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Sample records for phosphoric acid activation

  1. Phosphoric acid

    Integrated Risk Information System (IRIS)

    Phosphoric acid ; CASRN 7664 - 38 - 2 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic

  2. Porous texture of activated carbons prepared by phosphoric acid activation of woods

    NASA Astrophysics Data System (ADS)

    Díaz-Díez, M. A.; Gómez-Serrano, V.; Fernández González, C.; Cuerda-Correa, E. M.; Macías-García, A.

    2004-11-01

    Activated carbons (ACs) have been prepared using chestnut, cedar and walnut wood shavings from furniture industries located in the Comunidad Autónoma de Extremadura (SW Spain). Phosphoric acid (H3PO4) at different concentrations (i.e. 36 and 85 wt.%) has been used as activating agent. ACs have been characterized from the results obtained by N2 adsorption at 77 K. Moreover, the fractal dimension (D) has been calculated in order to determine the AC surface roughness degree. Optimal textural properties of ACs have been obtained by chemical activation with H3PO4 36 wt.%. This is corroborated by the slightly lower values of D for samples treated with H3PO4 85 wt.%.

  3. Porous structure and surface chemistry of phosphoric acid activated carbon from corncob

    NASA Astrophysics Data System (ADS)

    Sych, N. V.; Trofymenko, S. I.; Poddubnaya, O. I.; Tsyba, M. M.; Sapsay, V. I.; Klymchuk, D. O.; Puziy, A. M.

    2012-11-01

    Active carbons have been prepared from corncob using chemical activation with phosphoric acid at 400 °C using varied ratio of impregnation (RI). Porous structure of carbons was characterized by nitrogen adsorption and scanning electron microscopy. Surface chemistry was studied by IR and potentiometric titration method. It has been shown that porosity development was peaked at RI = 1.0 (SBET = 2081 m2/g, Vtot = 1.1 cm3/g), while maximum amount of acid surface groups was observed at RI = 1.25. Acid surface groups of phosphoric acid activated carbons from corncob includes phosphate and strongly acidic carboxylic (pK = 2.0-2.6), weakly acidic carboxylic (pK = 4.7-5.0), enol/lactone (pK = 6.7-7.4; 8.8-9.4) and phenol (pK = 10.1-10.7). Corncob derived carbons showed high adsorption capacity to copper, especially at low pH. Maximum adsorption of methylene blue and iodine was observed for carbon with most developed porosity (RI = 1.0).

  4. Development of mesoporosity during phosphoric acid activation of wood in steam atmosphere.

    PubMed

    Klijanienko, Aleksandra; Lorenc-Grabowska, Ewa; Gryglewicz, Grazyna

    2008-10-01

    Oak and birch were used as precursors to produce the activated carbons (ACs) with well-developed mesoporosity by phosphoric acid-promoted activation in a steam atmosphere. The effect of experimental variables such as the amount of activating agent, the soaking time and the type of wood on the development of porous structure upon heating at 480 degrees C was investigated. The materials were characterized by N2 adsorption at 77K, mercury porosimetry and elemental analysis. It was demonstrated that increasing impregnation ratio favors the development of micropores and small mesopores of 2-5nm, whereas the soaking time promotes the creation of large mesopores, between 10 and 50nm. Compared to birch, the oak activation using phosphoric acid in the same conditions gives ACs with lower mesopore volume and higher contribution of small mesopores that reflects the differences between both precursors in their biopolymer composition. The presence of steam in the H3PO4 activation process compared to nitrogen facilitates the development of mesoporosity to much higher extent for the birch than that of oak. The ACs prepared in this work show the BET surface area ranging from 800 to 2250m2g(-1), the total pore volume of 0.35-2.04cm3g(-1) with mesopore fraction between 0.06 and 0.68. PMID:18255286

  5. Stabilizing platinum in phosphoric acid fuel cells

    NASA Technical Reports Server (NTRS)

    Remick, R. J.

    1982-01-01

    Platinum sintering on phosphoric acid fuel cell cathodes is discussed. The cathode of the phosphoric acid fuel cell uses a high surface area platinum catalyst dispersed on a conductive carbon support to minimize both cathode polarization and fabrication costs. During operation, however, the active surface area of these electrodes decreases, which in turn leads to decreased cell performance. This loss of active surface area is a major factor in the degradation of fuel cell performance over time.

  6. Utilization of date stones for production of activated carbon using phosphoric acid

    SciTech Connect

    Haimour, N.M. . E-mail: nomanhaimour@hotmail.com; Emeish, S. . E-mail: s_emiesh@yahoo.com

    2006-07-01

    Date stone wastes have been utilized for production of activated carbon by chemical activation with phosphoric acid using a fluidized-bed reactor. The effects of the activation time, activation temperature, impregnation ratio, and particle size on the yield and the adsorptive capacity towards iodine were studied. The yield and the quality of the activated carbon prepared by using H{sub 3}PO{sub 4} were compared with that prepared from date stones using the same equipment, and under similar conditions by using ZnCl{sub 2} as an oxidizing agent. The maximum value of the iodine number of the activated carbon produced using H{sub 3}PO{sub 4} in this work was about 495 under the following conditions: impregnation ratio 0.4, activation time 60 min, activation temperature 800 deg. C, particle size 0.60 mm. The iodine number for the produced activated carbon was higher when phosphoric acid was used, compared to that when zinc chloride was used as impregnation reagent; however, the yield obtained when H{sub 3}PO{sub 4} was used was lower than the yield when ZnCl{sub 2} was used. The iodine number increases significantly with increasing the activation temperature. By increasing the impregnation ratio at the same temperature, the iodine number decreased sharply and an oscillation is noticed for all the cases but it was clearer at 800 deg. C. The average variation of the iodine number for the whole range of particle size used in this work is {+-}10%.

  7. Active and Passive Application of the Phosphoric Acid on the Bond Strength of Lithium Disilicate.

    PubMed

    Giraldo, Tatiana Cardona; Villada, Vanessa Roldan; Castillo, Mauricio Peña; Gomes, Osnara Maria Mongruel; Bittencourt, Bruna Fortes; Dominguez, John Alexis

    2016-01-01

    The objective of this study was to evaluate the effect of passive or active phosphoric acid (PA) application after hydrofluoric acid (HA) treatment on the microshear bond strength of lithium disilicate. Thirty ceramic discs were made with IPS Emax 2 (10 mm thick and 10 mm diameter). The specimens were divided into 3 groups, A: 9.6% HA application; AF: 9.6% HA application + cleaning with 37% PA in passive mode and AFF: 9.6% HA application + cleaning with 37% PA in active mode. For the microshear test, four tygons (0.9 mm diameter and 0.2 mm high) were filled with resin cement (RelyX Ultimate) and placed on the ceramic disks. After testing, the fracture modes were examined under scanning electron microscopy. Data were analyzed by one-way ANOVA and Tukey's post test (α=0.05). The bond strength values were significantly higher in Group AFF (11.0±2.5 MPa) compared with group A (8.1±2.6 MPa) (p<0.002). AF group was not statistically different (9.4±2.5 MPa) from Group A. It was concluded that the active application of 37% PA after 9.6% HA increases the microshear bond strength values between the resin cement and lithium disilicate ceramic.

  8. Micro-electro-mechanical systems phosphoric acid fuel cell

    DOEpatents

    Sopchak, David A.; Morse, Jeffrey D.; Upadhye, Ravindra S.; Kotovsky, Jack; Graff, Robert T.

    2010-08-17

    A phosphoric acid fuel cell system comprising a porous electrolyte support, a phosphoric acid electrolyte in the porous electrolyte support, a cathode electrode contacting the phosphoric acid electrolyte, and an anode electrode contacting the phosphoric acid electrolyte.

  9. Micro-electro-mechanical systems phosphoric acid fuel cell

    DOEpatents

    Sopchak, David A.; Morse, Jeffrey D.; Upadhye, Ravindra S.; Kotovsky, Jack; Graff, Robert T.

    2010-12-21

    A phosphoric acid fuel cell system comprising a porous electrolyte support, a phosphoric acid electrolyte in the porous electrolyte support, a cathode electrode contacting the phosphoric acid electrolyte, and an anode electrode contacting the phosphoric acid electrolyte.

  10. Removal of chromium(VI) from wastewater using phosphoric acid treated activated carbon

    NASA Astrophysics Data System (ADS)

    Suganthi, N.

    2013-06-01

    Activated carbon prepared by phosphoric acid treatment of tamarind nuts (seeds) was investigated for the removal of Cr(VI) from aqueous solutions. The characteristics of phosphorylated tamarind nut carbon (PTNC) were evaluated for porosity and surface area. The effect of contact time, pH, adsorbent dose and particle size variation were studied to evaluate the potential applicability of carbon for treating Cr(VI) containing wastewater. The adsorbent data were modeled by Langmiur and Freundlich classical adsorption isotherms. The kinetic studies showed that Cr(VI) adsorption on PTNC was in compliance with the pseudo-second-order kinetic model. Desorption studies indicated that ion-exchange mechanism was operating. The continuous adsorption was studied in glass columns of 2.5 cm diameter using electroplating wastewater to ascertain the practical applicability of PTNC in large scale. The mechanism of adsorption was found to be ion-exchange process and was supported by FTIR spectroscopy. The surface modification after adsorption was confirmed by SEM studies.

  11. 21 CFR 182.1073 - Phosphoric acid.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Phosphoric acid. 182.1073 Section 182.1073 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN....1073 Phosphoric acid. (a) Product. Phosphoric acid. (b) Conditions of use. This substance is...

  12. 21 CFR 582.1073 - Phosphoric acid.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Phosphoric acid. 582.1073 Section 582.1073 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1073 Phosphoric acid. (a) Product. Phosphoric acid. (b) Conditions of use. This substance...

  13. 21 CFR 582.1073 - Phosphoric acid.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Phosphoric acid. 582.1073 Section 582.1073 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1073 Phosphoric acid. (a) Product. Phosphoric acid. (b) Conditions of use. This substance...

  14. 21 CFR 582.1073 - Phosphoric acid.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Phosphoric acid. 582.1073 Section 582.1073 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1073 Phosphoric acid. (a) Product. Phosphoric acid. (b) Conditions of use. This substance...

  15. 21 CFR 582.1073 - Phosphoric acid.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Phosphoric acid. 582.1073 Section 582.1073 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1073 Phosphoric acid. (a) Product. Phosphoric acid. (b) Conditions of use. This substance...

  16. 21 CFR 182.1073 - Phosphoric acid.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Phosphoric acid. 182.1073 Section 182.1073 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... Substances § 182.1073 Phosphoric acid. (a) Product. Phosphoric acid. (b) Conditions of use. This substance...

  17. 21 CFR 182.1073 - Phosphoric acid.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Phosphoric acid. 182.1073 Section 182.1073 Food... GENERALLY RECOGNIZED AS SAFE Multiple Purpose GRAS Food Substances § 182.1073 Phosphoric acid. (a) Product. Phosphoric acid. (b) Conditions of use. This substance is generally recognized as safe when used...

  18. 21 CFR 582.1073 - Phosphoric acid.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Phosphoric acid. 582.1073 Section 582.1073 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1073 Phosphoric acid. (a) Product. Phosphoric acid. (b) Conditions of use. This substance...

  19. 21 CFR 182.1073 - Phosphoric acid.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Phosphoric acid. 182.1073 Section 182.1073 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... Substances § 182.1073 Phosphoric acid. (a) Product. Phosphoric acid. (b) Conditions of use. This substance...

  20. 21 CFR 182.1073 - Phosphoric acid.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Phosphoric acid. 182.1073 Section 182.1073 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... Substances § 182.1073 Phosphoric acid. (a) Product. Phosphoric acid. (b) Conditions of use. This substance...

  1. Adsorption properties of biomass-based activated carbon prepared with spent coffee grounds and pomelo skin by phosphoric acid activation

    NASA Astrophysics Data System (ADS)

    Ma, Xiaodong; Ouyang, Feng

    2013-03-01

    Activated carbon prepared from spent coffee grounds and pomelo skin by phosphoric acid activation had been employed as the adsorbent for ethylene and n-butane at room temperature. Prepared activated carbon was characterized by means of nitrogen adsorption-desorption, X-ray powder diffraction, scanning electron microscope and Fourier transform infrared spectroscope. It was confirmed that pore structure played an important role during the adsorption testes. Adsorption isotherms of ethylene and n-butane fitted well with Langmuir equation. The prepared samples owned better adsorption capacity for n-butane than commercial activated carbon. Isosteric heats of adsorptions at different coverage were calculated through Clausius-Clapeyron equation. Micropore filling effect was explained in a thermodynamic way.

  2. Effect of Phosphoric Acid Concentration on the Characteristics of Sugarcane Bagasse Activated Carbon

    NASA Astrophysics Data System (ADS)

    Adib, M. R. M.; Suraya, W. M. S. W.; Rafidah, H.; Amirza, A. R. M.; Attahirah, M. H. M. N.; Hani, M. S. N. Q.; Adnan, M. S.

    2016-07-01

    Impregnation method is one of the crucial steps involved in producing activated carbon using chemical activation process. Chemicals employed in this step is effective at decomposing the structure of material and forming micropores that helps in adsorption of contaminants. This paper explains thorough procedures that have been involved in producing sugarcane bagasse activated carbon (SBAC) by using 5%, 10%, 20%, 30% phosphoric acid (H3PO4) during the impregnation step. Concentration of H3PO4 used in the process of producing SBAC was optimized through several tests including bulk density, ash content, iodine adsorption and pore size diameter and the charactesristic of optimum SBAC produced has been compared with commercial activated carbon (CAC). Batch study has been carried out by using the SBAC produced from optimum condition to investigate the performance of SBAC in removal of turbidity and chemical oxygen demand (COD) from textile wastewater. From characteristic study, SBAC with 30% H3PO4 has shown the optimum value of bulk density, ash content, iodine adsorption and pore size diameter of 0.3023 g cm-3, 4.35%, 974.96 mg/g and 0.21-0.41 µm, respectively. These values are comparable to the characteristics of CAC. Experimental result from the batch study has been concluded that the SBAC has a promising potential in removing turbidity and COD of 75.5% and 66.3%, respectively which was a slightly lower than CAC which were able to remove 82.8% of turbidity and 70% of COD. As a conclusion, the SBAC is comparable with CAC in terms of their characteristics and the capability of removing contaminants from textile wastewater. Therefore, it has a commercial value to be used as an alternative of low-cost material in producing CAC.

  3. Inorganic polymers from laterite using activation with phosphoric acid and alkaline sodium silicate solution: Mechanical and microstructural properties

    SciTech Connect

    Lassinantti Gualtieri, Magdalena

    2015-01-15

    Geopolymers from laterite, an iron-rich soil available in developing countries, have great potential as building materials. In this work, laterite from Togo (Africa) was used to prepare geopolymers using both phosphoric acid and alkaline sodium silicate solution. Microstructural properties were investigated by scanning electron microscopy, X-ray powder diffraction and mercury porosimetry, whereas thermal properties were evaluated by thermal analyses. The local environment of iron was studied by X-ray Absorption Spectroscopy (XANES region). The mechanical properties were determined. Modulus of Rupture and Young's modulus fell in the ranges 3.3–4.5 MPa and 12–33 GPa, respectively, rendering the materials good candidates for construction purposes. Heating above 900 °C results in weight-gain, presumably due to iron redox reactions. X-ray Absorption Spectroscopy data evidence changes in the chemical and structural environments of iron following thermal treatment of geopolymers. These changes indicate interaction between the geopolymer structure and iron during heating, possibly leading to redox properties. -- Highlights: •Geopolymerization of laterite is promising for fabrication of building materials. •Both phosphoric acid and alkaline sodium silicate solution can be used for activation. •Thermally activated redox properties of the inorganic polymers were observed.

  4. Activity inhibition and its mitigation in high temperature proton exchange membrane fuel cells: The role of phosphoric acid, ammonium trifluoromethanesulfonate, and polyvinylidene difluoride

    NASA Astrophysics Data System (ADS)

    Holst-Olesen, Kaspar; Nesselberger, Markus; Perchthaler, Markus; Hacker, Viktor; Arenz, Matthias

    2014-12-01

    In the presented work we systematically study the influence of phosphoric acid, ammonium trifluoromethanesulfonate (ATFMS), and polyvinylidene difluoride (PVDF) on the oxygen reduction reaction (ORR) activity of carbon supported, Pt based catalysts. The influence of phosphoric acid is investigated in a mixed solution of perchloric acid with small amounts of phosphoric acid added. Thin-film rotating disk electrode (TF-RDE) measurements show that such a mixed electrolyte is advantageous as the oxygen reduction reaction (ORR) is inhibited without influencing the oxygen solubility in the electrolyte. In contrast to previous reports it is seen when investigating additives that ATFMS acts as a catalyst poison; whereas the results provide evidence of a better performance in case of the PVDF incorporated catalysts as compared to reference samples without PVDF. The technological relevance of the PVDF improvements and its stability over prolonged time was validated by membrane electrode assembly (MEA) tests.

  5. Colorimetric determination of phosphoric acid leakage for phosphoric acid-doped polybenzimidazole membrane fuel cell applications

    NASA Astrophysics Data System (ADS)

    Jeong, Yeon Hun; Jung, Ju Hae; Choi, Euiji; Han, Seungyoon; Begley, Alina Irene; Yoo, Sung Jong; Jang, Jong Hyun; Kim, Hyoung-Juhn; Nam, Suk Woo; Lee, Kwan-Young; Kim, Jin Young

    2015-12-01

    A simple and precise colorimetric method for analyzing phosphoric acid leakage in phosphoric acid-doped polybenzimidazole membrane fuel cells is described. The developed method is based on the colorimetric determination from a rapid formation of molybdenum blue color by the reduction reaction of molybdate ions in the presence of phosphoric acid in the acidic medium. The color is stable up to a few months and can be used for the sensitive and accurate detection of phosphoric acid electrolyte which is discharged from the fuel cell during operation. Tests with a wide concentration range of phosphate compounds showed that it permits determination of phosphoric acid up to nanogram quantities. The developed detection method assists monitoring the phosphoric acid contents and developing stable operation strategies of fuel cells.

  6. Drastic Enhancement of Photocatalytic Activities over Phosphoric Acid Protonated Porous g-C3 N4 Nanosheets under Visible Light.

    PubMed

    Shi, Li; Chang, Kun; Zhang, Huabin; Hai, Xiao; Yang, Liuqing; Wang, Tao; Ye, Jinhua

    2016-08-01

    A simple method is developed to fabricate protonated porous graphitic carbon nitride nanosheets (P-PCNNS) by protonation-exfoliation of bulk graphitic carbon nitride (BCN) with phosphoric acid (H3 PO4 ). The H3 PO4 treatment not only helps to exfoliate the BCN into 2D ultrathin nanosheets with abundant micro- and mesopores, endowing P-PCNNS with more exposed active catalytic sites and cross-plane diffusion channels to facilitate the mass and charge transport, but also induces the protonation of carbon nitride polymer, leading to the moderate removal of the impurities of carbon species in BCN for the optimization of the aromatic π-conjugated system for better charge separation without changing its chemical structure. As a result, the P-PCNNS show much higher photocatalytic performance for hydrogen evolution and CO2 conversion than bare BCN and graphitic carbon nitride nanosheets. PMID:27410192

  7. Determination of Activity Coefficients of di-(2-ethylhexyl) Phosphoric Acid Dimer in Select Organic Solvents Using Vapor Phase Osmometry

    SciTech Connect

    Michael F. Gray; Peter Zalupski; Mikael Nilsson

    2013-08-01

    Effective models for solvent extraction require accurate characterization of the nonideality effects for each component, including the extractants. In this study, the nonideal behavior of the industrial extractant di(2-ethylhexyl) phosphoric acid has been investigated using vapor pressure osmometry (VPO). From the osmometry data, activity coefficients for the HDEHP dimer were obtained based on a formulation of the regular solution theory of Scatchard and Hildebrand, and the Margules two- and three-suffix equations. The results show similarity with a slope-analysis based relation from previous literature, although important differences are highlighted. The work points towards VPO as a useful technique for this type of study, but care must be taken with the choice of standard and method of analysis.

  8. 46 CFR 153.558 - Special requirements for phosphoric acid.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Special requirements for phosphoric acid. 153.558... Equipment Special Requirements § 153.558 Special requirements for phosphoric acid. A phosphoric acid... phosphoric acid tanks by the Commandant (CG-ENG); or (c) Made of a stainless steel that resists corrosion...

  9. 46 CFR 153.558 - Special requirements for phosphoric acid.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Special requirements for phosphoric acid. 153.558... Equipment Special Requirements § 153.558 Special requirements for phosphoric acid. A phosphoric acid... phosphoric acid tanks by the Commandant (CG-ENG); or (c) Made of a stainless steel that resists corrosion...

  10. 46 CFR 153.558 - Special requirements for phosphoric acid.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Special requirements for phosphoric acid. 153.558... Equipment Special Requirements § 153.558 Special requirements for phosphoric acid. A phosphoric acid... phosphoric acid tanks by the Commandant (CG-ENG); or (c) Made of a stainless steel that resists corrosion...

  11. 46 CFR 153.558 - Special requirements for phosphoric acid.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Special requirements for phosphoric acid. 153.558... Equipment Special Requirements § 153.558 Special requirements for phosphoric acid. A phosphoric acid... phosphoric acid tanks by the Commandant (CG-522); or (c) Made of a stainless steel that resists corrosion...

  12. 46 CFR 153.558 - Special requirements for phosphoric acid.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Special requirements for phosphoric acid. 153.558... Equipment Special Requirements § 153.558 Special requirements for phosphoric acid. A phosphoric acid... phosphoric acid tanks by the Commandant (CG-522); or (c) Made of a stainless steel that resists corrosion...

  13. Corrosion free phosphoric acid fuel cell

    DOEpatents

    Wright, Maynard K.

    1990-01-01

    A phosphoric acid fuel cell with an electrolyte fuel system which supplies electrolyte via a wick disposed adjacent a cathode to an absorbent matrix which transports the electrolyte to portions of the cathode and an anode which overlaps the cathode on all sides to prevent corrosion within the cell.

  14. 40 CFR 721.6097 - Phosphoric acid derivative (generic name).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Phosphoric acid derivative (generic... Specific Chemical Substances § 721.6097 Phosphoric acid derivative (generic name). (a) Chemical substance... phosphoric acid derivative (PMN P-95-284) is subject to reporting under this section for the significant...

  15. 40 CFR 721.6097 - Phosphoric acid derivative (generic name).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Phosphoric acid derivative (generic... Specific Chemical Substances § 721.6097 Phosphoric acid derivative (generic name). (a) Chemical substance... phosphoric acid derivative (PMN P-95-284) is subject to reporting under this section for the significant...

  16. 40 CFR 721.6097 - Phosphoric acid derivative (generic name).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Phosphoric acid derivative (generic... Specific Chemical Substances § 721.6097 Phosphoric acid derivative (generic name). (a) Chemical substance... phosphoric acid derivative (PMN P-95-284) is subject to reporting under this section for the significant...

  17. 40 CFR 721.10431 - Phosphoric acid esters (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Phosphoric acid esters (generic). 721... Substances § 721.10431 Phosphoric acid esters (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substances identified generically as phosphoric acid esters (PMNs...

  18. 40 CFR 721.10431 - Phosphoric acid esters (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Phosphoric acid esters (generic). 721... Substances § 721.10431 Phosphoric acid esters (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substances identified generically as phosphoric acid esters (PMNs...

  19. 40 CFR 721.10685 - Phosphoric acid, mixed esters (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Phosphoric acid, mixed esters (generic... Specific Chemical Substances § 721.10685 Phosphoric acid, mixed esters (generic). (a) Chemical substance... phosphoric acid, mixed esters (PMN P-13-170) is subject to reporting under this section for the...

  20. 40 CFR 721.6097 - Phosphoric acid derivative (generic name).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Phosphoric acid derivative (generic... Specific Chemical Substances § 721.6097 Phosphoric acid derivative (generic name). (a) Chemical substance... phosphoric acid derivative (PMN P-95-284) is subject to reporting under this section for the significant...

  1. 40 CFR 721.6097 - Phosphoric acid derivative (generic name).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Phosphoric acid derivative (generic... Specific Chemical Substances § 721.6097 Phosphoric acid derivative (generic name). (a) Chemical substance... phosphoric acid derivative (PMN P-95-284) is subject to reporting under this section for the significant...

  2. Laser-activated remote phosphor conversion with ceramic phosphors

    NASA Astrophysics Data System (ADS)

    Lenef, Alan; Kelso, John; Tchoul, Maxim; Mehl, Oliver; Sorg, Jörg; Zheng, Y.

    2014-09-01

    Direct laser activation of a remote phosphor, or LARP, is a highly effective approach for producing very high luminance solid-state light sources. Such sources have much smaller étendue than LEDs of similar power, thereby greatly increasing system luminous fluxes in projection and display applications. While several commercial products now employ LARP technology, most current configurations employ phosphor powders in a silicone matrix deposited on rotating wheels. These provide a low excitation duty cycle that helps limit quenching and thermal overload. These systems already operate close to maximum achievable pump powers and intensities. To further increase power scaling and eliminate mechanical parts to achieve smaller footprints, OSRAM has been developing static LARP systems based on high-thermal conductivity monolithic ceramic phosphors. OSRAM has recently introduced a static LARP product using ceramic phosphor for endoscopy and also demonstrated a LARP concept for automotive forward lighting1. We first discuss the basic LARP concept with ceramic phosphors, showing how their improved thermal conductivity can achieve both high luminous fluxes and luminance in a static configuration. Secondly, we show the importance of scattering and low optical losses to achieving high overall efficiency and light extraction. This is shown through experimental results and radiation transport calculations. Finally, we discuss some of the fundamental factors which limit the ultimate luminance achievable with ceramic converted LARP, including optical pumping effects and thermal quenching.

  3. Phosphoric Acid Fuel Cell Technology Status

    NASA Technical Reports Server (NTRS)

    Simons, S. N.; King, R. B.; Prokopius, P. R.

    1981-01-01

    A review of the current phosphoric acid fuel cell system technology development efforts is presented both for multimegawatt systems for electric utility applications and for multikilowatt systems for on-site integrated energy system applications. Improving fuel cell performance, reducing cost, and increasing durability are the technology drivers at this time. Electrodes, matrices, intercell cooling, bipolar/separator plates, electrolyte management, and fuel selection are discussed.

  4. Radionuclide concentrations in raw and purified phosphoric acids from Brazil and their processing wastes: implications for radiation exposures.

    PubMed

    da Conceição, Fabiano Tomazini; Antunes, Maria Lúcia Pereira; Durrant, Steven F

    2012-02-01

    Radionuclides from the U and Th natural series are present in alkaline rocks, which are used as feedstock in Brazil for the production of raw phosphoric acid, which can be considered as a NORM (naturally occurring radioactive material). As a result of the purification of raw phosphoric acid to food-grade phosphoric acid, two by-products are generated, i.e., solid and liquid wastes. Taking this into account, the main aim of this study was to evaluate the fluxes of natural radionuclide in the production of food-grade phosphoric acids in Brazil, to determine the radiological impact caused by ingestion of food-grade phosphoric acid, and to evaluate the solid waste environmental hazards caused by its application in crop soils. Radiological characterization of raw phosphoric acid, food-grade phosphoric acid, solid waste, and liquid waste was performed by alpha and gamma spectrometry. The (238)U, (234)U, (226)Ra, and (232)Th activity concentrations varied depending on the source of raw phosphoric acid. Decreasing radionuclides activity concentrations in raw phosphoric acids used by the producer of the purified phosphoric acid were observed as follows: Tapira (raw phosphoric acid D) > Catalão (raw phosphoric acids B and C) > Cajati (raw phosphoric acid A). The industrial purification process produces a reduction in radionuclide activity concentrations in food-grade phosphoric acid in relation to raw phosphoric acid produced in plant D and single raw phosphoric acid used in recent years. The most common use of food-grade phosphoric acid is in cola soft drinks, with an average consumption in Brazil of 72 l per person per year. Each liter of cola soft drink contains 0.5 ml of food-grade phosphoric acid, which gives an annual average intake of 36 ml of food-grade phosphoric acid per person. Under these conditions, radionuclide intake through consumption of food-grade phosphoric acid per year per person via cola soft drinks is not hazardous to human health in Brazil

  5. Microscopic and mesoscopic structural features of an activated carbon sample, prepared from sorghum via activation by phosphoric acid

    SciTech Connect

    Temleitner, László; Pusztai, László; Rubio-Arroyo, Manuel F.; Aguilar-López, Sergio; Pizio, Orest

    2012-12-15

    Graphical abstract: Display Omitted Highlights: ► Preparation of a new activated carbon sample from sorghum. ► Characterization by adsorption/desorption methods. ► Determination of the structure by synchrotron X-ray diffraction. ► The sample is amorphous and contains distorted graphene fragments. ► A characteristic nanoscale distance is established from the radial distribution function. -- Abstract: An acidic chemical activation procedure has been used for preparing activated carbon with a surface area exceeding 1000 m{sup 2}/g from sorghum. In order to reveal structural features, synchrotron X-ray diffraction measurements have been performed. The structure of the material has been characterized by the total scattering structure factor and the radial distribution function describing short-range arrangement of atoms at distances of the order of a few atomic diameters as well as correlations at a longer scale, of the order of nanometers. The atomic arrangement has been found to be consistent with that of amorphous graphite-like carbon. As far as the mesoscopic structure is concerned, the presence of a characteristic distance is suggested on the basis of the clear nanometer scale oscillations of the radial distribution function, which distance may be assigned as the mesopore size in the material. It is suggested that the approach devized here may later be applied routinely for other activated carbon samples, too, for characterizing atomic and nanoscale order simultaneously.

  6. 40 CFR 422.50 - Applicability; description of the defluorinated phosphoric acid subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... defluorinated phosphoric acid subcategory. 422.50 Section 422.50 Protection of Environment ENVIRONMENTAL... Defluorinated Phosphoric Acid Subcategory § 422.50 Applicability; description of the defluorinated phosphoric... defluorination of phosphoric acid. Wet process phosphoric acid is dehydrated by application of heat and...

  7. 40 CFR 422.50 - Applicability; description of the defluorinated phosphoric acid subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... defluorinated phosphoric acid subcategory. 422.50 Section 422.50 Protection of Environment ENVIRONMENTAL... Defluorinated Phosphoric Acid Subcategory § 422.50 Applicability; description of the defluorinated phosphoric... defluorination of phosphoric acid. Wet process phosphoric acid is dehydrated by application of heat and...

  8. 40 CFR 422.50 - Applicability; description of the defluorinated phosphoric acid subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... defluorinated phosphoric acid subcategory. 422.50 Section 422.50 Protection of Environment ENVIRONMENTAL... Defluorinated Phosphoric Acid Subcategory § 422.50 Applicability; description of the defluorinated phosphoric... defluorination of phosphoric acid. Wet process phosphoric acid is dehydrated by application of heat and...

  9. 40 CFR 422.50 - Applicability; description of the defluorinated phosphoric acid subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... defluorinated phosphoric acid subcategory. 422.50 Section 422.50 Protection of Environment ENVIRONMENTAL... Defluorinated Phosphoric Acid Subcategory § 422.50 Applicability; description of the defluorinated phosphoric... defluorination of phosphoric acid. Wet process phosphoric acid is dehydrated by application of heat and...

  10. 40 CFR 422.50 - Applicability; description of the defluorinated phosphoric acid subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... defluorinated phosphoric acid subcategory. 422.50 Section 422.50 Protection of Environment ENVIRONMENTAL... Defluorinated Phosphoric Acid Subcategory § 422.50 Applicability; description of the defluorinated phosphoric... defluorination of phosphoric acid. Wet process phosphoric acid is dehydrated by application of heat and...

  11. Acid distribution in phosphoric acid fuel cells

    SciTech Connect

    Okae, I.; Seya, A.; Umemoto, M.

    1996-12-31

    Electrolyte acid distribution among each component of a cell is determined by capillary force when the cell is not in operation, but the distribution under the current load conditions had not been clear so far. Since the loss of electrolyte acid during operation is inevitable, it is necessary to store enough amount of acid in every cell. But it must be under the level of which the acid disturbs the diffusion of reactive gases. Accordingly to know the actual acid distribution during operation in a cell is very important. In this report, we carried out experiments to clarify the distribution using small single cells.

  12. Cathode catalysts for primary phosphoric acid fuel cells

    NASA Technical Reports Server (NTRS)

    1981-01-01

    Alkylation or carbon Vulcan XC-72, the support carbon, was shown to provide the most stable bond type for linking cobalt dehydrodibenzo tetraazannulene (CoTAA) to the surface of the carbon; this result is based on data obtained by cyclic voltammetry, pulse voltammetry and by release of 14C from bonded CoTAA. Half-cell tests at 100 C in 85% phosphoric acid showed that CoTAA bonded to the surface of carbon (Vulcan XC-72) via an alkylation procedure is a more active catalyst than is platinum based on a factor of two improvement in Tafel slope; dimeric CoTAA had catalytic activity equal to platinum. Half-cell tests also showed that bonded CoTAA catalysts do not suffer a loss in potential when air is used as a fuel rather than oxygen. Commercially available polytetrafluroethylene (PTFE) was shown to be unstable in the fuel cell environment with degradation occurring in 2000 hours or less. The PTFE was stressed at 200 C in concentrated phosphoric acid as well as electrochemically stressed in 150 C concentrated phosphoric acid; the surface chemistry of PTFE was observed to change significantly. Radiolabeled PTFE was prepared and used to verify that such chemical changes also occur in the primary fuel cell environment.

  13. Stabilizing platinum in phosphoric acid fuel cells

    NASA Technical Reports Server (NTRS)

    Remick, R. J.

    1981-01-01

    The cathode of the phosphoric acid fuel cell uses a high surface area platinum catalyst supported on a carbon substrate. During operation, the small platinum crystallites sinter, causing loss in cell performance. A support was developed that stabilizes platinum in the high surface area condition by retarding or preventing the sintering process. The approach is to form etch pits in the carbon by oxidizing the carbon in the presence of a metal oxide catalyst, remove the metal oxide by an acid wash, and then deposit platinum in these pits. Results confirm the formation of etch pits in each of the three supports chosen for investigation: Vulcan XC-72R, Vulcan XC-72 that was graphized at 2500 C, and Shawinigan Acetylene Black.

  14. World wide IFC phosphoric acid fuel cell implementation

    SciTech Connect

    King, J.M. Jr

    1996-04-01

    International Fuel Cells, a subsidary of United technologies Corporation, is engaged in research and development of all types of fuel cell technologies and currently manufactures alkaline fuel cell power plants for the U.S. manned space flight program and natural gas fueled stationary power plants using phosphoric acid fuel cells. This paper describes the phosphoric acid fuel cell power plants.

  15. Method for incorporating radioactive phosphoric acid solutions in concrete

    DOEpatents

    Wolf, Gary A [Kennewick, WA; Smith, Jeffrey W [Lancaster, OH; Ihle, Nathan C [Walla Walla, WA

    1984-01-01

    A method for incorporating radioactive phosphoric acid solutions in concrete is described wherein the phosphoric acid is reacted with Ca(OH).sub.2 to form a precipitate of hydroxyapatite and the hydroxyapatite is mixed with portland cement to form concrete.

  16. Method for incorporating radioactive phosphoric acid solutions in concrete

    DOEpatents

    Wolf, G.A.; Smith, J.W.; Ihle, N.C.

    1982-07-08

    A method for incorporating radioactive phosphoric acid solutions in concrete is described wherein the phosphoric acid is reacted with Ca(OH)/sub 2/ to form a precipitate of hydroxyapatite and the hydroxyapatite is mixed with Portland cement to form concrete.

  17. Enantioselective synthesis of benzazepinoindoles bearing trifluoromethylated quaternary stereocenters catalyzed by chiral spirocyclic phosphoric acids.

    PubMed

    Li, Xuejian; Chen, Di; Gu, Haorui; Lin, Xufeng

    2014-07-18

    The first highly enantioselective iso-Pictet-Spengler reaction of C-2-linked o-aminobenzylindoles with trifluoromethyl ketones was developed using chiral spirocyclic phosphoric acids as organocatalysts, which afforded optically active benzazepinoindoles bearing trifluoromethylated quaternary stereocenters. PMID:24890313

  18. Crystalline rare-earth activated oxyorthosilicate phosphor

    DOEpatents

    McClellan, Kenneth J.; Cooke, D. Wayne

    2004-02-10

    Crystalline, transparent, rare-earth activated lutetium oxyorthosilicate phosphor. The phosphor consists essentially of lutetium yttrium oxyorthosilicate activated with a rare-earth metal dopant M and having the general formula Lu(.sub.2-x-z)Y.sub.x M.sub.z SiO.sub.5, wherein 0.00.ltoreq.x.ltoreq.1.95, wherein 0.001.ltoreq.z.ltoreq.0.02, and wherein M is selected from Sm, Tb, Tm, Eu, Yb, and Pr. The phosphor also consists essentially of lutetium gadolinium oxyorthosilicate activated with a rare-earth metal dopant M and having the general formula Lu(.sub.2-x-z)Gd.sub.x M.sub.z SiO.sub.5, wherein 0.00.ltoreq.x.ltoreq.1.95, wherein 0.001.ltoreq.z.ltoreq.0.02, and wherein M is selected from Sm, Tb, Tm, Eu, Yb, and Pr. The phosphor also consists essentially of gadolinium yttrium oxyorthosilicate activated with a rare-earth metal dopant M and having the general formula Gd(.sub.2-x-z)Y.sub.x M.sub.z SiO.sub.5, wherein 0.00.ltoreq.x.ltoreq.1.95, wherein 0.001.ltoreq.z.ltoreq.0.02, and wherein M is selected from Sm, Tb, Tm, Eu, Yb, and Pr. The phosphor may be optically coupled to a photodetector to provide a radiation detector.

  19. Addition of Grape Seed Extract Renders Phosphoric Acid a Collagen-stabilizing Etchant.

    PubMed

    Liu, Y; Dusevich, V; Wang, Y

    2014-08-01

    Previous studies found that grape seed extract (GSE), which is rich in proanthocyanidins, could protect demineralized dentin collagen from collagenolytic activities following clinically relevant treatment. Because of proanthocyanidin's adverse interference to resin polymerization, it was believed that GSE should be applied and then rinsed off in a separate step, which in effect increases the complexity of the bonding procedure. The present study aimed to investigate the feasibility of combining GSE treatment with phosphoric acid etching to address the issue. It is also the first attempt to formulate collagen-cross-linking dental etchants. Based on Fourier-transformed infrared spectroscopy and digestion assay, it was established that in the presence of 20% to 5% phosphoric acid, 30 sec of GSE treatment rendered demineralized dentin collagen inert to bacterial collagenase digestion. Based on this positive result, the simultaneous dentin etching and collagen protecting of GSE-containing phosphoric acid was evaluated on the premise of a 30-second etching time. According to micro-Raman spectroscopy, the formulation containing 20% phosphoric acid was found to lead to overetching. Based on scanning and transmission electronic microscopy, this same formulation exhibited unsynchronized phosphoric acid and GSE penetration. Therefore, addition of GSE did render phosphoric acid a collagen-stabilizing etchant, but the preferable phosphoric acid concentration should be <20%. PMID:24935065

  20. Proton Conductivity in Phosphoric Acid: The Role of Quantum Effects

    NASA Astrophysics Data System (ADS)

    Heres, M.; Wang, Y.; Griffin, P. J.; Gainaru, C.; Sokolov, A. P.

    2016-10-01

    Phosphoric acid has one of the highest intrinsic proton conductivities of any known liquids, and the mechanism of this exceptional conductivity remains a puzzle. Our detailed experimental studies discovered a strong isotope effect in the conductivity of phosphoric acids caused by (i) a strong isotope shift of the glass transition temperature and (ii) a significant reduction of the energy barrier by zero-point quantum fluctuations. These results suggest that the high conductivity in phosphoric acids is caused by a very efficient proton transfer mechanism, which is strongly assisted by quantum effects.

  1. Ionic conductivity and glass transition of phosphoric acids

    SciTech Connect

    Wang, Yangyang; Lane, Nathan A; Sun, Che-Nan; Fan, Fei; Zawodzinski, Thomas; Sokolov, Alexei P

    2013-01-01

    Here we report the low-temperature dielectric and viscoelastic properties of phosphoric acids in the range of H2O:P2O5 1.5 5. Both dielectric and viscosity measurements allow us to determine the glass-transition temperatures of phosphoric acids. The obtained glass-transition temperatures are in good agreement with previous differential scanning calorimetric measurements. Moreover, our analysis reveals moderate decoupling of ionic conductivity from structural relaxation in the vicinity of the glass transition.

  2. Materials characterization of phosphoric acid fuel cell system

    NASA Technical Reports Server (NTRS)

    Venkatesh, Srinivasan

    1986-01-01

    The component materials used in the fabrication of phosphoric acid fuel cells (PAFC) must have mechanical, chemical, and electrochemical stability to withstand the moderately high temperature (200 C) and pressure (500 kPa) and highly oxidizing nature of phosphoric acid. This study discusses the chemical and structural stability, performance and corrosion data on certain catalysts, catalyst supports, and electrode support materials used in PAFC applications.

  3. Ionic Ckonductivity and Glass Transition of Phosphoric Acids

    SciTech Connect

    Wang, Yangyang; Lane, Nathan A; Sun, Che-Nan; Fan, Fei; Zawodzinski, Thomas; Sokolov, Alexei P

    2013-01-01

    Here we report the low-temperature dielectric and viscoelastic properties of phosphoric acids in the range of H2O:P2O5 1.5 5. Both dielectric and viscosity measurements allow us to determine the glass-transition temperatures of phosphoric acids. The obtained glass-transition temperatures are in good agreement with previous differential scanning calorimetric measurements. Moreover, our analysis reveals moderate decoupling of ionic conductivity from structural relaxation in the vicinity of the glass transition.

  4. Phosphoric acid fuel cell platinum use study

    NASA Technical Reports Server (NTRS)

    Lundblad, H. L.

    1983-01-01

    The U.S. Department of Energy is promoting the private development of phosphoric acid fuel cell (PAFC) power plants for terrestrial applications. Current PAFC technology utilizes platinum as catalysts in the power electrodes. The possible repercussions that the platinum demand of PAFC power plant commercialization will have on the worldwide supply and price of platinum from the outset of commercialization to the year 2000 are investigated. The platinum demand of PAFC commercialization is estimated by developing forecasts of platinum use per unit of generating capacity and penetration of PAFC power plants into the electric generation market. The ability of the platinum supply market to meet future demands is gauged by assessing the size of platinum reserves and the capability of platinum producers to extract, refine and market sufficient quantities of these reserves. The size and timing of platinum price shifts induced by the added demand of PAFC commercialization are investigated by several analytical methods. Estimates of these price shifts are then used to calculate the subsequent effects on PAFC power plant capital costs.

  5. New applications for phosphoric acid fuel cells

    NASA Technical Reports Server (NTRS)

    Stickles, R. P.; Breuer, C. T.

    1983-01-01

    New applications for phosphoric acid fuel cells were identified and evaluated. Candidates considered included all possibilities except grid connected electric utility applications, on site total energy systems, industrial cogeneration, opportunistic use of waste hydrogen, space and military applications, and applications smaller than 10 kW. Applications identified were screened, with the most promising subjected to technical and economic evaluation using a fuel cell and conventional power system data base developed in the study. The most promising applications appear to be the underground mine locomotive and the railroad locomotive. Also interesting are power for robotic submersibles and Arctic villages. The mine locomotive is particularly attractive since it is expected that the fuel cell could command a very high price and still be competitive with the conventionally used battery system. The railroad locomotive's attractiveness results from the (smaller) premium price which the fuel cell could command over the conventional diesel electric system based on its superior fuel efficiency, and on the large size of this market and the accompanying opportunities for manufacturing economy.

  6. New applications for phosphoric acid fuel cells

    SciTech Connect

    Stickles, R.P.; Breuer, C.T.

    1983-11-01

    New applications for phosphoric acid fuel cells were identified and evaluated. Candidates considered included all possibilities except grid connected electric utility applications, on-site total energy systems, industrial co-generation, opportunistic use of waste hydrogen, space and military applications, and applications smaller than 10 kW. Applications identified were screened, with the most promising subjected to technical and economic evaluation using a fuel cell and conventional power system data base developed in the study. The most promising applications appear to be the underground mine locomotive and the railroad locomotive. Also interesting is power for robotic submersibles and Arctic villages. The mine locomotive is particularly attractive since it is expected that the fuel cell could command a very high price and still be competitive with the conventionally used battery system. The railroad locomotive's attractiveness results from the (smaller) premium price which the fuel cell could command over the conventional diesel electric system based on its superior fuel efficiency, and on the large size of this market and the accompanying opportunities for manufacturing economy.

  7. Phosphoric acid fuel cell platinum use study

    NASA Astrophysics Data System (ADS)

    Lundblad, H. L.

    1983-05-01

    The U.S. Department of Energy is promoting the private development of phosphoric acid fuel cell (PAFC) power plants for terrestrial applications. Current PAFC technology utilizes platinum as catalysts in the power electrodes. The possible repercussions that the platinum demand of PAFC power plant commercialization will have on the worldwide supply and price of platinum from the outset of commercialization to the year 2000 are investigated. The platinum demand of PAFC commercialization is estimated by developing forecasts of platinum use per unit of generating capacity and penetration of PAFC power plants into the electric generation market. The ability of the platinum supply market to meet future demands is gauged by assessing the size of platinum reserves and the capability of platinum producers to extract, refine and market sufficient quantities of these reserves. The size and timing of platinum price shifts induced by the added demand of PAFC commercialization are investigated by several analytical methods. Estimates of these price shifts are then used to calculate the subsequent effects on PAFC power plant capital costs.

  8. Effects of phosphoric acid on the lead-acid battery reactions

    NASA Astrophysics Data System (ADS)

    Ikeda, Osamu; Iwakura, Chiaki; Yoneyama, Hiroshi; Tamura, Hideo

    1986-10-01

    The addition of a small amount of phosphoric acid to 5 M H2SO4 (commercial electrolyte of lead-acid batteries) results in various positive effects on the lead-acid battery reactions: (1) depression of the corrosion rate of the lead substrate through a preferential formation of alpha-PbO2 on the substrate surface; (2) retardation of hard sulfate formation or of deactivation of active materials; and (3) change in the crystal morphology of PbSO2 formed on the discharge of PbO2. Most of these effects results from chemisorption of phosphoric acid on PbSO4 crystals produced in the discharge process of PbO2.

  9. Antimicrobial and cytotoxic effects of phosphoric acid solution compared to other root canal irrigants

    PubMed Central

    PRADO, Maíra; da SILVA, Emmanuel João Nogueira Leal; DUQUE, Thais Mageste; ZAIA, Alexandre Augusto; FERRAZ, Caio Cezar Randi; de ALMEIDA, José Flávio Affonso; GOMES, Brenda Paula Figueiredo de Almeida

    2015-01-01

    Phosphoric acid has been suggested as an irrigant due to its effectiveness in removing the smear layer. Objectives : The purpose of this study was to compare the antimicrobial and cytotoxic effects of a 37% phosphoric acid solution to other irrigants commonly used in endodontics. Material and Methods : The substances 37% phosphoric acid, 17% EDTA, 10% citric acid, 2% chlorhexidine (solution and gel), and 5.25% NaOCl were evaluated. The antimicrobial activity was tested against Candida albicans, Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Actinomyces meyeri, Parvimonas micra, Porphyromonas gingivalis, and Prevotella nigrescens according to the agar diffusion method. The cytotoxicity of the irrigants was determined by using the MTT assay. Results : Phosphoric acid presented higher antimicrobial activity compared to the other tested irrigants. With regard to the cell viability, this solution showed results similar to those with 5.25% NaOCl and 2% chlorhexidine (gel and solution), whereas 17% EDTA and 10% citric acid showed higher cell viability compared to other irrigants. Conclusion : Phosphoric acid demonstrated higher antimicrobial activity and cytotoxicity similar to that of 5.25% NaOCl and 2% chlorhexidine (gel and solution). PMID:26018307

  10. Enhanced photocatalytic activity of Cl-residual rutile TiO2 nanorods after targeted co-modification with phosphoric and boric acids.

    PubMed

    Wu, Jing; Cui, Haiqin; Zhang, Xuliang; Luan, Yunbo; Jing, Liqiang

    2015-06-28

    The promotion of O2 adsorption on semiconductor surfaces for effectively capturing photogenerated electrons in the photocatalytic degradation of pollutants is highly desired. In this study, the targeted co-modification of residual chlorine rutile TiO2 nanorods with phosphoric and boric acids has been accomplished for the first time by simple wet chemical processes. The key to targeted co-modification is to connect -P-OH and -B-OH to the Cl-residual TiO2 surfaces by -Ti-OH and -Ti-Cl, respectively, consequently forming -Ti-O-P-OH and -Ti-Cl:B-OH ends. By means of the atmosphere-controlled surface photovoltage spectroscopy, the degrees for capturing photogenerated electrons by the adsorbed O2 as receptors on the resulting TiO2 nanorods are quantitatively analyzed. It is confirmed that the targeted co-modification could greatly promote the capture of the photogenerated electrons compared to the phosphate and borate modification alone. This is attributed to increased amounts of adsorbed O2 based on electrochemical O2 reduction and O2 temperature-programmed desorption measurements, further leading to the enhanced separation of photogenerated charges, characterized by an increase in the amount of produced hydroxyl radicals. This is responsible for the obviously enhanced photocatalytic activity of TiO2 nanorods towards the degradation of colorless gas-phase acetaldehyde and liquid-phase phenol. This work would provide us a feasible route for the co-modification with inorganic acids to synthesize efficient nanosized TiO2-based photocatalysts.

  11. 40 CFR 721.6200 - Fatty acid polyamine condensate, phosphoric acid ester salts.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Fatty acid polyamine condensate, phosphoric acid ester salts. 721.6200 Section 721.6200 Protection of Environment ENVIRONMENTAL PROTECTION... New Uses for Specific Chemical Substances § 721.6200 Fatty acid polyamine condensate, phosphoric...

  12. Technology development for phosphoric acid fuel cell powerplant (phase 2)

    NASA Technical Reports Server (NTRS)

    Christner, L.

    1979-01-01

    The status of technology for the manufacturing and testing of 1200 sq. cm cell materials, components, and stacks for on-site integrated energy systems is assessed. Topics covered include: (1) preparation of thin layers of silicon carbide; (2) definition and control schemes for volume changes in phosphoric acid fuel cells; (3) preparation of low resin content graphite phenolic resin composites; (4) chemical corrosion of graphite-phenolic resin composites in hot phosphoric acid; (5) analysis of electrical resistance of composite materials for fuel cells; and (6) fuel cell performance and testing.

  13. Corrosion-resistant catalyst supports for phosphoric acid fuel cells

    SciTech Connect

    Kosek, J.A.; Cropley, C.C.; LaConti, A.B.

    1990-01-01

    High-surface-area carbon blacks such as Vulcan XC-72 (Cabot Corp.) and graphitized carbon blacks such as 2700{degree}C heat-treated Black Pearls 2000 (HTBP) (Cabot Corp.) have found widespread applications as catalyst supports in phosphoric acid fuel cells (PAFCs). However, due to the operating temperatures and pressures being utilized in PAFCs currently under development, the carbon-based cathode catalyst supports suffer from corrosion, which decreases the performance and life span of a PAFC stack. The feasibility of using alternative, low-cost, corrosion-resistant catalyst support (CRCS) materials as replacements for the cathode carbon support materials was investigated. The objectives of the program were to prepare high-surface-area alternative supports and to evaluate the physical characteristics and the electrochemical stability of these materials. The O{sub 2} reduction activity of the platinized CRCS materials was also evaluated. 2 refs., 3 figs.

  14. The first catalytic asymmetric thioacetalization by chiral phosphoric acid catalysis.

    PubMed

    Yu, Jin-Sheng; Wu, Wen-Biao; Zhou, Feng

    2016-02-21

    We report here the first catalytic asymmetric thioacetalization of salicylaldehyde and dithiol. Chiral phosphoric acid STRIP C5 is identified as a powerful catalyst for this reaction to afford various chiral dithioacetals in high to excellent yields and enantioselectivities under mild conditions. PMID:26810819

  15. Corrosion of graphite composites in phosphoric acid fuel cells

    NASA Technical Reports Server (NTRS)

    Christner, L. G.; Dhar, H. P.; Farooque, M.; Kush, A. K.

    1986-01-01

    Polymers, polymer-graphite composites and different carbon materials are being considered for many of the fuel cell stack components. Exposure to concentrated phosphoric acid in the fuel cell environment and to high anodic potential results in corrosion. Relative corrosion rates of these materials, failure modes, plausible mechanisms of corrosion and methods for improvement of these materials are investigated.

  16. 46 CFR 151.50-23 - Phosphoric acid.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES BARGES CARRYING BULK LIQUID HAZARDOUS MATERIAL CARGOES Special Requirements § 151.50-23 Phosphoric acid. (a) The term... transported in bulk cargo tanks except upon authorization by the Commandant (CG-522). (f) The requirements...

  17. 46 CFR 151.50-23 - Phosphoric acid.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES BARGES CARRYING BULK LIQUID HAZARDOUS MATERIAL CARGOES Special Requirements § 151.50-23 Phosphoric acid. (a) The term... transported in bulk cargo tanks except upon authorization by the Commandant (CG-ENG). (f) The requirements...

  18. 46 CFR 151.50-23 - Phosphoric acid.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES BARGES CARRYING BULK LIQUID HAZARDOUS MATERIAL CARGOES Special Requirements § 151.50-23 Phosphoric acid. (a) The term... transported in bulk cargo tanks except upon authorization by the Commandant (CG-ENG). (f) The requirements...

  19. 46 CFR 151.50-23 - Phosphoric acid.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES BARGES CARRYING BULK LIQUID HAZARDOUS MATERIAL CARGOES Special Requirements § 151.50-23 Phosphoric acid. (a) The term... transported in bulk cargo tanks except upon authorization by the Commandant (CG-ENG). (f) The requirements...

  20. 46 CFR 151.50-23 - Phosphoric acid.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES BARGES CARRYING BULK LIQUID HAZARDOUS MATERIAL CARGOES Special Requirements § 151.50-23 Phosphoric acid. (a) The term... transported in bulk cargo tanks except upon authorization by the Commandant (CG-522). (f) The requirements...

  1. 40 CFR 721.6110 - Alkyldi(alkyloxyhydroxypropyl) derivative, phosphoric acid esters, potassium salts.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...) derivative, phosphoric acid esters, potassium salts. 721.6110 Section 721.6110 Protection of Environment...) derivative, phosphoric acid esters, potassium salts. (a) Chemical substance and significant new uses subject...) derivative, phosphoric acid esters, potassium salts (PMN P-91-818) is subject to reporting under this...

  2. 40 CFR 721.10220 - Phosphoric acid, polymer with cycloaliphatic diglycidyl ether, alkylethers (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Phosphoric acid, polymer with... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10220 Phosphoric acid, polymer with... to reporting. (1) The chemical substance identified generically as phosphoric acid, polymer...

  3. 40 CFR 721.10220 - Phosphoric acid, polymer with cycloaliphatic diglycidyl ether, alkylethers (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Phosphoric acid, polymer with... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10220 Phosphoric acid, polymer with... to reporting. (1) The chemical substance identified generically as phosphoric acid, polymer...

  4. 40 CFR 721.10220 - Phosphoric acid, polymer with cycloaliphatic diglycidyl ether, alkylethers (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Phosphoric acid, polymer with... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10220 Phosphoric acid, polymer with... to reporting. (1) The chemical substance identified generically as phosphoric acid, polymer...

  5. 40 CFR 721.6110 - Alkyldi(alkyloxyhydroxypropyl) derivative, phosphoric acid esters, potassium salts.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...) derivative, phosphoric acid esters, potassium salts. 721.6110 Section 721.6110 Protection of Environment...) derivative, phosphoric acid esters, potassium salts. (a) Chemical substance and significant new uses subject...) derivative, phosphoric acid esters, potassium salts (PMN P-91-818) is subject to reporting under this...

  6. 40 CFR 721.10220 - Phosphoric acid, polymer with cycloaliphatic diglycidyl ether, alkylethers (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Phosphoric acid, polymer with... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10220 Phosphoric acid, polymer with... to reporting. (1) The chemical substance identified generically as phosphoric acid, polymer...

  7. 40 CFR 180.1210 - Phosphorous acid; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Phosphorous acid; exemption from the... Exemptions From Tolerances § 180.1210 Phosphorous acid; exemption from the requirement of a tolerance. An exemption from the requirement of a tolerance is established for residues of phosphorous acid and...

  8. 40 CFR 180.1210 - Phosphorous acid; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 24 2014-07-01 2014-07-01 false Phosphorous acid; exemption from the... Exemptions From Tolerances § 180.1210 Phosphorous acid; exemption from the requirement of a tolerance. An exemption from the requirement of a tolerance is established for residues of phosphorous acid and...

  9. 40 CFR 180.1210 - Phosphorous acid; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 25 2013-07-01 2013-07-01 false Phosphorous acid; exemption from the... Exemptions From Tolerances § 180.1210 Phosphorous acid; exemption from the requirement of a tolerance. An exemption from the requirement of a tolerance is established for residues of phosphorous acid and...

  10. 40 CFR 180.1210 - Phosphorous acid; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 24 2011-07-01 2011-07-01 false Phosphorous acid; exemption from the... Exemptions From Tolerances § 180.1210 Phosphorous acid; exemption from the requirement of a tolerance. An exemption from the requirement of a tolerance is established for residues of phosphorous acid and...

  11. 40 CFR 180.1210 - Phosphorous acid; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 25 2012-07-01 2012-07-01 false Phosphorous acid; exemption from the... Exemptions From Tolerances § 180.1210 Phosphorous acid; exemption from the requirement of a tolerance. An exemption from the requirement of a tolerance is established for residues of phosphorous acid and...

  12. Self-activating and doped tantalate phosphors.

    SciTech Connect

    Nyman, May Devan; Rohwer, Lauren Elizabeth Shea

    2011-01-01

    An ideal red phosphor for blue LEDs is one of the biggest challenges for the solid-state lighting industry. The appropriate phosphor material should have good adsorption and emission properties, good thermal and chemical stability, minimal thermal quenching, high quantum yield, and is preferably inexpensive and easy to fabricate. Tantalates possess many of these criteria, and lithium lanthanum tantalate materials warrant thorough investigation. In this study, we investigated red luminescence of two lithium lanthanum tantalates via three mechanisms: (1) Eu-doping, (2) Mn-doping and (3) self-activation of the tantalum polyhedra. Of these three mechanisms, Mn-doping proved to be the most promising. These materials exhibit two very broad adsorption peaks; one in the UV and one in the blue region of the spectrum; both can be exploited in LED applications. Furthermore, Mn-doping can be accomplished in two ways; ion-exchange and direct solid-state synthesis. One of the two lithium lanthanum tantalate phases investigated proved to be a superior host for Mn-luminescence, suggesting the crystal chemistry of the host lattice is important.

  13. Synthesis of novel acid electrolytes for phosphoric acid fuel cells

    NASA Astrophysics Data System (ADS)

    Adcock, James L.

    1988-11-01

    A 40 millimole per hour scale aerosol direct fluorination reactor was constructed. F-Methyl F-4-methoxybutanoate and F-4-methoxybutanoyl fluoride were synthesized by aerosol direct fluorination of methyl 4-methoxybutanoate. Basic hydrolysis of the perfluorinated derivatives produce sodium F-4 methoxybutanoate which was pyrolyzed to F-3-methoxy-1-propene. Purification and shipment of 33 grams of F-3-methoxy-1-propene followed. Syntheses by analogous methods allowed production and shipment of 5 grams of F-3-ethoxy 1-propene, 18 grams of F-3-(2-methoxy.ethoxy) 1-propene, and 37 grams of F-3,3-dimethyl 1-butene. Eighteen grams of F-2,2-dimethyl 1-chloropropane was produced directly and shipped. As suggested by other contractors, 5 grams of F-3-methoxy 1-iodopropane, and 5 grams of F-3-(2-methoxy.ethoxy) 1-iodopropane were produced by converting the respective precursor acid sodium salts produced for olefin synthesis to the silver salts and pyrolyzing them with iodine. Each of these compounds was prepared for the first time by the aerosol fluorination process during the course of the contract. These samples were provided to other Gas Research Institute (GRI) contractors for synthesis of perfluorinated sulfur (VI) and phosphorous (V) acids.

  14. PROCESS FOR RECOVERING URANIUM FROM AQUEOUS PHOSPHORIC ACID LIQUORS

    DOEpatents

    Schmitt, J.M.

    1962-09-01

    A liquid-liquid extraction method is given for recovering uranium values from aqueous solutions. An acidic aqueous solution containing uranium values is contacted with an organic phase comprising an organic diluent and the reaction product of phosphorous pentoxide and a substantially pure dialkylphosphoric acid. The uranium values are transferred to the organic phase even from aqueous solutions containing a high concentration of strong uranium complexing agents such as phosphate ions. (AEC)

  15. A chiral phosphoric acid catalyst for asymmetric construction of 1,3-dioxanes.

    PubMed

    Matsumoto, Akira; Asano, Keisuke; Matsubara, Seijiro

    2015-07-25

    A novel method of enantioselective 1,3-dioxane construction via a hemiacetalization/intramolecular oxy-Michael addition cascade by a chiral phosphoric acid catalyst was developed. The product was successfully transformed into an optically active 1,3-polyol motif, indicating that the proposed reaction can provide useful chiral building blocks for the de novo synthesis of polyketides. PMID:26103581

  16. Solid-state actinide acid phosphites from phosphorous acid melts

    SciTech Connect

    Oh, George N.; Burns, Peter C.

    2014-07-01

    The reaction of UO{sub 3} and H{sub 3}PO{sub 3} at 100 °C and subsequent reaction with dimethylformamide (DMF) produces crystals of the compound (NH{sub 2}(CH{sub 3}){sub 2})[UO{sub 2}(HPO{sub 2}OH)(HPO{sub 3})]. This compound crystallizes in space group P2{sub 1}/n and consists of layers of uranyl pentagonal bipyramids that share equatorial vertices with phosphite units, separated by dimethylammonium. In contrast, the reaction of phosphorous acid and actinide oxides at 210 °C produces a viscous syrup. Subsequent dilution in solvents and use of standard solution-state methods results in the crystallization of two polymorphs of the actinide acid phosphites An(HPO{sub 2}OH){sub 4} (An=U, Th) and of the mixed acid phosphite–phosphite U(HPO{sub 3})(HPO{sub 2}OH){sub 2}(H{sub 2}O)·2(H{sub 2}O). α- and β-An(HPO{sub 2}OH){sub 4} crystallize in space groups C2/c and P2{sub 1}/n, respectively, and comprise a three-dimensional network of An{sup 4+} cations in square antiprismatic coordination corner-sharing with protonated phosphite units, whereas U(HPO{sub 3})(HPO{sub 2}OH){sub 2}(H{sub 2}O){sub 2}·(H{sub 2}O) crystallizes in a layered structure in space group Pbca that is composed of An{sup 4+} cations in square antiprismatic coordination corner-sharing with protonated phosphites and water ligands. We discuss our findings in using solid inorganic reagents to produce a solution-workable precursor from which solid-state compounds can be crystallized. - Graphical abstract: Reaction of UO{sub 3} and H{sub 3}PO{sub 3} at 100 °C and subsequent reaction with DMF produces crystals of (NH{sub 2}(CH{sub 3}){sub 2})[UO{sub 2}(HPO{sub 2}OH)(HPO{sub 3})] with a layered structure. Reaction of phosphorous acid and actinide oxides at 210 °C produces a viscous syrup and further solution-state reactions result in the crystallization of the actinide acid phosphites An(HPO{sub 2}OH){sub 4} (An=U, Th), with a three-dimensional network structure, and the mixed acid phosphite

  17. Solid-state actinide acid phosphites from phosphorous acid melts

    NASA Astrophysics Data System (ADS)

    Oh, George N.; Burns, Peter C.

