) was injected intraperitoneally 1.5 h before irradiating. Irradiation was performed either in the middle of the heating...... seen with the sequential treatment. CONCLUSION: Combining OXi4503 with a sequential radiation and heat treatment resulted in a 1.4-fold therapeutic gain....

  15. Escherichia coli OxyR modulation of bacteriophage Mu mom expression in dam+ cells can be attributed to its ability to bind hemimethylated Pmom promoter DNA.

    Hattman, S; Sun, W.

    1997-01-01

    Transcription of the bacteriophage Mu mom operon is strongly repressed by the host OxyR protein in dam - but not dam + cells. In this work we show that the extent of mom modification is sensitive to the relative levels of the Dam and OxyR proteins and OxyR appears to modulate the level of mom expression even in dam + cells. In vitro studies demonstrated that OxyR is capable of binding hemimethylated P mom , although its affinity is reduced slightly compared with unmethylated DNA. Thus, OxyR m...

  16. Changes in antioxidative protection in bean cotyledons during natural and continuous irradiation-accelerated senescence

    Procházková, Dagmar; Wilhelmová, Naděžda

    2004-01-01

    Roč. 48, č. 1 (2004), s. 33-39. ISSN 0006-3134 R&D Projects: GA ČR GA522/03/0312 Institutional research plan: CEZ:AV0Z5038910 Keywords : Antioxidants * reactive oxygen species * senescence Subject RIV: EF - Botanics Impact factor: 0.744, year: 2004

  17. Aging is associated with decreased maximal life span and accelerated senescence of bone marrow stromal cells

    Dokkedahl, Karin Stenderup; Justesen, Jeannette; Clausen, Christian;

    2003-01-01

    Age-related decrease in bone formation is well described. However, the cellular causes are not known. Thus, we have established cultures of bone marrow stromal cells (MSC) from young (aged 18-29 years, n = 6) and old (aged 68-81 years, n = 5) donors. MSC were serially passaged until reaching maxi...

  18. MSW oxy-enriched incineration technology applied in China: combustion temperature, flue gas loss and economic considerations.

    Fu, Zhe; Zhang, Shihong; Li, Xiangpeng; Shao, Jingai; Wang, Ke; Chen, Hanping

    2015-04-01

    To investigate the application prospect of MSW oxy-enriched incineration technology in China, the technical and economical analyses of a municipal solid waste (MSW) grate furnace with oxy-fuel incineration technology in comparison to co-incineration with coal are performed. The rated capacity of the grate furnace is 350 tonnes MSW per day. When raw MSW is burned, the amount of pure oxygen injected should be about 14.5 wt.% under 25% O2 oxy-fuel combustion conditions with the mode of oxygen supply determined by the actual situation. According to the isothermal combustion temperature (Ta), the combustion effect of 25% O2 oxy-enriched incineration (α = 1.43) is identical with that of MSW co-incineration with 20% mass ratio of coal (α = 1.91). However, the former is better than the latter in terms of plant cost, flue gas loss, and environmental impact. Despite the lower costs of MSW co-incineration with mass ratio of 5% and 10% coal (α = 1.91), 25% O2 oxy-enriched incineration (α = 1.43) is far more advantageous in combustion and pollutant control. Conventional combustion flue gas loss (q2) for co-incineration with 0% coal, 20% coal, 10% coal, 5% coal are around 17%, 13%, 14% and 15%, respectively, while that under the condition of 25% O2 oxy-enriched combustion is approximately 12% (α = 1.43). Clearly, q2 of oxy-enriched incineration is less than other methods under the same combustion conditions. High moisture content presents challenges for MSW incineration, therefore it is necessary to dry MSW prior to incineration, and making oxy-enriched incineration technology achieves higher combustion temperature and lower flue gas loss. In conclusion, based on technical and economical analysis, MSW oxy-enriched incineration retains obvious advantages and demonstrates great future prospects for MSW incineration in China. PMID:25680237

  19. Prediction of oxy-coal combustion through an optimized weighted sum of gray gases model

    Oxy-fuel combustion is considered as one of promising options for carbon dioxide capture in future coal power plants. Currently models available in CFD codes fail to predict accurately the radiative heat transfer in oxy-fuel cases due to higher pressure of carbon dioxide and water vapor. This paper concerns numerical investigation applying three band formulations aiming an accurate prediction of radiative properties. The radiative heat transfer is calculated by discrete ordinate method coupled with a weighted sum of gray gases model. The first case relates to the domain-based approach using air-fired parameters. In the last two cases, the optimized parameters of 3 and 4 gray gases fitted to oxy-fired conditions are implemented through a non-gray gases approach. Results applying these set of parameters are evaluated through a comparison with experimental data. Discrepancies between the predicted and measured velocity and O2 concentration are found mainly close to the burner due to shortcomings of the turbulence model and inaccurate thermochemical closure. The gas flame temperatures are better predicted by the optimized parameters for oxy-fuel conditions, which are considerably lower than the values calculated by the air-fired parameters. Similar trends are observed when the radiative heat fluxes at the lateral wall are compared.

  20. OH Diffusion in Silica Glass Preform During Jacketing Process by Oxy-Hydrogen Burner

    B.H.Kim; S.R.Han; U.; C.Paek; W.-T.Han; S.; K.Oh

    2003-01-01

    Radial distribution of OH diffusion in silica glass preform during jacketing process using a oxy-hydrogen burner was investigated by FTIR spectroscopy. The OH peaks at the jacketing boundary and the surface of the preform were found to be due to diffusion of OH incorporated from the burner.

  1. Ranking of enabling technologies for oxy-fuel based carbon capture

    Ochs, T.L.; Oryshchyn, D.L.; Ciferno, J.P.

    2007-06-01

    The USDOE National Energy Technology Laboratory (NETL) has begun a process to identify and rank enabling technologies that have significant impacts on pulverized coal oxy-fuel systems. Oxy-fuel combustion has been identified as a potential method for effectively capturing carbon in coal fired power plants. Presently there are a number of approaches for carbon capture via oxy-fuel combustion and it is important to order those approaches so that new research can concentrate on those technologies with high potentials to substantially lower the cost of reduced carbon electricity generation. NETL evaluates these technologies using computer models to determine the energy use of each technology and the potential impact of improvements in the technologies on energy production by a power plant. Near-term sub-critical boiler technologies are targeted for this analysis because: • most of the world continues to build single reheat sub-critical plants; • the overwhelming number of coal fired power plants requiring retrofit for CO2 capture are sub-critical plants. In addition, even in the realm of new construction, subcritical plants are common because they are well understood, easy to operate and maintain, fuel tolerant, and reliable. Following the initial investigation into sub-critical oxy-fuel technology, future investigations will move into the supercritical range.

  2. Crystal structure of 4-oxo-4H-chromene-3-carb-oxy-lic acid.

    Ishikawa, Yoshinobu

    2015-08-01

    In the title compound, C10H6O4, also known as 3-carb-oxy-chromone, the non-H atoms of the chromone ring are essentially coplanar (r.m.s. deviation = 0.0057 Å), with the maximum deviation from their least-squares plane [0.011 (2) Å] being for a pyran C atom. The dihedral angle between the fused ring and plane of the carb-oxy group is 3.06 (2)°. An intra-molecular hydrogen bond is formed between the ring carbonyl O atom and the carb-oxy O-H atom, closing an S(6) loop. In the crystal, mol-ecules are assembled by stacking inter-actions [centroid-centroid distance between the benzene and pyran rings = 3.844 (3) Å] and C-H⋯O hydrogen bonds, generating a three-dimensional network. Short contacts are also observed between the carb-oxy O and C atoms [C=O⋯C=O = 3.002 (3) Å]. PMID:26396807

  3. Synthesis of aluminum oxy-hydroxide nanofibers from porous anodic alumina.

    Jha, Himendra; Kikuchi, Tatsuya; Sakairi, Masatoshi; Takahashi, Hideaki

    2008-10-01

    A novel method for the synthesis of aluminum oxy-hydroxide nanofibers from a porous anodic oxide film of aluminum is demonstrated. In the present method, the porous anodic alumina not only acts as a template, but also serves as the starting material for the synthesis. The porous anodic alumina film is hydrothermally treated for pore-sealing, which forms aluminum oxy-hydroxide inside the pores of the oxide film as well as on the surface of the film. The hydrothermally sealed porous oxide film is immersed in the sodium citrate solution, which selectively etches the porous aluminum oxide from the film, leaving the oxy-hydroxide intact. The method is simple and gives highly uniform aluminum oxy-hydroxide nanofibers. Moreover, the diameter of the nanofibers can be controlled by controlling the pore size of the porous anodic alumina film, which depends on the anodizing conditions. Nanofibers with diameters of about 38-85 nm, having uniform shape and size, were successfully synthesized using the present method. PMID:21832599

  4. Synthesis of aluminum oxy-hydroxide nanofibers from porous anodic alumina

    Jha, Himendra; Kikuchi, Tatsuya; Sakairi, Masatoshi; Takahashi, Hideaki [Laboratory of Interface Microstructure Analysis (LIMSA), Division of Materials Science and Engineering, Graduate School of Engineering, Hokkaido University, Sapporo 060-8628 (Japan)], E-mail: himendra@eng.hokudai.ac.jp

    2008-10-01

    A novel method for the synthesis of aluminum oxy-hydroxide nanofibers from a porous anodic oxide film of aluminum is demonstrated. In the present method, the porous anodic alumina not only acts as a template, but also serves as the starting material for the synthesis. The porous anodic alumina film is hydrothermally treated for pore-sealing, which forms aluminum oxy-hydroxide inside the pores of the oxide film as well as on the surface of the film. The hydrothermally sealed porous oxide film is immersed in the sodium citrate solution, which selectively etches the porous aluminum oxide from the film, leaving the oxy-hydroxide intact. The method is simple and gives highly uniform aluminum oxy-hydroxide nanofibers. Moreover, the diameter of the nanofibers can be controlled by controlling the pore size of the porous anodic alumina film, which depends on the anodizing conditions. Nanofibers with diameters of about 38-85 nm, having uniform shape and size, were successfully synthesized using the present method.

  5. Demystifying "oxi" cocaine: Chemical profiling analysis of a "new Brazilian drug" from Acre State.

    da Silva Junior, Ronaldo C; Gomes, Cezar S; Goulart Júnior, Saulo S; Almeida, Fernanda V; Grobério, Tatiane S; Braga, Jez W B; Zacca, Jorge J; Vieira, Maurício L; Botelho, Elvio D; Maldaner, Adriano O

    2012-09-10

    Recent information from various sources suggests that a new illicit drug, called "oxi", is being spread across Brazil. It would be used in the smoked form and it would look like to crack cocaine: usually small yellowish or light brown stones. As fully released in the media, "oxi" would differ from crack cocaine in the sense that crack would contain carbonate or bicarbonate salts whereas "oxi" would include the addition of calcium oxide and kerosene (or gasoline). In this context, this work presents a chemical profiling comparative study between "oxi" street samples seized by the Civil Police of the State of Acre (CP/AC) and samples associated with both international and interstate drug trafficking seized by the Brazilian Federal Police in Acre (FP/AC). The outcome of this work assisted Brazilian authorities to stop inaccurate and alarmist releases on this issue. It may be of good use by the forensic community in order to better understand matters in their efforts to guide local law enforcement agencies in case such claims reach the international illicit market. PMID:22571827

  6. Oxy-Fuel Cutting/Welding. Welding Module 3. Instructor's Guide.

    Missouri Univ., Columbia. Instructional Materials Lab.

    This guide is intended to assist vocational educators in teaching a four-unit module in oxy-fuel cutting and welding. The module is part of a welding curriculum that has been designed to be totally integrated with Missouri's Vocational Instruction Management System. The following topics are covered in the module: oxyacetylene welding, oxyacetylene…

  7. Development of Cost Effective Oxy-Combustion Retrofitting for Coal-Fired Boilers

    Hamid Farzan

    2010-12-31

    The overall objective of this project is to further develop the oxy-combustion technology for commercial retrofit in existing wall-fired and Cyclone boilers by 2012. To meet this goal, a research project was conducted that included pilot-scale testing and a full-scale engineering and economic analysis.

  8. Oxy-fuel combustion of pulverized fuels: Combustion fundamentals and modeling

    Yin, Chungen; Yan, Jinyue

    2016-01-01

    Oxy-fuel combustion of pulverized fuels (PF), as a promising technology for CO2 capture from power plants, has gained a lot of concerns and also advanced considerable research, development and demonstration in the last past years worldwide. The use of CO2 or the mixture of CO2 and H2O vapor as th...

  9. The OXI1 kinase pathway mediates Piriformospora indica-induced growth promotion in Arabidopsis.

    Iris Camehl

    2011-05-01

    Full Text Available Piriformospora indica is an endophytic fungus that colonizes roots of many plant species and promotes growth and resistance to certain plant pathogens. Despite its potential use in agriculture, little is known on the molecular basis of this beneficial plant-fungal interaction. In a genetic screen for plants, which do not show a P. indica- induced growth response, we isolated an Arabidopsis mutant in the OXI1 (Oxidative Signal Inducible1 gene. OXI1 has been characterized as a protein kinase which plays a role in pathogen response and is regulated by H₂O₂ and PDK1 (3-PHOSPHOINOSITIDE-DEPENDENT PROTEIN KINASE1. A genetic analysis showed that double mutants of the two closely related PDK1.1 and PDK1.2 genes are defective in the growth response to P. indica. While OXI1 and PDK1 gene expression is upregulated in P. indica-colonized roots, defense genes are downregulated, indicating that the fungus suppresses plant defense reactions. PDK1 is activated by phosphatidic acid (PA and P. indica triggers PA synthesis in Arabidopsis plants. Under beneficial co-cultivation conditions, H₂O₂ formation is even reduced by the fungus. Importantly, phospholipase D (PLDα1 or PLDδ mutants, which are impaired in PA synthesis do not show growth promotion in response to fungal infection. These data establish that the P. indica-stimulated growth response is mediated by a pathway consisting of the PLD-PDK1-OXI1 cascade.

  10. Membrane-integrated oxy-fuel combustion of coal: Process design and simulation

    Chen, Wei; Ham, van der A.G.J.; Nijmeijer, A.; Winnubst, A.J.A.

    2015-01-01

    A membrane-integrated oxy-fuel combustion process is designed and simulated in UniSim Design®. The results of the simulation indicate that a net efficiency of 31.8% is obtained for a coal-fired power plant of 182 MWth (assuming only carbon in the coal), including the compression of CO2 to 100 bar. T

  11. Recovery Act: Oxy-Combustion Techology Development for Industrial-Scale Boiler Applications

    Levasseur, Armand

    2014-04-30

    Alstom Power Inc. (Alstom), under U.S. DOE/NETL Cooperative Agreement No. DE-NT0005290, is conducting a development program to generate detailed technical information needed for application of oxy-combustion technology. The program is designed to provide the necessary information and understanding for the next step of large-scale commercial demonstration of oxy combustion in tangentially fired boilers and to accelerate the commercialization of this technology. The main project objectives include: • Design and develop an innovative oxyfuel system for existing tangentially-fired boiler units that minimizes overall capital investment and operating costs. • Evaluate performance of oxyfuel tangentially fired boiler systems in pilot scale tests at Alstom’s 15 MWth tangentially fired Boiler Simulation Facility (BSF). • Address technical gaps for the design of oxyfuel commercial utility boilers by focused testing and improvement of engineering and simulation tools. • Develop the design, performance and costs for a demonstration scale oxyfuel boiler and auxiliary systems. • Develop the design and costs for both industrial and utility commercial scale reference oxyfuel boilers and auxiliary systems that are optimized for overall plant performance and cost. • Define key design considerations and develop general guidelines for application of results to utility and different industrial applications. The project was initiated in October 2008 and the scope extended in 2010 under an ARRA award. The project completion date was April 30, 2014. Central to the project is 15 MWth testing in the BSF, which provided in-depth understanding of oxy-combustion under boiler conditions, detailed data for improvement of design tools, and key information for application to commercial scale oxy-fired boiler design. Eight comprehensive 15 MWth oxy-fired test campaigns were performed with different coals, providing detailed data on combustion, emissions, and thermal behavior over a

  12. Characterization of Oxy-combustion Impacts in Existing Coal-fired Boilers

    Adams, Bradley; Davis, Kevin; Senior, Constance; Shim, Hong Shim; Otten, Brydger; Fry, Andrew; Wendt, Jost; Eddings, Eric; Paschedag, Alan; Shaddix, Christopher; Cox, William; Tree, Dale

    2013-09-30

    Reaction Engineering International (REI) managed a team of experts from University of Utah, Siemens Energy, Praxair, Vattenfall AB, Sandia National Laboratories, Brigham Young University (BYU) and Corrosion Management Ltd. to perform multi-scale experiments, coupled with mechanism development, process modeling and CFD modeling, for both applied and fundamental investigations. The primary objective of this program was to acquire data and develop tools to characterize and predict impacts of CO{sub 2} flue gas recycle and burner feed design on flame characteristics (burnout, NO{sub x}, SO{sub x}, mercury and fine particle emissions, heat transfer) and operational concerns (fouling, slagging and corrosion) inherent in the retrofit of existing coal-fired boilers for oxy-coal combustion. Experimental work was conducted at Sandia National Laboratories’ Entrained Flow Reactor, the University of Utah Industrial Combustion Research Facility, and Brigham Young University. Process modeling and computational fluid dynamics (CFD) modeling was performed at REI. Successful completion of the project objectives resulted in the following key deliverables: 1) Multi-scale test data from 0.1 kW bench-scale, 100 kW and 200 kW laboratory-scale, and 1 MW semi-industrial scale combustors that describe differences in flame characteristics, fouling, slagging and corrosion for coal combustion under air-firing and oxygen-firing conditions, including sensitivity to oxy-burner design and flue gas recycle composition. 2) Validated mechanisms developed from test data that describe fouling, slagging, waterwall corrosion, heat transfer, char burnout and sooting under coal oxy-combustion conditions. The mechanisms were presented in a form suitable for inclusion in CFD models or process models. 3) Principles to guide design of pilot-scale and full-scale coal oxy-firing systems and flue gas recycle configurations, such that boiler operational impacts from oxy-combustion retrofits are minimized. 4

  13. New weighted sum of gray gases model applicable to Computational Fluid Dynamics (CFD) modeling of oxy-fuel combustion

    Yin, Chungen; Johansen, Lars Christian Riis; Rosendahl, Lasse; Kær, Søren Knudsen

    2010-01-01

    Radiation is the principal mode of heat transfer in furnaces. Models for gaseous radiative properties have been well established for air combustion. However, there is uncertainty regarding their applicability to oxy-fuel conditions. In this paper, a new and complete set of weighted sum of gray...... gases model (WSGGM) is derived, which is applicable to computational fluid dynamics (CFD) modeling of both air-fuel and oxy-fuel combustion. First, a computer code is developed to evaluate the emissivity of any gas mixture at any condition by using the exponential wide band model (EWBM), and the...... guidelines on oxy-fuel modeling are recommended....

  14. Novel Supercritical Carbon Dioxide Power Cycle Utilizing Pressured Oxy-combustion in Conjunction with Cryogenic Compression

    Brun, Klaus; McClung, Aaron; Davis, John

    2014-03-31

    The team of Southwest Research Institute® (SwRI) and Thar Energy LLC (Thar) applied technology engineering and economic analysis to evaluate two advanced oxy-combustion power cycles, the Cryogenic Pressurized Oxy-combustion Cycle (CPOC), and the Supercritical Oxy-combustion Cycle. This assessment evaluated the performance and economic cost of the two proposed cycles with carbon capture, and included a technology gap analysis of the proposed technologies to determine the technology readiness level of the cycle and the cycle components. The results of the engineering and economic analysis and the technology gap analysis were used to identify the next steps along the technology development roadmap for the selected cycle. The project objectives, as outlined in the FOA, were 90% CO{sub 2} removal at no more than a 35% increase in cost of electricity (COE) as compared to a Supercritical Pulverized Coal Plant without CO{sub 2} capture. The supercritical oxy-combustion power cycle with 99% carbon capture achieves a COE of $121/MWe. This revised COE represents a 21% reduction in cost as compared to supercritical steam with 90% carbon capture ($137/MWe). However, this represents a 49% increase in the COE over supercritical steam without carbon capture ($80.95/MWe), exceeding the 35% target. The supercritical oxy-combustion cycle with 99% carbon capture achieved a 37.9% HHV plant efficiency (39.3% LHV plant efficiency), when coupling a supercritical oxy-combustion thermal loop to an indirect supercritical CO{sub 2} (sCO{sub 2}) power block. In this configuration, the power block achieved 48% thermal efficiency for turbine inlet conditions of 650°C and 290 atm. Power block efficiencies near 60% are feasible with higher turbine inlet temperatures, however a design tradeoff to limit firing temperature to 650°C was made in order to use austenitic stainless steels for the high temperature pressure vessels and piping and to minimize the need for advanced turbomachinery features

  15. Predictions of the impurities in the CO2 stream of an oxy-coal combustion plant

    Whilst all three main carbon capture technologies (post-combustion, pre-combustion and oxy-fuel combustion) can produce a CO2 dominant stream, other impurities are expected to be present in the CO2 stream. The impurities in the CO2 stream can adversely affect other processes of the carbon capture and storage (CCS) chain including the purification, compression, transportation and storage of the CO2 stream. Both the nature and the concentrations of potential impurities expected to be present in the CO2 stream of a CCS-integrated power plant depend on not only the type of the power plant but also the carbon capture method used. The present paper focuses on the predictions of impurities expected to be present in the CO2 stream of an oxy-coal combustion plant. The main gaseous impurities of the CO2 stream of oxy-coal combustion are N2/Ar, O2 and H2O. Even the air ingress to the boiler and its auxiliaries is small enough to be neglected, the N2/Ar concentration of the CO2 stream can vary between ca. 1% and 6%, mainly depending on the O2 purity of the air separation unit, and the O2 concentration can vary between ca. 3% and 5%, mainly depending on the combustion stoichiometry of the boiler. The H2O concentration of the CO2 stream can vary from ca. 10% to over 40%, mainly depending on the fuel moisture and the partitioning of recycling flue gas (RFG) between wet-RFG and dry-RFG. NOx and SO2 are the two main polluting impurities of the CO2 stream of an oxy-coal combustion plant and their concentrations are expected to be well above those found in the flue gas of an air-coal combustion plant. The concentration of NOx in the flue gas of an oxy-coal combustion plant can be up to ca. two times to that of an equivalent air-coal combustion plant. The amount of NOx emitted by the oxy-coal combustion plant, however, is expected to be much smaller than that of the air-coal combustion plant. The reductions of the recirculated NOx within the combustion furnace by the reburning

  16. Characterization of Oxy-combustion Impacts in Existing Coal-fired Boilers

    Bradley Adams; Andrew Fry; Constance Senior; Hong Shim; Huafeng Wang; Jost Wendt; Christopher Shaddix

    2009-06-30

    This report summarizes Year 1 results of a research program designed to use multi-scale experimental studies and fundamental theoretical models to characterize and predict the impacts of retrofit of existing coal-fired utility boilers for oxy-combustion. Through the course of Year 1 activities, great progress was made toward understanding the issues associated with oxy-combustion retrofit of coal-fired boilers. All four Year 1 milestones and objectives have been, or will be, completed on schedule and within budget. Progress in the four milestone areas may be summarized as follows: • University of Utah has performed size segregated ash composition measurements in the Oxy-Fuel Combustor (OFC). These experiments indicate that oxy-combustion retrofit may impact ash aerosol mineral matter composition. Both flame temperature and flue gas composition have been observed to influence the concentration of calcium, magnesium and iron in the fine particulate. This could in turn impact boiler fouling and slagging. • Sandia National Labs has shown that char oxidation rate is dependent on particle size (for sizes between 60 and 100 microns) by performing fundamental simulations of reacting char particles. These predictions will be verified by making time-resolved optical measurements of char particle temperature, velocity and size in bench-scale experiments before the end of Year 1. • REI and Siemens have completed the design of an oxy-research burner that will be mounted on University of Utah’s pilot-scale furnace, the L1500. This burner will accommodate a wide range of O2, FGR and mixing strategies under conditions relevant for utility boiler operation. Through CFD modeling of the different burner designs, it was determined that the key factor influencing flame stabilization location is particle heat-up rate. The new oxy-research burner and associated equipment is scheduled for delivery before the end of Year 1. • REI has completed a literature survey of slagging and

  17. Advanced diagnostics in oxy-fuel combustion processes

    Brix, J.; Clausen, Soennik; Degn Jensen, A. (Technical Univ. of Denmark. CHEC Research Centre, Kgs. Lyngby (Denmark)); Boeg Toftegaard, M. (DONG Energy Power, Hvidovre (Denmark))

    2012-07-01

    This report sums up the findings in PSO-project 010069, ''Advanced Diagnostics in Oxy-Fuel Combustion Processes''. Three areas of optic diagnostics are covered in this work: - FTIR measurements in a 30 kW swirl burner. - IR measurements in a 30 kW swirl burner. - IR measurements in a laboratory scale fixed bed reactor. The results obtained in the swirl burner have proved the FTIR method as a valuable technique for gas phase temperature measurements. When its efficacy is evaluated against traditional thermocouple measurements, two cases, with and without probe beam stop, must however be treated separately. When the FTIR probe is operated with the purpose of gas phase concentration measurements the probe needs to operate with a beam stop mounted in front of it. With this beam stop in place it was shown that the measured gas phase temperature was affected by cooling, induced by the cooled beam stop. Hence, for a more accurate determination of gas phase temperatures the probe needed to operate without the beam stop. When this was the case, the FTIR probe showed superior to traditional temperature measurements using a thermocouple as it could measure the fast temperature fluctuations. With the beam stop in place the efficacy of the FTIR probe for gas temperature determination was comparable to the use of a traditional thermocouple. The evaluation of the FTIR technique regarding estimation of gas phase concentrations of H{sub 2}O, CO{sub 2} and CO showed that the method is reliable though it cannot be stated as particularly accurate. The accuracy of the method is dependent on the similarity of the reference emission spectra of the gases with those obtained in the experiments, as the transmittance intensity is not a linear function of concentration. The length of the optical path also affects the steadiness of the measurements. The length of the optical path is difficult to adjust on the small scales that are the focus of this work. However

  18. Tantalum (oxy)nitrides nanotube arrays for the degradation of atrazine in vis-Fenton-like process

    Du, Yingxun, E-mail: yxdu@niglas.ac.cn [Nanjing Institute of Geography and Limnology, State Key Laboratory of Lake Science and Environment, Chinese Academy of Sciences, Nanjing 210008 (China); Zhao, Lu [Nanjing Institute of Geography and Limnology, State Key Laboratory of Lake Science and Environment, Chinese Academy of Sciences, Nanjing 210008 (China); Chang, Yuguang [School of Biochemical and Environmental Engineering, Nanjing Xiaozhuang Univeristy, Nanjing 211171 (China); Su, Yaling [Nanjing Institute of Geography and Limnology, State Key Laboratory of Lake Science and Environment, Chinese Academy of Sciences, Nanjing 210008 (China)

    2012-07-30

    Highlights: Black-Right-Pointing-Pointer Tantala nanotubes on a Ta foil were formed by anodization in a NH{sub 4}F-containing electrolyte. Black-Right-Pointing-Pointer Tantalum (oxy)nitrides nanotubes were active for Fe{sup 3+} reduction under visible light. Black-Right-Pointing-Pointer Atrazine degradation by {center_dot}OH was accelerated with tantalum (oxy)nitrides nanotubes. Black-Right-Pointing-Pointer Tantalum (oxy)nitrides nanotubes display stable performance for atrazine degradation. - Abstract: In order to overcome the limitation of the application of nanoparticles, tantalum (oxy)nitrides nanotube arrays on a Ta foil were synthesized and introduced in vis (visible light)-Fenton-like system to enhance the degradation of atrazine. At first, the anodization of tantalum foil in a mild electrolyte solution containing ethylene glycol and water (v:v = 2:1) plus 0.5 wt.% NH{sub 4}F produced tantala nanotubes with an average diameter of 30 nm and a length of approximately 1 {mu}m. Then the nitridation of tantala nanotube arrays resulted in the replacement of N atoms to O atoms to form tantalum (oxy)nitrides (TaON and Ta{sub 3}N{sub 5}), as testified by XRD and XPS analyses. The synthesized tantalum (oxy)nitrides nanotubes absorb well in the visible region up to 600 nm. Under visible light, tantalum (oxy)nitrides nanotube arrays were catalytically active for Fe{sup 3+} reduction. With tantalum (oxy)nitrides nanotube arrays, the degradation of atrazine and the formation of the intermediates in vis/Fe{sup 3+}/H{sub 2}O{sub 2} system were significantly accelerated. This was explained by the higher concentration of Fe{sup 2+} and thus the faster decomposition of H{sub 2}O{sub 2} with tantalum (oxy)nitrides nanotubes. In addition, tantalum (oxy)nitrides nanotubes exhibited stable performance during atrazine degradation for three runs. The good performance and stability of the tantalum (oxy)nitrides nanotubes film with the convenient separation, suggest that this film is

  19. LES and RANS modeling of pulverized coal combustion in swirl burner for air and oxy-combustion technologies

    Combustion of pulverized coal in oxy-combustion technology is one of the effective ways to reduce the emission of greenhouse gases into the atmosphere. The process of transition from conventional combustion in air to the oxy-combustion technology, however, requires a thorough investigations of the phenomena occurring during the combustion process, that can be greatly supported by numerical modeling. The paper presents the results of numerical simulations of pulverized coal combustion process in swirl burner using RANS (Reynolds-averaged Navier–Stokes equations) and LES (large Eddy simulation) methods for turbulent flow. Numerical simulations have been performed for the oxyfuel test facility located at the Institute of Heat and Mass Transfer at RWTH Aachen University. Detailed analysis of the flow field inside the combustion chamber for cold flow and for the flow with combustion using different numerical methods for turbulent flows have been done. Comparison of the air and oxy-coal combustion process for pulverized coal shows significant differences in temperature, especially close to the burner exit. Additionally the influence of the combustion model on the results has been shown for oxy-combustion test case. - Highlights: • Oxy-coal combustion has been modeled for test facility operating at low oxygen ratio. • Coal combustion process has been modeled with simplified combustion models. • Comparison of oxy and air combustion process of pulverized coal has been done. • RANS (Reynolds-averaged Navier–Stokes equations) and LES (large Eddy simulation) results for pulverized coal combustion process have been compared

  20. Effect of oxy-fuel combustion with steam addition on coal ignition and burnout in an entrained flow reactor

    The ignition temperature and burnout of a semi-anthracite and a high-volatile bituminous coal were studied under oxy-fuel combustion conditions in an entrained flow reactor (EFR). The results obtained under oxy-fuel atmospheres (21%O2-79%CO2, 30%O2-70% O2 and 35%O2-65%CO2) were compared with those attained in air. The replacement of CO2 by 5, 10 and 20% of steam in the oxy-fuel combustion atmospheres was also evaluated in order to study the wet recirculation of flue gas. For the 21%O2-79%CO2 atmosphere, the results indicated that the ignition temperature was higher and the coal burnout was lower than in air. However, when the O2 concentration was increased to 30 and 35% in the oxy-fuel combustion atmosphere, the ignition temperature was lower and coal burnout was improved in comparison with air conditions. On the other hand, an increase in ignition temperature and a worsening of the coal burnout was observed when steam was added to the oxy-fuel combustion atmospheres though no relevant differences between the different steam concentrations were detected. -- Highlights: → The ignition temperature and the burnout of two thermal coals under oxy-fuel combustion conditions were determined. → The effect of the wet recirculation of flue gas on combustion behaviour was evaluated. → Addition of steam caused a worsening of the ignition temperature and coal burnout.

  1. Coal-Based Oxy-Fuel System Evaluation and Combustor Development; Oxy-Fuel Turbomachinery Development for Energy Intensive Industrial Applications

    Hollis, Rebecca

    2013-03-31

    Clean Energy Systems, Inc. (CES) partnered with the U.S. Department of Energy’s National Energy Technology Laboratory in 2005 to study and develop a competing technology for use in future fossil-fueled power generation facilities that could operate with near zero emissions. CES’s background in oxy-fuel (O-F) rocket technology lead to the award of Cooperative Agreement DE-FC26-05NT42645, “Coal-Based Oxy-Fuel System Evaluation and Combustor Development,” where CES was to first evaluate the potential of these O-F power cycles, then develop the detailed design of a commercial-scale O-F combustor for use in these clean burning fossil-fueled plants. Throughout the studies, CES found that in order to operate at competitive cycle efficiencies a high-temperature intermediate pressure turbine was required. This led to an extension of the Agreement for, “Oxy-Fuel Turbomachinery Development for Energy Intensive Industrial Applications” where CES was to also develop an intermediate-pressure O-F turbine (OFT) that could be deployed in O-F industrial plants that capture and sequester >99% of produced CO2, at competitive cycle efficiencies using diverse fuels. The following report details CES’ activities from October 2005 through March 2013, to evaluate O-F power cycles, develop and validate detailed designs of O-F combustors (main and reheat), and to design, manufacture, and test a commercial-scale OFT, under the three-phase Cooperative Agreement.

  2. Brain Activity Evaluation Using Oxy-Hb by Difference in the Strength of Sound Stimulus

    Osawa, Takeru; Asano, Hirotoshi; Ide, Hideto

    We carried out a psychological study involving physiological measurements. We used the VAS to research the feeling. The physiological factor measured was the oxy-Hb. It was found that an auditory stimulus of 70[dB] is more uncomfortable than auditory stimulus of 50[dB]. Furthermore, the decrease in oxy-Hb was greater for the auditory stimulus of 70[dB] as compared to the auditory stimulus of 50[dB]. This tendency was found in the center of the forehead (ch22-ch25). There was a difference between the brain activity for the auditory stimulus of 70[dB] and that for the auditory stimulus of 50[dB]. It was also found that the sound level affects the comfort level of humans. It is necessary to obtain additional details on the effects from physiological index to psychological index in a future study.

  3. Developments in integrated pollutant removal for low-emission oxy-fuel combustion

    Gerdemann, Stephen J.; Summers, Cathy A.; Oryshchyn, Danylo B.; Patrick, Brian (Jupiter Oxygen Corp.); Ochs, Thomas L.

    2005-09-01

    A complete coal combustion and flue gas treatment scheme was designed, constructed, and operated at bench scale as a product of cooperative research between US DOE’s Albany Research Center (ARC) and Jupiter Oxygen Corporation. The combustion gas generated using this oxy-fuel coal combustion process was effectively captured using an integrated pollutant removal (IPR) process. Supporting laboratory-scale research focuses on elements of IPR such as extraction of particulates, SO2, and mercury, and on the character of the liquid and vapor phase compositions for the CO2 - N2 - O2 mixture at the temperature and pressure conditions found at the end of the process. Future pilot-scale work will be necessary to generate economic and engineering data that will apply to full-scale oxy-fuel/IPR systems.

  4. Chemical effects of a high CO2 concentration in oxy-fuel combustion of methane

    Glarborg, Peter; Bentzen, L.L.B.

    2008-01-01

    The oxidation of methane in an atmospheric-pres sure flow reactor has been studied experimentally under highly diluted conditions in N-2 and CO2, respectively. The stoichiometry was varied from fuel-lean to fuel-rich, and the temperatures covered the range 1200-1800 K. The results were interpreted...... in terms of a detailed chemical kinetic mechanism for hydrocarbon oxidation. On the basis of results of the present study, it can be expected that oxy-fuel combustion will lead to strongly increased CO concentrations in the near-burner region. The CO2 present will compete with O-2 for atomic hydrogen...... consuming CO2. The high local CO levels may have implications for near-burner corrosion and stagging, but increased problems with CO emission in oxy-fuel combustion are not anticipated....

  5. Analysis of the Transition Time From Air to Oxy-Combustion

    Lasek Janusz

    2015-03-01

    Full Text Available In this paper some issues of the transition process from air- to oxy-combustion were investigated. Advantages of flexible combustion were described. Flexible combustion tests carried out at four European plants and five plants outside Europe of different scales of process and test parameters were presented. An analysis of the transition time from air to oxy-combustion of different laboratory and pilot scale processes was carried out. The “first-order + dead time” approach was used as a model to describe transition process. Transitional periods between combustion modes and characteristic parameters of the process were determined. The transition time depends not only on the facility’s capacity but also it is impacted by specific operational parameters.

  6. The effect of oxidant flow rate on a coaxial oxy-fuel flame

    Hashemi, S. A.; Fattahi, A.; Sheikhzadeh, G. A.; Mehrabian, M. A.

    2012-09-01

    The effect of oxidant flow rate on temperature, heat transfer, and NOx formation of an oxy-fuel flame is investigated using numerical simulation. The finite volume approach is used to solve the governing equations. The realizable k-ɛ turbulence model and β-PDF model are adopted to simulate the turbulence-combustion interaction. There is a good agreement between the present numerical results and the reference experimental data. The exhaust temperature is decreased with decreasing the oxidant inlet flow rate. As an important result, the adiabatic flame temperature can be considered a key parameter in the oxy-fuel flame applications. Also, it is observed that increasing oxygen inlet angle causes a decrease in NO formation.

  7. Simultaneous carbonation and sulfation of CaO in Oxy-Fuel CFB combustion

    Wang, C. [School of Energy and Power Engineering, North China Electric Power University, Baoding City, Hebei Province (China); Jia, L.; Tan, Y. [CanmetENERGY, 1 Haanel Drive, Ottawa, Ontario, K1A 1M1 (Canada)

    2011-10-15

    For anthracites and petroleum cokes, the typical combustion temperature in a circulating fluidized bed (CFB) is > 900 C. At CO{sub 2} concentrations of 80-85 % (typical of oxy-fuel CFBC conditions), limestone still calcines. When the ash which includes unreacted CaO cools to the calcination temperature, carbonation of fly ash deposited on cool surfaces may occur. At the same time, indirect and direct sulfation of limestone also will occur, possibly leading to more deposition. In this study, CaO was carbonated and sulfated simultaneously in a thermogravimetric analyzer (TGA) under conditions expected in an oxy-fuel CFBC. It was found that temperature, and concentrations of CO{sub 2}, SO{sub 2}, and especially H{sub 2}O are important factors in determining the carbonation/sulfation reactions of CaO. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  8. Characteristics modeling for supercritical circulating fluidized bed boiler working in oxy-combustion technology

    Balicki, Adrian; Bartela, Łukasz

    2014-06-01

    Among the technologies which allow to reduce greenhouse gas emission, mainly carbon dioxide, special attention deserves the idea of `zeroemission' technology based on boilers working in oxy-combustion technology. In the paper the results of analyses of the influence of changing two quantities, namely oxygen share in oxidant produced in the air separation unit, and oxygen share in oxidant supplied to the furnace chamber on the selected characteristics of a steam boiler including the degree of exhaust gas recirculation, boiler efficiency and adiabatic flame temperature, was examined. Due to the possibility of the integration of boiler model with carbon dioxide capture, separation and storage installation, the subject of the analysis was also to determine composition of the flue gas at the outlet of a moisture condensation installation. Required calculations were made using a model of a supercritical circulating fluidized bed boiler working in oxy-combustion technology, which was built in a commercial software and in-house codes.

  9. Oxy-Combustion Environment Characterization: Fire- and Steam-Side Corrosion in Advanced Combustion

    G. R. Holcomb; J. Tylczak; G. H. Meier; B. S. Lutz; N. M. Yanar; F. S. Pettit; J. Zhu; A. Wise; D. E. Laughlin; S. Sridhar

    2012-09-25

    Oxy-fuel combustion is burning a fuel in oxygen rather than air. The low nitrogen flue gas that results is relatively easy to capture CO{sub 2} from for reuse or sequestration. Corrosion issues associated with the environment change (replacement of much of the N{sub 2} with CO{sub 2} and higher sulfur levels) from air- to oxy-firing were examined. Alloys studied included model Fe-Cr alloys and commercial ferritic steels, austenitic steels, and nickel base superalloys. The corrosion behavior is described in terms of corrosion rates, scale morphologies, and scale/ash interactions for the different environmental conditions. Additionally, the progress towards laboratory oxidation tests in advanced ultra-supercritical steam is updated.

  10. Determination of polycyclic aromatic hydrocarbons and their oxy-, nitro-, and hydroxy-oxidation products

    Highlights: ► We describe a method for determining PAHs and their oxidation products. ► Solid-phase extraction was used to fractionate PAHs and their oxidation products. ► Gas chromatography–mass spectrometry methods were optimized. ► The developed method was applied to two particulate matter (PM) samples. - Abstract: A sensitive method has been developed for the trace analysis of PAHs and their oxidation products (i.e., nitro-, oxy-, and hydroxy-PAHs) in air particulate matter (PM). Following PM extraction, PAHs, nitro-, oxy-, and hydroxy-PAHs were fractionated using solid phase extraction (SPE) based on their polarities. Gas chromatography–mass spectrometry (GC–MS) conditions were optimized, addressing injection (i.e., splitless time), negative-ion chemical ionization (NICI) parameters, i.e., source temperature and methane flow rate, and MS scanning conditions. Each class of PAH oxidation products was then analyzed using the sample preparation and appropriate ionization conditions (e.g., nitro-PAHs exhibited the greatest sensitivity when analyzed with NICI–MS while hydroxy-PAHs required chemical derivatization prior to GC–MS analysis). The analyses were performed in selected-ion-total-ion (SITI) mode, combining the increased sensitivity of selected-ion monitoring (SIM) with the identification advantages of total-ion current (TIC). The instrumental LODs determined were 6–34 pg for PAHs, 5–36 pg for oxy-PAHs, and 1–21 pg for derivatized hydroxy-PAHs using electron ionization (GC-EI-MS). NICI–MS was found to be a useful tool for confirming the tentative identification of oxy-PAHs. For nitro-PAHs, LODs were 1–10 pg using negative-ion chemical ionization (GC-NICI-MS). The developed method was successfully applied to two types of real-world PM samples, diesel exhaust standard reference material (SRM 2975) and wood smoke PM.

  11. Technical and economic aspects of oxygen separation for oxy-fuel purposes

    Chorowski Maciej; Gizicki Wojciech

    2015-01-01

    Oxy combustion is the most promising technology for carbon dioxide, originated from thermal power plants, capture and storage. The oxygen in sufficient quantities can be separated from air in cryogenic installations. Even the state-of-art air separation units are characterized by high energy demands decreasing net efficiency of thermal power plant by at least 7%. This efficiency decrease can be mitigated by the use of waste nitrogen, e.g., as the medium for lignite drying. It is also possible...

  12. A Model for Nitrogen Chemistry in Oxy-Fuel Combustion of Pulverized Coal

    Hashemi, Hamid; Hansen, Stine; Toftegaard, Maja Bøg; Pedersen, Kim Hougaard; Jensen, Anker Degn; Dam-Johansen, Kim; Glarborg, Peter

    2011-01-01

    In this work, a model for the nitrogen chemistry in the oxy-fuel combustion of pulverized coal has been developed. The model is a chemical reaction engineering type of model with a detailed reaction mechanism for the gas-phase chemistry, together with a simplified description of the mixing of flows, heating and devolatilization of particles, and gas–solid reactions. The model is validated by comparison with entrained flow reactor results from the present work and from the literature on pulver...

  13. Optimization and Characterization of High Velocity Oxy-fuel Sprayed Coatings: Techniques, Materials, and Applications

    Maria Oksa; Erja Turunen; Tomi Suhonen; Tommi Varis; Simo-Pekka Hannula

    2011-01-01

    In this work High Velocity Oxy-fuel (HVOF) thermal spray techniques, spraying process optimization, and characterization of coatings are reviewed. Different variants of the technology are described and the main differences in spray conditions in terms of particle kinetics and thermal energy are rationalized. Methods and tools for controlling the spray process are presented as well as their use in optimizing the coating process. It will be shown how the differences from the starting powder to ...

  14. Investigating the combustion characteristic temperature of 28 kinds of Chinese coal in oxy-fuel conditions

    Highlights: • 28 kinds of Chinese coal combustion in O2/CO2 atmosphere are investigated. • The relation between coal properties and characteristic temperature is studied. • The oxidation regime under different O2 concentration is investigated. • The coal with higher fixed carbon or ash is easily affected by O2 in ignition. • The coal with lower O/C or H/C is significantly affected by O2 concentration. - Abstract: Oxy-fuel combustion is widely considered to be the most promising potential CO2 capture technology. In this study, the combustion characteristic temperatures of 28 kinds of Chinese coals were investigated under three O2 concentrations of oxy-fuel through the non-isothermal thermo-gravimetric analysis. Three characteristic temperatures (ignition temperature, temperature at the maximum reactivity rate, and burnout temperature) were obtained from the experimental curve. The pulverized coal was also described through proximate analysis and ultimate analyses. The relationship between coal properties and characteristic temperature was investigated with the linear fitting method. Furthermore, the influences of coal properties on oxy-coal combustion were studied according to the close link between two slopes under different O2 concentrations. Similarly, the influences of oxidation regimes can be inferred by comparing the trends of characteristic temperature under various O2 concentrations. The mechanisms were studied in detail by analysing the carbon crystal structure and the ash element. Finally, the coal easy to be affected by O2 concentration was identified, and the main control regimes under different conditions were distinguished. The research results show important significance in the industrial application of oxy-fuel combustion technology

  15. High velocity oxy-fuel (HVOF) thermal spray deposition of functionally graded coatings

    Mahbub, Hasan

    2005-01-01

    The present study investigates an innovative modification of a HVOF (High Velocity Oxy-Fuel) thermal spray process to produce functionally graded thick coatings. In order to deposit thick coatings, certain problems have to be overcome. More specifically these problems include minimizing residual stresses, which cause shape distortion in assprayed components. Residual stresses in coatings also lead to adhesion loss, interlaminar debonding, cracking or buckling and are particularly high where t...

  16. Crystallization and diffraction patterns of the oxy and cyano forms of the Lucina pectinata haemoglobins complex

    The native oxygen-carrier haemoglobins complex (HbII–III) is composed of haemoglobin II (HbII) and haemoglobin III (HbIII), which are found in the ctenidia tissue of the bivalve mollusc Lucina pectinata. This protein complex was isolated and purified from its natural source and crystallized using the vapour-diffusion and capillary counter-diffusion methods. The native oxygen-carrier haemoglobins complex (HbII–III) is composed of haemoglobin II (HbII) and haemoglobin III (HbIII), which are found in the ctenidia tissue of the bivalve mollusc Lucina pectinata. This protein complex was isolated and purified from its natural source and crystallized using the vapour-diffusion and capillary counter-diffusion methods. Oxy and cyano derivatives of the complex crystallized using several conditions, but the best crystals in terms of quality and size were obtained from sodium formate pH 5 using the counter-diffusion method in a single capillary. Crystals of the oxy and cyano complexes, which showed a ruby-red colour and nonsingular prismatic shapes, scattered X-rays to resolution limits of 2.15 and 2.20 Å, respectively, using a 0.886 Å synchrotron-radiation source. The crystals belonged to the tetragonal system, space group P42212, with unit-cell parameters a = b = 74.07, c = 152.07 and a = b = 73.83, c = 152.49 Å for the oxy and cyano complexes, respectively. The asymmetric unit of both crystals is composed of a single copy of the heterodimer, with Matthew coefficients (VM) of 3.08 and 3.06 Å3 Da−1 for the oxy and cyano complexes, respectively, which correspond to a solvent content of approximately 60.0% by volume

  17. Oxy-acetylene driven laboratory scale shock tubes for studying blast wave effects

    Courtney, Amy; Andrusiv, Lubov; Courtney, Michael

    2011-01-01

    This paper describes the development and characterization of modular, oxy-acetylene driven laboratory scale shock tubes. Such tools are needed to produce realistic blast waves in a laboratory setting. The pressure-time profiles measured at 1 MHz using high speed piezoelectric pressure sensors have relevant durations and show a true shock front and exponential decay characteristic of free-field blast waves. Descriptions are included for shock tube diameters of 27 - 79 mm. A range of peak press...

  18. Characterization of OxyR as a negative transcriptional regulator that represses catalase production in Corynebacterium diphtheriae.

    Kim, Ju-Sim; Holmes, Randall K

    2012-01-01

    Corynebacterium diphtheriae and Corynebacterium glutamicum each have one gene (cat) encoding catalase. In-frame Δcat mutants of C. diphtheriae and C. glutamicum were hyper-sensitive to growth inhibition and killing by H(2)O(2). In C. diphtheriae C7(β), both catalase activity and cat transcription decreased ~2-fold during transition from exponential growth to early stationary phase. Prototypic OxyR in Escherichia coli senses oxidative stress and it activates katG transcription and catalase production in response to H(2)O(2). In contrast, exposure of C. diphtheriae C7(β) to H(2)O(2) did not stimulate transcription of cat. OxyR from C. diphtheriae and C. glutamicum have 52% similarity with E. coli OxyR and contain homologs of the two cysteine residues involved in H(2)O(2) sensing by E. coli OxyR. In-frame ΔoxyR deletion mutants of C. diphtheriae C7(β), C. diphtheriae NCTC13129, and C. glutamicum were much more resistant than their parental wild type strains to growth inhibition by H(2)O(2). In the C. diphtheriae C7(β) ΔoxyR mutant, cat transcripts were about 8-fold more abundant and catalase activity was about 20-fold greater than in the C7(β) wild type strain. The oxyR gene from C. diphtheriae or C. glutamicum, but not from E. coli, complemented the defect in ΔoxyR mutants of C. diphtheriae and C. glutamicum and decreased their H(2)O(2) resistance to the level of their parental strains. Gel-mobility shift, DNaseI footprint, and primer extension assays showed that purified OxyR from C. diphtheriae C7(β) bound, in the presence or absence of DTT, to a sequence in the cat promoter region that extends from nucleotide position -55 to -10 with respect to the +1 nucleotide in the cat ORF. These results demonstrate that OxyR from C. diphtheriae or C. glutamicum functions as a transcriptional repressor of the cat gene by a mechanism that is independent of oxidative stress induced by H(2)O(2). PMID:22438866

  19. Characterization of OxyR as a negative transcriptional regulator that represses catalase production in Corynebacterium diphtheriae.

    Ju-Sim Kim

    Full Text Available Corynebacterium diphtheriae and Corynebacterium glutamicum each have one gene (cat encoding catalase. In-frame Δcat mutants of C. diphtheriae and C. glutamicum were hyper-sensitive to growth inhibition and killing by H(2O(2. In C. diphtheriae C7(β, both catalase activity and cat transcription decreased ~2-fold during transition from exponential growth to early stationary phase. Prototypic OxyR in Escherichia coli senses oxidative stress and it activates katG transcription and catalase production in response to H(2O(2. In contrast, exposure of C. diphtheriae C7(β to H(2O(2 did not stimulate transcription of cat. OxyR from C. diphtheriae and C. glutamicum have 52% similarity with E. coli OxyR and contain homologs of the two cysteine residues involved in H(2O(2 sensing by E. coli OxyR. In-frame ΔoxyR deletion mutants of C. diphtheriae C7(β, C. diphtheriae NCTC13129, and C. glutamicum were much more resistant than their parental wild type strains to growth inhibition by H(2O(2. In the C. diphtheriae C7(β ΔoxyR mutant, cat transcripts were about 8-fold more abundant and catalase activity was about 20-fold greater than in the C7(β wild type strain. The oxyR gene from C. diphtheriae or C. glutamicum, but not from E. coli, complemented the defect in ΔoxyR mutants of C. diphtheriae and C. glutamicum and decreased their H(2O(2 resistance to the level of their parental strains. Gel-mobility shift, DNaseI footprint, and primer extension assays showed that purified OxyR from C. diphtheriae C7(β bound, in the presence or absence of DTT, to a sequence in the cat promoter region that extends from nucleotide position -55 to -10 with respect to the +1 nucleotide in the cat ORF. These results demonstrate that OxyR from C. diphtheriae or C. glutamicum functions as a transcriptional repressor of the cat gene by a mechanism that is independent of oxidative stress induced by H(2O(2.

  20. Near-Zero Emissions Oxy-Combustion Flue Gas Purification

    Minish Shah; Nich Degenstein; Monica Zanfir; Rahul Solunke; Ravi Kumar; Jennifer Bugayong; Ken Burgers

    2012-06-30

    The objectives of this project were to carry out an experimental program to enable development and design of near zero emissions (NZE) CO{sub 2} processing unit (CPU) for oxy-combustion plants burning high and low sulfur coals and to perform commercial viability assessment. The NZE CPU was proposed to produce high purity CO{sub 2} from the oxycombustion flue gas, to achieve > 95% CO{sub 2} capture rate and to achieve near zero atmospheric emissions of criteria pollutants. Two SOx/NOx removal technologies were proposed depending on the SOx levels in the flue gas. The activated carbon process was proposed for power plants burning low sulfur coal and the sulfuric acid process was proposed for power plants burning high sulfur coal. For plants burning high sulfur coal, the sulfuric acid process would convert SOx and NOx in to commercial grade sulfuric and nitric acid by-products, thus reducing operating costs associated with SOx/NOx removal. For plants burning low sulfur coal, investment in separate FGD and SCR equipment for producing high purity CO{sub 2} would not be needed. To achieve high CO{sub 2} capture rates, a hybrid process that combines cold box and VPSA (vacuum pressure swing adsorption) was proposed. In the proposed hybrid process, up to 90% of CO{sub 2} in the cold box vent stream would be recovered by CO{sub 2} VPSA and then it would be recycled and mixed with the flue gas stream upstream of the compressor. The overall recovery from the process will be > 95%. The activated carbon process was able to achieve simultaneous SOx and NOx removal in a single step. The removal efficiencies were >99.9% for SOx and >98% for NOx, thus exceeding the performance targets of >99% and >95%, respectively. The process was also found to be suitable for power plants burning both low and high sulfur coals. Sulfuric acid process did not meet the performance expectations. Although it could achieve high SOx (>99%) and NOx (>90%) removal efficiencies, it could not produce by

  1. Pyrolysis and oxy-fuel combustion characteristics and kinetics of petrochemical wastewater sludge using thermogravimetric analysis.

    Chen, Jianbiao; Mu, Lin; Cai, Jingcheng; Yao, Pikai; Song, Xigeng; Yin, Hongchao; Li, Aimin

    2015-12-01

    The pyrolysis and oxy-fuel combustion characteristics of petrochemical wastewater sludge (PS) were studied in air (O2/N2) and oxy-fuel (O2/CO2) atmospheres using non-isothermal thermogravimetric analysis (TGA). Pyrolysis experiments showed that the weight loss profiles were almost similar up to 1050K in both N2 and CO2 atmospheres, while further weight loss took place in CO2 atmosphere at higher temperatures due to char-CO2 gasification. Compared with 20%O2/80%N2, the drying and devolatilization stage of PS were delayed in 20%O2/80%CO2 due to the differences in properties of the diluting gases. In oxy-fuel combustion experiments, with O2 concentration increasing, characteristic temperatures decreased, while characteristic combustion rates and combustion performance indexes increased. Kinetic analysis of PS decomposition under various atmospheres was performed using Coats-Redfern approach. The results indicated that, with O2 concentration increasing, the activation energies of Step 1 almost kept constant, while the values of subsequent three steps increased. PMID:26386413

  2. Effects of flue gas recycle on oxy-coal power generation systems

    Highlights: ► Air-coal and oxy-coal combustion systems were simulated in Aspen Plus. ► Various options concerning emission removal in oxy-coal systems were assessed. ► Performance analysis was conducted to understand the impacts of those options. -- Abstract: This paper examined and assessed various configuration options about emission removal including particles, SOx and NOx in an oxy-coal combustion system for CO2 capture. A performance analysis was conducted in order to understand the impacts of those options concerning process design, process operation and system efficiency. Results show that different flue gas recycle options have clear effects on the emissivity and absorptivity of radiating gases in boiler due to the change of flue gas compositions. The maximum difference amongst various options can be up to 15% and 20% for emissivity and absorptivity respectively. As a result, the heat transfer by radiation can vary about 20%. The recycle options also have impacts on the design of air heater and selective-catalytic-reduction (SCR) preheater. This is due to that the largely varied operating temperatures in different options may result in different required areas of heat exchangers. In addition, the dew point of flue gas and the boiler efficiency are affected by the configurations of flue gas recycle as well.

  3. Higher Molecular Mass Organic Matter Molecules Compete with Orthophosphate for Adsorption to Iron (Oxy)hydroxide.

    Chassé, Alexander W; Ohno, Tsutomu

    2016-07-19

    The competition between orthophosphate and water-extractable organic matter (WEOM) for adsorption to iron (oxy)hydroxide mineral surfaces is an important factor in determining the plant bioavailability of P in soils. Chemical force spectroscopy was used to determine the binding force between orthophosphate and iron (oxy)hydroxide that was coated onto atomic force microscopy (AFM) tips and adsorbed with WEOM. The force measurements were conducted at pH 4.65 and 0.02 M ionic strength which are representative of typical acid soil solutions. The chemical composition of the WEOM was determined by ultrahigh resolution electrospray ionization Fourier transform ion cyclotron mass spectrometry. The results indicate a correlation between aromatic WEOM molecules that are greater than 600 Da and the reduced binding force of orthophosphate to WEOM-adsorbed iron (oxy)hydroxide AFM tips suggesting that the molecular mass of aromatic WEOM molecules plays a critical role in regulating the WEOM-P interactions with surface functional groups of minerals. Based on the results of this study, we show the importance of obtaining a detailed, molecular-scale understanding of soil processes that can help develop better management strategies to reduce waste of limited P resources and adverse environmental impacts. Specifically, soil amendments with greater content of high molecular mass aromatic components may positively affect dissolved P use efficiency in soils by maintaining P in soil solution. PMID:27362894

  4. The role of SO42- surface distribution in arsenic removal by iron oxy-hydroxides

    Tresintsi, S.; Simeonidis, K.; Pliatsikas, N.; Vourlias, G.; Patsalas, P.; Mitrakas, M.

    2014-05-01

    This study investigates the contribution of chemisorbed SO42- in improving arsenic removal properties of iron oxy-hydroxides through an ion-exchange mechanism. An analytical methodology was developed for the accurate quantification of sulfate ion (SO42-) distribution onto the surface and structural compartments of iron oxy-hydroxides synthesized by FeSO4 precipitation. The procedure is based on the sequential determination of SO42- presence in the diffuse and Stern layers, and the structure of these materials as defined by the sulfate-rich environments during the reaction and the variation in acidity (pH 3-12). Physically sorbed SO42-, extracted in distilled water, and physically/chemically adsorbed ions on the oxy-hydroxide's surface leached by a 5 mM NaOH solution, were determined using ion chromatography. Total sulfate content was gravimetrically measured by precipitation as BaSO4. To validate the suggested method, results were verified by X-ray photoelectron and Fourier-transformed infrared spectroscopy. Results showed that low precipitation pH-values favor the incorporation of sulfate ions into the structure and the inner double layer, while under alkaline conditions ions shift to the diffuse layer.