    2014-07-01

    The reaction of UO3 and H3PO3 at 100 °C and subsequent reaction with dimethylformamide (DMF) produces crystals of the compound (NH2(CH3)2)[UO2(HPO2OH)(HPO3)]. This compound crystallizes in space group P21/n and consists of layers of uranyl pentagonal bipyramids that share equatorial vertices with phosphite units, separated by dimethylammonium. In contrast, the reaction of phosphorous acid and actinide oxides at 210 °C produces a viscous syrup. Subsequent dilution in solvents and use of standard solution-state methods results in the crystallization of two polymorphs of the actinide acid phosphites An(HPO2OH)4 (An=U, Th) and of the mixed acid phosphite-phosphite U(HPO3)(HPO2OH)2(H2O)·2(H2O). α- and β-An(HPO2OH)4 crystallize in space groups C2/c and P21/n, respectively, and comprise a three-dimensional network of An4+ cations in square antiprismatic coordination corner-sharing with protonated phosphite units, whereas U(HPO3)(HPO2OH)2(H2O)2·(H2O) crystallizes in a layered structure in space group Pbca that is composed of An4+ cations in square antiprismatic coordination corner-sharing with protonated phosphites and water ligands. We discuss our findings in using solid inorganic reagents to produce a solution-workable precursor from which solid-state compounds can be crystallized.

  18. Enzymatic saccharification coupling with polyester recovery from cotton-based waste textiles by phosphoric acid pretreatment.

    PubMed

    Shen, Fei; Xiao, Wenxiong; Lin, Lili; Yang, Gang; Zhang, Yanzong; Deng, Shihuai

    2013-02-01

    In order to recycle the cotton-based waste textiles, a novel process was designed for pretreating waste textiles with phosphoric acid to recover polyester and fermentable sugar. The effects of pretreatment conditions including, phosphoric acid concentration, pretreatment temperature, time, and ratio of textiles and phosphoric acid were thoroughly investigated. Results indicated the mentioned four factors had significant influences on sugar and polyester recovery. Almost complete polyester recovery was achieved by enhancing phosphoric acid concentration, temperature and pretreatment time or reducing the ratio of textiles and phosphoric acid. However, these behaviors decreased the sugar recovery seriously. 100% polyester recovery with a maximum sugar recovery of 79.2% was achieved at the optimized conditions (85% phosphoric acid, 50°C, 7h, and the ratio of 1:15). According to the technical and cost-benefit analysis, it was technically feasible and potentially profitable to recover polyester and sugar from waste textiles by phosphoric acid pretreatment.

  19. Methodology for detecting residual phosphoric acid in polybenzoxazole fibers.

    PubMed

    Park, Eun Su; Sieber, John; Guttman, Charles; Rice, Kirk; Flynn, Kathleen; Watson, Stephanie; Holmes, Gale

    2009-12-01

    Because of the premature failure of in-service soft-body armor containing the ballistic fiber poly[(benzo-[1,2-d:5,4-d']-benzoxazole-2,6-diyl)-1,4-phenylene] (PBO), the Office of Law Enforcement Standards (OLES) at the National Institute of Standards and Technology (NIST) initiated a research program to investigate the reasons for this failure and to develop testing methodologies and protocols to ensure that these types of failures do not reoccur. In a report that focused on the stability of the benzoxazole ring that is characteristic of PBO fibers, Holmes, G. A.; Rice, K.; Snyder, C. R. J. Mater. Sci. 2006, 41, 4105-4116, showed that the benzoxazole ring was susceptible to hydrolytic degradation under acid conditions. Because of the processing conditions for the fibers, it is suspected by many researchers that residual phosphoric acid may cause degradation of the benzoxazole ring resulting in a reduction of ballistic performance. Prior to this work, no definitive data have indicated the presence of phosphoric acid since the residual phosphorus is not easily extracted and the processed fibers are known to incorporate phosphorus containing processing aids. Methods to efficiently extract phosphorus from PBO are described in this article. Further, characterization determined that the majority of the extractable phosphorus in PBO was attributed to the octyldecyl phosphate processing aid with some phosphoric acid being detected. Analysis by matrix assisted laser desorption ionization of model PBO oligomers indicates that the nonextractable phosphorus is attached to the PBO polymer chain as a monoaryl phosphate ester. The response of model aryl phosphates to NaOH exposure indicates that monoaryl phosphate ester is stable to NaOH washes used in the manufacturing process to neutralize the phosphoric acid reaction medium and to extract residual phosphorus impurities. PMID:19899783

  20. Methodology for detecting residual phosphoric acid in polybenzoxazole fibers.

    PubMed

    Park, Eun Su; Sieber, John; Guttman, Charles; Rice, Kirk; Flynn, Kathleen; Watson, Stephanie; Holmes, Gale

    2009-12-01

    Because of the premature failure of in-service soft-body armor containing the ballistic fiber poly[(benzo-[1,2-d:5,4-d']-benzoxazole-2,6-diyl)-1,4-phenylene] (PBO), the Office of Law Enforcement Standards (OLES) at the National Institute of Standards and Technology (NIST) initiated a research program to investigate the reasons for this failure and to develop testing methodologies and protocols to ensure that these types of failures do not reoccur. In a report that focused on the stability of the benzoxazole ring that is characteristic of PBO fibers, Holmes, G. A.; Rice, K.; Snyder, C. R. J. Mater. Sci. 2006, 41, 4105-4116, showed that the benzoxazole ring was susceptible to hydrolytic degradation under acid conditions. Because of the processing conditions for the fibers, it is suspected by many researchers that residual phosphoric acid may cause degradation of the benzoxazole ring resulting in a reduction of ballistic performance. Prior to this work, no definitive data have indicated the presence of phosphoric acid since the residual phosphorus is not easily extracted and the processed fibers are known to incorporate phosphorus containing processing aids. Methods to efficiently extract phosphorus from PBO are described in this article. Further, characterization determined that the majority of the extractable phosphorus in PBO was attributed to the octyldecyl phosphate processing aid with some phosphoric acid being detected. Analysis by matrix assisted laser desorption ionization of model PBO oligomers indicates that the nonextractable phosphorus is attached to the PBO polymer chain as a monoaryl phosphate ester. The response of model aryl phosphates to NaOH exposure indicates that monoaryl phosphate ester is stable to NaOH washes used in the manufacturing process to neutralize the phosphoric acid reaction medium and to extract residual phosphorus impurities.

  1. Integral edge seals for phosphoric acid fuel cells

    DOEpatents

    Granata, Jr., Samuel J.; Woodle, Boyd M.; Dunyak, Thomas J.

    1992-01-01

    A phosphoric acid fuel cell having integral edge seals formed by an elastomer permeating an outer peripheral band contiguous with the outer peripheral edges of the cathode and anode assemblies and the matrix to form an integral edge seal which is reliable, easy to manufacture and has creep characteristics similar to the anode, cathode and matrix assemblies inboard of the seals to assure good electrical contact throughout the life of the fuel cell.

  2. Status of commercial phosphoric acid fuel cell system development

    NASA Technical Reports Server (NTRS)

    Warshay, M.; Prokopius, P. R.; Simons, S. N.; King, R. B.

    1981-01-01

    A review of the current commercial phosphoric acid fuel cell system development efforts is presented. In both the electric utility and on-site integrated energy system applications, reducing cost and increasing reliability are important. The barrier to the attainment of these goals has been materials. The differences in approach among the three major participants are their technological features, including electrodes, matrices, intercell cooling, bipolar/separator plates, electrolyte management, fuel selection and system design philosophy.

  3. 40 CFR 721.6200 - Fatty acid polyamine condensate, phosphoric acid ester salts.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Fatty acid polyamine condensate... New Uses for Specific Chemical Substances § 721.6200 Fatty acid polyamine condensate, phosphoric acid... substances identified as fatty acid polyamine condensate, phosphate ester salts (PMNs P-90-1984 and...

  4. Full scale phosphoric acid fuel cell stack technology development

    NASA Technical Reports Server (NTRS)

    Christner, L.; Faroque, M.

    1984-01-01

    The technology development for phosphoric acid fuel cells is summarized. The preparation, heat treatment, and characterization of carbon composites used as bipolar separator plates are described. Characterization included resistivity, porosity, and electrochemical corrosion. High density glassy carbon/graphite composites performed well in long-term fuel cell endurance tests. Platinum alloy cathode catalysts and low-loaded platinum electrodes were evaluated in 25 sq cm cells. Although the alloys displayed an initial improvement, some of this improvement diminished after a few thousand hours of testing. Low platinum loading (0.12 mg/sq cm anodes and 0.3 mg/sq cm cathodes) performed nearly as well as twice this loading. A selectively wetproofed anode backing paper was tested in a 5 by 15 inch three-cell stack. This material may provide for acid volume expansion, acid storage, and acid lateral distribution.

  5. Influence of pH-control in phosphoric acid treatment of titanium oxide and their powder properties

    SciTech Connect

    Onoda, Hiroaki Matsukura, Aki

    2015-06-15

    Highlights: • The photocatalytic activity was suppressed by phosphoric acid treatment. • The obtained pigment had small particles with sub-micrometer size. • By phosphoric acid treatment, the smoothness of samples improved. - Abstract: Titanium oxide that has the photocatalytic activity is used as a white pigment for cosmetics. A certain degree of sebum on the skin is decomposed by the ultraviolet radiation in sunlight. In this work, titanium oxide was shaken with phosphoric acid at various pH to synthesize a novel white pigment for cosmetics. Their chemical composition, powder properties, photocatalytic activity, color phase, and smoothness were studied. The obtained materials indicated XRD peaks of titanium oxide, however, these peak intensity became weak by phosphoric acid treatment. These samples without heating and heated at 100 °C included the small particles with sub-micrometer size. The photocatalytic activity of the obtained powders became weak by phosphoric acid treatment at pH 4 and 5 to protect the sebum on the skin.

  6. 40 CFR 721.10177 - Phosphoric acid, yttrium(3+) salt (1:1).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Phosphoric acid, yttrium(3+) salt (1:1... Specific Chemical Substances § 721.10177 Phosphoric acid, yttrium(3+) salt (1:1). (a) Chemical substance... acid, yttrium(3+) salt (1:1) (PMN P-04-153; CAS No. 13990-54-0) is subject to reporting under...

  7. 40 CFR 721.10177 - Phosphoric acid, yttrium(3+) salt (1:1).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Phosphoric acid, yttrium(3+) salt (1:1... Specific Chemical Substances § 721.10177 Phosphoric acid, yttrium(3+) salt (1:1). (a) Chemical substance... acid, yttrium(3+) salt (1:1) (PMN P-04-153; CAS No. 13990-54-0) is subject to reporting under...

  8. 40 CFR 721.10177 - Phosphoric acid, yttrium(3+) salt (1:1).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Phosphoric acid, yttrium(3+) salt (1:1... Specific Chemical Substances § 721.10177 Phosphoric acid, yttrium(3+) salt (1:1). (a) Chemical substance... acid, yttrium(3+) salt (1:1) (PMN P-04-153; CAS No. 13990-54-0) is subject to reporting under...

  9. 40 CFR 721.10177 - Phosphoric acid, yttrium(3+) salt (1:1).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Phosphoric acid, yttrium(3+) salt (1:1... Specific Chemical Substances § 721.10177 Phosphoric acid, yttrium(3+) salt (1:1). (a) Chemical substance... acid, yttrium(3+) salt (1:1) (PMN P-04-153; CAS No. 13990-54-0) is subject to reporting under...

  10. 40 CFR 721.10177 - Phosphoric acid, yttrium(3+) salt (1:1).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Phosphoric acid, yttrium(3+) salt (1:1... Specific Chemical Substances § 721.10177 Phosphoric acid, yttrium(3+) salt (1:1). (a) Chemical substance... acid, yttrium(3+) salt (1:1) (PMN P-04-153; CAS No. 13990-54-0) is subject to reporting under...

  11. Technology Development for Phosphoric Acid Fuel Cell Powerplant, Phase 2

    NASA Technical Reports Server (NTRS)

    Christner, L.

    1980-01-01

    The technology development for materials, cells, and reformers for on site integrated energy systems is described. The carbonization of 25 cu cm, 350 cu cm, and 1200 cu cm cell test hardware was accomplished and the performance of 25 cu cm fuel cells was improved. Electrochemical corrosion rates of graphite/phenolic resin composites in phosphoric acid were determined. Three cells (5 in by 15 in stacks) were operated for longer than 7000 hours. Specified endurance stacks completed a total of 4000 hours. An electrically heated reformer was tested and is to provide hydrogen for 23 cell fuel cell stack.

  12. Catalyst and electrode research for phosphoric acid fuel cells

    NASA Technical Reports Server (NTRS)

    Antoine, A. C.; King, R. B.

    1987-01-01

    An account is given of the development status of phosphoric acid fuel cells' high performance catalyst and electrode materials. Binary alloys have been identified which outperform the baseline platinum catalyst; it has also become apparent that pressurized operation is required to reach the desired efficiencies, calling in turn for the use of graphitized carbon blacks in the role of catalyst supports. Efforts to improve cell performance and reduce catalyst costs have led to the investigation of a class of organometallic cathode catalysts represented by the tetraazaannulenes, and a mixed catalyst which is a mixture of carbons catalyzed with an organometallic and a noble metal.

  13. Commercial phosphoric acid fuel cell system technology development

    NASA Technical Reports Server (NTRS)

    Prokopius, P. R.; Warshay, M.; Simons, S. N.; King, R. B.

    1979-01-01

    A review of the current commercial phosphoric acid fuel cell system technology development efforts is presented. In both the electric utility and on-site integrated energy system applications, reducing cost and increasing reliability are the technology drivers at this time. The longstanding barrier to the attainment of these goals, which manifests itself in a number of ways, has been materials. The differences in approach among the three major participants (United Technologies Corporation (UTC), Westinghouse Electric Corporation/Energy Research Corporation (ERC), and Engelhard Industries) and their unique technological features, including electrodes, matrices, intercell cooling, bipolar/separator plates, electrolyte management, fuel selection and system design philosophy are discussed.

  14. Assessment of the environmental aspects of the DOE phosphoric acid fuel cell program

    NASA Technical Reports Server (NTRS)

    Lundblad, H. L.; Cavagrotti, R. R.

    1983-01-01

    The likely facets of a nationwide phosphoric acid fuel cell (PAFC) power plant commercial system are described. The beneficial and adverse environmental impacts produced by the system are assessed. Eleven specific system activities are characterized and evaluated. Also included is a review of fuel cell technology and a description of DOE's National Fuel Cell Program. Based on current and reasonably foreseeable PAFC characteristics, no environmental or energy impact factor was identified that would significantly inhibit the commercialization of PAFC power plant technology.

  15. Technology development for phosphoric acid fuel cell powerplant, phase 2

    NASA Technical Reports Server (NTRS)

    Christner, L.

    1979-01-01

    Component development has resulted in routine molding of 12 in. by 17 in. bipolar plates with 80 percent acceptance. A 5 C per hour post-cure heating cycle for these plates was found to give blister free materials. Lowering the resin in a bipolar plate content from 32 percent to 22 percent decreases the resistivity more than 50 percent. Evaluation of the corrosion resistance of Novolak and Resol resins at 185 C in phosphoric acid indicates a slow etch. aerosol modified phenolics, however, decompose rapidly. Estimates of acid loss by the use of analytical expressions known as Margule, van Laar, and Wilson equations were not satisfactory. Experimental evaluation of the P4O10 vapor concentration of 103 wt percent acid at 191 C provided a value of 2 ppm. This value is based on a single experiment.

  16. 40 CFR 721.6200 - Fatty acid polyamine condensate, phosphoric acid ester salts.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ..., phosphoric acid ester salts. 721.6200 Section 721.6200 Protection of Environment ENVIRONMENTAL PROTECTION... ester salts. (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substances identified as fatty acid polyamine condensate, phosphate ester salts (PMNs P-90-1984 and...

  17. Nitric-phosphoric acid treatment of TRU wastes

    SciTech Connect

    Smith, J.R.; Pierce, R.A.; Sturcken, E.F.

    1993-09-30

    A general process is being developed for the treatment of solid TRU and hazardous organic waste. Experimental data indicates that 100 lb/hr of aliphatic organic (plastics) and 1,000 lb/hr of non-aliphatic organic compounds can be quantitatively oxidized in a 1,000 gallon reaction vessel. The process uses dilute nitric acid in a concentrated phosphoric acid media as the main oxidant for the organic compounds. Phosphoric acid allows oxidation at temperatures up to 200{degrees}C and is relatively non-corrosive on 304-L stainless steel, especially at room temperature. Many organic materials have been completely oxidized to CO{sub 2}, CO, and inorganic acids in a 0.1M HNO{sub 3}/14.8M H{sub 3}PO{sub 4} solution. Addition of 0.001M Pd{sup 2+} reduces the CO to near 1% of the released carbon gases. To accomplish complete oxidation the solution temperature must be maintained above 130--150{degrees}C. Organic materials quantitatively destroyed include neoprene, cellulose, EDTA, TBP, tartaric acid, and nitromethane. The oxidation is usually complete in a few hours for soluble organic materials. The oxidation rate for non-aliphatic organic solids is moderately fast and surface area dependent. Polyethylene is quantitatively oxidized in 1.0M HNO{sub 3}/13.8M H{sub 3}PO{sub 4} solution while contained in pressure vessels heated with microwave energy. This is probably due to the high concentrations of NO{sub 2}{center_dot} obtained in the reaction environment.

  18. Effects of ultrasonic fields in the phosphoric acid process

    NASA Technical Reports Server (NTRS)

    Kowalska, E.; Mizera, J.; Jakobiec, H.

    1974-01-01

    A process of apatite decomposition with sulfuric acid was studied under the influence of ultrasound in the phosphoric acid production process. The studies were carried out with and without ultrasonic fields in the reaction mixture, which resembled the mixing ratio used in technical production processes. Ultrasound with a frequency of 20 kHz and an intensity of 1 W/sq cm was used in the studies. A very favorable ultrasonic effect upon the degree of apatite decomposition was observed. The ultrasonic field affects the shape of byproduct gypsum crystals. In the H3PO4 production process without ultrasound, the byproduct gypsum crystallizes as long, thin needles which cause problems in filtration. In the trials involving the application of wound, gypsum crystallized in the form of small platelets possessing a favorable ratio of length to width.

  19. 21 CFR 175.260 - Partial phosphoric acid esters of polyester resins.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Partial phosphoric acid esters of polyester resins... of polyester resins. Partial phosphoric acid esters of polyester resins identified in this section... resins are prepared by the reaction of trimellitic anhydride with 2,2-dimethyl-1,3-propanediol...

  20. 40 CFR 721.6110 - Alkyldi(alkyloxyhydroxypropyl) derivative, phosphoric acid esters, potassium salts.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) derivative, phosphoric acid esters, potassium salts. (a) Chemical substance and significant new uses subject...) derivative, phosphoric acid esters, potassium salts. 721.6110 Section 721.6110 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF...

  1. 40 CFR 721.6110 - Alkyldi(alkyloxyhydroxypropyl) derivative, phosphoric acid esters, potassium salts.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...) derivative, phosphoric acid esters, potassium salts. (a) Chemical substance and significant new uses subject...) derivative, phosphoric acid esters, potassium salts. 721.6110 Section 721.6110 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF...

  2. 40 CFR 721.6110 - Alkyldi(alkyloxyhydroxypropyl) derivative, phosphoric acid esters, potassium salts.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...) derivative, phosphoric acid esters, potassium salts. (a) Chemical substance and significant new uses subject...) derivative, phosphoric acid esters, potassium salts. 721.6110 Section 721.6110 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF...

  3. Structural changes of oil palm empty fruit bunch (OPEFB) after fungal and phosphoric acid pretreatment.

    PubMed

    Isroi; Ishola, Mofoluwake M; Millati, Ria; Syamsiah, Siti; Cahyanto, Muhammad N; Niklasson, Claes; Taherzadeh, Mohammad J

    2012-01-01

    Oil palm empty fruit bunch (OPEFB) was pretreated using white-rot fungus Pleurotus floridanus, phosphoric acid or their combination, and the results were evaluated based on the biomass components, and its structural and morphological changes. The carbohydrate losses after fungal, phosphoric acid, and fungal followed by phosphoric acid pretreatments were 7.89%, 35.65%, and 33.77%, respectively. The pretreatments changed the hydrogen bonds of cellulose and linkages between lignin and carbohydrate, which is associated with crystallinity of cellulose of OPEFB. Lateral Order Index (LOI) of OPEFB with no pretreatment, with fungal, phosphoric acid, and fungal followed by phosphoric acid pretreatments were 2.77, 1.42, 0.67, and 0.60, respectively. Phosphoric acid pretreatment showed morphological changes of OPEFB, indicated by the damage of fibre structure into smaller particle size. The fungal-, phosphoric acid-, and fungal followed by phosphoric acid pretreatments have improved the digestibility of OPEFB's cellulose by 4, 6.3, and 7.4 folds, respectively. PMID:23247371

  4. 40 CFR 721.10140 - Phosphoric acid, tin (2+) salt (2:3).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Phosphoric acid, tin (2+) salt (2:3... Specific Chemical Substances § 721.10140 Phosphoric acid, tin (2+) salt (2:3). (a) Chemical substance and...+) salt (2:3) (PMN P-06-33, CAS No. 15578-32-2) is subject to reporting under this section for...

  5. 40 CFR 721.10140 - Phosphoric acid, tin (2+) salt (2:3).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Phosphoric acid, tin (2+) salt (2:3... Specific Chemical Substances § 721.10140 Phosphoric acid, tin (2+) salt (2:3). (a) Chemical substance and...+) salt (2:3) (PMN P-06-33, CAS No. 15578-32-2) is subject to reporting under this section for...

  6. 40 CFR 721.10140 - Phosphoric acid, tin (2+) salt (2:3).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Phosphoric acid, tin (2+) salt (2:3... Specific Chemical Substances § 721.10140 Phosphoric acid, tin (2+) salt (2:3). (a) Chemical substance and...+) salt (2:3) (PMN P-06-33, CAS No. 15578-32-2) is subject to reporting under this section for...

  7. 40 CFR 721.10140 - Phosphoric acid, tin (2+) salt (2:3).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Phosphoric acid, tin (2+) salt (2:3... Specific Chemical Substances § 721.10140 Phosphoric acid, tin (2+) salt (2:3). (a) Chemical substance and...+) salt (2:3) (PMN P-06-33, CAS No. 15578-32-2) is subject to reporting under this section for...

  8. 40 CFR 721.10140 - Phosphoric acid, tin (2+) salt (2:3).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Phosphoric acid, tin (2+) salt (2:3... Specific Chemical Substances § 721.10140 Phosphoric acid, tin (2+) salt (2:3). (a) Chemical substance and...+) salt (2:3) (PMN P-06-33, CAS No. 15578-32-2) is subject to reporting under this section for...

  9. Non-noble catalysts and catalyst supports for phosphoric acid fuel cells

    NASA Technical Reports Server (NTRS)

    Mcalister, A. J.

    1981-01-01

    Tungsten carbide, which is active for hydrogen oxidation, is CO tolerant and has a hexagonal structure is discussed. Titanium carbide is inactive and has a cubic structure. Four different samples of the cubic alloys W sub x-1Ti sub XC sub 1-y were found to be active and CO tolerant. When the activities of these cubic alloys are weighted by the reciprocal of the square to those of highly forms of WC. They offer important insight into the nature of the active sites on W-C anode catalysts for use in phosphoric acid fuel cells.

  10. Non-noble catalysts and catalyst supports for phosphoric acid fuel cells

    NASA Technical Reports Server (NTRS)

    Mcalister, A. J.

    1981-01-01

    Four different samples of the cubic alloys W sub x-1 Ti sub x C sub 1-y were prepared and found to be active and CO tolerant. When the activities of these cubic alloys were weighted by the reciprocal of the square of the W exchange, they displayed magnitudes and dependence on bulk C deficiency comparable to those of highly active forms of WC. It is concluded that they may offer important insight into the nature of the active sites on, and means for improving the performance of, W-C anode catalysts for use in phosphoric acid fuel cells.

  11. Non-noble catalysts and catalyst supports for phosphoric acid fuel cells

    NASA Technical Reports Server (NTRS)

    Mcalister, A. J.

    1980-01-01

    Tungsten carbide, which is known to be active for hydrogen oxidation and CO tolerant has a hexagonal structure. Titanium carbide is inactive and has a cubic structure. Four different samples of the cubic alloys Wx-1TixC were prepared and found to be active and CO tolerant. These alloys are of interest as possible phosphoric acid fuel cell catalysts. They also are of interest as opportunities to study the activity of W in a different crystalline environment and to correlate the activities of the surface sites with surface composition.

  12. 40 CFR 721.6100 - Phosphoric acid, C6-12-alkyl esters, compounds with 2-(dibutylamino) ethanol.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Phosphoric acid, C6-12-alkyl esters... Significant New Uses for Specific Chemical Substances § 721.6100 Phosphoric acid, C6-12-alkyl esters... reporting. (1) The chemical substances identified as phosphoric acid, C6-12-alkyl esters, compounds with...

  13. 40 CFR 721.6100 - Phosphoric acid, C6-12-alkyl esters, compounds with 2-(dibutylamino) ethanol.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Phosphoric acid, C6-12-alkyl esters... Significant New Uses for Specific Chemical Substances § 721.6100 Phosphoric acid, C6-12-alkyl esters... reporting. (1) The chemical substances identified as phosphoric acid, C6-12-alkyl esters, compounds with...

  14. 40 CFR 721.6100 - Phosphoric acid, C6-12-alkyl esters, compounds with 2-(dibutylamino) ethanol.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Phosphoric acid, C6-12-alkyl esters... Significant New Uses for Specific Chemical Substances § 721.6100 Phosphoric acid, C6-12-alkyl esters... reporting. (1) The chemical substances identified as phosphoric acid, C6-12-alkyl esters, compounds with...

  15. 40 CFR 721.6100 - Phosphoric acid, C6-12-alkyl esters, compounds with 2-(dibutylamino) ethanol.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Phosphoric acid, C6-12-alkyl esters... Significant New Uses for Specific Chemical Substances § 721.6100 Phosphoric acid, C6-12-alkyl esters... reporting. (1) The chemical substances identified as phosphoric acid, C6-12-alkyl esters, compounds with...

  16. 40 CFR 721.6100 - Phosphoric acid, C6-12-alkyl esters, compounds with 2-(dibutylamino) ethanol.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Phosphoric acid, C6-12-alkyl esters... Significant New Uses for Specific Chemical Substances § 721.6100 Phosphoric acid, C6-12-alkyl esters... reporting. (1) The chemical substances identified as phosphoric acid, C6-12-alkyl esters, compounds with...

  17. Technology development for phosphoric acid fuel cell powerplant, phase 2

    NASA Technical Reports Server (NTRS)

    Christner, L.

    1981-01-01

    The development of materials, cell components, and reformers for on site integrated energy systems is described. Progress includes: (1) heat-treatment of 25 sq cm, 350 sq cm and 1200 sq cm cell test hardware was accomplished. Performance of fuel cells is improved by using this material; (2) electrochemical and chemical corrosion rates of heat-treated and as-molded graphite/phenolic resin composites in phosphoric acid were determined; (3) three cell, 5 in. x 15 in. stacks operated for up to 10,000 hours and 12 in. x 17 in. five cell stacks were tested for 5,000 hours; (4) a three cell 5 in. x 15 in. stack with 0.12 mg Pt/sq cm anodes and 0.25 mg Pt/sq cm cathodes was operated for 4,500 hours; and (5) an ERC proprietary high bubble pressure matrix, MAT-1, was tested for up to 10,000 hours.

  18. Transmission electron microscopic examination of phosphoric acid fuel cell components

    NASA Technical Reports Server (NTRS)

    Pebler, A.

    1986-01-01

    Transmission electron microscopy (TEM) was used to physically characterize tested and untested phosphoric acid fuel cell (PAFC) components. Those examined included carbon-supported platinum catalysts, carbon backing paper, and Teflon-bonded catalyst layers at various stages of fabrication and after testing in pressurized PAFC's. Applicability of electron diffraction and electron energy loss spectroscopy for identifying the various phases was explored. The discussion focuses on the morphology and size distribution of platinum, the morphology and structural aspects of Teflon in catalyst layers, and the structural evidence of carbon corrosion. Reference is made to other physical characterization techniques where appropriate. A qualitative model of the catalyst layer that emerged from the TEM studies is presented.

  19. Organometallic catalysts for primary phosphoric acid fuel cells

    NASA Technical Reports Server (NTRS)

    Walsh, Fraser

    1987-01-01

    A continuing effort by the U.S. Department of Energy to improve the competitiveness of the phosphoric acid fuel cell by improving cell performance and/or reducing cell cost is discussed. Cathode improvement, both in performance and cost, available through the use of a class of organometallic cathode catalysts, the tetraazaannulenes (TAAs), was investigated. A new mixed catalyst was identified which provides improved cathode performance without the need for the use of a noble metal. This mixed catalyst was tested under load for 1000 hr. in full cell at 160 to 200 C in phosphoric acid H3PO4, and was shown to provide stable performance. The mixed catalyst contains an organometallic to catalyze electroreduction of oxygen to hydrogen peroxide and a metal to catalyze further electroreduction of the hydrogen peroxide to water. Cathodes containing an exemplar mixed catalyst (e.g., Co bisphenyl TAA/Mn) operate at approximately 650 mV vs DHE in 160 C, 85% H3PO4 with oxygen as reactant. In developing this mixed catalyst, a broad spectrum of TAAs were prepared, tested in half-cell and in a rotating ring-disk electrode system. TAAs found to facilitate the production of hydrogen peroxide in electroreduction were shown to be preferred TAAs for use in the mixed catalyst. Manganese (Mn) was identified as a preferred metal because it is capable of catalyzing hydrogen peroxide electroreduction, is lower in cost and is of less strategic importance than platinum, the cathode catalyst normally used in the fuel cell.

  20. Activated phosphors having matrices of yttrium-transition metal compound

    DOEpatents

    De Kalb, E.L.; Fassel, V.A.

    1975-07-01

    A method is described for preparing a phosphor composition containing a lanthanide activator element with a host matrix having a transition element as a major component. The host matrix is composed of certain rare earth phosphates or vanadates such as YPO$sub 4$ with a portion of the rare earth replaced with one or more of the transition elements. On x-ray or other electromagnetic excitation, trace lanthanide impurities or additives within the phosphor are spectrometrically determined from their characteristic luminescence. (auth)

  1. 40 CFR 721.6200 - Fatty acid polyamine condensate, phosphoric acid ester salts.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... ester salts. (a) Chemical substances and significant new uses subject to reporting. (1) The chemical..., phosphoric acid ester salts. 721.6200 Section 721.6200 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES...

  2. 40 CFR 721.6200 - Fatty acid polyamine condensate, phosphoric acid ester salts.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... ester salts. (a) Chemical substances and significant new uses subject to reporting. (1) The chemical..., phosphoric acid ester salts. 721.6200 Section 721.6200 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES...

  3. Method for separating mono- and di-octylphenyl phosphoric acid esters

    DOEpatents

    Arnold, Jr., Wesley D.

    1977-01-01

    A method for separating mono-octylphenyl phosphoric acid ester and di-octylphenyl phosphoric acid ester from a mixture thereof comprises reacting the ester mixture with a source of lithium or sodium ions to form a mixture of the phosphate salts; contacting the salt mixture with an organic solvent which causes the dioctylphenyl phosphate salt to be dissolved in the organic solvent phase and the mono-octylphenyl phosphate salt to exist in a solid phase; separating the phases; recovering the phosphate salts from their respective phases; and acidifying the recovered salts to form the original phosphoric acid esters.

  4. Rare earth activated yttrium aluminate phosphors with modulated luminescence.

    PubMed

    Muresan, L E; Popovici, E J; Perhaita, I; Indrea, E; Oro, J; Casan Pastor, N

    2016-06-01

    Yttrium aluminate (Y3 A5 O12 ) was doped with different rare earth ions (i.e. Gd(3+) , Ce(3+) , Eu(3+) and/or Tb(3+) ) in order to obtain phosphors (YAG:RE) with general formula,Y3-x-a Gdx REa Al5 O12 (x = 0; 1.485; 2.97 and a = 0.03). The synthesis of the phosphor samples was done using the simultaneous addition of reagents technique. This study reveals new aspects regarding the influence of different activator ions on the morpho-structural and luminescent characteristics of garnet type phosphor. All YAG:RE phosphors are well crystallized powders containing a cubic-Y3 Al5 O12 phase as major component along with monoclinic-Y4 Al2 O9 and orthorhombic-YAlO3 phases as the impurity. The crystallites dimensions of YAG:RE phosphors vary between 38 nm and 88 nm, while the unit cell slowly increase as the ionic radius of the activator increases. Under UV excitation, YAG:Ce exhibits yellow emission due to electron transition in Ce(3+) from the 5d level to the ground state levels ((2) F5/2 , (2) F7/2 ). The emission intensity of Ce(3+) is enhanced in the presence of the Tb(3+) ions and is decreased in the presence of Eu(3+) ions due to some radiative or non-radiative processes that take place between activator ions. By varying the rare earth ions, the emission colour can be modulated from green to white and red. Copyright © 2015 John Wiley & Sons, Ltd. PMID:26553167

  5. Wet Chemical Oxidation of Organic Waste Using Nitric-Phosphoric Acid Technology

    SciTech Connect

    Pierce, R.A.

    1998-10-06

    Experimental progress has been made in a wide range of areas which support the continued development of the nitric-phosphoric acid oxidation process for combustible, solid organic wastes. An improved understanding of the overall process operation has been obtained, acid recovery and recycle systems have been studied, safety issues have been addressed, two potential final waste forms have been tested, preliminary mass flow diagrams have been prepared, and process flowsheets have been developed. The flowsheet developed is essentially a closed-loop system which addresses all of the internally generated waste streams. The combined activities aim to provide the basis for building and testing a 250-400 liter pilot-scale unit. Variations of the process now must be evaluated in order to address the needs of the primary customer, SRS Solid Waste Management. The customer is interested in treating job control waste contaminated with Pu-238 for shipment to WIPP. As a result, variations for feed preparation, acid recycle, and final form manufacturing must be considered to provide for simpler processing to accommodate operations in high radiation and contamination environments. The purpose of this program is to demonstrate a nitric-phosphoric acid destruction technology which can treat a heterogeneous waste by oxidizing the solid and liquid organic compounds while decontaminating noncombustible items.

  6. 21 CFR 175.260 - Partial phosphoric acid esters of polyester resins.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... resins are prepared by the reaction of trimellitic anhydride with 2,2-dimethyl-1,3-propanediol followed by reaction of the resin thus produced with phosphoric acid anhydride to produce a resin having...

  7. Molten Carbonate and Phosphoric Acid Stationary Fuel Cells: Overview and Gap Analysis

    SciTech Connect

    Remick, R.; Wheeler, D.

    2010-09-01

    This report describes the technical and cost gap analysis performed to identify pathways for reducing the costs of molten carbonate fuel cell (MCFC) and phosphoric acid fuel cell (PAFC) stationary fuel cell power plants.

  8. Dry compliant seal for phosphoric acid fuel cell

    DOEpatents

    Granata, Jr., Samuel J.; Woodle, Boyd M.

    1990-01-01

    A dry compliant overlapping seal for a phosphoric acid fuel cell preformed f non-compliant Teflon to make an anode seal frame that encircles an anode assembly, a cathode seal frame that encircles a cathode assembly and a compliant seal frame made of expanded Teflon, generally encircling a matrix assembly. Each frame has a thickness selected to accommodate various tolerances of the fuel cell elements and are either bonded to one of the other frames or to a bipolar or end plate. One of the non-compliant frames is wider than the other frames forming an overlap of the matrix over the wider seal frame, which cooperates with electrolyte permeating the matrix to form a wet seal within the fuel cell that prevents process gases from intermixing at the periphery of the fuel cell and a dry seal surrounding the cell to keep electrolyte from the periphery thereof. The frames may be made in one piece, in L-shaped portions or in strips and have an outer perimeter which registers with the outer perimeter of bipolar or end plates to form surfaces upon which flanges of pan shaped, gas manifolds can be sealed.

  9. Combined cycle phosphoric acid fuel cell electric power system

    SciTech Connect

    Mollot, D.J.; Micheli, P.L.

    1995-12-31

    By arranging two or more electric power generation cycles in series, combined cycle systems are able to produce electric power more efficiently than conventional single cycle plants. The high fuel to electricity conversion efficiency results in lower plant operating costs, better environmental performance, and in some cases even lower capital costs. Despite these advantages, combined cycle systems for the 1 - 10 megawatt (MW) industrial market are rare. This paper presents a low noise, low (oxides of nitrogen) NOx, combined cycle alternative for the small industrial user. By combining a commercially available phosphoric acid fuel cell (PAFC) with a low-temperature Rankine cycle (similar to those used in geothermal applications), electric conversion efficiencies between 45 and 47 percent are predicted. While the simple cycle PAFC is competitive on a cost of energy basis with gas turbines and diesel generators in the 1 to 2 MW market, the combined cycle PAFC is competitive, on a cost of energy basis, with simple cycle diesel generators in the 4 to 25 MW market. In addition, the efficiency and low-temperature operation of the combined cycle PAFC results in a significant reduction in carbon dioxide emissions with NO{sub x} concentration on the order of 1 parts per million (per weight) (ppmw).

  10. Advanced water-cooled phosphoric acid fuel cell development

    SciTech Connect

    Not Available

    1992-09-01

    This program was conducted to improve the performance and minimize the cost of existing water-cooled phosphoric acid fuel cell stacks for electric utility and on-site applications. The goals for the electric utility stack technology were a power density of at least 175 watts per square foot over a 40,000-hour useful life and a projected one-of-a-kind, full-scale manufactured cost of less than $400 per kilowatt. The program adapted the existing on-site Configuration-B cell design to electric utility operating conditions and introduced additional new design features. Task 1 consisted of the conceptual design of a full-scale electric utility cell stack that meets program objectives. The conceptual design was updated to incorporate the results of material and process developments in Tasks 2 and 3, as well as results of stack tests conducted in Task 6. Tasks 2 and 3 developed the materials and processes required to fabricate the components that meet the program objectives. The design of the small area and 10-ft{sup 2} stacks was conducted in Task 4. Fabrication and assembly of the short stacks were conducted in Task 5 and subsequent tests were conducted in Task 6. The management and reporting functions of Task 7 provided DOE/METC with program visibility through required documentation and program reviews. This report describes the cell design and development effort that was conducted to demonstrate, by subscale stack test, the technical achievements made toward the above program objectives.

  11. Nitrosyl induces phosphorous-acid dissociation in ruthenium(II).

    PubMed

    Truzzi, Daniela Ramos; Ferreira, Antonio Gilberto; da Silva, Sebastião Claudino; Castellano, Eduardo Ernesto; Lima, Francisco das Chagas Alves; Franco, Douglas Wagner

    2011-12-28

    The trans-[Ru(NO)(NH(3))(4)(P(OH)(3))]Cl(3) complex was synthesized by reacting [Ru(H(2)O)(NH(3))(5)](2+) with H(3)PO(3) and characterized by spectroscopic ((31)P-NMR, δ = 68 ppm) and spectrophotometric techniques (λ = 525 nm, ε = 20 L mol(-1) cm(-1); λ = 319 nm, ε = 773 L mol(-1) cm(-1); λ = 241 nm, ε = 1385 L mol(-1) cm(-1); ν(NO(+)) = 1879 cm(-1)). A pK(a) of 0.74 was determined from infrared measurements as a function of pH for the reaction: trans-[Ru(NO)(NH(3))(4)(P(OH)(3))](3+) + H(2)O ⇌ trans-[Ru(NO)(NH(3))(4)(P(O(-))(OH)(2))](2+) + H(3)O(+). According to (31)P-NMR, IR, UV-vis, cyclic voltammetry and ab initio calculation data, upon deprotonation, trans-[Ru(NO)(NH(3))(4)(P(OH)(3))](3+) yields the O-bonded linkage isomer trans- [Ru(NO)(NH(3))(4)(OP(OH)(2))](2+), then the trans-[Ru(NO)(NH(3))(4)(OP(H)(OH)(2))](3+) decays to give the final products H(3)PO(3) and trans-[Ru(NO)(NH(3))(4)(H(2)O)](3+). The dissociation of phosphorous acid from the [Ru(NO)(NH(3))(4)](3+) moiety is pH dependent (k(obs) = 2.1 × 10(-4) s(-1) at pH 3.0, 25 °C). PMID:22027926

  12. Non-aqueous gel polymer electrolyte with phosphoric acid ester and its application for quasi solid-state supercapacitors

    NASA Astrophysics Data System (ADS)

    Łatoszyńska, Anna A.; Żukowska, Grażyna Zofia; Rutkowska, Iwona A.; Taberna, Pierre-Louis; Simon, Patrice; Kulesza, Pawel J.; Wieczorek, Władysław

    2015-01-01

    A mechanically-stable non-aqueous proton-conducting gel polymer electrolyte that is based on methacrylate monomers, is considered here for application in solid-state type supercapacitors. An electrochemical cell using activated carbon as active materials and the new gel polymer electrolyte has been characterized at room temperature using cyclic voltammetry, galvanostatic charge-discharge cycle tests as well as impedance spectroscopy. The use of phosphoric acid ester (instead of phosphoric acid) as a proton donor has led to an increase of both the operation voltage window (up to 1.3 V) and the electrolyte ionic conductivity (on the level of an order of magnitude). The resulting double layer capacitance of the microporous activated carbon was found to be as high as 120 F g-1; even more important, the supercapacitor utilizing non-aqueous proton-conducting gel polymer electrolyte is well-behaved in the wide temperature range (namely, from -40 to 80 °C).

  13. Behaviour and fluxes of natural radionuclides in the production process of a phosphoric acid plant.

    PubMed

    Bolívar, J P; Martín, J E; García-Tenorio, R; Pérez-Moreno, J P; Mas, J L

    2009-02-01

    In recent years there has been an increasing awareness of the occupational and public hazards of the radiological impact of non-nuclear industries which process materials containing naturally occurring radionuclides. These include the industries devoted to the production of phosphoric acid by treating sedimentary phosphate rocks enriched in radionuclides from the uranium series. With the aim of evaluating the radiological impact of a phosphoric acid factory located in the south-western Spain, the distribution and levels of radionuclides in the materials involved in its production process have been analysed. In this way, it is possible to asses the flows of radionuclides at each step and to locate those points where a possible radionuclide accumulation could be produced. A set of samples collected along the whole production process were analysed to determine their radionuclide content by both alpha-particle and gamma spectrometry techniques. The radionuclide fractionation steps and enrichment sources have been located, allowing the establishment of their mass (activity) balances per year.

  14. Production of monosaccharides from napier grass by hydrothermal process with phosphoric acid.

    PubMed

    Takata, Eri; Tsutsumi, Ken; Tsutsumi, Yuji; Tabata, Kenji

    2013-09-01

    The production of monosaccharides from napier grass was investigated in the presence of acid catalysts using the hydrothermal process. When the napier grass was treated with 3 wt.% phosphoric acid at 160°C for 15min, the xylose yield reached 10.3 wt.%, corresponding to 72.0% of the xylan in it, whereas glucose was hardly obtained. A combined process was then conducted using an 85 wt.% phosphoric acid treatment at 60 °C for 1h followed by a hydrothermal treatment with 3 wt.% phosphoric acid. In the initial treatment with concentrated phosphoric acid the most of xylan was hydrolyzed to xylose, and the crystalline cellulose was converted to its amorphous form. The hydrolysis of cellulose to glucose was significantly enhanced during the following hydrothermal process with 3 wt.% phosphoric acid at 200 °C for 8 min. Consequently, 77.2% yield of xylose and 50.0% yield of glucose were obtained from the combined process.

  15. Rare earth elements recycling from waste phosphor by dual hydrochloric acid dissolution.

    PubMed

    Liu, Hu; Zhang, Shengen; Pan, Dean; Tian, Jianjun; Yang, Min; Wu, Maolin; Volinsky, Alex A

    2014-05-15

    This paper is a comparative study of recycling rare earth elements from waste phosphor, which focuses on the leaching rate and the technical principle. The traditional and dual dissolution by hydrochloric acid (DHA) methods were compared. The method of dual dissolution by hydrochloric acid has been developed. The Red rare earth phosphor (Y0.95Eu0.05)2O3 in waste phosphor is dissolved during the first step of acid leaching, while the Green phosphor (Ce0.67Tb0.33MgAl11O19) and the Blue phosphor (Ba0.9Eu0.1MgAl10O17) mixed with caustic soda are obtained by alkali sintering. The excess caustic soda and NaAlO2 are removed by washing. The insoluble matter is leached by the hydrochloric acid, followed by solvent extraction and precipitation (the DHA method). In comparison, the total leaching rate of the rare earth elements was 94.6% by DHA, which is much higher than 42.08% achieved by the traditional method. The leaching rate of Y, Eu, Ce and Tb reached 94.6%, 99.05%, 71.45%, and 76.22%, respectively. DHA can decrease the consumption of chemicals and energy. The suggested DHA method is feasible for industrial applications.

  16. Evaluating EDTA as a substitute for phosphoric acid-etching of enamel and dentin.

    PubMed

    Imbery, Terence A; Kennedy, Matthew; Janus, Charles; Moon, Peter C

    2012-01-01

    Matrix metalloproteinases (MMPs) are proteolytic enzymes released when dentin is acid-etched. The enzymes are capable of destroying unprotected collagen fibrils that are not encapsulated by the dentin adhesive. Chlorhexidine applied after etching inhibits the activation of released MMPs, whereas neutral ethylenediamine tetra-acetic acid (EDTA) prevents the release of MMPs. The purpose of this study was to determine if conditioning enamel and dentin with EDTA can be a substitute for treating acid-etching enamel and dentin with chlorhexidine. A column of composite resin was bonded to enamel and dentin after conditioning. Shear bond strengths were evaluated after 48 hours and after accelerated aging for three hours in 12% sodium hypochlorite. Shear bond strengths ranged from 15.6 MP a for accelerated aged EDTA enamel specimens to 26.8 MPa for dentin conditioned with EDTA and tested after 48 hours. A three-way ANOVA and a Tukey HSD test found statistically significant differences among the eight groups and the three independent variables (P < 0.05). EDTA was successfully substituted for phosphoric acid-etched enamel and dentin treated with chlorhexidine. Interactions of conditioning agent and aging were significant for dentin but not for enamel. In an effort to reduce the detrimental effects of MMPs, conditioning enamel and dentin with EDTA is an alternative to treating acid-etched dentin and enamel with chlorhexidine.

  17. Preparation and evaluation of advanced electrocatalysts for phosphoric acid fuel cells

    NASA Technical Reports Server (NTRS)

    Stonehart, P.; Baris, J.; Pagliaro, P.

    1980-01-01

    Results are presented for hydrogen oxidation and hydrogen oxidation poisoned by carbon monoxide at levels between 0 and 30%. Due to the high activities that are now being observed for our platinum based electrocatalysts, the hydrogen concentrations were reduced to 10% levels in the gas supplies. Perturbation techniques were used to determine that a mechanism for the efficient operation of our porous gas diffusion electrodes is diffusion of the carbon monoxide out of the electrode structure through the electrolyte film on the electro-catalyst. A survey of the literature on platinum group materials (PGM) was carried out so that an identification of successful electrocatalysts could be made. Two PGM electrocatalysts were prepared and performance data for hydrogen oxidation in hot phosphoric acid in the presence of high carbon monoxide concentrations showed that they matched the best platinum on carbon electrocatalysts but with an electrocatalyst cost that was half of the platinum catalyst cost.

  18. Optimizing ethanol and methane production from steam-pretreated, phosphoric acid-impregnated corn stover.

    PubMed

    Bondesson, Pia-Maria; Dupuy, Aurélie; Galbe, Mats; Zacchi, Guido

    2015-02-01

    Pretreatment is of vital importance in the production of ethanol and methane from agricultural residues. In this study, the effects of steam pretreatment with phosphoric acid on enzymatic hydrolysis (EH), simultaneous saccharification and fermentation (SSF), anaerobic digestion (AD) and the total energy output at three different temperatures were investigated. The effect of separating the solids for SSF and the liquid for AD was also studied and compared with using the whole slurry first in SSF and then in AD. Furthermore, the phosphoric acid was compared to previous studies using sulphuric acid or no catalyst. Using phosphoric acid resulted in higher yields than when no catalyst was used. However, compared with sulphuric acid, an improved yield was only seen with phosphoric acid in the case of EH. The higher pretreatment temperatures (200 and 210 °C) resulted in the highest yields after EH and SSF, while the highest methane yield was obtained with the lower pretreatment temperature (190 °C). The highest yield in terms of total energy recovery (78 %) was obtained after pretreatment at 190 °C, but a pretreatment temperature of 200 °C is, however, the best alternative since fewer steps are required (whole slurry in SSF and then in AD) and high product yields were obtained (76 %).

  19. Preliminary study on preparation of BCNO phosphor particles using citric acid as carbon source

    SciTech Connect

    Nuryadin, Bebeh W.; Pratiwi, Tripuspita; Faryuni, Irfana D.; Iskandar, Ferry Abdullah, Mikrajuddin; Khairurrijal; Ogi, Takashi; Okuyama, Kikuo

    2015-04-16

    A citric acid was used as a carbon source in the preparation of boron carbon oxy-nitride (BCNO) phosphor particles by a facile process. The preparation process was conducted at relatively low temperature 750 °C and at ambient pressure. The prepared BCNO phosphors showed a high photoluminescence (PL) performance at peak emission wavelength of 470 nm under excitation by a UV light 365 nm. The effects of carbon/boron and nitrogen/boron molar ratios on the PL properties were also investigated. The result showed that the emission spectra with a wavelength peak ranging from 444 nm to 496 nm can be obtained by varying carbon/boron ratios from 0.1 to 0.9. In addition, the observations showed that the BCNO phosphor material has two excitation peaks located at the 365 nm (UV) and 420 nm (blue). Based on these observations, we believe that the citric acid derived BCNO phosphor particles can be a promising inexpensive material for phosphor conversion-based white LED.

  20. Fructo-oligosaccharide production from inulin through partial citric or phosphoric acid hydrolyses.

    PubMed

    Fontana, José Domingos; Grzybowski, Adelia; Tiboni, Marcela; Passos, Maurício

    2011-11-01

    Purified inulin from Dahlia tubers was partially hydrolyzed to form fructo-oligosaccharides by using citric or phosphoric acids (pH, 2.0-2.5) as mild acid catalysts. The ideal kinetic conditions to ensure a high yield of fructo-oligosaccharides relative to free fructose were a temperature range of 85°C-95°C, a hydrolysis time of 15-25 minutes, and a catalyst pH of 2.5. At the higher temperature and the longest hydrolysis time, an inversion of the product ratio occurred. Under these conditions, co-generation of hydroxymethylfurfural occurred, and it was eliminated by activated charcoal. Unlike in classic hydrolysis with hydrochloric or sulfuric acid, deionization of the actual hydrolysates was not necessary because the catalyst neutralization with common bases results in the formation of co-nutrients with alternative uses as foods or fermentation substrates. These whole hydrolysates can be advantageously added as nutraceuticals to carbonated beverages and acidic foods, such as soft drinks and yogurts. PMID:21663491

  1. Conversion of waste cellulose to ethanol. Phase 2: Reaction kinetics with phosphoric acid

    NASA Astrophysics Data System (ADS)

    Moeller, M. B.; Isbell, R. E.

    1982-05-01

    Waste cellulosic material can be hydrolyzed in dilute acid solution to produce fermentable sugars which can then be converted into ethanol. A laboratory investigation was made of the feasibility of using phosphoric acid as the hydrolysis catalyst. The hydrolysis reaction with phosphoric acid solutions was compared with the reaction employing the more conventional dilute sulfuric acid catalyst. The purpose of this research was to examine the hydrolysis step in a proposed process for the conversion of cellulose (from wood, newspapers, municipal solid waste, or other sources) into ethanol - by which a potentially valuable co-product, DICAL (dicalcium phosphate), might be made and sold with or without the lignin content as a fertilizer. The pertinent reaction kinetics for the acid catalyzed production of glucose from cellulose consists of consecutive, pseudo-first order reactions.

  2. 21 CFR 175.260 - Partial phosphoric acid esters of polyester resins.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Partial phosphoric acid esters of polyester resins. 175.260 Section 175.260 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) INDIRECT FOOD ADDITIVES: ADHESIVES...

  3. 21 CFR 175.260 - Partial phosphoric acid esters of polyester resins.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Partial phosphoric acid esters of polyester resins. 175.260 Section 175.260 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) INDIRECT FOOD ADDITIVES: ADHESIVES AND COMPONENTS OF COATINGS Substances for Use...

  4. 21 CFR 175.260 - Partial phosphoric acid esters of polyester resins.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Partial phosphoric acid esters of polyester resins. 175.260 Section 175.260 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) INDIRECT FOOD ADDITIVES: ADHESIVES...

  5. Survey on aging on electrodes and electrocatalysts in phosphoric acid fuel cells

    NASA Technical Reports Server (NTRS)

    Stonehart, P.; Hochmuth, J.

    1981-01-01

    The processes which contribute to the decay in performance of electrodes used in phosphoric acid fuel cell systems are discussed. Loss of catalytic surface area, corrosion of the carbon support, electrode structure degradation, electrolyte degradation, and impurities in the reactant streams are identified as the major areas for concern.

  6. Tuning transport selectivity of ionic species by phosphoric acid gradient in positively charged nanochannel membranes.

    PubMed

    Yang, Meng; Yang, Xiaohai; Wang, Kemin; Wang, Qing; Fan, Xin; Liu, Wei; Liu, Xizhen; Liu, Jianbo; Huang, Jin

    2015-02-01

    The transport of ionic species through a nanochannel plays important roles in fundamental research and practical applications of the nanofluidic device. Here, we demonstrated that ionic transport selectivity of a positively charged nanochannel membrane can be tuned under a phosphoric acid gradient. When phosphoric acid solution and analyte solution were connected by the positively charged nanochannel membrane, the faster-moving analyte through the positively charged nanochannel membrane was the positively charged dye (methylviologen, MV(2+)) instead of the negatively charged dye (1,5-naphthalene disulfonate, NDS(2-)). In other words, a reversed ion selectivity of the nanochannel membranes can be found. It can be explained as a result of the combination of diffusion, induced electroosmosis, and induced electrophoresis. In addition, the influencing factors of transport selectivity, including concentration of phosphoric acid, penetration time, and volume of feed solution, were also investigated. The results showed that the transport selectivity can further be tuned by adjusting these factors. As a method of tuning ionic transport selectivity by establishing phosphoric acid gradient, it will be conducive to improving the separation of ionic species. PMID:25557761

  7. Modification of vital wheat gluten with phosphoric acid to produce high free-solution capacity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wheat gluten reacts with phosphoric acid to produce natural superabsorbent gels. The gel properties are defined by Fourier Transform Infra-red (FTIR) spectroscopy, 2-dimensional gel electrophoresis (2DE), and uptake of water, salt solutions, and aqueous ethanol. Temperatures above 120'C and dry cond...

  8. Current legal and institutional issues in the commercialization of phosphoric acid fuel cells

    NASA Technical Reports Server (NTRS)

    Nimmons, J. T.; Sheehy, K. D.; Singer, J. R.; Gardner, T. C.

    1982-01-01

    Legal and institutional factors affecting the development and commercial diffusion of phosphoric acid fuel cells are assessed. Issues for future research and action are suggested. Perceived barriers and potential opportunities for fuel cells in central and dispersed utility operations and on-site applications are reviewed, as well as the general concept of commercialization as applied to emerging energy technologies.

  9. Manual of phosphoric acid fuel cell power plant cost model and computer program

    NASA Technical Reports Server (NTRS)

    Lu, C. Y.; Alkasab, K. A.

    1984-01-01

    Cost analysis of phosphoric acid fuel cell power plant includes two parts: a method for estimation of system capital costs, and an economic analysis which determines the levelized annual cost of operating the system used in the capital cost estimation. A FORTRAN computer has been developed for this cost analysis.

  10. Modification of vital wheat gluten with phosphoric acid to produce high free solution capacity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wheat gluten reacts with phosphoric acid in the presence of urea to produce natural superabsorbent gels. Fourier Transform Infra-red (FT-IR) spectroscopy and two-dimensional gel electrophoresis (2DE) reveal chemical changes from the reaction. Temperatures above 120°C and dry conditions create the op...

  11. Phosphoric acid fuel cell power plant system performance model and computer program

    NASA Technical Reports Server (NTRS)

    Alkasab, K. A.; Lu, C. Y.

    1984-01-01

    A FORTRAN computer program was developed for analyzing the performance of phosphoric acid fuel cell power plant systems. Energy mass and electrochemical analysis in the reformer, the shaft converters, the heat exchangers, and the fuel cell stack were combined to develop a mathematical model for the power plant for both atmospheric and pressurized conditions, and for several commercial fuels.

  12. 40 CFR 721.10505 - Phosphoric acid, mixed mono- and diesters with 2-ethyl-1-hexanol and polyethylene glycol mono-C12...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Phosphoric acid, mixed mono- and... Phosphoric acid, mixed mono- and diesters with 2-ethyl-1-hexanol and polyethylene glycol mono-C12-16-alkyl... identified as phosphoric acid, mixed mono- and diesters with 2-ethyl-1-hexanol and polyethylene glycol...

  13. 40 CFR 721.10505 - Phosphoric acid, mixed mono- and diesters with 2-ethyl-1-hexanol and polyethylene glycol mono-C12...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Phosphoric acid, mixed mono- and... Phosphoric acid, mixed mono- and diesters with 2-ethyl-1-hexanol and polyethylene glycol mono-C12-16-alkyl... identified as phosphoric acid, mixed mono- and diesters with 2-ethyl-1-hexanol and polyethylene glycol...

  14. 40 CFR 721.6120 - Phosphoric acid, 1,2-eth-a-ne-diyl tet-ra-kis(2-chloro-1-meth-yl-ethyl) ester.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Phosphoric acid, 1,2-eth-a-ne-diyl tet... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.6120 Phosphoric acid, 1,2-eth-a-ne... subject to reporting. (1) The chemical substance identified as phosphoric acid, 1,2-ethanediyl...

  15. 40 CFR 721.6120 - Phosphoric acid, 1,2-eth-a-ne-diyl tet-ra-kis(2-chloro-1-meth-yl-ethyl) ester.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Phosphoric acid, 1,2-eth-a-ne-diyl tet... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.6120 Phosphoric acid, 1,2-eth-a-ne... subject to reporting. (1) The chemical substance identified as phosphoric acid, 1,2-ethanediyl...

  16. 40 CFR 721.6120 - Phosphoric acid, 1,2-eth-a-ne-diyl tet-ra-kis(2-chloro-1-meth-yl-ethyl) ester.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Phosphoric acid, 1,2-eth-a-ne-diyl tet... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.6120 Phosphoric acid, 1,2-eth-a-ne... subject to reporting. (1) The chemical substance identified as phosphoric acid, 1,2-ethanediyl...

  17. Activation of carboxylic acids in asymmetric organocatalysis.

    PubMed

    Monaco, Mattia Riccardo; Poladura, Belén; Diaz de Los Bernardos, Miriam; Leutzsch, Markus; Goddard, Richard; List, Benjamin

    2014-07-01

    Organocatalysis, catalysis using small organic molecules, has recently evolved into a general approach for asymmetric synthesis, complementing both metal catalysis and biocatalysis. Its success relies to a large extent upon the introduction of novel and generic activation modes. Remarkably though, while carboxylic acids have been used as catalyst directing groups in supramolecular transition-metal catalysis, a general and well-defined activation mode for this useful and abundant substance class is still lacking. Herein we propose the heterodimeric association of carboxylic acids with chiral phosphoric acid catalysts as a new activation principle for organocatalysis. This self-assembly increases both the acidity of the phosphoric acid catalyst and the reactivity of the carboxylic acid. To illustrate this principle, we apply our concept in a general and highly enantioselective catalytic aziridine-opening reaction with carboxylic acids as nucleophiles.

  18. Phosphoric acid distribution and its impact on the performance of polybenzimidazole membranes

    NASA Astrophysics Data System (ADS)

    Mack, Florian; Heissler, Stefan; Laukenmann, Ruben; Zeis, Roswitha

    2014-12-01

    Phosphoric acid doped polybenzimidazole (PBI) is the most common membrane material for high-temperature polymer electrolyte membrane fuel cells (HT-PEMFC). The PBI membrane is usually doped by immersion in hot phosphoric acid. Immersion time and acid temperature affect the doping level of the membrane. In this work we studied the influence of doping time and temperature on the ex-situ and in-situ proton conductivities of poly (2, 5-benzimidazole) (AB-PBI) membranes as well as the fuel cell performance. Confocal Raman microscopy was employed to spatially resolve the acid distribution within the AB-PBI membranes. Therefore the interactions between the basic nitrogen-sides of the AB-PBI polymer and the phosphoric acid protons were investigated. We found that membranes with a 6 h doping time had significantly higher proton conductivity than those doped for only 3 h. In terms of absolute acid up-take, however, the difference was rather small. This result shows that the doping level alone does not define the conductivity of the membrane. The conductivity is also influenced by the micro acid distribution within the membrane. Highest membrane conductivity and fuel cell performance with fumapem AM cross-linked membranes were achieved with a doping time of 6 h and a doping temperature of 120 °C.

  19. Acid properties of solid acid catalysts characterized by solid-state 31P NMR of adsorbed phosphorous probe molecules.

    PubMed

    Zheng, Anmin; Huang, Shing-Jong; Liu, Shang-Bin; Deng, Feng

    2011-09-01

    A brief review is presented on acidity characterization of solid acid catalysts by means of solid-state phosphor-31 magic-angle-spinning nuclear magnetic resonance ((31)P MAS NMR) spectroscopy using phosphor-containing molecules as probes. It is emphasized that such a simple approach using (31)P MAS NMR of adsorbed phosphorous probe molecules, namely trimethylphosphine (TMP) and trialkylphosphine oxides (R(3)PO), represents a unique technique in providing detailed qualitative and quantitative features, viz. type, strength, distribution, and concentration of acid sites in solid acid catalysts. In particular, it will be shown that when applied with a proper choice of probe molecules with varied sizes and results obtained from elemental analysis, the amounts and locations (intracrystalline vs. extracrystalline) of different types (Brønsted vs. Lewis) of acid sites may be determined. In addition, by incorporating the NMR results with that obtained from theoretical density functional theory (DFT) calculations, correlations between the (31)P chemical shifts (δ(31)P) and acidic strengths of Brønsted and Lewis acid sites may also be derived, facilitating a suitable acidity scale for solid acid catalysts.

  20. Determination of polyfluoroalkyl phosphoric acid diesters, perfluoroalkyl phosphonic acids, perfluoroalkyl phosphinic acids, perfluoroalkyl carboxylic acids, and perfluoroalkane sulfonic acids in lake trout from the Great Lakes region.

    PubMed

    Guo, Rui; Reiner, Eric J; Bhavsar, Satyendra P; Helm, Paul A; Mabury, Scott A; Braekevelt, Eric; Tittlemier, Sheryl A

    2012-11-01

    A comprehensive method to extract perfluoroalkyl carboxylic acids, perfluoroalkane sulfonic acids, perfluoroalkyl phosphonic acids, perfluoroalkyl phosphinic acids, and polyfluoroalkyl phosphoric acid diesters simultaneously from fish samples has been developed. The recoveries of target compounds ranged from 78 % to 121 %. The new method was used to analyze lake trout (Salvelinus namaycush) from the Great Lakes region. The results showed that the total perfluoroalkane sulfonate concentrations ranged from 0.1 to 145 ng/g (wet weight) with perfluorooctane sulfonate (PFOS) as the dominant contaminant. Concentrations in fish between lakes were in the order of Lakes Ontario ≈ Erie > Huron > Superior ≈ Nipigon. The total perfluoroalkyl carboxylic acid concentrations ranged from 0.2 to 18.2 ng/g wet weight. The aggregate mean perfluorooctanoic acid (PFOA) concentration in fish across all lakes was 0.045 ± 0.023 ng/g. Mean concentrations of PFOA were not significantly different (p > 0.1) among the five lakes. Perfluoroalkyl phosphinic acids were detected in lake trout from Lake Ontario, Lake Erie, and Lake Huron with concentration ranging from non-detect (ND) to 0.032 ng/g. Polyfluoroalkyl phosphoric acid diesters were detected only in lake trout from Lake Huron, at levels similar to perfluorooctanoic acid.

  1. Naturally occurring radioactive material (NORM) from a former phosphoric acid processing plant.

    PubMed

    Beddow, H; Black, S; Read, D

    2006-01-01

    In recent years there has been an increasing awareness of the radiological impact of non-nuclear industries that extract and/or process ores and minerals containing naturally occurring radioactive material (NORM). These industrial activities may result in significant radioactive contamination of (by-) products, wastes and plant installations. In this study, scale samples were collected from a decommissioned phosphoric acid processing plant. To determine the nature and concentration of NORM retained in pipe-work and associated process plant, four main areas of the site were investigated: (1) the 'Green Acid Plant', where crude acid was concentrated; (2) the green acid storage tanks; (3) the Purified White Acid (PWA) plant, where inorganic impurities were removed; and (4) the solid waste, disposed of on-site as landfill. The scale samples predominantly comprise the following: fluorides (e.g. ralstonite); calcium sulphate (e.g. gypsum); and an assemblage of mixed fluorides and phosphates (e.g. iron fluoride hydrate, calcium phosphate), respectively. The radioactive inventory is dominated by 238U and its decay chain products, and significant fractionation along the series occurs. Compared to the feedstock ore, elevated concentrations (< or =8.8 Bq/g) of 238U were found to be retained in installations where the process stream was rich in fluorides and phosphates. In addition, enriched levels (< or =11 Bq/g) of 226Ra were found in association with precipitates of calcium sulphate. Water extraction tests indicate that many of the scales and waste contain significantly soluble materials and readily release radioactivity into solution.

  2. Naturally occurring radioactive material (NORM) from a former phosphoric acid processing plant.

    PubMed

    Beddow, H; Black, S; Read, D

    2006-01-01

    In recent years there has been an increasing awareness of the radiological impact of non-nuclear industries that extract and/or process ores and minerals containing naturally occurring radioactive material (NORM). These industrial activities may result in significant radioactive contamination of (by-) products, wastes and plant installations. In this study, scale samples were collected from a decommissioned phosphoric acid processing plant. To determine the nature and concentration of NORM retained in pipe-work and associated process plant, four main areas of the site were investigated: (1) the 'Green Acid Plant', where crude acid was concentrated; (2) the green acid storage tanks; (3) the Purified White Acid (PWA) plant, where inorganic impurities were removed; and (4) the solid waste, disposed of on-site as landfill. The scale samples predominantly comprise the following: fluorides (e.g. ralstonite); calcium sulphate (e.g. gypsum); and an assemblage of mixed fluorides and phosphates (e.g. iron fluoride hydrate, calcium phosphate), respectively. The radioactive inventory is dominated by 238U and its decay chain products, and significant fractionation along the series occurs. Compared to the feedstock ore, elevated concentrations (< or =8.8 Bq/g) of 238U were found to be retained in installations where the process stream was rich in fluorides and phosphates. In addition, enriched levels (< or =11 Bq/g) of 226Ra were found in association with precipitates of calcium sulphate. Water extraction tests indicate that many of the scales and waste contain significantly soluble materials and readily release radioactivity into solution. PMID:16303218

  3. Development of ternary alloy cathode catalysts for phosphoric acid fuel cells: Final report

    SciTech Connect

    Jalan, V.; Kosek, J.; Giner, J.; Taylor, E. J.; Anderson, E.; Bianchi, V.; Brooks, C.; Cahill, K.; Cropley, C.; Desai, M.; Frost, D.; Morriseau, B.; Paul, B.; Poirier, J.; Rousseau, M.; Swette, L.; Waterhouse, R.

    1988-11-01

    The overall objective of the program was the identification development and incorporation of high activity platinum ternary alloys on corrosion resistant supports, for use in advanced phosphoric acid fuel cells. Two high activity ternary alloys, Pr-Cr-Ce and Pt-Ni-Co, both supported on Vulcan XC-72, were identified during the course of the program. The Pr-Ni-Co system was selected for optimization, including preparation and evaluation on corrosion resistant supports such as 2700/degree/C heat-treated Vulcan XC-72 and 2700/degree/ heat-treated Black Pearls 2000. A series of tests identified optimum metal ratios, heat-treatment temperatures and heat-treatment atmospheres for the Pr-Ni-Co system. During characterization testing, it was discovered that approximately 50% of the nickel and cobalt present in the starting material could be removed, subsequent to alloy formation, without degrading performance. Extremely stable full cell performance was observed for the Pt-Ni-Co system during a 10,000 hour atmosphere pressure life test. Several theories are proposed to explain the enhancement in activity due to alloy formation. Recommendations are made for future research in this area. 62 refs., 23 figs., 27 tabs.

  4. Lignin hydrolysis and phosphorylation mechanism during phosphoric acid-acetone pretreatment: a DFT study.

    PubMed

    Qin, Wu; Wu, Lingnan; Zheng, Zongming; Dong, Changqing; Yang, Yongping

    2014-12-18

    The study focused on the structural sensitivity of lignin during the phosphoric acid-acetone pretreatment process and the resulting hydrolysis and phosphorylation reaction mechanisms using density functional theory calculations. The chemical stabilities of the seven most common linkages (β-O-4, β-β, 4-O-5, β-1, 5-5, α-O-4, and β-5) of lignin in H3PO4, CH3COCH3, and H2O solutions were detected, which shows that α-O-4 linkage and β-O-4 linkage tend to break during the phosphoric acid-acetone pretreatment process. Then α-O-4 phosphorylation and β-O-4 phosphorylation follow a two-step reaction mechanism in the acid treatment step, respectively. However, since phosphorylation of α-O-4 is more energetically accessible than phosphorylation of β-O-4 in phosphoric acid, the phosphorylation of α-O-4 could be controllably realized under certain operational conditions, which could tune the electron and hole transfer on the right side of β-O-4 in the H2PO4- functionalized lignin. The results provide a fundamental understanding for process-controlled modification of lignin and the potential novel applications in lignin-based imprinted polymers, sensors, and molecular devices.

  5. Analytical applications of condensed phosphoric acid-I Determination of ferrous and total iron in iron ores after decomposition with condensed phosphoric acid.

    PubMed

    Mizoguchi, T; Ishii, H

    1978-06-01

    A simple method is described for the determination of ferrous and total iron in iron ores. Iron ores are dissolved by condensed phosphoric acid (CPA) very rapidly without any tedious and time-consuming manipulations such as elimination of silica and filtration. Under the proposed conditions (amount of sample 100 mg, amount of CPA added 10 g, heating temperature 290 degrees , heating time 30 min), magnetite, limonite and hematite are completely dissolved. The iron content can be determined in the presence of condensed phosphoric acid by titration with dichromate solution, if a slight modification is made. The total iron in iron ores, determined by the present method, is in agreement with that found by the JIS method. The ferrous iron in iron ores can be determined by dissolving the samples with CPA in a nitrogen atmosphere and titrating with dichromate solution. Chelatometric titration of iron after solvent extraction with MIBK from solutions prepared by use of CPA is found to be accurate for samples such as pyrite cinder. The ability of CPA to dissolve various materials has been investigated.

  6. Preparation and evaluation of advanced catalysts for phosphoric acid fuel cells

    NASA Technical Reports Server (NTRS)

    Stonehart, P.; Baris, J.; Hockmuth, J.; Pagliaro, P.

    1984-01-01

    The platinum electrocatalysts were characterized for their crystallite sizes and the degree of dispersion on the carbon supports. One application of these electrocatalysts was for anodic oxidation of hydrogen in hot phosphoric acid fuel cells, coupled with the influence of low concentrations of carbon monoxide in the fuel gas stream. In a similar way, these platinum on carbon electrocatalysts were evaluated for oxygen reduction in hot phosphoric acid. Binary noble metal alloys were prepared for anodic oxidation of hydrogen and noble metal-refractory metal mixtures were prepared for oxygen reduction. An exemplar alloy of platinum and palladium (50/50 atom %) was discovered for anodic oxidation of hydrogen in the presence of carbon monoxide, and patent disclosures were submitted. For the cathode, platinum-vanadium alloys were prepared showing improved performance over pure platinum. Preliminary experiments on electrocatalyst utilization in electrode structures showed low utilization of the noble metal when the electrocatalyst loading exceeded one weight percent on the carbon.

  7. Recovery of Uranium from Wet Phosphoric Acid by Solvent Extraction Processes

    SciTech Connect

    Beltrami, Denis; Cote, Gérard; Mokhtari, Hamid; Courtaud, Bruno; Moyer, Bruce A.; Chagnes, Alexandre

    2014-11-17

    Between 1951 and 1991, we developed about 17 processes to recover uranium from wet phosphoric acid (WPA), but the viability of these processes was subject to the variation of the uranium price market. Nowadays, uranium from WPA appears to be attractive due to the increase of the global uranium demand resulting from the emergence of developing countries. Moreover, the increasing demand provides impetus for a new look at the applicable technology with a view to improvements as well as altogether new approaches. This paper gives an overview on extraction processes developed in the past to recover uranium from wet phosphoric acid (WPA) as well as the physicochemistry involved in these processes. Recent advances concerning the development of new extraction systems are also reported and discussed.

  8. Potential of phosphoric acid-catalyzed pretreatment and subsequent enzymatic hydrolysis for biosugar production from Gracilaria verrucosa.

    PubMed

    Kwon, Oh-Min; Kim, Sung-Koo; Jeong, Gwi-Taek

    2016-07-01

    This study combined phosphoric acid-catalyzed pretreatment and enzymatic hydrolysis to produce biosugars from Gracilaria verrucosa as a potential renewable resource for bioenergy applications. We optimized phosphoric acid-catalyzed pretreatment conditions to 1:10 solid-to-liquid ratio, 1.5 % phosphoric acid, 140 °C, and 60 min reaction time, producing a 32.52 ± 0.06 % total reducing sugar (TRS) yield. By subsequent enzymatic hydrolysis, a 68.61 ± 0.90 % TRS yield was achieved. These results demonstrate the potential of phosphoric acid to produce biosugars for biofuel and biochemical production applications. PMID:27003825

  9. Potential of phosphoric acid-catalyzed pretreatment and subsequent enzymatic hydrolysis for biosugar production from Gracilaria verrucosa.

    PubMed

    Kwon, Oh-Min; Kim, Sung-Koo; Jeong, Gwi-Taek

    2016-07-01

    This study combined phosphoric acid-catalyzed pretreatment and enzymatic hydrolysis to produce biosugars from Gracilaria verrucosa as a potential renewable resource for bioenergy applications. We optimized phosphoric acid-catalyzed pretreatment conditions to 1:10 solid-to-liquid ratio, 1.5 % phosphoric acid, 140 °C, and 60 min reaction time, producing a 32.52 ± 0.06 % total reducing sugar (TRS) yield. By subsequent enzymatic hydrolysis, a 68.61 ± 0.90 % TRS yield was achieved. These results demonstrate the potential of phosphoric acid to produce biosugars for biofuel and biochemical production applications.

  10. Manual of phosphoric acid fuel cell stack three-dimensional model and computer program

    NASA Technical Reports Server (NTRS)

    Lu, C. Y.; Alkasab, K. A.

    1984-01-01

    A detailed distributed mathematical model of phosphoric acid fuel cell stack have been developed, with the FORTRAN computer program, for analyzing the temperature distribution in the stack and the associated current density distribution on the cell plates. Energy, mass, and electrochemical analyses in the stack were combined to develop the model. Several reasonable assumptions were made to solve this mathematical model by means of the finite differences numerical method.

  11. Origins of Selectivity and General Model for Chiral Phosphoric Acid-Catalyzed Oxetane Desymmetrizations.

    PubMed

    Champagne, Pier Alexandre; Houk, K N

    2016-09-28

    The origins of the high enantioselectivity of chiral phosphoric acid-catalyzed oxetane desymmetrizations were investigated by density functional theory (DFT) calculations. Distortion of the catalyst structure, caused by steric crowding in the catalyst pocket of one enantiomeric transition state, is the main cause for stereochemical preference. A general model was developed to assist in the rational design of new catalysts for related transformations. PMID:27629045

  12. Nitric-phosphoric acid oxidation of solid and liquid organic materials

    SciTech Connect

    Pierce, R.A.; Smith, J.R.; Poprik, D.C.

    1995-02-01

    Nitric-phosphoric acid oxidation has been developed specifically to address issues that face the Savannah River Site, other defense-related facilities, private industry, and small-volume generators such as university and medical laboratories. Initially tested to destroy and decontaminate SRS solid, Pu-contaminated job-control waste, the technology has also exhibited potential for remediating hazardous and mixed-hazardous waste forms. The process is unique to Savannah River and offers a valuable alternative to other oxidation processes that require extreme temperatures and/or elevated pressures. To address the broad categories of waste, many different organic compounds which represent a cross-section of the waste that must be treated have been successfully oxidized. Materials that have been quantitatively oxidized at atmospheric pressure below 180{degrees}C include neoprene, cellulose, EDTA, tributylphosphate, and nitromethane. More stable compounds such as benzoic acid, polyethylene, oils, and resins have been completely decomposed below 200{degrees}C and 10 psig. The process uses dilute nitric acid in a concentrated phosphoric acid media as the main oxidant for the organic compounds. Phosphoric acid allow nitric acid to be retained in solution well above its normal boiling point. The reaction forms NOx vapors which can be reoxidized and recycled using air and water. The addition of 0.001M Pd(II) reduces CO generation to near 1% of the released carbon gases. The advantages of this process are that it is straightforward, uses relatively inexpensive reagents, operates at relatively low temperature and pressure, and produces final solutions which are compatible with stainless steel equipment. For organic wastes, all carbon, hydrogen, and nitrogen are converted to gaseous products. If interfaced with an acid recovery system which converts NOx back to nitric acid, the net oxidizer would be oxygen from air.

  13. Estimates of the occupational exposure to tenorm in the phosphoric acid production plant in Iran.

    PubMed

    Fathabadi, N; Vasheghani Farahani, M; Moradi, M; Hadadi, B

    2012-09-01

    Phosphate rock is used world wide for manufacturing phosphoric acid and several chemical fertilisers. It is known that the phosphate rock contains various concentrations of uranium, thorium, radium and their daughters. The subject of this study is the evaluation of the radiation exposure to workers in the phosphoric acid production plant due to technologically enhanced naturally occurring radioactive materials that can result from the presence of naturally occurring radioactive materials in phosphate ores used in the manufacturing of phosphoric acid. Radiation exposure due to direct gamma radiation, dust inhalation and radon gas has been investigated and external and internal doses of exposed workers have been calculated. Natural radioactivity due to (40)K, (226)Ra and (232)Th have been measured in phosphate rock, phosphogypsum, chemical fertilisers and other samples by gamma spectrometry system with a high-purity germanium. The average concentrations of (226)Ra and (40)K observed in the phosphate rock are 760 and 80 Bq kg(-1), respectively. Annual effective dose from external radiation had a mean value of ∼0.673 mSv y(-1). Dust sampling revealed greatest values in the storage area. The annual average effective dose from inhalation of long-lived airborne was 0.113 mSv y(-1). Radon gas concentrations in the processing plant and storage area were found to be of the same value as the background. In this study the estimated annual effective doses to workers were below 1 mSv y(-1). PMID:22361352

  14. Technology development for phosphoric acid fuel cell powerplant, phase 2

    NASA Technical Reports Server (NTRS)

    Christner, L.

    1979-01-01

    A technique for producing an acid inventory control member by spraying FEP onto a partially screened carbon paper backing is discussed. Theoretical analysis of the acid management indicates that the vapor composition of 103% H3PO4 is approximately 1.0 ppm P4O10. An SEM evaluation of corrosion resistance of phenolic resins and graphite/phenolic resin composites in H3PO4 at 185 C shows specific surface etching. Carbonization of graphite/phenolic bipolar plates is achieved without blistering.

  15. Purification of industrial phosphoric acid (54 %) using Fe-pillared bentonite.

    PubMed

    Hamza, Wiem; Chtara, Chaker; Benzina, Mourad

    2016-08-01

    The current problem of excess impurities in industrial phosphoric acid (IPA) 54 % P2O5 makes phosphates industries look toward low-cost but efficient adsorbents. In the present study, iron-oxide-modified bentonite (Fe-PILB) was prepared and investigated as a possible adsorbent for the removal of organic matter (OM) like humic acid (HA), chromium (Cr(III)), and zinc (Zn(II)) from IPA aqueous solutions. These adsorbents were characterized using XRD, TEM, and BET. The adsorption of impurities is well described by the pseudo-second-order model. The results indicate that Fe-PILB has a good ability to resist co-existing anions and the low-pH condition of IPA and owns a relatively high-removal capacity of 80.42 and 25 % for OM, Cr(III), and Zn(II). The mechanism of adsorption may be described by the ligand and ion exchange that happened on the active sites. The selected order of adsorption OM > Cr(3+) > Zn(2+) showed the importance of the competitive phenomenon onto bentonite materials' pore adsorption. For the adsorption of OM at the low pH of IPA, H-bond complexation was the dominant mechanism. From the adsorption of heavy metals and OM complex compounds contained in IPA 54 % on Fe-PILB, the bridging of humic acid between bentonite and heavy metals (Zn(II) or Cr(III)) is proposed as the dominant adsorption mechanism (bentonite-HA-Me). Overall, the results obtained in this study indicate Fe-pillared bentonite possesses a potential for the practical application of impurity (OM, Zn(II), and Cr(III)) removal from IPA aqueous solutions. PMID:26514573

  16. Traveling Wave Ion Mobility Mass Spectrometry and Ab Initio Calculations of Phosphoric Acid Clusters

    NASA Astrophysics Data System (ADS)

    Lavanant, Hélène; Tognetti, Vincent; Afonso, Carlos

    2014-04-01

    Positive and negative ion electrospray mass spectra obtained from 50 mM phosphoric acid solutions presented a large number of phosphoric acid clusters: [(H3PO4)n + zH] z+ or [(H3PO4)n - zH] z- , with n up to 200 and z up to 4 for positively charged clusters, and n up to 270 and z up to 7 for negatively charged cluster ions. Ion mobility experiments allowed very explicit separation of the different charge states. Because of the increased pressures involved in ion mobility experiments, dissociation to smaller clusters was observed both in the trap and transfer areas. Voltages along the ion path could be optimized so as to minimize this effect, which can be directly associated with the cleavage of hydrogen bonds. Having excluded the ion mobility times that resulted from dissociated ions, each cluster ion appeared at a single drift time. These drift times showed a linear progression with the number of phosphoric atoms for cluster ions of the same charge state. Cross section calculations were carried out with MOBCAL on DFT optimized geometries with different hydrogen locations and with three types of atomic charges. DFT geometry optimizations yielded roughly spherical structures. Our results for nitrogen gas interaction cross sections showed that values were dependent on the atomic charges definition used in the MOBCAL calculation. This pinpointed the necessity to define a clear theoretical framework before any comparative interpretations can be attempted with uncharacterized compounds.

  17. Traveling wave ion mobility mass spectrometry and ab initio calculations of phosphoric acid clusters.

    PubMed

    Lavanant, Hélène; Tognetti, Vincent; Afonso, Carlos

    2014-04-01

    Positive and negative ion electrospray mass spectra obtained from 50 mM phosphoric acid solutions presented a large number of phosphoric acid clusters: [(H3PO4)n + zH](z+) or [(H3PO4)n - zH](z-), with n up to 200 and z up to 4 for positively charged clusters, and n up to 270 and z up to 7 for negatively charged cluster ions. Ion mobility experiments allowed very explicit separation of the different charge states. Because of the increased pressures involved in ion mobility experiments, dissociation to smaller clusters was observed both in the trap and transfer areas. Voltages along the ion path could be optimized so as to minimize this effect, which can be directly associated with the cleavage of hydrogen bonds. Having excluded the ion mobility times that resulted from dissociated ions, each cluster ion appeared at a single drift time. These drift times showed a linear progression with the number of phosphoric atoms for cluster ions of the same charge state. Cross section calculations were carried out with MOBCAL on DFT optimized geometries with different hydrogen locations and with three types of atomic charges. DFT geometry optimizations yielded roughly spherical structures. Our results for nitrogen gas interaction cross sections showed that values were dependent on the atomic charges definition used in the MOBCAL calculation. This pinpointed the necessity to define a clear theoretical framework before any comparative interpretations can be attempted with uncharacterized compounds.

  18. Removal of heavy metals and lanthanides from industrial phosphoric acid process liquors

    SciTech Connect

    Koopman, C.; Witkamp, G.J.; Van Rosmalen, G.M.

    1999-11-01

    To diminish the discharge of heavy metals and lanthanides by the phosphoric acid industry, these impurities have to be removed from the mother liquor before their incorporation in the gypsum crystals. This can best be achieved by means of solvent extraction or ion exchange during the recrystallization of hemihydrate to dihydrate gypsum. Various commercial carriers and two ion-exchange resins were screened for their efficiency and selectivity. Light and heavy lanthanide ions are extracted from the recrystallization acid by didodecylnaphthalenesulfonic acid (Nacure 1052) and di(2-ethylhexyl)phosphoric acid (D2EHPA), and the heavy-metal ions by bis(2,4,4-trimethylpentyl)dithiophosphinic acid (Cyanex 301) and by bis(2,4,4-trimethylpentyl)monothiophosphinic acid (Cyanex 302). Mercury is also extracted by the anion carriers tri(C{sub 8}-C{sub 10})amine (Alamine 336) and tri(C{sub 8}-C{sub 10}) monomethyl ammonium chloride (Aliquat 336). Both Dowex C-500 and Amberlite IR-120 extract lanthanide and heavy-metal ions. Unfortunately, D2EHPA, Nacure 1052, and the two ion-exchange resins also show affinity for ions present in much higher concentrations, like calcium or iron ions.

  19. Laser-activated remote phosphor light engine for projection applications

    NASA Astrophysics Data System (ADS)

    Daniels, Martin; Mehl, Oliver; Hartwig, Ulrich

    2015-09-01

    Recent developments in blue emitting laser diodes enable attractive solutions in projection applications using phosphors for efficient light conversion with very high luminance levels. Various commercially available projectors incorporating this technology have entered the market in the past years. While luminous flux levels are still comparable to lamp-based systems, lifetime expectations of classical lamp systems are exceeded by far. OSRAM GmbH has been exploring this technology for several years and has introduced the PHASER® brand name (Phosphor + laser). State-of-the-art is a rotating phosphor wheel excited by blue laser diodes to deliver the necessary primary colors, either sequentially for single-imager projection engines, or simultaneously for 3-panel systems. The PHASER® technology enables flux and luminance scaling, which allows for smaller imagers and therefore cost-efficient projection solutions. The resulting overall efficiency and ANSI lumen specification at the projection screen of these systems is significantly determined by the target color gamut and the light transmission efficiency of the projection system. With increasing power and flux level demand, thermal issues, especially phosphor conversion related, dominate the opto-mechanical system design requirements. These flux levels are a great challenge for all components of an SSL-projection system (SSL:solid-state lighting). OSRAḾs PHASER® light engine platform is constantly expanded towards higher luminous flux levels as well as higher luminance levels for various applications. Recent experiments employ blue laser pump powers of multiple 100 Watts to excite various phosphors resulting in luminous flux levels of more than 40 klm.

  20. Design of a Brønsted acid with two different acidic sites: synthesis and application of aryl phosphinic acid-phosphoric acid as a Brønsted acid catalyst.

    PubMed

    Momiyama, N; Narumi, T; Terada, M

    2015-12-11

    A Brønsted acid with two different acidic sites, aryl phosphinic acid-phosphoric acid, has been synthesized. Its catalytic performance was assessed in the hetero-Diels-Alder reaction of aldehyde hydrates with Danishefsky's diene, achieving high reaction efficiency. PMID:26445921

  1. Production of technical grade phosphoric acid from incinerator sewage sludge ash (ISSA).

    PubMed

    Donatello, S; Tong, D; Cheeseman, C R

    2010-01-01

    The recovery of phosphorus from sewage sludge ash samples obtained from 7 operating sludge incinerators in the UK using a sulfuric acid washing procedure to produce a technical grade phosphoric acid product has been investigated. The influences of reaction time, sulfuric acid concentration, liquid to solid ratio and source of ISSA on P recovery have been examined. The optimised conditions were the minimum stoichiometric acid requirement, a reaction time of 120 min and a liquid to solid ratio of 20. Under these conditions, average recoveries of between 72% and 91% of total phosphorus were obtained. Product filtrate was purified by passing through a cation exchange column, concentrated to 80% H(3)PO(4) and compared with technical grade H(3)PO(4) specifications. The economics of phosphate recovery by this method are briefly discussed.

  2. Effect of fungal and phosphoric acid pretreatment on ethanol production from oil palm empty fruit bunches (OPEFB).

    PubMed

    Ishola, Mofoluwake M; Isroi; Taherzadeh, Mohammad J

    2014-08-01

    Oil palm empty fruit bunches (OPEFB), a lignocellulosic residue of palm oil industries was examined for ethanol production. Milled OPEFB exposed to simultaneous saccharification and fermentation (SSF) with enzymes and Saccharomyces cerevisiae resulted just in 14.5% ethanol yield compared to the theoretical yield. Therefore, chemical pretreatment with phosphoric acid, a biological pretreatment with white-rot fungus Pleurotus floridanus, and their combination were carried out on OPEFB prior to the SSF. Pretreatment with phosphoric acid, combination of both methods and just fungal pretreatment improved the digestibility of OPEFB by 24.0, 16.5 and 4.5 times, respectively. During the SSF, phosphoric acid pretreatment, combination of fungal and phosphoric acid pretreatment and just fungal pretreatment resulted in the highest 89.4%, 62.8% and 27.9% of the theoretical ethanol yield, respectively. However, the recovery of the OPEFB after the fungal pretreatment was 98.7%, which was higher than after phosphoric acid pretreatment (36.5%) and combined pretreatment (45.2%).

  3. Manual of phosphoric acid fuel cell power plant optimization model and computer program

    NASA Technical Reports Server (NTRS)

    Lu, C. Y.; Alkasab, K. A.

    1984-01-01

    An optimized cost and performance model for a phosphoric acid fuel cell power plant system was derived and developed into a modular FORTRAN computer code. Cost, energy, mass, and electrochemical analyses were combined to develop a mathematical model for optimizing the steam to methane ratio in the reformer, hydrogen utilization in the PAFC plates per stack. The nonlinear programming code, COMPUTE, was used to solve this model, in which the method of mixed penalty function combined with Hooke and Jeeves pattern search was chosen to evaluate this specific optimization problem.

  4. Quantum-chemical studies of dimethylformamide 1 : 1 complexes with phosphoric acid

    NASA Astrophysics Data System (ADS)

    Krest'yaninov, M. A.; Kiselev, M. G.; Safonova, L. P.

    2012-12-01

    The structures of two phosphoric acid conformations, dimethylformamide (DMFA), four protonated DMFA forms, and nine DMFA-H3PO4 complexes in which the proton acceptor is a oxygen or nitrogen atom of the DMFA molecule are optimized by DFT/B3LYP using the 6-31++G( d, p) basis set. The structural changes in DMFA that occur upon its protonation are discussed. The stabilization energy and transferred charge values upon the formation of a hydrogen bond are calculated for all of the studied complexes by means of NBO analysis. The potential energy surface is scanned to study the possibility of proton transfer.

  5. SOLVENT EXTRACTION PROCESS FOR THE RECOVERY OF METALS FROM PHOSPHORIC ACID

    DOEpatents

    Bailes, R.H.; Long, R.S.

    1958-11-01

    > A solvent extraction process is presented for recovering metal values including uranium, thorium, and other lanthanide and actinide elements from crude industrial phosphoric acid solutions. The process conslsts of contacting said solution with an immisclble organic solvent extractant containing a diluent and a material selected from the group consisting of mono and di alkyl phosphates, alkyl phosphonates and alkyl phosphites. The uranlum enters the extractant phase and is subsequently recovered by any of the methods known to the art. Recovery is improved if the phosphate solution is treated with a reducing agent such as iron or aluminum powder prior to the extraction step.

  6. Computer-based phosphoric acid fuel cell analytical tools Descriptions and usages

    NASA Technical Reports Server (NTRS)

    Lu, C.; Presler, A. F.

    1987-01-01

    Simulation models have been developed for the prediction of phosphoric acid fuel cell (PAFC) powerplant system performance under both transient and steady operation conditions, as well as for the design of component configurations and for optimal systems synthesis. These models, which are presently computer-implemented, are an engineering and a system model; the former being solved by the finite difference method to determine the balances and properties of different sections, and the latter using thermodynamic balances to set up algebraic equations that yield physical and chemical properties of the stream for one operating condition.

  7. Status of commercial phosphoric acid fuel cell power plant system development

    NASA Technical Reports Server (NTRS)

    Warshay, M.

    1987-01-01

    A technology development and commercial feasibility evaluation is presented for phosphoric acid fuel cells (PAFCs) applicable to electric utility operations. The correction of identified design deficiencies in the control card and water treatment subsystems is projected to be able to substantially increase average powerplant availability from the 63 percent achieved in recent field tests of a PAFC system. Current development work is proceeding under NASA research contracts at the output levels of a multimegawatt facility for electric utility use, a multikilowatt on-site integrated energy generation facility, and advanced electrocatalysts applicable to PAFCs.

  8. Reductive stripping process for the recovery of uranium from wet-process phosphoric acid

    DOEpatents

    Hurst, Fred J.; Crouse, David J.

    1984-01-01

    A reductive stripping flow sheet for recovery of uranium from wet-process phosphoric acid is described. Uranium is stripped from a uranium-loaded organic phase by a redox reaction converting the uranyl to uranous ion. The uranous ion is reoxidized to the uranyl oxidation state to form an aqueous feed solution highly concentrated in uranium. Processing of this feed through a second solvent extraction cycle requires far less stripping reagent as compared to a flow sheet which does not include the reductive stripping reaction.

  9. Origin of Kinetic Resolution of Hydroxy Esters through Catalytic Enantioselective Lactonization by Chiral Phosphoric Acids.

    PubMed

    Changotra, Avtar; Sunoj, Raghavan B

    2016-08-01

    Kinetic resolution is a widely used strategy for separation and enrichment of enantiomers. Using density functional theory computations, the origin of how a chiral BINOL-phosphoric acid catalyzes the selective lactonization of one of the enantiomers of α-methyl γ-hydroxy ester is identified. In a stepwise mechanism, the stereocontrolling transition state for the addition of the hydroxyl group to the si face of the ester carbonyl in the case of the S isomer exhibits a network of more effective noncovalent interactions between the substrate and the chiral catalyst. PMID:27463593

  10. Extraction equilibrium of indium(III) from nitric acid solutions by di(2-ethylhexyl)phosphoric acid dissolved in kerosene.

    PubMed

    Tsai, Hung-Sheng; Tsai, Teh-Hua

    2012-01-04

    The extraction equilibrium of indium(III) from a nitric acid solution using di(2-ethylhexyl) phosphoric acid (D2EHPA) as an acidic extractant of organophosphorus compounds dissolved in kerosene was studied. By graphical and numerical analysis, the compositions of indium-D2EHPA complexes in organic phase and stoichiometry of the extraction reaction were examined. Nitric acid solutions with various indium concentrations at 25 °C were used to obtain the equilibrium constant of InR₃ in the organic phase. The experimental results showed that the extraction distribution ratios of indium(III) between the organic phase and the aqueous solution increased when either the pH value of the aqueous solution and/or the concentration of the organic phase extractant increased. Finally, the recovery efficiency of indium(III) in nitric acid was measured.

  11. The Partitioning of Acetic, Formic, and Phosphoric Acids Between Liquid Water and Steam

    SciTech Connect

    Gruszkiewicz, M.S.; Marshall, S.L.; Palmer, D.A.; Simonson, J.M.

    1999-06-22

    The chemical carryover of impurities and treatment chemicals from the boiler to the steam phase, and ultimately to the low-pressure turbine and condenser, can be quantified based on laboratory experiments preformed over ranges of temperature, pH, and composition. The two major assumptions are that thermodynamic equilibrium is maintained and no deposition, adsorption or decomposition occurs. The most recent results on acetic, formic and phosphoric acids are presented with consideration of the effects of hydrolysis and dimerization reactions. Complications arising from thermal decomposition of the organic acids are discussed. The partitioning constants for these acids and other solutes measured in this program have been incorporated into a simple thermodynamic computer code that calculates the effect of chemical and mechanical carryover on the composition of the condensate formed to varying extents in the water/steam cycle.

  12. Recovery of organic extractant from secondary emulsions formed in the extraction of uranium from wet-process phosphoric acid

    SciTech Connect

    Korchnak, J.D.; Fett, R.H.G.

    1984-01-03

    Uranium in wet-process phosphoric acid is extracted with an organic extractant. The pregnant extractant is then centrifuged to separate contaminants from the extractant. Secondary emulsions obtained by separating the contaminants following centrifugation are mixed with water or an acid leaching solution. After mixing, the mixture is centrifuged to separate and recover extractant which is recycled for stripping.

  13. Fiber optic illumination by laser activated remote phosphor

    NASA Astrophysics Data System (ADS)

    Hartwig, Ulrich

    2012-10-01

    For some fiber optic applications, like high-end endoscopy, light sources with high luminance are necessary. Currently, short arc discharge lamps are being used. However, more and more LED solutions are trying to compete, but they can not yet reach the performance obtainable by 300 W Xenon short arc discharge lamps. To make this field of application accessible for solid state light sources, a new approach is necessary. Diode lasers have rapidly advanced in the past years. This is particularly true for multimode laser diodes emitting at around 445 nm wavelength. Single diodes emitting more than 1 W of optical power are already available. These laser sources exhibit extremely high radiance, thus they can be focused onto very small areas. Phosphors placed near the focus can result in high luminance sources. On the basis of this idea, a device has been developed to match the performance of a state of the art 300 W Xenon lamp system. An array of laser diodes is used to illuminate a phosphor plate which converts the blue pump light into yellow light. The converted light is collected and adapted to the application by a tapered TIR rod. To achieve a color point on the Planckian locus at 6000 K, the light of an LED emitting at around 460 nm is superimposed to the converted light.

  14. Optimizing the saccharification of sugar cane bagasse using dilute phosphoric acid followed by fungal cellulases.

    PubMed

    Geddes, C C; Peterson, J J; Roslander, C; Zacchi, G; Mullinnix, M T; Shanmugam, K T; Ingram, L O

    2010-03-01

    A low level of phosphoric acid (1% w/w on dry bagasse basis, 160 degrees C and above, 10 min) was shown to effectively hydrolyze the hemicellulose in sugar cane bagasse into monomers with minimal side reactions and to serve as an effective pre-treatment for the enzymatic hydrolysis of cellulose. Up to 45% of the remaining water-insoluble solids (WIS) was digested to sugar monomers by a low concentration of Biocellulase W (0.5 filter paper unit/gWIS) supplemented with beta-glucosidase, although much higher levels of cellulase (100-fold) were required for complete hydrolysis. After neutralization and nutrient addition, phosphoric acid syrups of hemicellulose sugars were fermented by ethanologenic Escherichia coli LY160 without further purification. Fermentation of these syrups was preceded by a lag that increased with increased pre-treatment temperature. Further improvements in organisms and optimization of steam treatments may allow the co-fermentation of sugars derived from hemicellulose and cellulose, eliminating need for liquid-solid separation, sugar purification, and separate fermentations.

  15. Characterization of phosphogypsum wastes associated with phosphoric acid and fertilizers production.

    PubMed

    El Afifi, E M; Hilal, M A; Attallah, M F; El-Reefy, S A

    2009-05-01

    The present work is directed to characterize the phosphogypsum (PG) wastes associated with phosphoric acid produced by the wet process in industrial facility for the production of fertilizers and chemicals in Egypt. The PG waste samples were characterized in terms of spectroscopic analysis (X-ray diffraction, X-ray fluorescence, IR spectra) and radiometric analysis (gamma- and alpha-measurements). The gamma-ray measurements showed that the average activity concentrations are 140+/-12.6, 459+/-36.7, 323+/-28.4, 8.3+/-0.76 and 64.3+/-4.1 Bq/kg for U-238, Ra-226, Pb-210, Th-232 and K-40, respectively. The alpha-particle measurements of uranium isotopes showed that the average activity concentrations of U-238, U-235 and U-234 were 153+/-9.8, 7+/-0.38, 152+/-10.4 Bq/kg, respectively. The average radiochemical recovery (%) of the destructive alpha-particle measurements is approximately 70% with a resolution (FWHM) of approximately 30 keV. Activity ratios of U-238/Ra-226 and U-238/Pb-210 were less than unity (i.e., <1) and equal to 0.31+/-0.02 and 0.47+/-0.16, respectively. The isotopic ratios of U-238/U-235 and U-238/U-234 (in PG and PR samples) were close to the normal values of approximately 21.7 and approximately 1, respectively and are not affected by the wet processing of phosphate rock (PR). The obtained results of PG waste samples were compared with phosphate rock (PR) samples. The radiation hazard indices are namely, radium activity index (Ra-Eq>370 Bq/kg), total absorbed gamma dose rate (D(gamma r)>5 nGy/h) and radon emanation fraction (Rn-EF>20%). Uncertainty of the sample counting was 95% confidence level of sigma. The results indicated the necessity to find suitable routes to decrease and/or redistribute the radionuclide of environmental interest (i.e., Ra-226) in PG wastes, consequently to reduce its radiation impacts in the surrounding environment.

  16. Characterization of phosphogypsum wastes associated with phosphoric acid and fertilizers production.

    PubMed

    El Afifi, E M; Hilal, M A; Attallah, M F; El-Reefy, S A

    2009-05-01

    The present work is directed to characterize the phosphogypsum (PG) wastes associated with phosphoric acid produced by the wet process in industrial facility for the production of fertilizers and chemicals in Egypt. The PG waste samples were characterized in terms of spectroscopic analysis (X-ray diffraction, X-ray fluorescence, IR spectra) and radiometric analysis (gamma- and alpha-measurements). The gamma-ray measurements showed that the average activity concentrations are 140+/-12.6, 459+/-36.7, 323+/-28.4, 8.3+/-0.76 and 64.3+/-4.1 Bq/kg for U-238, Ra-226, Pb-210, Th-232 and K-40, respectively. The alpha-particle measurements of uranium isotopes showed that the average activity concentrations of U-238, U-235 and U-234 were 153+/-9.8, 7+/-0.38, 152+/-10.4 Bq/kg, respectively. The average radiochemical recovery (%) of the destructive alpha-particle measurements is approximately 70% with a resolution (FWHM) of approximately 30 keV. Activity ratios of U-238/Ra-226 and U-238/Pb-210 were less than unity (i.e., <1) and equal to 0.31+/-0.02 and 0.47+/-0.16, respectively. The isotopic ratios of U-238/U-235 and U-238/U-234 (in PG and PR samples) were close to the normal values of approximately 21.7 and approximately 1, respectively and are not affected by the wet processing of phosphate rock (PR). The obtained results of PG waste samples were compared with phosphate rock (PR) samples. The radiation hazard indices are namely, radium activity index (Ra-Eq>370 Bq/kg), total absorbed gamma dose rate (D(gamma r)>5 nGy/h) and radon emanation fraction (Rn-EF>20%). Uncertainty of the sample counting was 95% confidence level of sigma. The results indicated the necessity to find suitable routes to decrease and/or redistribute the radionuclide of environmental interest (i.e., Ra-226) in PG wastes, consequently to reduce its radiation impacts in the surrounding environment. PMID:19272681

  17. Recovery of Uranium from Wet Phosphoric Acid by Solvent Extraction Processes

    DOE PAGES

    Beltrami, Denis; Cote, Gérard; Mokhtari, Hamid; Courtaud, Bruno; Moyer, Bruce A.; Chagnes, Alexandre

    2014-11-17

    Between 1951 and 1991, we developed about 17 processes to recover uranium from wet phosphoric acid (WPA), but the viability of these processes was subject to the variation of the uranium price market. Nowadays, uranium from WPA appears to be attractive due to the increase of the global uranium demand resulting from the emergence of developing countries. Moreover, the increasing demand provides impetus for a new look at the applicable technology with a view to improvements as well as altogether new approaches. This paper gives an overview on extraction processes developed in the past to recover uranium from wet phosphoricmore » acid (WPA) as well as the physicochemistry involved in these processes. Recent advances concerning the development of new extraction systems are also reported and discussed.« less

  18. Recovery of uranium from phosphoric acid medium by polymeric composite beads encapsulating organophosphorus extractants

    SciTech Connect

    Singh, D.K.; Yadav, K.K.; Varshney, L.; Singh, H.

    2013-07-01

    The present study deals with the preparation and evaluation of the poly-ethersulfone (PES) based composite beads encapsulating synergistic mixture of D2EHPA and Cyanex 923 (at 4:1 mole ratio) for the separation of uranium from phosphoric acid medium. SEM was used for the characterization of the composite materials. Addition of 1% PVA (polyvinyl alcohol) improved the internal morphology and porosity of the beads. Additionally, microscopic examination of the composite bead confirmed central coconut type cavity surrounded by porous polymer layer of the beads through which exchange of metal ions take place. Effect of various experimental variables including aqueous acidity, metal ion concentration in aqueous feed, concentration of organic extractant inside the beads, extractant to polymer ratio, liquid to solid (L/S) ratio and temperature on the extraction of uranium was studied. Increase in acidity (1-6 M), L/S ratio (1- 10), metal ion concentration (0.2-3 g/L U{sub 3}O{sub 8}) and polymer to extractant ratio (1:4 -1:10) led to decrease in extraction of uranium. At 5.5 M (comparable to wet process phosphoric acid concentration) the extraction of uranium was about 85% at L/S ratio 5. Increase in extractant concentration inside the bead resulted in enhanced extraction of metal ion. Increase in temperature in the range of 30 to 50 Celsius degrees increased the extraction, whereas further increase to 70 C degrees led to the decrease in extraction of uranium. Amongst various reagents tested, stripping of uranium was quantitative by 12% Na{sub 2}CO{sub 3} solution. Polymeric beads were found to be stable and reusable up-to 10 cycles of extraction/stripping. (authors)

  19. Phosphorous transient enhanced diffusion suppression and activation enhancement with cluster carbon co-implantation

    NASA Astrophysics Data System (ADS)

    Nakashima, Yoshiki; Hamamoto, Nariaki; Nagayama, Tsutomu; Koga, Yuji; Umisedo, Sei; Kawamura, Yasunori; Hashimoto, Masahiro; Onoda, Hiroshi

    2012-11-01

    Carbon co-implantation is well known as an effective method for suppressing boron/phosphorous transient enhanced diffusion (TED). Germanium pre-amorphization implantation (PAI) is usually applied prior to carbon co-implantation for suppressing channeling tail of dopants. In this study, cluster carbon was applied instead of the combination of germanium PAI and monomer carbon co-implantation prior to phosphorous implantation. Dependence of phosphorous activation and TED on amorphous layer thickness, carbon dose, carbon distribution and substrate temperature have been investigated. Cluster carbon implantation enables thick amorphous layer formation and TED suppression at the same time and low temperature implantation enhances the ability of amorphous layer formation so that shallow junction and low Rs can be achieved without Ge implantation.

  20. Phosphorous transient enhanced diffusion suppression and activation enhancement with cluster carbon co-implantation

    SciTech Connect

    Nakashima, Yoshiki; Hamamoto, Nariaki; Nagayama, Tsutomu; Koga, Yuji; Umisedo, Sei; Kawamura, Yasunori; Hashimoto, Masahiro; Onoda, Hiroshi

    2012-11-06

    Carbon co-implantation is well known as an effective method for suppressing boron/phosphorous transient enhanced diffusion (TED). Germanium pre-amorphization implantation (PAI) is usually applied prior to carbon co-implantation for suppressing channeling tail of dopants. In this study, cluster carbon was applied instead of the combination of germanium PAI and monomer carbon co-implantation prior to phosphorous implantation. Dependence of phosphorous activation and TED on amorphous layer thickness, carbon dose, carbon distribution and substrate temperature have been investigated. Cluster carbon implantation enables thick amorphous layer formation and TED suppression at the same time and low temperature implantation enhances the ability of amorphous layer formation so that shallow junction and low Rs can be achieved without Ge implantation.

  1. Luminescence properties of some double-activated zinc-sulphide-type phosphors

    NASA Astrophysics Data System (ADS)

    Popovici, Elisabeth-Jeanne; Aneculaese, Maria; Ursu, Veronica

    1998-07-01

    Silver and copper double activated phosphor samples were synthesized from zinc sulphide prepared by thiosulphate method and with a NaCl-MgCl2 mixture as flux. The thermal treatment was performed in a protective atmosphere at 900 - 1100 degree(s)C. The samples were characterized by crystalline structure (XRD patterns) and luminescent properties (emission spectra, decay curves). An intensification effect of the copper green fluorescence by silver ions was put in evidence. Conditions for a good green emitting phosphor were established.

  2. Thermoluminescence characterization of Dy(3+) -activated Mg₅ (BO₃ )₃ F low Z(eff) phosphor.

    PubMed

    Wani, Javaid A; Dhoble, N S; Dhoble, S J

    2013-01-01

    Thermoluminescence characteristics of Dy(3+) -activated Mg₅ (BO₃ )₃ F low Z(eff) phosphor are described. The Mg₅ (BO₃ )₃ F phosphor doped with Dy(3+) as activator was prepared by the modified solid-state reaction. Formation of the compound was confirmed by use of X-ray powder diffraction. The X-ray powder diffraction pattern of the as-prepared compound shows a good match with the available JCPDS data. The γ-irradiated Mg₅ (BO₃ )₃ F:Dy(3+) phosphor shows a simple glow curve peaking at about 148°C indicating that only one type of trap is being activated within a particular temperature range. The kinetic parameters, including activation energy and frequency factor were determined using Chen's method. The activation energy and frequency factors were 0.75 eV and 4.508 × 10(9) /s respectively. The Z(eff) ofMg₅ (BO₃ )₃ F:Dy(3+) phosphor was 9.84. PMID:23055350

  3. Thermoluminescence characterization of Dy(3+) -activated Mg₅ (BO₃ )₃ F low Z(eff) phosphor.

    PubMed

    Wani, Javaid A; Dhoble, N S; Dhoble, S J

    2013-01-01

    Thermoluminescence characteristics of Dy(3+) -activated Mg₅ (BO₃ )₃ F low Z(eff) phosphor are described. The Mg₅ (BO₃ )₃ F phosphor doped with Dy(3+) as activator was prepared by the modified solid-state reaction. Formation of the compound was confirmed by use of X-ray powder diffraction. The X-ray powder diffraction pattern of the as-prepared compound shows a good match with the available JCPDS data. The γ-irradiated Mg₅ (BO₃ )₃ F:Dy(3+) phosphor shows a simple glow curve peaking at about 148°C indicating that only one type of trap is being activated within a particular temperature range. The kinetic parameters, including activation energy and frequency factor were determined using Chen's method. The activation energy and frequency factors were 0.75 eV and 4.508 × 10(9) /s respectively. The Z(eff) ofMg₅ (BO₃ )₃ F:Dy(3+) phosphor was 9.84.

  4. Cassava starch maltodextrinization/monomerization through thermopressurized aqueous phosphoric acid hydrolysis.

    PubMed

    Fontana, J D; Passos, M; Baron, M; Mendes, S V; Ramos, L P

    2001-01-01

    Kinetic conditions were established for the depolymerization of cassava starch for the production of maltodextrins and glucose syrups. Thin-layer chromatography and high-performance liquid chromatography analyses corroborated that the proper H3PO4 strength and thermopressurization range (e.g., 142-170 degrees C; 2.8-6.8 atm) can be successfully explored for such hydrolytic purposes of native starch granules. Because phosphoric acid can be advantageously maintained in the hydrolysate and generates, after controlled neutralization with ammonia, the strategic nutrient triplet for industrial fermentations (C, P, N), this pretreatment strategy can be easily recognized as a recommended technology for hydrolysis and upgrading of starch and other plant polysaccharides. Compared to the classic catalysts, the mandatory desalting step (chloride removal by expensive anion-exchange resin or sulfate precipitation as the calcium-insoluble salt) can be avoided. Furthermore, properly diluted phosphoric acid is well known as an allowable additive in several popular soft drinks such as colas since its acidic feeling in the mouth is compatible and synergistic with both natural and artificial sweeteners. Glycosyrups from phosphorolyzed cassava starch have also been upgraded to high-value single-cell protein such as the pigmented yeast biomass of Xanthophyllomyces dendrorhous (Phaffia rhodozyma), whose astaxanthin (diketo-dihydroxy-beta-carotene) content may reach 0.5-1.0 mg/g of dry yeast cell. This can be used as an ideal complement for animal feeding as well as a natural staining for both fish farming (meat) and poultry (eggs). PMID:11963875

  5. Formation of titanium phosphate composites during phosphoric acid decomposition of natural sphene

    SciTech Connect

    Maslova, Marina V.; Rusanova, Daniela Naydenov, Valeri; Antzutkin, Oleg N.; Gerasimova, Lidia G.

    2008-12-15

    Decomposition of mineral sphene, CaTiOSiO{sub 4}, by H{sub 3}PO{sub 4} is investigated in detail. During the dissolution process, simultaneous calcium leaching and formation of titanium phosphate (TiP) take place. The main product of decomposition is a solid titanium phosphate-silica composite. The XRD, solid-sate NMR, IR, TGA, SEM and BET data were used to identify and characterize the composite as a mixture of crystalline Ti(HPO{sub 4}){sub 2}.H{sub 2}O and silica. When 80% phosphoric acid is used the decomposition degree is higher than 98% and calcium is completely transferred into the liquid phase. Formation of Ti(HPO{sub 4}){sub 2}.H{sub 2}O proceeds via formation of meta-stable titanium phosphate phases, Ti(H{sub 2}PO{sub 4})(PO{sub 4}).2H{sub 2}O and Ti(H{sub 2}PO{sub 4})(PO{sub 4}). The sorption affinities of TiP composites were examined in relation to caesium and strontium ions. A decrease of H{sub 3}PO{sub 4} concentration leads to formation of composites with greater sorption properties. The maximum sorption capacity of TiP is observed when 60% H{sub 3}PO{sub 4} is used in sphene decomposition. The work demonstrates a valuable option within the Ti(HPO{sub 4}){sub 2}.H{sub 2}O-SiO{sub 2} composite synthesis scheme, to use phosphoric acid flows for isolation of CaHPO{sub 4}.2H{sub 2}O fertilizer. - Graphical abstract: A new synthesis scheme for preparation of composite titanium phosphate (TiP) ion-exchangers upon one-stage decomposition process of natural sphene with phosphoric acid is presented. Syntheses of {alpha}-TiP-silica composites proceed via formation of meta-stable titanium phosphate phases. The concentration of H{sub 3}PO{sub 4} determines the porosity of final products and their sorption affinities.

  6. Efficacy of sodium hypochlorite, ethylenediaminetetraacetic acid, citric acid and phosphoric acid in calcium hydroxide removal from the root canal: a microscopic cleanliness evaluation.

    PubMed

    da Silva, Juliana Melo; Silveira, Amanda; Santos, Elizandra; Prado, Laiìs; Pessoa, Oscar F

    2011-12-01

    Rooted molars were subjected to standardized canal instrumentation to a master apical file (MAF). The samples were dressed with Ca(OH)(2), and after 7 days, teeth were reopened and Ca(OH)(2) medication was removed by 1 of 4 different experimental procedures: 2.5% sodium hypochlorite (NaOCl) (n = 10); 17% EDTA-T (n = 10); 10% citric acid (n = 10); or 37% phosphoric acid (n = 10). This was followed by reinstrumentation with MAF plus 15 mL saline solution. The roots were prepared for scanning electron microscopic analysis of the cervical, middle, and apical thirds. Statistical analysis was performed with the Kruskal-Wallis test. EDTA-T and phosphoric acid gave the best results in the apical third, with significant statistical differences compared with other groups. NaOCl gave the worst results. Irrigation with 17% EDTA-T and 37% phosphoric acid is more effective than sodium hypochlorite and citric acid in the removal of calcium hydroxide from the apical third.

  7. Process for the removal of acid forming gases from exhaust gases and production of phosphoric acid

    DOEpatents

    Chang, Shih-Ger; Liu, David K.

    1992-01-01

    Exhaust gases are treated to remove NO or NO.sub.x and SO.sub.2 by contacting the gases with an aqueous emulsion or suspension of yellow phosphorous preferably in a wet scrubber. The addition of yellow phosphorous in the system induces the production of O.sub.3 which subsequently oxidizes NO to NO.sub.2. The resulting NO.sub.2 dissolves readily and can be reduced to form ammonium ions by dissolved SO.sub.2 under appropriate conditions. In a 20 acfm system, yellow phosphorous is oxidized to yield P.sub.2 O.sub.5 which picks up water to form H.sub.3 PO.sub.4 mists and can be collected as a valuable product. The pressure is not critical, and ambient pressures are used. Hot water temperatures are best, but economics suggest about 50.degree. C. The amount of yellow phosphorus used will vary with the composition of the exhaust gas, less than 3% for small concentrations of NO, and 10% or higher for concentrations above say 1000 ppm. Similarly, the pH will vary with the composition being treated, and it is adjusted with a suitable alkali. For mixtures of NO.sub.x and SO.sub.2, alkalis that are used for flue gas desulfurization are preferred. With this process, better than 90% of SO.sub.2 and NO in simulated flue gas can be removed. Stoichiometric ratios (P/NO) ranging between 0.6 and 1.5 were obtained.

  8. Quantifying phosphoric acid in high-temperature polymer electrolyte fuel cell components by X-ray tomographic microscopy.

    PubMed

    Eberhardt, S H; Marone, F; Stampanoni, M; Büchi, F N; Schmidt, T J

    2014-11-01

    Synchrotron-based X-ray tomographic microscopy is investigated for imaging the local distribution and concentration of phosphoric acid in high-temperature polymer electrolyte fuel cells. Phosphoric acid fills the pores of the macro- and microporous fuel cell components. Its concentration in the fuel cell varies over a wide range (40-100 wt% H3PO4). This renders the quantification and concentration determination challenging. The problem is solved by using propagation-based phase contrast imaging and a referencing method. Fuel cell components with known acid concentrations were used to correlate greyscale values and acid concentrations. Thus calibration curves were established for the gas diffusion layer, catalyst layer and membrane in a non-operating fuel cell. The non-destructive imaging methodology was verified by comparing image-based values for acid content and concentration in the gas diffusion layer with those from chemical analysis.

  9. IN-VITRO FORMATION OF PYROMORPHITE VIA REACTION OF PB SOURCES WITH SOFT-DRINK PHOSPHORIC ACID

    EPA Science Inventory

    The risk of Pb adsorption into the body may be greatly diminished when accompanied by a phosphate sink. One of the most labile, albeit not healthiest, forms of phosphate consumed in the human diet is derived from cola soft drinks that use phosphoric acid as a preservative and als...

  10. Efficacy of fungicide combinations, phosphoric acid, and plant extract from stinging nettle on potato late blight management and tuber yield

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Late blight, caused by Phytophthora infestans is a major constraint to potato production. Inadequate management of the disease has often resulted in heavy losses in various production regions. We assessed the efficacy of fungicides, phosphoric acid, and stinging nettle plant extract combinations for...

  11. Effect of EDTA and Phosphoric Acid Pretreatment on the Bonding Effectiveness of Self-Etch Adhesives to Ground Enamel

    PubMed Central

    Ibrahim, Ihab M.; Elkassas, Dina W.; Yousry, Mai M.

    2010-01-01

    Objectives: This in vitro study determined the effect of enamel pretreatment with phosphoric acid and ethylenediaminetetraacetic acid (EDTA) on the bond strength of strong, intermediary strong, and mild self-etching adhesive systems. Methods: Ninety sound human premolars were used. Resin composite cylinders were bonded to flat ground enamel surfaces using three self-etching adhesive systems: strong Adper Prompt L-Pop (pH=0.9–1.0), intermediary strong AdheSE (pH=1.6–1.7), and mild Frog (pH=2). Adhesive systems were applied either according to manufacturer instructions (control) or after pretreatment with either phosphoric acid or EDTA (n=10). After 24 hours, shear bond strength was tested using a universal testing machine at a cross-head speed of 0.5 mm/minute. Ultra-morphological characterization of the surface topography and resin/enamel interfaces as well as representative fractured enamel specimens were examined using scanning electron microscopy (SEM). Results: Neither surface pretreatment statistically increased the mean shear bond strength values of either the strong or the intermediary strong self-etching adhesive systems. However, phosphoric acid pretreatment significantly increased the mean shear bond strength values of the mild self-etching adhesive system. SEM examination of enamel surface topography showed that phosphoric acid pretreatment deepened the same etching pattern of the strong and intermediary strong adhesive systems but converted the irregular etching pattern of the mild self-etching adhesive system to a regular etching pattern. SEM examination of the resin/enamel interface revealed that deepening of the etching pattern was consistent with increase in the length of resin tags. EDTA pretreatment had a negligible effect on ultra-morphological features. Conclusions: Use of phosphoric acid pretreatment can be beneficial with mild self-etching adhesive systems for bonding to enamel. PMID:20922162

  12. Gas diffusion electrode setup for catalyst testing in concentrated phosphoric acid at elevated temperatures

    SciTech Connect

    Wiberg, Gustav K. H. E-mail: m.arenz@chem.ku.dk; Fleige, Michael; Arenz, Matthias E-mail: m.arenz@chem.ku.dk

    2015-02-15

    We present a detailed description of the construction and testing of an electrochemical cell setup allowing the investigation of a gas diffusion electrode containing carbon supported high surface area catalysts. The setup is designed for measurements in concentrated phosphoric acid at elevated temperature, i.e., very close to the actual conditions in high temperature proton exchange membrane fuel cells (HT-PEMFCs). The cell consists of a stainless steel flow field and a PEEK plastic cell body comprising the electrochemical cell, which exhibits a three electrode configuration. The cell body and flow field are braced using a KF-25 vacuum flange clamp, which allows an easy assembly of the setup. As demonstrated, the setup can be used to investigate temperature dependent electrochemical processes on high surface area type electrocatalysts, but it also enables quick screening tests of HT-PEMFC catalysts under realistic conditions.

  13. Trial operation of a phosphoric acid fuel cell (PC25) for CHP applications in Europe

    SciTech Connect

    Uhrig, M.; Droste, W.; Wolf, D.

    1996-12-31

    In Europe, ten 200 kW phosphoric acid fuel cells (PAFCs) produced by ONSI (PC25) are currently in operation. Their operators collaborate closely in the European Fuel Cell Users Group (EFCUG). The experience gained from trial operation by the four German operators - HEAG, HGW/HEW, Thyssengas and Ruhrgas - coincides with that of the other European operators. This experience can generally be regarded as favourable. With a view to using fuel cells in combined heat and power generation (CHP), the project described in this report, which was carried out in cooperation with the municipal utility of Bochum and Gasunie of the Netherlands, aimed at gaining experience with the PC 25 in field operation under the specific operating conditions prevailing in Europe. The work packages included heat-controlled operation, examination of plant behavior with varying gas properties and measurement of emissions under dynamic load conditions. The project received EU funding under the JOULE programme.

  14. Evaluation of gas cooling for pressurized phosphoric acid fuel cell stacks

    NASA Technical Reports Server (NTRS)

    Farooque, M.; Skok, A. J.; Maru, H. C.; Kothmann, R. E.; Harry, R. W.

    1983-01-01

    Gas cooling is a more reliable, less expensive and a more simple alternative to conventional liquid cooling for heat removal from the phosphoric acid fuel cell (PAFC). The feasibility of gas cooling has already been demonstrated in atmospheric pressure stacks. This paper presents theoretical and experimental investigation of gas cooling for pressurized PAFC. Two approaches to gas cooling, Distributed Gas Cooling (DIGAS) and Separated Gas Cooling (SGC) were considered, and a theoretical comparison on the basis of cell performance indicated SGC to be superior to DIGAS. The feasibility of SGC was experimentally demonstrated by operating a 45-cell stack for 700 hours at pressure, and determining thermal response and the effect of other related parameters.

  15. Evaluation of Gas-Cooled Pressurized Phosphoric Acid Fuel Cells for Electric Utility Power Generation

    NASA Technical Reports Server (NTRS)

    Faroque, M.

    1983-01-01

    Gas cooling is a more reliable, less expensive and a more simple alternative to conventional liquid cooling for heat removal from the phosphoric acid fuel cell (PAFC). The feasibility of gas-cooling was already demonstrated in atmospheric pressure stacks. Theoretical and experimental investigations of gas-cooling for pressurized PAFC are presented. Two approaches to gas cooling, Distributed Gas-Cooling (DIGAS) and Separated Gas-Cooling (SGC) were considered, and a theoretical comparison on the basis of cell performance indicated SGC to be superior to DIGAS. The feasibility of SGC was experimentally demonstrated by operating a 45-cell stack for 700 hours at pressure, and determining thermal response and the effect of other related parameters.

  16. Analysis and evaluation of the possibility of introducing phosphoric acid fuel cells

    NASA Astrophysics Data System (ADS)

    1991-03-01

    Each step in the manufacture of fuel cells is reviewed. The possibility of cost reduction in the process is investigated. Additionally, the feasibility of providing financial assistance for fuel cell buyers is investigated. Also, the present status and the future outlook of fuel cell development are discussed. In Japan, phosphoric acid fuel cells are beginning demonstration testing. A 200 kW test plant, for commercial and remote island use, has finished its demonstration test favorably. The test run of an 11 mW plant, for the production of electric power, is being conducted by a private company. The manufacture of each of the fuel cell's subsystems is semi-automated at this time. The costs are estimated to be reduced to 60 - 80 percent of the present costs in a 10 mW/year plant and TO 50 - 60 percent of the present costs in a 100 mW/year plant.

  17. Assessment and comparison of 100-MW coal gasification phosphoric acid fuel cell power plants

    NASA Technical Reports Server (NTRS)

    Lu, Cheng-Yi

    1988-01-01

    One of the advantages of fuel cell (FC) power plants is fuel versatility. With changes only in the fuel processor, the power plant will be able to accept a variety of fuels. This study was performed to design process diagrams, evaluate performance, and to estimate cost of 100 MW coal gasifier (CG)/phosphoric acid fuel cell (PAFC) power plant systems utilizing coal, which is the largest single potential source of alternate hydrocarbon liquids and gases in the United States, as the fuel. Results of this study will identify the most promising integrated CG/PAFC design and its near-optimal operating conditions. The comparison is based on the performance and cost of electricity which is calculated under consistent financial assumptions.

  18. Flexible and Conducting Carbon Nanofibers Obtained from Electrospun Polyacrylonitrile/Phosphoric Acid Nanofibers.

    PubMed

    Lim, Baek Ho; Nirmala, R; Navamathavan, R; Kim, Hak Yong

    2016-01-01

    We report on the feasible synthesis of flexible and conductive carbon nanofibers by electrospinning process using polyacrylonitrile (PAN) and phosphoric acid (PA) as precursors. The carbon nanofibers were subsequently obtained by stabilization and carbonization of the electrospun PAN nanofibers. From SEM data, it was found that the electrospun PAN nanofibers showed a smooth surface and had an average diameter of approximately 200 nm. Afterwards, the electrospun PAN nanofibers were stabilized at 250 °C and heated at 900 °C for the carbonization process to obtain the carbon nanofibers. The carbonized PAN nanofibers exhibited a drastic improvement of electrical conduction. From Raman spectroscopy data, it was found that the carbonization at 900 °C gave a decrease of the intensity ratio of D and G peaks, indicating higher graphitic structure. PMID:27398565

  19. Method for the purification of bis (2-ethyl-hexyl)phosphoric acid

    DOEpatents

    Schulz, W.W.