  5. Soot, unburned carbon and ultrafine particle emissions from air- and oxy-coal flames

    Oxy-coal combustion is one possible solution for the mitigation of greenhouse gases. In this process coal is burned in oxygen, rather than air, and the temperatures in the boiler are mitigated by recycling flue gases, so that the inlet mixture may contain either 27 % O2 to match adiabatic flame temperatures, or 32 % O2 to match gaseous radiation heat fluxes in the combustion chamber. However, a major issue for heat transfer from coal combustion is the radiative heat transmission from soot. For this research, air and oxy coal firing were compared regarding the emission of soot. A 100 kW down-fired laboratory combustor was used to determine effects of switching from air to oxy-firing on soot, unburned carbon and ultrafine particle emissions from practical pulverized coal flames. Of interest here were potential chemical effects of substitution of the N2 in air by CO2 in practical pulverized coal flames. The oxy-coal configuration investigated used once-through CO2, simulating cleaned flue gas recycle with all contaminants and water removed. Three coals were each burned in: a) air, b) 27 % O2/ 73 % CO2, c) 32 % O2/ 68 % CO2. Tests were conducted at (nominally) 3 %, 2 %, 1 % and 0 % O2 in the exhaust (dry basis). For each condition, particulate samples were iso kinetically withdrawn far from the radiant zone, and analyzed using a photoacoustic analyzer (PA) for black carbon, a scanning mobility particle sizer (SMPS) for ultrafine particles, and a total sample loss on ignition (LOI) method for unburned carbon in ash. Data suggest that at low stoichiometric ratios, ultrafine particles consist primarily of black carbon, which, for the bituminous coal, is produced in lesser amounts under oxy-fired conditions than under the air-fired condition, even when adiabatic flame temperatures are matched. However, significant changes in mineral matter vaporization were not observed unless the flames were hotter. These and other results are interpreted in the light of available

  6. Transcriptional response of Corynebacterium glutamicum ATCC 13032 to hydrogen peroxide stress and characterization of the OxyR regulon.

    Milse, Johanna; Petri, Kathrin; Rückert, Christian; Kalinowski, Jörn

    2014-11-20

    The aerobic soil bacterium Corynebacterium glutamicum ATCC 13032 has a remarkable natural resistance to hydrogen peroxide. A major player in hydrogen peroxide defense is the LysR type transcriptional regulator OxyR, homologs of which are present in a wide range of bacteria. In this study, the global transcriptional response of C. glutamicum to oxidative stress induced by hydrogen peroxide was examined using whole genome DNA microarrays, demonstrating the dynamic reaction of the regulatory networks. Deletion of oxyR resulted in an increased resistance of the C. glutamicum mutant to hydrogen peroxide. By performing DNA microarray hybridizations and RT-qPCR, differentially expressed genes were detected in the mutant. The direct control by OxyR was verified by electrophoretic mobility shift assays for 12 target regions. The results demonstrated that OxyR in C. glutamicum acts as a transcriptional repressor under non-stress conditions for a total of 23 genes. The regulated genes encode proteins related to oxidative stress response (e.g. katA), iron homeostasis (e.g. dps) and sulfur metabolism (e.g. suf cluster). Besides the regulator of the suf cluster, SufR, OxyR regulated the gene cg1695 encoding a putative transcriptional regulator, indicating the role of OxyR as a master regulator in defense against oxidative stress. Using a modified DNase footprint approach, the OxyR-binding sites in five target promoter regions, katA, cydA, hemH, dps and cg1292, were localized and in each upstream region at least two overlapping binding sites were found. The DNA regions protected by the OxyR protein are about 56bp in length and do not have evident sequence similarities. Still, by giving an insight in the H2O2 stimulon and extending the OxyR regulon this study considerably contributes to the understanding of the response of C. glutamicum to hydrogen peroxide-mediated oxidative stress. PMID:25107507

  7. Process analysis of an oxygen lean oxy-fuel power plant with co-production of synthesis gas

    This paper investigates new possibilities and synergy effects for an oxy-fuel fired polygeneration scheme (transportation fuel and electricity) with carbon capture and co-firing of biomass. The proposed process has the potential to make the oxy-fuel process more effective through a sub-stoichiometric combustion in-between normal combustion and gasification, which lowers the need for oxygen within the process. The sub-stoichiometric combustion yields production of synthesis gas, which is utilised in an integrated synthesis to dimethyl ether (DME). The process is kept CO2 neutral through co-combustion of biomass in the process. The proposed scheme is simulated with a computer model with a previous study of an oxy-fuel power plant as a reference process. The degree of sub-stoichiometric combustion, or amount of synthesis gas produced, is optimised with respect to the overall efficiency. The maximal efficiency was found at a stoichiometric ratio just below 0.6 with the efficiency for the electricity producing oxy-fuel process of 0.35 and a DME process efficiency of 0.63. It can be concluded that the proposed oxygen lean combustion process constitutes a way to improve the oxy-fuel carbon capture processes with an efficient production of DME in a polygeneration process

  8. Oxy-fuel Combustion and Integrated Pollutant Removal as Retrofit Technologies for Removing CO2 from Coal Fired Power Plants

    Ochs, T.L.; Oryshchyn, D.B.; Summers, C.A.; Gerdemann, S.J.

    2001-01-01

    One third of the US installed capacity is coal-fired, producing 49.7% of net electric generation in 20051. Any approach to curbing CO2 production must consider the installed capacity and provide a mechanism for preserving this resource while meeting CO2 reduction goals. One promising approach to both new generation and retrofit is oxy-fuel combustion. Using oxygen instead of air as the oxidizer in a boiler provides a concentrated CO2 combustion product for processing into a sequestration-ready fluid.... Post-combustion carbon capture and oxy-fuel combustion paired with a compression capture technology such as IPR are both candidates for retrofitting pc combustion plants to meet carbon emission limits. This paper will focus on oxy-fuel combustion as applied to existing coal power plants.

  9. Next Generation Pressurized Oxy-Coal Combustion: High Efficiency and No Flue Gas Recirculation

    Rue, David

    2013-09-30

    The Gas Technology Institute (GTI) has developed a pressurized oxy-coal fired molten bed boiler (MBB) concept, in which coal and oxygen are fired directly into a bed of molten coal slag through burners located on the bottom of the boiler and fired upward. Circulation of heat by the molten slag eliminates the need for a flue gas recirculation loop and provides excellent heat transfer to steam tubes in the boiler walls. Advantages of the MBB technology over other boilers include higher efficiency (from eliminating flue gas recirculation), a smaller and less expensive boiler, modular design leading to direct scalability, decreased fines carryover and handling costs, smaller exhaust duct size, and smaller emissions control equipment sizes. The objective of this project was to conduct techno-economic analyses and an engineering design of the MBB project and to support this work with thermodynamic analyses and oxy-coal burner testing. Techno-economic analyses of GTI’s pressurized oxy-coal fired MBB technology found that the overall plant with compressed CO2 has an efficiency of 31.6%. This is a significant increase over calculated 29.2% efficiency of first generation oxy-coal plants. Cost of electricity (COE) for the pressurized MBB supercritical steam power plant with CO2 capture and compression was calculated to be 134% of the COE for an air-coal supercritical steam power plant with no CO2 capture. This compares positively with a calculated COE for first generation oxy-coal supercritical steam power plants with CO2 capture and compression of 164%. The COE for the MBB power plant is found to meet the U.S. Department of Energy (DOE) target of 135%, before any plant optimization. The MBB power plant was also determined to be simpler than other oxy-coal power plants with a 17% lower capital cost. No other known combustion technology can produce higher efficiencies or lower COE when CO2 capture and compression are included. A thermodynamic enthalpy and exergy analysis

  10. FutureGen 2.0 Oxy-combustion Large Scale Test – Final Report

    Kenison, LaVesta [URS, Pittsburgh, PA (United States); Flanigan, Thomas [URS, Pittsburgh, PA (United States); Hagerty, Gregg [URS, Pittsburgh, PA (United States); Gorrie, James [Air Liquide, Kennesaw, GA (United States); Leclerc, Mathieu [Air Liquide, Kennesaw, GA (United States); Lockwood, Frederick [Air Liquide, Kennesaw, GA (United States); Falla, Lyle [Babcock & Wilcox and Burns McDonnell, Kansas City, MO (United States); Macinnis, Jim [Babcock & Wilcox and Burns McDonnell, Kansas City, MO (United States); Fedak, Mathew [Babcock & Wilcox and Burns McDonnell, Kansas City, MO (United States); Yakle, Jeff [Babcock & Wilcox and Burns McDonnell, Kansas City, MO (United States); Williford, Mark [Futuregen Industrial Alliance, Inc., Morgan County, IL (United States); Wood, Paul [Futuregen Industrial Alliance, Inc., Morgan County, IL (United States)

    2016-04-01

    The primary objectives of the FutureGen 2.0 CO2 Oxy-Combustion Large Scale Test Project were to site, permit, design, construct, and commission, an oxy-combustion boiler, gas quality control system, air separation unit, and CO2 compression and purification unit, together with the necessary supporting and interconnection utilities. The project was to demonstrate at commercial scale (168MWe gross) the capability to cleanly produce electricity through coal combustion at a retrofitted, existing coal-fired power plant; thereby, resulting in near-zeroemissions of all commonly regulated air emissions, as well as 90% CO2 capture in steady-state operations. The project was to be fully integrated in terms of project management, capacity, capabilities, technical scope, cost, and schedule with the companion FutureGen 2.0 CO2 Pipeline and Storage Project, a separate but complementary project whose objective was to safely transport, permanently store and monitor the CO2 captured by the Oxy-combustion Power Plant Project. The FutureGen 2.0 Oxy-Combustion Large Scale Test Project successfully achieved all technical objectives inclusive of front-end-engineering and design, and advanced design required to accurately estimate and contract for the construction, commissioning, and start-up of a commercial-scale "ready to build" power plant using oxy-combustion technology, including full integration with the companion CO2 Pipeline and Storage project. Ultimately the project did not proceed to construction due to insufficient time to complete necessary EPC contract negotiations and commercial financing prior to expiration of federal co-funding, which triggered a DOE decision to closeout its participation in the project. Through the work that was completed, valuable technical, commercial, and programmatic lessons were learned. This project has significantly advanced the development of near-zero emission technology and will

  11. The Effects of Oxy-firing Conditions on Gas-phase Mercury Oxidation by Chlorine and Bromine

    Buitrago, Paula; Silcox, Geoffrey

    2010-06-30

    Bench-scale experiments were conducted in a quartz-lined, natural gas-fired reactor with the combustion air replaced with a blend of 27 mole percent oxygen, with the balance carbon dioxide. Quench rates of 210 and 440 K/s were tested. In the absence of sulfur dioxide, the oxy-firing environment caused a remarkable increase in oxidation of mercury by chlorine. At 400 ppm chlorine (as HCl equivalent), air-firing results in roughly 5 percent oxidation. At the same conditions with oxy-firing, oxidation levels are roughly 80 percent. Oxidation levels with bromine at 25 and 50 ppm (as HBr equivalent) ranged from 80 to 95 percent and were roughly the same for oxy- and air-firing conditions. Kinetic calculations of levels of oxidation at air- and oxy-conditions captured the essential features of the experimental results but have not revealed a mechanistic basis for the oxidative benefits of oxy-firing conditions. Mixtures of 25 ppm bromine and 100 and 400 ppm chlorine gave more than 90 percent oxidation. At all conditions, the effects of quench rate were not significant. The presence of 500 ppm SO2 caused a dramatic decline in the levels of oxidation at all oxy-fired conditions examined. This effect suggests that SO2 may be preventing oxidation in the gas phase or preventing oxidation in the wetconditioning system that was used in quantifying oxidized and elemental mercury concentrations. Similar effects of SO2 have been noted with air-firing. The addition of sodium thiosulfate to the hydroxide impingers that are part of wet conditioning systems may prevent liquid-phase oxidation from occurring.

  12. Clinical application of OxyContin hydrochloride controlled release tablets in treatment of pain suffered from advanced cancer

    Wenwu Wang; Xuenong OuYang; Zongyang Yu; Zhangshu Chen

    2012-01-01

    Objective: The aim of this study was to evaluate the efficacy and adverse reactions of OxyContin hydrochloride controlled release tablets in the treatment of moderate or severe pain in patients with terminal cancer and to observe any improvement on the cancer patients' quality of life. Methods: Sixty-eight patients with moderate or severe cancer pain were treated with OxyContin hydrochloride controlled release tablets. The initial dose was 5 mg/12h, or 1/2 that of the standard morphine regimen. During the course of treatment, the dosage was adjusted according to the patients' condition until the pain completely disappeared or nearly did so. Each patient received a treatment for at least 15 days. At the same time, adverse reactions, the quality of life and scores for the intensity of pain were observed and recorded [1]. Results: The final titrated dosage of OxyContin was as follows: the patients in 30 cases (44.1%) received a dosage of ≤ 30 mg/d, those in 16 cases (23.5%) received a dosage of 31 to 60 mg/d, those in 18 cases (26.5%) received a dosage of 61 to 120 mg/d and those in 4 cases (5.9%) received a dosage of ≥ 120 mg/d. The overall rate of relief from pain was 95.6%, among which the rates of excellent, effective and moderate relief were respectively 39.7%, 48.5% and 7.4%. OxyContin had mild adverse reactions and patients' quality of life was markedly improved. Conclusion: OxyContin is effective in treatment of moderate and severe cancer pain. The adverse reactions of OxyContin are mild, and the drug can significantly improve the quality of life of patients with cancer pain.

  13. Experiences in sulphur capture in a 30 MWth Circulating Fluidized Bed boiler under oxy-combustion conditions

    CO2 and SO2 from fossil fuel combustion are contributors to greenhouse effect and acid rain respectively. Oxy-combustion technology produces a highly concentrated CO2 stream almost ready for capture. Circulating Fluidized Bed (CFB) boiler technology allows in-situ injection of calcium-based sorbents for efficient SO2 capture. CIUDEN's 30 MWth CFB boiler, supplied by Foster Wheeler and located at the Technology Development Centre for CO2 Capture and Transport (es.CO2) in Spain, is the first of its kind for executing test runs at large pilot scale under both air-combustion and oxy-combustion conditions. In this work, SO2 emissions under different scenarios have been evaluated. Variables such as limestone composition, Ca/S molar ratio and bed temperature among others have been considered along different test runs in both air-combustion and oxy-combustion conditions to analyse its influence on SO2 abatement. Fly and bottom ash, together with flue gas analysis have been carried-out. Desulphurization performance tests results are presented. - Highlights: •Sulphur capture efficiency (%) was higher in oxy-combustion compared to air-combustion in a 30 MW thermal CFB boiler using anthracite and limestone as sulphur sorbent. •For a Ca/S molar ratio higher than 2.6 there was barely any improvement on sulphur capture efficiency for both air-combustion and oxy-combustion conditions in a 30 MW thermal CFB boiler using anthracite and limestone as sulphur sorbent. •Optimum temperature for sulphur capture at a fixed Ca/S molar ratio is around 880–890 °C under oxy-combustion conditions and for anthracite coal with limestone as sorbent in a 30 MW thermal CFB boiler

  14. Optimization and control for CO2 compression and purification unit in oxy-combustion power plants

    High CO2 purity products can be obtained from oxy-combustion power plants through a CO2 CPU (compression and purification unit) based on phase separation method. To ensure that CPU (with double flash separators) can be operated under optimal conditions, this paper focuses on single variable analysis, multi-variable optimization, dynamic simulation and control system design for CPU in oxy-combustion power plants. It is found that optimal operating conditions are 30 bar, 30.42 °C, −24.64 °C, and −55 °C for multi-stage CO2 compressor discharge pressure, flue gas temperature after compression, first flash separator temperature, and second flash separator temperature, respectively. The designed double temperature control structure based on a systematic top-down analysis and bottom-up design method is more suitable than the single temperature control structure under different operating scenarios (load change and flue gas composition ramp change). To bear operating disturbances, operating strategies like elevating temperature, manipulating valves and adjusting setpoints are proposed. Influence of SOx would be more obvious than that of NOx, whilst the kij mixing parameters in Peng–Robinson property method affects little on process optimization and control system design. Comprehensive dynamic model with specified control system provides possibility to integrate CPU with full-train oxy-combustion power plants. - Highlights: • Dynamic model of CO2 compression and purification unit is established. • Double temperature control system for compression and purification unit is designed. • The designed control system is tested successfully under load change and disturbance. • Comprehensive dynamic behavior for key operating parameters is obtained. • Alternative control structure is also investigated and compared

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

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

    2009-07-01

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

  16. The effects of copper oxy chloride waste contamination on selected soil biochemical properties at disposal site

    A study was carried out at a sanitary waste disposal site for Kutsaga Tobacco Research Station, Zimbabwe, which uses large amounts of copper oxy chloride for sterilization of recycled float trays in flooded bench tobacco seedling production systems. Soil samples randomly collected from six stream bank zones (bands up the valley slope) varying in their distance ranges from the centre of both the wastewater-free and wastewater-affected paths [0-5 m (B1); 6-10 m (B2); 11-15 m (B3); 16-20 m (B4); 21-25 m (B5) and 26-30 m (B6)] in two sample depths (0-15; 15-30 cm) were analysed for metal copper, organic matter contents, and soil pH and subjected to agarized incubation for microbial counts. Results suggest that the repeated disposals of copper oxy chloride waste from tobacco float tray sanitation sinks into a creek amplify metal copper loads in the soil by 500 fold. The greatest concentrations of copper in both the topsoil and upper subsoil were recorded in the B3, B4 and B5 stream bank zones of the wastewater path. The concentration of copper was significantly lower in the middle of the waste-affected creek than that in the stream bank zones. This trend in the copper concentration coincided with the lowest acidity of the soil. Overloading the soil with copper, surprisingly, enhances the content of soil organic matter. The repeated release of copper oxy chloride waste into a stream causes an accelerated build-up of metal copper and soil acidity in the stream bank on-site while contamination is translocated to either underground water reserve or surface stream water flow in the middle of the wastewater path

  17. Oxy-fuel combustion systems for pollution free coal fired power generation

    Ochs, Thomas L.; Oryshchyn, Danylo B.; Gross, Dietrich (Jupiter Oxygen Corp.); Patrick, Brian (Jupiter Oxygen Corp.); Gross, Alex (Jupiter Oxygen Corp.); Dogan, Cindy; Summers, Cathy A.; Simmons, William (CoalTeck LLC); Schoenfeld, Mark (Jupiter Oxygen Corp.)

    2004-01-01

    Jupiter Oxygen's patented oxy-fuel combustion systems1 are capable of economically generating power from coal with ultra-low emissions and increased boiler efficiency. Jupiter's system uses pure oxygen as the combustion agent, excluding air and thus nitrogen, concentrating CO2 and pollutants for efficient capture with near zero NOx production, reducing exhaust mass flow, and increasing radiant heat transfer. Flue-gas recirculation rates can be varied to add flexibility to new boiler designs using this technology. Computer modeling and thermal analysis have identified important design considerations in retrofit applications.

  18. Short-term corrosion testing in a burner rig with oxy-fuel and conventional firing

    As part of the European ENCAP project, a test rig has been modified by IVD (Institute of Process - Engineering and Power Plant Technology), Stuttgart, Germany to compare oxy-fuel firing with conventional firing. A broad spectrum of alloys from low alloyed steels to nickel alloys were exposed on a cooled probe in this rig at a metal temperature of 630 C for up to 40 hours with lignite from the Lausitz region as the fuel, and for 26 hours with bituminous coal (Kleinkopje) as fuel. For lignite firing, both exposure with oxy-fuel firing with recirculation of flue gas and conventional firing has been conducted to compare the corrosion attack and deposit composition. Only oxy-fuel tests were conducted with the bituminous coal. For the lignite fuel, the deposit composition from oxy-fuel and conventional firing was similar, and consisted of calcium sulphate (anhydrite) and iron oxide (hematite). The corrosion attack for the different alloys was also similar for both types of combustion. The corrosion attack was oxidation with some sulfidation/sulphation at the oxide-metal interface. In general, the thickness of the corrosion product decreased for the higher alloyed steels. The ferritic steels formed a two layered oxide. The high nickel containing alloy Hastelloy C-2000 showed a surprisingly high corrosion rate with internal attack and an outer nickel oxide. The Kanthal APM and Nimonic 263 alloys had the best oxide with even surface coverage. For the bituminous coal test, there was very little deposit on the specimens, and the deposit was rich in aluminium, silicon, oxygen and iron with lesser amounts of calcium and sulphur. The corrosion attack for the different alloys was similar to that observed for lignite where Kanthal APM had the most protective oxide coverage. Generally the mass gain rates are similar between the different tests for the same material. The main findings from these short term tests are that alumina forming alloys and super austenitic stainless steels

  19. Short-term corrosion testing in a burner rig with oxy-fuel and conventional firing

    Montgomery, M. [Vattenfall Heat Nordic/DTU Mekanik (Denmark); Hjornhede, A. [Vattenfall Power Consultant AB (Sweden); Gerhardt, A. [Institute of Process-Engineering and Power Plant Technology (IVD)/ Vattenfall Research and Development (Germany)

    2009-07-01

    As part of the European ENCAP project, a test rig has been modified by IVD (Institute of Process - Engineering and Power Plant Technology), Stuttgart, Germany to compare oxy-fuel firing with conventional firing. A broad spectrum of alloys from low alloyed steels to nickel alloys were exposed on a cooled probe in this rig at a metal temperature of 630 C for up to 40 hours with lignite from the Lausitz region as the fuel, and for 26 hours with bituminous coal (Kleinkopje) as fuel. For lignite firing, both exposure with oxy-fuel firing with recirculation of flue gas and conventional firing has been conducted to compare the corrosion attack and deposit composition. Only oxy-fuel tests were conducted with the bituminous coal. For the lignite fuel, the deposit composition from oxy-fuel and conventional firing was similar, and consisted of calcium sulphate (anhydrite) and iron oxide (hematite). The corrosion attack for the different alloys was also similar for both types of combustion. The corrosion attack was oxidation with some sulfidation/sulphation at the oxide-metal interface. In general, the thickness of the corrosion product decreased for the higher alloyed steels. The ferritic steels formed a two layered oxide. The high nickel containing alloy Hastelloy C-2000 showed a surprisingly high corrosion rate with internal attack and an outer nickel oxide. The Kanthal APM and Nimonic 263 alloys had the best oxide with even surface coverage. For the bituminous coal test, there was very little deposit on the specimens, and the deposit was rich in aluminium, silicon, oxygen and iron with lesser amounts of calcium and sulphur. The corrosion attack for the different alloys was similar to that observed for lignite where Kanthal APM had the most protective oxide coverage. Generally the mass gain rates are similar between the different tests for the same material. The main findings from these short term tests are that alumina forming alloys and super austenitic stainless steels

  20. Process Simulation of Oxy-combustion CO2 Capture in Cement Plant

    Skinnemoen, Maria Magnussen

    2014-01-01

    The objectives of this master thesis have been to model and simulate oxy-combustion CO2 capture in a cement plant. The model developed is a process simulation of the calcination process with varying degree of air in-leakage, where heat is supplied by combustion in an oxygen rich environment, followed by capture of the CO2. The further gas separation after H2O condensation to achieve the required CO2 quality was evaluated. In addition to the process simulations, a review of literature related ...

  1. Carbon nanotube reinforced aluminum nanocomposite via plasma and high velocity oxy-fuel spray forming.

    Laha, T; Liu, Y; Agarwal, A

    2007-02-01

    Free standing structures of hypereutectic aluminum-23 wt% silicon nanocomposite with multiwalled carbon nanotubes (MWCNT) reinforcement have been successfully fabricated by two different thermal spraying technique viz Plasma Spray Forming (PSF) and High Velocity Oxy-Fuel (HVOF) Spray Forming. Comparative microstructural and mechanical property evaluation of the two thermally spray formed nanocomposites has been carried out. Presence of nanosized grains in the Al-Si alloy matrix and physically intact and undamaged carbon nanotubes were observed in both the nanocomposites. Excellent interfacial bonding between Al alloy matrix and MWCNT was observed. The elastic modulus and hardness of HVOF sprayed nanocomposite is found to be higher than PSF sprayed composites. PMID:17450788

  2. System approach to the analysis of an integrated oxy-fuel combustion power plant

    Ziębik Andrzej; Gładysz Paweł

    2014-01-01

    Oxy-fuel combustion (OFC) belongs to one of the three commonly known clean coal technologies for power generation sector and other industry sectors responsible for CO2 emissions (e.g., steel or cement production). The OFC capture technology is based on using high-purity oxygen in the combustion process instead of atmospheric air. Therefore flue gases have a high concentration of CO2. Due to the limited adiabatic temperature of combustion some part of CO2 must be recycled to the boiler in orde...

  3. Particulate emissions from combustion of biomass in conventional combustion (air) and oxy-combustion conditions

    Ruscio, Amanda Deanne

    Oxy-fuel combustion is a viable technology for new and existing coal-fired power plants, as it facilitates carbon capture and thereby, can reduce carbon dioxide emissions. The use of biomass as an energy source is another popular strategy to reduce carbon dioxide emissions as they are considered nearly carbon dioxide neutral. If the use of biomass is combined with oxy-fuel combustion, negative net emissions of carbon dioxide are possible. This work examined the particulate emissions from combustion of pulverized biomass residues burning in either conventional or oxy-fuel environments. Combustion of three biomasses (olive residue, corn residue, and torrefied pine sawdust) occurred in a laboratory-scale laminar-flow drop tube furnace (DTF) heated to 1400 K. The O2 mole fraction was increased from 20% to 60% in N2 environments while a range of 30% to 60% O2 mole fractions were used in CO2 environments to represent plausible dry oxy-fuel combustion conditions. Submicron particulate matter (PM1) emission yields of all three fuels were typically lower in O2/CO2 environments than in O2/N2 environments. When the oxygen mole fraction was increased, the PM1 yields typically increased. The mass fractions of submicron particulate matter (PM1/PM18) collected from biomass combustion were higher than those of coal combustion. PM 1 constituted approximately 50 wt% of the collected ash particles in PM18 in each environment, whereas the corresponding submicron emissions from coal constituted approximately 20 wt%. Changing the background gas had little effect on the chemical composition of the PM1 particles. Unlike the submicron particles collected from coal which contained high amounts of silicon and aluminum, high amounts of alkalis (potassium, calcium, and sodium) and chlorine were the major elements observed in PM1 from the biomasses. In addition, phosphorous and sulfur also existed in high amounts in PM1 of corn residue. Super-micron particles (PM1-18) yields exhibited no clear

  4. Technical and economic aspects of oxygen separation for oxy-fuel purposes

    Chorowski, Maciej; Gizicki, Wojciech

    2015-03-01

    Oxy combustion is the most promising technology for carbon dioxide, originated from thermal power plants, capture and storage. The oxygen in sufficient quantities can be separated from air in cryogenic installations. Even the state-of-art air separation units are characterized by high energy demands decreasing net efficiency of thermal power plant by at least 7%. This efficiency decrease can be mitigated by the use of waste nitrogen, e.g., as the medium for lignite drying. It is also possible to store energy in liquefied gases and recover it by liquid pressurization, warm-up to ambient temperature and expansion. Exergetic efficiency of the proposed energy accumulator may reach 85%.

  5. Characterization of Oxy-combustion Impacts in Existing Coal-fired Boilers

    Adams, Bradley R. [Univ. of Utah, Salt Lake City, UT (United States); Fry, Andrew R. [Univ. of Utah, Salt Lake City, UT (United States); Senior, Constance L. [Univ. of Utah, Salt Lake City, UT (United States); Shim, Hong Shig [Univ. of Utah, Salt Lake City, UT (United States); Otten, Brydger Van [Univ. of Utah, Salt Lake City, UT (United States); Wendt, Jost [Univ. of Utah, Salt Lake City, UT (United States); Shaddix, Christopher [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Tree, Dale [Brigham Young Univ., Provo, UT (United States)

    2010-06-01

    This report summarizes Year 2 results of a research program designed to use multi-scale experimental studies and fundamental theoretical models to characterize and predict the impacts of retrofit of existing coal-fired utility boilers for oxy-combustion. Year 2 focused extensively on obtaining experimental data from the bench-scale, lab-scale and pilot-scale reactors. These data will be used to refine and validate submodels to be implemented in CFD simulations of full-scale boiler retrofits. Program tasks are on schedule for Year 3 completion. Both Year 2 milestones were completed on schedule and within budget.

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

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

    2011-01-01

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

  7. Oxy-functionalization of nucleophilic rhenium(I) metal carbon bonds catalyzed by selenium(IV)

    Tenn, William J., III; Conley, Brian L.; Hovelmann, Claas H.; Ahlquist, Marten; Nielsen, Robert J.; Ess, Daniel H.; Oxgaard, Jonas; Bischof, Steven M.; Goddard, William A.; Periana, Roy A.

    2009-01-01

    We report that SeO_2 catalyzes the facile oxy-functionalization of (CO)_5Re(I)-Me^(δ−) with IO_4− to generate methanol. Mechanistic studies and DFT calculations reveal that catalysis involves methyl group transfer from Re to the electrophilic Se center followed by oxidation and subsequent reductive functionalization of the resulting CH_3Se(VI) species. Furthermore, (CO)_3Re(I)(Bpy)-R (R = ethyl, n-propyl, and aryl) complexes show analogous transfer to SeO_2 to generate the primary alcohols. T...

  8. Investigation on Flame Characteristics and Burner Operability Issues of Oxy-Fuel Combustion

    Choudhuri, Ahsan [Univ. Of Texas, El Paso, TX (United States)

    2013-09-30

    Oxy-fuel combustion has been used previously in a wide range of industrial applications. Oxy- combustion is carried out by burning a hydrocarbon fuel with oxygen instead of air. Flames burning in this configuration achieve higher flame temperatures which present opportunities for significant efficiency improvements and direct capture of CO2 from the exhaust stream. In an effort to better understand and characterize the fundamental flame characteristics of oxy-fuel combustion this research presents the experimental measurements of flame stability of various oxyfuel flames. Effects of H2 concentration, fuel composition, exhaust gas recirculation ratio, firing inputs, and burner diameters on the flame stability of these fuels are discussed. Effects of exhaust gas recirculation i.e. CO2 and H2O (steam) acting as diluents on burner operability are also presented. The roles of firing input on flame stability are then analyzed. For this study it was observed that many oxy-flames did not stabilize without exhaust gas recirculation due to their higher burning velocities. In addition, the stability regime of all compositions was observed to decrease as the burner diameter increased. A flashback model is also presented, using the critical velocity gradient gF) values for CH4-O2-CO2 flames. The second part of the study focuses on the experimental measurements of the flow field characteristics of premixed CH4/21%O2/79%N2 and CH4/38%O2/72%CO2 mixtures at constant firing input of 7.5 kW, constant, equivalence ratio of 0.8, constant swirl number of 0.92 and constant Reynolds Numbers. These measurements were taken in a swirl stabilized combustor at atmospheric pressure. The flow field visualization using Particle Imaging Velocimetry (PIV) technique is implemented to make a better understanding of the turbulence characteristics of

  9. Aerosols from oxy-acetylene gas cutting operations on metal plates: a laboratory study

    The decommissioning of radioactively contaminated sites has the potential for creating radioactive and other potentially toxic aerosols. Laboratory studies characterized aerosols from oxy-acetylene cutting of carbon steel and stainless steel, and steel coated with stable Cs, Cd and Sr to simulate fission product contamination. Aerosol characteristics were studied with an electrical aerosol analyzer, a scanning electron microscope, filters, cascade impactors and an HCl impinger trap. Quantification of aerosolized products was by atomic absorption spectroscopy. In general, gas cutting operations produced a multicomponent, multimodal, respirable-sized aerosol

  10. 2-(Acet­oxy­meth­yl)benzoic acid

    Gainsford, Graeme J.; Schwörer, Ralf

    2013-01-01

    The title compound, C10H10O4, crystallizes with the well-known carb­oxy­lic acid dimer-forming R 2 2(8) hydrogen-bond motif. Chains approximately parallel to (-1-12) are then built through C(methyl­ene,phen­yl)–H⋯O(carbon­yl) inter­actions [C(6) and C(8) motifs] with one (meth­yl)C—H⋯π inter­action providing inter­planar binding. The weakness of the latter inter­action is consistent with the difficulty experienced in obtaining suitable single crystals.

  11. Experimental studies on heat transfer of oxy-coal combustion in a large-scale laboratory furnace

    A number of issues arise in the transition from air-firing to oxy-firing. In situations where the furnace should be retrofitted for oxy-firing, a similar heat transfer performance is crucial for operation of power plants. A survey of recent literature turned up very little detailed research on the characterization of pulverized oxy-coal flames generated by staged feed-gas burners and the impacts of burner settings on heat transfer performance. A large number of studies applied either O2 fraction upstream of the burner or recycle ratio as main parameter to characterize oxy-fired conditions. For this reason, this study applies other characteristic parameters, as for example swirl number and feed gas flow ratio between the burner registers, rather than only O2 concentration for operation of the test facility. Experiments were conducted in a test facility with a rated capacity of 0.40 MWth fired by an industry-type burner. A theoretical study was also carried out to calculate combustion parameters, e.g., adiabatic flame temperature, in order to define burner settings and assess the experimental results. The burner was set to operate at three levels of secondary swirl number (1.15, 1.65, and 2.05), while part of the feed gas was divided between the secondary and tertiary registers using flow ratios between 0.40 and 2.00. For completeness, three levels of O2 fraction upstream of the burner (29, 31, and 33 vol% O2) were also tested under oxy-fired conditions. Measurements of peak flame temperature, absorbed heat flux at the water-cooled walls, and total radiative heat flux were performed and applied besides heat balance calculations to evaluate heat transfer performance. Experimental data indicated the feed gas distribution among the burner registers control the heat transfer in the furnace in parallel with the swirl strength of the secondary flow for both air-fired and oxy-fired conditions. Even though lower flame temperatures were obtained in oxy-firing, the results

  12. Oxy-fuel combustion boiler for CO2 capturing: 50 kW-class model test and numerical simulation

    A novel oxy-fuel burner was devised and integrated into a 50 kW-class furnace-type boiler system. A series of experiments was conducted to verify its feasibility for industrial applications. Additionally, numerical simulations were performed and the results validated against experimental data on the detailed physics inside the conventional-design combustion chamber. The oxy-fuel burner, with the help of gas radiation, could effectively heat the combustion chamber. The composition of the exhaust gas revealed that the sealing of the system is crucial to the achievement of high CO2 concentrations and low NOx emissions

  13. Microsynthesis of a novel herbicide, propyl 4-[2-[(4,6-dimethoxy-2-pyrimidinyl)oxy] benzylamino] benzoate

    ZJ273, propyl 4-[2-[(4,6-dimethoxy-2-pyrimidinyl)oxy] benzylamino] benzoate, is a novel herbicide. The microsynthetic method of the compound was developed from 4,6-dimethoxy-2-pyrimidine, propyl (4-benzylamino) benzoate and phenol, and then purified by preparative-HPLC. The yield of end product was 53%. Its chemical structure was characterized by means of 1H-NMR, MS, UV, and its chemical purity was determined to be exceed 98% by HPLC. The microsynthetic method of propyl 4-[2-[(4,6-dimethoxy-2-pyrimidinyl)oxy] benzylamino] benzoate developed sets up a basis to synthesize the radioisotopic labeled target compound. (authors)

  14. Crystal structure of benzene-1,3,5-tri-carb-oxy-lic acid-4-pyridone (1/3).

    Staun, Selena L; Oliver, Allen G

    2015-11-01

    Slow co-crystallization of a solution of benzene-1,3,5-tri-carb-oxy-lic acid with a large excess of 4-hy-droxy-pyridine produces an inter-penetrating, three-dimensional, hydrogen-bonded framework consisting of three 4-pyridone and one benzene-1,3,5-tri-carb-oxy-lic acid mol-ecules, C9H6O6·3C5H5NO. This structure represents an ortho-rhom-bic polymorph of the previously reported C-centered, monoclinic structure [Campos-Gaxiola et al. (2014 ▸). Acta Cryst. E70, o453-o454]. PMID:26594492

  15. DETERMINATION OF THE KINETIC PARAMETERS OF OXY-FUEL COMBUSTION OF COAL WITH A HIGH ASH CONTENT

    K. G. P. Nunes; N. R. Marcílio

    2015-01-01

    Abstract The aim of this study was to determine the kinetic parameters of the oxy-fuel combustion of char from a Brazilian bituminous coal with a high ash content. The char, with a particle diameter of 715 μm, was prepared in a N2 atmosphere at 1173 K. The oxy-fuel combustion assays were performed using a thermobalance at different temperatures and O2/CO2 gas mixtures of different concentrations. According to the unreacted core model, the process is determined by chemical reaction at low temp...

  16. Thermodynamic evaluation of supercritical oxy-type power plant with high-temperature three-end membrane for air separation

    Kotowicz Janusz; Balicki Adrian; Michalski Sebastian

    2014-01-01

    Among the technologies which allow to reduce greenhouse gas emissions, mainly of carbon dioxide, special attention deserves the idea of ‘zero-emission’ technology based on boilers working in oxy-combustion technology. In the paper a thermodynamic analysis of supercritical power plant fed by lignite was made. Power plant consists of: 600 MW steam power unit with live steam parameters of 650 °C/30 MPa and reheated steam parameters of 670 °C/6 MPa; circulating fluidized bed boiler working in oxy...

  17. Two-dimensional hydrogen-bonded polymers in the crystal structures of the ammonium salts of phen­oxy­acetic acid, (4-fluoro­phen­oxy)acetic acid and (4-chloro-2-methyl­phen­oxy)acetic acid

    Graham Smith

    2014-01-01

    The structures of the ammonium salts of phen­oxy­acetic acid, NH4 +·C8H6O3 −, (I), (4-fluoro­phen­oxy)acetic acid, NH4 +·C8H5FO3 −, (II), and the herbicidally active (4-chloro-2-methyl­phen­oxy)acetic acid (MCPA), NH4 +·C9H8ClO3 −·0.5H2O, (III) have been determined. All have two-dimensional layered structures based on inter-species ammonium N—H⋯O hydrogen-bonding associations, which give core substructures consisting primarily of conjoined cyclic motifs. The crystals of (I) and (II) are isomo...

  18. Effect of flue gas recirculation during oxy-fuel combustion in a rotary cement kiln

    The effect of Flue Gas Recirculation (FGR) during Oxy-Fuel Combustion in a Rotary Cement Kiln was analyzed by using a CFD model applied to coal combustion process. The CFD model is based on 3D-balance equations for mass, species, energy and momentum. Turbulence and radiation model coupled to a chemical kinetic mechanism for pyrolysis processes, gas–solid and gas–gas reactions was included to predicts species and flame temperature distribution, as well as convective and radiation energy fluxes. The model was used to study coal combustion with air and with oxygen for FGR between 30 and 85% as controller parameter for temperature in the process. Flame length effect and heat transfer by convection and radiation to the clinkering process for several recirculation ratios was studied. Theoretical studies predicted a located increase of energy flux and a reduction in flame length with respect to the traditional system which is based on air combustion. The impact of FGR on the oxy-fuel combustion process and different energy scenarios in cement kilns to increase energy efficiency and clinker production were studied and evaluated. Simulation results were in close agreement with experimental data, where the maximum deviation was 7%

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

    Hanna Wollocko

    2011-12-01

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

  20. Analysis of oxy-fuel combustion power cycle utilizing a pressurized coal combustor

    Growing concerns over greenhouse gas emissions have driven extensive research into new power generation cycles that enable carbon dioxide capture and sequestration. In this regard, oxy-fuel combustion is a promising new technology in which fuels are burned in an environment of oxygen and recycled combustion gases. In this paper, an oxy-fuel combustion power cycle that utilizes a pressurized coal combustor is analyzed. We show that this approach recovers more thermal energy from the flue gases because the elevated flue gas pressure raises the dew point and the available latent enthalpy in the flue gases. The high-pressure water-condensing flue gas thermal energy recovery system reduces steam bleeding which is typically used in conventional steam cycles and enables the cycle to achieve higher efficiency. The pressurized combustion process provides the purification and compression unit with a concentrated carbon dioxide stream. For the purpose of our analysis, a flue gas purification and compression process including de-SOx, de-NOx, and low temperature flash unit is examined. We compare a case in which the combustor operates at 1.1 bars with a base case in which the combustor operates at 10 bars. Results show nearly 3% point increase in the net efficiency for the latter case.

  1. Nano sized bismuth oxy chloride by metal organic chemical vapour deposition

    Jagdale, Pravin, E-mail: pravin.jagdale@polito.it [Department of Applied Science and Technology (DISAT), Politecnico di Torino, 10129 (Italy); Castellino, Micaela [Center for Space Human Robotics, Istituto Italiano di Tecnologia, Corso Trento 21, 10129 Torino (Italy); Marrec, Françoise [Laboratory of Condensed Matter Physics, University of Picardie Jules Verne (UPJV), Amiens 80039 (France); Rodil, Sandra E. [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexicom (UNAM), Mexico D.F. 04510 (Mexico); Tagliaferro, Alberto [Department of Applied Science and Technology (DISAT), Politecnico di Torino, 10129 (Italy)

    2014-06-01

    Metal organic chemical vapour deposition (MOCVD) method was used to prepare thin films of bismuth based nano particles starting from bismuth salts. Nano sized bismuth oxy chloride (BiOCl) crystals were synthesized from solution containing bismuth chloride (BiCl{sub 3}) in acetone (CH{sub 3}-CO-CH{sub 3}). Self-assembly of nano sized BiOCl crystals were observed on the surface of silicon, fused silica, copper, carbon nanotubes and aluminium substrates. Various synthesis parameters and their significant impact onto the formation of self-assembled nano-crystalline BiOCl were investigated. BiOCl nano particles were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy and Micro-Raman spectroscopy. These analyses confirm that bismuth nanometer-sized crystal structures showing a single tetragonal phase were indeed bismuth oxy chloride (BiOCl) square platelets 18–250 nm thick and a few micrometres wide.

  2. Oxy-fuel combustion characteristics and kinetics of microalgae Chlorella vulgaris by thermogravimetric analysis.

    Chen, Chunxiang; Lu, Ziguang; Ma, Xiaoqian; Long, Jun; Peng, Yuning; Hu, Likun; Lu, Quan

    2013-09-01

    Oxy-fuel or O2/CO2 combustion technology was used to investigate the combustion of Chlorella vulgaris by thermogravimetric analysis (TGA). Oxy-fuel combustion occurs in an O2/CO2 atmosphere instead of an O2/N2 atmosphere and offers an alternative method of C. vulgaris preparation for biofuels processing. Our results show that three stages were observed during C. vulgaris combustion and the main combustion process occurred at the second stage. Compared with a 20%O2/80%N2 atmosphere, the mass loss rate at the DTG peaks (Rp) and the average reaction rate (Rv) in a 20%O2/80%CO2 atmosphere was lower, while the ignition temperature (TI) was higher. As oxygen concentration increases in an O2/CO2 atmosphere, Rp, Rv and the apparent activation energy (E) increases, while TI, the final temperature detected as mass stabilization (Tf) and the residue mass (Mr) decreases; As the heating rate (β) increases, TI, Tf and Rp increase, while Mr decreases. PMID:23890976

  3. The Effect of Oxygen Staging on Nitrogen Conversion in Oxy-Fuel CFB Environment

    Jankowska Sylwia

    2014-12-01

    Full Text Available This paper presents a study on nitrogen conversion in oxy-fuel coal combustion in a pilot scale CFB 0.1 MWth facility. The paper is focused on fuel-N behaviour in the combustion chamber when the combustion process is accomplished under oxy-fuel CFB conditions. The analysis is based on infurnace sampling of flue gas and calculations of the conversion ratios of fuel-nitrogen (fuel-N to NO, NO2, N2O, NH3 and HCN. For the tests, O2/CO2 mixtures with the oxygen content of 21 vol.% (primary gas and with the oxygen content varied from 21 to 35 vol.% (secondary gas, were used as the fluidising gas. Measurements were carried out in 4 control points located along the combustion chamber: 0.43 m, 1.45 m, 2.50 m and 4.88 m. Results presented below indicate that an increased oxygen concentration in the higher part of the combustion chamber has strong influence on the behaviour of fuel based nitrogen compounds.

  4. Life Cycle Assessment of New Oxy-Fuels from Biodiesel-Derived Glycerol

    Francesco Asdrubali

    2015-02-01

    Full Text Available Biodiesel is obtained by the process of transesterification of vegetable oils and animal fats and crude glycerol is the main by-product of the biodiesel manufacturing chain. As a result glycerol production has rapidly increased in the last decades. This work focuses on the development and the validation of a process to convert biodiesel-derived glycerol into a fuel for internal combustion engines. In order to obtain a higher conversion efficiency it was necessary to convert crude glycerol to tert-butyl ethers by means of an etherification process that was carried out in the laboratory. Then the obtained glycol-ethers mixture (GEM was blended with a commercial diesel fuel to improve its thermal efficiency. In this paper a life cycle analysis for these GEM/diesel blends was carried out using a Life Cycle Assessment (LCA methodology, in order to evaluate the environmental impacts of these new oxy-fuels; from GEM production to GEM use as an additive for diesel fuel. The LCA results highlight that the use of these new oxy-fuels in diesel engines can lead to an effective reduction in terms of greenhouse gases emissions throughout the entire life cycle.

  5. System approach to the analysis of an integrated oxy-fuel combustion power plant

    Ziębik, Andrzej; Gładysz, Paweł

    2014-09-01

    Oxy-fuel combustion (OFC) belongs to one of the three commonly known clean coal technologies for power generation sector and other industry sectors responsible for CO2 emissions (e.g., steel or cement production). The OFC capture technology is based on using high-purity oxygen in the combustion process instead of atmospheric air. Therefore flue gases have a high concentration of CO2. Due to the limited adiabatic temperature of combustion some part of CO2 must be recycled to the boiler in order to maintain a proper flame temperature. An integrated oxy-fuel combustion power plant constitutes a system consisting of the following technological modules: boiler, steam cycle, air separation unit, cooling water and water treatment system, flue gas quality control system and CO2 processing unit. Due to the interconnections between technological modules, energy, exergy and ecological analyses require a system approach. The paper present the system approach based on the `input-output' method to the analysis of the: direct energy and material consumption, cumulative energy and exergy consumption, system (local and cumulative) exergy losses, and thermoecological cost. Other measures like cumulative degree of perfection or index of sustainable development are also proposed. The paper presents a complex example of the system analysis (from direct energy consumption to thermoecological cost) of an advanced integrated OFC power plant.

  6. System approach to the analysis of an integrated oxy-fuel combustion power plant

    Ziębik Andrzej

    2014-09-01

    Full Text Available Oxy-fuel combustion (OFC belongs to one of the three commonly known clean coal technologies for power generation sector and other industry sectors responsible for CO2 emissions (e.g., steel or cement production. The OFC capture technology is based on using high-purity oxygen in the combustion process instead of atmospheric air. Therefore flue gases have a high concentration of CO2. Due to the limited adiabatic temperature of combustion some part of CO2 must be recycled to the boiler in order to maintain a proper flame temperature. An integrated oxy-fuel combustion power plant constitutes a system consisting of the following technological modules: boiler, steam cycle, air separation unit, cooling water and water treatment system, flue gas quality control system and CO2 processing unit. Due to the interconnections between technological modules, energy, exergy and ecological analyses require a system approach. The paper present the system approach based on the ‘input-output’ method to the analysis of the: direct energy and material consumption, cumulative energy and exergy consumption, system (local and cumulative exergy losses, and thermoecological cost. Other measures like cumulative degree of perfection or index of sustainable development are also proposed. The paper presents a complex example of the system analysis (from direct energy consumption to thermoecological cost of an advanced integrated OFC power plant.

  7. Evaluation of solution methods for radiative heat transfer in gaseous oxy-fuel combustion environments

    The exact solution to radiative heat transfer in combusting flows is not possible analytically due to the complex nature of the integro-differential radiative transfer equation (RTE). Many different approximate solution methods for the solution of the RTE in multi-dimensional problems are available. In this paper, two of the principal methods, the spherical harmonics (P1) and the discrete ordinates method (DOM) are used to calculate radiation. The radiative properties of the gases are calculated using a non-gray gas full spectrum k-distribution method and a gray method. Analysis of the effects of numerical quadrature in the DOM and its effect on computation time is performed. Results of different radiative property methods are compared with benchmark statistical narrow band (SNB) data for both cases that simulate air combustion and oxy-fuel combustion. For both cases, results of the non-gray full spectrum k-distribution method are in good agreement with the SNB data. In the case of oxy-fuel simulations with high partial pressures of carbon dioxide, use of gray method for the radiative properties may cause errors and should be avoided.

  8. Effect of biomass blending on coal ignition and burnout during oxy-fuel combustion

    B. Arias; C. Pevida; F. Rubiera; J.J. Pis [Instituto Nacional del Carbon, CSIC, Oviedo (Spain)

    2008-09-15

    Oxy-fuel combustion is a GHG abatement technology in which coal is burned using a mixture of oxygen and recycled flue gas, to obtain a rich stream of CO{sub 2} ready for sequestration. An entrained flow reactor was used in this work to study the ignition and burnout of coals and blends with biomass under oxy-fuel conditions. Mixtures of CO{sub 2}/O{sub 2} of different concentrations were used and compared with air as reference. A worsening of the ignition temperature was detected in CO{sub 2}/O{sub 2} mixtures when the oxygen concentration was the same as that of the air. However, at an oxygen concentration of 30% or higher, an improvement in ignition was observed. The blending of biomass clearly improves the ignition properties of coal in air. The burnout of coals and blends with a mixture of 79%CO{sub 2}-21%O{sub 2} is lower than in air, but an improvement is achieved when the oxygen concentration is 30 or 35%. The results of this work indicate that coal burnout can be improved by blending biomass in CO{sub 2}/O{sub 2} mixtures. 26 refs., 7 figs., 1 tab.

  9. Characteristics modeling for supercritical circulating fluidized bed boiler working in oxy-combustion technology

    Balicki Adrian

    2014-06-01

    Full Text Available Among the technologies which allow to reduce greenhouse gas emission, mainly carbon dioxide, special attention deserves the idea of ‘zeroemission’ technology based on boilers working in oxy-combustion technology. In the paper the results of analyses of the influence of changing two quantities, namely oxygen share in oxidant produced in the air separation unit, and oxygen share in oxidant supplied to the furnace chamber on the selected characteristics of a steam boiler including the degree of exhaust gas recirculation, boiler efficiency and adiabatic flame temperature, was examined. Due to the possibility of the integration of boiler model with carbon dioxide capture, separation and storage installation, the subject of the analysis was also to determine composition of the flue gas at the outlet of a moisture condensation installation. Required calculations were made using a model of a supercritical circulating fluidized bed boiler working in oxy-combustion technology, which was built in a commercial software and in-house codes.

  10. Adsorption of Oxy-Anions in the Teaching Laboratory: An Experiment to Study a Fundamental Environmental Engineering Problem

    D'Arcy, Mitch; Bullough, Florence; Moffat, Chris; Borgomeo, Edoardo; Teh, Micheal; Vilar, Ramon; Weiss, Dominik J.

    2014-01-01

    Synthesizing and testing bicomposite adsorbents for the removal of environmentally problematic oxy-anions is high on the agenda of research-led universities. Here we present a laboratory module successfully developed at Imperial College London that introduces the advanced undergraduate student in engineering (chemical, civil, earth) and science…

  11. Hyperfine interactions in soybean and lupin oxy-leghemoglobins studied using Mössbauer spectroscopy with a high velocity resolution

    Kumar, A. [University of Delhi South Campus, Department of Biochemistry (India); Alenkina, I. V. [Ural Federal University, Department of Physical Techniques and Devices for Quality Control, Institute of Physics and Technology (Russian Federation); Zakharova, A. P. [Ural Federal University, Department of Experimental Physics, Institute of Physics and Technology (Russian Federation); Oshtrakh, M. I., E-mail: oshtrakh@gmail.com; Semionkin, V. A. [Ural Federal University, Department of Physical Techniques and Devices for Quality Control, Institute of Physics and Technology (Russian Federation)

    2015-04-15

    A comparative study of monomeric soybean and lupin leghemoglobins in the oxy-form was carried out using Mössbauer spectroscopy with a high velocity resolution at 90 K. The {sup 57}Fe hyperfine parameters of measured spectra were evaluated and compared with possible structural differences in the heme Fe(II)–O {sub 2} bond.

  12. Semi-automated structural characterisation of high velocity oxy fuel thermally sprayed WC-Co based coatings

    The application of an automated procedure for the rapid assessment of selected area electron diffraction patterns is described. Comparison with complementary EDX spectra has enabled the thermal decomposition reactions within high velocity oxy-fuel thermally sprayed WC-Co coatings to be investigated.

  13. Hyperfine interactions in soybean and lupin oxy-leghemoglobins studied using Mössbauer spectroscopy with a high velocity resolution

    A comparative study of monomeric soybean and lupin leghemoglobins in the oxy-form was carried out using Mössbauer spectroscopy with a high velocity resolution at 90 K. The 57Fe hyperfine parameters of measured spectra were evaluated and compared with possible structural differences in the heme Fe(II)–O 2 bond

  14. Semi-automated structural characterisation of high velocity oxy fuel thermally sprayed WC-Co based coatings

    Fay, M W [Nottingham Nanotechnology and Nanoscience Centre, University of Nottingham, Nottingham, NG7 2RD (United Kingdom); Han, Y; McCartney, G; Brown, P D [School of Mechanical, Materials and Manufacturing Engineering, University of Nottingham, Nottingham, NG7 2RD (United Kingdom); Korpiola, K [Helsinki University of Technology (Finland)], E-mail: michael.fay@nottingham.ac.uk

    2008-08-15

    The application of an automated procedure for the rapid assessment of selected area electron diffraction patterns is described. Comparison with complementary EDX spectra has enabled the thermal decomposition reactions within high velocity oxy-fuel thermally sprayed WC-Co coatings to be investigated.

  15. Semi-automated structural characterisation of high velocity oxy fuel thermally sprayed WC-Co based coatings

    Fay, M. W.; Han, Y.; McCartney, G.; Korpiola, K.; Brown, P. D.

    2008-08-01

    The application of an automated procedure for the rapid assessment of selected area electron diffraction patterns is described. Comparison with complementary EDX spectra has enabled the thermal decomposition reactions within high velocity oxy-fuel thermally sprayed WC-Co coatings to be investigated.

  16. Characterization of ashes from a 100 kWth pilot-scale circulating fluidized bed with oxy-fuel combustion

    Highlights: → Oxy-fuel combustion was carried out in a 100 kWth circulating fluidized bed. → Coal and petroleum coke are fuels together with limestone added for SO2 capture. → The ashes produced are characterized and compared with air-firing CFBC ash. → The dominant calcium compounds in the ash are CaCO3 and CaSO4 rather than CaO. - Abstract: Oxy-fuel combustion experiments have been carried out on an oxygen-fired 100 kWth mini-circulating fluidized bed combustion (CFBC) facility. Coal and petroleum coke were used as fuel together with different limestones (and fixed Ca:S molar ratios) premixed with the fuel, for in situ SO2 capture. The bed ash (BA) and fly ash (FA) samples produced from this unit were collected and characterized to obtain physical and chemical properties of the ash samples. The characterization methods used included X-ray fluorescence (XRF), X-ray diffraction (XRD), char carbon and free lime analysis, thermogravimetric analysis (TGA), and surface analysis. The main purpose of this work is to characterize the CFBC ashes from oxy-fuel firing to obtain a better understanding of the combustion process, and to identify any significant differences from the ash generated by a conventional air-fired CFBC. The primary difference in the sulfur capture mechanism between atmospheric air-fired and oxy-fuel FBC, at typical FBC temperatures (∼850 oC), is that, in the air-fired case the limestone sorbents calcine, whereas the partial pressure of CO2 in oxy-fuel FBC is high enough to prevent calcination, and hence the sulfation process should mimic that seen in pressurized FBC (PFBC). Here, the char carbon content in the fly ash was much higher than that in the bed ash, and was also high by comparison with ash obtained from conventional commercial air-firing CFBC units. In addition, measurements of the free lime content in the bed and fly ash showed that the unreacted Ca sorbent was present primarily as CaCO3, indicating that sulfur capture in the oxy

  17. Tantalum (oxy)nitrides: Preparation, characterisation and enhancement of photo-Fenton-like degradation of atrazine under visible light

    Highlights: → The photocatalytic activity of TaON for Fe3+ reduction is higher than that of Ta3N5. → Atrazine degradation was accelerated significantly by tantalum (oxy)nitrides sample. → The regenerated catalyst displays considerably stable performance for atrazine degradation. - Abstract: Tantalum (oxy)nitrides were prepared by the nitridation of Ta2O5 and were added to a photo-Fenton-like system to enhance Fe3+ reduction and atrazine degradation under visible light. The samples were characterized by XRD, XPS, DRS and BET analyses. XPS analysis showed that the nitrogen content of the tantalum (oxy)nitride samples increased noticeably with the nitridation temperature and nitridation time but slightly with the flow rate of NH3. XRD results showed Ta2O5 was first converted to TaON and then to Ta3N5 when the nitridation temperature increased. DRS analysis showed that the sample obtained at 800 oC displayed the strongest absorption of visible light. However, the ability of the tantalum (oxy)nitrides to reduce Fe3+ did not increase continuously with the nitrogen content. Sample 7 (700 oC, QNH3=0.3L/min, 6 h) showed the highest level of photocatalytic activity for Fe3+ reduction. This is because the photocatalytic activity of TaON for Fe3+ reduction is higher than that of Ta3N5. And a slight synergetic effect was observed between TaON and Ta3N5. With the addition of sample 7, H2O2 decomposition and atrazine degradation were significantly accelerated in a photo-Fenton-like system under visible light. The regenerated tantalum (oxy)nitrides catalyst displayed considerably stable performance for atrazine degradation.

  18. Impact of oxy-fuel combustion gases on mercury retention in activated carbons from a macroalgae waste: effect of water.

    Lopez-Anton, M A; Ferrera-Lorenzo, N; Fuente, E; Díaz-Somoano, M; Suarez-Ruíz, I; Martínez-Tarazona, M R; Ruiz, B

    2015-04-01

    The aim of this study is to understand the different sorption behaviors of mercury species on activated carbons in the oxy-fuel combustion of coal and the effect of high quantities of water vapor on the retention process. The work evaluates the interactions between the mercury species and a series of activated carbons prepared from a macroalgae waste (algae meal) from the agar-agar industry in oxy-combustion atmospheres, focussing on the role that the high concentration of water in the flue gases plays in mercury retention. Two novel aspects are considered in this work (i) the impact of oxy-combustion gases on the retention of mercury by activated carbons and (ii) the performance of activated carbons prepared from biomass algae wastes for this application. The results obtained at laboratory scale indicate that the effect of the chemical and textural characteristics of the activated carbons on mercury capture is not as important as that of reactive gases, such as the SOx and water vapor present in the flue gas. Mercury retention was found to be much lower in the oxy-combustion atmosphere than in the O2+N2 (12.6% O2) atmosphere. However, the oxidation of elemental mercury (Hg0) to form oxidized mercury (Hg2+) amounted to 60%, resulting in an enhancement of mercury retention in the flue gas desulfurization units and a reduction in the amalgamation of Hg0 in the CO2 compression unit. This result is of considerable importance for the development of technologies based on activated carbon sorbents for mercury control in oxy-combustion processes. PMID:25585865

  19. Characterization of ashes from a 100 kWth pilot-scale circulating fluidized bed with oxy-fuel combustion

    Wu, Y.H.; Wang, C.B.; Tan, Y.W.; Jia, L.F.; Anthony, E.J. [Natural Resources Canada, Ottawa, ON (Canada)

    2011-09-15

    Oxy-fuel combustion experiments have been carried out on an oxygen-fired 100 kW(th) mini-circulating fluidized bed combustion (CFBC) facility. Coal and petroleum coke were used as fuel together with different limestones (and fixed Ca:S molar ratios) premixed with the fuel, for in situ SO{sub 2} capture. The bed ash (BA) and fly ash (FA) samples produced from this unit were collected and characterized to obtain physical and chemical properties of the ash samples. The characterization methods used included X-ray fluorescence (XRF), X-ray diffraction (XRD), char carbon and free lime analysis, thermogravimetric analysis (TGA), and surface analysis. The main purpose of this work is to characterize the CFBC ashes from oxy-fuel firing to obtain a better understanding of the combustion process, and to identify any significant differences from the ash generated by a conventional air-fired CFBC. The primary difference in the sulfur capture mechanism between atmospheric air-fired and oxy-fuel FBC, at typical FBC temperatures (similar to 850{sup o}C), is that, in the air-fired case the limestone sorbents calcine, whereas the partial pressure of CO{sub 2} in oxy-fuel FBC is high enough to prevent calcination, and hence the sulfation process should mimic that seen in pressurized FBC (PFBC). Here, the char carbon content in the fly ash was much higher than that in the bed ash, and was also high by comparison with ash obtained from conventional commercial air-firing CFBC units. In addition, measurements of the free lime content in the bed and fly ash showed that the unreacted Ca sorbent was present primarily as CaCO{sub 3}, indicating that sulfur capture in the oxy-fuel combustor occurred via direct sulfation.