    1974-02-19

    Foreign products including the neutral organophosphorous compounds and the iron salts normally present in commercial bis(2ethyl-hexyl) phosphoric acid(HDEHP), and the radiolytic degradation products of HDEHP on exposure of HDEHP to beta and gamma irradiation are removed from HDEHP containing one or more of such products by contacting the said foreign product containing HDEHP with a macroreticular anion exchange resin in base form whereby the DEHP- ion of HDEHP exchanges with the anion of the resin and is thus adsorbed on the resin and the said foreign products are not adsorbed and will pass through a bed of particles of the resin. The adsorbed DEHP- ion is then eluted from the resin and acidified to form and recover the purified HDEHP. (auth)

  20. Phosphoric acid pretreatment of Achyranthes aspera and Sida acuta weed biomass to improve enzymatic hydrolysis.

    PubMed

    Siripong, Premjet; Duangporn, Premjet; Takata, Eri; Tsutsumi, Yuji

    2016-03-01

    Achyranthes aspera and Sida acuta, two types of weed biomass are abundant and waste in Thailand. We focus on them as novel feedstock for bio-ethanol production because they contain high-cellulose content (45.9% and 46.9%, respectively) and unutilized material. Phosphoric acid (70%, 75%, and 80%) was employed for the pretreatment to improve by enzymatic hydrolysis. The pretreatment process removed most of the xylan and a part of the lignin from the weeds, while most of the glucan remained. The cellulose conversion to glucose was greater for pretreated A. aspera (86.2 ± 0.3%) than that of the pretreated S. acuta (82.2 ± 1.1%). Thus, the removal of hemicellulose significantly affected the efficiency of the enzymatic hydrolysis. The scanning electron microscopy images showed the exposed fibrous cellulose on the cell wall surface, and this substantial change of the surface structure contributed to improving the enzyme accessibility.

  1. Effect of impurities in wet-process phosphoric acids on DAP grades. [Diammonium phosphate

    SciTech Connect

    Achorn, F.P.; Dillard, E.F.; Frazier, A.W.; Salladay, D.G.

    1980-11-01

    Results of this study identify the main problems in meeting diammonium phosphate (DAP) grade specifications and suggest some possible solutions to these problems as follows: 1. The major source of grade deficiency in the commercial samples which were investigated was calcium. Some solutions to this problem are to maintain filter cloths in the phosphoric acid unit in good condition, operate the phosphoric acid unit at as low an acid temperature as consistent with good operation of this unit, and partially clarify the acid before it is used. 2. In the DAP unit the amount of Fe/sub 2/O/sub 3/ and F in the acid affects the content of C.I. P/sub 2/O/sub 5/ in the product. If the F:Fe/sub 2/O/sub 3/ wt ratio in the product can be kept above 2.3:1, probably the C.I.-P/sub 2/O/sub 5/ content of the product will be less than 0.1 percent. At lower F:Fe/sub 2/O/sub 3/ wt ratios, it is advantageous to have low retention times in the preneutralizer and ammoniator-granulator when the N:P mole ratio is 1.4:1 or higher. 3. Other data show that the N:P mole ratio in the slurry from the preneutralizer to the granulator must be above 1.4:1 to avoid nitrogen deficiencies. At lower ratios the product will contain some MAP; this causes nitrogen deficiency in the products. 4. The Mg and Al contents of the acids have less effect on grade deficiency than Ca and Fe. 5. To avoid highly viscous preneutralizer slurries when low preneutralizer retention times are used, ensure that there is sufficient F available (F:Fe/sub 2/O/sub 3/ wt ratio > 2.0:1) to combine with the Fe/sub 2/O/sub 3/ to form coarse crystals. An alternative to this latter suggestion is to replace the preneutralizer with a TVA pipe reactor which is partially installed in the granulator and discharges viscous slurry directly onto the bed of material in the granulator.

  2. Low pH anaerobic digestion of waste activated sludge for enhanced phosphorous release.

    PubMed

    Latif, Muhammad A; Mehta, Chirag M; Batstone, Damien J

    2015-09-15

    This paper assesses anaerobic digestion of waste activated sludge (WAS) at low pH to enhance phosphorous solubility. Batch biochemical methane potential tests were conducted at a pH range of 5 to 7.2 in two separate sets (two different WAS samples collected from municipal WWTP). Low pH (<5.7) caused a significant (p = 0.004) decrease in methane potential (B0) up to 33% and 3.6 times increase in phosphorus release compared to neutral pH (7-7.7), but with no major change in methane production rate coefficient (khyd). The loss in methane yield was mainly due to decrease in hydrolytic capability rather than inhibition of methanogenesis with volatile fatty acids being <300 mgCOD L(-1) and soluble COD <1300 mgCOD L(-1) even at low pH. While pH did not influence the acetoclastic community (Methanosaeta dominated), it was the primary driver for the remaining community (p = 0.004), and caused a loss of diversity and shift to Clostridia.

  3. One-Step Hydrothermal Synthesis of Butanetetracarboxylic Acid-Coated NaYF₄:Yb³⁺, Er³⁺ Upconversion Phosphors with Enhancement Upconversion Luminescence.

    PubMed

    Zhang, Liming; Mao, Lanlan; Lu, Zhuoxuan; Deng, Yan; He, Nongyue

    2016-01-01

    Butanetetracarboxylic acid (BTCA)/NaYF₄:Yb³⁺, Er³⁺ upconversion phosphors have been successfully synthesized by a one-step hydrothermal method. The SEM and XRD results show the as-prepared phosphors exhibit main hexagonal lattice structures and uniform morphologies. FT-IR spectra confirm that the surface of as-prepared phosphors is inherently modified with the carboxyl groups. Under the excitation of 980 nm, it has been observed that BTCA/NaYF₄:Yb³⁺, Er³⁺ upconversion phosphors have a higher upconversion luminescence efficiency than that coated with citrate, ethylenediamine tetraacetic acid (EDTA), or polyacrylic acid (PAA). These results indicate that the BTCA/NaYF₄:Yb³⁺, Er³⁺ phosphors may have superior optical properties, and thus have great potential for biological applications. PMID:27398591

  4. A Comparative Study of Phosphoric Acid-doped m-PBI Membranes

    SciTech Connect

    Perry, Kelly A; More, Karren Leslie; Payzant, E Andrew; Meisner, Roberta A; Sumpter, Bobby G; Benicewicz, Brian

    2014-01-01

    Phosphoric acid (PA)-doped m-polybenzimidazole (PBI) membranes used in high temperature fuel cells and hydrogen pumps were prepared by a conventional imbibing process and a sol-gel fabrication process. A comparative study was conducted to investigate the critical properties of PA doping levels, ionic conductivities, mechanical properties, and molecular ordering. This systematic study found that sol-gel PA-doped m-PBI membranes were able to absorb higher acid doping levels and to achieve higher ionic conductivities than conventionally imbibed membranes when treated in an equivalent manner. Even at similar acid loadings, the sol-gel membranes exhibited higher ionic conductivities. Heat treatment of conventionally imbibed membranes with 29wt% solids caused a significant reduction in mechanical properties; conversely, sol-gel membranes exhibited an enhancement in mechanical properties. From X-ray structural studies and atomistic simulations, both conventionally imbibed and sol-gel membranes exhibited d-spacings of 3.5 and 4.6 , which were tentatively attributed to parallel ring stacking and staggered side-to-side packing, respectively, of the imidazole rings in these aromatic hetercyclic polymers. An anisotropic staggered side-to-side chain packing present in the conventional membranes may be root to the reduction in mechanical properties.

  5. Luminescence characteristics of Dy3+ activated Na 2Sr 2Mg (BO 3)2F 2: Dy 3+ phosphor

    NASA Astrophysics Data System (ADS)

    Wani, Javaid A.; Dhoble, N. S.; Dhoble, S. J.

    2012-11-01

    In this paper, we have reported a new Na 2Sr 2Mg (BO 3)2F 2:Dy 3+ thermoluminescence (TL) phosphor prepared via the wet chemical method. Prepared phosphor was characterized by X-ray powder diffraction, photoluminescence (PL), TL and scanning electronmicroscopy techniques. The scanning electronmicroscopic image of Na 2Sr 2Mg (BO 3)2F 2:Dy 3+ phosphor confirms the micron size of particles. Under the PL study, the characteristic emission spectrum of Dy 3+ corresponding to 4F 9/2→6H 15/2 (481 nm) and 4F 9/2→6H 13/2 (576 nm) transitions was observed. The TL property of the as prepared phosphor was also found to be good. TL intensity of Na 2Sr2Mg(BO 3)F 2:Dy 3+ phosphors at 0.99 kGy exposure of γ-irradiations was compared with standard CaSO 4:Dy phosphor. It was seen that TL intensity of Na 2Sr 2Mg (BO 3)2F 2: Dy 3+ phosphors is 1.1 times less compared with the standard CaSO 4:Dy TL dosimeter phosphor. The kinetic parameters are also discussed in detail. The values of activation energy E (eV) and frequency factor S (s -1) were found to be 0.57 eV and 1.25×106 s-1, respectively.

  6. Radiological, chemical and morphological characterizations of phosphate rock and phosphogypsum from phosphoric acid factories in SW Spain.

    PubMed

    Rentería-Villalobos, Marusia; Vioque, Ignacio; Mantero, Juan; Manjón, Guillermo

    2010-09-15

    In this work, radiological, chemical, and also morphological characterization was performed in phosphate rock and phosphogypsum samples, in order to understand the behavior of toxic elements. Characterization was carried out using X-ray diffraction (XRD), X-ray fluorescence (XRF), gamma spectrometry and scanning electron microscopy with energy-dispersive X-ray analysis (SEM-EDX). Our results show that the phosphate rock was mainly composed of fluorapatite, calcite, perovskite, quartz, magnetite, pyrite and kaolinite, whereas phosphogypsum only exhibited dihydrated calcium sulfate. The activity concentration of U-series radioisotopes in phosphate rock was around 1640 Bq/kg. (226)Ra and (210)Pb tend to be distributed into phosphogypsum by up to 80%, whereas the fraction of U-isotopes is 10%. The most abundant trace elements in phosphate rock were Sr, Cr, V, Zn, Y, Ni and Ba. Some elements, such as Ba, Cd, Cu, La, Pb, Se, Sr, Th and Y, were enriched in the phosphogypsum. This enrichment may be attributed to an additional input associated to the sulfuric acid used for the phosphoric acid production. Furthermore, results from SEM-EDX demonstrated that toxic elements are not distributed homogeneously into phosphogypsum. Most of these elements are concentrated in particles <20 microm of high porosity, and could be easily mobilized by leaching and/or erosion.

  7. Radiological, chemical and morphological characterizations of phosphate rock and phosphogypsum from phosphoric acid factories in SW Spain.

    PubMed

    Rentería-Villalobos, Marusia; Vioque, Ignacio; Mantero, Juan; Manjón, Guillermo

    2010-09-15

    In this work, radiological, chemical, and also morphological characterization was performed in phosphate rock and phosphogypsum samples, in order to understand the behavior of toxic elements. Characterization was carried out using X-ray diffraction (XRD), X-ray fluorescence (XRF), gamma spectrometry and scanning electron microscopy with energy-dispersive X-ray analysis (SEM-EDX). Our results show that the phosphate rock was mainly composed of fluorapatite, calcite, perovskite, quartz, magnetite, pyrite and kaolinite, whereas phosphogypsum only exhibited dihydrated calcium sulfate. The activity concentration of U-series radioisotopes in phosphate rock was around 1640 Bq/kg. (226)Ra and (210)Pb tend to be distributed into phosphogypsum by up to 80%, whereas the fraction of U-isotopes is 10%. The most abundant trace elements in phosphate rock were Sr, Cr, V, Zn, Y, Ni and Ba. Some elements, such as Ba, Cd, Cu, La, Pb, Se, Sr, Th and Y, were enriched in the phosphogypsum. This enrichment may be attributed to an additional input associated to the sulfuric acid used for the phosphoric acid production. Furthermore, results from SEM-EDX demonstrated that toxic elements are not distributed homogeneously into phosphogypsum. Most of these elements are concentrated in particles <20 microm of high porosity, and could be easily mobilized by leaching and/or erosion. PMID:20537794

  8. Mechanistic insights into a BINOL-derived phosphoric acid-catalyzed asymmetric Pictet-Spengler reaction.

    PubMed

    Overvoorde, Lois M; Grayson, Matthew N; Luo, Yi; Goodman, Jonathan M

    2015-03-01

    The reaction of tryptamine and (2-oxocyclohexyl)acetic acid can be catalyzed by 3,3'-bis(triphenylsilyl)-1,1'-bi-2-naphthol phosphoric acid to give an asymmetric β-carboline. This reaction was first studied by Holloway et al. ( Org. Lett. 2010 , 12 , 4720 - 4723 ), but their mechanistic work did not explain the high stereoselectivity achieved. This study uses density functional theory and hybrid quantum mechanics/molecular mechanics calculations to investigate this reaction and provide a model to explain its outcome. The step leading to diastereo- and enantioselectivity is an asymmetric Pictet-Spengler reaction involving an N-acyliminium ion bound to the catalyst in a bidentate fashion. This interaction occurs via hydrogen bonds between the two terminal oxygen atoms of the catalyst phosphate group and the hydrogen atoms at N and C2 of the substrate indole group. These bonds hold the transition structure rigidly and thus allow the catalyst triphenylsilyl groups to influence the enantioselectivity. PMID:25654215

  9. Organic-inorganic interaction between hydroxyapatite and gelatin with the aging of gelatin in aqueous phosphoric acid solution.

    PubMed

    Chang, Myung Chul

    2008-11-01

    Hydroxyapatite (HAp)/gelatin (GEL) nanocomposite was prepared by the solution-precipitation process using Ca(OH)(2) in water and aqueous solution of H(3)PO(4) in GEL. Before the co precipitation process the GEL powders were dissolved in the aqueous phosphoric acid solution for the phosphorylation of GEL molecules. The chemical variation of the phosphorylated GEL macromolecules was investigated by using attenuated total reflection (ATR) measurement. The crystal growth of HAp became bigger with the long-time aging of the GEL molecules in the phosphoric acid solution, and it resulted from the reduction of length scale of the GEL molecules. The degree of the organic-inorganic interaction was decreased because of the degradation of the GEL macromolecules.

  10. Enantiodivergent Atroposelective Synthesis of Chiral Biaryls by Asymmetric Transfer Hydrogenation: Chiral Phosphoric Acid Catalyzed Dynamic Kinetic Resolution.

    PubMed

    Mori, Keiji; Itakura, Tsubasa; Akiyama, Takahiko

    2016-09-12

    Reported herein is an enantiodivergent synthesis of chiral biaryls by a chiral phosphoric acid catalyzed asymmetric transfer hydrogenation reaction. Upon treatment of biaryl lactols with aromatic amines and a Hantzsch ester in the presence of chiral phosphoric acid, dynamic kinetic resolution (DKR) involving a reductive amination reaction proceeded smoothly to furnish both R and S isomers of chiral biaryls with excellent enantioselectivities by proper choice of hydroxyaniline derivative. This trend was observed in wide variety of substrates, and various chiral biphenyl and phenyl naphthyl adducts were synthesized with satisfactory enantioselectivities in enantiodivergent fashion. The enantiodivergent synthesis of synthetically challenging, chiral o-tetrasubstituted biaryls were also accomplished, and suggests high synthetic potential of the present method. PMID:27491630

  11. Low thermal budget n-type doping into Ge(001) surface using ultraviolet laser irradiation in phosphoric acid solution

    NASA Astrophysics Data System (ADS)

    Takahashi, Kouta; Kurosawa, Masashi; Ikenoue, Hiroshi; Sakashita, Mitsuo; Takeuchi, Wakana; Nakatsuka, Osamu; Zaima, Shigeaki

    2016-02-01

    We have investigated phosphorus (P) doping into Ge(001) surfaces by using ultraviolet laser irradiation in phosphoric acid solution at room temperature. We demonstrated that the diffusion depth of P in Ge and the concentration of electrically activated P can be controlled by the number of laser shots. Indeed, a high concentration of electrically activated P of 2.4 × 1019 cm-3 was realized by 1000-times laser shots at a laser energy of 1.0 J/cm2, which is comparable or better than the counterparts of conventional n-type doping using a high thermal budget over 600 °C. The generation current is dominant in the reverse bias condition for the laser-doped pn-junction diodes independent on the number of laser shots, thus indicating low-damage during the pn-junction formation. These results open up the possibility for applicable low thermal budget doping process for Ge-based devices fabricated on flexible substrates as well as Si electronics.

  12. Measurement of activity distribution using photostimulable phosphor imaging plates in decommissioned 10 MV medical linear accelerator.

    PubMed

    Fujibuchi, Toshioh; Yonai, Shunsuke; Yoshida, Masahiro; Sakae, Takeji; Watanabe, Hiroshi; Abe, Yoshihisa; Itami, Jun

    2014-08-01

    Photonuclear reactions generate neutrons in the head of the linear accelerator. Therefore, some parts of the linear accelerator can become activated. Such activated materials must be handled as radioactive waste. The authors attempted to investigate the distribution of induced radioactivity using photostimulable phosphor imaging plates. Autoradiographs were produced from some parts of the linear accelerator (the target, upper jaw, multileaf collimator and shielding). The levels of induced radioactivity were confirmed to be non-uniform within each part from the autoradiographs. The method was a simple and highly sensitive approach to evaluating the relative degree of activation of the linear accelerators, so that appropriate materials management procedures can be carried out.

  13. Uranium control in phosphogypsum. [In wet-process phosphoric acid production

    SciTech Connect

    Hurst, F.J.; Arnold, W.D.

    1980-01-01

    In wet-process phosphoric acid plants, both previous and recent test results show that uranium dissolution from phosphate rock is significantly higher when the rock is acidulated under oxidizing conditions than under reducing conditions. Excess sulfate and excess fluoride further enhance the distribution of uranium to the cake. Apparently the U(IV) present in the crystal lattice of the apatite plus that formed by reduction of U(IV) by FE(II) during acidulation is trapped or carried into the crystal lattice of the calcium sulfate crystals as they form and grow. The amount of uranium that distributes to hemihydrate filter cake is up to seven times higher than the amount that distributes to the dihydrate cake. About 60% of the uranium in hemihydrate cakes can be readily leached after hydration of the cake, but the residual uranium (20 to 30%) is very difficult to remove economically. Much additional research is needed to develop methods for minimizing uranium losses to calcium filter cakes.

  14. Absorption of sulfur dioxide from simulated flue gas by polyethyleneimine-phosphoric acid solution.

    PubMed

    Bo, Wen; Li, Hongxia; Zhang, Junjie; Song, Xiangjia; Hu, Jinshan; Liu, Ce

    2016-12-01

    Clean fuel technologies have been widely developed in current society because fuel combustion can directly bring about the emission of hazardous gasses such as SO2. Flue gas desulfurization by polyethyleneimine (PEI)-phosphoric acid solution is an efficient desulfurization method. In this research, the PEI and the additive H3PO4 were used as absorption solution. SO2 was absorbed by the system and desorbed from the loaded solution. The cycle operation was also analyzed. Some technology conditions such as the concentration of PEI, the temperature, the gas flow rate, the concentration of SO2 and the pH value were experimentally researched. With the optimized process, the absorption efficiency of this system could reach 98% and the desorption efficiency was over 60%, showing good absorption/desorption capability. With this efficient approach, the present study may open a new window for developing high-performance absorbents which can make SO2 be well desorbed from the loaded solution and better reused in the flue gas desulfurization. PMID:27082307

  15. Conversion of spent solid phosphoric Acid catalyst to environmentally friendly fertilizer.

    PubMed

    Merwe, Werner van der

    2010-03-01

    Solid phosphoric acid (SPA) catalysts are widely used in the petroleum industry. Despite a high phosphorus content the spent catalyst is generally not reused. Moreover, due to the limited life spans that are achieved industrially, large quantities of spent catalyst requires disposal, often by landfill. SPA can be readily converted to fertilizer, but the presence of carbonaceous deposits on the catalyst presents a potential environmental hazard. This work demonstrates that these deposits are mostly polyaromatic (amorphous carbon) with smaller amounts of oxygenates and aliphatics. Neither the chemical makeup nor the physical structure of the catalyst or the presence of coke precludes it from use as fertilizer. Subsequently, the spent catalyst was milled, neutralized with lime and ammonium hydroxide, and then calcined to yield a phosphate-rich fertilizer. Toxicity characteristic leaching tests of the spent catalyst fertilizer showed low levels of metals and organics, establishing that no harmful compounds are likely to be absorbed into plant life or groundwater. A plant growth study of the spent catalyst fertilizer indicated that it is approximately as effective as superphosphate fertilizer when used in alkaline soil. The spent catalyst fertilizer is environmentally benign and economically efficient.

  16. Electrochemical behavior of lead alloys in sulfuric and phosphoric acid solutions

    NASA Astrophysics Data System (ADS)

    Paleska, I.; Pruszkowska-Drachal, R.; Kotowski, J.; Dziudzi, A.; Milewski, J. D.; Kopczyk, M.; Czerwiński, A.

    The electrochemical behavior of lead, lead-antimony, and lead-calcium-aluminium-tin alloys has been studied in solutions containing various concentrations of sulfuric and phosphoric acids. The dependence of these electrode processes on some experimental conditions (mainly sweep rate and potential range) has been studied. The measurements were performed using a cyclic voltammetry technique. The study and the analysis of the morphology of alloys have been performed using a scanning electron microscope (SEM). Cyclic voltammograms of the lead-antimony alloy electrodes, similarly to pure lead electrode, also show the "anodic excursion" peak under some experimental conditions. Well defined current waves, corresponding to the oxidation and reduction processes of Sb, are observed, if the alloy surface is freshly abraded. The oxidation of antimony starts at potentials at which the formation of PbO takes place. The peak current of Sb oxidation reaction decreases during successive cycles, suggesting that Sb dissolves from the alloy surface during the first CV sweeps. Another explanation for this effect might be the formation of a PbSO 4 selective membrane.

  17. Conversion of spent solid phosphoric Acid catalyst to environmentally friendly fertilizer.

    PubMed

    Merwe, Werner van der

    2010-03-01

    Solid phosphoric acid (SPA) catalysts are widely used in the petroleum industry. Despite a high phosphorus content the spent catalyst is generally not reused. Moreover, due to the limited life spans that are achieved industrially, large quantities of spent catalyst requires disposal, often by landfill. SPA can be readily converted to fertilizer, but the presence of carbonaceous deposits on the catalyst presents a potential environmental hazard. This work demonstrates that these deposits are mostly polyaromatic (amorphous carbon) with smaller amounts of oxygenates and aliphatics. Neither the chemical makeup nor the physical structure of the catalyst or the presence of coke precludes it from use as fertilizer. Subsequently, the spent catalyst was milled, neutralized with lime and ammonium hydroxide, and then calcined to yield a phosphate-rich fertilizer. Toxicity characteristic leaching tests of the spent catalyst fertilizer showed low levels of metals and organics, establishing that no harmful compounds are likely to be absorbed into plant life or groundwater. A plant growth study of the spent catalyst fertilizer indicated that it is approximately as effective as superphosphate fertilizer when used in alkaline soil. The spent catalyst fertilizer is environmentally benign and economically efficient. PMID:20146419

  18. Fluoride removal from groundwater by limestone treatment in presence of phosphoric acid.

    PubMed

    Gogoi, Sweety; Nath, Suresh K; Bordoloi, Shreemoyee; Dutta, Robin K

    2015-04-01

    Fluoride removal from groundwater has been studied by addition of dilute phosphoric acid (PA) to the influent water before limestone treatment through laboratory plug-flow column experiments and bench-scale plug-flow pilot tests. In this PA-enhanced limestone defluoridation (PAELD) technique, fluoride is removed from 0.526 mM to 0.50-52.60 μM in 3 h with near neutral final pH. The presence of PA increases the fluoride removal capacity of limestone to 1.10 mg/g compared to 0.39 mg/g reported in its absence. The changes in fluoride removal with variation in initial PA concentration, initial fluoride concentration and the final pH have been found to be statistically significant with p < 0.05. The estimated recurring cost is US$ ≈0.58/m(3) water. Simple scrubbing and rinsing is a preferable method for regeneration of limestone as it is almost equally effective with lime or NaOH. Sorption of fluoride by calcium phosphates produced in situ in the reactor is the dominant mechanism of fluoride removal in the PAELD. Precipitation of CaF2 and sorption of fluoride by the limestone also contribute to the fluoride removal. High efficiency, capacity, safety, environment-friendliness, low cost and simplicity of operation make the PAELD a potential technique for rural application. PMID:25621387

  19. Advanced water-cooled phosphoric acid fuel cell development. Final report

    SciTech Connect

    Not Available

    1992-09-01

    This program was conducted to improve the performance and minimize the cost of existing water-cooled phosphoric acid fuel cell stacks for electric utility and on-site applications. The goals for the electric utility stack technology were a power density of at least 175 watts per square foot over a 40,000-hour useful life and a projected one-of-a-kind, full-scale manufactured cost of less than $400 per kilowatt. The program adapted the existing on-site Configuration-B cell design to electric utility operating conditions and introduced additional new design features. Task 1 consisted of the conceptual design of a full-scale electric utility cell stack that meets program objectives. The conceptual design was updated to incorporate the results of material and process developments in Tasks 2 and 3, as well as results of stack tests conducted in Task 6. Tasks 2 and 3 developed the materials and processes required to fabricate the components that meet the program objectives. The design of the small area and 10-ft{sup 2} stacks was conducted in Task 4. Fabrication and assembly of the short stacks were conducted in Task 5 and subsequent tests were conducted in Task 6. The management and reporting functions of Task 7 provided DOE/METC with program visibility through required documentation and program reviews. This report describes the cell design and development effort that was conducted to demonstrate, by subscale stack test, the technical achievements made toward the above program objectives.

  20. Experimental oxygen isotope fractionation between siderite-water and phosphoric acid liberated CO2-siderite

    USGS Publications Warehouse

    Carothers, W.W.; Adami, L.H.; Rosenbauer, R.J.

    1988-01-01

    The equilibrium fractionation of O isotopes between synthetic siderite and water has been measured at temperatures ranging from 33?? to 197??C. The fractionation between siderite and water over this temperature range can be represented by the equation: 103 ln ?? = 3.13 ?? 106T-2 - 3.50. Comparison between the experimental and theoretical fractionations is favorable only at approximately 200??C; at lower temperatures, they generally differ by up to 2 permil. Siderite was prepared by the slow addition of ferrous chloride solutions to sodium bicarbonate solutions at the experimental temperatures. It was also used to determine the O isotope fractionation factors between phosphoric acid liberated CO2 and siderite. The fractionation factors for this pair at 25?? and 50??C are 1.01175 and 1.01075, respectively. Preliminary results of the measured C isotope fractionation between siderite and Co2 also indicate C isotopic equilibrium during precipitation of siderite. The measured distribution of 13C between siderite and CO2 coincides with the theoretical values only at about 120??C. Experimental and theoretical C fractionations differ up to 3 permil at higher and lower temperatures. ?? 1988.

  1. Immunohistochemical and ultrastructural evaluation of the effects of phosphoric acid etching on dentin proteoglycans.

    PubMed

    Oyarzún, A; Rathkamp, H; Dreyer, E

    2000-12-01

    It has been reported that phosphoric acid (PA) produces structural and molecular alterations in dentin collagen fibrils; however, no relevant information exists on the influence of etching with PA on dentin non-collagenous macromolecules. The present study investigated, by immunohistochemistry and ultrastructural histochemistry, the behavior of dentin proteoglycans (PG) after etching human dentin samples with 35% PA gel (thickened with colloidal silica) or with a 35% PA liquid for 15, 30 and 120 s. Immunolabeling with a mouse monoclonal anti-chondroitin sulfate antibody demonstrated that glycosaminoglycans (GAG) were preserved within dentinal tubules opened to the surface after etching with PA gel. In addition, the cationic tracer polyethyleneimine, used for the ultramicroscopic localization of PG anionic sites, revealed that treatment of dentin samples with PA gel preserved the polyanionic peritubular PG in the etched area. On the other hand, etching with the PA liquid produced loss of peritubular GAG and PG anionic sites in the etched dentin surface. The results obtained indicated that similar concentrations of PA in gel or liquid formulations differently affect the organization of dentin PG. The clinical significance of these in vitro findings and the structural and molecular interactions of dentin PG with adhesive systems are still unknown.

  2. Fluoride removal from groundwater by limestone treatment in presence of phosphoric acid.

    PubMed

    Gogoi, Sweety; Nath, Suresh K; Bordoloi, Shreemoyee; Dutta, Robin K

    2015-04-01

    Fluoride removal from groundwater has been studied by addition of dilute phosphoric acid (PA) to the influent water before limestone treatment through laboratory plug-flow column experiments and bench-scale plug-flow pilot tests. In this PA-enhanced limestone defluoridation (PAELD) technique, fluoride is removed from 0.526 mM to 0.50-52.60 μM in 3 h with near neutral final pH. The presence of PA increases the fluoride removal capacity of limestone to 1.10 mg/g compared to 0.39 mg/g reported in its absence. The changes in fluoride removal with variation in initial PA concentration, initial fluoride concentration and the final pH have been found to be statistically significant with p < 0.05. The estimated recurring cost is US$ ≈0.58/m(3) water. Simple scrubbing and rinsing is a preferable method for regeneration of limestone as it is almost equally effective with lime or NaOH. Sorption of fluoride by calcium phosphates produced in situ in the reactor is the dominant mechanism of fluoride removal in the PAELD. Precipitation of CaF2 and sorption of fluoride by the limestone also contribute to the fluoride removal. High efficiency, capacity, safety, environment-friendliness, low cost and simplicity of operation make the PAELD a potential technique for rural application.

  3. Surface properties and early murine pre-osteoblastic cell responses of phosphoric acid modified titanium surface

    PubMed Central

    Osathanon, Thanaphum; Sawangmake, Chenphop; Ruangchainicom, Nanticha; Wutikornwipak, Pavitra; Kantukiti, Panisa; Nowwarote, Nunthawan; Pavasant, Prasit

    2015-01-01

    Aims The present study investigated the surface properties and murine pre-osteoblast cell (MC3T3-E1) responses of phosphoric acid (H3PO4) treated commercially pure titanium. Methods Titanium discs were treated with various concentration of H3PO4 (5%, 10%, and 20%; v/v) at 90 °C for 30 min. Surface properties were evaluated by profilometer, contact angle meter, and scanning electron microscopy (SEM) with energy dispersive X-rays. MC3T3-E1 attachment and spreading were evaluated by SEM and phalloidin immunohistochemistry staining. Results Surface roughness and wettability were not statistically difference among all experimental and control groups. Phosphate and oxygen were detected on H3PO4 treated surfaces. At 20 min, cell attachment was significantly higher in 10% and 20% H3PO4 treated groups compared to the control. Cells exhibited orientated-cytoskeleton fibers on 20% H3PO4 modified titanium surface. Though, there was no difference in cell spreading stage among all treatment groups. Conclusion H3PO4 treatment on titanium may influence early cell response, particularly on attachment and spreading. PMID:26937362

  4. Extraction of cellulose nano-crystals from old corrugated container fiber using phosphoric acid and enzymatic hydrolysis followed by sonication.

    PubMed

    Tang, Yanjun; Shen, Xiaochuang; Zhang, Junhua; Guo, Daliang; Kong, Fangong; Zhang, Nan

    2015-07-10

    Due to its amazing physicochemical properties and high environmental compatibility, cellulose nano-crystals (CNC) hold great promise for serving as a strategic platform for sustainable development. Now, there has been growing interest in the development of processes using waste or residual biomass as CNC source for addressing economic and environmental concerns. In the present work, a combined process involving phosphoric acid hydrolysis, enzymatic hydrolysis and sonication was proposed aiming to efficiently exact CNC from low-cost old corrugated container (OCC) pulp fiber. The effect of enzymatic hydrolysis on the yield and microstructure of resulting CNC was highlighted. Results showed that the enzymatic hydrolysis was effective in enhancing CNC yield after phosphoric acid hydrolysis. CNC was obtained with a yield of 23.98 wt% via the combined process with phosphoric acid concentration of 60 wt%, cellulase dosage of 2 mL (84 EGU) per 2g fiber and sonication intensity of 200 W. Moreover, the presence of enzymatic hydrolysis imparted the obtained CNC with improved dispersion, increased crystallinity and thermal stability.

  5. Rapid prototyping of reflectors for vehicle lighting using laser activated remote phosphor

    NASA Astrophysics Data System (ADS)

    Lachmayer, Roland; Kloppenburg, Gerolf; Wolf, Alexander

    2015-03-01

    Bright white light sources are of significant importance for automotive front lighting systems. Today's upper class vehicles mainly use HID or LED as light source. As a further step in this development laser diode based systems offer high luminance, efficiency and allow the realization of new styling concepts and new dynamic lighting functions. These white laser diode systems can either be realized by mixing different spectral sources or by combining diodes with specific phosphors. Based on the approach of generating light using a laser and remote phosphor, lighting modules are manufactured. Four blue laser diodes (450 nm) are used to activate a phosphor coating and thus to achieve white light. A segmented paraboloid reflector generates the desired light distribution for an additional car headlamp. We use high speed milling and selective laser melting to build the reflector system for this lighting module. We compare the spectral reflection grade of these materials. Furthermore the generated modules are analyzed regarding their efficiency and light distribution. The use of Rapid Prototyping technologies allows an early validation of the chosen concept and is supposed to reduce cost and time in the product development process significantly. Therefor we discuss costs and times of the applied manufacturing technologies.

  6. Eu3+-activated SrMoO4 phosphors for white LEDs applications: Synthesis and structural characterization

    NASA Astrophysics Data System (ADS)

    Shivakumara, C.; Saraf, Rohit

    2015-04-01

    We report the synthesis of Eu3+-activated SrMoO4 phosphors by the facile nitrate-citrate gel combustion method. Powder XRD and Rietveld refinement data confirmed that these phosphors have a monophasic scheelite-type tetragonal structure with space group I41/a (No. 88). FESEM micrographs indicate the agglomerated spherical particles. FTIR spectra showed four stretching and bending vibrational modes (2Au and 2Eu). UV-Visible absorption spectroscopy illustrated that the optical band gap energy (Eg) values increase with increase in Eu3+ concentration. The host SrMoO4 phosphor exhibited an intense blue emission under UV excitation (368 nm). The Eu3+-activated SrMoO4 phosphors revealed characteristic luminescence due to Eu3+ ion corresponding to 5D1 → 7FJ (J = 1, 2) and 5D0 → 7FJ (J = 1, 2, 3, 4) transitions upon 465 nm excitation. The electric dipole transition located at 615 nm (5D0 → 7F2) was stronger than the magnetic dipole transition located at 592 nm (5D0 → 7F1). Intensity parameters (Ω2, Ω4) and radiative properties such as transition probabilities (AT), radiative lifetime (τrad) and branching ratio (β) of Eu3+-activated SrMoO4 phosphors were calculated using the Judd-Ofelt theory. Based on the CIE chromaticity diagram, these phosphors can be promising materials for the development of blue and orange-red component in white LEDs.

  7. Maximum power output and load matching of a phosphoric acid fuel cell-thermoelectric generator hybrid system

    NASA Astrophysics Data System (ADS)

    Chen, Xiaohang; Wang, Yuan; Cai, Ling; Zhou, Yinghui

    2015-10-01

    Based on the current models of phosphoric acid fuel cells (PAFCs) and thermoelectric generators (TGs), a new hybrid system is proposed, in which the effects of multi-irreversibilities resulting from the activation, concentration, and ohmic overpotentials in the PAFC, Joule heat and heat leak in the TG, finite-rate heat transfer between the TG and the heat reservoirs, and heat leak from the PAFC to the environment are taken into account. Expressions for the power output and efficiency of the PAFC, TG, and hybrid system are analytically derived and directly used to discuss the performance characteristics of the hybrid system. The optimal relationship between the electric currents in the PAFC and TG is obtained. The maximum power output is numerically calculated. It is found that the maximum power output density of the hybrid system will increase about 150 Wm-2, compared with that of a single PAFC. The problem how to optimally match the load resistances of two subsystems is discussed. Some significant results for practical hybrid systems are obtained.

  8. Some aromatic hydrazone derivatives as inhibitors for the corrosion of C-steel in phosphoric acid solution.

    PubMed

    Fouda, Abd El-Aziz S; Al-Sarawy, Ahmed A; Radwan, Mohamed S

    2006-01-01

    The effect of furfural benzoylhydrazone and its derivatives (I-VII) as corrosion inhibitors for C-steel in 1M phosphoric acid solution has been studied by weight-loss and galvanostatic polarization techniques. A significant decrease in the corrosion rate of C-steel was observed in the presence of the investigated inhibitors. This study revealed that, the inhibition efficiency increases with increasing the inhibitor concentration, and the addition of iodide ions enhances it to a considerable extent. The effect of temperature on the inhibition efficiency of these compounds was studied using weight-loss method. Activation energy (E(a)*) and other thermodynamic parameters for the corrosion process were calculated and discussed. The galvanostatic polarization data indicated that, the inhibitors were of mixed-type, but the cathode is more polarized than the anode. The adsorption of these compounds on C-steel surface has been found to obey Frumkin's adsorption isotherm. The mechanism of inhibition was discussed in the light of the chemical structure of the undertaken inhibitors.

  9. Valoniopsis pachynema Extract as a Green Inhibitor for Corrosion of Brass in 0.1 N Phosphoric Acid Solution

    NASA Astrophysics Data System (ADS)

    Selva Kumar, R.; Chandrasekaran, V.

    2016-04-01

    The effect of marine alga Valoniopsis pachynema extract on corrosion inhibition of brass in phosphoric acid was investigated by weight-loss method, potentiodynamic polarization, and electrochemical impedance spectroscopy studies. The inhibition efficiency is found to increase with increasing concentration of extract and decreases with rise in temperature. The activation energy, thermodynamic parameters (free energy, enthalpy, and entropy change) and kinetic parameters (rate constant and half-life) for inhibition process were calculated. These thermodynamic and kinetic parameters indicate a strong interaction between the inhibitor and the brass surface. The inhibition is assumed to occur via adsorption of inhibitor molecules on brass surface, which obeys Temkin adsorption isotherm. The adsorption of inhibitor on the brass surface is exothermic, physical, and spontaneous, and follows first-order kinetics. The polarization measurements showed that the inhibitor behaves as a mixed type inhibitor and the higher inhibition surface coverage on the brass was predicted. Inhibition efficiency values were found to show good trend with weight-loss method, potentiodynamic polarization, and electrochemical impedance spectroscopy studies. Surface study techniques (FT-IR and SEM) were carried out to ascertain the inhibitive nature of the algal extract on the brass surface.

  10. Rare earth phosphors and phosphor screens

    DOEpatents

    Buchanan, Robert A.; Maple, T. Grant; Sklensky, Alden F.

    1981-01-01

    This invention relates to rare earth phosphor screens for converting image carrying incident radiation to image carrying visible or near-visible radiation and to the rare earth phosphor materials utilized in such screens. The invention further relates to methods for converting image carrying charged particles to image carrying radiation principally in the blue and near-ultraviolet region of the spectrum and to stabilized rare earth phosphors characterized by having a continuous surface layer of the phosphors of the invention. More particularly, the phosphors of the invention are oxychlorides and oxybromides of yttrium, lanthanum and gadolinium activated with trivalent cerium and the conversion screens are of the type illustratively including x-ray conversion screens, image amplifier tube screens, neutron imaging screens, cathode ray tube screens, high energy gamma ray screens, scintillation detector screens and screens for real-time translation of image carrying high energy radiation to image carrying visible or near-visible radiation.

  11. Lead immobilization using phosphoric acid in a smelter-contaminated urban soil.

    PubMed

    Yang, J; Mosby, D E; Casteel, S W; Blanchar, R W

    2001-09-01

    Transformation of soil lead (Pb) to pyromorphite, a lead phosphate, may be a cost-effective remedial strategy for immobilizing soil Pb and reducing Pb bioavailability. Soil treatment using phosphoric acid (H3PO4) was assessed for its efficacy to reduce Pb solubility and bioaccessibility. Soil containing 4,360 mg of Pb kg(-1), collected from a smelter-contaminated site in Joplin, MO, was reacted with 1,250, 2,500, 5,000, and 10,000 mg of P kg(-1) as H3PO4. The reaction was followed by measurements of Pb bioaccessibility, solubility products, and microprobe analyses. Soluble Pb concentration in the soil decreased with increasing H3PO4 addition. Adding 10,000 mg of P kg(-1) reduced bioaccessible Pb by 60%. The logarithm of bioaccessible Pb decreased as a linear function of increasing H3PO4 addition with an R2 of 0.989. A higher soil/solution ratio was required to extract bioaccessible Pb after the treatment. Microprobe analyses showed that the Pb particles contained P and Cl after the reaction, and the spectra generated by the wavelength-dispersive spectrometer were similar to those of synthetic chloropyromorphite. Lead solubility in the P-treated soil was less than predicted for hydroxypyromorphite [Pbs(PO4)3-OH] and greater than predicted for chloropyromorphite [Pbs(PO4)3Cl]. The P treatment caused approximately 23% redistribution of soil Pb from the clay and silt size fractions to the sand fraction. Soil treatment with H3PO4 resulted in the formation of a compound similar to chloropyromorphite and reduced bioaccessibility of soil Pb, which may have a potential as an in situ technique for Pb-contaminated soil remediation.

  12. Highly efficient heat recovery system for phosphoric acid fuel cells used for cooling telecommunication equipment

    NASA Astrophysics Data System (ADS)

    Ishizawa, Maki; Okada, Shigeru; Yamashita, Takashi

    To protect the global environment by using energy more efficiently, NTT is developing a phosphoric acid fuel cell (PAFC) energy system for telecommunication cogeneration systems. Fuel cells are used to provide electrical power to telecommunication equipment and the heat energy is used by absorption refrigerators to cool the telecommunication rooms throughout the year. We have recently developed a highly efficient system for recovering heat and water from the exhaust gases of a 200-kW (rated power) fuel cell. It is composed of a shell-and-tube type heat exchanger to recover high-temperature heat and a direct-contact cooler to recover the water efficiently and simply. The reformer and cathode exhaust gases from the fuel cell are first supplied to the heat exchanger and then to the cooler. The high-temperature (85-60°C) heat can be recovered, and the total efficiency including the heat recovered from the fuel-cell stack coolant can be improved by supplying the recovered heat to the dual-heat-input absorption refrigerator. The water needed for operating the fuel cell is also recovered from the exhaust gases. We are currently applying this heat and water recovery system to the PC25C-type fuel cell. Maximum total efficiency including electrical power efficiency is estimated to be 78% at the rated power of 200 kW: composed of 17% heat recovery for the fuel-cell stack coolant, 21% from the exhaust gas by improving the heat exchanger, and 40% from electrical conversion. Next, we plan to evaluate the usefulness of this heat recovery system for cooling telecommunication equipment.

  13. Transient responses of phosphoric acid fuel cell power plant system. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Lu, Cheng-Yi

    1983-01-01

    An analytical and computerized study of the steady state and transient response of a phosphoric acid fuel cell (PAFC) system was completed. Parametric studies and sensitivity analyses of the PAFC system's operation were accomplished. Four non-linear dynamic models of the fuel cell stack, reformer, shift converters, and heat exchangers were developed based on nonhomogeneous non-linear partial differential equations, which include the material, component, energy balance, and electrochemical kinetic features. Due to a lack of experimental data for the dynamic response of the components only the steady state results were compared with data from other sources, indicating reasonably good agreement. A steady state simulation of the entire system was developed using, nonlinear ordinary differential equations. The finite difference method and trial-and-error procedures were used to obtain a solution. Using the model, a PAFC system, that was developed under NASA Grant, NCC3-17, was improved through the optimization of the heat exchanger network. Three types of cooling configurations for cell plates were evaluated to obtain the best current density and temperature distributions. The steady state solutions were used as the initial conditions in the dynamic model. The transient response of a simplified PAFC system, which included all of the major components, subjected to a load change was obtained. Due to the length of the computation time for the transient response calculations, analysis on a real-time computer was not possible. A simulation of the real-time calculations was developed on a batch type computer. The transient response characteristics are needed for the optimization of the design and control of the whole PAFC system. All of the models, procedures and simulations were programmed in Fortran and run on IBM 370 computers at Cleveland State University and the NASA Lewis Research Center.

  14. Recent progress in luminescence tuning of Ce(3+) and Eu(2+)-activated phosphors for pc-WLEDs.

    PubMed

    Li, Guogang; Tian, Ying; Zhao, Yun; Lin, Jun

    2015-12-01

    Nowadays, phosphor converted white light-emitting diodes (pc-WLEDs) have been widely used in solid-state lighting and display areas due to their superior lifetime, efficiency, and reliability as well as significant reduction in power consumption. Phosphors are indispensable components of pc-WLED devices, and their luminescence properties determine the quality of WLED lighting and displays. In order to further achieve high luminous efficacy, chromatic stability, and color-rending properties in pc-WLEDs, much effort has been focused on improving current pc-WLED phosphors and developing novel pc-WLED phosphors recently. This review article concerns commonly used rare earth ion (Eu(2+) and Ce(3+)) activated inorganic phosphors, highlighting the important effect of spectral tuning via local structural variations on improving the luminescence performance of phosphors. The main spectral tuning strategies are discussed in detail and summarized, including (1) doping level control; (2) cationic substitution; (3) anionic substitution; (4) cationic-anionic substitution; (5) the crystal-site engineering approach; (6) mixing of nanophases. PMID:26421319

  15. Luminescent properties of a novel Al10O3N8:Eu2+ phosphor by a mechanochemical activation route

    NASA Astrophysics Data System (ADS)

    Yin, Liang-Jun; Xie, Wen-Jie; Jian, Xian; Feng, Yan-Yu; Tang, Hui; Luan, Chun-Hong; Liang, Ying-Lin; Wang, Chao; Xu, Xin

    2015-04-01

    A novel Al10O3N8:Eu2+ phosphor was prepared successfully by a mechanochemical activation route. With the help of high-energy ball milling, the starting materials were mostly transformed into an amorphous phase, which significantly promotes the synthesis of Al10O3N8 phase at a relatively moderate reaction condition. Al10O3N8:Eu2+ phosphor showed a broad blue emission band under ultraviolet-light excitation and small thermal quenching. Additionally, it was found that Al10O3N8:Eu2+ phosphor showed a strong blue emission under 147 nm excitation and shorter decay time compared with BAM:Eu2+ phosphor, making it a potential phosphor used in plasma display panels. Si-N doping was performed to further increase the luminescence intensity of Al10O3N8:Eu2+ phosphor and the related mechanism was discussed. Prospectively, it was feasible to apply the synthesis approach to other hardly achieved materials.

  16. Impact of the substrate loading regime and phosphoric acid supplementation on performance of biogas reactors and microbial community dynamics during anaerobic digestion of chicken wastes.

    PubMed

    Belostotskiy, Dmitry E; Ziganshina, Elvira E; Siniagina, Maria; Boulygina, Eugenia A; Miluykov, Vasili A; Ziganshin, Ayrat M

    2015-10-01

    This study evaluates the effects of increasing organic loading rate (OLR) and decreasing hydraulic retention time (HRT) as well as phosphoric acid addition on mesophilic reactors' performance and biogas production from chicken wastes. Furthermore, microbial community composition in reactors was characterized by a 16S rRNA gene-based pyrosequencing analysis. Each step of increasing OLR impacted on the activity of microorganisms what caused a temporary decrease in biogas production. The addition of phosphoric acid resulted in the increased biogas production with values between 361 and 447 mL g(VS)(-1) from day 61 to day 74 compared to control reactor (309-350 mL g(VS)(-1)). With reactors' operation, Bacteroidetes phylotypes were noticeably replaced with Firmicutes representatives, and significant increase of Clostridium sp. was identified. Within Euryarchaeota, Methanosarcina sp. dominated in all analyzed samples, in which high ammonium levels were detected (3.4-4.9 NH4(+)-N g L(-1)). These results can help in better understanding the anaerobic digestion process of simultaneously ammonium/phosphate-rich substrates.

  17. Phosphoric acid-etching promotes bond strength and formation of acid-base resistant zone on enamel.

    PubMed

    Li, N; Nikaido, T; Alireza, S; Takagaki, T; Chen, J-H; Tagami, J

    2013-01-01

    This study examined the effect of phosphoric acid (PA) etching on the bond strength and acid-base resistant zone (ABRZ) formation of a two-step self-etching adhesive (SEA) system to enamel. An etch-and-rinse adhesive (EAR) system Single Bond (SB) and a two-step SEA system Clearfil SE Bond (SE) were used. Human teeth were randomly divided into four groups according to different adhesive treatments: 1) SB; 2) SE; 3) 35% PA etching→SE primer→SE adhesive (PA/SEp+a); (4) 35% PA etching→SE adhesive (PA/SEa). Microshear bond strength to enamel was measured and then statistically analyzed using one-way analysis of variance and the Tukey honestly significant difference test. The failure mode was recorded and analyzed by χ( 2 ) test. The etching pattern of the enamel surface was observed with scanning electron microscope (SEM). The bonded interface was exposed to a demineralizing solution (pH=4.5) for 4.5 hours and then 5% sodium hypochlorite with ultrasonication for 30 minutes. After argon-ion etching, the interfacial ultrastructure was observed using SEM. The microshear bond strength to enamel of the SE group was significantly lower (p<0.05) than that of the three PA-etched groups, although the latter three were not significantly different from one another. The ABRZ was detected in all the groups. In morphological observation, the ABRZ in the three PA-etched groups were obviously thicker compared with the SE group with an irregular wave-shaped edge.

  18. Phosphorus-31 nuclear magnetic resonance chemical shifts of phosphoric acid derivatives.

    PubMed

    Wittmann, Z; Kovács, Z

    1985-07-01

    (31)P nuclear magnetic resonance chemical shifts of alkyi and alkylaryl phosphates, condensed phosphates, phosphoric arids and their salts, are reported. These are listed by classes of compounds so that relationships between chemical shifts and the substituent groups on phosphorus atoms can be recognized. These relationships are useful for qualitative identification of the specific compounds listed and of related compounds by extrapolation.

  19. Protecting-Group-Free Total Synthesis of (-)-Lycopodine via Phosphoric Acid Promoted Alkyne Aza-Prins Cyclization.

    PubMed

    Ma, Donghui; Zhong, Zhuliang; Liu, Zaimin; Zhang, Mingjie; Xu, Shiyan; Xu, Dengyu; Song, Dengpeng; Xie, Xingang; She, Xuegong

    2016-09-01

    A protecting-group-free route for the total synthesis of (-)-lycopodine was demonstrated in only 8 steps from Wade's fawcettimine enone (12 steps from commercial availiable (R)-(+)-pulegone). The key core of this alkaloid was constructed through a phosphoric acid promoted and highly stereocontrolled alkyne aza-Prins cyclization reaction, synchronously establishing the bridged B-ring and the C13 quaternary stereocenter. Importantly, the synthesis further features a new efficient approach for the preparation of other lycopodine-type alkaloids. PMID:27529730

  20. Modeling of facilitated transport of phenylalanine by emulsion liquid membranes with di(2-ethylhexyl)phosphoric acid as a carrier

    SciTech Connect

    Liu, X.; Liu, D.

    1998-12-01

    A mathematical model is developed in this paper to simulate the facilitated transport of phenylalanine (Phe) in emulsion liquid membrane (ELM) systems with di(2-ethylhexyl)phosphoric acid as a carrier. The model takes into account the mass transfer in both the external aqueous phase and the organic membrane phase interfacial reaction as well as membrane breakage during agitation. The model is tested by comparing theoretical predications with experimental results using Phe extraction by ELM processes. It is found that the model is valid for simulating the facilitated transport of Phe with ELM under various experimental conditions.

  1. Luminescence properties of europium?terbium double activated calcium tungstate phosphor*1

    NASA Astrophysics Data System (ADS)

    Nazarov, M. V.; Jeon, D. Y.; Kang, J. H.; Popovici, E.-J.; Muresan, L.-E.; Zamoryanskaya, M. V.; Tsukerblat, B. S.

    2004-08-01

    Double incorporation of Eu 3+ and Tb 3+ ions into a CaWO 4 crystalline lattice modifies the luminescence spectrum due to the formation of new emission centers. Depending on the activators concentration and nature, as well as on the interaction between the activators themselves, the luminescence color can be varied within the entire range of the visible spectrum. Variable luminescence was obtained when CaWO 4:Eu,Tb phosphors with 0-5 mol% activator ions were exposed to relatively low excitation energies as UV (365 and 254 nm). Under high energy excitation such as VUV (147 nm) radiation or electron beam, white light has been observed. This material with controlled properties seems to be promising for the applications in fluorescent lamps, colored lightning for advertisement industries, and other optoelectronic devices.

  2. Advanced phosphors

    DOEpatents

    Xiang, Xiao-Dong; Sun, Xiaodong; Schultz, Peter G.

    2000-01-01

    This invention relates to new phosphor materials and to combinatorial methods of synthesizing and detecting the same. In addition, methods of using phosphors to generate luminescence are also disclosed.

  3. Fine-sized Tb3Al5O12:Ce phosphor powders prepared by spray pyrolysis from spray solution with ethylenediaminetetraacetic acid

    NASA Astrophysics Data System (ADS)

    Kim, Hyung Tae; Kim, Jung Hyun; Hong, Young Jun; Lee, Jung-Kul; Kang, Yun Chan

    2012-06-01

    Fine Tb2.91Al5O12:Ce0.09 (TAG:Ce) phosphor powders are prepared by spray pyrolysis from a spray solution with ethylenediaminetetraacetic acid (EDTA). EDTA is used as an organic additive to form hollow precursor powders as well as a chelating agent. The powders prepared from the spray solution with EDTA have mean sizes of 350, 400 and 604 nm at post-treatment temperatures of 1400°C, 1450°C and 1500°C, respectively. The phosphor powders prepared from the spray solution with EDTA have similar photoluminescence intensities at post-treatment temperatures of 1450°C and 1500°C. The photoluminescence intensity of the phosphor powders prepared from the spray solution with EDTA is 116% of that of the phosphor powders prepared from the spray solution without EDTA at a post-treatment temperature of 1450°C.

  4. Measurements of the effects of thermal contact resistance on steady state heat transfer in phosphoric-acid fuel cell stack

    NASA Technical Reports Server (NTRS)

    Abdul-Aziz, Ali; Alkasab, Kalil A.

    1991-01-01

    The influence of the thermal contact resistance on the heat transfer between the electrode plates, and the cooling system plate in a phosphoric-acid fuel-cell stack was experimentally investigated. The investigation was conducted using a set-up that simulates the operating conditions prevailing in a phosphoric acid fuel-cell stack. The fuel-cell cooling system utilized three types of coolants, water, engine oil, and air, to remove excess heat generated in the cell electrode and to maintain a reasonably uniform temperature distribution in the electrode plate. The thermal contact resistance was measured as a function of pressure at the interface between the electrode plate and the cooling system plate. The interface pressure range was from 0 kPa to 3448 kPa, while the Reynolds number for the cooling limits varied from 15 to 79 for oil, 1165 to 6165 for water, and 700 to 6864 for air. Results showed that increasing the interface pressure resulted in a higher heat transfer coefficient.

  5. Improved detection of multi-phosphorylated peptides in the presence of phosphoric acid in liquid chromatography/mass spectrometry

    SciTech Connect

    Kim, Jeongkwon; Camp, David G.; Smith, Richard D.

    2004-02-18

    In contrast to lower phosphorylation states (e.g., the tryptic monophosphopeptide FQpSEEQQQTEDELQDK from bovine -casein), the specific detection of multi-phosphorylated peptides (e.g. the tetraphosphopeptide RELEELNVPGEIVEpSLpSpSpSEESITR from tryptic digestion of bovine -casein) has often been problematic for liquid chromatography-mass spectrometry analysis due to their high affinity for adsorption to exposed surfaces. We observed an enhancement in the overall detection of phosphopeptides upon addition of phosphoric acid (0.1% to 1.0%) to the sample solution; a 10-fold increase in sensitivity was measured for the detection of two tryptic phosphopeptides as well as a significant improvement in the detection of the tetraphosphopeptide. Using capillary LC with an ion trap tandem mass spectrometer for detection and identification, the achievable detection limits were 50 fmol and 50 pmol for the monophosphopeptide and the tetraphosphopeptide, respectively. Phosphoric acid is believed to act as a blocking agent to available silanol groups on both the silica capillary surface and the C-18-bonded silica surface.

  6. Synthesis and characterization of diphenyl quinoline and bromine-activated diphenyl quinoline organic phosphors.

    PubMed

    Pimpalshende, D M; Dhoble, S J

    2014-08-01

    A diphenyl quinoline (DPQ)-conjugated derivative and bromine-activated DPQ (Br-DPQ) were synthesized in an inert gas atmosphere at 140 °C using Friedlander condensation. The compounds showed blue emission under a UV source. The structures were characterized by X-ray diffraction and Fourier transform infrared spectroscopy. The photoluminescence properties of the compounds were analysed using excitation and emission spectra. The synthesized organic phosphors shows bright emission in the blue region, with peaks at 445 and 453 nm, respectively, for DPQ and Br-DPQ in the powder form. The physical and photoluminescence properties of these organic compounds reveal promising blue emitters for high-efficiency organic light-emitting diodes.

  7. Analytical applications of condensed phosphoric acid-III Iodometric determination of sulphur after reduction of sulphate with sodium hypophosphite and either tin metal or potassium iodide in condensed phosphoric acid.

    PubMed

    Mizoguchi, T; Iwahori, H; Ishii, H

    1980-06-01

    Novel methods for the reduction of sulphate to hydrogen sulphide with hypophosphite-tin metal or hypophosphite-iodide in condensed phosphoric acid (CPA) are proposed. The reduction of sulphate with hypophosphite alone does not proceed quantitatively. Sulphate, however, is quantitatively decomposed with hypophosphite when tin metal or potassium iodide is used together with it. The determination of sulphur by the hypophosphite-tin metal-CPA and tin(II)-CPA methods is interfered with by copper on account of the stabilization of copper(I) sulphide, but this interference can be eliminated by adding iodide, e.g. potassium and lead salts. Alum and barytes are quantitatively decomposed within 15 min at 140 and 280 degrees , respectively. The hydrogen sulphide evolved is absorbed in zinc acetate solution at pH 4.5 and then determined by iodometry.

  8. Thermoluminescent phosphor

    DOEpatents

    Lasky, Jerome B.; Moran, Paul R.

    1978-01-01

    A thermoluminescent phosphor comprising LiF doped with boron and magnesium is produced by diffusion of boron into a conventional LiF phosphor doped with magnesium. Where the boron dopant is made to penetrate only the outer layer of the phosphor, it can be used to detect shallowly penetrating radiation such as tritium beta rays in the presence of a background of more penetrating radiation.

  9. Preparation, luminescence and defect studies of Eu{sup 2+}-activated strontium hexa-aluminate phosphor prepared via combustion method

    SciTech Connect

    Singh, Vijay; Gundu Rao, T.K.; Zhu Junjie . E-mail: jjzhu@nju.edu.cn

    2006-08-15

    Preparation of Eu{sup 2+} ions activated strontium hexa-aluminate phosphor using the combustion method is described. An efficient phosphor can be prepared by this method at reaction temperatures as low as 500 deg. C in a few minutes. Powder X-ray diffraction (XRD), transmission electron microscopy, scanning electron microscope analysis were used to characterize the as prepared product and the optical properties were studied by photoluminescence (PL) spectra. Thermally stimulated luminescence studies also have been carried out on SrAl{sub 12}O{sub 19}:Eu{sup 2+} phosphor. The TSL glow curve is broad and indicates two dominant peaks at 206 and 345 deg. C. Defect centres formed in irradiated phosphor have been studied using the technique of electron spin resonance. One of the centres is characterized by an isotropic g-value of 2.0055 and is assigned to a F{sup +} centre. The two annealing stages of F{sup +} centre in the region 125-230 and 340-390 deg. C appear to correlate with the release of carriers resulting in TSL peaks at 206 and 345 deg. C, respectively. - Graphical abstract: SEM image of SrAl{sub 12}O{sub 19}:Eu.

  10. Laser Fired Local Back Contact C-Si Solar Cells Using Phosphoric Acid for Back Surface Field

    NASA Astrophysics Data System (ADS)

    Balaji, Nagarajan; Park, Cheolmin; Ju, Minkyu; Lee, Seunghwan; Kim, Jungmo; Chung, Sungyoun; Raja, Jayapal; Yi, Junsin

    2015-04-01

    We report on a laser doping process for the formation of a local back surface field (BSF) using phosphoric acid (H3PO4) for n-type passivated emitter rear totally diffused silicon solar cells. The sheet resistance of the BSF layer was varied by changing the H3PO4 concentration. The BSF layer was passivated using SiN x . With the passivated BSF, the LBC solar cell shows an improved open circuit voltage. A laser power of 44 mW with 10 kHz resulted in a 45-Ω/sq BSF layer with effective lifetime of 290 μs and a higher V oc of 623 mV. With the optimized laser parameters, devices with the best electrical results yielded a short circuit current density of 36 mA/cm2 and an efficiency of 18.26%.

  11. Nitric-phosphoric acid etching effects on the surface chemical composition of CdTe thin film.

    NASA Astrophysics Data System (ADS)

    Irfan, Irfan; Ding, Huanjun; Xia, Wei; Lin, Hao; Tang, Ching W.; Gao, Yongli

    2009-03-01

    Nitric-phosphoric (NP) acid etching has been regarded as one of the most successful methods for the formation of low resistance back contact with the metal electrode in CdTe based solar cells. We report back surface chemical composition for eight different durations of NP etching of CdTe polycrystalline thin film. We studied the surfaces with x-ray photoemission spectroscopy (XPS), ultraviolet photoemission spectroscopy (UPS), inverse photoemission spectroscopy (IEPS) and atomic force microscopy (AFM). Etching dependence on the back surface composition and electronic structure was observed. Valence and conduction band shifts relative to the Fermi level of the system with different etching duration were analyzed. The sample was left in open ambient condition for three weeks and XPS data were obtained again in order to study the difference in surface chemical composition with the pristine CdTe film. Unetched and highly etched part of the sample were sputtered and the depth profile analyzed.

  12. Luminescence properties of compounds of europium(III) with quinaldic acid and phosphor-containing neutral ligands

    NASA Astrophysics Data System (ADS)

    Kalinovskaya, I. V.

    2016-06-01

    Luminescent complex mixed-ligand compounds of europium(III) with quinaldic acid and phosphor- containing neutral ligands have been obtained. Their composition and structure have been determined. The thermal and spectral-luminescent properties of the obtained complex mixed-ligand compounds of europium( III) have been studied. It is shown that, during thermolysis, a water molecule and neutral ligand are detached in two stages with endothermic effects. It is established that quinaldinate ion is coordinated to europium(III) ion in a bidentate fashion. The Stark structure of the 5 D 0-7 F j ( j = 0, 1, 2) transitions in low-temperature luminescence spectra of complex compounds of europium(III) has been analyzed.

  13. Morphology of the diastereomeric salt of the alkaloid ephedrine and a chlorine substituted cyclic phosphoric acid (CLINAM)

    NASA Astrophysics Data System (ADS)

    Strom, C. S.; Leusen, F. J. J.; Geertman, R. M.; Ariaans, G. J. A.

    1997-01-01

    The morphology of the diastereomeric salt of the alkaloid ephedrine and a chlorine substituted cyclic phosphoric acid is studied theoretically by means of a first-principles application of Hartman's PBC theory. A rigorous graph-theoretic derivation of the F slices of CLINAM and 2,4-DICLINAM has yielded all possible growth layers and their orientations. The Coulomb and Van der Waals contributions to the energy quantities characterizing CLINAM are calculated, using the Ewald formulation adjusted to lamina shapes, exactly and free from adjustable parameters. Several schemes of computing partial charges, in combination with energy minimization techniques are used for computing the atomic point charges. The structural morphology follows from the total attachment energies. The theoretical growth habit depends sensitively on the choice of the employed atomic charge scheme. The theoretical morphology of CLINAM crystals is discussed in the light of experimental results.