  20. Laminar oxy-fuel diffusion flame supported by an oxygen-permeable-ion-transport membrane

    Hong, Jongsup

    2013-03-01

    A numerical model with detailed gas-phase chemistry and transport was used to predict homogeneous fuel conversion processes and to capture the important features (e.g., the location, temperature, thickness and structure of a flame) of laminar oxy-fuel diffusion flames stabilized on the sweep side of an oxygen permeable ion transport membrane (ITM). We assume that the membrane surface is not catalytic to hydrocarbon or syngas oxidation. It has been demonstrated that an ITM can be used for hydrocarbon conversion with enhanced reaction selectivity such as oxy-fuel combustion for carbon capture technologies and syngas production. Within an ITM unit, the oxidizer flow rate, i.e., the oxygen permeation flux, is not a pre-determined quantity, since it depends on the oxygen partial pressures on the feed and sweep sides and the membrane temperature. Instead, it is influenced by the oxidation reactions that are also dependent on the oxygen permeation rate, the initial conditions of the sweep gas, i.e., the fuel concentration, flow rate and temperature, and the diluent. In oxy-fuel combustion applications, the sweep side is fuel-diluted with CO2, and the entire unit is preheated to achieve a high oxygen permeation flux. This study focuses on the flame structure under these conditions and specifically on the chemical effect of CO2 dilution. Results show that, when the fuel diluent is CO2, a diffusion flame with a lower temperature and a larger thickness is established in the vicinity of the membrane, in comparison with the case in which N2 is used as a diluent. Enhanced OH-driven reactions and suppressed H radical chemistry result in the formation of products with larger CO and H2O and smaller H2 concentrations. Moreover, radical concentrations are reduced due to the high CO2 fraction in the sweep gas. CO2 dilution reduces CH3 formation and slows down the formation of soot precursors, C2H2 and C2H4. The flame location impacts the species diffusion and heat transfer from the

  1. OXI-FLO: an instrument concept for the combined sample preparation and measurement of low energy beta radio-labelled biological samples

    The purpose of the development of the OXI-FLO instrument was to provide an automated system which will produce accurate, reproducible results at a cost which is competitive with current techniques, but which also provides savings in labor. An oxidizer, coupled with a liquid scintillation counter (LSC) has many advantages. The techniques of vial-less LSC was pioneered in this company, during the development of the RSP-β400 Sample Processor, therefore, the technology of transferring and counting a liquid in a stop-flow mode was readily available. The OXI-ONE Sample Oxidizer, also marketed by Radiomatic Instruments, lends itself naturally to the OXI-FLO concept, since the LSC vial is not an integral part of the oxidizer and can be substituted with a different device. These two technologies combined are the basis of the OXI-FLO instrument

  2. A Model for Nitrogen Chemistry in Oxy-Fuel Combustion of Pulverized Coal

    Hashemi, Hamid; Hansen, Stine; Toftegaard, Maja Bøg;

    2011-01-01

    In this work, a model for the nitrogen chemistry in the oxy-fuel combustion of pulverized coal has been developed. The model is a chemical reaction engineering type of model with a detailed reaction mechanism for the gas-phase chemistry, together with a simplified description of the mixing of flows......, heating and devolatilization of particles, and gas–solid reactions. The model is validated by comparison with entrained flow reactor results from the present work and from the literature on pulverized coal combustion in O2/CO2 and air, covering the effects of fuel, mixing conditions, temperature......-fuel combustion and the conventional combustion of pulverized coal can mostly be attributed to the recycling of NO (reburning effect) and to changes in the mixing patterns between fuel and oxygen. For pulverized-fuel combustion at high temperatures, we think that NO is mainly reduced by heterogeneous reactions...

  3. Erosion Resistance of High Velocity Oxy-Fuel WC-Co-Cr Thermal Spray Coatings

    Imeson, Chris

    Thermal spray coatings have been incorporated in oil and gas extraction efforts for many years. Recently, High Velocity Oxy-Fuel (HVOF) has become increasingly incorporated where erosive environments are present. This study investigates the microstructural and mechanical properties of HVOF WC-Co-Cr coatings deposited at SharkSkin Coatings ltd. The deposited coatings exhibited a low porosity with high adhesion strength, hardness, and superior erosion resistance. In this study, a recirculating solid particle erosion testing machine was designed and fabricated to simulate an erosive environment on a laboratory scale. This study was also aimed at improving microstructures and mechanical properties of the coatings by modifying the two coating deposition parameters e.g. standoff and pre-cycle heating. It was determined that pre-spray substrate heating negatively affected the coatings microstructures e.g. porosity, while reducing the stand-off distance positively influenced the coating microstructures and mechanical properties, e.g. erosion resistance.

  4. Discovery of Pyridyl Bis(oxy)dibenzimidamide Derivatives as Selective Matriptase Inhibitors.

    Goswami, Rajeev; Mukherjee, Subhendu; Wohlfahrt, Gerd; Ghadiyaram, Chakshusmathi; Nagaraj, Jwala; Chandra, Beeram Ravi; Sistla, Ramesh K; Satyam, Leena K; Samiulla, Dodheri S; Moilanen, Anu; Subramanya, Hosahalli S; Ramachandra, Murali

    2013-12-12

    Matriptase belongs to trypsin-like serine proteases involved in matrix remodeling/degradation, growth regulation, survival, motility, and cell morphogenesis. Herein, we report a structure-based approach, which led to the discovery of sulfonamide and amide derivatives of pyridyl bis(oxy)benzamidine as potent and selective matriptase inhibitors. Co-crystal structures of selected compounds in complex with matriptase supported compound designing. Additionally, WaterMap analyses indicated the possibility of occupying a distinct pocket within the catalytic domain, exploration of which resulted in >100-fold improvement in potency. Co-crystal structure of 10 with matriptase revealed critical interactions leading to potent target inhibition and selectivity against other serine proteases. PMID:24900621

  5. Redetermined crystal structure of N-(β-carb-oxy-eth-yl)-α-isoleucine.

    Chandrarekha, M; Srinivasan, N; Krishnakumar, R V

    2015-09-01

    Redetermination of the crystal structure of N-(β-carb-oxy-eth-yl)-α-isoleucine, C9H18N2O3, reported earlier by Nehls et al. [Acta Cryst. (2013), E69, o172-o173], was undertaken in which the ionization state assigned to the mol-ecule as unionized has been modified as zwitterionic in the present work. Single-crystal X-ray intensity data obtained from freshly grown crystals and freely refining the amino H atoms provide enhanced refinement and structural parameters, particularly the hydrogen-bonding scheme. N-H⋯O hydrogen bonds dominate the inter-molecular inter-actions along with a C-H⋯O hydrogen bond. The inter-molecular inter-action pattern is a three-dimensional network. The structure was refined as a two-component perfect inversion twin. PMID:26396893

  6. Numerical Simulation on Supersonic Flow in High-Velocity Oxy-Fuel Thermal Spray Gun

    Hiroshi KATANODA; Hideki YAMAMOTO; Kazuyasu MATSUO

    2006-01-01

    This paper analyzes the behaviour of coating particles as well as the gas flow both inside and outside of the High-Velocity Oxy-Fuel (HVOF) thermal spray gun by using a quasi-one-dimensional analysis and a numerical simulation. The HVOF gun in the present analysis is an axially symmetric convergent-divergent nozzle with the design Mach number of 2.0. From the present analysis, the distributions of velocity and temperature of the coating particles flying inside and outside of the HVOF gun are predicted. The velocity and temperature of the coating particles at the exit of the gun calculated by the present method agree well with the previous experimental results. Therefore, the present method of calculation is considered to be useful for predicting the HVOF gas and particle flows.

  7. Aerodynamic Study on Supersonic Flows in High-Velocity Oxy-Fuel Thermal Spray Process

    Hiroshi KATANODA; Takeshi MATSUOKA; Seiji KURODA; Jin KAWAKITA; Hirotaka FUKANUMA; Kazuyasu MATSUO

    2005-01-01

    @@ To clarify the characteristics of gas flow in high velocity oxy-fuel (HVOF) thermal spray gun, aerodynamic research is performed using a special gun. The gun has rectangular cross-sectional area and sidewalls of optical glass to visualize the internal flow. The gun consists of a supersonic nozzle with the design Mach number of 2.0 followed by a straight passage called barrel. Compressed dry air up to 0.78 MPa is used as a process gas instead of combustion gas which is used in a commercial HVOF gun. The high-speed gas flows with shock waves in the gun and jets are visualized by schlieren technique. Complicated internal and external flow-fields containing various types of shock wave as well as expansion wave are visualized.

  8. Optimization and Characterization of High Velocity Oxy-fuel Sprayed Coatings: Techniques, Materials, and Applications

    Maria Oksa

    2011-09-01

    Full Text Available In this work High Velocity Oxy-fuel (HVOF thermal spray techniques, spraying process optimization, and characterization of coatings are reviewed. Different variants of the technology are described and the main differences in spray conditions in terms of particle kinetics and thermal energy are rationalized. Methods and tools for controlling the spray process are presented as well as their use in optimizing the coating process. It will be shown how the differences from the starting powder to the final coating formation affect the coating microstructure and performance. Typical properties of HVOF sprayed coatings and coating performance is described. Also development of testing methods used for the evaluation of coating properties and current status of standardization is presented. Short discussion of typical applications is done.

  9. Technical and economic aspects of oxygen separation for oxy-fuel purposes

    Chorowski Maciej

    2015-03-01

    Full Text Available Oxy combustion is the most promising technology for carbon dioxide, originated from thermal power plants, capture and storage. The oxygen in sufficient quantities can be separated from air in cryogenic installations. Even the state-of-art air separation units are characterized by high energy demands decreasing net efficiency of thermal power plant by at least 7%. This efficiency decrease can be mitigated by the use of waste nitrogen, e.g., as the medium for lignite drying. It is also possible to store energy in liquefied gases and recover it by liquid pressurization, warm-up to ambient temperature and expansion. Exergetic efficiency of the proposed energy accumulator may reach 85%.

  10. Thermodynamic and economic analysis of a gas turbine combined cycle plant with oxy-combustion

    Kotowicz, Janusz; Job, Marcin

    2013-12-01

    This paper presents a gas turbine combined cycle plant with oxy-combustion and carbon dioxide capture. A gas turbine part of the unit with the operating parameters is presented. The methodology and results of optimization by the means of a genetic algorithm for the steam parts in three variants of the plant are shown. The variants of the plant differ by the heat recovery steam generator (HRSG) construction: the singlepressure HRSG (1P), the double-pressure HRSG with reheating (2PR), and the triple-pressure HRSG with reheating (3PR). For obtained results in all variants an economic evaluation was performed. The break-even prices of electricity were determined and the sensitivity analysis to the most significant economic factors were performed.

  11. Oxi-DIGE: A novel proteomic approach for detecting and quantifying carbonylated proteins.

    Baraibar, Martin; Ladouce, Romain; Friguet, Bertrand

    2014-10-01

    Proteins are involved in key cellular functions and our health and wellness depends on their quality. Accumulation of oxidatively damaged proteins is a hallmark of deleterious processes such increased oxidative stress, chronic inflammation, ageing and age-related diseases. Thus, quantifying and identifying oxidized proteins is a biomarker of choice for monitoring biological ageing and/or the efficiency of anti-oxidant, ant-inflammatory and anti-ageing therapies. However, the absence of reliable tools for analyses has inhibited its establishment as the gold standard for measuring the efficacy of anti-ageing and age related diseases interventions. Herein, we present a novel proteomics technology, named Oxi-DIGE?, which provides a significant improvement in terms of specificity, reproducibility and statistical support for proteomic analysis of carbonylated proteins. In Oxi-DIGE, protein carbonyls are labelled with fluorescent hydrazide probes that bind specifically to carbonyl groups in proteins. Experimental groups (e.g. control and experimental samples) are labelled with different flurophore-binded hydrazides that fluoresce light at different wavelengths, producing different colour fluorescence. Thus samples from different experimental groups are co-resolved on a single 2D gel. Increased accuracy is provided due to: (i) reduced false positives by using an exogenous synthetic fluorescent tag; (ii) multiplexing, that is the possibility to run multiple samples on the same gel, (iii) the use of an internal standard on each gel which eliminates inter-gel variations and provides an increased statistical confidence. In addition, the resolution of the carbonyl groups is improved, forming distinct spots that can be identified by mass spectrometry. ?Patent Application (M. Baraibar, R. Ladouce., B. Friguet, A method for detecting and/or quantifying carbonylated proteins (WO/2012/175519) filed by UPMC and referring to the technology described in this abstract. PMID:26461312

  12. Flame structure and NO generation in oxy-fuel combustion at high pressures

    A numerical study of oxy-fuel combustion has been carried out in the pressure range of 0.1-3 MPa with methane as the fuel and carbondioxide-diluted oxygen with trace amount of nitrogen (termed here as cair) as the oxidant. The flame structure and NO generation rate have been calculated using the flamelet model with the detailed GRI 3.0 mechanism for two oxygen concentrations of 23.3% and 20% by weight in the oxidant at a strain rate of 40 s-1 (corresponding to a scalar dissipation rate of 1 s-1). It is observed that, for the reference case of 23.3 wt.% of oxygen, as the pressure increases, the peak temperature of the flame increases rapidly up to a pressure of 0.5 MPa, and more gradually at higher pressures. The concentrations of important intermediate radicals such as CH3, H and OH decrease considerably with increasing pressure while NO concentration follows the same trend as the temperature. Reducing the oxygen concentration to 20% by weight leads to an order of magnitude reduction in NO concentration. Also, for pressures greater than 0.3 MPa, the NO concentration decreases with increasing pressure in spite of the increasing peak flame temperatures. This can be attributed to the increasing domination of recombination reactions leading to less availability of the intermediate radicals H and OH which are necessary for the formation of NO by the thermal route. It is concluded that a stable, low NOx oxy-fuel flame can be obtained at high pressures at slightly increased dilution of oxygen

  13. Numerical simulations of the industrial circulating fluidized bed boiler under air- and oxy-fuel combustion

    Measured and numerical results of air-fuel combustion process within large scale industrial circulating fluidized bed (CFB) boiler is presented in this paper. For numerical simulations the industrial compact CFB boiler was selected. Numerical simulations were carried out using three-dimensional model where the dense particulate transport phenomenon was simultaneously modelled with combustion process. The fluidization process was modelled using the hybrid Euler-Lagrange approach. The impact of the geometrical model simplification on predicted mass distribution and temperature profiles over CFB boiler combustion chamber two kinds of geometrical models were used, namely the complete model which consist of combustion chamber, solid separators, external solid super-heaters and simplified boiler geometry which was reduced to the combustion chamber. The evaluated temperature and pressure profiles during numerical simulations were compared against measured data collected during boiler air-fuel operation. Collected data was also used for validating numerical model of the oxy-fuel combustion model. Stability of the model and its sensitivity on changes of several input parameters were studied. The comparison of the pressure and temperature profiles for all considered cases gave comparable trends in contrary to measured data. Moreover, some additional test was carried out the check the influence of radiative heat transfer on predicted temperature profile within the CFB boiler. - Highlights: • Hybrid Euler-Lagrange approach was used for modelling particle transport, air- and oxy-fuel combustion process. • Numerical results were validated against measured data. • The influence of different boiler operating conditions on calculated temperature profile was investigated. • New strategy for resolving particle transport in circulating fluidized bed was shown

  14. Oxidation mechanisms of materials for heat exchanging components in CO 2 /H 2 O-containing gases relevant to oxy-fuel

    Olszewski, Tomasz

    2012-01-01

    In the context of CO2 emission reduction, the oxy-fuel technology provides a promising option applicable in centralized energy production. This technology is based on pulverized coal combustion with pure oxygen instead of air. Different from the conventional systems, metallic heat exchanging components in the oxy-fuel plants will be subjected to service environments containing high amounts of CO2 and H2O. In the present study the oxidation behaviour of selected ferritic/martensitic and austen...

  15. Ignition of suspensions of coal and biomass particles in air and oxy-fuel for Carbon Capture and Storage (CCS) and climate change mitigation

    Trabadela Robles, Ignacio

    2015-01-01

    Carbon Capture and Storage (CCS) is a legitimate technology option that should be part of a balanced portfolio of mitigation technologies available Post-Kyoto Protocol framework after Paris 2015 and beyond the 2020s or the cost achieving 2 degrees Celsius stabilisation scenario will significantly increase. Oxy-fuel combustion as a CCS technology option increases fuel flexibility. Additionally, oxy-biomass as a bio-energy with CCS (BECCS) technology can achieve negative carbon d...

  16. Modeling CO[subscript 2] Chemical Effects on CO Formation in Oxy-Fuel Diffusion Flames Using Detailed, Quasi-Global, and Global Reaction Mechanisms

    Chen, Lei; Ghoniem, Ahmed F.

    2013-01-01

    Interest in oxy-fuel combustion as one of the leading carbon capture technologies has grown significantly in the past two decades. Experimental studies have shown higher CO concentration in oxy-fuel diffusion flames than in traditional air-fuel flames of both gaseous and solid fuels. The higher CO concentration changes the flame profiles, and it may have impacts on pollutants formation. This article presents a numerical study regarding the chemical effects of CO[subscript 2] on CO formation i...

  17. Formation and Control of Sulfur Oxides in Sour Gas Oxy-Combustion: Prediction Using a Reactor Network Model

    Bongartz, Dominik

    2015-11-19

    © 2015 American Chemical Society. Sour natural gas currently requires expensive gas cleanup before it can be used in power generation because it contains large amounts of hydrogen sulfide (H2S) and carbon dioxide (CO2) that entail a low heating value and highly corrosive combustion products. A potential alternative is to use the gas directly in a gas turbine process employing oxy-fuel combustion, which could eliminate the need for gas cleanup while also enabling the application of carbon capture and sequestration, possibly combined with enhanced oil recovery (EOR). However, the exact influence of an oxy-fuel environment on the combustion products of sour gas has not been quantified yet. In this work, we used a reactor network model for the combustor and the gas turbine together with our recently assembled and validated detailed chemical reaction mechanism for sour gas combustion to investigate the influence of some basic design parameters on the combustion products of natural gas and sour gas in CO2 or H2O diluted oxy-fuel combustion as well as in conventional air combustion. Our calculations show that oxy-fuel combustion produces up to 2 orders of magnitude less of the highly corrosive product sulfur trioxide (SO3) than air combustion, which clearly demonstrates its potential in handling sulfur containing fuels. Unlike in air combustion, in oxy-fuel combustion, SO3 is mainly formed in the flame zone of the combustor and is then consumed as the combustion products are cooled in the dilution zone of the combustor and the turbine. In oxy-fuel combustion, H2O dilution leads to a higher combustion efficiency than CO2 dilution. However, if the process is to be combined with EOR, CO2 dilution makes it easier to comply with the very low levels of oxygen (O2) required in the EOR stream. Our calculations also show that it might even be beneficial to operate slightly fuel-rich because this simultaneously decreases the O2 and SO3 concentration further. The flame zone

  18. Long-term wheel running changes on sensorimotor activity and skeletal muscle in male and female mice of accelerated senescence

    Sanchez-Roige, Sandra; Jaume F Lalanza; Alvarez-López, María Jesús; Cosín-Tomás, Marta; Griñan-Ferré, Christian; Pallàs, Merce; Kaliman, Perla; Rosa M. Escorihuela

    2014-01-01

    The senescence-accelerated mouse prone 8 (SAMP8) is considered a useful non-transgenic model for studying aspects of aging. Using SAM resistant 1 (SAMR1) as controls, the long-term effects of wheel running on skeletal muscle adaptations and behavioral traits were evaluated in senescent (P8) and resistant (R1) male and female mice. Long-term wheel running (WR) led to increases in locomotor activity, benefits in sensorimotor function, and changes in body weight in a gender-dependent manner. WR ...

  19. Long-term wheel running changes on sensorimotor activity and skeletal muscle in male and female mice of accelerated senescence.

    Sanchez-Roige, Sandra; Lalanza, Jaume F; Alvarez-López, María Jesús; Cosín-Tomás, Marta; Griñan-Ferré, Christian; Pallàs, Merce; Kaliman, Perla; Escorihuela, Rosa M

    2014-01-01

    The senescence-accelerated mouse prone 8 (SAMP8) is considered a useful non-transgenic model for studying aspects of aging. Using SAM resistant 1 (SAMR1) as controls, the long-term effects of wheel running on skeletal muscle adaptations and behavioral traits were evaluated in senescent (P8) and resistant (R1) male and female mice. Long-term wheel running (WR) led to increases in locomotor activity, benefits in sensorimotor function, and changes in body weight in a gender-dependent manner. WR increased body weight and baseline levels of locomotor activity in female mice and improved balance and strength in male mice, compared to sedentary-control mice. WR resulted in key metabolic adaptations in skeletal muscle, associated with an increased activity of the sirtuin 1-AMP-activated protein kinase (AMPK)-PGC-1 alpha axis and changes in vascular endothelial growth factor A (Vegfa), glucose transporter type 4 (Glut4), and Cluster of Differentiation 36 (Cd36) gene expression. Overall, our data indicate that activity, balance, and strength decrease with age and that long-term WR may significantly improve the motor function in a mouse model of senescence in a gender-dependent manner. PMID:25129573

  20. Accelerated senescence and enhanced disease resistance in hybrid chlorosis lines derived from interspecific crosses between tetraploid wheat and Aegilops tauschii.

    Hiroki Nakano

    Full Text Available Hybrid chlorosis, a type of hybrid incompatibility, has frequently been reported in inter- and intraspecific crosses of allopolyploid wheat. In a previous study, we reported some types of growth abnormalities such as hybrid necrosis and observed hybrid chlorosis with mild or severe abnormalities in wheat triploids obtained in crosses between tetraploid wheat cultivar Langdon and four Ae. tauschii accessions and in their derived synthetic hexaploids. However, the molecular mechanisms underlying hybrid chlorosis are not well understood. Here, we compared cytology and gene expression in leaves to characterize the abnormal growth in wheat synthetics showing mild and severe chlorosis. In addition, we compared disease resistance to wheat blast fungus. In total 55 and 105 genes related to carbohydrate metabolism and 53 and 89 genes for defense responses were markedly up-regulated in the mild and severe chlorosis lines, respectively. Abnormal chloroplasts formed in the mesophyll cells before the leaves yellowed in the hybrid chlorosis lines. The plants with mild chlorosis showed increased resistance to wheat blast and powdery mildew fungi, although significant differences only in two, third internode length and maturation time, out of the examined agricultural traits were found between the wild type and plants showing mild chlorosis. These observations suggest that senescence might be accelerated in hybrid chlorosis lines of wheat synthetics. Moreover, in wheat synthetics showing mild chlorosis, the negative effects on biomass can be minimized, and they may show substantial fitness under pathogen-polluted conditions.

  1. Accelerated senescence and enhanced disease resistance in hybrid chlorosis lines derived from interspecific crosses between tetraploid wheat and Aegilops tauschii.

    Nakano, Hiroki; Mizuno, Nobuyuki; Tosa, Yukio; Yoshida, Kentaro; Park, Pyoyun; Takumi, Shigeo

    2015-01-01

    Hybrid chlorosis, a type of hybrid incompatibility, has frequently been reported in inter- and intraspecific crosses of allopolyploid wheat. In a previous study, we reported some types of growth abnormalities such as hybrid necrosis and observed hybrid chlorosis with mild or severe abnormalities in wheat triploids obtained in crosses between tetraploid wheat cultivar Langdon and four Ae. tauschii accessions and in their derived synthetic hexaploids. However, the molecular mechanisms underlying hybrid chlorosis are not well understood. Here, we compared cytology and gene expression in leaves to characterize the abnormal growth in wheat synthetics showing mild and severe chlorosis. In addition, we compared disease resistance to wheat blast fungus. In total 55 and 105 genes related to carbohydrate metabolism and 53 and 89 genes for defense responses were markedly up-regulated in the mild and severe chlorosis lines, respectively. Abnormal chloroplasts formed in the mesophyll cells before the leaves yellowed in the hybrid chlorosis lines. The plants with mild chlorosis showed increased resistance to wheat blast and powdery mildew fungi, although significant differences only in two, third internode length and maturation time, out of the examined agricultural traits were found between the wild type and plants showing mild chlorosis. These observations suggest that senescence might be accelerated in hybrid chlorosis lines of wheat synthetics. Moreover, in wheat synthetics showing mild chlorosis, the negative effects on biomass can be minimized, and they may show substantial fitness under pathogen-polluted conditions. PMID:25806790

  2. Accelerated Senescence and Enhanced Disease Resistance in Hybrid Chlorosis Lines Derived from Interspecific Crosses between Tetraploid Wheat and Aegilops tauschii

    Hiroki Nakano; Nobuyuki Mizuno; Yukio Tosa; Kentaro Yoshida; Pyoyun Park; Shigeo Takumi

    2015-01-01

    Hybrid chlorosis, a type of hybrid incompatibility, has frequently been reported in inter- and intraspecific crosses of allopolyploid wheat. In a previous study, we reported some types of growth abnormalities such as hybrid necrosis and observed hybrid chlorosis with mild or severe abnormalities in wheat triploids obtained in crosses between tetraploid wheat cultivar Langdon and four Ae. tauschii accessions and in their derived synthetic hexaploids. However, the molecular mechanisms underlyin...

  3. Proof of concept for integrating oxy-fuel combustion and the removal of all pollutants from a coal fired flame

    Ochs, Thomas L.; Patrick, Brian (Jupiter Oxygen Corp.); Oryshchyn, Danylo B.; Gross, Alex (Jupiter Oxygen Corp.); Summers, Cathy A.; Simmons, William (CoalTeck LLC); Schoenfield, Mark (Jupiter Oxygen Corp.); Turner, Paul C.

    2005-01-01

    The USDOE/Albany Research Center and Jupiter Oxygen Corporation, working together under a Cooperative Research and Development Agreement, have demonstrated proof-of-concept for the integration of Jupiter’s oxy-fuel combustion and an integrated system for the removal of all stack pollutants, including CO2, from a coal-fired flame. The components were developed using existing process technology with the addition of a new oxy-coal combustion nozzle. The results of the test showed that the system can capture SOx, NOx, particulates, and even mercury as a part of the process of producing liquefied CO2 for sequestration. This is part of an ongoing research project to explore alternative methods for CO2 capture that will be applicable to both retrofit and new plant construction.

  4. Influence of manganese incorporation on structure, surface and As(III)/As(V) removal capacity of iron oxy-hydroxides

    Tresintsi, Sofia; Simeonidis, Konstantinos; Mitrakas, Manassis

    2013-04-01

    Iron oxy-hydroxides are well defined As(V) adsorbents dominating in water treatment market. The main drawback of these adsorbents, as well as of all commercial one, is their significantly low adsorption capacity for As(III). A breakthrough for improving As(III) adsorption of iron oxy-hydroxides may come by the MnO2incorporation. However, MnO2 decreases the total arsenic capacity proportionally to its percentage since its efficiency for As(V) is much lower than that of an iron oxy-hydroxide. It is concluded that an ideal adsorbent capable for high and simultaneous As(III) and As(V) removal should be consisted of a binary Fe(III)-Mn(IV) oxy-hydroxide both efficient for As(III) oxidation, due to Mn(IV) presence, and capture of As(V) due to a high positively surface charge density. This work studies the optimum parameters at the synthesis of single Fe and binary Fe/Mn oxy-hydroxides in a continuous flow kilogram-scale production reactor through the precipitation of FeSO4 in the pH range 3-12, under intense oxidative conditions using H2O2/KMnO4, that maximize arsenic adsorption. The evaluation of their efficiency was based on its As(III) and As(V) adsorption capacity (Q10-index) at equilibrium concentration equal to drinking water regulation limit (Ce= 10 μg/L) in NSF challenge water. The pH of synthesis was found to decisively affect, the structure, surface configuration and Q10-index. As a result, both single Fe and binary Fe/Mn oxy-hydroxides prepared at pH 4, which consist of schwertmannite and Mn(IV)-feroxyhyte respectively, were qualified according to their highest Q10-index of 13±0.5 μg As(V)/ mg for a residual arsenic concentration of 10 μg/L at an equilibrium pH 7. The high surface charge and the activation of an ion-exchange mechanism between SO42- adsorbed in the Stern layer and arsenate ions were found to significantly contribute to the increased adsorption capacity. The Q10-index for As(III) of Fe/Mn adsorbent at equilibrium pH 7 was 6.7 μg/mg, which

  5. Crystal structure of 3-(2,5-di­meth­oxy­phen­yl)propionic acid

    Bugenhagen, Bernhard; Al Jasem, Yosef; AlAzani, Mariam; Thiemann, Thies

    2015-01-01

    In the crystal of the title compound, C11H14O4, the aromatic ring is almost coplanar with the 2-position meth­oxy group with which it subtends a dihedral of 0.54 (2)°, while the 5-position meth­oxy group makes a corresponding dihedral angle of just 5.30 (2)°. The angle between the mean planes of the aromatic ring and the propionic acid group is 78.56 (2)°. The fully extended propionic side chain is in a trans configuration with a C—C—C—C torsion angle of −172.25 (7)°. In the crystal, hydrogen...

  6. (2E,6E)-2,6-Bis(2-fluoro-5-meth-oxy-benzyl-idene)cyclo-hexan-1-one.

    Chen, Linfeng; Zhang, Li; Wang, Zhe; Wu, Yunjie; Liang, Guang

    2010-01-01

    The title compound, C(22)H(20)F(2)O(3), a derivative of curcumin, crystallized with two independent mol-ecules in the asymmetric unit. The mean planes of the two 2-fluoro-5-meth-oxy-phenyl groups are aligned at 24.88 (11)° in one mol-ecule and 24.19 (15)° in the other. The dihedral angles between the mean plane of the penta-1,4-dien-3-one group and those of the two 2-fluoro-5-meth-oxy-phenyl rings are 51.16 (11) and 49.16 (10)° in the first mol-ecule, and 45.69 (15) and 54.00 (14)° in the second. The mol-ecules adopt E configurations about the central olefinic bonds. PMID:21589587

  7. Modelling and kinetics studies of a corn-rape blend combustion in an oxy-fuel atmosphere.

    López, R; Fernández, C; Martínez, O; Sánchez, M E

    2015-05-01

    A kinetic oxy-combustion study of a previously optimized lignocellulose blend is proposed. Kinetic and diffusion control mechanism are considered. The proposed correlations fit properly with the experimental results and diffusion effects are identified as be important enough to be taken into account. Afterwards, with the results obtained in the kinetic study, a detailed consecutive and parallel kinetic scheme is proposed for modelling the oxy-combustion of the blend. A discussion of the temperature and concentration profiles are included. Variation of products final distribution is considered. Smaller particles than 0.001 m are proposed for reducing temperature and concentration profiles and obtaining a good final product distribution. CO2-char reaction is identified as one of the most important step to be optimized for obtaining the lowest final residue. In this study, char is mainly oxidised at 950 K and this situation is attributed to an optimized blending of the bioresidues. PMID:25731924

  8. The reactivity of lattice carbon and nitrogen species in molybdenum (oxy)carbonitrides prepared by single-source routes

    Highlights: ► Molybdenum (oxy)carbonitrides have been prepared from single source routes. ► Nitrogen species are more reactive than carbon species within the carbonitrides. ► The reactivity of nitrogen species is a function of carbonitride composition. -- Abstract: Molybdenum (oxy)carbonitrides of different compositions have been prepared from hexamethylenetetramine molybdate and ethylenediamine molybdate precursors and the reactivity of the lattice carbon and nitrogen species within them has been determined by temperature programmed reduction and thermal volatilisation studies. Nitrogen is found to be much more reactive than carbon and the nature of its reactivity is influenced by composition with the presence of carbon enhancing the reactivity of nitrogen. The difference in reactivity observed indicates that molybdenum carbonitrides are not suitable candidates as reagents for which the simultaneous loss of nitrogen and carbon from the lattice would be desirable.

  9. Thermodynamic evaluation of supercritical oxy-type power plant with high-temperature three-end membrane for air separation

    Kotowicz Janusz

    2014-09-01

    Full Text Available Among the technologies which allow to reduce greenhouse gas emissions, mainly of carbon dioxide, special attention deserves the idea of ‘zero-emission’ technology based on boilers working in oxy-combustion technology. In the paper a thermodynamic analysis of supercritical power plant fed by lignite was made. Power plant consists of: 600 MW steam power unit with live steam parameters of 650 °C/30 MPa and reheated steam parameters of 670 °C/6 MPa; circulating fluidized bed boiler working in oxy-combustion technology; air separation unit and installation of the carbon dioxide compression. Air separation unit is based on high temperature membrane working in three-end technology. Models of steam cycle, circulation fluidized bed boiler, air separation unit and carbon capture installation were made using commercial software. After integration of these models the net electricity generation efficiency as a function of the degree of oxygen recovery in high temperature membrane was analyzed.

  10. Towards a two-dimensional laser induced breakdown spectroscopy mapping of liquefied petroleum gas and electrolytic oxy-hydrogen flames

    Two-dimensional mapping of the laser-induced breakdown spectroscopy (LIBS) signal of chemical species information in liquefied petroleum gas (LPG) and electrolytic oxy-hydrogen (EOH) flames was performed with in situ flame diagnostics. Base LIBS signals averaged from measurements at wavelengths of 320 nm to 350 nm describe the density information of a flame. The CN LIBS signal provides the concentration of fuel, while the H/O signal represents the fuel/air equivalence ratio. Here, we demonstrate the meaningful use of two-dimensional LIBS mappings to provide key combustion information, such as density, fuel concentration, and fuel/air equivalence ratio. - Highlights: • 2-dimensional mapping of chemical species information is achieved by LIBS in flames. • We consider LPG–EOH (electrolytic oxy-hydrogen) flame for its chemical analysis. • The optical emission spectroscopy (OES) is used for validation of the LIBS results. • LIBS signal provides additional chemical information not attainable via OES

  11. Thermodynamic analysis of the double Brayton cycle with the use of oxy combustion and capture of CO2

    Ziółkowski, Paweł; Zakrzewski, Witold; Kaczmarczyk, Oktawia; Badur, Janusz

    2013-06-01

    In this paper, thermodynamic analysis of a proposed innovative double Brayton cycle with the use of oxy combustion and capture of CO2, is presented. For that purpose, the computation flow mechanics (CFM) approach has been developed. The double Brayton cycle (DBC) consists of primary Brayton and secondary inverse Brayton cycle. Inversion means that the role of the compressor and the gas turbine is changed and firstly we have expansion before compression. Additionally, the workingfluid in the DBC with the use of oxy combustion and CO2 capture contains a great amount of H2O and CO2, and the condensation process of steam (H2O) overlaps in negative pressure conditions. The analysis has been done for variants values of the compression ratio, which determines the lowest pressure in the double Brayton cycle.

  12. 25,26,27,28-Tetra­kis(3-bromo­benzyl­oxy)calix[4]arene

    Lee, Eunji; Moon, Suk-Hee; Kim, Tae Ho; Park, Ki-Min

    2011-01-01

    In the title compound, C56H44Br4O4, the calix[4]arene unit displays the 1,2-alternate conformation with crystallograpically imposed inversion symmetry. The four phen­oxy rings of the calix[4]arene unit are twisted about the mean plane defined by the four methyl­ene C atoms bridging the benzene rings, with dihedral angles of 46.73 (6) and 66.11 (5)°. The dihedral angle between adjacent phen­oxy rings is 74.75 (7)°. The two pendant bromo­phenyl rings on the same side of the calix[4]arene unit a...

  13. Development and application of a solidphase extraction method for simultaneousdetermination of PAHs, oxy-PAHs andazaarenes in water samples

    WANG Yu

    2012-01-01

    In this study, a solid phase extraction (SPE) method was developed that can be used to extract a wide range of polycyclic aromatic compounds (PACs), including polycyclic aromatic hydrocarbons (PAHs), oxygenated PAHs (oxy-PAHs) and azaarenes, from water samples. Three commercially available SPE materials, i.e. Oasis HLB, ISOLUTE C2/C18 (EC) and ISOLUTE PAH, were tested for their capability to accomplish the extraction, and two were chosen for further optimization. Several different combination...

  14. Monitoring of Internet Forums to Evaluate Reactions to the Introduction of Reformulated OxyContin to Deter Abuse

    McNaughton, Emily C; Coplan, Paul M; Black, Ryan A.; Weber, Sarah E.; Chilcoat, Howard D.; Butler, Stephen F.

    2014-01-01

    Background Reformulating opioid analgesics to deter abuse is one approach toward improving their benefit-risk balance. To assess sentiment and attempts to defeat these products among difficult-to-reach populations of prescription drug abusers, evaluation of posts on Internet forums regarding reformulated products may be useful. A reformulated version of OxyContin (extended-release oxycodone) with physicochemical properties to deter abuse presented an opportunity to evaluate posts about the re...

  15. Oxy-fuel combustion of coal and biomass, the effect on radiative and convective heat transfer and burnout

    Smart, John P.; Patel, Rajeshriben; Riley, Gerry S. [RWEnpower, Windmill Hill Business Park, Whitehill Way, Swindon, Wiltshire SN5 6PB, England (United Kingdom)

    2010-12-15

    This paper focuses on results of co-firing coal and biomass under oxy-fuel combustion conditions on the RWEn 0.5 MWt Combustion Test Facility (CTF). Results are presented of radiative and convective heat transfer and burnout measurements. Two coals were fired: a South African coal and a Russian Coal under air and oxy-fuel firing conditions. The two coals were also co-fired with Shea Meal at a co-firing mass fraction of 20%. Shea Meal was also co-fired at a mass fraction of 40% and sawdust at 20% with the Russian Coal. An IFRF Aerodynamically Air Staged Burner (AASB) was used. The thermal input was maintained at 0.5 MWt for all conditions studied. The test matrix comprised of varying the Recycle Ratio (RR) between 65% and 75% and furnace exit O{sub 2} was maintained at 3%. Carbon-in-ash samples for burnout determination were also taken. Results show that the highest peak radiative heat flux and highest flame luminosity corresponded to the lowest recycle ratio. The effect of co-firing of biomass resulted in lower radiative heat fluxes for corresponding recycle ratios. Furthermore, the highest levels of radiative heat flux corresponded to the lowest convective heat flux. Results are compared to air firing and the air equivalent radiative and convective heat fluxes are fuel type dependent. Reasons for these differences are discussed in the main text. Burnout improves with biomass co-firing under both air and oxy-fuel firing conditions and burnout is also seen to improve under oxy-fuel firing conditions compared to air. (author)

  16. Analysis of cumulative energy consumption in an oxy-fuel combustion power plant integrated with a CO2 processing unit

    Highlights: • Oxy-fuel combustion is promising CCS technology. • Sum of direct and indirect energy consumption ought to be consider. • This sum is expressed by cumulative energy consumption. • Input–output analysis is adequate method of CCS modeling. - Abstract: A balance of direct energy consumption is not a sufficient tool for an energy analysis of an oxy-fuel combustion power plant because of the indirect consumption of energy in preceding processes in the energy-technological set of interconnections. The sum of direct and indirect consumption expresses cumulative energy consumption. Based on the “input–output” model of direct energy consumption the mathematical model of cumulative energy consumption concerning an integrated oxy-fuel combustion power plant has been developed. Three groups of energy carriers or materials are to be distinguished, viz. main products, by-products and external supplies not supplementing the main production. The mathematical model of the balance of cumulative energy consumption based on the assumption that the indices of cumulative energy consumption of external supplies (mainly fuels and raw materials) are known a’priori. It results from weak connections between domestic economy and an integrated oxy-fuel combustion power plant. The paper presents both examples of the balances of direct and cumulative energy consumption. The results of calculations of indices of cumulative energy consumption concerning main products are presented. A comparison of direct and cumulative energy effects between three variants has been worked out. Calculations of the indices of cumulative energy consumption were also subjected to sensitive analysis. The influence of the indices of cumulative energy consumption of external supplies (input data), as well as the assumption concerning the utilization of solid by-products of the combustion process have been investigated

  17. Impact of Oxy-Fuel Conditions on Elemental Mercury Re-Emission in Wet Flue Gas Desulfurization Systems.

    Fernández-Miranda, Nuria; Lopez-Anton, M Antonia; Torre-Santos, Teresa; Díaz-Somoano, Mercedes; Martínez-Tarazona, M Rosa

    2016-07-01

    This study evaluates some of the variables that may influence mercury retention in wet flue gas desulfurization (WFGD) plants, focusing on oxy-coal combustion processes and differences when compared with atmospheres enriched in N2. The main drawback of using WFGD for mercury capture is the possibility of unwanted reduction of dissolved Hg(2+), leading to the re-emission of insoluble elemental mercury (Hg(0)), which decreases efficiency. To acquire a better understanding of the mercury re-emission reactions in WFGD systems, this work analyses different variables that influence the behavior of mercury in slurries obtained from two limestones, under an oxy-combustion atmosphere. The O2 supplied to the reactor, the influence of the pH, the concentration of mercury in the gas phase, and the enhancement of mercury in the slurry were the variables considered. The study was performed at laboratory scale, where possible reactions between the components in the scrubber can be individually evaluated. It was found that in an oxy-combustion atmosphere (mostly CO2), the re-emission of Hg(0) is lower than under a N2-enriched atmosphere, and the mercury is mainly retained as Hg(2+) in the liquid phase. PMID:27329988

  18. The effects of de-humidification and O{sub 2} direct injection in oxy-PC combustion

    Choi, C.G.; Na, I.H.; Lee, J.W.; Chae, T.Y.; Yang, W. [Korea Insitute of Industrial Technology, Seoul (Korea, Republic of). Energy System R and D Dept.

    2013-07-01

    This study is aimed to derive effects of de-humidification and O{sub 2} direct injection in oxy-PC combustion system. Temperature distribution and flue gas composition were observed for various air and oxy-fuel conditions such as effect of various O{sub 2} concentration of total oxidant, O{sub 2} concentration of primary stream and O{sub 2} direct injection through 0-D heat and mass balance calculation and experiments in the oxy-PC combustion system of 0.3 MW scale in KITECH (Korea Institute of Industrial Technology). Flame attachment characteristic related to O{sub 2} direct injection was also observed experimentally. We found that FEGT (furnace exit gas temperature) of 100% de-humidification to oxidizer is lower than humidification condition; difference between two conditions is lower than 20 C in all cases. The efficiency changing of combustion was negligible in O{sub 2} direct injection. But O{sub 2} direct injection should be carefully designed to produce a stable flame.

  19. Crystal structure of 5-{4′-[(2-{2-[2-(2-ammonio­eth­oxy)eth­oxy]eth­oxy}eth­yl)carbamo­yl]-4-meth­oxy-[1,1′-biphen­yl]-3-yl}-3-oxo-1,2,5-thia­diazo­lidin-2-ide 1,1-dioxide: a potential inhibitor of the enzyme protein tyrosine phosphatase 1B (PTP1B)

    Ruddraraju, Kasi Viswanatharaju; Hillebrand, Roman; Barnes, Charles L.; Gates, Kent S.

    2015-01-01

    The title compound, C24H32N4O8S, (I), crystallizes as a zwitterion. The terminal amine N atom of the [(2-{2-[2-(2-ammonio­eth­oxy)eth­oxy]eth­oxy}eth­yl)carbamo­yl] side chain is protonated, while the 1,2,5-thia­diazo­lidin-3-one 1,1-dioxide N atom is deprotonated. The side chain is turned over on itself with an intra­molecular N—H⋯O hydrogen bond. The 1,2,5-thia­diazo­lidin-3-one 1,1-dioxide ring has an envelope conformation with the aryl-substituted N atom as the flap. Its mean plane is inclined by 62.87 (8)° to the aryl ring to which it is attached, while the aryl rings of the biphenyl unit are inclined to one another by 20.81 (8)°. In the crystal, mol­ecules are linked by N—H⋯O and N—H⋯N hydrogen bonds, forming slabs lying parallel to (010). Within the slabs there are C—H⋯O and C—H⋯N hydrogen bonds and C—H⋯π inter­actions present. PMID:26029383

  20. Adsorption Mechanisms of Trivalent Gold onto Iron Oxy-Hydroxides: From the Molecular Scale to the Model

    Cancès, Benjamin; Benedetti, Marc; Farges, François; Brown, Gordon E.

    2007-02-01

    Gold is a highly valuable metal that can concentrate in iron-rich exogenetic horizons such as laterites. An improved knowledge of the retention mechanisms of gold onto highly reactive soil components such as iron oxy-hydroxides is therefore needed to better understand and predict the geochemical behavior of this element. In this study, we use EXAFS information and titration experiments to provide a realistic thermochemical description of the sorption of trivalent gold onto iron oxy-hydroxides. Analysis of Au LIII-edge XAFS spectra shows that aqueous Au(III) adsorbs from chloride solutions onto goethite surfaces as inner-sphere square-planar complexes (Au(III)(OH,Cl)4), with dominantly OH ligands at pH > 6 and mixed OH/Cl ligands at lower pH values. In combination with these spectroscopic results, Reverse Monte Carlo simulations were used to constraint the possible sorption sites on the surface of goethite. Based on this structural information, we calculated sorption isotherms of Au(III) on Fe oxy-hydroxides surfaces, using the CD-MUSIC (Charge Distribution — MUlti SIte Complexation) model. The various Au(III)-sorbed species were identified as a function of pH, and the results of these EXAFS+CD-MUSIC models are compared with titration experiments. The overall good agreement between the predicted and measured structural models shows the potential of this combined approach to better model sorption processes of transition elements onto highly reactive solid surfaces such as goethite and ferrihydrite.

  1. An integrated power generation system combining solid oxide fuel cell and oxy-fuel combustion for high performance and CO2 capture

    An integrated power generation system combining solid oxide fuel cell (SOFC) and oxy-fuel combustion technology is proposed. The system is revised from a pressurized SOFC-gas turbine hybrid system to capture CO2 almost completely while maintaining high efficiency. The system consists of SOFC, gas turbine, oxy-combustion bottoming cycle, and CO2 capture and compression process. An ion transport membrane (ITM) is used to separate oxygen from the cathode exit air. The fuel cell operates at an elevated pressure to facilitate the use of the ITM, which requires high pressure and temperature. The remaining fuel at the SOFC anode exit is completely burned with oxygen at the oxy-combustor. Almost all of the CO2 generated during the reforming process of the SOFC and at the oxy-fuel combustor is extracted from the condenser of the oxy-combustion cycle. The oxygen-depleted high pressure air from the SOFC cathode expands at the gas turbine. Therefore, the expander of the oxy-combustion cycle and the gas turbine provides additional power output. The two major design variables (steam expander inlet temperature and condenser pressure) of the oxy-fuel combustion system are determined through parametric analysis. There exists an optimal condenser pressure (below atmospheric pressure) in terms of global energy efficiency considering both the system power output and CO2 compression power consumption. It was shown that the integrated system can be designed to have almost equivalent system efficiency as the simple SOFC-gas turbine hybrid system. With the voltage of 0.752 V at the SOFC operating at 900 oC and 8 bar, system efficiency over 69.2% is predicted. Efficiency penalty due to the CO2 capture and compression up to 150 bar is around 6.1%.

  2. Two-dimensional flame temperature and emissivity measurements of pulverized oxy-coal flames

    Highlights: ► Two emissivity models were investigated for use with pyrometry in coal flames. ► The oxy-fired coal produced flame temperatures in excess of 2400 K. ► The H. B. Model produced an average temperature 9% lower and emissivity 81% lower. ► Addition of CO2 to the secondary air decreased the flame temperature by over 200 K. ► The measured and calculated decrease in flame temperature with CO2 addition were similar. -- Abstract: A broadband, RGB, two-color pyrometry technique for measuring the flame temperature and total emissivity of a two-dimensional image of a coal flame has been developed and used on an oxy-coal flame. The method uses a single, relatively inexpensive, RGB, digital camera. The camera software permits the light intensities of the red, green, and blue light collected for each pixel to be recorded separately. The response of each pixel was calibrated for each color using a blackbody radiating cavity and a monochrometer, which enabled an absolute, broadband emission measurement. The image obtained by the camera was processed to produce a temperature and total emissivity for each pixel. Two spectral emissivity models were explored for use in determining the temperature and emissivity: a Gray model and Hottel and Broughton’s soot emissivity model. Significant differences of 7.1% in average temperature and 24.2% in average emissivity were found. While neither model is ideal for the entire coal flame, the Hottel and Broughton model was selected for future image processing because the images and analysis suggested soot was the more dominant emitter for most of the image. Images were obtained in a 150 kWth, pulverized-coal reactor at two different mixture oxidizer ratios of O2/CO2. The addition of CO2 decreased the average flame temperature from 2183 K to 2022 K and reduced the average emissivity from 0.59 to 0.13. The increase in CO2 lowered the temperature by increasing the dilution. The increased flow rate caused increased mixing

  3. Amination of oxy acids in aqueous solution by gamma-irradiation

    Alanin, β-alanine, glicine, and aspartic, α-amino-n-butyric, and γ-amino-n-butyric acids were obtained by γ-irradiation of aqueous ammonia solutions of lactic, β-oxypropionic, glycolic, malic, α-oxybutyric, and γ-oxybutyric acids, respectively. The yields of amino acids were examined for functions of radiation dose (0.75 - 3.55Mrad), concentrations of oxy acid (0.01 - 0.1M) and ammonia (0.1 - 15M), and substances added as radical (potassium iodide), and hydrated electron (nitrous oxide) scavengers. The maximum G-values were 0.6 for alanine in a solution of 0.1M lactic acid-4M ammonia and some nitrous oxide and 1.14 for β-alanine in a solution of 0.1M β-oxypropionic acid and 0.7M ammonia. The yield of alanine increased with increased concentrations of lactic acid and ammonia due to saturation of nitrous oxide but decreased when potassium iodide (0.03M) was added. The yield of β-alanine showed a maximum increase at ca. 0.7M ammonia and decreased when potassium iodide and nitrous oxide were added. Serine was obtained from G = 0.002 in a solution of β-oxypropionic acid and increased to G = 0.058 due to saturation of nitrous oxide. The manner of chemical amination due to radiation was studied from the above results. In general, oxy acids from which hydrogen has been abstracted by an H or OH radical react with ammonia to form amino acids. The effect of ammonia concentration on the yield of amino acids demonstrates that the NH2 radical abstracts the α-hydrogen of lactic acid but does not react with the β-hydrogen of β-oxypropionic acid. The effect of nitrous oxide indicates that hydrated electrons interfere with alanine formation, contribute to β-alanine formation, react with the carboxyl group of lactic acids to form lactamide, and abstract the β-hydroxyl group of β-oxypropionic acids to form β-alanine. (Bell, E.)

  4. Radiation and convective heat transfer, and burnout in oxy-coal combustion

    J.P. Smart; P. O' Nions; G.S. Riley [RWE npower, Swindon (United Kingdom)

    2010-09-15

    Measurements of radiative and convective heat transfer, and carbon-in-ash have been taken on the RWEn 0.5 MWth combustion test facility (CTF) firing two different coals under oxy-fuel firing conditions. The two coals fired were a Russian Coal and a South African Coal. Recycle ratios were varied within the range of 65-75% dependent on coal. Furnace exit O{sub 2} values were maintained at 3% and 6% for the majority of tests. Air firing tests were also performed to generate baseline data. The work gives a comprehensive insight into the effect of oxy-fuel combustion on both radiative and convective heat transfer, and carbon-in-ash compared to air under dry simulated recycle conditions. Results have shown peak radiative heat flux values are inversely related to the recycle ratio for the two coals studied. Conversely, the convective heat flux values increase with increasing recycle ratio. It was also observed that the axial position of the peak in radiative heat flux moves downstream away from the burner as recycle ratio is increased. A 'working range' of recycle ratios exists where both the radiative and convective heat fluxes are comparable with air. Carbon-in-ash (CIA) was measured for selected conditions. For air firing of Russian Coal, the CIA for follows and expected trend with CIA decreasing with increasing furnace exit O{sub 2}. The CIA data for the two recycle ratios of 72% and 68% for the same coal show that the CIA values are lower than for air firing for corresponding furnace exit O{sub 2} levels and vary little with the value of furnace exit O{sub 2}. CIA measurements were taken for the South African Coal for a range of recycle ratios at 3% and 6% furnace exit O{sub 2} levels. Results indicate that the CIA values are lower for higher furnace exit O{sub 2}. 32 refs., 11 figs., 1 tab.

  5. Staged, High-Pressure Oxy-Combustion Technology: Development and Scale-Up

    Axelbaum, Richard; Xia, Fei; Gopan, Akshay; Kumfer, Benjamin

    2014-09-30

    Washington University in St. Louis and its project partners are developing a unique pressurized oxy-combustion process that aims to improve efficiency and costs by reducing the recycling of flue gas to near zero. Normally, in the absence of recycled flue gas or another inert gas, combustion of fuel and oxygen results in a dramatic increase in temperature of the combustion products and radiant energy, as compared to combustion in air. High heat flux to the boiler tubes may result in a tube surface temperatures that exceed safe operating limits. In the Staged Pressurized Oxy-Combustion (SPOC) process, this problem is addressed by staging the delivery of fuel and by novel combustion design that allows control of heat flux. In addition, the main mode of heat transfer to the steam cycle is by radiation, as opposed to convection. Therefore, the requirement for recycling large amounts of flue gas, for temperature control or to improve convective heat transfer, is eliminated, resulting in a reduction in auxiliary loads. The following report contains a detailed summary of scientific findings and accomplishments for the period of Oct. 1, 2013 to Sept 30, 2014. Results of ASPEN process and CFD modelling activities aimed at improving the SPOC process and boiler design are presented. The effects of combustion pressure and fuel moisture on the plant efficiency are discussed. Combustor pressure is found to have only a minor impact beyond 16 bar. For fuels with moisture content greater than approx 30%, e.g. coal/water slurries, the amount of latent heat of condensation exceeds that which can be utilized in the steam cycle and plant efficiency is reduced significantly. An improved boiler design is presented that achieves a more uniform heat flux profile. In addition, a fundamental study of radiation in high-temperature, high-pressure, particle-laden flows is summarized which provides a more complete understanding of heat transfer in these unusual conditions and to allow for

  6. Tantalum (oxy)nitrides: Preparation, characterisation and enhancement of photo-Fenton-like degradation of atrazine under visible light

    Du, Yingxun, E-mail: yxdu@niglas.ac.cn [Nanjing Institute of Geography and Limnology, State Key Laboratory of Lake Science and Environment, Chinese Academy of Sciences, Nanjing 210008 (China); Zhao, Lu; Su, Yaling [Nanjing Institute of Geography and Limnology, State Key Laboratory of Lake Science and Environment, Chinese Academy of Sciences, Nanjing 210008 (China)

    2011-11-15

    Highlights: {yields} The photocatalytic activity of TaON for Fe{sup 3+} reduction is higher than that of Ta{sub 3}N{sub 5}. {yields} Atrazine degradation was accelerated significantly by tantalum (oxy)nitrides sample. {yields} The regenerated catalyst displays considerably stable performance for atrazine degradation. - Abstract: Tantalum (oxy)nitrides were prepared by the nitridation of Ta{sub 2}O{sub 5} and were added to a photo-Fenton-like system to enhance Fe{sup 3+} reduction and atrazine degradation under visible light. The samples were characterized by XRD, XPS, DRS and BET analyses. XPS analysis showed that the nitrogen content of the tantalum (oxy)nitride samples increased noticeably with the nitridation temperature and nitridation time but slightly with the flow rate of NH{sub 3}. XRD results showed Ta{sub 2}O{sub 5} was first converted to TaON and then to Ta{sub 3}N{sub 5} when the nitridation temperature increased. DRS analysis showed that the sample obtained at 800 {sup o}C displayed the strongest absorption of visible light. However, the ability of the tantalum (oxy)nitrides to reduce Fe{sup 3+} did not increase continuously with the nitrogen content. Sample 7 (700 {sup o}C, Q{sub NH{sub 3}}=0.3L/min, 6 h) showed the highest level of photocatalytic activity for Fe{sup 3+} reduction. This is because the photocatalytic activity of TaON for Fe{sup 3+} reduction is higher than that of Ta{sub 3}N{sub 5}. And a slight synergetic effect was observed between TaON and Ta{sub 3}N{sub 5}. With the addition of sample 7, H{sub 2}O{sub 2} decomposition and atrazine degradation were significantly accelerated in a photo-Fenton-like system under visible light. The regenerated tantalum (oxy)nitrides catalyst displayed considerably stable performance for atrazine degradation.