  14. Study of formation of deep trapping mechanism by UV, beta and gamma irradiated Eu(3+) activated SrY2O4 and Y4Al2O9 phosphors.

    PubMed

    Dubey, Vikas; Kaur, Jagjeet; Parganiha, Yogita; Suryanarayana, N S; Murthy, K V R

    2016-04-01

    This paper reports the thermoluminescence properties of Eu(3+) doped different host matrix phosphors (SrY2O4 and Y4Al2O9). The phosphor is prepared by high temperature solid state reaction method. The method is suitable for large scale production and fixed concentration of boric acid using as a flux. The prepared samples were characterized by X-ray diffraction technique and the crystallite size calculated by Scherer's formula. The prepared phosphor characterized by Scanning Electron Microscopic (SEM), Fourier Transform Infrared (FTIR), Energy Dispersive X-ray analysis (EDX), thermoluminescence (TL) and Transmission Electron Microscopic (TEM) techniques. The prepared phosphors for different concentration of Eu(3+) ions were examined by TL glow curve for UV, beta and gamma irradiation. The UV 254nm source used for UV irradiation, Sr(90) source was used for beta irradiation and Co(60) source used for gamma irradiation. SrY2O4:Eu(3+)and Y4Al2O9:Eu(3+) phosphors which shows both higher temperature peaks and lower temperature peaks for UV, beta and gamma irradiation. Here UV irradiated sample shows the formation of shallow trap (surface trapping) and the gamma irradiated sample shows the formation of deep trapping. The estimation of trap formation was evaluated by knowledge of trapping parameters. The trapping parameters such as activation energy, order of kinetics and frequency factor were calculated by peak shape method. Here most of the peak shows second order of kinetics. The effect of gamma, beta and UV exposure on TL studies was also examined and it shows linear response with dose which indicate that the samples may be useful for TL dosimetry. Formation of deep trapping mechanism by UV, beta and gamma irradiated Eu(3+) activated SrY2O4 and Y4Al2O9 phosphors is discussed in this paper. PMID:26748019

  15. In the Bottlebrush Garden: The Structural Aspects of Coordination Polymer Phases formed in Lanthanide Extraction with Alkyl Phosphoric Acids.

    PubMed

    Ellis, Ross J; Demars, Thomas; Liu, Guokui; Niklas, Jens; Poluektov, Oleg G; Shkrob, Ilya A

    2015-09-01

    Coordination polymers (CPs) of metal ions are central to a large variety of applications, such as catalysis and separations. These polymers frequently occur as amorphous solids that segregate from solution. The structural aspects of this segregation remain elusive due to the dearth of the spectroscopic techniques and computational approaches suitable for probing such systems. Therefore, there is a lacking of understanding of how the molecular building blocks give rise to the mesoscale architectures that characterize CP materials. In this study we revisit a CP phase formed in the extraction of trivalent lanthanide ions by diesters of the phosphoric acid, such as the bis(2-ethylhexyl)phosphoric acid (HDEHP). This is a well-known system with practical importance in strategic metals refining and nuclear fuel reprocessing. A CP phase, referred to as a "third phase", has been known to form in these systems for half a century, yet the structure of the amorphous solid is still a point of contention, illustrating the difficulties faced in characterizing such materials. In this study, we follow a deductive approach to solving the molecular structure of amorphous CP phases, using semiempirical calculations to set up an array of physically plausible models and then deploying a suite of experimental techniques, including optical, magnetic resonance, and X-ray spectroscopies, to consecutively eliminate all but one model. We demonstrate that the "third phase" consists of hexagonally packed linear chains in which the lanthanide ions are connected by three O-P-O bridges, with the modifying groups protruding outward, as in a bottlebrush. The tendency to yield linear polynuclear oligomers that is apparent in this system may also be present in other systems yielding the "third phase", demonstrating how molecular geometry directs polymeric assembly in hybrid materials. We show that the packing of bridging molecules is central to directing the structure of CP phases and that by

  16. Unique photoluminescence degradation/recovery phenomena in trivalent ion-activated phosphors

    SciTech Connect

    Sawada, Kenji; Adachi, Sadao

    2015-09-14

    Photo-induced luminescence intensity degradation in red-emitting Tb{sub 3}Ga{sub 5}O{sub 12}:Eu{sup 3+} (TGG:Eu{sup 3+}) phosphor is observed and studied using x-ray diffraction measurement, photoluminescence (PL) analysis, PL excitation spectroscopy, and PL decay analysis. The red-emitting TGG:Eu{sup 3+} phosphor exhibits remarkable degradation in the PL intensity under weak UV light (λ < 350 nm) exposure in the seconds time scale. The PL degradation characteristics can be well expressed by the exponential formulation with respect to exposure time. Interestingly, the PL intensity recovers after a few minutes when the phosphor is stored in a dark room or exposed to the long-wavelength (λ > 350 nm) light. The luminescence decay dynamics measured by excitation at λ{sub ex} = 355 and 266 nm suggest that the present degradation/recovery processes are caused by the electron traps formed in the TGG:Eu{sup 3+} phosphor. The Tb{sup 3+} emission in TGG shows the essentially same degradation characteristics as those observed in the TGG:Eu{sup 3+} phosphor. The present luminescence degradation/recovery phenomena of the trivalent ions (4f → 4f transitions) may universally occur in various oxide phosphors such as TGG (Tb{sup 3+} emission) and CaTiO{sub 3}:Eu{sup 3+}.

  17. Photoluminescence and cathodoluminescence properties of Eu{sup 3+} ions activated AMoO{sub 4} (A = Mg, Ca, Sr, Ba) phosphors

    SciTech Connect

    Du, Peng; Yu, Jae Su

    2015-10-15

    Highlights: • Under 393 nm excitation, strong red emission located at 615 nm was observed in all the samples. • The Eu{sup 3+}-activated CaMoO{sub 4} phosphor exhibited the strongest PL properties. • The CIE chromaticity coordinate of Eu{sup 3+}-activated CaMoO{sub 4} phosphor was (0.647,0.352). • The color purity of Eu{sup 3+}-activated CaMoO{sub 4} phosphor was 92.8%. • Strong CL properties were observed in the Eu{sup 3+}-activated CaMoO{sub 4} phosphor. - Abstract: Eu{sup 3+}-activated AMoO{sub 4} (A = Mg, Ca, Sr, Ba) phosphors were synthesized by a solid-state reaction method. Photoluminescence and cathodoluminescence (CL) spectra as well as X-ray diffraction patterns were measured to characterize the fabricated samples. Under 393 nm excitation, strong red emissions located at ∼615 nm corresponding to the {sup 5}D{sub 0} → {sup 7}F{sub 2} transition of Eu{sup 3+} ions were observed in all the samples. Compared with other Eu{sup 3+} ions activated AMoO{sub 4} (A = Mg, Sr, Ba) phosphors, Eu{sup 3+}-activated CaMoO{sub 4} phosphor exhibited the strongest red emission intensity with better Commission Internationale de L’Eclairage chromaticity coordinate and higher color purity. Furthermore, the CL results indicated that the Eu{sup 3+}-activated CaMoO{sub 4} phosphor had excellent luminescence properties.

  18. Nanoporous anodic aluminum oxide with a long-range order and tunable cell sizes by phosphoric acid anodization on pre-patterned substrates

    PubMed Central

    Surawathanawises, Krissada; Cheng, Xuanhong

    2014-01-01

    Nanoporous anodic aluminum oxide (AAO) has been explored for various applications due to its regular cell arrangement and relatively easy fabrication processes. However, conventional two-step anodization based on self-organization only allows the fabrication of a few discrete cell sizes and formation of small domains of hexagonally packed pores. Recent efforts to pre-pattern aluminum followed with anodization significantly improve the regularity and available pore geometries in AAO, while systematic study of the anodization condition, especially the impact of acid composition on pore formation guided by nanoindentation is still lacking. In this work, we pre-patterned aluminium thin films using ordered monolayers of silica beads and formed porous AAO in a single-step anodization in phosphoric acid. Controllable cell sizes ranging from 280 nm to 760 nm were obtained, matching the diameters of the silica nanobead molds used. This range of cell size is significantly greater than what has been reported for AAO formed in phosphoric acid in the literature. In addition, the relationships between the acid concentration, cell size, pore size, anodization voltage and film growth rate were studied quantitatively. The results are consistent with the theory of oxide formation through an electrochemical reaction. Not only does this study provide useful operational conditions of nanoindentation induced anodization in phosphoric acid, it also generates significant information for fundamental understanding of AAO formation. PMID:24535886

  19. Nanoporous anodic aluminum oxide with a long-range order and tunable cell sizes by phosphoric acid anodization on pre-patterned substrates.

    PubMed

    Surawathanawises, Krissada; Cheng, Xuanhong

    2014-01-20

    Nanoporous anodic aluminum oxide (AAO) has been explored for various applications due to its regular cell arrangement and relatively easy fabrication processes. However, conventional two-step anodization based on self-organization only allows the fabrication of a few discrete cell sizes and formation of small domains of hexagonally packed pores. Recent efforts to pre-pattern aluminum followed with anodization significantly improve the regularity and available pore geometries in AAO, while systematic study of the anodization condition, especially the impact of acid composition on pore formation guided by nanoindentation is still lacking. In this work, we pre-patterned aluminium thin films using ordered monolayers of silica beads and formed porous AAO in a single-step anodization in phosphoric acid. Controllable cell sizes ranging from 280 nm to 760 nm were obtained, matching the diameters of the silica nanobead molds used. This range of cell size is significantly greater than what has been reported for AAO formed in phosphoric acid in the literature. In addition, the relationships between the acid concentration, cell size, pore size, anodization voltage and film growth rate were studied quantitatively. The results are consistent with the theory of oxide formation through an electrochemical reaction. Not only does this study provide useful operational conditions of nanoindentation induced anodization in phosphoric acid, it also generates significant information for fundamental understanding of AAO formation.

  20. Europium-activated phosphors containing oxides of rare-earth and group-IIIB metals and method of making the same

    DOEpatents

    Comanzo, Holly Ann; Setlur, Anant Achyut; Srivastava, Alok Mani

    2006-04-04

    Europium-activated phosphors comprise oxides of at least a rare-earth metal selected from the group consisting of gadolinium, yttrium, lanthanum, and combinations thereof and at least a Group-IIIB metal selected from the group consisting of aluminum, gallium, indium, and combinations thereof. A method for making such phosphors comprises adding at least a halide of at least one of the selected Group-IIIB metals in a starting mixture. The method further comprises firing the starting mixture in an oxygen-containing atmosphere. The phosphors produced by such a method exhibit improved absorption in the UV wavelength range and improved quantum efficiency.

  1. Europium-activated phosphors containing oxides of rare-earth and group-IIIB metals and method of making the same

    DOEpatents

    Comanzo, Holly Ann; Setlur, Anant Achyut; Srivastava, Alok Mani; Manivannan, Venkatesan

    2004-07-13

    Europium-activated phosphors comprise oxides of at least a rare-earth metal selected from the group consisting of gadolinium, yttrium, lanthanum, and combinations thereof and at least a Group-IIIB metal selected from the group consisting of aluminum, gallium, indium, and combinations thereof. A method for making such phosphors comprises adding at least a halide of at least one of the selected Group-IIIB metals in a starting mixture. The method further comprises firing the starting mixture in an oxygen-containing atmosphere. The phosphors produced by such a method exhibit improved absorption in the UV wavelength range and improved quantum efficiency.

  2. Sunlight activated long-lasting luminescence from Ba5Si8O21: Eu(2+),Dy(3+) phosphor.

    PubMed

    Wang, Pengjiu; Xu, Xuhui; Zhou, Dacheng; Yu, Xue; Qiu, Jianbei

    2015-02-16

    Visible-light persistent phosphors are commonly used as self-sustained night vision and fluorescence labeling materials. From the inspiration of the structure of six-membered rings plane in Ba4(Si3O8)2, a similar structure of Ba5Si8O21 is expected that could exhibit more excellent phosphorescence property. In this Article, we report a novel visible long-lasting luminescence phosphor of Eu(2+)/Dy(3+) codoped Ba5Si8O21 for the first time. Ba5Si8O21:Eu(2+),Dy(3+) phosphor could be activated effectively by sunlight or even in severe weather conditions, which is mainly attributed to the broad excitation spectrum (200-455 nm) and highly responds to UV-A and violet-light in the solar spectrum. After activation, Ba5Si8O21:Eu(2+),Dy(3+) emits intense emission at 380-680 nm with persistent phosphorescence beyond 16 h. Moreover, it exhibits excellent and stable phosphorescence even in water, indicating that Ba5Si8O21:Eu(2+),Dy(3+) will be a all-weather material that can be effectively and repeatedly charged by natural daylight in all kinds of open-air environments. Furthermore, the quantum tunneling behavior was illustrated in the afterglow mechanism. PMID:25603544

  3. Sources, solubility, and acid processing of aerosol iron and phosphorous over the South China Sea: East Asian dust and pollution outflows vs. Southeast Asian biomass burning

    NASA Astrophysics Data System (ADS)

    Hsu, S.-C.; Gong, G.-C.; Shiah, F.-K.; Hung, C.-C.; Kao, S.-J.; Zhang, R.; Chen, W.-N.; Chen, C.-C.; Chou, C. C.-K.; Lin, Y.-C.; Lin, F.-J.; Lin, S.-H.

    2014-08-01

    Iron and phosphorous are essential to marine microorganisms in vast regions in oceans worldwide. Atmospheric inputs are important allochthonous sources of Fe and P. The variability in airborne Fe deposition is hypothesized to serve an important function in previous glacial-interglacial cycles, contributing to the variability in atmospheric CO2 and ultimately the climate. Understanding the mechanisms underlying the mobilization of airborne Fe and P from insoluble to soluble forms is critical to evaluate the biogeochemical effects of these elements. In this study, we present a robust power-law correlation between fractional Fe solubility and non-sea-salt-sulfate / Total-Fe (nss-sulfate / FeT) molar ratio independent of distinct sources of airborne Fe of natural and/or anthropogenic origins over the South China Sea. This area receives Asian dust and pollution outflows and Southeast Asian biomass burning. This correlation is also valid for nitrate and total acids, demonstrating the significance of acid processing in enhancing Fe mobilization. Such correlations are also found for P, yet source dependent. These relationships serve as straightforward parameters that can be directly incorporated into available atmosphere-ocean coupling models that facilitate the assessment of Fe and P fertilization effects. Although biomass burning activity may supply Fe to the bioavailable Fe pool, pyrogenic soils are possibly the main contributors, not the burned plants. This finding warrants a multidisciplinary investigation that integrates atmospheric observations with the resulting biogeochemistry in the South China Sea, which is influenced by atmospheric forcings and nutrient dynamics with monsoons.

  4. Optimizing available phosphorus in calcareous soils fertilized with diammonium phosphate and phosphoric acid using Freundlich adsorption isotherm.

    PubMed

    Naeem, Asif; Akhtar, Muhammad; Ahmad, Waqar

    2013-01-01

    In calcareous soils, phosphorus (P) retention and immobilization take place due to precipitation and adsorption. Since soil pH is considered a major soil variable affecting the P sorption, an acidic P fertilizer could result in low P adsorption compared to alkaline one. Therefore, P adsorption from DAP and phosphoric acid (PA) required to produce desired soil solution P concentration was estimated using Freundlich sorption isotherms. Two soils from Faisalabad and T. T. Singh districts were spiked with 0, 10, and 20 % CaCO3 for 15 days. Freundlich adsorption isotherms (P = aC(b/a)) were constructed, and theoretical doses of PA and DAP to develop a desired soil solution P level (i.e., 0.20 mg L(-1)) were calculated. It was observed that P adsorption in soil increased with CaCO3. Moreover, at all the levels of CaCO3, P adsorption from PA was lower compared to that from DAP in both the soils. Consequently, lesser quantity of PA was required to produce desired solution P, 0.2 mg L(-1), compared to DAP. However, extrapolating the developed relationship between soil CaCO3 contents and quantity of fertilizer to other similar textured soils needs confirmation. PMID:24307878

  5. Surface layer erosion of natural caries lesions with phosphoric and hydrochloric acid gels in preparation for resin infiltration.

    PubMed

    Meyer-Lueckel, H; Paris, S; Kielbassa, A M

    2007-01-01

    The infiltration of proximal enamel lesions with low-viscosity light curing resins could be a viable approach to stop lesion progression. However, penetration of sealant might be hampered by the comparatively highly mineralized surface layers of natural lesions. Therefore, the aim of this study was to compare the efficacy of three different etching gels in removing the surface layer in various etching times. Extracted human molars and premolars showing proximal white spot lesions were cut across the demineralized areas. Ninety-six lesions expected from visual examination to be confined to the outer enamel (C1) were selected. The cut surface and half of each lesion were varnished, thus serving as control. Subsequently, the lesions were etched with either phosphoric (37%) or hydrochloric (5 or 15%) acid gel for 30-120 s (n = 8/group). Specimens were examined using confocal microscopy and transversal microradiography. Surface layer reduction was significantly increased in lesions etched with 15% HCl gel for 90 and 120 s compared to those etched with H(3)PO(4) gel for 30-120 s (p < 0.05). No significant differences regarding the depths of erosion in the lesions compared to sound enamel could be observed (p > 0.05). An effective reduction in the surface layer of natural enamel caries can be achieved by etching with 15% hydrochloric acid gel for 90-120 s.

  6. Phosphor thermometry system

    DOEpatents

    Beshears, David L.; Sitter, Jr., David N.; Andrews, William H.; Simpson, Marc L.; Abston, Ruth A.; Cates, Michael R.; Allison, Steve W.

    2000-01-01

    An apparatus for measuring the temperature of a moving substrate includes an air gun with a powder inlet port in communication with the outlet port of a powder reservoir, an air inlet port in communication with a pressurized air source, and an outlet nozzle spaced from and directed toward the moving substrate. The air gun is activated by the air pulses to spray controlled amounts of the powdered phosphor onto the moving substrate, where the phosphor assumes the temperature of the moving substrate. A laser produces light pulses, and optics direct the light pulses onto the phosphor on the moving substrate, in response to which the phosphor emits a luminescence with a decay rate indicative of the temperature of the phosphor. A collection lens is disposed to focus the luminescence, and a photodetector detects the luminescence focused by the collection lens and produces an electrical signal that is characteristic of the brightness of the luminescence. A processor analyzes the electrical signal to determine the decay characteristic of the luminescence and to determine the temperature of the phosphor from the decay characteristic.

  7. Extraction and isolation of TPE from other elements on ion exchangers in aqueous and aqueous-organic solutions of phosphoric acid

    SciTech Connect

    Guseva, L.I.; Tikhomirova, G.S.; Stepushkina, V.V.

    1988-07-01

    The behavior of Am-Es and other actinides on anion and cation exchange resins in aqueous and aqueous-organic solutions of phosphoric acid has been studied in a wide range of concentration of various components of the solution. The sorptivity of transplutonium elements (TPE) on anion exchangers from dilute H/sub 3/PO/sub 4/ with a concentration less than or equal to 1 M in presence of organic solvents (alcohols, ketones, etc.) and on cation exchangers from concentrated H/sub 3/PO/sub 4/ has been found to be significant. The possibility of use of phosphoric acid solutions for isolation of TPE from Th, Pa, U, Np, Pu, and Zr and separation of TPE in different oxidation states in presence of a high-purity oxidant has been shown.

  8. Research and development of a phosphoric acid fuel cell/battery power source integrated in a test-bed bus. Final report

    SciTech Connect

    1996-05-30

    This project, the research and development of a phosphoric acid fuel cell/battery power source integrated into test-bed buses, began as a multi-phase U.S. Department of Energy (DOE) project in 1989. Phase I had a goal of developing two competing half-scale (25 kW) brassboard phosphoric acid fuel cell systems. An air-cooled and a liquid-cooled fuel cell system were developed and tested to verify the concept of using a fuel cell and a battery in a hybrid configuration wherein the fuel cell supplies the average power required for operating the vehicle and a battery supplies the `surge` or excess power required for acceleration and hill-climbing. Work done in Phase I determined that the liquid-cooled system offered higher efficiency.

  9. Effect of sodium sulfite, carboxylic monomer, and phosphoric acid etching on bonding of tri-n-butylborane initiated resin to human enamel.

    PubMed

    Nogawa, Hiroshi; Koizumi, Hiroyasu; Akazawa, Nobutaka; Hiraba, Haruto; Nakamura, Mitsuo; Matsumura, Hideo

    2015-03-01

    The purpose of the present study is evaluation of bonding durability of tri-n-butylborane (TBB) initiated resin without 4-methacryloyloxyethyl trimellitate anhydride (4-META) joined to human enamel. Ground human enamel was bonded with TBB resin under six surface conditions: 1) as ground, 2) primed with Teeth Primer, 3) sodium sulfite solution, 4) 4-META solution, 5) acetone-water, and 6) phosphoric acid etching. Pre- and post-thermocycling bond strengths and change in strength after thermocycling were compared. Etching enamel with 35-45% phosphoric acid enhanced bonding durability between enamel and TBB-initiated resin. Priming with Teeth Primer or 4-META solution improved bond strength between enamel and TBB-initiated resin. Sodium sulfite had little effect on enamel bonding in the present bonding systems. PMID:25807904

  10. Fuel ethanol production from corn stover under optimized dilute phosphoric acid pretreatment and enzymatic hydrolysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ethanol is a renewable oxygenated fuel. Dilute acid pretreatment is a promising pretreatment technology for conversion of lignocellulosic biomass to fuel ethanol. Generation of fermentable sugars from corn stover involves pretreatment and enzymatic saccharification. Pretreatment is crucial as nat...

  11. Determination of free silica in dust particles: effect of particle size for the X-ray diffraction and phosphoric acid methods.

    PubMed

    Yabuta, Juji; Ohta, Hisayosi

    2003-07-01

    The X-ray diffraction method and the phosphoric acid method are widely used to determine the fraction of free silica (mainly quartz and other silica polymorphs) in respirable dust sampled in working environments in Japan. In this study, we clarified the size effect of quartz dust for the X-ray diffraction method and the phosphoric acid method using size controlled quartz samples. The quartz samples were classified into 6 fractions with different size ranges: 1 microm and smaller, 1 to 3 microm, 3 to 5 microm, 5 to 7 microm, 7 to 10 microm and 10 microm and larger. Both of the determination methods were affected by the particle size, and especially particles smaller than 3 microm fairly dissolved in hot phosphoric acid and reduced X-ray diffraction intensity remarkably. If the content of these fine particles in the standard quartz sample is lower than that of the test samples, the fraction of free silica may be underestimated by these methods. For this reason, the standard quartz sample should have a representative size distribution of the field samples. The dust samples containing quartz were collected at a foundry and dissolved by phosphoric acid to remove non-quartz materials. The size fractions of dissolved samples were 50% for 5-10 microm, 25% for 3-5 microm, 20% for 1-3 microm and 5% for 1 microm and smaller. As the size distribution is similar to the present standard sample widely used in Japan, we concluded that the standard sample is suitable for these determination methods. PMID:12916756

  12. Influence of duration of phosphoric acid pre-etching on bond durability of universal adhesives and surface free-energy characteristics of enamel.

    PubMed

    Tsujimoto, Akimasa; Barkmeier, Wayne W; Takamizawa, Toshiki; Watanabe, Hidehiko; Johnson, William W; Latta, Mark A; Miyazaki, Masashi

    2016-08-01

    The purpose of this study was to evaluate the influence of duration of phosphoric acid pre-etching on the bond durability of universal adhesives and the surface free-energy characteristics of enamel. Three universal adhesives and extracted human molars were used. Two no-pre-etching groups were prepared: ground enamel; and enamel after ultrasonic cleaning with distilled water for 30 s to remove the smear layer. Four pre-etching groups were prepared: enamel pre-etched with phosphoric acid for 3, 5, 10, and 15 s. Shear bond strength (SBS) values of universal adhesive after no thermal cycling and after 30,000 or 60,000 thermal cycles, and surface free-energy values of enamel surfaces, calculated from contact angle measurements, were determined. The specimens that had been pre-etched showed significantly higher SBS and surface free-energy values than the specimens that had not been pre-etched, regardless of the aging condition and adhesive type. The SBS and surface free-energy values did not increase for pre-etching times of longer than 3 s. There were no significant differences in SBS values and surface free-energy characteristics between the specimens with and without a smear layer. The results of this study suggest that phosphoric acid pre-etching of enamel improves the bond durability of universal adhesives and the surface free-energy characteristics of enamel, but these bonding properties do not increase for phosphoric acid pre-etching times of longer than 3 s. PMID:27315775

  13. 40 CFR 721.6120 - Phosphoric acid, 1,2-eth-a-ne-diyl tet-ra-kis(2-chloro-1-meth-yl-ethyl) ester.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Phosphoric acid, 1,2-eth-a-ne-diyl tet-ra-kis(2-chloro-1-meth-yl-ethyl) ester. 721.6120 Section 721.6120 Protection of Environment...-diyl tet-ra-kis(2-chloro-1-meth-yl-ethyl) ester. (a) Chemical substances and significant new...

  14. 40 CFR 721.6120 - Phosphoric acid, 1,2-eth-a-ne-diyl tet-ra-kis(2-chloro-1-meth-yl-ethyl) ester.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Phosphoric acid, 1,2-eth-a-ne-diyl tet-ra-kis(2-chloro-1-meth-yl-ethyl) ester. 721.6120 Section 721.6120 Protection of Environment...-diyl tet-ra-kis(2-chloro-1-meth-yl-ethyl) ester. (a) Chemical substances and significant new...

  15. Influence of duration of phosphoric acid pre-etching on bond durability of universal adhesives and surface free-energy characteristics of enamel.

    PubMed

    Tsujimoto, Akimasa; Barkmeier, Wayne W; Takamizawa, Toshiki; Watanabe, Hidehiko; Johnson, William W; Latta, Mark A; Miyazaki, Masashi

    2016-08-01

    The purpose of this study was to evaluate the influence of duration of phosphoric acid pre-etching on the bond durability of universal adhesives and the surface free-energy characteristics of enamel. Three universal adhesives and extracted human molars were used. Two no-pre-etching groups were prepared: ground enamel; and enamel after ultrasonic cleaning with distilled water for 30 s to remove the smear layer. Four pre-etching groups were prepared: enamel pre-etched with phosphoric acid for 3, 5, 10, and 15 s. Shear bond strength (SBS) values of universal adhesive after no thermal cycling and after 30,000 or 60,000 thermal cycles, and surface free-energy values of enamel surfaces, calculated from contact angle measurements, were determined. The specimens that had been pre-etched showed significantly higher SBS and surface free-energy values than the specimens that had not been pre-etched, regardless of the aging condition and adhesive type. The SBS and surface free-energy values did not increase for pre-etching times of longer than 3 s. There were no significant differences in SBS values and surface free-energy characteristics between the specimens with and without a smear layer. The results of this study suggest that phosphoric acid pre-etching of enamel improves the bond durability of universal adhesives and the surface free-energy characteristics of enamel, but these bonding properties do not increase for phosphoric acid pre-etching times of longer than 3 s.

  16. Chiral phosphoric acid catalyzed highly enantioselective Friedel-Crafts alkylation reaction of C3-substituted indoles to β,γ-unsaturated α-ketimino esters.

    PubMed

    Bi, Bo; Lou, Qin-Xin; Ding, Yu-Yang; Chen, Sheng-Wei; Zhang, Sha-Sha; Hu, Wen-Hui; Zhao, Jun-Ling

    2015-02-01

    A highly enantioselective C2 Friedel-Crafts alkylation reaction of 3-substituted indoles to β,γ-unsaturated α-ketimino esters has been developed. This reaction was efficiently catalyzed by a chiral phosphoric acid catalyst. The corresponding C2-substituted indole derivatives, bearing an α-ketimino ester motif, were obtained in moderate to high yields (up to 93%) and with high enantioselectivities (up to >99% ee). PMID:25594307

  17. Growth, structural, spectral, mechanical, thermal and dielectric characterization of phosphoric acid admixtured L-alanine (PLA) single crystals

    NASA Astrophysics Data System (ADS)

    Rose, A. S. J. Lucia; Selvarajan, P.; Perumal, S.

    2011-10-01

    Phosphoric acid admixtured L-alanine (PLA) single crystals were grown successfully by solution method with slow evaporation technique at room temperature. Crystals of size 18 mm × 12 mm × 8 mm have been obtained in 28 days. The grown crystals were colorless and transparent. The solubility of the grown samples has been found out at various temperatures. The lattice parameters of the grown crystals were determined by X-ray diffraction technique. The reflection planes of the sample were confirmed by the powder X-ray diffraction study and diffraction peaks were indexed. Fourier transform infrared (FTIR) studies were used to confirm the presence of various functional groups in the crystals. UV-visible transmittance spectrum was recorded to study the optical transparency of grown crystal. The nonlinear optical (NLO) property of the grown crystal was confirmed by Kurtz-Perry powder technique and a study of its second harmonic generation efficiency in comparison with potassium dihydrogen phosphate (KDP) has been made. The mechanical strength of the crystal was estimated by Vickers hardness test. The grown crystals were subjected to thermo gravimetric and differential thermal analysis (TG/DTA). The dielectric behavior of the sample was also studied.

  18. Ultra-sensitive detection of zinc oxide nanowires using a quartz crystal microbalance and phosphoric acid DNA

    NASA Astrophysics Data System (ADS)

    Jang, Kuewhan; You, Juneseok; Park, Chanhoo; Park, Hyunjun; Choi, Jaeyeong; Choi, Chang-Hwan; Park, Jinsung; Lee, Howon; Na, Sungsoo

    2016-09-01

    Recent advancements of nanomaterials have inspired numerous scientific and industrial applications. Zinc oxide nanowires (ZnO NWs) is one of the most important nanomaterials due to their extraordinary properties. However, studies performed over the past decade have reported toxicity of ZnO NWs. Therefore, there has been increasing demand for effective detection of ZnO NWs. In this study, we propose a method for the detection of ZnO NW using a quartz crystal microbalance (QCM) and DNA probes. The detection method is based on the covalent interaction between ZnO NWs and the phosphoric acid group of single-stranded DNA (i.e., linker DNA), and DNA hybridization between the linker DNA and the probe DNA strand on the QCM electrode. Rapid, high sensitivity, in situ detection of ZnO NWs was demonstrated for the first time. The limit of detection was 10‑4 μg ml‑1 in deionized water, which represents a sensitivity that is 100000 times higher than the toxic ZnO NW concentration level. Moreover, the selectivity of the ZnO NW detection method was demonstrated by comparison with other types of nanowires and the method was able to detect ZnO NWs in tap water sensitively even after stored for 14 d in a refrigerator. The performance of our proposed method was sufficient to achieve detection of ZnO NW in the ‘real-world’ environment.

  19. Ultra-sensitive detection of zinc oxide nanowires using a quartz crystal microbalance and phosphoric acid DNA

    NASA Astrophysics Data System (ADS)

    Jang, Kuewhan; You, Juneseok; Park, Chanhoo; Park, Hyunjun; Choi, Jaeyeong; Choi, Chang-Hwan; Park, Jinsung; Lee, Howon; Na, Sungsoo

    2016-09-01

    Recent advancements of nanomaterials have inspired numerous scientific and industrial applications. Zinc oxide nanowires (ZnO NWs) is one of the most important nanomaterials due to their extraordinary properties. However, studies performed over the past decade have reported toxicity of ZnO NWs. Therefore, there has been increasing demand for effective detection of ZnO NWs. In this study, we propose a method for the detection of ZnO NW using a quartz crystal microbalance (QCM) and DNA probes. The detection method is based on the covalent interaction between ZnO NWs and the phosphoric acid group of single-stranded DNA (i.e., linker DNA), and DNA hybridization between the linker DNA and the probe DNA strand on the QCM electrode. Rapid, high sensitivity, in situ detection of ZnO NWs was demonstrated for the first time. The limit of detection was 10-4 μg ml-1 in deionized water, which represents a sensitivity that is 100000 times higher than the toxic ZnO NW concentration level. Moreover, the selectivity of the ZnO NW detection method was demonstrated by comparison with other types of nanowires and the method was able to detect ZnO NWs in tap water sensitively even after stored for 14 d in a refrigerator. The performance of our proposed method was sufficient to achieve detection of ZnO NW in the ‘real-world’ environment.

  20. Field assessment of treatment efficacy by three methods of phosphoric acid application in lead-contaminated urban soil.

    PubMed

    Yang, John; Mosby, David

    2006-07-31

    In situ soil treatment using phosphoric acid (H(3)PO(4)) may be an effective remedial technology for immobilizing soil Pb and reducing Pb risk to human health and ecosystem. The treatment efficacy of three H(3)PO(4) application methods was assessed in a smelter-contaminated urban soil located in the Jasper County Superfund Site, Missouri. Soil, with an average of 3529 mg Pb kg(-1) and in the 2- by 4-m plot size, was treated with H(3)PO(4) at a rate of 10 g P kg(-1) in four replicates by each of three methods: rototilling; surface application; pressure injection. Three soil cores, 2.5-cm diameter and 30-cm long, were taken from each plot before and 90 days after treatment and analyzed for soluble P, bioaccessible Pb and solid-Pb speciation. Applications of H(3)PO(4) induced the heterogeneity of soluble P in soil, with the highest concentrations in the surface. Three application methods mixed the H(3)PO(4) more effectively in the horizontals than the verticals of treated soil zone. The H(3)PO(4) applications significantly reduced Pb bioaccessibility in the soil, which was influenced by the concentrations of soil soluble P and solid-Pb species. The risk reductions of soil Pb were achieved by formation of pyromorphites or pyromorphite-like minerals. The rototilling appears to be the most effective treatment method in context of the homogeneity of soluble P and the reduction of Pb bioaccessibility in treated soil.

  1. Phase Structure Transition and Properties of Salt-Free Phosphoric Acid/Non-ionic Surfactants in Water.

    PubMed

    Wang, Lihuan; Zhao, Wenrong; Dong, Renhao; Hao, Jingcheng

    2016-08-23

    Precise control of phase structure transition for the synthesis of multi-dimensional soft materials is a fascinating target in amphiphilic molecule self-assembly. Here, we demonstrate a spontaneous formation of a closely packed lamellar phase consisting of uni- and multi-lamellar vesicles through the incorporation of a small amount of an extractant, di(2-ethylhexyl)phosphoric acid (DEHPA), into the highly swollen, planar lamellar phase of a non-ionic tetraethylene glycol monododecyl ether (C12EO4) surfactant in water. It is figured out that the introduction of negative membrane charges results in the electrostatic repulsion among the lamellae, which suppresses the Helfrich undulation and induces a phase structure transition from planar lamellae to closely packed vesicles. Our results provide important insight into amphiphilic molecule self-assembly, where additives and pH can satisfy the opportunities for the precise tuning of the lamellar structures, which makes a way for the development of lamellar soft materials. PMID:27490998

  2. Ultra-sensitive detection of zinc oxide nanowires using a quartz crystal microbalance and phosphoric acid DNA.

    PubMed

    Jang, Kuewhan; You, Juneseok; Park, Chanhoo; Park, Hyunjun; Choi, Jaeyeong; Choi, Chang-Hwan; Park, Jinsung; Lee, Howon; Na, Sungsoo

    2016-09-01

    Recent advancements of nanomaterials have inspired numerous scientific and industrial applications. Zinc oxide nanowires (ZnO NWs) is one of the most important nanomaterials due to their extraordinary properties. However, studies performed over the past decade have reported toxicity of ZnO NWs. Therefore, there has been increasing demand for effective detection of ZnO NWs. In this study, we propose a method for the detection of ZnO NW using a quartz crystal microbalance (QCM) and DNA probes. The detection method is based on the covalent interaction between ZnO NWs and the phosphoric acid group of single-stranded DNA (i.e., linker DNA), and DNA hybridization between the linker DNA and the probe DNA strand on the QCM electrode. Rapid, high sensitivity, in situ detection of ZnO NWs was demonstrated for the first time. The limit of detection was 10(-4) μg ml(-1) in deionized water, which represents a sensitivity that is 100000 times higher than the toxic ZnO NW concentration level. Moreover, the selectivity of the ZnO NW detection method was demonstrated by comparison with other types of nanowires and the method was able to detect ZnO NWs in tap water sensitively even after stored for 14 d in a refrigerator. The performance of our proposed method was sufficient to achieve detection of ZnO NW in the 'real-world' environment.

  3. Ultra-sensitive detection of zinc oxide nanowires using a quartz crystal microbalance and phosphoric acid DNA.

    PubMed

    Jang, Kuewhan; You, Juneseok; Park, Chanhoo; Park, Hyunjun; Choi, Jaeyeong; Choi, Chang-Hwan; Park, Jinsung; Lee, Howon; Na, Sungsoo

    2016-09-01

    Recent advancements of nanomaterials have inspired numerous scientific and industrial applications. Zinc oxide nanowires (ZnO NWs) is one of the most important nanomaterials due to their extraordinary properties. However, studies performed over the past decade have reported toxicity of ZnO NWs. Therefore, there has been increasing demand for effective detection of ZnO NWs. In this study, we propose a method for the detection of ZnO NW using a quartz crystal microbalance (QCM) and DNA probes. The detection method is based on the covalent interaction between ZnO NWs and the phosphoric acid group of single-stranded DNA (i.e., linker DNA), and DNA hybridization between the linker DNA and the probe DNA strand on the QCM electrode. Rapid, high sensitivity, in situ detection of ZnO NWs was demonstrated for the first time. The limit of detection was 10(-4) μg ml(-1) in deionized water, which represents a sensitivity that is 100000 times higher than the toxic ZnO NW concentration level. Moreover, the selectivity of the ZnO NW detection method was demonstrated by comparison with other types of nanowires and the method was able to detect ZnO NWs in tap water sensitively even after stored for 14 d in a refrigerator. The performance of our proposed method was sufficient to achieve detection of ZnO NW in the 'real-world' environment. PMID:27479871

  4. A fuel cell operating between room temperature and 250 °C based on a new phosphoric acid based composite electrolyte

    NASA Astrophysics Data System (ADS)

    Lan, Rong; Xu, Xiaoxiang; Tao, Shanwen; Irvine, John T. S.

    A phosphoric acid based composite material with core-shell microstructure has been developed to be used as a new electrolyte for fuel cells. A fuel cell based on this electrolyte can operate at room temperature indicating leaching of H 3PO 4 with liquid water is insignificant at room temperature. This will help to improve the thermal cyclability of phosphoric acid based electrolyte to make it easier for practical use. The conductivity of this H 3PO 4-based electrolyte is stable at 250 °C with addition of the hydrophilic inorganic compound BPO 4 forming a core-shell microstructure which makes it possible to run a PAFC at a temperature above 200 °C. The core-shell microstructure retains after the fuel cell measurements. A power density of 350 mW/cm 2 for a H 2/O 2 fuel cell has been achieved at 200 °C. The increase in operating temperature does not have significant benefit to the performance of a H 2/O 2 fuel cell. For the first time, a composite electrolyte material for phosphoric acid fuel cells which can operate in a wide range of temperature has been evaluated but certainly further investigation is required.

  5. High temperature dilute phosphoric acid pretreatment of corn stover for furfural and ethanol production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Furfural was produced from corn stover by one stage pretreatment process using dilute H3PO4 and solid residues following furfural production were used for ethanol production by Saccharomyces cerevisiae NRRL- Y2034. A series of experiments were conducted at varied temperatures (140-200 oC) and acid ...

  6. Green Phosphors

    NASA Astrophysics Data System (ADS)

    Singh, Vijay; Chakradhar, R. P. S.; Rao, J. L.; Dhoble, S. J.; Kim, S. H.

    2014-11-01

    Manganese-doped LaMgAl11O19 powder has been prepared by an easy combustion method. Powder x-ray diffraction and scanning electron microscopy have been used to characterize the as-prepared phosphor. The electron paramagnetic resonance (EPR) spectrum of LaMgAl11O19:Mn2+ phosphor exhibits six-line hyperfine structure centered at g ≈ 1.973. The number of spins participating in resonance ( N) and the paramagnetic susceptibility ( χ) for the resonance signal at g ≈ 1.973 have been calculated as a function of temperature. The photoluminescence spectrum exhibits green emission at 516 nm, which is attributed to 4T1 → 6A1 transition of Mn2+ ions. From EPR and luminescence studies, it is observed that Mn2+ ions occupy Mg2+ sites and Mn2+ ions are located at tetrahedral sites in the prepared phosphors.

  7. Preparation and Luminescence Properties of Eu2+-ACTIVATED Ba-Six-O-N Phosphors

    NASA Astrophysics Data System (ADS)

    Zhang, Ruili; Numata, Manaka; Maeda, Tomonori; Akazawa, Yuji; Murai, Kei-Ichiro; Moriga, Toshihiro

    A series of oxonitridosilicates phosphors Ba-Six-O-N /Eu2+ (x=Si/Ba=1~8, 5atom% Eu2+) were synthesized using traditional solid-state reaction. For x = 2~8, the main phase of the obtained samples was Ba3Si6O12N2. All Ba-Six-O-N /Eu2+ (x = 1~8) materials could be efficiently excited in the UV to visible region(310~450nm) and had a green emission at 508~522nm, making them attractive as conversion phosphors for white LED applications. With increasing x values, the emission peaks shifted to the longer wavelength region, while the emission intensity had a maximum at x = 6. The influence of the firing times was also discussed, after twice fired, there was a tendency of single-phased formed of the obtained materials and the emission intensity was greatly improved.

  8. Bonding to enamel/dentin etched with phosphoric and hydrofluoric acids.

    PubMed

    Barghi, Nassar; Covington, Kendra; Fischer, Dan E; Herbold, Edward T

    2004-10-01

    Repairing porcelain intraorally allows clinicians to provide their patients with a conservative means of treating fractured or debonded restorations. This requires, however, the etching of both porcelain and tooth structure with etching solutions. It is thus relevant to understand the effect that different etching procedures have on shear bond strengths of composite resins to both dentin and enamel structures. Based on the results of this investigation, the authors recommend isolation of tooth structures and the etching of porcelain with hydrofluoric acid.

  9. Modeling the hydrolysis of perfluorinated compounds containing carboxylic and phosphoric acid ester functions and sulfonamide groups.

    PubMed

    Rayne, Sierra; Forest, Kaya

    2010-01-01

    Temperature-dependent rate constants were estimated for the acid- and base-catalyzed and neutral hydrolysis reactions of perfluorinated telomer acrylates (FTAcrs) and phosphate esters (FTPEs), and the S(N)1 and S(N)2 hydrolysis reactions of fluorotelomer iodides (FTIs). Under some environmental conditions, hydrolysis of monomeric FTAcrs could be rapid (half-lives of several years in marine systems and as low as several days in some landfills) and represent a dominant portion of their overall degradation. Abiotic hydrolysis of monomeric FTAcrs may be a significant contributor to current environmental loadings of fluorotelomer alcohols (FTOHs) and perfluoroalkyl carboxylic acids (PFCAs). Polymeric FTAcrs are expected to be hydrolyzed more slowly, with estimated half-lives in soil and natural waters ranging between several centuries to several millenia absent additional surface area limitations on reactivity. Poor agreement was found between the limited experimental data on FTPE hydrolysis and computational estimates, requiring more detailed experimental data before any further modeling can occur on these compounds or their perfluoroalkyl sulfonamidoethanol phosphate ester (PFSamPE) analogs. FTIs are expected to have hydrolytic half-lives of about 130 days in most natural waters, suggesting they may be contributing to substantial FTOH and PFCA inputs in aquatic systems. Perfluoroalkyl sulfonamides (PFSams) appear unlikely to undergo abiotic hydrolysis at the S-N, C-S, or N-C linkages under environmentally relevant conditions, although potentially facile S-N hydrolysis via intramolecular catalysis by ethanol and acetic acid amide substituents warrants further investigation. PMID:20390888

  10. A new oxidimetric reagent: potassium dichromate in a strong phosphoric acid medium-VI Potentiometric titration of vanadium(III) alone and in mixture with vanadium(IV).

    PubMed

    Rao, G G; Rao, P K

    1966-09-01

    Vanadium(III) can be titrated at room temperature with potassium dichromate in an 8-12M phosphoric acid medium. Two potential breaks are observed in 12M phosphoric add with 0.2N potassium dichromate, the first corresponding to the oxidation of vanadium(III) to vanadium(IV) and the second to the oxidation of vanadium(IV) to vanadium(V). In titrations with 0.05N dichromate only the first break in potential is clearly observed. The method has been extended to the titration of mixtures of vanadium(III) and vanadium(IV). Conditions have also been found for the visual titration of vanadium(III) using ferroln or barium diphenylamine sulphonate as indicator.

  11. Phosphorous digestibility and activity of intestinal phytase in hybrid tilapia, Oreochromis niloticus X O. aureus

    USGS Publications Warehouse

    La Vorgna, M.W.; Hafez, Y.; Hughes, S.G.; Handwerker, T.

    2003-01-01

    Experiments were conducted to determine the degree to which phytate-bound phosphorus from plant protein sources could be used by hybrid tilapia (Oreochromis niloticus X O. aureus). Utilizing an inert marker technique with chromic oxide, hybrid tilapia in our study were effective at utilizing both inorganic and phytate phosphorus as evidenced by average apparent digestibility values of 93.2% and 90.0% for total and phytate phosphorus, respectively. Analysis of the intestinal brush border membrane of the tilapia revealed enzyme activity that was capable of hydrolyzing phytic acid. The presence of phytic acid hydrolyzing enzyme activity in the intestinal brush border provides a probable mechanism by which these hybrid tilapia are able to utilize phytate phosphorus effectively. ?? 2003 by The Haworth Press, Inc. All rights reserved.

  12. Importance of interatomic spacing in catalytic reduction of oxygen in phosphoric acid

    NASA Technical Reports Server (NTRS)

    Jalan, V.; Taylor, E. J.

    1983-01-01

    A correlation between the nearest-neighbor distance and the oxygen reduction activity of various platinum alloys is reported. It is proposed that the distance between nearest-neighbor Pt atoms on the surface of a supported catalyst is not ideal for dual site absorption of O2 or 'HO2' and that the introduction of foreign atoms which reduce the Pt nearest-neighbor spacing would result in higher oxygen reduction activity. This may allow the critical 0-0 bond interatomic distance and hence the optimum Pt-Pt separation for bond rupture to be determined from quantum chemical calculations. A composite analysis shows that the data on supported Pt alloys are consistent with Appleby's (1970) data on bulk metals with respect to specific activity, activation energy, preexponential factor, and percent d-band character.

  13. Cathode catalyst for primary phosphoric fuel cells

    NASA Technical Reports Server (NTRS)

    Walsh, F.

    1980-01-01

    Alkylation of Vulcan XC-72 provided the most stable bond type for linking CoTAA to the surface of the carbon; this result is based on data obtained by cyclic voltammetry, pulse voltammetry and by release of 14C from bonded CoTAA. Half-cell tests at 100 C in 85% phosphoric acid showed that CoTAA bonded to the surface of carbon (Vulcan XC-72) via an alkylation procedure is a more active catalyst than is platinum based on a factor of two improvement in Tafel slope; dimeric CoTAA has catalytic activity equal to platinum. Half-cell tests also showed that bonded CoTAA catalysts do not suffer a loss in potential when air is used as a fuel rather than oxygen. Commercially available PTFE was shown to be stable for four months in 200 C 85% phosphoric acid based on lack of change in surface wetting properties, IR and physical characteristics. When stressed electrochemically in 150 C 85% phosphoric acid, PTFE also showed no changes after one month.

  14. Highly proton conductive phosphoric acid-nonionic surfactant lyotropic liquid crystalline mesophases and application in graphene optical modulators.

    PubMed

    Tunkara, Ebrima; Albayrak, Cemal; Polat, Emre O; Kocabas, Coskun; Dag, Ömer

    2014-10-28

    Proton conducting gel electrolytes are very important components of clean energy devices. Phosphoric acid (PA, H(3)PO(4) · H2O) is one of the best proton conductors, but needs to be incorporated into some matrix for real device applications, such as into lyotropic liquid crystalline mesophases (LLCMs). Herein, we show that PA and nonionic surfactant (NS, C(12)H(25)(OCH(2)CH(2))(10)OH, C(12)E(10)) molecules self-assemble into PANS-LLCMs and display high proton conductivity. The content of the PANS-LLCM can be as high 75% H(3)PO(4) · H2O and 25% 10-lauryl ether (C(12)H(25)(OCH(2)CH(2))(10)OH, C(12)E(10)), and the mesophase follows the usual LLC trend, bicontinuous cubic (V1)-normal hexagonal (H1)-micelle cubic (I1), by increasing the PA concentration in the media. The PANS-LLCMs are stable under ambient conditions, as well as at high (up to 130 °C) and low (-100 °C) temperatures with a high proton conductivity, in the range of 10(-2) to 10(-6) S/cm. The mesophase becomes a mesostructured solid with decent proton conductivity below -100 °C. The mesophase can be used in many applications as a proton-conducting media as well as a phosphate source for the synthesis of various metal phosphates. As an application, we demonstrate a graphene-based optical modulator using supercapacitor structure formed by graphene electrodes and a PANS electrolyte. A PANS-LLC electrolyte-based supercapacitor enables efficient optical modulation of graphene electrodes over a range of wavelengths, from 500 nm to 2 μm, under ambient conditions.

  15. Effect of the application time of phosphoric acid and self-etch adhesive systems to sclerotic dentin

    PubMed Central

    MENA-SERRANO, Alexandra Patricia; GARCIA, Eugenio Jose; PEREZ, Miguel Muñoz; MARTINS, Gislaine Cristine; GRANDE, Rosa Helena Miranda; LOGUERCIO, Alessandro Dourado; REIS, Alessandra

    2013-01-01

    Objectives: To evaluate the effect of application time on the resin-dentin bond strength (µTBS) and etching pattern of adhesive systems applied on sclerotic dentine. Material and Methods: A total of forty-two bovine incisors had their roots removed. The 1-step self-etch GO (SDI), the 2-step self-etch Adper SE Bond (3MESPE) and the 35% phosphoric acid (3MESPE) from the 2-step etch-and-rinse Adper Single Bond 2 (3MESPE) were applied on the bovine incisal surfaces according to the manufacturer's instructions or duplicating the recommended conditioning time. After adhesive application, thirty teeth were restored with composite resin, stored for 24 h in distilled water at 37º C, and sectioned into resin-dentin bonded sticks (0.8 mm2) and tested according to the µTBS at 0.5 mm/min. The etching pattern of the remaining twelve teeth (n=4 for each material) was examined under scanning electron microscopy. Each tooth was divided into a buccal-to-lingual direction into three thirds, and each third randomly assigned to the groups: control (no treatment), according to the manufacturers' instructions and duplicating the recommended application time. The µTBS and the relative percentage of the tubule area opening were evaluated by two-way repeated measures ANOVA and Tukey's tests (α=0.05). Results: The duplication of the conditioning time favored only the GO adhesive (p<0.05). Both application methods significantly increased the tubule area opening (p<0.05) compared to the controls. Conclusions: The efficacy of duplicating the conditioning time was only effective for the 1-step self-etch adhesive system tested. PMID:23739856

  16. Effects of phosphoric acid sprayed into an incinerator furnace on the flue gas pressure drop at fabric filters.

    PubMed

    Takahashi, Shigetoshi; Hwang, In-Hee; Matsuto, Toshihiko

    2016-06-01

    Fabric filters are widely used to remove dust from flue gas generated by waste incineration. However, a pressure drop occurs at the filters, caused by growth of a dust layer on the filter fabric despite regular cleaning by pulsed-jet air. The pressure drop at the fabric filters leads to energy consumption at induced draft fan to keep the incinerator on negative pressure, so that its proper control is important to operate incineration facility efficiently. The pressure drop at fabric filters decreased whenever phosphoric acid wastewater (PAW) was sprayed into an incinerator for treating industrial waste. Operational data obtained from the incineration facility were analyzed to determine the short- and long-term effects of PAW spraying on the pressure drop. For the short-term effect, it was confirmed that the pressure drop at the fabric filters always decreased to 0.3-1.2kPa within about 5h after spraying PAW. This effect was expected to be obtained by about one third of present PAW spraying amount. However, from the long-term perspective, the pressure drop showed an increase in the periods of PAW spraying compared with periods for which PAW spraying was not performed. The pressure drop increase was particularly noticeable after the initial PAW spraying, regardless of the age and type of fabric filters used. These results suggest that present PAW spraying causes a temporary pressure drop reduction, leading to short-term energy consumption savings; however, it also causes an increase of the pressure drop over the long-term, degrading the overall operating conditions. Thus, appropriate PAW spraying conditions are needed to make effective use of PAW to reduce the pressure drop at fabric filters from a short- and long-term point of view.

  17. Environmental, health, and safety issues of fuel cells in transportation. Volume 1: Phosphoric acid fuel-cell buses

    SciTech Connect

    Ring, S

    1994-12-01

    The U.S. Department of Energy (DOE) chartered the Phosphoric Acid Fuel-Cell (PAFC) Bus Program to demonstrate the feasibility of fuel cells in heavy-duty transportation systems. As part of this program, PAFC- powered buses are being built to meet transit industry design and performance standards. Test-bed bus-1 (TBB-1) was designed in 1993 and integrated in March 1994. TBB-2 and TBB-3 are under construction and should be integrated in early 1995. In 1987 Phase I of the program began with the development and testing of two conceptual system designs- liquid- and air-cooled systems. The liquid-cooled PAFC system was chosen to continue, through a competitive award, into Phase H, beginning in 1991. Three hybrid buses, which combine fuel-cell and battery technologies, were designed during Phase III. After completing Phase II, DOE plans a comprehensive performance testing program (Phase HI) to verify that the buses meet stringent transit industry requirements. The Phase III study will evaluate the PAFC bus and compare it to a conventional diesel bus. This NREL study assesses the environmental, health, and safety (EH&S) issues that may affect the commercialization of the PAFC bus. Because safety is a critical factor for consumer acceptance of new transportation-based technologies the study focuses on these issues. The study examines health and safety together because they are integrally related. In addition, this report briefly discusses two environmental issues that are of concern to the Environmental Protection Agency (EPA). The first issue involves a surge battery used by the PAFC bus that contains hazardous constituents. The second issue concerns the regulated air emissions produced during operation of the PAFC bus.

  18. Effects of phosphoric acid sprayed into an incinerator furnace on the flue gas pressure drop at fabric filters.

    PubMed

    Takahashi, Shigetoshi; Hwang, In-Hee; Matsuto, Toshihiko

    2016-06-01

    Fabric filters are widely used to remove dust from flue gas generated by waste incineration. However, a pressure drop occurs at the filters, caused by growth of a dust layer on the filter fabric despite regular cleaning by pulsed-jet air. The pressure drop at the fabric filters leads to energy consumption at induced draft fan to keep the incinerator on negative pressure, so that its proper control is important to operate incineration facility efficiently. The pressure drop at fabric filters decreased whenever phosphoric acid wastewater (PAW) was sprayed into an incinerator for treating industrial waste. Operational data obtained from the incineration facility were analyzed to determine the short- and long-term effects of PAW spraying on the pressure drop. For the short-term effect, it was confirmed that the pressure drop at the fabric filters always decreased to 0.3-1.2kPa within about 5h after spraying PAW. This effect was expected to be obtained by about one third of present PAW spraying amount. However, from the long-term perspective, the pressure drop showed an increase in the periods of PAW spraying compared with periods for which PAW spraying was not performed. The pressure drop increase was particularly noticeable after the initial PAW spraying, regardless of the age and type of fabric filters used. These results suggest that present PAW spraying causes a temporary pressure drop reduction, leading to short-term energy consumption savings; however, it also causes an increase of the pressure drop over the long-term, degrading the overall operating conditions. Thus, appropriate PAW spraying conditions are needed to make effective use of PAW to reduce the pressure drop at fabric filters from a short- and long-term point of view. PMID:27040089

  19. Removal of arsenic and cadmium with sequential soil washing techniques using Na2EDTA, oxalic and phosphoric acid: Optimization conditions, removal effectiveness and ecological risks.

    PubMed

    Wei, Meng; Chen, Jiajun; Wang, Xingwei

    2016-08-01

    Testing of sequential soil washing in triplicate using typical chelating agent (Na2EDTA), organic acid (oxalic acid) and inorganic weak acid (phosphoric acid) was conducted to remediate soil contaminated by heavy metals close to a mining area. The aim of the testing was to improve removal efficiency and reduce mobility of heavy metals. The sequential extraction procedure and further speciation analysis of heavy metals demonstrated that the primary components of arsenic and cadmium in the soil were residual As (O-As) and exchangeable fraction, which accounted for 60% and 70% of total arsenic and cadmium, respectively. It was determined that soil washing agents and their washing order were critical to removal efficiencies of metal fractions, metal bioavailability and potential mobility due to different levels of dissolution of residual fractions and inter-transformation of metal fractions. The optimal soil washing option for arsenic and cadmium was identified as phosphoric-oxalic acid-Na2EDTA sequence (POE) based on the high removal efficiency (41.9% for arsenic and 89.6% for cadmium) and the minimal harmful effects of the mobility and bioavailability of the remaining heavy metals.

  20. Removal of arsenic and cadmium with sequential soil washing techniques using Na2EDTA, oxalic and phosphoric acid: Optimization conditions, removal effectiveness and ecological risks.

    PubMed

    Wei, Meng; Chen, Jiajun; Wang, Xingwei

    2016-08-01

    Testing of sequential soil washing in triplicate using typical chelating agent (Na2EDTA), organic acid (oxalic acid) and inorganic weak acid (phosphoric acid) was conducted to remediate soil contaminated by heavy metals close to a mining area. The aim of the testing was to improve removal efficiency and reduce mobility of heavy metals. The sequential extraction procedure and further speciation analysis of heavy metals demonstrated that the primary components of arsenic and cadmium in the soil were residual As (O-As) and exchangeable fraction, which accounted for 60% and 70% of total arsenic and cadmium, respectively. It was determined that soil washing agents and their washing order were critical to removal efficiencies of metal fractions, metal bioavailability and potential mobility due to different levels of dissolution of residual fractions and inter-transformation of metal fractions. The optimal soil washing option for arsenic and cadmium was identified as phosphoric-oxalic acid-Na2EDTA sequence (POE) based on the high removal efficiency (41.9% for arsenic and 89.6% for cadmium) and the minimal harmful effects of the mobility and bioavailability of the remaining heavy metals. PMID:27179243

  1. 1,2-Dichlorobenzene Pretreatment via Phosphoric Acid-Mediated Fenton Reagent.

    PubMed

    Richmond, Mark D

    2015-07-01

    A large industrial water resource recovery facility needed to significantly reduce the amount of 1,2-dichlorobenzene (ODCB) entering its biological treatment units. Numerous Advanced Oxidation Processes (AOPs) were considered based on literature and industry reports. Many AOPs appear to be incompatible with some of the native species present in groundwater or wastewater matrices. Iron, in particular, is often viewed as a nuisance increasing the complexity of the overall treatment scheme. The approach used in the current study was to incorporate the new AOP into the existing groundwater matrix and facilities as much as possible. To that end, native iron was exploited as the reaction catalyst, an acid was selected to fit with current macro nutrient needs of the biotreatment units, and the reactor was designed to require minimum modification of the existing facilities. The "green chemical" (Noyori, 2003) treatment process selected was demonstrated at full-scale, achieving good agreement with the results of prior laboratory studies. Up to eighty percent destruction of ODCB was demonstrated in a new pretreatment unit whose effluent fit seamlessly with the existing bioreactors. PMID:26163501

  2. Preparation and evaluation of advanced electrocatalysts for phosphoric acid fuel cells

    NASA Technical Reports Server (NTRS)

    Stonehart, P.; Baris, J.; Hochmuth, J.; Pagliaro, P.

    1981-01-01

    Two cooperative phenomena are required the development of highly efficient porous electrocatalysts: (1) is an increase in the electrocatalytic activity of the catalyst particle; and (2) is the availability of that electrocatalyst particle for the electromechanical reaction. The two processes interact with each other so that improvements in the electrochemical activity must be coupled with improvements in the availability of the electrocatalyst for reaction. Cost effective and highly reactive electrocatalysts were developed. The utilization of the electrocatalyst particles in the porous electrode structures was analyzed. It is shown that a large percentage of the electrocatalyst in anode structures is not utilized. This low utilization translates directly into a noble metal cost penalty for the fuel cell.

  3. Preparation and evaluation of advanced electrocatalysts for phosphoric acid fuel cells

    NASA Technical Reports Server (NTRS)

    Stonehart, P.; Baris, J.; Hochmuth, J.; Pagliaro, P.

    1981-01-01

    The highest performance fuel cell cathode electrocatalyst combination ever observed gives 755 mV vs hydrogen at 100 ASF on air at 180 C and shows a potential improvement to 775 mV vs hydrogen for better electrode structures. A pressurized fuel cell (UTC at 5 atm) would then give 805 mV at 320 ASF and 180 C. Another activity diagnostic is the performance of this electrocatalyst on oxygen at 900 mV vs hydrogen. The value for electrocatalyst is 44 mA per milligram of platinum and is projected to reach 60 mA per milligram of platinum with improved electrode structures. Since the electrocatalyst surface area and the electrode structure are not yet optimized there is considerable room for performance enhancement beyond these values, especially at higher temperatures.

  4. Luminescence Properties of Self-Activated Mm(VO4)2 (M = Mg, Ca, Sr, and Ba) Phosphors Synthesized by Solid-State Reaction Method.

    PubMed

    Min, Xin; Huang, Zhaohui; Fang, Minghao; Liu, Yan'gai; Tang, Chao; Wu, Xiaowen

    2016-04-01

    In this paper, M3(VO4)2 (M = Mg, Ca, Sr, and Ba) self-activated phosphors were prepared by a solid-state reaction method at 1,000 °C for 5 h. The phase formation and micrographs were analyzed by X-ray diffraction and scanning electron microscopy. The Ca3(VO4)2 phosphor does not show any emission peaks under excitation with ultraviolet (UV) light. However, the M3(VO4)2 (M = Mg, Sr, and Ba) samples are effectively excited by UV light chips ranging from 200 nm to 400 nm and exhibit broad emission bands due to the charge transfer from the oxygen 2p orbital to the vacant 3d orbital of the vanadium in the VO4. The color of these phosphors changes from yellow to light blue via blue-green with increasing ionic radius from Mg to Sr to Ba. The luminescence lifetimes and quantum yield decrease with the increasing unit cell volume and V-V distance, in the order of Mg3(VO4)2 to Sr3(VO4)2 to Ba3(VO4)2. The emission intensity decreases with the increase of temperatures, but presents no color shift. This confirms that these self-activated M3(VO4)2 phosphors can be suggested as candidates of the single-phase phosphors for light using UV light emitting diodes (LEDs). PMID:27451689

  5. Characterization of Hybrid Polyhedral Oligomeric Silsesquioxane (POSS)-Polybenzimidazole (PBI)-Phosphoric Acid (PA) Materials Intended for Proton Exchange Membranes (PEM)

    NASA Astrophysics Data System (ADS)

    Bubeck, Robert; Stark, Edmund; Decker, Berryinne; Hartmann-Thompson, Claire

    2013-03-01

    Isophthalic acid and 3,3'-diaminobenzidine (DAB) were polymerized in the presence of polyphosphoric acid (PPA) and various additives, degree of polymerization was monitored by viscosity and torque change measurements, and membranes were prepared by casting the reaction solution and allowing PPA to hydrolyze to PA under ambient conditions. As a function of relative humidity, the membranes were characterized for (1) acid content, (2) in-plane conductivity and (3) complex shear modulus G* obtained via oscillatory parallel plate dynamic mechanical spectroscopy. The addition of sulfonated octaphenyl polyhedral oligomeric silsesquixane (S-POSS) to m-polybenzimidazole (PBI)-phosphoric acid (PA) membranes resulted in increased in-plane proton conductivity at high temperatures (120-150 °C) and increased G* relative to a m-PBI control membrane and to m-PBI control membranes carrying comparable weight loadings of non-proton conducting octaphenyl-POSS nanoadditive or silica.