  7. Laboratory Investigations of the High Temperature Corrosion of Various Materials in Simulated oxy-fuel and Conventional Coal Firing

    Laboratory exposures in horizontal tube furnaces were conducted to test various materials for corrosion resistance in simulated oxy-fuel firing and conventional coal firing environments. Two different exposures were done at 630 C for 672 hours. The reaction atmosphere, consisting of CO2, H2O, O2, N2 and SO2, was mixed to resemble that of oxy-fuel firing in the first exposure and that of conventional coal firing in the second exposure (N2 was added during the second exposure only). Four different materials were tested in the first exposure; Sanicro 63, Alloy 800HT, 304L and 304HCu. In the second exposure four different materials were tested; 304L, Alloy 800HT, Kanthal APMT and NiCrAl. Apart from cleaned sample coupons, some samples pre-exposed in a test rig under oxy-fuel conditions with lignite as fuel and some pre-exposed with bituminous coal as fuel were investigated in the first exposure. In the second exposure some samples were pre-exposed in a rig under conventional firing conditions with lignite as fuel. The corrosion attack on the investigated samples was analysed by gravimetry, x-ray diffraction (XRD) and scanning electron microscopy (SEM) with energy dispersive x-ray (EDX). The SEM/EDX analysis was made on both the sample envelope and metallographic cross sections of the samples. The results show that there is small difference in the corrosion attack between the two environments. There was also little difference in oxide morphology and composition between cleaned samples and pre-exposed samples of the same material. The austenitic chromia former 304HCu suffered the most extensive corrosion attack in the oxy-fuel environment. In the conventional air firing environment 304L showed the highest mass gain. Chromia formers with higher chromium concentrations performed better, especially the super austenitic Alloy 800HT, with its high chromium concentration, formed a thin and protective corundum type oxide. The nickel based Sanicro 63 showed very low corrosion

  8. Laboratory Investigations of the High Temperature Corrosion of Various Materials in Simulated oxy-fuel and Conventional Coal Firing

    Folkeson, N.; Pettersson, J.; Svensson, J.E. [Chalmers Univ. of Technology (Sweden); Hjornhede, A. [Vattenfall Power Consultant AB (Sweden); Montgomery, M. [Vattenfall Heat Nordic/DTU Mekanik (Denmark); Bjurman, M. [Vattenfall Research and Development AB (Sweden)

    2009-07-01

    Laboratory exposures in horizontal tube furnaces were conducted to test various materials for corrosion resistance in simulated oxy-fuel firing and conventional coal firing environments. Two different exposures were done at 630 C for 672 hours. The reaction atmosphere, consisting of CO{sub 2}, H{sub 2}O, O{sub 2}, N{sub 2} and SO{sub 2}, was mixed to resemble that of oxy-fuel firing in the first exposure and that of conventional coal firing in the second exposure (N{sub 2} was added during the second exposure only). Four different materials were tested in the first exposure; Sanicro 63, Alloy 800HT, 304L and 304HCu. In the second exposure four different materials were tested; 304L, Alloy 800HT, Kanthal APMT and NiCrAl. Apart from cleaned sample coupons, some samples pre-exposed in a test rig under oxy-fuel conditions with lignite as fuel and some pre-exposed with bituminous coal as fuel were investigated in the first exposure. In the second exposure some samples were pre-exposed in a rig under conventional firing conditions with lignite as fuel. The corrosion attack on the investigated samples was analysed by gravimetry, x-ray diffraction (XRD) and scanning electron microscopy (SEM) with energy dispersive x-ray (EDX). The SEM/EDX analysis was made on both the sample envelope and metallographic cross sections of the samples. The results show that there is small difference in the corrosion attack between the two environments. There was also little difference in oxide morphology and composition between cleaned samples and pre-exposed samples of the same material. The austenitic chromia former 304HCu suffered the most extensive corrosion attack in the oxy-fuel environment. In the conventional air firing environment 304L showed the highest mass gain. Chromia formers with higher chromium concentrations performed better, especially the super austenitic Alloy 800HT, with its high chromium concentration, formed a thin and protective corundum type oxide. The nickel based

  9. Development of a biomass torrefaction process integrated with oxy-fuel combustion.

    Tran, Khanh-Quang; Trinh, Trung Ngoc; Bach, Quang-Vu

    2016-01-01

    Torrefaction of forest residues was studied under conditions relevant to oxy-fuel combustion flue gases. The results showed that the torrefaction in CO2 had a lower solid mass yield (81.36%) than that (83.06%) in N2. Addition of steam into CO2 (CO2/H2O=1/0.7 mole/mole) resulted in a higher mass yield (83.30%) compared to 81.36% in CO2. The energy yield was consistently increased from 79.17% to 84.12% or 88.32% for the torrefaction in N2, CO2, or the CO2 and steam mixture, respectively. On the other hand, additions of O2 into the mixture of steam and CO2 led to reductions in both mass yield (from 83.30% to 82.57% or 76.44%) and energy yield (from 88.32% to 84.65% or 79.16%, for the torrefaction in steam and CO2 without O2, with 5% v/v, or 10% v/v of O2, respectively). PMID:26362464

  10. Radiation-induced chemistry of poly(4-[(tert-butoxycarbonyl)oxy]styrene-co-sulfur dioxide)

    Copolymers of 4-[(tert-butoxycarbonyl)oxy]styrene (TBS) and sulfur dioxide (SO2) have been found to act as sensitive X-ray (λ = 14 angstrom) single-component, chemically amplified, aqueous-base-soluble positive-acting resists. The X-ray response of these materials was a function of copolymer composition and independent of molecular weight. It was observed that increasing the SO2 content enhanced the resist sensitivity. Initial investigation into the radiation-induced reaction mechanism provided evidence that acid formation occurs via polymer main-chain scission. It is proposed that at the scission sites radical species are produced which in turn are responsible for the formation of the acid moieties. Heat treatment of resist films after exposure converted copolymers to poly(4-hydroxystyrene sulfone) and permitted exposed film areas to be developed in an aqueous base solution. Preliminary lithographic evaluation has resolved 0.5-μm line and space patterns in 0.65-μm-thick 1.75/1 TBS/SO2 resist films using an X-ray dose of 10 mJ/cm2. No change in X-ray dose was required to resolve the same width feature in the same resist having a film thickness of 1.0 μm

  11. Radiation-induced chemistry of poly(4-[(tert-butoxycarbonyl)oxy]styrene-co-sulfur dioxide)

    Novembre, A.E.; Tai, W.W.; Kometani, J.M.; Hanson, J.E.; Nalamasu, O.; Taylor, G.N.; Reichmanis, E.; Thompson, L.F. (AT T Bell Labs., Murray Hill, NJ (United States))

    Copolymers of 4-[(tert-butoxycarbonyl)oxy]styrene (TBS) and sulfur dioxide (SO[sub 2]) have been found to act as sensitive X-ray ([lambda] = 14 [angstrom]) single-component, chemically amplified, aqueous-base-soluble positive-acting resists. The X-ray response of these materials was a function of copolymer composition and independent of molecular weight. It was observed that increasing the SO[sub 2] content enhanced the resist sensitivity. Initial investigation into the radiation-induced reaction mechanism provided evidence that acid formation occurs via polymer main-chain scission. It is proposed that at the scission sites radical species are produced which in turn are responsible for the formation of the acid moieties. Heat treatment of resist films after exposure converted copolymers to poly(4-hydroxystyrene sulfone) and permitted exposed film areas to be developed in an aqueous base solution. Preliminary lithographic evaluation has resolved 0.5-[mu]m line and space patterns in 0.65-[mu]m-thick 1.75/1 TBS/SO[sub 2] resist films using an X-ray dose of 10 mJ/cm[sup 2]. No change in X-ray dose was required to resolve the same width feature in the same resist having a film thickness of 1.0 [mu]m.

  12. Comparison of Fuel-Nox Formation Characteristics in Conventional Air and Oxy fuel Combustion Conditions

    Nitric oxide (NOx) formation characteristics in non-premixed diffusion flames of methane fuels have been investigated experimentally and numerically by adding 10% ammonia to the fuel stream, according to the variation of the oxygen ratio in the oxidizer with oxygen/carbon dioxide and oxygen/nitrogen mixtures. In an experiment of co flow jet flames, in the case of an oxidizer with oxygen/carbon dioxide, the NOx emission increased slightly as the oxygen ratio increased. On the other hand, in case of an oxygen/nitrogen oxidizer, the NOx emission was the maximum at an oxygen ratio of 0.7, and it exhibited non-monotonic behavior according to the oxygen ratio. Consequently, the NOx emission in the condition of oxy fuel combustion was overestimated as compared to that in the condition of conventional air combustion. To elucidate the characteristics of NOx formation for various oxidizer compositions, 1a and 2a numerical simulations have been conducted by adopting one kinetic mechanism. The result of 2 simulation for an oxidizer with oxygen/nitrogen well predicted the trend of experimentally measured NOx emissions

  13. NO formation during oxy-fuel combustion of coal and biomass chars

    Zhao, Ke; Jensen, Anker Degn; Glarborg, Peter

    2014-01-01

    pronounced at 850 °C than at 1050-1150 °C. The present work indicates that the effect of CO2 on NO formation in oxy-fuel combustion in fluidized beds can partly be attributed to heterogeneous reactions, whereas for high-temperature pulverized fuel combustion, CO2 mainly affects the volatile chemistry. © 2014......The yields of NO from combustion of bituminous coal, lignite, and biomass chars were investigated in O2/N2 and O2/CO 2 atmospheres. The experiments were performed in a laboratory-scale fixed-bed reactor in the temperature range of 850-1150 °C. To minimize thermal deactivation during char...... preparation, the chars were generated by in situ pyrolysis at the reaction temperature. The NO yield clearly decreased and the CO yield increased when the atmosphere was altered from O2/N 2 to O2/CO2 at 850 °C, but only small differences in NO and CO yields were observed between the two atmospheres at 1050...

  14. Nanostructured titania/hydroxyapatite composite coatings deposited by high velocity oxy-fuel (HVOF) spraying

    Pure nanostructured titania (TiO2) and blends with 10 and 20 wt% hydroxyapatite (HA) powders were sprayed onto Ti-6Al-4V substrates using a high velocity oxy-fuel (HVOF) system. The feedstock powders employed in this work were engineered to exhibit similar particle size distributions in order to generate similar values of particle temperature and velocity in the spray jet. By achieving these characteristics it was assumed that the differences in coating properties and microstructures produced in this study were mainly related to the nature and composition of the feedstock powders, rather than to the spraying parameters or in-flight particle characteristics. The microstructure, porosity, roughness, Vickers hardness and bond strength (ASTM C633) of these coatings were analyzed and evaluated. X-ray diffraction (XRD) patterns showed that no detectable chemical reaction occurred between the nanostructured TiO2 and HA phases during the spray process. Due to the poor mechanical performance of HA, its addition decreased the bond strength and hardness values of the coatings, especially when the content of HA was 20 wt%; however, the bond strength values were still much superior to those of HA thermally sprayed coatings. The addition of HA to nanostructured titania for producing HVOF-sprayed coatings could be very interesting for biomedical applications due to the combination of the good mechanical performance and chemical stability of nanostructured titania and a bioactive phase (HA) that can enhance the bio-performance of the coating

  15. Oxy-fuel combustion technology for coal-fired power generation

    The awareness of the increase in greenhouse gas emissions has resulted in the development of new technologies with lower emissions and technologies that can accommodate capture and sequestration of carbon dioxide. For existing coal-fired combustion plants there are two main options for CO2 capture: removal of nitrogen from flue gases or removal of nitrogen from air before combustion to obtain a gas stream ready for geo-sequestration. In oxy-fuel combustion, fuel is combusted in pure oxygen rather than air. This technology recycles flue gas back into the furnace to control temperature and makeup the volume of the missing N2 to ensure there is sufficient gas to maintain the temperature and heat flux profiles in the boiler. A further advantage of the technology revealed in pilot-scale tests is substantially reduced NOx emissions. For coal-fired combustion, the technology was suggested in the eighties, however, recent developments have led to a renewed interest in the technology. This paper provides a comprehensive review of research that has been undertaken, gives the status of the technology development and assessments providing comparisons with other power generation options, and suggests research needs. (author)

  16. A novel hybrid oxy-fuel power cycle utilizing solar thermal energy

    An advanced oxy-fuel hybrid power system (AHPS) is proposed in this paper. Solar thermal energy is used in the AHPS to produce saturated steam as the working fluid, and natural gas is internally combusted with pure oxygen. It is in configuration close to the zero emission Graz cycle. The thermodynamic characteristics at design conditions of the AHPS are analyzed using the advanced process simulator Aspen Plus. The corresponding exergy loss analyses are also carried out to gain understanding of the loss distribution. The results are given in detail. The solar thermal hybrid H2O turbine power generation system (STHS) is evaluated in this study as the reference. The comparison results demonstrate that the proposed cycle has notable advantages in thermodynamic performances. For example, the net fuel-to-electricity efficiency of the AHPS is 95.90%, which is 21.61 percentage points higher than that of the STHS. The exergy efficiency (based on the exergy input of fuel and solar thermal energy without radiation) of the AHPS is 55.88%, which is 2.13 percentage points higher than that of the STHS

  17. Microstructure and photocatalytic performance of high velocity oxy-fuel sprayed TiO2 coatings

    Titanium dioxide photocatalytic coatings were deposited through high velocity oxy-fuel (HVOF) spraying agglomerate anatase powder. Different spray parameters (e.g. flow of fuel gas) were utilized with the aim to reveal their influence on microstructure and photocatalytic performance of the HVOF titania coatings. The microstructure of the coatings was characterized using X-ray diffraction and scanning electron microscope. The photocatalytic performance of the coatings was evaluated through analyzing photocatalytical degradation of phenol using an ultraviolet spectrometry. Results showed that the phase compositions of the titania coatings were significantly influenced by melting state of the sprayed particles, which was influenced mainly by fuel gas flow. The HVOF TiO2 coating with up to 70% anatase phase can be obtained through assuring a limited melting state of the titania powder during the coating deposition. A content of 40% of the anatase phase was obtained in the coating deposited from well-melted particles. Furthermore, the present HVOF titania coatings showed promising effect in photocatalytically degrading phenol in the solution. It was found that the complete mineralization of phenol was controlled by the degradation of the intermediates resulting from the decomposition of phenol. It was also noted that the presence of certain rutile phase in the HVOF titania coatings enhanced their photocatalytic performance

  18. In vitro performance of ceramic coatings obtained by high velocity oxy-fuel spray.

    Melero, H; Garcia-Giralt, N; Fernández, J; Díez-Pérez, A; Guilemany, J M

    2014-01-01

    Hydroxyapatite coatings obtained by plasma-spraying have been used for many years to improve biological performance of bone implants, but several studies have drawn attention to the problems arising from high temperatures and the lack of mechanical properties. In this study, plasma-spraying is substituted by high velocity oxy-fuel (HVOF) spray, with lower temperatures reached, and TiO2 is added in low amounts to hydroxyapatite in order to improve the mechanical properties. Four conditions have been tested to evaluate which are those with better biological properties. Viability and proliferation tests, as well as differentiation assays and morphology observation, are performed with human osteoblast cultures onto the studied coatings. The hydroxyapatite-TiO2 coatings maintain good cell viability and proliferation, especially the cases with higher amorphous phase amount and specific surface, and promote excellent differentiation, with a higher ALP amount for these cases than for polystyrene controls. Observation by SEM corroborates this excellent behaviour. In conclusion, these coatings are a good alternative to those used industrially, and an interesting issue would be improving biological behaviour of the worst cases, which in turn show the better mechanical properties. PMID:25201392

  19. Analysis of the cumulative exergy consumption of an integrated oxy-fuel combustion power plant

    Ziębik, Andrzej; Gładysz, Paweł

    2013-09-01

    In order to analyze the cumulative exergy consumption of an integrated oxy-fuel combustion power plant the method of balance equations was applied based on the principle that the cumulative exergy consumption charging the products of this process equals the sum of cumulative exergy consumption charging the substrates. The set of balance equations of the cumulative exergy consumption bases on the `input-output method' of the direct energy consumption. In the structure of the balance we distinguished main products (e.g. electricity), by-products (e.g. nitrogen) and external supplies (fuels). In the balance model of cumulative exergy consumption it has been assumed that the cumulative exergy consumption charging the supplies from outside is a quantity known a priori resulting from the analysis of cumulative exergy consumption concerning the economy of the whole country. The byproducts are charged by the cumulative exergy consumption resulting from the principle of a replaced process. The cumulative exergy consumption of the main products is the final quantity.

  20. Residual Stresses in High-Velocity Oxy-Fuel Metallic Coatings

    X-ray based residual stress measurements were made on type 316 stainless steel and Fe3A1 coatings that were high-velocity oxy-fuel (HVOF) sprayed onto low-carbon and stainless steel substrates. Nominal coating thicknesses varied from 250 to 1500 mm. The effect of HVOF spray particle velocity on residual stress and deposition efficiency was assessed by preparing coatings at three different torch chamber pressures. The effect of substrate thickness on residual stress was determined by spraying coatings onto thick (6.4 mm) and thin (1.4 mm) substrates. Residual stresses were compressive for both coating materials and increased in magnitude with spray velocity. For coatings applied to thick substrates, near-surface residual stresses were essentially constant with increasing coating thickness. Difference in thermal expansion coefficient between low-carbon and stainless steels led to a 180 MPa difference in residual stress for Fe3A1 coatings. Deposition efficiency for both materials is maximized at an intermediate (∼600 m/s) velocity. Considerations for X-ray measurement of residual stresses in HVOF coatings are also presented

  1. Two novel oxy-fuel power cycles integrated with natural gas reforming and CO2 capture

    Two novel system configurations were proposed for oxy-fuel natural gas turbine systems with integrated steam reforming and CO2 capture and separation. The steam reforming heat is obtained from the available turbine exhaust heat, and the produced syngas is used as fuel with oxygen as the oxidizer. Internal combustion is used, which allows a very high heat input temperature. Moreover, the turbine working fluid can expand down to a vacuum, producing an overall high-pressure ratio. Particular attention was focused on the integration of the turbine exhaust heat recovery with both reforming and steam generation processes, in ways that reduce the heat transfer-related exergy destruction. The systems were thermodynamically simulated, predicting a net energy efficiency of 50-52% (with consideration of the energy needed for oxygen separation), which is higher than the Graz cycle energy efficiency by more than 2 percentage points. The improvement is attributed primarily to a decrease of the exergy change in the combustion and steam generation processes that these novel systems offer. The systems can attain a nearly 100% CO2 capture

  2. Comparison of Fuel-Nox Formation Characteristics in Conventional Air and Oxy fuel Combustion Conditions

    Woo, Mino [Kyungwon Engineering and Communication, Seongnam (Korea, Republic of); Park, Kweon Ha [Korea Maritime Univ., Busan (Korea, Republic of); Choi, Byung Chul [Korean Register of Shipping, Busan (Korea, Republic of)

    2013-05-15

    Nitric oxide (NO{sub x}) formation characteristics in non-premixed diffusion flames of methane fuels have been investigated experimentally and numerically by adding 10% ammonia to the fuel stream, according to the variation of the oxygen ratio in the oxidizer with oxygen/carbon dioxide and oxygen/nitrogen mixtures. In an experiment of co flow jet flames, in the case of an oxidizer with oxygen/carbon dioxide, the NO{sub x} emission increased slightly as the oxygen ratio increased. On the other hand, in case of an oxygen/nitrogen oxidizer, the NO{sub x} emission was the maximum at an oxygen ratio of 0.7, and it exhibited non-monotonic behavior according to the oxygen ratio. Consequently, the NO{sub x} emission in the condition of oxy fuel combustion was overestimated as compared to that in the condition of conventional air combustion. To elucidate the characteristics of NO{sub x} formation for various oxidizer compositions, 1a and 2a numerical simulations have been conducted by adopting one kinetic mechanism. The result of 2 simulation for an oxidizer with oxygen/nitrogen well predicted the trend of experimentally measured NO{sub x} emissions.

  3. Zero Liquid Discharge (ZLD) System for Flue-Gas Derived Water From Oxy-Combustion Process

    Sivaram Harendra; Danylo Oryshchyn; Thomas Ochs; Stephen J. Gerdemann; John Clark

    2011-10-16

    Researchers at the National Energy Technology Laboratory (NETL) located in Albany, Oregon, have patented a process - Integrated Pollutant Removal (IPR) that uses off-the-shelf technology to produce a sequestration ready CO{sub 2} stream from an oxy-combustion power plant. Capturing CO{sub 2} from fossil-fuel combustion generates a significant water product which can be tapped for use in the power plant and its peripherals. Water condensed in the IPR{reg_sign} process may contain fly ash particles, sodium (from pH control), and sulfur species, as well as heavy metals, cations and anions. NETL is developing a treatment approach for zero liquid discharge while maximizing available heat from IPR. Current treatment-process steps being studied are flocculation/coagulation, for removal of cations and fine particles, and reverse osmosis, for anion removal as well as for scavenging the remaining cations. After reverse osmosis process steps, thermal evaporation and crystallization steps will be carried out in order to build the whole zero liquid discharge (ZLD) system for flue-gas condensed wastewater. Gypsum is the major product from crystallization process. Fast, in-line treatment of water for re-use in IPR seems to be one practical step for minimizing water treatment requirements for CO{sub 2} capture. The results obtained from above experiments are being used to build water treatment models.

  4. Energy transfer and frequency upconversion in Er3+-Yb3+ codoped oxy-fluoro-tungstosilicate glasses

    JIE Guantao; ZHAO Gaoling; WANG Jianxun; HAN Gaorong

    2012-01-01

    Er3+-Yb3+ codoped oxy-fluoro-tungstosilicate glasses with infrared-to-visible frequency upconversion luminescence were prepared by melting quenching in air.The effects of Er3+ doping on the optical properties of the samples were measured by means of techniques such as optical absorption spectra and photoluninescence spectra.The results showed that intense green and red signals centered at 546 and 665 nm,corresponding to the 4S3/2→4I15/2 and 4F9/2→4I15/2 transitions of Er3+ by a multiphoton stepwise phonon-assisted excited-state absorption process,respectively,were simultaneously observed by exciting the samples with a diode laser operating at 980 nm at room temperature.The upconversion process was found very sensitive to Err3- content at a constant Yb2O3 content of 5 mol.%.With the increase of Er3+ content from 0.5% to 1.5%,the upconversion intensity increased gradually.Further increasing of Er3+ content to 3.0% resulted in a significant fluorescence quenching.Moreover,the possible upconversion mechanisms were discussed based on the energy-matching conditions and the quadratic dependence on excitation power.

  5. Oxy-acetylene driven laboratory scale shock tubes for studying blast wave effects

    Courtney, Michael

    2011-01-01

    Instrumentation is needed to produce realistic blast waves in a laboratory setting. This paper describes the development and characterization of oxy-acetylene driven, laboratory scale shock tubes for use in studying blast injury, candidate armor materials, and material properties at blast loading rates. The pressure-time profiles show a true shock front and exponential decay characteristic of blast waves and have relevant durations. The modular design includes shock tube diameters of 27 mm and 41 mm, and a selection of peak pressures from 204 kPa to 920 kPa can be produced by selection of the driver section diameter and placement of the test sample. Characterization studies of several driver/driven section combinations showed consistent results, with peak pressures having 0.8 - 6.9 percent uncertainty in the mean. This shock tube design provides a more realistic blast profile than current air-driven shock tubes. In addition, operation does not require specialized personnel or facilities like most blast-driven...

  6. Analysis of Particle Behavior in High-Velocity Oxy-Fuel Thermal Spraying Process

    Hiroshi Katanoda; Kazuyasu Matsuo

    2003-01-01

    This paper analyzes the behavior of coating particle as well as the gas flow both of inside and outside the High-Velocity Oxy-Fuel (HVOF) thermal spraying gun by using quasi-one-dimensional analysis and numerical simulation. The HVOF gun in the present analysis is an axisymmetric convergent-divergent nozzle with the design Mach number of 2.0 followed by a straight passage called barrel. In the present analysis it is assumed that the influence of the particles injected in the gas flow is neglected, and the interaction between the particles is also neglected. The gas flow in the gun is assumed to be quasi-one-dimensional adiabatic flow. The velocity, temperature and density of gas in the jet discharged from the barrel exit are predicted by solving Navier-Stokes equations numerically. The particle equation of motion is numerically integrated using three-step Runge-Kutta method. The drag coefficient of the particle is calculated by linear interpolation of the experimental data obtained in the past. Particle mean temperature is calculated by using Ranz and Marchalls' correlation for spherical particles. From the present analysis, the distributions of velocity and temperature of the coating particles flying inside and outside the HVOF gun are predicted.

  7. Crystal structure of [1,1':3',1''-ter-phenyl]-2',3,3''-tri-carb-oxy-lic acid.

    Decato, Daniel A; Berryman, Orion B

    2015-09-01

    The asymmetric unit of the title compound, C21H14O6, com-prises two symmetrically independent mol-ecules that form a locally centrosymmetric hydrogen-bonded dimer, with the planes of the corresponding carb-oxy-lic acid groups rotated by 15.8 (1) and 17.5 (1)° relative to those of the adjacent benzene rings. The crystal as a whole, however, exhibits a noncentrosymmetric packing, described by the polar space group Pca21. The dimers form layers along the ab plane, being inter-connected by hydrogen bonds involving the remaining carb-oxy-lic acid groups. The plane of the central carb-oxy-lic acid group forms dihedral angles of 62.5 (1) and 63.0 (1)° with those of the adjacent benzene rings and functions as a hydrogen-bond donor and acceptor. As a donor, it inter-connects adjacent layers, while as an acceptor it stabilizes the packing within the layers. The 'distal' carb-oxy-lic acid groups are nearly coplanar with the planes of the adjacent benzene rings, forming dihedral angles of 1.8 (1) and 7.1 (1)°. These groups also form intra- and inter-layer hydrogen bonds, but with 'reversed' functionality, as compared with the central carb-oxy-lic acid groups. PMID:26396894

  8. Crystal structures of the potassium and rubidium salts of (3,5-di­chloro­phen­oxy)acetic acid: two isotypic coordination polymers

    Smith, Graham

    2015-01-01

    The two-dimensional coordination polymeric structures of the hydrated potassium and rubidium salts of (3,5-di­chloro­phen­oxy)acetic acid (3,5-D), namely, poly[μ-aqua-bis­[μ3-2-(3,5-di­chloro­phen­oxy)acetato]­dipotassium], [K2(C8H5Cl2O3)2(H2O)] n , and poly[μ-aqua-bis­[μ3-2-(3,5-di­chloro­phen­oxy)acetato]­dirubidium], [Rb2(C8H5Cl2O3)2(H2O)] n , respectively, have been determined and are described. The two compounds are isotypic and the polymeric structure is based on centrosymmetric dinucle...

  9. (2,9-Dieth­oxy-1,10-phenanthroline-κ2 N,N′)bis­(thio­cyanato-κN)cobalt(II)

    Zheng, Xian-Fu; Su, Hui; Zhou, Zhan-Fang; Kou, Chun-Hong; Niu, Cao-Yuan

    2008-01-01

    In the title complex, [Co(NCS)2(C16H16N2O2)], the CoII ion is coordinated by two N atoms from one 2,9-dieth­oxy-1,10-phenanthroline ligand and two N atoms from two different thio­cyanate ligands in a distorted tetra­hedral environment. The Co—N bonds involving the thio­cyanate ligands are significantly shorter than the other two Co—N bonds. The atoms of one of the eth­oxy groups are essentially coplanar with the phenanthroline ring [N=C—O—C = 178.8 (4)°], while the other eth­oxy group is slig...

  10. Diurnal and nocturnal measurements of PAH, nitro-PAH, and oxy-PAH compounds in atmospheric particulate matter of a sugar cane burning region

    Souza, Kely F.; Carvalho, Lilian R. F.; Allen, Andrew G.; Cardoso, Arnaldo A.

    2014-02-01

    Polycyclic aromatic hydrocarbons (PAHs), nitro-PAHs, and oxy-PAHs were studied in the atmospheric particulate matter of a subtropical rural region (São Paulo State, Brazil) affected by emissions from sugar cane burning. Diurnal and nocturnal samples were collected from May to June of 2010. In general, average PAH concentrations were significantly higher at night, suggesting that the compounds were predominantly emitted to the atmosphere during biomass burning (which was mainly performed at night). The maximum average PAH concentration was found for benzo[b]fluoranthene at night (2.9 ± 5.4 ng m-3). Among the nitro-PAH compounds, the highest average concentrations were obtained for 9-nitrophenanthrene in diurnal and nocturnal samples (1.5 ± 1.2 and 1.3 ± 2.1 ng m-3, respectively). In contrast to the PAH and nitro-PAH compounds, the oxy-PAHs could not be directly associated with sugar cane burning. The most abundant oxy-PAH compound was benzanthrone (1.6 ± 1.3 ng m-3) at night, followed by 9,10-anthraquinone (1.1 ± 0.9 ng m-3) and 9-fluorenone (0.4 ± 0.1 ng m-3) during the day. A correlation matrix was used to explore the origins of the different compounds. The data suggested that during the daytime, direct emissions (mainly in vehicle exhaust) contributed to the presence of PAHs, nitro-PAHs, and oxy-PAHs in air. Photochemical production also appeared to be a source of the majority of nitro-PAHs and oxy-PAHs, while photolysis could have contributed to removal of the nitro-PAHs during the daytime. At night, sugar cane burning emissions were the primary source of the PAHs and nitro-PAHs, with additional sources also contributing to the levels of oxy-PAHs in the atmosphere.

  11. Reprint of “Experiences in sulphur capture in a 30 MWth Circulating Fluidized Bed boiler under oxy-combustion conditions”

    CO2 and SO2 from fossil fuel combustion are contributors to greenhouse effect and acid rain respectively. Oxy-combustion technology produces a highly concentrated CO2 stream almost ready for capture. Circulating Fluidized Bed (CFB) boiler technology allows in-situ injection of calcium-based sorbents for efficient SO2 capture. CIUDEN's 30 MWth CFB boiler, supplied by Foster Wheeler and located at the Technology Development Centre for CO2 Capture and Transport (es.CO2) in Spain, is the first of its kind for executing test runs at large pilot scale under both air-combustion and oxy-combustion conditions. In this work, SO2 emissions under different scenarios have been evaluated. Variables such as limestone composition, Ca/S molar ratio and bed temperature among others have been considered along different test runs in both air-combustion and oxy-combustion conditions to analyse its influence on SO2 abatement. Fly and bottom ash, together with flue gas analysis have been carried-out. Desulphurization performance tests results are presented. - Highlights: • Sulphur capture efficiency (%) was higher in oxy-combustion compared to air-combustion in a 30 MW thermal CFB boiler using anthracite and limestone as sulphur sorbent. • For a Ca/S molar ratio higher than 2.6 there was barely any improvement on sulphur capture efficiency for both air-combustion and oxy-combustion conditions in a 30 MW thermal CFB boiler using anthracite and limestone as sulphur sorbent. • Optimum temperature for sulphur capture at a fixed Ca/S molar ratio is around 880–890 °C under oxy-combustion conditions and for anthracite coal with limestone as sorbent in a 30 MW thermal CFB boiler

  12. Numerical investigation of oxygen permeation and methane oxy-combustion in a stagnation flow ion transport membrane reactor

    In this work, a two-step oxy-combustion reaction kinetics model for methane-oxygen combustion is used to predict the oxy-combustion characteristics in the permeate side of the membrane. More accurate permeation rate characteristics inside this simple symmetric design ITM reactor is also expected using this model. New oxygen permeation model is introduced in this work for an LSCF-1991 ion transport membrane. The simulation of the oxygen permeation process across the membrane has been performed through series of visual C++ user defined function compiled and incorporated to FLUENT. The analysis of the permeation process has been conducted for separation only process (no reactions) using an inert gas (argon) as a sweep gas and a comparison has been done with cases of using CH4 plus CO2 as sweep gases. The effect of reactivity using the same sweep gases (CH4 plus CO2) is investigated by comparing the same cases with and without reactions in the permeate side. It was found that there are important parameters affecting the operation of ITM reactors like the inlet gases temperature, percentage of CH4 in the sweep gases mixture and the reactor geometry. Also, there are less important parameters like, feed and sweep volume flow rates, oxygen partial pressure in the feed side. - Highlights: • More accurate two-step methane oxy-combustion reaction kinetics model is introduced. • A new coefficients oxygen permeation equation model is introduced. • A detailed 2D study is presented to understand the performance of ITM reactors. • Using of CH4+CO2 as sweep gases is better than using argon for separation only process. • Chemical reactions have a great effect on enhancing the oxygen permeation flux

  13. A comparative evaluation of gray and non-gray radiation modeling strategies in oxy-coal combustion simulations

    Computational fluid dynamic simulations of oxy-coal combustion are demonstrated in a lab-scale furnace and full-scale boiler employing gray and non-gray formulations of recently proposed radiative property models for the gas-phase. The investigated scenarios included: air-firing, oxy-firing with dry and wet flue-gas recycle (FGR). The study confirms that the temperature and wall radiative flux profiles encountered during air firing can be replicated in both dry and wet FGR scenarios through an appropriate selection of (CO2 + H2O)/O2 molar ratios in the oxidizer stream. The computed temperature profiles were in reasonable agreement with the experimental measurements. In the lab-scale furnace, lower flame temperatures and smaller path lengths minimized the differences between the gray and non-gray model predictions. Within the full-scale boiler, large volume pockets were present where the radiation was dominated by the gas-phase. This combined with higher peak flame temperatures and longer path lengths resulted in: a 10% variation between the gray and non-gray radiative fluxes and a 50 K difference in the predicted average outlet gas temperatures. -- Highlights: ► Oxy-coal combustion simulations with dry and wet flue gas recycle was studied. ► Temperatures were more sensitive to devolatilization models than radiation models. ► Gray and non-gray modeling differences were amplified in larger geometries. ► Higher flame temperatures also contributed to model differences. ► Predictions from two recently proposed non-gray WSGG models were similar

  14. Nitric oxide dioxygenation reaction by oxy-coboglobin models: in-situ low-temperature FTIR characterization of coordinated peroxynitrite.

    Kurtikyan, Tigran S; Eksuzyan, Shahane R; Hayrapetyan, Vardan A; Martirosyan, Garik G; Hovhannisyan, Gohar S; Goodwin, John A

    2012-08-22

    The oxy-cobolglobin models of the general formula (NH(3))Co(Por)(O(2)) (Por = meso-tetra-phenyl and meso-tetra-p-tolylporphyrinato dianions) were constructed by sequential low temperature interaction of NH(3) and dioxygen with microporous layers of Co-porphyrins. At cryogenic temperatures small increments of NO were introduced into the cryostat and the following reactions were monitored by the FTIR and UV-visible spectroscopy during slow warming. Upon warming the layers from 80 to 120 K a set of new IR bands grows with correlating intensities along with the consumption of the ν(O(2)) band. Isotope labeling experiments with (18)O(2), (15)NO and N(18)O along with DFT calculations provides a basis for assigning them to the six-coordinate peroxynitrite complexes (NH(3))Co(Por)(OONO). Over the course of warming the layers from 140 to 170 K these complexes decompose and there are spectral features suggesting the formation of nitrogen dioxide NO(2). Upon keeping the layers at 180-210 K the bands of NO(2) gradually decrease in intensity and the set of new bands grows in the range of 1480, 1270, and 980 cm(-1). These bands have their isotopic counterparts when (15)NO, (18)O(2) and N(18)O are used in the experiments and certainly belong to the 6-coordinate nitrato complexes (NH(3))Co(Por)(η(1)-ONO(2)) demonstrating the ability of oxy coboglobin models to promote the nitric oxide dioxygenation (NOD) reaction similar to oxy-hemes. As in the case of Hb, Mb and model iron-porphyrins, the six-coordinate nitrato complexes are not stable at room temperature and dissociate to give nitrate anion and oxidized cationic complex Co(III)(Por)(NH(3))(1,2). PMID:22881578

  15. The Case for Tetrahedral Oxy-subhydride (TOSH) Structures in the Exclusion Zones of Anchored Polar Solvents Including Water

    Klaus Oehr; Paul H. LeMay

    2014-01-01

    We hypothesize a mechanistic model of how negatively-charged exclusion zones (EZs) are created. While the growth of EZs is known to be associated with the absorption of ambient photonic energy, the molecular dynamics giving rise to this process need greater elucidation. We believe they arise due to the formation of oxy-subhydride structures (OH−)(H2O)4 with a tetrahedral (sp3) (OH−)(H2O)3 core. Five experimental data sets derived by previous researchers were assessed in this regard: (1) water...

  16. Biomass co-firing under oxy-fuel conditions: A computational fluid dynamics modelling study and experimental validation

    Álvarez González, Lucía; Yin, C.; Riaza Benito, Juan; Pevida García, Covadonga; Pis Martínez, José Juan; Rubiera González, Fernando

    2014-01-01

    This paper presents an experimental and numerical study on co-firing olive waste (0, 10%, 20% on mass basis) with two coals in an entrained flow reactor under three oxy-fuel conditions (21%O2/79%CO2, 30%O2/70%CO2 and 35%O2/65%CO2) and air–fuel condition. Co-firing biomass with coal was found to have favourable synergy effects in all the cases: it significantly improves the burnout and remarkably lowers NOx emissions. The reduced peak temperatures during co-firing can also help to mitigate dep...

  17. Characterization of a limestone in a batch fluidized bed reactor for sulfur retention under oxy-fuel operating conditions

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

    2011-01-01

    CO2 and SO2 are some of the main polluting gases emitted into atmosphere in combustion processes using fossil fuel for energy production. The former is one of the major contributors to build-up the greenhouse effect implicated in global climate change and the latter produces acid rain. Oxy-fuel combustion is a technology, which consists in burning the fuel with a mix of pure O2 and recirculated CO2. With this technology the CO2 concentration in the flue gas may be enriched up to 95%, becoming...

  18. tert-Butyl N-[2-(N-isobutyl-4-meth-oxy-benzene-sulfonamido)-eth-yl]carbamate.

    Bai, Xiao-Guang; Wang, Ju-Xian

    2014-06-01

    The title compound, C18H30N2O5S, was synthesized by the reaction of tert-butyl 2-(iso-butyl-amino)-ethyl-carbamate with p-meth-oxy-phenyl-sulfonyl chloride. In the mol-ecule, two intra-molecular C-H⋯O hydrogen bonds are observed. In the crystal, mol-ecules are linked by N-H⋯O hydrogen bonds involving the imino group N atom and the ester group O atom into chains running parallel to the b axis. The chains are further connected by C-H⋯O hydrogen bonds, forming layers parallel to the bc plane. PMID:24940254

  19. (E)-4-Meth­oxy-2-(p-tolyl­imino­meth­yl)phenol

    Koşar, Başak; Özek, Arzu; Albayrak, Çiğdem; Büyükgüngör, Orhan

    2010-01-01

    The mol­ecule of the title compound, C15H15NO2, adopts the enol–imine tautomeric form and has a strong intra­molecular O—H⋯N hydrogen bond as a result. The mol­ecule is almost planar, with a maximum deviation of 0.1038 (15) Å for the meth­oxy C atom. A weak C—H⋯π inter­action and a weak C—H⋯O hydrogen bond are present in the crystal.

  20. Quantification of PAHs and oxy-PAHs on airborne particulate matter in Chiang Mai, Thailand, using gas chromatography high resolution mass spectrometry

    Walgraeve, Christophe; Chantara, Somporn; Sopajaree, Khajornsak; De Wispelaere, Patrick; Demeestere, Kristof; Van Langenhove, Herman

    2015-04-01

    An analytical method using gas chromatography high resolution mass spectrometry was developed for the determination of 16 polycyclic aromatic hydrocarbons (PAHs) and 12 oxygenated PAHs (of which 4 diketones, 3 ketones, 4 aldehydes and one anhydride) on atmospheric particulate matter with an aerodynamic diameter less than 10 μm (PM10). The magnetic sector mass spectrometer was run in multiple ion detection mode (MID) with a mass resolution above 10 000 (10% valley definition) and allows for a selective accurate mass detection of the characteristic ions of the target analytes. Instrumental detection limits between 0.04 pg and 1.34 pg were obtained for the PAHs, whereas for the oxy-PAHs they ranged between 0.08 pg and 2.13 pg. Pressurized liquid extraction using dichloromethane was evaluated and excellent recoveries ranging between 87% and 98% for the PAHs and between 74% and 110% for 10 oxy-PAHs were obtained, when the optimum extraction temperature of 150 °C was applied. The developed method was finally used to determine PAHs and oxy-PAHs concentration levels from particulate matter samples collected in the wet season at 4 different locations in Chiang Mai, Thailand (n = 72). This study brings forward the first concentration levels of oxy-PAHs in Thailand. The median of the sum of the PAHs and oxy-PAHs concentrations was 3.4 ng/m3 and 1.1 ng/m3 respectively, which shows the importance of the group of the oxy-PAHs as PM10 constituents. High molecular weight PAHs contributed the most to the ∑PAHs. For example, benzo[ghi]perylene was responsible for 30-44% of the ∑PAHs. The highest contribution to ∑oxy-PAHs came from 1,8-napthalic anhydride (26-78%), followed by anthracene-9,10-dione (4-27%) and 7H-benzo[de]anthracene-7-one (6-26%). Indications of the degradation of PAHs and/or formation of oxy-PAHs were observed.

  1. Lasing potentialities and white light generation capabilities of Dy3+ doped oxy-fluoroborate glasses

    Oxy-fluoroborate (OFB) glasses doped with different concentrations of Dy3+ ions were synthesized through melt quenching technique and characterized by using optical absorption, photoluminescence and decay analysis to understand the lasing potentialities and their utility for white light emitting diodes (LEDs). The XRD spectrum recorded for undoped OFB glass confirms the amorphous nature of the prepared glasses. Judd–Ofelt theory has been applied to the recorded absorption spectra to measure the radiative properties such as transition probability (AR), radiative lifetimes (τR), branching ratios (βR) and spectroscopic quality factor (χ) for the prominent fluorescent levels. The emission spectra recorded for these glasses gives four emission transitions 4F9/2→6H15/2, 6H13/2, 6H11/2 and 6H9/2 for which effective band widths (ΔλP), experimental branching ratios (βexp) and stimulated emission cross-sections (σse) are evaluated. To know the lasing potentialities of these glasses, the quantum efficiency (η) of these glasses are measured by recording the decay curves for the prominent emission levels 4F9/2→6H15/2 and 4F9/2→6H13/2. Among the observed emission transitions, a transition at 575 nm (4F9/2→6H13/2) indicates the lasing potentialities. The CIE chromaticity co-ordinates and the confocal photoluminescence images of these glasses further suggests the near white light generation capabilities in principle

  2. Oxidatively Electrodeposited Thin-Film Transition Metal (Oxy)hydroxides as Oxygen Evolution Catalysts.

    Morales-Guio, Carlos G; Liardet, Laurent; Hu, Xile

    2016-07-20

    The electrolysis of water to produce hydrogen and oxygen is a simple and attractive approach to store renewable energies in the form of chemical fuels. The oxygen evolution reaction (OER) is a complex four-electron process that constitutes the most energy-inefficient step in water electrolysis. Here we describe a novel electrochemical method for the deposition of a family of thin-film transition metal (oxy)hydroxides as OER catalysts. The thin films have nanodomains of crystallinity with lattice spacing similar to those of double-layered hydroxides. The loadings of these thin-film catalysts were accurately determined with a resolution of below 1 μg cm(-2) using an electrochemical quartz microcrystal balance. The loading-activity relations for various catalysts were established using voltammetry and impedance spectroscopy. The thin-film catalysts have up to four types of loading-activity dependence due to film nucleation and growth as well as the resistance of the films. A zone of intrinsic activity has been identified for all of the catalysts where the mass-averaged activity remains constant while the loading is increased. According to their intrinsic activities, the metal oxides can be classified into three categories: NiOx, MnOx, and FeOx belong to category I, which is the least active; CoOx and CoNiOx belong to category II, which has medium activity; and FeNiOx, CoFeOx, and CoFeNiOx belong to category III, which is the most active. The high turnover frequencies of CoFeOx and CoFeNiOx at low overpotentials and the simple deposition method allow the fabrication of high-performance anode electrodes coated with these catalysts. In 1 M KOH and with the most active electrode, overpotentials as low as 240 and 270 mV are required to reach 10 and 100 mA cm(-2), respectively. PMID:27344954

  3. Thermally induced cation redistribution in Fe-bearing oxy-dravite and potential geothermometric implications

    Bosi, Ferdinando; Skogby, Henrik; Hålenius, Ulf

    2016-05-01

    Iron-bearing oxy-dravite was thermally treated in air and hydrogen atmosphere at 800 °C to study potential changes in Fe, Mg and Al ordering over the octahedrally coordinated Y and Z sites and to explore possible applications to intersite geothermometry based on tourmaline. Overall, the experimental data (structural refinement, Mössbauer, infrared and optical absorption spectroscopy) show that heating Fe-bearing tourmalines results in disordering of Fe over Y and Z balanced by ordering of Mg at Y, whereas Al does not change appreciably. The Fe disorder depends on temperature, but less on redox conditions. The degree of Fe3+-Fe2+ reduction is limited despite strongly reducing conditions, indicating that the f O2 conditions do not exclusively control the Fe oxidation state at the present experimental conditions. Untreated and treated samples have similar short- and long-range crystal structures, which are explained by stable Al-extended clusters around the O1 and O3 sites. In contrast to the stable Al clusters that preclude any temperature-dependent Mg-Al order-disorder, there occurs Mg diffusion linked to temperature-dependent exchange with Fe. Ferric iron mainly resides around O2- at O1 rather than (OH)-, but its intersite disorder induced by thermal treatment indicates that Fe redistribution is the driving force for Mg-Fe exchange and that its diffusion rates are significant at these temperatures. With increasing temperature, Fe progressively disorders over Y and Z, whereas Mg orders at Y according to the order-disorder reaction: YFe + ZMg → ZFe + YMg. The presented findings are important for interpretation of the post-crystallization history of both tourmaline and tourmaline host rocks and imply that successful tourmaline geothermometers may be developed by thermal calibration of the Mg-Fe order-disorder reaction, whereas any thermometers based on Mg-Al disorder will be insensitive and involve large uncertainties.

  4. Modeling of liquid ceramic precursor droplets in a high velocity oxy-fuel flame jet

    Production of coatings by high velocity oxy-fuel (HVOF) flame jet processing of liquid precursor droplets can be an attractive alternative method to plasma processing. This article concerns modeling of the thermophysical processes in liquid ceramic precursor droplets injected into an HVOF flame jet. The model consists of several sub-models that include aerodynamic droplet break-up, heat and mass transfer within individual droplets exposed to the HVOF environment and precipitation of ceramic precursors. A parametric study is presented for the initial droplet size, concentration of the dissolved salts and the external temperature and velocity field of the HVOF jet to explore processing conditions and injection parameters that lead to different precipitate morphologies. It is found that the high velocity of the jet induces shear break-up into several μm diameter droplets. This leads to better entrainment and rapid heat-up in the HVOF jet. Upon processing, small droplets (<5 μm) are predicted to undergo volumetric precipitation and form solid particles prior to impact at the deposit location. Droplets larger than 5 μm are predicted to form hollow or precursor containing shells similar to those processed in a DC arc plasma. However, it is found that the lower temperature of the HVOF jet compared to plasma results in slower vaporization and solute mass diffusion time inside the droplet, leading to comparatively thicker shells. These shell-type morphologies may further experience internal pressurization, resulting in possibly shattering and secondary atomization of the trapped liquid. The consequences of these different particle states on the coating microstructure are also discussed in this article

  5. A kinetic study of NO formation during oxy-fuel combustion of pyridine

    Highlights: ► Pyrolysis and combustion studies of pyridine are conducted on a flow reactor. ► We employ model compound to simulate fuel-nitrogen conversion in O2/CO2 atmosphere. ► Pyrolysis products serve as the input parameters of combustion simulation. ► High concentration of CO2 promotes reaction of HNO + M ↔ H + NO + M to suppress NO formation. -- Abstract: In this work, pyridine-N was converted into NO and N2 by using a flow reactor and the dominant NO evolution pathways were identified by means of a kinetic modeling under O2/CO2 atmosphere in temperature range of 1073–1473 K for different stoichiometries. The experimental results indicated higher temperatures promoted the formation of NO, with conversions varied from 1.26–18.64% to 3.85–43% for fuel-rich and fuel-lean conditions respectively. As for N2 formation, conversion of pyridine to N2 had a slight increase from 1073 to 1173 K then declined rapidly in oxidizing atmosphere, whereas this conversion stabilized at about 36% before decreasing to 29% above 1173 K in the presence of insufficient O2. Increasing the equivalence ratio led to a monotonic increase of NO in both O2/Ar and O2/CO2 atmospheres, and the gap between these atmospheres developed with α. The simulation results showed that the high CO2 concentration reduced the availability of oxygen thus altered the evolution of NO through promoting reaction HNO + M ↔ H + NO + M and limiting reaction HNO + O2 ↔ HO2 + NO. This was even more important at higher temperatures. Besides, the major pathways for NO consumption were taken through reaction with NCO and NH as intermediates. In general, the model of Terasa09 described the experimental trends well, and this combustion kinetic was applicable to oxy-fuel conditions.

  6. Coal pyrolysis and char burnout under conventional and oxy-fuel conditions

    Al-Makhadmeh, L.; Maier, J.; Scheffknecht, G. [Stuttgart Univ. (Germany). Institut fuer Verfahrenstechnik und Dampfkesselwesen

    2009-07-01

    Coal utilization processes such as combustion or gasification generally involve several steps i.e., the devolatilization of organic materials, homogeneous reactions of volatile matter with the reactant gases, and heterogeneous reactions of the solid (char) with the reactant gases. Most of the reported work about coal pyrolysis and char burnout were performed at low temperatures under environmental conditions related to the air firing process with single particle tests. In this work, coal combustion under oxy-fuel conditions is investigated by studying coal pyrolysis and char combustion separately in practical scales, with the emphasis on improving the understanding of the effect of a CO{sub 2}-rich gas environment on coal pyrolysis and char burnout. Two coals, Klein Kopje a medium volatile bituminous coal and a low-rank coal, Lausitz coal were used. Coal pyrolysis in CO{sub 2} and N{sub 2} environments were performed for both coals at different temperatures in an entrained flow reactor. Overall mass release, pyrolysis gas concentrations, and char characterization were performed. For char characterization ultimate analysis, particle size, and BET surface area were measured. Chars for both coals were collected at 1150 C in both CO{sub 2} and N{sub 2} environments. Char combustion was performed in a once-through 20 kW test facility in O{sub 2}/CO{sub 2} and O{sub 2}/N{sub 2} atmospheres. Besides coal quality, oxygen partial pressure was chosen as a variable to study the effect of the gas environment on char burnout. In general, it is found that the CO{sub 2} environment and coal rank have a significant effect on coal pyrolysis and char burnout. (orig.)

  7. Crystal structure of poly[di-aqua-(μ-2-carb-oxy-acetato-κ(3) O,O':O'')(2-carb-oxy-acetato-κO)di-μ-chlorido-dicobalt(II)].

    Bouaoud, Yasmina; Setifi, Zouaoui; Buvailo, Andrii; Potaskalov, Vadim A; Merazig, Hocine; Dénés, Georges

    2016-01-01

    The asymmetric unit of the title polymer, [Co2(C3H3O4)2Cl2(H2O)2] n , comprises one Co(II) atom, one water mol-ecule, one singly deprotonated malonic acid mol-ecule (HMal(-); systematic name 2-carb-oxy-acetate) and one Cl(-) anion. The Co(II) atom is octa-hedrally coordinated by the O atom of a water mol-ecule, by one terminally bound carboxyl-ate O atom of an HMal(-) anion and by two O atoms of a chelating HMal(-) anion, as well as by two Cl(-) anions. The Cl(-) anions bridge two Co(II) atoms, forming a centrosymmetric Co2Cl2 core. Each malonate ligand is involved in the formation of six-membered chelate rings involving one Co(II) atom of the dinuclear unit and at the same time is coordinating to another Co(II) atom of a neighbouring dinuclear unit in a bridging mode. The combination of chelating and bridging coordination modes leads to the formation of a two-dimensional coordination polymer extending parallel to (001). Within a layer, O-Hwater⋯Cl and O-Hwater⋯O hydrogen bonds are present. Adjacent layers are linked through O-H⋯O=C hydrogen bonds involving the carb-oxy-lic acid OH and carbonyl groups. PMID:26870577

  8. To Learn from the Successor Plan of Occidental Petroleum Corporation (OXY)%西方石油公司(OXY)接班人计划借鉴与启示

    王磊

    2015-01-01

    Occidental Petroleum Corporation (OXY) has gained a foothold and secured a continuous development in the fierce competition with international oil giants. The commercial success is partly attributed to its management which excels in many ways, including the availability of a highly qualified labor force that has played an extremely important role, especially the implementation of a successor plan for operations management and key positions which has become the core of the company's talent strategy.%美国西方石油公司(OXY)在与国际石油巨头们的激烈竞争中站稳脚跟并不断发展,取得了商业上的成功,其管理上有很多过人之处,其中拥有一支高素质人才队伍起了极其重要的作用,尤其是实施管理层和关键岗位接班人计划发挥了关键的人才保障作用,成为其人才战略的核心.

  9. 氧化苦参碱对癫痫大鼠学习记忆功能的影响%Effect of Oxymatrine on Learning and Memory in Epileptic Rats

    张琳娜; 周凤兰; 何沿虹; 白洁

    2012-01-01

    Objective To observe the effect of oxymatrine on learning and memory and the expression of p -JNK in hippocampus in epileptic rats induced by penicillin. Methods SD rats were randomly divided into saline control group (NS) , epilepsy group (EP) , oxymatraine group (OXY) and phenobarbital sodium group. Penicillin was injected intraperitoneally in rats to establish epilepsy rats model. Behavioral changes were observe. The spatial learning and memory was tested by Morris Water Maze (MWM) . The number of positive cell of p - JNK in hippocampus were measured. Results Compared with EP group, the learning and memory in OXY group were significantly improved; the expression of p -JNK was decreased. Conclusion OXY pro-tected the spatial learning and memory in epilptic rats.%目的 观察氧化苦参碱(Oxymatrine,OXY)对青霉素(Penicillin,PEN)致痫大鼠学习记忆功能和海马区p-JNK表达的影响.方法 成年SD大鼠随机分为生理盐水对照组、青霉素致痫(EP)组(800万U·kg-1)、氧化苦参碱组(147.45mg·kg-1)和苯巴比妥钠(10mg·kg-1)阳性对照组,腹腔注射青霉素诱导大鼠癫痫发作,观察大鼠行为学改变,Morris水迷宫检测大鼠空间学习和记忆,免疫组化检测大鼠海马区p-JNK阳性细胞数.结果 与EP组相比,OXY 组大鼠空间记忆能力明显改善;海马组织内p-JNK阳性细胞数明显降低.结论 OXY可以对癫痫大鼠在空间学习和记忆方面起到保护作用.

  10. Combustion characteristics and air pollutant formation during oxy-fuel co-combustion of microalgae and lignite.

    Gao, Yuan; Tahmasebi, Arash; Dou, Jinxiao; Yu, Jianglong

    2016-05-01

    Oxy-fuel combustion of solid fuels is seen as one of the key technologies for carbon capture to reduce greenhouse gas emissions. The combustion characteristics of lignite coal, Chlorella vulgaris microalgae, and their blends under O2/N2 and O2/CO2 conditions were studied using a Thermogravimetric Analyzer-Mass Spectroscopy (TG-MS). During co-combustion of blends, three distinct peaks were observed and were attributed to C. vulgaris volatiles combustion, combustion of lignite, and combustion of microalgae char. Activation energy during combustion was calculated using iso-conventional method. Increasing the microalgae content in the blend resulted in an increase in activation energy for the blends combustion. The emissions of S- and N-species during blend fuel combustion were also investigated. The addition of microalgae to lignite during air combustion resulted in lower CO2, CO, and NO2 yields but enhanced NO, COS, and SO2 formation. During oxy-fuel co-combustion, the addition of microalgae to lignite enhanced the formation of gaseous species. PMID:26894568

  11. Energy transfer kinetics in oxy-fluoride glass and glass-ceramics doped with rare-earth ions

    An investigation of donor-acceptor energy transfer kinetics in dual rare earths doped precursor oxy-fluoride glass and its glass-ceramics containing NaYF4 nano-crystals is reported here, using three different donor-acceptor ion combinations such as Nd-Yb, Yb-Dy, and Nd-Dy. The precipitation of NaYF4 nano-crystals in host glass matrix under controlled post heat treatment of precursor oxy-fluoride glasses has been confirmed from XRD, FESEM, and transmission electron microscope (TEM) analysis. Further, the incorporation of dopant ions inside fluoride nano-crystals has been established through optical absorption and TEM-EDX analysis. The noticed decreasing trend in donor to acceptor energy transfer efficiency from precursor glass to glass-ceramics in all three combinations have been explained based on the structural rearrangements that occurred during the heat treatment process. The reduced coupling phonon energy for the dopant ions due to fluoride environment and its influence on the overall phonon assisted contribution in energy transfer process has been illustrated. Additionally, realization of a correlated distribution of dopant ions causing clustering inside nano-crystals has also been reported.

  12. High-temperature-oxidation-induced ordered structure in Inconel 939 superalloy exposed to oxy-combustion environments

    Zhu, Jingxi; Wise, Adam; Nuhfer, Thomas; Holcomb, Gordon R; Jablonski, Paul D; Sridhar, Seetharaman; Laughlin, David E

    2013-04-20

    In the integrated oxy-fuel combustion and turbine power generation system, turbine alloys are exposed to high temperature and an atmosphere comprised of steam, CO2 and O2. While surface and internal oxidation of the alloy takes place, the microstructure in the subsurface region also changes due to oxidation that results in the loss of the strengthening precipitates. In an earlier study of the oxidation of Inconel 939 Ni-based superalloy exposed to oxy-fuel combustion environment for up to 1000 hours, a high-temperature-oxidation-induced phase transformation in the sub-surface region was noticed and a two-phase region formed at the expense of strengthening γ' phase. While one of the two phases was identified as the Ni-matrix (γ solid solution, face-center-cubic) phase, the other product phase remained unidentified. In this study, the crystal structure of the unknown phase and its orientation relationship with the parent Ni-matrix phase was investigated through electron diffraction and high-resolution transmission electron microscopy. It was determined that the crystal structure of the unknown phase could be modeled as a ternary derivative of the ordered η-Ni3Ti phase (D024) structure with lattice parameters of a = 0.5092 nm and c = 0.8336 nm, α = 90º, β = 90º and γ = 120º.

  13. Assessing the Role of Particles in Radiative Heat Transfer during Oxy-Combustion of Coal and Biomass Blends

    Gautham Krishnamoorthy

    2015-01-01

    Full Text Available This study assesses the required fidelities in modeling particle radiative properties and particle size distributions (PSDs of combusting particles in Computational Fluid Dynamics (CFD investigations of radiative heat transfer during oxy-combustion of coal and biomass blends. Simulations of air and oxy-combustion of coal/biomass blends in a 0.5 MW combustion test facility were carried out and compared against recent measurements of incident radiative fluxes. The prediction variations to the combusting particle radiative properties, particle swelling during devolatilization, scattering phase function, biomass devolatilization models, and the resolution (diameter intervals employed in the fuel PSD were assessed. While the wall incident radiative flux predictions compared reasonably well with the experimental measurements, accounting for the variations in the fuel, char and ash radiative properties were deemed to be important as they strongly influenced the incident radiative fluxes and the temperature predictions in these strongly radiating flames. In addition, particle swelling and the diameter intervals also influenced the incident radiative fluxes primarily by impacting the particle extinction coefficients. This study highlights the necessity for careful selection of particle radiative property, and diameter interval parameters and the need for fuel fragmentation models to adequately predict the fly ash PSD in CFD simulations of coal/biomass combustion.

  14. Crystal structure of cis-2-(2-carb-oxy-cyclo-prop-yl)glycine (CCG-III) monohydrate.

    Lindeman, Sergey; Wallock, Nathaniel J; Donaldson, William A

    2015-07-01

    The title compound, C6H9NO4·H2O [systematic name: (αR,1R,2S)-rel-α-amino-2-carb-oxy-cyclo-propane-acetic acid monohydrate], crystallizes with two organic mol-ecules and two water mol-ecules in the asymmetric unit. The space group is P21 and the organic mol-ecules are enanti-omers, thus this is an example of a 'false conglomerate' with two mol-ecules of opposite handedness in the asymmetric unit (r.m.s. overlay fit = 0.056 Å for one mol-ecule and its inverted partner). Each mol-ecule exists as a zwitterion, with proton transfer from the amino acid carb-oxy-lic acid group to the amine group. In the crystal, the components are linked by N-H⋯O and O-H⋯O hydrogen bonds, generating (100) sheets. Conformationally restricted glutamate analogs are of inter-est due to their selective activation of different glutamate receptors, and the naturally occurring (+)-CCG-III is an inhibitor of glutamate uptake and the key geometrical parameters are discussed. PMID:26279882

  15. Crystal structure of 3-(2,5-di­meth­oxy­phen­yl)propionic acid

    Bugenhagen, Bernhard; Al Jasem, Yosef; AlAzani, Mariam; Thiemann, Thies

    2015-01-01

    In the crystal of the title compound, C11H14O4, the aromatic ring is almost coplanar with the 2-position meth­oxy group with which it subtends a dihedral of 0.54 (2)°, while the 5-position meth­oxy group makes a corresponding dihedral angle of just 5.30 (2)°. The angle between the mean planes of the aromatic ring and the propionic acid group is 78.56 (2)°. The fully extended propionic side chain is in a trans configuration with a C—C—C—C torsion angle of −172.25 (7)°. In the crystal, hydrogen bonding is limited to dimer formation via R 2 2(8) rings. The hydrogen-bonded dimers are stacked along the b axis. The average planes of the two benzene rings in a dimer are parallel to each other, but at an offset of 4.31 (2) Å. Within neighbouring dimers along the [101] direction, the average mol­ecular benzene planes are almost perpendicular to each other, with a dihedral angle of 85.33 (2)°. PMID:25995936

  16. DETERMINATION OF THE KINETIC PARAMETERS OF OXY-FUEL COMBUSTION OF COAL WITH A HIGH ASH CONTENT

    K. G. P. Nunes

    2015-03-01

    Full Text Available Abstract The aim of this study was to determine the kinetic parameters of the oxy-fuel combustion of char from a Brazilian bituminous coal with a high ash content. The char, with a particle diameter of 715 μm, was prepared in a N2 atmosphere at 1173 K. The oxy-fuel combustion assays were performed using a thermobalance at different temperatures and O2/CO2 gas mixtures of different concentrations. According to the unreacted core model, the process is determined by chemical reaction at low temperatures, with an activation energy of 56.7 kJ.kmol-1, a reaction order of 0.5 at 973 K and a reaction order of 0.7 overall. The use of the continuous reaction model did not provide a good fit for the experimental data because the consumption of the particles during the reaction was not constant, as predicted by the model. According to the Langmuir-Hinshelwood model, the activation energy for the first step was 37.3 kJ.kmol-1.

  17. Overview of ultraviolet and infrared spectroscopic properties of Yb3+ doped borate and oxy-borates compounds

    The trivalent ytterbium ion can give rise to two emissions with different spectroscopic properties: the first one, with a short lifetime, in the ultraviolet (charge transfer emission) is used in detectors such as scintillators, and the other one, with a long lifetime, in the infrared (4f-4f emission) for laser applications. The strong link between material structure and properties is illustrated through ytterbium luminescence study, in the ultraviolet and infrared, inserted in the borate Li6Y(BO3)3 and two oxy-borates: LiY6O5(BO3)3 and Y17,33B8O38. For the first time an ytterbium charge transfer emission in oxy-borates has been observed. The calculation of the single configurational coordinate diagram, as well as the thermal quenching, has been conducted under a fundamental approach on the ytterbium - oxygen bond. The study of the ytterbium infrared spectroscopy in these compounds has been realised and an energy level attribution is proposed in the particular case of the borate Li6Y(BO3)3: Yb3+. An original approach is introduced with the study of the charge transfer states for the three compounds by looking at the infrared emission. The first laser performances in three operating modes (continuous wave, Q-switch and mode locking) of a Li6Y(BO3)3: Yb3+ crystal are reported. (author)

  18. The Case for Tetrahedral Oxy-subhydride (TOSH Structures in the Exclusion Zones of Anchored Polar Solvents Including Water

    Klaus Oehr

    2014-11-01

    Full Text Available We hypothesize a mechanistic model of how negatively-charged exclusion zones (EZs are created. While the growth of EZs is known to be associated with the absorption of ambient photonic energy, the molecular dynamics giving rise to this process need greater elucidation. We believe they arise due to the formation of oxy-subhydride structures (OH−(H2O4 with a tetrahedral (sp3 (OH−(H2O3 core. Five experimental data sets derived by previous researchers were assessed in this regard: (1 water-derived EZ light absorbance at specific infrared wavelengths, (2 EZ negative potential in water and ethanol, (3 maximum EZ light absorbance at 270 nm ultraviolet wavelength, (4 ability of dimethyl sulphoxide but not ether to form an EZ, and (5 transitory nature of melting ice derived EZs. The proposed tetrahedral oxy-subhydride structures (TOSH appear to adequately account for all of the experimental evidence derived from water or other polar solvents.

  19. CO{sub 2} and H{sub 2}O diluted oxy-fuel combustion for zero-emission power

    Richards, G.A.; Casleton, K.H.; Chorpening, B.T. [US DOE, Morgantown, WV (United States). National Energy Technology Lab.

    2005-03-01

    Concerns about climate change have encouraged significant interest in concepts for zero-emission power generation systems. These systems are intended to produce power without releasing CO{sub 2} into the atmosphere. One approach is to replace the nitrogen diluent that accompanies conventional combustion in air with either CO{sub 2} or H{sub 2}O. In this concept, CO{sub 2} or H{sub 2}O is added to oxygen to control combustion temperatures in oxygen-fuel reactions. In the absence of nitrogen, the primary combustion products for any hydrocarbon under lean conditions are then simply CO{sub 2} and H{sub 2}O. Thus, merely cooling the exhaust stream condenses the water and produces an exhaust of pure CO{sub 2}, ready for sequestration. The dilute oxy-fuel combustion strategy can be incorporated in power cycles that are similar to Brayton or Rankine configurations, using CO{sub 2} or H{sub 2}O as the primary diluent respectively. In this paper, the expected combustion performance of CO{sub 2} and H{sub 2}O diluted systems are compared. Experimental results from a high-pressure oxy-fuel combustor are also presented.

  20. ENTHALPY RELAXATIONS AND CONCENTRATION FLUCTUATIONS IN BLENDS OF POLYSTYRENE AND POLY(OXY-2,6-DIMETHYL-1,4-PHENYLENE)

    OUDHUIS, AACM; TENBRINKE, G

    1992-01-01

    A series of enthalpy relaxation measurements were carried out for the pure polymers polystyrene (PS) and poly(oxy-2,6-dimethyl-1,4-phenylene) (PPE) and for homogeneous blends thereof. The data were analyzed using Moynihan's four-parameter approach.4 For the pure components the best fit parameter val

  1. Atomic arrangements around the O3 site in Al- and Cr-rich oxy-tourmalines: a combined EMP, SREF, FTIR and Raman study

    Bosi, Ferdinando; Skogby, Henrik; Lazor, Peter; Reznitskii, Leonid

    2015-06-01

    A study of natural oxy-tourmalines belonging to the system oxy-dravite-chromo-alumino-povondraite-oxy-chromium-dravite from the Sludyanka crystalline complex (Southern Baikal region, Russia) was carried out to explore the characteristic vibrational bands in the principal (OH)-stretching frequency and their relations to the O3 anion site of the tourmaline structure. Relevant information was obtained using electron microprobe analysis (EMPA), structural refinement (SREF), infrared (IR) and Raman single-crystal spectroscopy. The studied oxy-tourmalines are characterized by the substitution Al ↔ Cr, which is accompanied by redistribution of Mg over the Y and Z sites. The occurrence of strong correlations between relative peak area intensities for two IR bands at 3,565 and 3,519 cm-1 and cation site populations derived from SREF and EMP data allowed assignment of the band at 3,565 cm-1 to the cluster [ Y Mg Z Al Z (Al,Mg)]-O3 and the band at 3,519 cm-1 to the cluster [ Y Cr Z (Cr,Al) Z (Cr,Al,Mg))]-O3. It appears that the combination of polarized IR and Raman spectra collected with the electric vector E⊥ c and E// c may provide a useful characterization of the local (OH) environments around the O3 site of the tourmaline structure.

  2. Titanium dioxide reinforced hydroxyapatite coatings deposited by high velocity oxy-fuel (HVOF) spray.

    Li, H; Khor, K A; Cheang, P

    2002-01-01

    Hydroxyapatite (HA) coatings with titania addition were produced by the high velocity oxy-fuel (HVOF) spray process. Mechanical properties of the as-sprayed coatings in terms of adhesive strength, shear strength and fracture toughness were investigated to reveal the effect of the titania reinforcement on HA. Qualitative phase analysis with X-ray diffraction (XRD) showed that mutual chemical reaction between TiO2 and HA, that formed CaTiO3 occurred during coating formation. Differential scanning calorimetry (DSC) analysis of the starting powders showed that the mutual chemical reaction temperature was approximately 1410 degrees C and the existence of TiO2 can effectively inhibit the decomposition of HA at elevated temperatures. The positive influence of TiO2 addition on the shear strength was revealed. The incorporation of 10 vol% TiO2 significantly improved the Young's modulus of HA coatings from 24.82 (+/- 2.44) GPa to 43.23 (+/- 3.20) GPa. It decreased to 38.51 (+/- 3.65) GPa as the amount of TiO2 increased to 20 vol%. However, the addition of TiO2 has a negative bias on the adhesive strength of HA coatings especially when the content of TiO2 reached 20 vol%. This is attributed to the weak chemical bonding and brittle phases existing at the splats' interface that resulted from mutual chemical reactions. The fracture toughness exhibited values of 0.48 (+/- 0.08) MPa m0.5, 0.60 (+/- 0.07) MPa m0.5 and 0.67 (+/- 0.06) MPa m0.5 for the HA coating, 10 vol% TiO2 blended HA coating and 20 vol% TiO2 blended HA coating respectively. The addition of TiO2 in HA coating with the amount of less than 20 vol% is suggested for satisfactory toughening effect in HVOF HA coating. PMID:11762858

  3. Process analysis of pressurized oxy-coal power cycle for carbon capture application integrated with liquid air power generation and binary cycle engines

    Highlights: • We model a 573 MW pressurized oxy-coal combustion with supercritical steam cycle. • A 126 MW liquid air power plant was integrated to utilize the nitrogen stream. • We used organic Rankine cycle to recover heat from compressors. • The model was analysed for with and without carbon capture consideration. • Efficiency increase of 12–15% was achieved due to integration and heat recovery. - Abstract: In this paper, the thermodynamic advantage of integrating liquid air power generation (LAPG) process and binary cycle waste heat recovery technology to a standalone pressurized oxy-coal combustion supercritical steam power generation cycle is investigated through modeling and simulation using Aspen Plus® simulation software version 8.4. The study shows that the integration of LAPG process and the use of binary cycle heat engine which convert waste heat from compressor exhaust to electricity, in a standalone pressurized oxy-coal combustion supercritical steam power generation cycle improves the thermodynamic efficiency of the pressurized oxy-coal process. The analysis indicates that such integration can give about 12–15% increase in thermodynamic efficiency when compared with a standalone pressurized oxy-coal process with or without CO2 capture. It was also found that in a pressurized oxy-coal process, it is better to pump the liquid oxygen from the cryogenic ASU to a very high pressure prior to vapourization in the cryogenic ASU main heat exchanger and subsequently expand the gaseous oxygen to the required combustor pressure than either compressing the atmospheric gaseous oxygen produced from the cryogenic ASU directly to the combustor pressure or pumping the liquid oxygen to the combustor pressure prior to vapourization in the cryogenic ASU main heat exchanger. The power generated from the compressor heat in the flue gas purification, carbon capture and compression unit using binary cycle heat engine was also found to offset about 65% of the

  4. OxyR-dependent formation of DNA methylation patterns in OpvABOFF and OpvABON cell lineages of Salmonella enterica.

    Cota, Ignacio; Bunk, Boyke; Spröer, Cathrin; Overmann, Jörg; König, Christoph; Casadesús, Josep

    2016-05-01

    Phase variation of the Salmonella enterica opvAB operon generates a bacterial lineage with standard lipopolysaccharide structure (OpvAB(OFF)) and a lineage with shorter O-antigen chains (OpvAB(ON)). Regulation of OpvAB lineage formation is transcriptional, and is controlled by the LysR-type factor OxyR and by DNA adenine methylation. The opvAB regulatory region contains four sites for OxyR binding (OBSA-D), and four methylatable GATC motifs (GATC1-4). OpvAB(OFF) and OpvAB(ON) cell lineages display opposite DNA methylation patterns in the opvAB regulatory region: (i) in the OpvAB(OFF) state, GATC1 and GATC3 are non-methylated, whereas GATC2 and GATC4 are methylated; (ii) in the OpvAB(ON) state, GATC2 and GATC4 are non-methylated, whereas GATC1 and GATC3 are methylated. We provide evidence that such DNA methylation patterns are generated by OxyR binding. The higher stability of the OpvAB(OFF) lineage may be caused by binding of OxyR to sites that are identical to the consensus (OBSA and OBSc), while the sites bound by OxyR in OpvAB(ON) cells (OBSB and OBSD) are not. In support of this view, amelioration of either OBSB or OBSD locks the system in the ON state. We also show that the GATC-binding protein SeqA and the nucleoid protein HU are ancillary factors in opvAB control. PMID:26687718

  5. Crystal structures of the potassium and rubidium salts of (3,5-di-chloro-phen-oxy)acetic acid: two isotypic coordination polymers.

    Smith, Graham

    2015-10-01

    The two-dimensional coordination polymeric structures of the hydrated potassium and rubidium salts of (3,5-di-chloro-phen-oxy)acetic acid (3,5-D), namely, poly[μ-aqua-bis-[μ3-2-(3,5-di-chloro-phen-oxy)acetato]-dipotassium], [K2(C8H5Cl2O3)2(H2O)] n , and poly[μ-aqua-bis-[μ3-2-(3,5-di-chloro-phen-oxy)acetato]-dirubidium], [Rb2(C8H5Cl2O3)2(H2O)] n , respectively, have been determined and are described. The two compounds are isotypic and the polymeric structure is based on centrosymmetric dinuclear bridged complex units. The irregular six-coordination about the alkali cations comprises a bridging water mol-ecule lying on a twofold rotation axis, the phen-oxy O-atom donor and a triple bridging carboxyl-ate O atom of the oxo-acetate side chain of the 3,5-D ligand, and the second carb-oxy-ate O-atom donor also bridging. The K-O and Rb-O bond-length ranges are 2.7238 (15)-2.9459 (14) and 2.832 (2)-3.050 (2) Å, respectively, and the K⋯K and Rb⋯Rb separations in the dinuclear units are 4.0214 (7) and 4.1289 (6) Å, respectively. Within the layers which lie parallel to (100), the coordinating water mol-ecule forms an O-H⋯O hydrogen bond to the single bridging carboxyl-ate O atom. PMID:26594400

  6. Interaction of cationic dodecyl-trimethyl-ammonium bromide with oxy-HbGp by isothermal titration and differential scanning calorimetric studies: Effect of proximity of isoelectric point.

    Alves, Fernanda Rosa; Carvalho, Francisco Adriano O; Carvalho, José Wilson P; Tabak, Marcel

    2016-04-01

    In this work, isothermal titration and differential scanning calorimetric methods, in combination with pyrene fluorescence emission and dynamic light scattering have been used to investigate the interaction of dodecyltrimethylammonium bromide (DTAB) with the giant extracellular Glossoscolex paulistus hemoglobin (HbGp) in the oxy-form, at pH values around the isoelectric point (pI ≈ 5.5). Our ITC results have shown that the interaction of DTAB with the hemoglobin is more intense at pH 7.0, with a smaller cac (critical aggregation concentration) value. The increase of protein concentration does not influence the cac value of the interaction, at both pH values. Therefore, the beginning of the DTAB-oxy-HbGp premicellar aggregates formation, in the cac region, is not affected by the increase of protein concentration. HSDSC studies show higher Tm values at pH 5.0, in the absence and presence of DTAB, when compared with pH 7.0. Furthermore, at pH 7.0, an aggregation process is observed with DTAB in the range from 0.75 to 1.5 mmol/L, noticed by the exothermic peak, and similar to that observed for pure oxy-HbGp, at pH 5.0, and in the presence of DTAB. DLS melting curves show a decrease on the hemoglobin thermal stability for the oxy-HbGp-DTAB mixtures and formation of larger aggregates, at pH 7.0. Our present data, together with previous results, support the observation that the protein structural changes, at pH 7.0, occur at smaller DTAB concentrations, as compared with pH 5.0, due to the acidic pI of protein that favors the oxy-HbGp-cationic surfactant interaction at neutral pH. PMID:26574155

  7. Increase in oxytocin and vasopressin concentration in the blood outflowing from sella turcica region after superior cervical ganglion stimulation in rat

    The aim of the study was to investigate whether the stimulation of the superior cervical ganglion influences the oxytocin and vasopressin release into the blood in condition of the of the sella turcica integrity. The experiments were performed on male rats under urethane-chloralose anaesthesia. Four 0.7 ml samples of the blood from the sella turcica region flowing through a tube inserted in the maxillary interna vein were collected in the 30, 35, 60 and 90 min of the experiments. The animals were divided into three groups: 1) control, 2) after the exposition of superior cervical ganglion. 3) after the collection of the 1-st sample of the blood the superior cervical ganglion was electrically stimulated for 30 min with trains of pulses. Vasopressin (AVP) and oxytocin (OXY) were determined in the blood plasma by radioimmunoassay. Stimulation of the superior cervical ganglion evoked an significant increase of AVP and OXY release into the blood. The increase of AVP release occurred after 30 min longer latency than the increase of OXY release. (author). 32 refs, 2 figs

  8. Increase in oxytocin and vasopressin concentration in the blood outflowing from sella turcica region after superior cervical ganglion stimulation in rat

    Lipinska, S.; Orlowska-Majdak, M.; Traczyk, W.Z. [Akademia Medyczna, Lodz (Poland). Katedra Fizjologii

    1996-12-31

    The aim of the study was to investigate whether the stimulation of the superior cervical ganglion influences the oxytocin and vasopressin release into the blood in condition of the of the sella turcica integrity. The experiments were performed on male rats under urethane-chloralose anaesthesia. Four 0.7 ml samples of the blood from the sella turcica region flowing through a tube inserted in the maxillary interna vein were collected in the 30, 35, 60 and 90 min of the experiments. The animals were divided into three groups: 1) control, 2) after the exposition of superior cervical ganglion. 3) after the collection of the 1-st sample of the blood the superior cervical ganglion was electrically stimulated for 30 min with trains of pulses. Vasopressin (AVP) and oxytocin (OXY) were determined in the blood plasma by radioimmunoassay. Stimulation of the superior cervical ganglion evoked an significant increase of AVP and OXY release into the blood. The increase of AVP release occurred after 30 min longer latency than the increase of OXY release. (author). 32 refs, 2 figs.

  9. Burned after reading: the so-called list of Alexandrian librarians in P. Oxy. X 1241 Brûlée après lecture : la liste dite des Bibliothécaires d'Alexandrie dans le P.Oxy. X 1241 Burned after reading; la cosiddetta lista di bibliotecari alessandrini in P.Oxy. X 1241

    Jackie Murray

    2012-06-01

    Full Text Available Cet article remet en question la valeur et la fiabilité du contenu du P.Oxy. X 1241, la liste dite des Bibliothécaires d’Alexandrie. Plutôt que de traiter de la liste des grammairiens des colonnes i.5.-ii.30 pour elle-même, comme les savants l’ont fait depuis que le papyrus a été publié, cet article prend en considération le document dans son intégralité. Cette lecture plus attentive du P.Oxy. X 1241 démontre qu’il y a une évidente continuité thématique entre la liste des grammairiens et les catalogues militaires qui suivent, qui n’a jamais été observée précédemment parce que les deux parties du document ont été traitées séparement. Il en découle des questions concernant trois hypothèses essentielles émises par les éditeurs originaux, B. P. Grenfell et A. S. Hunt : (1 la liste des col. i.5-ii.30 est-elle en réalité une liste des Bibliothécaires en chef de la Bibliothèque d’Alexandrie ? (2 le document est-il une copie ou une compilation de quelque œuvre savante qui remonte à la période hellénistique, et non la production d’un savant/grammairien du deuxième siècle de notre ère environ ? (3 Est-ce que les contenus du papyrus reflètent l’œuvre d’un savant/grammairien compétent qui était suffisamment informé sur la chronologie de la période ptolémaïque pour donner un décompte historiquement exact de la succession d’individus liés à la cour des Ptolémées et à la Bibliothèque d’Alexandrie ? S’il est vrai que dans son contenu et son utilisation de citations savantes le P.Oxy. X 1241 partage de nombreux points communs avec les catalogues en prose des époques hellénistique et impériale, les stratégies du discours savant déployées par l’auteur dans le catalogue militaire ne sont pas conformes aux normes des exemples scientifiques fiables. En conséquence, la valeur du texte comme preuve documentaire de l’histoire de la Bibliothèque d’Alexandrie a besoin d

  10. Effects of Chronic Renal Failure on Brain Cytochrome P450 in Rats.

    Naud, Judith; Harding, Jessica; Lamarche, Caroline; Beauchemin, Stephanie; Leblond, Francois A; Pichette, Vincent

    2016-08-01

    Chronic renal failure (CRF) impedes renal excretion of drugs and their metabolism by reducing the expression of liver cytochrome P450 (P450). Uremic serum contains factors, such as parathyroid hormone (PTH), that decrease liver P450s. The P450s are also involved in the metabolism of xenobiotics in the brain. This study investigates: 1) the effects of CRF on rat brain P450, 2) the role of PTH in the downregulation of brain P450s in CRF rats, and 3) the effects of PTH on P450s in astrocytes. Protein and mRNA expression of P450s were assessed in the brain of CRF and control (CTL) rats, as well as from CTL or CRF rats that underwent parathyroidectomy (PTX) 1 week before nephrectomy. CYP3A activity was measured using 3-[(3, 4-difluorobenzyl) oxy]-5, 5-dimethyl-4-[4-methylsulfonyl) phenyl] furan-2(5H)-1 metabolism in brain microsomal preparation. CYP3A protein expression was assessed in primary cultured astrocytes incubated with serum obtained from CRF or CTL rats or with PTH. Significant downregulations (≥40%) of CYP1A, CYP2C11, and CYP3A proteins were observed in microsomes from CRF rat brains. CYP3A activity reduction was also observed. CYP3A expression and activity were unaffected in PTX-pretreated CRF rats. Serum of PTX-treated CRF rats had no impact on CYP3A levels in astrocytes compared with that of untreated CRF rats. Finally, PTH addition to normal calf serum induced a reduction in CYP3A protein similar to CRF serum, suggesting that CRF-induced hyperparathyroidism is associated with a significant decrease in P450 drug-metabolizing enzymes in the brain, which may have implications in drug response. PMID:27271372

  11. Electrochemically Stable Titanium Oxy-Nitride Support for Platinum Electro-Catalyst for PEM Fuel Cell Applications

    Titanium Oxy-Nitride is prepared by an in-situ urea-based sol-gel method as a support for the platinum electro-catalyst for the oxygen reduction reaction (ORR). XRD, BET, SEM and EDX are used to analyze the physicochemical properties of the prepared Pt/TiON catalyst; and its electrochemical properties are evaluated by CV and RDE tests. Electrochemical active surface area is determined and compared to that of the commercial Pt/C electro-catalyst. Pt/TiON electro-catalyst showed a better electrochemical stability than those of the commercial Pt/C electro-catalyst. It is also found that the ORR proceeds via four electron transfer mechanism on both Pt/C and Pt/TiON electro-catalysts

  12. (2E)-2-(4-Hy­droxy-3-meth­oxy­benzyl­idene)hydrazinecarboxamide

    Tahir, M. Nawaz; Ali, Akbar; Umar, M. Naveed; Hussain, Ishtiaq; Shad, Hazoor Ahmad

    2012-01-01

    In the title compound, C9H11N3O3, two mol­ecules are present in the asymmetric unit in which the 4-hy­droxy-3-meth­oxy­benzaldehyde and hydrazinecarboxamide units are almost planar [with r.m.s. deviations 0.0212 and 0.0066 Å, respectively, in one mol­ecule and 0.0346 and 0.0095 Å, respectively, in the other] and are oriented at dihedral angles of 9.7 (3) and 16.6 (3)°. In both mol­ecules, two S(5) ring motifs are present due to N—H⋯N and O—H⋯O hydrogen bonds. In the crystal, the mol­ecules ar...

  13. The effect of design and operating condition changes on the heat transfer in an oxy-fuel fired glass tank

    Jurcik, B.; Schnepper, C. [Air Liquide-Chicago Research Center, Countryside, IL (United States); Bechara, W.; Plessier, R.; Jouvaud, D. [L`Air Liquide, 78 - Les Loges-en-Josas (France). Centre de Recherche Claude-Delorme; Silva, E. da [Canadian Liquid Air Ltd., PQ (Canada)

    1995-05-01

    The conversion of conventional air-fired glass melting tanks to oxy-fuel fired tanks has been motivated by capital and operating cost savings, pollution control and improved manufacturing flexibility. A conversion study was performed on a glass melting tank that was typical of the industry, using numerical modelling techniques. The heat transfer effects were studied by comparing the two types of melting tanks. Mass and energy balances were presented for both conventional and modified cases. The importance of radiation losses through regenerator ports was demonstrated. It was found that thermal profiles on the glass surface were more uniform across the width of the furnace after conversion due to the staggered burner arrangement. A parametric study showed that global variables (energy transferred to the glass) and local variables (maximum refractory temperature) were affected by design changes. 6 figs., 2 tables

  14. A comparative study of the circulating and fixed bed reactors running. Application to the isobutyric acid oxy-dehydrogenation

    Bechara, R.; Lakraa, M.; Vanhove, D.; Pietrzyk, S. [Ecole Nationale Superieure de Chimie de Lille, 59 - Villeneuve d`Ascq (France); Hecquet, G. [Societe Nationale Elf-Aquitaine (France)

    1995-12-31

    This work deals with the study of the catalytic oxy-dehydrogenation process of the isobutyric acid in methacrylic acid on a Fe-Cs-P-O catalyst. The reaction has been carried out on two facilities: a circulating bed pilot reactor and a bench-scale packed bed reactor. Although there are considerable differences between the two reactors, a comparison has been established. When the reaction is carried out in the circulating bed reactor, an important ratio of carbonaceous species remain adsorbed at the catalyst surface. A more extensive analysis of the catalyst surface suggest that the main part of this adsorbed phase is probably methacrylic acid. (O.M.). 8 refs., 1 fig., 1 tab.

  15. Crystal structure of 4-hy-droxy-pyridin-1-ium 3,5-di-carb-oxy-benzoate.

    Staun, Selena L; Oliver, Allen G

    2015-07-01

    The structure of the title salt, C5H6NO(+)·C9H5O6 (-), (I), shows that 4-hy-droxy-pyridine has abstracted an H atom from benzene-1,3,5-tri-carb-oxy-lic acid, yielding a pyridinium cation and carboxyl-ate anion. The two ions form an extensive three-dimensional hydrogen-bonded network throughout the crystal. The hydrogen bonds that comprise the core of the network are considered strong, with O-H⋯O and N-H⋯O donor-to-acceptor distances ranging from 2.533 (2) to 2.700 (2) Å. Packing is further enhanced by π-stacking of the cations and anions with like species [centroid-centroid distance = 3.6206 (13) Å]. PMID:26279886

  16. Corrosion resistance of tungsten carbide based cermet coatings deposited by High Velocity Oxy-Fuel spray process

    WC-17Ni and WC-17Co coatings were deposited on mild steel and stainless steel substrates by High Velocity Oxy-Fuel (HVOF) spray process. WC-17Ni and WC-17Co coatings were obtained by the spray process and the porosity of these coatings was measured. Polarization and electrochemical impedance spectroscopy (EIS) were performed on both uncoated substrates and coated samples immersed in 3% NaCl solution. WC-17Ni coating with a lower porosity, serve as a better barrier and effectively prevented corrosion attack when it was deposited on mild steel substrate. The nickel binder in the WC-17Ni coating was found to have a better corrosion resistance than the cobalt binder in the WC-17Co coating

  17. Crystal structure of ammonium (3,5-di­chloro­phen­oxy)acetate hemihydrate

    Smith, Graham

    2015-01-01

    In the structure of the title hydrated salt, NH4 +·C8H5Cl2O3 −·0.5H2O, where the anion derives from (3,5-di­chloro­phen­oxy)acetic acid, the ammonium cation is involved in extensive N—H⋯O hydrogen bonding with both carboxyl­ate and ether O-atom acceptors giving sheet structures lying parallel to (100). The water mol­ecule of solvation lies on a crystallographic twofold rotation axis and is involved in intra-sheet O—H⋯Ocarboxyl­ate hydrogen-bonding inter­actions. In the anion, the oxoacetate s...

  18. A novel oxy-oxonia(azonia)-cope reaction: serendipitous discovery and its application to the synthesis of macrocyclic musks.

    Zou, Yue; Zhou, Lijun; Ding, Changming; Wang, Quanrui; Kraft, Philip; Goeke, Andreas

    2014-10-01

    This brief review, including new experimental results, is the summary of a talk at the GDCh conference 'flavors & fragrances 2013' in Leipzig, Germany, 11th-13th September, 2013. Musk odorants are indispensable in perfumery to lend sensuality to fine fragrances, a nourishing effect to cosmetics, and a comforting feeling to laundry. We have recently found serendipitously a new oxy-oxonia-Cope rearrangement. In this account, we review the background of oxonia-sigmatropic rearrangements and the discovery of this novel reaction. Special attention is focused on the versatile lactone and lactam formation reactions via [n+4] ring enlargement and the macrocyclization in the synthesis of new macrocyclic musks. The synthesized structures provide new insights into the structure-odor relationships of musks. PMID:25329787

  19. Methane coupling reaction in an oxy-steam stream through an OH radical pathway by using supported alkali metal catalysts

    Liang, Yin

    2014-03-24

    A universal reaction mechanism involved in the oxidative coupling of methane (OCM) is demonstrated under oxy-steam conditions using alkali-metal-based catalysts. Rigorous kinetic measurements indicated a reaction mechanism that is consistent with OH radical formation from a H 2O-O2 reaction followed by C-H activation in CH 4 with an OH radical. Thus, the presence of water enhances both the CH4 conversion rate and the C2 selectivity. This OH radical pathway that is selective for the OCM was observed for the catalyst without Mn, which suggests clearly that Mn is not the essential component in a selective OCM catalyst. The experiments with different catalyst compositions revealed that the OH.-mediated pathway proceeded in the presence of catalysts with different alkali metals (Na, K) and different oxo anions (W, Mo). This difference in catalytic activity for OH radical generation accounts for the different OCM selectivities. As a result, a high C2 yield is achievable by using Na2WO4/SiO2, which catalyzes the OH.-mediated pathway selectively. Make it methane: A universal reaction mechanism involved in the oxidative coupling of methane is demonstrated under oxy-stream conditions by using alkali-metal-based catalysts. Rigorous kinetic measurements indicated a reaction mechanism that is consistent with OH radical formation from an H2O-O2 reaction, followed by C-H activation in CH4 with an OH radical. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. An assessment of radiation modeling strategies in simulations of laminar to transitional, oxy-methane, diffusion flames

    Twenty four, laboratory scale, laminar to transitional, diffusion oxy-methane flames were simulated employing different radiation modeling options and their predictions compared against experimental measurements of: temperature, flame length and radiant fraction. The models employed were: gray and non-gray formulations of a recently proposed weighted-sum-of-gray gas model, non-adiabatic extension of the equilibrium based mixture fraction model and investigations into the effects of: the thermal boundary conditions, soot and turbulence radiation interactions (TRI). Predictions of gas, wall temperatures and flame lengths were in good agreement with experimental measurements. Flame lengths determined through the axial profiles of OH confirmed with the experimental trends by increasing with increase in fuel-inlet Reynolds numbers and decreasing with the increase in O2 composition in oxidizer. The temperature and flame length predictions were not sensitive to the radiative property model employed. There were significant variations between the gray and non-gray model radiant fraction predictions with the variations in general increasing with decrease in Reynolds numbers possibly attributed to shorter flames and steeper temperature gradients. The inclusion of soot model and TRI model did not affect our predictions as a result of low soot volume fractions and the radiation emission enhancement to the temperature fluctuations being localized to the flame sheet. -- Highlights: • Twenty four, lab scale, laminar to transitional, diffusion, oxy-methane flames were simulated. • Equilibrium model adequately predicted the temperature and flame lengths. • The experimental trends in radiant fractions were replicated. • Gray and non-gray model differences in radiant fractions were amplified at low Re. • Inclusion of soot and TRI models did not affect our predictions

  1. Heavy ion ERD of oxy-nitride and nitride films with a position-sensitive gas ionization detector

    Full text: The atomic composition of materials and thin films can be quantitatively profiled as function of sample depth with heavy ion elastic recoil detection (ERD). When using a high-energy, heavy incident beam, such as 200MeV gold ions, the sensitivity is similar for all elements and better than 0.1 atomic percent. A prime application of heavy ion ERD is the analysis of silicon oxy-nitride and gallium nitride films, which are developed for a variety of opto-electronic applications. The technique can simultaneously resolve all chemical elements in these films including hydrogen, which is often present as a contaminant. This presentation reports on detailed studies of oxy-nitride and nitride films using heavy ion ERD carried out at the 14UD pelletron accelerator at the Australian National University. For films thinner than about 1 μm, the substrate interface can be resolved and, assuming uniformity, the film composition can be directly obtained by normalizing the measured yield for each element with the corresponding recoil cross-sections. Deviations from uniformity are evident from the corresponding energy spectra. By calibrating these spectra using known stopping powers, depth-information may be obtained and possible variations of the composition can be quantified. The concentration change at the interface between substrate and film can be studied individually for each element. A major obstacle in the ERD analysis of nitride films, is their radiation sensitivity, which generally results in the depletion of the nitrogen and hydrogen content during exposure to the incident beam. Using a position-sensitive gas ionization detectors with large acceptance angle, such beam-induced sample modification can be minimized. Residual desorption was found to be linear with incident fluence and can thus be reliably corrected

  2. Assessment of oxy-fuel, pre- and post-combustion-based carbon capture for future IGCC plants

    Highlights: ► Hot gas cleanup is a highly favorable technology for all selected IGCC concepts. ► Proposed high pressure IGCC with membrane reactor enables direct CO2 condensation. ► IGCC with OTM and carbonate looping enable significant synergy effects. ► Combining IGCC and oxy-fuel is technically challenging but energetically favorable. ► All selected IGCC concepts are able to realize CO2 capture rates up to 99%. -- Abstract: Environmental damage due to the emission of greenhouse gases from conventional coal-based power plants is a growing concern. Various carbon capture strategies to minimize CO2 emissions are currently being investigated. Unfortunately, the efficiency drop due to de-carbonization is still significant and the capture rate is limited. Therefore three future hard coal IGCC concepts are assessed here, applying emerging technologies and various carbon capture approaches. The advanced pre-combustion capture concept is based on hot gas clean-up, membrane-enhanced CO conversion and direct CO2 condensation. The concept reached a net efficiency of 45.1% (LHV), representing an improvement of 6.46% compared to the conventional IGCC base case. The second IGCC concept, based on post-combustion capture via calcination–carbonation loops, hot gas clean-up and oxygen membranes, showed a net efficiency of 45.87% (LHV). The third IGCC concept applies hot gas clean-up and combustion of the unconverted fuel gas using pure oxygen. The oxygen is supplied by an integrated oxygen membrane. The combination of IGCC and oxy-fuel process reached a net efficiency of 45.74% (LHV). In addition to their increased efficiency, all of the concepts showed significantly improved carbon capture rates up to 99%, resulting in virtually carbon-free fossil power plants.

  3. FutureGen 2.0 Oxy-Coal Combustion Carbon Capture Plant Pre-FEED Design and Cost

    Flanigan, Tom; Pybus, Craig; Roy, Sonya; Lockwood, Frederick; McDonald, Denny; Maclnnis, Jim

    2011-09-30

    This report summarizes the results of the Pre-Front End Engineering Design (pre-FEED) phase of a proposed advanced oxy-combustion power generation plant to repower the existing 200 MWe Unit 4 at Ameren Energy Resources’ (AER) Meredosia Power Plant. AER has formed an alliance with Air Liquide Process and Construction, Inc. (ALPC) and Babcock & Wilcox Power Generation Group (B&W PGG) for the design, construction, and testing of the facility, and has contracted with URS Corporation (URS) for preliminary design and Owner’s engineering services. The Project employs oxy-combustion technology – combustion of coal with nearly pure oxygen and recycled flue gas (instead of air) – to capture approximately 90% of the flue gas CO2 for transport and sequestration by another Project. Plant capacity and configuration has been developed based on the B&W PGG-ALPC cool recycle process firing high-sulfur bituminous coal fuel, assuming baseload plant operation to maximize existing steam turbine capability, with limited consideration for plant redundancy and performance optimization in order to keep plant costs as low as practical. Activities and preliminary results from the pre-FEED phase addressed in this report include the following: Overall plant thermal performance; Equipment sizing and system configuration; Plant operation and control philosophy; Plant emissions and effluents; CO2 production and recovery characteristics; Project cost estimate and economic evaluation; Integrated project engineering and construction schedule; Project risk and opportunity assessment; Development of Project permitting strategy and requirements During the Phase 2 of the Project, additional design details will be developed and the Phase 1 work products updated to support actual construction and operation of the facility in Phase 3. Additional information will be provided early in Phase 2 to support Ameren-Environmental in finalizing the appropriate permitting strategies and permit

  4. Modeling oxy-fuel combustion in a 3D circulating fluidized bed using the hybrid Euler–Lagrange approach

    Results of experiments and numerical simulations of the coal oxy-fuel combustion process in an experimental circulating fluidized bed (CFB) are presented in this paper. The simulations were carried out using the hybrid Euler–Lagrange approach to model the dense particle transport in the CFB pilot installation combined with a model of the combustion process. The main aim of presented work is to demonstrate the applicability of the hybrid Euler–Lagrange technique for modeling the particle transport process in the CFB, which also includes the coal combustion process modeling. To the best knowledge of the authors, there is no implementation of the hybrid Euler–Lagrange Dense Discrete Phase Model (DDPM) approach for modeling the CFB in the 3D domain with combustion process simulations, which is available in literature. Both the experiments and numerical simulations were carried out for three oxidizer compositions O2/CO2, i.e. 21, 30, and 35% of the oxygen volume fraction. In order to investigate the numerical model sensitivity when combustion conditions change, additional tests were evaluated for case with 35% of the oxygen for three excess oxygen ratios equal to 1.05, 1.15, and 1.25. The important aspect of modeling the radiative heat transfer during the fluidization process combined with oxy-fuel combustion was also investigated. The set of numerical simulations was performed for different radiation model configurations. The numerical results were compared with the temperature profile measured within the combustion chamber of the pilot test rig. - Highlights: • Hybrid Euler–Lagrange approach has been used for modelling particle transport. • Numerical results have been validated against experimental data. • New strategy for resolving particle transport in circulating fluidized bed has been shown

  5. Studies on the metabolism of l-menthol in rats.

    Madyastha, K M; Srivatsan, V

    1988-01-01

    Metabolism of l-menthol in rats was investigated both in vivo and in vitro. Metabolites isolated and characterized from the urine of rats after oral administration (800 mg/kg of body weight/day) of l-menthol were the following: p-menthane-3,8-diol (II), p-menthane-3,9-diol (III), 3,8-oxy-p-menthane-7-carboxylic acid (IV), and 3,8-dihyroxy-p-menthane-7-carboxylic acid (V). In vivo, the major urinary metabolites were compounds II and V. Repeated oral administration (800 mg/kg of body weight/day) of l-menthol to rats for 3 days resulted in the increase of both liver microsomal cytochrome P-450 content and NADPH-cytochrome c reductase activity by nearly 80%. Further treatment (for 7 days total) reduced their levels considerably, although the levels were still higher than the control values. Both cytochrome b5 and NADH-cytochrome c reductase levels were not changed during the 7 days of treatment. Rat liver microsomes readily converted l-menthol to p-menthane-3,8-diol (II) in the presence of NADPH and O2. This activity was significantly higher in microsomes obtained from phenobarbital (PB)-induced rats than from control microsomal preparations, whereas 3-methylcholanthrene (3-MC)-induced microsomes failed to convert l-menthol to compound II in the presence of NADPH and O2. l-Menthol elicited a type I spectrum with control (Ks = 60.6 microM) and PB-induced (Ks = 32.3 microM) microsomes whereas with 3MC-induced microsomes it produced a reverse type I spectrum.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2906604

  6. Validation/Uncertainty Quantification for Large Eddy Simulations of the heat flux in the Tangentially Fired Oxy-Coal Alstom Boiler Simulation Facility

    Smith, P.J.; Eddings, E.G.; Ring, T.; Thornock, J.; Draper, T.; Isaac, B.; Rezeai, D.; Toth, P.; Wu, Y.; Kelly, K.

    2014-08-01

    The objective of this task is to produce predictive capability with quantified uncertainty bounds for the heat flux in commercial-scale, tangentially fired, oxy-coal boilers. Validation data came from the Alstom Boiler Simulation Facility (BSF) for tangentially fired, oxy-coal operation. This task brings together experimental data collected under Alstom’s DOE project for measuring oxy-firing performance parameters in the BSF with this University of Utah project for large eddy simulation (LES) and validation/uncertainty quantification (V/UQ). The Utah work includes V/UQ with measurements in the single-burner facility where advanced strategies for O2 injection can be more easily controlled and data more easily obtained. Highlights of the work include: • Simulations of Alstom’s 15 megawatt (MW) BSF, exploring the uncertainty in thermal boundary conditions. A V/UQ analysis showed consistency between experimental results and simulation results, identifying uncertainty bounds on the quantities of interest for this system (Subtask 9.1) • A simulation study of the University of Utah’s oxy-fuel combustor (OFC) focused on heat flux (Subtask 9.2). A V/UQ analysis was used to show consistency between experimental and simulation results. • Measurement of heat flux and temperature with new optical diagnostic techniques and comparison with conventional measurements (Subtask 9.3). Various optical diagnostics systems were created to provide experimental data to the simulation team. The final configuration utilized a mid-wave infrared (MWIR) camera to measure heat flux and temperature, which was synchronized with a high-speed, visible camera to utilize two-color pyrometry to measure temperature and soot concentration. • Collection of heat flux and temperature measurements in the University of Utah’s OFC for use is subtasks 9.2 and 9.3 (Subtask 9.4). Several replicates were carried to better assess the experimental error. Experiments were specifically designed for the

  7. Synthesis and preliminary evaluation of [123I]1-(4-cyanobenzyl)-4-[[(trans-iodopropen-2-yl)oxy]-methyl]piperidine: A novel high affinity sigma receptor radioligand for SPECT

    1-(4-Cyanobenzyl)-4-[[(trans-iodopropen-2-yl)oxy]methyl]piperidine (2) has been synthesized as a novel iodinated ligand for sigma receptors. This new compound exhibited high affinity (Ki = 0.38 nM) for the sigma-1 receptor and selectivity for sigma-1 vs. sigma-2 receptors (Ki σ-1/σ-2 0.02) using in vitro receptor binding assays. Moderate affinity for muscarinic M1 (K1 = 178 nM) receptors and low affinity (Ki = 1,460 nM) for dopamine D2 receptors was also noted. The lipophilicity of 2 (log P7.5 3.24) is moderate, indicating that the ligand should readily cross the blood/brain barrier. The corresponding radioiodinated ligand, 123I-2, was synthesized from the appropriate trans vinyl tributylstannane precursor under acidic conditions using oxidative iododestannylation methods. HPLC purification provided the radioligand in yields ranging between 63 and 75% EOS (n = 5) and with > 99% radiochemical purity and a specific activity > 77,000 MBq/μmol. Preliminary in vivo distribution and pharmacological blocking studies using 123I-2 were performed in male Australian Albino Wistar rats. 123I-2 exhibited good brain uptake (1.11 ± 0.14 %ID at 20 min PI) with no significant loss of radioactivity from the brain over the course of the study (4 h). The gross regional brain distribution of the radioligand showed highest uptake in the posterior cortex and frontal cortex, with slightly lower uptake in other brain regions examined. Most of the uptake of radioactivity in the brain, lung, heart, muscle, and kidney was prevented by pre-administration of compounds with affinity for sigma receptors, indicating the in vivo specificity of the ligand. In view of these results, 123I-2 shows promise for the in vivo tomographic evaluation of sigma receptor densities

  8. Direct observation of Nd3+ and Tm3+ ion distributions in oxy-fluoride glass ceramics containing PbF2 nanocrystals

    Nd3+ and Tm3+, doped oxy-fluoride glasses and glass ceramics were prepared by conventional melt-quenching and subsequent heat-treatment, respectively. β-PbF2 nanocrystals with diameter 50 –100 nm formed in the glass matrix after heat treatment. The Stark splitting in absorption peaks, enhanced photoluminescence and prolonged lifetimes that β-PbF2 nanocrystal formation increased the luminescence of rare earth ions. Both Nd3+ and Tm3+ ions were incorporated into nanocrystals that were enriched in lead and fluorine, and deficient in oxygen. - Highlights: • EELS analysis for rare-earth ion distribution in oxy-fluoride glass ceramics • No significant changes in lifetimes of Nd3+, while obvious change for Tm3+ • Direct evidence of Nd3+ and Tm3+ aggregation into fluoride nanocrystals

  9. (2E,6E)-2,6-Bis(2-fluoro-5-meth­oxy­benzyl­idene)cyclo­hexan-1-one

    Chen, Linfeng; Zhang, Li; Wang, Zhe; Wu, Yunjie; Liang, Guang

    2010-01-01

    The title compound, C22H20F2O3, a derivative of curcumin, crystallized with two independent mol­ecules in the asymmetric unit. The mean planes of the two 2-fluoro-5-meth­oxy­phenyl groups are aligned at 24.88 (11)° in one mol­ecule and 24.19 (15)° in the other. The dihedral angles between the mean plane of the penta-1,4-dien-3-one group and those of the two 2-fluoro-5-meth­oxy­phenyl rings are 51.16 (11) and 49.16 (10)° in the first mol­ecule, and 45.69 (15) and 54.00 (14)° in the second. The mol­ecules adopt E configurations about the central olefinic bonds. PMID:21589587

  10. 6-(4-Bromo­phen­yl)-2-eth­oxy-4-(4-ethoxy­phen­yl)nicotinonitrile

    Chantrapromma, Suchada; Fun, Hoong-Kun; Suwunwong, Thitipone; Padaki, Mahesh; Isloor, Arun M.

    2009-01-01

    The mol­ecule of the title nicotinonitrile derivative, C22H19BrN2O2, is non-planar, the central pyridine ring making dihedral angles of 7.34 (14) and 43.56 (15)° with the 4-bromo­phenyl and 4-ethoxy­phenyl rings, respectively. The eth­oxy group of the 4-ethoxy­phenyl is slightly twisted from the attached benzene ring [C—O—C—C = 174.2 (3)°], whereas the eth­oxy group attached to the pyridine ring is in a (+)syn-clinal conformation [C—O—C—C = 83.0 (3)°]. A weak intra­molecular C—H⋯N inter­actio...

  11. Thermodynamic and economic analysis of the different variants of a coal-fired, 460 MW power plant using oxy-combustion technology

    Highlights: • Mathematical models of an integrated oxy-combustion power plant. • Thermodynamic analysis of the modeled different cases of the plant. • Analysis of the methods of increasing the net efficiency of the plant. • Economic comparative analysis of the air-type and oxy-type plants. - Abstract: In the face of existing international provisions limiting the emissions of greenhouse gases, primarily carbon dioxide, it is necessary to introduce solutions that will allow the production of electricity from coal with high efficiency and low emissions. Oxy-combustion systems integrated with carbon capture and storage (CCS) installations may prove to be such a solution. This paper presents the main results from a thermodynamic analysis of a supercritical unit operating in oxy-combustion technology, fueled with pulverized coal with a power output of 460 MW. The parameters of the live steam in the analyzed system are 600 °C/30 MPa. To perform the numerical analyses, models of the individual components were built, including an oxygen production installation (ASU), a boiler, a steam cycle and a flue gas conditioning system (CPU). The models were built in the commercial programs GateCycle and Aspen and then integrated into the Excel environment. In this paper, different structures for an integrated oxy-type system were analyzed and compared. The auxiliary power rates were determined for individual technological installations of the oxy-combustion power plant. The highest value of this indicator, in the range between 15.65% and 19.10% was calculated for the cryogenic ASU. The total value of this index for the whole installation reaches as high as 35% for the base case. The use of waste heat from the interstage cooling of compressors in the air separation installation and flue gas conditioning system was considered as the methods of counteracting the efficiency decrease resulting from the introduction of ASU and CPU. The proposed configurations and optimization

  12. Different hydrogen-bonded structures in three 2-thienyl-substituted tetra­hydro-1,4-ep­oxy-1-benzazepines

    Blanco, Maria C.; Palma, Alirio; Bahsas, Ali; Cobo, Justo; Glidewell, Christopher

    2009-01-01

    The mol­ecules of (2RS,4SR)-2-exo-(5-bromo-2-thienyl)-7-chloro-2,3,4,5-tetra­hydro-1H-1,4-ep­oxy-1-benzazepine, C14H11BrClNOS, (I), are linked into cyclic centrosymmetric dimers by C—H⋯π(thienyl) hydrogen bonds. Each such dimer makes rather short Br⋯Br contacts with two other dimers. In (2RS,4SR)-2-exo-(5-methyl-2-thienyl)-2,3,4,5-tetra­hydro-1H-1,4-ep­oxy-1-benzazepine, C15H15NOS, (II), a com­bination of C—H⋯O and C—H⋯π(thienyl) hydrogen bonds links the mol­ecules into chains of rings. A mor...

  13. Energy and exergy analysis of chemical looping combustion technology and comparison with pre-combustion and oxy-fuel combustion technologies for CO2 capture

    Mukherjee, S.; Kumar, P.; Yang, A.; P. Fennell

    2015-01-01

    Abstract Carbon dioxide (CO2) emitted from conventional coal-based power plants is a growing concern for the environment. Chemical looping combustion (CLC), pre-combustion and oxy-fuel combustion are promising CO2 capture technologies which allow clean electricity generation from coal in an integrated gasification combined cycle (IGCC) power plant. This work compares the characteristics of the above three capture technologies to those of a conventional IGCC plant without CO2 capture. CLC tech...

  14. A comprehensive evaluation of different radiation models in a gas turbine combustor under conditions of oxy-fuel combustion with dry recycle

    Kez, V.; Liu, F.; Consalvi, J. L.; Ströhle, J.; Epple, B.

    2016-03-01

    The oxy-fuel combustion is a promising CO2 capture technology from combustion systems. This process is characterized by much higher CO2 concentrations in the combustion system compared to that of the conventional air-fuel combustion. To accurately predict the enhanced thermal radiation in oxy-fuel combustion, it is essential to take into account the non-gray nature of gas radiation. In this study, radiation heat transfer in a 3D model gas turbine combustor under two test cases at 20 atm total pressure was calculated by various non-gray gas radiation models, including the statistical narrow-band (SNB) model, the statistical narrow-band correlated-k (SNBCK) model, the wide-band correlated-k (WBCK) model, the full spectrum correlated-k (FSCK) model, and several weighted sum of gray gases (WSGG) models. Calculations of SNB, SNBCK, and FSCK were conducted using the updated EM2C SNB model parameters. Results of the SNB model are considered as the benchmark solution to evaluate the accuracy of the other models considered. Results of SNBCK and FSCK are in good agreement with the benchmark solution. The WBCK model is less accurate than SNBCK or FSCK. Considering the three formulations of the WBCK model, the multiple gases formulation is the best choice regarding the accuracy and computational cost. The WSGG model with the parameters of Bordbar et al. (2014) [20] is the most accurate of the three investigated WSGG models. Use of the gray WSSG formulation leads to significant deviations from the benchmark data and should not be applied to predict radiation heat transfer in oxy-fuel combustion systems. A best practice to incorporate the state-of-the-art gas radiation models for high accuracy of radiation heat transfer calculations at minimal increase in computational cost in CFD simulation of oxy-fuel combustion systems for pressure path lengths up to about 10 bar m is suggested.

  15. Application of oxy-combustion techniques in art glass industry; Application des technologies d'oxycombustion en verrerie d'art

    Vieville, G.; Choquenet, L. [Aga, France (France)

    2000-10-01

    Two innovating techniques of fusion and preheating based on oxy-combustion have recently been developed by the Linde group (industrial gas supplier: AGA) with glassmakers partners, with the aim to better product (energy conservation, lower cost) while respecting the new environmental standards. Concrete applications examples at the Biot glassmaking and at the Baccarat crystal manufacture have allowed to validate their performances at an industrial scale. (O.M.)

  16. SYNTHESIS AND CHARACTERIZATION OF LIQUID CRYSTALLINE MULTI-BLOCK COPOLYMERS,POLY[1,6-BIS(4-OXYBENZOYL-OXY)HEXANE TEREPHTHALATE]-b-BISPHENOL A POLYCARBONATE

    Hui-qing Zhang; Xiong-yan Zhao; De-shan Liu; Qi-xiang Zhou

    1999-01-01

    A series of liquid crystalline multi-block copolymers poly[1,6-bis(4-oxybenzoyl-oxy)hexane terephthalate]-b-bisphenol A polycarbonate (PHTH-6-b-PC) with different segment lengths were synthesized in tetrachloroethane by solution polycondensation in which hydroxyl terminated PC and acyl chloride terminated PHTH-6 were used. It is found that block copolymers with high molecular weight and welldefined structures were obtained. All the block copolymers exhibit a nematic liquid crystalline texture.

  17. Resolution of galactose, glucose, xylose and mannose in sugarcane bagasse employing a voltammetric electronic tongue formed by metals oxy-hydroxide/MWCNT modified electrodes

    Cardoso de Sá, Acelino; González-Calabuig, Andreu; Cipri, Andrea; Ramos Stradiotto, Nelson; Valle Zafra, Manuel del

    2016-01-01

    Second generation ethanol is produced from the carbohydrates released from the cell wall of bagasse and straw of sugarcane. The objective of this work is the characterization and application of a voltammetric electronic tongue using an array of glassy carbon electrodes modified with multi-walled carbon nanotubes containing metal (Paladium, Gold, Copper, Nickel and Cobalt) oxy-hydroxide nanoparticles (GCE/MWCNT/MetalsOOH) towards a simpler analysis of carbohydrates (glucose, xylose, galactose ...

  18. Study into mechanical and electrochemical properties of coating deposits and welded-coated components using the HVOF (High Velocity Oxy-Fuel) process.

    Boudi, Adnan Abdullatif

    2007-01-01

    The present study examines the metallurgical, mechanical and corrosion properties of High Velocity Oxy-Fuel (HVOF) thermal spray coatings of Inconel 625 powders on plain and welded surfaces of mild carbon and stainless steel (304). The research work carried out focused on coating adherence to base substrate, coating integrity and mechanical behavior of coating at the weld-substrate interface when subjected to tensile and fatigue loads. The solid bar and sheet specimens were tested and prepare...

  19. Design and development of a powder mixing device used in the deposition of high velocity oxy-fuel (HVOF) thermal spray functionally graded coatings; Kabir Al Mamun

    Al Mamun, Md. Kabir

    2007-01-01

    The application of Functionally Graded Materials (FGMs) is quite difficult, but thermal spray processes like Plasma spray have demonstrated their unique potential in producing graded deposits, where researchers have used twin powder feed systems to mix different proportions of powders. However the HVOF (High Velocity Oxy-Fuel) process does not possess this feature. FGMs vary in composition and/or microstructure from one boundary (substrate) to another (top service surface), and innovative cha...

  20. Numerical simulation of air and oxy-fuel combustion of single coal particles using the reactive implicit continuous-fluid Eulerian (RICE) method

    Lewtak, Robert

    2013-10-01

    The paper presents the mathematical model of air and oxy-fuel combustion of single coal particles. The combustion process has been treated as a spherically-symmetric one. The 1-dimensional time-dependent conservation equations governing the process have been numerically solved using the RICE method. The presence of a coal particle, which was treated as a discrete Lagrange particle, has modified the boundary conditions at the gas-solid interface. Numerical results show good agreement with the experimental results.

  1. Tailoring a High Temperature Corrosion Resistant FeNiCrAl for Oxy-Combustion Application by Thermal Spray Coating and HIP

    Jarkko Metsäjoki; Maria Oksa; Satu Tuurna; Juha Lagerbom; Jouko Virta; Sanni Yli-Olli; Tomi Suhonen

    2015-01-01

    Oxy-fuel combustion combined with CCS (carbon capture and storage) aims to decrease CO2 emissions in energy production using fossil fuels. Oxygen firing changes power plant boiler conditions compared to conventional firing. Higher material temperatures and harsher and more variable environmental conditions cause new degradation processes that are inadequately understood at the moment. In this study, an Fe-Ni-Cr-Al alloy was developed based on thermodynamic simulations. The chosen composition ...

  2. Scale formation on ferritic and austenitic steels in high CO2/H2O containing gases simulating oxy-fuel environments

    The oxy-fuel process represents a promising technology for CO2 capture from the exhaust gas in coal fired power plants. The principle of this process consists of burning coal with pure oxygen, a recirculation of the CO2 gas produced and finally a separation of the CO2 from the combustion gases, by various methods which are presently being developed. Depending on the actual process parameters used, a number of metallic heat exchanging components will in the oxy-fuel process be subjected to service environments containing high amounts of CO2 and water vapour. In the present study, the oxidation behaviour of selected commercial ferritic and austenitic steels was investigated in simulated oxy-fuel environments at temperatures in the range 550-650 C. Thereby, the behaviour of the materials in the simulated oxy-fuel gas was compared with that in CO2, H2O and CO2-O2. The experiments showed that ferritic steels components exposed to CO2/H2O gas mixtures, may exhibit substantially higher oxidation rates than during air exposure. The oxidation rates are similar to those observed in service environments of conventional power plants; however the steels exhibit a substantially larger tendency to carburization than in conventional service gases. Austenitic steels exposed to the CO2/H2O atmospheres exhibit oxidation and carburization rates which are strongly dependent on the actual Cr content of the steel and also on component surface preparation. The paper will discuss how the individual species present in the mixed gases affect the scale formation mechanisms especially in respect to their positive or adverse effect on formation of protective chromia base oxide scales. (authors)

  3. Microstructural characterisation of a high velocity oxy-fuel thermally sprayed Al-12wt.%Sn-1wt.%Cu alloy

    Kong, Chang-Jing; Brown, Paul D.; Horlock, Andrew J.; Harris, Sam J.; McCartney, D. Graham

    2001-01-01

    High velocity oxy-fuel thermal sprayed Al-12wt.%Sn-1wt.%Cu alloy coatings have been characterised both in the as-sprayed condition and following heat treatment in air at 300C for periods up to 5 hours. The as-sprayed microstructure comprises principally nanoscale Sn-rich particles embedded in an Al-rich matrix. The Sn-particles coarsen and the alloy microhardness decreases with increasing time of heat treatment.

  4. Kinetic models for the oxy-fuel combustion of coal and coal/biomass blend chars obtained in N2 and CO2 atmospheres

    The thermal reactivity and kinetics of five coal chars, a biomass char, and two coal/biomass char blends in an oxy-fuel combustion atmosphere (30%O2–70%CO2) were studied using the non-isothermal thermogravimetric method at three heating rates. Fuel chars were obtained by devolatilization in an entrained flow reactor at 1273 K under N2 and CO2 atmospheres. Three nth-order representative gas–solid models – the volumetric model (VM), the grain model (GM) and the random pore model (RPM) – were employed to describe the reactive behaviour of the chars. The RPM model was found to be the best for describing the reactivity of the high rank coal chars, while VM was the model that best described the reactivity of the bituminous coal chars, the biomass char and the coal-biomass blend char. The kinetic parameters of the chars obtained in N2 and CO2 in an oxy-fuel combustion atmosphere with 30% of oxygen were compared, but no relevant differences were observed. The behaviour of the blend of the bituminous coal (90%wt.) and the biomass (10%wt.) chars resembled that of the individual coal concealing the effect of the biomass. Likewise, no interaction was detected between the high rank coal and the biomass chars during oxy-fuel combustion of the blend. -- Highlights: ► Oxy-fuel reactivity and kinetics of coal and coal/biomass blends chars were determined. ► Kinetic parameters were essentially the same under N2 or CO2 devolatilization atmospheres. ► Best model for describing chars reactivity depended on the parent coal rank. ► Random pore model for low rank coal and biomass chars; volumetric model for high rank coal chars.

  5. Influence of pentavalent niobium doping on microstructure and electrical conductivity of oxy-apatite La10Si6O27 electrolytes

    Oxy-apatite type La10Si6–xNbxO27+δ ceramics doped with different pentavalent niobium contents are synthesized via the high-temperature solid state reaction method. Crystal structure and electrical properties of La10Si6–xNbxO27+δ ceramics are investigated by X-ray diffraction, scanning electron microscope, transmission electron microscope, Raman spectroscopy and complex impedance measurements. La10Si6O27 ceramic sintered at 1923 K consists of hexagonal oxy-apatite phase and a small amount of La2SiO5. Pentavalent niobium can partially substitute for tetravalent silicon to form a Nb-doped oxy-apatite structure. However, La2SiO5 phase disappears with increasing the pentavalent niobium content. Some fine La3NbO7 particles are found at grain boundaries of oxy-apatite phase in La10Si6–xNbxO27+δ ceramics when the pentavalent niobium content is beyond 0.1. Raman spectra of La10Si6–xNbxO27+δ ceramics generates three new characteristic modes at 710 cm−1, 342 cm−1 and 136 cm−1 with the addition of different pentavalent niobium contents, which are significantly enhanced especially at x = 0.1 and x = 0.5. These new modes are from Nb−O bonds of La3NbO7 phase and obstruct the interstitial oxide-ion O(5) from conducting in dry atmosphere, thus the grain boundary impedance of La10Si6–xNbxO27+δ ceramics increases correspondingly. La10Si5.9Nb0.1O27.05 ceramic exhibits the highest total conductivity among all the compositions above 873 K

  6. Tailoring a High Temperature Corrosion Resistant FeNiCrAl for Oxy-Combustion Application by Thermal Spray Coating and HIP

    Jarkko Metsäjoki

    2015-10-01

    Full Text Available Oxy-fuel combustion combined with CCS (carbon capture and storage aims to decrease CO2 emissions in energy production using fossil fuels. Oxygen firing changes power plant boiler conditions compared to conventional firing. Higher material temperatures and harsher and more variable environmental conditions cause new degradation processes that are inadequately understood at the moment. In this study, an Fe-Ni-Cr-Al alloy was developed based on thermodynamic simulations. The chosen composition was manufactured as powder by gas atomization. The powder was sieved into two fractions: The finer was used to produce thermal spray coatings by high velocity oxy-fuel (HVOF and the coarser to manufacture bulk specimens by hot isostatic pressing (HIP. The high temperature corrosion properties of the manufactured FeNiCrAl coating and bulk material were tested in laboratory conditions simulating oxy-combustion. The manufacturing methods and the results of high temperature corrosion performance are presented. The corrosion performance of the coating was on average between the bulk steel references Sanicro 25 and TP347HFG.