  6. Changes in mobility of toxic elements during the production of phosphoric acid in the fertilizer industry of Huelva (SW Spain) and environmental impact of phosphogypsum wastes.

    PubMed

    Pérez-López, Rafael; Alvarez-Valero, Antonio M; Nieto, José Miguel

    2007-09-30

    Presently, about 3 million tonnes of phosphogypsum are being generated annually in Spain as by-product from phosphoric acid in a fertilizer factory located in Huelva (southwestern Iberian Peninsula). Phosphate rock from Morocco is used as raw material in this process. Phosphogypsum wastes are stored in a stack containing 100Mt (approximately 1200ha of surface) over salt marshes of an estuary formed by the confluence of the Tinto and Odiel rivers, less than 1km away from the city centre. A very low proportion of this waste is used to improve fertility of agricultural soils in the area of the Guadalquivir river valley (Seville, SW Spain). The chemical speciation of potentially toxic elements (Ba, Cd, Cu, Ni, Sr, U and Zn) in phosphogypsum and phosphate rock was performed using the modified BCR-sequential extraction procedure, as described by the European Community Bureau of Reference (1999). This study has been done with the main of: (1) evaluate changes in the mobility of metals during the production of phosphoric acid; (2) estimate the amount of mobile metals that can affect the environmental surrounding; and (3) verify the environmentally safe use of phosphogypsum as an amendment to agricultural soils. The main environmental concern associated to phosphoric acid production is that Uranium, a radiotoxic element, is transferred from the non-mobile fraction in the phosphate rock to the bioavailable fraction in phosphogypsum in a rate of 23%. Around 21% of Ba, 6% of Cu and Sr, 5% of Cd and Ni, and 2% of Zn are also contained in the water-soluble phase of the final waste. Considering the total mass of phosphogypsum, the amount of metals easily soluble in water is approximately 6178, 3089, 1931, 579, 232, 193 and 77t for Sr, U, Ba, Zn, Ni, Cu and Cd, respectively. This gives an idea of the pollution potential of this waste. PMID:17683858

  7. Quantum-splitting oxide-based phosphors and method of producing the same

    DOEpatents

    Setlur, Anant Achyut; Srivastava, Alok Mani

    2003-09-02

    Strontium, calcium, strontium calcium, strontium calcium magnesium, calcium magnesium aluminates, and strontium borates activated with Pr.sup.3+ exhibit characteristics of quantum-splitting phosphors under VUV excitation. A large emission peak at about 405 nm under VUV excitation is used conveniently to identify quantum-splitting phosphors. Improvements may be achieved with addition of fluorides or boric acid as a flux during the preparation of the phosphors. It is also possible to predict improvement in quantum efficiency by observing the ratio of emission intensities at about 480 nm and about 610 nm.

  8. Mechanistic investigation of the influence of phosphoric and boric acids in the formation of homogeneous Ni-P/ZnO@SiO2 coatings.

    PubMed

    Sharifalhoseini, Zahra; Entezari, Mohammad H; Shahidi, Mohsen

    2016-02-15

    High agglomeration of the nanoparticles and low volume fraction of nanosized inert particles within the nanocomposite thin films are found as the practical problems. In our previous work, silica coated ZnO nanoparticles (ZnO@SiO2 NPs) were synthesized to prevent dissolution of the ZnO nanoparticles (ZnO NPs) in the electrolytic Ni bath. The high agglomeration of these core-shell particles led to an unequal particle distribution in the deposit matrix. In this work, we aimed to prepare a highly homogeneous nanocomposite coating by stabilizing the nanoparticles in the medium. Adding the buffering agents, including phosphoric and boric acids to the medium, disclosed their new aspect of these inorganic acids in the prevention of particle agglomeration. The corrosion study of the resulting well-dispersed Ni-P/Zn@SiO2 nanocomposite coating confirmed a significant increase in anticorrosion performance. This increase was about 2.3 times compared to the previously prepared coating. Moreover, the probable mechanisms of phosphoric and boric acids in particle stability through the steric or/and electrostatic repulsion at the interfaces between the colloidal nanoparticles (ZnO@SiO2 NPs) and the electrolyte solution were investigated in detail. PMID:26658358

  9. Mechanistic investigation of the influence of phosphoric and boric acids in the formation of homogeneous Ni-P/ZnO@SiO2 coatings.

    PubMed

    Sharifalhoseini, Zahra; Entezari, Mohammad H; Shahidi, Mohsen

    2016-02-15

    High agglomeration of the nanoparticles and low volume fraction of nanosized inert particles within the nanocomposite thin films are found as the practical problems. In our previous work, silica coated ZnO nanoparticles (ZnO@SiO2 NPs) were synthesized to prevent dissolution of the ZnO nanoparticles (ZnO NPs) in the electrolytic Ni bath. The high agglomeration of these core-shell particles led to an unequal particle distribution in the deposit matrix. In this work, we aimed to prepare a highly homogeneous nanocomposite coating by stabilizing the nanoparticles in the medium. Adding the buffering agents, including phosphoric and boric acids to the medium, disclosed their new aspect of these inorganic acids in the prevention of particle agglomeration. The corrosion study of the resulting well-dispersed Ni-P/Zn@SiO2 nanocomposite coating confirmed a significant increase in anticorrosion performance. This increase was about 2.3 times compared to the previously prepared coating. Moreover, the probable mechanisms of phosphoric and boric acids in particle stability through the steric or/and electrostatic repulsion at the interfaces between the colloidal nanoparticles (ZnO@SiO2 NPs) and the electrolyte solution were investigated in detail.

  10. Determination of Water Vapor Pressure Over Corrosive Chemicals Versus Temperature Using Raman Spectroscopy as Exemplified with 85.5% Phosphoric Acid.

    PubMed

    Rodier, Marion; Li, Qingfeng; Berg, Rolf Willestofte; Bjerrum, Niels Janniksen

    2016-07-01

    A method to determine the water vapor pressure over a corrosive substance was developed and tested with 85.5 ± 0.4% phosphoric acid. The water vapor pressure was obtained at a range of temperatures from ∼25 ℃ to ∼200 ℃ using Raman spectrometry. The acid was placed in an ampoule and sealed with a reference gas (either hydrogen or methane) at a known pressure (typically ∼0.5 bar). By comparing the Raman signals from the water vapor and the references, the water pressure was determined as a function of temperature. A considerable amount of data on the vapor pressure of phosphoric acid are available in the literature, to which our results could successfully be compared. A record value of the vapor pressure, 3.40 bar, was determined at 210 ℃. The method required a determination of the precise Raman scattering ratios between the substance, water, and the used reference gas, hydrogen or methane. In our case the scattering ratios between water and reference ν1 Q-branches were found to be 1.20 ± 0.03 and 0.40 ± 0.02 for H2 and CH4, respectively.

  11. Determination of Water Vapor Pressure Over Corrosive Chemicals Versus Temperature Using Raman Spectroscopy as Exemplified with 85.5% Phosphoric Acid.

    PubMed

    Rodier, Marion; Li, Qingfeng; Berg, Rolf Willestofte; Bjerrum, Niels Janniksen

    2016-07-01

    A method to determine the water vapor pressure over a corrosive substance was developed and tested with 85.5 ± 0.4% phosphoric acid. The water vapor pressure was obtained at a range of temperatures from ∼25 ℃ to ∼200 ℃ using Raman spectrometry. The acid was placed in an ampoule and sealed with a reference gas (either hydrogen or methane) at a known pressure (typically ∼0.5 bar). By comparing the Raman signals from the water vapor and the references, the water pressure was determined as a function of temperature. A considerable amount of data on the vapor pressure of phosphoric acid are available in the literature, to which our results could successfully be compared. A record value of the vapor pressure, 3.40 bar, was determined at 210 ℃. The method required a determination of the precise Raman scattering ratios between the substance, water, and the used reference gas, hydrogen or methane. In our case the scattering ratios between water and reference ν1 Q-branches were found to be 1.20 ± 0.03 and 0.40 ± 0.02 for H2 and CH4, respectively. PMID:27273974

  12. Fluroide concentration in enamel treated with 50% phosphoric acid and NaF with subsequent decalcification in "acid-gel".

    PubMed

    Bohrer, J; Gedalia, I

    1980-06-01

    Fluoride concentration of enamel surfaces treated with 50% H3PO4, together with high NaF contents or etched with 50% H3PO4 followed by application with a water solution of high NaF content, was examined. In addition, the degree of decalcification and the fluoride content of subsequently incubated enamel samples in acid-gel at 37 degrees C were determined. Generally, incubation highly increased the fluoride contents of the etched and fluoridated (experimental), control (etched only), and untreated (vaseline) enamel samples. An increasing demineralization effect was observed in the samples of the following order: experimental, control, and baseline. It appears does not predispose to an increased caries challenge in vitro.

  13. Oxidations of organic matter present in the phosphoric acid 54% by the ozone: characterization of groups carbonyls upstream and downstream of the ozonation

    NASA Astrophysics Data System (ADS)

    Linda, D.; Louati, A.; Chtara, C.; Kabadou, A.

    2012-02-01

    This study was focused on the oxidation of organic matter in phosphoric acid 54% by ozone. In order to understand the mechanisms involved in this process, the identification of this matter upstream and downstream of the ozonation was necessary. For the identification, after an extraction by a mixture (dichloro-methanol), the organic phase was divided into two parts: the residue and the extract:-The residue was studied by infrared spectroscopy Fourier Transform (IR-TF). It contains Kérogène which is a mixture of saturated hydrocarbons with high molecular weights. The absorption bands of the FT-IR showed that the residue contains also quantities of amino that correspond to the remains of dinoflagellate cysts, which are abundant in sediments.-The extract has been the subject of a detailed study by, chromatography on silica column, IR-TF spectroscopy and CG-SM. The passage of this extract on a silica column yielded two fractions (saturated fraction and polar fraction). Both of these fractions were analyzed by CG-SM. The yield of the reduction of the organic matter content in the phosphoric acid 54% could not exceed 29%. Therefore, we can conclude that the reduction in the rate of organic matter remains limited by the fact that some compounds are inert towards ozone.

  14. Effect of cavity preparation method on microtensile bond strength of a self-etching primer vs phosphoric acid etchant to enamel.

    PubMed

    de Souza-Zaroni, Wanessa Christine; Delfino, Carina Sinclér; Ciccone-Nogueira, Juliane Cristina; Palma-Dibb, Regina Guenka; Corona, Silmara Aparecida Milori

    2007-10-01

    This study evaluated the effect of cavity preparation using air abrasion or carbide bur on bond strength to enamel treated with a self-etching primer (Tyrian SPE) or a phosphoric acid etchant. Twenty-four molars were divided into three groups: high-speed; standard handpiece (ST air abrasion) or supersonic handpiece (SP air abrasion) of the same air-abrasive system. The enamel surfaces were treated with one of the two etchants and the same adhesive agent One Step Plus, and then composite buildups were done with Filtek Z250. After 24 h at 37 degrees C, beams (0.8 mm2) were obtained and subjected to tensile stress in a universal testing machine (0.5 mm/min). The data were submitted to analysis of variance and Tukey's test (P < 0.05). For the conditioning agents, it was observed that the specimens conditioned with phosphoric acid presented superior results than the specimens that used Tyrian SPE. For the preparation techniques, it was verified that the SP air abrasion groups showed the highest bond strengths and carbide-bur groups presented the lowest bond strengths when the specimens were conditioned with Tyrian SPE. It can be concluded that the influence of the cavity preparation method was dependent on the conditioning system used, only when using carbide-bur preparation technique.

  15. Photoluminescence properties of Eu(3+)/ Sm(3+) activated CaZr4(PO4)6 phosphors.

    PubMed

    Nair, Govind B; Dhoble, S J

    2016-09-01

    Solid state reaction method was employed for the synthesis of a series of CaZr4(PO4)6: Eu(3+)/Sm(3+) phosphors. The red-emitting CaZr4(PO4)6:Eu(3+) phosphors can be efficiently excited at 396 nm and thereby, exhibit a strong red luminescence predominantly corresponding to the electric dipole transition at 615 nm. Under 405 nm excitation, CaZr4(PO4)6:Sm(3+) phosphors display orange emission with color temperatures approximately around 2200 K. The acquired results reveal that CaZr4(PO4)6: RE(3+) (RE = Eu, Sm) phosphors could be potential candidates for red and orange emitting phosphor, respectively, for UV/blue-pump LEDs. PMID:27411525

  16. Photoluminescence properties of Eu(3+)/ Sm(3+) activated CaZr4(PO4)6 phosphors.

    PubMed

    Nair, Govind B; Dhoble, S J

    2016-09-01

    Solid state reaction method was employed for the synthesis of a series of CaZr4(PO4)6: Eu(3+)/Sm(3+) phosphors. The red-emitting CaZr4(PO4)6:Eu(3+) phosphors can be efficiently excited at 396 nm and thereby, exhibit a strong red luminescence predominantly corresponding to the electric dipole transition at 615 nm. Under 405 nm excitation, CaZr4(PO4)6:Sm(3+) phosphors display orange emission with color temperatures approximately around 2200 K. The acquired results reveal that CaZr4(PO4)6: RE(3+) (RE = Eu, Sm) phosphors could be potential candidates for red and orange emitting phosphor, respectively, for UV/blue-pump LEDs.

  17. Solvent effect on proton transfer in the complexes of N,N-dimethylformamide with sulfuric and phosphoric acid: A DFT investigation

    NASA Astrophysics Data System (ADS)

    Fedorova, Irina V.; Krestyaninov, Michael A.; Kiselev, Michael G.; Safonova, Lyubov P.

    2016-02-01

    Ab initio quantum-chemical calculations of structure and energies of the complexes of N,N-dimethylformamide (DMF) with sulfuric (H2SO4) and phosphoric (H3PO4) acids have been carried out. It has been found that the hydrogen bond between H2SO4 and DMF molecules is a little shorter and stronger than that between H3PO4 and DMF. The H-bond strength is different both in acid-acid and (acid)n-DMF complexes for n = 1, 2. The polar solvent effect is taken into account by using the CPCM approach. The differences of geometric parameters of the H-bonds in the gas phase and DMF are analyzed. The potential energy surface (PES) of the proton transfer reaction in acid-DMF and (acid)2-DMF complexes was calculated. The calculations have shown that the gas phase PES has a single distinct minimum (with the exception of the (H2SO4)2-DMF). In DMF, the proton transfer reaction takes place in all complexes, if OACID … ODMF distance is constrained. The solvent effect favors a proton transfer from sulfuric acid to oxygen atom of DMF molecule and formation of stable ionic pairs.

  18. Comparison analysis on the properties of the phosphor film according to the various composition ratio of phosphor slurry

    NASA Astrophysics Data System (ADS)

    Park, Jeong Yeon; Lee, Jeong Won; Heo, Young Moo; Won, Si Tae; Yoon, Gil Sang

    2016-03-01

    The conventional method of making a phosphor layer on the LED package by using a dispensing method is difficult to implement the specific color coordinate, color temperature and optical efficiency because the thickness of the phosphor layer is non-uniform due to precipitation of the phosphor. Besides, the dispensing method consume a large amount of phosphor and silicone to fill the LED package. Thus, studies that manufacture phosphor layer with a uniform thickness such as spray coating, screen printing, electrophoresis are active recently. The purpose of this study is to perform the basic research about the change of the characteristics of phosphor film that is molded with uniform thickness using the phosphor slurry according to various silicone resin and phosphor composition ratio. It is expected to be used as useful information for the fabricating properties when production environment of phosphor layer is changed dispensing method into phosphor film fabrication. In the experiment, it was selected three kinds of methyl-phenyl silicone based resin as the phosphor slurry constituents, and mixed with phosphor various amount of 20 ˜ 60wt% content per one silicone resin. Using this mixed phosphor slurry, it was molded the phosphor film with 300 μm thickness and analyzed the mechanical properties and optical properties of the phosphor film. Finally, the results of this study are presented below: (a) As the phenyl group content is increased, the total heat of reaction need to cure the silicone resin is decrease, and also lower the durometer hardness of the phosphor sheet. On the other hand, it was confirmed that there is no relationship between the phenyl group content in the phosphor film and optical characteristics of the phosphor film. (b) If the amount of the phosphor within the film are increased, then the values of shore hardness and CIE color coordinates are increased gradually but the value of CIE color temperature is decreased gradually in case of being

  19. A self-activated silicate phosphor of Na{sub 5}YZrSi{sub 6}O{sub 18}

    SciTech Connect

    Guan, Ying; Qin, Lin; Huang, Yanlin; Qin, Chuanxiang; Wei, Donglei; Seo, Hyo Jin

    2014-06-01

    Graphical abstract: Self-activated Na{sub 5}YZrSi{sub 6}O{sub 18} shows a bright green luminescence. It presents obvious LLP afterglow with duration time >3 h after the removal of excitation. The substitution of Y{sup 3+} by rare earth ions except Yb{sup 3+} cannot prolong the afterglow. It is proposed that the disorder in the lattices can result in different trap centers attributing to the long last phosphorescence. - Highlights: • Na{sub 5}YZrSi{sub 6}O{sub 18} was firstly developed to be a new bluish green-emitting silicate. • Na{sub 5}YZrSi{sub 6}O{sub 18} presents unusual properties: efficient excitation and longer emission wavelength. • Na{sub 5}YZrSi{sub 6}O{sub 18} shows long-lasting phosphorescence with duration time above 3 h. - Abstract: A new self-activated silicate phosphor of Na{sub 5}YZrSi{sub 6}O{sub 18} was prepared by a solid-state reaction method. The phase formation was confirmed by X-ray powder diffraction measurement. The photoluminescence excitation and emission spectra, X-ray-excited luminescence, decay curves, quantum efficiencies and the color coordinates were investigated. It can be efficiently excited by UV light and X-ray and presents unusual green emission (centered at 475 nm) from Zr{sup 4+} to O{sup 2−} charge transfer transition. Meanwhile, the phosphor shows long-lasting phosphorescence with duration time above 3 h after the removal of excitation. The afterglow curves and thermo-luminescence were measured for pure and rare earth ions (RE = Yb, Er, Ho, Dy, Tb, Sm, Nd) doped Na{sub 5}YZrSi{sub 6}O{sub 18}. The possible defects and the mechanism of long-lasting phosphorescence were suggested on the base of the strong disorder of the multiply cation sites in the lattices.

  20. Goldilocks Catalysts: Computational Insights into the Role of the 3,3' Substituents on the Selectivity of BINOL-Derived Phosphoric Acid Catalysts.

    PubMed

    Reid, Jolene P; Goodman, Jonathan M

    2016-06-29

    BINOL-derived phosphoric acids provide effective asymmetric catalysis for many organic reactions. Catalysts based on this scaffold show a large structural diversity, especially in the 3,3' substituents, and little is known about the molecular requirements for high selectivity. As a result, selection of the best catalyst for a particular transformation requires a trial and error screening process, as the size of the 3,3' substituents is not simply related to their efficacy: the right choice is neither too large nor too small. We have developed an approach to identify and quantify structural features on the catalyst that determine selectivity. We show that the application of quantitative steric parameters (a new measure, AREA(θ), and rotation barrier) to an imine hydrogenation reaction allows the identification of catalyst features necessary for efficient stereoinduction, validated by QM/MM hybrid calculations. PMID:27227372

  1. ELECTROCHEMICAL PROPERTIES, MECHANICAL TESTING, AND GEL MORPHOLOGY STUDY OF PHOSPHORIC ACID-DOPED META-POLYBENZIMIDAZOLE MEMBRANES VIA CONVENTIONALLY IMBIBING AND THE SOL-GEL PROCESS

    SciTech Connect

    Perry, Kelly A; More, Karren Leslie; Benicewicz, Brian

    2009-01-01

    Proton exchange membrane (PEM) research has been directed at phosphoric acid (PA)-doped polybenzimidazole (PBI) membranes since the 1990s. PEM fuel cells based on PA-doped PBI membranes produced via a sol-gel transition process have achieved lifetimes >10,000hrs with low degradation rates. It has been suggested that the gel morphology of the PA-doped PBI membranes is responsible for their excellent electrochemical performance. Thus, a study has been underway to characterize the microstructure of PA-doped PBI membranes, and to correlate structure with performance. However, PA-doped PBI membranes present special challenges for microscopy analysis, as these membranes are extremely sensitive to the electron beam and high vacuum conditions. This paper will discuss and compare the mechanical, electrochemical, and cryo-SEM analyses of PA-doped meta-PBI membranes produced via conventional imbibing and the sol-gel process.

  2. A novel phosphoric acid doped poly(ethersulphone)-poly(vinyl pyrrolidone) blend membrane for high-temperature proton exchange membrane fuel cells

    NASA Astrophysics Data System (ADS)

    Xu, Xin; Wang, Haining; Lu, Shanfu; Guo, Zhibin; Rao, Siyuan; Xiu, Ruijie; Xiang, Yan

    2015-07-01

    A high-temperature proton exchange membrane, poly(ethersulphone)-poly(vinyl pyrrolidone) (PES-PVP) blend membrane is successfully prepared by scalable polymer blending method. The physical properties of blend membrane are characterized by DSC, TG and tensile strength test. The DSC and TG results indicate PES-PVP blend membranes possess excellent thermal stability. After phosphoric acid (PA) doping treatment, the blend membrane shows enhanced proton conductivity. PA doping level and volume swelling ratio of the blend membrane are found to be positively related to the PVP content. A high proton conductivity of 0.21 S/cm is achieved at 180 °C for PA doped PES-PVP 80% with a PA doping level of 9.1. PEM fuel cell based on PA doped PES-PVP 80% membrane shows a high power density of 850 mW/cm2 and outstanding stability at 180 °C without extra humidification.

  3. Growth of thin, c-axis oriented Sr-doped LaP3O9 electrolyte membranes in condensed phosphoric acid solutions

    NASA Astrophysics Data System (ADS)

    Hatada, Naoyuki; Takahashi, Kota; Adachi, Yoshinobu; Uda, Tetsuya

    2016-08-01

    Proton-conducting Sr-doped LaP3O9 has potential application as electrolytes in intermediate temperature fuel cells, but reduction of the electrical resistance of the electrolyte membranes is necessary for practical applications. In this study, we focused on reducing the resistance by reducing the electrolyte thickness, while maintaining a preferable microstructure for proton conduction (c-axis orientation and absence of the small-crystal layer). Thin, c-axis oriented Sr-doped LaP3O9 membranes were successfully obtained in condensed phosphoric acid solutions by a novel "two-step precipitation method". In this method, Sr-doped LaP3O9 powder was artificially deposited on the surface of the carbon paper supports as seeds, and then columnar crystals were grown "downward" in the solutions. We expect that this method will be utilized to produce LaP3O9 electrolyte membranes with lower electrical resistance.

  4. FT-IR spectral, DFT studies and detailed vibrational assignment on N,N',N"-tris(2-aminoethyl)-phosphoric acid triamide.

    PubMed

    Unsalan, O; Szolnoki, B; Toldy, A; Marosi, G

    2012-12-01

    Structure of N,N',N"-tris(2-aminoethyl)-phosphoric acid triamide (TEDAP), which is a phosphorus-containing reactive amine crosslinking agent and flame retardant material as well, identified by Fourier transform infrared (FT-IR) spectroscopy and quantum chemical calculations. The FT-IR spectrum of TEDAP, being a recently synthesized new compound, has been recorded in the 4000-650 cm(-1) region for the first time. The molecular geometry and vibrational wavenumbers of the compound in its ground state have been calculated by using Density Functional Theory (DFT) using B3LYP functional with 6-311++G(d,p) basis set. All calculations were performed with Gaussian09 software. The obtained vibrational wavenumbers and optimized geometric parameters were seen to be in good agreement with the experimental data. Furthermore, assignments of each vibrational mode were interpreted in terms of potential energy distributions (PED) in detail.

  5. Isolation and structural characterization of sugarcane bagasse lignin after dilute phosphoric acid plus steam explosion pretreatment and its effect on cellulose hydrolysis.

    PubMed

    Zeng, Jijiao; Tong, Zhaohui; Wang, Letian; Zhu, J Y; Ingram, Lonnie

    2014-02-01

    The structure of lignin after dilute phosphoric acid plus steam explosion pretreatment process of sugarcane bagasse in a pilot scale and the effect of the lignin extracted by ethanol on subsequent cellulose hydrolysis were investigated. The lignin structural changes caused by pretreatment were identified using advanced nondestructive techniques such as gel permeation chromatography (GPC), quantitative (13)C, and 2-D nuclear magnetic resonance (NMR). The structural analysis revealed that ethanol extractable lignin preserved basic lignin structure, but had relatively lower amount of β-O-4 linkages, syringyl/guaiacyl units ratio (S/G), p-coumarate/ferulate ratio, and other ending structures. The results also indicated that approximately 8% of mass weight was extracted by pure ethanol. The bagasse after ethanol extraction had an approximate 22% higher glucose yield after enzyme hydrolysis compared to pretreated bagasse without extraction.

  6. Shear Bond Strength of an Etch-and-rinse Adhesive to Er:YAG Laser- and/or Phosphoric Acid-treated Dentin

    PubMed Central

    Davari, Abdolrahim; Sadeghi, Mostafa; Bakhshi, Hamid

    2013-01-01

    Background and aims. Er:YAG laser irradiation has been claimed to improve the adhesive properties of dentin; therefore, it has been proposed as an alternative to acid etching. The aim of this in vitro study was to investigate the shear bond strength of an etch-and-rinse adhesive system to dentin surfaces following Er:YAG laser and/or phosphoric acid etching. Materials and methods. The roots of 75 sound maxillary premolars were sectioned below the CEJ and the crowns were embedded in auto-polymerizing acrylic resin with the buccal surfaces facing up. The buccal surfaces were ground using a diamond bur and polished until the dentin was exposed; the samples were randomly divided into five groups (n=15) according to the surface treatment: (1) acid etching; (2) laser etching; (3) laser etching followed by acid etching; (4) acid etching followed by laser etching and (5) no acid etching and no laser etching (control group). Composite resin rods (Point 4, Kerr Co) were bonded to treated dentin surfaces with an etch-and-rise adhesive system (Optibond FL, Kerr Co) and light-cured.After storage for two weeks at 37°C and 100% humidity and then thermocycling, bond strength was measured with a Zwick Universal Testing Machine at a crosshead speed of 1 mm/min. Data was analyzed using parametric and non-parametric tests (P<0.05). Results. Mean shear bond strength for acid etching (20.1±1.8 MPa) and acid+laser (15.6±3.5 MPa) groups were significantly higher than those for laser+acid (15.6±3.5 MPa), laser etching (14.1±3.4 MPa) and control (8.1±2.1 MPa) groups. However, there were no significant differences between acid etching and acid+laser groups, and between laser+acid and laser groups. Conclusion. When the cavity is prepared by bur, it is not necessary to etch the dentin surface by Er:YAG laser following acid etching and acid etching after laser etching. PMID:23875083

  7. DISTRIBUTION OF LANTHANIDE AND ACTINIDE ELEMENTS BETWEEN BIS-(2-ETHYLHEXYL)PHOSPHORIC ACID AND BUFFERED LACTATE SOLUTIONS CONTAINING SELECTED COMPLEXANTS

    SciTech Connect

    Rudisill, Tracy S.; Diprete, David P.; Thompson, Major C.

    2013-04-15

    With the renewed interest in the closure of the nuclear fuel cycle, the TALSPEAK process is being considered for the separation of Am and Cm from the lanthanide fission products in a next generation reprocessing plant. However, an efficient separation requires tight control of the pH which likely will be difficult to achieve on a large scale. To address this issue, we measured the distribution of lanthanide and actinide elements between aqueous and organic phases in the presence of complexants which were potentially less sensitive to pH control than the diethylenetriaminepentaacetic (DTPA) used in the process. To perform the extractions, a rapid and accurate method was developed for measuring distribution coefficients based on the preparation of lanthanide tracers in the Savannah River National Laboratory neutron activation analysis facility. The complexants tested included aceto-, benzo-, and salicylhydroxamic acids, N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN), and ammonium thiocyanate (NH{sub 4}SCN). The hydroxamic acids were the least effective of the complexants tested. The separation factors for TPEN and NH{sub 4}SCN were higher, especially for the heaviest lanthanides in the series; however, no conditions were identified which resulted in separations factors which consistently approached those measured for the use of DTPA.

  8. Combining octyl(phenyl)-N,N-diisobutyl-carbamoylmethylphosphine oxide and bis-(2-ethylhexyl)phosphoric acid extractants for recovering transuranic elements from irradiated nuclear fuel

    SciTech Connect

    Lumetta, Gregg J.; Carter, Jennifer C.; Gelis, Artem V.; Vandegrift, George F.

    2009-10-14

    Advanced concepts for closing the nuclear fuel cycle include separating Am and Cm from other fuel components. Separating these elements from the lanthanide elements at an industrial scale remains a significant technical challenge. We describe here a chemical system in which a neutral extractant--octyl(phenyl)-N,N-diisobutyl-carbamoylmethyl-phosphine oxide (CMPO)--is combined with an acidic extractant--bis-(2-ethylhexyl)phosphoric acid (HDEHP)--to form a single process solvent (with dodecane as the diluent) for separating Am and Cm from the other components of irradiated nuclear fuel. Continuous variation experiments in which the relative CMPO and HDEHP concentrations are varied indicate a synergistic relationship between the two extractants in the extraction of Am from buffered diethylenetriaminepentaacetic acid (DTPA) solutions. A solvent mixture consisting or 0.1 M CMPO + 1 M HDEHP in dodecane offers acceptable extraction efficiency for the trivalent lanthanides and actinides from 1 M HNO3 while maintaining good lanthanide/actinide separation factors in the stripping regime (buffered DTPA solutions with pH 3.5 to 4). Using citrate buffer instead of lactate buffer results in improved lanthanide/actinide separation factors.

  9. Polarization selection rules and optical transitions in terbium activated yttrium tantalate phosphor under x-ray, vacuum-ultraviolet, and ultraviolet excitations

    SciTech Connect

    Nazarov, Mihail; Tsukerblat, Boris; Byeon, Clare Chisu; Arellano, Ivan; Popovici, Elisabeth-Jeanne; Noh, Do Young

    2009-01-01

    The terbium-activated yttrium tantalite (YTaO4:Tb{sup 3{sup +}}) phosphor is of great interest due to the interesting spectroscopic properties of rare earth ions in crystals and also practical use in x-ray imaging. Using the group-theoretical approach, we analyze the selection rules for the transition between Stark components of Tb{sup 3{sup +}} in symmetry of the actual crystal field and the polarization for the allowed transitions. The luminescence upon UV, vacuum-ultraviolet (VUV), and x-ray excitation is presented and discussed. The YTaO4:Tb{sup 3{sup +}} phosphors are found to be efficient VUV-excited luminescent materials that could be used not only in x-ray intensifying screens, but also in mercury-free fluorescent lamps or plasma display panels.

  10. a New Red Phosphor of the Mn Activated Non-Stoichiometric Strontium Aluminate 3SrO•5Al2O3 for High Color Rendering White Leds

    NASA Astrophysics Data System (ADS)

    Chen, Lei; Zhang, Yao; Liu, Fayong; Deng, Xiaorong; Xue, Shaochan; Luo, Anqi; Jiang, Yang; Chen, Shifu; Zhang, Wenhua

    2013-06-01

    A new red phosphor of strontium aluminate activated by Mn4+ was developed for high color rendering and warm white light-emitting diodes. The phosphor composition and conditions for synthesis were optimized through solid-state reaction. Meanwhile, the structure and morphology were investigated with XRD and SEM analysis. The results show that the 3SrO•5Al2O3 activated by 0.0005 M Mn fired at 1300°C in air ambient by adopting 2.5 wt.% AlF3 as flux exhibits most efficient luminescence. A white LED device prototype with CIE (0.3291, 0.3571), CCT 5639 K, CRI Ra 92.6, and efficacy 63 lm/W driven at 20 mA has been packaged by pre-coating the red phosphor combined with a yellow one Y3Al5O12:Ce3+ on a blue InGaN chip. The analysis of critical distance and luminescence quench reveal that the mechanism of energy transfer for luminescence is through dipole-dipole interaction.

  11. A single-phase full-color phosphor based on Ba3MgSi2O8 co-activated with Eu2+, Tb3+, and Mn2+

    NASA Astrophysics Data System (ADS)

    Birkel, Alexander; DeCino, Nicholas A.; Cozzan, Clayton; Mikhailovsky, Alexander A.; Hong, Byung-Chul; Seshadri, Ram

    2015-10-01

    We present a rapid and energy-efficient microwave-assisted approach to prepare a single-phase full-color phosphor based on Ba3MgSi2O8. The samples were prepared using a citric acid based sol-gel preparation pathway with a microwave-assisted heating step, which reduces the time required for the final heat treatment to less than 30 min. Thermogravimetric analysis was utilized to optimize the solution-based preparation prior to microwave heating. The structural properties of the obtained luminescent materials have been thoroughly investigated by means of X-ray powder diffraction and Rietveld analyses. To study the optical behavior, the excitation and emission spectra were recorded. Full-color emission is achieved using Eu2+ (blue), Tb3+ (green), and Mn2+ (red) as the activator ions. The thermally robust emission was investigated using temperature-dependent luminescence spectroscopy. The energy-transfer processes within the samples were studied using time-dependent spectroscopy, and the quantum yield of this true color phosphor as a function of the composition was determined.

  12. Picking the right tool for the job – phosphor-proteomics of egg activation

    PubMed Central

    Wessel, Gary M.

    2016-01-01

    Eggs are the rarest cell in the human body, yet their study is essential for the fields of fertility, reproduction, and fetal health. Guo et al use a “surrogate” animal to discover the phophoproteomic pathways involved in egg activation. With datasets of several thousand phophosites on 2500 different proteins, these investigators have defined new pathways, connections to pathways, and priorities in searches for how eggs are activated at fertilization. These results in a sea urchin are now transposable to mammals for testing on a per candidate strategy. PMID:26573262

  13. Experiments and simulation on diffusion and activation of codoped with arsenic and phosphorous germanium

    SciTech Connect

    Tsouroutas, P.; Tsoukalas, D.; Bracht, H.

    2010-07-15

    We report arsenic and phosphorus diffusion experiments and activation related phenomena in codoped germanium substrates utilizing conventional thermal annealing. Chemical profiles were obtained by secondary ion mass spectroscopy, sheet resistance was estimated by the Van der Pauw method. Our study covers the temperature range from 600 to 750 deg. C. We accurately described the dopant profiles with a quadratic dependence of the dopants diffusion coefficient on the free electron concentration. In our simulations we considered the dopant pile-up near the surface and dopant loss owing to outdiffusion during the annealing. Although the double donor codoping technique exhibited no advantage over monodoping with P concerning the level of activation and junction depth, it was interesting to observe the different diffusion behavior of the two dopants. Whereas the diffusion of As indicates a retardation under codoping the diffusion of P remains either unaffected or is slightly enhanced by codoping. The activation level of the codoped samples remains lower compared to the respective monodoped samples, except for the highest annealing temperature.

  14. Organic Fluorescent Dyes Supported on Activated Boron Nitride: A Promising Blue Light Excited Phosphors for High-Performance White Light-Emitting Diodes

    NASA Astrophysics Data System (ADS)

    Li, Jie; Lin, Jing; Huang, Yang; Xu, Xuewen; Liu, Zhenya; Xue, Yanming; Ding, Xiaoxia; Luo, Han; Jin, Peng; Zhang, Jun; Zou, Jin; Tang, Chengchun

    2015-02-01

    We report an effective and rare-earth free light conversion material synthesized via a facile fabrication route, in which organic fluorescent dyes, i.e. Rhodamine B (RhB) and fluorescein isothiocyanate (FITC) are embedded into activated boron nitride (αBN) to form a composite phosphor. The composite phosphor shows highly efficient Förster resonance energy transfer and greatly improved thermal stability, and can emit at broad visible wavelengths of 500-650 nm under the 466 nm blue-light excitation. By packaging of the composite phosphors and a blue light-emitting diode (LED) chip with transparent epoxy resin, white LED with excellent thermal conductivity, current stability and optical performance can be realized, i.e. a thermal conductivity of 0.36 W/mk, a Commission Internationale de 1'Eclairage color coordinates of (0.32, 0.34), and a luminous efficiency of 21.6 lm.W-1. Our research opens the door toward to the practical long-life organic fluorescent dyes-based white LEDs.

  15. Organic Fluorescent Dyes Supported on Activated Boron Nitride: A Promising Blue Light Excited Phosphors for High-Performance White Light-Emitting Diodes

    PubMed Central

    Li, Jie; Lin, Jing; Huang, Yang; Xu, Xuewen; Liu, Zhenya; Xue, Yanming; Ding, Xiaoxia; Luo, Han; Jin, Peng; Zhang, Jun; Zou, Jin; Tang, Chengchun

    2015-01-01

    We report an effective and rare-earth free light conversion material synthesized via a facile fabrication route, in which organic fluorescent dyes, i.e. Rhodamine B (RhB) and fluorescein isothiocyanate (FITC) are embedded into activated boron nitride (αBN) to form a composite phosphor. The composite phosphor shows highly efficient Förster resonance energy transfer and greatly improved thermal stability, and can emit at broad visible wavelengths of 500–650 nm under the 466 nm blue-light excitation. By packaging of the composite phosphors and a blue light-emitting diode (LED) chip with transparent epoxy resin, white LED with excellent thermal conductivity, current stability and optical performance can be realized, i.e. a thermal conductivity of 0.36 W/mk, a Commission Internationale de 1'Eclairage color coordinates of (0.32, 0.34), and a luminous efficiency of 21.6 lm·W−1. Our research opens the door toward to the practical long-life organic fluorescent dyes-based white LEDs. PMID:25682730

  16. Phosphorous removal in batch systems using ferric chloride in the presence of activated sludges.

    PubMed

    Caravelli, Alejandro H; Contreras, Edgardo M; Zaritzky, Noemí E

    2010-05-15

    The objectives of this work were: (a) to analyze the effect of alkalinity, pH and initial Fe:P molar ratio (Fe(0):P(0)) on the precipitation of orthophosphate using ferric chloride in the presence of activated sludge in order to represent conditions of simultaneous precipitation, and in exhausted wastewater to simulate conditions of post-precipitation, (b) to compare the experimental results with predictions obtained from a chemical equilibrium model, and (c) to propose a mechanistic model to determine the dose of coagulant required to achieve a given orthophosphate removal degree at constant pH. Results showed that the presence of biomass did not affect the orthophosphate precipitation; however, addition of ferric chloride caused a drop of pH to values not compatible with the normal activity of activated sludges. For this reason, the wastewater was supplemented with NaHCO(3); when 1gL(-1) NaHCO(3) was added, orthophosphate removals higher than 97% and pH above 6.2 were obtained using Fe(0):P(0)=1.9. Precipitation assays at constant pH showed that Fe(III) hydrolysis and FePO(4) precipitation reaction compete with each other. Calculations using a chemical equilibrium model (CHEAQS) predicted that ferric phosphate precipitation should not take place if pH is higher than about 7.8. However, experimental results showed that ferric phosphate precipitation occurred even at pH 9. For this reason, a mechanistic model was proposed to predict orthophosphate concentrations as a function of Fe(0):P(0) at constant pH. The model can be applied to calculate the minimum Fe(III) concentration required to achieve a given discharge limit for orthophosphate as a function of its initial concentration and pH.

  17. Spatial variability of dissolved phosphorous concentrations and alkaline phosphatase activity in the East China Sea

    NASA Astrophysics Data System (ADS)

    Liu, H.; Chang, J.; Ho, T.; Gong, G.

    2010-12-01

    The concentrations of dissolved inorganic phosphorus (DIP) and alkaline phosphatase activity (APA) have been determined at about 25 sampling stations in the East China Sea since 2003. The stations are mainly distributed from the Changjiang river mouth to northern Taiwan and east to the shelf break. In addition to the Changjiang discharge, we have found a specific nutrient source around a coastal site (122° 2’30’’ E, 28° 40’ N). Elevated DIP and nitrate concentrations have been constantly observed around the sampling station for 8 years, where the surface DIP concentrations are generally around 0.3 µM. The nutrient source may either originate from ground water discharge or coastal upwelling, where lower temperature has been observed in the water column around the station. In general, APA has been negatively correlated with DIP concentrations in the studies sites, with lowest APA around the high DIP station and the Changjiang river mouth.

  18. The role of activator concentration and precipitate formation on optical and dosimetric properties of KCl:Eu{sup 2+} storage phosphor detectors

    SciTech Connect

    Hansel, Rachael A.; Xiao, Zhiyan; Hu, Yanle; Green, Olga; Yang, Deshan; Harold Li, H.

    2013-09-15

    Purpose: The activator ion (Eu{sup 2+} in KCl:Eu{sup 2+}) plays an important role in the photostimulated luminescence (PSL) mechanism of storage phosphor radiation detectors. In order to design an accurate, effective, and robust detector, it is important to understand how the activator ion concentration affects the structure and, consequently, radiation detection properties of KCl:Eu{sup 2+}.Methods: Potassium chloride pellets were fabricated with various amounts of europium dopant (0.01–5.0 mol.% Eu{sup 2+}). Clinical radiation doses were given with a 6 MV linear accelerator. Radiation doses larger than 100 Gy were given with a {sup 137}Cs irradiator. Dose response curves, radiation hardness, and temporal signal stability were measured using a laboratory PSL readout system. The crystal structure of the material was studied using x ray diffraction and luminescence spectroscopy.Results: The most intense PSL signal was from samples with 1.0 mol.% Eu. However, samples with concentrations higher than 0.05 mol.% Eu exhibited significant degradation in PSL intensity for cumulated doses larger than 3000 Gy. Structural and luminescence spectroscopy showed clear evidence of precipitate phases within the KCl lattice, especially for high activator concentrations. Analysis of PL emission spectra showed that interactions between Eu-V{sub c} dipoles and Eu-V{sub c} trimers could explain trends in PSL sensitivity and radiation hardness observations.Conclusions: The concentration of the activator ion (Eu{sup 2+}) significantly affects radiation detection properties of the storage phosphor KCl:Eu{sup 2+}. An activator concentration between 0.01 and 0.05 mol.% Eu in KCl:Eu{sup 2+} storage phosphor detectors is recommended for linear dose response, good PSL sensitivity, predictable temporal stability, and high reusability for megavoltage radiation detection.

  19. Organic acids inhibit the formation of pyromorphite and Zn-phosphate in phosphorous amended Pb- and Zn-contaminated soil.

    PubMed

    Debela, F; Arocena, J M; Thring, R W; Whitcombe, T

    2013-02-15

    Pyromorphite (PY) and some zinc phosphates (Zn-P) are very sparingly soluble minerals and hence can immobilize Pb and Zn in contaminated soils. However, mechanisms leading to the poor efficiency of PY and Zn-P formation in contaminated soils amended with P still remain unclear. We studied the influence of two low molecular weight organic acids (LMWOA) - oxalic acid and citric acid and diethylene triamine pentaacetic acid (DTPA) - in PY and Zn-P formation in a P-amended contaminated soil. Despite the high levels of metals (∼4% Pb and 21% Zn) in the study soil, the addition of up to 1% inorganic P transformed only up to 37% and 17% of the total Pb and Zn to PY and Zn-P, respectively. Semi-quantitative estimates from a linear combination fitting of X-ray absorption near edge spectra (LC-XANES fitting) showed that the formation of PY decreased from 37% to 3% of the total Pb in the presence of oxalic acid and the addition of 1% P. The reduced PY formation may be associated with the increase in organic-bound Pb from 9% to 54% and decrease in carbonate associated Pb from 42% to 12% with oxalic acid addition as indicated by a chemical sequential extraction (SE) technique. Citric acid seemed to have a less adverse effect in PY formation than oxalic acid. Our data also suggests both oxalic and citric acids have less adverse effects on the efficiency of Zn-P formation. From this study we conclude that the abundance of LMWOA in soil environments can be one factor contributing to the poor efficiency of P amendments practices to effectively immobilize Pb and Zn in metal contaminated soils.

  20. Synthesis and photoluminescence of Tb{sup 3+} Activated NaY(WO{sub 4}){sub 2} phosphors

    SciTech Connect

    Liu, Xiaohua; Xiang, Wendou; Chen, Fengming; Zhang, Wei; Hu, Zhengfa

    2012-11-15

    Graphical abstract: The phosphor powders of NaY(WO{sub 4}){sub 2}:Tb{sup 3+} were prepared by solid state reaction. The dependence of luminescence intensity on the Tb{sup 3+} concentration was investigated. Highlights: ► We synthesize NaY(WO{sub 4}){sub 2}:Tb{sup 3+} phosphors by the solid-state reaction technique. ► We observe and explain the blue shifting of excitation peak positions of CTBs. ► The PL from {sup 5}D{sub 3} level become less probable with increasing the Tb{sup 3+} content. ► The PL intensity increases with Tb{sup 3+} content without concentration quenching. ► NaY(WO{sub 4}){sub 2}:Tb{sup 3+} has potential application as a green emitting phosphor in lamps. -- Abstract: The novel yellowish green phosphor powders of NaY(WO{sub 4}){sub 2} doped with Tb{sup 3+} were prepared by solid-state reaction. The powder samples were characterized by X-ray diffraction and photoluminescence. X-ray diffraction analysis showed that the phosphors sintered at 900 °C for 6 h were a pure NaY(WO{sub 4}){sub 2} phase for all the Tb{sup 3+} doping concentrations. The room temperature excitation spectra vary with the Tb{sup 3+} concentration and consist of an intense charge transfer band of WO{sub 4}{sup 2−} group and weak intra-4f{sup 8} transition absorption peaks of Tb{sup 3+} ions. The photoluminescence spectra, excited at the peak wavelengths of charge transfer bands, consist of the characteristic Tb{sup 3+} emission transitions from {sup 5}D{sub 3} and {sup 5}D{sub 4} excited levels to {sup 7}F{sub J} (J = 3–6) levels. The dependence of luminescence intensity on the Tb{sup 3+} concentration in NaY(WO{sub 4}){sub 2}:Tb phosphors was investigated.

  1. The effect of ethoxyquin on the quality of ground poultry mortality carcasses preserved by lactic acid fermentation and phosphoric acid stabilization.

    PubMed

    Middleton, T F; Ferket, P R; Boyd, L C

    2001-08-01

    Fermentation and acidification have been shown to preserve the protein quality of ground poultry coproducts, but the effects of these processes on their lipid stability are unknown, especially in the presence of an antioxidant. To evaluate the effects of these treatments on lipid quality, ground poultry mortality carcasses, with and without an addition of 500 ppm ethoxyquin, were stabilized for 14 and 45 d by lactic acid fermentation or acidification with 2.76, 5.07, 7.35, or 9.65% feed-grade H3PO4. Ethoxyquin treatment significantly (P < 0.001) improved the oxidative stability of lipids from all storage treatments. However, the addition of ethoxyquin increased (P < 0.001) the levels of volatile N (VN) from 2.51 to 3.18% in products stored for 45 d and resulted in an increase (P < 0.001) in free fatty acids in all ensiled products. Ethoxyquin addition had no effect (P > 0.120) on the fatty acid profile of products stored for 14 d but significantly increased (P < 0.001) the levels of stearic (C18:0) and arachidonic acids (C20:4) in products stored for 45 d. In this experiment, the addition of ethoxyquin to preservation systems for the short-term storage of poultry mortality carcasses improved the lipid quality of the ground material without compromising the protein quality or affecting proximate analysis parameters. However, the increased oxidative stability of mortality silage materials that contain ethoxyquin may contribute to enhanced microbial or enzymatic activities that result in proteolytic or lypolytic breakdown products following longer periods of storage. PMID:11495468

  2. Features of the Thermodynamics of Trivalent Lanthanide/Actinide Distribution Reactions by Tri-n-Octylphosphine Oxide and Bis(2-EthylHexyl) Phosphoric Acid

    SciTech Connect

    Travis S. Grimes; Peter R. Zalupski

    2014-11-01

    A new methodology has been developed to study the thermochemical features of the biphasic transfer reactions of trisnitrato complexes of lanthanides and americium by a mono-functional solvating ligand (tri-n-octyl phosphine oxide - TOPO). Stability constants for successive nitrato complexes (M(NO3)x3-x (aq) where M is Eu3+, Am3+ or Cm3+) were determined to assist in the calculation of the extraction constant, Kex, for the metal ions under study. Enthalpies of extraction (?Hextr) for the lanthanide series (excluding Pm3+) and Am3+ by TOPO have been measured using isothermal titration calorimetry. The observed ?Hextr were found to be constant at ~29 kJ mol-1across the series from La3+-Er3+, with a slight decrease observed from Tm3+-Lu3+. These heats were found to be consistent with enthalpies determined using van ’t Hoff analysis of temperature dependent extraction studies. A complete set of thermodynamic parameters (?G, ?H, ?S) was calculated for Eu(NO3)3, Am(NO3)3 and Cm(NO3)3 extraction by TOPO and Am3+ and Cm3+ extraction by bis(2-ethylhexyl) phosphoric acid (HDEHP). A discussion comparing the energetics of these systems is offered. The measured biphasic extraction heats for the transplutonium elements, ?Hextr, presented in these studies are the first ever direct measurements offered using two-phase calorimetric techniques.

  3. Central metal ion exchange in a coordination polymer based on lanthanide ions and di(2-ethylhexyl)phosphoric acid: exchange rate and tunable affinity.

    PubMed

    Tasaki-Handa, Yuiko; Abe, Yukie; Ooi, Kenta; Tanaka, Mikiya; Wakisaka, Akihiro

    2014-01-01

    In this paper the exchange of lanthanide(III) ions (Ln(3+)) between a solution and a coordination polymer (CP) of di(2-ethylhexyl)phosphoric acid (Hdehp), [Ln(dehp)3], is studied. Kinetic and selectivity studies suggest that a polymeric network of [Ln(dehp)3] has different characteristics than the corresponding monomeric complex. The reaction rate is remarkably slow and requires over 600 h to reach in nearly equilibrium, and this can be explained by the polymeric crystalline structure and high valency of Ln(3+). The affinity of the exchange reaction reaches a maximum with the Ln(3+) possessing an ionic radius 7% smaller than that of the central Ln(3+), therefore, the affinity of the [Ln(dehp)3] is tunable based on the choice of the central metal ion. Such unique affinity, which differs from the monomeric complex, can be explained by two factors: the coordination preference and steric strain caused by the polymeric structure. The latter likely becomes predominant for Ln(3+) exchange when the ionic radius of the ion in solution is smaller than the original Ln(3+) by more than 7%. Structural studies suggest that the incoming Ln(3+) forms a new phase though an exchange reaction, and this could plausibly cause the structural strain.

  4. Response surface optimization of corn stover pretreatment using dilute phosphoric acid for enzymatic hydrolysis and ethanol production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dilute H3PO4 (0.0 - 2.0%, v/v) was used to pretreat corn stover (10%, w/w) for conversion to ethanol. Pretreatment conditions were optimized for temperature, acid loading, and time using a central composite design. Optimal pretreatment conditions were chosen to promote sugar yields following enzym...

  5. ELECTRIC POWER GENERATION USING A PHOSPHORIC ACID FUEL CELL ON A MUNICIPAL SOLID WASTE LANDFILL GAS STREAM

    EPA Science Inventory

    The report gives results of tests to verify the performance of a landfill gas pretreatment unit (GPU) and a phorsphoric acid fuel cell system. The complete system removes contaminants from landfill gas and produces electricity for on-site use or connection to an electric grid. Th...

  6. Response surface optimization of corn stover pretreatment using dilute phosphoric acid for enzymatic hydrolysis and ethanol production.

    PubMed

    Avci, Ayse; Saha, Badal C; Dien, Bruce S; Kennedy, Gregory J; Cotta, Michael A

    2013-02-01

    Dilute H(3)PO(4) (0.0-2.0%, v/v) was used to pretreat corn stover (10%, w/w) for conversion to ethanol. Pretreatment conditions were optimized for temperature, acid loading, and time using central composite design. Optimal pretreatment conditions were chosen to promote sugar yields following enzymatic digestion while minimizing formation of furans, which are potent inhibitors of fermentation. The maximum glucose yield (85%) was obtained after enzymatic hydrolysis of corn stover pretreated with 0.5% (v/v) acid at 180°C for 15min while highest yield for xylose (91.4%) was observed from corn stover pretreated with 1% (v/v) acid at 160°C for 10min. About 26.4±0.1g ethanol was produced per L by recombinant Escherichia coli strain FBR5 from 55.1±1.0g sugars generated from enzymatically hydrolyzed corn stover (10%, w/w) pretreated under a balanced optimized condition (161.81°C, 0.78% acid, 9.78min) where only 0.4±0.0g furfural and 0.1±0.0 hydroxylmethyl furfural were produced.

  7. Dicationic ion-pairing of phosphoric acid diesters post-liquid chromatography and subsequent determination by electrospray positive ionization-tandem mass spectrometry.

    PubMed

    Chu, Shaogang; Chen, Da; Letcher, Robert J

    2011-11-01

    Several organophosphate triesters are widely used as flame retardants and can be metabolized to dibutyl (DBP), diphenyl (DPhP), di(2-ethylhexyl) (DEHP) and di(1,3-dichloro-2-propyl) (or bis(1,3-dichloro-2-propyl); DDCPP) phosphoric acid, respectively. A highly sensitive liquid chromatography-electrospray ionization(+)-triple quadrupole mass spectrometry (LC-ESI(+)-QQQ-MS/MS) based analysis method was presently developed. In this method the target compounds were separated with a C(18)-based reversed phase LC column, and decamethonium hydroxide (dicatonic reagent) was introduced post-LC to form ion-pairs, which were subsequently detected by ESI(+). For the phosphate acid diester ion-pairs, the mass spectra showed the most abundant ion to be [(CH(3))(2)N(CH(2))(10)N(CH(3))(3)](+), with lesser abundances of [[M-H](-)[(CH(3))(3)N(CH(2))(9)CH(2)](2+)](+) and [CH(2)CH(CH(2))(8)N(CH(3))(3)](+). For DDCPP, the fragment ions of [[Cl](-)[(CH(3))(3)N(CH(2))(10)N(CH(3))(3)](2+)](+) and [[Cl](-)[(CH(3))(3)N(CH(2))(9)CH(2)](2+)](+) could also be observed. The limits of quantitation (LOQs) by LC-ESI(+)-MS/MS (based on multiple reaction monitoring) were 0.14, 0.03, 0.14 and 0.02 ng/mL for DPhP, DBP, DDCPP and DEHP, respectively. The response was highly linearly correlated (r>0.995) with concentration over the range of the LOD to 1000 ng/mL. The matrix effect on ESI+ was negligible for the samples in experiment of in vitro metabolism using rat liver microsomes. PMID:21945623

  8. Acid Rain: Activities for Science Teachers.

    ERIC Educational Resources Information Center

    Johnson, Eric; And Others

    1983-01-01

    Seven complete secondary/college level acid rain activities are provided. Activities include overview; background information and societal implications; major concepts; student objectives; vocabulary/material lists; procedures; instructional strategies; and questions/discussion and extension suggestions. Activities consider effects of acid rain on…

  9. The effect of phosphoric acid concentration on the synthesis of nano-whiskers of calcium metaphosphate by chemical precipitation Method

    NASA Astrophysics Data System (ADS)

    Yao, Nengjian; Zhang, Yin; Kong, Deshuang; Zhu, Jianping; Tao, Yaqiu; Qiu, Tai

    2011-10-01

    Calcium metaphosphate (CMP) nano-whiskers were produced by a chemical precipitation method. In order to produce nano-powders, CMP was prepared by the mixing of two precursors, calcium oxide (CaO) and phosphate acid (H3PO4). Sparingly soluble chemicals, the Ca/P ratio of the mixture was set to be 0.50 to produce stoichiometric CMP, were chemical agitated in phosphate acid solution. At least 3 hours of pre-hydrolysis of phosphorus precursor were required to obtain CMP phase. The CMP powders were dried in a drying oven at 60 °C for 7 days and then followed by a heat treatment at 390 °C for 8hours. The obtained powder was analyzed using XRD, XRF, FT-IR, SEM, TG-DTA, Zeta Potential Meter, Specific Surface Area, and Particle Size Analyzer. The results showed that obtained CMP nano-whiskers have a significantly powder characteristics.

  10. Eu(2+)-Activated Phase-Pure Oxonitridosilicate Phosphor in a Ba-Si-O-N System via Facile Silicate-Assisted Routes Designed by First-Principles Thermodynamic Simulation.

    PubMed

    Yun, Young Jun; Kim, Jin Kyu; Ju, Ji Young; Choi, Seul Ki; Park, Woon Ik; Jung, Ha-Kyun; Kim, Yongseon; Choi, Sungho

    2016-09-01

    Eu(2+)-activated single phase Ba(2+)-oxonitridosilicate phosphors were prepared under a mild synthetic condition via silicate precursors, and their luminescent properties were investigated. Both the preferred oxonitridosilicate formation as for the available host compounds and thermodynamic stability within the Ba-Si-O-N system were elucidated in detail by the theoretical simulation based on the first-principles density functional theory. Those results can visualize the optimum synthetic conditions for Eu(2+)-activated highly luminescent Ba(2+)-oxonitridosilicates, especially Ba3Si6O12N2, as promising conversion phosphors for white LEDs, including Ba3Si6O9N4 and BaSi2O2N2 phases. To prove the simulated design rule, we synthesized the Ba3Si6O12N2:Eu(2+) phosphor using various silicate precursors, Ba2Si4O10, Ba2Si3O8, and BaSiO3, in a carbothermal reduction ambient and finally succeeded in obtaining a phase of pure highly luminescent oxonitridosilicate phosphor without using any solid-state nitride addition and/or high pressure synthetic procedures. Our study provides useful guidelines for robust synthetic procedures for developing thermally stable rare-earth-ion activated oxonitridosilicate phosphors and an established simulation method that can be effectively applied to other multigas systems. PMID:27518370

  11. Separation of berkelium (IV) from trivalent transplutonium elements on ion-exchangers in solutions of phosphoric acid

    SciTech Connect

    Guseva, L.I.; Stepushkina, V.V.; Tikhomirova, G.S.

    1985-01-01

    The dependences of Am, Cm, Bk, Cf and Es behavior on anion- and cation-exchangers in solutions of 0.1-8.0 M H/sub 3/PO/sub 4/ on acid concentration and oxidant content in solution (KBrO/sub 3/) or in resin (PbO/sub 2/) have been studied. Significant differences in distribution coefficients of Bk and other transplutonium elements (TPE) have been found that can be explained by Bk oxidation to the tetravalent state. A simple and effective method of Bk (IV) separation from trivalent TPE has been developed. The method was applied to the isolation of isotopes Bk-249 and Bk-250; the purification factor of Bk (IV) from other TPE is 10/sup 4/-10/sub 6/ per cycle. The possibility of Bk separation from bromate and phosphate ions by its sorption on a cation-exchanger from diluted H/sub 3/PO/sub 4/ solutions with subsequent desorption by the mineral acid has been shown. 20 references, 8 figures.

  12. Catalytic cracking of C5 raffinate to light olefins over phosphorous-modified microporous and mesoporous ZSM-5.

    PubMed

    Lee, Joongwon; Hong, Ung Gi; Hwang, Sunhwan; Youn, Min Hye; Song, In Kyu

    2013-11-01

    Phosphorous-modified microporous and mesoporous ZSM-5 catalysts (XP/C-ZSM5) were prepared with a variation of phosphorous content (X = 0.17, 0.3, 0.7, 1.4, and 2.7 wt%), and they were applied to the production of light olefins (ethylene and propylene) through catalytic cracking of C5 raffinate. The effect of phosphorous content on the physicochemical properties and catalytic activities of XP/C-ZSM5 catalysts was investigated. It was revealed that physicochemical properties of XP/C-ZSM5 catalysts were strongly influenced by phosphorous content. Strong acidity of XP/C-ZSM5 catalysts decreased with increasing phosphorous content. In the catalytic cracking of C5 raffinate, both conversion of C5 raffinate and yield for light olefins (ethylene and propylene) showed volcano-shaped curves with respect to strong acidity. This result indicates that strong acidity of XP/C-ZSM5 catalysts played an important role in determining the catalytic performance in the catalytic cracking of C5 raffinate. Among the catalysts tested, 0.3P/C-ZSM5 catalyst with moderate strong acidity showed the best catalytic performance.

  13. Thermopressurized diluted phosphoric acid pretreatment of ligno(hemi)cellulose to make free sugars and nutraceutical oligosaccharides.

    PubMed

    Tiboni, Marcela; Grzybowski, Adelia; Baldo, Gizele Rejane; Dias, Edson Flausino; Tanner, Robert D; Kornfield, Julia Ann; Fontana, José Domingos

    2014-06-01

    Ligno(hemi)cellulosics (L(h)Cs) as sugarcane bagasse and loblolly pine sawdust are currently being used to produce biofuels such as bioethanol and biobutanol through fermentation of free sugars that are often obtained enzymatically. However, this bioconversion requires a pretreatment to solubilize the hemicellulose fractions, thus facilitating the action of the cellulolytic enzymes. Instead of the main free monosaccharides used in these current models, the modulation of thermopressurized orthophosphoric acid as a pretreatment, in the ranges of 3-12 atm and pH 1.5-2.5, can produce nondigestible oligosaccharides (NDOS) such as xylo-oligosaccharides (XOS) because heteroxylan is present in both types of hardwood and softwood hemicelluloses. A comparative thin-layer chromatographic analysis of the hydrolytic products showed the best conditions for NDOS production to be 7 atm/water, pH 2.25 and 2.50, and 8.5 atm/water for both sources. Particular hydrolysates from 7 atm (171 °C) at pHs 2.25 and 2.50 both for cane bagasse and pine sawdust, with respective oligosaccharide contents of 57 and 59 %, once mixed in a proportion of 1:1 for each plant source, were used in vitro as carbon sources for Bifidobacterium or Lactobacillus. Once both bacteria attained the stationary phase of growth, an unforeseen feature emerged: the preference of B. animalis for bagasse hydrolysates and, conversely, the preference of L. casei for pine hydrolysates. Considering the fact that nutraceutical oligosaccharides from both hemicelluloses correspond to higher value-added byproducts, the technology using a much diluted thermopressurized orthophosphoric acid pretreatment becomes an attractive choice for L(h)Cs. PMID:24747989

  14. Features of the thermodynamics of trivalent lanthanide/actinide distribution reactions by tri-n-octylphosphine oxide and bis(2-ethylhexyl) phosphoric acid.

    PubMed

    Grimes, Travis S; Zalupski, Peter R; Martin, Leigh R

    2014-11-01

    A new methodology has been developed to study the thermochemical features of the biphasic transfer reactions of trisnitrato complexes of lanthanides and americium by a monofunctional solvating ligand (tri-n-octylphosphine oxide, TOPO). Stability constants for successive nitrato complexes (M(NO3)x(3-x)(aq) where M is Eu(3+), Am(3+), or Cm(3+)) were determined to assist in the calculation of the extraction constant, K(ex), for the metal ions under study. Enthalpies of extraction (ΔH(extr)) for the lanthanide series (excluding Pm(3+)) and Am(3+) by TOPO have been measured using isothermal titration calorimetry. The observed ΔH(extr) were found to be constant at ~29 kJ mol(-1) across the series from La(3+) to Er(3+), with a slight decrease observed from Tm(3+) to Lu(3+). These heats were found to be consistent with enthalpies determined using van't Hoff analysis of temperature dependent extraction studies. A complete set of thermodynamic parameters (ΔG, ΔH, ΔS) was calculated for Eu(NO3)3, Am(NO3)3, and Cm(NO3)3 extraction by TOPO and Am(3+) and Cm(3+) extraction by bis(2-ethylhexyl) phosphoric acid (HDEHP). A discussion comparing the energetics of these systems is offered. The measured biphasic extraction heats for the transplutonium elements, ΔH(extr), presented in these studies are the first ever direct measurements offered using two-phase calorimetric techniques. PMID:25315891

  15. Phosphorus-containing fluorinated organics: polyfluoroalkyl phosphoric acid diesters (diPAPs), perfluorophosphonates (PFPAs), and perfluorophosphinates (PFPIAs) in residential indoor dust.