  7. Performance analyses of oxy-fuel power generation systems including CO2 capture: comparison of two cycles using different recirculation fluids

    With increasing concerns on global warming, reduction of CO2 emission has become a hot issue and studies of CO2 capture and storage (CCS) technology in power plant applications are in progress. Oxy-fuel combustion is one of the several available technologies that intend to capture CO2. Since the combustion gas consists mainly of CO2 and H2O in oxy-fuel combustion systems, it is easy to separate CO2 from the flue gas using a simple mechanical method instead of complex chemical processes. There have been suggested a couple of power cycles using different recirculation fluids for combustion dilution purpose. This study aimed to investigate the influence of CO2 capture on the performance of two promising oxy-fuel combustion power cycles adopting H2O and CO2 as the recirculation fluid. Optimal integration between the carbon capture process and the power cycle was examined and the influences of carbon capture on the entire system performance were compared for the two cycles

  8. Performance Analysis of an Oxy-fuel Combustion Power Generation System Based on Waste heat Recovery:influence of CO2 Capture

    As the global warming becomes a serious environmental problem, studies of reducing CO2 emission in power generation area are in progress all world. One of the carbon capture and storage(CCS) technologies is known as oxy-fuel combustion power generation system. in the oxy-fuel combustion system, the exhaust gas is mainly composed of CO2 and H2O. Thus, high-purity CO2 can be obtained after a proper H2O removal process. In this paper, an oxy-fuel combustion cycle that recovers the waste heat of a high-temperature fuel cell is analyzed thermodynamically. Variations of characteristics of CO2 and H2O mixture which is extracted from the condenser and power consumption required to obtain highly-pure CO2 gas were examined according to the variation of the condensing pressure. The influence of the number of compression stages on the power consumption of the CO2 capture process was analyzed, and the overall system performance was also investigated

  9. A comprehensive evaluation of the influence of air combustion and oxy-fuel combustion flue gas constituents on Hg(0) re-emission in WFGD systems.

    Ochoa-González, Raquel; Díaz-Somoano, Mercedes; Martínez-Tarazona, M Rosa

    2014-07-15

    This paper evaluates the influence of the main constituents of flue gases from coal combustion (CO2, O2, N2 and water vapor), in air and oxy-fuel combustion conditions on the re-emission of Hg(0) in wet scrubbers. It was observed that the concentration of water vapor does not affect the re-emission of mercury, whereas O2 and CO2 have a notable influence. High concentrations of O2 in the flue gas prevent the re-emission of Hg(0) due to the reaction of oxygen with the metals present in low oxidation states. High concentrations of CO2, which cause a decrease in the pH and the redox potential of gypsum slurries, reduce the amount of Hg(0) that is re-emitted. As a consequence, the high content of CO2 in oxy-fuel combustion may decrease the re-emission of Hg(0) due to the solubility of CO2 in the suspension and the decrease in the pH. It was also found that O2 affects the stabilization of Hg(2+) species in gypsum slurries. The results of this study confirm that the amount of metals present in limestone as well as the redox potential and pH of the slurries in wet desulphurization plants need to be strictly controlled to reduce Hg(0) re-emissions from power plants operating under oxy-fuel combustion conditions. PMID:24887118

  10. Effect of Oxymatrine on Learning and Memory of Epileptic Rats and the Expression of p -JNK in Hippocampus%氧化苦参碱对青霉素致痫大鼠学习记忆及海马p-JNK表达的影响

    杨文谦; 刘红梅; 赵衍; 陈晓霞; 张荣华; 白洁

    2011-01-01

    Objective To observe the effect of oxymatrine on the expression of p - JNK in hippocampus and the spatial learning and memory of penicillin - induced epileptic rats, as well as to investigate its mechanisms.Methods 24 SD rats were randomly divided into four groups, which were normal saline control group (NS) ,epilepsy group ( EP), Oxymatraine group ( OXY ) and JNK inhibitor group ( SP600125, SP ).Penicillin was intraperitoneally injected in rats to establish epileptic animal model.Behavioral changes were observed and immunohistochemical method was used to measure the number of positive - cell of p - JNK in hippocampus.The spatial learning and memory was tested by Morris Water Maze (MWM).Results Compared with in EP group, the escape latency, swimming distance, times of crossing platform in OXY group were significantly descreased ( P < 0.05 ); the expression of p - JNK was less in OXY group than that in EP group ( P < 0.05 ).Conclusion The protection of OXY for the spatial learning and memory in epileptic rats is performed by affecting the activation of JNK signaling pathway.%目的 观察氧化苦参碱(Oxymatrine,OXY)对青霉素(Penicillin,PEN)致痫大鼠学习记忆和海马神经元p-JNK表达的影响.方法 成年SD大鼠24只随机分为生理盐水对照组(Normal saline,NS)、癫痫模型组(Epilepsy,EP)、OXY组和JNK抑制剂组(SP600125,SP),腹腔注射青霉素诱导大鼠癫痫发作,观察大鼠行为学改变,Morris水迷宫检测大鼠空间学习和记忆,免疫组化测定海马组织内p-JNK阳性细胞数.结果 与EP组对比,OXY组大鼠逃避潜伏期和穿越平台次数明显减少(P<0.05);海马组织内p-JNK阳性细胞数明显降低(P<0.05).结论 OXY可能通过抑制JNK信号通路的活化发挥对癫痫大鼠在空间学习和记忆方面的保护作用.

  11. Oxy-fuel combustion kinetics and morphology of coal chars obtained in N2 and CO2 atmospheres in an entrained flow reactor

    Highlights: ►Char reactivity in oxy-fuel conditions is essential for industrial scale designing. ► Kinetics of coal chars obtained in N2 and CO2 were determined under 30%O2–70%CO2. ► The best model for describing the oxy-fuel combustion of coal chars was the RPM. ► CO2 chars showed higher volatile yield and slightly lower reactivity than N2 chars. -- Abstract: The thermal reactivity and kinetics of four coal chars (HVN, UM, SAB and BA) in an oxy-fuel combustion atmosphere (30%O2–70%CO2) were studied using a thermobalance. The coal chars were obtained by devolatilization in an entrained flow reactor (EFR) at 1000 °C for 2.5 s under 100% N2 and CO2 atmospheres. The reactivity tests were carried out by isothermal thermogravimetric analysis at different temperatures in a kinetically controlled regime. Three nth-order representative gas–solid models – the volumetric model (VM), the grain model (GM) and the random pore model (RPM) – were employed in order to describe the reactive behaviour of the chars during oxy-fuel combustion. From these models, the kinetic parameters were determined. The RPM model was found to be the best for describing the reactivity of the HVN, UM and BA chars, while VM was the model that best described the reactivity of the SAB char. The reactivities of the chars obtained in N2 and CO2 in an oxy-fuel combustion atmosphere with 30% of oxygen were compared using the kinetic parameters, but no differences were observed between the two devolatilization atmospheres. The apparent volatile yield after the coal devolatilization under CO2 in the EFR was greater than under N2 for all the coals studied. According to the scanning electron microscopy (SEM) images of the chars, those obtained in the CO2 atmosphere experienced a greater degree of swelling, some particles showing partially reacted surfaces indicative of reaction between the char and CO2.

  12. Crystal structures of (Z)-5-[2-(benzo[b]thio-phen-2-yl)-1-(3,5-di-meth-oxy-phen-yl)ethen-yl]-1H-tetra-zole and (Z)-5-[2-(benzo[b]thio-phen-3-yl)-1-(3,4,5-tri-meth-oxy-phen-yl)ethen-yl]-1H-tetra-zole.

    Penthala, Narsimha Reddy; Yadlapalli, Jaishankar K B; Parkin, Sean; Crooks, Peter A

    2016-05-01

    (Z)-5-[2-(Benzo[b]thio-phen-2-yl)-1-(3,5-di-meth-oxy-phen-yl)ethen-yl]-1H-tetrazole methanol monosolvate, C19H16N4O2S·CH3OH, (I), was prepared by the reaction of (Z)-3-(benzo[b]thio-phen-2-yl)-2-(3,5-di-meth-oxy-phen-yl)acrylo-nitrile with tri-butyl-tin azide via a [3 + 2]cyclo-addition azide condensation reaction. The structurally related compound (Z)-5-[2-(benzo[b]thio-phen-3-yl)-1-(3,4,5-tri-meth-oxy-phen-yl)ethen-yl]-1H-tetra-zole, C20H18N4O3S, (II), was prepared by the reaction of (Z)-3-(benzo[b]thio-phen-3-yl)-2-(3,4,5-tri-meth-oxy-phen-yl)acrylo-nitrile with tri-butyl-tin azide. Crystals of (I) have two mol-ecules in the asymmetric unit (Z' = 2), whereas crystals of (II) have Z' = 1. The benzo-thio-phene rings in (I) and (II) are almost planar, with r.m.s deviations from the mean plane of 0.0084 and 0.0037 Å in (I) and 0.0084 Å in (II). The tetra-zole rings of (I) and (II) make dihedral angles with the mean planes of the benzo-thio-phene rings of 88.81 (13) and 88.92 (13)° in (I), and 60.94 (6)° in (II). The di-meth-oxy-phenyl and tri-meth-oxy-phenyl rings make dihedral angles with the benzo-thio-phene rings of 23.91 (8) and 24.99 (8)° in (I) and 84.47 (3)° in (II). In both structures, mol-ecules are linked into hydrogen-bonded chains. In (I), these chains involve both tetra-zole and methanol, and are parallel to the b axis. In (II), mol-ecules are linked into chains parallel to the a axis by N-H⋯N hydrogen bonds between adjacent tetra-zole rings. PMID:27308011

  13. Effects of oxyR Regulon, the Bacterial Antioxidant Defense on Escherichia coil's Growth and Reproduction%大肠杆菌抗氧化系统-oxyR调节子对细菌生长繁殖的调控作用

    李欣; 王利平; 杜琳; 杨丽鹏; 乔家驹; 李红玉; 冯汉青

    2014-01-01

    oxyR调节子是最早发现的细菌抗氧化防御系统之一,大肠杆菌oxyR调节子中参与抗氧化作用的基因成员包括katG、ahpC、ahpF等,通过对H2O2及过氧化物等的直接清除方式发挥作用.虽然该方面的研究很多,但对于大肠杆菌oxyR调节子对细菌生长繁殖的影响尚不清楚.通过对大肠杆菌oxyR、ahpCF、katE/G基因突变菌株进行研究,突变体JI370中ahpCF基因缺失导致其内源H2O2积累减少使其生长相应加快,而对于katG和katE基因突变体JI367和ahpCF、oxyR基因突变体LC74来说,胞内H2O2极显著上升会抑制细菌生长,并且H2O2积累量越大对其生长抑制作用越明显.与野生型菌株相比,ahpCF的缺失突变菌株JI370和ahpCF及oxyR双突变的LC74在菌株生长的潜伏期受到更显著的影响.结果表明:在CAT (catalase,CAT)与AHP (alkyl hydroperoxide reductase,AHP)协同清除内源H2O2的作用中,AHP起到主导作用,并且在细菌的生长繁殖中,ahp基因起到重要的作用.

  14. α-Tocopherol impact on oxy-radical induced free radical decomposition of DMSO: Spin trapping EPR and theoretical studies

    Graphical abstract: α-Tocopherol inhibits the oxidation of ·CH3 to ·OCH3. Display Omitted Highlights: → α-Tocopherol does not inhibit the oxidation of DMSO to ·CH3. → α-Tocopherol inhibits the oxidation of ·CH3 to ·OCH3. → α-Tocopherol does not inhibit the oxidation of PBN. → The structures of observed spin adducts were theoretically confirmed. - Abstract: EPR spin trapping and theoretical methods such as density functional theory (DFT) as well as combined DFT and quadratic configuration interaction approach (DFT/QCISD) were used to identify the radicals produced in the reaction of oxy-radicals and dimethyl sulfoxide (DMSO) in the presence and absence of α-tocopherol. Additionally, the mixtures of α-tocopherol with linolenic acid and glyceryl trilinoleate as well as bioglycerols (glycerol fractions from biodiesel production) were tested. α-Tocopherol inhibited oxidation of the main decomposition product of DMSO, ·CH3 to ·OCH3 but did not prevent the transformation process of N-t-butyl-α-phenylnitrone (PBN) into 2-methyl-2-nitrosopropane (MNP). Theoretical investigations confirmed the structures of proposed spin adducts and allowed to correlate the EPR parameters observed in the experiment with the spin adducts electronic structure.

  15. Experimental study on the minimum ignition temperature of coal dust clouds in oxy-fuel combustion atmospheres.

    Wu, Dejian; Norman, Frederik; Verplaetsen, Filip; Van den Bulck, Eric

    2016-04-15

    BAM furnace apparatus tests were conducted to investigate the minimum ignition temperature of coal dusts (MITC) in O2/CO2 atmospheres with an O2 mole fraction from 20 to 50%. Three coal dusts: Indonesian Sebuku coal, Pittsburgh No.8 coal and South African coal were tested. Experimental results showed that the dust explosion risk increases significantly with increasing O2 mole fraction by reducing the minimum ignition temperature for the three tested coal dust clouds dramatically (even by 100°C). Compared with conventional combustion, the inhibiting effect of CO2 was found to be comparatively large in dust clouds, particularly for the coal dusts with high volatile content. The retardation effect of the moisture content on the ignition of dust clouds was also found to be pronounced. In addition, a modified steady-state mathematical model based on heterogeneous reaction was proposed to interpret the observed experimental phenomena and to estimate the ignition mechanism of coal dust clouds under minimum ignition temperature conditions. The analysis revealed that heterogeneous ignition dominates the ignition mechanism for sub-/bituminous coal dusts under minimum ignition temperature conditions, but the decrease of coal maturity facilitates homogeneous ignition. These results improve our understanding of the ignition behaviour and the explosion risk of coal dust clouds in oxy-fuel combustion atmospheres. PMID:26799218

  16. [The study of up-conversion fluorescence in Er3+:Yb3+ co-doped oxy-fluoride glasses].

    Yang, Xiao-liang; Liu, Zheng-wei; Xiao, Si-guo

    2002-06-01

    Er3+:Yb3+ co-doped oxy-fluoride glasses with composition of (50-x) GeO2.PbF2.WO3.(6 + x) CdF2.1.4Yb2O3.0.6Er2O3 (x = 10,20,30) were prepared. Their up-conversion fluorescence characteristics were investigated under excitation of 930 nm diode laser. Three strong fluorescence bands of Er3+ whose central wavelength lie in 543, 550 and 655 nm have been observed. The maximum phonon energy is obtained by measuring anti-stokes Raman shifts of the samples, and the up-conversion mechanism is briefly discussed. The influences of host materials composition on up-conversion efficiency are also discussed adopting the average electronegative difference and the cationic field strength of the host. It is found that relative small average electronegative difference and large cationic field strength of host benefit to energy up-conversion. PMID:12938302

  17. Hybrid membrane/cryogenic separation of oxygen from air for use in the oxy-fuel process

    The process of oxy-fuel combustion requires the separation of oxygen from air on a large scale for use in the combustion chamber. This separation is currently done through energy intensive cryogenic distillation. To reduce the overall energy requirements for air separation it is examined whether a hybrid membrane and cryogenic process be utilized instead. The examined process uses an O2/N2 permeable membrane to create oxygen enriched air. This enriched air is then turned into high purity oxygen using cryogenic distillation. Several arrangements of such a system are investigated and compared on a practical and thermodynamic level to the current cryogenic process in use. It is found that using a vacuum pump arrangement to draw air through the membrane has potential to reduce energy requirements from the current standard. It is also found that the hybrid system is more productive in small to medium scale applications than in large scale applications because of the increased irreversibilities in the cryogenic process at smaller scales.

  18. Technology of oxygen production in the membranecryogenic air separation system for a 600 MW oxy-type pulverized bed boiler

    Berdowska, Sylwia; Skorek-Osikowska, Anna

    2012-09-01

    In this paper the results of the thermodynamic analysis of the oxy-combustion type pulverized bed boiler integrated with a hybrid, membrane- cryogenic oxygen separation installation are presented. For the calculations a 600 MW boiler with live steam parameters at 31.1 MPa /654.9 oC and reheated steam at 6.15 MPa/672.4 oC was chosen. In this paper the hybrid membrane-cryogenic technology as oxygen production unit for pulverized bed boiler was proposed. Such an installation consists of a membrane module and two cryogenic distillation columns. Models of these installations were built in the Aspen software. The energy intensity of the oxygen production process in the hybrid system was compared with the cryogenic technology. The analysis of the influence of membrane surface area on the energy intensity of the process of air separation as well as the influence of oxygen concentration at the inlet to the cryogenic installation on the energy intensity of a hybrid unit was performed.

  19. Identification of redox-sensitive cysteines in the arabidopsis proteome using OxiTRAQ, a quantitative redox proteomics method

    Liu, Pei

    2014-01-28

    Cellular redox status plays a key role in mediating various physiological and developmental processes often through modulating activities of redox-sensitive proteins. Various stresses trigger over-production of reactive oxygen/nitrogen species which lead to oxidative modifications of redox-sensitive proteins. Identification and characterization of redox-sensitive proteins are important steps toward understanding molecular mechanisms of stress responses. Here, we report a high-throughput quantitative proteomic approach termed OxiTRAQ for identifying proteins whose thiols undergo reversible oxidative modifications in Arabidopsis cells subjected to oxidative stress. In this approach, a biotinylated thiol-reactive reagent is used for differential labeling of reduced and oxidized thiols. The biotin-tagged peptides are affinity purified, labeled with iTRAQ reagents, and analyzed using a paralleled HCD-CID fragmentation mode in an LTQ-Orbitrap. With this approach, we identified 195 cysteine-containing peptides from 179 proteins whose thiols underwent oxidative modifications in Arabidopsis cells following the treatment with hydrogen peroxide. A majority of those redox-sensitive proteins, including several transcription factors, were not identified by previous redox proteomics studies. This approach allows identification of the specific redox-regulated cysteine residues, and offers an effective tool for elucidation of redox proteomes. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. (2E)-2-(4-Hy­droxy-3-meth­oxy­benzyl­idene)hydrazinecarboxamide

    Tahir, M. Nawaz; Ali, Akbar; Umar, M. Naveed; Hussain, Ishtiaq; Shad, Hazoor Ahmad

    2012-01-01

    In the title compound, C9H11N3O3, two mol­ecules are present in the asymmetric unit in which the 4-hy­droxy-3-meth­oxy­benzaldehyde and hydrazinecarboxamide units are almost planar [with r.m.s. deviations 0.0212 and 0.0066 Å, respectively, in one mol­ecule and 0.0346 and 0.0095 Å, respectively, in the other] and are oriented at dihedral angles of 9.7 (3) and 16.6 (3)°. In both mol­ecules, two S(5) ring motifs are present due to N—H⋯N and O—H⋯O hydrogen bonds. In the crystal, the mol­ecules are dimerized with each other due to pairs of N—H⋯O hydrogen bonds, forming an R 2 2(8) ring motif. O—H⋯O hydrogen bonds lead to the formation of a three-dimensional network. PMID:22807892

  1. Development of a Novel Oxygen Supply Process and its Integration with an Oxy-Fuel Coal-Fired Boiler

    None

    2006-12-31

    BOC, the world's second largest industrial gas company, has developed a novel high temperature sorption based technology referred to as CAR (Cyclic Autothermal Recovery) for oxygen production and supply to oxy-fuel boilers with flue gas recycle. This technology is based on sorption and storage of oxygen in a fixed bed containing mixed ionic and electronic conductor materials. The objective of the proposed work was to construct a CAR PDU that was capable of producing 10-scfm of oxygen, using steam or recycled flue gas as the sweep gas, and install it in the Combustion Test Facility. The unit was designed and fabricated at BOC/The Linde Group, Murray Hill, New Jersey. The unit was then shipped to WRI where the site had been prepared for the unit by installation of air, carbon dioxide, natural gas, nitrogen, computer, electrical and infrastructure systems. Initial experiments with the PDU consisted of flowing air into both sides of the absorption systems and using the air heaters to ramp up the bed temperatures. The two beds were tested individually to operational temperatures up to 900 C in air. The cycling process was tested where gases are flowed alternatively from the top then bottom of the beds. The PDU unit behaved properly with respect to flow, pressure and heat during tests. The PDU was advanced to the point where oxygen production testing could begin and integration to the combustion test facility could occur.

  2. A novel ion transport membrane reactor for fundamental investigations of oxygen permeation and oxy-combustion under reactive flow conditions

    Kirchen, Patrick

    2013-01-01

    Ion transport membrane (ITM) reactors present an attractive technology for combined air separation and fuel conversion in applications such as syngas production, oxidative coupling or oxy-combustion, with the promise of lower capital and operating costs, as well higher product selectivities than traditional technologies. The oxygen permeation rate through a given ITM is defined by the membrane temperature and oxygen chemical potential difference across it. Both of these parameters can be strongly influenced by thermochemical reactions occurring in the vicinity of the membrane, though in the literature they are often characterized in terms of the well mixed product stream at the reactor exit. This work presents the development of a novel ITM reactor for the fundamental investigation of the coupling between fuel conversion and oxygen permeation under well defined fluid dynamic and thermodynamic conditions, including provisions for spatially resolved, in-situ investigations. A planar, finite gap stagnation flow reactor with optical and probe access to the reaction zone is used to facilitate in-situ measurements and cross-validation with detailed numerical simulations. Using this novel reactor, baseline measurements are presented to elucidate the impact of the sweep gas fuel (CH4) fraction on the oxygen permeation and fuel conversion. In addition, the difference between well-mixed gas compositions measured at the reactor outlet and those measured in the vicinity of the membrane surface are discussed, demonstrating the unique utility of the reactor. © 2012 The Combustion Institute. Published by Elsevier Inc. All rights reserved.

  3. Hot corrosion of nanostructured CoNiCrAlYSi coatings deposited by high velocity oxy fuel process

    Highlights: • Hot corrosion of a nanostructured MCrAlY coating was studied. • Cryomilling was used to prepare nanostructured powders. • The corrosion improvement was attributed to α-Al2O3 particles. -- Abstract: This paper focuses on the structure and cyclic hot corrosion behavior of nanostructured MCrAlY coatings used in thermal barrier coatings of gas turbines as the bond coat. Cryomilling in a liquid nitrogen environment was used to prepare nanostructured CoNiCrAlYSi powders, as characterized by scanning electron microscopy and X-ray diffraction. Also, the long-term hot corrosion resistance of the coating deposited by high velocity oxy fuel thermal spraying of the cryomilled powders was studied in a molten salt medium of Na2SO4–Na2VO3 at 880 °C up to 640 h. According to the results, the cryomilling process improved the corrosion resistance of the nanostructured coating, as compared with coarse-grained CoNiCrAlYSi coatings. This improvement was attributed to some α-Al2O3 particles dispersed in the structure, created by cryomilling, and high-diffusivity paths, created by nanocrystallization, which favors the formation of a continuous α-Al2O3 barrier layer on the top of the coating

  4. Analytical and mechanical testing of high velocity oxy-fuel thermal sprayed and plasma sprayed calcium phosphate coatings.

    Haman, J D; Chittur, K K; Crawmer, D E; Lucas, L C

    1999-01-01

    Plasma spraying (PS) is the most frequently used coating technique for implants; however, in other industries a cheaper, more efficient process, high-velocity oxy-fuel thermal spraying (HVOF), is in use. This process provides higher purity, denser, more adherent coatings than plasma spraying. The primary objective of this work was to determine if the use of HVOF could improve the mechanical properties of calcium phosphate coatings. Previous studies have shown that HVOF calcium phosphate coatings are more crystalline than plasma sprayed coatings. In addition, because the coatings are exposed to more complex loading profiles in vivo than standard ASTM tensile tests provide, a secondary objective of this study was to determine the applicability of four-point bend testing for these coatings. Coatings produced by HVOF and PS were analyzed by profilometry, diffuse reflectance Fourier transform infrared spectroscopy, X-ray diffraction, four-point bend, and ASTM C633 tensile testing. HVOF coatings were found to have lower amorphous calcium phosphate content, higher roughness values, and lower ASTM C633 bond strengths than PS coatings; however, both coatings had similar crystal unit cell sizes, phases present (including hydroxyapatite, beta-tricalcium phosphate, and tetracalcium phosphate), and four-point bend bond strengths. Thus, the chemical, structural, and mechanical results of this study, in general, indicate that the use of HVOF to produce calcium phosphate coatings is equivalent to those produced by plasma spraying. PMID:10556851

  5. Tantalum (oxy)nitrides prepared using reactive sputtering for new nonplatinum cathodes of polymer electrolyte fuel cell

    Tantalum (oxy)nitrides (TaOxNy) have been investigated as new cathodes for polymer electrolyte fuel cells without platinum. TaOxNy films were prepared using a radio frequency magnetron sputtering under Ar + O2 + N2 atmosphere at substrate temperatures from 50 to 800 deg. C. The effect of the substrate temperature on the catalytic activity for the oxygen reduction reaction (ORR) and properties of the TaOxNy films were examined. The catalytic activity of the TaOxNy for the ORR increased with the increasing substrate temperature. The ORR current density at 0.4 V vs. RHE on TaOxNy prepared at 800 deg. C was approximately 20 times larger than that on TaOxNy prepared at 50 deg. C. The onset potential of the TaOxNy for the ORR was obtained at the ORR current density of -0.2 μA cm-2. The onset potential of the TaOxNy prepared at 800 deg. C was ca. 0.75 V vs. RHE. The X-ray diffraction patterns revealed that Ta3N5 structure grew as the substrate temperature increased. While, the ionization potentials of all specimens were lower than that of Ta3N5, and decreased with the increasing substrate temperature. The TaOxNy which had Ta3N5 structure and lower ionization potential might have a definite catalytic activity for the ORR

  6. Hot corrosion of nanostructured CoNiCrAlYSi coatings deposited by high velocity oxy fuel process

    Yaghtin, A.H., E-mail: yaghtin@gmail.com; Javadpour, S.; Shariat, M.H.

    2014-01-25

    Highlights: • Hot corrosion of a nanostructured MCrAlY coating was studied. • Cryomilling was used to prepare nanostructured powders. • The corrosion improvement was attributed to α-Al{sub 2}O{sub 3} particles. -- Abstract: This paper focuses on the structure and cyclic hot corrosion behavior of nanostructured MCrAlY coatings used in thermal barrier coatings of gas turbines as the bond coat. Cryomilling in a liquid nitrogen environment was used to prepare nanostructured CoNiCrAlYSi powders, as characterized by scanning electron microscopy and X-ray diffraction. Also, the long-term hot corrosion resistance of the coating deposited by high velocity oxy fuel thermal spraying of the cryomilled powders was studied in a molten salt medium of Na{sub 2}SO{sub 4}–Na{sub 2}VO{sub 3} at 880 °C up to 640 h. According to the results, the cryomilling process improved the corrosion resistance of the nanostructured coating, as compared with coarse-grained CoNiCrAlYSi coatings. This improvement was attributed to some α-Al{sub 2}O{sub 3} particles dispersed in the structure, created by cryomilling, and high-diffusivity paths, created by nanocrystallization, which favors the formation of a continuous α-Al{sub 2}O{sub 3} barrier layer on the top of the coating.

  7. Impurity impacts on the purification process in oxy-fuel combustion based CO2 capture and storage system

    Based on the requirements of CO2 transportation and storage, non-condensable gases, such as O2, N2 and Ar should be removed from the CO2-stream captured from an oxy-fuel combustion process. For a purification process, impurities have great impacts on the design, operation and optimization through their impacts on the thermodynamic properties of CO2-streams. Study results show that the increments of impurities will make the energy consumption of purification increase; and make CO2 purity of separation product and CO2 recovery rate decrease. In addition, under the same operating conditions, energy consumptions have different sensitivities to the variation of the impurity mole fraction of feed fluids. The isothermal compression work is more sensitive to the variation of SO2; while the isentropic compression work is more sensitive to the variation of Ar. In the flash system, the energy consumption of condensation in is more sensitive to the variation of Ar; but in the distillation system, the energy consumption of condensation is more sensitive to the variation of SO2, and CO2 purity of separation is more sensitive to the variation of SO2

  8. Fine particle collection of an electrostatic precipitator in CO2-rich gas conditions for oxy-fuel combustion.

    Han, Bangwoo; Kim, Hak Joon; Kim, Yong Jin

    2010-10-01

    The collection of particles in CO(2)-enriched environments has long been important for the capture of CO(2) in order to clean gases via oxy-fuel combustion. We here report on the collection characteristics of fine and ultrafine particles using an electrostatic precipitator (ESP) in a CO(2)-enriched atmosphere. In order to understand the characteristics of particle collection in CO(2)-rich gas mixtures, the ionic properties of a CO(2)-enriched atmosphere was also investigated. The electrical mobility of the ions in a CO(2)-enriched atmosphere was found to be about 0.56 times that found in a conventional air atmosphere, due to the higher mass of CO(2) gas compared to that of air. The low electrical mobility of ions resulted in a low corona current under CO(2)-enriched conditions. The collection efficiency of particles in a CO(2)-rich atmosphere for a given power consumption was thus somewhat lower than that found in air, due to the low quantity of particle charging in CO(2)-enriched air. At the same time, higher temperatures led to the higher electrical mobility of ions, which resulted in a greater collection efficiency for a given power. The presence of a negative corona also led to a greater collection efficiency of particles in an ESP than that achieved for a positive corona. PMID:20692021

  9. Influence of Processing Parameters on Residual Stress of High Velocity Oxy-Fuel Thermally Sprayed WC-Co-Cr Coating

    Gui, M.; Eybel, R.; Asselin, B.; Radhakrishnan, S.; Cerps, J.

    2012-10-01

    Residual stress in high velocity oxy-fuel (HVOF) thermally sprayed WC-10Co-4Cr coating was studied based on design of experiment (DOE) with five factors of oxygen flow, fuel gas hydrogen flow, powder feed rate, stand-off distance, and surface speed of substrate. In each DOE run, the velocity and temperature of in-flight particle in flame, and substrate temperature were measured. Almen-type N strips were coated, and their deflections after coating were used for evaluation of residual stress level in the coating. The residual stress in the coating obtained in all DOE runs is compressive. In the present case of HVOF thermally sprayed coating, the residual stress is determined by three types of stress: peening, quenching, and cooling stress generated during spraying or post spraying. The contribution of each type stress to the final compressive residual stress in the coating depends on material properties of coating and substrate, velocity and temperature of in-flight particle, and substrate temperature. It is found that stand-off distance is the most important factor to affect the final residual stress in the coating, following by two-factor interaction of oxygen flow and hydrogen flow. At low level of stand-off distance, higher velocity of in-flight particle in flame and higher substrate temperature post spraying generate more peening stress and cooling stress, resulting in higher compressive residual stress in the coating.

  10. Characterization of the bone-like apatite precipitated on high velocity oxy-fuel (HVOF) sprayed calcium phosphate deposits.

    Khor, K A; Li, H; Cheang, P

    2003-02-01

    Bone-like apatite was precipitated on the surface of thermal sprayed calcium phosphate coatings following in vitro incubation in a simulated body fluid. The coatings were initially deposited on titanium alloy substrates by the high velocity oxy-fuel (HVOF) spray technique. Structural characterization and mechanical evaluation of the precipitated apatite layer were conducted. Results showed that the precipitation rate was directly influenced by the local Ca(2+) concentration in the vicinity of the coating's surface and that preferential dissolution of certain phases was found to accelerate the precipitation of the bone-like apatite. The dense precipitates exhibited a competitive Young's modulus value of approximately 120GPa, which was obtained through nanoindentation. This compared favorably to the calcium phosphate matrix. Differences in microstructure at various locations within the layer resulted in altered Young's modulus and microhardness values. Precipitation mechanism investigation was carried out through a comparative experiment. Chemical analysis showed that the precipitation of bone-like apatite on the calcium phosphate coating was quite conceivably a partial diffusion-controlled process. PMID:12485795

  11. Impurity impacts on the purification process in oxy-fuel combustion based CO2 capture and storage system

    Based on the requirements of CO2 transportation and storage, non-condensable gases, such as O2, N2 and Ar should be removed from the CO2-stream captured from an oxy-fuel combustion process. For a purification process, impurities have great impacts on the design, operation and optimization through their impacts on the thermodynamic properties of CO2-streams. Study results show that the increments of impurities will make the energy consumption of purification increase; and make CO2 purity of separation product and CO2 recovery rate decrease. In addition, under the same operating conditions, energy consumptions have different sensitivities to the variation of the impurity mole fraction of feed fluids. The isothermal compression work is more sensitive to the variation of SO2; while the isentropic compression work is more sensitive to the variation of Ar. In the flash system, the energy consumption of condensation in is more sensitive to the variation of Ar; but in the distillation system, the energy consumption of condensation is more sensitive to the variation of SO2, and CO2 purity of separation is more sensitive to the variation of SO2. (author)

  12. Properties of heat-treated calcium phosphate coatings deposited by high-velocity oxy-fuel (HVOF) spray.

    Li, H; Khor, K A; Cheang, P

    2002-05-01

    The influence of crystallization, upon heat treatment, on the properties of high-velocity oxy-fuel (HVOF) sprayed hydroxyapatite (HA) coatings was investigated. The characterization of the HA coating was performed by X-ray diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR). Differential Scanning Calorimeter (DSC) was employed to determine the crystallization temperature of the amorphous phase in an as-sprayed HA coating. The study demonstrated the effect of crystallization on the coating properties by considering the changes in materials chemistry, crystallinity level, and mechanical performance. Results showed that complete crystallization of the amorphous phase occurred at approximately 700 degrees C and the crystallization temperature was dependent on sample heating rate in the DSC test. The changes of ion groups were detected by FTIR, before and after the phase transformation. The crystallization of the coating after annealing at 750 degrees C resulted in a significant increase of the coatings' adhesive strength and shear strength, which attained maximum values 34 +/- 3 and 14.1 -/+ 0.8 MPa, respectively. Young's modulus increased from 21 +/- 1 to 25 +/- 2 GPa. Microhardness measurements confirmed the changes in coating properties. It is also found that the transformation from the amorphous phase has crystalline HA as the only resultant phase detected by XRD. PMID:11962650

  13. Influence of high velocity oxy-fuel parameters on properties of nanostructured TiO2 coatings

    Maryamossadat Bozorgtabar; Mehdi Salehi; Mohammadreza Rahimipour; Mohammadreza Jafarpour

    2010-12-01

    A liquid fuel high velocity oxy-fuel (HVOF) thermal spray process has been used to deposit TiO2 nanostructured coatings utilizing a commercially available nanopowder as the feedstock. The coatings were characterized by means of X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and transmission electron microscope (TEM), respectively. Photocatalytic activity was evaluated as a rate constant of decomposition reaction of methylene blue (MB) determined from the changes of relative concentration of MB with UV irradiation time. The results indicate that the sprayed TiO2 coatings were composed of both TiO2 phases viz. anatase and rutile, with different phase contents and crystallite sizes. A high anatase content of 80% by volume was achieved at 0.00015, fuel-to-oxygen ratio with nanostructure coating by grain size smaller than feedstock powder. Photocatalytic activity evaluation results indicated that all the TiO2 coatings are effective to degradation MB under UV radiation and their activities differ in different spray conditions. It is found that fuel flow rate strongly influenced on phase transformation of anatase to rutile and by optimizing the rate which can promote structural transformation and grain coarsening in coating and improving photocatalytic activity.

  14. Testing of gadolinium oxy-sulphide phosphors for use in CCD-based X-ray detectors for macromolecular crystallography

    Pokric, M

    2002-01-01

    The resolution and detective quantum efficiency of CCD-based detectors used for X-ray diffraction is primarily affected by the layer of phosphor that converts incident X-ray photons into visible photons. The optimum thickness of this phosphor layer is strongly dependent on the fraction of absorbed incident X-ray photons and required spatial resolution. A range of terbium doped gadolinium oxy-sulphide (Gd sub 2 O sub 2 S : Tb) phosphor samples, provided by Applied Scintillation Technologies, have been evaluated for spatial resolution, light output and uniformity. The phosphor samples varied in coating weight (10-25 mg/cm sup 2), grain size (2.5, 4, 10 mu m), and applied coating (no coating, reflectors and absorbers). In addition, a non-uniform layer was introduced to some samples in order to provide an inherent diffusion layer. The experimental results showed that the introduction of a reflector increases the point spread function (PSF) and increases light yield up to 30%, while an absorber reduces the PSF tai...

  15. {alpha}-Tocopherol impact on oxy-radical induced free radical decomposition of DMSO: Spin trapping EPR and theoretical studies

    Jerzykiewicz, Maria, E-mail: Mariaj@wchuwr.pl [Faculty of Chemistry, Wroclaw University, 14 F. Joliot-Curie St., 50-383 Wroclaw (Poland); Cwielag-Piasecka, Irmina; Witwicki, Maciej; Jezierski, Adam [Faculty of Chemistry, Wroclaw University, 14 F. Joliot-Curie St., 50-383 Wroclaw (Poland)

    2011-05-26

    Graphical abstract: {alpha}-Tocopherol inhibits the oxidation of {center_dot}CH{sub 3} to {center_dot}OCH{sub 3}. Display Omitted Highlights: {yields} {alpha}-Tocopherol does not inhibit the oxidation of DMSO to {center_dot}CH{sub 3}. {yields} {alpha}-Tocopherol inhibits the oxidation of {center_dot}CH{sub 3} to {center_dot}OCH{sub 3}. {yields} {alpha}-Tocopherol does not inhibit the oxidation of PBN. {yields} The structures of observed spin adducts were theoretically confirmed. - Abstract: EPR spin trapping and theoretical methods such as density functional theory (DFT) as well as combined DFT and quadratic configuration interaction approach (DFT/QCISD) were used to identify the radicals produced in the reaction of oxy-radicals and dimethyl sulfoxide (DMSO) in the presence and absence of {alpha}-tocopherol. Additionally, the mixtures of {alpha}-tocopherol with linolenic acid and glyceryl trilinoleate as well as bioglycerols (glycerol fractions from biodiesel production) were tested. {alpha}-Tocopherol inhibited oxidation of the main decomposition product of DMSO, {center_dot}CH{sub 3} to {center_dot}OCH{sub 3} but did not prevent the transformation process of N-t-butyl-{alpha}-phenylnitrone (PBN) into 2-methyl-2-nitrosopropane (MNP). Theoretical investigations confirmed the structures of proposed spin adducts and allowed to correlate the EPR parameters observed in the experiment with the spin adducts electronic structure.

  16. Microstructure and hydroabrasive wear behaviour of high velocity oxy-fuel thermally sprayed WC-Co(Cr) coatings

    Sand erosion tests were performed on WC-Co and WC-CoCr coatings deposited by the high velocity oxy-fuel spraying method. Several analytical techniques, including X-ray diffraction, Auger electron spectroscopy and energy-dispersive spectroscopy in a transmission electron microscope were used to characterize the microstructures formed during powder processing and spraying. It was found that a substantial fraction of WC decomposed into W2C or reacted with the cobalt matrix to form ternary carbides such as Co3W3C and other mixed compounds. In both cases the binder phase had a nanocrystalline structure of size 4-8 nm containing tungsten, cobalt, carbon and chromium elements. The addition of chromium inhibits to a large extent the decomposition of WC and avoids the formation of metallic tungsten. In addition, chromium improved the erosion resistance by several times compared with the WC-Co coating. Scanning electron microscopy showed that the CoCr matrix binds carbides better than the cobalt matrix, thereby inhibiting carbide loss at the spray particle boundaries. The hydroabrasive wear behaviour of coatings and the mechanisms for material removal are discussed with respect to the microstructures formed during spraying. (orig.)

  17. Study of intramolecular isotope heterogeneity of organic oxy acids in order to detect sophisticated wines and juice drinks

    Kuzmina Helen

    2014-01-01

    Full Text Available According to International Code of Oenological Practices it is allowed to use acide L(+tartrique for wine acidification, while use of synthetic dihydroxysuccinic acid is forbidden. Today it is impossible to differentiate natural dihydroxysuccinic acid from synthetic one by standard techniques. Even by using very sensitive method of isotope mass spectrometry certain difficulties emerge because total isotope characteristics of carbon of dihydroxysuccinic acid of different nature have the same values. However, isotope characteristics of carbon of intramolecular structural groups of dihydroxysuccinic acid made of different raw materials differ significantly. This allows specifying the nature of dihydroxysuccinic acid that is used for making of wines and juice drinks. In Russia, scientific and research institute of beer brewing and wine-making industry carried out a work for studying isotope characteristics of intramolecular isotope heterogeneity of dihydroxysuccinic acid from different origins in order to identify wines and juice drinks. Isotope characteristics of organic oxy acids from different origins were studied including them obtained by synthetic way and numeric range of value δ13 C,‰ were specified. The obtained results allow performing identification tests of wines and juice drinks to find out the products that contain not specified additives as that allowed for its use in production process.

  18. The mGluR2 Positive Allosteric Modulator BINA Decreases Cocaine Self-Administration and Cue-Induced Cocaine-Seeking and Counteracts Cocaine-Induced Enhancement of Brain Reward Function in Rats

    Jin, Xinchun; Semenova, Svetlana; Yang, Li; Ardecky, Robert; Sheffler, Douglas J.; Dahl, Russell; Conn, P. Jeffrey; Cosford, Nicholas DP; Markou, Athina

    2010-01-01

    Metabotropic glutamate receptor 2/3 (mGluR2/3) agonists were shown previously to nonselectively decrease both cocaine- and food-maintained responding in rats. mGluR2 positive allosteric modulators (PAMs) may represent improved therapeutic compounds because of their modulatory properties and higher selectivity for mGluR2. We analyzed the effects of the selective, brain penetrant, and systemically active mGluR2 PAM potassium 3′-([(2-cyclopentyl-6-7-dimethyl-1-oxo-2,3-dihydro-1H-inden-5-yl)oxy]m...

  19. Crystal structure of (4-meth-oxy-phen-yl)[(4-meth-oxy-phen-yl)phospho-nato]dioxidophosphate(1-) 2-amino-6-benzyl-3-eth-oxy-carbon-yl-4,5,6,7-tetra-hydro-thieno[2,3-c]pyridin-6-ium.

    Mague, Joel T; Mohamed, Shaaban K; Akkurt, Mehmet; Younes, Sabry H H; Ahmed, Essam K; Albayati, Mustafa R

    2015-12-01

    The asymmetric unit of the title mol-ecular salt, C17H21N2O2S(+)·C14H15O7P2 (-), comprises two cations and two anions. Each cation features an intra-molecular N-H⋯O hydrogen bond, which closes an S(6) ring; in each case the hydro-pyridine ring adopts a half-chair conformation. In the anions, the dihedral angles between the aromatic rings are 64.1 (2) and 54.9 (2)°. In each case, the diphosphate groups are close to eclipsed [C-P⋯P-C pseudo-torsion angles = 11.6 (2) and -19.3 (2)°]. One of the meth-oxy groups in each anion is disordered over two orientations in a 0.539 (18):0.461 (18) ratio in one anion and 0.82 (2):0.18 (2) in the other. In the crystal, O-H⋯O and N-H⋯O hydrogen bonds link the components into [100] chains. Numerous C-H⋯O inter-actions cross-link the chains into a three-dimensional network. PMID:26870570

  20. (μ2-2-Meth­oxy­ethanol-κ3 O 1:O 1,O 3)(2-meth­oxy­ethanol-κO 1)tris­(μ2-3,4,5,6-tetra­fluoro-o-phenyl­ene-κ2 C 1:C 2)trimercury(II)

    Castañeda, Raúl; Draguta, Sergiu; Yakovenko, Andrey; Fonari, Marina; Timofeeva, Tatiana

    2014-01-01

    In the title compound, [Hg3(C6F4)3(C3H8O2)2], two O atoms from one 2-meth­oxy­ethanol ligand and one O atom from the second 2-meth­oxy­ethanol ligand coordinate three HgII atoms [Hg—O = 2.765 (7)–2.890 (8) Å] in the trimeric organomercurial Lewis acid (o-C6F4Hg)3. The hy­droxy groups are involved in formation of intra- and inter­molecular O—H⋯O hydrogen bonds; the latter link two mol­ecules into centrosymmetric dimers. An extensive net of weak inter­molecular C—H⋯F inter­actions further conso...

  1. Iron oxi-hydroxides characterization and associated elements (S, Se, As, Mo, V, Zr) in the redox environments favorable for uranium deposits

    This work presents a multi-scale and a multi-technical study for the characterization of iron oxi-hydroxides in three uranium-type deposits and host rock. The choice of sites has focused on a roll front deposit: Zoovch Ovoo in a Cretaceous basin of East Gobi (Mongolia); a tectonic-lithological type: Akola/Ebba in Tim Mersoi basin (Niger) and a Proterozoic unconformity type: Kiggavik in Thelon basin (Canada). A new approach has been implemented to characterize the iron oxi-hydroxides on macroscopic samples: field infrared spectroscopy using the ASD TerraSpec spectrometer. From the original indexes calculated on the spectra, it was possible both to characterize the iron oxi-hydroxides; only hematite and goethite were identified in the different parts of oxidized uranium fronts, and visualize the alteration zonation along the redox front. In addition, the visible part of spectrum was used to quantify the color of samples through the IHS system parameters (Intensity - Hue - Saturation) and the Munsell system. The color setting of the study identified a specific hue for mineralized samples studied: a mixture of yellow and red (2.5 to 10 Yr in Munsell notation). At the crystals scale, the iron-hydroxides were characterized by μ-Raman spectroscopy. The study highlighted a difference in crystallinity of hematite crystals in different fields. From a morphological point of view, the crystals of goethite in the Zoovch Ovoo deposit, is only authigenic iron oxi-hydroxides described in this uranium front, are twinned in the form of six-pointed star, reflecting a low crystallization temperature, compared to Niger and Kiggavik deposits. This crystallization is mainly controlled by the availability of Fe(III) ions in the fluid, released by pyrite dissolution in an oxidizing environment and pH. From a chemical point of view, iron oxi-hydroxides record the fluid passage owing their uranium content. Secondly, the composition in trace elements marks the type of deposit, for example

  2. Comparing the accuracy of ES-BC, EIS-GS, and ES Oxi on body composition, autonomic nervous system activity, and cardiac output to standardized assessments

    Lewis JE

    2011-09-01

    Full Text Available John E Lewis1, Stacey L Tannenbaum1, Jinrun Gao3, Angelica B Melillo1, Evan G Long1, Yaima Alonso2, Janet Konefal1, Judi M Woolger2, Susanna Leonard1, Prabjot K Singh1, Lawrence Chen1, Eduard Tiozzo1 1Department of Psychiatry and Behavioral Sciences, 2Department of Medicine, University of Miami Miller School of Medicine, Miami, FL, 3State Farm Insurance, Bloomington, IL, USA Background and purpose: The Electro Sensor Complex (ESC is software that combines three devices using bioelectrical impedance, galvanic skin response, and spectrophotometry: (1 ES-BC (Electro Sensor-Body Composition; LD Technology, Miami, FL to assess body composition, (2 EIS-GS (Electro Interstitial Scan-Galvanic Skin; LD Technology to predict autonomic nervous system activity, and (3 ES Oxi (Electro Sensor Oxi; LD Technology to assess cardiac output. The objective of this study was to compare each to a standardized assessment: ES-BC to dual-energy X-ray absorptiometry (DXA, EIS-GS to heart rate variability, and ES Oxi to BioZ Dx Diagnostic System (BioZ Dx; SonoSite Inc, Bothell, WA. Patients and methods: The study was conducted in two waves. Fifty subjects were assessed for body composition and autonomic nervous system activity. Fifty-one subjects were assessed for cardiac output. Results: We found adequate relative and absolute agreement between ES-BC and DXA for fat mass (r = 0.97, P < 0.001 with ES-BC overestimating fat mass by 0.1 kg and for body fat percentage (r = 0.92, P < 0.001 with overestimation of fat percentage by 0.4%. For autonomic nervous system activity, we found marginal relative agreement between EIS-GS and heart rate variability by using EIS-GS as the predictor in a linear regression equation (adjusted R2 = 0.56, P = 0.03. For cardiac output, adequate relative and absolute agreement was found between ES Oxi and BioZ Dx at baseline (r = 0.60, P < 0.001, after the first exercise stage (r = 0.79, P < 0.001, and after the second exercise stage (r = 0.86, P

  3. Mesophyll versus epidermal anthocyanins as potential in vivo antioxidants: evidence linking the putative antioxidant role to the proximity of oxy-radical source.

    Kytridis, Velissarios-Phaedon; Manetas, Yiannis

    2006-01-01

    The hypothesis that anthocyanins in red leaves may be potential in vivo antioxidants whose efficiency is linked to their proximity with the oxy-radical source was tested. Advantage was taken of intra-individual and intra-species variations in the anthocyanic trait and green and red leaves on the same individuals or leaves of green and red phenotypes were compared for the extent of PSII damage by reactive oxygen species generated by methyl viologen treatment in the light. Two species possessing anthocyanins in the mesophyll (Cistus creticus and Photinia x fraseri) and two in the epidermis (Rosa sp. and Ricinus communis) were used, while red actinic light (which is not absorbed by anthocyanins) allowed discrimination between an indirect sunscreen and a direct antioxidant function. Red leaves whose anthocyanins were located in the mesophyll were more resistant to methyl viologen treatment than their green counterparts. In one of these species (Cistus creticus), where anthocyanins are induced in some individuals within the natural population after bright cool days in winter, both green and future-red morphs displayed the same sensitivity to methyl viologen before anthocyanin induction. Immediately after reddening, however, resistance to methyl viologen was considerably increased in the red morphs. By contrast, red leaves whose anthocyanins were restricted to epidermal cells were more sensitive to the herbicide. Total leaf phenolic levels in green/red pairs were similar. The results indicate that vacuolar anthocyanins may be an effective in vivo target for oxy-radicals, provided that the oxy-radical source and the anthocyanic detoxifying sink are in close vicinity. PMID:16714309

  4. [Properties of 2,5-diamino-4-oxy-6-ribosylaminopyrimidine-5'- phosphate reductase, a enzyme of the second stage of flavinogenesis in Pichia guilliermondii yeasts].

    Logvinenko, E M; Shavlovskiĭ, G M; Zakal'skiĭ, A E; Kontorovskaia, N Iu

    1989-01-01

    2,5-Diamino-4-oxy-6-ribosylaminopyrimidine-5'-phosphate reductase has been isolated from cells of Pichia guilliermondii and subjected to 20-fold purification by treating extracts with streptomycin sulphate, frationating proteins (NH4)2SO4 at 45-75% of saturation and chromatography on blue sepharose CL-6B. The use of gel filtration through Sephadex G-150 and chromatography on DEAE-cellulose proved to be less effective for the enzyme purification. It has been established that it is 2,5-diamino-4-oxy-6-ribosylaminopyrimidine-5-phosphate but not its dephosphorylated form that is the substrate of the given reductase; Km is equal to 7.10(-5) M. The reaction proceeds in the presence of NADPH or NADH. The enzyme affinity to NADPH (Km = 4.7.10(-5) M) is approximately one order higher than that to NADPH (Km = 5.5.10(-4) M). The enzyme manifests the optimum of action at pH 7.2 and the temperature of 37 degrees C; the molecular weight is 140 kD. EDTA as well as flavins in the concentration of 1.10(-3) M exert no effect on the reductase activity. The enzyme is labile at 4 degrees C and is inactivated in the frozen state at -15 degrees C. The 2.5-diamino-4-oxy-6-ribosylaminopyrimidine-5'-phosphate reductase has been also revealed in Torulopsis candida, Debaryomyces klöckeri, Schwanniomyces occidentalis, Eremothecium ashbyii (flavinogenic species) and Candida utilis. Aspergillus nidulans, Neurospora crassa (nonflavinogenic species). The synthesis of this enzyme contrary to other enzymes of the riboflavin biosynthesis is not regulated in flavinogenic yeast by iron ions. PMID:2511652

  5. High-dose OxyContin to treat pain associated with bone metastasis in patients with small-cell lung cancer: a case study report

    Zhou T

    2016-01-01

    Full Text Available Tao Zhou,1,* Xia Zhang,2,* Yan Dong,1 Feifei Zhuang,1 Fengquan Jiang,3 Jinming Yu,4 Bin Zhang1,4 1Department of Oncology, The First Affiliated Hospital of Dalian Medical University, Dalian, 2Department of Oncology, Shandong Cancer Hospital and Institute, Shandong University, Jinan, 3Laboratory of Medicine, The First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning, 4Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Shandong University, Jinan, Shandong, People’s Republic of China *These authors contributed equally to this work Abstract: Pain management is an important topic that has received extensive attention from clinical practitioners. Nearly all patients with malignant tumors suffer pain at the advanced stage of their disease. Oxycodone is a first-line choice for treating moderate-to-severe cancer-related pain, and OxyContin, a controlled-release oxycodone hydrochloride tablet, is internationally recognized as a safe and effective opioid analgesic. OxyContin has the characteristics of both immediate release and sustained release, with a time to onset and peak similar to those of immediate-release morphine. It acts on both µ and κ receptors and has been shown to be effective in treating different types of pain, especially neuropathic pain, theoretically without a dose cap. However, the dose is limited in clinical applications due to various factors that are likely to affect its analgesic effect and reduce patient quality of life. Cooperation with a patient’s family members is required during the treatment of cancer pain. Chronic cancer pain has a long disease course, which could easily cause complex psychological symptoms due to their important role in the pain experience. Pain is controllable, and patients have a right to not experience pain. An optimal living state can be achieved through collaboration between physicians and patients. Rational personalized treatment of cancer pain can improve

  6. Crystal structure of 2-(4-meth-oxy-phen-yl)-6-nitro-imidazo[1,2-a]pyridine-3-carbaldehyde.

    Koudad, Mohamed; Elaatiaoui, Abdelmalik; Benchat, Noureddine; Saadi, Mohamed; El Ammari, Lahcen

    2015-12-01

    In the title compound, C15H11N3O4, the imidazo[1,2-a] pyridine ring system is almost planar [r.m.s. deviation = 0.028 (2) Å]. Its mean plane makes dihedral angles of 33.92 (7) and 34.56 (6)° with the meth-oxy-phenyl ring and the nitro group, respectively. The cohesion of the crystal structure is ensured by C-H⋯N and C-H⋯O hydrogen bonds, forming layers almost parallel to the ac plane. PMID:26870561

  7. Oxy-fuel combustion kinetics and morphology of coal chars obtained in N2 and CO2 atmospheres in an entrained flow reactor

    Gil Matellanes, María Victoria; Riaza Benito, Juan; Álvarez González, Lucía; Pevida García, Covadonga; Pis Martínez, José Juan; Rubiera González, Fernando

    2012-01-01

    The thermal reactivity and kinetics of four coal chars (HVN, UM, SAB and BA) in an oxy-fuel combustion atmosphere (30%O2–70%CO2) were studied using a thermobalance. The coal chars were obtained by devolatilization in an entrained flow reactor (EFR) at 1000 °C for 2.5 s under 100% N2 and CO2 atmospheres. The reactivity tests were carried out by isothermal thermogravimetric analysis at different temperatures in a kinetically controlled regime. Three nth-order representative gas–solid models – t...

  8. Single particle ignition and combustion of anthracite, semi-anthracite and bituminous coals in air and simulated oxy-fuel conditions

    Riaza Benito, Juan; Khatami, Reza; Levendis, Yiannis A.; Álvarez González, Lucía; Gil Matellanes, María Victoria; Pevida García, Covadonga; Rubiera González, Fernando; Pis Martínez, José Juan

    2014-01-01

    A fundamental investigation has been conducted on the combustion behavior of single particles (75–150 μm) of four coals of different ranks: anthracite, semi-anthracite, medium-volatile bituminous and high-volatile bituminous. A laboratory-scale transparent laminar-flow drop-tube furnace, electrically-heated to 1400 K, was used to burn the coals. The experiments were performed in different combustion atmospheres: air (21%O2/79%N2) and four simulated dry oxy-fuel conditions: 21%O2/79%CO2, 30%O2...

  9. A comprehensive evaluation of the influence of air combustion and oxy-fuel combustion flue gas constituents on Hg0 re-emission in WFGD systems

    Ochoa González, Raquel; Díaz Somoano, Mercedes; Martínez Tarazona, María Rosa

    2014-01-01

    This paper evaluates the influence of the main constituents of flue gases from coal combustion (CO2, O2, N2 and water vapor), in air and oxy-fuel combustion conditions on the re-emission of Hg0 in wet scrubbers. It was observed that the concentration of water vapor does not affect the re-emission of mercury, whereas O2 and CO2 have a notable influence. High concentrations of O2 in the flue gas prevent the re-emission of Hg0 due to the reaction of oxygen with the metals present in low oxidatio...

  10. Kinetic models for the oxy-fuel combustion of coal and coal/biomass blend chars obtained in N2 and CO2 atmospheres

    Gil Matellanes, María Victoria; Riaza Benito, Juan; Álvarez González, Lucía; Pevida García, Covadonga; Pis Martínez, José Juan; Rubiera González, Fernando

    2012-01-01

    The thermal reactivity and kinetics of five coal chars, a biomass char, and two coal/biomass char blends in an oxy-fuel combustion atmosphere (30%O2–70%CO2) were studied using the non-isothermal thermogravimetric method at three heating rates. Fuel chars were obtained by devolatilization in an entrained flow reactor at 1273 K under N2 and CO2 atmospheres. Three nth-order representative gas–solid models – the volumetric model (VM), the grain model (GM) and the random pore model (RPM) – were em...

  11. ENTHALPY RELAXATIONS AND CONCENTRATION FLUCTUATIONS IN BLENDS OF POLYSTYRENE AND POLY(OXY-2,6-DIMETHYL-1,4-PHENYLENE)

    OUDHUIS, AACM; TENBRINKE, G

    1992-01-01

    A series of enthalpy relaxation measurements were carried out for the pure polymers polystyrene (PS) and poly(oxy-2,6-dimethyl-1,4-phenylene) (PPE) and for homogeneous blends thereof. The data were analyzed using Moynihan's four-parameter approach.4 For the pure components the best fit parameter values for the simple cooling/heating experiments differ somewhat from those for the annealing experiments at least partly due to thermal lag. The amount of enthalpy relaxation during annealing of the...