    PubMed

    De Silva, Amila O; Allard, Cody N; Spencer, Christine; Webster, Glenys M; Shoeib, Mahiba

    2012-11-20

    Indoor dust is thought to be a source of human exposure to perfluorocarboxylates (PFCAs) and perfluorosulfonates (PFSAs), but exposures to emerging organofluorine compounds, including precursors to PFCAs and PFSAs via indoor dust, remain unknown. We report an analytical method for measuring several groups of emerging phosphorus-containing fluorinated compounds, including polyfluoroalkyl phosphoric acid diesters (diPAP), perfluorophosphonates (PFPA), and perfluorophosphinates (PFPIA), as well as perfluoroethylcyclohexane sulfonate (PFECHS) in indoor dust. This method was used to analyze diPAP, PFPA, and PFPIA levels in 102 residential dust samples collected in 2007-2008 from Vancouver, Canada. The results indicated a predominant and ubiquitous presence of diPAPs (frequency of detection 100%, mean and median ΣdiPAPs 7637 and 2215 ng/g). Previously measured median concentrations of perfluorooctane sulfonate (PFOS), perfluorooctanoate (PFOA), and fluorotelomer alcohols (FTOHs) in the same samples were 14-74 times lower than ΣdiPAP levels, i.e. 71 ng/g PFOS, 30 ng/g PFOA, and 152 ng/g ΣFTOHs. PFPAs and PFPIAs were detected in 62% and 85% of samples, respectively, at concentrations nearly 3 orders of magnitude lower than diPAPs (median 2.3 ng/g ΣPFPAs and 2.3 ng/g ΣPFPIAs). PFECHS was detected in only 8% of dust samples. To the best of our knowledge, this is the first report of these compounds in indoor dust. In this study, diPAP concentrations represented 98% ± 7% of the total measured analytes in the dust samples. Detection of diPAPs at such high concentrations in indoor dust may represent an important and as-yet unrecognized indirect source of PFCA exposure in humans, given the identified biotransformation pathways. Identifying the sources of diPAPs to the indoor environment is a priority for future research to improve air quality in households.

  16. Lanthanide ion exchange properties of a coordination polymer consisting of di(2-ethylhexyl) phosphoric acid and trivalent metal ions (Ce3+, Fe3+, or Al3+).

    PubMed

    Ooi, Kenta; Tasaki-Handa, Yuiko; Abe, Yukie; Wakisaka, Akihiko

    2014-03-28

    Three kinds of coordination polymers ([M(dehp)3], M = Ce, Fe, or Al) were prepared by mixing the sodium form (Na(dehp)) of di(2-ethylhexyl) phosphoric acid and MCl3 in an ethanol-water binary mixture. They have monoclinic crystalline structure with similar lattice parameters. The lanthanide ion (Ln(3+) = La(3+), Sm(3+), Dy(3+), or Yb(3+)) exchange properties were studied in a 20 : 80 vol% ethanol-water binary mixture containing 2 mM Ln(NO3)3 at room temperature. The rate of Ln(3+) adsorption is relatively slow; it requires over 3 weeks to reach equilibrium. [M(dehp)3] has different Ln(3+) affinities depending on the kind of central metal ions: the affinity order at 3 week adsorption is Yb(3+) < La(3+) < Dy(3+) < Sm(3+) for [Ce(dehp)3], La(3+) < Sm(3+) < Dy(3+) < Yb(3+) for [Fe(dehp)3], and La(3+) < Sm(3+), Dy(3+), Yb(3+) for [Al(dehp)3]. The difference in affinity order can be explained by two factors: the coordination preference and steric strain caused by the polymeric structure. The chemical and structural analyses suggested that the Ln(3+) adsorption progresses first by the central M(3+)/Ln(3+) exchange, followed by a morphological change to a rod-like or fibrous form by a solid phase reaction. In the case of [Fe(dehp)3], the eluted Fe(3+) may be hydrolyzed and precipitated as amorphous iron hydroxide.

  17. Characterization and application of expanded graphite modified with phosphoric acid and glucose for the removal of Ni(II) from aqueous solution

    NASA Astrophysics Data System (ADS)

    Jiang, Li; Zhang, Jian; Xu, Xiaoli; Zhang, Jie; Liu, Hai; Guo, Zizhang; Kang, Yan; Li, Yiran; Xu, Jingtao

    2015-12-01

    Three kinds of modified expanded graphite (EG), impregnated with phosphoric acid (H3PO4) (P-EG), impregnated with glucose (G-EG), and impregnated with H3PO4 and glucose (G-P-EG), were prepared under a low temperature (150 °C). The adsorption capacity of G-P-EG (Qm = 7.016 mg/g) is much higher than original expanded graphite (EG Qm = 0.423 mg/g) and other two kinds of modified expanded graphite (P-EG Qm = 0.770 mg/g; G-EG Qm = 0.507 mg/g). The physicochemical properties of EG and G-P-EG were characterized by N2 adsorption/desorption, Boehm's titration and X-ray photoelectron spectroscopy (XPS). EG exhibited higher values of BET surface area (11.357 m2/g) and total pore volume (0.0303 cm3/g) than that of G-P-EG (4.808 m3/g and 0.0109 cm3/g). However, the results of Bohm's titration and XPS showed that G-P-EG contained more surface oxygen-containing functional groups. The Ni(II) adsorption equilibrium data agreed well with the Langmuir model. And the experimental data of EG and G-P-EG fitted better by pseudo-second order model. Based on the results of batch adsorption experiments and XPS analysis, there were several possible mechanisms for Ni(II) adsorption on the G-P-EG, including chemical adsorption, cation exchange, electrostatic attraction and surface complication.

  18. Lyoluminescence, thermoluminescence and mechanoluminescence studies in γ-ray irradiated Dy3+ activated potassium chloride phosphor for accidental radiation dosimetry.

    PubMed

    Bhujbal, P M; Dhoble, S J

    2012-01-01

    The lyoluminescence (LL), thermoluminescence (TL) and mechanoluminescence (ML) of γ-ray-irradiated coloured powder of KCl:Dy (0.05-0.5 mol%) phosphors are reported in this paper. To understand the mechanism of LL and ML, the LL and ML spectra are compared with TL studies. The variation of intensity of respective luminescence with different γ-ray doses and with different concentrations of Dy3+ ion doped in KCl is found to be similar in nature. The intensities differ from each other, but their nature is found to be similar with γ-ray exposures. The ML glow peak intensity is linear up to high 1 kGy exposure as compared to LL (up to 0.5 kGy) and TL (up to 0.75 kGy) techniques. Therefore, according to our results, the recommendation is that KCl:Dy (0.1 mol%) phosphor prepared by wet chemical technique is useful for high-dose measurements using the ML technique for accidental radiation dosimetry.

  19. A new facile route for synthesizing of graphene oxide using mixture of sulfuric-nitric-phosphoric acids as intercalating agent

    NASA Astrophysics Data System (ADS)

    Panwar, Vinay; Chattree, Ananya; Pal, Kaushik

    2015-09-01

    In this work, graphene oxide (GO) has been prepared through three different processes namely, eco-friendly Hummers method, modification in improved Hummers method and a new approach. This new approach has been designed by changing some processing parameters and intercalating agent for significant reduction in processing time and to improve the quantity of GO in comparison to the other two methods. This has been achieved through better oxidization of graphite using nitric-sulfuric acid (HNO3-H2SO4) as intercalating agent. X-ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), Energy-dispersive X-ray spectroscopy (EDX), Raman spectroscopy, Atomic Force Microscopy (AFM), X-ray photoelectron spectroscopy (XPS), UV-visible spectroscopy, and Thermogravimetric analysis (TGA) are used to characterize the GO prepared through different processes. These characterizations have confirmed an improved exfoliation of graphite, using addition of HNO3 in intercalating agent, in a short processing time and bring on higher yield of GO via this new process.

  20. Kimzeyite garnet phosphors

    DOEpatents

    Lyons, Robert Joseph

    2013-05-14

    A phosphor of formula I is included in a phosphor composition in a lighting apparatus capable of emitting white light, Ca.sub.3-x-zSr.sub.xCe.sub.zM.sup.1.sub.2M.sup.2AlSiO.sub.12 (I) wherein M.sup.1 is Hf, Zr, or a combination thereof; M.sup.2 is Al, or a combination of Al and Ga; z<3-x; and 0.2>x.gtoreq.0. The lighting apparatus includes a semiconductor light source in addition to the phosphor composition.

  1. Fabrication of cerium active terbium aluminum garnet (TAG:Ce) phosphor powder via the solid-state reaction method

    SciTech Connect

    Tsai, M.-S. Liu, G.-M.; Chung, S.-L.

    2008-05-06

    A modified solid-state reaction method for the formation of terbium aluminum garnet (TAG:Ce) powder was studied. The starting materials, which included terbium oxide (Tb{sub 4}O{sub 7}), boehmite and cerium chloride (CeCl{sub 3}.7H{sub 2}O), were pre-aged at pH 3. This pre-aging process helps to form the core-shell structure, which leads to the formation of TAG:Ce phosphor powder via a solid-state reaction more easily. The emission intensity at 551 nm of the product pre-aged at pH 3 is higher than that formed without pre-aging.

  2. Synthesis, characterization and TL response of Ce{sup 3+} activated BaMgAl{sub 10}O{sub 17} phosphor

    SciTech Connect

    Selot, Anupam; Aynyas, Mahendra; Tiwari, Manoj; Dev, Kapil

    2015-06-24

    Phosphor material BaMgAl{sub 10}O{sub 17} with varying concentration of rare earth Ce{sup 3+} synthesis by combustion method at 500°C. The synthesized phosphor material characterized for their crystallinity and nature by XRD measurements. The thermoluminescecne response of phosphor exhibit TL spectra at 204°c and detailed analysis of kinetic parameter by de convoluted curve. These results show that concentration quenching occur at 5mol% of Ce dopant. The results suggest the possibility of utilizing as a phosphor may be in UV dosimeter and solid state lighting.

  3. Building biologically active nucleic acid nanocomplexes.

    PubMed

    Smith, C I Edvard; Lundin, Karin E; Simonson, Oscar E; Moreno, Pedro M D; Svahn, Mathias G; Wenska, Malgorzata; Strömberg, Roger

    2008-01-01

    The Bioplex technology allows the hybridization of functional entities to various forms of nucleic acids by the use of synthetic nucleic acid analogs. Such supramolecular assemblies can be made in a predetermined fashion and can confer new properties. The Zorro technology is based on a novel construct generated to simultaneously bind to both DNA strands. Such compounds may have gene silencing activity.

  4. High temperature thermometric phosphors

    DOEpatents

    Allison, Stephen W.; Cates, Michael R.; Boatner, Lynn A.; Gillies, George T.

    1999-03-23

    A high temperature phosphor consists essentially of a material having the general formula LuPO.sub.4 :Dy.sub.(x),Eu.sub.y) wherein: 0.1 wt %.ltoreq.x.ltoreq.20 wt % and 0.1 wt %.ltoreq.y.ltoreq.20 wt %. The high temperature phosphor is in contact with an article whose temperature is to be determined. The article having the phosphor in contact with it is placed in the environment for which the temperature of the article is to be determined. The phosphor is excited by a laser causing the phosphor to fluoresce. The emission from the phosphor is optically focused into a beam-splitting mirror which separates the emission into two separate emissions, the emission caused by the dysprosium dopant and the emission caused by the europium dopent. The separated emissions are optically filtered and the intensities of the emission are detected and measured. The ratio of the intensity of each emission is determined and the temperature of the article is calculated from the ratio of the intensities of the separate emissions.

  5. High temperature thermometric phosphors

    DOEpatents

    Allison, S.W.; Cates, M.R.; Boatner, L.A.; Gillies, G.T.

    1999-03-23

    A high temperature phosphor consists essentially of a material having the general formula LuPO{sub 4}:Dy{sub x},Eu{sub y} wherein: 0.1 wt % {<=} x {<=} 20 wt % and 0.1 wt % {<=} y {<=} 20 wt %. The high temperature phosphor is in contact with an article whose temperature is to be determined. The article having the phosphor in contact with it is placed in the environment for which the temperature of the article is to be determined. The phosphor is excited by a laser causing the phosphor to fluoresce. The emission from the phosphor is optically focused into a beam-splitting mirror which separates the emission into two separate emissions, the emission caused by the dysprosium dopant and the emission caused by the europium dopant. The separated emissions are optically filtered and the intensities of the emission are detected and measured. The ratio of the intensity of each emission is determined and the temperature of the article is calculated from the ratio of the intensities of the separate emissions. 2 figs.

  6. Phosphors for LED lamps

    DOEpatents

    Murphy, James Edward; Manepalli, Satya Kishore; Kumar, Prasanth Nammalwar

    2013-08-13

    A phosphor, a phosphor blend including the phosphor, a phosphor prepared by a process, and a lighting apparatus including the phosphor blend are disclosed. The phosphor has the formula (Ca.sub.1-p-qCe.sub.pK.sub.q).sub.xSc.sub.y(Si.sub.1-rGa.sub.r).sub.zO.su- b.12+.delta. or derived from a process followed using disclosed amounts of reactants. In the formula, (0

  7. Zymographic detection of cinnamic acid decarboxylase activity.

    PubMed

    Prim, Núria; Pastor, F I Javier; Diaz, Pilar

    2002-11-01

    The manuscript includes a concise description of a new, fast and simple method for detection of cinnamic acid decarboxylase activity. The method is based on a color shift caused a by pH change and may be an excellent procedure for large screenings of samples from natural sources, as it involves no complex sample processing or purification. The method developed can be used in preliminary approaches to biotransformation processes involving detection of hydroxycinnamic acid decarboxylase activity.

  8. Preparation and Characterization of Chromium(III)-Activated Yttrium Aluminum Borate: A New Thermographic Phosphor for Optical Sensing and Imaging at Ambient Temperatures

    PubMed Central

    2010-01-01

    A new thermographic phosphor based on chromium(III)-doped yttrium aluminum borate (YAB) is obtained as single crystals by high temperature flux growth and as a microcrystalline powder via solution combustion synthesis. The phosphor is excitable both in the blue (λmax 422 nm) and in the red part of the spectrum (λmax 600 nm) and shows bright NIR emission. The brightness of the phosphor is comparable to that of a well-known lamp phosphor Mn(IV)-doped magnesium fluorogermanate. At ambient temperatures, the Cr(III)-doped YAB shows high temperature dependence of the luminescence decay time, which approaches 1% per deg. The material shows no decrease in luminescence intensity at higher temperatures. The new phosphor is particularly promising for applications in temperature-compensated optical chemosensors (including those based on NIR-emitting indicators) and in pressure-sensitive paints. PMID:20473368

  9. MULTI-PHOTON PHOSPHOR FEASIBILITY RESEARCH

    SciTech Connect

    R. Graham; W. Chow

    2003-05-01

    Development of multi-photon phosphor materials for discharge lamps represents a goal that would achieve up to a doubling of discharge (fluorescent) lamp efficacy. This report reviews the existing literature on multi-photon phosphors, identifies obstacles in developing such phosphors, and recommends directions for future research to address these obstacles. To critically examine issues involved in developing a multi-photon phosphor, the project brought together a team of experts from universities, national laboratories, and an industrial lamp manufacturer. Results and findings are organized into three categories: (1) Multi-Photon Systems and Processes, (2) Chemistry and Materials Issues, and (3) Concepts and Models. Multi-Photon Systems and Processes: This category focuses on how to use our current understanding of multi-photon phosphor systems to design new phosphor systems for application in fluorescent lamps. The quickest way to develop multi-photon lamp phosphors lies in finding sensitizer ions for Gd{sup 3+} and identifying activator ions to red shift the blue emission from Pr{sup 3+} due to the {sup 1}S{sub 0} {yields} {sup 1}I{sub 6} transition associated with the first cascading step. Success in either of these developments would lead to more efficient fluorescent lamps. Chemistry and Materials Issues: The most promising multi-photon phosphors are found in fluoride hosts. However, stability of fluorides in environments typically found in fluorescent lamps needs to be greatly improved. Experimental investigation of fluorides in actual lamp environments needs to be undertaken while working on oxide and oxyfluoride alternative systems for backup. Concepts and Models: Successful design of a multi-photon phosphor system based on cascading transitions of Gd{sup 3+} and Pr{sup 3+} depends critically on how the former can be sensitized and the latter can sensitize an activator ion. Methods to predict energy level diagrams and Judd-Ofelt parameters of multi

  10. Photoluminescence, energy transfer and tunable color of Ce(3+), Tb(3+) and Eu(2+) activated oxynitride phosphors with high brightness.

    PubMed

    Lü, Wei; Huo, Jiansheng; Feng, Yang; Zhao, Shuang; You, Hongpeng

    2016-06-21

    New tuneable light-emitting Ca3Al8Si4O17N4:Ce(3+)/Tb(3+)/Eu(2+) oxynitride phosphors with high brightness have been prepared. When doped with trivalent cerium or divalent europium they present blue luminescence under UV excitation. The energy transfer from Ce(3+) to Tb(3+) and Ce(3+) to Eu(2+) ions is deduced from the spectral overlap between Ce(3+) emission and Tb(3+)/Eu(2+) excitation spectra. The energy-transfer efficiencies and corresponding mechanisms are discussed in detail, and the mechanisms of energy transfer from the Ce(3+) to Tb(3+) and Ce(3+) to Eu(2+) ions are demonstrated to be a dipole-quadrupole and dipole-dipole mechanism, respectively, by the Inokuti-Hirayama model. The International Commission on Illumination value of color tuneable emission as well as luminescence quantum yield (23.8-80.6%) can be tuned by controlling the content of Ce(3+), Tb(3+) and Eu(2+). All results suggest that they are suitable for UV light-emitting diode excitation. PMID:27226201

  11. Color stable manganese-doped phosphors

    DOEpatents

    Lyons, Robert Joseph; Setlur, Anant Achyut; Deshpande, Anirundha Rajendra; Grigorov, Ljudmil Slavchev

    2014-04-29

    A lighting apparatus capable of emitting white light includes a semiconductor light source; and a phosphor material radiationally coupled to the light source. The phosphor material includes a color-stable Mn.sup.+4 doped phosphor prepared by a process including providing a phosphor of formula I; A.sub.x[MF.sub.y]:Mn.sup.+4 I and contacting the phosphor in particulate form with a saturated solution of a composition of formula II in aqueous hydrofluoric acid; A.sub.x[MF.sub.y]; II wherein A is Li, Na, K, Rb, Cs, NR.sub.4 or a combination thereof; M is Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Y, La, Nb, Ta, Bi, Gd, or a combination thereof; R is H, lower alkyl, or a combination thereof; x is the absolute value of the charge of the [MF.sub.y] ion; and y is 5, 6 or 7. In particular embodiments, M is Si, Ge, Sn, Ti, Zr, or a combination thereof.

  12. Color stable manganese-doped phosphors

    DOEpatents

    Lyons, Robert Joseph; Setlur, Anant Achyut; Deshpande, Anirudha Rajendra; Grigorov, Ljudmil Slavchev

    2012-08-28

    A process for preparing color stable Mn.sup.+4 doped phosphors includes providing a phosphor of formula I; A.sub.x[MF.sub.y]:Mn.sup.+4 I and contacting the phosphor in particulate form with a saturated solution of a composition of formula II in aqueous hydrofluoric acid; A.sub.x[MF.sub.y]; II wherein A is Li, Na, K, Rb, Cs, NR.sub.4 or a combination thereof; M is Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Y, La, Nb, Ta, Bi, Gd, or a combination thereof; R is H, lower alkyl, or a combination thereof; x is the absolute value of the charge of the [MF.sub.y] ion; and y is 5, 6 or 7. In particular embodiments, M is Si, Ge, Sn, Ti, Zr, or a combination thereof. A lighting apparatus capable of emitting white light includes a semiconductor light source; and a phosphor composition radiationally coupled to the light source, and which includes a color stable Mn.sup.+4 doped phosphor.

  13. Nickel cobalt phosphorous low stress electroplating

    NASA Technical Reports Server (NTRS)

    Engelhaupt, Darell E. (Inventor); Ramsey, Brian D. (Inventor)

    2002-01-01

    An electrolytic plating process is provided for electrodepositing a nickel or nickel cobalt alloy which contains at least about 2% to 25% by atomic volume of phosphorous. The process solutions contains nickel and optionally cobalt sulfate, hypophosphorous acid or a salt thereof, boric acid or a salt thereof, a monodentate organic acid or a salt thereof, and a multidentate organic acid or a salt thereof. The pH of the plating bath is from about 3.0 to about 4.5. An electroplating process is also provided which includes electroplating from the bath a nickel or nickel cobalt phosphorous alloy. This process can achieve a deposit with high microyield of at least about 84 kg/mm.sup.2 (120 ksi) and a density lower than pure nickel of about 8.0 gm/cc. This process can be used to plate a deposit of essentially zero stress at plating temperatures from ambient to 70.degree. C.

  14. Phosphorus, phosphorous, and phosphate.

    PubMed

    Iheagwara, O Susan; Ing, Todd S; Kjellstrand, Carl M; Lew, Susie Q

    2013-10-01

    This article distinguishes the terms "phosphorus, phosphorous, and phosphate" which are frequently used interchangeably. We point out the difference between phosphorus and phosphate, with an emphasis on the unit of measure. Expressing a value without the proper name or unit of measure may lead to misunderstanding and erroneous conclusions. We indicate why phosphate must be expressed as milligrams per deciliter or millimoles per liter and not as milliequivalents per liter. Therefore, we elucidate the distinction among the terms "phosphorus, phosphorous, and phosphate" and the importance of saying precisely what one really means.

  15. A high sensitive phosphor for dosimetric applications

    SciTech Connect

    Kore, Bhushan P. Dhoble, S. J.; Dhoble, N. S.; Lochab, S. P.

    2015-06-24

    In this study a novel TL phosphor CaMg{sub 3}(SO{sub 4}){sub 4}:Dy{sup 3+} was prepared by acid distillation method. The TL response of this phosphor towards γ-rays and carbon ion beam was tested. Good dosimetric glow curve was observed which is stable against both the type of radiations. The CaMg{sub 3}(SO{sub 4}){sub 4}:Dy{sup 3+} phosphor doped with 0.2 mol% of Dy{sup 3+}, irradiated with γ-ray shows nearly equal sensitivity to that of commercially available CaSO{sub 4}:Dy TLD phosphor whereas 3.5 times more sensitivity than CaSO{sub 4}:Dy, when irradiated with carbon ion beam. The change in glow peak intensities and glow peak temperature with variation in irradiation species and energy of ion beam is discussed here. The effect of these on trapping parameters is also illustrated.

  16. Surface modification with phosphoric acid of SiO2/Nb2O5 prepared by the sol-gel method: structural-textural and acid sites studies and an ion exchange model.

    PubMed

    Francisco, M S P; Cardoso, W S; Gushikem, Y; Landers, R; Kholin, Y V

    2004-09-28

    In this work, the structural and textural properties of the SiO2/Nb2O5 system prepared by the sol-gel method and then modified by phosphoric acid were studied. The different materials were prepared, with three different mol % Nb2O5 (2.5, 5.0, and 7.5 mol %), and calcined in the temperature range of 423-1273 K. BET specific surface area determinations, scanning electron microscopy connected to a X-ray emission analyzer, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy (XPS) were used for the investigation. For the lowest temperature of calcination (423 K), the mesopores and micropores of the modified material were blocked, resulting in a decrease of the specific surface area compared to the SBET values obtained for the SiNb matrix. Under intermediate temperatures of calcination (423-873 K), the modified material acquired textural stability. By XPS analysis, the presence of the dihydrogenphosphate species was identified, the P/Nb atomic ratios being independent of the thermal treatment. 31P magic angle spinning NMR confirmed the XPS data and also showed that the chemical shift of the (H2PO4)- ions strongly depended on the crystallization degree of the Nb2O5. Structural thermal stability was also shown by the presence of Brønsted acid sites in the modified material calcined at high temperature (1273 K). The thermal stability is directly associated with obtainment of the same value for K+ exchange capacity (0.74 mmol g(-1), average value) for the modified materials calcined at 423 and 1273 K. The chemical analyses of phosphorus for the modified materials were made by using the inductively coupled plasma. The value was 0.36 mmol g(-1), corroborating the presence of (H2PO4)- ions. The ion exchange isotherms presented an S-shaped form characteristic of energetically heterogeneous ion exchangers, permitting application of a model of fixed polydentate centers, in which ion exchange took place. PMID:15379496

  17. Enhancement of photoluminescence in Eu3+ co-activated Ca2MgSi2O7:Dy3+ phosphors for solid state lighting application

    NASA Astrophysics Data System (ADS)

    Mondal, Kanchan; Manam, J.

    2016-12-01

    A series of Ca2MgSi2O7:Dy3+, Ca2MgSi2O7:Eu3+and Ca2MgSi2O7:Dy3+, Eu3+phosphors were synthesized by conventional solid state reaction method. The X-ray diffraction (XRD) patterns were recorded to confirm the phase purity of Ca2MgSi2O7 phosphors. The XRD results showed that the prepared phosphors have single-phase tetragonal structure and incorporation of dopants has no effect on the crystal structure of phosphors. The surface morphological studies were performed using field emission scanning electronic spectroscopy (FESEM). Photoluminescence (PL) properties were systematically investigated in detail. With increasing, Dy3+ concentration the PL intensity first increases, reaches the maximum and then it was decreased. A Similar trend was shown in Ca2MgSi2O7:Eu3+ phosphors. The PL emission intensity was increased at the transitions 5D0 → 7F1 and 5D0 → 7F2 with increasing Eu3+ concentration while decreased the intensity at the transitions 4F9/2 → 6H15/2 and 4F9/2 → 6H13/2. The calculated band gap values of the sample were found to be 4.29, 4.38, 4.11 and 4.23 eV.

  18. Phosphorous trapped within buckminsterfullerene

    NASA Astrophysics Data System (ADS)

    Larsson, J. A.; Greer, J. C.; Harneit, W.; Weidinger, A.

    2002-05-01

    Under normal circumstances, when covalent molecules form, electrons are exchanged between atoms to form bonds. However, experiment and theoretical computations reveal exactly the opposite effect for the formation of group V elements nitrogen and phosphorous encapsulated within a buckminsterfullerene molecule. The C60 carbon cage remains intact upon encapsulation of the atom, whereas the electronic charge cloud of the N or P atom contracts. We have studied the chemical, spin, and thermodynamic properties of endohedral phosphorous (P@C60) and have compared our results with earlier findings for N@C60. From a combined experimental and theoretical vantage, we are able to elucidate a model for the interaction between the trapped group V atom and the fullerene cage. A picture emerges for the electronic structure of these complexes, whereby an atom is trapped within a fullerene, and interacts weakly with the molecular orbitals of the C60 cage.

  19. Green emitting phosphors and blends thereof

    DOEpatents

    Setlur, Anant Achyut; Siclovan, Oltea Puica; Nammalwar, Prasanth Kumar; Sathyanarayan, Ramesh Rao; Porob, Digamber G.; Chandran, Ramachandran Gopi; Heward, William Jordan; Radkov, Emil Vergilov; Briel, Linda Jane Valyou

    2010-12-28

    Phosphor compositions, blends thereof and light emitting devices including white light emitting LED based devices, and backlights, based on such phosphor compositions. The devices include a light source and a phosphor material as described. Also disclosed are phosphor blends including such a phosphor and devices made therefrom.

  20. Intravascular imaging with a storage phosphor detector

    NASA Astrophysics Data System (ADS)

    Shikhaliev, Polad M.; Petrek, Peter; Matthews, Kenneth L., II; Fritz, Shannon G.; Bujenovic, L. Steven; Xu, Tong

    2010-05-01

    The aim of this study is to develop and test an intravascular positron imaging system based on a storage phosphor detector for imaging and detecting vulnerable plaques of human coronary arteries. The radiotracer F18-FDG accumulates in vulnerable plaques with inflammation of the overlying cap. The vulnerable plaques can, therefore, be imaged by recording positrons emitted from F18-FDG with a detector inserted into the artery. A prototype intravascular detector was constructed based on storage phosphor. The detector uses a flexible storage phosphor tube with 55 mm length, 2 mm diameter and 0.28 mm wall thickness. The intravascular detector is guided into the vessel using x-ray fluoroscopy and the accumulated x-ray signal must be erased prior to positron imaging. For this purpose, a light diffuser, 0.9 mm in diameter and 55 mm in length, was inserted into the detector tube. The light diffuser was connected to a laser source through a 2 m long optical fiber. The diffuser redirected the 0.38 W laser light to the inner surface of the phosphor detector to erase it. A heart phantom with 300 cm3 volume and three coronary arteries with 3.2 mm diameter and with several plaques was constructed. FDG solution with 0.5 µCi cm-3 activity concentration was filled in the heart and coronary arteries. The detector was inserted in a coronary artery and the signal from the plaques and surrounding background activity was recorded for 2 min. Then the phosphor detector was extracted and read out using a storage phosphor reader. The light diffuser erased the signal resulting from fluoroscopic exposure to level below that encountered during positron imaging. Vulnerable plaques with area activities higher than 1.2 nCi mm-2 were visualized by the detector. This activity is a factor of 10-20 lower than that expected in human vulnerable plaques. The detector was able to image the internal surface of the coronary vessels with 50 mm length and 360° circumference. Spatial resolution was 0

  1. Application of single ion activity coefficients to determine solvent extraction mechanism for components of high level nuclear waste

    SciTech Connect

    Nunez, L.; Vandegrift, G.F.

    1995-12-31

    The TRUEX solvent extraction process is being developed to remove and concentrate transuranic (TRU) elements from high-level and TRU radioactive wastes currently stored at US Department of Energy sites. Phosphoric acid is one of the chemical species of concern at the Hanford site where bismuth phosphate was used to recover plutonium. The mechanism of phosphoric acid extraction with TRUEX-NPH solvent at 25{degrees}C was determined by phosphoric acid distribution ratios, which were measured by using phosphoric acid radiotracer and a variety of aqueous phases containing different concentrations of nitric acid and nitrate ions. A model was developed for predicting phosphoric acid distribution ratios as a function of the thermodynamic activities of nitrate ion and hydrogen ion. The Generic TRUEX Model (GTM) was used to calculate these activities based on the Bromley method. The derived model supports CMPO and TBP extraction of a phosphoric acid-nitric acid complex and a CMPO-phosphoric acid complex in TRUEX-NPH solvent.

  2. Long-persistence blue phosphors

    NASA Technical Reports Server (NTRS)

    Yen, William M. (Inventor); Jia, Weiyi (Inventor); Lu, Lizhu (Inventor); Yuan, Huabiao (Inventor)

    2000-01-01

    This invention relates to phosphors including long-persistence blue phosphors. Phosphors of the invention are represented by the general formula: MO . mAl.sub.2 O.sub.3 :Eu.sup.2+,R.sup.3+ wherein m is a number ranging from about 1.6 to about 2.2, M is Sr or a combination of Sr with Ca and Ba or both, R.sup.3+ is a trivalent metal ion or trivalent Bi or a mixture of these trivalent ions, Eu.sup.2+ is present at a level up to about 5 mol % of M, and R.sup.3+ is present at a level up to about 5 mol % of M. Phosphors of this invention include powders, ceramics, single crystals and single crystal fibers. A method of manufacturing improved phosphors and a method of manufacturing single crystal phosphors are also provided.

  3. Development of a Blue Emitting Calcium-Aluminate Phosphor

    PubMed Central

    Kim, Doory; Kim, Han-Eol; Kim, Chang-Hong

    2016-01-01

    We report methodological advances that enhance the phosphorescence efficiency of a blue-emitting calcium aluminate phosphor (CaAl2O4: Eu2+, Nd3+). The investigation of long-persistence blue-emitting phosphors is highly desirable due to their promising applications, such as white LEDs; however, the development of highly efficient blue-emitting phosphors is still challenging. Here, we have quantitatively characterized the phosphorescence properties of the blue-emitting phosphor CaAl2O4:Eu2+, Nd3+ with various compositions and directly related these properties to the quality of its luminescence. We optimized the composition of the activator Eu2+ and the co-activator Nd3+, the doping conditions with alkaline earth metals, alkali metals, and Si to create crystallographic distortions and, finally, the flux conditions to find the best parameters for bright and persistent blue-emitting phosphors. Our research has identified several doping compositions with good to excellent performance, with which we have demonstrated bright and persistent phosphors with afterglow characteristics superior to those of conventional phosphors. PMID:27648560

  4. Development of a Blue Emitting Calcium-Aluminate Phosphor.

    PubMed

    Kim, Doory; Kim, Han-Eol; Kim, Chang-Hong

    2016-01-01

    We report methodological advances that enhance the phosphorescence efficiency of a blue-emitting calcium aluminate phosphor (CaAl2O4: Eu2+, Nd3+). The investigation of long-persistence blue-emitting phosphors is highly desirable due to their promising applications, such as white LEDs; however, the development of highly efficient blue-emitting phosphors is still challenging. Here, we have quantitatively characterized the phosphorescence properties of the blue-emitting phosphor CaAl2O4:Eu2+, Nd3+ with various compositions and directly related these properties to the quality of its luminescence. We optimized the composition of the activator Eu2+ and the co-activator Nd3+, the doping conditions with alkaline earth metals, alkali metals, and Si to create crystallographic distortions and, finally, the flux conditions to find the best parameters for bright and persistent blue-emitting phosphors. Our research has identified several doping compositions with good to excellent performance, with which we have demonstrated bright and persistent phosphors with afterglow characteristics superior to those of conventional phosphors. PMID:27648560

  5. Blue light emitting thiogallate phosphor

    DOEpatents

    Dye, Robert C.; Smith, David C.; King, Christopher N.; Tuenge, Richard T.

    1998-01-01

    A crystalline blue emitting thiogallate phosphor of the formula RGa.sub.2 S.sub.4 :Ce.sub.x where R is selected from the group consisting of calcium, strontium, barium and zinc, and x is from about 1 to 10 atomic percent, the phosphor characterized as having a crystalline microstructure on the size order of from about 100 .ANG. to about 10,000 .ANG. is provided together with a process of preparing a crystalline blue emitting thiogallate phosphor by depositing on a substrate by CVD and resultant thin film electroluminescent devices including a layer of such deposited phosphor on an ordinary glass substrate.

  6. Structure, Crystallographic Sites, and Tunable Luminescence Properties of Eu(2+) and Ce(3+)/Li(+)-Activated Ca1.65Sr0.35SiO4 Phosphors.

    PubMed

    Xia, Zhiguo; Miao, Shihai; Chen, Mingyue; Molokeev, Maxim S; Liu, Quanlin

    2015-08-17

    Eu(2+) and Ce(3+)/Li(+) singly doped and Eu(2+)/Ce(3+)/Li(+)-codoped Ca1.65Sr0.35SiO4 phosphors have been synthesized by a solid-state reaction method. The crystal structure was determined by Rietveld refinement to verify the formation of the αL′-Ca2SiO4 phase with the Sr addition into Ca2SiO4, and the preferred crystallographic positions of the Eu(2+) and Ce(3+)/Li(+) ions in Ca1.65Sr0.35SiO4 were analyzed based on a comparison of the unit-cell volumes and the designed chemical compositions of undoped isostructural compounds Ca(2–x)Sr(x)SiO4 (x = 0.25, 0.35, 0.45, 0.55 and 0.65). Ce(3+)/Li(+) singly activated Ca1.65Sr0.35SiO4 phosphors exhibit strong absorption in the range of 250–450 nm and a blue emission peak centered at about 465 nm. When Eu(2+) ions are codoped, the emission colors of Ca1.65Sr0.35SiO4:Ce(3+)/Li(+),Eu(2+) phosphors under the irradiation of 365 nm can be finely tuned from blue to green through the energy transfer from Ce(3+) to Eu(2+). The involved energy-transfer process between Ce(3+) and Eu(2+) and the corresponding mechanism are discussed in detail. The reported Ca1.65Sr0.35SiO4:Ce(3+)/Li(+),Eu(2+) phosphor might be a candidate for color-tunable blue-green components in the fabrication of near-ultraviolet-pumped white-light-emitting diodes (WLEDs). PMID:26062769

  7. Review of HxPyOz-Catalyzed H + OH Recombination in Scramjet Nozzle Expansions; and Possible Phosphoric Acid Enhancement of Scramjet Flameholding, from Extinction of H3PO4 + H2 - Air Counterflow Diffusion Flames

    NASA Technical Reports Server (NTRS)

    Pellett, Gerald

    2005-01-01

    Recent detailed articles by Twarowski indicate that small quantities of phosphorus oxides and acids in the fuel-rich combustion products of H2 + phosphine (PH3) + air should significantly catalyze H, OH and O recombination kinetics during high-speed nozzle expansions -- to reform H2O, release heat, and approach equilibrium more rapidly and closely than uncatalyzed kinetics. This paper is an initial feasibility study to determine (a) if addition of phosphoric acid vapor (H3PO4) to a H2 fuel jet -- which is much safer than using PH3 -- will allow combustion in a high-speed scramjet engine test without adverse effects on localized flameholding, and (b) if phosphorus-containing exhaust emissions are environmentally acceptable. A well-characterized axisymmetric straight-tube opposed jet burner (OJB) tool is used to evaluate H3PO4 addition effects on the air velocity extinction limit (flame strength) of a H2 versus air counterflow diffusion flame. Addition of nitric oxide (NO), also believed to promote catalytic H-atom recombination, was evaluated for comparison. Two to five mass percent H3PO4 in the H2 jet increased flame strength 4.2%, whereas airside addition decreased it 1%. Adding 5% NO to the H2 caused a 2% decrease. Products of H-atom attack on H3PO4 produced an intense green chemiluminescence near the stagnation point. The resultant exothermic production of phosphorus oxides and acids, with accelerated H-atom recombination, released sufficient heat near the stagnation point to increase flame strength. In conclusion, the addition of H3PO4 vapor (or more reactive P sources) to hydrogen in scramjet engine tests may positively affect flameholding stability in the combustor and thrust production during supersonic expansion -- a possible dual benefit with system design / performance implications. Finally, a preliminary assessment of possible environmental effects indicates that scramjet exhaust emissions should consist of phosphoric acid aerosol, with gradual

  8. Photoinduced biochemical activity of fullerene carboxylic acid

    SciTech Connect

    Tokuyama, Hidetoshi; Yamago, Shigeru; Nakamura, Eiichi; Shiraki, Takashi; Sugiura, Yukio

    1993-08-25

    Here we report the preparation of a water-miscible fullerene carboxylic acid (2) and its biological activity-cytotoxicity and G-selective DNA cleaving ability. What is truly remarkable is that the biological activity of C{sub 60} was observed only under irradiation with visible light and not in the dark, suggesting that fullerenes may serve as useful photosensitive biochemical probes. We have found, for the first time, that even low-energy visible light is surfficient to induce biological activity in fullerene derivatives. Among the numerous implications of the present findings, the most exciting prospect includes the use of fullerene derivatives for photodynamic therapy. 18 refs., 2 figs., 1 tab.

  9. Phase transition and multicolor luminescence of Eu{sup 2+}/Mn{sup 2+}-activated Ca{sub 3}(PO{sub 4}){sub 2} phosphors

    SciTech Connect

    Li, Kai; Chen, Daqin; Xu, Ju; Zhang, Rui; Yu, Yunlong; Wang, Yuansheng

    2014-01-01

    Graphical abstract: We have synthesized Eu{sup 2+} doped and Eu{sup 2+}/Mn{sup 2+} co-doped Ca{sub 3}(PO{sub 4}){sub 2} phosphors. The emitting color varies from blue to green with increasing of Eu{sup 2+} content for the Eu{sup 2+}-doped phosphor, and the quantum yield of the 0.05Eu{sup 2+}: Ca{sub 2.95}(PO{sub 4}){sub 2} sample reaches 56.7%. Interestingly, Mn{sup 2+} co-doping into Eu{sup 2+}: Ca{sub 3}(PO{sub 4}){sub 2} leads to its phase transition from orthorhombic to rhombohedral, and subsequently generates tunable multi-color luminescence from green to red via Eu{sup 2+} → Mn{sup 2+} energy transfer. - Highlights: • A series of novel Eu{sup 2+}: Ca{sub 3}(PO{sub 4}){sub 2} phosphors were successfully synthesized. • Phase transition of Ca{sub 3}(PO{sub 4}){sub 2} from orthorhombic to rhombohedral occurred when Mn{sup 2+} ions were doped. • The phosphors exhibited tunable multi-color luminescence. • The quantum yield of 0.05Eu{sup 2+}: Ca{sub 2.95}(PO{sub 4}){sub 2} phosphor can reach 56.7%. • The analyses of phosphors were carried out by many measurements. - Abstract: Intense blue-green-emitting Eu{sup 2+}: Ca{sub 3}(PO{sub 4}){sub 2} and tunable multicolor-emitting Eu{sup 2+}/Mn{sup 2+}: Ca{sub 3}(PO{sub 4}){sub 2} phosphors are prepared via a solid-state reaction route. Eu{sup 2+}-doped orthorhombic Ca{sub 3}(PO{sub 4}){sub 2} phosphor exhibits a broad emission band in the wavelength range of 400–700 nm with a maximum quantum yield of 56.7%, and the emission peak red-shifts gradually from 479 to 520 nm with increase of Eu{sup 2+} doping content. Broad excitation spectrum (250–420 nm) of Eu{sup 2+}: Ca{sub 3}(PO{sub 4}){sub 2} matches well with the near-ultraviolet LED chip, indicating its potential applications as tri-color phosphors in white LEDs. Interestingly, Mn{sup 2+} co-doping into Eu{sup 2+}: Ca{sub 3}(PO{sub 4}){sub 2} leads to its phase transition from orthorhombic to rhombohedral, and subsequently generates tunable multi

  10. Chemical Vapor Deposition of Phosphorous- and Boron-Doped Graphene Using Phenyl-Containing Molecules.

    PubMed

    Mekan Ovezmyradov; Magedov, Igor V; Frolova, Liliya V; Chandler, Gary; Garcia, Jill; Bethke, Donald; Shaner, Eric A; Kalugin, Nikolai G

    2015-07-01

    Simultaneous chemical vapor deposition (CVD) of graphene and "in-situ" phosphorous or boron doping of graphene was accomplished using Triphenylphosphine (TPP) and 4-Methoxyphenylboronic acid (4-MPBA). The TPP and 4-MPBA molecules were sublimated and supplied along with CH4 molecules during graphene growth at atmospheric pressure. The grown graphene samples were characterized using Raman spectroscopy. Phosphorous and boron presence in phosphorous and boron doped graphene was confirmed with Auger electron spectroscopy. The possibility of obtaining phosphorous and boron doped graphene using solid-source molecule precursors via CVD can lead to an easy and rapid production of modified large area graphene.

  11. High Extraction Phosphors for Solid State Lighting

    SciTech Connect

    Summers, Chris; Menkara, Hisham; Wagner, Brent

    2011-09-01

    We have developed high-index, high efficiency bulk luminescent materials and novel nano-sized phosphors for improved solid-state white LED lamps. These advances can potentially contribute to reducing the loss in luminous efficiencies due to scattering, re-absorption, and thermal quenching. The bulk and nanostructured luminescent materials investigated are index matched to GaN and have broad and size-tunable absorption bands, size and impurity tuned emission bands, size-driven elimination of scattering effects, and a separation between absorption and emission bands. These innovations were accomplished through the use of novel synthesis techniques suitable for high volume production for LED lamp applications. The program produced a full-color set of high quantum yield phosphors with high chemical stability. In the bulk phosphor study, the ZnSeS:Cu,Ag phosphor was optimized to achieve >91% efficiency using erbium (Er) and other activators as sensitizers. Detailed analysis of temperature quenching effects on a large number of ZnSeS:Cu,Ag,X and strontium- and calcium-thiogallate phosphors lead to a breakthrough in the understanding of the anti-quenching behavior and a physical bandgap model was developed of this phenomena. In a follow up to this study, optimized phosphor blends for high efficiency and color performance were developed and demonstrated a 2-component phosphor system with good white chromaticity, color temperature, and high color rendering. By extending the protocols of quantum dot synthesis, large nanocrystals, greater than 20 nm in diameter were synthesized and exhibited bulk-like behavior and blue light absorption. The optimization of ZnSe:Mn nanophosphors achieved ~85% QE The limitations of core-shell nanocrystal systems were addressed by investigating alternative deltadoped structures. To address the manufacturability of these systems, a one-pot manufacturing protocol was developed for ZnSe:Mn nanophosphors. To enhance the stability of these material

  12. Luminescence and application of red-emitting phosphors of Eu3+-activated R2Zr3(MoO4)9 ( R = La, Sm, Gd)

    NASA Astrophysics Data System (ADS)

    Qi, Shuyun; Huang, Yanlin; Cheng, Han; Seo, Hyo Jin

    2016-01-01

    New red-emitting phosphors R2Zr3(MoO4)9:Eu3+ ( R = La, Sm, Gd) were prepared using the convenient solid-state reaction method. The samples were characterized by X-ray powder diffraction (XRD) measurements and structural refinements. The luminescence properties were investigated by photoluminescence spectra, decay curves, and absolute internal quantum efficiency (QE). The phosphors exhibited bright red luminescence corresponding to the electric dipole transition 5D0→7F2 at 615 nm under near UV light excitation. The thermal stability of the luminescence was investigated using temperature-dependent intensities at temperatures from 20 to 170°C. The results indicate that Gd2Zr3(MoO4)9:Eu3+ could be potentially considered for lighting due to its qualities, including their excitation spectra, QEs, red color coordinates, and thermal stability. [Figure not available: see fulltext.

  13. Crystal structure and luminescence properties of Bi3+activated Ca2Y8(SiO4)6O2 phosphors under near UV excitation

    NASA Astrophysics Data System (ADS)

    Sun, Zhihua; Wang, Minqiang; Yang, Zhi; Liu, Kaiping; Zhu, Feiyan

    2016-07-01

    Oxyapatite Ca2Y8-x(SiO4)6O2:xBi3+phosphor has been prepared via high temperature solid-state reaction. Its crystal structure and PL properties were investigated by X-ray diffraction, photoluminescence excitation and emission spectra. The results indicated that the Ca2Y8(SiO4)6O2 crystallizes as a hexagonal structure with a space group of P63/m and lattice constants of a=b=9.3507 Å, c=6.7899 Å, α=β=90.00°, γ=120.00°, V=514.14 Å3; The phosphor has two prominent emission bands: when excited under 320-360 nm, the phosphors emit a broad band centered at 495 nm due to the 3P1-1S0 transition of Bi3+ in 4f (C3) sites; when excited under 380 nm, the phosphors emit a broad band centered at 411 nm due to the 3P1-1S0 transition of Bi3+ in 6h (Cs) sites. The emission color varies from the greenish blue to blue as the excitation wavelength increases from 335 to 380 nm. The optimal intensity of emission band was observed when x=0.015 in the Ca2Y8-x(SiO4)6O2:xBi3+ series. The average critical distance Rc among Bi3+ ions is determined to be 20.15 Å.

  14. Waste recycling by vermicomposting: Maturity and quality assessment via dehydrogenase enzyme activity, lignin, water soluble carbon, nitrogen, phosphorous and other indicators.

    PubMed

    Alidadi, Hossein; Hosseinzadeh, Ahmad; Najafpoor, Ali Asghar; Esmaili, Habibollah; Zanganeh, Jafar; Dolatabadi Takabi, Maryam; Piranloo, Fardin Ghasemy

    2016-11-01

    Present study aims to examine the dynamics of maturation and qualification indicators in various vermicompost treatments and selection of the best treatment along with best maturation time in this regard. In this empirical study, dynamics of chemical (pH, electrical conductivity (EC), total nitrogen (TN), phosphorous, lignin, water soluble carbon (WSC), C/N, NH4/NO3) and biological (dehydrogenase enzyme (DEH) and DEH/WSC) properties were investigated in four various treatments, including various ratios of compost produced from municipal solid waste (MSW) and carbonaceous materials (50:50, 70:30, 85:15 and 100:0) over 100 days. Results showed a significant fluctuation in EC, DEH and DEH/WSC proportions over the process. In addition, a noticeable increase was observed for the dynamics of TN, phosphorous and lignin. In contrast, the C/N, NH4/NO3 and WSC values gradually decreased during the process. Moreover, it was observed that the length of 75 days for the process is an appropriate time for maturation of all treatments. However, the first and second treatments resulted in better outcomes compared with the other types of treatments. From the point of view of quality obtained vermicompost was nitrogen enriched product in all treatments. Whereas, for the phosphorous elements this method is appropriate for the first treatment only. PMID:27472049

  15. "JCE" Classroom Activity #109: My Acid Can Beat Up Your Acid!

    ERIC Educational Resources Information Center

    Putti, Alice

    2011-01-01

    In this guided-inquiry activity, students investigate the ionization of strong and weak acids. Bead models are used to study acid ionization on a particulate level. Students analyze seven strong and weak acid models and make generalizations about the relationship between acid strength and dissociation. (Contains 1 table and 2 figures.)

  16. Single-Layer, Multicolor Electroluminescent Phosphors

    NASA Technical Reports Server (NTRS)

    Robertson, James B.

    1988-01-01

    Etching eliminated in producing phosphor layers for displays. New process enables production of single-layer, two-color phosphor layer without etching. Method of construction, beginning with glass substrate with electrode and insulator layers, involves deposition of green phosphor masking with metal mask or photoresist; diffusion or ion implantation of manganese through mask to produce red phosphor and removal of mask.

  17. Polymorphism of phosphoric oxide

    USGS Publications Warehouse

    Hill, W.L.; Faust, G.T.; Hendricks, S.B.

    1943-01-01

    The melting points and monotropic relationship of three crystalline forms of phosphoric oxide were determined by the method of quenching. Previous vapor pressure data are discussed and interpreted to establish a pressure-temperature diagram (70 to 600??) for the one-component system. The system involves three triple points, at which solid, liquid and vapor (P4O10) coexist in equilibrium, namely: 420?? and 360 cm., 562?? and 43.7 cm. and 580?? and 55.5 cm., corresponding to the hexagonal, orthorhombic and stable polymorphs, respectively, and at least two distinct liquids, one a stable polymer of the other, which are identified with the melting of the stable form and the hexagonal modification, respectively. Indices of refraction of the polymorphs and glasses were determined. The density and the thermal, hygroscopic and structural properties of the several phases are discussed.

  18. Custom blending of lamp phosphors

    NASA Technical Reports Server (NTRS)

    Klemm, R. E.

    1978-01-01

    Spectral output of fluorescent lamps can be precisely adjusted by using computer-assisted analysis for custom blending lamp phosphors. With technique, spectrum of main bank of lamps is measured and stored in computer memory along with emission characteristics of commonly available phosphors. Computer then calculates ratio of green and blue intensities for each phosphor according to manufacturer's specifications and plots them as coordinates on graph. Same ratios are calculated for measured spectrum. Once proper mix is determined, it is applied as coating to fluorescent tubing.

  19. Antioxidant and antimicrobial activities of cinnamic acid derivatives.

    PubMed

    Sova, M

    2012-07-01

    Cinnamic acid is an organic acid occurring naturally in plants that has low toxicity and a broad spectrum of biological activities. In the search for novel pharmacologically active compounds, cinnamic acid derivatives are important and promising compounds with high potential for development into drugs. Many cinnamic acid derivatives, especially those with the phenolic hydroxyl group, are well-known antioxidants and are supposed to have several health benefits due to their strong free radical scavenging properties. It is also well known that cinnamic acid has antimicrobial activity. Cinnamic acid derivatives, both isolated from plant material and synthesized, have been reported to have antibacterial, antiviral and antifungal properties. Acids, esters, amides, hydrazides and related derivatives of cinnamic acid with such activities are here reviewed.

  20. Acid phosphatase and protease activities in immobilized rat skeletal muscles

    NASA Technical Reports Server (NTRS)

    Witzmann, F. A.; Troup, J. P.; Fitts, R. H.

    1982-01-01

    The effect of hind-limb immobilization on selected Iysosomal enzyme activities was studied in rat hing-limb muscles composed primarily of type 1. 2A, or 2B fibers. Following immobilization, acid protease and acid phosphatase both exhibited signifcant increases in their activity per unit weight in all three fiber types. Acid phosphatase activity increased at day 14 of immobilization in the three muscles and returned to control levels by day 21. Acid protease activity also changed biphasically, displaying a higher and earlier rise than acid phosphatase. The pattern of change in acid protease, but not acid phosphatase, closely parallels observed muscle wasting. The present data therefore demonstrate enhanced proteolytic capacity of all three fiber types early during muscular atrophy. In addition, the data suggest a dependence of basal hydrolytic and proteolytic activities and their adaptive response to immobilization on muscle fiber composition.

  1. Determination of ultra-micro amounts of sulfur in igneous rocks by spectrofluorimetry using 2-(o-hydroxyphenyl) benzoxazole derivatization and tin(II)-strong phosphoric acid-assisted reduction.

    PubMed

    Hong, Y D; Namgung, S W; Yoshida, M; Malik, A

    2000-02-01

    A new and very sensitive method was developed for the determination of ultra-micro amounts of sulfur in igneous rock samples. The sulfur compounds in an igneous rock sample are reduced and released in the form of hydrogen sulfide by heating with a tin(II)-strong phosphoric acid (SPA) reagent. The liberated hydrogen sulfide is carried by a flow of nitrogen into a copper(II) absorbing solution to obtain a precipitate of copper(II) sulfide. The remaining copper(II) ion forms a chelate with 2-(o-hydroxyphenyl)benzoxazole (HPB) and quenches the fluorescence of HPB. The amount of sulfide is determined by measuring the HPB fluorescence intensity. The optimum reaction conditions were stoichiometrically investigated. By the present method using 0.1-0.2 g of rock sample, ultramicro amounts of sulfur (0.1-12.8 mug) could be quantitatively separated, collected, and determined with a relative standard deviation of 1.37% for a sample containing 5.7 mug of sulfur (95% confidence level). PMID:18967860

  2. Determination of ultra-micro amounts of sulfur in igneous rocks by spectrofluorimetry using 2-(o-hydroxyphenyl) benzoxazole derivatization and tin(II)-strong phosphoric acid-assisted reduction.

    PubMed

    Hong, Y D; Namgung, S W; Yoshida, M; Malik, A

    2000-02-01

    A new and very sensitive method was developed for the determination of ultra-micro amounts of sulfur in igneous rock samples. The sulfur compounds in an igneous rock sample are reduced and released in the form of hydrogen sulfide by heating with a tin(II)-strong phosphoric acid (SPA) reagent. The liberated hydrogen sulfide is carried by a flow of nitrogen into a copper(II) absorbing solution to obtain a precipitate of copper(II) sulfide. The remaining copper(II) ion forms a chelate with 2-(o-hydroxyphenyl)benzoxazole (HPB) and quenches the fluorescence of HPB. The amount of sulfide is determined by measuring the HPB fluorescence intensity. The optimum reaction conditions were stoichiometrically investigated. By the present method using 0.1-0.2 g of rock sample, ultramicro amounts of sulfur (0.1-12.8 mug) could be quantitatively separated, collected, and determined with a relative standard deviation of 1.37% for a sample containing 5.7 mug of sulfur (95% confidence level).

  3. Decoupling of dynamic processes in surfactant-based liquid mixtures: the case of lithium-containing bis(2-ethylhexyl)phosphoric acid/bis(2-ethylhexyl)amine systems.

    PubMed

    Nicotera, Isabella; Oliviero Rossi, Cesare; Turco Liveri, Vincenzo; Calandra, Pietro

    2014-07-22

    Pure surfactant liquids and their binary mixtures, because of the amphiphilic nature of the molecules involved, can exhibit nanosegregation and peculiar transport properties. The idea that inspired this work is that the possibility of including in such media salts currently used for technological applications should lead to a synergy between the properties of the salt and those of the medium. Therefore, the dynamic features of bis(2-ethylhexyl)amine (BEEA) and bis(2-ethylhexyl)phosphoric acid (HDEHP) liquid mixtures were investigated as a function of composition and temperature by (1)H nuclear magnetic resonance (NMR) spectroscopy and rheometry. Inclusion of litium trifluoromethanesulfonate (LiT) has been investigated by infrared spectroscopy, pulsed field gradient NMR, and conductimetry methods to highlight the solubilizing and confining properties of these mixtures as well as the lithium conductivity. It was found that BEEA/HDEHP binary liquid mixtures show zero-threshold percolating self-assembly with a maximum in viscosity and a minimum in molecular diffusion at a 1:1 composition. Dissolution of LiT in such system can occur via confinement in the locally self-assembled polar domains. Despite this confinement, Li(+) conduction is scarcely dependent on the medium composition because of the possibility of a field-induced hopping decoupled by the structural and dynamical features of the medium.

  4. Influence of processing parameters on long lasting hybrid phosphor for LED applications

    NASA Astrophysics Data System (ADS)

    Jain, Abhilasha; Kumar, Ashwini; Dhoble, S. J.; Peshwe, D. R.

    2016-05-01

    Rare earth activated hybrid phosphors have made significant progress in terms of better light output, color properties and potential for long life. All these features coupled with low cost production and reduced maintenance have offered phosphor converted LEDs for diverse optoelectronic applications including signal lighting in advanced aviation. The present paper explores the effect of various processing parameters on luminescent hybrid phosphors fabricated through combustion synthesis.

  5. Study on TL and OSL characteristics of indigenously developed CaF 2:Mn phosphor

    NASA Astrophysics Data System (ADS)

    Bakshi, A. K.; Dhabekar, Bhushan; Rawat, N. S.; Singh, S. G.; Joshi, V. J.; Kumar, Vijay

    2009-02-01

    CaF 2:Mn phosphor is known for its high thermoluminescent sensitivity and dose linearity up to few kGy. In the present study CaF 2 phosphor with different concentration of Mn dopant was prepared and was characterized through different techniques. The phosphor was prepared through chemical root using CaCO 3, HF acid and MnCl 2 as raw materials following co-precipitation method. TL sensitivity of the prepared phosphor was compared with other well established phosphors used for radiation dosimetry. It was found that the TL sensitivity is higher by a factor of 10 with respect to LiF:Mg, Ti, TLD-100 and half to that of CaSO 4:Dy (0.05 mol%) phosphor. X-ray diffraction, TL emission spectrum and ESR spectrum taken of the prepared phosphor confirms the crystal structure, Mn 2+ emission and incorporation Mn in the crystal, respectively. No significant fading of the dosimetric peak was observed of the prepared phosphor for a storage period of 45 days. The dose linearity of the phosphor was found to be in the range of 50 Gy-3 kGy within an uncertainty of about 10%. An attempt was made to determine the kinetic parameters of TL glow curve and the parameters related to optically stimulated luminescence. In view of its long range of dose linearity, it can be used for the dosimetry of commercial irradiator generally used for the irradiation of food and grains in our country.

  6. Thermoluminescence characteristics of LiF: Cu nanocrystalline phosphor

    NASA Astrophysics Data System (ADS)

    Seth, Pooja; Aggarwal, Shruti

    2016-05-01

    Copper (Cu) activated LiF phosphor in nanocrystalline form has been prepared by the chemical co-precipitation method for radiation dosimetry application. The formation of nanocrystalline structure has been confirmed by X-ray diffraction and Scanning electron microscopy. Cubical shaped nanostructure with average particle size of 33nm has been formed. The sample was prepared at different concentration of Cu from 0.01mol% to 3 mol%. TL properties were investigated by studying the glow curve after irradiating the phosphor to gamma ray Co60 source with dose of 15 Gy. It has been found that nanocrystalline LiF: Cu show simple glow curve structure with a single glow peak at 404 K where as commercially available phosphors exhibits multi peak complex glow curve structure. The effect of different normality on the TL properties of phosphor has been studied. Maximum TL intensity for LiF: Cu (0.1mol %) phosphor is observed at the normality of 0.5N and annealing temperature of 200°C. The phosphor showed good linearity up to 10 KGy.

  7. Bright luminescence from pure DNA-curcumin-based phosphors for bio hybrid light-emitting diodes.

    PubMed

    Reddy, M Siva Pratap; Park, Chinho

    2016-01-01

    Recently, significant advances have occurred in the development of phosphors for bio hybrid light-emitting diodes (Bio-HLEDs), which have created brighter, metal-free, rare-earth phosphor-free, eco-friendly, and cost-competitive features for visible light emission. Here, we demonstrate an original approach using bioinspired phosphors in Bio-HLEDs based on natural deoxyribonucleic acid (DNA)-curcumin complexes with cetyltrimethylammonium (CTMA) in bio-crystalline form. The curcumin chromophore was bound to the DNA double helix structure as observed using field emission tunnelling electron microscopy (FE-TEM). Efficient luminescence occurred due to tightly bound curcumin chromophore to DNA duplex. Bio-HLED shows low luminous drop rate of 0.0551 s(-1). Moreover, the solid bio-crystals confined the activating bright luminescence with a quantum yield of 62%, thereby overcoming aggregation-induced quenching effect. The results of this study herald the development of commercially viable large-scale hybrid light applications that are environmentally benign. PMID:27572113

  8. Bright luminescence from pure DNA-curcumin–based phosphors for bio hybrid light-emitting diodes

    NASA Astrophysics Data System (ADS)

    Reddy, M. Siva Pratap; Park, Chinho

    2016-08-01

    Recently, significant advances have occurred in the development of phosphors for bio hybrid light-emitting diodes (Bio-HLEDs), which have created brighter, metal-free, rare-earth phosphor-free, eco-friendly, and cost-competitive features for visible light emission. Here, we demonstrate an original approach using bioinspired phosphors in Bio-HLEDs based on natural deoxyribonucleic acid (DNA)-curcumin complexes with cetyltrimethylammonium (CTMA) in bio-crystalline form. The curcumin chromophore was bound to the DNA double helix structure as observed using field emission tunnelling electron microscopy (FE-TEM). Efficient luminescence occurred due to tightly bound curcumin chromophore to DNA duplex. Bio-HLED shows low luminous drop rate of 0.0551 s‑1. Moreover, the solid bio-crystals confined the activating bright luminescence with a quantum yield of 62%, thereby overcoming aggregation-induced quenching effect. The results of this study herald the development of commercially viable large-scale hybrid light applications that are environmentally benign.

  9. Bright luminescence from pure DNA-curcumin-based phosphors for bio hybrid light-emitting diodes.

    PubMed

    Reddy, M Siva Pratap; Park, Chinho

    2016-01-01

    Recently, significant advances have occurred in the development of phosphors for bio hybrid light-emitting diodes (Bio-HLEDs), which have created brighter, metal-free, rare-earth phosphor-free, eco-friendly, and cost-competitive features for visible light emission. Here, we demonstrate an original approach using bioinspired phosphors in Bio-HLEDs based on natural deoxyribonucleic acid (DNA)-curcumin complexes with cetyltrimethylammonium (CTMA) in bio-crystalline form. The curcumin chromophore was bound to the DNA double helix structure as observed using field emission tunnelling electron microscopy (FE-TEM). Efficient luminescence occurred due to tightly bound curcumin chromophore to DNA duplex. Bio-HLED shows low luminous drop rate of 0.0551 s(-1). Moreover, the solid bio-crystals confined the activating bright luminescence with a quantum yield of 62%, thereby overcoming aggregation-induced quenching effect. The results of this study herald the development of commercially viable large-scale hybrid light applications that are environmentally benign.

  10. Bright luminescence from pure DNA-curcumin–based phosphors for bio hybrid light-emitting diodes

    PubMed Central

    Reddy, M. Siva Pratap; Park, Chinho

    2016-01-01

    Recently, significant advances have occurred in the development of phosphors for bio hybrid light-emitting diodes (Bio-HLEDs), which have created brighter, metal-free, rare-earth phosphor-free, eco-friendly, and cost-competitive features for visible light emission. Here, we demonstrate an original approach using bioinspired phosphors in Bio-HLEDs based on natural deoxyribonucleic acid (DNA)-curcumin complexes with cetyltrimethylammonium (CTMA) in bio-crystalline form. The curcumin chromophore was bound to the DNA double helix structure as observed using field emission tunnelling electron microscopy (FE-TEM). Efficient luminescence occurred due to tightly bound curcumin chromophore to DNA duplex. Bio-HLED shows low luminous drop rate of 0.0551 s−1. Moreover, the solid bio-crystals confined the activating bright luminescence with a quantum yield of 62%, thereby overcoming aggregation-induced quenching effect. The results of this study herald the development of commercially viable large-scale hybrid light applications that are environmentally benign. PMID:27572113

  11. Fluxless soldering using activated acid vapors

    SciTech Connect

    Frear, D.R.; Keicher, D.M.