  12. Characterization of the oxy-fired regenerator at a 10 kWth dual fluidized bed calcium looping facility

    Calcium looping is a CO2 capture technology, developed in the last years with great potential to contribute to the reduction of greenhouse gases emissions. It consists of a carbonator where CO2 contained in power plant flue gas, is absorbed by CaO producing CaCO3 and a regenerator where the CaCO3 is calcined to CaO releasing a highly concentrated CO2 stream. A key aspect of the process is the oxy-combustion of the fuel in the regenerator to provide the heat for the endothermic calcination reaction. This implies high CO2 concentration in the off-gas and requires a flue gas recycle. Aim of this work is the characterization of the regenerator operation under this environment and thus experiments were performed at the 10 kWth IFK Dual Fluidized Bed facility. Regenerator efficiency and sorbent performance in terms of chemical activity and mechanical stability are the two basic parameters investigated, while the active space time is used for interpretation of the results. It is found that high calcination conversions can be achieved with temperatures less than 920 °C. Sorbent achieves a residual CO2 carrying capacity similar to the one referred to the literature. The sorbent proved to be mechanically strong thus optimistic percentage of material loss was recorded to be 0.8 wt.%/h or 0.024 mol Ca/mol CO2. - Highlights: • CaL experiments at a 10 kWth DFB system under high CO2 concentration. • Performance of the regenerator in terms of calcination efficiency is studied. • Regenerator efficiency is correlated to reactor geometry and lime properties. • Lime chemical decay over time is recorded. • Material losses are measured in realistic CFB conditions

  13. Computational fluid dynamic modeling of gas flow characteristics in a high-velocity oxy-fuel thermal spray system

    Gu, S.; Eastwick, C. N.; Simmons, K. A.; McCartney, D. G.

    2001-09-01

    A computational fluid dynamics (CFD) model is developed to predict gas dynamic behavior in a high-velocity oxy-fuel (HVOF) thermal spray gun in which premixed oxygen and propylene are burnt in a 12 mm combustion chamber linked to a parallel-sided nozzle. The CFD analysis is applied to investigate axisymmetric, steady-state, turbulent, compressible, and chemically combusting flow both within the gun and in a free jet region between the gun and the substrate to be coated. The combustion of oxygen and propylene is modeled using a single-step, finite-rate chemistry model that also allows for dissociation of the reaction products. Results are presented to show the effect of (1) fuel-to-oxygen gas ratio and (2) total gas flow rate on the gas dynamic behavior. Along the centerline, the maximum temperature reached is insensitive to the gas ratio but depends on the total flow. However, the value attained (˜2500 K) is significantly lower than the maximum temperature (˜3200 K) of the annular flame in the combustion chamber. By contrast, the centerline gas velocity depends on both total flow and gas ratio, the highest axial gas velocity being attained with the higher flow and most fuel-rich mixture. The gas Mach number increases through the gun and reaches a maximum value of approximately 1.6 around 5 mm downstream from the nozzle exit. The numerical calculations also show that the residual oxygen level is principally dependent on the fuel-to-oxygen ratio and decreases by approximately fivefold as the ratio is varied from 90 to 69% of the stoichiometric requirement. The CFD model is also used to investigate the effect of changes in combustion chamber size and geometry on gas dynamics, and the results are compared with the nominal 12 mm chamber baseline calculations.

  14. CFD (computational fluid dynamics) analysis of a novel reactor design using ion transport membranes for oxy-fuel combustion

    Conventional two-channel ITM (ion transport membrane) reactors applied to oxy-combustion, face the potential drawback of high thermal gradients and high local temperatures, which can result in membrane damage. In such reactors, air flows on the feed side and fuel are introduced on the permeate side, where it reacts with the permeated oxygen. In this work, we propose to use a three-channel configuration in which a porous plate is used to separate the permeate stream from the fuel stream, allowing the fuel to diffuse gradually into the permeate side. The gradual combustion of the fuel results in a slow temperature rise and a more spatially uniform temperature distribution along the membrane. We model this three-channel reactor using computational fluid dynamics and compare its performance to a conventional two-channel reactor. It is shown that, indeed, in case of a two-channel reactor, a high temperature zone is concentrated near the inlet, whereas the three-channel reactor produces a milder temperature gradient along the reactor length. The more-uniform heat flux associated with the latter results in a moderate temperature distribution and reduction in the wall shear stress along the channels and the associated pressure drop. The more uniform temperature distribution should be less damaging to the membrane. The reaction zone associated with the gradual fuel diffusion into the sweep side improves the membrane performance by maintaining a more uniform oxygen flux. - Highlights: • A novel concept of 3-channel reactor using ITM (ion transport membrane) is presented. • Comparison of present 3-channel reactor with the conventional 2-channel reactor. • A more spatially uniform temperature is obtained using the 3-channel reactor. • 3-channel reactor produces a milder temperature gradient along the reactor length. • The reaction zone in 3-channel reactor improves the membrane performance

  15. Numerical study on NO formation in a pulverized coal-fired furnace using oxy-fuel combustion

    Zhang, Aiyue; Chen, Yuan; Sheng, Changdong [Southeast Univ., Nanjing (China). School of Energy and Environment

    2013-07-01

    Computational fluid dynamics (CFD) approach was employed to numerically investigate NO formation in a 600 MW wall-fired pulverized coal-fired furnace retrofitted for oxy-coal combustion, aimed at the impacts of flue gas recycle ratio, O{sub 2} staging and recycled NO with the recycled flue gas (RFG) on NO formation and emission. An in-house CFD research code for conventional air combustion was developed and extended to simulate O{sub 2}/RFG combustion with specific considerations of the change of gas properties and its impact on coal particle combustion processes. The extended De Soete mechanisms including NO reburning mechanism were applied to describe transformations of fuel nitrogen. It was shown that CFD simulation represented the significant reduction of NO formation during O{sub 2}/RFG combustion compared to that during air combustion. The in-burner and particularly the in-furnace O{sub 2} staging were confirmed still to play very important roles in NO formation control. Changing the recycle ratio had significant impact on the combustion performance and consequently on NO formation and emission. With the combustion performance ensured, decreasing the flue gas recycle ratio or increasing the inlet O{sub 2} concentration of combustion gas led to reduction of NO formation and emission. Although NO formation and emission was found to increase with increasing the inlet NO concentration of combustion gas, CFD simulation indicated that {proportional_to}74% of the inlet NO was reduced in the furnace, consistent with the experimental data reported in the literature. This demonstrated the significant contribution of reburning mechanism to the reduction of the recycled NO in the furnace.

  16. Elucidating the mechanism of Cr(VI) formation upon the interaction with metal oxides during coal oxy-fuel combustion.

    Chen, Juan; Jiao, Facun; Zhang, Lian; Yao, Hong; Ninomiya, Yoshihiko

    2013-10-15

    The thermodynamics underpinning the interaction of Cr-bearing species with basic metal oxides, i.e. K2O, Fe2O3, MgO and CaO, during the air and oxy-fuel combustion of coal have been examined. The synchrotron-based X-ray adsorption near-edge spectroscopy (XANES) was used for Cr speciation. For the oxides tested, Cr(VI) formation is dominated by the reduction potential of the metals. The oxides of Ca(2+) with high reduction potential favored the oxidation of Cr(III), same for K(+). The other two basic metals, Fe2O3 and MgO with lower reduction potentials reacted with Cr(III) to form the corresponding chromites at the temperatures above 600°C. Coal combustion experiments in drop-tube furnace have confirmed the rapid capture of Cr vapors, either trivalent or hexavalent, by CaO into solid ash. The existence of HCl in flue gas favored the vaporization of Cr as CrO2Cl2, which was in turn captured by CaO into chromate. Both Fe2O3 and MgO exhibited less capability on scavenging the Cr(VI) vapor. Particularly, MgO alone exhibited a low capability for capturing the vaporized Cr(III) vapors. However, its co-existence with CaO in the furnace inhibited the Cr(VI) formation. This is beneficial for minimizing the toxicity of Cr in the coal combustion-derived fly ash. PMID:23969010

  17. Development of wear resistant nanostructured duplex coatings by high velocity oxy-fuel process for use in oil sands industry.

    Saha, Gobinda C; Khan, Tahir I; Glenesk, Larry B

    2009-07-01

    Oil sands deposits in Northern Alberta, Canada represent a wealth of resources attracting huge capital investment and significant research focus in recent years. As of 2005, crude oil production from the current oil sands operators accounted for 50% of Canada's domestic production. Alberta's oil sands deposits contain approximately 1.7 trillion barrels of bitumen, of which over 175 billion are recoverable with current technology, and 315 billion barrels are ultimately recoverable with technological advances. A major problem of operating machinery and equipment in the oil sands is the unpredictable failure from operating in this highly aggressive environment. One of the significant causes of that problem is premature material wear. An approach to minimize this wear is the use of protective coatings and, in particular, a cermet thin coating. A high level of coating homogeneity is critical for components such as bucketwheels, draglines, conveyors, shovels, heavyhauler trucks etc. that are subjected to severe degradation through abrasive wear. The identification, development and application of optimum wear solutions for these components pose an ongoing challenge. Nanostructured cermet coatings have shown the best results of achieving the degree of homogeneity required for these applications. In this study, WC-17Co cermet powder with nanocrystalline WC core encapsulated with 'duplex' Co layer was used to obtain a nanostructured coating. To apply this coating, high velocity oxy-fuel (HVOF) thermal spraying technique was used, as it is known for producing wear-resistant coatings superior to those obtained from plasma-based techniques. Mechanical, sliding wear and microstructural behavior of the coating was compared with those of the microstructured coating obtained from spraying WC-10Co-4Cr cermet powder by HVOF technique. Results from the nanostructured coating, among others, showed an average of 25% increase in microhardness, 30% increase in sliding wear resistance and

  18. Elucidating the mechanism of Cr(VI) formation upon the interaction with metal oxides during coal oxy-fuel combustion

    Highlights: • The presence of Ca2+/K+ oxide in coal favored the enrichment of toxic Cr(VI) in coal combustion derived fly ash. • Fe2O3 and MgO in coal are critical on the inhibition of Cr(VI) formation during coal combustion. • Cr(VI) formation extent is correlated positively with the standard reduction potential of metal oxide in coal. -- Abstract: The thermodynamics underpinning the interaction of Cr-bearing species with basic metal oxides, i.e. K2O, Fe2O3, MgO and CaO, during the air and oxy-fuel combustion of coal have been examined. The synchrotron-based X-ray adsorption near-edge spectroscopy (XANES) was used for Cr speciation. For the oxides tested, Cr(VI) formation is dominated by the reduction potential of the metals. The oxides of Ca2+ with high reduction potential favored the oxidation of Cr(III), same for K+. The other two basic metals, Fe2O3 and MgO with lower reduction potentials reacted with Cr(III) to form the corresponding chromites at the temperatures above 600 °C. Coal combustion experiments in drop-tube furnace have confirmed the rapid capture of Cr vapors, either trivalent or hexavalent, by CaO into solid ash. The existence of HCl in flue gas favored the vaporization of Cr as CrO2Cl2, which was in turn captured by CaO into chromate. Both Fe2O3 and MgO exhibited less capability on scavenging the Cr(VI) vapor. Particularly, MgO alone exhibited a low capability for capturing the vaporized Cr(III) vapors. However, its co-existence with CaO in the furnace inhibited the Cr(VI) formation. This is beneficial for minimizing the toxicity of Cr in the coal combustion-derived fly ash

  19. Near-infrared oxymeter prototype for noninvasive analysis of rat brain oxygenation

    Crespi, Francesco; Donini, Maurizio; Bandera, Andrea; Heidbreder, Christian; Salvatori, Giorgia; Rovati, Luigi

    2004-09-01

    The feasibility of non-invasive analysis of brain activities was studied in the attempt to overcome the major limitation of actual in vivo methodologies i.e. invasiveness. Optic fibre probes were used as optical head of a novel, highly sensitive near infrared continuous wave spectroscopy (CW-NIR) instrument. This prototype was designed for non-invasive analysis of the two main forms of haemoglobin: oxy-haemoglobin (HbO2) and deoxy-haemoglobin (Hb), chromophores present in biological tissues. It was tested in peripheral tissue (human gastrocnemius muscle) and then reset to perform measurement on rat brain. In animal studies, the optical head was firmly placed using stereotaxic apparatus upon the sagittal line of anaesthetised adult rat's head, without any surgery. Then pharmacological treatments with saline (300μl s.c.) amphetamine (2mg/kg) or nicotine (0.4mg/kg) were performed. Within 10-20 min amphetamine substantially increased HbO2 and reduced Hb control levels. Nicotine produced a rapid initial increase followed by a decrease of HbO2. In contrast to amphetamine, nicotine treatment also reduced Hb and blood volume. These results support the capacity of our CW-NIR prototype to measure non-invasively HbO2 and Hb levels in the rat brain, markers of the degree of tissue oxygenation, index of blood level then of the state of brain metabolism.

  20. Genome-wide Reconstruction of OxyR and SoxRS Transcriptional Regulatory Networks under Oxidative Stress in Escherichia coli K-12 MG1655

    Sang Woo Seo

    2015-08-01

    Full Text Available Three transcription factors (TFs, OxyR, SoxR, and SoxS, play a critical role in transcriptional regulation of the defense system for oxidative stress in bacteria. However, their full genome-wide regulatory potential is unknown. Here, we perform a genome-scale reconstruction of the OxyR, SoxR, and SoxS regulons in Escherichia coli K-12 MG1655. Integrative data analysis reveals that a total of 68 genes in 51 transcription units (TUs belong to these regulons. Among them, 48 genes showed more than 2-fold changes in expression level under single-TF-knockout conditions. This reconstruction expands the genome-wide roles of these factors to include direct activation of genes related to amino acid biosynthesis (methionine and aromatic amino acids, cell wall synthesis (lipid A biosynthesis and peptidoglycan growth, and divalent metal ion transport (Mn2+, Zn2+, and Mg2+. Investigating the co-regulation of these genes with other stress-response TFs reveals that they are independently regulated by stress-specific TFs.

  1. Near-Zero Emissions Oxy-Combustion Flue Gas Purification Task 2: SOx/Nox/Hg Removal for High Sulfur Coal

    Nick Degenstein; Minish Shah; Doughlas Louie

    2012-05-01

    The goal of this project is to develop a near-zero emissions flue gas purification technology for existing PC (pulverized coal) power plants that are retrofitted with oxy-combustion technology. The objective of Task 2 of this project was to evaluate an alternative method of SOx, NOx and Hg removal from flue gas produced by burning high sulfur coal in oxy-combustion power plants. The goal of the program was not only to investigate a new method of flue gas purification but also to produce useful acid byproduct streams as an alternative to using a traditional FGD and SCR for flue gas processing. During the project two main constraints were identified that limit the ability of the process to achieve project goals. 1) Due to boiler island corrosion issues >60% of the sulfur must be removed in the boiler island with the use of an FGD. 2) A suitable method could not be found to remove NOx from the concentrated sulfuric acid product, which limits sale-ability of the acid, as well as the NOx removal efficiency of the process. Given the complexity and safety issues inherent in the cycle it is concluded that the acid product would not be directly saleable and, in this case, other flue gas purification schemes are better suited for SOx/NOx/Hg control when burning high sulfur coal, e.g. this project's Task 3 process or a traditional FGD and SCR.

  2. Effects of low concentration biodiesel blends application on modern passenger cars. Part 3: Impact on PAH, nitro-PAH, and oxy-PAH emissions

    This study explores the impact of five different types of methyl esters on polycyclic aromatic hydrocarbon (PAH), nitrated-PAH and oxygenated PAH emissions. The measurements were conducted on a chassis dynamometer, according to the European regulation. Each of the five different biodiesels was blended with EN590 diesel at a proportion of 10-90% v/v (10% biodiesel concentration). The vehicle was a Euro 3 compliant common-rail diesel passenger car. Emission measurements were performed over the NEDC and compared with those of the real traffic-based Artemis driving cycles. The experimental results showed that the addition of biodiesel led to some important increases in low molecular-weight PAHs (phenanthrene and anthracene) and to both increases and reductions in large PAHs which are characterised by their carcinogenic and mutagenic properties. Nitro-PAHs were found to reduce with biodiesel whereas oxy-PAH emissions presented important increases with the biodiesel blends. The impact of biodiesel source material was particularly clear on the formation of PAH compounds. It was found that most PAH emissions decreased as the average load and speed of the driving cycle increased. Cold-start conditions negatively influenced the formation of most PAH compounds. A similar trend was observed with particulate alkane emissions. - This investigation is a contribution to the understanding the impact of different biodiesels on the formation of PAHs, nitro-PAHs and oxy-PAHs over different driving conditions.

  3. Chemical Force Spectroscopy Evidence Supporting the Layer-by-Layer Model of Organic Matter Binding to Iron (oxy)Hydroxide Mineral Surfaces

    Chassé, Alexander W.

    2015-08-18

    © 2015 American Chemical Society. The adsorption of dissolved organic matter (DOM) to metal (oxy)hydroxide mineral surfaces is a critical step for C sequestration in soils. Although equilibrium studies have described some of the factors controlling this process, the molecular-scale description of the adsorption process has been more limited. Chemical force spectroscopy revealed differing adhesion strengths of DOM extracted from three soils and a reference peat soil material to an iron (oxy)hydroxide mineral surface. The DOM was characterized using ultrahigh-resolution negative ion mode electrospray ionization Fourier Transform ion cyclotron resonance mass spectrometry. The results indicate that carboxyl-rich aromatic and N-containing aliphatic molecules of DOM are correlated with high adhesion forces. Increasing molecular mass was shown to decrease the adhesion force between the mineral surface and the DOM. Kendrick mass defect analysis suggests that mechanisms involving two carboxyl groups result in the most stable bond to the mineral surface. We conceptualize these results using a layer-by-layer "onion" model of organic matter stabilization on soil mineral surfaces.

  4. Two-week cast immobilization induced chronic widespread hyperalgesia in rats.

    Ohmichi, Y; Sato, J; Ohmichi, M; Sakurai, H; Yoshimoto, T; Morimoto, A; Hashimoto, T; Eguchi, K; Nishihara, M; Arai, Y-C P; Ohishi, H; Asamoto, K; Ushida, T; Nakano, T; Kumazawa, T

    2012-03-01

    It has been postulated that physical immobilization is an essential factor in developing chronic pain after trauma or surgery in an extremity. However, the mechanisms of sustained immobilization-induced chronic pain remain poorly understood. The present study, therefore, aimed to develop a rat model for chronic post-cast pain (CPCP) and to clarify the mechanism(s) underlying CPCP. To investigate the effects of cast immobilization on pain behaviours in rats, one hindlimb was immobilized for 2 weeks with a cast and remobilization was conducted for 10 weeks. Cast immobilization induced muscle atrophy and inflammatory changes in the immobilized hindlimb that began 2 h after cast removal and continued for 1 week. Spontaneous pain-related behaviours (licking and reduction in weight bearing) in the immobilized hindlimb were observed for 2 weeks, and widespread mechanical hyperalgesia in bilateral calves, hindpaws and tail all continued for 5-10 weeks after cast removal. A sciatic nerve block with lidocaine 24 h after cast removal transitorily abolished bilateral mechanical hyperalgesia in CPCP rats, suggesting that sensory inputs originating in the immobilized hindlimb contribute to the mechanism of both ipsilateral and contralateral hyperalgesia. Intraperitoneal injection of the free radical scavengers 4-hydroxy-2,2,6,6-tetramethylpiperydine-1-oxy1 or N-acetylcysteine 24 h after cast removal clearly inhibited mechanical hyperalgesia in bilateral calves and hindpaws in CPCP rats. These results suggest that cast immobilization induces ischaemia/reperfusion injury in the hindlimb and consequent production of oxygen free radicals, which may be involved in the mechanism of widespread hyperalgesia in CPCP rats. PMID:22337282

  5. Rat Genome Database (RGD)

    U.S. Department of Health & Human Services — The Rat Genome Database (RGD) is a collaborative effort between leading research institutions involved in rat genetic and genomic research to collect, consolidate,...

  6. OxyR and SoxR modulate the inducible oxidative stress response and are implicated during different stages of infection for the bacterial phytopathogen Pantoea stewartii subsp. stewartii.

    Burbank, Lindsey; Roper, M Caroline

    2014-05-01

    Reactive oxygen species (ROS) from a variety of sources are often encountered by invading plant pathogens during the infection process. Pantoea stewartii subsp. stewartii, the etiological agent of Stewart's wilt, is a serious bacterial pathogen of sweet corn that colonizes both the apoplast and xylem tissues in which ROS are produced. The P. stewartii genome predicts the presence of two redox-sensing transcriptional regulators, OxyR and SoxR, which both activate gene expression in response to oxidative stress. ROS exposure in the form of hydrogen peroxide and the superoxide-generating compound paraquat initiates an induced stress response through OxyR and SoxR that includes activation of the ROS-detoxifying enzymes alkyl hydroperoxide reductase and superoxide dismutase. P. stewartii ΔsoxR was more sensitive to paraquat and was compromised in the ability to form water-soaked lesions, while ΔoxyR was more sensitive to hydrogen peroxide treatment and was deficient in exopolysaccharide production and the elicitation of wilting symptoms. This demonstrates that both SoxR and OxyR play an important role in virulence in the different niches that P. stewartii colonize during the infection process. PMID:24450773

  7. Oxy-schorl, Na(Fe2+2Al)Al6Si6O18(BO3)3(OH)3O, a new mineral from Zlatá Idka, Slovak Republic and Přibyslavice, Czech Republic

    Bačík, P.; Cempírek, J.; Uher, P.; Novák, M.; Ozdín, D.; Filip, J.; Škoda, R.; Breiter, Karel; Klementová, Mariana; Ďuďa, R.; Groat, L. A.

    2013-01-01

    Roč. 98, 2/3 (2013), s. 485-492. ISSN 0003-004X Institutional support: RVO:67985831 ; RVO:68378271 Keywords : Oxy-schorl * tourmaline-supergroup minerals * new mineral * electron microanalysis * crystal-structure refinement * Přibyslavice * Zlatá Idka Subject RIV: DB - Geology ; Mineralogy Impact factor: 2.059, year: 2013

  8. Process simulation of oxy-fuel combustion for a 300 MW pulverized coal-fired power plant using Aspen Plus

    Graphical abstract: This paper studied the combustion processes of pulverized coal in a 300 MW power plant using Aspen Plus software. The amount of each component in flue gas in coal-fired processes with air or O2/CO2 as oxidizer was obtained. The differences between the two processes were identified, and the parameter influences of temperature, excess oxygen ratio and molar fraction of O2/CO2 on the proportions of different components in flue gas were examined by sensitivity analysis. - Highlights: • Combustion processes were studied with Aspen Plus for a 300 MW pulverized coal power plant. • The amount of each flue gas component in coal-fired processes with air or O2/CO2 as oxidizer was obtained. • Differences between the two process models were identified. • The influences of operation parameters on the flue gas components were examined. - Abstract: This work focuses on the amounts and components of flue gas for oxy-fuel combustion in a coal-fired power plant (CFPP). The combustion process of pulverized coal in a 300 MW power plant is studied using Aspen Plus software. The amount of each component in flue gas in coal-fired processes with air or O2/CO2 as oxidizer is obtained. The differences between the two processes are identified, and the influences of temperature, excess oxygen ratio and molar fraction of O2/CO2 on the proportions of different components in flue gas are examined by sensitivity analysis. The process simulation results show that replacing atmospheric air by a 21%O2/79%CO2 mixture leads the decrease of the flame temperature from 1789 °C to 1395 °C. The equilibrium amount of NOx declines obviously but the SOx are still at the same level. The mass fraction of CO2 in flue gas increased from 21.3% to 81.5%. The amount of NOx is affected sensitively by the change of temperature and the excess oxygen ratio, but the change of O2/CO2 molar fraction has a little influence to the generation of NOx. With the increasing of O2 concentration, the

  9. Elucidating the mechanism of Cr(VI) formation upon the interaction with metal oxides during coal oxy-fuel combustion

    Chen, Juan [Department of Chemical Engineering, Monash University, Clayton, GPO Box 36, Victoria 3800 (Australia); State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan 430074 (China); Jiao, Facun [Department of Applied Chemistry, Chubu University, 1200 Matsumoto-Cho, Kasugai, Aichi 487-8501 (Japan); Zhang, Lian, E-mail: lian.zhang@monash.edu [Department of Chemical Engineering, Monash University, Clayton, GPO Box 36, Victoria 3800 (Australia); Yao, Hong [State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan 430074 (China); Ninomiya, Yoshihiko [Department of Applied Chemistry, Chubu University, 1200 Matsumoto-Cho, Kasugai, Aichi 487-8501 (Japan)

    2013-10-15

    Highlights: • The presence of Ca{sup 2+}/K{sup +} oxide in coal favored the enrichment of toxic Cr(VI) in coal combustion derived fly ash. • Fe{sub 2}O{sub 3} and MgO in coal are critical on the inhibition of Cr(VI) formation during coal combustion. • Cr(VI) formation extent is correlated positively with the standard reduction potential of metal oxide in coal. -- Abstract: The thermodynamics underpinning the interaction of Cr-bearing species with basic metal oxides, i.e. K{sub 2}O, Fe{sub 2}O{sub 3}, MgO and CaO, during the air and oxy-fuel combustion of coal have been examined. The synchrotron-based X-ray adsorption near-edge spectroscopy (XANES) was used for Cr speciation. For the oxides tested, Cr(VI) formation is dominated by the reduction potential of the metals. The oxides of Ca{sup 2+} with high reduction potential favored the oxidation of Cr(III), same for K{sup +}. The other two basic metals, Fe{sub 2}O{sub 3} and MgO with lower reduction potentials reacted with Cr(III) to form the corresponding chromites at the temperatures above 600 °C. Coal combustion experiments in drop-tube furnace have confirmed the rapid capture of Cr vapors, either trivalent or hexavalent, by CaO into solid ash. The existence of HCl in flue gas favored the vaporization of Cr as CrO{sub 2}Cl{sub 2}, which was in turn captured by CaO into chromate. Both Fe{sub 2}O{sub 3} and MgO exhibited less capability on scavenging the Cr(VI) vapor. Particularly, MgO alone exhibited a low capability for capturing the vaporized Cr(III) vapors. However, its co-existence with CaO in the furnace inhibited the Cr(VI) formation. This is beneficial for minimizing the toxicity of Cr in the coal combustion-derived fly ash.

  10. Relation between the neuronal and hemodynamic response in the lesioned rat spinal cord following peripheral nerve stimulation

    Dubeau, S.; Beaumont, E.; Lesage, F.

    2009-02-01

    In this study, we explore the hemodynamic response in the lesioned rat spinal cord following peripheral nerve stimulation. Oxy and deoxy hemoglobin were measured (using a four color LED multispectral intrinsic optical imaging system) simultaneously with blood flow (laser speckle measurement). Both optical and electrophysiological data are compared spatially and against stimulation strength. When compared with non-lesioned animals, the hemodynamic response is seen to display significant differences exhibiting increased initial dip and decreased blood drain following stimulation. The origin of the difference is observed to be due to the vascular nature of the injury. The distinct hemodynamic responses may have a strong impact on General Linear Model based fMRI studies of spinal cord lesions due to the difficulty in separating vascular effects from neuronal plasticity following injury.

  11. Recovery Act: Oxy-Combustion Technology Development for Industrial-Scale Boiler Applications. Task 4 - Testing in Alstom's 15 MWth Boiler Simulation Facility

    Levasseur, Armand

    2014-04-30

    Alstom Power Inc. (Alstom), under U.S. DOE/NETL Cooperative Agreement No. DE-NT0005290, is conducting a development program to generate detailed technical information needed for application of oxy-combustion technology. The program is designed to provide the necessary information and understanding for the next step of large-scale commercial demonstration of oxy combustion in tangentially fired boilers and to accelerate the commercialization of this technology. The main project objectives include: Design and develop an innovative oxyfuel system for existing tangentially-fired boiler units that minimizes overall capital investment and operating costs; Evaluate performance of oxyfuel tangentially fired boiler systems in pilot scale tests at Alstom’s 15 MWth tangentially fired Boiler Simulation Facility (BSF); Address technical gaps for the design of oxyfuel commercial utility boilers by focused testing and improvement of engineering and simulation tools; Develop the design, performance and costs for a demonstration scale oxyfuel boiler and auxiliary systems; Develop the design and costs for both industrial and utility commercial scale reference oxyfuel boilers and auxiliary systems that are optimized for overall plant performance and cost; and, Define key design considerations and develop general guidelines for application of results to utility and different industrial applications. The project was initiated in October 2008 and the scope extended in 2010 under an ARRA award. The project is scheduled for completion by April 30, 2014. Central to the project is 15 MWth testing in the BSF, which provided in-depth understanding of oxy-combustion under boiler conditions, detailed data for improvement of design tools, and key information for application to commercial scale oxy-fired boiler design. Eight comprehensive 15 MWth oxy-fired test campaigns were performed with different coals, providing detailed data on combustion, emissions, and thermal behavior over a matrix of

  12. The guidelines for the design and layout of oxy-fuel combustor based on the experiments of pulverized coal combusted in Ar, N{sub 2} and CO{sub 2} respectively

    Li, Yu; Fan, Weidong; Ren, Peng; Wang, Kang; Wang, Junchao [Shanghai Jiao Tong Univ. (China). School of Mechanical and Power Engineering

    2013-07-01

    The oxy-fuel combustion technology is going to be a key solution for CO{sub 2} capture and sequestration. And the era of oxy-fuel combustion is approaching. However, the combustion characteristics, such as ignition, flame stability, and combustion duration, have changed because the coal particles are combusted in CO{sub 2} atmosphere. Thus, the novel design technologies of combustor used in oxy-fuel combustion technology are demanded. We have concluded several critical rules from the experiment data obtained from the coal particles combusted in a retrofitted fixed bed reactor in Ar, N{sub 2} and CO{sub 2} respectively. The coal particles are prone to be ignited but take more time to burn up in CO{sub 2} atmosphere at low temperature of 1,000-1,300 C comparing to the data obtained from N{sub 2} and Ar atmospheres under the same conditions. And when at high temperature of 1,600 C, the combustion duration of coal particles combusted in CO{sub 2} is the same with that of Ar and N{sub 2} situation. The NO{sub x} is prone to released ahead of the carbon combustion at relatively high temperature, and the priority of NO{sub x} release to Carbon combustion is aggravated as the temperature increases. The overall analysis and comparison among the three atmospheres make the novel design and layout of oxy-fuel combustor feasible. Consequently, the guidelines for these aims basing on those rules conclude from the experimental data and the relative researchers' work are discussed and a novel design of oxy-fuel burner is put forward and simulated in this paper.

  13. Copper isotope fractionation during its interaction with soil and aquatic microorganisms and metal oxy(hydr)oxides: Possible structural control

    Pokrovsky, O. S.; Viers, J.; Emnova, E. E.; Kompantseva, E. I.; Freydier, R.

    2008-04-01

    This work is aimed at quantifying the main environmental factors controlling isotope fractionation of Cu during its adsorption from aqueous solutions onto common organic (bacteria, algae) and inorganic (oxy(hydr)oxide) surfaces. Adsorption of Cu on aerobic rhizospheric ( Pseudomonas aureofaciens CNMN PsB-03) and phototrophic aquatic ( Rhodobacter sp. f-7bl, Gloeocapsa sp. f-6gl) bacteria, uptake of Cu by marine ( Skeletonema costatum) and freshwater ( Navicula minima, Achnanthidium minutissimum and Melosira varians) diatoms, and Cu adsorption onto goethite (FeOOH) and gibbsite (AlOOH) were studied using a batch reaction as a function of pH, copper concentration in solution and time of exposure. Stable isotopes of copper in selected filtrates were measured using Neptune multicollector ICP-MS. Irreversible incorporation of Cu in cultured diatom cells at pH 7.5-8.0 did not produce any isotopic shift between the cell and solution (Δ 65/63Cu(solid-solution)) within ±0.2‰. Accordingly, no systematic variation was observed during Cu adsorption on anoxygenic phototrophic bacteria ( Rhodobacter sp.), cyanobacteria ( Gloeocapsa sp.) or soil aerobic exopolysaccharide (EPS)-producing bacteria ( P. aureofaciens) in circumneutral pH (4-6.5) and various exposure times (3 min to 48 h): Δ 65Cu(solid-solution) = 0.0 ± 0.4‰. In contrast, when Cu was adsorbed at pH 1.8-3.5 on the cell surface of soil the bacterium P. aureofacienshaving abundant or poor EPS depending on medium composition, yielded a significant enrichment of the cell surface in the light isotope (Δ 65Cu (solid-solution) = -1.2 ± 0.5‰). Inorganic reactions of Cu adsorption at pH 4-6 produced the opposite isotopic offset: enrichment of the oxy(hydr)oxide surface in the heavy isotope with Δ 65Cu(solid-solution) equals 1.0 ± 0.25‰ and 0.78 ± 0.2‰ for gibbsite and goethite, respectively. The last result corroborates the recent works of Mathur et al. [Mathur R., Ruiz J., Titley S., Liermann L., Buss H. and

  14. Co-administration of morphine and oxycodone vaccines reduces the distribution of 6-monoacetylmorphine and oxycodone to brain in rats.

    Pravetoni, M; Raleigh, M D; Le Naour, M; Tucker, A M; Harmon, T M; Jones, J M; Birnbaum, A K; Portoghese, P S; Pentel, P R

    2012-06-29

    Opioid conjugate vaccines have shown promise in animal models as a potential treatment for opioid addiction. Individual vaccines are quite specific and each targets only a limited number of structurally similar opioids. Since opioid users can switch or transition between opioids, we studied a bivalent immunization strategy of combining 2 vaccines that could target several of the most commonly abused opioids; heroin, oxycodone and their active metabolites. Morphine (M) and oxycodone (OXY) haptens were conjugated to keyhole limpet hemocyanin (KLH) through tetraglycine (Gly)(4) linkers at the C6 position. Immunization of rats with M-KLH alone produced high titers of antibodies directed against heroin, 6-monoacetylmorphine (6-MAM) and morphine. Immunization with OXY-KLH produced high titers of antibodies against oxycodone and oxymorphone. Immunization with the bivalent vaccine produced consistently high antibody titers against both immunogens. Bivalent vaccine antibody titers against the individual immunogens were higher than with the monovalent vaccines alone owing, at least in part, to cross-reactivity of the antibodies. Administration of a single concurrent intravenous dose of 6-MAM and oxycodone to rats immunized with the bivalent vaccine increased 6-MAM, morphine and oxycodone retention in serum and reduced the distribution of 6-MAM and oxycodone to brain. Vaccine efficacy correlated with serum antibody titers for both monovalent vaccines, alone or in combination. Efficacy of the individual vaccines was not compromised by their combined use. Consistent with the enhanced titers in the bivalent group, a trend toward enhanced pharmacokinetic efficacy with the bivalent vaccine was observed. These data support the possibility of co-administering two or more opioid vaccines concurrently to target multiple abusable opioids without compromising the immunogenicity or efficacy of the individual components. PMID:22583811

  15. Effects of total pressure on non-grey gas radiation transfer in oxy-fuel combustion using the LBL, SNB, SNBCK, WSGG, and FSCK methods

    Chu, Huaqiang; Gu, Mingyan; Consalvi, Jean-Louis; Liu, Fengshan; Zhou, Huaichun

    2016-03-01

    The effects of total pressure on gas radiation heat transfer are investigated in 1D parallel plate geometry containing isothermal and homogeneous media and an inhomogeneous and non-isothermal CO2-H2O mixture under conditions relevant to oxy-fuel combustion using the line-by-line (LBL), statistical narrow-band (SNB), statistical narrow-band correlated-k (SNBCK), weighted-sum-of-grey-gases (WSGG), and full-spectrum correlated-k (FSCK) models. The LBL calculations were conducted using the HITEMP2010 and CDSD-1000 databases and the LBL results serve as the benchmark solution to evaluate the accuracy of the other models. Calculations of the SNB, SNBCK, and FSCK were conducted using both the 1997 EM2C SNB parameters and their recently updated 2012 parameters to investigate how the SNB model parameters affect the results under oxy-fuel combustion conditions at high pressures. The WSGG model considered is the recently developed one by Bordbar et al. [19] for oxy-fuel combustion based on LBL calculations using HITEMP2010. The total pressure considered ranges from 1 up to 30 atm. The total pressure significantly affects gas radiation transfer primarily through the increase in molecule number density and only slightly through spectral line broadening. Using the 1997 EM2C SNB model parameters the accuracy of SNB and SNBCK is very good and remains essentially independent of the total pressure. When using the 2012 EM2C SNB model parameters the SNB and SNBCK results are less accurate and their error increases with increasing the total pressure. The WSGG model has the lowest accuracy and the best computational efficiency among the models investigated. The errors of both WSGG and FSCK using the 2012 EM2C SNB model parameters increase when the total pressure is increased from 1 to 10 atm, but remain nearly independent of the total pressure beyond 10 atm. When using the 1997 EM2C SNB model parameters the accuracy of FSCK only slightly decreases with increasing the total pressure.

  16. A comparative thermodynamic, economic and risk analysis concerning implementation of oxy-combustion power plants integrated with cryogenic and hybrid air separation units

    Highlights: • Mathematical model of an integrated oxy-combustion power plant. • Comparison of a hybrid membrane–cryogenic oxygen generation plant with a cryogenic plant. • Thermodynamic analysis of the modeled cases of the plant. • Comparative economic analysis of the power plant with cryogenic and hybrid ASU. • Comparative risk analysis using a Monte Carlo method and sensitivity analysis. - Abstract: This paper presents a comparison of two types of oxy-combustion power plant that differ from each other in terms of the method of oxygen separation. For the purpose of the analysis, detailed thermodynamic models of oxy-fuel power plants with gross power of approximately 460 MW were built. In the first variant (Case 1), the plant is integrated with a cryogenic air separation unit (ASU). In the second variant (Case 2), the plant is integrated with a hybrid membrane–cryogenic installation. The models were built and optimized using the GateCycle, Aspen Plus and Aspen Custom Modeller software packages and with the use of our own computational codes. The results of the thermodynamic evaluation of the systems, which primarily uses indicators such as the auxiliary power and efficiencies of the whole system and of the individual components that constitute the unit, are presented. Better plant performance is observed for Case 2, which has a net efficiency of electricity generation that is 1.1 percentage points greater than that of Case 1. For the selected structure of the system, an economic analysis of the solutions was made. This analysis accounts for different scenarios of the functioning of the Emission Trading Scheme and includes detailed estimates of the investment costs in both cases. As an indicator of profitability, the break-even price of electricity was used primarily. The results of the analysis for the assumptions made are presented in this paper. A system with a hybrid air separation unit has slightly better economic performance. The break-even price

  17. Possibilities for improving the thermodynamic and economic characteristics of an oxy-type power plant with a cryogenic air separation unit

    In this paper the thermo-economic analysis of the oxy-type supercritical power plant integrated with the cryogenic air separation unit was presented, with the efficiency of the whole power plant of 32.26%. The reduction of energy intensity of ASU (air separation unit) was proposed by appending the membrane module. A hybrid air separation unit allows to decrease the energy intensity of oxygen production from the value of 0.226 kWh/kg O2 for the cryogenic ASU to 0.179 kWh/kg O2, for the analyzed hybrid membrane-cryogenic ASU, with an increase of the net efficiency to 33.84%. This solution causes the efficiency change by 8.7 percentage points in comparison with the reference air-fired power plant. A method of using the waste heat from the ASU and CCS (CO2 capture system) installations for the regeneration system of the steam turbine was proposed as a mean to decrease the efficiency drop. Using the waste heat in the steam turbine system causes an increase of the electric energy of the generator of turbine, and in the consequence leads to the improvement of the efficiency of the analyzed power plant by 0.5 percentage points. An economic analysis showed that the profitability of building of the oxy-type power plant in place of a conventional power plant will be higher with the price of CO2 emission allowances equal to 27.1 €/Mg CO2. All these effects of increasing the efficiency of the block can lead to lowering the cost of electricity generation by 5 €/MWh. - Highlights: • Comparison of net efficiency in the analyzed oxy and air power plant. • Analysis of possibilities of increase the power plant net efficiency. • Increase the boiler thermal efficiency by change of flue gas recirculation method. • Analysis of using the low-temperature heat from ASU and CCS installations. • Economic analysis of the analyzed power plant

  18. Adaptación de centrales térmicas de carbón al proceso de oxi-combustión

    Alcalá Carrasci¡o, Adrián

    2011-01-01

    El proceso de Oxi-combustión es una de las posibles alternativas para la generación de energía eléctrica, que permite la Captura y Almacenamiento de CO2, con el fin de cumplir los ambiciosos objetivos de reducción de emisiones. Es una prometedora tecnología que permitirá la generación de electricidad mediante combustibles fósiles durante los próximos años. Esta técnica se caracteriza por poder ser implementada en centrales térmicas convencionales, requiriendo en ellas un número mínimo de modi...

  19. Trends in activity for the water electrolyser reactions on 3d M(Ni,Co,Fe,Mn) hydr(oxy)oxide catalysts

    Subbaraman, Ram; Tripkovic, Dusan; Chang, Kee-Chul; Strmcnik, Dusan; Paulikas, Arvydas P.; Hirunsit, Pussana; Chan, Maria; Greeley, Jeff; Stamenkovic, Vojislav; Markovic, Nenad M.

    2012-06-01

    Design and synthesis of materials for efficient electrochemical transformation of water to molecular hydrogen and of hydroxyl ions to oxygen in alkaline environments is of paramount importance in reducing energy losses in water-alkali electrolysers. Here, using 3d-M hydr(oxy)oxides, with distinct stoichiometries and morphologies in the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) regions, we establish the overall catalytic activities for these reaction as a function of a more fundamental property, a descriptor, OH-M2+δ bond strength (0 ≤ δ ≤ 1.5). This relationship exhibits trends in reactivity (Mn OER) or the water dissociation product (for the HER). The successful identification of these electrocatalytic trends provides the foundation for rational design of ‘active sites’ for practical alkaline HER and OER electrocatalysts.

  20. Performance of high-velocity oxy-fuel-sprayed chromium carbide-nickel chromium coating in an actual boiler environment of a thermal power plant

    Sidhu, T.S.; Prakash, S.; Agrawal, R.D. [Industrial Technology Institute, Roorkee (India)

    2007-09-15

    The present study aims to evaluate the performance of a high-velocity oxy-fuel (HVOF)-sprayed Cr{sub 3}C{sub 2}-NiCr (chromium carbide-nickel chromium) coating on a nickel-based super-alloy in an actual industrial environment of a coal-fired boiler, with the objective to protect the boiler super-heater and reheater tubes from hot corrosion. The tests were performed in the platen super heater zone of a coal-fired boiler for 1,000 h at 900 degrees C under cyclic conditions. The Cr{sub 3}C{sub 2}-NiCr coating imparted the necessary protection to the nickel-based super alloy in the given environment. The dense and flat splat structure of the coating, and the formation of oxides of chromium and nickel and their spinels, might have protected the substrate super alloy from the inward permeation of corrosive species.

  1. Crystal structure of 4-{[(2,4-di-hydroxy-benzyl-idene)amino]-meth-yl}cyclo-hexane-carb-oxy-lic acid.

    Danish, Muhammad; Akbar, Saba; Tahir, Muhammad Nawaz; Butt, Rabia Ayub; Ashfaq, Muhammad

    2015-12-01

    In the title compound, C15H19NO4, the cyclo-hexyl ring adopts a chair conformation with both exocyclic C-C bonds in equatorial orientations. The dihedral angle between the basal plane of cyclo-hexyl ring and the 2,4-di-hydroxy-benzaldehyde moiety is 84.13 (13)°. An intra-molecular O-H⋯N hydrogen bonds closes an S(6) ring. In the crystal, Oc-H⋯Op (c = carb-oxy-lic acid, p = phenol) hydrogen bonds link the mol-ecules into [100] C(13) chains whereas an Op-H⋯Oc hydrogen bond generates [101] C(15) chains. Together, these bonds generate (010) sheets incorporating R 2 (2)(20) loops. Weak C-H⋯O and C-H⋯π inter-actions also occur. PMID:26870569

  2. Cholest-5-en-3β-yl 3-(4-eth­oxy­phen­yl)prop-2-enoate

    Bugenhagen, Bernhard; Munk, Ariane; Vill, Volkmar; Al-Jasem, Yosef; Thiemann, Thies

    2012-01-01

    In the asymmetric unit of the title compound, C38H56O3, there are two symmetry-independent mol­ecules that differ in the rotation angle along the C—O bond between the 3-(4-eth­oxy­phen­yl)prop-2-enoate and cholest-5-en-3β-yl groups by 169.3 (3)°. In both mol­ecules, steroid ring B adopts a half-chair conformation, rings A and C adopt a chair conformation and ring D exists in an envelope form. The two symmetry-independent mol­ecules pack in the crystal into separate layers parallel to (-102) with their long axis parallel to the [201] direction. Short inter­molecular C—H⋯O and C—H⋯π contacts are observed. PMID:22807885

  3. Methyl 2-methyl-4-(oxiran-2-ylmeth-oxy)-2H-1,2-benzothia-zine-3-carboxyl-ate 1,1-dioxide.

    Ahmad, Matloob; Siddiqui, Hamid Latif; Zia-Ur-Rehman, Muhammad; Elsegood, Mark R J; Weaver, George W

    2010-01-01

    In the title compound, C(14)H(15)NO(6)S, the thia-zine ring adopts a distorted half-chair conformation. The structure displays several cooperative weak inter-molecular C-H⋯O hydrogen-bonding inter-actions, giving rise to a two-dimensional sheet packing motif. The CH(2) group in the meth-oxy linker to the oxirane ring, and the CH group in that ring, exhibit twofold positional disorder. The three-membered oxirane ring is twisted approximately perpendicular with respect to thia-zine ring (dihedral angle = 60/86° for the major/minor disorder components). 1,2-Benzothia-zines of this kind have a wide range of biological activities and are mainly used as medicines in the treatment of inflammation and rheumatoid arthritis. PMID:21579762

  4. tert-Butyl N-[2-(N-isobutyl-4-meth­oxy­benzene­sulfonamido)­eth­yl]carbamate

    Xiao-Guang Bai; Ju-Xian Wang

    2014-01-01

    The title compound, C18H30N2O5S, was synthesized by the reaction of tert-butyl 2-(iso­butyl­amino)­ethyl­carbamate with p-meth­oxy­phenyl­sulfonyl chloride. In the mol­ecule, two intra­molecular C—H⋯O hydrogen bonds are observed. In the crystal, mol­ecules are linked by N—H⋯O hydrogen bonds involving the imino group N atom and the ester group O atom into chains running parallel to the b axis. The chains are further connected by C—H⋯O hydrogen bonds, forming layers parallel to the bc plane....

  5. (2E,5E)-2,5-Bis(4-hy-droxy-3-meth-oxy-benzyl-idene)cyclo-penta-none ethanol monosolvate.

    Da'i, Muhammad; Yanuar, Arry; Meiyanto, Edy; Jenie, Umar Anggara; Supardjan, Amir Margono

    2013-04-01

    In the title structure, C21H20O5·C2H5OH, the curcumine-type mol-ecule has a double E conformation for the two benzyl-idene double bonds [C=C = 1.342 (4) and 1.349 (4) Å] and is nearly planar with respect to the non-H atoms (r.m.s. deviation from planarity = 0.069 Å). The two phenolic OH groups form bifurcated hydrogen bonds with intra-molecular branches to adjacent meth-oxy O atoms and inter-molecular branches to either a neighbouring mol-ecule or an ethanol solvent mol-ecule. The ethanol O atom donates a hydrogen bond to the keto O atom. These hydrogen bonds link the constituents into layers parallel to (101) in the crystal structure. PMID:23634071

  6. Painkiller (Oxy, Vike) Facts

    ... medicine." Max talks about his addiction to prescription drugs. The addiction slowly took over his life. Read Max's story Treatment & Recovery Information Treatment and Recovery Does Drug Treatment Work? Treatment and Rehab Resources The Prescription ...

  7. Distribution of [14C]-tofenacine in rat brain after intravenous, intraperitoneal and multiple oral dosage

    The distribution of radioactivity in the rat brain at 5 min after 10 mg/kg of 14C-labelled N-methyl-2[(omethyl-a-phenylbenzyl)oxy]ethylamine, [14C]-tofenacine-hydrochloride, the active constituent of Elamolsup(R) and Tofacinesup(R), i.v. showed a heterogeneous pattern correlating well with what is known about perfusion and capillarization of brain areas. With the passage of time total brain radioactivity decreased rapidly and radioactivity was redistributed. Both processes occurred simultaneously so that a nearly homogeneous pattern was found at 1 h after i.v. administration. The outer layers of the hippocampus were then the only brain areas with a higher concentration of radioactivity. On i.p. administration of 25 mg/kg of [14C]-tofenacine-hydrochloride maximum brain radioactivity was observed at 30 min, the distribution pattern resembling that seen at 5 min after i.v. dosage. Its further time course corresponded to that of the i.v. series. On multiple oral administration of [14C]-tofenacine-hydrochloride (4 doses of 25 mg/kg at 3-h intervals), maximal radioactivity in the rat brain was observed at 120 min after the last dose. Again the distribution was heterogeneous. A model comprising a central compartment and twob brain compartments, representing areas of high and low perfusion, respectively, allows a quantitative explanation of the phenomena observed. (orig./GSE)

  8. Crystal structures of (Z)-5-[2-(benzo[b]thio­phen-2-yl)-1-(3,5-di­meth­oxy­phen­yl)ethen­yl]-1H-tetra­zole and (Z)-5-[2-(benzo[b]thio­phen-3-yl)-1-(3,4,5-tri­meth­oxy­phen­yl)ethen­yl]-1H-tetra­zole

    Penthala, Narsimha Reddy; Yadlapalli, Jaishankar K. B.; Parkin, Sean; Crooks, Peter A.

    2016-01-01

    (Z)-5-[2-(Benzo[b]thio­phen-2-yl)-1-(3,5-di­meth­oxy­phen­yl)ethen­yl]-1H-tetrazole methanol monosolvate, C19H16N4O2S·CH3OH, (I), was prepared by the reaction of (Z)-3-(benzo[b]thio­phen-2-yl)-2-(3,5-di­meth­oxy­phen­yl)acrylo­nitrile with tri­butyl­tin azide via a [3 + 2]cyclo­addition azide condensation reaction. The structurally related compound (Z)-5-[2-(benzo[b]thio­phen-3-yl)-1-(3,4,5-tri­meth­oxy­phen­yl)ethen­yl]-1H-tetra­zole, C20H18N4O3S, (II), was prepared by the reaction of (Z)-3-(benzo[b]thio­phen-3-yl)-2-(3,4,5-tri­meth­oxy­phen­yl)acrylo­nitrile with tri­butyl­tin azide. Crystals of (I) have two mol­ecules in the asymmetric unit (Z′ = 2), whereas crystals of (II) have Z′ = 1. The benzo­thio­phene rings in (I) and (II) are almost planar, with r.m.s deviations from the mean plane of 0.0084 and 0.0037 Å in (I) and 0.0084 Å in (II). The tetra­zole rings of (I) and (II) make dihedral angles with the mean planes of the benzo­thio­phene rings of 88.81 (13) and 88.92 (13)° in (I), and 60.94 (6)° in (II). The di­meth­oxy­phenyl and tri­meth­oxy­phenyl rings make dihedral angles with the benzo­thio­phene rings of 23.91 (8) and 24.99 (8)° in (I) and 84.47 (3)° in (II). In both structures, mol­ecules are linked into hydrogen-bonded chains. In (I), these chains involve both tetra­zole and methanol, and are parallel to the b axis. In (II), mol­ecules are linked into chains parallel to the a axis by N—H⋯N hydrogen bonds between adjacent tetra­zole rings. PMID:27308011

  9. Influence of the X-site composition on tourmaline's crystal structure: investigation of synthetic K-dravite, dravite, oxy-uvite, and magnesio-foitite using SREF and Raman spectroscopy

    Berryman, E. J.; Wunder, B.; Ertl, A.; Koch-Müller, M.; Rhede, D.; Scheidl, K.; Giester, G.; Heinrich, W.

    2016-02-01

    The crystal structures of synthetic K-dravite [XKYMg 3 Z Al 6 T Si6O18(BO3) 3 V (OH) 3 W (OH)], dravite [XNaYMg 3 Z Al 6 T Si6O18(BO3) 3 V (OH) 3 W (OH)], oxy-uvite [XCaYMg 3 Z Al 6 T Si6O18(BO3) 3 V (OH) 3 W O], and magnesio-foitite [X☐Y(Mg2Al)ZAl 6 T Si6O18(BO3) 3 V (OH) 3 W (OH)] are investigated by polarized Raman spectroscopy, single-crystal structure refinement (SREF), and powder X-ray diffraction. The use of compositionally simple tourmalines characterized by electron microprobe analysis facilitates the determination of site occupancy in the SREF and band assignment in the Raman spectra. The synthesized K-dravite, oxy-uvite, and magnesio-foitite have significant Mg-Al disorder between their octahedral sites indicated by their respective average and bond lengths. The Y- and Z-site compositions of oxy-uvite (YMg1.52Al1.48(10) and ZAl4.90Mg1.10(15)) and magnesio-foitite (YAl1.62Mg1.38(18) and ZAl4.92Mg1.08(24)) are refined from the electron densities at each site. The Mg-Al ratio of the Y and Z sites is also determined from the relative integrated peak intensities of the Raman bands in the O-H stretching vibrational range (3250-3850 cm-1), producing values in good agreement with the SREF data. The unit cell volume of tourmaline increases from magnesio-foitite (1558.4(3) Å3) to dravite (1569.5(4)-1571.7(3) Å3) to oxy-uvite (1572.4(2) Å3) to K-dravite (1588.1(2) Å3), mainly due to lengthening of the crystallographic c-axis. The increase in the size of the X-site coordination polyhedron from dravite (Na) to K-dravite (K) is accommodated locally in the crystal structure, resulting in the shortening of the neighboring O1- H1 bond. In oxy-uvite, Ca2+ is locally associated with a deprotonated W (O1) site, whereas vacant X sites are neighbored by protonated W ( O1) sites. Increasing the size of the X-site-occupying ion does not detectably affect bonding between the other sites; however, the higher charge of Ca and the deprotonated W ( O1) site in oxy-uvite are

  10. Crystal structure of a nucleoside model for the inter-strand cross-link formed by the reaction of 2'-de-oxy-guanosine and an abasic site in duplex DNA.

    Catalano, Michael J; Ruddraraju, Kasi Viswanatharaju; Barnes, Charles L; Gates, Kent S

    2016-05-01

    The title compound, 9-[(2R,4S,5R)-4-hy-droxy-5-(hy-droxy-meth-yl)tetra-hydro-furan-2-yl]-2-{[(2R,4S,5R)-4-meth-oxy-5-(meth-oxy-meth-yl)tetra-hydro-furan-2-yl]amino}-1H-purin-6(9H)-one, C17H25N5O7, crystallizes with two independent mol-ecules (A and B) in the asymmetric unit. In the crystal, the guanosine moieties of mol-ecules A and B are linked by N-H⋯N and O-H⋯N hydrogen-bonding inter-actions, forming ribbons which are stacked to form columns along [100]. These columns are then linked by O-H⋯O hydrogen bonds between the ribose moieties and numerous C-H⋯O inter-actions to complete the three-dimensional structure. PMID:27308004

  11. catena-Poly[[[{5,5′-dimeth­oxy-2,2′-[ethane-1,2-diylbis(nitrilo­methyl­idyne)]diphenolato}manganese(III)]-μ-acetato] methanol monosolvate

    Assey, Gervas E.; Butcher, Anand M.; Butcher, Ray J.; Gultneh, Yilma

    2010-01-01

    The title MnIII compound, {[Mn(C18H18N2O4)(CH3COO)]·CH3OH} n , was synthesized by a reaction between mangan­ese(II) acetate and ethyl­enebis(4-meth­oxy­salicylaldimine). The structure is made up of bis­(4-meth­oxy­salicyldene)ethyl­enediaminatomanganese(III) units bridged by acetate groups, with Mn—N = 1.9786 (9), Mn—O = 1.8784 (10) and Mn—Oacetate = 2.056 (9) and 2.2571 (9) Å, forming a one dimensional polymer (–Mn–acetate–Mn–acetate–) along [100]. The MnIII atom is in a Jahn–Teller-distorte...

  12. Scientific Opinion on the substantiation of a health claim related to OXY 280 and reduction of body weight pursuant to Article 13(5 of Regulation (EC No 1924/2006

    EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA

    2012-12-01

    Full Text Available Following an application from Actina, submitted pursuant to Article 13(5 of Regulation (EC No 1924/2006 via the Competent Authority of Belgium, the Panel on Dietetic Products, Nutrition and Allergies (NDA was asked to deliver an opinion on the scientific substantiation of a health claim related to OXY 280 and reduction of body weight. The food constituent that is the subject of the health claim, OXY 280, which is a powder composed of kidney bean, olive and rosemary extracts, is sufficiently characterised. The claimed effect, reduction of body weight, is a beneficial physiological effect for overweight subjects. One unpublished human intervention study was provided by the applicant as pertinent to the health claim. This randomised, double-blind, placebo-controlled study investigated the effect of OXY 280 vs placebo on body weight, BMI, and waist, hip and thigh circumferences in 60 overweight subjects. The Panel notes that the results of between-group comparisons with respect to changes in the outcome variables assessed in this study were not provided. The Panel considers that the data as analysed do not allow the evaluation of the effect of the food constituent on changes in body weight relative to the placebo, and that no conclusions can be drawn from this study for the scientific substantiation of the claim. The Panel notes that no studies from which conclusions could be drawn for the scientific substantiation of the claim were provided by the applicant. The Panel concludes that a cause and effect relationship has not been established between the consumption of OXY 280 and a reduction in body weight.

  13. Molecular identification of CTX-M and blaOXY/K1 β-lactamase genes in Enterobacteriaceae by sequencing of universal M13-sequence tagged PCR-amplicons

    Tärnberg Maria

    2009-01-01

    Full Text Available Abstract Background Plasmid encoded blaCTX-M enzymes represent an important sub-group of class A β-lactamases causing the ESBL phenotype which is increasingly found in Enterobacteriaceae including Klebsiella spp. Molecular typing of clinical ESBL-isolates has become more and more important for prevention of the dissemination of ESBL-producers among nosocomial environment. Methods Multiple displacement amplified DNA derived from 20 K. pneumoniae and 34 K. oxytoca clinical isolates with an ESBL-phenotype was used in a universal CTX-M PCR amplification assay. Identification and differentiation of blaCTX-M and blaOXY/K1 sequences was obtained by DNA sequencing of M13-sequence-tagged CTX-M PCR-amplicons using a M13-specific sequencing primer. Results Nine out of 20 K. pneumoniae clinical isolates had a blaCTX-M genotype. Interestingly, we found that the universal degenerated primers also amplified the chromosomally located K1-gene in all 34 K. oxytoca clinical isolates. Molecular identification and differentiation between blaCTX-M and blaOXY/K1-genes could only been achieved by sequencing of the PCR-amplicons. In silico analysis revealed that the universal degenerated CTX-M primer-pair used here might also amplify the chromosomally located blaOXY and K1-genes in Klebsiella spp. and K1-like genes in other Enterobacteriaceae. Conclusion The PCR-based molecular typing method described here enables a rapid and reliable molecular identification of blaCTX-M, and blaOXY/K1-genes. The principles used in this study could also be applied to any situation in which antimicrobial resistance genes would need to be sequenced.

  14. SWEEP Project RAT

    Ibsen, Lars Bo; Madsen, Søren; Petersen, L. B.;

    This report presents the results from the design analyses made for the clustered suction caisson used as foundation for a Riser Access Tower (RAT). The RAT is intended built next to the K15-FA-1 Platform in the Dutch Sector of the North Sea....