    1992-01-01

    Acid vapors have been used to fluxlessly reduce metal oxides and enhance wetting of solder on metallizations. Dilute solutions of hydrogen, acetic acid and formic acid in an inert carrier gas of nitrogen or argon were used with the sessile drop technique for 60Sn-40 Pb solder on Cu and Au/Ni metallizations. The time to reduce metal oxides and the extent of wetting as a function of acid vapor concentrations were characterized. Acetic and formic acids reduce the surface metal oxides sufficiently to form metallurgically sound solder joints. Hydrogen did not reduce oxides rapidly enough at 220{degree}C to be suitable for soldering applications. The optimum conditions for oxide reduction with formic acid was with an acid vapor concentration in nitrogen carrier gas of 4% for Cu metallizations and 1.6% on Au/Ni. The acetic acid vapor concentration, also in nitrogen, was optimized at 1.5% for both metallizations. Above a vapor concentration of 1.5%, the acetic acid combined with the bare metal to form acetates which increased the wetting time. These results indicate that acid vapor fluxless soldering is a viable alternative to traditional flux soldering.

  12. Luminescence improvement in Pr{sup 3+} and Gd{sup 3+} activated Sr{sub 2}Mg(BO{sub 3}){sub 2} inorganic phosphor

    SciTech Connect

    Gawande, A.B.; Sonekar, R.P.; Omanwar, S.K.

    2014-12-15

    Highlights: • Sr{sub 2}Mg(BO{sub 3}){sub 2} doped Gd{sup 3+} and Pr{sup 3+} have been synthesized by solution combustion synthesis technique. • Effect of doping concentration of Gd{sup 3+} and Pr{sup 3+} on the luminescence of synthesized material is discussed. • Effect of charge compensation by Li{sup +}, Na{sup +} and K{sup +} on emission intensity is studied in detail. • Efficient energy transfer from Pr{sup 3+} to Gd{sup 3+} in Sr{sub 2}Mg(BO{sub 3}){sub 2} was observed. • Optimum concentration and critical transfer distance for optimum concentration have been determined. - Abstract: The photoluminescence properties of (Sr{sub 1−x}Pr{sub x}){sub 2}Mg(BO{sub 3}){sub 2}; (Sr{sub 1−2x}Pr{sub x}M{sub x}){sub 2}Mg(BO{sub 3}){sub 2,} (M = Li, Na, K); (Sr{sub 1−x}Gd{sub x}){sub 2}Mg(BO{sub 3}){sub 2}; (Sr{sub 1−2x}Gd{sub x}M{sub x}){sub 2}Mg(BO{sub 3}){sub 2}, (M = Li, Na, K) and (Sr{sub 1−4x}Pr{sub x}Gd{sub x}Na{sub 2x}){sub 2}Mg(BO{sub 3}){sub 2} inorganic phosphors prepared by solution combustion synthesis technique are discussed. The structure of the prepared phosphor characterized using Thermogravimetric–differential thermal analysis, X-ray diffraction and fourier transform-infrared. Scanning electron microscopy images of the prepared materials show irregular grains with agglomerate phenomena. Photoluminescence properties were studied at room temperature. Optimum concentration and critical transfer distance of the synthesized phosphors were determined.

  13. High Temperature Thermographic Phosphor Coatings Development

    NASA Technical Reports Server (NTRS)

    Goedeke, Shawn; Allison, S. W.; Beshears, D. L.; Bencic, T.; Cates, M. R.; Hollerman, W. A.; Guidry, R.

    2003-01-01

    For many years, phosphor thermometry has been used for non-contact temperature measurements. A large number of applications have been associated with high temperatures, especially for aerospace systems where blackbody radiation backgrounds are large and in challenging environments, such as vibration, rotation, flame, or noise. These environments restrict the use of more common thermocouples or infrared thermometric techniques. In particular, temperature measurements inside jet turbines, rocket engines, or similar devices are especially amenable to phosphor techniques. Often the fluorescent materials are used as powders, either suspended in binders and applied like paint or applied as high-temperature sprays. Thin coatings that are less than 50 m thick are used on the surfaces of interest. These coatings will quickly assume the same temperature as the surface to which they are applied. The temperature dependence of fluorescent materials is a function of the base matrix atoms and a small quantity of added activator or dopant ions. Often for high temperature applications, the selected materials are refractory and include rare earth ions. Phosphors like Y3Al5O12 (YAG) doped with Eu, Dy, or Tm, Y2O3 doped with Eu, or similar rare earth compounds, will survive high temperatures and can be configured to emit light that changes rapidly in lifetime and intensity. For example, researchers at Oak Ridge National Laboratory recently observed fluorescence from YAG:Dy and YAG:Tm at temperatures above 1400 C. One of the biggest challenges is to locate a binder material that can withstand tremendous variations in temperature in an adverse aerospace environment. This poster will provide an overview into our attempt to utilize phosphors for thermometry purposes. Emphasis will be placed on the use of selected binder materials that can withstand high temperatures. This research was completed for the National Aeronautics and Space Administration's Glenn Research Center in Cleveland

  14. Endolysosomes Are the Principal Intracellular Sites of Acid Hydrolase Activity.

    PubMed

    Bright, Nicholas A; Davis, Luther J; Luzio, J Paul

    2016-09-12

    The endocytic delivery of macromolecules from the mammalian cell surface for degradation by lysosomal acid hydrolases requires traffic through early endosomes to late endosomes followed by transient (kissing) or complete fusions between late endosomes and lysosomes. Transient or complete fusion results in the formation of endolysosomes, which are hybrid organelles from which lysosomes are re-formed. We have used synthetic membrane-permeable cathepsin substrates, which liberate fluorescent reporters upon proteolytic cleavage, as well as acid phosphatase cytochemistry to identify which endocytic compartments are acid hydrolase active. We found that endolysosomes are the principal organelles in which acid hydrolase substrates are cleaved. Endolysosomes also accumulated acidotropic probes and could be distinguished from terminal storage lysosomes, which were acid hydrolase inactive and did not accumulate acidotropic probes. Using live-cell microscopy, we have demonstrated that fusion events, which form endolysosomes, precede the onset of acid hydrolase activity. By means of sucrose and invertase uptake experiments, we have also shown that acid-hydrolase-active endolysosomes and acid-hydrolase-inactive, terminal storage lysosomes exist in dynamic equilibrium. We conclude that the terminal endocytic compartment is composed of acid-hydrolase-active, acidic endolysosomes and acid hydrolase-inactive, non-acidic, terminal storage lysosomes, which are linked and function in a lysosome regeneration cycle. PMID:27498570

  15. Physiological activities of hydroxyl fatty acids

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the search of value-added products from surplus soybean oil, we produced many new hydroxy fatty acids through microbial bioconversion. Hydroxy fatty acids are used in a wide range of industrial products, such as resins, waxes, nylons plastics, lubricants, cosmetics, and additives in coatings and...

  16. Physical activity as a determinant of fecal bile acid levels

    PubMed Central

    Wertheim, Betsy C.; Martínez, María Elena; Ashbeck, Erin L.; Roe, Denise J.; Jacobs, Elizabeth T.; Alberts, David S.; Thompson, Patricia A.

    2009-01-01

    Physical activity is protective against colon cancer, whereas colonic bile acid exposure is a suspected risk factor. While likely related, the association between physical activity and bile acid levels has not been well studied. Furthermore, the effect of triglycerides, which are known to modify bile acid levels, on this relationship has not been investigated. We conducted a cross-sectional analysis of baseline fecal bile acid levels for 735 colorectal adenoma formers obtained from participants in a phase III ursodeoxycholic acid chemoprevention trial. Compared to the lowest quartile of recreational physical activity duration, the highest quartile was associated with a 17% lower fecal bile acid concentration, adjusted for age, sex, dietary fiber intake, and body mass index (P = 0.042). Furthermore, consistent with a previously established relationship between serum triglyceride levels and bile acid metabolism, we stratified by triglyceride level and observed a 34% lower fecal bile acid concentration (highest versus lowest quartiles of physical activity) in individuals with low triglycerides (< 136 mg/dL; P = 0.002). In contrast, no association between physical activity and fecal bile acid concentration was observed for subjects with high triglycerides (≥ 136 mg/dL). Our results suggest that the biological mechanism responsible for the protective effect of physical activity on the incidence of colon cancer may be partially mediated by decreasing colonic bile acid exposure. However, this effect may be limited to individuals with lower triglyceride levels. PMID:19383885

  17. From natural attapulgite to phosphor materials: Characterization, photoluminescence and structure

    SciTech Connect

    Wang, Wenjie; Gu, Zheng; Gao, Xiuping; Jiang, Huie; Liu, Weisheng

    2014-08-15

    Highlights: • Sr{sub 2.965}Al{sub 0.08}Si{sub 0.92}O{sub 5}:0.025Ce{sup 3+}, 0.01Eu{sup 2+} phosphor was synthesized from natural attapulgite. • Pure Sr{sub 3}SiO{sub 5} phase can be easily obtained. • It provides a new application field as phosphor for natural attapulgite. - Abstract: Sr{sub 2.965}Al{sub 0.08}Si{sub 0.92}O{sub 5}:0.025Ce{sup 3+}, 0.01Eu{sup 2+} (SrAlSiO:Ce{sup 3+}, Eu{sup 2+}) phosphor from natural attapulgite (ATP) was synthesized by solid-state reaction method. For the use of ATP as a source of Si and Al, pretreatment process including mechanical grinding and acid leaching were involved. X-ray diffraction patterns confirmed the formation of silicates in a wide temperature field, whereas Sr{sub 3}SiO{sub 5} within a single step. The ATP fibers were tuning into phosphor particles (about 1.5–3.0 μm) after calcination. Furthermore, photoluminescence spectra of the SrAlSiO:Ce{sup 3+}, Eu{sup 2+} phosphor was also in good agreement with the literature results, indicating a promising potential application as an effective candidate for warm-white LEDs materials.

  18. Croconaine rotaxane for acid activated photothermal heating and ratiometric photoacoustic imaging of acidic pH†

    PubMed Central

    Guha, Samit; Shaw, Gillian Karen; Mitcham, Trevor M.; Bouchard, Richard R.

    2015-01-01

    Absorption of 808 nm laser light by liposomes containing a pH sensitive, near-infrared croconaine rotaxane dye increases dramatically in weak acid. A stealth liposome composition permits acid activated, photothermal heating and also acts as an effective nanoparticle probe for ratiometric photoacoustic imaging of acidic pH in deep sample locations, including a living mouse. PMID:26502996

  19. Complex Leaching Process of Scheelite in Hydrochloric and Phosphoric Solutions

    NASA Astrophysics Data System (ADS)

    Liu, Liang; Xue, Jilai; Liu, Kang; Zhu, Jun; Wang, Zengjie

    2016-06-01

    The complex leaching process of synthetic scheelite and scheelite concentrate in hydrochloric and phosphoric solutions has been investigated for improving process efficiency. A higher leaching rate, compared with the classic acid leaching process, can be obtained through the synergy of HCl and H3PO4 with appropriate W/P mole ratio, temperature, and acid concentration. For synthetic scheelite, the optimum leaching conditions were W/P mole ratio 7:1, temperature 50°C, HCl 0.72 mol/L, and stirring speed 600 rpm; for scheelite concentrate, W/P mole ratio 7:1, temperature 80°C, HCl 2.16 mol/L, and stirring speed 1000 rpm. The leaching rates under the optimized conditions can reach up to 98% or even higher. FTIR spectra analysis confirmed that the leachate composition remained as H3[PW12O40] in the range of varying W/P mole ratios, so the PO4 3- in acidic solution and phosphorus content in the leaching product could be better controlled. The function 1 - (1 - X)1/3 against leaching time was applied to fit the experimental data, and the apparent activation energy, E a, was calculated as 60.65 kJ/mol. The results would be valuable for effectively using scheelite as a raw material resource for sustainable tungsten production.

  20. Complex Leaching Process of Scheelite in Hydrochloric and Phosphoric Solutions

    NASA Astrophysics Data System (ADS)

    Liu, Liang; Xue, Jilai; Liu, Kang; Zhu, Jun; Wang, Zengjie

    2016-09-01

    The complex leaching process of synthetic scheelite and scheelite concentrate in hydrochloric and phosphoric solutions has been investigated for improving process efficiency. A higher leaching rate, compared with the classic acid leaching process, can be obtained through the synergy of HCl and H3PO4 with appropriate W/P mole ratio, temperature, and acid concentration. For synthetic scheelite, the optimum leaching conditions were W/P mole ratio 7:1, temperature 50°C, HCl 0.72 mol/L, and stirring speed 600 rpm; for scheelite concentrate, W/P mole ratio 7:1, temperature 80°C, HCl 2.16 mol/L, and stirring speed 1000 rpm. The leaching rates under the optimized conditions can reach up to 98% or even higher. FTIR spectra analysis confirmed that the leachate composition remained as H3[PW12O40] in the range of varying W/P mole ratios, so the PO4 3- in acidic solution and phosphorus content in the leaching product could be better controlled. The function 1 - (1 - X)1/3 against leaching time was applied to fit the experimental data, and the apparent activation energy, E a, was calculated as 60.65 kJ/mol. The results would be valuable for effectively using scheelite as a raw material resource for sustainable tungsten production.

  1. Potentiometric Acid-Base Titrations with Activated Graphite Electrodes

    NASA Astrophysics Data System (ADS)

    Riyazuddin, P.; Devika, D.

    1997-10-01

    Dry cell graphite (DCG) electrodes activated with potassium permanganate are employed as potentiometric indicator electrodes for acid-base titrations. Special attention is given to an indicator probe comprising activated DCG-non-activiated DCG electrode couple. This combination also proves suitable for the titration of strong or weak acids.

  2. Natural cinnamic acids, synthetic derivatives and hybrids with antimicrobial activity.

    PubMed

    Guzman, Juan David

    2014-11-25

    Antimicrobial natural preparations involving cinnamon, storax and propolis have been long used topically for treating infections. Cinnamic acids and related molecules are partly responsible for the therapeutic effects observed in these preparations. Most of the cinnamic acids, their esters, amides, aldehydes and alcohols, show significant growth inhibition against one or several bacterial and fungal species. Of particular interest is the potent antitubercular activity observed for some of these cinnamic derivatives, which may be amenable as future drugs for treating tuberculosis. This review intends to summarize the literature data on the antimicrobial activity of the natural cinnamic acids and related derivatives. In addition, selected hybrids between cinnamic acids and biologically active scaffolds with antimicrobial activity were also included. A comprehensive literature search was performed collating the minimum inhibitory concentration (MIC) of each cinnamic acid or derivative against the reported microorganisms. The MIC data allows the relative comparison between series of molecules and the derivation of structure-activity relationships.

  3. High-speed phosphor thermometry.

    PubMed

    Fuhrmann, N; Baum, E; Brübach, J; Dreizler, A

    2011-10-01

    Phosphor thermometry is a semi-invasive surface temperature measurement technique utilising the luminescence properties of doped ceramic materials. Typically, these phosphor materials are coated onto the object of interest and are excited by a short UV laser pulse. Up to now, primarily Q-switched laser systems with repetition rates of 10 Hz were employed for excitation. Accordingly, this diagnostic tool was not applicable to resolve correlated temperature transients at time scales shorter than 100 ms. This contribution reports on the first realisation of a high-speed phosphor thermometry system employing a highly repetitive laser in the kHz regime and a fast decaying phosphor. A suitable material was characterised regarding its temperature lifetime characteristic and its measurement precision. Additionally, the influence of laser power on the phosphor coating was investigated in terms of heating effects. A demonstration of this high-speed technique has been conducted inside the thermally highly transient system of an optically accessible internal combustion engine. Temperatures have been measured with a repetition rate of 6 kHz corresponding to one sample per crank angle degree at 1000 rpm. PMID:22047319

  4. Inorganic Phosphor Materials for Lighting.

    PubMed

    Lin, Yuan-Chih; Karlsson, Maths; Bettinelli, Marco

    2016-04-01

    This chapter addresses the development of inorganic phosphor materials capable of converting the near UV or blue radiation emitted by a light emitting diode to visible radiation that can be suitably combined to yield white light. These materials are at the core of the new generation of solid-state lighting devices that are emerging as a crucial clean and energy saving technology. The chapter introduces the problem of white light generation using inorganic phosphors and the structure-property relationships in the broad class of phosphor materials, normally containing lanthanide or transition metal ions as dopants. Radiative and non-radiative relaxation mechanisms are briefly described. Phosphors emitting light of different colors (yellow, blue, green, and red) are described and reviewed, classifying them in different chemical families of the host (silicates, phosphates, aluminates, borates, and non-oxide hosts). This research field has grown rapidly and is still growing, but the discovery of new phosphor materials with optimized properties (in terms of emission efficiency, chemical and thermal stability, color, purity, and cost of fabrication) would still be of the utmost importance. PMID:27573146

  5. High-speed phosphor thermometry

    NASA Astrophysics Data System (ADS)

    Fuhrmann, N.; Baum, E.; Brübach, J.; Dreizler, A.

    2011-10-01

    Phosphor thermometry is a semi-invasive surface temperature measurement technique utilising the luminescence properties of doped ceramic materials. Typically, these phosphor materials are coated onto the object of interest and are excited by a short UV laser pulse. Up to now, primarily Q-switched laser systems with repetition rates of 10 Hz were employed for excitation. Accordingly, this diagnostic tool was not applicable to resolve correlated temperature transients at time scales shorter than 100 ms. This contribution reports on the first realisation of a high-speed phosphor thermometry system employing a highly repetitive laser in the kHz regime and a fast decaying phosphor. A suitable material was characterised regarding its temperature lifetime characteristic and its measurement precision. Additionally, the influence of laser power on the phosphor coating was investigated in terms of heating effects. A demonstration of this high-speed technique has been conducted inside the thermally highly transient system of an optically accessible internal combustion engine. Temperatures have been measured with a repetition rate of 6 kHz corresponding to one sample per crank angle degree at 1000 rpm.

  6. High-speed phosphor thermometry.

    PubMed

    Fuhrmann, N; Baum, E; Brübach, J; Dreizler, A

    2011-10-01

    Phosphor thermometry is a semi-invasive surface temperature measurement technique utilising the luminescence properties of doped ceramic materials. Typically, these phosphor materials are coated onto the object of interest and are excited by a short UV laser pulse. Up to now, primarily Q-switched laser systems with repetition rates of 10 Hz were employed for excitation. Accordingly, this diagnostic tool was not applicable to resolve correlated temperature transients at time scales shorter than 100 ms. This contribution reports on the first realisation of a high-speed phosphor thermometry system employing a highly repetitive laser in the kHz regime and a fast decaying phosphor. A suitable material was characterised regarding its temperature lifetime characteristic and its measurement precision. Additionally, the influence of laser power on the phosphor coating was investigated in terms of heating effects. A demonstration of this high-speed technique has been conducted inside the thermally highly transient system of an optically accessible internal combustion engine. Temperatures have been measured with a repetition rate of 6 kHz corresponding to one sample per crank angle degree at 1000 rpm.

  7. Oxidative Dehydrogenation of Isobutane on Phosphorous-Modified Graphitic Mesoporous Carbon

    SciTech Connect

    Schwartz, Viviane; Xie, Hong; Meyer III, Harry M; Overbury, Steven {Steve} H; Liang, Chengdu

    2011-01-01

    Phosphorous heteroatoms were added in order to tune the selectivity and investigate the roles of different oxygen species in graphitic mesoporous carbons for the oxidative dehydrogenation reaction of isobutane to isobutene. Small changes in the apparent isobutane activation energy are consistent with the notion that the phosphorous groups do not change the nature of the active sites but they interfere with the availability of the sites. Our results show that the improvement on selectivity is not proportional to the amount of phosphorous added. Small phosphorous content improved the selectivity by suppressing the combustion of isobutane. However, a higher amount of phosphorous groups lead to coverage of selective quinone sites and/or creation of active sites favorable to total oxidation.

  8. Simultaneous production of l-lactic acid with high optical activity and a soil amendment with food waste that demonstrates plant growth promoting activity.

    PubMed

    Kitpreechavanich, Vichien; Hayami, Arisa; Talek, Anfal; Chin, Clament Fui Seung; Tashiro, Yukihiro; Sakai, Kenji

    2016-07-01

    A unique method to produce highly optically-active l-lactic acid and soil amendments that promote plant growth from food waste was proposed. Three Bacillus strains Bacillus subtilis KBKU21, B. subtilis N3-9 and Bacillus coagulans T27, were used. Strain KBKU21 accumulated 36.9 g/L l-lactic acid with 95.7% optical activity and 98.2% l-lactic acid selectivity when fermented at 43°C for 84 h in a model kitchen refuse (MKR) medium. Residual precipitate fraction (anaerobically-fermented MKR (AFM) compost) analysis revealed 4.60%, 0.70% and 0.75% of nitrogen (as N), phosphorous (as P2O5), and potassium (as K2O), respectively. Additionally, the carbon to nitrogen ratio decreased from 13.3 to 10.6. AFM compost with KBKU21 promoted plant growth parameters, including leaf length, plant height and fresh weight of Brassica rapa (Komatsuna), than that by chemical fertilizers or commercial compost. The concept provides an incentive for the complete recycling of food waste, contributing towards a sustainable production system.

  9. Simultaneous production of l-lactic acid with high optical activity and a soil amendment with food waste that demonstrates plant growth promoting activity.

    PubMed

    Kitpreechavanich, Vichien; Hayami, Arisa; Talek, Anfal; Chin, Clament Fui Seung; Tashiro, Yukihiro; Sakai, Kenji

    2016-07-01

    A unique method to produce highly optically-active l-lactic acid and soil amendments that promote plant growth from food waste was proposed. Three Bacillus strains Bacillus subtilis KBKU21, B. subtilis N3-9 and Bacillus coagulans T27, were used. Strain KBKU21 accumulated 36.9 g/L l-lactic acid with 95.7% optical activity and 98.2% l-lactic acid selectivity when fermented at 43°C for 84 h in a model kitchen refuse (MKR) medium. Residual precipitate fraction (anaerobically-fermented MKR (AFM) compost) analysis revealed 4.60%, 0.70% and 0.75% of nitrogen (as N), phosphorous (as P2O5), and potassium (as K2O), respectively. Additionally, the carbon to nitrogen ratio decreased from 13.3 to 10.6. AFM compost with KBKU21 promoted plant growth parameters, including leaf length, plant height and fresh weight of Brassica rapa (Komatsuna), than that by chemical fertilizers or commercial compost. The concept provides an incentive for the complete recycling of food waste, contributing towards a sustainable production system. PMID:26819060

  10. Rapid method of separating Am(VI) from transplutonium and rare-earth elements on a cation exchanger in phosphoric acid

    SciTech Connect

    Tikhomirova, G.S.; Guseva, L.I.

    1988-07-01

    Measurements have been made on cation-exchanger sorption of americium, other actinoids, and certain rare-earth elements from 0.1-2.0 M H/sub 3/PO/sub 4/ when the elements have been oxidized with ammonium persulfate alone or mixed with silver phosphate. There are considerable differences in behavior between the americium and the other elements on account of its being oxidized to a higher valency state. Measurements have been made on the effects of acid and oxidant concentrations and of the oxidation and elution conditions on the americium yield when the exchanger is treated with H/sub 3/PO/sub 4/. Optimum oxidation conditions have been chosen, and a rapid method has been devised for separating americium(VI) from other transplutonium elements and REE on Dowex 50 /times/ 8, where the eluent is 0.1-1.0 M H/sub 3/PO/sub 4/ plus 0.05 M (NH/sub 4/)/sub 2/S/sub 2/O/sub 8/.

  11. [Biological activity of retinoic acid and methylretinoate].

    PubMed

    Dusheĭko, A A; Chernukhina, L A; Blazhevich, M A; Davydova, L P

    1980-01-01

    Vitamin A lack in the diet of chicken produces a significant increase in the glandular stomach as well as formation of erosions and ulcers on the surface of the mucous membrane of the intermediate zone. Replacement of retinyl acetate in the diet by retinoic acid or methyl retionate gives no rise to changes in the morphological integrity of the glandular stomach of the chickens. Moreover, these compounds produce a reverse development of vitamin A-induced changes. It is thus concluded that when the diet lacks vitamin A, both retinoic acid and methyl retionate are capable of maintaining the structural integrity of the stomach.

  12. Perfluoroalkyl acids : Recent activities and research progress

    EPA Science Inventory

    The perfluoroalkyl acids (PFAAs) are a family of man-made fluorinated organic chemicals consisting of a carbon backbone typically of four to fourteen in length and a charged functional moiety (primarily carboxylate, sulfonate or phosphonate). The two most widely known PFAAs are ...

  13. Chlorogenic Acid Inhibits Human Platelet Activation and Thrombus Formation

    PubMed Central

    Fuentes, Eduardo; Caballero, Julio; Alarcón, Marcelo; Rojas, Armando; Palomo, Iván

    2014-01-01

    Background Chlorogenic acid is a potent phenolic antioxidant. However, its effect on platelet aggregation, a critical factor in arterial thrombosis, remains unclear. Consequently, chlorogenic acid-action mechanisms in preventing platelet activation and thrombus formation were examined. Methods and Results Chlorogenic acid in a dose-dependent manner (0.1 to 1 mmol/L) inhibited platelet secretion and aggregation induced by ADP, collagen, arachidonic acid and TRAP-6, and diminished platelet firm adhesion/aggregation and platelet-leukocyte interactions under flow conditions. At these concentrations chlorogenic acid significantly decreased platelet inflammatory mediators (sP-selectin, sCD40L, CCL5 and IL-1β) and increased intraplatelet cAMP levels/PKA activation. Interestingly, SQ22536 (an adenylate cyclase inhibitor) and ZM241385 (a potent A2A receptor antagonist) attenuated the antiplatelet effect of chlorogenic acid. Chlorogenic acid is compatible to the active site of the adenosine A2A receptor as revealed through molecular modeling. In addition, chlorogenic acid had a significantly lower effect on mouse bleeding time when compared to the same dose of aspirin. Conclusions Antiplatelet and antithrombotic effects of chlorogenic acid are associated with the A2A receptor/adenylate cyclase/cAMP/PKA signaling pathway. PMID:24598787

  14. Surface-active properties of humic and sulfochlorohumic acids

    SciTech Connect

    Ryabova, I.N.; Mustafina, G.A.; Akkulova, Z.G.; Satymbaeva, A.S.

    2009-10-15

    The surface tension of alkaline solutions of humic acids and their sulfochloroderivatives, which are synthesized by sulfonation of chlorohumic acids isolated from coal chlorinated by the electrochemical method, is investigated. It is established that humic compounds possess weak surface activity. Basic adsorption parameters are calculated.

  15. Effect of phosphoric fertilizer and starter rates of nitrogen fertilizers on the phosphatase activity in the rhizosphere soil and nonlignified soybean roots under drought conditions

    NASA Astrophysics Data System (ADS)

    Emnova, E. E.; Daraban, O. V.; Bizgan, I. V.; Toma, S. I.

    2014-02-01

    In a small-plot field experiment, two soybean ( Glycine max L.) cultivars were grown on a calcareous chernozem under the drought conditions of 2012 with the preplanting application of simple superphosphate (Ps) at 60 kg/ha, urea (Nu) at 10 and 20 kg/ha, and ammonium nitrate (Nan) at 20 kg/ha. The phosphatase activity was measured in the rhizosphere soil (0- to 20-cm layer) and the fine nonlignified roots of soybean plants at the blossoming and pod-formation stages (the soil water content was 19 and 33% of the total water capacity, respectively). The maximum content of available phosphorus in the rhizosphere of both soybean cultivars (4.3-4.8 mg/100 g dry soil) was found at the simultaneous application of Ps and Nu20. Higher activities of the predominant phosphatases (alkaline phosphatase in the rhizosphere and acid phosphatase in the roots) were observed in the root-inhabited zone of the soil under the Indra cultivar compared to the Aura cultivar, which correlated with the lower content of available phosphorus in the rhizosphere soil (especially at the simultaneous application of Ps and Nu20) and the higher productivity of this cultivar in this treatment.

  16. Synthesis and evaluation of dioleoyl glyceric acids showing antitrypsin activity.

    PubMed

    Habe, Hiroshi; Fukuoka, Tokuma; Sato, Shun; Kitamoto, Dai; Sakaki, Keiji

    2011-01-01

    Previously, Lešová et al. reported the isolation and identification of metabolite OR-1, showing antitrypsin activity, produced during fermentation by Penicillium funiculosum. The structure of OR-1 was a mixture of glyceric acid (GA), esterified with C(14)-C(18) fatty acids, and oleic acid (C18:1) as the most predominant fatty acid (Folia Microbiol. 46, 21-23, 2001). In this study, dioleoyl D-GA and dioleoyl L-GA were synthesized via diesterification with oleoyl chloride, and their antitrypsin activities were evaluated using both a disk diffusion method and spectral absorption measurements. The results show that both compounds and their equivalent mixtures possess antitrypsin activities; however, their IC(50) values (approximately 2 mM) are much higher than that of OR-1 (4.25 µM), suggesting that dioleoyl GA does not play a major role in the OR-1 antitrypsin activity. PMID:21606621

  17. Multiple forms of acid phosphatase activity in Gaucher's disease.

    PubMed

    Chambers, J P; Peters, S P; Glew, R H; Lee, R E; McCafferty, L R; Mercer, D W; Wenger, D A

    1978-07-01

    Although the primary genetic defect in all individuals with Gaucher's disease is a deficiency in glucocerebrosidase activity, the finding of marked elevations in splenic and serum acid phosphatase activity is almost as consistent a finding. Gaucher spleen and serum contain at least two forms of acid phosphatase that can be readily separated by chromatography on columns containing the cation exchange resin Sulphopropyl Sephadex. The major species of acid phosphatase (designated SP-I) contained in Triton X-100 (1% v/v) extracts of Gaucher spleen accounts for 65%--95% of the total activity and has the following properties: (1) it does not bind to the cation exchange column; (2) it exhibitis a pH optimum of 4.5--5.0; (3) it is inhibited by sodium fluoride (15 mM), L(+)-tartaric acid (20 mM), and beta-mercaptoethanol (2.1 M), and (4) it is resistant to inhibition by sodium dithionite (10 mM). The minor acid phosphatase activity (designated SP-II) present in extracts of Gaucher spleen has properties similar to those of the major species of acid phosphatase activity contained in serum from patients with Gaucher's disease: (1) it binds firmly to cation exchange columns (eluted by 0.5 M sodium chloride); (2) it exhibits a pH optimum of 5.0--6.0; (3) it is inhibited by sodium fluoride and sodium dithionite; and (4) it is resistant to inhibition by beta-mercaptoethanol (2.1 M) and L(+)-tartaric acid (20 mM). In addition, a second form of acid phosphatase that is tartrate resistant was found to be elevated in Gaucher serum. This form of serum acid phosphatase did not bind to Sulphopropyl Sephadex, was found to be significantly resistant to beta-mercaptoethanol (2.1 M), and was only partially inhibited by sodium dithionite (10 mM). The findings reported here indicate that at least three distinct forms of acid phosphatase activity are elevated in Gaucher's disease. Furthermore, the minor acid phosphatase activity contained in spleen homogenates has properties very similar to

  18. Restoring enzyme activity in nonfunctional low erucic acid Brassica napus fatty acid elongase 1 by a single amino acid substitution.

    PubMed

    Katavic, Vesna; Mietkiewska, Elzbieta; Barton, Dennis L; Giblin, E Michael; Reed, Darwin W; Taylor, David C

    2002-11-01

    Genomic fatty acid elongation 1 (FAE1) clones from high erucic acid (HEA) Brassica napus, Brassica rapa and Brassica oleracea, and low erucic acid (LEA) B. napus cv. Westar, were amplified by PCR and expressed in yeast cells under the control of the strong galactose-inducible promoter. As expected, yeast cells expressing the FAE1 genes from HEA Brassica spp. synthesized very long chain monounsaturated fatty acids that are not normally found in yeast, while fatty acid profiles of yeast cells expressing the FAE1 gene from LEA B. napus were identical to control yeast samples. In agreement with published findings regarding different HEA and LEA B. napus cultivars, comparison of FAE1 protein sequences from HEA and LEA Brassicaceae revealed one crucial amino acid difference: the serine residue at position 282 of the HEA FAE1 sequences is substituted by phenylalanine in LEA B. napus cv. Westar. Using site directed mutagenesis, the phenylalanine 282 residue was substituted with a serine residue in the FAE1 polypeptide from B. napus cv. Westar, the mutated gene was expressed in yeast and GC analysis revealed the presence of very long chain monounsaturated fatty acids (VLCMFAs), indicating that the elongase activity was restored in the LEA FAE1 enzyme by the single amino acid substitution. Thus, for the first time, the low erucic acid trait in canola B. napus can be attributed to a single amino acid substitution which prevents the biosynthesis of the eicosenoic and erucic acids.

  19. Activation of Inactive Nitrogenase by Acid-Treated Component I

    PubMed Central

    Nagatani, H. H.; Shah, Vinod K.; Brill, Winston J.

    1974-01-01

    When Azotobacter vinelandii was derepressed for nitrogenase synthesis in a N-free medium containing tungstate instead of molybdate, an inactive component I was synthesized. Although this inactive component I could be activated in vivo upon addition of molybdate to the medium, it could not be activated in vitro when molybdate was added to the extracts. Activation occurred, however, when an acid-treated component I was added to extracts of cells derepressed in medium containing tungstate. Acid treatment completely abolished component I activity. Mutant strains UW45 and UW10 were unable to fix N2. Both strains synthesized normal levels of component II but produced inactive component I. Acid-treated component I activated inactive component I in extracts of mutant strain UW45 but not mutant strain UW10. This activating factor could be obtained from N2-fixing Klebsiella pneumoniae, Clostridium pasteurianum, and Rhodospirillum rubrum. PMID:4218230

  20. Synthesis and antituberculosis activity of new fatty acid amides.

    PubMed

    D'Oca, Caroline Da Ros Montes; Coelho, Tatiane; Marinho, Tamara Germani; Hack, Carolina Rosa Lopes; Duarte, Rodrigo da Costa; da Silva, Pedro Almeida; D'Oca, Marcelo Gonçalves Montes

    2010-09-01

    This work reports the synthesis of new fatty acid amides from C16:0, 18:0, 18:1, 18:1 (OH), and 18:2 fatty acids families with cyclic and acyclic amines and demonstrate for the first time the activity of these compounds as antituberculosis agents against Mycobacterium tuberculosis H(37)Rv, M. tuberculosis rifampicin resistance (ATCC 35338), and M. tuberculosis isoniazid resistance (ATCC 35822). The fatty acid amides derivate from ricinoleic acid were the most potent one among a series of tested compounds, with a MIC 6.25 microg/mL for resistance strains.

  1. Structural Requirements for the Procoagulant Activity of Nucleic Acids

    PubMed Central

    Gansler, Julia; Jaax, Miriam; Leiting, Silke; Appel, Bettina; Greinacher, Andreas; Fischer, Silvia; Preissner, Klaus T.

    2012-01-01

    Nucleic acids, especially extracellular RNA, are exposed following tissue- or vessel damage and have previously been shown to activate the intrinsic blood coagulation pathway in vitro and in vivo. Yet, no information on structural requirements for the procoagulant activity of nucleic acids is available. A comparison of linear and hairpin-forming RNA- and DNA-oligomers revealed that all tested oligomers forming a stable hairpin structure were protected from degradation in human plasma. In contrast to linear nucleic acids, hairpin forming compounds demonstrated highest procoagulant activities based on the analysis of clotting time in human plasma and in a prekallikrein activation assay. Moreover, the procoagulant activities of the DNA-oligomers correlated well with their binding affinity to high molecular weight kininogen, whereas the binding affinity of all tested oligomers to prekallikrein was low. Furthermore, four DNA-aptamers directed against thrombin, activated protein C, vascular endothelial growth factor and nucleolin as well as the naturally occurring small nucleolar RNA U6snRNA were identified as effective cofactors for prekallikrein auto-activation. Together, we conclude that hairpin-forming nucleic acids are most effective in promoting procoagulant activities, largely mediated by their specific binding to kininogen. Thus, in vivo application of therapeutic nucleic acids like aptamers might have undesired prothrombotic or proinflammatory side effects. PMID:23226277

  2. Antiproliferative activity of synthetic fatty acid amides from renewable resources.

    PubMed

    dos Santos, Daiane S; Piovesan, Luciana A; D'Oca, Caroline R Montes; Hack, Carolina R Lopes; Treptow, Tamara G M; Rodrigues, Marieli O; Vendramini-Costa, Débora B; Ruiz, Ana Lucia T G; de Carvalho, João Ernesto; D'Oca, Marcelo G Montes

    2015-01-15

    In the work, the in vitro antiproliferative activity of a series of synthetic fatty acid amides were investigated in seven cancer cell lines. The study revealed that most of the compounds showed antiproliferative activity against tested tumor cell lines, mainly on human glioma cells (U251) and human ovarian cancer cells with a multiple drug-resistant phenotype (NCI-ADR/RES). In addition, the fatty methyl benzylamide derived from ricinoleic acid (with the fatty acid obtained from castor oil, a renewable resource) showed a high selectivity with potent growth inhibition and cell death for the glioma cell line-the most aggressive CNS cancer.

  3. Activation of PPARα by Fatty Acid Accumulation Enhances Fatty Acid Degradation and Sulfatide Synthesis.

    PubMed

    Yang, Yang; Feng, Yuyao; Zhang, Xiaowei; Nakajima, Takero; Tanaka, Naoki; Sugiyama, Eiko; Kamijo, Yuji; Aoyama, Toshifumi

    2016-01-01

    Very-long-chain acyl-CoA dehydrogenase (VLCAD) catalyzes the first reaction in the mitochondrial fatty acid β-oxidation pathway. VLCAD deficiency is associated with the accumulation of fat in multiple organs and tissues, which results in specific clinical features including cardiomyopathy, cardiomegaly, muscle weakness, and hepatic dysfunction in infants. We speculated that the abnormal fatty acid metabolism in VLCAD-deficient individuals might cause cell necrosis by fatty acid toxicity. The accumulation of fatty acids may activate peroxisome proliferator-activated receptor (PPAR), a master regulator of fatty acid metabolism and a potent nuclear receptor for free fatty acids. We examined six skin fibroblast lines, derived from VLCAD-deficient patients and identified fatty acid accumulation and PPARα activation in these cell lines. We then found that the expression levels of three enzymes involved in fatty acid degradation, including long-chain acyl-CoA synthetase (LACS), were increased in a PPARα-dependent manner. This increased expression of LACS might enhance the fatty acyl-CoA supply to fatty acid degradation and sulfatide synthesis pathways. In fact, the first and last reactions in the sulfatide synthesis pathway are regulated by PPARα. Therefore, we also measured the expression levels of enzymes involved in sulfatide metabolism and the regulation of cellular sulfatide content. The levels of these enzymes and cellular sulfatide content both increased in a PPARα-dependent manner. These results indicate that PPARα activation plays defensive and compensative roles by reducing cellular toxicity associated with fatty acids and sulfuric acid. PMID:27644403

  4. Novel Bioactivity of Ellagic Acid in Inhibiting Human Platelet Activation

    PubMed Central

    Chang, Yi; Chen, Wei-Fan; Lin, Kuan-Hung; Hsieh, Cheng-Ying; Chou, Duen-Suey; Lin, Li-Jyun; Sheu, Joen-Rong; Chang, Chao-Chien

    2013-01-01

    Pomegranates are widely consumed either as fresh fruit or in beverage form as juice and wine. Ellagic acid possesses potent antioxidative properties; it is known to be an effective phytotherapeutic agent with antimutagenic and anticarcinogenic qualities. Ellagic acid (20 to 80 μM) exhibited a potent activity in inhibiting platelet aggregation stimulated by collagen; however, it did not inhibit platelet aggregation stimulated by thrombin, arachidonic acid, or U46619. Treatment with ellagic acid (50 and 80 μM) significantly inhibited platelet activation stimulated by collagen; this alteration was accompanied by the inhibition of relative [Ca2+]i mobilization, and the phosphorylation of phospholipase C (PLC)γ2, protein kinase C (PKC), mitogen-activated protein kinases (MAPKs), and Akt, as well as hydroxyl radical (OH●) formation. In addition, ellagic acid also inhibited p38 MAPK and Akt phosphorylation stimulated by hydrogen peroxide. By contrast, ellagic acid did not significantly affect PKC activation and platelet aggregation stimulated by PDBu. This study is the first to show that, in addition to being considered a possible agent for preventing tumor growth, ellagic acid possesses potent antiplatelet properties. It appears to initially inhibit the PLCγ2-PKC cascade and/or hydroxyl radical formation, followed by decreased phosphorylation of MAPKs and Akt, ultimately inhibiting platelet aggregation. PMID:23533502

  5. Biological Activities of Oleanolic Acid Derivatives from Calendula officinalis Seeds.

    PubMed

    Zaki, Ahmed; Ashour, Ahmed; Mira, Amira; Kishikawa, Asuka; Nakagawa, Toshinori; Zhu, Qinchang; Shimizu, Kuniyoshi

    2016-05-01

    Phytochemical examination of butanol fraction of Calendula officinalis seeds led to the isolation of two compounds identified as 28-O-β-D-glucopyranosyl-oleanolic acid 3-O-β-D-glucopyranosyl (1→3)-β-D-glucopyranosiduronic acid (CS1) and oleanolic acid 3-O-β-D-glucopyranosyl (1→3)-β-D-glucopyranosiduronic acid (CS2). Biological evaluation was carried out for these two compounds such as melanin biosynthesis inhibitory, hyaluronic acid production activities, anti obesity using lipase inhibition and adipocyte differentiation as well as evaluation of the protective effect against hydrogen peroxide induced neurotoxicity in neuro-2A cells. The results showed that, compound CS2 has a melanin biosynthesis stimulatory activity; however, compound CS1 has a potent stimulatory effect for the production of hyaluronic acid on normal human dermal fibroblast from adult (NHDF-Ad). Both compounds did not show any inhibitory effect on both lipase and adipocyte differentiation. Compound CS2 could protect neuro-2A cells and increased cell viability against H2 O2 . These activities (melanin biosynthesis stimulatory and protective effect against H2 O2 of CS2 and hyaluronic acid productive activities of these triterpene derivatives) have been reported for the first time. Copyright © 2016 John Wiley & Sons, Ltd. PMID:26887328

  6. Biological Activities of Oleanolic Acid Derivatives from Calendula officinalis Seeds.

    PubMed

    Zaki, Ahmed; Ashour, Ahmed; Mira, Amira; Kishikawa, Asuka; Nakagawa, Toshinori; Zhu, Qinchang; Shimizu, Kuniyoshi

    2016-05-01

    Phytochemical examination of butanol fraction of Calendula officinalis seeds led to the isolation of two compounds identified as 28-O-β-D-glucopyranosyl-oleanolic acid 3-O-β-D-glucopyranosyl (1→3)-β-D-glucopyranosiduronic acid (CS1) and oleanolic acid 3-O-β-D-glucopyranosyl (1→3)-β-D-glucopyranosiduronic acid (CS2). Biological evaluation was carried out for these two compounds such as melanin biosynthesis inhibitory, hyaluronic acid production activities, anti obesity using lipase inhibition and adipocyte differentiation as well as evaluation of the protective effect against hydrogen peroxide induced neurotoxicity in neuro-2A cells. The results showed that, compound CS2 has a melanin biosynthesis stimulatory activity; however, compound CS1 has a potent stimulatory effect for the production of hyaluronic acid on normal human dermal fibroblast from adult (NHDF-Ad). Both compounds did not show any inhibitory effect on both lipase and adipocyte differentiation. Compound CS2 could protect neuro-2A cells and increased cell viability against H2 O2 . These activities (melanin biosynthesis stimulatory and protective effect against H2 O2 of CS2 and hyaluronic acid productive activities of these triterpene derivatives) have been reported for the first time. Copyright © 2016 John Wiley & Sons, Ltd.

  7. Hermetic atomism: Christian Adolph Balduin (1632-1682), Aurum Aurae, and the 1674 phosphor.

    PubMed

    Keller, Vera

    2014-11-01

    The synthesis of phosphors, or light-bearing matter, figured largely among the activities of early scientific societies and within the first scientific journals. They were prestige objects during the formative institutionalisation of experimental natural philosophy. Nevertheless, early phosphors have often appeared within the historiography of chemistry as a throwback to an earlier era. They have been represented as a fundamental epistemic and theoretical divide between a mystical alchemy (exemplified by Christian Adolph Balduin) and modern chemistry (prefigured by progressives such as Robert Boyle). The parallel phosphoric researches of Boyle and Balduin belie this divide. Recovering the theoretical context of Balduin's phosphor can both resituate it in relation to phosphoric research of the 1670s and 1680s, as well as further illuminate the intellectual sources and development of chymical atomism.

  8. Long afterglow properties of Zn2GeO4:Mn2+, Cr3+ phosphor

    NASA Astrophysics Data System (ADS)

    Cong, Yan; He, Yangyang; Dong, Bin; Xiao, Yu; Wang, Limei

    2015-04-01

    Zn2GeO4:Mn2+, Cr3+ phosphors were prepared by conventional solid state reaction and the photoluminescence properties were investigated. The Mn2+ activated Zn2GeO4 phosphors exhibited green emission at 533 nm due to the 4T1(4G) → 6A1(6S) transition of Mn2+ ions. With Cr3+ co-doping in Zn2GeO4 host, long afterglow characteristics were found from the same transition of Mn2+. The TL results revealed the presence of same traps in the phosphor, and the doping of Cr3+ ions deepened the VGe traps. The native defect VGe as a hole traps is responsible for the long afterglow emission in Zn2GeO4:Mn2+, Cr3+ phosphor. The possible mechanism of this phosphor has also been discussed.

  9. Hermetic atomism: Christian Adolph Balduin (1632-1682), Aurum Aurae, and the 1674 phosphor.

    PubMed

    Keller, Vera

    2014-11-01

    The synthesis of phosphors, or light-bearing matter, figured largely among the activities of early scientific societies and within the first scientific journals. They were prestige objects during the formative institutionalisation of experimental natural philosophy. Nevertheless, early phosphors have often appeared within the historiography of chemistry as a throwback to an earlier era. They have been represented as a fundamental epistemic and theoretical divide between a mystical alchemy (exemplified by Christian Adolph Balduin) and modern chemistry (prefigured by progressives such as Robert Boyle). The parallel phosphoric researches of Boyle and Balduin belie this divide. Recovering the theoretical context of Balduin's phosphor can both resituate it in relation to phosphoric research of the 1670s and 1680s, as well as further illuminate the intellectual sources and development of chymical atomism. PMID:25509635

  10. Activity of earthworm in Latosol under simulated acid rain stress.

    PubMed

    Zhang, Jia-En; Yu, Jiayu; Ouyang, Ying

    2015-01-01

    Acid rain is still an issue of environmental concerns. This study investigated the impacts of simulated acid rain (SAR) upon earthworm activity from the Latosol (acidic red soil). Laboratory experiment was performed by leaching the soil columns grown with earthworms (Eisenia fetida) at the SAR pH levels ranged from 2.0 to 6.5 over a 34-day period. Results showed that earthworms tended to escape from the soil and eventually died for the SAR at pH = 2.0 as a result of acid toxicity. The catalase activity in the earthworms decreased with the SAR pH levels, whereas the superoxide dismutases activity in the earthworms showed a fluctuate pattern: decreasing from pH 6.5 to 5.0 and increasing from pH 5.0 to 4.0. Results implied that the growth of earthworms was retarded at the SAR pH ≤ 3.0.

  11. Spectroscopic studies on the antioxidant activity of ellagic acid

    NASA Astrophysics Data System (ADS)

    Kilic, Ismail; Yeşiloğlu, Yeşim; Bayrak, Yüksel

    2014-09-01

    Ellagic acid (EA, C14H6O8) is a natural dietary polyphenol whose benefits in a variety of diseases shown in epidemiological and experimental studies involve anti-inflammation, anti-proliferation, anti-angiogenesis, anticarcinogenesis and anti-oxidation properties. In vitro radical scavenging and antioxidant capacity of EA were clarified using different analytical methodologies such as total antioxidant activity determination by ferric thiocyanate, hydrogen peroxide scavenging, 1,1-diphenyl-2-picryl-hydrazyl free radical (DPPH) scavenging, 2,2‧-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical scavenging activity and superoxide anion radical scavenging, ferrous ions (Fe2+) chelating activity and ferric ions (Fe3+) reducing ability. EA inhibited 71.2% lipid peroxidation of a linoleic acid emulsion at 45 μg/mL concentration. On the other hand, butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA), α-tocopherol and ascorbic acid displayed 69.8%, 66.8%, 64.5% and 59.7% inhibition on the peroxidation of linoleic acid emulsion at the same concentration, respectively. In addition, EA had an effective DPPH• scavenging, ABTSrad + scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging, ferric ions (Fe3+) reducing power and ferrous ions (Fe2+) chelating activities. Also, those various antioxidant activities were compared to BHA, BHT, α-tocopherol and ascorbic acid as references antioxidant compounds. These results suggested that EA can be used in the pharmacological, food industry and medicine because of these properties.

  12. Recombinant Trichoderma harzianum endoglucanase I (Cel7B) is a highly acidic and promiscuous carbohydrate-active enzyme.

    PubMed

    Pellegrini, Vanessa O A; Serpa, Viviane Isabel; Godoy, Andre S; Camilo, Cesar M; Bernardes, Amanda; Rezende, Camila A; Junior, Nei Pereira; Franco Cairo, João Paulo L; Squina, Fabio M; Polikarpov, Igor

    2015-11-01

    Trichoderma filamentous fungi have been investigated due to their ability to secrete cellulases which find various biotechnological applications such as biomass hydrolysis and cellulosic ethanol production. Previous studies demonstrated that Trichoderma harzianum IOC-3844 has a high degree of cellulolytic activity and potential for biomass hydrolysis. However, enzymatic, biochemical, and structural studies of cellulases from T. harzianum are scarce. This work reports biochemical characterization of the recombinant endoglucanase I from T. harzianum, ThCel7B, and its catalytic core domain. The constructs display optimum activity at 55 °C and a surprisingly acidic pH optimum of 3.0. The full-length enzyme is able to hydrolyze a variety of substrates, with high specific activity: 75 U/mg for β-glucan, 46 U/mg toward xyloglucan, 39 U/mg for lichenan, 26 U/mg for carboxymethyl cellulose, 18 U/mg for 4-nitrophenyl β-D-cellobioside, 16 U/mg for rye arabinoxylan, and 12 U/mg toward xylan. The enzyme also hydrolyzed filter paper, phosphoric acid swollen cellulose, Sigmacell 20, Avicel PH-101, and cellulose, albeit with lower efficiency. The ThCel7B catalytic domain displays similar substrate diversity. Fluorescence-based thermal shift assays showed that thermal stability is highest at pH 5.0. We determined kinetic parameters and analyzed a pattern of oligosaccharide substrates hydrolysis, revealing cellobiose as a final product of C6 degradation. Finally, we visualized effects of ThCel7B on oat spelt using scanning electron microscopy, demonstrating the morphological changes of the substrate during the hydrolysis. The acidic behavior of ThCel7B and its considerable thermostability hold a promise of its industrial applications and other biotechnological uses under extremely acidic conditions. PMID:26156238

  13. Recombinant Trichoderma harzianum endoglucanase I (Cel7B) is a highly acidic and promiscuous carbohydrate-active enzyme.

    PubMed

    Pellegrini, Vanessa O A; Serpa, Viviane Isabel; Godoy, Andre S; Camilo, Cesar M; Bernardes, Amanda; Rezende, Camila A; Junior, Nei Pereira; Franco Cairo, João Paulo L; Squina, Fabio M; Polikarpov, Igor

    2015-11-01

    Trichoderma filamentous fungi have been investigated due to their ability to secrete cellulases which find various biotechnological applications such as biomass hydrolysis and cellulosic ethanol production. Previous studies demonstrated that Trichoderma harzianum IOC-3844 has a high degree of cellulolytic activity and potential for biomass hydrolysis. However, enzymatic, biochemical, and structural studies of cellulases from T. harzianum are scarce. This work reports biochemical characterization of the recombinant endoglucanase I from T. harzianum, ThCel7B, and its catalytic core domain. The constructs display optimum activity at 55 °C and a surprisingly acidic pH optimum of 3.0. The full-length enzyme is able to hydrolyze a variety of substrates, with high specific activity: 75 U/mg for β-glucan, 46 U/mg toward xyloglucan, 39 U/mg for lichenan, 26 U/mg for carboxymethyl cellulose, 18 U/mg for 4-nitrophenyl β-D-cellobioside, 16 U/mg for rye arabinoxylan, and 12 U/mg toward xylan. The enzyme also hydrolyzed filter paper, phosphoric acid swollen cellulose, Sigmacell 20, Avicel PH-101, and cellulose, albeit with lower efficiency. The ThCel7B catalytic domain displays similar substrate diversity. Fluorescence-based thermal shift assays showed that thermal stability is highest at pH 5.0. We determined kinetic parameters and analyzed a pattern of oligosaccharide substrates hydrolysis, revealing cellobiose as a final product of C6 degradation. Finally, we visualized effects of ThCel7B on oat spelt using scanning electron microscopy, demonstrating the morphological changes of the substrate during the hydrolysis. The acidic behavior of ThCel7B and its considerable thermostability hold a promise of its industrial applications and other biotechnological uses under extremely acidic conditions.

  14. Activation of the Glutamic Acid-Dependent Acid Resistance System in Escherichia coli BL21(DE3) Leads to Increase of the Fatty Acid Biotransformation Activity

    PubMed Central

    Woo, Ji-Min; Kim, Ji-Won; Song, Ji-Won; Blank, Lars M.; Park, Jin-Byung

    2016-01-01

    The biosynthesis of carboxylic acids including fatty acids from biomass is central in envisaged biorefinery concepts. The productivities are often, however, low due to product toxicity that hamper whole-cell biocatalyst performance. Here, we have investigated factors that influence the tolerance of Escherichia coli to medium chain carboxylic acid (i.e., n-heptanoic acid)-induced stress. The metabolic and genomic responses of E. coli BL21(DE3) and MG1655 grown in the presence of n-heptanoic acid indicated that the GadA/B-based glutamic acid-dependent acid resistance (GDAR) system might be critical for cellular tolerance. The GDAR system, which is responsible for scavenging intracellular protons by catalyzing decarboxylation of glutamic acid, was inactive in E. coli BL21(DE3). Activation of the GDAR system in this strain by overexpressing the rcsB and dsrA genes, of which the gene products are involved in the activation of GadE and RpoS, respectively, resulted in acid tolerance not only to HCl but also to n-heptanoic acid. Furthermore, activation of the GDAR system allowed the recombinant E. coli BL21(DE3) expressing the alcohol dehydrogenase of Micrococcus luteus and the Baeyer-Villiger monooxygenase of Pseudomonas putida to reach 60% greater product concentration in the biotransformation of ricinoleic acid (i.e., 12-hydroxyoctadec-9-enoic acid (1)) into n-heptanoic acid (5) and 11-hydroxyundec-9-enoic acid (4). This study may contribute to engineering E. coli-based biocatalysts for the production of carboxylic acids from renewable biomass. PMID:27681369

  15. The antimicrobial activities of the cinnamaldehyde adducts with amino acids.

    PubMed

    Wei, Qing-Yi; Xiong, Jia-Jun; Jiang, Hong; Zhang, Chao; Wen Ye

    2011-11-01

    Cinnamaldehyde is a well-established natural antimicrobial compound. It is probable for cinnamaldehyde to react with amino acid forming Schiff base adduct in real food system. In this paper, 9 such kind of adducts were prepared by the direct reaction of amino acids with cinnamaldehyde at room temperature. Their antimicrobial activities against Bacillus subtilis, Escherichia coli and Saccharomyces cerevisiae were evaluated with benzoic acid as a reference. The adducts showed a dose-dependent activities against the three microbial strains. Both cinnamaldehyde and their adducts were more active against B. subtilis than on E. coli, and their antimicrobial activities were higher at lower pH. Both cinnamaldehyde and its adducts were more active than benzoic acid at the same conditions. The adduct compound A was non-toxic by primary oral acute toxicity study in mice. However, in situ effect of the adduct compound A against E. coli was a little lower than cinnamaldehyde in fish meat. This paper for the first time showed that the cinnamaldehyde adducts with amino acids had similar strong antimicrobial activities as cinnamaldehyde, which may provide alternatives to cinnamaldehyde in food to avoid the strong unacceptable odor of cinnamaldehyde. PMID:21856030

  16. Catalytic Ethanol Dehydration over Different Acid-activated Montmorillonite Clays.

    PubMed

    Krutpijit, Chadaporn; Jongsomjit, Bunjerd

    2016-01-01

    In the present study, the catalytic dehydration of ethanol to obtain ethylene over montmorillonite clays (MMT) with mineral acid activation including H2SO4 (SA-MMT), HCl (HA-MMT) and HNO3 (NA-MMT) was investigated at temperature range of 200 to 400°C. It revealed that HA-MMT exhibited the highest catalytic activity. Ethanol conversion and ethylene selectivity were found to increase with increased reaction temperature. At 400°C, the HA-MMT yielded 82% of ethanol conversion having 78% of ethylene yield. At lower temperature (i.e. 200 to 300°C), diethyl ether (DEE) was a major product. The highest activity obtained from HA-MMT can be attributed to an increase of weak acid sites and acid density by the activation of MMT with HCl. It can be also proven by various characterization techniques that in most case, the main structure of MMT did not alter by acid activation (excepted for NA-MMT). Upon the stability test for 72 h during the reaction, the MMT and HA-MMT showed only slight deactivation due to carbon deposition. Hence, the acid activation of MMT by HCl is promising to enhance the catalytic dehydration of ethanol. PMID:27041515

  17. Radioluminescent nuclear batteries with different phosphor layers

    NASA Astrophysics Data System (ADS)

    Hong, Liang; Tang, Xiao-Bin; Xu, Zhi-Heng; Liu, Yun-Peng; Chen, Da

    2014-11-01

    A radioluminescent nuclear battery based on the beta radioluminescence of phosphors is presented, and which consists of 147Pm radioisotope, phosphor layers, and GaAs photovoltaic cell. ZnS:Cu and Y2O2S:Eu phosphor layers for various thickness were fabricated. To investigate the effect of phosphor layer parameters on the battery, the electrical properties were measured. Results indicate that the optimal thickness ranges for the ZnS:Cu and Y2O2S:Eu phosphor layers are 12 mg cm-2 to 14 mg cm-2 and 17 mg cm-2 to 21 mg cm-2, respectively. ZnS:Cu phosphor layer exhibits higher fluorescence efficiency compared with the Y2O2S:Eu phosphor layer. Its spectrum properly matches the spectral response of GaAs photovoltaic cell. As a result, the battery with ZnS:Cu phosphor layer indicates higher energy conversion efficiency than that with Y2O2S:Eu phosphor layer. Additionally, the mechanism of the phosphor layer parameters that influence the output performance of the battery is discussed through the Monte Carlo method and transmissivity test.

  18. Antileishmanial activity of diterpene acids in copaiba oil

    PubMed Central

    dos Santos, Adriana Oliveira; Izumi, Erika; Ueda-Nakamura, Tânia; Dias-Filho, Benedito Prado; da Veiga-Júnior, Valdir Florêncio; Nakamura, Celso Vataru

    2013-01-01

    Leishmaniasis is a neglected tropical disease. According to the World Health Organization, there are approximately 1.5-two million new cases of cutaneous leishmaniasis each year worldwide. Chemotherapy against leishmaniasis is based on pentavalent antimonials, which were developed more than a century ago. The goals of this study were to investigate the antileishmanial activity of diterpene acids in copaiba oil, as well as some possible targets of their action against Leishmania amazonensis. Methyl copalate and agathic, hydroxycopalic, kaurenoic, pinifolic and polyaltic acids isolated from Copaifera officinales oleoresins were utilised. Ultrastructural changes and the specific organelle targets of diterpenes were investigated with electron microscopy and flow cytometry, respectively. All compounds had some level of activity against L. amazonensis. Hydroxycopalic acid and methyl copalate demonstrated the most activity against promastigotes and had 50% inhibitory concentration (IC50) values of 2.5 and 6.0 µg/mL, respectively. However, pinifolic and kaurenoic acid demonstrated the most activity against axenic amastigote and had IC50 values of 3.5 and 4.0 µg/mL, respectively. Agathic, kaurenoic and pinifolic acid caused significant increases in plasma membrane permeability and mitochondrial membrane depolarisation of the protozoan. In conclusion, copaiba oil and its diterpene acids should be explored for the development of new antileishmanial drugs. PMID:23440116

  19. The antimicrobial activity of liposomal lauric acids against Propionibacterium acnes.

    PubMed

    Yang, Darren; Pornpattananangkul, Dissaya; Nakatsuji, Teruaki; Chan, Michael; Carson, Dennis; Huang, Chun-Ming; Zhang, Liangfang

    2009-10-01

    This study evaluated the antimicrobial activity of lauric acid (LA) and its liposomal derivatives against Propionibacterium acnes (P. acnes), the bacterium that promotes inflammatory acne. First, the antimicrobial study of three free fatty acids (lauric acid, palmitic acid and oleic acid) demonstrated that LA gives the strongest bactericidal activity against P. acnes. However, a setback of using LA as a potential treatment for inflammatory acne is its poor water solubility. Then the LA was incorporated into a liposome formulation to aid its delivery to P. acnes. It was demonstrated that the antimicrobial activity of LA was not only well maintained in its liposomal derivatives but also enhanced at low LA concentration. In addition, the antimicrobial activity of LA-loaded liposomes (LipoLA) mainly depended on the LA loading concentration per single liposomes. Further study found that the LipoLA could fuse with the membranes of P. acnes and release the carried LA directly into the bacterial membranes, thereby killing the bacteria effectively. Since LA is a natural compound that is the main acid in coconut oil and also resides in human breast milk and liposomes have been successfully and widely applied as a drug delivery vehicle in the clinic, the LipoLA developed in this work holds great potential of becoming an innate, safe and effective therapeutic medication for acne vulgaris and other P. acnes associated diseases. PMID:19665786

  20. Urease inhibitory activities of β-boswellic acid derivatives

    PubMed Central

    2013-01-01

    Background and the purpose of the study Boswellia carterii have been used in traditional medicine for many years for management different gastrointestinal disorders. In this study, we wish to report urease inhibitory activity of four isolated compound of boswellic acid derivative. Methods 4 pentacyclic triterpenoid acids were isolated from Boswellia carterii and identified by NMR and Mass spectroscopic analysis (compounds 1, 3-O-acetyl-9,11-dehydro-β-boswellic acid; 2, 3-O-acetyl-11-hydroxy-β-boswellic acid; 3. 3-O- acetyl-11-keto-β-boswellic acid and 4, 11-keto-β-boswellic acid. Their inhibitory activity on Jack bean urease were evaluated. Docking and pharmacophore analysis using AutoDock 4.2 and Ligandscout 3.03 programs were also performed to explain possible mechanism of interaction between isolated compounds and urease enzyme. Results It was found that compound 1 has the strongest inhibitory activity against Jack bean urease (IC50 = 6.27 ± 0.03 μM), compared with thiourea as a standard inhibitor (IC50 = 21.1 ± 0.3 μM). Conclusion The inhibition potency is probably due to the formation of appropriate hydrogen bonds and hydrophobic interactions between the investigated compounds and urease enzyme active site and confirms its traditional usage. PMID:23351363