  15. Crystal structure of 3-meth­oxy­carbonyl-2-(4-meth­oxy­phen­yl)-8-oxo-1-aza­spiro[4.5]deca-1,6,9-trien-1-ium-1-olate

    Martins, Lucimara Julio; Simoni, Deborah de Alencar; Aparicio, Ricardo; Coelho, Fernando

    2014-01-01

    The title compound, C18H17NO5, was prepared by a synthetic strategy based on the Heck reaction from Morita–Baylis–Hillman adducts. The five-membered ring adopts a slightly twisted conformation on the Ca—Cm (a = aromatic and m = methyl­ene) bond. The dihedral angle between the five-membered ring and the spiro aromatic ring is 89.35 (7)°; that between the five-membered ring and the 4-meth­oxy­benzene ring is 4.65 (7)°. Two short intra­molecular C—H⋯O contacts occur. In the crystal, mol­ecules are linked by C—H⋯O hydrogen bonds to generate a three-dimensional network. PMID:25484828

  16. Rat liver insulin receptor

    Using insulin affinity chromatography, the authors have isolated highly purified insulin receptor from rat liver. When evaluated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis under reducing conditions, the rat liver receptor contained the M/sub r/ 125,000 α-subunit, the M/sub r/ 90,000 β-subunit, and varying proportions of the M/sub r/ 45,000 β'-subunit. The specific insulin binding of the purified receptor was 25-30 μg of 125I-insulin/mg of protein, and the receptor underwent insulin-dependent autophosphorylation. Rat liver and human placental receptors differ from each other in several functional aspects: (1) the adsorption-desorption behavior from four insulin affinity columns indicated that the rat liver receptor binds less firmly to immobilized ligands; (2) the 125I-insulin binding affinity of the rat liver receptor is lower than that of the placental receptor; (3) partial reduction of the rat liver receptor with dithiothreitol increases its insulin binding affinity whereas the binding affinity of the placental receptor is unchanged; (4) at optimal insulin concentration, rat liver receptor autophosphorylation is stimulated 25-50-fold whereas the placental receptor is stimulated only 4-6-fold. Conversion of the β-subunit to β' by proteolysis is a major problem that occurs during exposure of the receptor to the pH 5.0 buffer used to elute the insulin affinity column. Proteolytic destruction and the accompanying loss of insulin-dependent autophosphorylation can be substantially reduced by proteolysis inhibitors. In summary, rat liver and human placental receptors differ functionally in both α- and β-subunits. Insulin binding to the α-subunit of the purified rat liver receptor communicates a signal that activates the β-subunit; however, major proteolytic destruction of the β-subunit does not affect insulin binding to the α-subunit

  17. Cholesteric Liquid-Crystal Copolyester, Poly[oxycarbonyl- 1,4-phenylene- oxy - 1,4 terephthaloyl- oxy- 1,4-phenylenecarbonyloxy (1,2-dodecane] [C34H36O8]n, Synthesized from Racemic Materials: Kinetics, Structure and Optical Characterization.

    Mercedes Pérez Méndez

    2015-07-01

    Full Text Available The cholesteric liquid-crystal poly[oxycarbonyl-1,4-phenylene-oxy-1,4 terephthaloyl-oxy-1,4-phenylenecarbonyloxy(1,2-dodecane] [C34H36O8]n, named PTOBDME, synthesized by polycondensation reaction from equimolar quantities of TOBC and the racemic mixture of glycol (R-S-1,2 dodecanediol, exhibits unexpected optical activity and chiral morphology. The structure of racemic-PTOBDME, under different polymerization kinetics conditions, is analyzed by conventional NMR techniques and compared with those of polymer enantiomers R-PTOBDME and S-PTOBDME obtained starting R(+1,2 and S(-1,2-dodecanediol respectively. Molecular models based on the NMR signals intensities are proposed. The optical activity of racemicPTOBDME is evaluated by measuring the ORD values during kinetics study, and compared to the chiral polymers. Each enantiomeric polymer seems to present the same stereoregular head-tail, isotactic structure than the racemic, which we explain by the higher reactivity of the primary hydroxyl than the secondary one in the glycol through polycondensation. For each enantiomer, two independent sets of signals were observed by NMR, explained as two diastereomeric helical conformers: gg and gt, related with two possible staggered conformations, along the copolymer backbone. Chirality in racemic-PTOBDME is proposed to be due to the kinetic resolution of a preferable helical diastereomer, such as Sgt, with respect to the possible four forms, while the R/S ratio of asymmetric carbon atoms remained 50:50. Chiral amplification is observed in R-PTOBDME and S-PTOBDME due to a helical screw sense excess. Optimum yield was obtained for racemic PTOBDME, after 120 minutes polycondensated and decanted in toluene for 24 hours. Two weeks later a second fraction precipitated from the toluene mother liquor with 67.6% chiral excess. After eight months and two weeks a third fraction precipitated with 85.2% chiral excess.

  18. Comparison of in vitro behavior of as-sprayed, alkaline-treated and collagen-treated bioceramic coatings obtained by high velocity oxy-fuel spray

    Hydroxyapatite (HAp)–TiO2 samples obtained using high velocity oxy-fuel spray (HVOF), that had previously shown excellent mechanical behaviour, were innovatively surface treated in order to improve their biological performance. The chosen treatments were an alkaline treatment to increase –OH radicals density on the surface (especially on TiO2 zones), and a collagen treatment to bond collagen fibrils to the –OH radicals present in hydroxyapatite. These coatings were analysed using scanning electron microscopy, energy-dispersive X-ray spectroscopy and infrared spectroscopy, and tested for human osteoblast biocompatibility and functionality. In the case of the alkaline treatment, although the –OH radicals density did not increase compared to the as-sprayed coatings, a nanostructured layer of sodium hydroxycarbonate precipitated on the surface, thus improving biological behaviour due to the nanoroughness effect. For the collagen-treated samples, collagen fibrils appeared well-adhered to the surface, and in vitro cell culture tests showed that these surfaces were much more conducive to cell adhesion and differentiation than the as-sprayed and alkaline-treated samples. These results pointed to collagen treatment as a very promising method to improve bioactivity of HAp–TiO2 thermal-sprayed coatings.

  19. Structural Properties and Biological Prediction of ({[(1E-3-(1H-Imidazol-1-yl-1-phenylpropylidene] amino}oxy(4-methylphenylmethanone: An In Silico Approach

    Maha S. Almutairi

    2015-12-01

    Full Text Available Bioactive molecules are playing essential role in the field of drug discovery and various pharmaceutical applications. Vibrational spectral investigations of the anti-Candida agent ({[(1E-3-(1H-imidazol-1-yl-1-phenylpropylidene]amino}oxy(4-methylphenylmethanone ((1E-IPMM have been recorded and analyzed to understand its structural geometry, inter- and intra-molecular interactions. The equilibrium geometry, harmonic vibrational wavenumber, natural bond orbital (NBO and Frontier orbital energy analyses have been carried out with the help of density functional theory with B3LYP/6-311++G(d,p level of theory. The detailed vibrational assignments for the title molecule were performed on the basis of potential energy distribution analysis in order to unambiguously predict its modes. The calculated wavenumbers had good agreement with the experimental values. NBO analysis has confirmed the intramolecular charge transfer interactions. The predicted docking binding energy gave insight into the possible biological activity of the title molecule.

  20. Comparison of in vitro behavior of as-sprayed, alkaline-treated and collagen-treated bioceramic coatings obtained by high velocity oxy-fuel spray

    Melero, H., E-mail: hortensia.melero.correas@gmail.com [Thermal Spray Centre, Universitat de Barcelona, Martí i Franqués, 1, 08028 Barcelona (Spain); Garcia-Giralt, N. [URFOA, IMIM (Institut Hospital del Mar d’Investigacions Mèdiques), RETICEF, Doctor Aiguader, 80, 08003 Barcelona (Spain); Fernández, J. [Thermal Spray Centre, Universitat de Barcelona, Martí i Franqués, 1, 08028 Barcelona (Spain); Díez-Pérez, A. [URFOA, IMIM (Institut Hospital del Mar d’Investigacions Mèdiques), RETICEF, Doctor Aiguader, 80, 08003 Barcelona (Spain); Servei de Medicina Interna, Hospital del Mar, Barcelona (Spain); Guilemany, J.M. [Thermal Spray Centre, Universitat de Barcelona, Martí i Franqués, 1, 08028 Barcelona (Spain)

    2014-07-01

    Hydroxyapatite (HAp)–TiO{sub 2} samples obtained using high velocity oxy-fuel spray (HVOF), that had previously shown excellent mechanical behaviour, were innovatively surface treated in order to improve their biological performance. The chosen treatments were an alkaline treatment to increase –OH radicals density on the surface (especially on TiO{sub 2} zones), and a collagen treatment to bond collagen fibrils to the –OH radicals present in hydroxyapatite. These coatings were analysed using scanning electron microscopy, energy-dispersive X-ray spectroscopy and infrared spectroscopy, and tested for human osteoblast biocompatibility and functionality. In the case of the alkaline treatment, although the –OH radicals density did not increase compared to the as-sprayed coatings, a nanostructured layer of sodium hydroxycarbonate precipitated on the surface, thus improving biological behaviour due to the nanoroughness effect. For the collagen-treated samples, collagen fibrils appeared well-adhered to the surface, and in vitro cell culture tests showed that these surfaces were much more conducive to cell adhesion and differentiation than the as-sprayed and alkaline-treated samples. These results pointed to collagen treatment as a very promising method to improve bioactivity of HAp–TiO{sub 2} thermal-sprayed coatings.

  1. TAFF and vortex glass state in a niobium oxy-nitride Nb(N0.98O0.02)

    Venkateshwarlu, D.; Ganesan, V.; Ohashi, Y.; Kikkawa, S.; Yakhmi, J. V.

    2015-05-01

    Resistivity broadening of niobium oxy-nitride [Nb(N0.98O0.02)] is analyzed in terms of fluctuation conductivity, thermally activated flux flow (TAFF) and vortex glass study in magnetic fields up to 14 T. Zero field fluctuation analysis of excess conductivity using the Aslamzov-Larkin theory shows an indication of a 3D character that is further supported by the lowest Landau level (LLL) scaling. We could obtain a clear vortex glass region from an extended analysis of the resistivity data. Different regions of interest are estimated that include vortex glass and vortex liquids of the phase diagram. The TAFF has been analyzed using conventional Arrhenius relation, as well as its modified version that includes a temperature- and field-dependent pre-factor. While the conventional TAFF scaling is well suited for the present system, the modified version yields deeper insight into the material parameters of interest. Ginzburg number, coherence length, critical exponents related to the vortex glass transition, etc, are estimated and discussed.

  2. Trends in activity for the water electrolyzer reactions on 3d-M(Ni,Co,Fe,Mn)-hydr(oxy)oxide catalysts.

    Subbaraman, R.; Tripkovic, D.; Chang, K-C.; Strmcnik, D.; Paulikas, A. P.; Hirunsit, P.; Chan, M.; Greeley, J.; Stamenkovic, V.; Markovic, N. M. (Center for Nanoscale Materials); ( MSD); ( NE)

    2012-01-01

    Design and synthesis of materials for efficient electrochemical transformation of water to molecular hydrogen and of hydroxyl ions to oxygen in alkaline environments is of paramount importance in reducing energy losses in water-alkali electrolysers. Here, using 3d-M hydr(oxy)oxides, with distinct stoichiometries and morphologies in the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) regions, we establish the overall catalytic activities for these reaction as a function of a more fundamental property, a descriptor, OH-M{sup 2+{delta}} bond strength (0 {le} {delta} {le} 1.5). This relationship exhibits trends in reactivity (Mn < Fe < Co < Ni), which is governed by the strength of the OH-M{sup 2+{delta}} energetic (Ni < Co < Fe < Mn). These trends are found to be independent of the source of the OH, either the supporting electrolyte (for the OER) or the water dissociation product (for the HER). The successful identification of these electrocatalytic trends provides the foundation for rational design of 'active sites' for practical alkaline HER and OER electrocatalysts.

  3. Evaluation of Die-Soldering and Erosion Resistance of High Velocity Oxy-Fuel Sprayed MoB-Based Cermet Coatings

    Khan, Faisal Farooq; Bae, Gyuyeol; Kang, Kicheol; Na, Hyuntaek; Kim, Junghwan; Jeong, Taeho; Lee, Changhee

    2011-09-01

    Soldering and erosion are two of the biggest serious problems faced in the die-casting industries. Cermet coatings utilized by high-velocity oxy-fuel (HVOF) spray technology have been developed in an attempt to overcome these problems. MoB-based cermet feedstock powders (MoB/NiCr and MoB/CoCr) were deposited on SKD61 (AISI H-13) substrates used as a preferred die (mold) material. Microstructural and mechanical properties of the coatings have been characterized by scanning electron microscopy, x-ray diffraction, Romulus bond strength test, and Vickers microhardness test. The durability of these coatings on cylindrical specimens against soldering also has been investigated by immersing in molten aluminum alloy (ADC-12) for 25 h at 670 °C and subsequently, compared with that of NiCr and CoMoCr coatings. Both types of MoB-based cermet coatings have shown high soldering resistance as negligible intermetallic formation occurred during the immersion test. This result is attributed to the existence of multiple inert borides in the coatings. The coatings also showed excellent mechanical properties. MoB/NiCr, in particular, showed higher bond strength, hardness, and wear resistance than MoB/CoCr. This suggests that MoB/NiCr will show higher durability than MoB/CoCr, NiCr, and CoMoCr during high pressure die-casting of aluminum alloys.

  4. Formation of amorphous and nanocrystalline phases in high velocity oxy-fuel thermally sprayed a Fe-Cr-Si-B-Mn alloy

    High velocity oxy-fuel (HVOF) thermal spray was used to deposit a Fe-Cr-Si-B alloy coating onto stainless steel (1Cr18Ni9Ti) substrate. Microstructures of the powder and the coating were investigated by X-ray diffraction (XRD), scanning election microscopy (SEM), transmission election microscopy (TEM) and differential scanning calorimeter (DSC). The coating had layered morphologies due to the deposition and solidification of successive molten or half-molten splats. The microstructures of the coating consisted of a Fe-Cr-rich matrix and several kinds of borides. The Fe-Cr-rich matrix contained both amorphous phase and nanocrystalline grains with a size of 10-50 nm. The crystallization temperature of the amorphous phase was about 605 deg. C. The formation of the amorphous phase was attributed to the high cooling rates of molten droplets and the proper powder compositions by effective addition of Cr, Mn, Si and B. The nanocrystalline grains could result from crystallization in amorphous region or interface of the amorphous phase and borides by homogeneous and heterogeneous nucleation

  5. Comparison of the Mechanical and Electrochemical Properties of WC-25Co Coatings Obtained by High Velocity Oxy-Fuel and Cold Gas Spraying

    Couto, M.; Dosta, S.; Fernández, J.; Guilemany, J. M.

    2014-12-01

    Cold gas spray (CGS) coatings were previously produced by spraying WC-25Co cermet powders onto Al7075-T6 and low-carbon steel substrates. Unlike conventional flame spray techniques (e.g., high-velocity oxy-fuel; HVOF), no melting of the powder occurs; the particles are deformed and bond together after being sprayed by a supersonic jet of compressed gas, thereby building up several layers and forming a coating. WC-Co cermets are used in wear-resistant parts, because of their combination of mechanical, physical, and chemical properties. XRD tests were previously run on the initial powder and the coatings to determine possible phase changes during spraying. The bonding strength of the coatings was measured by adhesion tests. Here, WC-25Co coatings were also deposited on the same substrates by HVOF spraying. The wear resistance and fracture toughness of the coatings obtained previously by CGS and the HVOF coatings obtained here were studied. Their corrosion resistance was determined by electrochemical measurements. It was possible to achieve thick, dense, and hard CGS coatings on Al7075-T6 and low-carbon steel substrates, with better or the same mechanical and electrochemical properties as those of the HVOF coatings; making the former a highly competitive method for producing WC-25Co coatings.

  6. High-Temperature Behavior of a High-Velocity Oxy-Fuel Sprayed Cr3C2-NiCr Coating

    Kaur, Manpreet; Singh, Harpreet; Prakash, Satya

    2012-08-01

    High-velocity oxy-fuel (HVOF) sprayed coatings have the potential to enhance the high-temperature oxidation, corrosion, and erosion-corrosion resistance of boiler steels. In the current work, 75 pct chromium carbide-25 pct (nickel-20 pct chromium) [Cr3C2-NiCr] coating was deposited on ASTM SA213-T22 boiler steel using the HVOF thermal spray process. High-temperature oxidation, hot corrosion, and erosion-corrosion behavior of the coated and bare steel was evaluated in the air, molten salt [Na2SO4-82 pct Fe2(SO4)3], and actual boiler environments under cyclic conditions. Weight-change measurements were taken at the end of each cycle. Efforts were made to formulate the kinetics of the oxidation, corrosion, and erosion-corrosion. X-ray diffraction (XRD) and field-emission scanning electron microscopy (FE-SEM)/energy dispersive spectroscopy (EDS) techniques were used to analyze the oxidation products. The coating was found to be intact and spallation free in all the environments of the study in general, whereas the bare steel suffered extensive spallation and a relatively higher rate of degradation. The coating was found to be useful to enhance the high-temperature resistance of the steel in all the three environments in this study.

  7. Dominant effect of carbide rebounding on the carbon loss during high velocity oxy-fuel spraying of Cr3C2-NiCr

    Cr3C2-25% NiCr coatings were deposited by high velocity oxy-fuel (HVOF) spraying process using two commercial powders. The microstructure of the deposited coating was characterized by scanning electron microscopy. The carbon contents in both the deposited coatings and the collected powders were characterized by chemical analysis to clarify the main mechanism controlling the carbon loss during deposition of Cr3C2-NiCr coating by HVOF spraying. The results revealed that the carbon loss in the collected powders was much lower than that in the coatings. A model involved in a solid-liquid two-phase particle deposition behavior and rebound-off of large carbide particles during splatting was proposed to explain the effect of droplet conditions including carbide particle size on the carbon loss during deposition of Cr3C2-NiCr. It was suggested that the rebound-off of larger carbide particles when the two-phase droplet impacts on the surface is main mechanism responsible for overall high carbon loss during HVOF spraying of Cr3C2-NiCr

  8. Improvement in wear and corrosion resistance of AISI 1020 steel by high velocity oxy-fuel spray coating containing Ni-Cr-B-Si-Fe-C

    Prince, M.; Thanu, A. Justin; Gopalakrishnan, P.

    2012-04-01

    In this investigation, AISI 1020 low carbon steel has been selected as the base material. The Ni based super alloy powder NiCrBSiFeC was sprayed on the base material using high velocity oxy-fuel spraying (HVOF) technique. The thickness of the coating was approximately 0.5 mm (500 μm). The coating was characterized using optical microscopy, Vickers microhardness testing, X-ray diffraction technique and scanning electron microscopy. Dry sliding wear tests were carried out at 3 m/s sliding speed under the load of 10 N for 1000 m sliding distance at various temperatures i.e., 35° C, 250° C and 350° C. The corrosion test was carried out in 1 M copper chloride in acetic acid solution. The polarization studies were also conducted for both base material and coating. The improvement in microhardness from 1.72 GPa (175 HV0.05) to 10.54 GPa (1075 HV0.05) was observed. The coatings exhibited 3-6 times improved wear resistance as compared with base material. Also, the corrosion rate was reduced by 3.5 times due to the presence of coatings.

  9. Microstructural Characterization and Wear Behavior of Nano-Boride Dispersed Coating on AISI 304 Stainless Steel by Hybrid High Velocity Oxy-Fuel Spraying Laser Surface Melting

    Sharma, Prashant; Majumdar, Jyotsna Dutta

    2015-07-01

    The current study concerns the detailed microstructural characterization and investigation of wear behavior of nano-boride dispersed coating developed on AISI 304 stainless steel by high velocity oxy-fuel spray deposition of nickel-based alloy and subsequent laser melting. There is a significant refinement and homogenization of microstructure with improvement in microhardness due to laser surface melting (1200 VHN as compared to 945 VHN of as-sprayed and 250 VHN of as-received substrate). The high temperature phase stability of the as-coated and laser melted surface has been studied by differential scanning calorimeter followed by detailed phase analysis at room and elevated temperature. There is a significant improvement in wear resistance of laser melted surface as compared to as-sprayed and the as-received one due to increased hardness and reduced coefficient of friction. The mechanism of wear has been investigated in details. Corrosion resistance of the coating in a 3.56 wt pct NaCl solution is significantly improved (4.43 E-2 mm/year as compared to 5 E-1 mm/year of as-sprayed and 1.66 mm/year of as-received substrate) due to laser surface melting as compared to as-sprayed surface.

  10. Reduction of emission when applying thermal separation processes in the dismantling of nuclear facilities - oxy-fuel gas and plasma arc cutting

    Plasma arc cutting and laser beam cutting was used for the studies with the goal of significantly reducing material emission by changing the operating and equipment parameters. Some separations using the oxy-fuel gas cutting process served the purpose of providing a guide for determining which factors can most effectively reduce emission. The separation experiments were carried out with specimens of R-St 37-2, 10 mm thick, as well as of X 6 CrNi 18 10 steel 5, 10, 15 and 20 mm thick. In all cases, lowering speed and the amount of gas proved at first to be effective measures to check material emission. It was also possible to achieve adherence of molten mass and slag on the flank of the joint with excessive icicling. When the plasma separates the CrNi steel, it is possible to increase emission reduction additionally by using an argon/hydrogen mixture instead of nitrogen as a cutting gas. (orig./DG)

  11. Experimental and numerical evaluation of the performance of supersonic two-stage high-velocity oxy-fuel thermal spray (Warm Spray) gun

    Katanoda, H.; Morita, H.; Komatsu, M.; Kuroda, S.

    2011-03-01

    The water-cooled supersonic two-stage high-velocity oxy-fuel (HVOF) thermal spray gun was developed to make a coating of temperature-sensitive material, such as titanium, on a substrate. The gun has a combustion chamber (CC) followed by a mixing chamber (MC), in which the combustion gas is mixed with the nitrogen gas at room temperature. The mixed gas is accelerated to supersonic speed through a converging-diverging (C-D) nozzle followed by a straight passage called the barrel. This paper proposes an experimental procedure to estimate the cooling rate of CC, MC and barrel separately. Then, the mathematical model is presented to predict the pressure and temperature in the MC for the specific mass flow rates of fuel, oxygen and nitrogen by assuming chemical equilibrium with water-cooling in the CC and MC, and frozen flow with constant specific heat from stagnant condition to the throat in the CC and MC. Finally, the present mathematical model was validated by comparing the calculated and measured stagnant pressures of the CC of the two-stage HVOF gun.

  12. Magnetic properties of layered rare-earth oxy-carbonates Ln2O2CO3 (Ln=Nd, Sm, and Dy)

    Arjun, U.; Brinda, K.; Padmanabhan, M.; Nath, R.

    2016-08-01

    Polycrystalline samples of rare-earth oxy-carbonates Ln2O2CO3 (Ln=Nd, Sm, and Dy) are synthesized and their structural and magnetic properties are investigated. All of them crystallize in a hexagonal structure with space group P63 / mmc. They form a double layered structure with frustrated triangular arrangement of rare-earth magnetic ions. An antiferromagnetic transition is observed at TN ~ 1.25 K , 0.61 K, and 1.21 K for Nd2O2CO3, Sm2O2CO3, and Dy2O2CO3, respectively. From the analysis of magnetic susceptibility, the value of the Curie-Weiss temperature θCW is obtained to be ~21.7 K, 18 K, and 10.6 K for Nd2O2CO3, Sm2O2CO3, and Dy2O2CO3, respectively. The magnetic frustration parameter f(= |θCW | /TN) is calculated to be ~17.4, 31, and 8.8 for Nd2O2CO3, Sm2O2CO3, and Dy2O2CO3, respectively, which indicates that Sm2O2CO3 is strongly frustrated compared to its Nd and Dy analogues.

  13. Near-infrared oxymeter biosensor prototype for non-invasive in vivo analysis of rat brain oxygenation: effects of drugs of abuse

    Crespi, F.; Donini, M.; Bandera, A.; Congestri, F.; Formenti, F.; Sonntag, V.; Heidbreder, C.; Rovati, L.

    2006-07-01

    The feasibility of non-invasive analysis of brain activities was studied in the attempt to overcome the major limitation of actual in vivo methodologies, i.e. invasiveness. Optic fibre probes were used as the optical head of a novel, highly sensitive near-infrared continuous wave spectroscopy (CW-NIR) instrument. This prototype was designed for non-invasive analysis of the two main forms of haemoglobin: oxy-haemoglobin (HbO2) and deoxy-haemoglobin (Hb), chromophores present in biological tissues. It was tested in peripheral tissue (human gastrocnemius muscle) and then reset to perform the measurement on rat brain. In animal studies, the optical head was firmly placed using stereotaxic apparatus upon the sagittal line of the head of anaesthetized adult rats, without any surgery. Then pharmacological treatments with saline (300 µl s.c.) amphetamine (2 mg kg-1) or nicotine (0.4 mg kg-1) were performed. Within 10-20 min amphetamine substantially increased HbO2 and reduced Hb control levels. Nicotine produced a rapid initial increase followed by a decrease in HbO2. In contrast to amphetamine, nicotine treatment also reduced Hb and blood volume. These results support the capacity of our CW-NIR prototype to measure non-invasively HbO2 and Hb levels in the rat brain, that are markers of the degree of tissue oxygenation, thus providing an index of blood levels and therefore of brain metabolism.

  14. Pilot-Scale Demonstration of a Novel, Low-Cost Oxygen Supply Process and its Integration with Oxy-Fuel Coal-Fired Boilers

    Krish Krishnamurthy; Divy Acharya; Frank Fitch

    2008-09-30

    In order to achieve DOE targets for carbon dioxide capture, it is crucial not only to develop process options that will generate and provide oxygen to the power cycle in a cost-effective manner compared to the conventional oxygen supply methods based on cryogenic air separation technology, but also to identify effective integration options for these new technologies into the power cycle with carbon dioxide capture. The Linde/BOC developed Ceramic Autothermal Recovery (CAR) process remains an interesting candidate to address both of these issues by the transfer of oxygen from the air to a recycled CO{sub 2} rich flue-gas stream in a cyclic process utilizing the high temperature sorption properties of perovskites. Good progress was made on this technology in this project, but significant challenges remain to be addressed before CAR oxygen production technology is ready for commercial exploitation. Phase 1 of the project was completed by the end of September 2008. The two-bed 0.7 tons/day O2 CAR process development unit (PDU) was installed adjacent to WRI's pilot scale coal combustion test facility (CTF). Start-up and operating sequences for the PDU were developed and cyclic operation of the CAR process demonstrated. Controlled low concentration methane addition allowed the beds to be heated up to operational temperature (800-900 C) and then held there during cyclic operation of the 2-bed CAR process, in this way overcoming unavoidable heat losses from the beds during steady state operation. The performance of the PDU was optimized as much as possible, but equipment limitations prevented the system from fully achieving its target performance. Design of the flue gas recirculation system to integrate CAR PDU with the CTF and the system was completed and integrated tests successfully performed at the end of the period. A detailed techno-economic analysis was made of the CAR process for supplying the oxygen in oxy-fuel combustion retrofit option using AEP's 450

  15. PHASE STRUCTURE AND THERMAL BEHAVIOR OF LIQUID CRYSTALLINE MULTI-BLOCK COPOLYMERS,POLY[1,6-BIS(4-OXYBENZOYL-OXY)HEXANE TEREPHTHALATE]-b-BISPHENOL A POLYCARBONATE

    Hui-qing Zhang; Xiong-yan Zhao; De-shan Liu; Qi-xiang Zhou

    1999-01-01

    Liquid crystalline multi-block copolymers poly[1,6-bis(4-oxybenzoyl-oxy)hexane terephthalate]-b-bisphenol A polycarbonate (PHTH-6-b-PC) with different segments of polycarbonate (PC) and thermotropic polyester PHTH-6 were synthesized in tetrachloroethane at 144~146℃. The influence of segment length on the resulting phase structure and thermal behavior of block copolymers was also discussed. It is demonstrated by TEM and DMA that the resulting block copolymers show a considerable microphase separation. The degree of phase separation and the thermal behavior of the block copolymers are strongly dependent on the molecular weight of the segments incorporated.

  16. Influência do molibdênio em propriedades do metal de solda na soldagem molhada com eletrodos óxi-rutílicos Influence of molybdenum in metal weld properties in welding wet with oxy-rutillic electrodes

    Luciana Ferreira Silva; Valter Rocha dos Santos; Sidnei Paciornik; Fernando Assunção Rizzo; Mauricio Jesus Monteiro; Alexandre Q. Bracarense; Ezequiel C. Pessoa; Leonardo A. Vieira; Marinho, R. R.

    2013-01-01

    A técnica de soldagem subaquática molhada com eletrodos revestidos apresenta um crescente potencial de aplicação para reparos submarinos em elementos estruturais de unidades flutuantes de produção de petróleo (profundidade até 20 m). Porém, ela apresenta problemas tais como o maior risco de fissuração a frio e de formação acentuada de porosidade. O presente trabalho tem como objetivo melhorar a resistência mecânica do metal de solda de um eletrodo experimental do tipo oxi-rutílico. Foram estu...

  17. Crystal structure of ethyl 4-(2-meth­oxy­phen­yl)-6-methyl-2-sulfanyl­idene-1,2,3,4-tetra­hydro­pyrimidine-5-carboxyl­ate

    Shaaban K. Mohamed; Mague, Joel T.; Akkurt, Mehmet; Khodairy, Ahmed; Eman A. Ahmed

    2015-01-01

    In the title compound, C15H18N2O3S, the hydro­pyrimidine ring adopts a sofa conformation with the methine C atom as the flap. The benzene ring is almost perpendicular to the mean plane of the hydro­pyrimidine ring, making a dihedral angle of 85.51 (8)°, and the meth­oxy O atom lies over the centre of the pyrimidine ring. In the crystal, weak N—H⋯S inter­actions form a zigzag chain running along the b-axis direction.

  18. Fe-Al Weld Overlay and High Velocity Oxy-Fuel Thermal Spray Coatings for Corrosion Protection of Waterwalls in Fossil Fired Plants with Low NOx Burners

    Regina, J.R.

    2002-02-08

    Iron-aluminum-chromium coatings were investigated to determine the best candidates for coatings of boiler tubes in Low NOx fossil fueled power plants. Ten iron-aluminum-chromium weld claddings with aluminum concentrations up to 10wt% were tested in a variety of environments to evaluate their high temperature corrosion resistance. The weld overlay claddings also contained titanium additions to investigate any beneficial effects from these ternary and quaternary alloying additions. Several High-Velocity Oxy-Fuel (HVOF) thermal spray coatings with higher aluminum concentrations were investigated as well. Gaseous corrosion testing revealed that at least 10wt%Al is required for protection in the range of environments examined. Chromium additions were beneficial in all of the environments, but additions of titanium were beneficial only in sulfur rich atmospheres. Similar results were observed when weld claddings were in contact with corrosive slag while simultaneously, exposed to the corrosive environments. An aluminum concentration of 10wt% was required to prevent large amounts of corrosion to take place. Again chromium additions were beneficial with the greatest corrosion protection occurring for welds containing both 10wt%Al and 5wt%Cr. The exposed thermal spray coatings showed either significant cracking within the coating, considerable thickness loss, or corrosion products at the coating substrate interface. Therefore, the thermal spray coatings provided the substrate very little protection. Overall, it was concluded that of the coatings studied weld overlay coatings provide superior protection in these Low NOx environments; specifically, the ternary weld composition of 10wt%Al and 5wt%Cr provided the best corrosion protection in all of the environments tested.

  19. Effect of solvent environment on the Photophysics of a newly synthesized bioactive 7-oxy(5-selenocyanato-pentyl)-2H-1-benzopyran-2-one

    The synthesis and solvatochromic behavior of the compound, 7-oxy(5-selenocyanato-pentyl)-2H-1-benzopyran-2-one (PCM), a pervasive, bioactive coumarin derivative, which is expected to possess antioxidative properties and other important therapeutic activities of significant potency with low systematic toxicity, have been reported employing steady state and time resolved fluorescence techniques. Spectroscopic studies reveal that the solvatochromic behavior of the probe depends not only on the polarity of the medium but also on the hydrogen bonding properties of the solvents. Specific hydrogen bonding interaction of PCM in polar solvents modulated the order of the two close-lying lowest singlet states. The photophysical response of PCM in different solvents has been explained considering solute-solvent interactions. To corroborate these results, we performed the ground-state geometry, lowest energy transition and the UV–vis spectrum of PCM using the density functional theory (DFT) and the time-dependent density functional theory (TD–DFT) at B3LYP/6-31G⁎ level. We found excellent correlation between the predicted and experimental spectral data, providing a useful tool in the design of new fluorogenic probes having potential therapeutic activity. - Highlights: ► Synthesis and photophysical behavior of the bioactive PCM. ► The order of the two close-lying lowest singlet states is modulated by H-bonding interaction in polar solvents. ► In non-polar solvent non-radiative path favor due to mixing of n,π⁎ and π,π⁎ singlet states. ► Quantum chemical calculation has been employed to corroborate with experimental finding.

  20. Dimethyl and diethyl esters of 5,6-bis-(pyridin-2-yl)pyrazine-2,3-di-carb-oxy-lic acid: a comparison.

    Alfonso, Montserrat; Stoeckli-Evans, Helen

    2016-02-01

    In dimethyl 5,6-bis-(pyridin-2-yl)pyrazine-2,3-di-carboxyl-ate, C18H14N4O4, (I), and diethyl 5,6-bis-(pyridin-2-yl)pyrazine-2,3-di-carboxyl-ate, C20H18N4O4, (II), the dimethyl and diethyl esters of 5,6-bis-(pyridin-2-yl)pyrazine-2,3-di-carb-oxy-lic acid, the orientation of the two pyridine rings differ. In (I), pyridine ring B is inclined to pyrazine ring A by 44.8 (2)° and the pyridine and pyrazine N atoms are trans to one another, while pyridine ring C is inclined to the pyrazine ring by 50.3 (2)°, with the pyridine and pyrazine N atoms cis to one another. In compound (II), the diethyl ester, which possesses twofold rotation symmetry, the pyridine ring is inclined to the pyrazine ring by 40.7 (1)°, with the pyridine and pyrazine N atoms trans to one another. In the crystal of (I), mol-ecules are linked by C-H⋯N hydrogen bonds, forming chains along [001]. The chains are linked by C-H⋯π inter-actions, forming a three-dimensional structure. In the crystal of (II), mol-ecules are linked via C-H⋯O hydrogen bonds, forming a three-dimensional framework. There are C-H⋯π inter-actions present within the framework. PMID:26958396

  1. Contribution to the study of sorption mechanisms at solid-liquid interfaces: application to the cases of apatites and oxy-hydroxides

    Sorption-desorption phenomena play an important role in the transport of toxic and radioactive elements in surface and underground water in contact with solid matter. Selenium, which is one of the long-lived radionuclides present in radioactive waste, is characterized by several oxidation states and by anionic species in aqueous solutions. In order to predict its transport, we need a good knowledge of its sorption processes. We have studied the sorption of Se(IV) and Se(VI) on two types of solids present in natural media or which have been proposed as additives to active barriers: hydroxy-apatites, fluoro-apatite and iron oxi-hydroxides (goethite and hematite). Sorption mechanisms have been studied through an approach including several different and complementary methods: titrimetry, zeta-metry, scanning and transmission electron microscopy, infrared spectroscopy, X-ray diffraction, X-ray photo electron spectroscopy, etc... Results showed that Se(VI) is much less sorbed than Se(VI) on both types of solids. For Se(IV) the sorption mechanisms are different for iron oxides and apatites. On oxides, sorption increases when pH decreases. It can be interpreted by a surface complexation model, essentially through an inner sphere complex (monodentate or bidentate). Modelling of Se sorption curves was performed after the determination of acido-basic properties of oxides. However, the determination of the intrinsic properties of oxides is disturbed by several parameters identified as impurities, evolution of the solid in solution, kinetic and solubility of the solid. For apatites, selenium sorption proceeds by exchange with superficial groups, with a maximum of fixation at approximately pH 8. Thanks to XPS measurements and the elaboration of a mathematical model, we could determine the depth of penetration of both selenium and cadmium on apatites. (author)

  2. High-Temperature Erosion-Corrosion Performance of High-Velocity Oxy-Fuel Sprayed Ni-20 Cr Coating in Actual Boiler Environment

    Kaushal, G.; Singh, H.; Prakash, S.

    2011-07-01

    The high-velocity oxy-fuel (HVOF) spray technique was used to deposit Ni-20Cr coating on a commonly used boiler steel ASTM A213 347H. The specimens with and without coating were exposed to the super heater zone of a thermal power plant boiler at a temperature of 973 K (700 °C) under cyclic conditions to ascertain their erosion-corrosion (E-C) behavior. High-temperature oxidation behavior of the specimens was also evaluated under cyclic thermal loading conditions at an elevated temperature of 1173 K (900 °C). Mass change data and thickness loss were measured to formulate the kinetics of E-C/oxidation for the specimens. The exposed specimens were characterized by X-ray diffraction (XRD) and field emission-scanning electron microscopy/energy dispersive spectroscopy (FE-SEM/EDS). The uncoated steel suffered higher E-C in comparison with its coated counterpart in terms of mass loss as well as thickness loss. It was observed that overall mass loss was reduced by 31 pct and thickness loss by 44 pct after the application of the coating. The possible formation of Cr2O3 phase in the coated substrate may be suggested to contribute to better E-C behavior. During air oxidation exposures, the coating was found to be intact with only marginal spallation of its oxide scales, which is an indicator of good adhesion between the coating and substrate steel. The air oxidation mass change data indicated that the coating enhanced the oxidation resistance of the steel by 85 pct.

  3. Experimental and numerical study of oxygen separation and oxy-combustion characteristics inside a button-cell LNO-ITM reactor

    A combined experimental and numerical study is performed on a button-cell LNO-ITM reactor. A semi-empirical model for oxygen permeation is considered, ABn model, and the values of the empirical constants are calculated based on the fitting of the available experimental data in the literature. A validation study for the present model is performed using the present experimental data. A detailed numerical study is presented on an LNO-ITM button-cell reactor under oxy-fuel combustion conditions. CH4 is used as the working fuel forming a mixture with CO2 at the permeate side inlet. The model results showed reasonable agreements under different operating conditions. The effect of reactivity in the permeate side of the membrane on oxygen permeation flux is considered. It is found that the oxygen permeation flux is increased by about 50% for the case of reacting flow as compared to the case of non-reacting flow. Distinct behavior of oxygen permeation flux values through the present button-cell ITM reactor is encountered while varying the operating conditions as compared to other reactors in the literature. This may be attributed to the complicated design of the flow path close to the membrane surface which maximizes the effects of flow momentum on the oxygen flux. - Highlights: • Experimental study on a button-cell LNO-ITM reactor. • A detailed numerical study is performed under oxyfuel combustion conditions. • A semi-empirical model is applied after fitting with the available LNO membrane data. • Different reactor geometries were considered for maximum combustion efficiency. • Flow rates are optimized for maximum oxygen flux and power generation

  4. Concentrations and origins of nitro-polycyclic aromatic hydrocarbons and oxy-polycyclic aromatic hydrocarbons in ambient air in urban and rural areas in northern China

    Twelve nitro-PAHs (nPAHs) and four oxy-PAHs (oPAHs) were measured in air samples for 12 months at 18 sites in urban settings, rural villages, or rural fields in northern China. The nPAH concentrations were higher in urban areas (1.3 ± 1.3 ng/m3), and nPAH/parent PAH ratios were higher (suggesting important contributions from motor vehicles and secondary formation) in urban sites than in rural villages. oPAHs are primarily emitted from solid fuel combustion and motor vehicles, and similar oPAH concentrations were found in urban areas (23 ± 20 ng/m3) and rural villages (29 ± 24 ng/m3). The high numbers of motor vehicles in Beijing and intensive industrial activity in Taiyuan and Dezhou caused higher nPAH concentrations. No spatial trend in oPAH concentrations was found in the rural villages, because similar oPAH mixtures are emitted from solild fuel combustion. The nPAH and oPAH concentrations were higher in the winter, and correlated with residential energy consumption and precipitation. - Highlights: • nPAH levels in cities were higher than in rural area due to vehicle emission. • oPAH concentrations were similar between urban and rural villages. • Concentrations of nPAHs and oPAHs in winter were higher than those in summer. • Strong secondary formation of nPAH occurs in the urban area in summer. - The nPAH concentrations were significantly higher in the urban area than in the rural villages, while oPAH concentrations in rural villages were similar to those in urban area

  5. Ignition and Combustion of Pulverized Coal and Biomass under Different Oxy-fuel O2/N2 and O2/CO2 Environments

    Khatami Firoozabadi, Seyed Reza

    This work studied the ignition and combustion of burning pulverized coals and biomasses particles under either conventional combustion in air or oxy-fuel combustion conditions. Oxy-fuel combustion is a 'clean-coal' process that takes place in O2/CO2 environments, which are achieved by removing nitrogen from the intake gases and recirculating large amounts of flue gases to the boiler. Removal of nitrogen from the combustion gases generates a high CO2-content, sequestration-ready gas at the boiler effluent. Flue gas recirculation moderates the high temperatures caused by the elevated oxygen partial pressure in the boiler. In this study, combustion of the fuels took place in a laboratory laminar-flow drop-tube furnace (DTF), electrically-heated to 1400 K, in environments containing various mole fractions of oxygen in either nitrogen or carbon-dioxide background gases. The experiments were conducted at two different gas conditions inside the furnace: (a) quiescent gas condition (i.e., no flow or inactive flow) and, (b) an active gas flow condition in both the injector and furnace. Eight coals from different ranks (anthracite, semi-snthracite, three bituminous, subbituminous and two lignites) and four biomasses from different sources were utilized in this work to study the ignition and combustion characteristics of solid fuels in O2/N2 or O2/CO2 environments. The main objective is to study the effect of replacing background N2 with CO2, increasing O2 mole fraction and fuel type and rank on a number of qualitative and quantitative parameters such as ignition/combustion mode, ignition temperature, ignition delay time, combustion temperatures, burnout times and envelope flame soot volume fractions. Regarding ignition, in the quiescent gas condition, bituminous and sub-bituminous coal particles experienced homogeneous ignition in both O2/N 2 and O2/CO2 atmospheres, while in the active gas flow condition, heterogeneous ignition was evident in O2/CO 2. Anthracite, semi

  6. Rat Endovascular Perforation Model

    Sehba, Fatima A.

    2014-01-01

    Experimental animal models of aneurysmal subarachnoid hemorrhage (SAH) have provided a wealth of information on the mechanisms of brain injury. The Rat endovascular perforation model (EVP) replicates the early pathophysiology of SAH and hence is frequently used to study early brain injury following SAH.

  7. The academic rat race

    Landes, Xavier; Andersen, Martin Marchman; Nielsen, Morten Ebbe Juul

    2012-01-01

    increased pressure to produce articles (in peer-reviewed journals) has created an unbalanced emphasis on the research criterion at the expense of the latter two. More fatally, this pressure has turned academia into a rat race, leading to a deep change in the fundamental structure of academic behaviour, and...

  8. Preparation, crystal structure and luminescent properties of the (6,3) type network supramolecular lanthanide picrate complexes with 2,2'-[(1,2-naphthalene)bis(oxy)]bis[N-(phenylmethyl)]acetamide

    Solid complexes of lanthanide picrates with a new podand-type ligand, 2,2'-[(1,2-naphthalene)bis(oxy)]bis[N-(phenylmethyl)]acetamide (L) have been prepared and characterized by elemental analysis, conductivity measurements, IR and electronic spectroscopies. The crystal and molecular structures of the coordination polymer {[Eu2L3(Pic)6].(CHCl3)3.(H2O)0.5}n have been determined by single-crystal X-ray diffraction, and the structure displays a two-dimensional honeycomb-like framework in the ab plane, which can be regarded as a (6,3) topological network with europium atoms acting as 'three-connected' centers. Furthermore, the coordination layers are linked by the intermolecular hydrogen bonds to form a three-dimensional (3-D) netlike supermolecule. Under excitation, Eu complex exhibited characteristic emissions. The lowest triplet state energy level of the ligand indicates that the triplet state energy level of the ligand matches better to the resonance level of Eu(III) than Tb(III) ion. - Graphical abstract: The (6,3) type network supramolecular luminescent lanthanide picrate complexes {Ln2L3(Pic)6}n (L=2,2'-[(1,2-naphthalene)bis(oxy)]bis[N-(phenylmethyl)]acetamide) displaying a two-dimensional honeycomb-like framework have been designed and prepared.

  9. The effects of the pressure and the oxygen content of the sputtering gas on the structure and the properties of zinc oxy-nitride thin films deposited by reactive sputtering of zinc

    Zinc nitride and oxy-nitride thin films were prepared by reactive magnetron rf sputtering of zinc in either nitrogen–argon or nitrogen–argon–oxygen ambient. The effects of varying the total sputtering pressure and the oxygen fraction in the total sputtering gas mixture on the microstructure, electrical and optical properties were investigated. With increasing the sputtering pressure, the dominant phase comprising the film material changes from the crystalline zinc nitride phase to crystalline zinc oxide. The characteristic pressure, at which this change in the dominant phase is observed, decreases with the increase of the oxygen fraction in the total sputtering gas mixture. The increase of the oxygen content in the films (from 5 at.% to a maximum of 40 at.%) and the downward shift in the optical absorption edge (from 920 to 400 nm), combined with the x-ray diffraction data, support these observations, indicating the controllable fabrication of an oxy-nitride film material. Correlations between the films’ fabrication conditions, including post-deposition annealing, their structure and composition, and their electrical properties are examined as well. (paper)

  10. Crystal structure of a nucleoside model for the inter­strand cross-link formed by the reaction of 2′-de­oxy­guanosine and an abasic site in duplex DNA

    Catalano, Michael J.; Ruddraraju, Kasi Viswanatharaju; Barnes, Charles L.; Gates, Kent S.

    2016-01-01

    The title compound, 9-[(2R,4S,5R)-4-hy­droxy-5-(hy­droxy­meth­yl)tetra­hydro­furan-2-yl]-2-{[(2R,4S,5R)-4-meth­oxy-5-(meth­oxy­meth­yl)tetra­hydro­furan-2-yl]amino}-1H-purin-6(9H)-one, C17H25N5O7, crystallizes with two independent mol­ecules (A and B) in the asymmetric unit. In the crystal, the guanosine moieties of mol­ecules A and B are linked by N—H⋯N and O—H⋯N hydrogen-bonding inter­actions, forming ribbons which are stacked to form columns along [100]. These columns are then linked by O—H⋯O hydrogen bonds between the ribose moieties and numerous C—H⋯O inter­actions to complete the three-dimensional structure. PMID:27308004

  11. Combustion synthesis and optical properties of Oxy-borate phosphors YCa4O(BO3)3:RE3+ (RE = Eu3+, Tb3+) under UV, VUV excitation

    Graphical abstract: VUV Photoluminescence of YCa4O(BO3)3: Eu3+ and YCa4O(BO3)3: Tb3+ for PDPs applications. Highlights: • Inorganic Oxy-borate phosphors YCa4O(BO3)3:Eu3+,Tb3+ was synthesized by novel solution combustion synthesis. • This single host produces efficient and intense Red and Green color for display applications. • Good agreement with CIE co-ordinates as prescribes by NTCL, for flat panel, PDP display color. • Synthesized materials were characterized using powder XRD, FE-SEM, UV and VUV Spectophotometer. -- Abstract: The inorganic Oxy-borate host phosphors YCa4O(BO3)3:RE3+ (RE = Eu3+,Tb3+) were synthesized by a novel solution combustion technique. The synthesis is based on the exothermic reaction between the fuel (Urea) and Oxidizer (Ammonium nitrate). The heat generated in reaction is use for auto combustion of precursors. The structures of the prepared samples were confirmed by powder XRD technique. The photoluminescence properties of the powder samples were investigated under UV and VUV excitation; “The phosphor YCa4O(BO3)3:Eu3+and YCa4O(BO3)3:Tb3+ shows strong absorption in UV and VUV region and exhibits intense red and green emission upon excited by 254 nm UV and 147 nm VUV radiation”

  12. Crystal structure of (E)-13-{4-[(Z)-2-cyano-2-(3,4,5-tri­meth­oxy­phen­yl)ethen­yl]phen­yl}parthenolide methanol hemisolvate

    Penthala, Narsimha Reddy; Bommagani, Shobanbabu; Janganati, Venumadhav; Parkin, Sean; Crooks, Peter A.

    2014-01-01

    The title compound, C33H35NO6 [systematic name: (Z)-3-(4-{(E)-[(E)-1a,5-dimethyl-9-oxo-2,3,7,7a-tetra­hydro­oxireno[2′,3′:9,10]cyclo­deca­[1,2-b]furan-8(1aH,6H,9H,10aH,10bH)-yl­idene]meth­yl}phen­yl)-2-(3,4,5-tri­meth­oxy­phen­yl)acrylo­ni­trile methanol hemisolvate], C33H35NO6·0.5CH3OH, was prepared by the reaction of (Z)-3-(4-iodo­phen­yl)-2-(3,4,5-tri­meth­oxy­phen­yl)acrylo­nitrile with parthenolide [systematic name: (E)-1a,5-dimethyl-8-methyl­ene-2,3,6,7,7a,8,10a,10b-octa­hy­dro­oxireno[...

  13. Integration of in-situ CO2-oxy coal gasification with advanced power generating systems performing in a chemical looping approach of clean combustion

    Highlights: • Integration of CO2/O2 based UCG, CLC and CCS for clean coal utilization. • Incorporation of CLC system reduces the ASU load of the power plant. • Use of CO enriched UCG gas in Ni based CLC reduces the difficulty of heat balance. • Coupling of the proposed UCG with IGCC and IGST for the efficient power generation. • Demonstration of reduced CCS energy penalty in the advanced coupled system. - Abstract: Underground coal gasification (UCG) is a clean coal technology to utilize deep coal resources effectively. In-situ CO2-oxy coal gasification may eliminate the operational difficulty of the steam gasification process and utilize CO2 (greenhouse gas) effectively. Furthermore, it is necessary to convert the clean gasified energy from the UCG into clean combustion energy for an end-use. In order to achieve efficient clean power production, the present work investigates the thermodynamic feasibility of integration of CO2 based UCG with power generating systems operating in a chemical looping combustion (CLC) of product gas. The use of CO enriched syngas from O2/CO2 based UCG reduces the difficulty of the heat balance between a fuel reactor and an air reactor in a nickel oxygen-carrier based CLC system. Thermodynamic analyses have been made for various routes of power generation systems such as subcritical, supercritical and ultra-supercritical boiler based steam turbines and gas turbines for the UCG integrated system. It is shown, based on mass and energy balance analysis, that the integration of CO2 based UCG with the CLC system reduces the energy penalty of carbon capture and storage (CCS) significantly. A net thermal efficiency of 29.42% is estimated for the CCS incorporated system, which operates in a subcritical condition based steam turbine power plant. Furthermore, it is found that the efficiency of the proposed steam turbine system increases to 35.40% for an ultra-supercritical operating condition. The effect of operating temperature of the

  14. EPR and ENDOR characterization of the reactive intermediates in the generation of NO by cryoreduced oxy-nitric oxide synthase from Geobacillus stearothermophilus.

    Davydov, Roman; Sudhamsu, Jawahar; Lees, Nicholas S; Crane, Brian R; Hoffman, Brian M

    2009-10-14

    Cryoreduction EPR/ENDOR/step-annealing measurements with substrate complexes of oxy-gsNOS (3; gsNOS is nitric oxide synthase from Geobacillus stearothermophilus) confirm that Compound I (6) is the reactive heme species that carries out the gsNOS-catalyzed (Stage I) oxidation of L-arginine to N-hydroxy-L-arginine (NOHA), whereas the active species in the (Stage II) oxidation of NOHA to citrulline and HNO/NO(-) is the hydroperoxy-ferric form (5). When 3 is reduced by tetrahydrobiopterin (BH4), instead of an externally supplied electron, the resulting BH4(+) radical oxidizes HNO/NO(-) to NO. In this report, radiolytic one-electron reduction of 3 and its complexes with Arg, Me-Arg, and NO(2)Arg was shown by EPR and (1)H and (14,15)N ENDOR spectroscopies to generate 5; in contrast, during cryoreduction of 3/NOHA, the peroxo-ferric-gsNOS intermediate (4/NOHA) was trapped. During annealing at 145 K, ENDOR shows that 5/Arg and 5/Me-Arg (but not 5/NO(2)Arg) generate a Stage I primary product species in which the OH group of the hydroxylated substrate is coordinated to Fe(III), characteristic of 6 as the active heme center. Analysis shows that hydroxylation of Arg and Me-Arg is quantitative. Annealing of 4/NOHA at 160 K converts it first to 5/NOHA and then to the Stage II primary enzymatic product. The latter contains Fe(III) coordinated by water, characteristic of 5 as the active heme center. It further contains quantitative amounts of citrulline and HNO/NO(-); the latter reacts with the ferriheme to form the NO-ferroheme upon further annealing. Stage I delivery of the first proton of catalysis to the (unobserved) 4 formed by cryoreduction of 3 involves a bound water that may convey a proton from L-Arg, while the second proton likely derives from the carboxyl side chain of Glu 248 or the heme carboxylates; the process also involves proton delivery by water(s). In the Stage II oxidation of NOHA, the proton that converts 4/NOHA to 5/NOHA likely is derived from NOHA itself, a

  15. Tuning the properties of visible-light-responsive tantalum (oxy)nitride photocatalysts by non-stoichiometric compositions: A first-principles viewpoint

    Harb, Moussab

    2014-01-01

    Finding an ideal photocatalyst for achieving efficient overall water splitting still remains a great challenge. By applying accurate first-principles quantum calculations based on DFT with the screened non-local hybrid HSE06 functional, we bring rational insights at the atomic level into the influence of non-stoichiometric compositions on essential properties of tantalum (oxy)nitride compounds as visible-light-responsive photocatalysts for water splitting. Indeed, recent experiments show that such non-stoichiometry is inherent to the nitridation methods of tantalum oxide with unavoidable oxygen impurities. We considered here O-enriched Ta3N5 and N-enriched TaON materials. Although their structural parameters are found to be very similar to those of pure compounds and in good agreement with available experimental studies, their photocatalytic features for visible-light-driven overall water splitting reactions show different behaviors. Further partial nitration of TaON leads to a narrowed band gap, but partially oxidizing Ta3N5 causes only subtle changes in the gap. The main influence, however, is on the band edge positions relative to water redox potentials. The pure Ta3N5 is predicted to be a good candidate only for H+ reduction and H2 evolution, while the pure TaON is predicted to be a good candidate for water oxidation and O2 evolution. Non-stoichiometry has here a positive influence, since partially oxidized tantalum nitride, Ta(3-x)N(5-5x)O5x (for x ≥ 0.16) i.e. with a composition in between TaON and Ta3N5, reveals suitable band edge positions that correctly bracket the water redox potentials for visible-light-driven overall water splitting reactions. Among the various explored Ta(3-x)N(5-5x)O5x structures, a strong stabilization is obtained for the configuration displaying a strong interaction between the O-impurities and the created Ta-vacancies. In the lowest-energy structure, each created Ta-vacancy is surrounded by five O-impurity species substituting

  16. DEGRADATION OF OXO-BIODEGRADABLE AND USUAL PLASTIC PACKAGING = DEGRADAÇÃO DE EMBALAGENS PLÁSTICAS OXI-BIODEGRADÁVEIS E COMUNS

    Caio da Silva Miranda

    2015-11-01

    Full Text Available The mostly packaging Urban Solid Waste are bought or acquired in commercial establishments. This study was possible to analyze the degradation of packaging urban solid waste, checking which packages used by consumers cause for less impact on the environment. The experimental conditions adopted in this present study are due to the variation of temperature, time, amount of leachate and/ or rainwater. Therefore, with the experiments it can be seen that variation of nutrients matches the variation of microorganism in the filtrate of rainwater and leachate. The samples immersed in rainwater and leachate obtained opposite results among themselves. The samples have degraded more at the high temperatures. In a short exposure time have been shown to hardly relevant to the degradation. In general the oxo-biodegradable packaging get showed similar results with the usual packaging. = A maioria das embalagens plásticas é sacola comprada ou recebida gratuitamente de estabelecimentos comerciais. No presente trabalho foi possível analisar a degradação de embalagens plásticas oxi-biodegradáveis e as comuns, verificando quais delas utilizadas pelos consumidores causam menos impacto ao meio ambiente. As condições experimentais adotadas no presente trabalho foram em função da variação de temperatura, tempo, na presença de chorume e de água de chuva. Com a realização dos experimentos pode-se observar que uma variação de nutrientes condisse com a variação de micro-organismos nos filtrados de água da chuva e do chorume. As amostras imersas em água da chuva e no chorume obtiveram efeitos inversos entre si. As amostras degradaram mais em altas temperaturas. Em pequeno período de exposição, o tempo se mostrou pouco relevante para a degradação. De uma forma geral, as embalagens oxibiodegradáveis apresentaram resultados parecidos com as embalagens comuns.

  17. Source memory in the rat

    Crystal, Jonathon D.; Alford, Wesley T.; Zhou, Wenyi; Hohmann, Andrea G.

    2013-01-01

    Source memory is a representation of the origin (source) of information. When source information is bound together, it makes a memory episodic, allowing us to differentiate one event from another [1, 2]. Here we asked if rats remember the source of encoded information. Rats foraged for distinctive flavors of food that replenished (or failed to replenish) at its recently encountered location according to a source-information rule. To predict replenishment, rats needed to remember where they ha...

  18. The Year of the Rat

    2008-01-01

    Do you know what your Chinese sign of the zodiac is? According to the Chinese lunar calendar,every year corre- sponds to one of twelve animals(rat,ox,tiger,rabbit,dragon, snake,horse,sheep,monkey,rooster,dog and pig)and these animals are used to identify years. After the Lunar New Year in 2008 we enter the rat year. All those born in 1996,1984,1972.1960,1948,1936 or 1924, also have a rat as their sign.

  19. Postconditioning in rats and mice

    2006-01-01

    Objective . For subsequent studies on the molecular mechanisms of postconditioning, we aimed to identify a robust postconditioning protocol in rat and mouse heart. Design. Isolated rat hearts were subjected to different postconditioning protocols (study 1 and 2). The protection was compared to preconditioning. Rats (study 3) in vivo in two different laboratories were postconditioned. Isolated mouse hearts (study 4) and mice in vivo (study 5) were postconditioned. Results. Postconditioning did...

  20. Laughing rats are optimistic.

    Rygula, Rafal; Pluta, Helena; Popik, Piotr

    2012-01-01

    Emotions can bias human decisions- for example depressed or anxious people tend to make pessimistic judgements while those in positive affective states are often more optimistic. Several studies have reported that affect contingent judgement biases can also be produced in animals. The animals, however, cannot self-report; therefore, the valence of their emotions, to date, could only be assumed. Here we present the results of an experiment where the affect-contingent judgement bias has been produced by objectively measured positive emotions. We trained rats in operant Skinner boxes to press one lever in response to one tone to receive a food reward and to press another lever in response to a different tone to avoid punishment by electric foot shock. After attaining a stable level of discrimination performance, the animals were subjected to either handling or playful, experimenter-administered manual stimulation - tickling. This procedure has been confirmed to induce a positive affective state in rats, and the 50-kHz ultrasonic vocalisations (rat laughter) emitted by animals in response to tickling have been postulated to index positive emotions akin to human joy. During the tickling and handling sessions, the numbers of emitted high-frequency 50-kHz calls were scored. Immediately after tickling or handling, the animals were tested for their responses to a tone of intermediate frequency, and the pattern of their responses to this ambiguous cue was taken as an indicator of the animals' optimism. Our findings indicate that tickling induced positive emotions which are directly indexed in rats by laughter, can make animals more optimistic. We demonstrate for the first time a link between the directly measured positive affective state and decision making under uncertainty in an animal model. We also introduce innovative tandem-approach for studying emotional-cognitive interplay in animals, which may be of great value for understanding the emotional-cognitive changes